人教网刊《半亩历史》2013年度征稿启事

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初二历史中国近代民族工业的发展试题答案及解析

初二历史中国近代民族工业的发展试题答案及解析1.张謇放弃高官厚禄，回家创办实业，但他的工厂最终被吞并。

下列对此事的评价，正确的是（）。

A．市场有风险，这是竞争的结果B．张謇为一介书生，不懂市场，失败是必然C．在多重挤压之下，中国民族工业创业艰难D．“实业救国”口号被实践证明是错误的【答案】C【解析】此题考查的近代我国民族工业发展的相关史实。

张謇在甲午中日战争后创办的大生纱厂，在第一次世界大战期间，由于帝国主义暂时放松了对中国民族资本主义的压迫，由于辛亥革命冲击了封建制度，有一定的发展。

但一战后帝国主义经济势力卷土重来，张建德工厂被吞并。

因为中国半殖民地本封建社会，我国民族工业受帝国主义封建主义的压迫，发展艰难曲折。

故此题选择答案C。

【考点】人教新课标八年级历史上册·经济和社会生活·中国近代民族工业的发展。

2.中国近代史上民族工业发展的“黄金时代”是在（）A．洋务运动时期B．甲午战争以后C．第一次世界大战期间D．抗战胜利以后【答案】C【解析】本题考查的是中国近代民族工业的发展历程。

第一次世界大战期间，帝国主义列强忙于战争，无暇东顾，暂时放松了对中国的经济侵略，给中国的民族工业带来了短暂发展的“黄金时代”，所以答案选C。

【考点】北师大版八年级上册·近代化的艰难起步·近代工业的发展3.在人教网刊《半亩历史》的编后絮语中，有过这样一句话：“他中过状元，本来有很好的仕途，却生不逢时，所以毅然放弃仕途，实业救国。

”你认为这句话中所提到的“他”是A．詹天佑B．侯德榜C．张謇D．严复【答案】C【解析】本题主要考查近代中国民族资本主义发展的情况，由材料中“中过状元”“放弃仕途，实业救国” 等信息可知材料中“他”指的是张謇，依据已学知识可知张謇是清末状元，中国近代实业家、政治家、教育家，主张“实业救国”，中国棉纺织领域早期的开拓者。

故选C。

【考点】人教新课标八年级上册·中国近代民族工业的发展·张謇4.随着民族危机步步加深，近代中国出现多种救国思潮。

中文CSSCI的杂志有哪些

中文CSSCI的杂志有哪些
CSSCI期刊就是南大核心期刊，南大核心期刊与北大核心期刊相比，发表更具难度，期刊的数量也要少一些，很多科研工作者都有发表南大核心期刊的要求，南大核心文章的写作大家可以选择自己擅长的领域来选题，如果是别人已经写烂的选题，作者再次写作时就必须要有新意有亮点，文章不要让行家一眼就发现有很多错误，这样很快就打回来了，文章整体看起来要好看，特别是图表要嵌入的规范，CSSCI写作完毕后就是要投稿了，中文CSSCI的杂志有哪些?
《北京大学教育评论》旨在贯彻“双百”方针，繁荣教育科学研究，为教育学学科建设及教育改革和发展服务。

刊名由著名教育家、前北京大学校长蔡元培先生遗墨集字而成，前身为《高等教育论坛》。

《湖南社会科学》坚持以马列主义、毛泽东思想、邓小平理论和“三个代表”重要思想为指导，以理论联系实际，突出反映改革开放的理论问题和实际问题研究为特点，坚持党的基本路线，贯彻“双百”方针，为两个文明建设，为繁荣社会科学，促进湖南经济发展服务。

《华东经济管理》系华东地区十几所高等院校联合主办的国内外发行的经济管理类学术性月刊。

1994年被台湾作为大陆重点期刊收录入《中文期刊指南》;1999年获安徽高等文科学报一等奖、中文核心期刊(1992)、2011年度中国人民大学《复印报刊资料》管理学学术期刊全文转载排名中，在所涉514家管理类期刊中位列第20，成为《复印报刊资料》重要转载来源期刊。

南大核心期刊发表不易，对作者的学术水平要求是相当高的，所以，大家平时一定要多多阅读一些相关的文章，多多动笔练习，写出好文章可不是一天两天就能达到的，有关于南大核心期刊发表的疑问可以咨询鸣网在线客服。

八年级上历史期末模拟

试卷第1页，总7页绝密★启用前 2014-2015学年度???学校1月月考卷试卷副标题考试范围：xxx ；考试时间：100分钟；命题人：xxx 注意事项：1．答题前填写好自己的姓名、班级、考号等信息 2．请将答案正确填写在答题卡上第I 卷（选择题）请点击修改第I 卷的文字说明一、选择题（题型注释） 1．中国近代史是一部中国人民的屈辱史和血泪史，中国近代和西方列强签定了一系列不平等条约。

以下赔款最多的条约是: （） A.《辛丑条约》 B.《南京条约》 C.《北京条约》 D.《马关条约》 2．历史遗址是我们了解、研究、反思历史的重要场所，下图所示遗址反映的历史事件是 A ．南京大屠杀 B ．卢沟桥事变 C ．六五隧道窒息惨案 D ．胡世合惨案 3．爱国诗人丘逢甲在《春愁》中写道：“四百万人同一哭，去年今日割台湾。

”诗中内容能让人联想起中国近代哪个屈辱条约 A ．《南京条约》 B.《瑷珲条约》 C.《马关条约》 D.《辛丑条约》 4．93年前，中国革命风云激荡，在北京青年学生的带动下爆发了轰轰烈烈的试卷第2页，总7页五四运动。

五四精神的主要内涵是 A. 爱国、民主 B. 改革、开放 C. 爱国、变法 D. 变法、革命 5．1924年5月，在广州黄埔创办了陆军军官学校的人是（） A.孙中山 B.周恩来 C.廖仲恺 D.蒋介石 6．1894年慈禧太后六十大寿，清政府忙于庆祝活动，此时日本入侵，清军战败。

后来有人在北京城门写下对联：“万寿无疆，普天同庆。

三军败绩，割地求和。

”对联中“割地求和”是指清政府签订了 A ．《瑷珲条约》 B ．《北京条约》 C ．《马关条约》 D ．《辛丑条约》7．在戊戌变法法令中，最能体现变法性质的是（）A.开办新学堂，翻译西方书籍，创办报刊，开放言论。

