On an Estimate of the Bhattacharyya Distance_

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tpo32三篇托福阅读TOEFL原文译文题目答案译文背景知识

tpo32三篇托福阅读TOEFL原文译文题目答案译文背景知识阅读-1 (2)原文 (2)译文 (5)题目 (7)答案 (16)背景知识 (16)阅读-2 (25)原文 (25)译文 (28)题目 (31)答案 (40)背景知识 (41)阅读-3 (49)原文 (49)译文 (53)题目 (55)答案 (63)背景知识 (64)阅读-1原文Plant Colonization①Colonization is one way in which plants can change the ecology of a site.Colonization is a process with two components:invasion and survival.The rate at which a site is colonized by plants depends on both the rate at which individual organisms(seeds,spores,immature or mature individuals)arrive at the site and their success at becoming established and surviving.Success in colonization depends to a great extent on there being a site available for colonization–a safe site where disturbance by fire or by cutting down of trees has either removed competing species or reduced levels of competition and other negative interactions to a level at which the invading species can become established.For a given rate of invasion,colonization of a moist,fertile site is likely to be much more rapid than that of a dry, infertile site because of poor survival on the latter.A fertile,plowed field is rapidly invaded by a large variety of weeds,whereas a neighboring construction site from which the soil has been compacted or removed to expose a coarse,infertile parent material may remain virtually free of vegetation for many months or even years despite receiving the same input of seeds as the plowed field.②Both the rate of invasion and the rate of extinction vary greatly among different plant species.Pioneer species-those that occur only in the earliest stages of colonization-tend to have high rates of invasion because they produce very large numbers of reproductive propagules(seeds,spores,and so on)and because they have an efficient means of dispersal(normally,wind).③If colonizers produce short-lived reproductive propagules,they must produce very large numbers unless they have an efficient means of dispersal to suitable new habitats.Many plants depend on wind for dispersal and produce abundant quantities of small,relatively short-lived seeds to compensate for the fact that wind is not always a reliable means If reaching the appropriate type of habitat.Alternative strategies have evolved in some plants,such as those that produce fewer but larger seeds that are dispersed to suitable sites by birds or small mammals or those that produce long-lived seeds.Many forest plants seem to exhibit the latter adaptation,and viable seeds of pioneer species can be found in large numbers on some forest floors. For example,as many as1,125viable seeds per square meter were found in a100-year-old Douglas fir/western hemlock forest in coastal British Columbia.Nearly all the seeds that had germinated from this seed bank were from pioneer species.The rapid colonization of such sites after disturbance is undoubtedly in part a reflection of the largeseed band on the forest floor.④An adaptation that is well developed in colonizing species is a high degree of variation in germination(the beginning of a seed’s growth). Seeds of a given species exhibit a wide range of germination dates, increasing the probability that at least some of the seeds will germinate during a period of favorable environmental conditions.This is particularly important for species that colonize an environment where there is no existing vegetation to ameliorate climatic extremes and in which there may be great climatic diversity.⑤Species succession in plant communities,i.e.,the temporal sequence of appearance and disappearance of species is dependent on events occurring at different stages in the life history of a species. Variation in rates of invasion and growth plays an important role in determining patterns of succession,especially secondary succession. The species that are first to colonize a site are those that produce abundant seed that is distributed successfully to new sites.Such species generally grow rapidly and quickly dominate new sites, excluding other species with lower invasion and growth rates.The first community that occupies a disturbed area therefore may be composed of specie with the highest rate of invasion,whereas the community of the subsequent stage may consist of plants with similar survival ratesbut lower invasion rates.译文植物定居①定居是植物改变一个地点生态环境的一种方式。

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Robust Fragments-based Tracking using the Integral HistogramAmit Adam and Ehud RivlinDept.of Computer Science Technion-Israel Institute of TechnologyHaifa32000,Israel{amita,ehudr}@cs.technion.ac.ilIlan ShimshoniDept.of Management Information SystemsHaifa UniversityHaifa31905,Israel{ishimshoni}@mis.haifa.ac.ilAbstractWe present a novel algorithm(which we call“Frag-Track”)for tracking an object in a video sequence.The template object is represented by multiple image fragments or patches.The patches are arbitrary and are not based on an object model(in contrast with traditional use of model-based parts e.g.limbs and torso in human tracking).Every patch votes on the possible positions and scales of the ob-ject in the current frame,by comparing its histogram with the corresponding image patch histogram.We then mini-mize a robust statistic in order to combine the vote maps of the multiple patches.A key tool enabling the application of our algorithm to tracking is the integral histogram data structure[18].Its use allows to extract histograms of multiple rectangular re-gions in the image in a very efﬁcient manner.Our algorithm overcomes several difﬁculties which can-not be handled by traditional histogram-based algorithms [8,6].First,by robustly combining multiple patch votes,we are able to handle partial occlusions or pose change.Sec-ond,the geometric relations between the template patches allow us to take into account the spatial distribution of the pixel intensities-information which is lost in traditional histogram-based algorithms.Third,as noted by[18],track-ing large targets has the same computational cost as track-ing small targets.We present extensive experimental results on challenging sequences,which demonstrate the robust tracking achieved by our algorithm(even with the use of only gray-scale(non-color)information).1.IntroductionTracking is an important subject in computer vision with a wide range of applications-some of which are surveil-lance,activity analysis,classiﬁcation and recognition from motion and human-computer interfaces.The three main categories into which most algorithms fall are feature-based tracking(e.g.[3]),contour-based tracking(e.g.[15])and region-based tracking(e.g[13]).In the region-based cate-gory,modeling of the region’s content by a histogram or by other non-parametric descriptions(e.g.kernel-density esti-mate)have become very popular in recent years.In particu-lar,one of the most inﬂuential approaches is the mean-shift approach[8,6].With the experience gained by using histograms and the mean shift approach,some difﬁculties have been studied in recent years.One issue is the local basin of convergence that the mean shift algorithm has.Recently in[22]the au-thors describe a method for converging to the optimum from far-away starting points.A second issue,inherent in the use of histograms,is the loss of spatial information.This issue has been addressed by several works.In[26]the authors introduce a new sim-ilarity measure between the template and image regions, which replaces the original Bhattacharyya metric.This measure takes into account both the intensities and their position in the window.The measure is further computed efﬁciently by using the Fast Gauss Transform.In[12],the spatial information is taken into account by using“oriented kernels”-this approach is additionally shown to be useful for wide baseline matching.Recently,[4]has addressed this issue by adding the spatial mean and covariance of the pixel positions who contribute to a given bin in the histogram-naming this approach as“spatiograms”.A third issue which is not speciﬁcally addressed by these previous approaches is occlusions.The template model is global in nature and hence cannot handle well partial occlu-sions.In this work we address the latter two issues(spatial in-formation and occlusion)by using parts or fragments to rep-resent the template.Theﬁrst issue is addressed by efﬁcient exhaustive search which will be discussed later on.Given a template to be tracked,we represent it by multiple his-tograms of multiple rectangular sub regions(patches)of the template.By measuring histogram similarity with patchesof the target frame,we obtain a vote-map describing the possible positions of each patch in the target frame.We then combine the vote-maps in a robust manner.Spatial in-formation is not lost due to the use of spatial relationships between patches.Occlusions result in some of the patches contributing outlier vote-maps.Due to our robust method for combining the vote maps,the combined estimate of the target’s position is still accurate.The use of parts or components is a well known tech-nique in the object recognition literature(see chapter23in [11]).Examples of works which use the spatial relation-ships between detections of object parts are[21,17,16,2]. In[24]the issue of choosing informative parts which con-tain the most information concerning the presence of an ob-ject class is discussed.A novel application of detecting un-usual events and salient features based on video and image patches has recently been described in[5].In tracking,the use of parts has usually been in the con-text of human body tracking where the parts are based on a model of the human body-see[23]for example.Re-cently,Hager,Dewan and Stewart[14](followed by Fan et al.[10])analyzed the use of multiple kernels for tracking. In these works the connection between the intensity struc-ture of the target,the possible transformations it can expe-rience between consecutive frames,and the kernel structure used for kernel tracking was analyzed.This analysis gives insight on the limitations of single-kernel tracking,and on the advantages of multiple-kernel tracking.The parts-based tracking algorithm described in this work differs from these and other previous works in a number of important issues:•Our algorithm is robust to partial occlusions-the works in[14,10]cannot handle occlusions due to the non-robust nature of the objective function.•Our algorithm allows the use of any metric for com-paring two histograms,and not just analytically-tractable ones such as the Bhattacharyya or the equiv-alent Matusita metrics.Speciﬁcally,by using non-componentwise metrics the effects of bin-quantization are reduced(see section2.1and Fig.3).•The spatial constraints are handled automatically in our algorithm by the voting mechanism.In contrast, in[10]these constraints have to be coded in(e.g.the ﬁxed length constraint).•The robust nature of our algorithm and the efﬁcient use of the integral histogram allows one to use the algo-rithm without giving too much thought on the choice of multiple patches/kernels.In contrast,in[14,10]the authors carefully chose a small number of multiple ker-nels for each speciﬁc sequence.•We present extensive experimental validation,on out-of-the-lab real sequences.We demonstrate good track-ing performance on these challenging scenarios,ob-tained with the use of only gray-scale information.Our algorithm requires the extraction of intensity or color histograms over a large number of sub-windows in the target image and in the object template.Recently Pork-ili[18]extended the integral image[25]data structure to an“integral histogram”data structure.Our algorithm ex-ploits this observation-a necessary step in order to be able to apply the algorithm for real time tracking tasks.We ex-tend the tracking application described in[18]by our use of parts,which is crucial in order to achieve robustness to occlusions.2.Patch TrackingGiven an object O and the current frame I,we wish to locate O in the ually O is represented by a tem-plate image T,and we wish toﬁnd the position and the scale of a region in I which is closest to the template T in some sense.Since we are dealing with tracking,we assume that we have a previous estimate of the position and scale,and we will search in the neighborhood of this estimate.For clarity,we will consider in the following only the search in position(x,y).Let(x0,y0)be the object position estimate from the pre-vious frame,and let r be our search radius.Let P T= (dx,dy,h,w)be a rectangular patch in the template,whose center is displaced(dx,dy)from the template center,and whose half width and height are w and h respectively.Let (x,y)be a hypothesis on the object’s position in the cur-rent frame.Then the patch P T deﬁnes a corresponding rectangular patch in the image P I;(x,y)whose center is at (x+dx,y+dy)and whose half width and height are w and h.Figure1describes this correspondence.Given the patch P T and the corresponding image patch P I;(x,y),the similarity between the patches is an indication of the validity of the hypothesis that the object is indeed located at(x,y).If d(Q,P)is some measure of similaritybetween patch Q and patch P,then we deﬁneV PT(x,y)=d(P I;(x,y),P T)(1) When(x,y)runs on the range of hypotheses,we getV PT (·,·)which is the vote map corresponding to the tem-plate patch P T.2.1.Patch Similarity MeasuresWe measure similarity between patches by comparing their gray-level or color histograms.This allows moreﬂexi-bility than the standard normalized correlation or SSD mea-sures.Although for a single patch we lose spatial informa-tion by considering only the histogram,our use of multiple patches and their spatial arrangement in the template com-pensates for this loss.There are a number of known methods for comparing the similarity of two histograms[9].The simplest methods compare the histograms by comparing corresponding bins. For example,one may use the chi-square statistic or sim-ply the norm of the difference between the two histograms when considered as two vectors.The Kolmogorov-Smirnov statistic compares histograms by building the cumulative distribution function(that is cu-mulative sum)of each histogram,and comparing these two functions.The advantage over bin-wise methods is smooth-ing of nearby bin differences due to the quantization of mea-surements into bins.A more appealing approach is the Earth Mover’s Dis-tance(EMD)between two histograms,described in[20]. In this approach the actual dissimilarity between the bins themselves is also taken into account.The idea is to com-pute how much probability has to move between the various bins in order to transform theﬁrst histogram into the second. In doing so,bin dissimilarity is used:for example,in gray scale it costs more to move0.1probability from the[16,32) bin to the[128,144)bin,than to move it to the[32,47) bin.In theﬁrst case,the movement of probability is re-quired because of a true difference in the distributions,and in the second case it might be due simply to quantization errors.This is exactly the transportation problem of linear programming.In this problem the bases are always triangu-lar and therefore the problem may be solved efﬁciently.See [20]for more details and advantages of this approach.We have experimented with two similarity measures. Theﬁrst is the naive measure which treats the histograms as vectors and just computes the norm of their difference. The second is the EMD measure.For gray scale images, we used16bins.The EMD calculation is very fast and poses no problem.For color images,the number of bins is much larger(with only8bins per channel we get512bins). Therefore when using the EMD we took the K=10bins which obtained maximal counts,normalized them tounityPatch vote map − naive (dis)similarity Patch vote map − EMD (dis)similarity(a)(b)Figure3.V ote maps for the example patch using the the naive mea-sure and the EMD measure.The lower(darker)the vote-the more likely the position.Left(a)-naive measure.Right(b)-EMD.The EMD surface has a less blurred minimum,and is smoother at the same time.and then used the EMD.We used the original EMD code developed by Rubner[19].Figure2shows an example patch(we use gray scale in this example).We computed the patch vote map for all the locations around the patch center which are up to30pixels above or below and up to20pixels to the left or right.Fig-ure3shows the resulting vote maps when using the naive measure and the EMD measure.Note that in both measures the lower the value(darker in the image),the more simi-lar the histograms.The EMD surface is smoother and has a more distinct minimum than the surface obtained when using the naive measure.bining Vote MapsIn the last section we saw how to obtain a vote map V PT(·,·)for every template patch P T.The vote map gives a scalar score for every possible position(x,y)of the tar-get in the current frame I,given the information from patch P T.We now want to combine the vote maps obtained from all template patches.Basically we could sum the vote maps and look for the position which obtained the minimal sum(recall that our vote maps actually measure dissimilarity between patches). The drawback of this approach is that an occlusion affecting even a single patch may contribute a high value to the sum at the correct position,resulting in a wrong estimate.In other words,we would like to use a robust estimator which couldhandle outliers resulting from occluded patches or other rea-sons(e.g.partial pose change-for example a person turns his head).One way to make the sum robust to outliers is to bound the possible contribution of an outlierC(x,y)=PV P(x,y)V P(x,y)<TT V P(x,y)>=T(2)by some threshold T.If we adopt a probabilistic view ofthe measurement process-by transforming the vote mapto a likelihood map(e.g.by setting L P(x,y)=K∗exp−α∗V P(x,y))-then this method is equivalent to addinga uniform outlier density to the true(inlier)density.Min-imizing the value of C(·,·)is then equivalent to obtaininga maximum likelihood estimate of the position,but without letting an outlier take the likelihood down to0.However,we found that choosing the threshold T isnot very intuitive,and that the results are sensitive to this choice.A different approach is to use a LMedS-type es-timator.At each point(x,y)we order the obtained val-ues{V P(x,y)|patches P}and we choose the Q’th smallest score:C(x,y)=Q th value in the sorted set{V P(x,y)|patches P}(3) The parameter Q is much more intuitive:it should be the maximal number of patches that we always expect to yield inlier measurements.For example,if we think that we are guaranteed that occlusions will always leave at least a quar-ter of the target visible,than we will choose Q to be25%of the number of patches(to be precise-we assume that at least a quarter of the patches will be visible).The additional computational burden when using esti-mate(3)instead of(2)is not signiﬁcant(the number of patches is less than40).ing the Integral HistogramThe algorithm that we have described requires multiple extractions of histograms from multiple rectangular regions.We extract histograms for each template patch,and then we compare these histograms with those extracted from mul-tiple regions in the target image.The tool enabling this tobe done in real time,as required by tracking,is the integral histogram described in[18].The method is an extension of the integral image data structure described in[25].The integral image holds at the point(x,y)in the image the sum of all the pixels containedin the rectangular region deﬁned by the top-left corner ofthe image and the point(x,y).This image allows to com-pute the sum of the pixels on arbitrary rectangular regionsby considering the4integral image values at the cornersFigure4.outer partof the regionof the region-in other words in(very short)constant timeindependent of the size of the region.In order to extract histograms over arbitrary rectangu-lar regions,in the integral histogram we build for each binof the histogram an integral image counting the cumula-tive number of pixels falling into that bin.Then by access-ing these integral images we can immediately compute thenumber of pixels in a given region which fall into every bin,and hence we obtain the histogram of that rectangular re-gion.Once the integral histogram data structure is computed(with cost proportional to the image(or actually search re-gion)size times the number of bins),extraction of a his-togram over a region is very cheap.Therefore evaluatinga hypothesis on the current object’s position(and scale)isrelatively cheap-basically it is the cost of comparing twohistograms.As noted previously,a tracking application of the integralhistogram was suggested in[18].We extend that examplewith the parts-based approach.4.1.Weighting Pixel ContributionsAn important feature in the traditional mean shift algo-rithm is the use of a kernel function which assigns lowerweights to pixels which are further away from the target’scenter.These pixels are more likely to contain backgroundinformation or occluding objects,and hence their contribu-tion to the histogram is diminished.However,when usingthe integral histogram,it is not clear how one may includethis feature.The following discrete approximation scheme may beused instead of the more continuous kernel weighting(seeFigure4).If we want to extract a weighted histogram inthe rectangular region R,we may deﬁne an inner rectangleR1and subtract the integral histogram counts of R1from those of R to obtain the counts in the ring R−R1.Thesecounts and the R1counts may be weighted differently andcombined to give a weighted histogram on R.Of course,anadditional inner rectangle R2may be used and so forth.The additional cost is the access and arithmetic involvedwith4additional pixels for every added inner rectangle.Formedium and large targets this cost is negligible when com-pared to trying to weigh the pixels in a straightforward man-ner.4.2.ScaleAs noted in[25,18],an advantage of the integral im-age/histogram is that the computational cost for large re-gions is not higher than the cost for small regions.This makes our search for the proper scale of the target not harder than our search for the proper location.Just as a hypothesis on the position(x,y)of the object deﬁnes a correspondence between a template patch P T and an image patch P I;(x,y),if we add a scale s to the hypoth-esis,it is straightforward toﬁnd the corresponding image patch P I;(x,y,s):we just scale the displacement vector of the patch and its height and width by s.The cost of extract-ing the histogram for this larger(or smaller)image patch is the same as for the same-size patch.We have implemented the standard approach(suggested in[8]and adopted by e.g.[4])of enlarging and shrinking the template by10%,and choosing the position and scale which give the lowest score in(3).The next section will present some results obtained with this approach.We remark that as noted in[7],this method has some limitations.For example,if the object being tracked is uniform in color,then there is a tendency for the target to shrink.In the case of partial occlusions of the target,we are faced with an additional dilemma:suppose that a uniform colored target is partially occluded.We get a good score by shrinking the target and locating it around the non-occluded part.Due to our robust approach,we also get a reasonable score by keeping the target at the correct size and locating it at the correct position,which includes some occluded parts of the target.However,there is no guarantee that the correct explanation will yield a better score than the partial expla-nation.A full treatment of this problem is out of the scope of the current work.5.ResultsNote:The full video clips are available at the authors’websites.We now present our experimental results.The tracker was run on gray scale images and the histograms we used contained16bins.Note that the integral histogram data structure requires an image for every bin in the histogram, and therefore on color images the application can become quite memory-consuming.We used vertical and horizontal patches as shown in Fig-ure5.The vertical patches are of half the template height, and about one tenth of the template’s width.The horizon-tal patches are deﬁned in a similar manner.Over all we had around36patches(the number slightly varies with template size because of rounding to integer sizes).We note thatthis choice of patches was arbitrary-we just tried it and found it was good enough.In the discussion we return to this issue.The search radius was set to7pixels from the previous target position.The template wasﬁxed at theﬁrst frame and not updated during the sequence(more on this in the discussion).We used the25’th percent quantile for the value of Q in(3).These settings of the algorithm’s parameters wereﬁxed for all the sequences.Theﬁrst two sequences(“face”and“woman”)show the robustness to occlusions.For these sequences we manually marked the ground truth(everyﬁfth frame),and plotted the position error of our tracker and of the mean-shift tracker. In both cases our tracker was not affected by the occlusions, while the mean-shift tracker did drift away.Figures6and 7show the errors with respect to the ground truth.Figure8 shows the initial templates and a few frames from these se-quences.Note the last frame of the woman sequence(sec-ond row)where one can see an example of the use of spatial information(seeﬁgure caption also).We additionally note that we ran our tracker on these ex-amples with only a single patch containing the whole tem-plate,and it failed(this is actually the example tracker de-scribed in[18]).The next sequence-“living room”in Figure9-shows performance under partial pose change.When the tracked woman turns her head the mean shift tracker drifts,and then together with an occlusion it gets lost.Our tracker is robust to these interferences.In Figure10we present more samples from three more sequences.In these frames we marked only our tracker.The ﬁrst two sequences are from the CA VIAR database[1].The ﬁrst is an occlusion clip and the second shows target scale changes.The third sequence is again an occlusion clip.We bring it to demonstrate how our tracker uses spatial informa-tion(which is generally lost in histogram-based methods). Both persons have globally similar histograms(half dark and half bright).Our tracker“knows”that the bright pixels should be in the upper part of the target and therefore does not drift to the left person when the two persons are close.6.Discussion and ConclusionsIn this work we present a novel approach(“FragTrack”) to tracking.Our approach combines fragments-based repre-initial template frame 222frame 539frame 849initial template frame 66frame 134frame 456Figure 8.Occlusions -frames from “face”and “woman”sequences.Our tracker -solid red.Mean-shift tracker -dashed blue.Note in frame 456how the spatial information -bright in the upper part,dark in the lower part -helps our tracker.The mean-shift tracker which does not have this information chooses a region witha dark upper part and a bright lower part.initial template frame 29frame 141frame 209Figure 9.Pose change and occlusions -frames from “living room”sequence.Our tracker -solid red.Mean-shift tracker -dashed blue.40506070Position error w.r.t. ground truthn p i x e l s )our trackermean shift trackerground truth.Our tracker -solid red.Mean shift -dashed blue.Please see videos for additional impression sentation and voting known from the recognition literature,with the integral histogram tool.The result is a real time tracking algorithm which is robust to partial occlusions and 2530354045Position error w.r.t. ground truthn p i x e l s )our trackermean shift trackermarked ground truth.Our tracker -solid red.Mean shift -dashed blue.Please see videos for additional impressionpose changes.In contrast with other tracking works,our parts or frag-ments approach is model-free:the fragments are choseninitial template frame48frame82frame110initial template frame30frame100frame180initial template frame35frame65frame90Figure10.Additional examples.Theﬁrst two rows are from the CA VIAR database.No background subtraction/frame differencing was used.In the last row note again the use of spatial information-both persons have the same global histogram.arbitrarily and not by reference to a pre-determined parts-based description of the target(say limbs and torso in hu-man tracking,or eyes and nose in face tracking).Without the integral histogram’s efﬁcient data structure it would not have been possible to compute each fragment’s votes map.On the other hand,without using a fragments-based algorithm,robustness to partial occlusions or pose changes would not have been possible.We demonstrate the validity of our approach by accu-rate tracking of targets under partial occlusions and pose changes in several video clips.The tracking is achieved without any use of color information.There are several interesting issues for current and fu-ture work.Theﬁrst is the question of template updating. We want to avoid introduction of occluding objects into the template.The use of the various fragments’similarity scores may be useful towards meeting this goal.A second issue is the partial versus full explanation dilemma described earlier and in[7]when choosing scale. This dilemma is even more signiﬁcant under partial occlu-sions.Lastly,we may also consider disconnected rectangular fragments.It would be interesting toﬁnd a way to choose the most informative fragments[24]with respect to the tracking task.References[1]Caviar datasets available at/vision/caviar/caviardata1/.[2]S.Agarwal,A.Awan,and D.Roth.Learning to detect ob-jects in images via a sparse,part-based representation.IEEE Transactions on Pattern Analysis and Machine Intelligence, 20(11):1475–1490,2004.[3] D.Beymer,P.McLauchlan,B.Coifman,and J.Malik.Areal-time computer vision system for measuring trafﬁc pa-rameters.In Proc.IEEE Conf.on Computer Vision and Pat-tern Recognition(CVPR),1997.[4]S.Birchﬁeld and S.Rangarajan.Spatiograms vs.histogramsfor region based tracking.In Proc.IEEE Conf.on Computer Vision and Pattern Recognition(CVPR),2005.[5]O.Boiman and M.Irani.Detecting irregularities in imagesand video.In Proc.IEEE Int.Conf.on Computer Vision (ICCV),2005.[6]G.Bradski.Real time face and object tracking as a compo-nent of a perceptual user interface.In Proc.IEEE WACV, pages214–219,1998.[7]R.Collins.Mean shift blob tracking through scale space.InProc.IEEE Conf.on Computer Vision and Pattern Recogni-tion(CVPR),pages II:234–240,2003.[8] aniciu,R.Visvanathan,and P.Meer.Kernel basedobject tracking.IEEE Transactions on Pattern Analysis and Machine Intelligence,25(5):564–575,2003.[9]W.Conover.Practical Nonparamteric Statistics.Wiley,1998.[10]Z.Fan,Y.Wu,and M.Yang.Multiple collaborative kerneltracking.In Proc.IEEE Conf.on Computer Vision and Pat-tern Recognition(CVPR),2005.[11] D.Forsyth and puter Vision:A Modern Ap-proach.Prentice-Hall,2001.[12] B.Georgescu and P.Meer.Point matching under large imagedeformations and illumination changes.IEEE Transactions on Pattern Analysis and Machine Intelligence,26:674–689, 2004.[13]G.Hager and P.Belhumeur.Efﬁcient region tracking withparamteric models of geometry and illumination.IEEE Transactions on Pattern Analysis and Machine Intelligence, 20(10):1125–1139,1998.[14]G.Hager,M.Dewan,and C.Stewart.Multiple kernel track-ing with ssd.In Proc.IEEE Conf.on Computer Vision and Pattern Recognition(CVPR),2004.[15]M.Isard and A.Blake.Condensation:Conditional densitypropagation for visual tracking.Int.Journal of Computer Vision(IJCV),29(1):5–28,1998.[16]K.Mikolajczyk,C.Schmid,and A.Zisserman.Humandetection based on a probabilistic assembly of robust part detectors.In Proc.Eurpoean Conf.on Computer Vision (ECCV),2004.[17] A.Mohan, C.Papageorgiou,and T.Poggio.Example-based object detection in images by components.IEEE Transactions on Pattern Analysis and Machine Intelligence, 23(4):349–361,2001.[18] F.Porkili.Integral histogram:A fast way to extract his-tograms in cartesian spaces.In Proc.IEEE Conf.on Com-puter Vision and Pattern Recognition(CVPR),2005.[19]Y.Rubner.Code available at /∼rubner/.[20]Y.Rubner,C.Tomasi,and L.Guibas.The earth mover’sdistance as a metric for image retrieval.Int.Journal of Com-puter Vision(IJCV),40(2):91–121,2000.[21] C.Schmid and R.Mohr.Local gray-value invariants for im-age retrieval.IEEE Transactions on Pattern Analysis and Machine Intelligence,1997.[22] C.Shen,M.Brooks,and A.Hengel.Fast global kernel den-sity mode seeking with application to localisation and track-ing.In Proc.IEEE Int.Conf.on Computer Vision(ICCV), 2005.[23]L.Sigal et al.Tracking loose-limbed people.In Proc.IEEEConf.on Computer Vision and Pattern Recognition(CVPR), 2004.[24]S.Ullman,E.Sali,and M.Vidal-Naquet.A fragment-basedapproach to object representation and classiﬁcation.In Proc.IWVF4,LNCS2059,pages85–100,2001.[25]P.Viola and M.Jones.Robust real time object detection.In IEEE ICCV Workshop on Statistical and Computational Theories of Vision,2001.[26] C.Yang,R.Duraiswami,and L.Davis.Efﬁcient mean-shifttracking via a new similarity measure.In Proc.IEEE Conf.on Computer Vision and Pattern Recognition(CVPR),2005.。

