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排序方式: 共有105条查询结果,搜索用时 406 毫秒
61.
Résumé Des anticorps contre le cristallin et contre le muscle cardiaque de la souris ont été marqués par le radio-iode, puis employés pour la localisation histochimique et pour une analyse quantitative de ces antigènes au cours du développement. 相似文献
62.
为探讨豚鼠耳蜗基底膜的听觉机制,利用多普勒激光测振技术进行了声音在28只成年健康豚鼠耳中传递的测试实验.将豚鼠麻醉后切断头取出听泡,采用电钻暴露其耳蜗基底膜,利用多普勒激光测振仪在给定的声压级、频率的纯音激励条件下测量豚鼠外耳道耳蜗基底膜的振动速度,并测量了中耳镫骨的振动速度.结果表明,豚鼠外耳道基底膜具有频率选择特性,而且其基底膜的振动具有行波特性. 相似文献
63.
基于子波分解计算散射子平均间距的倒谱法 总被引:1,自引:0,他引:1
提出了一种对超声散射信号分析的方法--子波分解(WD)倒谱法,并利用该方法对正常猪肝组织的回波信号进行了分析,对软组织中散射的平均间距进行了估计,与用ARI倒谱法所得结果进行了比较,结果表明:WD倒谱比AR倒谱更能反映软组织的微观结构特征,说明WD倒谱是软组织超声散射信号分析与软组织散射子平均间距定特征的一种有效方法。 相似文献
64.
用线性扫描极谱法和循环伏安法研究奥沙普秦在0.05mol.L-1HAc-NaAc缓冲溶液(pH5.18)中的电化学行为。奥沙普秦于-1.221V(vs.SCE)处产生一灵敏的吸附波,奥沙普秦浓度在4.0μg.L-1~2000.0μg.L-1范围时,其一次微分线性扫描峰电流与奥沙普秦浓度呈良好的线性关系,相关系数r=0.99920(n=15),检出限为2.4μg.L-1。对200.0μg.L-1奥沙普秦溶液进行6次平行试验,RSD为1.02%,回收率在94.3%~96.2%之间,方法可用于其在片剂中含量的测定。 相似文献
65.
浅议施工企业工程项目效益评估 总被引:1,自引:0,他引:1
谭森林 《科技情报开发与经济》2004,14(6):258-259
简述了工程项目效益评估产生的背景及在确定项目经济技术承包指标管理活动中所发挥的作用,详细介绍了工程项目效益评估的内容、依据及评估的程序。 相似文献
66.
Barnes C Plagnol V Fitzgerald T Redon R Marchini J Clayton D Hurles ME 《Nature genetics》2008,40(10):1245-1252
Copy number variation (CNV) is pervasive in the human genome and can play a causal role in genetic diseases. The functional impact of CNV cannot be fully captured through linkage disequilibrium with SNPs. These observations motivate the development of statistical methods for performing direct CNV association studies. We show through simulation that current tests for CNV association are prone to false-positive associations in the presence of differential errors between cases and controls, especially if quantitative CNV measurements are noisy. We present a statistical framework for performing case-control CNV association studies that applies likelihood ratio testing of quantitative CNV measurements in cases and controls. We show that our methods are robust to differential errors and noisy data and can achieve maximal theoretical power. We illustrate the power of these methods for testing for association with binary and quantitative traits, and have made this software available as the R package CNVtools. 相似文献
67.
Recent calculations provide convincing evidence that the naturally occurring nuclei were produced in explosions. The required temperature, density and expansion rate strongly suggest that before the explosion the objects were ordinary evolved massive stars. We review these new developments and present a new table indicating our hypothesis concerning the origin of the nuclei in the mass range 20 < or = A < or = 62. 相似文献
68.
Large falcons (genus Falco ) do not build their own nests and, in North America at least, usually nest on high cliffs. Occasionally they nest in abandoned stick nests built by another large bird on the cliff. In Asia and particularly South Africa, they sometimes nest in stick nests on electrical transmission towers. This use of electric transmission towers was recently (1980) reported for the Prairie Falcon ( Falco mexicanus ) in North America but is unknown, except for 1 anocdotically documented use of an ""electric-power pole"" at the turn of century in California, for the Peregrine Falcon ( Falco peregrines ) in North America. Here we report such nesting of the peregrine in North America and additional tower nestings of the Prairie Falcon. 相似文献
69.
马尔可夫链是一种特殊的随机过程.应用它的计算方法,对随机变量进行马尔可夫分析,利用转移概率求出稳定状态概率,从而选择出最佳的决策方案.通过实例,阐述了马尔可夫模型在市场销售和设备维修中的应用. 相似文献
70.
Sandilands A Terron-Kwiatkowski A Hull PR O'Regan GM Clayton TH Watson RM Carrick T Evans AT Liao H Zhao Y Campbell LE Schmuth M Gruber R Janecke AR Elias PM van Steensel MA Nagtzaam I van Geel M Steijlen PM Munro CS Bradley DG Palmer CN Smith FJ McLean WH Irvine AD 《Nature genetics》2007,39(5):650-654
We recently reported two common filaggrin (FLG) null mutations that cause ichthyosis vulgaris and predispose to eczema and secondary allergic diseases. We show here that these common European mutations are ancestral variants carried on conserved haplotypes. To facilitate comprehensive analysis of other populations, we report a strategy for full sequencing of this large, highly repetitive gene, and we describe 15 variants, including seven that are prevalent. All the variants are either nonsense or frameshift mutations that, in representative cases, resulted in loss of filaggrin production in the epidermis. In an Irish case-control study, the five most common European mutations showed a strong association with moderate-to-severe childhood eczema (chi2 test: P = 2.12 x 10(-51); Fisher's exact test: heterozygote odds ratio (OR) = 7.44 (95% confidence interval (c.i.) = 4.9-11.3), and homozygote OR = 151 (95% c.i. = 20-1,136)). We found three additional rare null mutations in this case series, suggesting that the genetic architecture of filaggrin-related atopic dermatitis consists of both prevalent and rare risk alleles. 相似文献