B.鼓励私人兴办工矿企业C.改革政府机构，裁撤冗官，任用维新人士D.训练新式军队8．每年的6月26日为“国际禁毒日”。

One-Dimensional Models

Accepted by ASME J. of Biomechanical Engineering on 03/10/2006One-Dimensional Models of the Human Biliary SystemW.G. Li a , X.Y. Luo b, A.G. Johnson c, N.A.Hill b, N. Bird c, & S.B. Chin aa Department of Mechanical Engineering, University of Sheffield, Sheffield, S1 3JD, UKb Department of Mathematics, University of Glasgow, Glasgow, G12 8QW, UKc Academic Surgical Unit, Royal Hallamshire Hospital, Sheffield, S10 2JF, UKCorresponding Author:Dr. X.Y. LuoDepartment of Mathematics,University of Glasgow,Glasgow, G12 8QW, UKFax: 0044-141-330 4111E-mail: X.Y.Luo@AbstractThis paper studies two one-dimensional models to estimate the pressure drop in the normal human biliary system for Reynolds number up to 20. Excessive pressure drop during bile emptying and refilling may result in incomplete bile emptying, leading to stasis and subsequent formation of gallbladder stones. The models were developed following the group’s previous work on the cystic duct using numerical simulations. Using these models, the effects of the biliary system geometry, elastic property of the cystic duct, and bile viscosity on the pressure drop can be studied more efficiently than with full numerical approaches. It was found that the maximum pressure drop occurs during bile emptying immediately after a meal, and is greatly influenced by the viscosity of the bile and the geometric configuration of the cystic duct, i.e. patients with more viscous bile or with a cystic duct containing more baffles or a longer length, have the greatest pressure drop. It is found that the most significant parameter is the diameter of the cystic duct; a 1% decrease in the diameter increases the pressure drop by up to 4.3%. The effects of the baffle height ratio and number of baffles on the pressure drop are reflected in the fact that these effectively change the equivalent diameter and length of the cystic duct. The effect of the Young’s modulus on the pressure drop is important only if it is lower than 400Pa; above this value, a rigid-walled model gives a good estimate of the pressure drop in the system for the parameters studied.Keywords: bile flow, cystic duct, gallstone, pressure dropNomenclatureACross-sectional area of collapsed ductm 2 0A Cross-sectional area of duct at zero transmural pressure m 2 1ACross-sectional area of flow at point 1 in Fig. 4 m 2 2A Cross-sectional area of the flow at point 2 in Fig. 4 m 2 1c Sudden contraction head-loss coefficient 2cSudden expansion head-loss coefficient 3c Head loss coefficient in a bend 4cHead loss coefficient in a 90o benddInner diameter of duct mm EYoung’s modulus of materials Pa fDarcy friction factor hThickness of wall or baffle mm HBaffle heightmm j Number of nodeJMaximum number of element p KStiffness of wall Pa LLength of ductm m L Equivalent length due to minor pressure loss m n Number of bafflesc nMaximum number of baffles p Internal duct pressure Pa e p External duct pressure Pa QBile flow rateml/min ReReynolds number, Re ud ν= r Inner radius of duct, πA r =mtTime min uBile velocity in cystic duct, A Q u = m/s V Bile volume in gallbladder ml x Duct centre-line coordinate m α Area ratio, 0A A =αμBile dynamic viscositymPa.s νBile kinematic viscosity, νμρ= mm 2/s θ The half of central angle of baffle cut rad ρDensity of bilekg/m 3 σPoisson’s ratioξBaffle height ratio, CD H d ξ=L Δ Distance between two successive baffles in cystic duct m p ΔPressure dropPa m p Δ Minor pressure drop in cystic ductPa te p Δ Minor pressure drop in T-junction during emptying Pa th p ΔMinor pressure drop in T-junction during refill Pa x ΔInterval of elementm Subscriptsb Baffle CBD Common bile ductCD Cystic duct CHDCommon hepatic ductEM Emptyingeq Equivalent id Ideal, straight and circular pipe inInlet of ductmax Maximum value min Minimum value outOutlet of ductRF Refilling1 IntroductionBiliary diseases such as cholelithiasis and cholecystitis necessitate surgical removal of the gallbladder (GB), which is the most commonly performed abdominal operation in the West. Some 60,000 operations for gallbladder disease are performed in the UK each year [1] at a cost to the National Health Service (NHS) of approximately £60 million per annum [2]. In order to understand the causes of these diseases, it is important to understand the physiological and mechanical functions of the human biliary system. The human biliary system consists of the gallbladder, cystic duct, common hepatic duct and common bile duct (Fig. 1). The human gallbladder is a thin-walled, pear-shaped sac which measures approximately 7-10cm in length and ~3cm in width. Its average storage capacity is 20-30ml. The human cystic duct is approximately 3.5cm long and 3mm wide and merges with the common bile duct. The mucosa of the proximal cystic duct is arranged into 3-7 crescentic folds or valves known as the spiral valves of Heister. The human common duct is normally about 10-15cm long and 5mm wide, in which the hepatic common duct is ~4cm long. The common bile duct merges with the pancreatic duct before entering the duodenum at the ampulla [4].Whilst the anatomical and physiological aspects of the human biliary system have been studied extensively, a little is known about flow mechanics in the system. Torsoli and Ramorino [5] measured pressures in the biliary tree and found them to vary from 0-14cm H2O (1cm H2O=100Pa) in the resting gallbladder to approximately 12-20cm H2O in the common bile duct. Earlier experimental work by Rodkiewcz and Otto [6] showed that bile behaves like a Newtonian fluid, although this has been challenged recently [7, 8, 9]. Kimura [10] found that the relative viscosity of bile is between 1.8-8.0, while Joel [11] found it is between 1.77-2.59. The relative viscosity is defined as the dynamic viscosity of the investigated fluid compared with that of distilled water, both at the same temperature. Tera [12] measured the dynamic viscosity of gallbladder bile by using eight 8cm-long capillary tubes with a diameter of 0.2mm. It was found that the normal gallbladder bile was layered and the relative viscosity of the top, thinnest layer was 2.1 and the bottom thickest layer was 5.1. Bouchier et al [13] also reported that relative viscosity, determined by a capillary flow viscometer, was greater in pathological gallbladder bile than normal gallbladder bile and both were more viscous than hepatic duct bile. Although the concentration of normal gallbladder bile affected the bileviscosity, in pathological and hepatic bile, the content of mucous was the major factor determining viscosity. Cowie et al [14] showed that the mean viscosity of bile from gallbladders containing stones was greater than that from healthy ones. The presence of mucous in gallbladders with stones was likely to account for the differences in viscosity based on the viscosity results using a Cannon-Fiske capillary viscometer at room temperature.The complicated geometry of the biliary tree makes it difficult to estimate the pressure drop during bile emptying using the Poiseuille formula. Rodkiewiz et al [15] found that flow of bile in the extrahepatic biliary tree of dog was related to the associated pressure drop by a power law and differed from that for laminar flow in a rigid tube. Dodds et al [16] calculated the volume variations of the gallbladder during emptying using the ellipsoid and sum-of-cylinders methods from the gallbladder images. Jazrawi et al [17] performed simultaneous scintigraphy and ultrasonography for 14 patients with gallstones and 11 healthy controls and studied the postprandial refilling, turnover of bile, and turnover index. They found that in postprandial healthy controls, the gallbladder handles up to six times its basal volume within 90min, but this turnover of bile is markedly reduced in cholelithiasis causing a reduced washout effect of the gallbladder contents, including cholesterol crystals (They didn’t actually measure the cholesterol crystals). Deenitchin [18] investigated the relationships between a complex cystic duct and cholelithiasis in 250 patients with cholelithiasis and 250 healthy controls. It was found that the patients with gallstones had significantly longer and narrower cystic ducts than those without stones. The results suggested that complex geometry of the cystic ducts may play an important role in cholelithiasis. An increase in the cystic duct resistance has been shown to result in sludge formation and eventually stones in the gallbladder [19, 20, 21, 22, 23]. Recently, Bird et al [24] have investigated the effects of different geometries and their anatomical functions of the cystic ducts.It is now generally accepted that prolonged stasis of bile in the gallbladder is a significant contributing factor to gallstone formation, suggesting that fluid mechanics, in particular, the pressure drop which is required to overcome the resistance of bile flow during emptying, may play an important role in gallstone formation. Unusually high gallbladder pressures could be a cause of acute pain observed in vivo, and also indicate that the gallbladder could not empty satisfactorily, increasing the likelihood of forming cholesterol crystals.Ooi et al [25] performed a detailed numerical study on flow in two- and three-dimensional cystic duct models. The cystic duct models were generated from patients’ operative cholangiograms and acrylic casts. The pressure drops in these models were compared with that of an idealised straight duct with regular baffles or spiral structures. The influences of different baffle heights, numbers, and Reynolds numbers on the pressure drop were investigated. They found that an idealised duct model, such as a straight duct with baffles, gives qualitative measurements that agree with the realistic cast models from two different patients. Experimental work has also been carried out to validate the CFD predictions in the simplified ducts [26]. Thus the simplified models can be used to provide some physical insights into the general influence of cystic duct geometry on the pressure drop [25]. However, their CFD modelling was limited to rigid cystic duct models only, an extending it to compliant model will be very much time consuming.In this paper, in order to obtain a global view of the total pressure drop in the whole biliary system and to consider the importance of the effects of fluid-structure interaction in the human cystic duct, we propose two one-dimensional models of the human biliary system, one with a rigid wall and one with an elastic wall. These models are based on the three-dimensional straight duct with regular baffles used by Ooi et al [25]. The rigid model is validated against the three-dimensional simulations, and the differences between the elastic and rigid models are discussed. Using these models, the effects of physical parameters such as the cystic duct length, diameter, baffle height ratio, number of baffles, the Young’s modulus, and the bile viscosity, on the pressure drop are studied in detail. Both refilling and emptying processes are modelled, and the bile flow in the hepatic and common bile ducts is also taken into consideration. It is hoped that these models can be further developed to provide some fast, qualitative estimates of pressure drop based on real time in vivo data of patients’ biliary systems and therefore be used to aid clinical diagnosis in the longer term.The remainder of the paper is organized as follows. The characteristics of geometry and flow are described in Section 2, and the one-dimensional models are introduced in Section 3. The results and discussion are given in Section 4, followed by the conclusions.2 Characteristics of Geometry and FlowAnatomical descriptions of the biliary system date back to the 18th century when Heister [4] reported spiralling features in the lumen of the cystic duct and called them “valves”. Although later researchers doubted the valvular function, the term “valves of Heister” is still in use. The gross anatomy of the biliary system shown in Fig.1 begins from the gallbladder neck which funnels into a cystic duct. Spiralling mucous membranes are generally prominent in the proximal part of the cystic duct (pars spiralis or pars convoluta ) which then smoothes out to form a circular lumen at the distal end (pars glabra ). Although the actual geometry of the cystic, common hepatic and bile ducts is very complicated and subject dependent, and the ducts are all curved, to obtain a system view we can schematically represent the human biliary system as in Fig. 2.The flow directions of the bile during gallbladder emptying immediately after meal, and during refilling are also shown in Fig. 2. Usually, it takes about half an hour for emptying and several hours (until the next meal) for refilling. The gallbladder volume variation with time in both emptying and refilling is shown in Fig. 3 [4]. From this figure, we can derive the corresponding flow rate (or volume flux) Q (=dV dt ). For a healthy person, the average bile density ρ is about 1000kg/m 3, the same as water, and the range of diameter of the cystic duct is about CD d =1-4mm [24]. The temporal acceleration of bile (u t ρ∂) is approximately 10-3 m/s 2 in the emptying phase and 10-5 m/s 2 in the refilling, and can therefore be ignored in our model. In addition, the maximum Reynolds number (Re =4CD Q d πν) estimated for a cystic duct with diameter of 1mm and bile kinematical viscosity ν=1.275 mm 2/s is about 20 duringnormal emptying, and even smaller during refilling. Hence the flow is laminar. Finally, for a healthy person without gallstones, the bile can be reasonably considered as a Newtonian fluid [27].3 The One-Dimensional ModelsThe pressure drop during emptying is believed to have a link with the stone formation in gallbladder [18]. Our primary aim, therefore, is to predict this pressure drop in a mathematical model of the human biliary system. It is noted that the key structure contributing to the pressure drop is the cystic duct, while the hepatic and common bile ducts offer little resistance or geometric changes during emptying and refilling. Therefore to simplify the pressure dropprediction, the modelling focuses on the non-linear flow features in the cystic duct, while Poiseuille flow is assumed in the other two biliary ducts. In the following, the effects of the baffles in the cystic duct are considered in order to determine the equivalent diameter and length. The effects of the elastic wall are then considered on a straight model of the cystic duct using the concept of equivalent diameter and length.3.1 The Rigid Wall ModelFor a given flow rate, the flow resistance is defined as the pressure drop required to drive the flow along the duct. This pressure drop generally includes viscous losses and any local flow separation or vortex loss.3.1.1 Equivalent diameter and lengthIt is assumed that the common bile duct and the common hepatic duct are straight tubes and join at a T-junction (Fig. 2). To model the effects of the cystic duct baffles on the flow, following Ooi et al [25], the baffles are arranged in the simplified manner, shown in Fig. 4. Unlike in the straight tube, the flow in the cystic duct needs to negotiate its way around the baffles and the worst scenario is shown by the arrow in Fig. 4. Thus the key problem is to estimate the equivalent length L eq , and the equivalent diameter, d eq , treating the cystic duct as an “equivalent straight pipe”. Once this is done, it is straightforward to calculate the pressure drop in the cystic duct assuming Poiseuille flow.The equivalent diameter for the cystic duct, CD d , is dependent on the number of baffles, as well as the baffle height. From Fig. 4 we can see that the bile flow travels twice the distance from points 1 to 2 between any two baffles in the duct, and 1A and 2A are the corresponding cross-sectional areas at points 1 and 2. The sector area 1A can be easily calculated from)212CD CD A d H d θ=− , (1)where θ is half of the centre angle of the baffle cut, and is written as))))11tan 22tan CDCD H d H d θππ−−⎧−⎪⎪=⎨⎪+−⎪⎩222CD CD CD H d H d H d >=< , (2)for a given tube with fixed values of CD L and CD d , 1A depends on the baffle height H only.The maximum diameter of the flow passage is equal to the diameter of cystic duct CD d without baffles, i.e.,max eq CD d d = , (3)It is shown in the Appendix that for the range of parameters in which we are interested, 1A is always smaller than 2A. Therefore the minimum diameter of the flow passage is associated with 1A , i.e.,min eq d = , (4)We now assume that the equivalent diameter of cystic duct varies linearly with the number of baffles between min ,eq d and max ,eq d , i.e.(),min ,max ,min 1eq eq eq eq c n d d d d n ⎛⎞=+−−⎜⎟⎝⎠, (5)where n c is the maximum number of baffles considered. For the parameters we considered, n c =18 (for details, see Appendix).The equivalent length of the cystic duct is determined from the actual length of the flow passage along the duct plus an extra length due to the complicated flow pattern, i.e.()1eq CD m L H n L L =−++, (6)where m L denotes the extra length corresponding to the minor pressure drop due to local vortices from the cross-section area expansion, contraction and the flow path bending in the baffle zone. It can be estimated from [28] that4128eq mm d p L QπμΔ=, (7) where m p Δ is the local pressure drop predicted by Bober and Kenyon [29], i.e.()2212324241616(1)m eq eqQ Q p n c c c n d d ρρππΔ=++− . (8)Here the sudden contraction head-loss coefficient is 110.42(1)CD c A A =−, and the sudden expansion head-loss coefficient is ()2211CD c A A =− [28]. The coefficient 3c is the head-lossdue to the flow bending around the baffles and it is a function of the bending angle. For a 90o bend, 3c has been measured to be 0.75 [29]. In our model, the angle through which the flowbends around a baffle should largely depend on the baffle height ratio, ξ, and to a lesser extent, on the number of baffles too. For simplicity, however, we assume that the angle is a linear function of ξ: 3c k ξ=, where k is chosen to be 0.85. Thus, for ξ=0 (straight tubeflow), 3c =0, and for ξ = 0.9, where 3D simulations typically show that the flow turningthrough 90o around the baffles, 3c =0.75.3.1.2 The Emptying PhaseThe pressure drop in the cystic duct in the emptying phase for a given number of baffles can now be estimated for Poiseuille flow [28]4128CD eq eqQ p L d μπΔ= . (9) For the common bile duct, in the emptying phase, the pressure drop can be written as4128CBD CBD te CBDQ p L p d μπΔ=+Δ , (10) where te p Δ accounts for the pressure drop owing to the T-junction which consists of one 90o bend and one expansion, given224224241616te CD CDQ Q p c c d d ρρππΔ=+ , (11) The coefficients 4c =0.75 for 90o bend and 2c may be treated in the same manner as those for Eq. (8). Thus the total pressure drop in the biliary system during the emptying phase is44128128EM eq CBD te eq CBDQ Q p L L p d d μμππΔ=++Δ . (12)3.1.3 The Refilling PhaseLikewise, during refilling, the pressure drop in the common bile duct is expressed by Eq. (10), and the pressure drop in the common hepatic duct is4128CHD CHD th CHDQ p L p d μπΔ=+Δ , (13) where224124241616th CHD CHD Q Q p c c d d ρρππΔ=+ , (14) and the total pressure drop during refilling is44128128RF eq CHD th eq CHDQ Q p L L p d d μμππΔ=++Δ . (15)3.2 The Elastic Wall ModelIn order to obtain a more realistic description for the pressure drop in the human biliarysystem, an elastic wall model is now considered. In reality, the ducts are soft tissues made of non-linear material, i.e. the Young’s modulus varies with the internal pressure [30, 31]. However, in the first instance, it is assumed that the cystic duct is a linear, isotropic elastic material with a uniform wall thickness. The hepatic and common bile ducts are still assumed to be rigid for two reasons: one is that the Young’s modulus of these ducts is greater than that of the cystic duct [30]; the other is that the pressure variations in these two ducts are much smaller (less than 1 Pa) than in the cystic duct and, therefore, the deformation of the ducts is also much smaller.For simplicity, we model the elastic behavior of the cystic duct as an “equivalent pipe” with an equivalent length L=L eq , and a diameter d eq . In other words, the effects of baffles on the flow come implicitly through L eq and d eq (or area A eq , which varies with the transmuralpressure, i.e. internal minus external). We assume that the cystic duct is initially circular and the duodenal valve opens during emptying, which reduces the pressure in the common bile duct. This, together with the rise in the gallbladder pressure, will initiate the bile flow out of the gallbladder, which further decreases the pressure downstream in the cystic duct. Thus the transmural pressure in the downstream part of the cystic duct during emptying will become negative. As a result, the cystic duct becomes partially collapsed towards the downstream end. This fluid-structure behavior is modeled following well-known work on collapsible flows [32,33, 34].3.2.1 The elastic wall modelThe Emptying Phase The partially collapsed cystic duct is shown schematically in Fig. 5, where p e is the external pressure, and equals to the pressure in the chest, e p =1.5kPa [4](above atmospheric pressure ). We introduce a one-dimensional coordinate system originating from point ‘O’. As the bile flows down the cystic duct, the internal pressure decreases due to viscous losses, causing a decrease in transmural pressure, e p p −, from the inlet (in A ) to theoutlet (out A ). The governing equations for the flow in the elastic cystic duct are [32]Au Q = , (16)28du dp Q u dx dx Aπμρ=−− . (17) The pressure at the inlet is chosen as the reference pressure. For a given flow rate, the corresponding pressure in the duct is derived by integrating Eq. (17)2222011118'(')2xin in p p Q dx Q A x A A πμρ⎛⎞=−+−⎜⎟⎝⎠∫. (18) The constitutive equation for the duct with an elastic wall obeys the ‘tube law’ forhomogeneous elastic materials [33],()αF K p p p e =− , (19)where()323121p Eh K rσ=− , (20) and 0A A α=, ()αF is usually determined by experiments. For veins, the tube law can be expressed as [32, 34]()1032F ααα−=−. (21)Since there is no experimental data for the cystic duct, here we assume that it obeys Eq. (21). The fluid pressure estimated using Eq.(19) is ()3231032232121e Eh p p Aπαασ−=+−⎡⎤⎣⎦− . (22) Combining Eq.(18) and Eq.(22), we have()3321032222321111821210in e in x Eh p Q dx Q p A A A A ππμραασ−⎛⎞′⎡⎤−+−=+−⎜⎟⎣⎦−⎝⎠∫, (23) Equation (23) represents a one-dimensional boundary value problem, which is solved using a finite difference method. The duct is divided into J elements (J is chosen to be > 300); a typical element extending from node j to j+1 is illustrated in Fig. 5. At the (j+1)th node, ()1032323112222232121001111182121j j j j e j j j j A A Eh p Q Q x p A A A A A A πρπμσ−+++++⎡⎤⎛⎞⎛⎞⎛⎞⎛⎞+−−Δ=+−⎢⎥⎜⎟⎜⎟⎜⎟⎜⎟⎜⎟−⎝⎠⎢⎥⎝⎠⎝⎠⎝⎠⎣⎦, (24) where222202221212122212111118,21111,211118,2j x j in in j j jj j j j j j j p p Q dx Q A A A A A A p p Q Q x A A A πμρρπμ+++++⎛⎞=−+−⎜⎟⎜⎟⎝⎠⎛⎞⎛⎞=+⎜⎟⎜⎟⎜⎟⎝⎠⎝⎠⎛⎞⎛⎞=+−−Δ⎜⎟⎜⎟⎜⎟⎝⎠⎝⎠∫and j p is known. Expressing ()2121j A + in terms of A j and A j+1, Eq. (24) can also be written as ()10323231122222232110011111142121j j j j e j j j j j A A Eh p Q Q x p A A A A A A A πρπμσ−+++++⎡⎤⎛⎞⎛⎞⎛⎞⎛⎞+−−+Δ=+−⎢⎥⎜⎟⎜⎟⎜⎟⎜⎟⎜⎟⎜⎟−⎢⎥⎝⎠⎝⎠⎝⎠⎝⎠⎣⎦. (25) We employ the bisection method to solve Eq.(25) to find unknown 1j A + in region[]1000.1,2j A A A +∈ in an iterative manner.The boundary conditions are applied at the inlet (node 1) ()()0331032232121in in in e in in in A A Eh p p A απαασ−=⎧⎪⎨=+−⎪−⎩, (26) If in α=1, then in e p p =; else if 1in α>, then in e p p >. The maximum pressure drop in the cysticduct is thus CD in out p p p Δ=−, and the total pressure drop occurring during emptying is4128EM CD CBD te CBDQ p p L p d μπΔ=Δ++Δ . (27) The Refilling Phase Because the bile flow rate is very small during refilling and the refill time is at least 3 times longer than the emptying time, the cystic duct wall can be regarded asrigid during this phase. Equations (13)-(15) in the rigid model are applied to calculate the pressure drop.4 Results and Discussion4.1 ParametersThe parameters used in the models are listed in Table 1. Most of these are taken from the statistics of human ducts given by Deenitchin et al [18]. The range of values for ξ, n and CD d are chosen to be the same as in the 3D models by Ooi [25]. The gallbladder flow rate isderived from the volume-time curve in Fig. 3, which lies between 0.49 and 1.23 ml/min. The range of the Young’s modulus used for this model is based on the measurements of [30], where bile ducts from 16 healthy adult dogs were tested with a pressure ranging from 4.7kPa to 8kPa. In fact, the physiological internal pressure is normally around 1.5kPa in the human biliary system, which is outside the pressure range used by Jian and Wang [30]. In order to obtain meaningful results, we estimate the Young’s modulus for the pressure around 1.5kPa from the extrapolation of the best curve fitting from the data of [30]. The Young’s modulus chosen for the models is therefore in the range of 100Pa and 1000Pa, which corresponds to the internal pressure varying from 1.03kPa to 1.9kPa.4.2 One-Dimensional Model ValidationAs several assumptions are used in deriving the equivalent diameter and length of the one-dimensional (1D) model, here we compare our 1D model with the three-dimensional (3D) rigid cystic duct models solved with the numerical methods. Fig. 6 illustrates the pressure drop variations with Reynolds number using the rigid model for the cystic duct only, with and without baffles. The geometry and bile parameters are CD L =50mm, CD d =5mm, n =0, 2, 6,10and 14, b h h ==1mm, ρ=1000kg/m 3, ν=1mm 2/s, respectively. These results are comparedwith the corresponding 3D cystic duct CFD results provided by [25], which was quantitatively validated by experiments [26] for higher Reynolds numbers. It can be seen that the agreement between the rigid model and 3D CFD results is consistently good for all values of parameters. This suggests that we have captured the main features of the flow in the rigid cystic duct. Theelastic model is derived for a straight pipe with equivalent diameter and length to the duct with baffles, and is based on the experimental curve for a straight rubber tube [32]. Therefore, if the rigid model with the correct equivalent diameter and length is accepted as satisfactory, then the elastic model is likely to be satisfactory.4.3 Pressure Drop for the Reference Parameter SetThere are many parameters present in the model, and each can vary within its ownphysiological range. In order to isolate the effect of each individual parameter, we introduce a Reference Parameter Set (henceforth referred to as the Reference Set), which is based on averaged values of a normal human cystic duct. The Reference Set is: n =7, ξ=0.5, ν=1.275 mm 2/s, CD d =1 mm, CD L =40 mm, E =300 Pa, in α=1, and Q =1 ml/min. The effect of anyparticular parameter on the pressure drop is determined by varying this parameter while keeping all the other parameters fixed. For the rigid tube, all parameters are the same except that Young’s modulus does apply.The predicted pressure drops in the human biliary system for the Reference Set using the rigid and elastic models in the emptying and refill phases are shown in Fig. 7. Two cases are considered: in α =1 and 1.2. in α =1 is the case when the inlet of the cystic duct is notexpanded, while in α=1.2 indicates a duct expansion because this has been observed clinically.It can be seen that for in α=1 the elastic model predicts a greater pressure drop in the emptyingphase, due to the collapse of the cystic duct. It is also noted that the maximum value of the pressure drop agrees with the typical physiological observation of 20Pa to 100Pa [4, 35].The ratio of total pressure drop in the common bile duct or common hepatic duct to the total pressure drop in the cystic duct, can illustrate the importance of the pressure drop across the cystic duct in the human biliary system. The results demonstrate that the pressure drop in the common duct is less than 1.5%, and in the common hepatic duct less than 0.15% only, compared to that in the cystic duct. This justifies estimating the pressure drop in the human biliary system from the cystic duct model only, as was done by Ooi et al [25].。

