检索结果-南通市图书馆

Bone density, microarchitecture and stiffness in Caucasian and Caribbean Hispanic postmenopausal American women

Bone Research 2014年第3期2卷 194-202页

作者： Bin Zhou Ji Wang Emily m Stein Zhendong Zhang Kyle K Nishiyama Chiyuan A Zhang Thomas L Nickolas Elizabeth shane X Edward Guo Bone Bioengineering Laboratory Department of Biomedical Engineering Columbia University Division of Endocrinology Department of Medicine Columbia University Department of Orthopedic Surgery First Affiliated Hospital School of Medicine Shihezi University

Hispanic Americans of Caribbean origin are a fast-growing subset of the US population, but there are no studies on bone density, microstructure and biomechanical integrity in this minority group. In this study, we aimed to compare Caucasian and Caribbean Hispanic postmenopausal American women with respect to these characteristics. Thirty-three Caribbean Hispanics were age-matched to thirty-three Caucasian postmenopausal women. At the lumbar spine, the Hispanic women had significantly lower areal bone mineral density （aBmD）. At the radius by high-resolution peripheral quantitative computed tomography （HR-pQCT）, there were minimal differences between Hispanic and Caucasian women. At the tibia, Hispanic women had lower trabecular volumetric bone density and trabecular number, and higher trabecular separation. Individual trabecula segmentation （ITS） analyses indicated that at the tibia, Hispanic women not only had significantly lower bone volume fraction, but also had significantly lower rod bone volume fraction, plate trabecular number, rod trabecular number and lower plate-plate, plate-rod and rod-rod junction densities compared to Caucasian women. The differences in bone quantity and quality contributed to lower whole bone stiffness at the radius, and both whole bone and trabecular bone stiffness at the tibia in Hispanic women. In conclusion, Hispanic women had poorer bone mechanical and microarchitectural properties than Caucasian women, especially at the load-bearing distal tibia.

关键词： bone DXA Bone density microarchitecture and stiffness in Caucasian and Caribbean Hispanic postmenopausal American women

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

美国蛋品工业与沙门氏菌鸡蛋召回事件

引用

中国牧业通讯 2011年第7期 50-52页

作者： simon shane 志强

尽管2010年美国沙门氏菌感染稳居新闻头条的时期终于告一段落，但美国蛋品工业仍未平静，仍直面着这些细菌。

关键词：沙门氏菌感染美国工业蛋品事件召回鸡蛋

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Global kinematics of tectonic plates and subduction zones since the late Paleozoic Era

引用

Geoscience Frontiers 2019年第3期10卷 989-1013页

作者： Alexander Young Nicolas Flament Kayla maloney simon Williams Kara matthews Sabin Zahirovic R.Dietmar müller School of Earth and Environmental Sciences University of Wollongong EarthByte Group School of Geosciences The University of Sydney Sydney Informatics Hub The University of Sydney

Detailed global plate motion models that provide a continuous description of plate boundaries through time are an effective tool for exploring processes both at and below the Earth's surface. A new generation of numerical models of mantle dynamics pre-and post-Pangea timeframes requires global kinematic descriptions with full plate reconstructions extending into the Paleozoic(410 ma). Current plate models that cover Paleozoic times are characterised by large plate speeds and trench migration rates because they assume that lowermost mantle structures are rigid and fixed through time. When used as a surface boundary constraint in geodynamic models, these plate reconstructions do not accurately reproduce the present-day structure of the lowermost mantle. Building upon previous work, we present a global plate motion model with continuously closing plate boundaries ranging from the early Devonian at 410 ma to present *** analyse the model in terms of surface kinematics and predicted lower mantle structure. The magnitude of global plate speeds has been greatly reduced in our reconstruction by modifying the evolution of the synthetic Panthalassa oceanic plates, implementing a Paleozoic reference frame independent of any geodynamic assumptions, and implementing revised models for the Paleozoic evolution of North and South China and the closure of the Rheic Ocean. Paleozoic(410-250 ma) RmS plate speeds are on average ～8 cm/yr, which is comparable to mesozoic-Cenozoic rates of ～6 cm/yr on *** global median values of trench migration trend from higher speeds(～2.5 cm/yr) in the late Devonian to rates closer to 0 cm/yr at the end of the Permian(～250 ma), and during the mesozoic-Cenozoic(250-0 ma) generally cluster tightly around ～1.1 cm/yr. Plate motions are best constrained over the past 130 myr and calculations of global trench convergence rates over this period indicate median rates range between 3.2 cm/yr and 12.4 cm/yr with a present day median rate estimat