3-D inversion of magnetic data

GEOPHYSICS, VOL. 61, NO. 2 (MARCH-APRIL 1996); P. 394-408, 18 FIGS.3-D inversion of magnetic dataYaoguo Li* and Douglas W. Oldenburg*ABSTRACTWe present a method for inverting surface magneticdata to recover 3-D susceptibility models. To allow themaximum flexibility for the model to represent geologi-cally realistic structures, we discretize the 3-D modelregion into a set of rectangular cells, each having aconstant susceptibility. The number of cells is generallyfar greater than the number of the data available, andthus we solve an underdetermined problem. Solutionsare obtained by minimizing a global objective functioncomposed of the model objective function and datamisfit. The algorithm can incorporate a priori informa-tion into the model objective function by using one ormore appropriate weighting functions. The model forinversion can be either susceptibility or its logarithm. Ifsusceptibility is chosen, a positivity constraint is imposedto reduce the nonuniqueness and to maintain physicalrealizability. Our algorithm assumes that there is noremanent magnetization and that the magnetic data areproduced by induced magnetization only. All minimiza-tions are carried out with a subspace approach whereonly a small number of search vectors is used at eachiteration. This obviates the need to solve a large systemof equations directly, and hence earth models with manycells can be solved on a deskside workstation. Thealgorithm is tested on synthetic examples and on a fielddata set.Magnetic surveying has been used widely over the years,INTRODUCTIONresulting in a great amount of data with enormous area1 coverage. Magnetic data have been used for mapping geolog-ical structures, especially in the reconnaissance stage of explo-ration, but when used in detailed prospecting, robust and efficient inversion algorithms must be used. However, a prin-cipal difficulty with the inversion of the potential data is the inherent nonuniqueness. By Gauss’ theorem, if the field distri-bution is known only on a bounding surface, there are infinitely many equivalent source distributions inside the boundary that can produce the known field. Any magnetic field measured on the surface of the earth can be reproduced by an infinitesimally thin zone of magnetic dipoles beneath the surface. From a mathematical perspective, this means there is no depth reso-lution inherent in magnetic field data. A second source for nonuniqueness is the fact that magnetic observations are finite in number and are inaccurate. If there exists one model that reproduces the data, there are other models that will repro-duce the data to the same degree of accuracy. The severity of the nonuniqueness problem for magnetic data is illustrated in Figures l-3. (The gray scale in all figures indicates suscepti-bility in SI units for model sections and magnetic data in nT for data plots.) A 3-D dipping prism of uniform susceptibility in Figure 1 produces the surface magnetic field shown in Figure 2, which consists of 441 data. Slices of a 3-D susceptibility model that adequately reproduces the 441 data are shown in Figure 3. That result, however, bears little resemblance to the true model. Susceptibility is concentrated near the surface and displays zones of negative values. This mathematical model solution provides little information about the true structure that is useful.Faced with this extreme nonuniqueness, previous authors have mainly taken two approaches in the inversion of magnetic data. The first is parametric inversion, where the parameters of a few geometrically simple bodies are sought in a nonlinear inversion and values are found by solving an overdetermined problem. This methodology is suited for anomalies known to be generated by simple causative bodies, but it requires a great deal of a priori knowledge about the source expressed in the form of an initial parameterization, an initial guess for param-eter values, and limits on the susceptibility allowed (e.g., Bhattacharyya, 1980; Zeyen and Pous, 1991). Nonuniqueness is not generally an issue because only a small subset of possible models is considered due to the restrictive nature of the inversion algorithm. A related, but unique, approach in Wang and Hansen (1990) assumes polyhedronal causative bodies andPresented at the 63rd Annual International Meeting, Society of Exploration Geophysicists. Manuscript received by the Editor May 2, 1994; revised manuscript received June 29, 1995.*UBC-Geophysical Inversion Facility, Dept. of Geophysics and Astronomy, University of British Columbia, 129-2219 Main Mall, Vancouver, BC V6T 1Z4, Canada.© 1996 Society of Exploration Geophysicists. All rights reserved.3943-D Inversion of Magnetic Data395inverts for the position of the vertices of these bodies using the spectrum of the magnetic data. The method is general in principle but has difficulties both in constructing the causative bodies from the recovered vertices and in obtaining the susceptibility distribution.In the second approach to inverting magnetic data, the earth is divided into a large number of cells of fixed size but of unknown susceptibility. Nonuniqueness of solution is recog-nized and the algorithm produces a single model by minimizing an objective function of the model subject to fitting the data. Green (1975) minimizes a weighted model norm with respect to a reference model, and this allows the interpreter to guide the inversion by varying the weighting according to the avail-F IG. 1. Slices through a 3-D magnetic susceptibility model composed of a dipping slab in a nonsusceptible half-space. The slab is buried at a depth of 50 m and extends to 400-m depth at a dip angle of 45° . The gray scale indicates the value of able information. Last and Kubik (1983) choose to minimize the total volume of the causative body so that the final model is compact and structurally simple. Guillen and Menichetti (1984) minimize the moment of inertia of the causative body with respect to the center of gravity or an axis passing through it. Their inversion result is guided by the estimate of the central depth and dip of the causative body. These approaches have merit but they are not flexible enough to handle problems we are concerned with. This is especially true of methods that attempt to collapse the anomalous susceptibility into a single body; such a solution is rarely an adequate representation of geologic structure.In our inversion approach, we first make a decision about the variable in which the interpretation is to be made, that is, whether susceptibility, log susceptibility, or some function of susceptibility is sought. Next, we form a multicomponent objective function that has the flexibility to generate different types of models. The form of this objective function is such that it can correct for the undesirable aspects of the mathematically acceptable model in Figure 3, namely-the concentration of susceptibility near the surface, the excessive structure, and the existence of negative susceptibilities. Our objective function incorporates an optional reference model so that the con-structed model is close to that. It penalizes roughness in three spatial directions, and it has a depth weighting designed to distribute the susceptibility with depth. Additional 3-D weight-ing functions in the objective function can be used to incorpo-rate further information about the model. Such information might be available from other geophysical surveys, geological data, or the interpreter’s qualitative or quantitative under-standing of the geologic structure and its relation to the magnetic susceptibility. These 3-D weighting functions can also be used to answer questions about the existence of suscepti-bility features found from previous inversions. Negative sus-ceptibilities are prevented by making a transformation of F IG. 2. The total field anomaly produced by the slab model in Figure 1. The inducing field has direction I = 75° and D = 25°and a strength of 50 000 nT. Uncorrelated Gaussian noise, with a standard deviation of 2% of the datum magnitude plus 1 nT, is added to the data. The gray scale indicates the magnetic anomaly in nT.magnetic susceptibility in SI units.by inverting a field data set over a copper-gold porphyry deposit and a subsequent discussion.396Li and Oldenburgvariables and solving a nonlinear inverse problem. The numer-ical solution for the inversion is accomplished by dividing the earth into a large number of cells so that relatively complex geologic bodies can be constructed. The computational diffi-culties often encountered in solving large matrix systems are avoided by working explicitly with a generalized subspace algorithm.The paper begins by outlining our inversion methodology and empirically estimating parameters for the depth weighting based upon synthetic inversion of single 3-D prisms. Data from two synthetic models are then inverted. The paper concludesEach magnetic anomaly datum observed above the surface can be evaluated by calculating the projection of the anoma-lous magnetic field onto a given direction. Let the source region be divided into a set of rectangular cells by an orthog-onal 3-D mesh and assume a constant magnetic susceptibility valueThe magnetic anomaly at a location on, or above, the surface is related to the subsurface susceptibility by a linear relationshipINVERSION METHODOLOGYwhich quantify the contribution of a unit suscep-tibility in thejth cell to the ith datum. Closed form solutions for is theprojection onto a given direction of the magnetic field that is produced by a rectangular cell, so equation (1) is valid for computing different magnetic anomalies. For example, a pro-jection onto the vertical direction gives the vertical magnetic anomaly while a projection onto the ambient geomagnetic field direction yields the total magnetic anomaly. Thus, the method presented here can be used to invert different types of mag-netic data and in the following, we simply refer to them as the magnetic data with the understanding that it is direction specific.F IG . 3. The susceptibility model constructed by minimizingandbut anyfunctionor any monotonicfunction3-D Inversion of Magnetic Data 397(2)where functions w s , w x , w y ,and w z are spatially dependent weighting functions whilerefers collectively to the remaining three terms thatinvolve variation of the model in three spatial directions.The objective function in equation (2) has the flexibility of constructing many different models. The reference model m 0may be a general background model that is estimated from previous investigations, or it could be the zero model. The reference model would generally be included in for the surface magnetic datadecay with depth. It is for this reason that an inversion thatminimizesdv subject to fitting the data will generate a susceptibility that is concentrated near the surface. To counteract the geometric decay of the kernels and to distribute susceptibility with depth, we introduce a weightingof the forminto The values of(3)and we assume that the contaminating noise on the data is independent and Gaussian with zero mean. Specifyingwherea chi-squaredvariable distributed with Ndegrees of freedom. Accordinglyis our target misfit and(4)model. The weighting functions w x , w y , and w z can be designed to enhance or attenuate structures in various regions in the model domain. If geology suggests a rapid transition zone in the model, then a decreased penalty for variation can be put there, and the constructed model will exhibit higher gradients provided that this feature does not contradict the data. There-fore, the reference model and four 3-D weighting functions allow for the incorporation into the inversion of additional information other than the magnetic data. The additional information can be from previous knowledge about the sus-ceptibility, from other geophysical surveys, or from the inter-preter’s qualitative or quantitative understanding about the geologic structure and its relation to susceptibility. When thiswhere m and m 0 are M-length vectors. The individual matricesare calculated straightforwardly once the model mesh and the weighting functions w s , w x , w y , w z , and w ( z) are defined (see Appendix). The cumulative matrixis then formed. For our formulation, the matrix398Li and Oldenburgof variables. Whether or not the transformation is required depends upon the relationship between m iandandis a diagonal matrix with elementsyields(7)At each iteration we desire a perturbation that minimizes equation (4) subject to generating a data misfit of whereyields(9)Differentiating with respect to the coefficients a yields the final equations(10)We note that the matrixthat yields the target misfit for thatiteration. If the target misfit cannot be reached, then the valueofvalues. Once the optimum value ofand the model perturbation. This iterative process is continued until the final expected data misfit is achieved and the model objective function undergoes no significant decrease with successive iterations. Subspace vectors v i are generated mainly from the gradients of the data and model objective functions.The data are grouped to form subobjective functions of misfit,and a steepest descent vector corresponding to each subobjec-tive function is used as a subspace vector. Partitioning of the data can be formed by grouping data that are spatially close, or by grouping data such that each group has approximately the same contribution to the total data misfit. Both approaches have worked well. The model objective function is partitioned and the gradient vector associated with each of the four components in the model objective function provides addi-tional subspace vectors. In addition, a constant vector is always included, and the selected subspace vectors are orthonormal-ized before being used in the search. More details on the implementation of the subspace method for the linear inverse problem can be found in Oldenburg and Li (1994).The final item of practical importance is the specification of the mapping needed to ensure positivity of susceptibility. The positivity is required since we are dealing only with induced magnetization, and the presence of negative susceptibility is negligible in practical geophysical applications. Although our formalism permits the minimization of m =and m=we set p = m and hence the matrixwe use the two-stage mappingproposed in Oldenburg and Li (1994). It is composed of an exponential segment and a straight line. The two segments are joined together such that the mapping and its first derivativeare both continuous. The mapping is given byis selected to be small enough suchthat susceptibilities smaller thanand hence p l are chosen so that the ratiodoes not exceed about two orders of magnitude. This prevents the elements F ii from becoming too disparate. We note that the ith row ofis essentially annihilated and there willbe no possibility of adjusting the value of the ith cell. However,if the ratio is too small, the flexibility in the mapping will be restricted and this affects the convergence rate of thealgorithm. In the limit that3-D Inversion of Magnetic Data399DEPTH WEIGHTINGIt is well known that static magnetic data have no inherent depth resolution.For instance, when minimizingstructures tend to concentrate near the surface regardless of the true depth of the causative bodies. In terms of model construction, this is a direct manifestation of the nature of the kernels whose amplitudes rapidly diminish with depth.The tendency to put structure at the surface can be overcome by introducing a depth weighting to counteract this natural decay. Intuitively, a weighting that approximately compensates for the decay gives cells at different depths equal probability to enter into the solution with a nonzero susceptibility. Before proceeding with the details of the weighting function for magnetic inversion, we illustrate the necessity, and effective-ness, of such a weighting function using a simple 1-D problem.Consider a set of data d = ( d 1, , . . . , d N ) T generated from theequation(12)since themodel will be a linear combination of the kernels, i.e.,F IG . 4. A 1-D example showing the use of a weighting function in the inversion procedures to counteract the natural decay in the kernel function. In all panels the dashed line shows the true model. Panels (a) and (b) show, for the two different true models ,respectively, the model constructed using the original kernel functions with the decaying factor e -az . Notice the shift of the recovered model towards the small z region. Panels (c) and (d) show the weighted models recovered by applying a weighting function w ( z ) = e -az/2.They are better representations of the true model.m w ( z ) is theweighted model. Then the inverse problem is solved by mini-mizing(19)are shown in Figure 6. Eachpanel in the figure is the cross-section through the center of the model obtained by inverting the data set produced by a cube at a different depth. They are rather good recoveries in terms of source depth, which is indicated by the superimposed outline of the true body in each section.In the above analysis we have established a practical way for estimating an appropriate depth weighting function that dis-tributes the susceptibility more uniformly with depth. The weighting is valid when the model objective function consistsonly of In general, we like to include a penalty against roughness and thereby produce a model that is smooth. To incorporate the above weighting scheme in the spatial varia-tions, we make the following argument. Since minimizing3-D Inversion of Magnetic Data401(20)can yield reasonable results.PRACTICAL ASPECTS OF DATA PREPARATIONThe data used in the inversion are the residual data obtainedby subtracting a regional field from the initial observation. Theinversion algorithm has been developed under the assumptionsthat the surface magnetic anomaly is produced by the inducedmagnetization only and that there are no remanent magneti-zation or demagnetization effects present. Incorrect removal ofregional field, or any deviation from the above assumptions, isexpected to cause a deterioration in the inversion results.Furthermore, the susceptibility distribution is mathematicallyrepresented by a piece-wise constant function defined on auser-specified grid of cells. Magnetic sources, however, have awide range of physical sizes. In some cases, source dimensionswill be significantly smaller than the size of cells in themathematical model. If measurements are taken close to sucha source, the resulting anomaly will have a width that issignificantly smaller than that produced by a single cell in themathematical model and this may produce artifacts. We ame-liorate this problem by inverting data that have been upwardcontinued to a height approximately equal to the width of thesurface cells in the model. We arrive at this conclusion from anumerical experiment. We first generate the magnetic fieldthen themisfit functional,(21)F IG. 7. The misfit between magnetic field as a result of a smallcubic source and the field as a result of a larger cubic modelcell having a best fitting susceptibility. The numbers indicatethe ratio of the cell width. The misfit is plotted as a function ofthe observation height normalized by the width of the modelcell. Note that the misfit decreases rapidly until the height isapproximately equal to the width of the model cell, and that itchanges slowly thereafter.402Li and Oldenburgcan be computed, where= 0.1, 0.2, 0.4. We note that r ( h ) decreases rapidly until h=0.0002 andand using m=The depth weighting is applied to all terms, as in equation (20).The inversion uses 54 subspace vectors and achieves the expected misfit in 13 iterations. The recovered model is shown in Figure 9. It is smoother, has a slightly lower amplitude than the model in Figure 8, and it recovers the essential features of the true model such as the depth and dip angle.It is observed, in this example and in other synthetic and field test examples, that minimizing either the first term in themodel objective function in equation (20),can be obtained at less computational cost. Further-F IG. 8. Model obtained from inverting the data shown in Figure 2 by minimizing only3-D Inversion of Magnetic Data403 more, the depth weighting in this case is rather well supportedby mathematical analysis whereas it is an argued extension forthe three roughness components. Therefore, a reasonableapproach to inverting field data might be a two-step process.The data can be inverted first by minimizingandandas the model. It is not possible to incorporate a zero susceptibility as the reference model, so we minimize an objective function consisting ofSinceas the model and minimizing404Li and Oldenburgtop and dipping angle. The anomaly terminates at a shallowerdepth than the true model and has a nearly horizontal exten-sion to the left. As an exact comparison, Figure 10c is thesusceptibility model obtained by minimizingand3-D Inversion of Magnetic Data405tive values that result from dipping bodies or inclined inducing field, or both. Without positivity, the constructed susceptibility is often negative and the dipping bodies appear more vertical.Recovery of correct dip and, to some extent, depth to the top of the anomalous body, are often the result of invoking positivity. Once the positivity is imposed, it is no longer true that an equivalent stratum that reproduces the data exists at any depth. Therefore, cells of anomalous susceptibility cannot be placed arbitrarily close to the surface, and no equivalent source can be constructed with negative susceptibilities. This restricts the class of admissible models and, consequently,reduces the nonuniqueness.F IG . 13. The susceptibility model recovered from the data shown in Figure 12. It is seen that both the top and bottom block of the true model are recovered and the strike direction and length are well defined.FIELD EXAMPLEAs the final example, we invert field data taken over a copper-gold porphyry deposit at Mt. Milligan in central British Columbia. The host rocks for the deposit are early Mesozoic volcanic and sedimentary rocks and contain intrusive monzo-nitic rocks that have accessory magnetite. Porphyry-style alter-ation and copper-gold mineralization are contemporaneous with the intrusive events. The copper and gold are known to be concentrated in the potassic alteration assemblage, which is mainly around the contact of the monzonite intrusions and may extend outward and into fractured volcanic rocks. Among other minerals, magnetite is one of the strong indicators of the potassic alteration. Ground magnetic data are acquired in the region at 12.5-m spacing along lines in the east direction and spaced 50 m apart. Our study of the data set has focused on a 1.2 km x 1 km area, which covers a large monzonite body known as the MBX stock and contains a reasonably isolated set of magnetic anomalies. Fairly detailed information about the geology is available through a major drilling program, but no susceptibility logs were available.Magnetic data from a larger area were first upward contin-ued to 20 m. A regional field was then defined and removed from the upward continued data. The continuation operation suppresses the noise in the data and also facilitates the discretization of the topographic surface for the model so that all observation points remain above the discretized surface.Although the original data were collected at 12.5-m spacing,we use the data at 25-m spacing. This yields 1029 data points at varying elevations. Figure 16 shows the data contoured accord-ing to their horizontal locations. The direction of the inducing field is I = 75° and D = 25.73°. Several major magnetic highs are observed in the map. However, the influence of anomalies adjacent to the map is also visible along the edges. We choose a model domain that is horizontally larger than the data area,coincides at the top with the highest point on the topographic surface, and extends to 450-m depth. The model is discretized horizontally at a 25-m interval beneath the area of data. In theF IG . 14. The surface total field anomaly produced by the faulted slab in Figure 11 under an inducing field at I = 0° and D = 45°. Uncorrelated Gaussian noise is added to the data.406Li and Oldenburgvertical direction, the first 100 m is divided at a 12.5-m interval so that the surface can be adequately discretized onto the model mesh. Below the depth of 100 m, an interval of 25 m is used. This results in a mesh with 52 x 44 x 22 cells. Once the mesh is defined, the topography is discretized onto it. The 43 428 cells below this surface define the susceptibility model,and the inverse problem is therefore formalized by inverting 1029 data to recover the susceptibilities in those cells. The depth weighting is referenced to the top of the model domain.Each datum is assumed to have an error whose standard deviation is equal to 5% of its magnitude plus 10 nT. The error estimate includes not only the repeatability of the instrument reading but also the geological noise and errors introduced by the inaccurate recording position and by separating the anom-alous field from the initial total field measurements. OneF IG . 15. The susceptibility model recovered from the data shown in Figure 14. This model is similar to that shown in Figure 13.hundred subspace vectors generated by dividing the data map into small subareas are used in the inversion. We use anonlinear mapping with = 0.02. The recovered model is shown in Figure 17 as one plan-section and three cross-sections. From the plan-section, two concentrated susceptibility highs are observed in the central region. Sur-rounding them are three linear anomalies trending northeast.In the cross-sections, the major anomalies are seen at moder-ate depths but there is considerable variation in the depth to the top. There are also smaller anomalies extending to the surface. In general, there are more detailed structures near the surface and the model becomes increasingly smooth at greater depths. As required by the objective function, there is no excessive structure associated with each unit of high suscepti-bility region. Comparison with drill logs indicates that the recovered magnetic susceptibility highs are mostly associated with the monzonite intrusions and with faults or fracture zones.Figure 18 compares the recovered susceptibility model with the geology (Cam DeLong, personal communication) in the cross-section at x = 600 m. The large susceptibility high is spatially well-correlated with the MBX stock and reflects the initial magnetite content in the intrusion. Two smaller susceptibility highs are present east of the stock. The high at y = 650 m coincides with the boundary of stock and porous trachytic units while the high at y =900 m coincides with the upper portion of the Rainbow dyke. These are locations of the most intensive potassic alterations and the susceptibility highs are indicative.of the magnetite produced by the alteration process. Over all,this is a rather encouraging result.CONCLUSIONWe have developed an algorithm to invert surface magnetic data for general 3-D susceptibility distributions. Although we have illustrated the algorithm using examples on the scale pertinent to mining applications, the method is general and applicable to problems on different scales ranging from envi-ronmental to regional investigations. To overcome the inher-ent nonuniqueness, we obtain the solution by minimizing aF IG . 16. The extracted total field anomaly from ground mag-netic data at Mt. Milligan Copper-gold porphyry deposit. The data are contoured according to their horizontal locations in this map, although thev are at different elevations.。