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J Cult Econ(2014)38:43–70DOI10.1007/s10824-012-9194-2O R I G I N A L A R T I C L EEvaluating the efﬁciency of public procurementcontracts for cultural heritage conservation worksin ItalyCalogero Guccio•Giacomo Pignataro•Ilde RizzoReceived:20July2011/Accepted:7November2012/Published online:21November2012ÓSpringer Science+Business Media New York2012Abstract Almost everywhere public intervention in cultural heritage(CH)con-servation is ing Italy as a case study,the paper analyses public capital expenditure for CH conservation and investigates whether the high degree of specialization of contracting authorities affects the efﬁciency of CH conservation works.A two-stage analysis is carried out.At aﬁrst stage,a nonparametric approach (Data Envelopment Analysis—DEA)investigates the relative efﬁciency scored by each single work;at a second stage,the determinant factors of the scores variability are investigated.The empirical analysis shows that,ceteris paribus,the expertise affects the efﬁciency of CH works.Keywords Cultural heritageÁConservationÁProcurementÁCost overrunsÁDelaysÁDEAJEL Classiﬁcation H57ÁD24ÁZ11IntroductionIn several countries,government intervention in cultural heritage(CH)conservation is widespread.One of the most relevantﬁelds of intervention is represented by public works for the conservation of CH,such as,for instance,CH restoration or maintenance as well as archaeological excavations,which are crucial for the conservation and the enhancement of CH.Though it is increasingly recognized that heritage is a strategic factor in the promotion of local development and that its economic impact is affected by the efﬁciency and effectiveness of public policies C.Guccio(&)ÁG.PignataroÁI.RizzoDepartment of Economics and Business,University of Catania,Corso Italia,55,95121Catania,Italye-mail:guccio@unict.it(Peacock and Rizzo2008),no much attention has been devoted to the analysis of how efﬁcient is the public sector in carrying out works in CH conservation.1At the best of our knowledge,this paper can be considered one of theﬁrst attempts to investigate the economic features of public works for the CH conservation.2 The analysis of the efﬁciency of CH conservation works raises some interesting theoretical issues,which can be of general interest for all public works.They are mainly related to the peculiar features of the decision-making process in thisﬁeld, especially as far as the crucial role played by experts is concerned(Peacock and Rizzo2008).It is claimed that conservation decisions are not neutral and that the outcome of decision-making process is crucially affected by experts(art historian, architect,archaeologist,urban planner);they enjoy an informative advantage,and, for this reason,they should play a crucial role in the decision on which type of conservation has to be carried out in each speciﬁc case and how.Experts’decisions, however,are highly subjective:a good example is offered by the debate on the adoption of standards for conservation,showing how difﬁcult it is toﬁnd an agreement among the specialists,on this topic.3More generally,experts are highly motivated by enhancing their reputation among their peers(Finocchiaro Castro and Rizzo2009):restorations of buildings,archaeological excavations or any other conservation activity offer a way to witness their expertise and may allow them to gain professional prestige and reputation.We are therefore interested in investigating whether the professional character-ization of decision-making process affects the efﬁciency of CH conservation public works.In this paper,we examine the efﬁciency of the execution stage with a focus on the implementation of contracts.Therefore,we will not consider the efﬁciency of the choices about what is to be conserved nor the outcome of CH conservation works.The efﬁcient execution of CH contracts has important economic implications on the realization of the relevant economic potentialities of CH in fostering sustainable economic development.Urban policies increasingly rely on the rehabilitation of CH to support economic activities and the services related to culture and tourism.At the same time,it has been stressed(Rizzo and Throsby 2006)that to be input of economic development,CH has to be the output of conservation policies,and therefore,the way how these policies are designed and implemented crucially affects the overall economic impact of CH.In line with the main conclusions reached in the literature,the efﬁciency of contracts execution will be expressed in terms of the capacity to complete the works within the costs and time agreed on in the contract.The analysis of the efﬁciency of the execution of CH conservation contracts will be carried out,using Italy as a case study.The rich CH endowment of the country,the relevant size of CH in public ownership and the extensive role of the public sector make Italy an interesting example to be analysed.Employing a detailed data set on Italian public contracts for 1A possible explanation is that public spending for CH conservation represents a very small share of GDP.Data on total public spending for culture are provided by OECD(2006)and Klamer et al.(2006). 2The performance of CH works,as compared to the rest of public works,has been investigated,with a different approach,by Guccio and Rizzo(2013).3For instance,see the Canadian Federal Heritage Buildings Review Ofﬁce(1996).CH conservation in the period2000–2005,the paper examines whether the characteristics of the decision-making process underlying CH conservation,for example the high degree of specialization of contracting authorities affect the efﬁcient management of the contract.To address such a question,a two-stage analysis is carried out.In aﬁrst stage,a nonparametric approach(DEA—Data Envelopment Analysis)is used to measure the relative efﬁciency in the implementation of each single contract.In the second stage,an empirical analysis of the determinant factors of the efﬁciency scores variability is carried out.The results of the empirical analysis show that,ceteris paribus,the expertise characterizing the CHﬁeld affects the performance of execution of CH contracts:specialized contracting authorities are,on average,less efﬁcient than the less specialized ones.They tend to pay more attention to the completion of the contract than to the control of theﬁnal cost.The performance of CH contracts,as measured by the efﬁciency scores,is mainly affected by the degree of specialization of the contracting authority and by the openness of the tendering procedure.This paper is organized as follows:in Sect.2,we brieﬂy describe the main institutional and economic features of the implementation of CH conservation in Italy.Section3investigates the concept of efﬁciency of execution of CH conservation contracts,and an appropriate methodological framework is provided in Sect.4.In Sect.5,we present our data set and provide technical efﬁciency estimates for CH conservation contracts in Italy.The analysis of the determinants of efﬁciency of execution in CH conservation is developed in Sect.6.Section7offers some concluding remarks.2Public intervention for cultural heritage conservation in Italy2.1Regulation of CH conservation worksThe CH conservation works,in Italy,are more heavily regulated than other public works.Their regulation,in fact,lies at the intersection of two set of rules,for example the Code of heritage(Codice dei beni culturali)and the Code for the award of public works(Codice dei contratti pubblici di lavori,servizi,forniture).The former contains the principles for the conservation and enhancement of heritage and the allocation of responsibilities between central and local governments,and it generally attributes a major role to the central government;the latter provides the rules governing the national procurement system,according to the principles set up in the EU Directive,with a speciﬁc reference to the CH conservationﬁeld.As far as public works in general are concerned,the law tries to reduce bureaucratic discretion:competition is promoted as much as possible,as a tool to select the most convenient bidder.To prevent opportunistic behaviour of private contractors,cost plus contract are not allowed.Moreover,to ensure the quality in the execution of works,access to the public works market is heavily regulated:ﬁrms need to be qualiﬁed according to a complex system referring to two criteria,type of works carried out in the past and theirﬁnancial size.An independent Authority(Autorita`di vigilanza sui contratti pubblici di lavori,servizi e forniture)supervises the functioning of the market for public works,the proper implementation of the existing regulation by the public authorities and the contractors as well as the functioning of the qualiﬁcation system for theﬁrms.4Within such a framework,CH conservationﬁeld is regulated with some speciﬁc provisions.The qualiﬁcation ofﬁrms entitled to enter the market is designed to ensure that they possess the speciﬁc expertise required by the restoration of heritage; the scope for restricted procedures to select theﬁrm is enlarged as well as the scope for the renegotiation of the contract.In other words,the idea that each conservation case is‘‘special’’seems to be taken into account by the rules,and more degrees of freedom are left to the negotiation between the contracting authority and theﬁrm at the execution stage,than in the general procurement case.2.2The characteristics of CH conservation public worksPublic contracts for CH conservation in Italy have a relevant size.Table1shows that in the period2000–2005,4,997public contracts above150,000euros were awarded,5(4.92%of the total number of public works contracts awarded in the same period)amounting to about3,545millions of euros(3.75%of the total amount of public works).Theseﬁgures represent the overall public demand for CH conservation.6On average,the size of CH conservation works is small(709.37 thousand euros),lower than the average size of total public works,7and it exhibits a high standard deviation.The public demand for CH conservation is fragmented in terms of the size of contracts.As Table2shows,3,363contracts(67.30%of the total number)are between150,000and500,000euros and,at the other extreme,only61contracts (1.22%)are between5million euros and15million euros,and only9contracts (0.18%)are above15millions of euros.Moreover,the contracts between150,000 and500,000euros represent25.03%of the total amount of money invested in CH conservation works in the period analysed,and those in the last two classes,above5 million euros,account for20.59%of the total amount.As far as contracting authorities are concerned,in the CH conservationﬁeld,8as well as in other sectors,municipalities play a major role in terms of the number of contracts awarded.Table3shows that54.91%of the CH contracts are awarded by 4A closer analysis of the Authority is provided by Rizzo(2008).5According to the estimates of the Autorita`di vigilanza sui contratti pubblici di lavori,servizi e forniture,almost64%refers to‘‘restoration’’while the others are classiﬁed as‘‘maintenance’’(24%),‘‘new intervention’’(8%)and‘‘others’’(5%).6Indeed,there might be an underestimation of the overall public demand for CH conservation for two reasons.On one hand,theﬁgures refer to theﬁnal stage of the tender,for example when the winner is chosen,while the number of the tenders just issued might be higher(but data are not available);on the other hand,the aboveﬁgures are based on the data which each contracting authority has communicated to the Authority,while it is likely that some of them do not fulﬁl the obligation on time.7The average size for the public works in general is931,705euros.8The49.39%of the overall public works contracts are awarded by municipalities and6.14by central government.local governments (municipalities)and 30.44%of the contacts are operated by central government,mainly through its specialized heritage authorities (Sop-rintendenze ),9run by experts and operating on a decentralized basis.10However,CH conservation works account for 24.37%of the total contracts awarded by centralTable 1CH conservation works awarded in the period 2000–2005SectorNumber of works Total amount Average amount SDMinMaxCH conservation works 4,9973,544,699709.371,704150.0152,678%of total works4.92 3.75Total public works awarded101,58994,651,035931.714,238150.00857,720Source :Authors’elaboration on data provided by Autorita `di vigilanza sui contratti pubblici di lavori,servizi e fornitureMonetary values in thousand euros at current pricesTable 2Number of CH conservation work per class of values in the period 2000–2005Classes of valueNumber of works%Total amount%Average amountCH conservation C 150.000€\500.000€3,36367.30887,23025.03263.82C 500.000€\1.000.000€86717.35612,05017.27705.95C 1.000.000€\5.000.000€69713.951,315,44137.111,887.29C 5.000.000€\15.000.000€61 1.22469,05813.237,689.48C 15.000.000€90.18260,9077.3628,989.71Total works 4,997100.003,544,699100.00709.37All public works C 150.000€\500.000€69,35168.2718,810,17219.87271.23C 500.000€\1.000.000€17,02016.7511,969,58412.65703.27C 1.000.000€\5.000.000€13,27113.0627,018,12028.542,035.88C 5.000.000€\15.000.000€1,387 1.3711,244,98311.888,107.41C 15.000.000€5600.5519,260,54520.3534,393.83Total contracts101,589100.0094,651,035100.00931.71Source :Authors’elaboration on data provided by Autorita `di vigilanza sui contratti pubblici di lavori,servizi e fornitureMonetary values in thousand euros at current prices9According to the reform of the organization of the Ministry of Cultural Heritage and Activities occurred in 2007(and revised in 2009),nowadays,the formal responsibility of being contracting authority pertains to the Regional Branches of cultural heritage and landscape (Direzioni Regionali per i beni culturali e paesaggistici ).Such a reform,however,does not apply to our analysis since our sample covers the period 2000–2005.Provveditorati are central government contracting authorities operating at interregional level on behalf of other public bodies.10Central government operates also through other contracting authorities,the Provveditorati ,acting at interregional level on behalf of other public bodies;however,their activity is of very limited size (only 57works in the period 2000–2005),and therefore,no speciﬁc attention will be paid to them in this paper.T a b l e 3C H c o n s e r v a t i o n w o r k s a w a r d e d b y c o n t r a c t i n g a u t h o r i t y i n t h e p e r i o d 2000–2005C o n t r a c t i n g a u t h o r i t y A l l s e c t o rC H i n t e r v e n t i o nT o t a l c o n t r a c t s%N u m b e r o f C H c o n t r a c t s%%o f t o t a l c o n t r a c t s T o t a l a m o u n t %A v e r a g e a m o u n tS DC e n t r a l g o v e r n m e n t 6,2416.141,52130.4424.37789,90226.546301,354o f w h i c h S o p r i n t e n d e n z e ––1,07521.51–620,17920.845761,529R e g i o n s a n d p r o v i n c e s 15,93515.6953510.713.36289,6109.73681844M u n i c i p a l i t i e s 50,17549.392,74454.915.471,647,59355.366871,661O t h e r s 29,23828.781973.940.67249,2918.381,3924,161T o t a l 101,589100.004,997100.004.922,976,397100.006991,749S o u r c e :A u t h o r s ’e l a b o r a t i o n o n d a t a p r o v i d e d b y A u t o r i t a `d i v i g i l a n z a s u i c o n t r a t t i p u b b l i c i d i l a v o r i ,s e r v i z i e f o r n i t u r eM o n e t a r y v a l u e s i n t h o u s a n d e u r o s a t c u r r e n t p r i c e sgovernment while,at local level,they account only for 5.47%.In other words,it seems that for central government contracting authorities,CH conservation can be considered a ‘‘core business’’,while for municipalities (as well as for other contracting authorities),CH conservation is just one the several ﬁelds of activity.Another indicator of the specialization of central government contracting authorities in the CH conservation ﬁeld,compared with other contracting authorities,is offered by the fact that 66.53%of the CH conservation works awarded by central government are based on in-house projects,while such a percentage is much lower,less than half,for the other contracting authorities (Table 4).11A further feature of the CH conservation market is that restricted procedures are more widespread than in the overall public works contracts market:Table 5shows that 27.64%of CH works are assigned through restricted procedures (accounting for 14.73%of the total amount of money invested in CH works)12while only 13.87%of the overall public works are assigned through restricted procedures,(i.e.6.40%of the total amount).These ﬁgures reﬂect the fact that the existing regulation provides more scope for restricted procedures in the CH conservation,the rationale being that these contracts,because of their highly specialized features,require a closer relationship between the experts in the contracting authorities and the supplier,leading to more degrees of freedom in the selection of the supplier.What are the effects of such a closer relationship and such a greater discretion on the efﬁciency of the CH contracts is an open question which will be investigated below.2.3The characteristics of the ﬁrms producing CH conservation public works The access to the public works market is heavily regulated.The ﬁrms must be qualiﬁed to participate to tenders above 150,000euros,and they can obtain theirTable 4In-house projects for CH conservation works awarded by contracting authority in the period 2000–2005Contracting authorityNumber of contracts%In-house project%%for each contracting authority Central government 1,25229.6083345.7966.53of which Soprintendenze 1,07525.4171939.5366.88Regions and provinces 42510.051417.7533.18Municipalities 2,39656.6480043.9833.39Others 157 3.7145 2.4728.66Total4,230100.001,819100.0043.00Source :Authors’elaboration on data provided by Autorita `di vigilanza sui contratti pubblici di lavori,servizi e forniture11Table 4reports a small difference in the overall number of contracts,4.252instead of 4.997since the information regarding the in-house project was not available for all the observations.12Restricted procedures are mainly concentrated in the contracts between 150,000and 500,000euros.qualiﬁcation certiﬁcate on the basis of their technical,economic and organizational features.13Namely,the qualiﬁcation is obtained,at a cost,for different categories (type of expertise)14and classes (ﬁnancial dimension).15The categories,which are relevant for the ﬁeld of CH conservation,are as follows:OG2Restoration and maintenance of built heritage ;OG4Underneath works of arts ;OS2Decorated surfaces and mobile heritage ;OS25Archaeological excavations.The supply in the market for public CH conservation works consists of 4,449ﬁrms,for example ﬁrms which are qualiﬁed for at least one of the categories OG2,0G4,OS2and OS25.Table 6shows that the qualiﬁcations obtained in the CH sector represent a small share of the overall qualiﬁcations,ranging from 3.58%(OG2)to 0.33%(OS25)16of the overall qualiﬁcations.As far as the classes (i.e.the ﬁnancial dimension)are concerned,the ﬁrms qualiﬁed in the conservation ﬁeld show different features,depending on the category.OG2exhibits a distribution similar to the overall set of ﬁrms:50%of the ﬁrms are concentrated in the two lowest classes and only a very small share in the two highest classes.Such a concentration in the lowest classes is even more marked for the specialized categories (OS2and OS25),showing that small ﬁrms prevail in these categories.Only OG4exhibits a high share in the two highest classes (32.32%),showing that big ﬁrms tend to prevail.Whether and how this feature of the supply affects the performance of the CH contracts is an open question which is addressed below.Table 5CH conservation contracts awarded in the period 2000–2005by tendering procedure Tendering procedure Number of contracts%Total amount%Average amountCH conservation Open 3,37567.542,901,09881.84859.59Restricted 1,38127.64521,96214.73377.96n.c.241 4.82121,638 3.43504.72Total 4,997100.003,544,699100.00709.37All public works contractsOpen 83,13181.8384,850,01289.651,020.68Restricted 14,08913.876,054,160 6.40429.71n.c.4,369 4.303,746,862 3.96857.60Total101,589100.0094,651,035100.00931.71Source :Authors’elaboration on data provided by Autorita `di vigilanza sui contratti pubblici di lavori,servizi e fornitureMonetary values in thousand euros at current prices13The system is run by private companies (Societa `Organismo di Attestazione —SOA );they evaluate whether each ﬁrm is entitled or not to obtain the required qualiﬁcation.14There are 13general categories,so called OG (such as roads,restoration and maintenance of built heritage,dams,underneath works of arts,railways,etc.)and 34specialized categories,so called OS (such as,decorated surfaces and mobile heritage,archaeological excavations,telecommunications infrastruc-tures,landscape,etc.).15There are 8classes ranging from 258,228up to 15,493,708euros.16These shares are higher if calculated within the general and the specialized sectors.3The measurement of efﬁciency in the execution of CH conservation contracts 3.1Cost overruns and delays in public work procurementIn general,the efﬁcient management of public works contracts can be measured alongside different aspects related to both the output of the work (e.g.the quality of the work,its capability of satisfying the objectives and the needs for which it has been carried out,etc.)and the process of the execution of the contract,which is instrumental to the realization of the output.We will focus on the latter issue.In the execution of public works contracts,two phenomena deserve attention:costs overruns and delays because they affect the efﬁcient execution of the contract (Guccio et al.2008)and have a potential negative impact on the social welfare generated by the realization of public works.These phenomena have been increasingly investigated in the literature and,in what follows;we try to offer a very brief overview of their relevance from the theoretical as well as the empirical point of view.Cost overruns are the additional costs incurred by contracting authorities above those agreed on in the contract.Guccio et al.(2012a )outline the several factors that have been considered as drivers of cost overruns,in the literature.First of all,when complex goods are procured,as it is the case for public works,there is an unavoidable degree of uncertainty related to events that may occur during the execution of the contract which may cause a difference between what is planned and what is actually realized,or needs to be realized.Cost overruns ‘‘therefore’’can be considered a consequence of the inadequate way of dealing with uncertainties in the planning stage,in terms,for instance,of poor initial design,which requires substantial changes in the execution stage,or of inaccuracy of costs forecasts.17Table 6Composition of supply by categories and classes—2005CategoriesNumber of qualiﬁcations%%of ﬁrms in the two lowest classes%of ﬁrms in the two highest classes Category OG22,956 3.5850.22 2.06Category OG43620.4425.4132.32All general categories 54,41165.8854.07 3.45Category OS24940.6071.260.20Category OS252750.3366.910.00All special categories 28,17934.1263.90 2.75All ﬁrms qualiﬁed in CH 4,449 5.3947.4711.37All qualiﬁed ﬁrms82,590100.0057.423.21Source :Authors’elaboration on data provided by Autorita `di vigilanza sui contratti pubblici di lavori,servizi e forniture17Ganuza (2007)provides a rational explanation for what could be regarded as underinvestment in project design.A higher investment on a more accurate initial design lowers the probability of renegotiation and of awarding the project to the most efﬁcient ﬁrm,but it increases its rents,when competition is not perfect.Indeed,in some cases,cost overruns are justiﬁed as consequence of unforeseen contingencies.18A second explanation provided for cost overruns refer to the concept of ‘‘optimism bias’’,for example a subjective will to underestimate costs,when designing the project(Flyvbjerg2005).Such an underestimation can depend on planning fallacy,leading to the overestimation of beneﬁts and the underestimation of costs(Lovallo and Kahneman2003)or it can be,instead,determined by the politicians’attitude to look for short-term political beneﬁts,as arising from the possibility of increasing the number of works to be started,even if,in the medium-to long-term,they will be delayed or even not completed because ofﬁnancial problems.A third relevant motivation offered for cost overruns is related to the potential opportunistic behaviour ofﬁrms,aimed at exploiting the contract incompleteness,to gain additional money over and above what has been agreed upon in the contract. Procurement features connected with the nature of the contract(ﬁxed-price vs cost plus contracts)and with the contract awarding procedure(auctions vs negotiations) may affect the strength of theﬁrms’incentives to behave opportunistically.As for the nature of contracts,with respect to the use ofﬁxed-price contracts,procurers face a trade-off between providing ex ante incentives and avoiding ex-post-transaction costs due to costly renegotiation:the costs arising fromﬁxed-price contracts,related to adaptation of projects,tend to be higher as the complexity of projects increases,since the potential for adaptation increases with complexity (Bajari and Tadelis2001;Estache et al.2009).As for the awarding procedure,in auctions,bidders may have an incentive to behave opportunistically;underbidding is a means to secure the win of the bid and,then,to exploit the opportunity of a renegotiation with incomplete contracts(Bajari et al.2009;Chong et al.2009; Guccio et al.2009).Delays refer to the excess time of completion of works with respect to the length agreed on in the contract.As De Carolis and Palumbo(2011)point out,several factors affect the occurrence of delays.Cost overruns and delays can be correlated: the presence of delays in the completion of a work may imply cost overruns,when the delay is representative of problems connected with the realization of the original project,and additional works are required.However,there can be delays without cost overruns.Moreover,delays are representative of other costs that are not included in cost overruns for the contracting authorities.Bajari and Lewis(2009, p.1)underline the relevance of completion time for social welfare and,referring to highways construction,suggest that slow completion times may generate‘‘signif-icant negative externalities for commuters through increased gridlock and commuting times’’.The time of completion can be extremely relevant in the CH case,especially when the intervention of conservation is carried out on artefacts which are in danger,and therefore,delays might even lead to their destruction. Therefore,delays may generate social costs and beneﬁts shortfalls,over and above the increase in costs for the contracting authorities.18This is the case,for instance,when changes in regulations,affecting the execution of public works, occur after the contract is signed or when unforeseen contingencies require technical changes.Cost overruns and delays thus are relevant phenomena affecting the efﬁcient execution of CH contracts.The efﬁciency of public spending for conservation(in terms of cost overruns and delays)says nothing about the quality of conservation that is whether this activity is properly carried out.The lack of a qualitative dimension is common to any analysis of the execution of public works because it is difﬁcult to standardize the production process,especially for complex works.The measurement of quality in CH conservation generates more severe problems:as it was pointed out before,conservation is not a well-deﬁned concept;experts may have professional disagreement on priorities about the extent and the type of intervention as well as on preservation strategies.There is wide agreement among experts that each piece of heritage is unique and that conservation should be carried out case-by-case,since real conservation cases require a mix of approaches and principles,able to grasp the mixed values of complex sites;the high variability of technical standards dealing with the same objects shows how difﬁcult is toﬁnd the specialists’agreement on this topic(Alca`ntara2002)and therefore stresses the subjectivity of qualitative judgments underlying conservation choices.As it was said above,cost overruns and delays are also empirically relevant in the execution of public works worldwide.Flyvbjerg et al.(2002)report that almost9 out of10projects experienced some cost overruns in transport infrastructure in20 developed and developing countries over the world,and Flyvbjerg(2005)estimates that the cost overrun of infrastructure caused by the delayed construction is at4.6% per year.Bajari et al.(2006)estimate that the economic costs of ex-post-adaptations account for about ten per cent of the winning bid for California highway contracts. For developing countries,Alexeeva et al.(2008)show that the value of a public road contract exceeds its engineering cost estimate by more than20%and that the average delay in project completion reaches10months.Iimi(2009)estimates that, for road procurement in Africa,about70%of contracts experienced some cost overruns,and adaptation cost is estimated at93cents per1dollar of contract adjustment.Cost overruns and delays are empirically very relevant also in Italy.Table7 shows the relevance of costs overruns and delays in the execution of public works completed in the period2000–2005,comparing CH conservation works with overall public ly,43.45%of CH conservation has experienced cost overruns above10%of the original cost.The results in terms of delays are even more striking:66.39%of CH conservation works involved a delay longer than20%of the completion time agreed upon in the contract.No major differences seem to occur between the CH conservation sector,and all public works contracts as far as delays are concerned.On the contrary,cost overruns are more severe for CH conservation works than for public works in general,a possible explanation being the above-mentioned differences in the regulation on the contract renegotiation.19 Thus,the data show that cost overruns and delays are relevant phenomena affecting the execution of CH contracts and are worth of investigation to understand the efﬁciency in the management of contracts for CH public works.19See above Sect.2.1.。

