Infra-Red Fixed Points in an Asymptotically Non-Free Theory

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STATA软件中xtreg指令的后处理工具-xtreg后处理指令详述说明书

TitleDescriptionThe following postestimation commands are of special interest after xtreg: command descriptionxttest0Breusch and Pagan LM test for random effectsFor information about this command,see below.In addition,the following standard postestimation commands are available:command descriptionadjust1adjusted predictions of xβ∗estat AIC,BIC,VCE,and estimation sample summaryestimates cataloging estimation resultshausman Hausman’s speciﬁcation testlincom point estimates,standard errors,testing,and inference for linear combinationsof coefﬁcientslrtest likelihood-ratio testmfx marginal effects or elasticitiesnlcom point estimates,standard errors,testing,and inference for nonlinear combinations of coefﬁcientspredict predictions,residuals,inﬂuence statistics,and other diagnostic measurespredictnl point estimates,standard errors,testing,and inference for generalized predictions test Wald tests for simple and composite linear hypothesestestnl Wald tests of nonlinear hypotheses1adjust does not work with time-series operators.∗estat ic may not be used after xtreg with the be,pa,or re options.See the corresponding entries in the Stata Base Reference Manual for details.Special-interest postestimation commandsxttest0,for use after xtreg,re,presents the Breusch and Pagan(1980)Lagrange-multiplier test for random effects,a test that Var(νi)=0.304xtreg postestimation—Postestimation tools for xtreg305 Syntax for predictFor all but the population-averaged modelpredict type newvar if in ,statistic nooffsetPopulation-averaged modelpredict type newvar if in ,PA statistic nooffsetstatistic descriptionxb x j b,ﬁtted values;the defaultstdp standard error of theﬁtted valuesue u i+e it,the combined residual∗xbu x j b+u i,prediction including effect∗u u i,theﬁxed-or random-error component∗e e it,the overall error componentUnstarred statistics are available both in and out of sample;type predict...if e(sample)...if wantedonly for the estimation sample.Starred statistics are calculated only for the estimation sample,even whenif e(sample)is not speciﬁed.PA statistic descriptionxb linear predictionstdp standard error of the linear predictionscoreﬁrst derivative of the log likelihood with respect to x jβThese statistics are available both in and out of sample;type predict...if e(sample)...if wanted onlyfor the estimation sample.Options for predictxb calculates the linear prediction,that is,a+bx it.This is the default for all except the population-averaged model.stdp calculates the standard error of the linear prediction.Note that,in the case of theﬁxed-effects model,this excludes the variance due to uncertainty about the estimate of u i.ue calculates the prediction of u i+e it.xbu calculates the prediction of a+bx it+u i,the prediction including theﬁxed-or random-component.u calculates the prediction of u i,the estimatedﬁxed-or random-effect.e calculates the prediction of e it.score calculates the equation-level score,u j=∂ln L j(x jβ)/∂(x jβ).nooffset is relevant only if you speciﬁed offset(varname)for xtreg,pa.It modiﬁes the calculations made by predict so that they ignore the offset variable;the linear prediction is treated as x it b rather than x it b+offset it.306xtreg postestimation—Postestimation tools for xtregSyntax for xttest0xttest0RemarksExample1Continuing with our xtreg,re estimation example(example4)in xtreg,we can see that xttest0 will report a test ofνi=0.In case we have any doubts,we could type.xttest0Breusch and Pagan Lagrangian multiplier test for random effects:ln_wage[idcode,t]=Xb+u[idcode]+e[idcode,t]Estimated results:Var sd=sqrt(Var)ln_wage.2283326.4778416e.0845038.2906954u.066514.2579031Test:Var(u)=0chi2(1)=14779.98Prob>chi2=0.0000Example2More importantly,after xtreg,re estimation,hausman will perform the Hausman speciﬁcation test.If our model is correctly speciﬁed,and ifνi is uncorrelated with x it,the(subset of)coefﬁcients that are estimated by theﬁxed-effects estimator and the same coefﬁcients that are estimated here should not statistically differ:.xtreg ln_w grade age*ttl_exp*tenure*black not_smsa south,re(output omitted).estimates store random_effects.xtreg ln_w grade age*ttl_exp*tenure*black not_smsa south,fe(output omitted)xtreg postestimation—Postestimation tools for xtreg307.hausman.random_effectsCoefficients(b)(B)(b-B)sqrt(diag(V_b-V_B)).random_eff~s Difference S.E.age.0359987.036806-.0008073.0013177age2-.000723-.0007133-9.68e-06.0000184ttl_exp.0334668.0290207.0044461.001711ttl_exp2.0002163.0003049-.0000886.000053tenure.0357539.039252-.0034981.0005797tenure2-.0019701-.0020035.0000334.0000373not_smsa-.0890108-.1308263.0418155.0062745south-.0606309-.0868927.0262618.0081346b=consistent under Ho and Ha;obtained from xtregB=inconsistent under Ha,efficient under Ho;obtained from xtreg Test:Ho:difference in coefficients not systematicchi2(8)=(b-B)’[(V_b-V_B)^(-1)](b-B)=149.44Prob>chi2=0.0000We can reject the hypothesis that the coefﬁcients are the same.Before turning to what this means, note that hausman listed the coefﬁcients estimated by the two models.It did not,however,list grade and race.hausman did not make a mistake;in the Hausman test,we compare only the coefﬁcients estimated by both techniques.What does this mean?We have an unpleasant choice:we can admit that our model is misspeciﬁed—that we have not parameterized it correctly—or we can hold that our speciﬁca-tion is correct,in which case the observed differences must be due to the zero-correlation ofνi and the x it assumption.u Technical NoteWe can also mechanically explore the underpinnings of the test’s dissatisfaction.In the comparison table from hausman,note that it is the coefﬁcients on not smsa and south that exhibit the largest differences.In equation(1 )of[XT]xtreg,we showed how to decompose a model into within and between effects.Let us do that with these two variables,assuming that changes in the average have one effect while transitional changes have another:.egen avgnsmsa=mean(not_smsa),by(idcode).generate devnsma=not_smsa-avgnsmsa(8missing values generated).egen avgsouth=mean(south),by(idcode).generate devsouth=south-avgsouth(8missing values generated)308xtreg postestimation—Postestimation tools for xtreg.xtreg ln_w grade age*ttl_exp*tenure*black avgnsm devnsm avgsou devsouRandom-effects GLS regression Number of obs=28091Group variable(i):idcode Number of groups=4697R-sq:within=0.1723Obs per group:min=1 between=0.4809avg= 6.0overall=0.3737max=15 Random effects u_i~Gaussian Wald chi2(12)=9319.69corr(u_i,X)=0(assumed)Prob>chi2=0.0000 ln_wage Coef.Std.Err.z P>|z|[95%Conf.Interval]grade.0631716.001790335.290.000.0596627.0666805age.0375196.003118612.030.000.0314072.043632age2-.0007248.00005-14.500.000-.0008228-.0006269 ttl_exp.0286542.002420711.840.000.0239097.0333987ttl_exp2.0003222.0001162 2.770.006.0000945.0005499tenure.0394424.00175422.490.000.0360045.0428803tenure2-.0020081.0001192-16.850.000-.0022417-.0017746black-.0545938.0102099-5.350.000-.0746048-.0345827 avgnsmsa-.1833238.0109337-16.770.000-.2047533-.1618942devnsma-.0887596.0095071-9.340.000-.1073932-.070126avgsouth-.1011235.0098787-10.240.000-.1204855-.0817616devsouth-.0598538.0109054-5.490.000-.081228-.0384796 _cons.268298.0495776 5.410.000.1711277.3654683sigma_u.25791607sigma_e.29069544rho.44046285(fraction of variance due to u_i)We will leave the reinterpretation of this model to you,except to note that if we were really going to sell this model,we would have to explain why the between and within effects are different.Focusing on residence in a non SMSA,we might tell a story about rural people being paid less and continuing to get paid less when they move to the SMSA.Given our panel data,we could create variables to measure this(an indicator for moved from non SMSA to SMSA)and to measure the effects.In our assessment of this model,we should think about women in the cities moving to the country and their relative productivity in a bucolic setting.xtreg postestimation—Postestimation tools for xtreg309 In any case,the Hausman test now is.estimates store new_random_effects.xtreg ln_w grade age*ttl_exp*tenure*black avgnsm devnsm avgsou devsou,fe(output omitted).hausman.new_random_effectsCoefficients(b)(B)(b-B)sqrt(diag(V_b-V_B)).new_random~s Difference S.E.age.0359987.0375196-.001521.0013198age2-.000723-.0007248 1.84e-06.0000184ttl_exp.0334668.0286542.0048126.0017127ttl_exp2.0002163.0003222-.0001059.0000531tenure.0357539.0394424-.0036885.0005839tenure2-.0019701-.0020081.000038.0000377devnsma-.0890108-.0887596-.0002512.0006826devsouth-.0606309-.0598538-.0007771.0007612b=consistent under Ho and Ha;obtained from xtregB=inconsistent under Ha,efficient under Ho;obtained from xtreg Test:Ho:difference in coefficients not systematicchi2(8)=(b-B)’[(V_b-V_B)^(-1)](b-B)=92.52Prob>chi2=0.0000We have mechanically succeeded in greatly reducing theχ2,but not by enough.The major differences now are in the age,experience,and tenure effects.We already knew this problem existed because of the ever-increasing effect of experience.More careful parameterization work rather than simply including squares needs to be done.uMethods and FormulasAll postestimation commands listed above are implemented as ado-ﬁles.xttest0xttest0reports the Lagrange-multiplier test for random effects developed by Breusch and Pagan (1980)and as modiﬁed by Baltagi and Li(1990).The modely it=α+x itβ+νitis estimated via OLS,and then the quantityλLM=(nT)22 A21( i T2i)−nTis calculated,whereA1=1− n i=1( T i t=1v it)2i t v2it310xtreg postestimation—Postestimation tools for xtregThe Baltagi and Li modiﬁcation allows for unbalanced data and reduces to the standard formulaλLM=nT2(T−1)i( t v it)2i t v2it−1 2when T i=T(balanced data).Under the null hypothesis,λLM is distributedχ2(1).ReferenceBaltagi,B.H.and Q.Li.1990.A Lagrange-multiplier test for the error components model with incomplete panels.Econometric Reviews9(1):103–107.Breusch,T.and A.Pagan.1980.The Lagrange-multiplier test and its applications to model speciﬁcation in econometrics.Review of Economic Studies47:239–253.Hausman,J.A.1978.Speciﬁcation tests in econometrics.Econometrica46:1251–1271.Also SeeComplementary:[XT]xtreg,[R]adjust,[R]estimates,[R]hausman,[R]lincom,[R]lrtest,[R]mfx,[R]nlcom,[R]predictnl,[R]test,[R]testnlBackground:[U]13.5Accessing coefﬁcients and standard errors,[U]20Estimation and postestimation commands,[R]estat,[R]predict。

Junctions of three quantum wires

2 tion on the nature of the ﬁxed points for a range of the parameter g , and that diﬀerent methods that we describe in the paper are needed to shed light onto the nature of the strong coupling ﬁxed points. In Sec. VI we establish the mapping of the Y-junction model onto the DHM and deduce its consequences for the phase diagram of the Yjunction model. In Sec. VII we introduce the study of the system by looking at the boundary conditions satisﬁed by the bosonic ﬁelds at the junction. In Sec. VIII we discuss the twisted structure of the Hilbert space that is manifest in the compactiﬁcation of the bosons so as to take proper care of the fermionic statistics of the electrons in the wires. In Sec. IX we introduce what we refer to as the method of delayed evaluation of boundary conditions (DEBC), which is less reliant on the apparatus of BCFT. In Sec. X we apply all the results from the previous sections to analyze the RG ﬁxed points in the junction problem. We also show in this section that asymmetries in the couplings between the three wires are irrelevant at low energies and temperatures, so the simple Z3 symmetric model of the system may indeed be a good description of realistic junctions. In Sec. XI we use simple arguments based on energy conservation to obtain constraints on the conductance tensor. We show that all the ﬁxed points that we are able to understand in this paper correspond to physical situations where no energy is transfered to neutral (non-charge carrying) modes in the quantum wires. In Sec. XII we discuss how the conductance tensors are modiﬁed if the Luttinger liquid wires are connected to Fermi liquid leads far from the junction. Depending on details of the potential experiment, this may be a better model. In Sec. XIII we present and discuss open problems. In Appendix A we give results on the non-interacting version of our model. In Appendix B we review boundary conformal ﬁeld theory. In Appendix C we review the boundary conformal ﬁeld theory of standard free bosons. In Appendix D we review the boundary conformal ﬁeld theory approach to calculating the conductance. In Appendix E we discuss the related problem of a Y-junction of quantum Hall edge states.

艾里光束

光束构建自会聚光束，因此着重关注它的自弯曲传输特性，以期望艾里光束在自弯曲的过程中实现能量的自会聚
• The equivalent envelope Gaussian beam (EEGB) defined as the Gaussian beam with full-width at half maximum (FWHM) equal to the diameter of the ring-Airy beam and the equivalent peak contrast Gaussian beam (ECGB), which, in the linear regime, reaches the same peak intensity contrast value at the focus
原理以及计算方法
• 理论：在量子力学框架下，描述微观粒子运动的自由空间薛定谔方程的一维形式是 • • 其中m是粒子的质量，当初始条件输入艾里光波，在演化过程中可以得到一个不扩展并且能够横向自加速的波包解。这是1979年由Berry和Balazs首次在理论上提出的，他们还解释了理论上得到的弯曲轨迹实际上是初始时刻处于不同位置粒子做直线运动得到的轨迹形成的包络，每一点的强度是相应粒子波包在此位置的相干叠加。
Figure 6 | Comparative plot of intensity distributions. Radial intensity distribution of the ring-Airy, EEGB and ECGB used in the simulations.
Figure 1 | Focus shift in the non-linear regime. Focus position as a function of the input power for the ring-Airy beam (black squares) and the two Gaussian beams with equivalent contrast (red dots) and equivalent envelope (blue triangles).

Constants and Variations From Alpha to Omega

a rXiv:g r-qc/298v 123Sep22Constants and Variations:From Alpha to OmegaJohn D.Barrow DAMTP Centre for Mathematical Sciences Cambridge University Cambridge CB30WA UK February 7,2008Abstract We review some of the history and properties of theories for the vari-ation of the gravitation and ﬁne structure ’constants’.We highlight some general features of the cosmological models that exist in these theories with reference to recent quasar data that is consistent with time-variation in alpha since a redshift of 3.5.The behaviour of a simple class of varying-alpha cosmologies is outlined in the light of all the observational con-straints.We discuss the key role played by non-zero vacuum energy and curvature in turning oﬀthe variation of constants in these theories and the issue of comparing extra-galactic and local observational data.We also show why black hole thermodynamics does not enable us to distinguish between time variations of diﬀerent constants.1IntroductionThere are a number of reasons why the possibility of varying constants should be taken seriously [1].First,we know that the best candidates for uniﬁcation of the forces of nature in a quantum gravitational environment only seem to exist in ﬁnite form if there are many more dimensions of space than the three that we are familiar with.This means that the true constants of nature are deﬁned in higher dimensions and the three-dimensional shadows we observe are not fundamental and do not need to be constant.Any slow change in the scale of the extra dimensions would be revealed by measurable changes in our three-dimensional ’constants’.Second,we appreciate that some apparent constant might be determined partially or completely by some spontaneous symmetry-breaking processes in the very early universe.This introduces an irreducible1random element into the values of those constants.They may be diﬀerent in diﬀerent parts of the universe.The most dramatic manifestation of this process is provided by the chaotic and eternal inﬂationary universe scenarios.Third, any outcome of a theory of quantum gravity will be intrinsically probabilistic. It is often imagined that the probability distributions for observables will be very sharply peaked but this may not be the case for all possibilities.Thus,the value of G or˙G might be predicted to be spatially varying random variables. Fourth,the non-uniqueness of the vacuum state for the universe would allow other deals of the constants to have occurred in diﬀerent places.At present we have no idea why any of the constants of Nature take the numerical values they do.Fifth,the observational limits on possible variations are often very weak (although they can be made to sound strong by judicious parametrisations).For example,the cosmological limits on varying G tell us only that˙G/G≤10−2H0, where H0is the present Hubble rate.However,the last reason to consider varying constants is currently the most compelling.For theﬁrst time there is a body of detailed astronomical evidence for the time variation of a traditional constant.The observational programme of Webb et al[2,3]has completed detailed analyses of three separate quasar absorption line data sets taken at Keck andﬁnds persistent evidence consistent with theﬁne structure constant,α,having been smaller in the past,at z=1−3.5.The shift in the value ofαfor all the data sets is given provisionally by∆α/α=(−0.66±0.11)×10−5. This result is currently the subject of detailed analysis and reanalysis by the observers in order to search for possible systematic biases in the astrophysical environment or in the laboratory determinations of the spectral lines.Theﬁrst investigations of time-varying constants were those made by Lord Kelvin and others interested in possible time-variation of the speed of light at the end of the nineteenth century.In1935Milne devised a theory of gravity, of a form that we would now term’bimetric’,in which there were two times –one(t)for atomic phenomena,one(τ)for gravitational phenomena–linked byτ=log(t/t0).Milne[4]required that the’mass of the universe’(what we would now call the mass inside the particle horizon M≈c3G−1t)be constant. This required G∝t.Interestingly,in1937the biologist J.B.S.Haldane took a strong interest in this theory and wrote several papers[5]exploring its conse-quences for the evolution of life.The argued that biochemical activation energies might appear constant on the t timescale yet increase on theτtimescale,giving rise to a non-uniformity in the evolutionary process.Also at this time there was widespread familiarity with the mysterious’large numbers’O(1040)and O(1080)through the work of Eddington(although they hadﬁrst been noticed by Weyl[6]–see ref.[7]and[1]for the history).These two ingredients were merged by Dirac in1937in a famous development(supposedly written on his honeymoon)that proposed that these large numbers(1040)were actually equal, up to small dimensionless factors.Thus,if we form N∼c3t/Gm n∼1080, the number of nucleons in the visible universe,and equate it to the square of N1∼e2/Gm2n∼1040,the ratio of the electrostatic and gravitational forces between two protons then we are led to conclude that one of the constants, e,G,c,h,m n must vary with time.Dirac[8]chose G∝t−1to carry the time2variation.Unfortunately,this hypothesis did not survive very long.EdwardTeller[9]pointed out that such a steep increase in G to the past led to huge in-creases in the Earth’s surface temperature in the past.The luminosity of the sunvaries as L∝G7and the radius of the Earth’s orbit as R∝G−1so the Earth’ssurface temperature T⊕varies as(L/R2)1/4∝G9/4∝t−9/4and would exceed the boiling point of water in the pre-Cambrian era.Life would be eliminated.Gamow subsequently suggested that the time variation needed to reconcile the large number coincidences be carried by e rather than G,but again this strong variation was soon shown to be in conﬂict with geophysical and radioactive de-cay data.This chapter was brought to an end by Dicke[10]who pointed out that the N∼N21large number coincidence was just the statement that t,the present age of the universe when our observations are being made,is of order the main sequence stellar lifetime,t ms∼(Gm2n/hc)−1h/m n c2∼1010yrs,and therefore inevitable for observers made from elements heavier than hydrogen and helium.Dirac never accepted this anthropic explanation for the large num-ber coincidences but curiously can be found making exactly the same type of anthropic argument to defend his own varying G theory by highly improbable arguments(that the Sun accretes material periodically during its orbit of the galaxy and this extra material cancels out the eﬀects of overheating in the past) in correspondence with Gamow in1967(see[1]for fuller details).Dirac’s proposal acted as a stimulus to theorists,like Jordan,Brans and Dicke[11],to develop rigorous theories which included the time variation of G self-consistently by modelling it as arising from the space-time variation of some scalarﬁeldφ(x,t)whose motion both conserved energy and momentum and created its own gravitationalﬁeld variations.In this respect the geometric structure of Einstein’s equations provides a highly constrained environment to introduce variations of’constants’.Whereas in Newtonian gravity we are at liberty to introduce a time-varying G(t)into the law of gravity byG(t)MmF=−T ab(2)c4then taking a covariant divergence and using∇a G ab=0,together with energy-momentum conservation(∇a T ab=0)requires that∇G≡0and no variationsare possible in eq.(2).Brans-Dicke theory is a familiar example of how the addition of an extra piece to T ab together with the dynamics of a G(φ)ﬁelds makes a varying G theory possible.Despite the simplicity of this lesson in the context of a varying G theory the lesson was not taken on board when considering the variations of other non-gravitational constants and the literature3is full of limits on their possible variation which have been derived by considering a theory in which the time-variation is just written into the equations which hold when the constant does not vary.Recently,the interest in the possibility thatαvaries in time has led to theﬁrst extensive exploration of simple self-consistent theories in which a variations occur through the variation of some scalarﬁeld. 2Brans-Dicke Theories2.1Equations and solutionsConsider the paradigmatic case of Brans-Dicke(BD)theory[11]toﬁx theoret-ical ideas about varying G.The form of the general solutions to the Friedmann metric in BD theories are fully understood[13],[14].There are three essential ﬁeld equations for the evolution of BD scalarﬁeldφ(t)and the expansion scale factor a(t)in a BD universe3˙a2φ−3˙a˙φ2˙φ2a2(3)¨φ+3˙a3+2ωBD(ρ−3p)(4)˙ρ+3˙a1+2ωBD/3φ(t)=φ0t[2(1−3Γ)/[4+3ω(1−Γ2)](10) At late times they approach particular exact power-law solutions for a(t)and φ(t)and the evolution is’Machian’in the sense that the cosmological evolution is driven by the matter content rather than by the kinetic energy of the freeφﬁeld.In the radiation era this particular solution is the standard general relativity solution:a(t)=t1/2;φ−1∝G=constant(11) For p=0the solutions have the forma(t)=t(2−n)/3;φ−1∝G∝t−n,(12) which continues until the curvature term takes over the expansion.Here,n is related to the constant Brans-DickeωBD parameter by2n≡An interesting particular example of this problem is given by the power-law solutions above for the case withΓ=−1.This is equivalent to the universe being dominated by a vacuum energy and leads to power-law accelerated expansion in BD theory witha(t)=t1more general theories in which all the uniﬁed interactions vary[25,26,27].Theconstraint imposed on varyingαby the need to bring about uniﬁcation at high energy is likely to be signiﬁcant but the complexities of analysing the simulta-neous variation of all the constants involved in the supersymmetric version ofthe standard model are considerable.At the most basic level we recognise that any time variation in theﬁne structure could be carried by either or both of theelectromagnetic or weak couplings above the electroweak scale.The idea that the charge on the electron,or theﬁne structure constant,mightvary in cosmological time was proposed in1948by Teller,[9],who suggested thatα∝(ln t)−1was implied by Dirac’s proposal that G∝t−1and the numerical coincidence thatα−1∼ln(hc/Gm2pr),where m pr is the proton ter,in 1967,Gamow[28]suggestedα∝t as an alternative to Dirac’s time-variationof the gravitation constant,G,as a solution of the large numbers coincidences problem and in1963Stanyukovich had also considered varyingα,[29],in this context.However,this power-law variation in the recent geological past was soon ruled out by other evidence[30].There are a number of possible theories allowing for the variation of theﬁne structure constant,α.In the simplest cases one takes c and to be con-stants and attributes variations inαto changes in e or the permittivity of free space(see[31]for a discussion of the meaning of this choice).This is done by letting e take on the value of a real scalarﬁeld which varies in space and time(for more complicated cases,resorting to complexﬁelds undergoing spon-taneous symmetry breaking,see the case of fast tracks discussed in[32]).Thus e0→e=e0ǫ(xµ),whereǫis a dimensionless scalarﬁeld and e0is a constant denoting the present value of e.This operation implies that some well estab-lished assumptions,like charge conservation,must give way[33].Nevertheless, the principles of local gauge invariance and causality are maintained,as is the scale invariance of theǫﬁeld(under a suitable choice of dynamics).In addition there is no conﬂict with local Lorentz invariance or covariance.With this set up in mind,the dynamics of our theory is then constructed asfollows.Since e is the electromagnetic coupling,theǫﬁeld couples to the gauge ﬁeld asǫAµin the Lagrangian and the gauge transformation which leaves the action invariant isǫAµ→ǫAµ+χ,µ,rather than the usual Aµ→Aµ+χ,µ.The gauge-invariant electromagneticﬁeld tensor is thereforeFµν=1−gFµνFµν.(19) and the dynamics of theǫﬁeld are controlled by the kinetic termSǫ=−1l2 d4x√ǫ2,(20) 7as in dilaton theories.Here,l is the characteristic length scale of the theory, introduced for dimensional reasons.This constant length scale gives the scale down to which the electricﬁeld around a point charge is accurately Coulombic. The corresponding energy scale, c/l,has to lie between a few tens of MeV and Planck scale,∼1019GeV to avoid conﬂict with experiment.Our generalisation of the scalar theory proposed by Bekenstein[19]described in ref.[22,21,20,24]includes the gravitational eﬀects ofψand gives theﬁeld equations:Gµν=8πG T matterµν+Tψµν+T emµνe−2ψ .(21) The stress tensor of theψﬁeld is derived from the lagrangian Lψ=−ωe−2ψL em(22)ωwhere we have deﬁned the coupling constantω=(c)/l2.This constant is of order∼1if,as in[?],the energy scale is similar to Planck scale.It is clear that L em vanishes for a sea of pure radiation since then L em=(E2−B2)/2= 0.We therefore expect the variation inαto be driven by electrostatic and magnetostatic energy-components rather than electromagnetic radiation.In order to make quantitative predictions we need to know how much of the non-relativistic matter contributes to the RHS of Eqn.(22).This is parametrised byζ≡L em/ρ,whereρis the energy density,and for baryonic matter L em= E2/2.For protons and neutronsζp andζn can be estimated from the electro-magnetic corrections to the nucleon mass,0.63MeV and−0.13MeV,respec-tively[42].This correction contains the E2/2contribution(always positive), but also terms of the form jµaµ(where jµis the quarks’current)and so cannot be used directly.Hence we take a guiding valueζp≈ζn∼10−4.Furthermore the cosmological value ofζ(denotedζm)has to be weighted by the fraction of matter that is non-baryonic,a point ignored in the literature[19].Hence,ζm depends strongly on the nature of the dark matter and can take both positive and negative values depending on which of Coulomb-energy or magnetostatic energy dominates the dark matter of the Universe.It could be thatζCDM≈−1 (superconducting cosmic strings,for which L em≈−B2/2),orζCDM≪1(neu-trinos).BBN predicts an approximate value for the baryon density ofΩB≈0.03 with a Hubble parameter of h0≈0.6,implyingΩCDM≈0.3.Thus depending on the nature of the dark matterζm can be virtually anything between−1and +1.The uncertainties in the underlying quark physics and especially the con-stituents of the dark matter make it diﬃcult to impose more certain bounds on ζm.We should not confuse this theory with other similar variations.Bekenstein’s theory does not take into account the stress energy tensor of the dielectricﬁeld in Einstein’s equations,and their application to cosmology.Dilaton theories predict a global coupling between the scalar and all other matterﬁelds.As a result they predict variations in other constants of nature,and also a diﬀerent dynamics to all the matter coupled to electromagnetism.An interesting appli-8cation of our approach has also recently been made to braneworld cosmology in [34].3.1The cosmological equationsAssuming a homogeneous and isotropic Friedmann metric with expansion scale factor a(t)and curvature parameter k in eqn.(21),we obtain theﬁeld equations (c≡1)˙a3 ρm(1+ζm exp[−2ψ])+ρr exp[−2ψ]+ωa2+Λωexp[−2ψ]ζmρm,(24)where H≡˙a/a is the Hubble expansion rate.We can rewrite this more simply as(˙ψa3˙)=N exp[−2ψ](25) where N is a positive constant deﬁned byN=−2ζmρm a3matched approximations.We shall consider the form of the solutions to these equations when the universe is successively dominated by the kinetic energy of the scalarﬁeldψ,pressure-free matter,radiation,negative spatial curvature, and positive cosmological constant.Our analytic expressions are checked by numerical solutions of(23)and(24).3.2Observational implicationsThere are a number of conclusions that can be drawn from the study of the simple BSBM models withζm<0.These models give a goodﬁt to the varying αimplied by the QSO data of refs.[2,3].There is just a single parameter to ﬁt and this is given by the choice−ζmﬁxed to the value given in eq.(29)using a bestﬁt of the theories cosmological model to the QSO observations of refs.[2,3].Other predictions of such WEP violations have also been made in refs.[41,42,43,44].The observational upper bound on this parameter is just an order of magnitude larger,at10−12, but space-based tests planned for the STEP mission are expected to achieve a sensitivity of order10−18and will provide a completely independent check on theories of time-varying e andα.This is an exciting prospect for the future. 3.3The nature of the Friedmann solutionsThe cosmological behaviour of the solutions to these equations was studied by us in detail,both analytically and numerically in refs.[22,21,20,24], [35].Typically,the variation inαdoes not have a signiﬁcant eﬀect on the evolution of the scale factor at late times although the cosmological expansion does signiﬁcantly aﬀect the evolution ofα.The evolution ofαis summarised as follows:During the radiation era a(t)∼t1/2andαis constant in universes with our entropy per baryon and present value ofαlike our own.It increases in the dust era,where a(t)∼t2/3.The increase inαhowever,is very slow with a late-time solution forψproportional to1This type of behaviour can also be found in the presence of time-varying G.If a BD dust universe is exactlyﬂat(k=0)then G will continue to fall forever.Only if there is negative curvature will the evolution of G eventually be turned oﬀand the expansion asymptote to the Milne behaviour with a=t and G→constant.Again,without the small deviation fromﬂatness the strength of gravity would ultimately become too weak for the existence of stars and planets and the universe would become biologically inhospitable,if not uninhabitable.There have been several studies,following Carter,[46]and Tryon[47],of the need for life-supporting universes to expand close to the’ﬂat’Einstein de Sitter trajectory for long periods of time.This ensures that the universe cannot collapse back to high density before galaxies,stars,and biochemical elements can form by gravitational instability,or expand too fast for stars and galaxies to form by gravitational instability[48,7].Likewise,it was pointed out by Barrow and Tipler,[7]that there are similar anthropic restrictions on the magnitude of any cosmological constant,Λ.If it is too large in magnitude it will either precipitate premature collapse back to high density(ifΛ<0)or prevent the gravitational condensation of any stars and galaxies(ifΛ>0).Thus existing studies provide anthropic reasons why we can expect to live in an old universe that is neither too far fromﬂatness nor dominated by a much stronger cosmological constant than observed(|Λ|≤10|Λobs|).Inﬂationary universe models provide a possible theoretical explanation for proximity toﬂatness but no explanation for the smallness of the cosmologi-cal constant.Varying speed of light theories[49,31,50,51,52]oﬀer possible explanations for proximity toﬂatness and smallness of a classical cosmologi-cal constant(but not necessarily for one induced by vacuum corrections in the early universe).We have shown that if we enlarge our cosmological theory to accommodate variations in some traditional constants then it appears to be an-thropically disadvantageous for a universe to lie too close toﬂatness or for the cosmological constant to be too close to zero.This conclusion arises because of the coupling between time-variations in constants likeαand the curvature or Λ,which control the expansion of the universe.The onset of a period ofΛor curvature domination has the property of dynamically stabilising the constants, thereby creating favourable conditions for the emergence of structures.This point has been missed in previous studies because they have never combined the issues ofΛandﬂatness and the issue of the values of constants.By coupling these two types of anthropic considerations weﬁnd that too small a value ofΛor the spatial curvature can be as poisonous for life as too much.Universes like those described above,with increasingα(t),lead inexorably to an epoch where αis too large for the existence of atoms,molecules,and stars to be possible.Surprisingly,there has been almost no consideration of habitability in cos-mologies with time-varying constants since Haldane’s discussions[5]of the bio-logical consequences of Milne’s bimetric theory of gravity.Since then,attention has focussed upon the consequences of universes in which the constants are dif-ferent but still constant.Those cosmologies with varying constants that have been studied have not considered the eﬀects of curvature orΛdomination on the variation of constants and have generally considered power-law variation to12hold for all times.The examples described here show that this restriction has prevented a full appreciation of the coupling between the expansion dynamics of the universe and the values of the constants that deﬁne the course of local physical processes within it.Our discussion of a theory with varyingαshows for theﬁrst time a possible reason why the3-curvature of universes and the value of any cosmological constant may need to be bounded below in order that the universe permit atomic life to exist for a signiﬁcant period.Previous an-thropic arguments have shown that the spatial curvature of the universe and the value of the cosmological constant must be bounded above in order for life-supporting environments(stars)to develop.We note that the lower bounds discussed here are more fundamental than these upper bounds because they de-rive from changes inαwhich have direct consequences for biochemistry whereas the upper bounds just constrain the formation of astrophysical environments by gravitational instability.Taken together,these arguments suggest that within an ensemble of all possible worlds whereαand G are time variables,there might only be aﬁnite interval of non-zero values of the curvature and cosmological constant contributions to the dynamics that both allow galaxies and stars to form and their biochemical products to persist.3.4The role of inhomogeneitiesWe can also detect where and how we might expect spatial variations to arise in a fuller description.Aside from the complexities of the full inhomogeneous cosmological solution for the formation of galaxies,stars,and planets,we can isolate non-uniformities that enter through the constant parameter N which dictates the form and time-evolution of a(t)andα(t).First we see that N is proportional to the density of electromagnetically charged matter in the uni-verse.This will possess some spatial variation and is of order10−5on large scales.More signiﬁcant though is the variation of the baryonic content of the CDM density with scale.We need the CDM to be dominated by matter with magnetic charge(but see Bekenstein).This can be the case on large scale but we know that the dark matter becomes dominated by baryons(therefore with ζ>0)locally.Hence,there is expected to be a very signiﬁcant spatial variation ofζwith scale,including a change of sign,which will feed into the variation of α.3.5General properties of the evolution of alpha and G The evolution equation forψ(t)has a number of simple but important proper-ties.Since N>0the right-hand side or eq.(25)must be positive.This means that linearisations of this equation are dangerous and give rise to linearisation instabilities unless attention is conﬁned to the regimeψ<<1.In general the positivity property means that there can be no oscillations ofψorαin time in solutions of this equation.This follows from the required positivity of(˙ψa3˙),13which means thatψcannot have a maximum.The possible cosmological evolu-tions forψandαare decrease to a minimum followed by a monotonic increase, monotonic decrease,or monotonic increase.This conclusion holds independently of the value of k in the Friedmann equation.This has one very important con-sequence.It means that the asymptotic monotonic non-decrease ofαfound in ourﬂat and open universes will still occur in closed universes.There cannot be a sudden change in the evolution ofαwhen the universe starts to collapse. This also means that if we model spherical overdensities by closed universes embedded in aﬂat background then the evolution ofα(t)in the overdensities will be very similar to that in theﬂat background even when the overdensities collapse to form bound’clusters’.This has the important implication that such an inhomogeneous universe will not end up with very diﬀerent values ofαand ˙αin inside and outside the bound inhomogeneities.This argument can also be applied to the evolution ofφand G in BD theory. Consider the case of dust(p=0).The combination(˙φa3˙)must now be positive and soφcannot have a maximum and G cannot have a minimum regardless of the sign of the curvature parameter k.In particular,G(t)cannot oscillate. Again,this property acts as a safeguard on the divergent evolution of G inside and outside overdensities.4The Second LawThere has been considerable recent discussion[53,54]about the equivalence of models of the variation of diﬀerent dimensional’constants’of Nature.In particular,it has been suggested that consideration of the second law of black hole thermodynamics distinguishes,say,variations of e from variations of c and that some of these variations could be ruled out because they bring about a decrease in time of the Bekenstein-Hawking entropy of a charged black hole. Others have argued that no such distinction is operationally possible.However, we believe that the most crucial factor has been missed in this discussion.In theories which generalise general relativity by allowing traditional constants (like G or e)to vary the black hole solutions with event horizons are particular solutions of the theory in which the constant concerned is a constant.When the constant varies the black hole solution no longer exists and there is no longer any black hole thermodynamics to constrain the variation.The situation is very clear in the simple case of a Schwarzschild black hole in Brans Dicke theory.We know from the work of Hawking[55]that the black hole solutions are the same as those in general relativity.Thus Schwarzschild is aφ˜G−1=constant solution of the Brans-Dickeﬁeld equations.The entropy of this black hole isS bh˜GM2.If we were to apply the second law to this formula it would appear to say that all cosmological solutions in which G falls with time are ruled out.However,this would not be a correct deduction(which is fortunate because we see from eq.(10)that essentially all Brans-Dicke cosmologies have such behaviour)because14φand G are constant on the Schwarzschild horizon.If we allow variation of G then the solution turns into a naked singularity and the thermodynamic relations no longer exist.Thus one cannot at present use considerations of black hole thermodynamics to constrain or distinguish the time or space variation of constants of Nature by simply’writing in’time variations into the formulae that deﬁne the black hole when these constants do not vary.Acknowledgements I would like to thank my collaborators Jo˜a o Magueijo, H˚avard Sandvik,John Webb,Michael Murphy and David Mota for their essen-tial contributions to the work described here.I would also like to thanks Bruce Bassett,Thibault Damour,Paul Davies,Tamara Davies,Carlos Martins,John Moﬀat and Cliﬀord Will for discussions.References[1]J.D.Barrow,The Constants of Nature:from alpha to omega,JonathanCape,London(2002).[2]M.Murphy,J.Webb,V.Flambaum,V.Dzuba,C.Churchill,J.Prochaska,A.Wolfe,MNRAS,327,1208(2001)[3]J.K.Webb,V.V.Flambaum,C.W.Churchill,M.J.Drinkwater J.D.Bar-row,Phys.Rev.Lett.82,884(1999);J.K.Webb,M.T.Murphy,V.V.Flambaum,V.A.Dzuba,J.D.Barrow,C.W.Churchill,J.X.Prochaska,A.M.Wolfe,Phys.Rev.Lett.87,091301(2001).[4]ne,Relativity,Gravitation and World Structure,Clarendon,Ox-ford,(1935).[5]J.B.S.Haldane,Nature139,1002(1937)and158,555(1944)and article inNew Biology,No.16,eds.M.L.Johnson et al,Penguin,London(1955).[6]H.Weyl,Ann.Physik59,129(1919).[7]J.D.Barrow and F.J.Tipler,The Anthropic Cosmological Principle,OxfordUP,Oxford(1986).[8]P.A.M.Dirac,Nature139,323(1937).[9]E.Teller,Phys.Rev.73,801(1948).[10]R.H.Dicke,Rev.Mod.Phys.29,355(1957)and Nature192,440(1961).[11]C.Brans and R.H.Dicke,Phys.Rev.124,924(1961).[12]J.D.Barrow,Mon.Not.R.astr.Soc.,282,1397(1996).[13]J.D.Barrow,in Proc.Erice Summer School Current Topics in Astrofunda-mental Physics:Primordial Cosmology,pp.269-305,ed.N.Sanchez(1997), gr-qc/9711084.15。

