MECHANISM OF THE HYDROLYSIS OF ADENOSINE 5＇-TRIPHOSPHATE: A REGRESSION ANALYSIS OF KINETIC DATA     

D.BRYNNHIBBERT  JOHNP.B.SANDALL 《地理学报(英文版)》1989,(3)

Data of the hydrolysis of adenosine 5'-triphosphate have been re-evaluated using a computer program thatnumerically integrates the differential rate equations within a routine that optimizes rate coefficients givena suitable model and concentration versus time data. The model is tested by calculation of Hamilton R-values, the Fisher F-statistic, a sensitivity analysis,the standard errors on the rate coefficients and by constructing contour maps of the objective functionversus two rate coefficients. An optimization using only phosphate concentration data cannot distinguish between a model in whichadenosine 5'-monophosphate is formed predominantly directly with a molecule of pyrophosphate, andone in which it is formed via adenosine 5'-diphosphate. A more accurate set of rate coefficients iscalculated from existing data and the relative importance of the two paths determined.  相似文献   

Distinction between Permian and post-Permian igneous rocks in the southern Sydney Basin, New South Wales, on the basis of major-element geochemistry     

Paul F. Carr 《Mathematical Geology》1981,13(3):193-200

Permian and post-Permian igneous rocks of the southern Sydney Basin of New South Wales can be distinguished on the basis of major-element geochemistry. A data base of 102 analyses of these igneous rocks has been used to evaluate the effectiveness of various discriminants based on univariate and multivariate analysis. Inspection of histograms of compositional frequency for each major-element oxide is an efficient method of univariate analysis and assigns up to 92.2% of the rocks to the correct age group. Discriminant function analysis using up to 10 variables does not produce a more efficient discriminant than the simple binary plot of SiO ₂ versus TiO ₂,which assigns 95.1% of the rocks to the correct age group. No other binary or ternary diagram commonly used in petrology produces such an efficient discriminator.  相似文献   

WIYN Open Cluster Study – XVI. Optical/infrared photometry and comparisons with theoretical isochrones     

Aaron J. Grocholski  Ata Sarajedini 《Monthly notices of the Royal Astronomical Society》2003,345(3):1015-1029

We present combined optical/near-infrared photometry ( BVIK ) for six open clusters – M35, M37, NGC 1817, NGC 2477, NGC 2420 and M67. The open clusters span an age range from 150 Myr to 4 Gyr and have metal abundances from  [Fe/H]=−0.27  to +0.09 dex. We have utilized these data to test the robustness of theoretical main sequences constructed by several groups as denoted by the following designations – Padova, Baraffe, Y², Geneva and Siess. The comparisons of the models with the observations have been performed in the  [ M_V , ( B − V )₀], [ M_V , ( V − I )₀]  and  [ M_V , ( V − K )₀]  colour–magnitude diagrams as well as the distance-independent  [( V − K )₀, ( B − V )₀]  and  [( V − K )₀, ( V − I )₀]  two-colour diagrams. We conclude that none of the theoretical models reproduces the observational data in a consistent manner over the magnitude and colour range of the unevolved main sequence. In particular, there are significant zero-point and shape differences between the models and the observations. We speculate that the crux of the problem lies in the precise mismatch between theoretical and observational colour–temperature relations. These results underscore the importance of pursuing the study of stellar structure and stellar modelling with even greater intensity.  相似文献   