关键词： Tectonic reconstruction Paleozoic Plate velocities Subduction zone kinematics Lower mantle structure South China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

National/Global Synergy in the Development of Higher Education and Science in China since 1978

引用

Frontiers of Education in China 2018年第4期13卷 486-512页

作者： simon mARGINSON ESRC/OFSRE Centre for Global Higher Education Department of EducationUniversity of OxfordOxfordOX13JAUK

The paper reviews the rapid development of higher education and science in China in the last forty *** discusses the conditions and strategies of that development,including the ways that it embodies a distinctive Chinese approach to higher *** particular,the paper reflects on the policies whereby China coordinated with globalization in higher education and science after 1978,in building national capacity and global ***,nation-state policy goals and accelerated investment on their own are necessary but not sufficient(otherwise Saudi Arabia’s research universities would be stronger than they are).The effective national/global synergy developed by China,made possible by the international openness and part-devolution to science communities that was implemented in the Deng Xiaoping era,has been crucial in the rapid rise of China’s universities and *** national/global synergy-and its potentials,tensions and limits-in turn has determined the nature of the achievement and will shape its future evolution.

关键词： China higher education universities research science globalization devolution Deng Xiaoping

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

molybdenite Re-Os,titanite and garnet U-Pb dating of the magushan skarn Cu-mo deposit,Xuancheng district,middle-Lower Yangtze River metallogenic Belt

引用

Geoscience Frontiers 2021年第3期12卷 399-415页

作者： Yue Li Feng Yuan simon m.Jowitt Fangyue Wang Xiangling Li Yufeng Deng Yunyue Wang Taofa Zhou School of Resources and Environmental Engineering Hefei University of TechnologyHefei 23009China Anhui Province Engineering Research Center for mineral Resources and mine Environments Hefei University of TechnologyHefei 23009China Department of Geoscience University of Nevada Las Vegas4505 S.Maryland Pkwy.NV 89154-4010USA

The magushan skarn Cu-mo deposit is a representative example of the skarn mineralization occurring within the Xuancheng ore district of the middle-Lower Yangtze River metallogenic Belt of eastern *** precise age of an ore deposit is important for understanding the timing of mineralization relative to other geological events in a region and to fully place the formation of a mineral deposit within the geological context of other processes that occur within the study ***,we present new molybdenite Re-Os and titanite and andradite garnet U-Pb ages for the magushan deposit and use these data to outline possible approaches for identifying genetic relationships in geologically complex *** spatial and paragenetic relationships between the intrusions,alteration,and mineralization within the study area indicates that the formation of the magushan deposit is genetically associated with the porphyritic ***,this is not always the case,as some areas contain complexly zoned plutons with multiple phases of intrusion or mineralization may be distal from or may not have any clear spatial relationship to a *** means that it may not be possible to determine whether the mineralization formed as a result of single or multiple magmatic/hydrothermal *** such,the approaches presented in this study provide an approach that allows the identification of any geochronological relationships between mineralization and intrusive events in areas more complex than the study *** published zircon U-Pb data for the mineralization-related porphyritic granodiorite in this area yielded an age of 134.2±1.2 ma(mSWD=1.4)whereas the Re-Os dating of molybdenite from the study area yielded an isochron age of 137.7±2.5 ma(mSWD=0.43).The timing of the mineralizing event in the study area was further examined by the dating of magmatic accessory titanite and skarn-related andradite garnet,yielding U-Pb ages of 136.3±2.5 ma(mSWD=3.2)and 135.9±2.7 ma(mSWD=2.

关键词： magushan skarn deposit molybdenite Re-Os dating Titanite U-Pb dating Garnet U-Pb dating Xuancheng ore district middle-Lower Yangtze River metallogenic Belt

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nonlinear shear behavior of rock joints using a linearized implementation of the Barton-Bandis model

引用

Journal of Rock mechanics and Geotechnical Engineering 2017年第4期9卷 671-682页

作者： simon Heru Prassetyo marte Gutierrez Nick Barton Department of Civil and Environmental Engineering Colorado School of Mines Golden CO 80401 USA Nick Barton and Associates Oslo Norway

