993 resultados para 796.015


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This is the Restormel Fish Counter, Annual Report 2007 produced by the Environment Agency South West Region on March 2008. The report presents the upstream counts of migratory salmonids recorded on the River Fowey at Restormel Weir fish counting station (SX 107 613) over the period March 2007 to February 2008 inclusive. Data contained within this report covers the period of the commercial migratory salmonid net buy-back scheme and the National Spring Salmon Byelaws (2 March- 15 June). The minimum upstream salmon estimate for 2007, over the period July 2007 to February 2008, was 796, which is the fifth highest recorded count over the past 13 years. The number of returning salmon in 2007 suggests a downward trend in numbers since 2004. The 2007 large sea trout count is similar to 2006. Overall, the number of fish returning is still low in comparison with the 10-year average. There was a noticeable decrease in the number of small sea trout returning compared to 2006 and the 10-year average. The Fish counter at Restormel suffered several faults.

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石荠苎属(Mosla (Benth.) Buch.-Hamilt. ex Maxim.)是唇形科的一个小属,仅分布于东亚,该属复杂的变异式样一直困扰着系统学家.本论文是对该属进行三年物种生物学研究的结果.本研究从居群生物学出发,在广泛的野外调查后选取了47个居群进行取样和观察,在控制环境因素的实验设计条件下,测量了31个居群53个形态性状并分析了其变异规律;在扫描电镜下观察了含外类群在内的6属38个居群的花粉和小坚果表面微形态:对27个居群做了细胞学研究:对22个居群15个酶系统做了等位酶分析,获得了28个位点的资料;进行了35个组合的796次人工杂交.综合上述各方面资料的分析结果,对石荠苎属的形态变异与进化、居群分化、生殖隔离、物种形成、类群划分,以及起源和扩展作了详细的分析和讨论. 形态特征的数量遗传学分析表明,叶片大小和形状、苞片形态、花序(果序)和花萼(果期花萼)的复杂变异式样是造成分类混乱的主要原因.叶片大小和形状在小鱼仙草(M. dianthera)中呈现幅度很宽的连续变异,极端情况常分别被描述为不同的种,如M.remottllora和M.grosseserrata.少数突变体以及种间偶尔产生的杂交个体在苞片和花序形态上表现异常,都曾引起分类的混乱.本研究已经澄清M. bracteata和M. tamdaoensis是突变体,而M. exfoliata和M. longispica则是种间杂种.M.fomosana花萼上唇裂片长度的变异是导致分类困难的另一个原因,是小鱼仙草花萼上唇中裂片变异的极端类型。 通过比较分析揭示了石荠苎属中苞片形状、花序结构、花朵大小、花萼形态、小坚果和花粉粒表面纹饰以及染色体的变异和演化趋势,苞片由发达的叶状类型向披针形方向演化;花序由花朵疏离的松散状向紧缩的头状类型演化;花萼由近辐射对称,五个裂片近等长向二唇形演化;花冠由发达、鲜艳向退化方向演化:小坚果由具旋涡状深雕纹向具网纹类型演化;花粉粒由无明显突起向有明显条文或块状突起的类型演化;核型由不对称性小向不对称性增强发展;繁育系统由以异交为主向以自交为主演化,并且带动一系列花部形态的相关变异. 等位酶分析结果表明,石荠苎属种内的进化以遗传变异的积累和繁育系统的转变造成的居群间分化为主要特征.杭州石荠苎各居群的平均遗传距离为0.026,聚类分析结果发现7个居群明显分化为两支,居群3704,4704和3712为一支,其他居群为一支,等位酶资料获得的结果也得到形态和生殖特征的支持.3704、4704和3712在毛被、花朵大小、小坚果大小和颜色在均与其他居群有差异,繁育系统上,这三个居群表现出更明显的异交特性.小鱼仙草居群之间遗传分化甚至大于少数亲缘种之间的遗传分化,平均遗传距离达到0.034,但杂交实验发现,居群之间并不存在生殖隔离,不同的居群之间在叶片大小、叶形、苞片长短和花萼上唇中裂片的长短也有所不同.杭州石荠苎和小鱼仙草种内居群之间的形态和等位酶分化说明居群之问正处于分化和物种形成的早期阶段,生殖隔离还没有建立。 突变(包括染色体结构变异)的积累和繁育系统的转变是石荠苎属物种形成的基础,苏州石荠苎和石荠苎的分化是由于染色体结构变异的积累,具体表现在核型不对称性上的差异,造成生殖隔离.另一些比较明显的物种形成机制为:染色体多倍化,形成M.pauciflora;染色体结构变异,如随体染色体的臂间易位,产生M.cavaleriei;繁育系统由异交转变为自交产生M.chinensis.另外,在物种形成过程中,花期和生态位分化等促进了生殖隔离的完善. 石荠苎属形态上界限清楚,而且存在生殖隔离的种有八个,它们是小花荠苎(M.cavaleriei Levl.);石香薷 (M. chinensis Maxim.);小鱼仙草 (M. dianthera (Buch.-Hamilt. ex Roxb.) Maxim.);杭州石荠苎(M.hangchouensis Matsuda);日本石荠苎(M. japonica (Benth.) Maxim.);疏花荠苎(M. pauciflora (C. Y. Wu) C. Y. Wu et H. W. Li);石荠苎(M. punctulata (J.F. Gmelin) Nakai)和苏州石荠苎(M. soochouensis Matsuda). 石荠苎属的近缘属是香薷属(Elsholtzia)、香简草属(Keiskea)和紫苏属(Perilla)。石荠苎属与近缘属的分化大约在260万年之前,因为那时石荠苎属的祖先就发生了分化,形成以杭州石荠苎一一石香薷的祖先和以小花荠苎一一小鱼仙草的祖先为代表的两条进化主线,从香薷属和香简草属的现代分布式样-以及石荠苎属的分布特点推断,华东地区可能是石荠苎属的起源和演化的舞台,华东地区具有最大的种类多样性、变异性、特有性和多度.

