995 resultados para 7140-332


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Fecundity in striped mullet (Mugil cephalus) from South Carolina correlated highly with length and weight, but not with age. Oocyte counts ranged from 4.47 × 105 to 2.52 × 106 in 1998 for fish ranging in size from 331 mm to 600 mm total length, 2.13 × 105to 3.89 × 106in 1999 for fish ranging in size from 332 mm to 588 mm total length, and 3.89 × 105 to 3.01 × 106 in 2000 for fish ranging in size from 325 mm to 592 mm total length. The striped mullet in this study had a high degree of variability in the size-at-age relation-ship; this variability was indicative of varied growth rates and compounded the errors in estimating fecundity at age. The stronger relationship of fecundity to fish size allowed a much better predictive model for potential fecundity in striped mullet. By comparing fecundity with other measures of reproductive activity, such as the gonadosomatic index, histological examination, and the measurement of mean oocyte diameters, we determined that none of these methods by themselves were adequate to determine the extent of reproductive development. Histological examinations and oocyte diameter measurements revealed that fecundity counts could be made once developing oocytes reached 0.400 μm or larger. Striped mullet are isochronal spawners; therefore fecundity estimates for this species are easier to determine because oocytes develop at approximately the same rate upon reaching 400 μm. This uniform development made oocytes that were to be spawned easier to count. When fecundity counts were used in conjunction with histological examination, oocyte diameter measurements, and gonadosomatic index, a more complete measure of reproductive potential and the timing of the spawning season was possible. In addition, it was determined that striped mullet that recruit into South Carolina estuaries spawn from October through April.

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A pin-on-disc apparatus has been used to obtain continuous simultaneous measurements of the wear and friction (sliding force) behaviour of metals on bonded silicon carbide abrasive paper under conditions of controlled humidity. Iron, mild steel, and copper exhibit qualitatively similar wear behaviour; the wear rate decreases progressively with the number of passes over the same track. In contrast, the wear rate of titanium remains constant. Variation in atmospheric humidity has little effect on the wear rates of copper or titanium, although a slight effect was found in mild steel and iron. Refs.

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The prehistoric peopling of East Asia by modern humans remains controversial with respect to early population migrations. Here, we present a systematic sampling and genetic screening of an East Asian-specific Y-chromosome haplogroup (O3-M122) in 2,332 individuals from diverse East Asian populations. Our results indicate that the O3-M122 lineage is dominant in East Asian populations, with an average frequency of 44.3%. The microsatellite data show that the O3-M122 haplotypes in southern East Asia are more diverse than those in northern East Asia, suggesting a southern origin of the O3-M122 mutation. It was estimated that the early northward migration of the O3-M122 lineages in East Asia occurred similar to 25,000-30,000 years ago, consistent with the fossil records of modern humans in East Asia.

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本发明涉及大蹼铃蟾神经营养肽及其制备方法和其基因,属于生物医学领域。其神经营养肽为从中国两栖类动物大蹼铃蟾(Bombina maxima)皮肤分泌物中分离得到的由77个氨基酸组成的一种单链多肽,分子量8044.7,等电点8.4,多肽氨基酸全序列一级结构为:AVITGVCDRDAQCGSGTCCAASAFSRNIRFCVPLGNNGEECHPASHKVPYNGKRLSSLCPCNTGLTCSKSGEKFQCS。制备方法是收集大蹼铃蟾皮肤分泌物,离心去除沉淀、冷冻干燥后,经凝胶过滤、高压液相反相柱层析分离纯化后即得到。编码神经营养肽的基因由404个核苷酸组成,其中编码成熟神经营养肽为第102-332位核苷酸。其基因作为基因工程制备神经营养肽的应用。