tpo36三篇托福阅读TOEFL原文译文题目答案译文背景知识

tpo36三篇托福阅读TOEFL原文译文题目答案译文背景知识阅读-1 (2)原文 (2)译文 (3)题目 (5)答案 (10)背景知识 (11)阅读-2 (12)原文 (12)译文 (14)题目 (15)答案 (20)背景知识 (20)阅读-3 (24)原文 (24)译文 (25)题目 (27)答案 (32)背景知识 (33)阅读-1原文Soil Formation①Living organisms play an essential role in soil formation. The numerous plants and animals living in the soil release minerals from the parent material from which soil is formed, supply organic matter, aid in the translocation (movement) and aeration of the soil, and help protect the soil from erosion. The types of organisms growing or living in the soil greatly influence the soil's physical and chemical characteristics. In fact, for mature soils in many parts of the world, the predominant type of natural vegetation is considered the most important direct influence on soil characteristics. For this reason, a soil scientist can tell a great deal about the attributes of the soil in any given area simply from knowing what kind of flora the soil supports. Thus prairies and tundra regions, which have characteristic vegetations, also have characteristic soils.②The quantity and total weight of soil flora generally exceed that of soil fauna. By far the most numerous and smallest of the plants living in soil are bacteria. Under favorable conditions, a million or more of these tiny, single-celled plants can inhabit each cubic centimeter of soil. It is the bacteria, more than any other organisms, that enable rock or other parent material to undergo the gradual transformation to soil. Some bacteria produce organic acids that directly attack parent material, breaking it down and releasing plant nutrients. Others decompose organic litter (debris) to form humus (nutrient-rich organic matter). A third group of bacteria inhabits the root systems of plants called legumes. These include many important agricultural crops, such as alfalfa, clover, soybeans, peas, and peanuts. The bacteria that legumes host within their root nodules (small swellings on the root) change nitrogen gas from the atmosphere into nitrogen compounds that plants are able to metabolize, a process, known as nitrogen fixation, that makes the soil more fertile. Other microscopic plants also are important in soil development. For example, in highly acidic soils where few bacteria can survive, fungi frequently become the chief decomposers of organic matter.③More complex forms of vegetation play several vital roles with respect to the soil. Trees, grass, and other large plants supply the bulk of the soil's humus. The minerals released as these plants decompose on the surface constitute an important nutrient source for succeeding generations of plants as well as for other soil organisms. In addition, trees can extend their roots deep within the soil and bring up nutrients from far below the surface. These nutrients eventually enrich the surface soil when the tree drops its leaves or when it dies and decomposes. Finally, trees perform the vital function of slowing water runoff and holding the soil in place with their root systems, thus combating erosion. The increased erosion that often accompanies agricultural use of sloping land is principally caused by the removal of its protective cover of natural vegetation.④Animals also influence soil composition. The faunal counterparts of bacteria are protozoa. These single-celled organisms are the most numerous representatives of the animal kingdom, and, like bacteria, a million or more can sometimes inhabit each cubic centimeter of soil. Protozoa feed on organic matter and hasten its decomposition. Among other soil-dwelling animals, the earthworm is probably the most important. Under exceptionally favorable conditions, up to a million earthworms (with a total body weight exceeding 450 kilograms) may inhabit an acre of soil. Earthworms ingest large quantities of soil, chemically alter it, and excrete it as organic matter called casts. The casts form a high-quality natural fertilizer. In addition, earthworms mix of soil both vertically and horizontally, improving aeration and drainage.⑤Insects such as ants and termites also can be exceedingly numerous under favorable climatic and soil conditions. In addition, mammals such as moles, field mice, gophers, and prairie dogs sometimes are present in sufficient numbers to have significant impact on the soil. These animals primarily work the soil mechanically. As a result, the soil is aerated broken up, fertilized, and brought to the surface, hastening soil development.译文土壤形成①活生物体在土壤形成中起着重要作用。

医护英语考试试题及答案

医护英语考试试题及答案一、选择题（每题2分，共20分）1. What does the abbreviation "ICU" stand for?A. International Communication UnitB. Intensive Care UnitC. International Clinical UnitD. Inpatient Care Unit2. Which of the following is a common medical instrument?A. StethoscopeB. MicrophoneC. ThermometerD. All of the above3. What is the medical term for a condition where blood pressure is abnormally low?A. HypertensionB. HypotensionC. HyperglycemiaD. Hypoglycemia4. Which of the following is not a type of medical imaging?A. X-rayB. MRIC. CT scanD. Ultrasound5. What does "CPR" stand for in medical terms?A. Cardiopulmonary ResuscitationB. Chronic Pain ReliefC. Clinical Pathology ReportD. Continuous Positive Respiration6. What is the meaning of the term "anemia"?A. A condition characterized by high levels of red blood cellsB. A condition characterized by low levels of red blood cellsC. A condition characterized by high levels of white blood cellsD. A condition characterized by low levels of white blood cells7. Which of the following is a measure to prevent infectionin a hospital setting?A. Hand hygieneB. Smoking indoorsC. Sharing needlesD. None of the above8. What is the medical term for a surgical procedure to remove a tumor?A. AmputationB. AppendectomyC. ExcisionD. Incision9. Which of the following is a common symptom of the flu?A. Dry coughB. InsomniaC. HyperactivityD. Loss of appetite10. What does "HIV" stand for?A. Hepatitis Infection VirusB. Human Immunodeficiency VirusC. High Intensity VirusD. Hormone Infection Virus二、填空题（每题1分，共10分）11. A healthcare professional who specializes in surgery is called a _______.12. The process of cleaning a wound is known as _______.13. The abbreviation "BP" is commonly used to refer to_______.14. A person with a medical condition that requires ongoing treatment is referred to as a _______.15. The medical term for a broken bone is _______.16. The first step in treating a burn is to _______ the area.17. The abbreviation "OT" stands for _______.18. Aspirin is often used as an _______ for pain relief.19. The medical term for a severe allergic reaction is_______.20. The abbreviation "A&E" refers to the _______ departmentin a hospital.三、简答题（每题5分，共30分）21. Explain the purpose of a blood transfusion.22. Describe the role of a nurse in a hospital setting.23. What are the signs of a heart attack?24. Discuss the importance of patient confidentiality in healthcare.四、阅读理解（每题5分，共20分）阅读以下短文，回答下列问题。

219316061_基于主成分分析的大蒜药用质量评价

胡小霞，邓丽娟，刘睿婷，等. 基于主成分分析的大蒜药用质量评价[J]. 食品工业科技，2023，44（12）：293−299. doi:10.13386/j.issn1002-0306.2022080237HU Xiaoxia, DENG Lijuan, LIU Ruiting, et al. Evaluation of Medicinal Quality of Garlic Based on Principal Component Analysis[J].Science and Technology of Food Industry, 2023, 44(12): 293−299. (in Chinese with English abstract). doi: 10.13386/j.issn1002-0306.2022080237· 分析检测 ·基于主成分分析的大蒜药用质量评价胡小霞1，邓丽娟2，刘睿婷3,4，史荣梅3,5,*（1.乌鲁木齐海关技术中心，新疆乌鲁木齐 830063；2.天康生物制药有限公司，新疆乌鲁木齐 830026；3.新疆医科大学药学院，新疆乌鲁木齐 830011；4.新疆胡蒜研究院（有限公司），新疆乌鲁木齐 830013；5.新疆大蒜药用研究重点实验室，新疆乌鲁木齐 830013）摘　要：通过比较分析大蒜的药用品质，建立大蒜药用质量评价体系。

以水分、灰分、水溶性浸出物、大蒜素含量、蒜氨酸含量、大蒜辣素含量和蒜酶活力为指标，分析甘肃民乐、江苏邳州、山东金乡、河南郑州、重庆巫溪和新疆且末、拜城、种马场、虎头镇、大有镇、新地乡等11个产地大蒜的药用品质特征及差异，并通过相关性分析、主成分分析和聚类分析对大蒜质量进行综合评价。

结果表明，不同产地大蒜的上述指标都具有显著性差异。

相关性分析表明，蒜酶活力与水分呈极显著正相关性（P <0.01），蒜氨酸含量与灰分和大蒜辣素含量呈显著正相关性（P <0.05）。

低频活动漂浮潜水船声探测系统（LFATS）说明书

LOW-FREQUENCY ACTIVE TOWED SONAR (LFATS)LFATS is a full-feature, long-range,low-frequency variable depth sonarDeveloped for active sonar operation against modern dieselelectric submarines, LFATS has demonstrated consistent detection performance in shallow and deep water. LFATS also provides a passive mode and includes a full set of passive tools and features.COMPACT SIZELFATS is a small, lightweight, air-transportable, ruggedized system designed specifically for easy installation on small vessels. CONFIGURABLELFATS can operate in a stand-alone configuration or be easily integrated into the ship’s combat system.TACTICAL BISTATIC AND MULTISTATIC CAPABILITYA robust infrastructure permits interoperability with the HELRAS helicopter dipping sonar and all key sonobuoys.HIGHLY MANEUVERABLEOwn-ship noise reduction processing algorithms, coupled with compact twin line receivers, enable short-scope towing for efficient maneuvering, fast deployment and unencumbered operation in shallow water.COMPACT WINCH AND HANDLING SYSTEMAn ultrastable structure assures safe, reliable operation in heavy seas and permits manual or console-controlled deployment, retrieval and depth-keeping. FULL 360° COVERAGEA dual parallel array configuration and advanced signal processing achieve instantaneous, unambiguous left/right target discrimination.SPACE-SAVING TRANSMITTERTOW-BODY CONFIGURATIONInnovative technology achievesomnidirectional, large aperture acousticperformance in a compact, sleek tow-body assembly.REVERBERATION SUPRESSIONThe unique transmitter design enablesforward, aft, port and starboarddirectional transmission. This capabilitydiverts energy concentration away fromshorelines and landmasses, minimizingreverb and optimizing target detection.SONAR PERFORMANCE PREDICTIONA key ingredient to mission planning,LFATS computes and displays systemdetection capability based on modeled ormeasured environmental data.Key Features>Wide-area search>Target detection, localization andclassification>T racking and attack>Embedded trainingSonar Processing>Active processing: State-of-the-art signal processing offers acomprehensive range of single- andmulti-pulse, FM and CW processingfor detection and tracking. Targetdetection, localization andclassification>P assive processing: LFATS featuresfull 100-to-2,000 Hz continuouswideband coverage. Broadband,DEMON and narrowband analyzers,torpedo alert and extendedtracking functions constitute asuite of passive tools to track andanalyze targets.>Playback mode: Playback isseamlessly integrated intopassive and active operation,enabling postanalysis of pre-recorded mission data and is a keycomponent to operator training.>Built-in test: Power-up, continuousbackground and operator-initiatedtest modes combine to boostsystem availability and accelerateoperational readiness.UNIQUE EXTENSION/RETRACTIONMECHANISM TRANSFORMS COMPACTTOW-BODY CONFIGURATION TO ALARGE-APERTURE MULTIDIRECTIONALTRANSMITTERDISPLAYS AND OPERATOR INTERFACES>State-of-the-art workstation-based operator machineinterface: Trackball, point-and-click control, pull-down menu function and parameter selection allows easy access to key information. >Displays: A strategic balance of multifunction displays,built on a modern OpenGL framework, offer flexible search, classification and geographic formats. Ground-stabilized, high-resolution color monitors capture details in the real-time processed sonar data. > B uilt-in operator aids: To simplify operation, LFATS provides recommended mode/parameter settings, automated range-of-day estimation and data history recall. >COTS hardware: LFATS incorporates a modular, expandable open architecture to accommodate future technology.L3Harrissellsht_LFATS© 2022 L3Harris Technologies, Inc. | 09/2022NON-EXPORT CONTROLLED - These item(s)/data have been reviewed in accordance with the InternationalTraffic in Arms Regulations (ITAR), 22 CFR part 120.33, and the Export Administration Regulations (EAR), 15 CFR 734(3)(b)(3), and may be released without export restrictions.L3Harris Technologies is an agile global aerospace and defense technology innovator, delivering end-to-endsolutions that meet customers’ mission-critical needs. The company provides advanced defense and commercial technologies across air, land, sea, space and cyber domains.t 818 367 0111 | f 818 364 2491 *******************WINCH AND HANDLINGSYSTEMSHIP ELECTRONICSTOWED SUBSYSTEMSONAR OPERATORCONSOLETRANSMIT POWERAMPLIFIER 1025 W. NASA Boulevard Melbourne, FL 32919SPECIFICATIONSOperating Modes Active, passive, test, playback, multi-staticSource Level 219 dB Omnidirectional, 222 dB Sector Steered Projector Elements 16 in 4 stavesTransmission Omnidirectional or by sector Operating Depth 15-to-300 m Survival Speed 30 knotsSize Winch & Handling Subsystem:180 in. x 138 in. x 84 in.(4.5 m x 3.5 m x 2.2 m)Sonar Operator Console:60 in. x 26 in. x 68 in.(1.52 m x 0.66 m x 1.73 m)Transmit Power Amplifier:42 in. x 28 in. x 68 in.(1.07 m x 0.71 m x 1.73 m)Weight Winch & Handling: 3,954 kg (8,717 lb.)Towed Subsystem: 678 kg (1,495 lb.)Ship Electronics: 928 kg (2,045 lb.)Platforms Frigates, corvettes, small patrol boats Receive ArrayConfiguration: Twin-lineNumber of channels: 48 per lineLength: 26.5 m (86.9 ft.)Array directivity: >18 dB @ 1,380 HzLFATS PROCESSINGActiveActive Band 1,200-to-1,00 HzProcessing CW, FM, wavetrain, multi-pulse matched filtering Pulse Lengths Range-dependent, .039 to 10 sec. max.FM Bandwidth 50, 100 and 300 HzTracking 20 auto and operator-initiated Displays PPI, bearing range, Doppler range, FM A-scan, geographic overlayRange Scale5, 10, 20, 40, and 80 kyd PassivePassive Band Continuous 100-to-2,000 HzProcessing Broadband, narrowband, ALI, DEMON and tracking Displays BTR, BFI, NALI, DEMON and LOFAR Tracking 20 auto and operator-initiatedCommonOwn-ship noise reduction, doppler nullification, directional audio。

2024年高考英语阅读练习10篇(外刊精选)