山东省枣庄市2023-2024学年高一下学期7月期末英语试题

山东省枣庄市2023-2024学年高一下学期7月期末英语试题一、阅读理解July is just around the corner. As you look forward to travelling or having your holidays to the beach, an outdoor theatre may also be a good choice. There are plenty of outdoor theatres to choose from across the UK.Storyhouse Theatre, ChesterEvery year in July, Storyhouse theatre builds an entire amphitheatre (圆形剧场) in Grosvenor Park. This year sees an eclectic trio: The Gangs of New York, The Importance of Being Earnest and The Wizard of Oz. You will be most excited by the first: a new adaptation written by Kieran Lynn and directed by John Young.Thorington Theatre, SuffolkOpening in 2021, Thorington is built in a natural amphitheatre hidden in the Suffolk woodlands. This year’s programme includes some family favourites such as Teddy Bear’s Picnic and The Little Mermaid, as well as Shakespeare’s The Tempest and A Midsummer Night’s Dream.Minack Theatre, CornwallBuilt into a cliff face in Porthcurno, you hardly need an excuse to visit this theatre. It will be an unforgettable experience. This year sees touring productions of Little Shop of Horrors, The Massive Tragedy of Madame Bovary among other things. If you want a show particularly fitting for this unique surrounding, check out The Pirates of Penzance playing in September.Pitlochry Festival Theatre, Highland PerthshireThroughout most of the year, the Pitlochry Festival Theatre’s indoor auditorium and studio serve as their regular performance spaces. But in summer, you can see equally lavish productions at the amphitheatre, nestled in the woods and overlooking Ben-Y-Vrackie mountain. This year they’ll be staging Dido and Aeneas, and The Secret Garden, the perfect story for this lush garden stage.1．What do the theatres have in common?A．They offer outdoor activities.B．They are built in woodlands.C．They are only open in summer.D．They put on open-air performances.2．In which of the following can you enjoy a Shakespeare play?A．Storyhouse theatre.B．Thorington Theatre.C．Minack Theatre.D．Pitlochry Festival Theatre.3．What do you think of the plays staged in Minack Theatre?A．Peaceful.B．Family-friendly.C．Thrilling.D．Humorous.For her novel Brotherless Night, the writer V. V. Ganeshananthan has won this year’s Carol Shields Prize for Fiction. This is the second year of the prize, which awards English-language writing by women authors. Winners of the award receive $150,000.Brotherless Night centers on a young woman named Sashi, in 1981, who wants to be a doctor. But over the next decade, her dream takes a different path as she watches those around her, including her four beloved brothers, who died in Sri Lanka’s thirty-year civil war. Based on over a decade of research, in fearless writing, Ganeshananthan captures angry mothers marching to demand news of their disappeared sons; a young student attending the hunger strike for equality; and a female reading group that tries to seek for justice. She explores ordinary people’s life in the conflicts.In a statement announcing the win, the prize jury called the book “ambitious and beautifully written” and praised Ganeshananthan’s characters for asking readers to “consider how history is told, whom it serves, and the many truths it leaves out.” The publisher reviewed the book: “It is a heartbreaking portrait of one woman’s moral journey, and a testament (证明) of both the impact of war and the bonds of home.”The Prize is named after Canadian Pulitzer-Prize winning author Carol Shields, who died in 2003. The first novel awarded last year was When We Were Sisters by Fatimah Asghar. The money awarded is higher than most other literary prizes. Winners of the Pulitzer Prize, for instance, receive $15,000. On top of the money, winners of the Carol Shields prize win a legal permission to live at the Fogo Island Inn, on the coast of Newfoundland and Labrador.Brotherless Night stood out from the five shortlisted books as the winner. Other finalists will receive $12,500.4．What does the novel Brotherless Night focus on?A．The cruelty of war.B．Sashi’s career choice.C．The social equality.D．The impacts of war.5．What is the prize jury’s comment on the book’s characters?A．They provide food for thought.B．They are always considerate.C．They are ambitious people.D．They are fearless fighters.6．What do we know about Carol Shields Prize for Fiction?A．It offers the best prize money.B．It is part of the Pulitzer Prize.C．It only awards a cash prize.D．It awards women authors.7．What is the purpose of the text?A．To introduce a prize-winning novel.B．To show a woman’s literary path.C．To share a heartbreaking story.D．To compare two literary prizes.A monarch butterfly landed on the palm of my open hand. I put my hand high above my head. The butterfly took off, flying into the sky and disappearing.That moment was in 1993. It was the first time I had ever tagged a butterfly. I got hooked. Over the years, I observed its change from egg to adult. I watched with eyes wide when the caterpillar would start to shed its skin and show its inner green body. My passion for science inspired by these small insects continued to Kenyon College in Ohio. There I was one of the few girls who majored in biology.I got involved in a long-term program fueled by generations of energetic volunteers. They tagged monarchs, monitored their migration south, and helped to give lectures at the local state park. It helped show patterns in monarch migration. Monitoring monarchs in the same location, year after year, allowed us to associate climate change with increasing delayed migrations, which had put the monarchs at risk.In another program, we visited a monarch reserve in March 2007. There, we tagged more than 3,000 monarchs, talked to hundreds of interested visitors, and witnessed the amazing movement of monarchs. It was a transformational experience. More and more visitors came every spring. The monarchs bring in thousands of tourists each year, helping the local economy and providing new ideas to protect the remaining forest.Monarch butterflies, and science programs supporting them, helped draw me into science over 20 years ago. Other projects like Audubon’s Christmas Bird Count have also inspired other young students to embark on careers in science. Engaging in any manner of projects, like monitoring sea level rise, contributes to science and helps get students of any age outdoors.Remember: science isn’t just for scientists.8．What motivated the author to study biology in the college?A．Playing a butterfly game.B．The monarch’s migration.C．Her interest in butterflies.D．Feeding monarchs at home.9．What might be a cause of monarch’s delayed migrations?A．Loss of forests.B．Lack of food sources.C．Climate change.D．Tourism development.10．What does the author think of their visit to the monarch reserve in 2007?A．Well-organized.B．Rewarding.C．Laborious.D．Boring.11．Why does the author mention Audubon’s Christmas Bird Count?A．To show who are real scientists.B．To prove her predictions.C．To advocate animal protection.D．To show its inspiring effect.Deceleration isn’t really in the runner’s vocabulary. For many of the people who do it, from Olympic champions to 5K enthusiasts, running is the pursuit of speed itself; a sport defined by personal bests, competition and striving. Slow? That’s a four-letter word.Until quite recently, slow running has become “A Thing”, backed not just by wellness experts on Instagram, but also by a growing number of coaches, amateur runners and exercise scientists, too. The thinking is that going slow could be a fast way to enjoy the benefits of exercise.Slow running is usually defined as a pace at which you can comfortably hold a conversation. Think of it as an effort of 4 or 5 on a scale of 1 - 10, where 10 is an all-out sprint (冲刺). If you know your sports science, it’s referred to as ‘zone 2 exercise’ and it’s a physiological sweet spot that can improve and extend your life.So, what makes the unhurried approach so healthful? As well as improving the strength and pumping capacity of your heart, slow running can avoid metabolic diseases and encourage your body to use fat for energy. Slow runners also recover faster and are less likely to suffer tiredness or injuries from overtraining. They’re also more likely to feel good.“There are huge positives for emotional health,” says Gordon, an exercise physiologist atAnglia Ruskin University in southeast England. “The benefits for things like mood state, depression and anxiety don’t really decrease any more if we increase the exercise intensity. And then there’s the social aspect. One of the things to emphasize with slow running is, you can actually have a conversation!” Gordon believes that promoting slow running might encourage more people to exercise and stick with it, partly because you can do it with friends and partly because there’s no pressure to perform.12．What is the most important for a runner on the sports field?A．Speed.B．Health.C．Interest.D．Enjoyment. 13．What does the underlined word “backed” mean in Paragraph 2?A．Explained.B．Defined.C．Supported.D．Proved. 14．What are the last two paragraphs mainly about as to slow running?A．Its definition.B．Its benefits.C．The training.D．Its popularity. 15．What does Gordon say about slow running?A．It benefits a lot to mental health.B．It is key to increase the intensity.C．It offers a chance to make friends.D．It is no easy work to stick with it.Every culture has its own music. 16 All types of music have one thing in common: it brings people together.There are many festivals held in various communities. 17 Without music, a celebration will be effectively incomplete. Music allows us to dance and be completely ourselves in front of our peers. When music is playing and people are dancing, you feel a sense of belonging to your culture.Music is always present in our lives. It can be a huge part of our life no matter where we live or how old we are. Our parents play us music or sing to us when we are young. People schedule a time to relax and listen to their favorite music. 1819 There’s a reason why parents sing to their babies before they’re born. They will be able to learn a language by listening to music. The alphabet, taught through a song, is one of the most important skills you learned as a child. To be sure, learning a language through song is easier than trying to memorize a sentence in a completely different language.Music also assists us in discovering our identities. 20 As they grow older, theybegin to have our own musical tastes. That is often their first act of defiance (挑战) against their parents. They figure out who they want to be, and music can play an important role in this process. A．Music is extremely personal.B．Most of them include music.C．Children like to listen to pop music.D．It exists in every corner of the globe.E．Music is critical in helping you learn a language.F．It affects them and brings them closer to others.G．Children attempt to imitate their parents for a long time.二、完形填空One early March morning in Baton Rouge, LA, a 11-year-old boy, Ellis, was waiting for his father outside a coffee house. He saw a middle-aged man walk in. A few moments 21 , he came out, stood in a corner and 22 his eyes.The boy took him for a/an 23 man. He had a dollar coin in his pocket, and realizing his chance to make a 24 had come, he walked right up to the man and said: “ 25 me, sir. Are you homeless? If you are, here’s a dollar.”The man opened his eyes and looked the boy, 26 . Thinking of his sleepless night, he 27 . Instead of accepting the coin, he 28 to buy Ellis a breakfast. Then they sat down to chat. With the 29 going, Ellis learned that the man he had 30 for homeless was Matthew Busbice, the co-founder of Wildgame Innovations. He has 31 three new hunting companies. His net 32 is an estimated $5 million.However, Busbice was touched that the kid was 33 to give everything he had to a stranger. If more kids like Ellis are going to 34 , they’re going to change the 35 , the state, and even the world.21．A．ago B．later C．away D．before 22．A．closed B．covered C．washed D．wiped 23．A．unemployed B．honest C．homeless D．funny 24．A．chance B．choice C．hero D．difference25．A．Pardon B．Excuse C．Believe D．Answer 26．A．pleased B．confused C．shocked D．excited 27．A．smiled B．feared C．recovered D．calmed 28．A．hoped B．requested C．offered D．decided 29．A．conversation B．breakfast C．friendship D．excitement 30．A．recognized B．pretended C．accepted D．mistaken 31．A．bought B．abandoned C．launched D．donated 32．A．worth B．result C．sum D．pay 33．A．capable B．willing C．reliable D．grateful 34．A．guide B．behave C．study D．give 35．A．history B．human C．community D．relation三、语法填空阅读下面短文，在空白处填入1个单词或括号内单词的正确形式。

弗里德里希·哈伯兰德教授——欧洲大豆业的先驱

■No.5.2018人物One can hardly overestimate the impact of FriedrichHaberlandt on the introduction of soybeans in Europe.His life is an archetype of an influential multinational academic in the Austrian-Hungarian Empire of the 19th century.After first finding out about the soybean in 1873,he was the first to conduct systematic trials with soybeans in Europe.He distributed his knowledgeto experts and users in many countries.In his vision of the potential of soybeans for European farmers and for feeding the growing population,he predicted develop⁃ments,which took place many generations after his early death.Although seemingly unsuccessful at first sight,his efforts formed a crucial starting point for the effective integration of soybeans in the Western Hemisphere.Friedrich Haberlandt was born on February 21stin 1826in Preßburg,now known as Bratislava,the capital of modern Slovakia (Shurtleff/Aoyagi 2008).Because his father,Gottlieb Haberlandt,was a craftsman in a German speaking community,he grew up in a tri-lingual environment learning Hungarian and Slovak languagesin his youth alongside German.He finished high school in his hometown where he also studied law for one year.He was a liberal and even volunteered in therevolution of 1848.He completed his studies in natural sciences at the establishment of higher education in Ungarisch-Altenburg (Mosonmagyaróvár in modernHungary)where he also started his academic career as an assistant professor.His thinking was highly influenced by the revolutionary works of scientists such as Justus von Liebig at that time.He lived in a time of fundamental technological and economic change.Rationalization processes and scientific knowledge were applied to many areas of society such as agriculture and diet (Kingsbury,中图分类号：S565.1文献标志码：E文章编号：1674-3547(2018)05-0001-02Friedrich Haberlandt-thePioneer of Soybean in EuropeGeorg Weissenböck 1,Dennis Böhmer 2,Leopold Rittler 3（1.Institute of Rural History,3109St.Pölten,Austria;2.University of Natural Resources and Life Sciences,Vienna.Institute for Plant Breeding,3430Tulln an der Donau,Austria;3.Donau Soja Organisation,1010Vienna,Austria）■No.5.2018人物2009).In 1853,Friedrich Haberlandt married Katharina Köhler.They had three daughters and three sons.His oldest son,Gottlieb Haberlandt (1854)became a famous botanist.Another son,Michael Haberlandt (1860)became an outstanding ethnologist and founded the museum for ethnology in Vienna in 1895.Friedrich Haberlandt was appointed professor for mathematics,zoology,botany and agricultural production in 1854.During the following period,he developed his distinct interest and sensitive talent for observation and an extensive activity in scientific networks (Haberlandt 1933).He left the college in 1869after the Austro-Hungarian Compromise.In Görz (Gorizia/Gorica inmodern Italy and Slovenia),he founded and led a research centre for silkworm breeding.When the first agricultural college in Austria,the Hochschule für Bodenkultur (the current University of Natural Resources and Life Sciences,Vienna)was founded 1872,Haberlandt was appointed outright professor,and later became rector of the university.He kept this position until his death in 1878.In the course of his research,he worked extensively on the soybeanas a protein supplier.【参考译文】弗里德里希·哈伯兰德教授——欧洲大豆业的先驱对于弗里德里希·哈伯兰德（Friedrich Haber⁃landt ）教授将大豆引进到欧洲所带来的巨大影响，无论给予多高的评价都不过分。