Experiments on rock joint behaviors have shown that joint surface roughness is mobilized under shearing,inducing dilation and resulting in nonlinear joint shear strength and shear stress *** displacement *** Barton-Bandis(B-B) joint model provides the most realistic prediction for the nonlinear shear behavior of rock *** B-B model accounts for asperity roughness and strength through the joint roughness coefficient(JRC) and joint wall compressive strength(JCS) ***,many computer codes for rock engineering analysis still use the constant shear strength parameters from the linear mohr-Coulomb(m-C) model,which is only appropriate for smooth and non-dilatant *** limitation prevents fractured rock models from capturing the nonlinearity of joint shear *** bridge the B-B and the m C models,this paper aims to provide a linearized implementation of the B-B model using a tangential technique to obtain the equivalent m-C parameters that can satisfy the nonlinear shear behavior of rock *** equivalent parameters,namely the equivalent peak cohesion,friction angle,and dilation angle,are then converted into their mobilized forms to account for the mobilization and degradation of JRC under *** conversion is done by expressing JRC in the equivalent peak parameters as functions of joint shear displacement using proposed hyperbolic and logarithmic functions at the pre-and post-peak regions of shear displacement,***,the pre-and post-peak joint shear stiffnesses are derived so that a complete shear stress-shear displacement relationship can be *** of the linearized implementation of the B-B model show that the shear stress-shear displacement curves,the dilation behavior,and the shear strength envelopes of rock joints are consistent with available experimental and numerical results.

关键词： Rock joints Joint shear behavior Friction and dilation Barton-Bandis(B-B) model Equivalent mohr-Coulomb(m-C) parameters

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Tritrophic interactions between parasitoids and cereal aphids are mediated by nitrogen fertilizer

引用

Insect Science 2015年第6期22卷 813-820页

作者： muhammad A. Aqueel Abu-bakar m. Raza Rashad m. Balal muhammad A. Shahid Irfan mustafa muhammad m. Javaid simon R. Leather Division of Biology Imperial College London Silwood Park Campus Ascot SL5 7PY UK University College of Agriculture Department of Biological Sciences University of Sargodha Pakistan Department of Crop and Environment Sciences Harper Adams UniversityShropshire TFIO 8NB UK

Host plant nutritional quality can directly and indirectly affect the third trophic levels. The aphid-parasitoid relationship provides an ideal system to investigate tritrophic interactions （as the parasitoids are completely dependent for their development upon their hosts） and assess the bottom up forces operating at different concentrations of nitrogen applications. The effects of varying nitrogen fertilizer on the performance of Aphidius colemani （V.） reared on Sitobion avenae （E） and Aphidius rhopalosiphi （D.） reared on Rhopalosiphum padi （L.） were measured. Parasitism and percent emergence ofparasitoids were positively affected by nitrogen fertilizer treatments while developmental duration （egg, larval, and pupal stages） was not affected by increasing nitrogen inputs. In males and females of both parasitoid species, adult longevity increased with the increasing nitrogen fertilizer. Hind tibia length and mummy weight of both parasitoid species increased with nitrogen fertilizer concentrations, as a result of larger aphids. This study showed that nitrogen application to the soil can have important consequences for aboveground multitrophic interactions.

关键词： cereal aphid parasitoids nitrogen fertilization tritrophic interactions

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

On-the-fly active learning of interpretable Bayesian force fields for atomistic rare events

引用

npj Computational materials 2020年第1期6卷 1502-1512页

作者： Jonathan Vandermause Steven B.Torrisi simon Batzner Yu Xie Lixin Sun Alexie m.Kolpak Boris Kozinsky Department of Physics Harvard UniversityCambridgeMA 02138USA John A.Paulson School of Engineering and Applied Sciences Harvard UniversityCambridgeMA 02138USA Center for Computational Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA Department of mechanical Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA Bosch Research CambridgeMA 02139USA

machine learned force fields typically require manual construction of training sets consisting of thousands of first principles calculations,which can result in low training efficiency and unpredictable errors when applied to structures not represented in the training set of the *** severely limits the practical application of these models in systems with dynamics governed by important rare events,such as chemical reactions and *** present an adaptive Bayesian inference method for automating the training of interpretable,low-dimensional,and multi-element interatomic force fields using structures drawn on the fly from molecular dynamics *** an active learning framework,the internal uncertainty of a Gaussian process regression model is used to decide whether to accept the model prediction or to perform a first principles calculation to augment the training set of the *** method is applied to a range of single-and multi-element systems and shown to achieve a favorable balance of accuracy and computational efficiency,while requiring a minimal amount of ab initio training *** provide a fully opensource implementation of our method,as well as a procedure to map trained models to computationally efficient tabulated force fields.