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目的:解释平顶猴成为唯一能够被HIV-1感染的旧大陆猴以及在被SIV感染时出现较其他旧大陆猴严重临床症状的原因.方法:参考人TRIM5α基因的结构和序列合成引物,以平顶猴DNA 为模板,分别扩增其TRIM5α基因编码序列的所有外显子.利用生物学软件分析获得的编码序列,分析在已经明确与TRIM5α抗病毒功能密切相关的几个位点上是否发生可能影响其功能的突变.结果:在平顶猴基因组上CypA基因融合到TRIM5α基因第八外显子的下游,融合方式与在鹰猴中发现的CypA与TRIM5α的融合方式完全不同.恒河猴TRIM5α基因具有限制HIV-1复制的功能,第332位脯氨酸对其抗病毒功能非常重要,但在平顶猴的TRIM5α上,该氨基酸突变成谷氨酰胺;第335位以后8个氨基酸对恒河猴TRIM5α抗病毒功能也有重要影响,但在平顶猴的TRIM5α上,与其对应的氨基酸片段不仅缺失了两个氨基酸,还有两个氨基酸发生突变,附近区域还有另外两个发生突变.在平顶猴TRIM5α基因的Coiled-Coil结构域插入了13个氨基酸,但没有影响到编码框.结论:在平顶猴的基因组上CypA与TRIM5α的融合以及平顶猴TRIM5α基因抗病毒功能关键位点上的氨基酸突变可能影响其抗病毒功能,是其成为唯一能够被HIV-1感染的旧大陆猴以及在被SIV感染时出现较其他旧大陆猴严重临床症状的重要原因.

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193头健康、经产的黑白花奶牛分为3个组,用3种不同的方法进行同期发情处理和胚胎移植。第1组:注射1次Lutalyse;第2组:注射2次Lutalyse;第3组:注射Fertagyl-Lutalyse-Fertagyl。结果表明:第1组和第2组之间的同期发情胚胎移植率无显著差异(P>0.05),分别为26.5%(21/79)和27.0%(18/68);第3组的同期发情胚胎移植率为60.9%(28/46),显著高于第1组和第2组(P<0.05)。

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2010年2月12—13日,在西藏日喀则樟木镇海拔2070m及1900m处的公路旁分别观察并拍摄到一种鸟类。根据观察资料及所拍照片,鉴定为黑颏穗鹛

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把1870-2001年来自美国"现代灵长类文献题录数据库"、"维普中文数据库"及"中国灵长类研究文献题录"的资料按4个时期(I:1870-1949;Ⅱ:1950-1965;Ⅲ:1966-1977;Ⅳ:1978-2001)分类整理.此外,使用了"科学引文数据库(扩展版)".结果如下:(1)1870-2001年共有20 52篇文献,2个文献数量高峰分别出现于1950-1965和1978-2001年;科研部门所发表的论文占54.2%,并随时间而增加;而国外部门则随之减少.(2)2 052篇文献中,超过9%的文献为SCI所收录,其中1966-1977年被SCI收录的文献百分比最高;在全部被SCI收录的文献中又以科研部门的占优势(59.1%);但国外部门则以其30.1%的文献被SCI收录而领先.(3)统计了灵长类研究9个领域文献百分比及其变化,其中1978-2001间生态学和行为、神经生物学、繁殖和饲养快速发展;化石灵长类、形态学和解剖学减少;分类及分布、细胞及分子进化显得不甚突出;在第Ⅱ时期和第Ⅳ时期疾病防治研究相当多;保护生物学得到越来越多的关注.第Ⅳ时期作者数量最多,但每个作者的文献平均数却不如第Ⅰ时期.一般地说,在SCI收录的作者中以中国作者居多,但在第I时期唯一被SCI收录的作者则是一名外国学者;在第Ⅲ时期外国作者占被收录作者数的60%.

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:用紫撬泽兰精油的20℃~150。C,150℃一200℃,20.0℃,230℃.230屯。300℃和300℃以上馏协,分剐以 稚.簦嘴,L的熏蒸浓爰楚理米象、玉采象、簿豆象牵蚕熹象,螬幕表磷凄5争犍静中,娃15。℃~200℃馏傍转荣虫活性 最高,其洗是20℃一150℃和200℃~230气馏份,而300℃以上馏份的杀虫活性靛低。进一步的生测结装表明.150屯一 200℃增傍对米象、玉来氧、绿黛象和善豆象24h的l(葡分莉为15 5li4,17.8124,培.0302和16.2671mg/Lo