雅思英语artificial artists

雅思英语artificial artists雅思阅读Artificial artistsCan computers really create works of art?The Painting Fool is one of a growing number of computer programs which, so their makers claim, possess creative talents. Classical music by an artificial composer has had audiences enraptured, and even tricked them into believing a human was behind the score. Artworks painted by a robot have sold for thousands of dollars and been hung in prestigious galleries. And software has been built which creates art that could not have been imagined by the programmer.Human beings are the only species to perform sophisticated creative acts regularly. If we can break this process down into computer code, where does that leave human creativity? 'This is a question at the very core of humanity, ' says Geraint Wiggins, a computational creativity researcher at Goldsmiths, University of London. 'It scares a lot of people. They are worried that it is taking something special away from what it means to be human.'To some extent, we are all familiar with computerised art. The question is: where does the work of the artist stop and the creativity of the computer begin? Consider one of the oldest machine artists, Aaron, a robot that has had paintings exhibited in London's Tate Modern and the SanFrancisco Museum of Modern Art. Aaron can pick up a paintbrush and paint on canvas on its own. Impressive perhaps, but it is still little more than a tool to realise the programmer's own creative ideas.Simon Colton, the designer of the Painting Fool, is keen to make sure his creation doesn't attract the same criticism. Unlike earlier 'artists' such as Aaron, the Painting Fool only needs minimal direction and can come up with its own concepts by going online for material. The software runs its own web searches and trawls through social media sites. It is now beginning to display a kind of imagination too, creating pictures from scratch. One of its original works is a series of fuzzy landscapes, depicting trees and sky. While some might say they have a mechanical look, Colton argues that such reactions arise from people's double standards towards software-produced and human-produced art. After all, he says, consider that the Painting Fool painted the landscapes without referring to a photo. 'If a child painted a new scene from its head, you'd say it has a certain level of imagination, ' he points out. 'The same should be true of a machine.' Software bugs can also lead to unexpected results. Some of the Painting Fool's paintings of a chair came out in black and white, thanks to a technical glitch. This gives the work an eerie, ghostlike quality. Human artists like the renowned Ellsworth Kelly are lauded for limiting their colour palette - so why should computers be any different? Researchers like Colton don't believe it is right to measure machinecreativity directly to that of humans who 'have had millennia to develop our skills'. Others, though, are fascinated by the prospect that a computer might create something as original and subtle as our best artists. So far, only one has come close. Composer David Cope invented a program called Experiments in Musical Intelligence, or EMI. Not only did EMI create compositions in Cope's style, but also that of the most revered classical composers, including Bach, Chopin and Mozart. Audiences were moved to tears, and EMI even fooled classical music experts into thinking they were hearing genuine Bach. Not everyone was impressed however. Some, such as Wiggins, have blasted Cope's work as pseudoscience, and condemned him for his deliberately vague explanation of how the software worked. Meanwhile, Douglas Hofstadter of Indiana University said EMI created replicas which still rely completely on the original artist's creative impulses. When audiences found out the truth they were often outraged with Cope, and one music lover even tried to punch him. Amid such controversy, Cope destroyed EMI's vital databases.But why did so many people love the music, yet recoil when they discovered how it was composed? A study by computer scientist David Moffat of Glasgow Caledonian University provides a clue. He asked both expert musicians and non-experts to assess six compositions. The participants weren't told beforehand whether the tunes were composed by humans or computers, but were asked to guess, and then rate howmuch they liked each one. People who thought the composer was a computer tended to dislike the piece more than those who believed it was human. This was true even among the experts, who might have been expected to be more objective in their analyses.Where does this prejudice come from? Paul Bloom of Yale University has a suggestion: he reckons part of the pleasure we get from art stems from the creative process behind the work. This can give it an 'irresistible essence', says Bloom. Meanwhile, experiments by Justin Kruger of New York University have shown that people's enjoyment of an artwork increases if they think more time and effort was needed to create it. Similarly, Colton thinks that when people experience art, they wonder what the artist might have been thinking or what the artist is trying to tell them. It seems obvious, therefore, that with computers producing art, this speculation is cut short - there's nothing to explore. But as technology becomes increasingly complex, finding those greater depths in computer art could become possible. This is precisely why Colton asks the Painting Fool to tap into online social networks for its inspiration: hopefully this way it will choose themes that will already be meaningful to us.Questions 27-31Choose the correct letter, A, B, C or D.Write the correct letter in boxes 27-31 on your answer sheet.27 What is the writer suggesting about computer-produced works in the first paragraph?A People's acceptance of them can vary considerably.B A great deal of progress has already been attained in this field.C They have had more success in some artistic genres than in others.D The advances are not as significant as the public believes them to be.28 According to Geraint Wiggins, why are many people worried by computer art?A It is aesthetically inferior to human art.B It may ultimately supersede human art.C It undermines a fundamental human quality.D It will lead to a deterioration in human ability.29 What is a key difference between Aaron and the Painting Fool?A its programmer's backgroundB public response to its workC the source of its subject matterD the technical standard of its output30 What point does Simon Colton make in the fourth paragraph?A Software-produced art is often dismissed as childish and simplistic.B The same concepts of creativity should not be applied to all forms of art.C It is unreasonable to expect a machine to be as imaginative as a humanbeing.D People tend to judge computer art and human art according to different criteria.31 The writer refers to the paintings of a chair as an example of computer art whichA achieves a particularly striking effect.B exhibits a certain level of genuine artistic skill.C closely resembles that of a well-known artist.D highlights the technical limitations of the software.Questions 32-37Complete each sentence with the correct ending, A-G below.Write the correct letter, A-G, in boxes 32-37 on your answer sheet.32 Simon Colton says it is important to consider the long-term view when33 David Cope's EMI software surprised people by34 Geraint Wiggins criticised Cope for not35 Douglas Hofstadter claimed that EMI was36 Audiences who had listened to EMI's music became angry after37 The participants in David Moffat's study had to assess music without Questions 38-40Do the following statements agree with the claims of the writer in Reading Passage 3?In boxes 38-40 on your answer sheet, writeYES if the statement agrees with the claims of the writerNO if the statement contradicts the claims of the writerNOT GIVEN if it is impossible to say what the writer thinks about this38 Moffat's research may help explain people's reactions to EMI.39 The non-experts in Moffat's study all responded in a predictable way.40 Justin Kruger's findings cast doubt on Paul Bloom's theory about people's prejudice towards computer art.。

老鼠身上有细菌的英语作文

Rats,often maligned creatures in popular culture,are not only notorious for their ability to infest homes and carry diseases but also for their resilience and adaptability.The presence of bacteria on rats is a welldocumented fact,and it is this aspect that we will explore in this essay.Rats are known to carry a variety of bacteria that can pose a significant health risk to humans.One of the most common and potentially dangerous bacteria that rats can carry is Leptospira,which causes a disease known as leptospirosis.This bacterial infection can lead to severe symptoms such as high fever,headache,chills,muscle aches,and in severe cases,organ failure and even death.The bacteria are often found in rat urine,which can contaminate water sources and soil,posing a risk to anyone who comes into contact with these contaminated environments.Another bacteria that rats are known to harbor is Salmonella,a type of bacteria that can cause food poisoning.The presence of Salmonella on rats can contaminate food and surfaces,leading to illness in humans. Symptoms of Salmonella infection include diarrhea,fever,and abdominal cramps,which can be particularly dangerous for young children,the elderly,and those with weakened immune systems.In addition to these,rats can also carry the bacteria responsible for causing bubonic plague,Yersinia pestis.Historically,the plague has had devastating effects on human populations,with the most notable outbreak occurring in the14th century,which resulted in the deaths of an estimated 75to200million people in Eurasia and North Africa.While the risk of plague today is significantly lower due to advancements in medicine andpublic health,the potential for rats to carry this bacteria remains a concern.The ability of rats to carry bacteria is not limited to their physical contact with humans or the environment.Rats are also known to groom themselves,a process during which they can ingest their fur and the bacteria that reside there.This grooming behavior can lead to the internalization of bacteria,which can then be spread through their feces and urine.To mitigate the risk of bacterial transmission from rats,it is essential to implement effective rodent control measures.This includes sealing any entry points to buildings,maintaining cleanliness to reduce available food sources for rats,and using traps or poisons to control rat populations. Additionally,proper sanitation practices,such as washing hands thoroughly after handling potentially contaminated materials,can help prevent the spread of bacteria.Education about the risks associated with rats and the bacteria they carry is also crucial.Public awareness campaigns can inform people about the importance of maintaining a clean environment and the steps they can take to protect themselves from bacterial infections.In conclusion,while rats are often viewed as pests,their ability to carry and spread bacteria is a significant public health concern.By understanding the types of bacteria that rats can carry and the potential health risks they pose,we can take appropriate measures to protect ourselves and our communities.Through effective rodent control,sanitation practices,andpublic education,we can reduce the risk of bacterial transmission from rats and ensure a safer and healthier environment for all.。

卡特里娜

Such views baffle many people from outside the region, according to Eric Smith, Associate Director of Tulane University's Energy Institute.
"They think the fishermen and the oil and gas guys should be duking it out in the street, but they are not, because they are the same people," he said.
Waylon La Font and Mathew Cheramie are both residents of the Mississippi Delta who have worked on fishing boats as well as energy production.
They now fish on their own time because there is little work available, according to Cheramie.
Smith says the impact of the moratorium will worsen in the months ahead. He says rigs cost up to a million dollars a day, so oil companies cannot afford to leave them idle. He says eight drilling rigs that were on their way to the Gulf were diverted to other locations after the ban was imposed and two others have left since then.?

Measurement of the Branching Fractions and CP Asymmetries of B--D0(cp)K- Decays with the Ba