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We discuss the long-range interactions that arise in homogeneous turbulence as a consequence of the Biot-Savart law. We note that, somewhat surprisingly, these long-range correlations are very weak in decaying, isotropic turbulence, and we argue that this should also be true for magnetohydrodynamic, rotating and stratified turbulence. If this is indeed the case, it is possible to make explicit predictions for the rate of decay of energy in these anisotropic systems, and it turns out that these predictions are consistent with the available numerical and experimental evidence.

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We measured growth and movements of individually marked free-ranging juvenile white shrimp (Litopenaeus setiferus) in tidal creek subsystems of the Duplin River, Sapelo Island, Georgia. Over a period of two years, 15,974 juvenile shrimp (40−80 mm TL) were marked internally with uniquely coded microwire tags and released in the shallow upper reaches of four salt marsh tidal creeks. Subsequent samples were taken every 3−6 days from channel segments arranged at 200-m intervals along transects extending from the upper to lower reach of each tidal creek. These collections included 201,384 juvenile shrimp, of which 184 were marked recaptures. Recaptured shrimp were at large an average of 3−4 weeks (range: 2−99 days) and were recovered a mean distance of <0.4 km from where they were initially marked. Mean residence times in the creek subsystems ranged from 15.2 to 25.5 days and were estimated from exponential decay functions describing the proportions of marked individuals recaptured with increasing days at large. Residence time was not significantly correlated with creek length (Pearson=−0.316, P=0.684 ), but there was suggestive evidence of positive associations with either intertidal (Pearson r=0.867, P=0.133) or subtidal (Pearson r=0.946, P=0.054) drainage area. Daily mean specific growth rates averaged 0.009 to 0.013 among creeks; mean absolute growth rates ranged from 0.56−0.84 mm/d, and were lower than those previously reported for juvenile penaeids in estuaries of the southeastern United States. Mean individual growth rates were not significantly different between years (t-test, P>0.30) but varied significantly during the season, tending to be greater in July than November. Growth rates were size-dependent, and temporal changes in size distributions rather than temporal variation in physical environmental factors may have accounted for seasonal differences in growth. Growth rates differed between creeks in 1999 (t-test, P<0.015), but not in 1998 (t-test, P>0.5). We suggest that spatial variation in landscape structure associated with access to intertidal resources may have accounted for this apparent interannual difference in growth response.

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本发明涉及一种强抗氧化活性的组合物,包括仿刺参多肽和香菇多糖,它们间的质量比是1:1-100。采用南京建成生物工程研究所试剂盒(T-AOC)测定酶解液总抗氧化活性。结果发现:木瓜蛋白酶水解后的仿刺参酶解液抗氧化活性明显增强,由最初的10.08单位/mg蛋白增至27.59单位/mg蛋白;将无抗氧化活性的香菇多糖浸提液按照不同比例和仿刺参酶解液混合后,组合物的抗氧化活性可进一步提升。当仿刺参酶解液与香菇多糖浸提液体积比为1:4时,抗氧化活性达到最高值84.09单位/mg蛋白,相应对照组的抗氧化活性则为47.54单位/mg蛋白。研究结果表明木瓜蛋白酶水解可以增强仿刺参的抗氧化活性,而香菇多糖浸提液又可进一步增强仿刺参酶解产物的抗氧化活性。本发明可用于具有增强机体抗氧化活性、延缓衰老的功能性食品的开发。

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Amphibian skin is a rich resource of antimicrobial peptides like maximins and maximins H from toad Bombina maxima. A novel cDNA clone encoding a precursor protein that comprises maximin 3 and a novel peptide. named maximin H5. was isolated from a skin cDNA library of B. maxima. The predicted primary structure of maximin H5 is ILGPVLGLVSDTLDDVLGIL-NH2,. Containing three aspartate residues and no basic amino acid residues. maximin H5 is characterized by an anionic property. Different from cationic maximin H peptides. only Gram-positive strain Staphylococcus aureus was sensitive to maximin H5. while the other bacteria] and fungal strains tested ere resistant to it. The presence of metal ions. like Zn2+ and Mg2+, did not increase its antimicrobial potency. Maximin H5 represents the first example of potential anionic antimicrobial peptides from amphibians, The results provide the first evidence that. together kith cationic antimicrobial peptides. anionic antimicrobial peptides may also exist naturally as part of the innate defense system. (C), 2002 Elsevier Science (USA). All rights reserved.

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In 6 Chinese yak (Bos. grunniens) populations including 177 yaks, 34 blood protein loci were studied by horizontal starch gel electrophoresis, four of these loci (AKP: ALB, LDH-1, TF) were found to be polymorphic. The percentage of polymorphic loci(P) is 0.118, the mean individual heterozygosity(H) is 0.015, which means a low level of genetic diversity in the whole Chinese yak population. The coefficient of gene differentiation (G(ST)) is 0.0625, which indicated an almost-indistinguishable divergence among different populations at the level of blood protein electrophoresis.