高中英语外刊阅读语篇精选20篇阅读理解(1)本篇源自：Woodland Park ZooAbout the programFor individuals aged 16 years and older.Volunteers are ambassadors for Woodland Park Zoo and an important part of our zoo team. We seek individuals who are excited about engaging in thez00's mission to save wildlife and inspire everyone to make conservation a priority in their lives.The primary focus of our volunteers is engaging with zoo guests by offering assistance and information, facilitating extraordinary zoo experiences and helping at a variety of special events. Once in the program, volunteers also have the opportunity to apply and interview for positions in other aspects of the zoo's operations including horticulture, education and leadership roles within the Volunteer Program RequirementsOur program offers all volunteers opportunities to continuously learn more about conservation and animals, and to make an impact every day through this active role in the zoo community.Volunteer program requirementsThe Woodland Park Zoo Volunteer Program requires interested individuals to:Be at least 16 years old;Demonstrate commitment to the highest standards of customer service;Have enthusiasm for people, animals and conservation;Commit to the Volunteer Program for a minimum of one year;Meet the minimum service requirement of six hours per month;Attend one Volunteer Program information session;Successfully complete zoo ambassador training;Pay a one-time S 30 program fee to cover costs upon entry into the program(there is no fee to apply; financial assistance is available);Provide proof of full vaccination against COVID-19 if accepted into zoo ambassador training;People are considered fully vaccinated two weeks after their second dose in atwo-dose series or two weeks after a single-dose vaccine. Volunteer placement offers may be withdrawn for individuals who do not comply with this policy.( B )1.What is a volunteer expected to do?A. Organize a variety of special events.B. Improve zoo guests' visiting experiences.C. Assist in academic research and collect data.D. Create opportunities to interview zoo guests.( A )2. Who might be a qualified volunteer?A. A senior with sufficient time and enthusiasm.B. A primary school student devoted to customer service.C. An experienced, committed, and unvaccinated college student.D. A retired biology professor signing up for the zoo ambassador training.( B )3. Where is this text probably taken from?A. An advertisement.B.A website article.C. An academic essay.D. A scientific journal.阅读理解(2)本篇源自：The Los Angeles TimesThe summer isn't even halfway through and it's already proved to be a season of deadly extremes.In a little over a month, four major heatwaves have broiled the Western United States,including record-breaking triple-digit temperatures in Oregon and Washington that caused hundreds of heat-related deaths.Wildfires are again tearing through the West, burning hundreds of thousands of acres in California, Oregon and British Columbia in Canada. The fires are so massive that smoke has traveled all the way to the East Coast, prompting health warnings in Connecticut and Maryland and turning the skies above New York City hazy and red. And from Germany to China, extreme flooding has caused death and destruction. At least180 people in Germany, Belgium and the Netherlands were killed last week when two months' worth of rain fell in two days, causing floods and mudslides. In the central Chinese province of Henan, 14 people died after riders were trapped on a subway amid catastrophic flooding after torrential rains.These terrifying scenes from across the globe have long been predicted by scientists studying our warming planet. Higher temperatures would lead to more heatwaves and droughts in some areas that would fuel bigger, more frequent wildfires. In other areas the warmer climate would trap moisture in the atmosphere, leading to heavier rainfall during storms.Climate change is making normal weather events-heatwaves, droughts, rainstorms and hurricanes more extreme and more devastating to communities unprepared for the attack. What's most frightening, however, is that extremes are happening faster than many predicted. As the last few weeks has shown, there's no time to waste. The summer has already given a terrible glimpse of the future if we don't change course now.( A )1. What does the underlined word “broiled" mean in Paragraph 2?A. Roasted.B.Flooded.C.Burnt.D.Swept.( D )2.How does the author stress the severity of extreme flooding?A. By making comparisons.B. By describing details.C. By analyzing causes.D. By listing numbers.( A )3.The underlined part "These terrifying scenes" in Paragraph 5 refers to①heatwaves ② wildfires ③ extreme flooding ④ tornadoes ⑤ hurricanesA.①②③B.②③④C.①③④D.③④⑤( B )4. What is the purpose of the passage?A. To inform us of extreme weather.B. To call on us to pay more attention to climate change.C. To instruct us how to survive in extreme weather.D. To predict climate change in the future.阅读理解(3)本篇源自：NatureSince first appearing in India in late 2020, the Delta variant of SARS-CoV-2 has become the predominant strain（主要毒株）in much of the world. Researchers might now know why Delta has been so "successful": People infected with it produce far more viruses than those infected with the original version ofSARS-CoV-2,making it very easy to spread.According to current estimates, the Delta variant could be more than twice as transmissible as the original strain ofSARS-CoV-2. To find out why, epidemiologist Jing Lu at the Guangdong Próvincial Center for Disease Control and Prevention in Guangzhou, China, and his colleagues tracked 62 people who were some of the first people in mainland China to become infected with the Delta strain.The team tested study participants' "viral load”-a measure of the density of viral particles in the body-every day throughout the course of infection to see how it changed over time.Researchers then compared participants' infection patterns with those of 63 people who contracted the original SARS-CoV-2 strain in 2020.The researchers report that the virus was first detectable in people with the Delta variant four days after exposure, compared with an average of six days among people with the original strain,suggesting that Delta reproduces much faster. Individuals infected with Delta also had viral loads up to 1,260 times higher than those in people infected with the original strain.The combination of a large number of viruses and a short incubation period makes sense as an explanation for Delta's heightened transmissibility, says epidemiologist BenjamiCowling at the University of Hong Kong. The sheer amount of virus in the respiratory tract means that super spreading events are likely to infect even more people, and that people might begin spreading the virus earlier after they become infected.And the short incubation period makes contact tracing more difficult in countries such as China,which systematically tracks each infected person's contacts and requires them to quarantine.“Putting it all together, Delta's really difficult to stop," Cowling says.( D )1. What is the purpose of epidemiologist Jing Lu's research?A. To find out whether Delta is a variant of SARS-CoV-2.B. To determine how SARS-CoV-2 progresses.C. To find out the solution to ending COVID-19.D. To find out what causes Delta to spread faster.( A )2. How does Jing Lu's team conduct their research?A.By comparing the participants' infection patterns.B. By monitoring the participants' course of infection.C. By measuring the participants' exposure time to Delta.D. By analyzing the data collected from previous studies.( D )3.Which of the following does NOT make for the fast spread of Delta?A. Delta's high viral loads.B. Delta's rapid reproduction ability.C. Delta's short incubation period.D. Delta's ability to escape the immune system.( D )4.What is Cowling's attitude toward stopping Delta?A.Indifferent.B. Ambiguous.C. Optimistic.D. Cautious.阅读理解(4)本篇源自：The EconomistA toothpaste tube, squeezed and twisted out of shape in a vain attempt to extract its remaining contents, haunts many a bathroom. But not, perhaps, for much longer. Colgate-Palmolive,an American consumer-goods giant, has taken up an invention by a pair of experts in supper-slippery surfaces to produce toothpaste tubes that promise to deliver every last scrap of their contents.In 2012 Kripa Varanasi, a professor at the Massachusetts Institute of Technology, and DaveSmith,his PhD student, set up a company called LiquiGlide to commercialize their work on making liquids flow more easily through pipes and out of containers. What caught many people's imagination at the time was a demonstration of how this could be used to empty a ketchup bottle without shaking it violently.The new toothpaste, called Elixir, comes in three varieties: a formula for whitening teeth,one for gum and enamel（牙龈和牙釉质）care and a “detox” version which，it is claimed，removes impurities from the mouth. All are packaged in plastic tubes that can be emptied with ease. Elixir has gone on sale in Europe, though no decision has yet been made about whether it will be sold elsewhere.To produce their slippery pipes and containers, Professor Varanasi and Dr. Smith first impose a microscopically textured pattern on them and then apply a suitably formulated liquid. This fills the gaps in the texture, creating a surface across which gooey substances slide easily. Any risk of contamination（污染）can be eliminated by making the liquid in question from materials also employed in the product.Besides pleasing customers who like to get their money's worth, the new,slippery toothpaste tubes should help with recycling. Existing tubes are rarely recycled, not only because they have residue left inside them but also because they are usuallymade from a laminate of plastic and aluminum foil. Mixed materials of this sort are hard to recycle, and therefore end up being dumped in landfills. Despite their success with toothpaste tubes, Professor Varanasi and Dr.Smith have not given up on food containers.( D )1.What is special about the new toothpaste tube?A.Its twisted shape.B.Its delivery service.C. Its remaining contents.D.Its slippery pipes and containers.( D )2. What does the underlined word “this” in Paragraph 2 mean?unching their products onto the market.B. Setting up LiquiGlide to take up an invention.C. Squeezing and shaking a toothpaste tube.D. Making liquids slide easily on slippery surfaces.( B )3.What can be inferred from the passage?A. The new toothpaste will be sold around the world soon.B. A suitably formulated liquid is vital in producing the slippery pipes.C. Existing tubes are easy to recycle, but hard to empty.D. Professor Varanasi and Dr. Smith find it impossible to apply the invention to food containers.阅读理解(5)本篇源自：Science NewsA new chemical analysis has revealed an ugly truth about beauty products: Many beauty products may contain highly persistent, potentially harmful “forever chemicals” called PFAS.PFAS，short for per-and polyfluoroalkyl substances（多氟烷基化合物），include thousands of chemicals that are so sturdy that they can stay in the body for years and the environment for centuries. Those compounds have been linked to high cholesterol,thyroid diseases and other problems. “There is no known good PFAS,” says chemist and physicist Graham Peaslee of the University of Notre Dame in Indiana.In the first large screening of makeup for PFAS in the United States and Canada, Peasleeand colleagues found that 52 percent of over 200 tested products had high fluorine（氟）concentrations，suggesting the presence of PFAS. The researchers report online on June 15 in Environmental Science & Technology Letters.The potential health risks of PFAS in makeup are not yet clear, Peaslee says. But besides people ingesting or absorbing PFAS when wearing makeup, makeup washed down could get into drinking water.Peaslee's team measured the amount of fluorine, a key component of PFAS, in 231 cosmetics.63 percent of foundations，55 percent of lip products and 82 percent of waterproof mascara（睫毛膏）contained high leveIs of fluorine. Long-lasting or waterproof products were especially likely to contain lots of fluorine. That makes sense,since PFAS are water-resistant.In addition to posing their own potential health risks, these compounds can break down in the body into other PFAS, such as perfluorooctanoic acid, which has been linked to cancers and low birth weights.( A)1.The underlined word “sturdy” in Paragraph 2 probably means“_”.A.stubbornB.harmfulC.beneficialD.flexible( B )2. According to the passage, which of the following statements is TRUE?A. PFAS are the main reason for health problems such as high cholesterol.B. More than 100 tested products are high in fluorine concentrations.C. Scientist have figured out the potential health risks of PFAS.D. PFAS are harmful to health because it can not be broken down.( C )3.Where is this text most likely from?A.A chemistry textbook.B. A cosmetic advertisement.C.A science website.D. A traveling journal.阅读理解(6)本篇源自：The New York TimesIn 1946，a 23-year-old army veteran（退伍军人）named John Goodenough headed to the University of Chicago with a dream of studying physics. When he arrived, a professor warned him that he was already too old to succeed in the field. He ignored the professor's advice and today, at 94, has just got the tech industry excited about his blazing creativity. He and his team at the University of Texas at Austin filed a patent application on a new kind of battery that,if it works as promised, would be so cheap, lightweight, and safe that it would revolutionize electric cars and kill off petroleum-fueled vehicles.We tend to assume that creativity declines with age. On the contrary, there's plenty of evidence to suggest that late blooming is not uncommon. John P. Walsh, one of the professors,joked that the Patent Office should give a “senior discount” because “there's clear evidence that people with seniority are making important contributions to invention". A study of Nobel Physics winners found that, since the 1980s, they have made their discoveries, on average, at age 50.The study also found that the peak of creativity for Nobel winners is getting higher every year.When talking about his late-life success, Dr. Goodenough said, “Some of us are turtles;we crawl and struggle along, and we haven't maybe figured it out by the time we're 30.But the turtles have to keep on walking." This crawl through life can be advantageous, he pointed out,particularly if you wander around through different fields, picking up clues as you go along. Dr.Goodenough started in physics and hopped sideways into chemistry and materials science,while also keeping his eye on the social and political trends that could drive a green economy.“You have to draw ona fair amount of experience in order to be able to put ideas together,” he said. EVERROTIONHe also credits his faith for keeping him focused on his mission to defeat pollution and ditch（摆脱）petroleum（石油）.“I＇m grateful for the doors that have been opened to me indifferent periods of my life,” he said. He believes the glass battery was just another example of the happy accidents that have come his way: “At just the right moment when I was looking for something, it walker into the door.”( B )1.Dr.Goodenough excited people withA.his switching his majorsB. his newly invented batteryC.his obtaining a patentD.his ignoring the professor's warning( C )2. What can we know about John P. Walsh mentioned in Paragraph 2?A.He excels at telling jokes.B.He received a senior discount recently.C.He believes age is not a barrier to creativity.D.He co-invented the battery with Dr. Goodenough.( C )3.What is the purpose of the passage?A.To inform us of a new invention.B. To analyze the advantages of being old.C. To point out age is no barrier to innovation.D.To predict the age of future Nobel Prize winners.阅读理解(7)本篇源自：CricketLong ago，in the unhappy village of Chelm，there lived an old sage（智者）.All the villagers were unhappy because they thought their neighbors had better lives than them. So, day and night, the envious townsfolk would call upon their sage to complain. Before the sage could even raise a spoonful of breakfast to his lips, the baker would burst into his house for a morning's complaint.“They say my bread isn't crispy! Tell me, sage, how I can make crispy bread when all I've got is a hundred-year-old oven that's really an icebox! The emperor's heart is warmer than my oven! And how can I afford a new oven when nobody buys my bread? You see the pickle I'm in? A schoolteacher I should have been. Schoolteachers don't have such headaches.”No sooner had the baker stomped out of the door than the butcher marched in. “My customers do nothing but complain! This chicken's too fat! This meat's too tough! Be a bookkeeper, my dear mother once told me. But did I listen? No. Now look at this pickle I'm in! "And after the butcher complained, the tailor, the shoemaker, and the milkman complained...It was more than a person could stand. Something had to be done. Early one brisk fall morning, the sage marched to the village square, where he posted a huge sign that read: All citizens of Chelm will gather here at noon. Bring a big greenpickle.When everybody arrived, the sage said, “Imagine that everything you are is in your pickle.Your wisdom and your foolishness are in your pickle. Your blessings and your curses are in your pickle. Your talents and your flaws are in your pickle. If you don't like your pickle, no big deal: Pick someone else's. Go ahead and choose."And, with that pronouncement, all the citizens now had the overwhelming task of deciding whose pickle they wanted. The baker's eye immediately fell on the schoolteacher's. The schoolteacher's eye shot over to the tailor's. Every eye examined every pickle in town.To this day, it isn't clear who chose first. Some say the baker, some the milkman, but one thing is absolutely certain: When it was over, the townspeople had taken back their very own pickles.Since that day, whenever a villager approached the sage to complain, though not many of the town folk did, the sage would simply say, “It's your pickle; you picked it, and that would be the end of that."( A )1.What can we infer according to the baker's complaint?A. The oven doesn't function well.B.The townsfolk are too picky.C.He has hurt the emperor's heart.D. Schoolteachers are more welcome.( A )2.Which words can be used to describe the sage?A.Patient and wise.B. Generous and modest.C.Envious and brilliant.D.Impatient and timid.( B )3.Which of the following sayings might the sage agree with?A. Pride hurts, modesty benefits.B. Don't blame destiny, and don't blame the others.C.Behind bad luck comes good luck.D.All that glitters is not gold.( C )4.Which is the best title for the text?A.Turn to a sageB. Decide to be happyC. Pick a pickleD. Choose a career阅读理解(8)本篇源自：Scientific AmericanMindfulness may indeed have psychological benefits. Earlier this year, researches revealed that mindfulness-based interventions had benefits for a number of health outcomes, including stress, anxiety and depression. Although mindfulness has its merits, psychological research has also revealed that in some circumstances it's important to be mindless. Everyday examples range from riding a bike to choppingcucumbers to brushing your teeth.Research has also revealed that paying too much attention to what you're doing can have damaging effects, particularly when you perform well-practiced skills. In fact, this is one reason why some experts appear to “choke under pressure”: They think too much about the mechanics of the task at hand.In a classic study, cognitive scientist Sian Beilock and her colleagues had skilled golfers attempt to sink putts（击球入洞）under different experimental conditions. In one condition，the golfers were simply instructed to pay attention to the swing of their club and say “stop”when they finished their swing. In another condition, they were instructed to listen for a target sound while ignoring other noises and say the word “tone”when they heard the target sound.Counter-intuitively, the skilled golfers performed substantially worse when they focused on their swing than when they paid attention to irrelevant sounds. The effect of paying attention to their swing was so damaging that the golfers actually did better when they were warming up before the experiment began.More recently, psychologist Yannick Balk and his colleagues had golfers try different interventions designed to alleviate the effects of performance pressure. The researchers induced performance pressure by videotaping the participants, telling them that their score sheets would be posted publicly at the clubhouse and encouraging great performance with prizes. Without an intervention, the golfers performed significantly worse under pressure. Yet participants who were encouraged to think about something else-specifically,a song they knew by heart-improved when the stakes were high. It is worth cautioning that these results should be replicated in larger samples and across different contexts.Nevertheless, the important message from this research is that focusing too carefully on the execution of well-practiced motor sequences can cause mistakes. Of course, we should not resign ourselves to going through life on autopilot, missing opportunities t make deeper connections with ourselves, one another and our environment. But there are situations where we should let automaticity take over. The next time you ride a bike, don't overthink it.( B )1. Mindfulness is significant when you are.A. brushing your teethB. suffering from depressionpleting your daily routineD. performing well-practiced skills( C )2. What does the classic study prove?A.What benefits mindlessness can bring.B. How mindlessness works in a competition.C.Whether mindfulness can have damaging effects.D. Why mindfulness can boost athletic performance.( B )3. According to the results of Yannick Balk's study, we'd betterA. be absent-minded in Math classB. listen to the music while joggingC. multitask while learning EnglishD. pay close attention while cutting vegetables阅读理解(9)本篇源自：National Geographic TravelerPick-your-own farms are set for a post-lockdown boom this summer, as people look to support local businesses and spend more time outdoors.Here are four of our favorites.Parkside Farm,EnfieldJuicy blackberries, and strawberries are the stars of the show at this pick-your-own place on the northern edge of London. One key selling point is the “table-top" strawberry-growing system, which means plants are grown in places at waistheight-no more bending down in the dirt to pick your berries. Park side is also one of the few farms accessible without a car,as long as you don't mind a walk-it's 25 minutes from Gordon Hill station.Craigie's Farm, ScotlandJust outside Edinburgh, Craigie's Farm is bursting with produce including cherries, peas,broad beans and, perhaps surprisingly, sunflowers. The onsite shop, deli and cafe have a lot more to offer besides fruit and vegetables-you can pick up homemade jams, meat,cheese and an apple press for making your own juice. There are activities for children too, including a Nature Detective Trail involving encounters with sheep and goats.Hewitts Farm,KentThis family-run farm in Kent offers everything from spinach to apples and blackberries during its pick-your-own season, which runs from June to October(for Halloween pumpkins). There's also a shop selling farm-grown and local produce, as well as free tractor rides for youngsters on Sundays during the summer.Bellis Brothers Farm, WrexhamThis farm in North Wales started growing strawberries back in 1860 and has operated as a pick-your-own since 1967. More fruits have been added since then, but it's still mostly known for its strawberries. Pickers can download Bellis family strawberry recipes from the farm's website,including those for jams and a baked strawberry cheesecake.( B )1.Which place is recommended if visitors want homemade jams?A.Parkside Farm.B. Craigie's Farm.C.Hewitts Farm.D.Bellis Brothers Farm.( B )2. Which of the following is TRUE about Parkside Farm?A. You need not worry about getting dirty on the farm.B. You can pick berries without bending down.C.You must drive there due to its long distance from the station.D. You can enjoy sunflowers in the sunshine.( A )3.In which part of the magazine can you probably find this passage?A.Travel.B.Books.C.Business.D.Sports.阅读理解(10)本篇源自：Entertainment WeeklyBuilding an entire hour around the lives of teenagers was an uncommon choice at the time.But the inexperienced Fox network decided to have a try. And the result was somehow more popular than Brandon Walsh walking down a hallway at West Beverly Hills High School. "Itused to be kid TV, or adult TV with teenage elements to it," says Julie Plec, co-creator of TheVampire Diaries. "My first memory of teen TV was seeing a commercial for Beverly Hills,90210." Nowadays, she continues, "teen TV is important because it's new.”Maintaining that newness is the big challenge for a television producer that relies on capturing the attention of a constantly changing class of viewers. As networks began to understand the power of adolescent stories(and audiences), moreteen-centered shows started to appear and evolve.With the launches of Gossip Girl in 2007 and Pretty Little Liars in 2010, suddenly teen shows weren't just about love triangles. They needed more, like a mystery, like Riverdale and Elite putting high schoolers in the middle of unpredictable scenarios. “Along came the more hooky（逃学）kind of shows，”says Everwood creator Greg Berlanti. “Everything needed a high-concept package around it.” Often that concept would be supernatural-a trend that can be traced back through The Vampire Diaries and Buffy the Vampire Slayer, among others. Today that theme is bigger than ever thanks to fantasy epics like Netflix's Shadow and Bone.What does the future hold for teen TV? Whatever comes next, “authenticity is always the key,” says Berlanti. “They have to be truthful." And wherever there is an authentic teen story,there＇s one thing that we can guarantee will come with it：hormones（荷尔蒙）.Lots of hormones. ( D )1.According to the first paragraph, which of the following statements is TRUE?A. Teen TV used to be common and popular.B. Fox had much experience in making teen TV.C. Julie Plec was a big fan of The Vampire Diaries.D. Newness makes teen TV important.( C )2. What is the big challenge that teen TV producers face?A. To focus only on a fixed group of teens.B.To change the target viewers constantly.C. To create more new ideas and things.D.To maintain the old tradition.( D )3.How does the author develop the third paragraph?A. By making comments.B. By following time order.C.By explaining the process.。

Changes in the minimum alveolar concentration of isoflurane and some cardiopulmonary measurements du