a r X i v :h e p -e x /0408082v 1 17 A u g 2004B A B A R -CONF-04/039SLAC-PUB-10655Measurement of the Branching Fractions and CP Asymmetries of B −→D 0(CP )K −Decays with the B A B A R Detector The B A B A R Collaboration February 7,2008Abstract We present a study of B −→D 0(CP )K −decays,where D 0(CP )is reconstructed in ﬂavor (K −π+),CP -even (K −K +,π−π+)and CP -odd (K 0S π0)eigenstates,based on a sample of about 214million Υ(4S )→BB (B −→D 0K −)/B (B −→D 0π−)=0.87±0.14(stat)±0.06(syst),R −≡B (B −→D 0CP −K −)/B (B −→D 0CP −π−)B (B −→D 0CP +K −)+B (B +→D 0CP +K +)=0.40±0.15(stat)±0.08(syst)B(B−→D0CP−K−)−B(B+→D0CP−K+)A CP−≡Work supported in part by Department of Energy contract DE-AC03-76SF00515.The B A B A R Collaboration,B.Aubert,R.Barate,D.Boutigny,F.Couderc,J.-M.Gaillard,A.Hicheur,Y.Karyotakis,J.P.Lees,V.Tisserand,A.ZghicheLaboratoire de Physique des Particules,F-74941Annecy-le-Vieux,FranceA.Palano,A.PompiliUniversit`a di Bari,Dipartimento di Fisica and INFN,I-70126Bari,ItalyJ.C.Chen,N.D.Qi,G.Rong,P.Wang,Y.S.ZhuInstitute of High Energy Physics,Beijing100039,ChinaG.Eigen,I.Ofte,B.StuguUniversity of Bergen,Inst.of Physics,N-5007Bergen,NorwayG.S.Abrams,A.W.Borgland,A.B.Breon,D.N.Brown,J.Button-Shafer,R.N.Cahn,E.Charles, C.T.Day,M.S.Gill,A.V.Gritsan,Y.Groysman,R.G.Jacobsen,R.W.Kadel,J.Kadyk,L.T.Kerth,Yu.G.Kolomensky,G.Kukartsev,G.Lynch,L.M.Mir,P.J.Oddone,T.J.Orimoto,M.Pripstein,N.A.Roe,M.T.Ronan,V.G.Shelkov,W.A.WenzelLawrence Berkeley National Laboratory and University of California,Berkeley,CA94720,USAM.Barrett,K.E.Ford,T.J.Harrison,A.J.Hart,C.M.Hawkes,S.E.Morgan,A.T.Watson University of Birmingham,Birmingham,B152TT,United KingdomM.Fritsch,K.Goetzen,T.Held,H.Koch,B.Lewandowski,M.Pelizaeus,M.SteinkeRuhr Universit¨a t Bochum,Institut f¨u r Experimentalphysik1,D-44780Bochum,GermanyJ.T.Boyd,N.Chevalier,W.N.Cottingham,M.P.Kelly,tham,F.F.WilsonUniversity of Bristol,Bristol BS81TL,United KingdomT.Cuhadar-Donszelmann,C.Hearty,N.S.Knecht,T.S.Mattison,J.A.McKenna,D.Thiessen University of British Columbia,Vancouver,BC,Canada V6T1Z1A.Khan,P.Kyberd,L.TeodorescuBrunel University,Uxbridge,Middlesex UB83PH,United KingdomA.E.Blinov,V.E.Blinov,V.P.Druzhinin,V.B.Golubev,V.N.Ivanchenko,E.A.Kravchenko,A.P.Onuchin,S.I.Serednyakov,Yu.I.Skovpen,E.P.Solodov,A.N.YushkovBudker Institute of Nuclear Physics,Novosibirsk630090,RussiaD.Best,M.Bruinsma,M.Chao,I.Eschrich,D.Kirkby,nkford,M.Mandelkern,R.K.Mommsen,W.Roethel,D.P.StokerUniversity of California at Irvine,Irvine,CA92697,USAC.Buchanan,B.L.HartﬁelUniversity of California at Los Angeles,Los Angeles,CA90024,USAS.D.Foulkes,J.W.Gary,B.C.Shen,K.WangUniversity of California at Riverside,Riverside,CA92521,USAD.del Re,H.K.Hadavand,E.J.Hill,D.B.MacFarlane,H.P.Paar,Sh.Rahatlou,V.SharmaUniversity of California at San Diego,La Jolla,CA92093,USAJ.W.Berryhill,C.Campagnari,B.Dahmes,O.Long,A.Lu,M.A.Mazur,J.D.Richman,W.Verkerke University of California at Santa Barbara,Santa Barbara,CA93106,USAT.W.Beck,A.M.Eisner,C.A.Heusch,J.Kroseberg,W.S.Lockman,G.Nesom,T.Schalk,B.A.Schumm,A.Seiden,P.Spradlin,D.C.Williams,M.G.WilsonUniversity of California at Santa Cruz,Institute for Particle Physics,Santa Cruz,CA95064,USAJ.Albert,E.Chen,G.P.Dubois-Felsmann,A.Dvoretskii,D.G.Hitlin,I.Narsky,T.Piatenko,F.C.Porter,A.Ryd,A.Samuel,S.YangCalifornia Institute of Technology,Pasadena,CA91125,USAS.Jayatilleke,G.Mancinelli,B.T.Meadows,M.D.SokoloﬀUniversity of Cincinnati,Cincinnati,OH45221,USAT.Abe,F.Blanc,P.Bloom,S.Chen,W.T.Ford,U.Nauenberg,A.Olivas,P.Rankin,J.G.Smith,J.Zhang,L.ZhangUniversity of Colorado,Boulder,CO80309,USAA.Chen,J.L.Harton,A.Soﬀer,W.H.Toki,R.J.Wilson,Q.ZengColorado State University,Fort Collins,CO80523,USAD.Altenburg,T.Brandt,J.Brose,M.Dickopp,E.Feltresi,A.Hauke,cker,R.M¨u ller-Pfeﬀerkorn, R.Nogowski,S.Otto,A.Petzold,J.Schubert,K.R.Schubert,R.Schwierz,B.Spaan,J.E.Sundermann Technische Universit¨a t Dresden,Institut f¨u r Kern-und Teilchenphysik,D-01062Dresden,GermanyD.Bernard,G.R.Bonneaud,F.Brochard,P.Grenier,S.Schrenk,Ch.Thiebaux,G.Vasileiadis,M.VerderiEcole Polytechnique,LLR,F-91128Palaiseau,FranceD.J.Bard,P.J.Clark,vin,F.Muheim,S.Playfer,Y.XieUniversity of Edinburgh,Edinburgh EH93JZ,United KingdomM.Andreotti,V.Azzolini,D.Bettoni,C.Bozzi,R.Calabrese,G.Cibinetto,E.Luppi,M.Negrini,L.Piemontese,A.SartiUniversit`a di Ferrara,Dipartimento di Fisica and INFN,I-44100Ferrara,ItalyE.TreadwellFlorida A&M University,Tallahassee,FL32307,USAF.Anulli,R.Baldini-Ferroli,A.Calcaterra,R.de Sangro,G.Finocchiaro,P.Patteri,I.M.Peruzzi,M.Piccolo,A.ZalloLaboratori Nazionali di Frascati dell’INFN,I-00044Frascati,ItalyA.Buzzo,R.Capra,R.Contri,G.Crosetti,M.Lo Vetere,M.Macri,M.R.Monge,S.Passaggio,C.Patrignani,E.Robutti,A.Santroni,S.TosiUniversit`a di Genova,Dipartimento di Fisica and INFN,I-16146Genova,ItalyS.Bailey,G.Brandenburg,K.S.Chaisanguanthum,M.Morii,E.WonHarvard University,Cambridge,MA02138,USAR.S.Dubitzky,ngeneggerUniversit¨a t Heidelberg,Physikalisches Institut,Philosophenweg12,D-69120Heidelberg,Germany W.Bhimji,D.A.Bowerman,P.D.Dauncey,U.Egede,J.R.Gaillard,G.W.Morton,J.A.Nash,M.B.Nikolich,G.P.TaylorImperial College London,London,SW72AZ,United KingdomM.J.Charles,G.J.Grenier,U.MallikUniversity of Iowa,Iowa City,IA52242,USAJ.Cochran,H.B.Crawley,msa,W.T.Meyer,S.Prell,E.I.Rosenberg,A.E.Rubin,J.YiIowa State University,Ames,IA50011-3160,USAM.Biasini,R.Covarelli,M.PioppiUniversit`a di Perugia,Dipartimento di Fisica and INFN,I-06100Perugia,ItalyM.Davier,X.Giroux,G.Grosdidier,A.H¨o cker,place,F.Le Diberder,V.Lepeltier,A.M.Lutz, T.C.Petersen,S.Plaszczynski,M.H.Schune,L.Tantot,G.WormserLaboratoire de l’Acc´e l´e rateur Lin´e aire,F-91898Orsay,FranceC.H.Cheng,nge,M.C.Simani,D.M.WrightLawrence Livermore National Laboratory,Livermore,CA94550,USAA.J.Bevan,C.A.Chavez,J.P.Coleman,I.J.Forster,J.R.Fry,E.Gabathuler,R.Gamet,D.E.Hutchcroft,R.J.Parry,D.J.Payne,R.J.Sloane,C.TouramanisUniversity of Liverpool,Liverpool L6972E,United KingdomJ.J.Back,1C.M.Cormack,P.F.Harrison,1F.Di Lodovico,G.B.Mohanty1Queen Mary,University of London,E14NS,United KingdomC.L.Brown,G.Cowan,R.L.Flack,H.U.Flaecher,M.G.Green,P.S.Jackson,T.R.McMahon,S.Ricciardi,F.Salvatore,M.A.WinterUniversity of London,Royal Holloway and Bedford New College,Egham,Surrey TW200EX,United KingdomD.Brown,C.L.DavisUniversity of Louisville,Louisville,KY40292,USAJ.Allison,N.R.Barlow,R.J.Barlow,P.A.Hart,M.C.Hodgkinson,ﬀerty,A.J.Lyon,J.C.WilliamsUniversity of Manchester,Manchester M139PL,United KingdomA.Farbin,W.D.Hulsbergen,A.Jawahery,D.Kovalskyi,e,V.Lillard,D.A.RobertsUniversity of Maryland,College Park,MD20742,USAG.Blaylock,C.Dallapiccola,K.T.Flood,S.S.Hertzbach,R.Koﬂer,V.B.Koptchev,T.B.Moore,S.Saremi,H.Staengle,S.WillocqUniversity of Massachusetts,Amherst,MA01003,USAR.Cowan,G.Sciolla,S.J.Sekula,F.Taylor,R.K.Yamamoto Massachusetts Institute of Technology,Laboratory for Nuclear Science,Cambridge,MA02139,USAD.J.J.Mangeol,P.M.Patel,S.H.RobertsonMcGill University,Montr´e al,QC,Canada H3A2T8zzaro,V.Lombardo,F.PalomboUniversit`a di Milano,Dipartimento di Fisica and INFN,I-20133Milano,ItalyJ.M.Bauer,L.Cremaldi,V.Eschenburg,R.Godang,R.Kroeger,J.Reidy,D.A.Sanders,D.J.Summers,H.W.ZhaoUniversity of Mississippi,University,MS38677,USAS.Brunet,D.Cˆo t´e,P.TarasUniversit´e de Montr´e al,Laboratoire Ren´e J.A.L´e vesque,Montr´e al,QC,Canada H3C3J7H.NicholsonMount Holyoke College,South Hadley,MA01075,USAN.Cavallo,2F.Fabozzi,2C.Gatto,L.Lista,D.Monorchio,P.Paolucci,D.Piccolo,C.Sciacca Universit`a di Napoli Federico II,Dipartimento di Scienze Fisiche and INFN,I-80126,Napoli,ItalyM.Baak,H.Bulten,G.Raven,H.L.Snoek,L.WildenNIKHEF,National Institute for Nuclear Physics and High Energy Physics,NL-1009DB Amsterdam,The NetherlandsC.P.Jessop,J.M.LoSeccoUniversity of Notre Dame,Notre Dame,IN46556,USAT.Allmendinger,K.K.Gan,K.Honscheid,D.Hufnagel,H.Kagan,R.Kass,T.Pulliam,A.M.Rahimi,R.Ter-Antonyan,Q.K.WongOhio State University,Columbus,OH43210,USAJ.Brau,R.Frey,O.Igonkina,C.T.Potter,N.B.Sinev,D.Strom,E.TorrenceUniversity of Oregon,Eugene,OR97403,USAF.Colecchia,A.Dorigo,F.Galeazzi,M.Margoni,M.Morandin,M.Posocco,M.Rotondo,F.Simonetto,R.Stroili,G.Tiozzo,C.VociUniversit`a di Padova,Dipartimento di Fisica and INFN,I-35131Padova,ItalyM.Benayoun,H.Briand,J.Chauveau,P.David,Ch.de la Vaissi`e re,L.Del Buono,O.Hamon,M.J.J.John,Ph.Leruste,J.Malcles,J.Ocariz,M.Pivk,L.Roos,S.T’Jampens,G.Therin Universit´e s Paris VI et VII,Laboratoire de Physique Nucl´e aire et de Hautes Energies,F-75252Paris,FranceP.F.Manfredi,V.ReUniversit`a di Pavia,Dipartimento di Elettronica and INFN,I-27100Pavia,ItalyP.K.Behera,L.Gladney,Q.H.Guo,J.PanettaUniversity of Pennsylvania,Philadelphia,PA19104,USAC.Angelini,G.Batignani,S.Bettarini,M.Bondioli,F.Bucci,G.Calderini,M.Carpinelli,F.Forti, M.A.Giorgi,A.Lusiani,G.Marchiori,F.Martinez-Vidal,3M.Morganti,N.Neri,E.Paoloni,M.Rama,G.Rizzo,F.Sandrelli,J.WalshUniversit`a di Pisa,Dipartimento di Fisica,Scuola Normale Superiore and INFN,I-56127Pisa,ItalyM.Haire,D.Judd,K.Paick,D.E.WagonerPrairie View A&M University,Prairie View,TX77446,USAN.Danielson,P.Elmer,u,C.Lu,V.Miftakov,J.Olsen,A.J.S.Smith,A.V.TelnovPrinceton University,Princeton,NJ08544,USAF.Bellini,G.Cavoto,4R.Faccini,F.Ferrarotto,F.Ferroni,M.Gaspero,L.Li Gioi,M.A.Mazzoni,S.Morganti,M.Pierini,G.Piredda,F.Safai Tehrani,C.VoenaUniversit`a di Roma La Sapienza,Dipartimento di Fisica and INFN,I-00185Roma,ItalyS.Christ,G.Wagner,R.WaldiUniversit¨a t Rostock,D-18051Rostock,GermanyT.Adye,N.De Groot,B.Franek,N.I.Geddes,G.P.Gopal,E.O.Olaiya Rutherford Appleton Laboratory,Chilton,Didcot,Oxon,OX110QX,United KingdomR.Aleksan,S.Emery,A.Gaidot,S.F.Ganzhur,P.-F.Giraud,G.Hamel de Monchenault,W.Kozanecki, M.Legendre,G.W.London,B.Mayer,G.Schott,G.Vasseur,Ch.Y`e che,M.ZitoDSM/Dapnia,CEA/Saclay,F-91191Gif-sur-Yvette,FranceM.V.Purohit,A.W.Weidemann,J.R.Wilson,F.X.YumicevaUniversity of South Carolina,Columbia,SC29208,USAD.Aston,R.Bartoldus,N.Berger,A.M.Boyarski,O.L.Buchmueller,R.Claus,M.R.Convery,M.Cristinziani,G.De Nardo,D.Dong,J.Dorfan,D.Dujmic,W.Dunwoodie,E.E.Elsen,S.Fan, R.C.Field,T.Glanzman,S.J.Gowdy,T.Hadig,V.Halyo,C.Hast,T.Hryn’ova,W.R.Innes, M.H.Kelsey,P.Kim,M.L.Kocian,D.W.G.S.Leith,J.Libby,S.Luitz,V.Luth,H.L.Lynch,H.Marsiske,R.Messner,D.R.Muller,C.P.O’Grady,V.E.Ozcan,A.Perazzo,M.Perl,S.Petrak, B.N.Ratcliﬀ,A.Roodman,A.A.Salnikov,R.H.Schindler,J.Schwiening,G.Simi,A.Snyder,A.Soha,J.Stelzer,D.Su,M.K.Sullivan,J.Va’vra,S.R.Wagner,M.Weaver,A.J.R.Weinstein, W.J.Wisniewski,M.Wittgen,D.H.Wright,A.K.Yarritu,C.C.YoungStanford Linear Accelerator Center,Stanford,CA94309,USAP.R.Burchat,A.J.Edwards,T.I.Meyer,B.A.Petersen,C.RoatStanford University,Stanford,CA94305-4060,USAS.Ahmed,M.S.Alam,J.A.Ernst,M.A.Saeed,M.Saleem,F.R.WapplerState University of New York,Albany,NY12222,USAW.Bugg,M.Krishnamurthy,S.M.SpanierUniversity of Tennessee,Knoxville,TN37996,USAR.Eckmann,H.Kim,J.L.Ritchie,A.Satpathy,R.F.SchwittersUniversity of Texas at Austin,Austin,TX78712,USAJ.M.Izen,I.Kitayama,X.C.Lou,S.YeUniversity of Texas at Dallas,Richardson,TX75083,USAF.Bianchi,M.Bona,F.Gallo,D.GambaUniversit`a di Torino,Dipartimento di Fisica Sperimentale and INFN,I-10125Torino,ItalyL.Bosisio,C.Cartaro,F.Cossutti,G.Della Ricca,S.Dittongo,S.Grancagnolo,nceri,P.Poropat,5L.Vitale,G.VuagninUniversit`a di Trieste,Dipartimento di Fisica and INFN,I-34127Trieste,ItalyR.S.PanviniVanderbilt University,Nashville,TN37235,USASw.Banerjee,C.M.Brown,D.Fortin,P.D.Jackson,R.Kowalewski,J.M.Roney,R.J.SobieUniversity of Victoria,Victoria,BC,Canada V8W3P6H.R.Band,B.Cheng,S.Dasu,M.Datta,A.M.Eichenbaum,M.Graham,J.J.Hollar,J.R.Johnson,P.E.Kutter,H.Li,R.Liu,A.Mihalyi,A.K.Mohapatra,Y.Pan,R.Prepost,P.Tan,J.H.vonWimmersperg-Toeller,J.Wu,S.L.Wu,Z.YuUniversity of Wisconsin,Madison,WI53706,USAM.G.Greene,H.NealYale University,New Haven,CT06511,USA1INTRODUCTIONA theoretically clean measurement of the angleγ=arg(−V ud V∗ub/V cd V∗cb)can be obtained from the study of B−→D(∗)0K(∗)−decays by exploiting the interference between the b→c¯u s and b→u¯c s decay amplitudes[1].The method originally proposed by Gronau,Wyler and London is based on the interference between B−→D0K−and B−→D0decay to CP eigenstates.We deﬁne the ratios R and R CP±of Cabibbo-suppressed to Cabibbo-favored branching fractionsR(CP±)≡B(B−→D0(CP±)K−)+B(B+→B(B−→D0(CP±)π−)+B(B+→B(B−→D0CP±K−)+B(B+→D0CP±K+).(2)Neglecting the D0−D0π−)/A(B−→D0π−)of the amplitudes of the B−→D0K−)/A(B−→D0K−)|is the magnitude of the ratio of the amplitudes for the processes B−→B pairs collected with the B A B A R detector at the PEP-II asymmetric-energy B factory.The B A B A R detector is described in detail elsewhere[2].Charged-particle tracking is provided by aﬁve-layer silicon vertex tracker(SVT)and a40-layer drift chamber(DCH).For charged-particle identiﬁcation,ionization energy loss in the DCH and SVT,and Cherenkov radia-tion detected in a ring-imaging device(DIRC)are used.Photons are identiﬁed by the electromag-netic calorimeter(EMC),which comprises6580thallium-doped CsI crystals.These systems are mounted inside a1.5-T solenoidal superconducting magnet.The segmentedﬂux return,including endcaps,is instrumented with resistive plate chambers(IFR)for muon and K0Lidentiﬁcation.We use the GEANT[3]software to simulate interactions of particles traversing the detector,taking into account the varying accelerator and detector conditions.3ANALYSIS METHODWe reconstruct B−→D0h−decays,where the prompt track h−is a kaon or a pion.Reference to the charge-conjugate state is implied here and throughout the text unless otherwise stated.Candidates for D0are reconstructed in the CP-even eigenstatesπ−π+and K−K+,in the CP-odd eigenstate K0Sπ0,and in the non-CPﬂavor eigenstate K−π+.K0Scandidates are selected in theπ−π+channel.The prompt particle h−is required to have momentum greater than1.4GeV/c.Particle IDinformation from the drift chamber and,when available,from the DIRC must be consistent with the kaon hypothesis for the K meson candidate in all D0modes and with the pion hypothesis for theπ±meson candidates in the D0→π−π+mode.For the prompt track to be identiﬁed as a pion or a kaon,we require that at leastﬁve Cherenkov photons are detected to insure a good measurement of the Cherenkov angle.We reject a candidate track if its Cherenkov angle is not within3σof the expected value for either the kaon or pion mass hypothesis.We also reject candidate tracks that are identiﬁed as electrons by the DCH and the EMC or as muons by the DCH and the IFR.Photon candidates are clusters in the EMC that are not matched to any charged track,have a raw energy greater than30MeV and lateral shower shape consistent with the expected pattern of energy deposit from an electromagnetic shower.Photon pairs with invariant mass within the range 115–150MeV/c2(∼3σ)and total energy greater than200MeV are consideredπ0candidates. To improve the momentum resolution,theπ0candidates are kinematicallyﬁt with their mass constrained to the nominalπ0mass[4].Neutral kaons are reconstructed from pairs of oppositely charged tracks with the invariant mass within10MeV(∼3σ)from the nominal K0mass.We also require that the ratio between theﬂight length distance in the plane transverse to the beams direction and its uncertainty is greater than 3.The invariant mass of a D0candidate,m(D0),must be within3σof the D0mass.The D0mass resolutionσis about7.5MeV in the K−π+,K−K+andπ−π+modes,and about21MeV in the π0mode.Selected D0candidates areﬁtted with a constraint to the nominal D0mass.K0SWe reconstruct B meson candidates by combining a D0candidate with a track h−.For the K−π+mode,the charge of the track h−must match that of the kaon from the D0me-son decay.We select B meson candidates by using the beam-energy-substituted mass m ES=rejects more than90%of the continuum background while retaining77%of the signal in the K−π+, K−K+and K0π0modes and65%in theπ−π+channel.SMultiple B−→D0h−candidates are found in about4%of the events for the K0Sπ0and in less than1%of the events for the other D0decays.In these events aχ2is constructed from m(π0)(for K0Sπ0only),m(D0),and m ES and only the candidate with the smallestχ2is retained.The total reconstruction eﬃciencies,based on simulated signal events,are about33%(K−π+),28%(K−K+), 26%(π−π+)and17%(K0Sπ0).The main contributions to the BB events,in which the prompt track is either a pion or a kaon.The input variables to theﬁt are∆E and a particle identiﬁcation probability for the prompt track based on the Cherenkov angleθC,the momentum p and the polar angleθof the track.The extended likelihood function L is deﬁned asL=exp −M i=1n i N j=1 M i=1n i P i(∆E,θC; αi) ,(3)where N is the total number of observed events.The M functions P i(∆E,θC; αi)are the probability density functions(PDFs)for the variables∆E,θC,given the set of parameters αi.Since these two quantities are suﬃciently uncorrelated,their probability density functions are evaluated as a product P i=P i(∆E; αi)×P i(θC; αi).The∆E distribution for B−→D0K−signal events is parametrized with a Gaussian function. The∆E distribution for B−→D0π−is parametrized with the same Gaussian used for B−→D0K−with a relative shift of the mean,computed event by event as a function of the prompt track momentum,arising from the wrong mass assignment to the prompt track.The oﬀset and width of the Gaussian are keptﬂoating in theﬁt and are determined from data together with the yields.The∆E distribution for the continuum background is parametrized with a linear function whose slope is determined from oﬀ-resonance data.The∆E distribution for the B4PHYSICS RESULTS AND SYSTEMATIC STUDIESThe results of theﬁt are summarized in Table1.Figure1shows the distributions of∆E for the K−π+,CP+and CP−modes after enhancing the B→D0K purity by requiring that the prompt track be consistent with the kaon hypothesis.This requirement is about95%eﬃcient for the B−→D0K−signal while retaining only4%of the B−→D0π−candidates.The projection of a likelihoodﬁt,modiﬁed to take into account the tighter selection criteria,is overlaid in theﬁgure. Table1:Results of the B−→D0K−and B−→D0π−yields from the maximum-likelihoodﬁt on data.D0mode N(B→D0π)N(B→D0K)N(B−→D0K−)N(B+→K−π+11930±120897±34441±24456±25K0Sπ01248±4076+13−1246+10−930+9−8The double ratios R±are computed by scaling the ratios of the numbers of B−→D0K−and B−→D0π−mesons by correction factors(ranging from0.997to1.020depending on the D0mode) that account for small diﬀerences in the eﬃciency between the B−→D0K−and B−→D0π−selec-tions,estimated with simulated signal samples.The results are listed in Table2.The direct CP asymmetries A CP±for the B±→D0CP±K±decays are calculated from the measured yields of positive and negative charged meson decays and the results are reported in Table2.Table2:Measured double branching fraction ratios R±and CP asymmetries A CP±for diﬀerent D0decay modes.Theﬁrst error is statistical,the second is systematic.D0decay mode R CP/R A CPK−K+0.92±0.16±0.070.43±0.16±0.09π−π+0.70±0.29±0.090.27±0.40±0.09CP-even combined0.87±0.14±0.060.40±0.15±0.08The uncertainties in the branching fractions of the channels contributing to the B[6]Belle Collaboration,K.Abe et al.,Phys.Rev.D6*******(2002);B A B A R Collaboration,B.Aubert et al.,hep-ex/0308065,submitted to Phys.Rev.Lett..[7]B A B A R Collaboration,B.Aubert et al.,Phys.Rev.Lett.92202002(2004).Figure1:∆E distributions of B−→D0h−candidates,where a charged kaon mass hypothesis is assumed for h.Events are enhanced in B−→D0K−purity by requiring the Cherenkov angle of the track h to be within2σof the kaon hypothesis.Top:B−→D0[K−π+]K−;middle:B−→π0]K−.Solid curves represent projections of D0CP+[K−K+,π−π+]K−;bottom:B−→D0CP−[K0Sthe maximum likelihoodﬁt;dashed-dotted,dotted and dashed curves represent the B→D0K,B→D0πand background contributions.。

关于北印度洋海峡的英文阅读理解

关于北印度洋海峡的英文阅读理解The Bay of Bengal is connected to the Arabian Sea by the Strait of Malacca, an important waterway separating the Indonesian island of Sumatra from Malaysia. The Strait of Malacca is one of the busiest shipping lanes in the world, facilitating most of the trade between Europe, the Middle East, and Asia. It is a significant source of income for Malaysia and Indonesia.The Strait of Malacca is located between the Andaman and Nicobar Islands on the east and the Malay Peninsula on the west. It is approximately 805 km long and at its narrowest point, it is only 1.5 nautical miles wide. The strait is susceptible to piracy due to its narrow width and heavy traffic, which makes it a challenge for ships to navigate safely.Many countries rely on the Strait of Malacca for theiroil imports and exports. It is a vital passage for oil transportation, connecting the oil-rich Middle East with countries like China, Japan, and South Korea. Any disruption in the strait due to piracy or natural disasters like earthquakes or tsunamis can have a significant impact on global oil prices and trade.To ensure the safety of vessels passing through theStrait of Malacca, Malaysia, Singapore, and Indonesia have set up the Malacca Strait Patrol (MSP) in collaboration with other countries like Thailand and the Philippines. The MSP conducts regular patrols to deter piracy and ensure the security of the strait. Additionally, a Traffic Separation Scheme (TSS) has been implemented to regulate the movement of vessels and reduce the risk of collisions.The importance of the Strait of Malacca as a trade route cannot be overstated. It is estimated that around one-thirdof global trade passes through this waterway, including oil, gas, and other commodities. Countries like Singapore have established themselves as major shipping hubs due to their strategic location along the strait.Now, let's see some examples of bilingual sentences:1. The Strait of Malacca plays a crucial role in facilitating international trade.马六甲海峡在促进国际贸易方面起着至关重要的作用。