关键词： fields element typically

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Immunocytochemical localization of carbonic anhydrase in the pseudobranch tissue of the rainbow trout Oncorhynchus mykiss

引用

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2014年第2期15卷 194-200页

作者： S.m.RAHIm A.G.mAZLAN K.D.simon J.P.DELAUNOY P.LAURENT Department of Biology Faculty of Education University of Tikrit School of Environmental and Natural Resource Sciences Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia marine Ecosystem Research Centre Faculty of Science and Technology Universiti Kebangsaan Malaysia Laboratoire de Diagnostic Génétique Faculté de Médcine et CHRU Department of Biology McMaster University

Pseudobranch function has long interested scientists, but its role has yet to be elucidated. Several studies have suggested that pseudobranchs serve respiratory, osmoregulatory, and sensory functions. This work investigated the immunolocalization of pseudobranch carbonic anhydrase （CA） in the teleost fish species rainbow trout （Oncor- hynchus mykiss） to clarify its physiological function. CA was purified from rainbow trout gills O. mykiss and specific antibodies were raised. Immunoblotting between tissue homogenates of pseudobrench and gill CA antibodies showed specific immunostaining with only one band corresponding to CA in the pseudobranch homogenate. Results of im- munohistochemical technique revealed that CA was distributed within pseudobranch cells and more precisely in the apical parts （anti-vascular） of cells. The basal （vascular） parts of cells, tubular system, blood capillaries, and pillar cells were not immunostained. Immunocytochemistry confirmed these results and showed that some CA enzyme was cytoplasmic and the remainder was linked to membranous structures. The results also showed that the lacunar tissue tayers did not display immunoperoxidase activity. Our results indicated that pseudobranch CA may have a function related to the extracellular medium wherein CA intervenes with the mechanism of stimulation of afferent nerve fibers.

关键词： Pseudobranch Carbonic anhydrase Rainbow trout Immunohistochemistry Immunocytochemistry Physiology

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Alignment between galaxies and large-scale structure

引用

Chinese Journal of Astronomy and Astrophysics 2009年第1期9卷 41-58页

作者： A. Faltenbacher Cheng Li simon D. m. White Yi-Peng Jing Shu-De mao Jie Wang max-Planck-Institute for Astrophysics Karl-Schwarzschild-Str. 1 D-85741 Garching Germany mPA/SHAO Joint Center for Astrophysical Cosmology at Shanghai Astronomical Observatory Shanghai 200030 China Jodrell Bank Centre for Astrophysl＇cs Alan Turing Building The University of Manchester Manchester M13 9PL UK Department of Physics Institute of Computational Cosmology University of Durham Science Laboratories South Road Durham DH1 3LE UK

Based on the Sloan Digital Sky Survey DR6 （SDSS） and the ＇millennium Simulation （mS）, we investigate the alignment between galaxies and large-scale structure. For this purpose, we develop two new statistical tools, namely the alignment correlation function and the cos（20）-statistic. The former is a two-dimensional extension of the traditional two-point correlation function and the latter is related to the ellipticity correlation function used for cosmic shear measurements. Both are based on the cross correlation between a sample of galaxies with orientations and a reference sample which represents the large-scale structure. We apply the new statistics to the SDSS galaxy catalog. The alignment correlation function reveals an overabundance of reference galaxies along the major axes of red, luminous （L 〉～L＊） galaxies out to projected separations of 60 h-lmpc. The signal increases with central galaxy luminosity. No alignment signal is detected for blue galaxies. The cos（2θ）-statistic yields very similar results. Starting from a mS semi-analytic galaxy catalog, we assign an orientation to each red, luminous and central galaxy, based on that of the central region of the host halo （with size similar to that of the stellar galaxy）. As an alternative, we use the orientation of the host halo itself. We find a mean projected misalignment between a halo and its central region of -25°. The misalignment decreases slightly with increasing luminosity of the central galaxy. Using the orientations and luminosities of the semi-analytic galaxies, we repeat our alignment analysis on mock surveys of the mS. Agreement with the SDSS results is good if the central orientations are used. Predictions using the halo orientations as proxies for cen- tral galaxy orientations overestimate the observed alignment by more than a factor of 2. Finally, the large volume of the mS allows us to generate a two-dimensional map of the alignment correlation function, which shows the reference galaxy distrib

关键词： dark matter halos clustering-galaxies large-scale structure of Universe- cosmology theory -dark matter

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：