R E S E A R C H P A P E RChanges in the minimum alveolar concentration ofisoﬂurane and some cardiopulmonary measurements during three continuous infusion rates of dexmedetomidine in dogsPeter J Pascoe*BVSc,Diplomate ACVA,Diplomate ECVA,Marja Raekallio DVM,PhD,Erja Kuusela DVM,PhD,Brett McKusickàDVM,MS,PhD&Mikael GranholmàDVM*Department of Surgical and Radiological Sciences,School of Veterinary Medicine,University of California,Davis,CA,USA Department of Clinical Sciences,Faculty of Veterinary Medicine,University of Helsinki,Helsinki,FinlandàOrion Pharma Animal Health,Turku,FinlandCorrespondence:Dr Peter J.Pascoe,Department of Surgical and Radiological Sciences,School of Veterinary Medicine,University of California,Davis,CA95616,USA.E-mail:pjpascoe@AbstractObjective To measure the change in the minimum alveolar concentration of isoﬂurane associated with three constant rate infusions of dexmedetomidine.Study Design Prospective,randomized,and blinded experimental trial.Animals Six healthy6-year-old Beagles weighing between13.0and17.7kg.Methods The dogs received each of four treatments; saline or dexmedetomidine at0.1,0.5or3l g kg)1 loading dose given intravenously(IV)over6min-utes followed by infusions at0.1,0.5or 3l g kg)1hour)1,respectively.There were2weeks between treatments.The dogs were mask-induced with and maintained on isoﬂurane in oxygen. Acetated Ringer’s(5mL kg)1hour)1)and saline or dexmedetomidine(each at0.5mL kg)1hour)1) were given IV.Pulse rate,blood pressure,samples for the measurement of blood gases,pH,lactate, packed cell volume(PCV),total protein(TP)and dexmedetomidine concentrations were obtained from an arterial catheter.Sixty minutes after induction minimum alveolar concentration(MAC) was determined by intermittently applying supra-maximal electrical stimuli to the thoracic and pelvic limbs.Cardiopulmonary measurements and arterial blood samples were collected before each set of stimuli.Statistical analyses were conducted with analysis of variance or mixed models according to the experimental design.Results There was a signiﬁcant decrease in the MAC of isoﬂurane associated with0.5and 3l g kg)1hour)1but not with0.1mg kg)1 hour)1.Serum concentrations of dexmedetomidine were not measurable at the0.1mg kg)1hour)1 and averaged0.198±0.081and 1.903±0.621ng mL)1for the0.5and3l g kg)1hour)1 infusion rates,respectively.Heart rate decreased with increasing doses of dexmedetomidine while blood pressure increased.Packed cell volume increased at 3l g kg)1hour)1but not with other doses.Conclusions and Clinical relevance Dexmedetomi-dine infusions decrease the intra-operative require-ment for isoﬂurane and may be useful in managing dogs undergoing surgery,where the provision of analgesia and limitation of the stress response is desirable.Keywords dexmedetomidine,heart rate,isoﬂurane, minimum alveolar concentration.97Veterinary Anaesthesia and Analgesia,2006,33,97–103doi:10.1111/j.1467-2995.2005.00236.xIntroductionThe main uses of a2-adrenoceptor agonists in veterinary medicine are to provide chemical re-straint,anxiolysis and analgesia.They may be used seperately or in combination with other sedative/ analgesics to allow veterinarians to carry out minor procedures such as suturing lacerations or radio-graphy.Alternatively,they may be used for preme-dication before anesthesia with other drugs,where they facilitate compliance of the animal for presur-gical preparation(e.g.clipping hair,placing an intravenous catheter)and reduce the doses of anes-thetic drugs needed for induction and maintenance (Vickery et al.1988;Hellebrekers&Sap1997).The doses of a2-agonists used for these purposes generally have signiﬁcant effects on cardiovascular function, especially in dogs(Pypendop&Verstegen1998; Sinclair et al.2003).Thus it is generally advised that a2-agonists should not be used in animals with compromised cardiovascular function.The increase in systemic vascular resistance associated with the potent a2-agonists may be of particular concern in patients with mitral regurgitation or dilated cardio-myopathy(Pypendop&Verstegen1998;Sinclair et al.2003).Given these effects it is interesting to note that a2-agonists are being used in human patients with coronary artery disease and that they are beneﬁting from such an approach(Mangano 1997;Wijeysundera et al.2003);these drugs are associated with decreased likelihood of tachycardia, reduced response to stress(Flacke et al.1987; Mangano1997;Talke et al.2000)and reduced mortality(Wijeysundera et al.2003).The doses of a2-agonists used in animals are larger than those used conventionally in human beings.With mede-tomidine,this difference may be partially attributed to the use of the less potent racemic mixture in animals, whereas the more potent dexmedetomidine isomer is usually used in human beings.If all the pharmaco-logical activity resides in the dex isomer then this could account for the dose of racemic medetomidine being,at most,twice that of dexmedetomidine. However,in the dog it is common to use doses of medetomidine exceeding10l g kg)1whereas the doses of dexmedetomidine used in human patients are often<1l g kg)1,i.e.more than a10-fold dif-ference in dose.This difference is greater than can be explained on the basis of allometric scaling.In dogs, medetomidine administered pre-operatively has been shown to reduce minimum alveolar concentration for inhalation(MAC)and peri-operative stress (Vickery et al.1988;Weitz et al.1991;Vaisanen et al.2002)but low doses of dexmedetomidine have not been used intraoperatively. Dexmedetomidine decreases the MAC of isoﬂurane in human patients when used as a continuous infusion(Aho et al.1991).The objective of this study was to determine the change in the MAC of isoﬂurane in dogs with three doses of dexmedetom-idine given as constant rate infusions following a loading dose for each infusion rate.Materials and methodsAnimals and study designThe project was approved by the Ethics Committee for Animal Experiments of the University of Helsinki. Six Beagles weighing between13.0and17.7kg, and aged6years were used in the project.They were found to be healthy on physical examination and were housed in a group in a large room and received outdoor exercise mercial dog food was given twice daily,and water was freely available.The dogs were anesthetized four times with isoﬂurane for determining minimum alveolar con-centration that prevented movement in response to a supramaximal stimulus in50%of the animals (MAC)(Eger et al.1965).On each occasion they received one of the four treatments that were assigned in random order.The four treatments were:saline,low dose dexmedetomidine(loading dose0.1l g kg)1IV followed by an infusion of 0.1l g kg)1hour)1),middle dose dexmedetomidine (loading dose0.5l g kg)1IV followed by an infu-sion of0.5l g kg)1hour)1),and high dose dex-medetomidine(loading dose3l g kg)1IV followed by an infusion of3l g kg)1hour)1).The dexmede-tomidine was made up in a saline solution such that the same infusion volumes were used for all four treatments.The loading doses were calculated on the basis of the pharmacokinetics of dexmedetom-idine(Kuusela et al.2000)and the method des-cribed by Wagner(1974).At least2weeks were allowed between treatments.AnesthesiaAfter placing a20SWG catheter(Optiva*2;Johnson &Johnson Medical,Brussels,Belgium)in a cephalic vein,anesthesia was induced using a mask and isoﬂurane delivered along with oxygen.AcetatedChanges in MAC of isoﬂurane with dexmedetomidine PJ Pascoe et al.98Ó2006Association of Veterinary Anaesthetists,33,97–103Ringer’s solution was infused at5mL kg)1hour)1 throughout the experiment.An arterial catheter (Arterial Cannula with FloSwitch;Becton Dickin-son,Swindon,UK)was placed in the dorsal pedal artery and connected to a disposable pressure transducer(Ohmeda DTX,Singapore)for measuring blood pressures(Life Scope6;Nihon Kohden,Tokyo, Japan)and collecting blood samples for blood gas and dexmedetomidine serum concentration analy-sis.Once samples of blood had been collected for serum analysis the loading dose of dexmedetomidine or saline(5mL kg)1hour)1)was begun and administered over6minutes.At the end of this period the infusion was decreased to the mainten-ance rate of0.5mL kg)1hour)1.The infusion was continued for at least60minutes before theﬁrst stimulus was applied.MonitoringEnd-tidal(E¢T)isoﬂurane,O2and CO2were monit-ored(Capnomac Ultima;Datex Engstro¨m,Helsinki, Finland).Heart rate,systolic,diastolic and mean arterial pressures were recorded prior to each sti-mulation.Arterial blood samples were collected for determining packed cell volume,total protein,PaO2, PaCO2,pH and lactate,bicarbonate and base excess concentrations(ABL555,Radiometer,Copenha-gen,Denmark)immediately before each stimula-tion.Body temperature was measured and the blood gas values were corrected to that body temperature. Body temperature was maintained between37.8 and39.6°C using a heated pad underneath the animal and a blanket over the animal,as needed.Measuring MACMinimum alveolar concentration(MAC)for isoﬂu-rane was determined in triplicate using a supra-maximal stimulus.The dog was stimulated with a subcutaneous electrical current,20mA at 50cycles second)1with1millisecond pulse dur-ation for60seconds(Viking IV with Viking Quest Master software;Nicolet Biomedical Inc,Madison, WI,USA).Electrodes were placed on the pelvic limb (laterally over the gastrocnemius)and the thoracic limb(laterally over the antebrachium)and these sites were stimulated separately by random allocation. Five minutes were allowed between stimulations. Gross purposeful movement was taken as a positive response to stimulation.An increase in respiratory rate,swallowing or muscle twitching were not taken as purposeful movement.If no response to stimulation occurred,end-tidal iso-ﬂurane concentration(F E¢ISO)was decreased by 10%,and if there was a positive response,F E¢ISO was increased by10%.End-tidal isoﬂurane concen-tration was held constant for at least20minutes before each stimulation.The person assessing the response to stimulation was blinded to the concen-tration of anesthetic and the infusion being used.If a positive response was obtained on the thoracic limb and a negative response on the pelvic limb(or vice versa)the direction of change of the anesthetic was decided by a coin toss and that direction was held until the stimulus response on that limb changed.Serum dexmedetomidine concentrationBlood was collected into serum tubes before each stimulation but concentrations of dexmedetomidine were not measured for all of them(see below).Serum was separated within3hours by centrifugation and frozen at)20°C until analysis.Samples were ana-lyzed before the infusion(control value),at theﬁrst and last testing times and at two other points during the infusion at roughly equally spaced intervals. Dexmedetomidine concentration was measured by a speciﬁc and sensitive gas chromatographic mass spectrometric method modiﬁed from the technique of Vuorilehto et al.(1989).The lower limit of detection for this method was0.05ng mL)1and the coefﬁcient of variation for the analysis was6.4%.Statistical analysisStatistical analyses were conducted using SAS for Windows which applied analysis of variance or mixed models according to the experimental design. The model included the following terms as appro-priate:dog(1–6),treatment(saline,0.1,0.5,or 3l g kg)1hour)1infusion),treatment sequence (1–4),time(before stimulation,atﬁrst stimulation, duringﬁrst third of experiment,during middle third of experiment,atﬁnal stimulation),and the treat-ment-by-time interaction.The cardiopulmonary variables measured around each MAC point for the thoracic limbs were used for comparisons between treatments.Model-based least squares means and estimates of treatment difference with correspond-ing95%conﬁdence intervals were calculated. Treatment differences were considered to be signi-ﬁcant at the level of p<0.05.Changes in MAC of isoﬂurane with dexmedetomidine PJ Pascoe et al.Ó2006Association of Veterinary Anaesthetists,33,97–10399Results The dogs were anesthetized for 5.83±1.61hours and there were no statistically signiﬁcant differences between the times taken for each of the treatments.As there were no signiﬁcant differences between the MAC values determined from the thoracic and pelvic limbs,the values reported are those from the thoracic limbs (Table 1).There was no difference between the MAC values determined during0.1l g kg )1hour )1and those determined duringsaline.At the 0.5and 3l g kg )1hour )1doses therewere signiﬁcant decreases in MAC compared withbaseline.Dexmedetomidine concentrations were below thelimit of detection during the lowest infusion rate.The concentrations at different times during the twohigher infusion rates are presented in Fig.1.Theconcentration of dexmedetomidine measured at theﬁrst stimulus was numerically lower than forsubsequent values but this was only signiﬁcant forthe 3l g kg )1hour )1infusion.There were no signiﬁcant differences in bodytemperature,respiratory rate PaCO 2,PaO 2,pH,HCO 3,base excess,TP and lactate between treat-ments (Table 2).Packed cell volume increased forthe 3l g kg )1hour )1compared with the salinetreatment.Heart rate decreased with increasingdoses of dexmedetomidine and this was signiﬁcantlylower than baseline for the two higher doses ofdexmedetomidine.Systolic and mean arterial pres-sures were increased above baseline with the3l g kg )1hour )1dose and diastolic pressure in-creased for both higher doses of dexmedetomidine.DiscussionAlpha-2agonists have been shown to decrease theMAC of inhalant anesthetics in dogs in a number ofstudies (Bloor &Flacke 1982;Tranquilli et al.1984;Weitz et al.1991;Bloor et al.1992;Ewing et al.1993;Salmenpera et al.1994).Dexmedetomidine reduced the MAC of halothane in dogs by 30,60and >90%using 1,3,and 10l g kg )1IV,(Vickery et al.1988),respectively.The reduction at 3l g kg )1is similar to that found in this study with a continuous infusion of 3l g kg )1hour )1.In two other studies on dogs dexmedetomidine at an IV dose of 20l g kg )1reduced the MAC of isoﬂurane by 86%(Weitz et al.1991)and 89%(Bloor et al.1992).In human patients,infusions of dexmedetomidine,achieving plasma concentrations of 0.37±0.09and 0.6±0.16ng mL )1(mean ±SD),decreased the MAC of isoﬂurane by 37and 44%respectively (Aantaa et al.1997).Both plasma concentrations and MAC values lie between the values determined in this study but,as those patients also received alfent-anil and thiopental,it is hard to make direct com-parisons.In another study of older human patients (55–70years)with similar target plasma concen-trations (measured values 0.39±0.13and 0.7±0.13ng mL )1)the MAC of sevoﬂurane was notTable 1Mean (±SD)minimum alveo-lar concentration (MAC)in six dogsadministered a continuous infusionof dexmedetomidine at three differentdose rates SalineDexmedetomidine infusion 0.1(l g kg )1hour )1)0.5(l g kg )1hour )1)3(l g kg )1hour )1)MAC 1.51±0.25 1.41±0.251.22±0.27*0.62±0.16*MAC,%change relative to saline 0)6±8)18±12*)59±7**Treatment mean values within a given variable differ from saline control values(p <0.05).Changes in MAC of isoﬂurane with dexmedetomidine PJ Pascoe et al.100Ó2006Association of Veterinary Anaesthetists,33,97–103signiﬁcantly decreased with the low dose but there was a17%decrease with the higher dose(Fragen& Fitzgerald1999).The latter results are different from the values in our study and those of Aantaa et al.(1997)and that discrepancy could be related to the use of a different inhaled agent or to the age of the patients.The values for isoﬂurane MAC without dexmede-tomidine recorded in the current study are higher than those measured by others for this species(Steffey &Howland1977;Valverde et al.2003).The dogs used in this study had been used in previous studies involving various anesthetics but had not been used for several months since any previous work.The electrical stimulus was slightly different from that reported by others,in that the duty cycle was 1millisecond and not10milliseconds.However,in preliminary work using one animal,there appeared to be equivalence between the electrical stimulus and a mechanical stimulus(tail clamp).Based on clinical signs(palpebral response,jaw tone,and vigor of spontaneous movement in response to noxious stimulation)the dogs were not deeply anesthetized at the measured concentrations.The design of the study was set up to see if there was a difference between the MAC value recorded on the thoracic and pelvic limbs.With isoﬂurane and halothane alone this has been shown to be equal for thoracic and pelvic limbs(Valverde et al.2003). Anecdotally it has been suggested that a2-agonists provide better analgesia over the cranial part of the body.This effect has been demonstrated in horses where analgesia on the thoracic limbs was more intense and lasted longer than analgesia in the pelvic limbs or perineum(Hamm et al.1995)but it has not been demonstrated scientiﬁcally in dogs.We were unable to detect a difference between the thoracic limbs and pelvic limbs using this electrical stimulus, suggesting that for the purposes of surgery(also a supramaximal stimulus)an infusion of dexmedetom-idine would not provide any advantage for cranial versus caudal sites.The cardiopulmonary effects of these continuous infusions are similar to those noted with a2-agonists in other studies(Vickery et al.1988;Bloor et al.1992;Pypendop&Verstegen1998).Systemic blood pressure increased with increasing doses of dexmedetomidine,presumably as a result of a2-mediated vasoconstriction;it is notable that the diastolic pressure increased with the middle dose (0.5l g kg)1)although the changes in systolic and mean pressure were not signiﬁcant.It is unlikely that the increased blood pressure with the higher doses was because of the lower doses of isoﬂurane asTable2Mean values(±SD)for cardiovascular,respiratory,hematology,and body temperature variables measured during the entire experimental duration for six dogs administered a continuous infusion of dexmedetomidine at three different dose ratesVariable SalineDexmedetomidine infusion0.1(l g kg)1hour)1)0.5(l g kg)1hour)1)3(l g kg)1hour)1)Experimental duration(hours) 5.4±1.1 6.0±1.8 5.2±1.5 6.8±1.8 Respiratory rate(beats minute)1)60±6750±3453±6119±32Heart rate(beats minute)1)138±28121±2193±27*52±9* Systolic arterial pressure(mmHg)113±14117±16128±13160±20* Diastolic arterial pressure(mmHg)53±858±1067±11*93±12*Mean arterial pressure(mmHg)73±1075±1184±11109±15* Arterial pH7.353±0.057.355±0.057.396±0.047.395±0.04 PaCO2(mmHg)46.6±8.147.0±6.742.4±6.341.7±5.2PaO2(mmHg)557.1±43.3557.4±22.8563.2±24.2561.9±18.2 Lactate(mmol L)1) 1.8±0.6 1.4±0.6 1.6±0.7 1.4±0.5Base excess(mmol L)1))0.4±0.60.0±0.90.8±1.60.5±1.4HCO3(mmol L)1)24.6±1.524.8±1.224.8±2.124.3±1.8 Packed cell volume(%)37.4±2.435.9±2.237.6±3.144.4±2.1*Total protein concentration(g L)1)47.9±4.148.1±3.548.8±3.349.2±4.7Body temperature(°C)38.4±0.338.7±0.338.3±0.538.7±0.4*Treatment mean values within a given variable differ from saline control values(p<0.05).The values used were recorded around the MAC points for the foreleg.Changes in MAC of isoﬂurane with dexmedetomidine PJ Pascoe et al.Ó2006Association of Veterinary Anaesthetists,33,97–103101it is known that cardiac ouput is likely to be lower under these conditions.Without measuring cardiac output it is not possible to determine the degree of change that occurred but other studies have found signiﬁcant increases in systemic vascular resistance and decreases in cardiac output with an IV mede-tomidine dose of1l g kg)1(Pypendop&Verstegen 1998)and an IV dexmedetomidine dose of0.75–1.25l g kg)1(Flacke et al.1993;Lawrence et al. 1996;Pagel et al.1998).Bradycardia was evident at the highest dose in this study with one dog having heart rates below40beats minute)1for most of the study.The infusion rates of dexmedetomidine chosen for this study were based on data from human beings,as noted above,and chosen with a view to identifying the minimum infusion rate that would produce a clinically signiﬁcant decrease in MAC. The loading doses were based on the pharmaco-kinetics of dexmedetomidine,as determined in a previous study in dogs(Kuusela et al.2000).That pharmacokinetic study was carried out in con-cious animals and in the current study dexmede-tomidine was administered after the induction of anesthesia with isoﬂurane.As the initial dexmede-tomidine concentrations reported in this study were slightly lower than the later values,the loading dose may have been insufﬁcient but a relatively steady-state was reached by the time of the second sample after2–3hours of infusion; given a terminal half-life of0.78hours(Kuusela et al.2000)this would be at3–4half-lives;the normal expectation is that steady-state would be reached at5half-lives.In conclusion,this study shows that dexmede-tomidine at a constant rate infusion of0.5or 3l g kg)1hour)1reduces the MAC of isoﬂurane. These infusion rates have minimal effect on venti-lation but have signiﬁcant effects on some cardio-vascular variables.AcknowledgementsThe authors would like to thank Orion Pharma for funding this project,analyzing the serum concen-trations of dexmedetomidine and carrying out the statistical analysis.ReferencesAantaa R,Jaakola ML,Kallio A et al.(1997)Reduction of the minimum alveolar concentration of isoﬂurane bydexmedetomidine.Anesthesiology86,1055–1060.Aho M,Lehtinen AM,Erkola O et al.(1991)The effect of intravenously administered dexmedetomidine on peri-operative hemodynamics and isoﬂurane requirements in patients undergoing abdominal hysterectomy.Anes-thesiology74,997–1002.Bloor BC,Flacke WE(1982)Reduction in halothane an-esthetic requirement by clonidine,an alpha-adrenergic agonist.Anesth Analg61,741–745.Bloor BC,Frankland M,Alper G et al.(1992)Hemo-dynamic and sedative effects of dexmedetomidine in dog. J Pharmacol Exp Ther263,690–697.Eger EI II,Saidman LJ,Brandstater B(1965)Minimum alveolar anesthetic concentration:a standard of anes-thetic potency.Anesthesiology26,756–763.Ewing KK,Mohammed HO,Scarlett JM et al.(1993) Reduction of isoﬂurane anesthetic requirement by medetomidine and its restoration by atipamezole in dogs.Am J Vet Res54,294–299.Flacke JW,Bloor BC,Flacke WE et al.(1987)Reduced narcotic requirement by clonidine with improved hemo-dynamic and adrenergic stability in patients under-going coronary bypass surgery.Anesthesiology67, 11–19.Flacke WE,Flacke JW,Bloor BC et al.(1993)Effects of dexmedetomidine on systemic and coronary hemo-dynamics in the anesthetized dog.J Cardiothorac Vasc Anesth7,41–49.Fragen RJ,Fitzgerald PC(1999)Effect of dexmedetomidine on the minimum alveolar concentration(MAC)of sevoﬂurane in adults age55to70years.J Clin Anesth 11,466–470.Hamm D,Turchi P,Jochle W(1995)Sedative and anal-gesic effects of detomidine and romiﬁdine in horses.Vet Rec136,324–327.Hellebrekers LJ,Sap R(1997)Medetomidine as a preme-dicant for ketamine,propofol or fentanyl anaesthesia in dogs.Vet Rec140,545–548.Kuusela E,Raekallio M,Anttila M et al.(2000)Clinical effects and pharmacokinetics of medetomidine and its enantiomers in dogs.J Vet Pharmacol Ther23, 15–20.Lawrence CJ,Prinzen FW,de Lange S(1996)The effect of dexmedetomidine on nutrient organ bloodﬂow.Anesth Analg83,1160–1165.Mangano D(1997)Perioperative sympatholysis.Beneﬁcial effects of the alpha2-adrenoceptor agonist mivazerol on hemodynamic stability and myocardial ischemia. McSPI–Europe Research Group.Anesthesiology86, 346–363.Pagel PS,Hettrick DA,Kersten JR et al.(1998)Dex-medetomidine produces similar alterations in the deter-minants of left ventricular afterload in conscious dogs before and after the development of pacing-induced cardiomyopathy.Anesthesiology89,741–748.Changes in MAC of isoﬂurane with dexmedetomidine PJ Pascoe et al.102Ó2006Association of Veterinary Anaesthetists,33,97–103Pypendop B,Verstegen J(1998)Hemodynamic effects of medetomidine in the dog:a dose titration study.Vet Surg27,612–622.Salmenpera MT,Szlam F,Hug CCJ(1994)Anesthetic and hemodynamic interactions of dexmedetomidine and fentanyl in dogs.Anesthesiology80,837–846. Sinclair MD,O’Grady M,Kerr C et al.(2003)The echo-cardiographic effects of romiﬁdine in dogs with and without prior or concurrent administration of glyco-pyrrolate.Vet Anaesth Analg30,239–247.Steffey EP,Howland D Jr(1977)Isoﬂurane potency in the dog and cat.Am J Vet Res38,1833–1836.Talke P,Chen R,Thomas B et al.(2000)The hemo-dynamic and adrenergic effects of perioperative dex-medetomidine infusion after vascular surgery.Anesth Analg90,834–839.Tranquilli WJ,Thurmon JC,Corbin JE et al.(1984) Halothane-sparing effect of xylazine in dogs and sub-sequent reversal with tolazoline.J Vet Pharmacol Ther 7,23–28.Vaisanen M,Raekallio M,Kuusela E et al.(2002)Evalu-ation of the perioperative stress response in dogs administered medetomidine or acepromazine as part of the preanesthetic medication.Am J Vet Res63,969–975.Valverde A,Morey TE,Hernandez J et al.(2003)Valid-ation of several types of noxious stimuli for use indetermining the minimum alveolar concentration for inhalation anesthetics in dogs and rabbits.Am J Vet Res 64,957–962.Vickery RG,Sheridan BC,Segal IS et al.(1988)Anesthetic and hemodynamic effects of the stereoisomers of mede-tomidine,an alpha2-adrenergic agonist,in halothane-anesthetized dogs.Anesth Analg67,611–615. Vuorilehto L,Salonen JS,Anttila M(1989)Picogram level determination of medetomidine in dog serum by capil-lary gas chromatography with negative ion chemical ionization mass spectrometry.J Chromatogr497,282–287.Wagner JG(1974)A safe method for rapidly achieving plasma concentration plateaus.Clin Pharmacol Ther 16,691–700.Weitz JD,Foster SD,Waugaman WR et al.(1991)Anes-thetic and hemodynamic effects of dexmedetomidine during isoﬂurane anesthesia in a canine model.Nurse Anesth2,19–27.Wijeysundera DN,Naik JS,Beattie WS(2003)Alpha-2 adrenergic agonists to prevent perioperative cardiovas-cular complications:a meta-analysis.Am J Med114, 742–752.Received12January2004;accepted29October2004.Changes in MAC of isoﬂurane with dexmedetomidine PJ Pascoe et al.Ó2006Association of Veterinary Anaesthetists,33,97–103103。

ACCA F4-F9模拟题及解析(4)

ACCA F4-F9模拟题及解析（4）1、 The following trial balance relates to Quincy as at 30 September 2012:$’000 $’000Revenue (note (i)) 213,500Cost of sales 136,800Distribution costs 12,500Administrative expenses (note (ii)) 19,000Loan note interest and dividend paid (notes (ii) and (iii)) 20,700Investment income 400Equity shares of 25 cents each 60,0006% loan note (note (ii)) 25,000Retained earnings at 1 October 2011 18,500Land and buildings at cost (land element $10 million) (note (iv)) 50,000Plant and equipment at cost (note (iv)) 83,700Accumulated depreciation at 1 October 2011: buildings 8,000plant and equipment 33,700Equity financial asset investments (note (v)) 17,000Inventory at 30 September 2012 24,800Trade receivables 28,500Bank 2,900Current tax (note (vi)) 1,100Deferred tax (note (vi)) 1,200Trade payables 36,700–––––––– ––––––––397,000 397,000–––––––– –––––––– The following notes are relevant:(i) On 1 October 2011, Quincy sold one of its products for $10 million (included in revenue in the trial balance).As part of the sale agreement, Quincy is committed to the ongoing servicing of this product until 30 September2014 (i.e. three years from the date of sale). The value of this service has been included in the selling price of $10 million. The estimated cost to Quincy of the servicing is $600,000 perannum and Quincy’s normal gross profit margin on this type of servicing is 25%. Ignore discounting. (ii) Quincy issued a $25 million 6% loan note on 1 October 2011. Issue costs were $1 million and these have been charged to administrative expenses. The loan will be redeemed on 30 September 2014 at a premium which gives an effective interest rate on the loan of 8%.(iii) Quincy paid an equity dividend of 8 cents per share during the year ended 30 September 2012. (iv) Non-current assets:Quincy had been carrying land and buildings at depreciated cost, but due to a recent rise in property prices, it decided to revalue its property on 1 October 2011 to market value. An independent valuer confirmed the value of the property at $60 million (land element $12 million) as at that date and the directors accepted this valuation.The property had a remaining life of 16 years at the date of its revaluation. Quincy will make a transfer from the revaluation reserve to retained earnings in respect of the realisation of the revaluation reserve. Ignore deferred tax on the revaluation.Plant and equipment is depreciated at 15% per annum using the reducing balance method.No depreciation has yet been charged on any non-current asset for the year ended 30 September 2012. All depreciation is charged to cost of sales.(v) The investments had a fair value of $15·7 million as at 30 September 2012. There were no acquisitions or disposals of these investments during the year ended 30 September 2012.(vi) The balance on current tax represents the under/over provision of the tax liability for the year ended 30 September 2011. A provision for income tax for the year ended 30 September 2012 of $7·4 million is required. At 30 September 2012, Quincy had taxable temporary differences of $5 million, requiring a provision for deferred tax. Any deferred tax adjustment should be reported in the income statement. The income tax rate of Quincy is 20%.Required:(a) Prepare the statement of comprehensive income for Quincy for the year ended 30 September 2012.(b) Prepare the statement of changes in equity for Quincy for the year ended 30 September 2012.(c) Prepare the statement of financial position for Quincy as at 30 September 2012.Note: Notes to the financial statements are not required.The following mark allocation is provided as guidance for this question:(a) 11 marks(b) 4 marks(c) 10 marks(25 marks)2、Quartile sells jewellery through stores in retail shopping centres throughout the country.Over the last two years it has experienced declining profitability and is wondering if this is related to the sector as whole. It has recently subscribed to an agency that produces average ratios across many businesses. Below are the ratios that have been provided by the agency for Quartile’s business sector based on a year end of 30 June 2012.Return on year-end capital employed (ROCE) 16·8% Net asset (total assets less current liabilities) turnover 1·4 timesGross profit margin 35%Operating profit margin 12%Current ratio 1·25:1Average inventory turnover 3 timesTrade payables’ payment period 64 daysDebt to equity 38%The financial statements of Quartile for the year ended 30 September 2012 are:Income statement$’000 $’000Revenue 56,000Opening inventory 8,300Purchases 43,900–––––––52,200Closing inventory (10,200) (42,000)––––––– ––––––– Gross profit 14,000Operating costs (9,800)Finance costs (800)–––––––Profit before tax 3,400Income tax expense (1,000)–––––––Profit for the year 2,400––––––– Statement of financial position$’000 $’000AssetsNon-current assetsProperty and shop fittings 25,600Deferred development expenditure 5,000–––––––30,600Current assetsInventory 10,200Bank 1,000 11,200––––––– –––––––Total assets 41,800––––––– Equity and liabilitiesEquityEquity shares of $1 each 15,000Property revaluation reserve 3,000Retained earnings 8,600–––––––26,600Non-current liabilities10% loan notes 8,000Current liabilitiesTrade payables 5,400Current tax payable 1,800 7,200––––––– –––––––Total equity and liabilities 41,800––––––– Note: The deferred development expenditure relates to an investment in a process to manufacture artificial precious gems for future sale by Quartile in the retail jewellery market. Required:(a) Prepare for Quartile the equivalent ratios that have been provided by the agency. (9 marks)(b) Assess the financial and operating performance of Quartile in comparison to its sector averages.(12 marks)(c) Explain four possible limitations of the usefulness of the above comparison. (4 marks)(25 marks)3、(a) Two of the qualitative characteristics of information contained in the HKICPA’s Conceptual Framework for Financial Reporting are understandability and comparability.Required:Explain the meaning and purpose of the above characteristics in the context of financial reporting and discuss the role of consistency within the characteristic of comparability in relation to changes in accounting policy.(6 marks)(b) Lobden is a construction contract company involved in building commercial properties. Its current policy for determining the percentage of completion of its contracts is based on the proportion of cost incurred to date compared to the total expected cost of the contract.One of Lobden’s contracts has an agreed price of $250 million and estimated total costs of $200 million.The cumulative progress of this contract is:Year ended: 30 September 2011 30 September 2012$million $millionCosts incurred 80 145Work certified and billed 75 160Billings received 70 150Based on the above, Lobden prepared and published its financial statements for the year ended 30 September2011. Relevant extracts are:Income statement$millionRevenue (balance) 100Cost of sales (80)––––Profit (50 x 80/200) 20–––– Statement of financial position $millionCurrent assetsAmounts due from customersContract costs to date 80Profit recognised 20––––100Progress billings (75)––––25–––– Contract receivables (75 – 70) 5Lobden has received some adverse publicity in the financial press for taking its profit too early in the contract process, leading to disappointing profits in the later stages of contracts. Most of Lobden’s competitors take profit based on the percentage of completion as determined by the work certified compared to the contract price.Required:(i) Assuming Lobden changes its method of determining the percentage of completion of contracts to that used by its competitors, and that this would represent a change in an accounting estimate, calculate equivalent extracts to the above for the year ended 30 September 2012; (7 marks) (ii) Explain why the above represents a change in accounting estimate rather than a change in accounting policy. (2 marks) (15 marks)4、(a) Shawler is a small manufacturing company specialising in making alloy castings. Its main item of plant is a furnace which was purchased on 1 October 2009. The furnace has two components: the main body (cost $60,000 including the environmental provision – see below) which has a ten-year life, and a replaceable liner (cost $10,000) with a five-year life.The manufacturing process produces toxic chemicals which pollute the nearby environment. Legislation requires that a clean-up operation must be undertaken by Shawler on 30 September 2019 at the latest. Shawler received a government grant of $12,000 relating to the cost of the main body of the furnace only.The following are extracts from Shawler’s statement of financial position as at 30 September 2011 (two years after the acquisition of the furnace):Carrying amount$Non-current assetsFurnace: main body 48,000replaceable liner 6,000Current liabilitiesGovernment grant 1,200Non-current liabilitiesGovernment grant 8,400Environmental provision 18,000 (present value discounted at 8% per annum)Required:(i) Prepare equivalent extracts from Shawler’s statement of financial position as at 30 September 2012;(3 marks)(ii) Prepare extracts from Shawler’s income statement for the year ended 30 September 2012 relating to the items in the statement of financial position. (3 marks)(b) On 1 April 2012, the government introduced further environmental legislation which had the effect of requiring Shawler to fit anti-pollution filters to its furnace within two years. An environmental consultant has calculated that fitting the filters will reduce Shawler’s required environmental costs (and therefore its provision) by 33%. At 30 September 2012 Shawler had not yet fitted the filters.Required:Advise Shawler as to whether they need to provide for the cost of the filters as at 30 September 2012 and whether they should reduce the environmental provision at this date. (4 marks)(10 marks)试题答案：1、(a)Quincy – Statement of comprehensive income for the year ended 30 September 2012$’000Revenue (213,500 – 1,600 (w (i))) 211,900Cost of sales (w (ii)) (147,300)––––––––Gross profit 64,600Distribution costs (12,500) Administrative expenses (19,000 – 1,000 loan issue costs (w (iv))) (18,000)Loss on fair value of equity investments (17,000 – 15,700) (1,300)Investment income 400Finance costs (w (iv)) (1,920)–––––––– Profit before tax 31,280Income tax expense (7,400 + 1,100 – 200 (w (v))) (8,300)––––––––Profit for the year 22,980Other comprehensive incomeGain on revaluation of land and buildings (w (iii)) 18,000––––––––Total comprehensive income 40,980–––––––– (b)Quincy – Statement of changes in equity for the year ended 30 September 2012Share Revaluation Retained Total capital reserve earnings equity$’000 $’000 $’000 $’000Balance at 1 October 2011 60,000 nil 18,500 78,500Total comprehensive income 18,000 22,980 40,980Transfer to retained earnings (w (iii)) (1,000) 1,000 nilDividend paid (60,000 x 4 x 8 cents) (19,200) (19,200)––––––– ––––––– ––––––– ––––––––Balance at 30 September 2012 60,000 17,000 23,280 100,280––––––– ––––––– ––––––– –––––––– (c)Quincy – Statement of financial position as at 30 September 2012Assets $’000 $’000Non-current assetsProperty, plant and equipment (57,000 + 42,500 (w (iii))) 99,500Equity financial asset investments 15,700––––––––115,200Current assetsInventory 24,800Trade receivables 28,500Bank 2,900 56,200––––––– ––––––––Total assets 171,400–––––––– Equity and liabilitiesEquityEquity shares of 25 cents each 60,000Revaluation reserve 17,000Retained earnings 23,280 40,280––––––– ––––––––100,280Non-current liabilitiesDeferred tax (w (v)) 1,000Deferred revenue (w (i)) 8006% loan note (2014) (w (iv)) 24,420 26,220–––––––Current liabilitiesTrade payables 36,700Deferred revenue (w (i)) 800Current tax payable 7,400 44,900––––––– ––––––––Total equity and liabilities 171,400–––––––– Workings (figures in brackets in $’000)(i) Sales made which include revenue for ongoing servicing work must have part of the revenue deferred. The deferred revenue must include the normal profit margin (25%) for the deferred work. At 30 September 2012, there are two more years of servicing work, thus $1·6 million ((600 x 2) x 100/75) must be treated as deferred revenue, split equally between current and non-current liabilities.(ii) Cost of sales$’000Per trial balance 136,800Depreciation of building (w (iii)) 3,000Depreciation of plant (w (iii)) 7,500––––––––147,300–––––––– (iii) Non-current assetsLand and buildings:The gain on revaluation and carrying amount of the land and buildings is:Land Building$’000 $’000Carrying amount as at 1 October 2011 10,000 (40,000 – 8,000) 32,000Revalued amount as at this date (12,000) (60,000 – 12,000) (48,000)––––––– –––––––Gain on revaluation 2,000 16,000––––––– ––––––– Building depreciation year to 30 September 2012 (48,000/16 years) 3,000The transfer from the revaluation reserve to retained earnings in respect of ‘excess’ depreciation (as the revaluation is realised) is $1 million (48,000 – 32,000)/16 years.The carrying amount at 30 September 2012 is $57 million (60,000 – 3,000).Plant and equipment:$’000Carrying amount as at 1 October 2011 (83,700 – 33,700) 50,000Depreciation at 15% per annum (7,500)–––––––Carrying amount as at 30 September 2012 42,500––––––– (iv) Loan noteThe finance cost of the loan note is charged at the effective rate of 8% applied to the carrying amount of the loan. Theissue costs of the loan ($1 million) should be deducted from the proceeds of the loan ($25 million) and not treated asan administrative expense. This gives an initial carrying amount of $24 million and a finance cost of $1,920,000(24,000 x 8%). The interest actually paid is $1·5 million (25,000 x 6%) and the difference between these amounts,of $420,000 (1,920 – 1,500), is accrued and added to the carrying amount of the loan note. This gives $24·42 million(24,000 + 420) for inclusion as a non-current liability in the statement of financial position. Note: The loan interest paid of $1·5 million plus the dividend paid of $19·2 million (see (b)) equals the $20·7 millionshown in the trial balance for these items.(v) Deferred tax$’000Provision required as at 30 September 2012 (5,000 x 20%) 1,000Less provision b/f (1,200)––––––Credit to income statement 200–––––– 2、(a) Below are the specified ratios for Quartile and (for comparison) those of the business sector average:Quartile sector averageReturn on year-end capital employed ((3,400 + 800)/(26,600 + 8,000) x 100) 12·1% 16·8%Net asset turnover (56,000/34,600) 1·6 times 1·4 timesGross profit margin (14,000/56,000 x 100) 25% 35%Operating profit margin (4,200/56,000 x 100) 7·5% 12%Current ratio (11,200:7,200) 1·6:1 1·25:1Average inventory (8,300 + 10,200/2) = 9,250) turnover (42,000/9,250) 4·5 times 3 timesTrade payables’ payment period (5,400/43,900 x 365) 45 days 64 daysDebt to equity (8,000/26,600 x 100) 30% 38%(b)Assessment of comparative performance ProfitabilityThe primary measure of profitability is the return on capital employed (ROCE) and this shows that Quartile’s 12·1% is considerably underperforming the sector average of 16·8%. Measured as a percentage, this underperformance is 28% ((16·8–12·1)/16·8). The main cause of this seems to be a much lower gross profit margin (25% compared to 35%). A possible explanation for this is that Quartile is deliberately charging a lower mark-up in order to increase its sales by undercutting the market. There is supporting evidence for this in that Quartile’s average inventory turnover at 4·5 times is 50% better than the sector average of three times. An alternative explanation could be that Quartile has had to cut its margins due to poor sales which have had a knock-on effect of having to write down closing inventory.Quartile’s lower gross profit percentage has fed through to contribute to a lower operating profit margin at 7·5% compared to the sector average of 12%. However, from the above figures, it can be deduced that Quartile’s operating costs at 17·5% (25%– 7·5%) of revenue appear to be better controlled than the sector average operating costs of 23% (35% – 12%) of revenue.This may indicate that Quartile has a different classification of costs between cost of sales and operating costs than the companies in the sector average or that other companies may be spending more on advertising/selling commissions in order to support their higher margins.The other component of ROCE is asset utilisation (measured by net asset turnover). If Quartile’s business strategy is indeed to generate more sales to compensate for lower profit margins, a higher net asset turnover would be expected. At 1·6 times,Quartile’s net asset turnover is only marginally better than the sector average of 1·4 times.Whilst this may indicate that Quartile’s strategy was a poor choice, the ratio could be partly distorted by the property revaluation and also by whether the deferred development expenditure should be included within net assets for this purpose, as the net revenues expected from the development have yet to come on stream. If these two aspects were adjusted for, Quartile’s net asset turnover would be 2·1 times (56,000/(34,600 – 5,000 – 3,000)) which is 50% better than the sector average.In summary, Quartile’s overall profitability is below that of its rival companies due to considerably lower profit margins,although this has been partly offset by generating proportionately more sales from its assets.LiquidityAs measured by the current ratio, Quartile has a higher level of cover for its current liabilities than the sector average (1·6:1 compared to 1·25:1). Quartile’s figure is nearer the ‘norm’ of expected liquidity ratios, often quoted as between 1·5 and 2:1, ith the sector average (at 1·25:1) appearing worryingly low. The problem of this ‘norm’ is that it is generally accepted that it relates to manufacturing companies rather than retail companies, as applies to Quartile (and presumably also to the sector average). In particular, retail companies have very little, if any, trade receivables as is the case with Quartile. This makes a big difference to the current ratio and makes the calculation of a quick ratio largely irrelevant. Consequently, retail companies operate comfortably with much lower current ratios as their inventory is turned directly into cash. Thus, if anything, Quartile has a higher current ratio than might be expected. As Quartile has relatively low inventory levels (deduced from high inventory turnover figures), this means it must also have relatively low levels of trade payables (which can be confirmed from the calculated ratios). The low payables period of 45 days may be an indication of suppliers being cautious with the credit period they extend to Quartile, but there is no real evidence of this (e.g. the company is not struggling with an overdraft). In short,Quartile does not appear to have any liquidity issues.GearingQuartile’s debt to equity at 30% is lower than the sector average of 38%. Although the loan note interest rate of 10% might appear quite high, it is lower than the ROCE of 12·1% (which means shareholders are benefiting from the borrowings) and the interest cover of 5·25 times ((3,400 + 800)/800) is acceptable. Quartile also has sufficient tangible assets to give more than adequate security on the borrowings, therefore there appear to be no adverse issues in relation to gearing. ConclusionQuartile may be right to be concerned about its declining profitability. From the above analysis,it seems that Quartile may be addressing the wrong market (low margins with high volumes). The information provided about its rival companies would appear to suggest that the current market appears to favour a strategy of higher margins (probably associated with better quality and more expensive goods) as being more profitable. In other aspects of the appraisal, Quartile is doing well compared to other companies in its sector.(c)Factors which may limit the usefulness of the comparison with business sector averages:It is unlikely that all the companies that have been included in the sector averages will use the same accounting policies. In the example of Quartile, it is apparent that it has revalued its property; this will increase its capital employed and (probably) lower its ROCE (compared to if it did not revalue). Other companies in the sector may carry their property at historical cost.The accounting dates may not be the same for all the companies. In this example the sector averages are for the year ended 30 June 2012, whereas Quartile’s are for the year ended 30 September 2012. If the sector is exposed to seasonal trading (although this may be unlikely for jewellery), this could have a significant impact on many ratios, in particular working capital based ratios. To allow for this, perhaps Quartile could prepare a form of adjusted financial statements to 30 June 2012.It may be that the definitions of the ratios have not been consistent across all the companies included in the sector averages (and for Quartile). This may be a particular problem with ratios like ROCE as there is no universally accepted definition. Often agencies issue guidance on how the ratios should be calculated to minimise these possible inconsistencies. Of particular relevance in this example is that it is unlikely that other jewellery retailers will have an intangible asset of deferred development expenditure.16 Sector averages are just that: averages. Many of the companies included in the sector may not be a good match to the type of business and strategy of Quartile. ‘Jewellery’ is a broad category and some companies may adopt a strategy of high-end (expensive) goods which have high mark-ups, but usually lower inventory turnover, whereas other companies may adopt astrategy of selling more affordable jewellery with lower margins in the expectation of higher volumes.Note: Other relevant examples may be acceptable, but they must relate to issues of inter-company comparison and not general issues of interpretation such as inflation distorting profit trends.3、(a)The main objective of financial statements is to provide information that is useful toa wide range of users for the purpose of making economic decisions. Therefore, it is importantthat the activities and events of the entity, as expressed within the financial statements, are understood by users, meaning that their usefulness and relevance is maximised. This can present management with a problem because clearly not all users have the same (financial) abilities and knowledge. For the purpose of understandability, management are allowed to assume users do have a reasonable knowledge of accounting and business and are prepared to study the financial statements diligently. Importantly, this characteristic cannot be used by management to avoid disclosing complex information that may be relevant in user decision-making. However, management must recognise that too much or overly complex disclosure can obscure the more important aspects of an entity’s performance, i.e. important information should not be ‘buried’ in the detail of unfathomable information.Comparability is the main tool by which users can assess the performance of an entity. This can be done through trend analysis of the same entity’s financial statements over time (say five years), or by comparing one entity with other (suitable) entities (or business sector averages) for the same time period. This means that the measurement and disclosure (classification) of like transactions should be consistent over time for the same entity, and (ideally) between different entities.Consistency and comparability are facilitated by the existence and disclosure of accounting policies. The above illustrates the close correlation between comparability and consistency. However, it is not always possible for an entity to apply the same accounting policies every year; sometimes they have to change (e.g. because of a new accounting standard or a change inlegislation). Similarly, it is not practical for accounting standards to require all entities to adopt the same accounting policies.Thus, if an entity does change an accounting policy, this breaks the principle of consistency. In such circumstances, HKFRSs normally require that any reported comparatives (previous year’s financial statements) are restated as if the new policy had been in force when those statements were originally reported. In this way, although there has been a change of policy, comparability has been maintained.It is more difficult to address the issue of consistency across entities; as already stated, accounting standards cannot prescribe the use of the same policy for all entities (this would be uniformity). However, accounting standards do prohibit certain accounting treatments (considered inappropriate or inferior) and they do require entities to disclose their accounting policies,such that users become aware of differences between entities and this may allow them to make value adjustments when comparing entities using different policies.(b) (i) Lobden’s income statement (extracts) for the year ended:30 September 2012$millionRevenue (based on work certified) (160 – 100) 60Cost of sales (balance) (48)–––Profit ((50 x 160/250) – 20) 12––– Statement of financial position (extracts) as at:30 September 2012$millionCurrent assets:Amounts due from customersContract costs to date 145Profit recognised (cumulative 20 + 12) 32––––177Progress billings (cumulative) (160)––––Amounts due from customers 17––––Contract receivables (160 – 150) 10–––– (ii) The relevant issue here is what constitutes the accounting policy for construction contracts. Where there is uncertainty in the outcome of a contract, the appropriate accounting policy would be the completed contract basis (i.e. no profit is taken until the contract is completed). Similarly, any expected losses should be recognised immediately. Where the outcome of a contract is reasonably foreseeable, the appropriate accounting policy is to accrue profits by the percentage of completion method. If this is accepted, it becomes clear that the different methods of determining the percentage of completion of construction contracts are different accounting estimates. Thus the change made by Lobden in the year to 30 September 2012 represents a change of accounting estimate. This approach complies with the guidance in HKAS 11 Construction Contracts paras 30 and 38.4、 (a) (i)Shawler statement of financial position (extract) as at 30 September 2012Carrying amount。

