Local changes in snow depth dominate the evolving pattern of elevation-dependent warming on the Tibetan Plateau

Elevation-dependent warming (EDW),whereby warming rates are stratified by elevation,may increase the threat to the life-supporting solid water reservoir on the ...     

多因素层次模糊综合评判决策模型及其应用

应用系统工程的方法，建立基于三角模糊数学的多因素层次模糊，综合评判决策模型和权重分配待定性因素数值化模型，并运用该模型对某贵金属矿体开采的采矿方法进行了优选，获得了满意的结果。     

辐射与组培复合育成“霞光”等14个菊花新品种

辐射诱变与组织培养相结合，育成了“霞光”等１４个菊花新优品种；对品种来源及形态特征进行了简要描述，并对有关育种技术问题进行了讨论。     

变系数Helmholtz方程本征值问题差分近似的六阶校正法

给出了变系数Helmholtz方程的六阶高精度校正法。此校正过程几乎不增加工作量，而校正后精度比未校正提高了四阶，并能提供后验误差估计。同时，对于常系数Helmholtz方程，给出了八阶校正格式。     

基于MPI的eclipse并行计算在油藏模拟中的应用

随着进行油藏模拟数据量增加,计算步骤日渐复杂,利用传统计算机来模拟,为了达到理想的模拟速度和效果,其硬件平台的投资将很高。本文设计并实现一种通过在windows下配置mpich2以建立的eclipse parallel并行计算,通过交换器和网线建立PC集群代替原有单个计算机来做油藏模拟。利用eclipse parallel,我们模拟并实现并行平台的要求,四台计算机同时计算程序,一台显示结果,通过使用实际数据对并行油藏模拟的稳定性和并行效率进行测试,测试显示在PC集群系统上高效运行eclipse进行油藏模拟模拟计算是可行的。     

邻氨基噻唑偶氮类试剂质子化机理的研究

邻氨基噻唑偶氮类试剂［１～３］在不同酸度下呈现不同的颜色,关于其质子化发生的位置以及先后次序至今尚未见文献报道．本文通过量子化学计算,结合分光光度法对这类试剂质子化行为进行了研究．１实验方法１．１吸收光谱测定移取１．０ｍＬ１．０×１０－３ｍｏｌ／ＬＴ...     

Loss of ACTN3 gene function alters mouse muscle metabolism and shows evidence of positive selection in humans

More than a billion humans worldwide are predicted to be completely deficient in the fast skeletal muscle fiber protein alpha-actinin-3 owing to homozygosity for a premature stop codon polymorphism, R577X, in the ACTN3 gene. The R577X polymorphism is associated with elite athlete status and human muscle performance, suggesting that alpha-actinin-3 deficiency influences the function of fast muscle fibers. Here we show that loss of alpha-actinin-3 expression in a knockout mouse model results in a shift in muscle metabolism toward the more efficient aerobic pathway and an increase in intrinsic endurance performance. In addition, we demonstrate that the genomic region surrounding the 577X null allele shows low levels of genetic variation and recombination in individuals of European and East Asian descent, consistent with strong, recent positive selection. We propose that the 577X allele has been positively selected in some human populations owing to its effect on skeletal muscle metabolism.     

Wnt-beta-catenin signaling initiates taste papilla development

Fungiform taste papillae form a regular array on the dorsal tongue. Taste buds arise from papilla epithelium and, unusually for epithelial derivatives, synapse with neurons, release neurotransmitters and generate receptor and action potentials. Despite the importance of taste as one of our five senses, genetic analyses of taste papilla and bud development are lacking. We demonstrate that Wnt-beta-catenin signaling is activated in developing fungiform placodes and taste bud cells. A dominant stabilizing mutation of epithelial beta-catenin causes massive overproduction of enlarged fungiform papillae and taste buds. Likewise, genetic deletion of epithelial beta-catenin or inhibition of Wnt-beta-catenin signaling by ectopic dickkopf1 (Dkk1) blocks initiation of fungiform papilla morphogenesis. Ectopic papillae are innervated in the stabilizing beta-catenin mutant, whereas ectopic Dkk1 causes absence of lingual epithelial innervation. Thus, Wnt-beta-catenin signaling is critical for fungiform papilla and taste bud development. Altered regulation of this pathway may underlie evolutionary changes in taste papilla patterning.     

CCD精密测量系统及其数字信号处理

介绍了ＣＣＤ精密测量系统中的信号采集和处理的工作原理,阐述了测量系统和数字信号处理芯片（ＤＳＰ芯片）在系统中的工作原理,同时还介绍了测量系统的软件工作过程。文中概要介绍了ＣＣＤ器件的工作原理和ＣＣＤ器件用于测量中的特点。通过本文,我们可以了解到ＣＣＤ精密测量系统中ＤＳＰ芯片的作用。     

非完整复曲线的坐标计算

复曲线两交点间未设置基线而采用两圆曲线的切线交叉连接,是高速公路中较特殊线路形式.本文通过对非完整复曲线的分析、研究,介绍了在进行此类复曲线放样前所用的坐标计算方法.