初二历史中国近代民族工业的发展试题答案及解析

初二历史中国近代民族工业的发展试题答案及解析1.面对民族危机，状元实业家张謇采取了实业救国的方案，创了著名企业A．中国实业银行B．启新洋灰公司C．福新面粉公司D．大生纱厂【答案】：D【解析】：此题考查近代民族工业的相关知识。

据题意，状元实业家张謇面对民族危机，采取实业救国，创办了著名的企业是大生纱厂。

选项中A、B、C不符合题意，C符合题意，故选C.【考点】人教版八年级上册·经济和社会生活·近代民族工业的发展2.1914年-1918年，中国民族资本主义得到发展的原因是（）A．日本给北洋军阀政府贷款B．北洋军阀分裂C．甲午战争后清政府改变政策D．"一战"时欧洲帝国主义无暇东顾，暂时放松对中国的经济掠夺【答案】D【解析】本题主要考查近代中国民族资本主义发展的原因，材料中“1914年-1918年”是解题的关键，据此可知当时处于一战中，回顾已学知识可知“一战”时欧洲帝国主义无暇东顾，暂时放松对中国的经济掠夺，故选D。

【考点】人教新课标八年级上册·中国近代民族工业的发展·一战时期中国民族资本主义发展的原因3.张謇放弃高官厚禄，回到家乡创办实业，但他的纱厂最终被吞并。

下列对此事的评述正确的是（）A．张謇舍本求末，他的失败毫不足惜B．张謇作为一个书生，不懂市场，失败是必然的C．在多重压榨之下，中国民族工业创办艰难D．“实业救国”的口号被实践证明是错误的【答案】C【解析】本题主要考查近代中国民族资本主义发展的相关内容，材料中重点强调的是近代中国民族资本主义发展的艰难曲折，联系已学知识可知近代中国民族资本主义在帝国主义、封建主义和官僚资本主义三座大山的夹缝中发展是比较缓慢和艰难，据此分析可知C符合题意。

【考点】人教新课标八年级上册·经济和社会生活·中国近代民族工业的发展4.近代中国民族工业发展过程中，涌现出荣氏兄弟的福新面粉公司、范旭东的大久精盐公司等一批民族企业。

35443341

与《文汇报》都放在国际新闻版的头条来处理，而且标题做得。很大，近乎通栏。更有甚者，如《闻晨报》不仅在头版作头新
。
／来看＝
，
当前媒体的舆论监督环境比以前更差了。如果说
之前的反舆论监督事件还主要表现在被监督主体的恶意诉讼以及某些地方政府的封杀、迫害的话，现在，反舆论监督主体正
同，共８个字）９，却将它放在第三版的右侧一串集束新闻中的第二位刊出，标题、字号都是平平淡淡，不显山露水，“ 美韩联合司令部新闻公报称（引题）美航母将不参加韩美联合军演
（题），只是向读者告知有这么一件事而已，不多去渲染。主 ”
这方是我们真正的立足点。站在此立足点上看《民Ｅ》的处理，我认为很好，很人ｌ报
条用标题新闻醒目刊出，而且在Ａ版上又作头条新闻刊出，４并冠以更醒目的标题《美军证实 “ 华蛊顿”号不参加军演》。
然而，“ 众人皆醉” ，唯它独醒，《民日报》当日同样登人
在逐渐呈现多样化趋势，手段越来越多，而且也越来越明日张
体放在眼里，很随意就对媒体采取行动。７月份，景德镇邮局的相关负责人居然为了当地订户看不到《西日报》对自己使江
兵不厌诈，打的都是政治牌。我们千万不要被美国一时的耀武扬威所吓倒，还是应贯彻毛泽东历来主张的 “ 战略上藐视它，

历史专业网站

历史专业网站1、史学研究网：/主要进行史学理论、史学史、海外中国学史方面的研究。

着重发布这一研究领域和研究方向的前沿学术成果和最新学术信息。

转载以往曾经发表过的有学术留存价值的史学信息和论文。

2、中国史学网：/主要面向高等院校历史专业教师、科研人员、研究生、本科生以及历史学爱好者，以促进高校历史专业本科教学为主，兼顾历史学研究和历史知识的普及，同时促进国内历史学界与境外和国际历史学界的网上学术交流。

3、中国读史网：/index.asp主要栏目有政坛风云、战火烽烟、文章中心、思想探微、史学论丛、国际纵横等栏目。

4、象牙塔：/中国社会科学院历史所陈爽博士的个人主页，有个人的研究成果及相关链接，其“国史论坛”颇有特色。

5、史学评论网：/cgi-bin/index.dll?index15? webid=jianwangzhan&userid=147978一个以促进中国史学评论发展、加强史学交流为主旨的史学类个人网站。

开设的栏目有：学术评论、史学评论、史书评论、史家研究、史学理论、学术史研究、研究综述、史学争鸣、史学讯息、文史博览、新书简介、池豫文集等。

6、历史风云网：/Index.html各个专题收集有思想文化科技、历史的奥秘、中外通史、历史故事、历史文化遗产等历史知识，而战争专题史、民主专题史、社会经济生活等栏目则体现了一定的学术性和专题性，并且收有中学历史的教材教参电子版以供下载。

7、中国世界古代史研究网：/系陈德正教授受中国世界古代史学会之托主持的非经营性网站，旨在通过互联网向上网用户无偿提供具有公开性、共享性的有关国内外世界古代史教学与研究的相关信息，主要受众为高校与科研院所的历史学及相关专业师生及世界古代史学的业余爱好者和研究者。

8、铜雀－中国历史网：/有中国通史、中国历代帝王、中国各朝疆域、中国历代名人等栏目，尤其是民族边疆史内容最佳，界面精美，资源相对比较丰富。

9、血铸中华：/由共青团中央和中国社科院主办。

新中国成立初期土地改革运动对乡村社会的影响

新中国成立初期土地改革运动对乡村社会的影响新中国成立初期的土地制度改革是一场由中国共产党发起的旨在实现“耕者有其田”与变革乡村社会秩序的革命。

这场革命解放了农业生产力，重组了乡村基层政治结构，引起了乡村社会阶级结构的变动，促进了乡村社会现代民主政治因素的生长，使得乡村社会经济、政治及文化上都发生了一系列深刻的变化。

乡村社会每天都在改造进步之中，每个人的生活也都处在发展变化之中。

新中国成立初期的土地改革运动不仅有效促进了当时中国乡村经济社会的发展，而且对当代中国乡村社会的变迁仍然有着深刻的影响。

标签：新中国成立初期;土地改革运动;中国乡村社会变迁新中国成立初期的土地改革运动不仅迅速实现了“耕者有其田”，而且带来了乡村社会前所未有的巨大变迁。

“对于中国几亿无地和少地的农民来说，这意味着站起来，打碎地主的枷锁，获得土地、牲畜、农具和房屋。

但它的意义远不止于此。

它还意味着破除迷信，学习科学;意味着扫除文盲，读书识字;意味着不再把妇女视为男人的财产，而建立男女平等关系;意味着废除委派村吏，代之以选举产生的乡村政权机构。

总之，它意味着进入一个新世界。

”①学界虽然在土地改革运动研究方面取得了不少成果，但从乡村社会变迁角度来研究土地改革运动的影响则尚有进一步深化拓展的空间。

本文试图从解决乡村社会的贫困与饥饿、增强农民群众对党和国家的政治认同、优化乡村社会的阶级结构、促进乡村社会现代民主政治因素的生长等方面，就土地改革运动对中国乡村社会的影响作些分析探讨，为新时期新一轮土地制度改革提供有益借鉴。

一、有效解决了乡村社会的贫困与饥饿由于西方列强的多次入侵和反动政府的残暴统治，近代中国乡村社会兵连祸结，灾荒不断，农业生产力遭到空前的浩劫和摧残。

据李约瑟统计，在近代史上，中国每6年就有一次农业破产，每12年就有一次大饥荒。

②在灾难的往复循环之中，农民的收入降低到不足以维持最低生活水平所需的程度。

在20世纪30年代，“年人均国民收入水平大约在58元（15美元）左右（按1933年价格计算），排名近于各国之末。

中华书局八年级历史上第六章测试题

17.19世纪70年代以后，一位京城的官员要与在上海的亲友取得及时联系可以选择的最佳手段有（） A．拍有线电报 B．写封书信 C．发无线电报 D．打长途电话 18.辛亥革命后，中国社会生活发生了巨大变化。假如你是一位已经接受新生事物并生活在当时的上海某政府官员，你不可能（）
A．坐轮船、火车去北京购买商品 B．向你的上司行跪拜礼、称“老爷” C．发电报问候亲人、与朋友照相 D．在报纸上看新闻、休闲时看电影
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1.与“状元实业家”、“大生纱厂”等关键词相关的人物是（） A.曾国藩 B.左宗棠 C.侯德榜 D. 张謇 2.毛泽东谈到中国民族工业时说：“提起中国民族工业，重工业不能忘记张之洞，轻工业不能忘记张謇”。毛泽东如此评价的原因是因为这两个人（） ①为中国工业建设做出了重大贡献 ②主张学习西方先进的科学技术 ③是民族资本家的杰出代表 ④是洋务派的重要代表人物 A. ①② B. ③④ C. ①③ D. ②④ 3. “民族工业的黄金时代在近代中国经济发展中占有特殊地位，是转瞬即逝的没有前途的经济奇迹。”材料中的的“黄金时代”主要发生在（） A.洋务运动期间 B.戊戌变法期间 C.第一次世界大战期间 D.解放战争期间 4.爱国主义是对自己祖国的一种最深厚的感情，不同历史时期，爱国主义有不同的内容。下列中国近代著名人物中提出“实业救国” 的是 ( ) A．康有为 B．荣宗敬 C．陈独秀 D．张謇
12.辛亥革命后，随着民主、平等思想的进一步传播，愚昧落后的社会习俗逐渐得到改变。下列体现这一改变的是（） A．称“老爷” B．行握手礼 C．缠足 D．行跪拜礼 13.在20世纪初的上海，人们可以做到的事是（） ①看《申报》 ②坐飞机 ③使用商务印书馆出版的字典 ④拍电报 A、①②③ B、①②④ C、①②③④ D、①③④ 14.有一歌谣唱道：“大脚好，大脚乐，去操作，多快活，又不裹来又不缠，又不疼痛又省钱”“大脚大，大脚大，阴天下雨我不怕；大脚好，大脚好，阴天下雨滑不倒。这一歌谣的流传最早应该是（） A．戊戌变法时期 B．辛亥革命后 C．新文化运动后 D．新中国成立后 15.我国开始使用电报应在（） A．19世纪60年代 B．19世纪70年代以后 C．19世纪末 D．20世纪初 16.右图反映的这一现象应出现在（） A．鸦片战争后 B．辛亥革命后 C．戊戌变法后 D．洋务运动后

河北初二初中历史期末考试带答案解析

河北初二初中历史期末考试班级:___________ 姓名：___________ 分数：___________一、选择题1.下图是1985年发行的《林则徐诞生二百周年》纪念邮票中的一枚，它反映的历史事件是（）A．虎门销烟B．火烧圆明园C．太平天国运动D．八国联军侵华2.标志着清政府完全成为西方列强统治中国工具的不平等条约是（）A．《南京条约》B．中俄《北京条约》C．《马关条约》D．《辛丑条约》3.中国近代史既是一部民族屈辱史又是一部民族抗争史，在抗击外来侵略、争取民族独立的艰难岁月中，涌现出许多可歌可泣的英雄人物。

其中为收复新疆、维护国家统一作出巨大贡献的历史人物是（）A．林则徐B．左宗棠C．邓世昌D．关天培4.义和团揭帖云：义和团，起山东，只因鬼子闹中原。

可见义和团兴起的原因之一是（）A．清政府的压迫B．列强的欺凌C．《马关条约》的签订D．知识分子的宣传组织5.在中国近代化道路探索过程中，资产阶级力图通过改革在中国发展资本主义的是（）A．新文化运动B．洋务运动C．维新变法运动D．辛亥革命6.近代中国面临着严重的民族危机，无数仁人志士都在探索救国救民的出路，下列选项搭配正确的是（）①林则徐、魏源——新文化运动②李鸿章、左宗棠——洋务运动③康有为、梁启超——戊戌变法④孙中山——辛亥革命A．①②③B．①③④C．②③④D．①②④7.下列有关辛亥革命的叙述中，正确的有（）①发生在1910年②推翻了清王朝③结束了中国两千多年的封建帝制④建立了中华民国A．①②③B．②③④C．①②④D．①③④8.《太行山上》、《血战台儿庄》、《狼牙山五壮士》等爱国主义教育影片，再现了中华民族坚强不屈的斗争历程。

这些影片取材的背景是（）A．北伐战争时期B．十年内战时期C．抗日战争时期D．解放战争时期9.新文化运动中激进民主主义者高举“民主”“科学”两面大旗，其中“科学”是指（）A．反对独裁专制B．反对迷信盲从C．反对旧文学D．反对旧道德10.上图是三大战役中以徐州为中心展开的哪个战役（）A．辽沈战役B．淮海战役C．平津战役D．渡江战役11.下列有关第一次国共合作的内容叙述不正确的是（）①两党第一次合作开始的标志是黄埔军校的建立②黄埔军校同一切旧式军校根本不同的地方是政治教育和军事训练并重③国民政府北伐的主要目的是统一全国，建立人民民主专政的国家④某影片中出现了“叶挺率领的第四军独立团正在猛攻武昌城”的镜头，这是再现北伐战争的战斗情景⑤第一次合作完全推翻了北洋军阀的统治A．①②⑤B．③④C．②④D．②③⑤12.中国近代第一所由国家建立的最高学府是（）A．福州船政学堂B．京师同文馆C．清华大学D．京师大学堂13.解放战争时期，人民解放军开始全国性战略进攻的标志是（）A．中共中央转战陕北B．晋冀鲁豫野战军跃进大别山C．淮海战役D．渡江战役14.红军被迫开始长征的原因是（）A．要以陕北为根据地B．要锻炼红军战士的意志C．临时中央负责人博古坚决主张D．第五次反“围剿”失败15.井冈山革命根据地的建立是（）A．中国共产党探索农村包围城市，武装夺取政权道路的开始B．中国共产党独立领导武装斗争的开始C．中国革命转危为安的关键D．中国共产党进行战略转移的开始16.鲁迅先生曾这样咏赞中国共产党诞生，“它是远方地平线上已经开的见桅杆的那一航轮船，是挣脱母腹的婴儿的第一声啼哭，是林中的响箭，是报春的惊雷。