tpo61三篇托福阅读TOEFL原文译文题目答案背景知识

tpo61三篇托福阅读TOEFL原文译文题目答案背景知识阅读-1 (2)原文 (2)译文 (5)题目 (7)答案 (13)背景知识 (15)阅读-2 (18)原文 (19)译文 (22)题目 (24)答案 (32)背景知识 (34)阅读-3 (39)原文 (39)译文 (42)题目 (45)答案 (53)背景知识 (54)阅读-1原文Physical Properties of Minerals①A mineral is a naturally occurring solid formed by inorganic processes. Since the internal structure and chemical composition of a mineral are difficult to determine without the aid of sophisticated tests and apparatus , the more easily recognized physical properties are used in identification.②Most people think of a crystal as a rare commodity, when in fact most inorganic solid objects are composed of crystals. The reason for this misconception is that most crystals do not exhibit their crystal form: the external form of a mineral that reflects the orderly internal arrangement of its atoms. Whenever a mineral forms without space restrictions, individual crystals with well-formed crystal faces will develop. Some crystals, such as those of the mineral quartz, have a very distinctive crystal form that can be helpful in identification. However, most of the time, crystal growth is interrupted because of competition for space, resulting in an intergrown mass of crystals, none of which exhibits crystal form.③Although color is an obvious feature of a mineral, it is often anunreliable diagnostic property. Slight impurities in the common mineral quartz, for example, give it a variety of colors, including pink, purple (amethyst), white, and even black. When a mineral, such as quartz, exhibits a variety of colors, it is said to possess exotic coloration. Exotic coloration is usually caused by the inclusion of impurities, such as foreign ions, in the crystalline structure. Other minerals —for example, sulfur, which is yellow, and malachite, which is bright green —are said to have inherent coloration because their color is a consequence of their chemical makeup and does not vary significantly.④Streak is the color of a mineral in its powdered form and is obtained by rubbing a mineral across a plate of unglazed porcelain. Whereas the color of a mineral often varies from sample to sample, the streak usually does not and is therefore the more reliable property.⑤Luster is the appearance or quality of light reflected from the surface of a mineral. Minerals that have the appearance of metals, regardless of color, are said to have a metallic luster. Minerals with a nonmetallic luster are described by various adjectives, including vitreous (glassy) pearly, silky, resinous, and earthy (dull).⑥One of the most useful diagnostic properties of a mineral is hardness, the resistance of a mineral to abrasion or scratching. This property is determined by rubbing a mineral of unknown hardness against one ofknown hardness, or vice versa. A numerical value can be obtained by using Mohs' scale of hardness, which consists of ten minerals arranged in order from talc, the softest, at number one, to diamond, the hardest, at number ten. Any mineral of unknown hardness can be compared with these or with other objects of known hardness. For example, a fingernail has a hardness of 2.5, a copper penny 5, and a piece of glass 5.5. The mineral gypsum, which has a hardness of two, can be easily scratched with your fingernail. On the other hand, the mineral calcite which has a hardness of three, will scratch your fingernail but will not scratch glass. Quartz, the hardest of the common minerals, will scratch a glass plate.⑦The tendency of a mineral to break along planes of weak bonding is called cleavage. Minerals that possess cleavage are identified by the smooth, flat surfaces produced when the mineral is broken. The simplest type of cleavage is exhibited by the micas. Because the micas have excellent cleavage in one direction, they break to form thin, flat sheets. Some minerals have several cleavage planes, which produce smooth surfaces when broken, while others exhibit poor cleavage, and still others exhibit no cleavage at all. When minerals break evenly in more than one direction, cleavage is described by the number of planes exhibited and the angles at which they meet. Cleavage should not be confused with crystal form. When a mineral exhibits cleavage, itwill break into pieces that have the same configuration as the original sample does. By contrast, quartz crystals do not have cleavage, and if broken, would shatter into shapes that do not resemble each other or the original crystals. Minerals that do not exhibit cleavage are said to fracture when broken. Some break into pieces with smooth curved surfaces resembling broken glass. Others break into splinters or fibers, but most fracture irregularly.译文矿物的物理性质①矿物质是由无机过程形成的天然固体。

四川省成都外国语学校2023-2024学年高一下学期7月月考英语试题

四川省成都外国语学校2023-2024学年高一下学期7月月考英语试题一、听力选择题1．What is the probable relationship between the speakers?A．Mum and son.B．Teacher and student.C．Doctor and patient. 2．When will the woman take her flight?A．On the 22nd.B．On the 23rd.C．On the 24th.3．What are the speakers mainly talking about?A．School activities.B．Favorite subjects.C．Test scores.4．What does the woman mean?A．The man has to leave.B．She offers another option.C．She can’t make it. 5．Where does the conversation take place?A．In a bookstore.B．At a restaurant C．In a library.听下面一段对话，回答以下小题。

6．Why does Monica choose Tai Chi instead of yoga?A．It enjoys popularity.B．It requires less tension.C．It reflects Chinese culture. 7．What’s the true significance of Tai Chi?A．Maintaining balance.B．Strengthening muscles.C．Preventing diseases.听下面一段对话，回答以下小题。

8．Why does George want to go to the book exhibition?A．To buy a book.B．To meet a penfriend.C．To do a book signing. 9．What will the woman do before going to the book exhibition?A．Visit her parents.B．Go to her son’s school.C．Pick up Sarah.听下面一段对话，回答以下小题。

托福听力tpo40 全套对话讲座原文+题目+答案+译文

托福听力tpo40 全套对话讲座原文+题目+答案+译文Section 1 (2)Conversation1 (2)原文 (2)题目 (5)答案 (7)译文 (7)Lecture1 (9)原文 (9)题目 (12)答案 (15)译文 (15)Lecture2 (17)原文 (17)题目 (21)答案 (23)译文 (23)Section 2 (26)Conversation2 (26)原文 (26)题目 (28)答案 (30)译文 (30)Lecture3 (32)原文 (32)题目 (36)答案 (39)译文 (39)Lecture4 (42)原文 (42)题目 (45)答案 (48)译文 (48)Section 1Conversation1原文NARRATOR: Listen to a conversation between a student and a business professor.MALE STUDENT: Thanks for seeing me, Professor Jackson.FEMALE PROFESSOR: Sure, Tom. What can I do for you?MALE STUDENT: I'm gonna do my term project on service design, uh, what you see as a customer …the physical layout of the building, the parking lot. And I thought I'd focus on various kinds of eateries …restaurants, coffee shops, cafeterias, so I'd also analyze where you order your food, where you eat, and so on.FEMALE PROFESSOR: Wait, I thought you were going to come up with a hypothetical business plan for an amusement park? Isn’t that what you e-mailed me last week?I could've sworn …. Oh! I'm thinking of a Tom from another class.Tom Benson. Sorry, sorry.MALE STUDENT: No problem. I did e-mail you my idea too, though …. FEMALE PROFESSOR: Oh, that's right. I remember now. Restaurants …yeah …MALE STUDENT: So, here's my question. I read something about service standard that kinda confused me. What’s the difference between service design and service standard?FEMALE PROFESSOR: Service standard refers to what a company …employees …are ideally supposed to do in order for everything to operate smoothly. The protocols to be followed.MALE STUDENT: Oh, OK.FEMALE PROFESSOR: Um, so backing up…Service design is…uh, think of the cafeteria here on campus. There are several food counters, right? All with big, clear signs to help you find what you're looking for—soups, salads, desserts—so you know exactly where to go to get what you need. And when you're finished picking up your food, where do you go?MALE STUDENT: To the cash registers.FEMALE PROFESSOR: And where are they?MALE STUDENT: Um, right before you get to the seating area.FEMALE PROFESSOR: Exactly. A place that you would logically move to next.MALE STUDENT: You know, not every place is like that. This past weekend was my friend's birthday, and I went to a bakery in town, to pick up a cake for her party. And the layout of the place was weird: People were allin each other's way, standing in the wrong lines to pay, to place orders…. Oh! And another thing? I heard this bakery makes really good apple pie, so I wanted to buy a slice of it, too.FEMALE PROFESSOR: OK.MALE STUDENT: There was a little label that said “apple pie,” where it's supposed to be, but there wasn’t any left.FEMALE PROFESSOR: And that's what's called a service gap. Maybe there wasn't enough training for the employees, or maybe they just ran out of pie that day. But something's wrong with the process, and the service standard wasn’t being met.MALE STUDENT: OK, I think I get it. Anyway, since part of the requirements for the term project is to visit an actual place of business, do you think I could use our cafeteria? They seem to have a lot of the things I'm looking for.FEMALE PROFESSOR: Well, campus businesses like the cafeteria or bookstore don't quite follow the kinds of service models we're studying in class. You should go to some other, local establishment, I'd say.MALE STUDENT: I see.FEMALE PROFESSOR: But just call the manager ahead of time so they aren't surprised.题目1.Why does the student go to see the professor?A. To find out all the requirements for a projectB. To discuss a service gap at a restaurantC. To get help understanding concepts relevant to his projectD. To get help with designing a business plan2.Why does the professor mention a student in another class?A. To describe an interesting topic for a projectB. To explain the cause of her initial confusionC. To point out that she has not received e-mails from all her students yetD. To indicate that she has several students doing projects about restaurants3.Why does the professor talk about the cafeteria on campus?A. To give an example of an effective service designB. To illustrate how service standards can inform service designC. To help the man understand a service problemD. To illustrate the concept of a service gap4.What do the speakers imply about the bakery the student went to recently? [Click on 2 answers.]A. The apple pie he bought there was not as good as it usually is.B. The bakery's service design was inefficient.C. The bakery needs additional employees to fix a service gap.D. The bakery did not meet a service standard.5.What does the professor say the student should do for his project?A. Compare an on-campus service model with an off-campus oneB. Interview the service manager and employees at the cafeteriaC. Recommend service improvements at the cafeteria and the bookstoreD. Analyze the service design of a nearby restaurant答案C B A BD D译文旁白：下面听一段学生和商务课教授间的对话。

