新疆少数民族中学"体育与健康"课程教学现状的调查与研究

本对新疆南、北疆、东疆地区和乌鲁木齐市的101所民族中学进行实地的调查研究，通过对各民族中学体育教学中大纲、教材、场地器材、汉语授课、男女生分班情况、教师培训、教学计划以及对课程改革的认识等方面的分析．进一步了解新疆各地区民族中学学校体育状况，特别是“体育与健康”课程实施后，各地区民族中学学校体育教学现状以及所面临的问题，旨在加快新疆少数民族中学的体育教学改革和《体育与健康》课程教学研究。为新疆教育主管部门制定实施“体育与健康”课程教学提供决策依据。     

Why large-scale climate indices seem to predict ecological processes better than local weather

Large-scale climatic indices such as the North Atlantic Oscillation are associated with population dynamics, variation in demographic rates and values of phenotypic traits in many species. Paradoxically, these large-scale indices can seem to be better predictors of ecological processes than local climate. Using detailed data from a population of Soay sheep, we show that high rainfall, high winds or low temperatures at any time during a 3-month period can cause mortality either immediately or lagged by a few days. Most measures of local climate used by ecologists fail to capture such complex associations between weather and ecological process, and this may help to explain why large-scale, seasonal indices of climate spanning several months can outperform local climatic factors. Furthermore, we show why an understanding of the mechanism by which climate influences population ecology is important. Through simulation we demonstrate that the timing of bad weather within a period of mortality can have an important modifying influence on intraspecific competition for food, revealing an interaction between climate and density dependence that the use of large-scale climatic indices or inappropriate local weather variables might obscure.     

Experimental coupling of crab (Carcinus maenas) second maxilla neural motor to an alternating current

Summary Movements of the crab gill bailer were entrained to an alternating current applied to the thoracic ganglion. There was little distortion of the muscle recruitment cycle, both absolute and relative coordination were observed, and the phase of the driven system in the driving cycle was a function of the difference between free running and driving frequencies.I am grateful to ProfessorK. Simkiss for providing facilities in the Department of Zoology, Reading University. Some of the equipment was provided by University of Otago Research Committee grant No. 37-097.     

Global patterns of human mitochondrial DNA and Y-chromosome structure are not influenced by higher migration rates of females versus males

Global-scale patterns of human population structure may be influenced by the rate of migration among populations that is nearly eight times higher for females than for males. This difference is attributed mainly to the widespread practice of patrilocality, in which women move into their mates' residences after marriage. Here we directly test this hypothesis by comparing global patterns of DNA sequence variation on the Y chromosome and mitochondrial DNA (mtDNA) in the same panel of 389 individuals from ten populations (four from Africa and two each from Europe, Asia and Oceania). We introduce a new strategy to assay Y-chromosome variation that identifies a high density of single-nucleotide polymorphisms, allows complete sequencing of all individuals rather than relying on predetermined markers and provides direct sequence comparisons with mtDNA. We found the overall proportion of between-group variation (Phi(ST)) to be 0.334 for the Y chromosome and 0.382 for mtDNA. Genetic differentiation between populations was similar for the Y chromosome and mtDNA at all geographic scales that we tested. Although patrilocality may be important at the local scale, patterns of genetic structure on the continental and global scales are not shaped by the higher rate of migration among females than among males.     

The fine structure of cloned cells from normal adult rat brain

Summary A cell clone was isolated from a normal adult rat brain culture and maintained in vitro for many passages. It possessed glial characteristics; in particular ultrastructural examination revealed astrocytic features including the presence of filaments 9–11 nm in diameter.Acknowledgments. The work was partly supported by a grant from the Cancer Research Campaign to JPR. The secretarial help of Miss Hilary A. Waddington is gratefully acknowledged.     

部门动态投资系数的求取方法探讨

本文从理论和实践两个方面对动态投入产出法中动态投资的概念、投资系数的求取等进行了研究,提出了部门动态投资系数的求取方法,即一次性投资与多次性投资的综合方法。在此基础上,还给出了投资系数的修正方法,分析了影响投资系数求取的因素。最后,给出了投资系数求取过程中的误差分析方法。