Introduction1

Chapter 1: IntroductionRegional anaesthesia has increased in popularity in recent years (Clergue et al., 1999). This was prompted by two significant events. Firstly, the realisation that children do feel pain and require pain relief like adults; and secondly, that avoiding general anaesthesia in premature babies may have major advantages.With the increased survival of premature infants in recent years, the number of premature neonates presenting for surgery has increased. These premature neonates present with either chronic or acute defects that urgently need to be corrected. The risk of general anaesthesia is significant in these patients as they are at a greater risk of developing respiratory failure and postoperative apnoea compared to term infants of the same age (Welborn et al., 1986). Recent concerns regarding the deleterious effects of general anaesthesia on the developing brain further justifies the use of regional anaesthesia in this vulnerable age group (Sun et al. 2008).The use of regional anaesthesia therefore may have considerable advantages not only in premature neonates but also in infants, children and adults. The stages of development can be classified as follows: Stage 1: Neonate or newborn (0-30 days), Stage 2: Infant or baby (1 month-1 year), Stage 3: Toddler (1-4 years), Stage 4: Childhood (prepubescence) (4-12 years), Stage 5: Adolescence and puberty (12-20 years), and Stage 6: Adulthood (21 years - death), which can be subdivided into early adulthood (21-39 years), middle adulthood (40-59 years) and advanced adults/senior citizen (older than 60 years) (Jones, 1946).1.1) A brief history of paediatric regional anaesthesiaThe 19th century was a time when fundamental changes were made in the concepts regarding medicine. This is especially true for the speciality of regional anaesthesia. It is also the period regarded as the birth of modern regional anaesthesia (Bonica, 1984; Dalens, 1995). The thought that the heart is the centre for pain reception was discounted and Bell in 1811 andMagendie in 1822 showed that both motor and sensory impulses were relayed by the nerve tracts. By 1840, Muller established that the brain is the centre for perception and received all sensory information, including pain stimuli (Dalens, 1995).August Bier is commonly regarded as the “father of regional anaesthesia” and discovered the “cocainization of the spinal cord”, using a spinal anaesthetic technique (Fortuna & de Oliveira Fortuna, 2000). Since then, the regional anaesthetic techniques of the time included spinal, caudal epidural and supraclavicular brachial plexus blocks. These procedures gained enthusiastic acceptance by the anaesthesiologists of the time (Bainbridge, 1901; Farr, 1920; Campbell, 1933). However, these procedures gradually fell into disuse and almost came to a complete halt after the Second World War. This was mainly due to the development of new anaesthetic agents and improved techniques for general anaesthesia, which were safer and more reliable to use.The nineteen seventies saw a re-emergence of paediatric regional anaesthesia. Studies conducted by Lourey and McDonald (1973), Kay (1974) and Melman et al. (1975) caused a resurgence in the popularity of paediatric regional anaesthesia. The concept that regional and general anaesthesia can be used in a complimentary fashion, rather than being in contention with each other, also gained increasing acceptance (Dalens, 1995).This increase in regional anaesthesia could be attributed to the constant refinement, and/or development of new techniques. Research into newer, safer and better local anaesthetic solutions, as well as the use of continuous infusions through pumps, has offered new ways of providing pre- and post-operative analgesia to patients scheduled for paediatric surgery (Cook et al., 1995). With the above-mentioned advances in the field of anaesthesiology, the need for a strict protocol for administration, with reliable equipment, well-trained and alert personnel, become even more important (Fortuna & de Oliveira Fortuna, 2000).1.2) The importance of clinical anatomy in regional anaesthesiaDespite all the opportunities in medical research today, as well as the advances made in medical technology, the effective performance of clinical procedures still rests on a solid anatomical basis. This is even more important for medical practitioners in developing countries where technology is often lacking and they are dependent on their anatomical knowledge for the successful performance of clinical procedures (AACA, EAC, 1999).The practice of regional nerve blocks relies heavily on a sound knowledge of clinical anatomy (Winnie et al., 1975). This is especially true for anaesthesiologists who perform these blocks on paediatric patients (Bosenberg et al., 2002). Clinical procedures, such as regional nerve blocks, which either fail to achieve their objective or that result in complications, can often be linked to a lack of understanding, or even misunderstanding, of the anatomy relevant to the specific procedure (Ger, 1996; AACA, EAC, 1999).Winnie and co-workers (Winnie et al., 1973) states that no technique could truly be called simple, safe and consistent until the anatomy has been closely examined. This is quite apparent when looking at the literature where many anatomically based studies regarding regional techniques have resulted in the improvement of the technique, as well as the development of safer and more efficient methods. Anaesthesiologists performing these procedures should have a clear understanding of (a) the anatomy, (b) the influence of age and size, and (c) the potential complications and hazards of each procedure to ensure good results (Brown, 1985). Ellis and Feldman (1993) stated that anaesthesiologists required a particularly specialised knowledge of anatomy, which in some cases should even rival that of a surgeon. There is however a distinct lack of studies focusing on the anatomy of a paediatric population and relating it to a clinical setting (van Schoor et al., 2005). The anatomy described for paediatric patients are in most instances, obtained from adults and could be flawed (see Table 3.1 for an example).Performing regional anaesthetic procedures on paediatric patients have some additional complications and problems associated with it. Many anaesthesiologists may not be comfortable with working on a dose/weight basis. Most importantly, many anaesthesiologists not used to working with paediatric patients may lack the knowledge of the relative depths or position of certain key anatomical structures, as it is known that the anatomy of children of different ages may differ to a greater or lesser degree from that of adults (Bosenberg et al., 2002, Brown, 1985, Brown & Schulte-Steinberg, 1988, Katz, 1993). A thorough knowledge of the anatomy in children is therefore essential for successful nerve blocks and it cannot be substituted by probing the patient with a needle attached to a nerve stimulator, while the effective use of ultrasound requires a sound knowledge of the anatomy of the specific region. The anatomy described in adults is not always, and in most instances not applicable, to children of different ages as anatomical landmarks in children vary with growth. Bony landmarks (e.g. the greater trochanter of the femur) are poorly developed in infants prior to weight bearing. Muscular and tendinous landmarks commonly used in adults, tend to lack definition in young children partly because of poorer muscle development (Bosenberg et al., 2002), but also because they require patient cooperation to locate them. Most children are under sedation or general anaesthesia when the nerve block is being performed (Bosenberg et al., 2002, Armitage, 1985). Finally, classical anatomical landmarks may be absent or difficult to define in children with congenital deformities (Bosenberg et al., 2002).1.3) Indications and limitations of paediatric regional anaesthesiaRegional anaesthesia has advantages over general anaesthesia since it covers not only the intra-operative but also the postoperative period. Regional anaesthesia can be used to treat both acute and chronic pain and, in addition, it also provides both sympathetic and motor blockades (Saint-Maurice, 1995). Like all clinical procedures, the indications of regional anaesthetic techniques is based on well-established criteria, such as patient safety, quality of analgesia, duration of surgery, and whether it is a minor ormajor surgical procedure (Melman et al., 1975; Armitage, 1985; Saint-Maurice, 1995, Markakis, 2000, Wilder, 2000).Indications should not be decided by the subjective preferences of the anaesthesiologist or on the basis of mastery of the specific technique (although this is vital when the procedure is actually performed), but solely on whether the technique is required by careful examination of the indications (Saint-Maurice 1995). In order to select the best anaesthetic technique available, the benefits and risks of the regional nerve block should first be weighed against the advantages and disadvantages of all other available techniques of analgesia (Dalens & Mansoor, 1994).1.3.1 General indications of regional anaesthesiaPatients often have certain medical conditions, where the use of regional nerve blocks would be an advantage, these include:1.3.1.1 Disorders of the respiratory tractThe presence of respiratory diseases is in most cases (except the interscalene block, which has a high incidence of blocking the phrenic nerve) an indication for the use of regional anaesthesia. A regional nerve block can safely be performed on paediatric patients with respiratory distress, provided that the needle insertion, as well as the surgical site, is easily accessible. In certain cases, regional anaesthesia can be performed under mild general anaesthesia, after the patient has been intubated. In these situations, peripheral nerve blocks may be more preferable than central blocks. The advantages of combining both regional and general anaesthesia include reducing the requirements for intravenous and inhalational agents, thereby decreasing the risk of complications and also decreasing the recovery time. The patient should be extubated only when fully conscious and with the effect of anaesthetic inhalant worn off. This will allow the anaesthesiologist to effectively avoid aspiration (Saint-Maurice, 1995).1.3.1.2 Disorders of the central nervous systemThis is often considered to be a contraindication for performing regional nerve blocks. It is however more likely that an anaesthesiologist would refrain from performing regional nerve blocks on these patients more from the fact that there is a concern that the regional nerve block might worsen the disease state. The only true contraindications for performing regional nerve blocks on these patients are mechanical (neuropathy) and infectious conditions (infections in the vicinity of the block). Nevertheless, all children with disorders of the central nervous system should undergo careful evaluation before performing any regional nerve block on them. A neurologist should preferably do the evaluation and, as always, the risk versus benefit ratio should be carefully examined. (Saint-Maurice 1995)myastheniaand1.3.1.3 MyopathyRegional anaesthesia is especially indicated for patients with muscular dystrophy because it avoids the complications associated with general anaesthesia, particularly malignant hyperthermia. Unfortunately, due to the various anatomical deformities often found in these patients, certain regional nerve blocks might be more difficult to perform (Saint-Maurice 1995).1.3.2 General contraindications or limitations of regional anaesthesiaRegional anaesthesia has a very important place in children. Like any technique, it has its distinct advantages and specific indications. However, it also has limitations, disadvantages and contraindications that should be taken into account when performing regional blocks. Although contraindications are block dependant and should be known before attempting any regional nerveblock, general contraindications for regional anaesthesia include:1.3.2.1 Patient refusalPatient refusal is an absolute contraindication to regional anaesthesia. Appropriate information should be given to the patient regarding the technique, its advantages, disadvantages and potential complications. Informed consent must be obtained (Eledjam et al., 200).1.3.2.2 Local infections at the needle insertion siteSkin infections at the needle insertion site are an absolute contraindication to regional anaesthesia(Ecoffey & McIlvaine, 1991). This is also true for inflammation of the lymph nodes near the site of needle insertion.1.3.2.3 Septicaemia(presence of pathogens in the blood)1.3.2.4 Coagulation disordersCoagulation disorders, as well as patients who are undergoing antithrombotic or anticoagulant treatment are contraindications to a regional block because of the potential risk of haematoma formation (Dalens, 1995; Ecoffey & McIlvaine, 1991). Most of the complications have been described with epidural anaesthesia due to multiple traumatic vascular punctures and needle placement difficulties (Dalens, 1995).involving the peripheral nerves 1.3.2.5 Neurologicaldiseases(neuropathy)Although neuropathy (due to neurological or metabolic diseases) is not an absolute contraindication to perform a regional block, a clear benefit over general anaesthesia should be made (Ecoffey & McIlvaine, 1991).1.3.2.6 Allergy to the local anaesthetic solutionLess then 1% of all adverse reactions to local anaesthetics are due to patient allergy to the solution (Ramamurthi & Krane, 2007). Ester-linked local anaesthetics which are metabolized to para-amino benzoic acid (PABA) are far more likely to be associated with allergic reactions compared to amide local anaesthetics. Allergic reactions with amide local anaesthetics have yet to be reported in medical literature, although preservatives like methylparaben, present in many commercial preparations of amide local anaesthetics, are responsible for occasional allergic reactions (Naguib et al., 1998). Ester local anaesthetic allergies are true anaphylactic IgE-mediated allergies and not anaphylactoid reactions more commonly associated with other drugs used in the practice of anaesthesia (Ramamurthi & Krane, 2007).1.3.2.7 Lack of trainingAdequate skills regarding a specific technique are essential for a successful procedure to avoid complications and malpractice claims. Skills and expertise are key points to success in regional anaesthesia (Eledjam et al., 2000).1.4) Equipment used for paediatric regional anaesthesiaThe importance of selecting the appropriate devices and have them readily available when performing a regional block in children has long been underestimated and virtually all types of needles have been used for almost all types of block procedures (Dalens, 1999). Specifically designed needles and catheters are currently available for paediatric regional anaesthesia and it is now well established that a significant proportion of complications are directly related to the use of the wrong device (Giaufre et al., 1996). The importance of the correct equipment for a successful block was further confirmed in a survey of South African paediatric anaesthesia (van Schoor, 2004).Dalens (1999) stated that in addition to skin preparation solutions and sterile drapes to protect the site of puncture from bacterial contamination, the materials required to perform local or regional anaesthesia are rather simple but, nevertheless, specific. Sterile needles specifically designed to perform the relevant technique have to be used in children. He summarised the relevant equipment in a table (see Appendix A).An intravenous cannula should always be inserted in either the upper or lower limb in case of local anaesthetic toxicity caused by an accidental intravenous injection, or profound sympathetic blockade from a high epidural block. Light general anaesthesia is normally given to the paediatric patient. The procedure must be carried out with a strict aseptic technique. The skin should be thoroughly prepared and sterile gloves must be worn as infection in the caudal space is extremely serious (Jankovic & Wells, 2001).1.5) Imaging techniques used to aid in regional anaesthesia1.5.1 Nerve stimulators and regional anaesthesiaThe idea of stimulating a motor nerve in order to determine the ideal injection site for regional anaesthesia was first suggested by Von Perthes in 1912. Although, only within the past twenty years, have peripheral nerve stimulators (see Figure 1.1) become popular as clinical and teaching tools in regional anaesthesia practice (Visan et al., 2002). Nerve stimulators enable confirmation of the correct needle placement without inducing paraesthesia (Vloka et al., 1999) and, in turn, allow anaesthesiologists to perform the block in sedated or anaesthetised patients (Brown, 1993).Figure 1.1: Some commercially available peripheral nerve stimulators(Vloka et al., 1999).Since Pither et al. (1985) made recommendations on the use of nerve stimulators in regional anaesthesia; there has been an explosion of new and varied nerve stimulators available on the market. Although the advances in the technology surrounding nerve stimulators have made their use to localise the desired nerve(s) much easier, the wide variety of functions and features can be confusing for first-time users. This could in turn leave anaesthesiologists with an insufficient understanding of the basic principles behind nerve stimulation.principles of nerve stimulation1.5.1.1 BasicNerve stimulation techniques rely on the elicitation of appropriate motor responses to electrical current to confirm the proximity of the needle or catheter to the target nerve structure. Typically, nerve stimulation involves application of electrical current once the needle/catheter has penetrated the subcutaneous tissue, although surface mapping by transcutaneous electrical stimulation of peripheral nerves in children has been described (Bosenberg et al., 2002).The relationship between the strength and duration of the current and the polarity of the stimulus is of particular importance to nerve stimulation (Pither et al., 1985). To propagate a nerve impulse, a certain threshold level ofstimulus must be applied to the nerve. Below this threshold, no impulse ispropagated. Any increase of the stimulus above this threshold results in a corresponding increase in the intensity of the impulse (Tsui, 2007).It is also possible to estimate needle-to-nerve distance by using a stimulus of known intensity and pulse duration. A clear motor response achieved at 0.2 to 0.5 mA indicates an appropriate needle-to-nerve relationship. The tip of the needle is therefore close enough to the desired nerve to cause an effective block if the anaesthetic solution is administered. Nerve stimulation at <0.1 mA may indicate intraneural placement of the needle. This should be avoided as it may lead to nerve injury if the local anaesthetic is injected (Visan et al., 2002).Another important aspect to remember is that the cathode can be up to four times more effective at nerve depolarization than the anode, and thus it is the preferred stimulating electrode. Some problems may arise when nerve stimulators are not made to connect properly for other manufacturers’ stimulating needles and an adapter would therefore be required. It is best to use similarly manufactured stimulators and needles if possible (Tsui, 2007).A surface electrode is required to complete the electrical circuit and the optimal position to place the electrode on the patient’s body during peripheral nerve blocks is controversial (Tsui, 2007). According to Hadzic and co-workers (2004), this is less critical than was previously thought due to the introduction of constant-current nerve stimulators.features of nerve stimulators1.5.1.2 EssentialAccording to Visan et al. (2002), the essential features of the nerve stimulator include:•Constant current output: This assures automatic compensation for changes in tissue or connection impedance during nerve stimulation, inturn, assuring accurate delivery of the specified.•Current display: The ability to read the current being delivered is of utmost importance because the current intensity at which the nerve is stimulated gives the operator an approximation of the needle-to-nerve distance.•Current intensity control: Current can be controlled using either digital means or an analogue dial. Alternatively, current intensity can be controlled using a remote controller, such as a foot pedal, which allowsa single operator to perform the procedure and control the currentoutput (Hadzig & Vloka, 1996)•Short pulse width: Many peripheral nerve stimulators lack the ability for the user to control pulse width.•Stimulating frequency: Nerve stimulators with a 1 Hertz (Hz) stimulation frequency (1 pulse per second) are the norm. A model with a 2 Hz stimulation frequency may prove to be more clinically advantageous because it allows faster manipulation of the needle.•Malfunction indicator: This is a necessary feature because the operator should know when the stimulus is not being delivered because of malfunctions such as poor electrical connection and/or battery failure.A study conducted by Bosenberg (1995) revealed that a relatively cheap, unsheathed needle could be successfully used to locate peripheral nerves with the aid of a nerve stimulator in anaesthetised children. Although a slightly larger current is required to produce a motor response when compared to sheathed needles, a success rate of greater than 98% underlines its value as a cost-effective teaching tool, and the ease with which a technique can be mastered when using a nerve stimulator.Surface nerve mapping or transdermal nerve stimulation is a modification of the standard nerve stimulator technique and can be used to trace the path of a nerve prior to skin penetration. Surface nerve mapping could prove to be most useful in paediatric patients since anatomical landmarks are less precisely defined (Bosenberg et al., 2002), and paediatric patients are at the greatest risk for complications of regional anaesthesia.(Giaufre et al.,1996) Nerve mapping offers a further dimension for localisation of superficial peripheral nerves prior to skin penetration in both infants and children (Bosenberg et al.,2002).For locating superficial nerves, in patients of normal weight or paediatric patients, a special device can be used together with the nerve stimulator to trigger a transdermal response from the target muscle. The pulse duration of the device is set to 1 millisecond (ms) and the current range to 5 mA. In this way, it is possible to get a better fix on the puncture site or even correct the puncture direction. This also serves as an invaluable training tool for anaesthesiologists. Not only can the correct stimulus response be demonstrated but needle localisation and direction can be practiced before the needle is inserted (, 2009)Bosenberg and co-workers (2002) stated that peripheral nerve stimulation should not be a substitute for sound anatomical knowledge and careful technique. In a study, they did however show that using a nerve stimulator does provide a greater degree of reliability and accuracy in finding the correct needle insertion site, compared to using only anatomical landmarks or paraesthesias to perform nerve blocks. It is also a safer technique for attaining close proximity to the actual nerve.A combination of using a nerve stimulator/surface nerve mapping device and anatomical landmarks seem to be the best method for accurate, safe and successful blockade (Bosenberg, 1995).1.5.2 Ultrasound guidance and regional anaesthesia1.5.2.1 Advantages of ultrasound guidance during regional anaesthesiaThe use of ultrasound guided techniques for performing regional anaesthesia has greatly increased within the past decade. Recent studies show that ultrasound guided nerve blocks may have many advantages over traditional techniques. These studies reported less vascular puncture, highersuccess rates, and a reduced dose of local anaesthetic required in order to obtain a successful block (Marhofer et al., 2004; Sandhu et al., 2004; Bigeleisen, 2007).1.5.2.2 Basic principles of ultrasoundUltrasound machines can typically deliver sound waves of 2–15 MHz. Characteristically, the higher the frequency, the less the penetration depth but the better the resolution and vice versa. In the paediatric population, a high frequency linear probe is usually sufficient as the anatomy is much smaller and most structures being blocked are reasonably superficial. Sound waves propagate through the body and the amplitude of the reflected signals is based on different acoustic impedance of human tissue and fluids. Signals of least intensity appear dark (hypoechoic) or black as with body fluids, while signals of greatest intensity appear white (hyperechoic) as with bones and with intermediate intensities appearing as shades of gray. A common artefact is anisotropy, which is caused by an incidence angle of less than 90o between the probe and the structure being imaged. This results in poor or no reflection of the ultrasound beam from the tissue and, consequently, an inability to visualise it. The ultrasound beam must be oriented perpendicularly on the nerve axis to be able to visualise it (Marhofer et al. 2005; Brain et al., 2007).regional anaesthesia:1.5.2.3 UltrasoundguidedThe success of ultrasound guided nerve blocks relies on several aspects (Perlas & Chan, 2008):•Quality of image: This depends on the quality of the ultrasound machine and transducers, proper transducer selection (e.g., frequency) for each nerve location, sonographic anatomy knowledge pertinent to the block, and good hand-eye coordination to track needle movementduring advancement.•Patient position and technique: Optimal patient positioning and sterile technique is essential. This is particularly important for the continuouscatheter technique when it is necessary to use sterile conducting geland a sterile plastic sheath to fully cover the entire transducer.•Nerve stimulation: Nerve localisation by ultrasound can be combined with nerve stimulation. Both tools are valuable and complementary andnot mutually exclusive. Ultrasonography provides anatomical information, while a motor response to nerve stimulation provides functional information about the nerve in question.•Spread of anaesthetic solution: Ultrasound allows the anaesthesiologist to observe the spread of the local anaesthetic solution as well as real-time visual guidance to navigate the needle toward the target nerve.Two approaches are generally available to block peripheral nerves. The first approach aims to align and move the block needle inline with the long axis of the ultrasound transducer, so that the needle stays within the path of the ultrasound beam (see Figure 1.2a). In this manner, the needle shaft and tip can be clearly visualized. This approach is preferred when it is important to track the needle tip at all times (e.g., during a supraclavicular block to minimize inadvertent pleural puncture). The second approach places the needle perpendicular to the probe (see Figure 1.2b). In this case, the ultrasound image captures a transverse view of the needle, which is visible as a hyperechoic "dot" on the screen. Accurate moment-to-moment tracking of the needle tip location can be difficult, and needle tip position is often inferred indirectly by tissue movement. This approach is particularly useful for continuous catheter placement along the long axis of the nerve.。

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The Th La and Sm La conundrum of the Tethyan realm lamproites