BOOK REVIEWS     

《The Professional geographer》1982,34(4):458-490

Books reviewed in this article: Aerial Photography and Remote Sensing. Terrain Analysis and Remote Sensing . JOHN R. G. TOWNSHEND , ed. Environmental Data Use in Computer-assisted Data Handling Systems: The Results of a Survey of Applications in the Pacific Northwest States . KENNETH E. GORDON . Applied Land Use: A Spatial Approach . JOHN F. LOUNSBURY , LAWRENCE M. SOMMERS , AND EDWARD A. FERNALD , eds. The Second Battle of New Orleans: A History of the Vieux Carre Riverfront-Expressway Controversy . RICHARD O. BAUMBACH , JR. AND WILLIAM E. BORAH . Cultural Environmental Archaeology . MYRA SHACKLEY . The Immoral landscape: Female Prostitution in Western Societies . RICHARD SYMANSKI . life Among the Poor in Cairo . UNNI WIKAN , translated by Ann Henning. Women, Work and Property in Northwest India . URSULA SHARMA . The Domestication of Women: Discrimination in Developing Societies . BARBARA ROGERS Economic Optimization in Locational and Transport Analysis . A. G. WILSON , J. D. COELHO , S. M. MACGILL , H. C. W. L. WILLIAMS . New Tools for Economic Development: The Enterprise Zone, Development Bank, and RFC . GEORGE STERNLIEB AND DAVID LISTOKIN , eds. Regional Wage Inflation . R. L. MARTIN , ed. Finding A Place For Energy-Siting Coal Conversion Facilities . FRANK J. CALZONETTI WITH MARK S. ECKERT . Environmental Management, Resources, and Systems Environmentalism. Second Edition . T. O'RIORDAN . Countryside Conservation . BRYN GREEN . Medical Spatial Diffusion: An Historical Geography of Epidemics in an Island Community . A. D. CLIFF , P. HAGGETT , J. K. ORD , AND G. R. VERSEY . Philosophy and Geographic Thought Order and Skepticism: Human Geography and the Dialectic of Science . RICHARD SZYMANSKI AND JOHN A. AGNEW . Measurement of Subjective Phenomena . D. F. JOHNSTON , ed. Conceptions of Space in Social Thought: A Geographic Perspective . ROBERT DAVID SACK . The Association of American Geographers: The First Seventy-five Years: 1904-1979 . PRESTON E. JAMES AND GEOFFREY J. MARTIN . The Life and Thought of Isaiah Bowman . GEOFFREY J. MARTIN . Physical River Basin Planning: Theory and Practice . SURANJIT K. SAHA AND CHRISTOPHER J. BARROW , eds. Soils and landforms: An Integration of Ceomorphology and Pedology . A. I. GERRARD Climatic Change and Society. Consequences of Increasing Atmospheric Carbon Dioxide . WILLIAM W. KELLOGG AND ROBERT SCHWARE . Political Political Redistrictings and Geographic Theory . RICHARD L. MORRILL . Population Studies in Spanish American Population History: Dell Plain Latin American Studies NO. 8 . DAVID J. ROBINSON , ed. Population Redistribution in the Midwest . CURTIS C. ROSEMAN , ANDREW J. SOFRANKO , AND JAMES D. WILLIAMS , eds. Geographical Perspectives on the Elderly . A. M. WARNES , ed. Regional Perspective On the American South . MERLE BLACK AND JOHN SHELTON REED , eds. The Prairies and Plains: Prospects for the 80s . JOHN R. ROGGE , ed. Rural Rural Settlement in an Urban World . MICHAEL BUNCE . Social Accident at Three Mile Island: The Human Dimensions . DAVID L. SILLS , C. P. WOLF , AND VIVIEN B. SHELANSKI , eds. The American Small Town: Twentieth-Century Place Images . JOHN JAKLE . Urban A House of My Own . SUSAN LOBO . The City: Patterns and Processes in the Urban Ecosystem . CHRISTOPHER H. EXLINE , GARY L. PETERS , AND ROBERT P. LARKIN . Movement in Cities . P. W. DANIELS AND A. M. WARNES . Urbanization and Urban Planning in Capitalist Society . MICHAEL DEAR AND ALLEN J. SCOT , eds.  相似文献   

Properties of iron at the Earth's core conditions   总被引：2，自引：0，他引：2  

Orson L. Anderson 《Geophysical Journal International》1986,84(3):561-579

Summary. The phase diagram of iron up to 330 GPa is solved using the experimental data of static high pressure (up to 11 GPa) and the experimental data of shock wave data (up to 250 GPa). A solution for the highest triple point is found ( P = 280 GPa and T = 5760 K) by imposing the thermodynamic constraints of triple points. This pressure of the triple point is less than the pressure of the inner core–outer core boundary of the Earth. These results indicate that the density of iron at the inner core–outer core boundary pressure is close to 13 g cm⁻³, which lies close to the seismic solutions of the Earth at that pressure. It is thus concluded that the Earth's inner core is very likely to be virtually pure iron in its hexagonal close packed (hcp) phase.
It is shown that four properties of the Earth's inner core determined from seismology are close in value to the corresponding properties of hcp iron at inner core conditions: density, bulk modulus, longitudinal velocity, and Poisson's ratio. The density–pressure profile of hcp iron at inner core conditions matches the density–pressure profile of the inner core as determined by seismic methods, within the spread of values given by recent seismic models.
This indicates that the Earth is slowly cooling, the Earth's inner core is growing by crystallization, and the impurities of the core are concentrated in the outer core. The calculated temperature at the Earth's centre is 6450 K.  相似文献   