2024上海静安区高三英语二模

静安区2023学年第二学期期中教学质量调研高三英语试卷(完卷时间：120分钟满分：140分)2024年4月考生注意：1. 试卷满分140分，完卷时间120分钟。

2. 本调研设试卷和答题纸两部分，全卷共12页。

所有答题必须涂(选择题)或写(非选择题)在答题纸上，做在试卷上一律不得分。

第I 卷(共100分)I. Listening ComprehensionSection ADirections: In Section A, you will hear ten short conversations between two speakers. At the end of each conversation,a question will be asked about what was said. The conversations and the questions will be spoken only once. After you hear a conversation and the question about it,read the four possible answers on your paper,and decide which one is the best answer to the question you have heard.1. A. At a grocery store. B. At a florist's stand.C. At a bank counter.D. At an electronic shop.2. A. Sign up for a fitness class. B. Shop for fitness equipment.C. Have a fitness test.D. Watch a fitness video.3. A. Pay the ticket right away. B. Challenge the ticket.C. Ignore the ticket.D. Apologize to the parking officer.4. A. She is available on Saturday. B. She will cancel her dentist appointment.C. She can not cover the man's shift.D. She forgot about the shift.5. A. The woman had better give him an extension on the deadline.B. The woman had better draft the proposal by herself.C. The woman had better approve the proposal.D. The woman had better give insights on the budget section.6. A. She doesn't like animals from the shelter.B. She prefers buying pets from breeders.C. She thinks adopting a pet is a bad idea.D. She supports the idea of adopting a pet.7. A. Either of them is an experienced chef.B. Both of them have experienced failures in the kitchen.C. Neither of them are fond of cooking.D. Both of them are concerned about the new recipe.8. A. Bungee jumping is safeB. Bungee jumping is thrilling.C. Bungee jumping might have risks.D. Bungee jumping is sure to be regrettable.9. A. The man should borrow the book several days later.B. The woman urgently needs the book back.C. The man does not need to return the book quickly.D. The woman is unwilling to lend the man the book.10. A. The woman's parents will not appreciate a surprise party.B. The woman should prioritize her parents' preferences for the party.C The man dislikes the idea of a surprise party.D. The woman should plan a party based on her own preferences.Section BDirections: In Section B,you will hear two short passages and one longer conversation. After each passage or conversation,you will be asked several questions. The passages and the conversation will be read twice,but the questions will be spoken only once. When you hear a question,read the four possible answers on your paper and decide which one would be the best answer to the question you have heard.Questions 11 through I3 are based on the following speech.11. A. A pupil in need of help. B. A person promising to donate money.C. A member from a charity.D. A teacher in the Semira Region.12. A. 10%. B. 35%. C. 50%. D. 65%.13. A. To train teachers for the disabled. B. To help a pupil with special needs.C. To pay for a walking holiday.D. To organize a charity club for the disabled.Questions 14 through 16 are based on the following passage.14. A. To distract other students from doing well.B. To impress his friends with the shining ring.C. To improve his chances in the exam.D. To honor his grandfather by wearing a ring.15. A. By having enough time for breaks.B. By breaking down learning into portions.C. By informing teachers of the study habits.D. By wearing lucky objects.16. A. Start revision ahead of time.B. Reward oneself during revision.C. Consider different learning styles.D. Stay up late for the exam.Questions 17 through 20 are based on the following conversation.17. A. To inquire about travel recommendations.B. To discuss cultural festivals in Southeast Asia.C. To plan a solo travel adventure to Thailand.D To learn about Mr. Patel's travel experiences.18. A. Europe and Africa. B. Thailand and VietnamC. South America and Australia.D. Japan and China.19. A. Solely cultural exploration.B. Primarily outdoor adventures.C. A mix of cultural and outdoor experiences.D. Luxurious and private accommodations.20. A. It is ideal for meeting fellow travelers.B. It offers exclusive travel experiences.C. It is a more comfortable and secure stay.D. It offers authentic cultural immersion.II. Grammar and VocabularySection ADirections:After reading the passage below,fill in the blanks to make the passages coherent and grammatically correct.For the blanks with a given word,fill in each blank with the proper form of the given word;for the other blanks,use one word that best fits each blank.Beethov-hen's first symphonyOn a grey Friday morning at a Hawke's Bay farm,members of New Zealand's symphony orchestra dressed in black to perform their latest composition in front of a large crowd.The music contained many marks of traditional classical music,but as it began,the instruments started to make loud,rough sounds more commonly __21__(hear)in chicken coops than in an auditorium.However,no feathers were angered by this departure from tradition, ___22__the audience that gathered to listen to the concert last week was,in fact,a couple of thousand chickens.The piece of music-Chook Symphony No. 1-__23__(create)specifically for the birds out of an unlikely partnership between the orchestra and an organic free-range chicken farm which wanted a piece of chicken-friendly music to enrich its flocks' lives.“We've been playing classical music for the chickens for some years now because ___24 ___ is well researched that the music can calm the chickens down,”says Ben Bostock,one of the two brothers who__25(own)the Bostock Brothers farm. Research has shown animals can respond positively to classical music,and chickens are particularly responsive to baroque(巴洛克格),according to some studies.The composer,Hamish Oliver,__26__used the baroque tradition as a starting point and drew inspiration from composers such as Corelli,Bach,and Schnitke,wanted the piece to be playful by including sounds from a chicken's world. “The trumpet imitates the c hicken …the woodwind instruments are the cluckiest,especially if you take the reeds off. ”The early stages of composition were spent _______(test)out which instruments and sounds the chickens responded to best.“They didn't like any big banging. ”Bostock said,adding that when the birds respond positively to themusic,they tend__28__(wander)farther among the trees. Bostock now hopes chicken farmers around the world will use the piece of music to calm their own birds.For Oliver,having input from the farmers about __ 29__the chickens were responding to particular sounds and instruments was a highlight of the project.The symphony has searched exhaustively __30__any other examples of orchestras making music specifically for chickens and believes this to be a world-first,says Peter Biggs,the orchestra's chief executive.Section BDirections :Complete the following passage by using the words in the box. Each word can only be used once. Note thatA new way to reduce poachingResearchers are working on a pilot program backed by Russia's Rosatom Corp to inject rhino horns(犀牛角)with radioactive material,a strategy that could discourage consumption and make it easier to detect illegal trade.Poachers(偷猎者)killed 394 rhinos in South Africa for their horns last year,government data shows,with public and private game __31__lacking the resources needed to monitor vast tracts of land and protect the animals that live there.While the toll was a third lower than in 2019 and the sixth __32_drop,illegal hunting remains the biggest threat to about 20,000 of the animals in the country —the world's biggest population.Thousands of__33__sensors along international borders could be used to detect a small quantity of radioactive material____34___into the horns,according to James Larkin,a professor at the University of Witswatersrand in Johannesburg,who has a background in radiation protection and nuclear security. “A whole new_35_of people could be able to detect the illegal movement of rhino horn,"he said. Some alternate methods of discouraging poaching,including poisoning, dyeing and removing the horns,have raised a variety of opinions as to their virtue and efficacy.Known as The Rhisotope Project,the new anti-poaching __36__started earlier this month with the injection of an amino acid(氨基酸)into two rhinos' horns in order to detect whether the compound will move into the animals' bodies. Also,__37__studies using computer modeling and a replica rhino head will be done to determine a safe dose of radioactive material. Rhino horn is used in traditional medicine,as it is believed to cure disease such as cancer,__38__as a show of wealth and given as gifts."If we make it radioactive, these people will be hesitant to buy it,"Larkin said. "We're pushing on the whole supply chain. "Besides Russia's state-owned nuclear company,the University of Witwatcrsrand. scientists and private rhino owners are involved in the project. If the method is ___39__feasible,it could also be used to curb illegal trade in elephant ivory.“Once we have developed the whole project and got to the poi nt where we completed the proof of concept,then we will be making this whole idea ____40_to whoever wants to use it. " Larkin said.III. Reading ComprehensionSection ADirections: For each blank in the following passages there are four words or phrases marked A, B. C and D. Fill in each blank with the word or phrase that best fits the context.City air is in a sorry state. It is dirty and hot. Outdoor pollution kills 4. 2m people a year, according to the World Health Organization. Concrete and tarmac meanwhile,absorb the sun's rays rather than reflecting them back into space,and also ___41 ___plants which would otherwise cool things down by evaporative transpiration(蒸腾作用). The never-ceasing__42_of buildings and roads thus tums urban areas into heat islands,discomforting residents and worsening dangerous heatwaves.A possible answer to the twin problems of pollution and heat is trees. Their leaves may destroy at least some chemical pollutants and they certainly __43__tiny particles floating in the air. which are then washed to the ground by rain. Besides transpiration,they provide __44___.To cool an area effectively, trees must be planted in quantity. Two years ago, researchers at the University of Wisconsin found that American cities need 40%tree___45___to cut urban heat back meaningfully. Unfortunately,not all cities —and especially not those now springing up in the world's poor and middle-income countries —are __46___with parks, private gardens or a sufficient number of street trees. And the problem is likely to get worse. At the moment,55%of people live in cities. By 2050 that share is expected to reach 68%.One group of botanists believe they have at least a partial ___47___to this lack of urban vegetation. It is to plant miniature simulacra(模拟物)of natural forests, ecologically engineered for rapid growth. Over the course of a career that began in the 1950s,their leader,Miyawaki Akira, a plant ecologist at Yokohama National University in Japan. has developed a way to do this starting with even the most___ 48___deserted areas. And the Miyawaki method is finding increasing___ 49___around the world.Dr Miyawaki's insight was to deconstruct and rebuild the process of ecological succession, by which ___50___land develops naturally into mature forest. Usually,the first arrival is grass, followed by small trees and,finally. larger ones.The Miyawaki method___51 ___some of the early phases and jumps directly to planting the kinds of species found in a mature wood.Dr Miyawaki has__52__the planting of more than 1,500 of these miniature forests,first in Japan,then in other parts of the world. Wherever they are planting,though,gardeners are not restricted to__53 __nature's recipe book to the letter. Miyawaki forests can be customized to local requirements. A popular choice__54__ is to include more fruit trees than a natural forest might support,thus creating an orchard that requires no maintenance.If your goal is to better your __55__surroundings,rather than to save the planet from global warming,then Dr Miyawaki might well be your man.41. A. thrive B. nourish C. displace D. raise42. A. assessment B. maintenance C. spread D. replacement43. A. release B. trap C. reflect D. dissolve44. A. attraction B. shadow C. interaction D. shade45. A. consumption B. coverage C. interval D. conservation46. A. blessed B. lined C. piled D. fascinated47. A. treatment B. obstacle C,warning D. solution48. A. unnoticed B. unpromising C. untested D. unfading49. A. criticism B. favor C. sponsor D. anxiety50. A. bare B. graceful C. faint D. mysterious51. A highlights B. skips C. improves D. pushes52. A. accessed B. spotted C. supervised D. ranked53. A. disturbing B. balancing C. following D. reducing54. A. for example B. in essence C. on the other hand D. after all55. A. suburban B. leisure C. scenic D. immediateSection BDirections: Read the following three passages. Each passage is followed by several questions or unfinished statements. For each of them there are four choices marked A,B,C and D. Choose the one that fits best according to the information given in the passage you have read.(A)From Marie Tussaud's Chamber of Horrors to Disneyland's Haunted Mansion(鬼屋)to horror-themed escape rooms,haunted house attractions have terrified and delighted audiences around the world for more than 200 years.These attractions turn out to be good places to study fear. They help scientists understand the body's response to fright and how we perceive some situations as enjoyably thrilling and others as truly terrible. One surprising finding;having friends close at hand in a haunted house might make you more jumpy,not less so.Psychologist and study co-author Sarah Tashjian,who is now at the University of Melbourne, and her team conducted their research with 156 adults,who each wore a wireless wrist sensor during their visit. The sensor measured skin responses linked to the body's reactions to stress and other situations. When the sensor picked up,for example,greater skin conductance —that is,the degree to which the skin can transmit an electric current —that was a sign that the body was more aroused and ready for fight or flight. In addition to this measure,people reported their expected fear (on a scale of 1 to 10)before entering the haunted house and their experienced fear (on the same scale)after completing the haunt.The scientists found that people who reported greater fear also showed heightened skin responses. Being with friends,Tashjian and her colleagues further found,increased physiological arousal during the experience,which was linked to stronger feelings of fright. In fact,the fear response was actually weaker when people went through the house in the presence of strangers.Other investigators have used haunted houses to understand how fear and enjoyment can coexist. In a 2020 study led by Marc Malmdorf Andersen,a member of the Recreational Fear Lab at Aarhus University in Denmark,scientists joined forces with Dystopia Haunted House. The Danish atraction includes such terrifying experiences as being chased by "Mr. Piggy",a large, chain-saw-wielding man wearing a bloody butcher's apron and pig mask. People between the ages of 12 and 57 were video recorded at peak moments during the attraction,wore heart-rate monitors throughout and reported on their experience. People's fright was tied to large-scale heart-rate fluctuations;their enjoyment was linked to small-scale ones. The results suggest that fear and enjoyment can happen together when physiological arousal is balanced "just right".56. Studing haunted house attractions helps scientists to learn about _____.A. the psychological effects of fear on individualsB. the history of horror-themed entertainmentC. the body's response to material rewardsD. the impact of technology on people's enjoyment57. How did Sarah Tashjian and her team conduct their research on haunted house experiences? A. By surveying participants.B. By analyzing historical records.C. By employing wireless wrist sensors.D. By using virtual reality simulations.58. What did Tashjian and her colleagues discover in their study?A. Being with fiends elevated level of physiological arousal.B. The fear reaction was stronger in the company of strangers.C. Psychological effect was unrelated to intensified feelings of fright.D. Those reporting lightened fear showed increased skin responses.59,It can be concluded from the 2020 study led by Marc Malmdorf Andersen that ____.A. fear and enjoyment can not happen at the same timeB. large-scale heart-rate fluctuations were linked to enjoymentC. the age of the participants was not related to the study's findingsD. fear and enjoyment can coexist under certain conditions(B)Is an electric vehicle right for you?Many people will ask themselvesthat question for the first time this year.Prices are falling,battery range is risingand mainstream brands are adding new EVs at a breakneck pace.Here are three things anybody seriously considering buying an EV should know:1. The price to install a 240v chargerAnybody who owns an electric vehicle needs a 240-volt charger at home. With one,you can recharge overnight,so you start every day with the equivalent of a full tank.Just a few years ago,home 240v EV chargers cost $2,500-$3,000,including installation,but prices have declined as competition grows with the number of EVs on the road.2. The time it takes to chargeAbout 80%of miles driven in EVs are powered by electricity charged at home,but you'll need to charge elsewhere occasionally. That's when charging time becomes a big deal,but how long it takes depends on a couple of factors.First,voltage from the charger. Getting 250 miles of range in seven hours from a 240v charger is fine when you're charging overnight at home,but it's a deal breaker if you're going 300 miles for a weekend getaway. In that case,you'll want to look for a 400v DC fast charger. They're not as common as 240v public chargers yet,but they're becoming more widespread.There's another factor:the on-board charger. It regulates how fast the battery can accept electricity. A vehicle with a higher-capacity on-board charger accepts electricity faster.3. Where to chargeGood route-planning apps will help you find chargers on a road trip.“Most people have no idea how many public charging stations are within,say,a 10-or 15- mile radius(半径)because they're small,people don't look for them or even don't know what to look for,and they're rarely signposted,"said journalist John Voelcker,who has studied EVs and charging exhaustively.4. On the horizonIf an EV doesn't meet your needs now, watch this space. They're coming closer,but large numbers of gasoline vehicles will remain in production for years. Beyond that,companies will keep making spare parts for oil-burners for decades.60. Which of the following statements is TRUE according to the passage?A. The price of installing a home EV charger has remained stable in the past few years.B. It's quite easy to identify the public charging stations with the help of striking signposts.C. Popular brands are introducing new EVs at an incredibly fast rate.D. An electric vehicle can't provide the same amount of energy as a completely filled fuel tank.61. The underlined phrase "watch this space" in the last paragraph probably means" _______ ”.A. give up the plan to purchase an EVB. make space for an EVC. find an alternative to EVD. keep an eye out for future developments62. This passage is mainly intended to _______ .A illustrate the factors charging time depends onB. offer advice on purchasing an electric vehicleC. look forward to the future of electric vehiclesL explain the reason for the falling prices of electric vehicles(C)Flinging brightly coloured objects around a screen at high speed is not what computers' central processing units were designed for. So manufacturers of arcade machines invented the graphics-processing unit (GPU),a set of circuits to handle video games' visuals in parallel to the work done by the central processor. The GPU's ability to speed up complex tasks has since found wider uses:video editing, cryptocurency mining and most recently,the training of artificial intelligence.AI is now disrupting the industry that helped bring it into being. Every part of entertainment stands to be affected by generative AI,which digests inputs of text,image,audio or video to create new outputs of the same. But the games business will change the most,argues Andreessen Horowitz,a venture-capital(VC)firm. Games interactivity requires them to be stuffed with laboriously designed content:consider the 30 square miles of landscape or 60 hours of music in “Red Dead Redemption 2”a recent cowboy adventure. Enlisting Al assistants to chum it out could drastically shrink timescales and budgets.AI represents an "explosion of opportunity"and could drastically change the landscape of game development. Making a game is already easier than it was:nearly 13,000 titles were published last year on Steam,a games platform,almostdouble the number in 2017. Gaming may soon resemble the music and video industries in which most new content on Spotify or YouTube is user-generated. One games executive predicts that small firms will be the quickest to work out what new genres are made possible by Al. Last month Raja Koduri,an executive at Intel,left the chip maker to found an Al-gaming startup.Don't count the big studios out,though. If they can release half a dozen high-quality titles a year instead of a couple,it might chip away at the hit-driven nature of their business,says Josh Chapman of Konvoy,a gaming focused VC firm. A world of more choices also favors those with big marketing budgets. And the giants may have better answers to the mounting copyright questions around Al. If generative models have to be trained on data to which the developer has the rights,those with big back-catalogues will be better placed than startups. Trent Kaniuga,an artist who has worked on games like "Fortnite",said last month that several clients had updated their contracts to ban Al-generated ant.If the lawyers don't intervene,unions might. Studios diplomatically refer to Al assistants as “co-pilots”,not replacements for humans.63. The original purpose behind the invention of the graphics-processing unit (GPU)was to______A. speedup complex tasks in video editing and cryptocurency miningB. assist in the developing and training of artificial intelligenceC. disrupt the industry and create new outputs using generative AID. offload game visual tasks from the central processor64. How might the rise of AI-gaming startups affect the development of the gaming industry?A. It contributes to the growth of user-generated content.B. It facilitates blockbuster dependency on big studios.C. It decreases collaboration between different stakeholders in the industry.D. It may help to consolidate the gaming market under major corporations.65. What can be inferred about the role of artificial intelligence in gaming?A. AI favors the businesses with small marketing budgets.B. AI is expected to simplify game development processes.C. AI allows startups to gain an edge over big firms with authorized data.D. AI assistants may serve as human substitutes for studios.66. What is this passage mainly about?A. The evolution of graphics-processing units (GPUs).B. The impact of generative AI on the gaming industry.C. The societal significance of graphics-processing units(GPUs).D. The challenges generative AI presents to gaming studios.Section CDirections: Read the following passage. Fill in each blank with a proper sentence given in the box. Each sentence can beTime to end Santa's 'naughty list'?Many of us have magical memories of Santa secretly bringing gifts and joy to our childhood homes —but is there a darker side to the beloved Christmas tradition?I was —and I'm happy to admit it —a loyal believer of Santa. I absolutely loved the magic of Christmas,especially Santa Claus,and my parents went above and beyond to encourage it. However,as I begin to construct my own Santa Claus myth for my daughter,I can't help but feel guilty. Could it undermine her trust in me?_____67______Backin1978,a study published in the American Journal of Orthopsychiatry(矫正精神医学)found that 85%of four-year-olds said they believed in Santa. In 2011,research published in the Journal of Cognition and Development found that 83%of 5-year-olds claimed to be true believers.I guess it's not all that surprising. _____68 _____He features in every Christmas TV show and movie. Each year the North American Aerospace Defence Command (NORAD)allows you to track Santa's journey on Christmas Eve. To reassure children during the pandemic in 2020,the World Health Organization issued a statement declaring that Santa was “immune”from Covid 19. And it's precisely this effort on behalf of parents,and society in general,to create such seemingly overwhelming evidence for the existence of Santa Claus that David Kyle Johnson,a professor of philosophy at King's College in Pennsylvania,describes as 'The Santa Lie' in his book The Myths That Stole Christmas. He highlights how we don't simply ask children to imagine Santa,but rather to actually believe in him. _____69 _____The 'Santa lie' can reduce trust between a parent and a child. _____70 _____It is the creation of false evidence and convincing kids that bad evidence is in fact good evidence that discourages the kind of critical thinking we should be encouraging in children in this era. “The ‘Santa lie' is part of a parenting practice that encourages people to believe what they want to believe,simply because of the psychological reward,”says Johnson. “That's really bad for society in general. ”IV. Summary WritingDirections: Read the following passage. Summarize the main idea and the main point(s)of the passage in no more than 60 words. Use your own words as far as possible.Exploring the Appeal of VintageToday,the term“vintage”applies to almost everything. Vintage is more recent than an antique (古董)which is defined as 100 years old or more. It basically means reviving something old- fashioned or filled with memories. For an object to be considered vintage,it must be unique and genuine enough to retain at least some of its original charm.We buy vintage because it creates a sense of personal connection for us:it speaks to our childhood memories and that feels good. We also buy vintage because we're rebels. Vintage is a protest against modern mainstream culture. In an age of technology,buying vintage is a refuge from our fast-paced,high-tech world. We want our children to make the most of their creativity and know how to entertain themselves without electronic gadgets. Ironically,early video games are now considered vintage.Of all the vintage objects,vintage toys are forever attractive for both adults and children. Although some toys have emotional value,others have high market value and are expensive to collect. Vintage toys that were made in small quantities often bring a higher value than those that were mass produced. That means,if you own one of the 2,000 “Peanuts”royal blue beanie baby elephants that were manufactured with a darker blue coat than originally intended,you might have something valuable on your hands. In fact,due to a manufacturer error,this is the most collectible beanie baby around —and worth about f3,000.If you're motivated and feeling lucky,you can find deals on vintage toys by browsing charity shops,secondhand stores,community centers,flea markets and garage sales. You never know what kind of treasures are hiding at the bottom of a mixed box in someone's basement,garage or attic.第Ⅱ卷(共40分)V. TranslationDirections: Translate the following sentences into English. using the words given in the brackets.72. 他在升旗仪式上的演讲得到了高声喝彩。

Infra-red detection apparatus

专利名称：Infra-red detection apparatus发明人：Grant, John Thomas申请号：EP92309235.7申请日：19921009公开号：EP0537024A1公开日：19930414专利内容由知识产权出版社提供专利附图：摘要：Apparatus for the detection of infra-red radiation comprises a passive infra-red sensor (16), a focusing reflector (20) constructed and arranged to focus infra-redradiation received by the apparatus from a first range of distances from the apparatus,on the sensor (16) , and a focusing refractor (14) constructed and arranged to focus infra-red radiation received by the apparatus from a second range of distances from the apparatus, on the sensor (16), the second distance range encompassing distances shorter than the first distance range. The refractor may be a Fresnel lens (14) or an array of Fresnel lenses (32, 33, 34) formed in a polyethylene window (12) through which the radiation is transmitted. The reflector (20) may be a concave reflector and a second plane reflector (22) may be included to produce a more compact construction.申请人：SECURITY ENCLOSURES LIMITED地址：30 Green Lane Lower Kingswood, Surrey KT20 6TL GB国籍：GB代理机构：Blatchford, William Michael更多信息请下载全文后查看。

Sex and Society

PIONEERSex and SocietyAn interview with Pan Suiming, China’s leading sex sociologist 对话性社会学家潘绥铭COULD YOU TELL US A BIT ABOUT YOUR FIELD’S CURRENT STATUS IN CHINA AND YOUR PLACE IN IT?First, the phrasing should be correct; it’s not sexology, as my research field is not sexology, but rather a social study on sexuality, or sex-sociology. In this field in China, there are, more or less, 10 researchers and 20 to 30 scholarly publications. My research mainly focuses on two parts: one is Chinese people’s sexual behavior, sexual relations, and ideas about sex, chiefly including three nationwide surveys; the other is researchabout red-light districts, female sex workers, and the sex industry.HOW DID YOUR RESEARCH GROUPBEGIN INVESTIGATIONS INTO RED-LIGHT DISTRICTS?In the beginning, you needed an introduction, a guide. To undertake social investigations, a guide is necessary. Unless you are in your hometown or in your own family, when you arrive in a strange place, you need a guide. In general, the mami (procuress) is the reasonable person. Why? The mami has lots of social experience, they meet lots of people, from government officials togang leaders. What kind of personIn 1968, in the midst of the Cultural Revolution, Pan Suiming went to work on a state-run farm in Heilongjiang. From there Pan worked his way up to a professor at Renmin University in 1984, where, in his second year, he offered a course on sexual sociology, the first of its kind in China and an event that sparked headlines and conversation around the nation. Since 1997, Mr. Pan has been going to red-light districts to investigate the underground Chinese sex industry, eventually publishing Existence and Absurdity (《存在与荒谬》), in which he wrote “Prostitutes are human beings, and research about them should be on a basis of equality and respect.” In 2013, Pan, together with his colleague Huang Yingying, published The Change of Sex: Chinese People’s Sex Lives in the 21st Century (《性之变：21世纪中国人的性生活》), which discusses the results and analysis of three surveys on sex in China. Today, Pan is considered one of the leading experts in the field of sexual sociology in China and is still a professor at Renmin University.88wouldn’t she meet? So, they aren’t afraid of you and are easy to get in touch with. Furthermore, you should treat them honestly; Chinese people care if they’re being treated respectfully and honestly. I show them my ID card, my work card, and tell them my telephone number. Some of them even chat with my wife. No problem, I have nothing to hide. If you tell them the whole situation, most of them will dismiss any misgivings about the investigation.WHAT MISGIVINGS MIGHT THEY HAVE?The first question is whether or not you are a journalist; they are fearful of journalists. Second, they ask if you are police, but the police don’t often do things that way. So, if they trust you are not a journalist, you set their mind at ease. If they have misgivings, they will ignore you. In this situation, you just give up and find another. The success rate is about 50 percent. We wrote about 13 red-light districts. However, we attempted more than 20. Some of them, we couldn’t carry on because we couldn’t find a proper guide. The other reasons for quitting were severe local anti-Copyright ©博看网. All Rights Reserved.pornography campaigns, other times the red-light districts were just too small.HOW DID YOU CONTINUE YOUR INVESTIGATIONS AFTER OBTAINING INFORMATION FROM THE MAMI?We chatted with the girls. We didn’t interview them, we chatted with them. I used my real identity, so that I could see all sides of their lives, except their work. Some survey companies pretend to be customers—that’s meaningless. When pretending to be interested in their work, you can only “investigate” the matter of prostitution, not prostitutes. They don’t treat thesex workers as human. Femalesex workers are real people with a normal life besides their work.In addition, what informationcan you get as a client? Only theprice. Do you really need anotheridentity to ask? Everyone in thered-light district knows the price.It’s common sense, when you buysomething in a store, what do youask the store clerks? How much isit? Where is it from? How about thequality? This is what you ask, right?It would be stupid to ask themabout their personal life or family.WHAT DO YOU THINK ABOUT THELEGALIZATION OF PROSTITUTION?HOW WOULD YOU DEAL WITHPROBLEMS IN THE SEX INDUSTRY?Don’t arrest prostitutes. Don’ttake them into custody. ThePan SuimingProfession: Professor ofsexual sociology and founderof the Institute of Sexuality andGender at Renmin UniversityNationality: ChinesePIONEER PROFILEgovernment can manage them, taxthem, charge health inspection fees,and perform physical examinations.Management is necessary; in otherwords, make it part of society.Decriminalization or legalization areEnglish phrases, which are suitablefor English discourse. In Chinese, itdoesn’t make much sense. In Chinese,socialization is better. To socialize itmeans to treat it as a social problem.Is it a problem? Indeed, it’s a problem.However, it’s a social problem. Ratherthan by means of coercion, it shouldbe solved by management. HongKong uses One Floor One; that is,a prostitute in one separate room.Only one man can go in at a time. Inthis situation, if there is a conflictbetween client and prostitute, whowould win? When a man and a womencome to blows, the result depends.She might be able to beat the clientin her environment with precautionsin place. Under systems such as theOne Floor One, a prostitute in a room,nobody can interfere, not even thepolice. So, their safety will improve.Self defense such as pepper spray andstun batons can be put to use. Takea look at what happens now: somemen go out looking for prostituteswithout any money to spend, even tothe extent that they rob these girls.These girls just endure this. Why?Their occupation is considered illegal.If they report it to the police, they willThe Change of Sex: Chinese People’s Sex Lives in the 21st Century, 2013Copyright©博看网. All Rights Reserved.Issue 3 /201489be arrested. One Floor One has been going on for about 140 years, and it is the best match for Chinese conditions.THERE IS A PUBLIC VOICE SUGGESTING THE LEGALIZATION OF RED-LIGHT DISTRICTS. WHAT DO YOU THINK? There is a huge problem with the legalization of red-light districts. For instance, if you demarcate the campus of Renmin University tobe a red-light district, will all the xiaojie (prostitutes) come? If they reluctantly came, do you think Chinese clients would dare? The nearby the campus gates wouldbe hounded by journalists and paparazzi, with cameras on 24-7.In this situation, how can you earn money as a prostitute? No work,no food. They would run from this red-light district. Then, the police would have to catch them andtake them back to the campus. Hence, the legalization of red-light districts, actually, creates a kind of concentration camp. So, there is a complete difference between the legalization of red-light districts and the legalization of the sex industry.CAN YOU TELL US A BIT ABOUT YOUR THREE SURVEYS?We launched three surveys on Chinese people’s sex lives in 2000, 2006, and 2010. The second time would have been in 2005, butwe had to delay due to funding problems. These surveys were the first random sampling surveysin this field of research, taking place on literate Chinese people throughout the country, aged from 18 to 61. We will continue the project in 2015.WAS IT DIFFICULT TO DEVELOP THIS SURVEY?Actually, these surveys were more difficult than the red-light district investigations. It’s a randomsampling survey, and there are2,742 county units all over thecountry. So, we randomly took 120samples (county units), then fromthese 120 samples, we took onevillage from the county. If it was ina city, for instance, Haidian Districtis a county unit. We would take oneresident community as a sample.The difficulty is that when we arriveat the residents’ community, we stillcould not recruit people to take partin our studies, so we had to ask theresidents’ committee for supportand help. After we find intervieweeswith the residents’ committee’shelp, we inform them that this is aninvestigation about sex, and uponhearing this, many refuse to help.This is the first response: somereject it immediately. The secondresponse happens after fixing thetime and the place, in a separateroom, with only the interviewerand interviewee. The interviewershould clearly declare that thequestionnaire will include matterspertaining to sexual relationshipsand privacy. If they refused toanswer, then, nevermind—a fewquit after that. The success rate isabout 70 percent. This is the highestrate in the world. In America, it’s52 percent. Why is the rate so high?Firstly, in China, religion doesn’thave too much impact on people’slife. Secondly, Chinese people areactually open-minded about sex.Chinese maintain a wall of silencein public, but if you put them intoa room, only two people, theylike to talk. In addition, this is aquestionnaire with a computer, nota face-to-face interview, so they feeltheir privacy is protected.HOW DO YOU MOBILIZE THEPARTICIPANTS TO TAKE PART?The first sentence we say tomobilize them is, “Do you want toknow Chinese people’s positionon this matter?” Usually, theiranswer is yes. So, some peoplebegin to understand, “Ah, I shouldtake part in this. If everyonerejects, how can we know?” Thenwe tell them: “You came becausethe residents’ committee askedyou to come, but we don’t knowwho you are. You don’t need totell us your name, address, ortelephone number. On the otherside, the residents’ committeeknow you take part, but theydon’t know your numbers. This isdouble blind test.” Some youngmen are still skeptical, so theycheck for video or audio in theroom. I tell them to double checkall they like so that there are nomisgivings. Moreover, there isanother group: in the beginning,they hesitate to join in, butthey are very curious about ourprogram. They will ask us whatkinds of questions are in it. Wetell them that we can’t disclosethe details and that they’ll onlyknow if they participate. So, theycome, actually—they justify it withtheir curiosity, increasing theoverall successful response rate.IN RECENT YEARS, THE TOPICOF SEX HAS BEEN DISCUSSEDMORE AND MORE IN THE MEDIA.YOU SEEM TO BE THE GO-TO-GUYFOR THIS SUBJECT. DO YOU HAVEANYTHING TO SAY ABOUT THE MEDIAATTENTION?People are not paying attentionto me; they pay attention to sex.In the 1980s, almost every day,I would meet journalists, toomany journalists—now it’s muchless. The media at that time wasmuch more open than now. Allthe topics that are discussedright now were discussed inthe 1980s, except the topic ofhomosexuality—people didn’t talkabout that back then.-ALICIA ZHANG (张华阳)Copyright©博看网. All Rights Reserved.90。