The Th/La and Sm/La conundrum of the Tethyan realm lamproitesSimone Tommasini a ,⁎,Riccardo Avanzinelli a ,Sandro Conticelli a ,ba Dipartimento di Scienze della Terra,Universitàdegli Studi di Firenze,Via Giorgio La Pira 4,Firenze,I-50121,Italy bIstituto di Geoscienze e Georisorse,UnitàOperativa di Firenze,CNR,Via Giorgio La Pira 4,Firenze,I-50121,Italya b s t r a c ta r t i c l e i n f o Article history:Received 21May 2010Received in revised form 15October 2010Accepted 15November 2010Available online xxxx Editor:T.M.Harrison Keywords:Tethys oceans lamproitemantle metasomatism trace elementsradiogenic isotopes geodynamicsThe Oligocene –Pleistocene Tethyan Realm Lamproites,from the Mediterranean to Himalayas,have a clear subduction-related signature and represent one of the most exotic and rare ultrapotassic mantle-derived magmas.They share the major element and mineralogical characteristics of the lamproite clan rocks,but clearly de ﬁne a distinct subgroup with respect to within-plate lamproites on the basis of a number of key trace element ratios and radiogenic isotopes.The most striking characteristic of the Tethyan Realm Lamproites is the positive correlation between Th/La (up to N 1.5)and Sm/La (up to N 0.3),which is opposite to what observed in subduction-related magmas worldwide and cannot be reconciled with typical slab recycling processes.The geochemical conundrum of the Tethyan Realm Lamproites requires a component with high Sm/La and Th/La (hence named SALATHO),in addition to a normal K 2O –rich sediment melt component (with low Th/La and Sm/La).The Pb isotope composition of the Tethyan Realm Lamproites also displays a mixing array from a normal sediment melt component to a high 208Pb/206Pb and low 206Pb/204Pb end-member that can be reconciled with the SALATHO component.This end-member requires a history of high time-integrated κ(232Th/238U)and low time-integrated μ(238U/204Pb)and ought to be older than some hundreds of million years.We propose a multi-stage process for the formation of the mantle sources of the Tethyan Realm Lamproites related to the tectonic mélange domains (i.e.chaotic mixture of depleted peridotite,basalt,and sediment)accreted to the Eurasia plate during the collisional events of the northward drifting continental slivers from Gondwana.In a ﬁrst stage,the mélange domains experienced high P and low T metamorphism with segregation and stabilisation of lawsonite and zoisite/epidote veins,which potentially match the geochemical characteristics required by the SALATHO component.Successively,the subduction of the Neotethys and Alpine Tethys oceanic plates produced normal K 2O-rich sediment melts that migrated through the mantle wedge and metasomatised the depleted lithospheric mantle blocks within the chaotic mélange,forming a clinopyroxene –phlogopite vein network.Eventually,the Tertiary orogenic belt collapses triggered the onset of low-degree melting of the low-solidus fractions within the mélange domains,producing lamproitic magmas.©2010Elsevier B.V.All rights reserved.1.IntroductionIn ancient Greek mythology,Tethys (Τηθύς)was an archaic Titaness Sea Goddess,wife of the Sea God Oceanus,and mother of all the Oceanids.In the geologic literature too,Tethys is a sort of Mother of All Oceans prior to the Tertiary,and since its introduction in the 19th century (Suess,1893),is a well-established term to de ﬁne a series of ancient fossil ocean basins (Prototethys,Paleotethys,Neotethys,Alpine Tethys)separating the northern from the southern continents from Palaeozoic to Cenozoic (e.g.Gaetani et al.,2003;Scotese,2004;Stamp ﬂi,2000;Stamp ﬂi and Borel,2002;and references therein).The Tethyan oceanic lithospheric domains,originally present between Eurasia and Gondwana,have been subducted and partially obducted,and remnants of these former Tethyan ocean basins are found as ophiolites outcropping along multiple narrow suture zones from the Western Mediterranean to Himalayan orogenic belts.The general structure of the N 18,000km E –W striking Tethyan realm orogenic belts (Fig.1),from Morocco and Spain to India and Bhutan has been described in a wealth of studies since the pioneering work of Argand (1924).This array of inter-connected orogenic belts formed as a consequence of diachronous collisions of Gondwana-derived crustal plates rifted and northward drifted from the margin of Gondwana as three elongate continental slivers in the Silurian,Early Permian and Late Triassic –Late Jurassic.Earth and Planetary Science Letters xxx (2010)xxx –xxxEPSL-10670;No of Pages 10⁎Corresponding author.E-mail address:toms@uni ﬁ.it (S.Tommasini).Contents lists available at ScienceDirectEarth and Planetary Science Lettersj o u r n a l h o me p a g e :w w w.e l sev i e r.c om /l o c a t e /e p s l0012-821X/$–see front matter ©2010Elsevier B.V.All rights reserved.doi:10.1016/j.epsl.2010.11.023The prolonged subduction of the different Tethyan realm oceans along with the diachronous collision of the northward drifting continental slivers was accompanied by long-lived magmatic activity that is still active.The magmas produced represent one of the most impressive features of the geodynamic evolution of the Mediterra-nean –Himalayan orogenic belts,and are characterised by signi ﬁcant petrological,geochemical and isotopic variety ranging from subduction-related signatures with calc-alkaline,shoshonite and ultrapotassic magmas,to within-plate signatures with OIB-like magmas (e.g.Altherr et al.,2004,2008;Chung et al.,2005;Conticelli et al.,2009;Dilek and Altunkaynak,2007;Duggen et al.,2004;Gao et al.,2007;Harangi et al.,2006;Innocenti et al.,2005;Lustrino and Wilson,2007;Miller et al.,1999;Topuz et al.,2005;Turner et al.,1996;Williams et al.,2004;Wilson and Bianchini,1999).The Tethyan Realm Lamproites (TRL)represent minor and peculiar mantle-derived magmas of this widespread magmatic activity.They are ultrapotassic rocks extremely enriched in incompatible trace elements and formed by low-degree melting of depleted mantle sources metasomatised in subduction-related settings (e.g.Conticelli et al.,2007,2009;Foley,1992b;Peccerillo and Martinotti,2006;Prelevi ćand Foley,2007;Prelevi ćet al.,2005,2008;and references therein).This study is based upon a comprehensive database of the TRL –most of the Western Mediterranean lamproites are authors'data (Conticelli et al.,2009)–and other worldwide lamproites,and we focus the discussion on some key trace element ratios (Sm/La,Th/La)and Pb isotopes that so far have been overlooked and represent something of a paradox:the TRL are characterised by high and positively correlated Th/La and Sm/La along with high 208Pb/206Pb for a given 206Pb/204Pb.These unique geochemical and isotopic char-acteristics clearly separate the TRL from both within-plate lamproites and,most notably,subduction-related magmas worldwide.The geochemical and isotopic paradox demands for a common genetic process affecting the mantle sources of the TRL,related to the formation of the Tethyan realm orogenic belts as a consequence of diachronous collisions of Gondwana-derived crustal plates since the Palaeozoic.This scenario opens new insights into the origin of the mantle source of subduction-related lamproites and bears also consequences to the geodynamic evolution of the Western Mediter-ranean orogenic belts.2.Geochemical background 2.1.The ultrapotassic rock clanOn the basis of major element characteristics (Foley,1992a ),ultrapotassic volcanic rocks are classi ﬁed as lamproites (Group I),kamafugites (Group II),and plagioleucitites (Group III).Lamproites have low Al 2O 3,CaO and Na 2O contents,a silica range from 45to 55wt.%,and high Mg#[mol Mg/(Mg +Fe)]and K 2O/Al 2O 3.Kamafugites have also low Al 2O 3and Na 2O,but higher CaO and lower SiO 2than lamproites.Plagioleucitites have high Al 2O 3and Na 2O,coupled with low K 2O/Al 2O 3,and intermediate Mg#and CaO contents between lamproites and kamafugites.Experimental studies (e.g.Edgar,1987;Edgar and Vukadinovic,1992;Melzer and Foley,2000;Wendlandt and Eggler,1980a,b )demonstrated that different partial pressures of H 2O and CO 2along with different mantle sources (amphibole/phlogopite harzburgite vs .wehrlite)play a signi ﬁcant role in producing lamproite vs.kamafugite magmas.2.2.The Tethyan realm lamproites vs.within-plate lamproitesLamproites represent one of the most exotic and rare mantle-derived magmas.They occur in both within-plate and subduction-related settings (e.g.Bergman,1987).The TRL belong to the subduction-related subgroup (e.g.Conticelli and Peccerillo,1992;Conticelli et al.,2009;Gao et al.,2007;Miller et al.,1999;Prelevi ćand Foley,2007;Prelevi ćet al.,2005,2008;and references therein)and occur in a limited number of small-volume scattered outcrops of hypabyssal and volcanic rocks along the Tethyan realm orogenic belts from the Mediterranean to Southern Tibet (Fig.1).The gap from Turkey to Southern Tibet could simply represent sampling bias due to areas poorly investigated (e.g.Iran,Afghanistan).The TRL are invariably associated with calc-alkaline and shosho-nitic rocks.Their ages range from Oligocene (Western Alps,NW Vardar Zone),to Miocene (West Lhasa Terrane,Corsica,Murcia-Almeria,Western Anatolia),Mio-Pliocene (Southern Vardar Zone),and Plio-Pleistocene (Tuscany)(Table 1).Their petrological and geochemical characteristics,along with their association with other subduction-related magmas have been thoroughly discussed in a wealth of studies appropriately referenced by Conticelli et al.(2009),Gao et al.(2007),Fig.1.Shaded relief image of the Tethyan realm orogenic belts from Spain to Southern Tibet,showing the main outcropping areas of the Tethyan realm lamproites from west to east:(1)Murcia-Almeria,Spain;(2)Western Alps,Italy;(3)Corsica,France;(4)Tuscany,Italy;(5)Vardar Zone,Serbia and Macedonia;(6)Western Anatolia,Turkey;(7)West Lhasa Terrane,China.2S.Tommasini et al./Earth and Planetary Science Letters xxx (2010)xxx –xxxPeccerillo and Martinotti(2006),and Prelevićand Foley(2007).The TRL are SiO2-rich(45–55wt.%),high MgO(9–12wt.%)ultrapotassic rocks that share a number of mineralogical and major element characteristics with within-plate lamproites worldwide(e.g.Bergman, 1987;Foley,1992a).They are plagioclase-free rocks with high modal amount of phlogopite and forsteritic olivine,minor amount of Al-poor clinopyroxene and sanidine,and a number of accessory phases such as K-richterite,apatite,pseudobrookite,picroilmenite.The most maﬁc rocks have K2O N3wt.%,CaO b wt.%,Al2O3b12wt.%,and K2O/Na2O N2. Other common characteristics of all lamproites worldwide are(i)the high enrichment in incompatible trace elements(Table1),and(ii)the Sr,Nd,Pb isotope composition,which is among the most extreme of any mantle-derived magma(Fig.2,Table1).The low CaO,Na2O,and Al2O3contents along with the high-Fo olivine phenocrysts and associated Cr-rich spinel inclusions provide compelling evidence for derivation of lamproites from a depleted lithospheric mantle source,whilst the extreme incompatible trace element enrichment,along with the Sr and Nd isotope composition, requires re-fertilisation of the mantle source by K2O-rich metasomatic agents which permeated and reacted with the peridotitic mantle producing clinopyroxene/amphibole/phlogopite-rich veins(e.g.Edgar, 1987;Foley,1992b;Melzer and Foley,2000;Sekine and Wyllie,1982).The TRL have,however,a number of peculiar geochemical characteristics which make them unique in the lamproitic clan.First, they are clearly distinguished from within-plate lamproites worldwide (Western Australia,Leucite Hills,Smoky Butte,Gaussberg,Aldan Shield) on the basis of Sr-Nd(Fig.2)and Pb isotope compositions(Table1). Second,they have a clear subduction-related signature,exempliﬁed by highly radiogenic Sr isotopes(Fig.2),crust-like trace element patterns and High Field Strength Element depletion(Fig.3),which provide compelling evidence for a crustal component recycled into the mantle via subduction zones,as the K2O-rich metasomatic agent responsible for mantle re-fertilisation(e.g.Avanzinelli et al.,2009;Foley,1992b; Peccerillo and Martinotti,2006;Prelevićand Foley,2007;Prelevićet al.,2008).The wide range of87Sr/86Sr and143Nd/144Nd(Fig.2) indicates the involvement of crustal components of variable composition in the TRL mantle sources(Prelevićet al.,2005).Despite the crust-like patterns,highly incompatible trace elements(Rb,Ba,Th,and U,Fig.3) have on average different ratios with respect to present-day Upper Crust and Global Subducting Sediment(GLOSS,Plank and Langmuir,1998), and represent a distinctive signature of the TRL.Third,on Ba/Rb vs.Rb/Sr and K/Th vs.Th(Fig.4),the TRL form a separated group with respect to other lamproites.Their higher Rb/Sr coupled with lower Ba/Rb(Fig.4a) provides arguments for the major role of phlogopite in their mantle sources with respect to the major role of amphibole in the case of other lamproites.Also,the TRL have generally lower K/Th than other lamproites(Fig.4b):this is caused by the extreme Th enrichment,up to N200ppm(Table1),rather than lower K2O contents.Fourth,perhaps the most striking characteristic,they exhibit a positive correlation between Th/La and Sm/La(Fig.5).The high Th/La(up to N1.5)and Sm/La (up to N0.3)is caused by the combination of two factors:the extreme Th enrichment and the slightly concave downward LREE patterns(e.g. Conticelli et al.,2009)of the TRL.The extreme Th contents also result in abnormally high Th/U(Th/U N10,Table1),well beyond the Th/U≤4of most crust and mantle rocks(e.g.McDonough,1990;Plank and Langmuir,1998;Rudnick and Gao,2003;Sun and McDonough,1989). The Th/U N4is not unique to the TRL,being exhibited also by the Western Australia and Gaussberg lamproites(Table1);in the TRL,however, the high Th/U is coupled with high Th/Ta(Table1)reinforcing the subduction-related origin of the TRL and hence their different geodynamic setting with respect to within-plate lamproites.2.3.The Tethyan realm lamproites vs.subduction-related magmasThe positive correlation between Th/La and Sm/La does not simply distinguish the TRL from within-plate lamproites(Fig.5),it actually represents something of a paradox when compared to subduction-related magmas worldwide.Magmas produced by depleted mantle sources(i.e.high Sm/La and low Th/La)that have been enriched in trace elements via sediment recycling in subduction zones exhibit a negative correlation on Th/La vs.Sm/La(greyﬁeld,Fig.5),owing to the low Sm/La and relatively high Th/La(~0.3–0.5)of the sediment component metasomatising the mantle wedge(Plank,2005).In addition,modern volcanic arc magmas,as well as crustal rocks(Plank, 2005;Plank and Langmuir,1998;Rudnick and Gao,2003)have Th/ La≤0.5,whilst the TRL have extreme values of Th/La(Fig.5),which are not observed in any other mantle-derived magma.The negative correlation between Th/La and Sm/La in modern volcanic arcs is widely recognised as a key characteristic of arc magmas(Plank,2005). Depleted mantle sources metasomatised by low Tﬂuid-dominated components,form magmas lying at low Th/La and high Sm/La,whilst those metasomatised by high T melt-dominated components,form magmas with relatively high Th/La–but well below unity–and low Sm/La(greyﬁeld,Fig.5),resembling the subducted sediment composition.In each volcanic arc setting,the similarity between Th/ La of subducted sediments and erupted magmas suggests no signiﬁcant fractionation during slab and mantle melting(Plank, 2005).The K2O enrichment and other subduction-related