Impairment of sea urchin sperm quality by UV-B radiation: predicting fertilization success from sperm motility

Sperm quality of the sea urchin, Anthocidaris crassispina, after exposure to environmentally realistic UV-B irradiances, was assessed by changes in sperm motility (measured by the computer-assisted sperm analysis (CASA) system), and related to subsequent fertilization success. Percentage motile sperm of A. crassispina declined significantly after exposure to a UV-B dose of 16.2 kJ m(-2), while sperm motion velocity as measured by curvilinear velocity (VCL), straight line velocity (VSL), and average path velocity (VAP) showed significant reduction after exposure to a UV-B dose of 5.4 kJ m(-2). A parallel study showed that fertilization success was significantly reduced after sperm were exposed to UV-B doses > or = 5.4 kJ m(-2). Notably, the four sperm motility parameters were strongly correlated with fertilization success (P < 0.001), followed the increasing order: VSL (r = 0.8) < % motile sperm (r = 0.804) < VCL (r = 0.912) < VAP (r = 0.928). Fertilization success is best predicted by VAP using the exponential model: y = 8.678 + 90.202/[1 + exp(82.83 - x)/10.27)] (r(2) = 0.95). Thus, impairment of sperm motility of sea urchin, as measured by the CASA method, can be used to predict reproductive success and ecological effects.     

Regional diversity in some aspects of Indian demography

Regional variations in the demography of India are explored using official data for the period 1971-1981. Socioeconomic and cultural determinants of such differentials, particularly female education and economic diversification, are addressed.     

Urban growth in Siberia and the Soviet Far East: multiplier effects of Japanese-supplied plants

The author analyzes changes in population growth rates and in the structure of the labor force in Soviet cities where Japanese-supplied industrial plants are located. Data for cities of over 50,000 inhabitants were obtained from available Soviet statistical sources; operations research techniques were then used to yield information at the city level     

卫片数字图象处理与地质解译

利用遥感技术进行地质研究和矿产调查已成为国内外有关地质科技人员普遍关心的问题。但目前我国主要还是靠目视解译,虽然也取得了不少成功的经验,但毕竟还受一些主观因素的限制。为了提高图象处理的质量,加快遥感技术的推广使用,作者使用美制“101数字图象处理系统”对两盘卫星磁带(蓟县幅密云水库地区和北京幅)作了多种方法的处理。下面结合计算机专用子程序对常用的处理方法的数学模型及部分处理结果作一概略的论述。     

辽东半岛金矿分布规律与遥感图象判译

对辽宁清原地区和丹东—岫岩地区的控制金矿构造的影象特征进行了深入研究,并结合地球物理和地质资料进行综合分析和解译,对该区控制金矿的线性构造、环形构造和条带状褶曲构造的图象标志和特征进行了系统总结,提出条带状褶曲、线性断裂和与岩体有关的环形构造的叠加或复合,是本区寻找金矿的主要构造标志。     

Microbialite morphostratigraphy as a tool for correlating Late Cambrian-Early Ordovician sequences

Microbialite morphostratigraphy is a new tool for intrabasinal correlation using diverse microbialite structures (morphotypes). The recognition of the succession of morphotypes over constrained temporal intervals and broad areas is a function of the complex interactions that operate to create the structure. Because so many nonlinked variables (e.g., biotic, sedimentological, physicochemical) are involved, similar morphotypes do not reoccur over long temporal intervals. To demonstrate the technique, the upper Cambrian-lowermost Ordovician shelf strata of the Great Basin, United States, were correlated using both morphostratigraphy and standard lithostratigraphy. Six morphozones and one morphosubzone were recognized, as were four main lithologic successions. Because the boundaries between the morphozones and lithologic successions did not coincide, it is inferred that the characteristics of the various microbialite structures are not solely controlled by physical factors. The principles for establishing a morphostratigraphy outlined in this article allow for the potential to correlate along other ancient marine margins in both the same Cambrian and Ordovician interval, as well as any interval in the Phanerozoic in which diverse microbialite structures occur.