rFSA包用户指南说明书

Package‘rFSA’October14,2022Type PackageTitle Feasible Solution Algorithm for Finding Best Subsets andInteractionsVersion0.9.6Date2020-06-10DescriptionAssists in statistical model building toﬁnd optimal and semi-optimal higher order interactions and best es the lm(),glm(),and other R functions toﬁt models generated from a feasible solution algorithm.Discussed in Subset Selection in Regression,A Miller(2002).Ap-plied and explainedfor least median of squares in Hawkins(1993)<doi:10.1016/0167-9473(93)90246-P>.The feasible solutionalgorithm comes up with model forms of a speciﬁc type that can haveﬁxed variables,higher order interactions and their lower order terms.License GPL-2LazyData TRUEImports parallel,methods,tibble,rPref,tidyr,hashRoxygenNote7.1.0NeedsCompilation noAuthor Joshua Lambert[aut,cre],Liyu Gong[aut],Corrine Elliott[aut],Sarah Janse[ctb]Maintainer Joshua Lambert<*********************>Repository CRANDate/Publication2020-06-1020:20:03UTCR topics documented:adj.r.squared (2)apress (3)12adj.r.squaredbdist (3)ﬁtmodels (4)ﬁtted.FSA (4)FSA (5)int.p.val (7)list.criterion (7)max_abs_resid (8)nextswap (8)pFSA (9)plot.FSA (11)predict.FSA (11)print.FSA (12)QICu.geeglm (13)r.squared (13)rmse (13)summary.FSA (14)swaps (14)twFSA (15)which.max.na (16)which.min.na (17)Index18 adj.r.squared An rFSA Criterion Function.DescriptionrFSA Criterion Function to compute Adjusted R-Squared.Usageadj.r.squared(model,name="Adj R Squared")Argumentsmodel lm or glmﬁt to be passed.name passed to print.FSAapress3 apress An rFSA Criterion Function.DescriptionrFSA Criterion Function to Allen’s Press Statistic.Usageapress(model,name="PRESS")Argumentsmodel lm or glmﬁt to be passed.name passed to print.FSAbdist An rFSA Criterion Function.DescriptionrFSA Criterion Function to compute the Bhattacharyya distance.Usagebdist(model,name="B Distance")Argumentsmodel lm or glmﬁt to be passed.name passed to print.FSAExamples#To use Bhattacharyya Distance and FSA the response must be binary,and you must#be considering searching for two way continuous interactions.data(mtcars)fit<-FSA(formula="am~gear*hp",data=mtcars,fitfunc=glm,family="binomial",m=2,cores=1,interactions=TRUE,criterion=bdist,minmax="max")4ﬁtted.FSA fitmodels Modelﬁtting function for FSA solutionsDescriptionModelﬁtting function for FSA solutionsUsagefitmodels(object,...)Argumentsobject FSA object to construct models on....other parameters passed to lm or glm.See help(lm)or help(glm)for other po-tential arguements.Valuelist of FSA models that have beenﬁtted.Examples#use mtcars package see help(mtcars)data(mtcars)colnames(mtcars)fit<-lmFSA(formula="mpg~hp*wt",data=mtcars,fixvar="hp",quad=FALSE,m=2,numrs=10,save_solutions=FALSE,cores=1)fitmodels(fit)fitted.FSA Fitted Values for FSA solutionsDescriptionFitted Values for FSA solutionsUsage##S3method for class FSAfitted(object,...)Argumentsobject FSA object to getﬁtted values from....other parameters passed toﬁtmodels orﬁtted function.See help(ﬁtmodels)or help(ﬁtted)for assistance.FSA5Valuelist ofﬁtted values from each FSA model.Examples#use mtcars package see help(mtcars)data(mtcars)colnames(mtcars)fit<-lmFSA(formula="mpg~hp*wt",data=mtcars,fixvar="hp",quad=FALSE,m=2,numrs=10,save_solutions=FALSE,cores=1)fitted(fit)FSA FSA:Feasible Solution AlgorithmDescriptionA function using a Feasible Solution Algorithm toﬁnd a set of feasible solutions for a statisticalmodel of a speciﬁc form that could include mth-order interactions(Note that these solutions are optimal in the sense that no one swap to any of the variables will increase the criterion function.)UsageFSA(formula,data,fitfunc=lm,fixvar=NULL,quad=FALSE,m=2,numrs=1,cores=1,interactions=T,criterion=AIC,minmax="min",checkfeas=NULL,var4int=NULL,min.nonmissing=1,return.models=FALSE,fix.formula=NULL,...)lmFSA(...)glmFSA(...)6FSAArgumentsformula an object of class"formula"(or one that can be coerced to that class):a symbolic description of the model to beﬁtted.data a data frame,list or environment(or object coercible by as.data.frame to a data frame)containing the variables in the model.fitfunc the method that should be used toﬁt the model.For Example:lm,glm,or other methods that rely on formula,data,and other inputs.fixvar variable(s)toﬁx in the ually a covariate that should always be in-cluded(Example:Age,Sex).Will still consider it with interactions.Default isNULL.quad Include quadratic terms or not.Logical.m order of terms to include.If interactions is set to TRUE then m is the order of interactions to be considered.For Subset selection(interaction=F),m is the sizeof the subset to examine.Defaults to2.numrs number of random starts to perform.cores number of cores to use while running.Note:Windows can only use1core.See mclapply for details.If function detects a Windows user it will automatically setcores=1.interactions whether to include interactions in model.Defaults to TRUE.criterion which criterion function to either maximize or minimize.For linear models one can use:r.squared,adj.r.squared,cv5.lmFSA(5Fold Cross Validation error),cv10.lmFSA(10Fold Cross Validation error),apress(Allen’s Press Statistic),int.p.val(Interaction P-value),AIC,BIC.minmax whether to minimize or maximize the criterion functioncheckfeas vector of variables that could be a feasible solution.These variables will be used as the last random start.var4int speciﬁcation of which variables to check for marginal feasiblilty.Default is NULLmin.nonmissing the combination of predictors will be ignored unless this many of observations are not missingreturn.models bool value to specify whether return all theﬁtted models which have been checkedfix.formula......other arguments passed toﬁtfunc.Valuematrix of resultsFunctions•FSA:ﬁnd best set of variables for statistical models•lmFSA:alias for FSA(fitfunc=lm,...)•glmFSA:alias for FSA(fitfunc=glm,...)int.p.val7 ExamplesN<-10#number of obsP<-100#number of variablesdata<-data.frame(matrix(rnorm(N*(P+1)),nrow=N,ncol=P+1))sln<-FSA(formula="X101~1",data=data,cores=1,m=2,interactions=FALSE,criterion=AIC,minmax="min",numrs=10)slnint.p.val An rFSA Criterion Function.DescriptionrFSA Criterion Function to compute Liklihood Ratio Test Statistics p-value for the largest order interation term.Usageint.p.val(model,name="Interaction P-Value")Argumentsmodel lm or glmﬁt to be passed.name passed to print.FSAlist.criterion List all included Criteria function for lmFSA and glmFSA.DescriptionList all included Criteria function for lmFSA and glmFSA.Usagelist.criterion()Valuelist of functions and whether lmFSA or glmFSA work with those functions.Exampleslist.criterion()8nextswap max_abs_resid Return maximum absolute residual from a modelDescriptionReturn maximum absolute residual from a modelUsagemax_abs_resid(model)Argumentsmodel model objnextswap Variables to include in the>1st step of an mth order interaction modeldetermined from the Feasible Soution Alorithm.DescriptionFinds the swaps available given a current position given previous picks.Usagenextswap(curpos,n,prevpos,quad)Argumentscurpos A vector of length greater than2of what current explantory varialbes are being used in the model.n The number of explanatory variables in available to swap.prevpos A vector of previous best spotsquad Whether to include quadratic terms.ie(x1*x1)as potential swaps.Valuea matrix with the possible forms by column.pFSA9 pFSA pFSA:Pareto Feasible Solution AlgorithmDescriptionA function using a Feasible Solution Algorithm to estimate a set of models which are on the Paretofrontiers for chosen criteriaUsagepFSA(numFronts=2,pselExpr=NULL,plot.it=TRUE,formula,data,fitfunc=lm,fixvar=NULL,quad=FALSE,m=2,numrs=1,cores=1,interactions=T,criterion=AIC,minmax="min",checkfeas=NULL,var4int=NULL,min.nonmissing=1,return.models=FALSE,fix.formula=NULL,...)ArgumentsnumFronts integer number of estimated frontiers to returnpselExpr expression used by function psel to estimate pareto frontiers.help(psel).plot.it TRUE/FALSE for whether to plot the pareto frontiersformula an object of class"formula"(or one that can be coerced to that class):a symbolic description of the model to beﬁtted.data a data frame,list or environment(or object coercible by as.data.frame to a data frame)containing the variables in the model.fitfunc the method that should be used toﬁt the model.For Example:lm,glm,or other methods that rely on formula,data,and other inputs.10pFSAfixvar variable(s)toﬁx in the ually a covariate that should always be in-cluded(Example:Age,Sex).Will still consider it with interactions.Default isNULL.quad Include quadratic terms or not.Logical.m order of terms to include.If interactions is set to TRUE then m is the order of interactions to be considered.For Subset selection(interaction=F),m is the sizeof the subset to examine.Defaults to2.numrs number of random starts to perform.cores number of cores to use while running.Note:Windows can only use1core.See mclapply for details.If function detects a Windows user it will automatically setcores=1.interactions whether to include interactions in model.Defaults to TRUE.criterion which criterion function to either maximize or minimize.For linear models one can use:r.squared,adj.r.squared,cv5.lmFSA(5Fold Cross Validation error),cv10.lmFSA(10Fold Cross Validation error),apress(Allen’s Press Statistic),int.p.val(Interaction P-value),AIC,BIC.minmax whether to minimize or maximize the criterion functioncheckfeas vector of variables that could be a feasible solution.These variables will be used as the last random start.var4int speciﬁcation of which variables to check for marginal feasiblilty.Default is NULLmin.nonmissing the combination of predictors will be ignored unless this many of observations are not missingreturn.models bool value to specify whether return all theﬁtted models which have been checkedfix.formula......see arguments taken by function FSA or other functions.help(FSA).Valuelist of a matrix of all models obtained from FSA(ﬁts)and their criteria.Also a matrix of the estimated frontiers that were requested.The Key column inﬁts,and pbound refers to the column number of the variables contined in the modelﬁt.For instance,Key="42,96"would refer to the model which contains the variable in the42nd column and96th column of the designated dataset.ExamplesN<-1000#number of obsP<-100#number of variablesdata<-data.frame(matrix(rnorm(N*(P+1)),nrow=N,ncol=P+1))sln<-pFSA(formula="X101~1",data=data,m=2,criterion=c(max_abs_resid,r.squared), minmax=c("min","max"),numrs=10,numFronts=2,pselExpr=rPref::low(max_abs_resid)*rPref::high(r.squared),plot.it=TRUE)plot.FSA11 plot.FSA Diagnostic Plots for FSA solutionsDescriptionDiagnostic Plots for FSA solutionsUsage##S3method for class FSAplot(x,ask=F,easy=T,...)Argumentsx FSA object to see diagnostic plots on.ask logical;if TRUE,the user is asked before each plot.See help(plot.lm).easy logical;should diagnostic plots be presented in easy to read format?...arguments to be passed to other functions.Valuediagnostic plots to plot window.Examples#use mtcars package see help(mtcars)data(mtcars)colnames(mtcars)fit<-lmFSA(formula="mpg~hp*wt",data=mtcars,fixvar="hp",quad=FALSE,m=2,numrs=10,save_solutions=FALSE,cores=1)plot(x=fit)predict.FSA Prediction function for FSA solutionsDescriptionPrediction function for FSA solutionsUsage##S3method for class FSApredict(object,...)12print.FSAArgumentsobject FSA object to conduct predictions on....other parameters passed toﬁtmodels or predict functions.See help(ﬁtmodels) or help(predict)for assistance.Valuelist of predicted values from each FSA model.Examples#use mtcars package see help(mtcars)data(mtcars)colnames(mtcars)fit<-lmFSA(formula="mpg~hp*wt",data=mtcars,fixvar="hp",quad=FALSE,m=2,numrs=10,save_solutions=FALSE,cores=1)predict(fit)predict(fit,newdata=mtcars[1:15,])print.FSA Printing function for FSA solutionsDescriptionPrinting function for FSA solutionsUsage##S3method for class FSAprint(x,...)Argumentsx FSA object to print details about....arguments to be passed to other functions.Valuelist of Feasible Solution Formula’s,Original Fitted model formula and criterion function and times converged to details.Examples#use mtcars package see help(mtcars)data(mtcars)colnames(mtcars)fit<-lmFSA(formula="mpg~hp*wt",data=mtcars,fixvar="hp",quad=FALSE,m=2,numrs=10,save_solutions=FALSE,cores=1) print(fit)QICu.geeglm13 QICu.geeglm Return QICu for geepack::geeglmDescriptionComputes quasi-likelihood under the independence criterion(QICu)UsageQICu.geeglm(gee.obj)Argumentsgee.obj geeglm objr.squared An rFSA Criterion Function.DescriptionrFSA Criterion Function to compute R squared.Usager.squared(model,name="R Squared")Argumentsmodel lm or glmﬁt to be passed.name passed to print.FSArmse An rFSA Criterion Function.DescriptionrFSA Criterion Function to compute Root Mean Squared Error.Usagermse(model,name="RMSE")Argumentsmodel lm or glmﬁt to be passed.name passed to print.FSA14swaps summary.FSA Summary function for FSA solutionsDescriptionSummary function for FSA solutionsUsage##S3method for class FSAsummary(object,...)Argumentsobject FSA object to see summaries on....arguments to be passed to other functions.Valuelist of summarized lm or glm output.Examples#use mtcars package see help(mtcars)data(mtcars)colnames(mtcars)fit<-lmFSA(formula="mpg~hp*wt",data=mtcars,fixvar="hp",quad=FALSE,m=2,numrs=10,save_solutions=FALSE,cores=1)summary(fit)swaps Variables to include inﬁrst steip of an mth order interaction modeldetermined from the Feasible Soution Alorithm.DescriptionFinds the swaps available given a current position.Usageswaps(cur,n,quad=FALSE,yindex)twFSA15Argumentscur A vector of length greater than2of what current explantory varialbes are being used in the model.n The number of explanatory variables in available to swap.quad Whether to include quadratic terms.ie(x1*x1)as potential swaps.yindex index of response variable.Valuea matrix with the possible forms by column.twFSA twFSADescriptionA function for termwise feasiblityUsagetwFSA(formula,data,fitfunc=lm,fixvar=NULL,quad=FALSE,cores=1,criterion=AIC,minmax="min",checkfeas=NULL,var4int=NULL,min.nonmissing=1,...)Argumentsformula an object of class"formula"(or one that can be coerced to that class):a symbolic description of the model to beﬁtted.data a data frame,list or environment(or object coercible by as.data.frame to a data frame)containing the variables in the model.fitfunc the method that should be used toﬁt the model.For Example:lm,glm,or other methods that rely on formula,data,and other inputs.fixvar variable(s)toﬁx in the ually a covariate that should always be in-cluded(Example:Age,Sex).Will still consider it with interactions.Default isNULL.16which.max.naquad Include quadratic terms or not.Logical.cores number of cores to use while running.Note:Windows can only use1core.See mclapply for details.If function detects a Windows user it will automatically setcores=1.criterion which criterion function to either maximize or minimize.For linear models one can use:r.squared,adj.r.squared,cv5.lmFSA(5Fold Cross Validation error),cv10.lmFSA(10Fold Cross Validation error),apress(Allen’s Press Statistic),int.p.val(Interaction P-value),AIC,BIC.minmax whether to minimize or maximize the criterion functioncheckfeas vector of variables that could be a feasible solution.These variables will be used as the last random start.var4int speciﬁcation of which variables to check for marginal feasiblilty.Default is NULLmin.nonmissing the combination of predictors will be ignored unless this many of observations are not missing...other arguments passed toﬁtfunc.Valuematrix of resultswhich.max.na An rFSA Internal Function.DescriptionrFSA function to compute the maximum value from a vector with NA’s.Usagewhich.max.na(vec)Argumentsvec Vector to be passed.which.min.na17 which.min.na An rFSA Internal Function.DescriptionrFSA function to compute the minimum value from a vector with NA’s.Usagewhich.min.na(vec)Argumentsvec Vector to be passed.Indexadj.r.squared,2apress,3bdist,3fitmodels,4fitted.FSA,4FSA,5glmFSA(FSA),5int.p.val,7list.criterion,7lmFSA(FSA),5max_abs_resid,8nextswap,8pFSA,9plot.FSA,11predict.FSA,11print.FSA,12QICu.geeglm,13r.squared,13rmse,13summary.FSA,14swaps,14twFSA,15which.max.na,16which.min.na,1718。