characteristics of the TRL have been widely interpreted as related to recycling of sedimentary material into their depleted lithospheric mantle sources (Conticelli and Peccerillo,1992;Conticelli et al.,2007;Foley,1992b; Peccerillo and Martinotti,2006;Prelevićand Foley,2007;Prelevićet al.,2005,2008).However,it is important to point out that the high Sm/La(and Th/La)of the TRL is not correlated to their subduction signature and K2O enrichment(Fig.6),indicating the presence of a further metasomatic agent in the TRL mantle sources.3.The SALATHO componentAs a whole the TRL exhibit a positive mixing array from a normal crustal component to another component with high Sm/La and Th/La (hereafter SALATHO).Whilst the normal crustal component can be referred to typical K2O-rich sediment melts of subduction zones, decoding the SALATHO component is problematic and we shall discuss it in detail.To aﬁrst approximation the SALATHO component should also have a broad crustal origin.The West Lhasa,Spain, Western Alps,and Tuscan lamproites,in which the SALATHO com-ponent is most evident(Table1,Fig.5),have extremely radiogenic Sr isotopes(Fig.2)and trace element patterns similar to other TRL that are dominated by the normal sediment melt component(e.g.Western Anatolia and Corsica lamproites,Fig.3).We therefore discuss the SALATHO component as deriving from a protolith dominated by sedimentary lithologies.It is worth pointing out that although both components(SALATHO and K2O-rich sediment melts)are interpreted as sediment-derived,we shall see that they actually refer to two distinct and time-separated processes.In the following discussion we shall use present day GLOSS as a general proxy for sediments,due to the lack of detailed information on the composition of sediments deposited within each Tethyan realm ocean basin.Moreover,the use of speciﬁc sediment composition for each area would focus the discussion on local processes,in contrast with the common geo-chemical characteristics exhibited by the TRL(e.g.Fig.5),suggesting a genetic link between these magmas.The LREE and Th budget of slab-derived metasomatic agents delivered to the mantle wedge is controlled by accessory phases such as apatite,monazite,allanite(e.g.Hermann and Rubatto,2009;Klimm et al.,2008;Plank,2005;Skora and Blundy,2010).Apatite has D Sm N D La N D Th(e.g.Prowatke and Klemme,2006),meaning that any apatite in the sediment residue after dehydration/melting will determine the production of metasomatic agents with Th/La slightly higher and Sm/La lower than the starting material.This can3S.Tommasini et al./Earth and Planetary Science Letters xxx(2010)xxx–xxxpotentially determine the typical negative correlation between Th/La and Sm/La as commonly observed in volcanic arc magmas(greyﬁeld, Fig.5),but cannot account for the positive correlation exhibited by the TRL(Fig.5).The potential role of allanite and monazite has been assessed using a number of recent experimental studies on oceanic crust(basalt+ sediment)dehydration and melting at P-T conditions relevant to subarc regions,in which either allanite or monazite was present(orTable1Average composition of selected major and trace elements,radiogenic isotopes,and trace element ratios of the Tethyan realm lamproites and within-plate lamproites worldwide.NationLocalityOrogenic BeltAge SiO2Al2O3MgO CaO K2O P2O5Cr Ni Rb Sr Ba La SmTethyan realm lamproitesSpain Miocene Avg54.810.510.6 4.1 6.9 1.064945147067718738927.2 Murcia-Almeria1sd 3.4 1.6 3.5 2.1 1.80.316514522328765319 5.5 Betics Min44.87.3 3.5 2.4 3.40.63341503040211825917.4Max60.514.519.811.99.5 2.19417149031617433414340.2n33333333333333334141333341 Italy Oligocene Avg52.911.09.9 5.87.6 1.1564280433797372810229.8 Western Alps1sd 3.5 1.1 2.0 1.6 1.70.11898112815661630 6.8 Alps Min48.88.97.0 3.1 3.70.83099315853023085415.6Max61.713.513.68.49.8 1.49334606461242474016439.4n17171717171717171717151312 France Miocene Avg58.110.7 6.7 3.310.50.7422267340764119417217.7 Corsica1sd0.70.10.30.30.20.15631259219926 1.6 Alps Min56.710.5 6.4 2.910.20.634023031764092513516.3Max58.610.87.1 3.710.70.8530322376847145019319.1n7777777777774 Italy Pliocene Avg57.212.38.2 4.07.60.8502247580528117410423.7 Tuscany1sd 1.3 1.2 1.4 1.00.40.3858414613214336 3.8 Apennines Min55.310.6 4.2 2.27.00.5380923712367604618.4Max62.014.611.8 6.98.9 1.3672427874686140017329.0n3030303030301830303030309 Serbia&Macedonia Oligocene Avg49.811.88.97.3 5.2 1.148828423997521406713.7 Vardar Zone Mio-Pliocene1sd 3.1 1.5 2.0 1.6 1.40.42631409034299427 4.8 Dinarides min42.49.7 4.3 3.8 2.80.565457239441023 6.5Max60.115.313.49.97.4 1.911766535541712418913521.9n56565656565656565656565449 Turkey Miocene Avg49.110.610.18.1 6.6 1.46103532791516201710912.4 Western Anatolia1sd 2.3 1.3 2.2 1.80.80.313018012359765950 2.1 Taurides Min45.78.9 5.6 4.9 4.80.615949189476249438.6Max54.213.312.910.78.5 2.17925977262326324218816.4n25252525252521252525251514 China Miocene Avg55.412.8 6.1 5.77.3 1.0353191655942285113035.9 West Lhasa Terrane1sd 2.00.8 1.2 1.1 1.00.28054146262537307.8 Tibetan Plateau Min53.310.9 3.5 3.9 4.50.62398739162118637224.6Max60.714.310.27.18.6 1.45653589391633393120048.0n29292929292929292929292929 Worldwide within-plate lamproitesGaussberg Pleistocene Avg50.69.98.0 4.411.7 1.53072402891610507818114.91sd 1.00.30.40.20.40.1383840125298120.9Min48.79.47.1 4.111.0 1.42181541601355430215411.9Max52.410.48.8 4.712.5 1.63653393231816568620416.4n24242424242424242424242424 Leucite Hills Pleistocene Avg48.18.79.08.38.3 2.24431962493855753029225.11sd 4.70.9 1.8 3.4 2.20.5915458155520771149.3Min41.47.2 5.7 3.3 4.7 1.32661041301830447111912.8Max55.810.112.212.711.9 3.056033346072331250042139.1n40404040404040404040404033Australia OligoceneMiocene Avg51.37.411.7 6.08.3 1.17005503431350928026418.7 1sd 6.6 2.47.50.8 2.90.6129465393386 6.4 Min19054944001107.6 Max61423491810042529.3 n1515141515Smoky butte Oligocene Avg52.38.98.2 4.67.9 2.14953449627061127537437.3 1sd0.80.20.30.20.80.36534364434941 4.1Min51.48.67.8 4.4 6.5 1.6437502226870933232.6Max53.59.18.5 4.98.8 2.358314031502000043743.1n666666666666Aldan EarlyCretaceous Avg45.9 6.916.47.4 5.70.88263931921802382332 6.4 1sd 1.9 1.8 5.6 1.5 2.10.7443301801386367923 3.4 min42.4 4.67.3 4.2 2.90.3110738756112349 2.5 Max48.19.222.79.28.3 2.215159003144139127736812.9 n1010101010101091010101010Avg:average value,1sd:absolute standard deviation,Min:minimum value,Max:maximum value,n:number of samples.Data source:Altherr et al.(2004);Benito et al.(1999); Bergman(1987);Coban and Flower(2007);Conticelli et al.(2009);Cvetkovićet al.(2004);Davies et al.(2006);Ersoy and Helvaci(2007);Francalanci et al.(2000);Fraser et al. (1985);Gao et al.(2007);Innocenti et al.(2005);Miller et al.(1999);Mirnejad and Bell(2006);Mitchell et al.(1987);Murphy et al.(2002);Nelson et al.(1986);Owen(2008); Prelevićet al.(2004,2005,2008);Vollmer et al.(1984);and references therein.The complete lamproite clan database is available as supplementary material at doi:10.1016/j. epsl.2010.11.023.4S.Tommasini et al./Earth and Planetary Science Letters xxx(2010)xxx–xxxhas been inferred to be)as by-product(e.g.Hermann and Rubatto, 2009;Johnson and Plank,1999;Kessel et al.,2005;Klimm et al.,2008; Skora and Blundy,2010).In Figure7,the Th/La and Sm/La of each experimental run have been normalised to those of the starting materials to cancel out trace element doping,whilst the trace element ratios of the TRL have been normalised to those of GLOSS in order to make a reasonable comparison between experimental runs and real magmas.Although the latter normalisation might not be strictlyTa Th U87Sr143Nd206Pb207Pb208Pb Th/La Ba/Rb Rb/Sr K/Th Sm/La Th/U Th/Ta 86Sri144Ndi204Pbi204Pbi204Pbi2.86101.221.30.71840.5120318.7815.7239.11 1.1 5.20.795820.32 5.137.0 0.5921.6 5.70.00250.000020.050.020.080.1 6.90.411480.03 2.37.62.0364.08.50.71150.5119718.6615.6838.980.8 2.00.052550.263.423.83.95159.734.50.72260.5120718.8415.7839.30 1.539.2 1.469210.3815.353.5 313337333328282833334133333331 2.02142.525.50.71680.5120318.6215.6939.02 1.49.50.564510.31 5.668.90.3935.2 5.20.00240.000040.060.020.220.2 3.30.22980.03 1.016.91.4181.915.20.71210.5119918.5015.6738.76 1.0 5.50.243530.26 4.146.82.73226.033.60.72170.5121018.7215.7239.50 1.814.6 1.177280.358.1108.7 141716141212121213151717121614 3.5436.012.80.712370.5121518.8215.7039.310.2 3.50.4551970.116.18.4 0.5716.616.00.00020.050.010.020.10.60.0376070.01 4.0 5.13.004.3 4.30.712260.5121518.7915.6939.290.03 2.90.4015900.100.1 1.44.1053.036.80.712560.5121518.8515.7039.320.3 4.60.50207150.128.613.7 464322226776444 2.47102.214.90.71610.5121118.6615.6739.010.9 2.2 1.236840.23 5.739.3 0.3726.5 3.00.00040.000020.030.030.110.30.60.572470.05 1.413.92.0050.410.70.71580.5120918.6215.6438.900.50.90.575130.18 4.320.43.10121.018.20.71680.5121218.6915.6939.15 1.5 3.5 2.4612290.328.058.0 914711444414303014979 1.3236.37.30.70950.5123018.7615.6538.950.610.80.2813700.20 6.228.4 0.4714.6 3.80.00140.000120.080.140.130.28.60.186340.04 3.916.4 0.7715.0 1.90.70750.5121318.5815.1238.780.0 1.60.076110.13 2.511.0 3.0176.517.50.71160.5125218.8915.7439.240.938.4 1.4131320.2618.072.2 295555363631313154565655495529 5.4117.2 6.40.70670.512370.207.90.2233760.13 3.0 4.3 2.83 4.1 2.00.00250.000190.10 3.10.148620.050.9 3.1 1.2310.0 2.50.70380.512230.050.80.0918860.07 1.9 1.6 10.0028.010.00.71030.512500.4416.30.7054460.22 5.315.4 2425166215252525141624 2.78171.421.30.72350.5118818.6715.7439.67 1.4 4.60.753650.298.567.80.9434.2 5.00.00690.000060.170.050.150.4 1.50.26800.06 2.324.41.30112.09.60.71660.5118018.4115.6839.420.7 2.70.242740.15 4.633.44.54231.729.40.73630.5120018.9315.8440.06 2.28.8 1.145490.3813.7130.0 2929291918232323292929292929294.9923.2 3.20.70960.5119217.5015.6038.260.1318.00.1842450.0827.4 4.7 0.25 2.80.40.00020.000040.050.020.080.01 3.40.035730.004 1.00.64.4115.9 2.20.70920.5118717.4215.5738.150.1015.50.1033730.077 4.6 2.95.4228.3 3.80.70990.5120217.6115.6338.430.1529.70.2160560.0939.5 5.8 242424242424242424242424242424 5.0936.28.50.705700.5119517.3815.4837.350.1232.80.0825130.10 4.27.31.9612.9 2.80.00040.000110.140.010.140.0114.20.0420850.020.6 1.62.0013.7 3.40.705340.5117717.1815.4637.130.1110.20.029040.06 3.14.9 8.8148.011.40.707790.5121117.5815.5137.520.1570.40.1769680.17 5.210.8 161616484224242416404016331616 8.0832.9 4.10.71690.5118817.4415.7338.160.1129.90.2823920.0719.7 3.73.1019.1 2.90.00310.000130.160.030.320.0410.80.1416550.005 6.3 1.04.680.00.00.71100.5116617.2315.6837.200.0712.70.166870.064 2.6 2.5 15.9069.110.30.72060.5121017.8815.8038.590.2450.00.6562860.08131.56.0 152727151519191915141515152515 5.81 6.5 1.90.70610.5113816.2415.2236.390.017126.70.04103870.100 4.0 1.1 0.64 1.0 1.10.00020.000080.250.040.200.00150.10.0223790.001 1.10.15.08 5.3 1.10.70580.5112716.0315.1936.200.01673.90.0280770.098 1.8 1.06.797.8 4.00.70630.5115016.6415.2836.680.019191.00.05138720.101 4.8 1.2 666666666666666 0.40 4.0 1.70.70650.5116717.0615.3737.320.1422.50.17223210.24 2.612.3 0.43 3.6 1.60.00080.000220.320.090.140.0621.60.15251920.090.7 6.10.090.80.20.70550.5113516.6115.2437.130.03 5.40.0454810.15 1.9 4.81.4012.5 5.70.70790.5119317.4215.4737.500.2377.90.51845920.453.923.8 1010101010101010101010101010105S.Tommasini et al./Earth and Planetary Science Letters xxx(2010)xxx–xxxcorrect,any other crustal composition would yield broadly similar results .Most of the metasomatic agents (either ﬂuids,supercritical liquids,or melts)released during these experiments have (Th/La)n similar to that of the starting material in agreement with the negligible Th/La fractionation between arc magmas and subducted sediments (Plank,2005).A number of experimental runs have (Th/La)n of about 2,although invariably have (Sm/La)n b 1.In contrast,the TRL depict a positive trend towards (Th/La)n N 8and (Sm/La)n N 1.5which is not observed in any experimental run.The TRL magmas with high Th/La and Sm/La have also high Th/U (see full data compilation in the supplementary material).In contrast,allanite/monazite saturated liquids always have enrichment of U with respect to Th (Klimm et al.,2008;Skora and Blundy,2010).Indeed Klimm et al.(2008)indicated allanite-saturated liquids as suitable candidates to produce the 238U-excesses observed in several volcanic arc magmas.The corollary of these studies is that the ordinary metasomatic agents released during subduction,including those saturated in either allanite or monazite,are unable to produce mantle enrichment zonesand successively magmas with Th/La N 1,Sm/La N 0.3and Th/U N 4.This is actually not surprising considering that allanite and monazite are widely regarded as key minerals in controlling the Th,U and REE budget of typical subduction-related magmas (e.g.Hermann and Rubatto,2009;Klimm et al.,2008;Skora and Blundy,2010),from which the TRL are clearly distinguished (Fig.5).We are thus left to face the apparent inconsistency of the Th/La and Sm/La conundrum of the TRL,which requires a mantle source con-sisting of crust-like and depleted lithospheric mantle domains:the former being responsible for their extreme trace element contents,crust-like trace element patterns and radiogenic isotope (Sr,Nd,Pb)signature,whilst the latter for their major element depleted ﬂavour.However,the positive Th/La vs .Sm/La array delineated by the TRL (Fig.5and Fig.7)suggests the presence of two distinct crustal components:(i)a normal K 2O-rich sediment melt with (Sm/La)n b 1and (Th/La)n ~1(Fig.7),similar to the metasomatic agents typically released during slab dehydration and melting and consistent with the composition of experimental runs;(ii)a SALATHO component with (Sm/La)n N 1.5and (Th/La)n N 8,related to a process not generally occurring in (or recorded by)typical subduction-related geodynamic settings,but yet affecting the TRL mantle sources all along the N 18000km E –W striking Tethyan realm orogenicbelts.Fig.2.87Sr/86Sr i vs.143Nd/144Nd i of rocks belonging to the lamproite clan.The TRL are clearly distinguished from MORBs,OIBs and within-plate lamproites,with the exception of the Western Australia mproite data source as in Table 1,MORB-OIB data source from the compilation of Stracke et al.(2003);BSE:Bulk SilicateEarth.Fig.3.Primitive mantle normalised (Sun and McDonough,1989)incompatible element patterns of the average composition of the different outcropping localities of the TRL.The negative anomalies in Nb-Ta and Ti,along with the positive anomalies at K and Pb mimic the pattern of crustal material (Global Subducting Sediment,GLOSS,Plank and Langmuir,1998;Upper Crust,Rudnick and Gao,2003),and demonstrate the clear subduction-related signature of the TRL.Note the distinctive signature of the TRL in highly incompatible trace element ratios (Rb,Ba,Th,U)in comparison to GLOSS and mproite data source as in Table 1.Fig.4.Ba/Rb vs .Rb/Sr (a),and K/Th vs .Th (b)of the lamproite clan rocks.(a)The TRL have on average higher Rb/Sr and lower Ba/Sr than within-plate lamproites suggesting a major role of phlogopite in their mantle source with respect to the major role of amphibole in the case of other lamproites.The Subcontinental Lithospheric Mantle composition (SCLM,McDonough,1990)is reported for comparison along with qualitative arrows evidencing the expected compositional variation due to amphibole vs .phlogopite mantle metasomatism.(b)The TRL have lower K/Th than other lamproites due to their extreme Th enrichment up to N mproite data source as in Table 1,symbols as in Figure 2.6S.Tommasini et al./Earth and Planetary Science Letters xxx (2010)xxx –xxx。