鸢尾素在脓毒症大鼠头端延髓腹外侧区的心血管效应

㊀㊀基金项目:甘肃省自然科学基金资助项目(17JR5RA263);江苏省苏州高新区医疗卫生科技计划重点项目(2019Z003);江苏省苏州高新区人民医院科学创新基金资助项目(SGY2020D01)作者单位:215000㊀苏州高新区人民医院麻醉科(赫曼㊁杨毅),普外科(徐时㊁柴琛);730000㊀兰州大学第一医院普外科(杜杰㊁杨磊㊁李斌)通讯作者:柴琛,主任医师,教授,硕士生导师,电子信箱:chaich@鸢尾素在脓毒症大鼠头端延髓腹外侧区的心血管效应赫㊀曼㊀杜㊀杰㊀杨㊀磊㊀李㊀斌㊀杨㊀毅㊀徐㊀时㊀柴㊀琛摘㊀要㊀目的㊀研究鸢尾素在脓毒症大鼠头端延髓腹外侧区(RVLM)的心血管效应㊂方法㊀将15只雄性SD 大鼠随机分为空白对照组㊁假手术组和脓毒症组,每组5只,免疫组化法检测鸢尾素在RVLM 表达情况㊂以盲肠结扎穿刺法建立大鼠脓毒症模型,将造模成功的28只雄性SD 大鼠随机分为4组,每组7只,对照组RVLM 预先注射人工脑脊液;实验组分别在RVLM 注射10㊁100和1000pmol 鸢尾素,信号记录分析仪记录大鼠的血压和心率㊂结果㊀脓毒症大鼠RVLM 鸢尾素表达明显降低(P <0.05)㊂单侧RVLM 微量注射鸢尾素后血压升高㊁心率加快(P <0.05)㊂结论㊀脓毒症时鸢尾素在RVLM 表达降低导致心血管作用减弱,鸢尾素在中枢的水平变化与脓毒症病理过程相关㊂关键词㊀鸢尾素㊀脓毒症㊀头端延髓腹外侧区㊀血压㊀心率中图分类号㊀R631㊀㊀㊀㊀文献标识码㊀A㊀㊀㊀㊀DOI ㊀10.11969/j.issn.1673-548X.2021.03.024Cardiovascular Effects of Irisin in the Rostral Ventrolateral Medulla of Septic Rats.㊀He Man ,Du Jie ,Yang Lei ,et al.Department of An-esthesiology ,Peopleᶄs Hospital of SND ,Jiangsu 215000,ChinaAbstract ㊀Objective ㊀To study the cardiovascular effects of irisin within the rostral ventrolateral medulla (RVLM)in sepsis rats.Methods ㊀Fifteen male SD rats were randomly divided into control group,sham operation group and sepsis group.The expression of irisin in the RVLM was detected by immunohistochemistry.Septic rat model was established with cecal ligation and puncture (CLP)method.Twenty -eight male SD rats were randomly divided into four groups equally.The control group rats were pre -injected with artificial cere-brospinal fluid (aCSF)in RVLM,and the rats of experimental groups were micro -injected in RVLM with different consentration irisin by10,100,1000pmol,respectively.The blood pressure (BP)and heart rate (HR)were recorded by the Signal recording analyzer.Results The expression of irisin the RVLM of rats in the sepsis group was significantly decreased compared with the normal control group (P <0.05).Unilateral microinjection of irisin into the RVLM significantly incrceased BP and HR of septic rats (P <0.05).Conclusion ㊀In the RVLM of sepsis rats,irisin produced hypertension and accelerated heart rate.Irisin is probably involved in the pathological process ofsepsis by low expression in the RVLM.Key words ㊀Irisin;Sepsis;Rostral ventrolateral medulla (RVLM);Blood pressure (BP);Heart rate (HR)㊀㊀脓毒症(sepsis)是宿主对感染的反应失调引起的危及生命的器官功能障碍,尽管国内外已经对脓毒症的病理生理学有了深入的研究,但目前仍没有十分有效的治疗方法,在发达国家每年约有530万例脓毒症死亡[1,2]㊂脓毒症可引起低血压休克,中枢的头端延髓腹外侧区(RVLM)是调控中枢心血管活动的关键部位,位于RVLM 的前交感神经元产生交感冲动,最终决定心输出量和血管阻力[3]㊂有研究表明鸢尾素在外周有调节血压作用,但脓毒症时鸢尾素在中枢RVLM 的作用未见报道[4]㊂本研究通过免疫组织化学检测鸢尾素在脓毒症大鼠RVLM 中表达的水平,并在中枢RVLM 区域微量注射鸢尾素,以观察其对心血管效应的调控,探讨鸢尾素是否通过RVLM 参与脓毒症的病程,为临床防治脓毒症寻找新的思路和实验依据㊂材料与方法1.主要实验试剂与仪器:鸢尾素购自德国Phoe-nix Pharmaceuticals 公司;兔抗大鼠鸢尾素多克隆抗体购自英国Abcam 公司;RM6250型生物信号记录系统购自成都仪器厂;XTL -3500型解剖显微镜购自上海光学仪器厂;大鼠脑MP -805型立体定位仪同购自深圳沃瑞德科技有限公司;小动物DW -3000型呼吸机购自上海嘉鹏科技有限公司㊂2.实验动物及分组:清洁级成年雄性SD 大鼠60㊃001㊃只,体质量250~300g,购自甘肃中医药大学实验动物中心[实验动物许可证号:SCXK (甘)2017-0001]㊂实验分为两部分,每部分均采用数字表法随机进行分组㊂(1)鸢尾素在脓毒症大鼠RVLM 的表达水平:共15只雄性SD 大鼠分为正常对照组㊁假手术组和脓毒症模型组,每组5只㊂(2)鸢尾素在脓毒症大鼠RVLM 产生的心血管效应:造模成功的28只雄性脓毒症SD 大鼠采用数字表法随机分为4组,每组7只,对照组RVLM 预先给予注射人工脑脊液;实验组分别在RVLM 注射10㊁100和1000pmol 鸢尾素,观察并记录鸢尾素在RVLM 产生的心血管效应㊂药物剂量参考有关文献报道[5,6]㊂3.建立脓毒症大鼠模型:适应性饲养大鼠5天,室温条件下自由进食水,昼夜交替㊂术前禁食12h,饮水不限,参照笔者前期研究[7]以盲肠结扎穿刺法(CLP )建立大鼠脓毒症模型㊂2%戊巴比妥钠(40mg /kg)腹腔注射麻醉,取腹部正中1.5cm 的竖行切口,进腹后游离盲肠系膜,在盲肠末端中外1/3处丝线结扎,用16号针头于结扎盲肠远端横向贯穿两次,用手轻轻挤压盲肠使少量肠内容物溢出,还纳肠管并分层缝合腹壁切口㊂假手术组在开腹后只提出盲肠并翻动,然后关腹㊂手术操作后给予大鼠腹部皮下注射30ml /kg 0.9%NaCl 注射液,以补充大鼠术中体液损失㊂术后将大鼠置于25ħ的环境中,并给予充足的饲料和饮水㊂大鼠脓毒症模型制作成功的表现为:精神萎靡㊁竖毛㊁畏寒㊁眼角分泌物增多㊂4.大鼠脑组织免疫组化:将大鼠脑组织石蜡切片进行脱蜡和水化,用柠檬酸钠进行热修复,PBS 缓冲液冲洗后以3%的过氧化氢封闭15min,加入正常的山羊血清在室温孵育,滴加一抗(1ʒ200)4ħ冰箱过夜,37ħ水浴箱复苏后PBS 缓冲液洗涤,滴加二抗后37ħ的水浴箱孵育,PBS 洗涤,滴加SP 试剂盒中辣根过氧化物酶标记的链霉卵白素工作液,水浴箱孵育后DAB 显色(1ʒ20),显微镜下观察显示为棕黄色时终止反应,苏木精复染,梯度乙醇脱水后封片㊂5.大鼠中枢核团微量注射及定位:将大鼠成功麻醉后行气管插管,进行右侧股静㊁动脉插管,动脉连接到压力换能器以记录血压和心率㊂俯卧位将大鼠头部固定在脑立体定位仪上,开颅暴露延髓,待大鼠血压和心率稳定后进行注射㊂参考脑立体定位图谱以大鼠的延髓栓部为零点,向头端移动2.5~2.9mm,旁开1.6~2.0mm,向下进针深度3.0~3.4mm㊂用玻璃微电极自制三通玻璃微电极灌注鸢尾素100nl,给药时间5~10s㊂RVLM 微量注射后,在同一给药部位注射2%滂胺天蓝染色,将大鼠脑组织切片,对照脑立体定位图谱验证注射部位(图1)㊂以上所有手术操作方法参考相关文献[8,9]㊂图1㊀大鼠延髓冠状切面图RVLM 注射部位定位图㊀㊀㊀6.统计学方法:采用SPSS 22.0统计学软件对数据进行处理分析,计量资料以均数ʃ标准差(x ʃs )表示㊂大鼠心率和血压均统计给药后所产生的最大值,采用重复测量资料方差分析的方法对同组微量注射后不同时间点的血压和心率进行分析;采用Student -Newman -Keuls (SNK )检验和单因素方差分析比较多组间的差异,以P <0.05为差异有统计学意义㊂㊃101㊃结㊀㊀果1.鸢尾素在RVLM的表达水平:免疫组化法检测在RVLM鸢尾素表达水平,黄色颗粒为表达阳性㊂与正常对照组比较,鸢尾素在脓毒症组中低表达(P<0.05);假手术组与正常对照组比较表达相似(图2)㊂图2㊀鸢尾素在RVLM的表达(HE染色,ˑ200) A.正常组;B.假手术组;C.脓毒症组;D.与正常对照组比较,∗P<0.05㊀㊀2.鸢尾素在RVLM产生的心血管效应:脓毒症模型大鼠单侧RVLM微量注射人工脑脊液对大鼠的血压和心率没有明显影响(P>0.05),微量注射鸢尾素(10㊁100㊁1000pmol)可产生剂量依赖性加快心率和升高血压的作用,其中低剂量㊁中剂量以及高剂量组血压均显著升高(P<0.05),高剂量组心率显著升高(P<0.05)㊂鸢尾素在RVLM所产生的心血管效应约在给药后10s后产生,10~30s左右升高至最高点,持续约120~200s,然后逐渐下降恢复正常水平(图3)㊂讨㊀㊀论近年来,脓毒症的发生率和病死率在逐渐增加㊂国际指南提出了集束化的综合治疗方案,但结果仍不尽人意[10,11]㊂若脓毒症发展为脓毒性休克在临床治疗困难,病死率极高㊂本研究发现,脓毒症时一些小分子物质在RVLM起到了调控心血管的作用[9,12]㊂RVLM主要接受来自外周多种感受器信息传入,以及中枢孤束核(NTS)等心血管调节相关核团的信息传入,并将整合后的信息传至交感节前神经元,从而在维持交感静息张力,在调节各种心血管反射活动中发挥作用[13]㊂鸢尾素是近年来发现的由运动诱导产生的一种肌肉因子㊂在过氧化物酶增殖受体γ激活因子-1α(PCG-1α)调控下,Ⅲ型纤连蛋白组件蛋白5 (FNDC5)基因转录激活,FNDC5经剪切㊁修饰㊁分泌后入血,形成的多肽片段为鸢尾素[14]㊂鸢尾素最初被发现是一种肌动蛋白,对糖尿病㊁病理性肥胖等代谢性疾病具有保护作用,近年来还发现具有抗炎和抗氧化等作用[15,16]㊂鸢尾素有望成为炎性疾病诊断的生物学标志物和治疗的靶点,具有广阔的研究前景㊂本研究结果表明,脓毒症大鼠RVLM中鸢尾素的表达显著降低,这提示内源性鸢尾素可能参与了脓毒症的病理过程㊂鸢尾素在脓毒症大鼠中枢部位的表达变化尚未见报道,但有研究者发现原发性高血压模型大鼠中枢微量注射鸢尾素可以显著增加下丘脑神经元的c-Fos蛋白表达,表明中枢鸢尾素水平与大鼠心血管活动相关[5]㊂为进一步探讨鸢尾素是否为脓毒症低血压的始动因素,本研究以不同浓度的鸢尾素进行了RVLM 微量注射,结果表明脓毒症模型大鼠单侧RVLM微量注射人工脑脊液对大鼠的血压和心率没有明显影响(P>0.05);微量注射鸢尾素(10㊁100㊁1000pmol)可产生剂量依赖性加快心率和升高血压的作用,鸢尾㊃201㊃图3㊀RVLM单侧微量注射鸢尾素对大鼠血压和心率的影响A~D.RVLM单侧微量注射人工脑脊液(aCSF)㊁鸢尾素(10㊁100㊁1000pmol)后脓毒症大鼠的心血管效应;E~F.与aCSF组比较,∗P<0.05㊀素在RVLM所产生的心血管效应约在给药后10s后产生,10~30s左右升高至最高点,持续约120~ 200s,然后逐渐下降恢复正常水平㊂这表明鸢尾素在脓毒症早期可能参与了脓毒性休克的血压下降过程㊂有研究显示,大鼠第三脑室微量注射鸢尾素可以显著升高血压,而对原发性高血压大鼠静脉给予鸢尾素时则产生与之相反的降压作用,提示鸢尾素可能通过激活下丘脑神经元来生产血管加压素,从而达到升高血压的效果[5]㊂有研究表明鸢尾素通过AMPK-Akt-eNOS-NO信号通路在外周显示出降压效果,然而鸢尾素在中枢产生升压作用的机制尚未见相关报道[17]㊂本课题组将进一步研究鸢尾素在脓毒症大鼠中枢RVLM调控心血管活动的作用机制㊂参考文献1㊀Singer M,Deutschman CS,Seymour CW,et al.The third interna-tional consensus definitions for sepsis and septic shock(Sepsis-3) [J].JAMA,2016,315(8):801-8102㊀Fleischmann C,Scherag A,Adhikari NK,et al.Assessment of global incidence and mortality of hospital-treated sepsis.Current estimates and limitations[J].Am J Respirat Crit Care Med,2016,193(3): 259-2723㊀Lai CC,Fan Z,Yuan LY,et al.Roles of cocaine-and ampheta-mine-regulated transcript peptide in the rostral ventrolateral medulla in cardiovascular regulation in rats[J].Brain Res,2019,1710(5): 117-1244㊀Jiang M,Wan F,Wang F,et al.Irisin relaxes mouse mesenteric ar-teries through endothelium-dependent and endothelium-independ-ent mechanisms[J].Biochem Biophys Res Commun,2015,468㊃301㊃(4):832-8365㊀Zhang W,Chang L,Zhang C,et al .Central and peripheral irisin dif-ferentially regulate blood pressure[J].Cardiovasc Drugs Ther,2015,29(2):121-1276㊀Ye L,Xu M,Hu M,et al .TRPV4is involved in irisin -induced en-dothelium -dependent vasodilation [J].Biochem Biophys Res Com-mun,2018,495(1):41-457㊀彭超,乔玮,庞众多,等.脓毒症时硫化氢对大鼠下丘脑-垂体-肾上腺轴应答的影响[J].中国急救医学,2016,36(11):975-9798㊀Qiao W,Yang L,Li XY,et al .The cardiovascular inhibition func-tions of hydrogen sulfide within the nucleus tractus solitarii are media-ted by the activation of KATP channels and glutamate receptors mech-anisms[J].Die Pharmazie,2011,66(4):287-2929㊀李斌,柴琛,鲁彦,等.头端延髓腹外侧区内二氧化硫对麻醉大鼠血压和心率的影响[J].中华高血压杂志,2013,21(3):272-27810㊀McPherson D,Griffiths C,Williams M,et al .Sepsis -associatedmortality in England:an analysis of multiple cause of death data from2001to 2010[J].BMJ Open,2013,3(8):e00258611㊀Kaukonen KM,Bailey M,Suzuki S,et al .Mortality related to severesepsis and septic shock among critically ill patients in Australia andNew Zealand,2000-2012[J].JAMA,2014,311(13):1308-131612㊀Xie FJ,Chai C,Zhu P,et al .The cardiovascular functions of salusin -beta mediated by muscarinic receptors,glutamate receptors or L -typecalcium channels within the rostral ventrolateral medulla of rats[J].Microsc Res Tech,2017,80(7):812-81913㊀Dempsey B,Le S,Turner A,et al .Mapping and analysis of the con-nectome of sympathetic premotor neurons in the rostral ventrolateral medulla of the rat using a volumetric brain atlas [J ].Fron Neural Circ,2017,11(3):1-1614㊀Bostrom P,Wu J,Jedrychowski MP,et al .A PGC1-alpha -de-pendent myokine that drives brown -fat -like development of whitefat and thermogenesis[J].Nature,2012,481(7382):463-46815㊀Kelly DP.Medicine.irisin,light my fire[J].Science,2012,336(6077):42-4316㊀Zhang D,Xie T,Leung PS.Irisin ameliorates glucolipotoxicity -as-sociated β-cell dysfunction and apoptosis via AMPK signaling andanti -Inflammatory actions [J ].Cell Physiol Biochem,2018,51(2):924-93717㊀Fu J,Han Y,Wang J,et al .Irisin lowers blood pressure by improve-ment of endothelial dysfunction via AMPK -Akt -eNOS -NO path-way in the spontaneously hypertensive Rat [J].J Am Heart Assoc,2016,5(11):e003433(收稿日期:2020-11-10)(修回日期:2020-11-15)㊀㊀作者单位:221004㊀徐州医科大学研究生院(石程程㊁张锦㊁黄小雨);221002㊀徐州医科大学附属医院神经内科(肖成华);261031㊀潍坊医学院附属医院神经内科(王炎强)通讯作者:肖成华,电子信箱:chenghuaxiaoxzbj@血清Hcy 、NLR 和PLR 水平与急性脑梗死患者颈动脉粥样硬化斑块稳定性及脑梗死复发的关系石程程㊀张㊀锦㊀黄小雨㊀肖成华㊀王炎强摘㊀要㊀目的㊀探讨血清同型半胱氨酸(Hcy)㊁中性粒细胞与淋巴细胞比值(neutrophil -to -lymphocyte ratio,NLR)和血小板与淋巴细胞比值(platelet -to -lymphocyte ratio,PLR)与急性脑梗死(acute cerebral infarction,ACI)患者颈动脉粥样硬化斑块稳定性及脑梗死复发的关系㊂方法㊀纳入急性脑梗死患者173例,根据颈动脉粥样硬化斑块稳定性分为稳定组(90例)和不稳定组(83例),另选取无颈动脉斑块形成的健康体检者76例为对照组㊂随访6个月,比较斑块稳定组及不稳定组中脑梗死复发情况㊂分析血清Hcy㊁NLR㊁PLR 与斑块稳定性的关系,并做影响脑梗死复发的因素分析㊂结果㊀不稳定斑块组血清Hcy㊁NLR㊁PLR 水平明显高于稳定斑块组及对照组(P <0.05),稳定斑块组血清Hcy㊁NLR㊁PLR 水平明显高于对照组(P <0.05)㊂Logistic 回归分析显示,Hcy㊁PLR㊁NLR 水平是影响斑块不稳定的危险因素;随访结果显示斑块稳定组脑梗死复发率明显低于斑块不稳定组(P <0.05),且复发时间明显高于斑块不稳定组(P <0.05)㊂多因素COX 回归分析显示高血压㊁Hcy㊁NLR㊁PLR㊁斑块不稳定是影响脑梗死复发的危险因素㊂结论㊀血清Hcy㊁NLR㊁PLR 水平与颈动脉粥样硬化斑块的形成及稳定性相关,且对脑梗死复发有一定预测价值㊂关键词㊀急性脑梗死㊀颈动脉粥样硬化斑块㊀复发㊀同型半胱氨酸㊀中性粒细胞与淋巴细胞比值㊀血小板与淋巴细胞比值中图分类号㊀R743.3㊀㊀㊀㊀文献标识码㊀A㊀㊀㊀㊀DOI ㊀10.11969/j.issn.1673-548X.2021.03.025㊃401㊃。