专八英语阅读

英语专业八级考试TEM-8阅读理解练习册（1）(英语专业2012级)UNIT 1Text AEvery minute of every day, what ecologist生态学家James Carlton calls a global ―conveyor belt‖, redistributes ocean organisms生物.It’s planetwide biological disruption生物的破坏that scientists have barely begun to understand.Dr. Carlton —an oceanographer at Williams College in Williamstown,Mass.—explains that, at any given moment, ―There are several thousand marine species traveling… in the ballast water of ships.‖ These creatures move from coastal waters where they fit into the local web of life to places where some of them could tear that web apart. This is the larger dimension of the infamous无耻的，邪恶的invasion of fish-destroying, pipe-clogging zebra mussels有斑马纹的贻贝.Such voracious贪婪的invaders at least make their presence known. What concerns Carlton and his fellow marine ecologists is the lack of knowledge about the hundreds of alien invaders that quietly enter coastal waters around the world every day. Many of them probably just die out. Some benignly亲切地，仁慈地—or even beneficially — join the local scene. But some will make trouble.In one sense, this is an old story. Organisms have ridden ships for centuries. They have clung to hulls and come along with cargo. What’s new is the scale and speed of the migrations made possible by the massive volume of ship-ballast water压载水— taken in to provide ship stability—continuously moving around the world…Ships load up with ballast water and its inhabitants in coastal waters of one port and dump the ballast in another port that may be thousands of kilometers away. A single load can run to hundreds of gallons. Some larger ships take on as much as 40 million gallons. The creatures that come along tend to be in their larva free-floating stage. When discharged排出in alien waters they can mature into crabs, jellyfish水母, slugs鼻涕虫，蛞蝓, and many other forms.Since the problem involves coastal species, simply banning ballast dumps in coastal waters would, in theory, solve it. Coastal organisms in ballast water that is flushed into midocean would not survive. Such a ban has worked for North American Inland Waterway. But it would be hard to enforce it worldwide. Heating ballast water or straining it should also halt the species spread. But before any such worldwide regulations were imposed, scientists would need a clearer view of what is going on.The continuous shuffling洗牌of marine organisms has changed the biology of the sea on a global scale. It can have devastating effects as in the case of the American comb jellyfish that recently invaded the Black Sea. It has destroyed that sea’s anchovy鳀鱼fishery by eating anchovy eggs. It may soon spread to western and northern European waters.The maritime nations that created the biological ―conveyor belt‖ should support a coordinated international effort to find out what is going on and what should be done about it. (456 words)1.According to Dr. Carlton, ocean organism‟s are_______.A.being moved to new environmentsB.destroying the planetC.succumbing to the zebra musselD.developing alien characteristics2.Oceanographers海洋学家are concerned because_________.A.their knowledge of this phenomenon is limitedB.they believe the oceans are dyingC.they fear an invasion from outer-spaceD.they have identified thousands of alien webs3.According to marine ecologists, transplanted marinespecies____________.A.may upset the ecosystems of coastal watersB.are all compatible with one anotherC.can only survive in their home watersD.sometimes disrupt shipping lanes4.The identified cause of the problem is_______.A.the rapidity with which larvae matureB. a common practice of the shipping industryC. a centuries old speciesD.the world wide movement of ocean currents5.The article suggests that a solution to the problem__________.A.is unlikely to be identifiedB.must precede further researchC.is hypothetically假设地，假想地easyD.will limit global shippingText BNew …Endangered‟ List Targets Many US RiversIt is hard to think of a major natural resource or pollution issue in North America today that does not affect rivers.Farm chemical runoff残渣, industrial waste, urban storm sewers, sewage treatment, mining, logging, grazing放牧,military bases, residential and business development, hydropower水力发电,loss of wetlands. The list goes on.Legislation like the Clean Water Act and Wild and Scenic Rivers Act have provided some protection, but threats continue.The Environmental Protection Agency (EPA) reported yesterday that an assessment of 642,000 miles of rivers and streams showed 34 percent in less than good condition. In a major study of the Clean Water Act, the Natural Resources Defense Council last fall reported that poison runoff impairs损害more than 125,000 miles of rivers.More recently, the NRDC and Izaak Walton League warned that pollution and loss of wetlands—made worse by last year’s flooding—is degrading恶化the Mississippi River ecosystem.On Tuesday, the conservation group保护组织American Rivers issued its annual list of 10 ―endangered‖ and 20 ―threatened‖ rivers in 32 states, the District of Colombia, and Canada.At the top of the list is the Clarks Fork of the Yellowstone River, whereCanadian mining firms plan to build a 74-acre英亩reservoir水库，蓄水池as part of a gold mine less than three miles from Yellowstone National Park. The reservoir would hold the runoff from the sulfuric acid 硫酸used to extract gold from crushed rock.―In the event this tailings pond failed, the impact to th e greater Yellowstone ecosystem would be cataclysmic大变动的，灾难性的and the damage irreversible不可逆转的.‖ Sen. Max Baucus of Montana, chairman of the Environment and Public Works Committee, wrote to Noranda Minerals Inc., an owner of the ― New World Mine‖.Last fall, an EPA official expressed concern about the mine and its potential impact, especially the plastic-lined storage reservoir. ― I am unaware of any studies evaluating how a tailings pond尾矿池，残渣池could be maintained to ensure its structural integrity forev er,‖ said Stephen Hoffman, chief of the EPA’s Mining Waste Section. ―It is my opinion that underwater disposal of tailings at New World may present a potentially significant threat to human health and the environment.‖The results of an environmental-impact statement, now being drafted by the Forest Service and Montana Department of State Lands, could determine the mine’s future…In its recent proposal to reauthorize the Clean Water Act, the Clinton administration noted ―dramatically improved water quality since 1972,‖ when the act was passed. But it also reported that 30 percent of riverscontinue to be degraded, mainly by silt泥沙and nutrients from farm and urban runoff, combined sewer overflows, and municipal sewage城市污水. Bottom sediments沉积物are contaminated污染in more than 1,000 waterways, the administration reported in releasing its proposal in January. Between 60 and 80 percent of riparian corridors (riverbank lands) have been degraded.As with endangered species and their habitats in forests and deserts, the complexity of ecosystems is seen in rivers and the effects of development----beyond the obvious threats of industrial pollution, municipal waste, and in-stream diversions改道to slake消除the thirst of new communities in dry regions like the Southwes t…While there are many political hurdles障碍ahead, reauthorization of the Clean Water Act this year holds promise for US rivers. Rep. Norm Mineta of California, who chairs the House Committee overseeing the bill, calls it ―probably the most important env ironmental legislation this Congress will enact.‖ (553 words)6.According to the passage, the Clean Water Act______.A.has been ineffectiveB.will definitely be renewedC.has never been evaluatedD.was enacted some 30 years ago7.“Endangered” rivers are _________.A.catalogued annuallyB.less polluted than ―threatened rivers‖C.caused by floodingD.adjacent to large cities8.The “cataclysmic” event referred to in paragraph eight would be__________.A. fortuitous偶然的，意外的B. adventitious外加的，偶然的C. catastrophicD. precarious不稳定的，危险的9. The owners of the New World Mine appear to be______.A. ecologically aware of the impact of miningB. determined to construct a safe tailings pondC. indifferent to the concerns voiced by the EPAD. willing to relocate operations10. The passage conveys the impression that_______.A. Canadians are disinterested in natural resourcesB. private and public environmental groups aboundC. river banks are erodingD. the majority of US rivers are in poor conditionText CA classic series of experiments to determine the effects ofoverpopulation on communities of rats was reported in February of 1962 in an article in Scientific American. The experiments were conducted by a psychologist, John B. Calhoun and his associates. In each of these experiments, an equal number of male and female adult rats were placed in an enclosure and given an adequate supply of food, water, and other necessities. The rat populations were allowed to increase. Calhoun knew from experience approximately how many rats could live in the enclosures without experiencing stress due to overcrowding. He allowed the population to increase to approximately twice this number. Then he stabilized the population by removing offspring that were not dependent on their mothers. He and his associates then carefully observed and recorded behavior in these overpopulated communities. At the end of their experiments, Calhoun and his associates were able to conclude that overcrowding causes a breakdown in the normal social relationships among rats, a kind of social disease. The rats in the experiments did not follow the same patterns of behavior as rats would in a community without overcrowding.The females in the rat population were the most seriously affected by the high population density: They showed deviant异常的maternal behavior; they did not behave as mother rats normally do. In fact, many of the pups幼兽，幼崽, as rat babies are called, died as a result of poor maternal care. For example, mothers sometimes abandoned their pups,and, without their mothers' care, the pups died. Under normal conditions, a mother rat would not leave her pups alone to die. However, the experiments verified that in overpopulated communities, mother rats do not behave normally. Their behavior may be considered pathologically 病理上，病理学地diseased.The dominant males in the rat population were the least affected by overpopulation. Each of these strong males claimed an area of the enclosure as his own. Therefore, these individuals did not experience the overcrowding in the same way as the other rats did. The fact that the dominant males had adequate space in which to live may explain why they were not as seriously affected by overpopulation as the other rats. However, dominant males did behave pathologically at times. Their antisocial behavior consisted of attacks on weaker male,female, and immature rats. This deviant behavior showed that even though the dominant males had enough living space, they too were affected by the general overcrowding in the enclosure.Non-dominant males in the experimental rat communities also exhibited deviant social behavior. Some withdrew completely; they moved very little and ate and drank at times when the other rats were sleeping in order to avoid contact with them. Other non-dominant males were hyperactive; they were much more active than is normal, chasing other rats and fighting each other. This segment of the rat population, likeall the other parts, was affected by the overpopulation.The behavior of the non-dominant males and of the other components of the rat population has parallels in human behavior. People in densely populated areas exhibit deviant behavior similar to that of the rats in Calhoun's experiments. In large urban areas such as New York City, London, Mexican City, and Cairo, there are abandoned children. There are cruel, powerful individuals, both men and women. There are also people who withdraw and people who become hyperactive. The quantity of other forms of social pathology such as murder, rape, and robbery also frequently occur in densely populated human communities. Is the principal cause of these disorders overpopulation? Calhoun’s experiments suggest that it might be. In any case, social scientists and city planners have been influenced by the results of this series of experiments.11. Paragraph l is organized according to__________.A. reasonsB. descriptionC. examplesD. definition12．Calhoun stabilized the rat population_________.A. when it was double the number that could live in the enclosure without stressB. by removing young ratsC. at a constant number of adult rats in the enclosureD. all of the above are correct13.W hich of the following inferences CANNOT be made from theinformation inPara. 1?A. Calhoun's experiment is still considered important today.B. Overpopulation causes pathological behavior in rat populations.C. Stress does not occur in rat communities unless there is overcrowding.D. Calhoun had experimented with rats before.14. Which of the following behavior didn‟t happen in this experiment?A. All the male rats exhibited pathological behavior.B. Mother rats abandoned their pups.C. Female rats showed deviant maternal behavior.D. Mother rats left their rat babies alone.15. The main idea of the paragraph three is that __________.A. dominant males had adequate living spaceB. dominant males were not as seriously affected by overcrowding as the otherratsC. dominant males attacked weaker ratsD. the strongest males are always able to adapt to bad conditionsText DThe first mention of slavery in the statutes法令，法规of the English colonies of North America does not occur until after 1660—some forty years after the importation of the first Black people. Lest we think that existed in fact before it did in law, Oscar and Mary Handlin assure us, that the status of B lack people down to the 1660’s was that of servants. A critique批判of the Handlins’ interpretation of why legal slavery did not appear until the 1660’s suggests that assumptions about the relation between slavery and racial prejudice should be reexamined, and that explanation for the different treatment of Black slaves in North and South America should be expanded.The Handlins explain the appearance of legal slavery by arguing that, during the 1660’s, the position of white servants was improving relative to that of black servants. Thus, the Handlins contend, Black and White servants, heretofore treated alike, each attained a different status. There are, however, important objections to this argument. First, the Handlins cannot adequately demonstrate that t he White servant’s position was improving, during and after the 1660’s; several acts of the Maryland and Virginia legislatures indicate otherwise. Another flaw in the Handlins’ interpretation is their assumption that prior to the establishment of legal slavery there was no discrimination against Black people. It is true that before the 1660’s Black people were rarely called slaves. But this shouldnot overshadow evidence from the 1630’s on that points to racial discrimination without using the term slavery. Such discrimination sometimes stopped short of lifetime servitude or inherited status—the two attributes of true slavery—yet in other cases it included both. The Handlins’ argument excludes the real possibility that Black people in the English colonies were never treated as the equals of White people.The possibility has important ramifications后果，影响.If from the outset Black people were discriminated against, then legal slavery should be viewed as a reflection and an extension of racial prejudice rather than, as many historians including the Handlins have argued, the cause of prejudice. In addition, the existence of discrimination before the advent of legal slavery offers a further explanation for the harsher treatment of Black slaves in North than in South America. Freyre and Tannenbaum have rightly argued that the lack of certain traditions in North America—such as a Roman conception of slavery and a Roman Catholic emphasis on equality— explains why the treatment of Black slaves was more severe there than in the Spanish and Portuguese colonies of South America. But this cannot be the whole explanation since it is merely negative, based only on a lack of something. A more compelling令人信服的explanation is that the early and sometimes extreme racial discrimination in the English colonies helped determine the particular nature of the slavery that followed. (462 words)16. Which of the following is the most logical inference to be drawn from the passage about the effects of “several acts of the Maryland and Virginia legislatures” (Para.2) passed during and after the 1660‟s?A. The acts negatively affected the pre-1660’s position of Black as wellas of White servants.B. The acts had the effect of impairing rather than improving theposition of White servants relative to what it had been before the 1660’s.C. The acts had a different effect on the position of white servants thandid many of the acts passed during this time by the legislatures of other colonies.D. The acts, at the very least, caused the position of White servants toremain no better than it had been before the 1660’s.17. With which of the following statements regarding the status ofBlack people in the English colonies of North America before the 1660‟s would the author be LEAST likely to agree?A. Although black people were not legally considered to be slaves,they were often called slaves.B. Although subject to some discrimination, black people had a higherlegal status than they did after the 1660’s.C. Although sometimes subject to lifetime servitude, black peoplewere not legally considered to be slaves.D. Although often not treated the same as White people, black people,like many white people, possessed the legal status of servants.18. According to the passage, the Handlins have argued which of thefollowing about the relationship between racial prejudice and the institution of legal slavery in the English colonies of North America?A. Racial prejudice and the institution of slavery arose simultaneously.B. Racial prejudice most often the form of the imposition of inheritedstatus, one of the attributes of slavery.C. The source of racial prejudice was the institution of slavery.D. Because of the influence of the Roman Catholic Church, racialprejudice sometimes did not result in slavery.19. The passage suggests that the existence of a Roman conception ofslavery in Spanish and Portuguese colonies had the effect of _________.A. extending rather than causing racial prejudice in these coloniesB. hastening the legalization of slavery in these colonies.C. mitigating some of the conditions of slavery for black people in these coloniesD. delaying the introduction of slavery into the English colonies20. The author considers the explanation put forward by Freyre andTannenbaum for the treatment accorded B lack slaves in the English colonies of North America to be _____________.A. ambitious but misguidedB. valid有根据的but limitedC. popular but suspectD. anachronistic过时的，时代错误的and controversialUNIT 2Text AThe sea lay like an unbroken mirror all around the pine-girt, lonely shores of Orr’s Island. Tall, kingly spruce s wore their regal王室的crowns of cones high in air, sparkling with diamonds of clear exuded gum流出的树胶; vast old hemlocks铁杉of primeval原始的growth stood darkling in their forest shadows, their branches hung with long hoary moss久远的青苔;while feathery larches羽毛般的落叶松,turned to brilliant gold by autumn frosts, lighted up the darker shadows of the evergreens. It was one of those hazy朦胧的, calm, dissolving days of Indian summer, when everything is so quiet that the fainest kiss of the wave on the beach can be heard, and white clouds seem to faint into the blue of the sky, and soft swathing一长条bands of violet vapor make all earth look dreamy, and give to the sharp, clear-cut outlines of the northern landscape all those mysteries of light and shade which impart such tenderness to Italian scenery.The funeral was over,--- the tread鞋底的花纹/ 踏of many feet, bearing the heavy burden of two broken lives, had been to the lonely graveyard, and had come back again,--- each footstep lighter and more unconstrained不受拘束的as each one went his way from the great old tragedy of Death to the common cheerful of Life.The solemn black clock stood swaying with its eternal ―tick-tock, tick-tock,‖ in the kitchen of the brown house on Orr’s Island. There was there that sense of a stillness that can be felt,---such as settles down on a dwelling住处when any of its inmates have passed through its doors for the last time, to go whence they shall not return. The best room was shut up and darkened, with only so much light as could fall through a little heart-shaped hole in the window-shutter,---for except on solemn visits, or prayer-meetings or weddings, or funerals, that room formed no part of the daily family scenery.The kitchen was clean and ample, hearth灶台, and oven on one side, and rows of old-fashioned splint-bottomed chairs against the wall. A table scoured to snowy whiteness, and a little work-stand whereon lay the Bible, the Missionary Herald, and the Weekly Christian Mirror, before named, formed the principal furniture. One feature, however, must not be forgotten, ---a great sea-chest水手用的储物箱,which had been the companion of Zephaniah through all the countries of the earth. Old, and battered破旧的，磨损的, and unsightly难看的it looked, yet report said that there was good store within which men for the most part respect more than anything else; and, indeed it proved often when a deed of grace was to be done--- when a woman was suddenly made a widow in a coast gale大风，狂风, or a fishing-smack小渔船was run down in the fogs off the banks, leaving in some neighboring cottage a family of orphans,---in all such cases, the opening of this sea-chest was an event of good omen 预兆to the bereaved丧亲者;for Zephaniah had a large heart and a large hand, and was apt有…的倾向to take it out full of silver dollars when once it went in. So the ark of the covenant约柜could not have been looked on with more reverence崇敬than the neighbours usually showed to Captain Pennel’s sea-chest.1. The author describes Orr‟s Island in a(n)______way.A.emotionally appealing, imaginativeB.rational, logically preciseC.factually detailed, objectiveD.vague, uncertain2.According to the passage, the “best room”_____.A.has its many windows boarded upB.has had the furniture removedC.is used only on formal and ceremonious occasionsD.is the busiest room in the house3.From the description of the kitchen we can infer that thehouse belongs to people who_____.A.never have guestsB.like modern appliancesC.are probably religiousD.dislike housework4.The passage implies that_______.A.few people attended the funeralB.fishing is a secure vocationC.the island is densely populatedD.the house belonged to the deceased5.From the description of Zephaniah we can see thathe_________.A.was physically a very big manB.preferred the lonely life of a sailorC.always stayed at homeD.was frugal and saved a lotText BBasic to any understanding of Canada in the 20 years after the Second World War is the country' s impressive population growth. For every three Canadians in 1945, there were over five in 1966. In September 1966 Canada's population passed the 20 million mark. Most of this surging growth came from natural increase. The depression of the 1930s and the war had held back marriages, and the catching-up process began after 1945. The baby boom continued through the decade of the 1950s, producing a population increase of nearly fifteen percent in the five years from 1951 to 1956. This rate of increase had been exceeded only once before in Canada's history, in the decade before 1911 when the prairies were being settled. Undoubtedly, the good economic conditions of the 1950s supported a growth in the population, but the expansion also derived from a trend toward earlier marriages and an increase in the average size of families; In 1957 the Canadian birth rate stood at 28 per thousand, one of the highest in the world. After the peak year of 1957, thebirth rate in Canada began to decline. It continued falling until in 1966 it stood at the lowest level in 25 years. Partly this decline reflected the low level of births during the depression and the war, but it was also caused by changes in Canadian society. Young people were staying at school longer, more women were working; young married couples were buying automobiles or houses before starting families; rising living standards were cutting down the size of families. It appeared that Canada was once more falling in step with the trend toward smaller families that had occurred all through theWestern world since the time of the Industrial Revolution. Although the growth in Canada’s population had slowed down by 1966 (the cent), another increase in the first half of the 1960s was only nine percent), another large population wave was coming over the horizon. It would be composed of the children of the children who were born during the period of the high birth rate prior to 1957.6. What does the passage mainly discuss?A. Educational changes in Canadian society.B. Canada during the Second World War.C. Population trends in postwar Canada.D. Standards of living in Canada.7. According to the passage, when did Canada's baby boom begin?A. In the decade after 1911.B. After 1945.C. During the depression of the 1930s.D. In 1966.8. The author suggests that in Canada during the 1950s____________.A. the urban population decreased rapidlyB. fewer people marriedC. economic conditions were poorD. the birth rate was very high9. When was the birth rate in Canada at its lowest postwar level?A. 1966.B. 1957.C. 1956.D. 1951.10. The author mentions all of the following as causes of declines inpopulation growth after 1957 EXCEPT_________________.A. people being better educatedB. people getting married earlierC. better standards of livingD. couples buying houses11.I t can be inferred from the passage that before the IndustrialRevolution_______________.A. families were largerB. population statistics were unreliableC. the population grew steadilyD. economic conditions were badText CI was just a boy when my father brought me to Harlem for the first time, almost 50 years ago. We stayed at the hotel Theresa, a grand brick structure at 125th Street and Seventh avenue. Once, in the hotel restaurant, my father pointed out Joe Louis. He even got Mr. Brown, the hotel manager, to introduce me to him, a bit punchy强力的but still champ焦急as fast as I was concerned.Much has changed since then. Business and real estate are booming. Some say a new renaissance is under way. Others decry责难what they see as outside forces running roughshod肆意践踏over the old Harlem. New York meant Harlem to me, and as a young man I visited it whenever I could. But many of my old haunts are gone. The Theresa shut down in 1966. National chains that once ignored Harlem now anticipate yuppie money and want pieces of this prime Manhattan real estate. So here I am on a hot August afternoon, sitting in a Starbucks that two years ago opened a block away from the Theresa, snatching抓取，攫取at memories between sips of high-priced coffee. I am about to open up a piece of the old Harlem---the New York Amsterdam News---when a tourist。

新视野大学英语(第三版)读写教程Book2-unit8-textA课文翻译

Unit 8 Section A Animals or children?—A scientist's choice动物还是孩子？——一位科学家的选择1 I am the enemy! I am one of those cursed, cruel physician scientists involved in animal research. These rumors sting, for I have never thought of myself as an evil person. I became a children's doctor because of my love for children and my supreme desire to keep them healthy. During medical school and residency, I saw many children die of cancer and bloodshed from injury —circumstances against which medicine has made great progress but still has a long way to go. More importantly, I also saw children healthy thanks to advances in medical science such as infant breathing support, powerful new medicines and surgical techniques and the entire field of organ transplantation. My desire to tip the scales in favor of healthy, happy children drew me to medical research.1 我就是那个敌人！我就是那些被人诅咒的、残忍的、搞动物实验的医生科学家之一。

专业年级

西南政法大学试卷（A 卷）2006 — 2007 学年第二学期课程大学英语专业全校各专业平行班年级 2005级本试卷共 10 页，满分 100 分；考试时间：120 分钟；考试方式：闭卷注意事项1、本学期使用新机读卡，主观题与客观题的答案都填写在一张卡上，卡上准考证号一栏填学生完整的学号，请正确填写自己的学号，学号请按示范填写，填错或不填阅卷系统记录为零分。