Retropubic Versus Transobturator

Retropubic Versus Transobturator Midurethral Synthetic Slings:Does One Sling Fit All?Sarah E.McAchranPublished online:13July 2010#Springer Science+Business Media,LLC 2010Abstract The purpose of this article is to evaluate the recent evidence base for the choice between transobturator and retropubic approaches to midurethral slings used to treat stress urinary incontinence.While the retropubic and transobturator approaches to midurethral sling surgery for stress urinary incontinence demonstrate equivalent efficacy across a number of randomized controlled trials,they do not appear to be equivalent when particular patient populations are considered separately.The retropubic approach appears to be a better option in patients with intrinsic sphincter deficiency and limited urethral mobility.Keywords Urinary stress incontinence .Suburethral slingsIntroductionThe optimal surgical management of stress urinary incon-tinence (SUI)remains a controversial topic.The best approach to management varies from patient to patient and must account for individual history,exam findings,and personal expectations.In the past decade,midurethral synthetic sling surgery has become the most popular procedure for the treatment of female SUI.The two main approaches to placement of the synthetic sling are the retropubic and transobturator (TOT)approaches.Debate remains regarding the equivalency of these approaches with respect to surgical outcomes and other factors.A PubMedsearch of the literature published between January 2009and March 2010using the keyword “suburethral slings ”was performed.The following limits were employed:human,sex (female),and language (English).As a result 214articles were retrieved,54of which specifically pertained to the midurethral sling.Of those,25were selected because of their design (prospective randomized study)or unique contribution to the topic:Can retropubic and TOT approaches to midurethral sling surgery be used inter-changeably with equivalent outcomes in all patients?Retropubic Midurethral SlingIn 1995,Petros and Ulmsten [1]introduced a new minimally invasive surgery for the treatment of female SUI,which they named the tension-free vaginal tape (TVT)procedure.Their integral theory of incontinence purports that stress inconti-nence results from the failure of the pubourethral ligaments in the midurethra.The retropubically placed sling is thought to reinforce the functional pubourethral ligaments and thereby secure proper fixation of the midurethra to the pubic bone,allowing for the simultaneous reinforcement of the suburethral vaginal hammock and its connection to the pubococcygeus muscles.Since its inception,numerous studies and large worldwide clinical volume have shown that the retropubic procedure is equivalent to other operations for the treatment of SUI,with a brisk return to normal function and relatively few postoperative complications [2,3].Recently,a study was published on the long-term results of the TVT procedure with a follow-up time of 11years,demonstrating a subjective cure rate of 77%[4].Rare but serious postoperative complications have been reported including injury to bowel and major blood vessels,as well as postoperative voiding difficulties [5,6].S.E.McAchran (*)Department of Urology,1685Highland Avenue,Madison,WI 53705,USAe-mail:mcachran@Curr Urol Rep (2010)11:315–322DOI 10.1007/s11934-010-0131-7Transobturator Midurethral SlingIn2001,Delorme[7]reported the first TOT midurethral sling.This approach,which avoids the retropubic passage of needles,is designed to avoid many of the major complications of the TVT procedure such as injury to suprapubic structures such as bowel,bladder,and major vessels.The initial description of this procedure involved the passage of specifically designed needles from the obturator region of the inner thigh to exit in the suburethral vaginal incision.Shortly after the introduction of the outside-in approach,a procedure that involved the passage of the needle from the vaginal incision to exit at the obturator space was described and named the TVT-O (Gynecare;Ethicon,Inc.,Somerville,NJ)[8].The TOT sling lies under the midurethra at less of an acute angle than the TVT,and therefore,is thought to be less likely to be obstructive[9].Complications do occur,and those reported include bladder perforation,inner thigh and groin pain,and vascular and nerve injury[2,10].Retropubic Versus Transobturator:Historical DataIn2007,Latthe et al.[11]published a meta-analysis of the effectiveness and complications of the TOT and retropubic midurethral sling procedures.This comprehensive review included11randomized controlled trials(RCTs);5com-pared TVT-O to TVT and6compared the TOT approach to TVT.Follow-up for all studies was12months or less.For the purposes of defining cure on the meta-analysis, subjective cure rates were pooled,as these are of prime importance to both patients and clinicians.When compared with the TVT,the subjective cure rate of SUI for both TOT and TVT-O was statistically equivalent.Bladder injury and voiding difficulty were less for combined TOT and TVT-O. The vaginal extrusion rate was higher in the TOT groups (OR,1.51).The pain in the groin and thigh was higher in the TOT slings when compared with the TVT(OR,9.34). De novo urgency and frequency symptoms were equivalent between the TOT and retropubic approaches.The authors concluded that the data to support the short-term superiority of the TOT approach were limited,and that while bladder injuries and voiding difficulties were lower,inner thigh pain and vaginal erosion of the mesh were more common.In2008,Barber et al.[12]published their results of a noninferiority trial comparing the TVT to the Monarc Subfascial Hammock system(American Medical Systems Inc.,Minnetonka,MN),an outside-in TOT approach.This multicenter trial randomized women with SUI to receive a TVT or TOT sling.The primary outcome was the presence or absence of abnormal bladder function.This was a composite outcome designed to capture efficacy as well as adverse events related to the sling,and was defined as the presence of any of the following:incontinence symptoms of any type,a positive cough stress test,or retreatment for stress incontinence or postoperative urinary retention assessed1year after surgery.The mean follow-up was 18.2months±6months.Abnormal bladder function oc-curred in46.6%of the TVT patients and42.7%of the TOT sling patients.The relatively low success rates seen in this trial clearly reflect the very strict definition of cure created by the composite outcome measure.With a P value of 0.006for the one-sided noninferiority test,the TOT tape was determined to be not inferior to the TVT.There were a significantly higher number of bladder perforations seen in the TVT group.In2009,Long et al.[13•]published their meta-analysis of the RCTs comparing the retropubic to the TOT approach published between January2008and March2009.Their results concurred with those of Latthe[11]and Barber[12] with respect to both clinical efficacy and complications. However,they did introduce the concept that the TVT appears to be more obstructive than the TOT,as evidenced by ultrasonographic and urodynamic findings[14].For this reason,they conclude that for women with intrinsic sphincter deficiency(ISD),the TVT appears to be a better option[15].Retropubic Versus Transobturator:Recent Randomized Controlled TrialsIn2009,six more RCTs were published[16,17••,18••,19–21].The results and key findings are summarized in Table1.Karateke et al.[20]analyzed urethral mobility by Q-tip test and sphincteric function as determined by Valsalva leak point pressure(VLPP)and their ability to predict the outcome of TVT and TVT-O.In both groups,no significant difference was demonstrated in the subjective outcomes (evaluated with validated questionnaires)and cure rates between patients with VLPP of60cm H2O or less and those with a VLPP of greater than60cm H2O.These results are contradicted in the study by Rechberger[17••] discussed below.With respect to urethral hypermobility,in patients who demonstrated hypermobility preoperatively, success rates were both good and comparable(94.1%in TVT and94.2%in TVT-O).Cure rates were dramatically and significantly lower in patients with no hypermobility (61.5%for TVT and50%for TVT-O).Based on this,the authors conclude that success of either procedure can be predicted by urethral mobility,but not by competence of the sphincter.The study by Rechberger et al.[17••]reported preoper-ative demographic parameters such as body mass index(BMI)and menopausal status,as well as urodynamic parameters including postvoid residual volume,maximal urethral closure pressure(MUCP),and VLPP.ISD was defined as a VLPP of60cm H2O or less.Women also were categorized according to Stamey grades of incontinence. Statistically significant differences in cure rates between groups with different Stamey incontinence scores were found for the TOT approach but not for the retropubic approach.In this study,among patients with severe symptoms of SUI,TOT slings were less effective than retropubic slings.Additionally,this study found interesting results with respect to outcomes when analyzed according to preoperative VLPP.The18-month efficacy calculated for patients operated on via the TOT route was significantly lower when VLPP was60cm H2O or less.Conversely,the retropubic sling was found to be equally effective across all VLPPs.The study by Ross et al.[18••]concurred with previous studies in that both approaches were not statistically significant with respect to outcome.They did evaluate one unique outcome:digital vaginal examination.In addition to evaluating for mesh extrusion,they also calculated the number of patients on whom the mesh was palpable,and if palpable,if it was tender.A statistically significant difference was found between the TVT(26.7%)and the TOT groups(80%).While the study does not extrapolate the long-term significance of these findings,they do suggest that one potential sequela is an increased rate of sling extrusion over time.Long-term follow-up clearly is necessary so that we can accurately counsel our patients about the long-term likelihood of vaginal mesh extrusion.The study by Wang et al.[19]provides36-month follow-up data,the longest of the recent publications.This study nicely breaks down cure rate at6months,12months, 24months,and36months,and demonstrates that there is not a statistically significant difference at6months and 36months in either the TVT or TVT-O groups.However,it should be noted that the number of patients available for follow-up at the36-month mark was less than25%of the original number studied in both groups.Risk Factors for FailureThe varying cure,complication,and voiding dysfunction rates are important topics to cover during preoperative counseling.Several studies published in the past year have looked at various risk factors that might predispose a particular patient to failure with midurethral slings.Maximal Urethral Closure PressureUsing an MUCP cutoff of20cm H2O,Houwert et al.[22], in a retrospective cohort study designed to evaluate risk factors for failure of the TVT versus the TVT-O and the Monarc Subfascial Hammock(American Medical Systems, Minnetonka,MN),found a statistically significant lower cure rate with the TOT procedures in patients with MUCPTable1Cure rate and complication rate of prospective randomized controlled trials comparing retropubic to transobturator approachesStudy Sling Patients,n Meanfollow-up,moDefinitionof cureCure rate,%De novourge,%Bladderperforation,%Post-opurinaryretention,%Erosion/extrusion,%Aniuliene[16]TVT11412No signs of SUI,no urgency 85.1 5.20.915.8N/ATVT-O15078 5.30 3.3a N/AKarateke[20]TVT8112Negative coughstress test 88.912 3.79.9 2.4TVT-O8386.714.807.2 4.9Krofta[21]TVT14912Negative coughstress test 90.1 6.40.7 2.7N/ATVT-O15188.413.6a0 6.6N/ARechberger [17••]Retropubic(IVS-02)26918Subjective curerate scale75.18.6 6.5 3.52 Transobturator(IVS-04)26874.150a5 2.5Ross[18••]Advantage(RPR)10512Pad test77N/A 2.8 1.1 1.1 Obtryx halo(TOT)9481N/A0 3.57Wang[19]TVT16036Negative coughstress test 82.9 5.8N/A 3.9 1.9TVT-O15583.3 4.1N/A 2.7 2.1N/A not available,RPR retropubic outside-in,SUI stress urinary incontinence,TOT transobturator outside-in,TVT tension-free vaginal tape,TVT-O transvaginal tape-obturatora statistically significantless than20cm ing a cutoff value of42cm H2O, Jung et al.[23]found that an MUCP of42cm H2O or more was predictive of surgical success for the TOT approach but not the retropubic approach.On multivariate logistic regression analysis,Hsiao et al.[24]found that an MUCP of40cm H2O or less was an independent risk factor for failure of the TOT approach but not the retropubic approach.None of the above studies reflects the results of randomized trials;thus,additional confirmatory studies are needed.Mixed IncontinenceThe effect of a midurethral sling procedure on patients with mixed incontinence is still unknown.Interestingly, Hsiao et al.[24]found that detrusor overactivity was an independent risk factor for sling failure in both the retropubic and TOT approaches.In Stav et al.’s[25] study,mixed incontinence carried an odds ratio of2.4for failure of either type of surgery.In Houwert’s[22] retrospective study of387patients,the presence of DO on urodynamic study was an independent risk factor for failure only for the retropubic approach.Therefore,they conclude that in patients with DO,the TOT approach may be more favorable.Certainly,no robust conclusions can be drawn from the above data.Previous Incontinence SurgeryPrevious incontinence surgery is a known risk factor for failure of both retropubic and TOT sling procedures[26, 27].In Houwert’s[22]study evaluating risk factors for failure,prior surgery for incontinence was a risk factor for failure for both retropubic and TOT slings in univariate analysis.On multivariate analysis,only the TOT approach proved to be an independent risk factor.In a similar study by Hsiao et al.[24],previous anti-incontinence surgery was not a risk factor for failure on multivariate analysis for either approach(121patients).Stav et al.[25]published their analysis of risk factors for treatment failure in1,225 consecutive women undergoing midurethral slings for SUI (78%retropubic and22%TOT).Risk factors were not analyzed separately by mode of sling placement.Multivar-iate analysis revealed that the independent risk factors for failure were:BMI(>25),mixed incontinence,previous incontinence surgery,ISD,and diabetes mellitus.The odds ratio for previous incontinence surgery was2.2 Based on the above data,it would seem that patients with previous incontinence surgery have a higher likelihood of failure with midurethral slings.While one study points toward an increased risk with the TOT approach,the number of patients is too small to draw a definite conclusion.Body Mass IndexIn a subset analysis of the data from their RCT discussed earlier,Rechberger et al.[28•]looked specifically at the predictive values of BMI,age,and postmenopausal status. BMI was stratified into the following categories:18.5to 24.9;25to29.9;and greater than or equal to30.The study did not show a statistically significant difference between the efficacy of the TOT and retropubic procedures with regard to BMI.This study supports several previous studies that demonstrated acceptable success rates of midurethral sling surgery in the overweight and obese populations[29–31].The superiority of either approach in this population remains to be determined.Age and Postmenopausal StatusAge and postmenopausal status were explored as potential risk factors for failure in the Rechberger study[28•].Age was stratified into the following categories:less than 50years(n=134);51years to60years(n=144);61years to70years(n=68);and71years and older(n=52). Stepwise logistic regression analysis revealed that increas-ing age(per decade)is an independent risk factor for failure of both the TOT(OR,1.96)and retropubic(OR,1.64) midurethral slings.Evaluated together,both approaches to the midurethral sling were less efficacious in the postmen-opausal compared to the premenopausal groups(P=0.006). However,the overall cure rate was still74.6%.Intrinsic Sphincter Deficiency and Urethral Hypermobility Hosker[32]recently explored the question“Is it possible to diagnose intrinsic sphincter deficiency in women?”That is to say,is there an objective measure that defines all women with very poor urethral closure function?The two most common methods,MUCP less than20cm H2O and VLPP less than60cm H2O,as well as various less common methods,were evaluated with respect to their ability to diagnose ISD.The conclusion drawn was that no definitive test has yet emerged to diagnose ISD and that its measurement is imprecise.While the retropubic and TOT approaches to sling surgery for SUI have been proven in many RCTs to not differ significantly with respect to cure,it has been a generally held belief that women with more severe incontinence or ISD will be more successful with the retropubic approach.This is supported by a recent meta-analysis of the literature that concludes that,when urodynamic evidence of ISD is present,the retropubic approach may be preferable to the TOT approach[33]. However,only three of the included studies were prospec-tive and the number of patients studied was small.A retrospective study of300patients with SUI and ISD as defined by MUCP less than20cm H2O or VLPP less than60cm H2O was performed by Gungorduk et al.[34]. TVT was the procedure for180women,while120had a TOT.Mean follow-up was31.2months.The overall cure rate for the TVT group was78.3%versus52.5%for the TOT group(P<0.0001).This translates into a4.9-times greater risk of failure for the TOT approach.There were no statistically significant differences between other measured outcome parameters,including de novo urgency,short-and long-term voiding dysfunction,and mesh erosion.Rapp et al.[35]published a retrospective review of their results with both the retropubic(n=97)and TOT(n=39) approaches to SUI with ISD.ISD was defined as a VLPP less than60cm H2O.Success was subjectively defined based on questionnaire results as less than one SUI episode per week or greater than70%subjective improvement in those patients with more than one SUI episode per week. No significant differences in continence rates were identi-fied in comparing midurethral slings types across VLPP (50–59,40–49,30–39,and<30cm H2O).However, deterioration in success rates was observed in both retropubic and TOT approaches with more extended follow-up and with lower VLPPs.These data are limited by the low patient numbers and related study power,in particular with more extended follow-up.While the data regarding success of the various approaches to SUI in patients with ISD remain equivocal, the emerging data that are evaluating approaches with respect to urethral mobility are more discerning[36,37••]. Minaglia et al.[36]examined a cohort of134women who underwent a TOT procedure for SUI.Women with preoperative urethral straining angles less than45°from the horizontal were at least five times more likely to report postoperative incontinence compared with women with preoperative straining angles of45°or more.In a small but interesting study from Turkey,65women were divided into three groups:ISD with hypermobile urethra(group1),ISD with fixed urethra(group2),and hypermobile urethra without ISD(group3)[37].ISD was defined as a VLPP less than60cm H2O and urethral hypermobility was defined as a maximum straining angle of more than30°on Q-tip test.Defining cure as a negative cough stress test,outcomes were assessed at6months, 12months,and24months.The cure results were similar for groups1and3at all time points.Group2had the lowest cure and improvement rate(66.7%at24months;P= 0.02).The authors conclude that a lack of urethral hypermobility may be a risk factor for TOT failure.The concept that TOT is less obstructive than TVT,and thus less effective for both ISD and the fixed urethra,is supported by several studies.Hsiao et al.[38]compared the postoperative urodynamic changes in patients with urody-namic stress incontinence that underwent TVT and TOT procedures.This study demonstrated that the TVT had a higher cure rate with a significantly increased MUCP and continence area compared to the TOT procedure at 12months ing ultrasound to assess TVT and TVT-O morphologic changes,Long et al.[14] found that the middle of the TVT-O was located more distally than the TVT at rest and during straining.A higher rate of urethral kinking during straining was noted with the TVT group compared with the TVT-O group(86.9%vs 23.9%).A recent ultrasound study by Yang et al.[39] further adds to the description of the morphologic changes that occur after placement of TOT slings. ComplicationsMidurethral sling complications are well documented in several retrospective studies[2,5,40].In2009,another retrospective review from Switzerland that evaluated complications of233cases recorded at27months follow-up was published[41].Three different types of slings placed between2003and2006were evaluated,including the Aris(Mentor-Porges,Le Plessis Robinson,France), TVT-O,and ObTape(Mentor-Porges,Le Plessis Robinson, France).Early complications were those occurring in the first month after the procedure and late complications occurred after30days.The overall late complication rate, including those associated with the ObTape,was21.3%.As would be expected,the risk of vaginal erosion with the ObTape was significantly higher than with the other two slings at17%,versus4%for the Aris and0%for the TVT-O.The ObTape was a type2mesh with pores smaller than 50μm;since the conclusion of this study,it has been removed from the market because of its known high rate of vaginal erosion[42].Houwert’s[43•]group from the Netherlands recently published a study that used a unique method of evaluating complications of retropubic and TOT midurethral slings. The surgical therapeutic index(STI)is defined as the ratio between the cure and complication rates.The complication rate is calculated by summing complications associated with the performed surgical procedure at a defined moment in time.A higher STI indicates a safer procedure.The TVT was compared to two types of TOT slings(Monarc and TVT-O)at2months and12months.SUI was considered cured if the patient expressed that she did not experience any loss of urine upon physical activity,coughing,or plications included de novo urgency and urge incontinence,voiding difficulty,vaginal mesh erosion, tape release,dyspareunia,and groin pain.At2months,the TOT approach had an STI of9.2and the retropubic approach had an STI of3.4.However,by12months,theTOT approach had lost its advantage,with an STI of5.1 compared to the retropubic(STI6.1).At12months,there were no statistically significant differences between the approaches amongst the evaluated complications.The evaluation of STI may improve preoperative patient counseling by providing a comparable method of calculat-ing the risk-to-benefit ratio of different procedures.Future studies would do well to consider using this as an outcome measure.Sexual FunctionThe effect of midurethral slings on sexual function has been a topic of inquiry over the past several years.The available studies are small with level II evidence;therefore,a meta-analysis evaluating all reports published between1995and 2008regarding midurethral sling surgery and female sexual function was performed by Serati et al.[44].A total of17 papers including904women were included,with12studies receiving particular attention:8examined the retropubic approach and4the TOT approach.For most women,sexual function is either improved or unchanged after undergoing midurethral slings for SUI regardless of the approach.They propose a less than15%chance of developing dyspareunia postoperatively,though two of the three studies that reported higher rates of dyspareunia used nonvalidated questionnaires.A study from2008,in which women were asked to fill out the Female Sexual Function index(FSFI)both before undergoing retropubic and TOT midurethral slings and again at6months,did not find a significant change in overall sexual function for any of the FSFI domains(desire, arousal,lubrication,orgasm,satisfaction,or pain)[45].A small2009study that specifically evaluated sexual function after the TOT approach also used the FSFI as a measure[46].At a mean follow-up of12months,92%of patients were satisfied with sexual relations compared with 84%preoperatively.This study adds to the body of data that seems to suggest that the TOT approach to midurethral slings does not have an adverse effect on female sexual function.A2009study from France specifically evaluated the retropubic versus the TOT approach with respect to female sexual function[47].This retrospective questionnaire-based study found that sexual function outcome did not differ preoperatively and postoperatively for the TVT and TOT groups,and postoperatively between the two groups. Among responders,improvement in sexual function was noted in29.5%of the TVT group and32.9%of the TOT group.Worsening sexual function was a complaint for 17.3%of the TVT group and12.5%of the TOT group. Based on this study,neither the retropubic nor the TOT approach has an advantage with respect to sexual function.Finally,a small but intriguing study from Cholhan et al.[48]explored the significance of paraurethral banding seen after TOT slings.The RCT by Ross et al.[18]noted a statistically significant difference between the ability to feel the sling postoperatively between the retropubic and TOT approaches,with the TOT approach being palpable80%of the time.Similarly,Cholhan et al.’s[48]retrospective review of25TOT slings versus28retropubic slings found that paraurethral banding was palpable in52%of the TOT slings versus0%of the retropubic slings.Paraurethral banding is defined as anterior vaginal wall banding in the paraurethral folds immediately adjacent to the midurethral placement of the ing the FSFI,no statistically significant difference was noted in postoperative sexual function between the two groups.However,de novo dyspareunia was noted in four patients in the TOT group and none in the retropubic group.All of these women displayed paraurethral banding.The significance of the palpability of the TOT slings and its relation to sexual function remains to be delineated and is an area for future research.ConclusionsData regarding the TOT approach to the midurethral sling for SUI continue to accumulate.While RCTs have yet to demonstrate a superiority of one approach over the other with respect to either cure or complications,there are data to suggest worse outcomes with the TOT approach in certain populations:patients with ISD,patients with limited urethral mobility,and those who have previously undergone incontinence surgery.The TOT approach seems to cause greater distortion of the anterior vaginal wall,the signifi-cance of which remains to be determined.Disclosure No potential conflicts of interest relevant to this article have been reported.ReferencesPapers of particular interest,published recently,have been highlighted as:•Of importance••Of major importance1.Petros P,Ulmsten U:Intravaginal slingplasty(IVS):an ambula-tory surgical procedure for treatment of female urinary inconti-nence.Scand J Urol Nephrol1995,29:75–82.2.Novara G,Galfano A,Boscolo-Berto R,et al.:Complication ratesof tension-free midurethral slings in the treatment of female stress。

《历史教学(中学版)》征稿启事

《历史教学(中学版)》征稿启事
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人教网刊《半亩历史》2013年度征稿启事
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紧扣征稿主题，联系时事，如史学动态，考古发现，或结合历史上同期的史实，提供理论指导或传播动态信息。

如相关历史概念的分析，学术研究、历史事件述评，基于现实问题的历史分析等。

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针对教与学中实际遇到或可能遇到的问题，进行答疑；也可以围绕重点，难点，提供独到的案例设计；或谈三维目标的落实策略等。

提倡小目标的精到剖析，不求面面俱到，鼓励不同的观点和争论。

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既可以是心灵独白，亦可以是二三友的谈话。

以小品文为主。

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