中国大陆7级强震前地下流体前兆时空特征   总被引：5，自引：0，他引：5  

晏锐  黄辅琼  顾瑾平 《地震》2004,24(1):126-131

对中国大陆1969年以来11次7级强震前地下流体前兆观测资料分阶段进行统计分析,并选用雷达图描述了中国大陆7级强震前地下流体前兆异常的时空特征,认为其特征主要表现在：异常出现时间上的阶段性与不均匀性,中长期趋势性异常分散,短临异常相对集中,且各占总异常比例的50％左右;震前异常集中在一定的范围内,并沿活动断裂呈现出一定的集中性;中长期趋势异常较早出现在震源区附近,并呈现出由震源区向外围扩散-收缩-扩散-收缩的过程,特别是进入短临阶段后,异常向震源区收缩的趋势更为明显;在震源区(或在距震源较近的范围内)异常所占的比例大,远离震源区所占比例小,且有由震源区向外围逐渐减小的趋势。  相似文献   

基于互联网信息的城市商业游憩网点空间竞争域划分研究     

曹瑞  李仁杰  傅学庆  张军海 《地理与地理信息科学》2012,28(3):54-58,67

提出了一种基于互联网信息的空间竞争域划分方法。在Voronoi图的模型中尝试以网络平台数据作加权因子,使空间竞争域体现互联网中的消费者偏好差异,通过对加权Voronoi图的类型划分和地理学解释,描述竞争环境的空间特征。以北京市健身俱乐部为例,选择大众点评网、爱帮等网络平台信息作为权重因子,构建样本网点的传统Voronoi、互联网信息加权Voronoi计算模型并对比边界线、面积等空间特征分析的结果表明:互联网信息对城市商业游憩网点的空间竞争力产生着不同的影响强度,对Voronoi图空间特征的分类和地理解释可以指示商业网点跨越距离阻碍的消费吸引力及竞争差异,弥补传统加权方法未考虑消费者偏好和购物习惯而对竞争域划分表达不足的缺点。  相似文献   

平面离散点集拓扑邻近稳定区域计算模型     

刘万增  陈军  闫超德  赵仁亮  赵勇  孙文彬 《测绘学报》2012,41(1):127-0

本文利用Voronoi图及其对偶Delaunay三角网研究了平面离散点集拓扑邻近稳定区域的计算方法,证明了点的拓扑邻近稳定区域必须满足的两个条件,给出了点的拓扑邻近稳定区域定量计算模型,并通过实验证明其正确性。  相似文献   

西北干旱区夏半年深厚的混合层与干旱气候形成   总被引：8，自引：3，他引：5       下载免费PDF全文

李岩瑛  钱正安  薛新玲  兰晓波  李玲萍 《高原气象》2009,28(1):46-54

为了更好地理解西北干旱区大气混合层(ML)厚度的变化特征及其对当地干旱气候形成的影响,我们利用张掖和民勤站夏季及相关月的实测探空资料及T-log P图解法,首先计算了该两地逐日ML厚度,然后分析并讨论了它的时空间变化特征、与干湿天气气候的关系,以及夏半年的深厚ML,对加剧当地干旱气候的影响.结果表明:(1)河西中东部ML厚度的年变化及地区差异明显.冬季最浅薄,夏半年深厚(特别是5、6月),4月及10月分别是ML急剧增厚及变薄的过渡期;同时,更靠近西北干旱区中心的河西西部及北部的ML更深厚.(2)夏季干(湿)天气通过加强(减弱)地气间的感热交换和干对流,而明显影响当地的ML厚度.平均而言,以高温日最深厚,千日次之,小雨日再次之,而中强雨日最浅薄.千年夏季的ML厚度平均比湿年的对应值增厚300 m左右.夏季典型千日的ML厚度比雨日厚3000 m,典型干日的ML厚度昼宿变化不大.(3)反过来夏半年深厚的ML也通过增加雨滴蒸发损耗,减少了干旱区的降水,加剧了当地干旱的程度,因此夏半年深厚的ML也是形成干旱气候背景的成因之一.  相似文献   

上海地区最高气温资料的恢复试验   总被引：3，自引：0，他引：3  

李庆祥  黄嘉佑  鞠晓慧 《热带气象学报》2008,24(4):349-353

对上海最高气温1924～2001年期间的缺测资料进行了恢复试验,以期通过该个例的研究,探讨我国台站历史资料集中缺测或中断序列的恢复、插补的一般方法.选取使用上海气象观测站的相邻若干台站的最高气温资料,分别用回归分析法、判别分析法和偏最小二乘法,对上海站相应期间缺测资料进行逐年逐月的恢复,并利用交叉检验的均方误差作为恢复效果的评判.结果发现对缺测资料恢复的总效果以偏最小二乘法为最好,因此选用该方法作为资料恢复的主要方法.恢复过程为每次仅恢复某月份、某测站、某年份的缺测资料,恢复后的估计值作为观测值使用,再进行其它缺测资料恢复的新资料集,如此反复地进行,以近期资料开始,逐步向前期资料延拓.这样做的目的是为了使得和后续的观测资料直接连接.  相似文献