示范如下：学号为2005111101，填涂为：2、3、选择题按对应编号，用铅笔将答案划在机读卡上。

主观题的答案写在机读卡上指定栏内，在指定栏以外地方作答将记录为零分。

4、主观题作答时请一定在卡上写清楚每题对应的大编号与小编号。

5、注意保持机读卡面清洁、无折叠、无污损，否则阅卷系统不能正常识别。

Part I Listening Comprehension (25%) Section ADirections: In this section, you’ll hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will be spoken ONLY ONCE . Listen carefully and choose the best answer to each question.1. A) The man refuses to listen to his doctor ’s advice. B) The man is under pressure from his wife. C) The man usually follows his wife ’s advice. D) The man no longer smokes.2. A) In a department store. B) In a bank. C) At a hotel. D) At a tourist bureau.3. A) Manager and clerk.B) College advisor and student. C) Architect and computer expert.D) Architect and mathematics department head. 4. A) The woman has been complaining too much.------------------------------------------------------------------------------------------------------------------------------------------------------------------ -密-----------------封-----------------线-------------------内-------------------不---------------------要-----------------------答-------------------题------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ 学生姓名：___________________ 学号：_________________ 专业年级：_________________ 考试教室：____________B) The woman’s headache will go away by itself.C) The woman should have seen the doctor earlier.D) The woman should confirm her appointment with the doctor.5. A) She did poorly on the exam.B) She complained about the man making the highest mark.C) She often makes careless mistakes.D) She wanted the highest grade but got only the second highest.6. A) He may need to take an extra course.B) The degree will take a shorter time in the future.C) Degrees will be easier to finish next year.D) There is no regulation of the courses next year.7. A) At last he enjoys campus life.B) School has changed little since last year.C) He has many new friends.D) It’s easier to find his way around this year.8. A) He’s afraid to try some of the exercises himself.B) The physics class is only halfway over.C) The students aren’t in good physical condition.D) He doesn’t believe everything people say.Questions 9-12 are based on the conversation you have just heard.9. A) To choose a topic for a term paper.B) To get material not available at the main library.C) To type some research materials.D) To learn to use the computers there.10. A) A comparison of political journals and newspapers.B) The impact of TV on recent presidential election.C) The use of computers in calculating election results.D) An analysis of early presidential results.11. A) It is quite general.B) It should be changed.C) It’ll take a short time to find the relevant materials.D) It is closely related with information in a newspaper.12. A) He pays a little money to use it.B) He orders it from the publisher.C) He travels to that library to get it.D) He reads it in the graduate school library.Questions 13-15 are based on the conversation you have just heard.13. A) Abroad. B) To the seaside.C) To his mother. D) To the mountains.14. A) His wife. B) His mother. C) A friend. D) A nurse.15. A) Joining him and his wife for the holiday.B) Sending her sister’s children to their grandmother.C) Going to the mountains.D) Going for a tour abroad.Section BDirections: In this section, you’ll hear 3 short passages. At the end of each passage, you will hear some questions. Both the passage and the questions will be spoken ONLY ONCE.Passage OneQuestions 16-18 are based on the conversation you have just heard.16. A) She feels that they must offer more if they wish to attract students.B) She feels that they should cut back on graduate programs.C) She feels that they still maintain their usual sacred position in the eyes of the general public.D) She feels that they should not concern themselves with the needs of prospective students.17. A) She believes that students are more emotionally mature than they once were.B) She believes that students consider all colleges inferior.C) She believes that students realize that a college education is no longer important.D) She believes that students are aware of the fact that a college degree does not necessarily guaranteelong term job success.18. A) All private institutions will close down.B) Private institutions must meet society’s needs in some specified fields.C) Private institutions have to satisfy their customers.D) Private institutions have a greater future than the public ones.Passage TwoQuestions 19-21 are based on the conversation you have just heard.19. A) 4,000 years ago. B) 3,000 years ago.C) 2,000 years ago. D) 1,000 years ago.20. A) The small bowl was put above the large bowl.B) The large bowl was put above the small bowl.C) The small bowl was put inside the large bowl.D) The large bowl consisted of two equal parts.21. A) Horsemen. B) Brass doors. C) Drops of water. D) Metal balls.Passage ThreeQuestions 22-25 are based on the conversation you have just heard.22. A) In a fast-food restaurant. B) At a shopping center.C) At a country fair. D) In a bakery.23. A) Avoid eating any food. B) Prepare the right type of pie to eat.C) Wash his hands thoroughly. D) Practice eating a pie quickly.24. A) On the table. B) Behind his back.C) Under his bottom. D) On his lap.25. A) Looking sideways to see how fast your neighbour eats.B) Eating from the outside toward the middle.C) Swallowing the pie with water.D) Holding the pie in the right position.Part II Reading Comprehension (30%)Passage OneWater projects in the United States gained a new rationale (根据) in the 1930’s as the nation suffered its worst economic depression and the Great Plains region suffered its worst drought in recorded history. As the economy sank into despair and unemployment rates increased, the political climate for direct federal government involvement in water projects improved. President Franklin Roosevelt’s first 100 days in office brought a number of new laws to deal with the severe economic depression that became known as the Great Depression. Two of these laws, the Tennessee Valley Authority Act of 1933 and the National Recovery Act of 1933 (NIRA), had particular significance for water resource development.The natural pattern of Tennessee River was characterized by large spring flows that produceddestructive floods and low summer flows that restricted navigation. The intensity and frequency of the events discouraged development and contributed to persistent poverty in the valley. To counter these natural obstacles, the Tennessee Valley Authority Act of 1933 created Tennessee Valley Authority (TV A), a public agency with broad powers to develop the Tennessee River system in the interest of navigation, flood control, and national defense, and to promote development in the region, including authority to build dams and reservoirs and to generate and sell hydroelectric power. The TV A is a unique institution in that it brings all the water-related functions of the federal government of the single body. The TV A used its authority to transform the Tennessee River into one of the most highly regulated rivers in the world within about two decades. The TVA inherited the Wilson Dam, and by the beginning of the Second World War it had completed six additional multipurpose dams with power plants and locks for navigation. Investments in dams and hydropower facilities within the Tennessee Valley also received high priority during the war.The NIRA authorized the creation of the Public Works Administration to create jobs while undertaking work of benefit to the community. The NIRA also gave the United States President unprecedented powers to initiate public works, including water projects. The Public Works Administration provided loans and grants to state and local governments and to federal agencies for municipal waterworks, sewage plants, irrigation, flood control, and waterpower projects.26. All of following are mentioned as resulting from the Great Depression EXCEPT ______.A) an increase in unemploymentB) a change in political thinkingC) a new study of the history of droughtsD) a different approach to water projects27. It can be inferred from the passage that before the 1930’s the role of the federal government in waterprojects was _______.A) more limited than it was after 1930B) more important than its role in other conservation projectsC) restricted to the Great Plains regionD) designed to help with drought recovery28. The word “unprecedented” (Para. 3) is closest in meaning to ______.A) not extensiveB) not existing beforeC) not used oftenD) not needing money29. Which of the following discouraged development of the Tennessee Valley prior to 1933?A) Laws imposed by the local government.B) The geographical features of the valley.C) The lack of suitable building materials.D) The effects of seasonal flows of the river.30. According to the passage, the Tennessee Valley Authority decided to ______.A) introduce rules to control the use of the Tennessee RiverB) build the Wilson DamC) reduce investment in hydropower facilities in the Tennessee ValleyD) increase the price of electricityPassage TwoWithin fifteen years Britain and other nations should be well on with the building of huge industrial complexes for the recycling of waste. The word rubbish could lose its meaning because everything which goes into the dumps would be made into something useful. Even the most dangerous and unpleasantwastes would provide energy if nothing else.The latest project is to take a city of around half a million inhabitants and discover exactly what raw materials go into it and what go out. The aim is to find out how much of these raw materials could be provided if a plant for recycling waste were built just outside the city. This plant would recycle not only metal such as steel, lead and copper, but also paper and rubber as well.Another new project is being set up to discover the best ways of sorting and separating the rubbish. When this project is complete, the rubbish will be processed like this: first, it will pass through sharp metal bars which will tear open the plastic bags in which rubbish is usually packed; then it will pass through a powerful fan to separate the lightest elements from the heavy solids; after that grounders and rollers break up everything that can be broken. Finally, the rubbish will pass under magnets, which will remove the bits of iron and steel; the rubber and plastic will then be sorted out in the final stage.The first full-scale giant recycling plants are, perhaps, fifteen years away. Indeed, with the growing cost of transporting rubbish to more distant dumps, some big cities will be forced to build their own recycling plants before long.31. The phrase “be well on with…” (Para. 1) most probably means _______.A) have completed what was startedB) get ready to startC) have achieved a great dealD) put an end to32. What is NOT mentioned as a part of the recycling process described in Paragraph 3?A) Breaking up whatever is breakable.B) Sharpening metal bars.C) Separating light elements from the heavy ones.D) Sorting out small pieces of metal.33. What’s the main reason for big cities to build their own recycling plants?A) To deal with wastes in a better way.B) To protect the environment from pollution.C) To get raw materials locally.D) To get big profits from those plants.34. The first full-scale huge recycling plants ______.A) began to operate fifteen years agoB) will probably take less than fifteen years to buildC) will be built fifteen years laterD) will probably be in operation in fifteen years35. The passage is mainly about ______.A) a cheap way to get energyB) the location of recycling plantsC) new ways of recycling wastesD) the protection of city environmentPassage ThreeIn 1972, a century after the first national park in the United States was established at Yellowstone, legislation was passed to create the National Marine Sanctuaries（国家海洋保护区）Program. The intent of this legislation was to provide protection to selected coastal habitats（栖息地）similar to that existing for land areas designated（指定）as national parks. The designation of an area a marine sanctuary indicates that it is a protected area, just as a national park is. People are permitted to visit and observe there, but living organisms and their environments may not be harmed or removed.The National Marine Sanctuary Program was created by the Marine Protection, Research and Sanctuaries Act of 1972. This authorizes the Secretary of Commerce to designate and manage areas of the marine environment with special national significance due to their conservation, recreational, ecological, historical, scientific, cultural, archeological, educational, or esthetic qualities as national marine sanctuaries. Initially, 70 sites were proposed as candidates for sanctuary status. Two and a half decades later, only fifteen sanctuaries had been designated, with half of these established after 1978. They range in size from the very small (less than 1 square kilometer) Fagatele Bay National Marine Sanctuary in American Samoa to the Monterey Bay National Marine Sanctuary in California, extending over 15,744 square kilometers.The National Marine Sanctuaries Program is a crucial part of new management practices in which whole communities of species, and not just individual species, are offered some degree of protection from habitat degradation and overexploitation. Only in this way can a reasonable degree of marine species diversity be maintained in a setting that also maintains the natural interrelationships that exist among these species.Several other types of marine protected areas exist in the United States and other countries. The National Estuarine Research Reserve System, managed by the United States government, includes 23 designated and protected estuaries（港湾）. Outside the United States, marine protected-area programs exist as marine parks, reserves, and preserves. Over 100 designated areas exist around the periphery of the Carbbean Sea. Others range from the well-known Australian Great Barrer Reef Marine Park to lesser-known parks in countries such as Thailand and Indonesia, where tourism is placing growing pressures on fragile coral reef systems. As state, national, and international agencies come to recognize the importance of conserving marine biodiversity, marine projected areas, whether as sanctuaries, parks, or estuarine reserves, will play an increasingly important role in preserving that diversity.36. What does the passage mainly talk about?A) Various marine conservation programs.B) Differences among marine parks, sanctuaries, and reserves.C) International agreements on coastal protection.D) Similarities between land and sea protected environments.37. The passage mentions the Monterey Bay National Marine Sanctuary in paragraph 2 as an example of asanctuary that ______.A) is worth protectingB) covers a large areaC) is the largest one in AmericaD) was designated by the Secretary of Commerce38. According to the passage, all of the following are achievements of the National Marine SanctuariesProgram EXCEPT ______.A) the discovery of several new marine organismsB) the preservation of connections between individual marine speciesC) the protection of coastal habitatsD) the establishment of areas where the public can observe marine life39. Based on the passage, ______ is regarded as a threat to marine areas outside the United States.A) limitations in financial supportB) the use of marine species as foodC) variability of the climateD) increases in tourism40. The word “periphery” in paragraph 4 is closest in meaning to ______.A) depthB) landmassC) outer edgeD) habitatPassage FourIt is all very well to blame traffic jams, the cost of petrol and the quick pace of modern life, but manners on the roads are becoming horrible. Everybody knows that the nicest men become monsters behind the wheel. You might tolerate the odd road-hog, the rude and inconsiderate driver, but nowadays the well-mannered motorist is the exception to the rule.Road politeness is not only good manners, but good sense too. It takes the most coolheaded and good-tempered of drivers to resist the temptation to revenge when subjected to uncivilized behavior. On the other hand, a little politeness goes a long way towards relieving the tensions of motoring. A friendly nod or a wave of acknowledgement in response to an act of politeness helps to create an atmosphere of goodwill and tolerance so necessary in modern traffic conditions. But such acknowledgements of politeness are all too rare today.However, misplaced politeness can also be dangerous. Typical examples are the driver who brakes violently to allow a car to emerge from a side street at some hazard to following traffic, when a few seconds later the road would be clear anyway; or the man who waves a child across a zebra crossing into the path of oncoming vehicles that may be unable to stop in time. The same goes for encouraging old ladies to cross the road wherever and whenever they care to. It always amazes me that the highways are not covered with the dead bodies of these grannies.A veteran driver, whose manners are faultless, told me it would help if motorists learnt to filter correctly into traffic streams one at a time without causing the total blockages that give rise to bad temper. Unfortunately, modern motorists can’t even learn to drive, let alone master the subtler aspects of roadsmanship. Years ago the experts warned us that the car-ownership explosion would demand a lot more give-and-take from all road users. It is high time for all of us to take this message to heart.41. Accoding to this passage, troubles on the road are primarily caused by _______.A) people’s attitude towards the road-hogB) the rhythm of modern lifeC) the behavior of the driverD) traffic conditions42. The sentence “You might tolerate the odd-hog… the rule.” (Para. 1) implies that _______.A) our society is unjust towards well-mannered motoristsB) rude drivers can be met only occasionallyC) the well-mannered motorist cannot tolerate the road-hogD) nowadays impolite drivers constitute the majority of motorists43. By “good sense” in paragraph 2, the writer means _______.A) the driver’s ability to understand and react reasonablyB) the driver’s prompt response to difficult and severe conditionsC) the driver’s tolerance of rude or even savage behaviorD) the driver’s acknowledgement of politeness and regulations44. Experts have long pointed out that in the face of car-ownership explosion, _______.A) road users should make more sacrificeB) drivers should be ready to yield to each otherC) drivers should have more communication among themselvesD) drivers will suffer great loss if they pay no respect to others45. In the writer’s opinion, _______.A) strict traffic regulations are badly neededB) drivers should apply road politeness properlyC) rude drivers should be punishedD) drivers should avoid traffic jamsPart III Vocabulary and Structure(10%)46. We need someone really ______ who can organize the office and make it run smoothly.A) crucial B) realistic C) essential D) efficient47. Their refusal to compromise is a major _______ that stands in the way of further peace talks.A) obstacle B) complication C) entity D) hazard48. Under normal circumstances the body can _______ these naturally occurring substances into vitamins.A) convert B) render C) derive D) originate49. He should ______ what he’s good at, and not switch to something he knows nothing about.A) take on B) stick to C) go after D) live on50. Many social problems are caused by the uneven ______ of wealth.A) equality B) justice C) distribution D) volume51. The doctor ______ Billy’s operation with x-rays and special exercises to make him stronger.A) went after B) followed up C) started up D) took on52. Obviously, no teacher has _______ patience. Even Larry, who is always kind and tolerant, lost histemper on that particular occasion.A) infinite B) definite C) spectacular D) plural53. His total worldly possessions ______ little more than the clothes he stood up in.A) amounted to B) settled for C) turned up D) came at54. Our director had ______ on the matter for a long time before he made the decision.A) hushed B) thrashed C) pondered D) suspended55. The United Nations was supposed to ______ the role of global peace-keeper.A) contend B) nurture C) carve D) undertakeChoose the words and expressions that are similar in meaning to the underlined parts. (找同义词) 56. If an object is suspended from any point on the vertical line passing through its center of gravity, theobject will remain stationary.A) secure B) flexible C) motionless D) hung57. According to a United States law passed in 1986, states participating in daylight saving timesimultaneously advance their clocks one hour on the last Sunday in April.A) conceptually B) systematically C) at the same time D) for a brief period58. The Hudson River School was the name of the first group of American artists to develop acharacteristic style of landscape paintings.A) territory B) scenery C) spectrum D) groundwork59. Some cells, such as epithelia, proliferate more rapidly when the body is asleep than when it is awake.A) cluster B) multiply C) adapt D) heal60. That morning, on Mount Tai, I saw the most spectacular sunrise in my life.A) adolescent B) mysterious C) opaque D) impressive61. However, the new law, once passed, will render the Bridlington agreement illegal by giving workersthe right to join unions of their choice.A) convert B) cancel C) make D) hold62. The mayor promised to trim the city budget without cutting essential services.A) appropriate B) fundamental C) equivalent D) sparkled63. The destruction of the Twin Towers in New York City provoked shock and anger throughout the world.A) aroused B) tempted C) summoned D) enveloped64. The poetry of Ezra Pound is sometimes difficult to understand because it contains so many obscurereferences.A) dazzling B) widespread C) plural D) unrecognizable65. Dr. Light, who is reputed to be one of the best surgeons in London, performed the operation andsuccessfully removed the tumor in her lungs.A) considered B) confessed C) thrilled D) perceivedPart IV Cloze(10%)Direction:There are 20 blanks in the following passage. For each blank there are four choices marked A),B), C) and D) on the right side of the paper. You should choose the one that best fits into thepassage.Part V Word Formation (5%)1.There is a _____ of two things that are important: culture and space. (combine)2.If he had failed in the old society, he would be _____ and pessimistic. (courage)3.But instead of liberating us, technology has _________us. (slave)4.They worked hard and finally achieved the ________result. (prospect)5.The opening speeches sounded more like _________of war than offerings of peace. (declare)Part VI Translation(20%)Translate the following sentences into Chinese.1. It takes no longer to prepare well for one interview than to wander in half-prepared for five. And your prospects for success will be many times better.2. It may be that the Euro-centered American nation is declining as it gives way to a new pacific civilization that will include, but not be limited to, America.3. I’m struck that I am walking on one of the engineering wonders of the world.4. We need to develop a conception of ourselves in the universe not as the master species but as the servant species.5. The stress we feel arises not from a shortage of time, but from the surfeit of things we try to cram into it. Choose the proper words and phrases in the box to translate the following sentences into English.6．除去毁灭性的洪水，饥荒也广泛存在，并已导致了各种各样的问题。

pax romana英文解释

pax romana英文解释Pax Romana: A Period of Peace and Prosperity in the Ancient Roman Empire.The Pax Romana, often translated as the "Roman Peace," refers to the period of relative peace and stability that existed within the borders of the ancient Roman Empire, particularly during the 1st and 2nd centuries AD. This era marked a significant turning point in Roman history, characterized by a reduction in major conflicts and an increase in economic prosperity and cultural exchange.The Pax Romana was not a static period but rather an evolving concept that reflected the changing political and military realities of the Roman world. It began with the consolidation of power by Augustus, the first emperor of the Roman Empire, who established a system of imperial governance that prioritized stability and security. Augustus's reign marked a transition from the republican era to the imperial period, and his policies set the tonefor the Pax Romana.One of the key factors contributing to the Pax Romana was the establishment of a strong central government led by the emperor. This centralized authority allowed for more effective control over the provinces and a reduction in the frequency of civil wars and rebellions. The emperor was supported by a bureaucracy of loyal officials who implemented policies designed to maintain peace and order.The Pax Romana was also facilitated by the development of a professional army under the control of the emperor. This army, composed primarily of volunteers rather than conscripts, was well-trained and equipped, and it was used to maintain control over the provinces and suppress any threats to the emperor's authority. The army's effectiveness was further enhanced by the construction of a network of roads and fortifications that linked the provinces together, facilitating the rapid deployment of troops.Economically, the Pax Romana saw a significant increasein trade and commerce within the empire. The development of a coherent currency system, improvements in transportation networks, and the establishment of a system of laws that protected property rights all contributed to the growth of economic prosperity. The Pax Romana also saw the emergenceof new cities and the expansion of existing ones, as wellas an increase in the production of goods such as pottery, glass, and metalwork.Cultural exchange also flourished during the Pax Romana. The empire's vast territory encompassed a diverse range of peoples and cultures, and the Pax Romana allowed for the spread of ideas, art, and technology across these different regions. For example, the spread of Greek culture and philosophy throughout the empire had a profound impact on Roman intellectual life, while the adoption of Eastern religious practices such as Mithraism and Christianity introduced new spiritual traditions to the Roman world.Despite the relative peace and prosperity of the Pax Romana, the period was not entirely without conflict. The Roman Empire was still扩张性的, seeking to expand itsborders and consolidate its power. This led to conflicts with neighboring civilizations such as the Parthians, Germans, and Jews, as well as internal rebellions and uprisings. However, these conflicts were generally less frequent and less destructive than those of previous periods, and they were typically contained within specific regions rather than spilling over into widespread warfare.In conclusion, the Pax Romana represents a significant era of peace and prosperity in the ancient Roman Empire. It was facilitated by the establishment of a strong central government, a professional army, and a network of roads and fortifications that linked the provinces together. Economic growth and cultural exchange flourished during this period, leading to the emergence of new cities and the spread of ideas and technologies across the empire. While the Pax Romana was not entirely without conflict, it nonetheless marked a significant turning point in Roman history, laying the foundation for the Empire's subsequent growth and influence.。

金字塔设首家观景餐厅

...wIll被誉为世界七大奇迹之一的埃及金字塔每年吸引着许多游客，近期在其旁建造的塊$厅为游客提供了诸多便利之处。

Restaurant opensnext to Egypt，s pyramids金字塔设首家观景餐厅陕西吕品题材体裁文章词数建议用时生活说明文3246分钟3.reassemble/|ril"'sembl/重新组装;重新装配1.renovation/l ren"'veljn/n.翻新；修复2.antiquity/^n'tlkwOti/n.古迹A restaurant has opened near the Great Pyramid ofGiza and the Great Sphinx in Cairo,d NineLounge,the restaurant falls within a larger renovationplan for the Giza Pyramids that amounts up to LE400million,which will also include future services such asshopping and several other cafes and restaurants.The1,300-square-meter Nine Lounge opened on October20,2020and is now the closest restaurant to Egypt's mostpopular tourist attraction.According to Mostafa Waziri of the country's antiquities council,people used to complain that there were no special services for tourists in the area:"No cafeteria,no restaurant,nothing that can be offered to visitors.#He says tourists now have a restaurant that offers a better view than any other place in the world.There are also plans for other attractions like a cinema to be built on the site, while a fleet of electric buses are being made available to help visitors move around.The new facilities are all easily taken apart and reassembled so as to protect the antiquities.The Great52...悅簇蓋hiPyramid of Giza is147meters tall,while the Great Sphinx,which has the head of a human and the body of a lion,is20meters high and73meters long.They were built about4,500years ago,both of which are Egypt's famous landmarks.The changes at the plateau are part of wider efforts to develop key tourist sites in the country. The Grand Egyptian Museum will also open near the Giza Pyramids in2021——10years after it was meant to open.It will be the largest archaeological museum in the world.The projects are part of a plan to improve tourist sites in Egypt.Tourism accounts for up to15per cent of Egypt's national output.However,officials have said previously the sector is losing around$1billion each month after largely shutting down for several months since March because of the spread of coronavirus.Reading/^丿"Check1.What can we learn about Nine Lounge?A.It was built to protect the Great Sphinx better.B.It is situated in the Great Pyramid of Giza.C.It includes shops and other cafes.D.It takes up1,300square meters.2.How did tourists feel about services in Egypt's tourist attraction?A.Content.B.Passionate.C.Dissatisfied.D.Embarrassed.3.Why are the new facilities easily taken apart?A.To save building costs.B.To protect the tourist attraction.C.To prepare for future construction.D.To provide better service for tourists.4.When was the Grand Egyptian Museum meant to open?A.In2021.B.In2020.C.In2010.D.In2011.Difficult sentenceHe says tourists now have a restaurant that offers a better view than any other place in the world.他说,游客现在可以在这样一家餐馆看到世界上最美的风景。

2020-2022年近3年高考英语真题分项版汇编：专题07 名词性从句和定语从句(教师版含解析)

专题07名词性从句和定语从句2022年高考真题1（2022新高考I卷）The GPNP is intended to provide stronger protection for all the species________live within the Giant Panda Range and significantly improve the health of the ecosystem in the area.答案：that解析：考查定语从句关系词。

句意：该计划旨在为生活在Giant Panda Range的所有物种提供更有力的保护，并显著改善该地区的生态系统健康。

设空处为关系词引导限制性定语从句，先行词等于关系词，设空处在从句中作指物的主语，先行词为species，且先行词前为all修饰，只能用关系代词that。

故填that。

2（2022全国甲卷）On the1,100.Kilometer journey,the man Cao Shengkang,_________lost his eyesight at the age of eight in a car accident,crossed40cities and counties in three province.答案：who解析：考查定语从句。

句意：在1100公里的旅程中，8岁时因一次车祸失明的男子曹盛康穿过了三个省的40个城市和县。

分析句子结合句意可知，此处是非限定性定语从句，先行词为Cao Shengkang，指人，在从句中作主语，应用关系代词who引导。

故填who。

3（2022年浙江1月）Kim Cobb,a professor at the Georgia Institute of Technology in Atlanta,is one of a small but growing minority of academics__________are cutting back on their air travel because of climate change.答案：that/who解析：考查定语从句。

88蝴蝶

The 88 Butterfly, Diaethria clymena, facts and information(Part 1)The 88 butterfly (Diaethria clymena) is one many exotic and mysterious butterflies that are considered natural treasures of the sub-tropical Amazon rainforest. They are members of the Callicorini tribe, the Diaethria genus is also the third most diverse genus in the rather extensive Callicorini tribe. The D. clymena was first described by Entomologist Pieter Cramer in 1775. Thesebutterflies are often confused with other Diaethria butterflies such as the 89butterfly, Diaethria neglecta. Common mistakes are often the result of easily overlooked details in the all to familiar patterns among species in the genus. The only way to tell them apart is through distinguishing the amount of read and spacing in the familiar patterns, kind of like an expert stage of spot the difference. This, I must say, is one of the most difficult parts of identifying butterflies at the species and even more complex form level.As adults (butterflies) they are particularly fond of rotting fruits and urine soaked, sandy patches along the river edges of secondary forest vegetation. The larval host plants are the Trema’s, which belong to the Ulmaceae family of flowering plants. They are timid creatures, hopping along from patch to patch at the tiniest disturbances. When not in butterfly aggregation spots they can be found in small groups no more than a handful at a time.A unique characteristic the D. clymena share with the recently discussed Cracker, Hamadryas butterfly is the ability to hear. They have what is known as a Vogel’s organ, a tympanal based auditory instrument (fancy word for ears) that is located at the base of the forewing.That’s it for part 1, in part 2 I’ll go more into the transformation and life cycle of the Diaethria clymena.。

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II. ESTIMATE OF BHATTACHARYYA COEFFICIENT FOR MULTINOMIAL DISTRIBUTIONS Let the class-conditional densities for a feature x in a two-class problem be given by
pl(x)
N
=
i=l
E
cj(x
-ห้องสมุดไป่ตู้
i)
and I. INTRODUCTION N Several recent investigations which appear in pattern recogniP2(X) = flib(x - i) tion literature are directed towards utilizing various distance measures and information measures for the evaluation of such- that N N statistical features and the determination of a bound on the i= i = 1. performance of pattern classifiers [1 ]- [5 ]. Some such measures which are widely used are the Bhattacharyya distance B, the divergence J and the mutual information I. The rationale which Then, the Bhattacharyya coefficient defined as is proposed for using these measures is that they are computationally more manageable than the probability of misp = f P1(x)p2(x) dx classification Pe. Therefore, if one can bound Pe in terms of the distance or the information measures, and since the effectiveness is given by N of features is directly related to Pe, the features can also be P(axfl) = E \/a7f. evaluated using these measures. Devijver, in a recent paper [6], conjectures and gives evidence which supports the interesting dilemma that the expressions which give a tight bound on Pe where a and f denote the sets of parameters {. -,c,a} and are computationally unmanageable, whereas, the manageable {,3R,.. .,/3,}, respectively. expressions give a rather loose bound on Pe. This may be one The Bhattacharyya distance is defined as of the reasons why Kanal, in a recent review of pattern recognition [7], mentions that "the primary utility of the distance B = -ln p. measures and corresponding bounds is for theoretical investigations." It should be pointed out here that the bounds on Pe For simplicity we study the properties of an estimate of p rather than that of B. Let ,i and 13i denote the maximum likelihood Manuscript received January 21, 1976; revised March 22, 1976 and June 1, estimates of o(x and /Pi, respectively, i = 1,---.,N, based on m 1976. This work was supported in part by the Air Force Office of Scientific samples available from each of the two classes: Research under Grant AFOSR72-2351.
763
On an Estimate of the Bhattacharyya Distance A. K. JAIN, MEMBER, IEEE
Abstract-The behavior of an estimate of the Bhattacharyya distance when used as a feature selection criterion is investigated. We have shown that when features have multinomial or univariate Gaussian distributions, this estimate is biased and consistent. The bias and the variance of the estimate is not only a function of the number of training samples but also depends on the true parameters of the densities. These results suggest a careful analysis of the situations where distance measures are used to evaluate features.
available in terms of the distance measures are applicable only when the class-conditional densities are completely known, a quite unrealistic situation in practice. It is generally uncertain how the distance measures will behave if the estimated densities are substituted for the true ones in the expressions for these measures. Heydorn [8] has obtained an estimate of the Battacharyya coefficient in terms of the Parzen estimate of the densities, but the performance of this estimate as a function of sample size and the true distributions is not known. In this paper we study the behavior of an estimate of Bhattacharyya distance when the form of the class-conditional densities is known and a finite number of labeled samples are available to estimate the parameters of the densities. We will concern ourselves mainly with the following question. How good is the estimate of Bhattacharyya distance as a feature evaluation criterion? In particular, we will determine the expected value and the variance of an estimate of Bhattacharyya distance. Although Kailath [4] gives expressions of Bhattacharyya distance for several densities, we will restrict ourselves to situations where the densities are multinomial and univariate Gaussian with unknown parameters. Our analysis is similar to that used by Basharin [9] in connection with determining the properties of an estimate of entropy and to that of Zvarova [10] who studied the behavior of a sample estimator of Renyi's information of order cz. The approach which we take can, in principle, be used for other probability distributions and different distance measures.