Differences_in_degree,_differences_in_kind__.9

Differences in degree,differences in kind:Characterizing lunginjury in traumaBenjamin M.Howard,MD,MPH,Lucy Z.Kornblith,MD,Carolyn M.Hendrickson,MD,MPH, Brittney J.Redick,Amanda S.Conroy,Mary F.Nelson,RN,MP A,Rachael A Callcut,MD,MSPH, Carolyn S.Calfee,MD,MAS,and Mitchell Jay Cohen,MD,San Francisco,California BACKGROUND:Acute lung injury following trauma remains a signiﬁcant source of morbidity and mortality.Although multiple trauma studies have used hypoxemia without radiographic adjudication as a surrogate for identifying adult respiratory distress syndrome(ARDS)cases,the differences between patients with hypoxemia alone and those with radiographically conﬁrmed ARDS arenot well described in the literature.We hypothesized that nonhypoxemic,hypoxemic,and ARDS patients represent distinctgroups with unique characteristics and predictors.METHODS:Laboratory,demographic,clinical,and outcomes data were prospectively collected from621intubated,critically injured patients at an urban Level1trauma center from2005to2013.Hypoxemia was deﬁned as Pa O2/FIO2ratio of300or lower.ARDS was adjudicated using Berlin criteria,with blinded two-physician consensus review of chest radiographs.Groupcomparisons were performed by hypoxemia and ARDS status.Logistic regression analyses were performed to separatelyassess predictors of hypoxemia and ARDS.RESULTS:Of the621intubated patients,64%developed hypoxemia;46%of these hypoxemic patients developed ARDS by chest ra-diograph.Across the three groups(no hypoxemia,hypoxemia,ARDS),there were no signiﬁcant differences in age,sex,orcomorbidities.However,there was an increase in severity of shock,injury,and chest injury by group,with correspondingtrends in transfusion requirements and volume of earlyﬂuid administration.Outcomes followed a similar stepwise pattern,with pneumonia,multiorgan failure,length of intensive care unit stay,number of ventilator days,and overall mortality highestin ARDS patients.In multiple logistic regression,early plasma transfusion,delayed crystalloid administration,body massindex,and head and chest injury were independent predictors of hypoxemia,while head and chest injury,early crystalloidinfusion,and delayed platelet transfusion were independent predictors of ARDS.CONCLUSION:Hypoxemia and ARDS exist on a spectrum of respiratory dysfunction following trauma,with increasing injury severity proﬁles and resuscitation requirements.However,they also represent distinct clinical states with unique predictors,whichrequire directed research approaches and targeted therapeutic strategies.(J Trauma Acute Care Surg.2015;78:735Y741.Copyright*2015Wolters Kluwer Health,Inc.All rights reserved.)LEVEL OF EVIDENCE:Prognostic and epidemiologic study,level III.KEY WORDS:ARDS;lung injury;hypoxemia;platelet transfusion;crystalloid.T rauma is the leading cause of death in the young world-wide,1with a characteristic distribution of immediate,early, and delayed mortality.2,3Late mortality is characterized by dysregulated systemic inﬂammation leading to multiple-organ failure,and lung dysfunction has been shown to play a central role in this process.4Although some measure of posttraumatic lung injury may be mitigated by the implementation of lung-protective ventilation strategies and the adoption of more judi-cious transfusion practices,5Y7the incidence of adult respiratory distress syndrome(ARDS)in severely injured trauma patients remains signiﬁcant.8,9Independent of underlying illness severity, the development of ARDS has been associated with major in-creases in morbidity,and up to a nearly threefold increase in mortality.10Since its initial description by Ashbaugh et al.in1967, ARDS has been deﬁned and redeﬁned several times,with di-agnostic criteria evolving to accommodate improved under-standing of both underlying pathophysiologic processes and broader epidemiologic trends.11,12Through multiple iterations, the deﬁnition of ARDS has included a combination of both acute hypoxemia and radiographic evidence of pulmonary edema,in the absence of cardiogenic causes.13While several studies have investigated risk factors for the development of ARDS in trauma, the differences between trauma patients with hypoxemia alone and those who develop radiographically conﬁrmed ARDS have not been well studied.14Y17In fact,multiple recent trauma studies have intimated that hypoxemia alone is an appropriate surrogate for ARDS,using Pa O2/FIO2(P/F)ratios drawn from clinical databases,with no correlation to radiographicﬁndings.8,18Y20 Given the multiple possible etiologies of posttraumatic hypoxemia and the deliberate speciﬁcity with which consensus deﬁnitionsO RIGINAL A RTICLESubmitted:October20,2014,Revised:December11,2014,Accepted:December 12,2014,Published online:March4,2015.From the Department of Surgery(B.M.H.,L.Z.K.,B.J.R.,A.S.C.,M.F.N.,R.A.C., M.J.C.),and Division of Pulmonary and Critical Care Medicine,Departments ofMedicine and Anesthesia(C.M.H., C.S.C.),University of California SanFrancisco and San Francisco General Hospital,San Francisco,California.This study was presented at the2014Thomas L.Petty Aspen Lung Conference,‘‘Rebuilding the Injured Lung,’’June4,2014,in Aspen,Colorado.Address for reprints:Benjamin M.Howard,MD,MPH,Department of Surgery, Ward3A,San Francisco General Hospital,1001Potrero Ave,Room3C-38,SanFrancisco,CA94110;email:benjamin.howard@.DOI:10.1097/TA.0000000000000583of ARDS have been developed,such a practice may lead to misleading conclusions based on expanded and imprecise in-clusion criteria.Whether hypoxemia is indeed a useful surrogate for ARDS remains an unanswered question in trauma epidemi-ology research.We sought to describe the differences in demographics, injury proﬁles,clinical characteristics,and outcomes between patients with hypoxemia alone and those with adjudicated ARDS;we also sought to delineate the differences between patients with hypoxemia and those who required intubation but never developed hypoxemia.We aimed to identify independent predictors of both hypoxemia and ARDS.We hypothesized that in a critically injured trauma cohort requiring intubation, nonhypoxemic,hypoxemic,and ARDS patients represent dis-tinct groups with unique characteristics and predictors.PATIENTS AND METHODSComprehensive demographic,injury,clinical,and out-comes data were prospectively collected on621critically injured highest-level trauma activation patients at an urban Level1 trauma center between2005and2013.These patients required intubation and mechanical ventilation and survived at least6 hours from the time of admission;data were collected out to28 days following admission.Data were collected under a protocol approved by the University of California,San Francisco Com-mittee on Human Research.Hypoxemia was deﬁned as a P/F ratio of300or lower during theﬁrst8days of admission,and ARDS was determined using the Berlin deﬁnition:acute-onset hypoxemia(P/F ratio e300)within1week of traumatic insult, in the presence of bilateral pulmonary opacities on chest radio-graph,not explained by effusions,lobar collapse,cardiac failure, orﬂuid overload.21Radiographs obtained for clinical indications were reviewed by two expert physicians blinded to clinical data and were assessed for the presence of bilateral pulmonary opacities;those deemed positive by consensus were designated as adjudicated ARDS patients.Patients in the cohort were managed with a lung-protective ventilation strategy according to the ARDSNet protocol,where clinically appropriate.22 Massive transfusion was deﬁned as10or greater units of packed red blood cells(pRBCs)transfused in24hours.To account for survivor bias,those patients who did not survive 24hours were counted as receiving massive transfusion if they were transfusedﬁve or greater units of pRBCs in12hours or2.5 or greater units of pRBCs in6hours,as described previously.23 Multiorgan failure was deﬁned using the Denver Postinjury Multiple Organ Failure Score,which grades degree of combined cardiac,pulmonary,renal,and hepatic dysfunction.24Data are presented as mean(SD),median(interquartile range),or percentage;univariate and group comparisons were made using Student’s t test or one-way analysis of variance for normally distributed data,Wilcoxon rank-sum or Kruskal-Wallis testing for skewed data,and Fisher’s exact test for proportions. An>G0.05was considered signiﬁcant.For group comparisons, differences between multiple groups were assessed if the overall across-group comparison test was signiﬁcant(>G0.05); Bonferroni correction was then made for multiple between-group comparisons(>G0.017for comparisons between three groups).The depicted N inﬁgures and tables represents the total number of patients in the respective group.Logistic regression was used to assess predictors of both hypoxemia and ARDS.To preclude confounding by timing of exposures and outcomes,we excluded from the models patients who developed hypoxemia or ARDS during theﬁrst24hours of admission;in this way,we could ascertain that predictors truly preceded their respective outcomes.Patients who died in theﬁrst24hours were also ex-cluded since they by deﬁnition could not develop the outcome in question.As a sensitivity analysis,additional models were subsequently constructed including patients who died or devel-oped hypoxemia or ARDS in theﬁrst24hours,using as predictors only variables that preceded hospital arrival(e.g.,demographics, injury proﬁle);these identiﬁed no substantive differences in pre-dictors from the main regression analysis presented here(data not shown).All analysis was performed by the authors using Stata version12(StataCorp,College Station,TX).RESULTSOf the621critically injured trauma patients requiring in-tubation,395(64%)developed hypoxemia in theﬁrst8days of admission,with P/F ratio of300or lower;the other226intubated patients(36%)never developed hypoxemia(Fig.1).Among the hypoxemic patients,183(46%,or30%of the total cohort)were diagnosed with ARDS based on blinded two-physician review, while212(54%,or34%of the total cohort)never developed radiographicﬁndings consistent with ARDS.The demographic,injury,clinical,and outcome data by group are depicted in Table1.Across the three respective groups (nonhypoxemic,hypoxemic with P/F ratio e300,adjudicated ARDS),there were no signiﬁcant differences in age or sex;de-mographics were consistent with those expected in an urban trauma population.Patients who did not develop hypoxemia or ARDS had a lower mean body mass index(BMI).ARDS patients had a higher rate of blunt mechanism of injury(83%)than nonhypoxemic or hypoxemic non-ARDS patients(72%).There were no signiﬁcant differences between groups with respect to underlying comorbidities,including chronic obstructive pul-monary disease,asthma,diabetes mellitus,or underlying cardiac disease(data not shown).In this intubated cohort,nonhypoxemic patients had higher median blood alcohol levels compared with the hyp-oxemic patients,who in turn had higher median blood alcohol compared with patients diagnosed with ARDS(203vs.152vs.67.5mg/dL,p=0.033across groups).Reported history of smoking increased from nonhypoxemic to hypoxemic to ARDS patients,although this did not reach statistical signiﬁ-cance(58%vs.69%vs.74%,p=0.062across groups).There were no signiﬁcant differences in the use of illicit drugs,either by toxicology screening data or by history(data not shown).Injury proﬁles differed between groups,with a step-wise increase in median Injury Severity Score(ISS)from nonhypoxemic to hypoxemic to ARDS patients(16vs.26vs.30, p G0.001across and between groups);rate of chest injury(29% vs.39%vs.58%,p G0.001across groups)and rate of severe chest injury(Abbreviated Injury Scale[AIS]score93,22%vs. 29%vs.58%,p G0.001across groups)demonstrated similar stepwise increases.Rate of rib fractures also increased across groups(15%vs.24%vs.41%,p G0.001across groups).J Trauma Acute Care SurgVolume78,Number4Howard et al.Median Glasgow Coma Scale (GCS)score decreased across the groups,from 9.5to 8to 7(p =0.041across groups),and rate of head injury (AIS score Q 1)increased from 60%to 74%to 83%(p G 0.001across groups).Corresponding physiologic parameters on admission also demonstrated stepwise trends in severity,with increasing mean heart rate across groups (93vs.98vs.107,p G 0.001across groups)as well as increasing mean base deﬁcit (j 3.3vs.j 5.4vs.Figure 1.Study population.TABLE 1.Demographics,Clinical Characteristics,and Outcomes by Hypoxemia/ARDS StatusP/F ratio 9300P/F ratio e 300,No ARDSARDS p n =226n =212n =183Age,y 37(27Y 54)39(25Y 57.5)39(27Y 54)0.660Male8075810.307BMI,mean (SD),kg/m 225.5(4.7)27.3(5.3)27.6(6.1)G 0.001Blunt mechanism 7272830.007Blood alcohol,mg/dL 203(0Y 321)152(0Y 245)68(0Y 284)0.033Smoking history 5869730.062ISS16(5Y 26)26(17Y 34)30(25Y 41)0.002*Chest Injury (any)293958G 0.001Severe chest injury (AIS score 93)222949G 0.001Rib fracture (any)152441G 0.001*GCS score9.5(5Y 14)8(4Y 14)7(3Y 13)0.041Head injury (any)607483G 0.001Admission heart rate,mean (SD)93.2(24.9)98.3(28.9)106.7(25.4)G 0.001Admission systolic blood pressure,mean (SD),mm Hg 127.9(32.3)128.8(35.7)127(35.2)0.879Admission base excess,mean (SD),mEq/L j 3.3(5.5)j 5.4(5.6)j 7.4(6.3)G 0.001*Prehospital crystalloid,mL100(0Y 250)150(50Y 300)100(0Y 300)0.047Intravenous crystalloid 0Y 6h,mL 2,085(915Y 3,180)3,000(1,500Y 4,500)3,590(2,075Y 6,095)G 0.001*Intravenous crystalloid 7Y 24h,mL 2,265(1,590Y 3,180)2,895(2,150Y 4,020)2,995(2,200Y 4,670)G 0.001Intravenous colloid 0Y 6h,mL 0(0Y 0)0(0Y 0)0(0Y 0)0.163Transfusion (any)at 24h 445975G 0.001*Massive transfusion61323G 0.001*Ventilator-free days (in 28d)26(25Y 27)19(0Y 25)2(0Y 16)G 0.001*Ventilator-associated pneumonia 0.4528G 0.001*Multiorgan failure 0.4943G 0.001*Total hospital days 5(2Y 12)10(3Y 25)21(9Y 44)G 0.001*Total ICU days 2(2Y 4)5(2Y 12)14(7Y 24)G 0.001*Mortality at 24h 41030.006Mortality at discharge142735G 0.001*Signiﬁcance between all groups following Bonferroni correction (>G 0.017).Data presented as percentage unless stated,mean (SD),or median (interquartile range).Statistical testing performed with analysis of variance or Student’s t ,Kruskal-Wallis,or Wilcoxon rank-sum,or Fisher’s exact tests.p values shown are for across-group statistical tests.J Trauma Acute Care Surg Volume 78,Number 4Howard et al.j7.4mEq/L,p G0.003across and between groups).There were no signiﬁcant differences in admission temperature or systolic blood pressure.With regard to resuscitation,there were no clinically signiﬁcant differences in the amount of prehospital crystalloid administered.However,there were signiﬁcant stepwise dif-ferences in the median amount of crystalloid received in the 6hours following presentation to the trauma center:non-hypoxemic patients received2,085mL of crystalloid versus 3,000mL for hypoxemic patients and3,590mL for patients who developed ARDS(p G0.001across and between groups). This trend was also observed during the following time in-terval,from7hours to24hours(2,265vs.2,895vs.2,995mL, p G0.001across groups).In parallel to the trend seen in crystalloid administration, the rates of blood product transfusion increased across the respective study groups.As shown in Table1,the percentage of nonhypoxemic patients receiving any blood product in theﬁrst 24hours was44%versus59%for patients who had hypoxemia and75%for patients diagnosed with ARDS(p G0.001across and between groups).A similar increase was seen with respect to massive transfusion,from6%in nonhypoxemic patients up to13%in those who developed hypoxemia and23%for ARDS patients(p G0.001across and between groups).Signiﬁcant increases were seen in the transfusion rates of all categories of blood products,including pRBCs,fresh frozen plasma(FFP), and platelets,as depicted in Figure2.The three groups demonstrated signiﬁcant differences in ventilation requirements and critical care outcomes.Non-hypoxemic patients had signiﬁcantly more ventilator-free days than hypoxemic or ARDS patients(26vs.19vs.2ventilator-free days,p G0.001across and between groups).Ventilator-associated pneumonia incidence was lowest in nonhypoxemic patients(0.4%)and increased in hypoxemic(5%)and ARDS patients(28%,p G0.001across and between groups);mul-tiorgan failure followed a similar pattern(0.4%vs.9%vs.43%, p G0.001across and between groups).ARDS patients had the longest hospital and intensive care unit(ICU)stays,while nonhypoxemic patients had the shortest stays(both p G0.001,across and between groups). Overall mortality was increased in the hypoxemia(27%)and ARDS(35%)groups,compared with nonhypoxemic patients (14%,p G0.001across groups).Logistic regression analyses were conducted to identify independent predictors of both hypoxemia and ARDS.To assess independent predictors of hypoxemia alone,ARDS patients were excluded from the hypoxemia models.In univariate logistic regression,BMI,head injury(by AIS head),early(0Y6hours) transfusion of any blood product,late(7Y24hours)transfusion of pRBCs,and late administration of crystalloid or colloid were found to be signiﬁcant predictors of hypoxemia(all p G0.05, Table2).When incorporating these factors into a multiple logistic regression model including chest injury(area under the curve,0.76with n of272and91patients who developed outcome),the signiﬁcant predictors of hypoxemia were BMI (per5kg/m2,odds ratio[OR],1.34;95%conﬁdence interval [CI],1.02Y1.79;p=0.037),head injury(OR,1.31;95%CI, 1.13Y1.53;p G0.001),chest injury(OR, 1.28;95%CI, 1.05Y1.54,p=0.012),early FFP transfusion(by unit,OR,1.39; 95%CI,1.11Y1.74;p=0.005),and late crystalloid adminis-tration(by500-mL aliquot;OR,1.14;95%CI,1.03Y1.25;p= 0.008)(Table2).In a similar fashion,logistic regression was conducted to analyze predictors of ARDS in the study population.In uni-variate logistic regression,blunt mechanism,head injury(by AIS score),chest injury(by AIS score),early(0Y6hours)or late(7Y24hours)administration of crystalloid,and early or late transfusion of all blood products were signiﬁcant predictors of ARDS(all p G0.05,Table3).When adjusting for these vari-ables in a multiple logistic regression model(area under the curve,0.80,with total model n of483,and105patients who developed ARDS outcome),the remaining signiﬁcant pre-dictors of ARDS were head injury(OR, 1.47;95%CI, 1.27Y1.71;p G0.001),chest injury(OR, 1.36;95%CI, 1.17Y1.58;p G0.001),early administration of crystalloid(by 500mL;OR,1.08;95%CI,1.02Y1.15;p=0.006),and late transfusion of platelets(by unit;OR, 5.55;95%CI, 2.37Y12.99;p G0.001)(Table3).DISCUSSIONSince its earliest description nearly half a century ago, ARDS has been a recognized and dire complication of severe trauma.The incidence and severity of ARDS,from causes both traumatic and nontraumatic,represent a major concern in both critical care and public health.25Recognizing that diverse trau-matic and nontraumatic insults lead to a similar pathophysio-logic process and end point,investigators have worked to arrive at consensus deﬁnitions of this acute lung injury,to facilitate broad epidemiologic characterizations,evaluate outcomes across populations,and assess potential therapeutic approaches.26 Although these consensus deﬁnitions have evolved with im-proved understanding of lung injury at both the population and molecular level,they have consistently included both the acuteFigure2.Transfusion requirements by group.J Trauma Acute Care Surg Volume78,Number4Howard et al.onset of hypoxemia and a corresponding radiographic ﬁnding indicative of pulmonary inﬁltration.21,27Because of limitations in available data sets that lack ra-diographic ﬁndings,several recent investigations in the trauma literature have resorted to using hypoxemia alone to determine pulmonary dysfunction from presumed ARDS;8,20others have deferred actual review of radiographs to use billing codes or secondary radiology reports.18,19Using such protocols is less resource intensive and allows investigators to analyze ﬁndings from large clinical databases.However,little is known as to the effects of conﬂating hypoxemia with rigorously adjudicated ARDS or what potentially erroneous conclusions might be drawn from such an approach.In this study,using the criterion standard of blinded two-physician review of chest radiographs to adjudicate ARDS in intubated trauma patients,we found signiﬁcant differences in clinical characteristics and outcomes between patients with no hypoxemia,those with hypoxemia but no ARDS,and those with conﬁrmed ARDS.Although basic demographics such as age,sex,and comorbidities were similar across these three groups,differences in severity of injury,degree of shock,ﬂuid resusci-tation and transfusion requirements,and overall mortalityfollowed a stepwise trend,increasing from the nonhypoxemic to the hypoxemic to the ARDS group.As such,these groups may be considered to be different in terms of degree,with more severely injured patients in the hypoxemic group and most severely in-jured patients in the ARDS group.We used logistic regression analysis to assess indepen-dent risk factors for both hypoxemia and ARDS,adjusting for injury severity and transfusion parameters.This analysis re-vealed that,in addition to the previously mentioned differences in degree,these groups were actually different in kind as well.In multiple logistic regression,the signiﬁcant risk factors for hypoxemia after 24hours included severity of head injury,severity of chest injury,BMI,amount of late (7Y 24hours)crystalloid administration,and amount of early (0Y 6hours)FFP transfusion.A similar analysis for ARDS after 24hours identiﬁed severity of both head and chest injury,amount of early crystalloid administration,and amount of late platelet transfusion as independent risk factors.Our ﬁnding of unique risk factors for both hypoxemia and ARDS underscores the clinical differences between these groups and corresponds to clinical intuition:patients may develop hypoxemia for a host of reasons,from mucus pluggingTABLE 2.Logistic Regression:Predictors of Hypoxemia (P/F Ratio e 300)After 24HoursUnivariateMultivariate OR95%CI p OR 95%CI p BMI (per 5kg/m 2) 1.32 1.03Y 1.690.027 1.34 1.02Y 1.790.037Head injury (AIS) 1.25 1.10Y 1.410.001 1.31 1.13Y 1.53G 0.001Chest injury (AIS) 1.130.97Y 1.330.122 1.28 1.05Y 1.540.012pRBCs 0Y 6h,U 1.08 1.03Y 1.140.0040.880.75Y 1.040.129FFP 0Y 6h (units) 1.17 1.07Y 1.27G 0.001 1.39 1.11Y 1.740.005Platelets 0Y 6h,U1.66 1.08Y2.550.0210.760.30Y 1.910.559Crystalloid 7Y 24h (500mL) 1.22 1.12Y 1.32G 0.001 1.14 1.03Y 1.250.008Colloid 7Y 24h (500mL) 4.09 1.24Y 13.440.020 3.150.85Y 11.680.086pRBCs 7Y 24h,U1.251.01Y 1.540.0391.010.77Y 1.310.994Bold variables are those that remain signiﬁcant predictors in multivariate analysis.Patients were excluded if hypoxemia was diagnosed during ﬁrst 24hours of admission,if diagnosed with ARDS (to assess predictors of hypoxemia alone),or if patient died before 24hours.Total N for this model 272,with 91developing outcome of interest (hypoxemia).TABLE 3.Logistic Regression:Predictors of ARDS After 24HoursUnivariateMultivariateOR95%CI p OR 95%CI p Blunt mechanism 2.05 1.17Y 3.590.013 1.760.82Y 3.740.145Head injury (AIS) 1.44 1.27Y 1.63G 0.001 1.47 1.27Y 1.71G 0.001Chest injury (AIS)1.33 1.17Y 1.51G 0.001 1.36 1.17Y 1.58G 0.001Crystalloid 0Y 6h (by 500mL) 1.07 1.03Y 1.110.001 1.08 1.02Y 1.150.006pRBCs 0Y 6h,U 1.05 1.01Y 1.090.0100.940.83Y 1.060.297FFP 0Y 6h,U 1.08 1.03Y 1.140.001 1.030.89Y 1.180.729Platelets 0Y 6h,U1.41 1.07Y 1.870.016 1.460.94Y2.270.091Crystalloid 7Y 24h (by 500mL) 1.11 1.05Y 1.17G 0.001 1.050.98Y 1.120.203pRBCs 7Y 24h,U 1.34 1.17Y 1.55G 0.0010.990.76Y 1.280.924FFP 7Y 24h,U 1.36 1.14Y 1.61G 0.0010.930.67Y 1.270.640Platelets 7Y 24h,U5.532.82Y 10.85G 0.0015.552.37Y 12.99G 0.001Bold variables are those that remain signiﬁcant predictors in multivariate analysis.Patients were excluded if ARDS was diagnosed in the ﬁrst 24hours of admission or if patient died before 24hours.Total N for this model 483,with 105developing outcome of interest (ARDS).J Trauma Acute Care Surg Volume 78,Number 4Howard et al.to shunting to atelectasis,whereas ARDS likely represents a speciﬁc severe biologic syndrome.One shared risk factor for both hypoxemia and ARDS,degree of head injury,likewise makes clinical sense and resonates with the previous literature linking traumatic brain injury to acute lung injury;28,29the exact mechanisms of this correlation in ARDS are not well characterized and may reﬂect both systemic inﬂammation and the use of traumatic brain injury Y speciﬁc ventilator manage-ment strategies.30The correlation of chest injury and hypox-emia also corresponds to clinical experience,while theﬁnding of chest trauma severity as an independent predictor of ARDS supports direct lung injury(including pulmonary contusion)as a predisposing factor for acute lung injury,corroborating the trauma literature to date.17,31Y33That BMI predicts hypoxemia resonates clinically as well,in that injured patients with larger habitus may have higher risk of atelectasis,along with pul-monary mechanics that impair adequate oxygenation.The hydrostatic and proinﬂammatory effects of intravenous crystalloid on the lung have been described for decades,34Y36and a ﬂuid-restrictive strategy has been shown in a multicenter ran-domized clinical trial to improve clinical outcomes in ARDS;37 as such,ourﬁnding that early crystalloid administration inde-pendently predicts ARDS is not surprising.While the data provide no obvious mechanistic explanation for delayed crys-talloid as a risk factor for hypoxemia,it may well represent a surrogate of ongoing aggressive resuscitation(justiﬁed or not),which may in turn correlate to incidence of hypoxemia after24hours.Delayed platelet administration(7Y24hours after pre-sentation)was the strongest independent predictor of ARDS after 24hours in our cohort.This resonates with early theories on ARDS pathophysiology and platelet-related pulmonary dam-age38as well as with more recent clinical investigations8,39and animal model data implicating platelet sequestration as a key precipitating factor in neutrophil-mediated lung injury.40The exact mechanism of this relationship cannot be determined from our clinical data and could reﬂect either a direct insult from ongoing platelet transfusion or a secondary effect of early pul-monary platelet sequestration,prompting delayed platelet transfusion by clinicians in response to a low peripheral platelet count.Similarly,the association between early FFP administra-tion and hypoxemia after24hours may represent either a true biologic effect,as alluded to in previous studies,41or may be a surrogate for injury severity and resuscitation requirements in our population.This study has notable strengths:it draws on prospectively collected data from a relatively large set of intubated critically injured patients,uses blinded physician review of radiographs to conﬁrm ARDS diagnosis,and by careful patient selection en-ables identiﬁcation of clinical predictors that clearly precede the outcomes in question.It is of course limited in that it is a single-center study,although ourﬁndings should be applicable and relevant to other major urban trauma centers and similar patient populations.Moreover,as noted,despite the prospective col-lection of data in this trauma cohort,the granular details of minute-by-minute timing of potential exposures in theﬁrst hours of resuscitation could not be determined with certainty in this analysis;thus,we limited our regression analyses to assessing predictors of hypoxemia and ARDS after24hours.We acknowledge that the independent predictors of ARDS in theﬁrst24hours after injury may differ from those reported here,especially given the potential phenotypic heterogeneity of ARDS in trauma patients by time of onset.42Y44Of note, performing our regression analyses including all patients and excluding process-of-care variables to prevent confounding of exposure-outcome timing,we found no major differences from the predictors reported here.In sum,we have demonstrated that in a cohort of intubated trauma patients at a high-volume urban trauma center in the United States,hypoxemia and ARDS exist on a spectrum of injury severity proﬁle and resuscitation requirements,yet pa-tients with adjudicated ARDS represent a distinct group from those with hypoxemia alone.While ARDS is a well-described pathophysiologic syndrome,hypoxemia may result from vari-ous stimuli and may not be a meaningful indicator in the absence of acute lung injury.Hypoxemia does not seem to be an ap-propriate surrogate for lung injury,and future epidemiologic studies should thus incorporate precise,adjudicated ascertain-ment of ARDS.AUTHORSHIPB.M.H.,L.Z.K.,C.M.H.,R.A.C.,C.S.C.,and M.J.C.contributed to the study design,data collection,data analysis,data interpretation,writing, and critical revision.B.J.R.,A.S.C.,and M.F.N.contributed to the study design,data collection,and critical revision. ACKNOWLEDGMENTWe appreciate the participation of the ICU nursing staff and of the pa-tients and their families.DISCLOSUREThis study was supported by HL110969(to C.S.C.)and DoD W911NF-10-1-0384(to M.J.C.).REFERENCES1.Norton R,Kobusingye O.Injuries.N Engl J Med.2013;368(18):1723Y1730.2.Trunkey DD.Trauma.Accidental and intentional injuries account for moreyears of life lost in the U.S.than cancer and heart disease.Among the prescribed remedies are improved preventive efforts,speedier surgery and further research.Sci Am.1983;249(2):28Y35.3.Demetriades D,Kimbrell B,Salim A,Velmahos G,Rhee P,Preston C,Gruzinski G,Chan L.Trauma deaths in a mature urban trauma system: is‘‘trimodal’’distribution a valid concept?J Am Coll Surg.2005;201(3): 343Y348.4.Ciesla DJ,Moore EE,Johnson JL,Burch JM,Cothren CC,Sauaia A.Therole of the lung in postinjury multiple organ failure.Surgery.2005;138(4):749Y757.5.Ciesla DJ,Moore EE,Johnson JL,Cothren CC,Banerjee A,Burch JM,Sauaia A.Decreased progression of postinjury lung dysfunction to the acute respiratory distress syndrome and multiple organ failure.Surgery.2006;140(4):640Y647.6.Martin M,Salim A,Murray J,Demetriades D,Belzberg H,Rhee P.Thedecreasing incidence and mortality of acute respiratory distress syndrome after injury:a5-year observational study.J Trauma.2005;59(5):1107Y1113.7.Plurad D,Martin M,Green D,Salim A,Inaba K,Belzberg H,DemetriadesD,Rhee P.The decreasing incidence of late posttraumatic acute respiratory distress syndrome:the potential role of lung protective ventilation and conservative transfusion practice.J Trauma.2007;63(1):1Y7.8.Robinson BR,Cotton BA,Pritts TA,Branson R,Holcomb JB,Muskat P,Fox EE,Wade CE,del Junco DJ,Bulger EM,et al.Application of theJ Trauma Acute Care SurgVolume78,Number4Howard et al.。

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a r X i v :h e p -p h /9703321v 3 9 J u n 1997ICRR-Report-384-97-7KUNS-1437HE(TH)97/04hep-ph/9703321Infra-Red Fixed Pointsin an Asymptotically Non-Free TheoryMasako Bando∗Aichi University,Miyoshi,Aichi 470-02,JapanJoe Sato†Institute for Cosmic Ray ResearchThe University of Tokyo,Midori-Cho,Tanashi,Tokyo 188,JapanKoichi Yoshioka‡Department of Physics,Kyoto UniversityKyoto 606-01,JapanAbstractWe investigate the infrared ﬁxed point structure in asymptotically free and asymptotically non-free theory.We ﬁnd that the ratios of couplings converge strongly to their infrared ﬁxed points in the asymptotically non-free theory.1IntroductionThe manner in which the Yukawa couplings reproduce the masses of quarks and leptons is one of the unsolved problems in particle physics.These masses may be constrained by requiring some symmetry or by imposing grand uniﬁed theory and/or they may be related to gauge couplings.The latter is strongly indicated by the top quark mass.About3years ago,Lanzagorta and Ross[1]attempted to determine the relation between Yukawa couplings and gauge couplings through the infraredﬁxed point structure.This method in which the infraredﬁxed points may determine the heavy fermion masses wasﬁrst proposed by Pendleton and Ross[2].However,such an infraredﬁxed point has rarely been reached in usual asymptotically free(AF) standard models because of the infrared divergent character[3].Furthermore,since the coupling constants become very large in the low energy region,the perturbative treatment is no more guaranteed in the infrared region.More than40years ago,Landau proposed an attractive idea that low energy physics may be determined with an asymptotically non-free(ANF)theory.He illustrated this idea by showing the possibility to obtain a very smallﬁne structure constant.This idea was applied to determine the ratio of gauge couplings[4].In particular,it was pointed out by Moroi et al.[5]that the minimal supersymmetric standard model(MSSM)with1extra vector-like family(EVF)gives the observed ratio of the gauge couplings(Weinberg angle).In a previous paper[6],we investigated a possible scenario of the standard gauge symmetry with ANF character and showed that due to the ANF gauge couplings the top Yukawa coupling is quite insensitive to their initial valuesﬁxed at GUT scale M G.We would like to stress that such strong convergence of Yukawa couplings to their infraredﬁxed points is a common feature appearing in ANF theories.In this paper we investigate how strongly the couplings are focused into their in-frared points in ANF theories and demonstrate the structure of the renormalization-groupﬂow.As illustrations we take the supersymmetric standard models with AF and ANF gauge couplings and compare them by concentrating on their infrared structure.2Infrared Structure of AF and ANF Theories Before studying realistic(AF and ANF)models weﬁrst consider a simple gauged Yukawa system which has one gauge coupling g and one Yukawa coupling y,whose 1-loopβ-functions aredαα2,(2.1)2πdαy2πaαy −c α,(2.2)whereα≡g 24π,t =lnµdt=aα(2.4)R ∗=c −bR (t )=α(t )R (M G ),(2.6)B ≡1−cα(M G )Bprovides the criterion on rate at which R approaches the infrared ﬁxedpoint value R ∗.Note that this factor is independent of the detailed information of the system and is determined from gauge coupling alone.The b -dependence of the suppression factor ξis shown in Fig.1,from which we ﬁnd a large diﬀerence between AF (b >0)and ANF (b <0)cases.In the AF case the point b =c at which B becomes 0corresponds to ξ=1.If we dare to extrapolate our formula above this critical point,ξbecomes larger than 1,but R ∗becomes negative and is no more an infrared ﬁxed point.From (2.6)we see that ξblows up and R (t )tends to zero in the low energy limit [7].On the other hand,in the ANF case there is always a nontrivial infrared ﬁxed point R ∗(>0),and convergence to R ∗becomes much better.Now we illustrate the diﬀerence in behavior of the AF and ANF theories by applying this formula to two models,the minimal supersymmetric standard model and the MSSM with one extra vector-like family (EVF)[4,5,6].Typical behavior of the running gauge couplings is shown in Fig.2.They are uniﬁed at the same scale in the two cases,but with diﬀerent uniﬁed couplings.Let us ﬁrst exhibit typical values for the AF and ANF cases,taking α=α3,αy =αt with a realistic value of α3(see §3for details),-4-202460.511.5ξ=α3(1TeV)3)468101214161020304050α−1log 10(µ/[GeV])Figure 2:Typical µ-dependence of α1(µ),α2(µ),α3(µ)in the MSSM (dashed lines)and the MSSM +1EVF (solid lines).MSSM :b =3,c =169α3(M Z )0.04−7/9∼0.43,(2.8)MSSM +1EVF :b =−1,c =163α3(M Z )1.019/3∼10−6.(2.9)The suppression factors can be read oﬀFig.1(indicated by arrows).We can see the situation more clearly by comparing the µ-dependence of αt /α3in the AF and ANF cases.In the MSSM +1EVF,the convergence to the infrared ﬁxed point is much better than that in the MSSM,and its ﬁxed point value depends very weakly on the initial value at M G (Fig.4).This is because gauge couplings are asymptotically non-free and their uniﬁed coupling is very large at M G (Fig.2).Next we investigate the RG ﬂow in the (α3,αt )plane.The RG ﬂow behavesquite diﬀerently according to the regions separated by the ﬁxed line αt /α3=R ∗t (Figs.5and 6).In the lower region of the AF case,the Yukawa coupling,as well as the gauge468101214160.20.40.60.81log 10(µ/[GeV])R tαt (M G )=0.04αt (M G )=0.03αt (M G )=0.02αt (M G )=0.01αt (M G )=0.004Figure 3:R t in the MSSM (M G =1.6×1016GeV ,αGUT =0.04)468101214160.20.40.60.81R tαt (M G )=1.0αt (M G )=0.5αt (M G )=0.1αt (M G )=0.01αt (M G )=0.001Figure 4:R t in the MSSM +1EVF (M G =7.0×1016GeV ,αGUT =1.0)0.20.40.60.810.20.40.60.81α3αtﬁxed lineFigure 5:RG ﬂow diagram in the MSSM(The arrows denote the ﬂow directions toward the infrared region.)0.20.40.60.810.20.40.60.81α3αtﬁxed lineFigure 6:RG ﬂow diagram in the MSSM +1EVF(The arrows denote the ﬂow directions toward the infrared region.)coupling,is found to be asymptotically free,and we have a nontrivial continuum limit [7].Although the ratioﬁnally approaches the infraredﬁxed point,in the infrared region both of the couplings become very large,and the one-loop approximation is no longer reliable.For the other situations,either or both couplings are divergent at high energy. In the lower region of the ANF case the gauge coupling governs the Yukawa coupling very strongly.The gauge coupling diverges at some high energy scale.In the upper region for both cases,on the other handαt diverges at some high energy scale. Then the theory becomes trivial in the continuum limit and we should make use of cut-oﬀtheory.The former corresponds to dynamical gauge boson[8]and the latter, dynamical Higgs boson[9].It is noted that the ANF case is in strong contrast with the AF case.In both the upper and lower regions,the ratio evidently has an infraredﬁxed point where the one loop approximation becomes more and more valid.This can be clearly seen in Fig.6.This infrared stability is very attractive and may make the determination of Yukawa coupling constants feasible.3Infrared Solutions of MSSM+1EVFKeeping the above attractive features in mind,we further undertake an analysis of the infraredﬁxed point solutions of MSSM+1EVF,which includes three gauge and Yukawa couplings.We suppose that the superpotential takes the formW=W3+W4+W¯4,(3.1)W3=y t3Q3H¯t3+y b3Q3¯H¯b3+yτ3L3¯H¯τ3,(3.2)W4=y t4Q4H¯t4+y b4Q4¯H¯b4+yτ4L4¯H¯τ4,(3.3)W¯4=y¯t¯Q¯Ht¯4+y¯b¯QHb¯4+y¯τ¯LHτ¯4,(3.4) and the Yukawa couplings satisfy∗y t3=y t4≡y t,y b3=y b4≡y b,yτ3=yτ4≡yτ,(3.5) y¯t=y¯b=y¯τ=0.(3.6)With these assumptions,there exist parameter regions where both the low-energy experimental values and the high energy GUT-like boundary conditions are consis-tently described[6].Then the1-loopβ-functions for the ratio of the couplings to α3(R i≡αi/α3)aredR 12πα3R 1(10.6R 1−1),(3.7)dR 22πα3R 2(5R 2−1),(3.8)dR t2πα3R t9R t +R b −133,(3.9)dR b2πα3R b R t +9R b +2R τ−73,(3.10)dR τ2πα3R τ6R b +5R τ−9†Strictly speaking,R 1and R 2do not converge to their ﬁxed pointvalues.However,the diﬀer-ences R i (1TeV)−R ∗i (i =1,2)are small enough for us to use the result (3.13).R ∗1=0.0943,R ∗2=0.2,(3.12)R ∗t =0.702,R ∗b =0.697.(R τ∼0.0)(3.13)From Figs.4and 8,we ﬁnd that these quantities indeed reach their ﬁxed points.As we mentioned before,these values are aﬀected little by the initial values at M G because of the asymptotically non-free gauge couplings.We are conﬁdent that the infrared ﬁxed points obtained from these solutions are physically signiﬁcant and provide us with reliable low-energy parameters.468101214160.20.40.60.81R bαb (M G )=1.0αb (M G )=0.5αb (M G )=0.1αb (M G )=0.01αb (M G )=0.001Figure 8:R b in the MSSM +1EVF (M G =7.0×1016GeV ,αGUT =1.0)In the case at hand,by using these ﬁxed point solutions and the experimental value of α3(1TeV)∼0.093,we obtain,for example,‡m t (M Z )∼178GeV ,m b (M Z )∼3.2GeV .(3.14)(tan β∼58)These values are certainly consistent with the experimental values [10]m t (M Z )∼180±10GeV ,m b (M Z )∼3.1±0.4GeV .(3.15)4ConclusionWe found interesting infrared structure which is commonly seen in ANF theories. This is an important diﬀerence between AF and ANF theories.This possibility has long been observed but has never been taken serious.The existence of extra fermions has been discussed from various points of view: in deriving CP violation,dynamical SUSY breaking,hierarchical mass matrix,and so on.In particular,GUT models beyond standard models,including string models and supergravity models,predict additional fermions quite naturally.We can expect that at low energy,the theory is asymptotically non-free.We would like to stress that since ANF theories have strong predictive powers because of the strong convergence of couplings(ratio of couplings)to infraredﬁxed points,their study is considered important.AcknowledgmentsThe authors would like to express their sincere thanks to T.Kugo and T.Yanagida for their valuable comments and encouragement.The previous work with T.Takeuchi and T.Onogi(as well as J.S.and M.B.)has provided a strong motivation for this work,and discussions with them were instructive.A part of this work was performed during the Kashikojima Workshop held in August1996at Kashikojima Center, which was supported by a Grand-in Aid for Scientiﬁc Research(No.07304029) from the Ministry of Education,Science and Culture.M.B.is supported in part by the Grand-in Aid for Scientiﬁc Research(No.33901-06640416)from the Ministry of Education,Science and Culture.References[1]nzagorta and G.G.Ross,Phys.Lett.349B(1995)319[2]B.Pendleton and G.G.Ross,Phys.Lett.98B(1981)291[3]C.T.Hill,Phys.Rev.D24(1981)691[4]L.Maiani,G.Parisi and R.Petronzio,Nucl.Phys.B136(1978)115[5]T.Moroi,H.Murayama and T.Yanagida,Phys.Rev.D48(1993)2995[6]M.Bando,J.Sato,T.Onogi and T.Takeuchi,hep-ph/9612493[7]M.Harada,Y.Kikukawa,T.Kugo and H.Nakano,Prog.Theor.Phys.92(1994)1161[8]T.Saito and K.Shigemoto,Prog.Theor.Phys.57(1977)242H.Terazawa,K.Akama and Y.Chikashige,Phys.Rev.D15(1977)480M.Bando,Y.Taniguchi and S.Tanimura,hep-th/9610244[9]V.A.Miranskii,M.Tanabashi and K.Yamawaki,Phys.Lett.221B(1989)177W.A.Bardeen,C.T.Hill and M.Lindner,Phys.Rev.D41(1989)1647M.Bando,T.Kugo,N.Maekawa,N.Sasakura,Y.Watabiki and K.Suehiro, Phys.Lett.246B(1990)466M.Bando,T.Kugo,N.Maekawa and H.Nakano,Phys.Rev.D44(1991)2957 [10]Particle Data Group,Phys.Rev.D54(1996)1。