105 resultados para WHITE-DWARFS


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Conserved chromosomal segments in the black rhinoceros, Diceros bicornis (DB1, 2n = 84), and its African sister-species the white rhinoceros, Ceratotherim simum (CSI, 2n = 82), were detected using Burchell's zebra (Equus burchellii, EBU, 2n = 44) chromosome-specific painting probes supplemented by a subset of those developed for the horse (Equus caballus, ECA, 2n = 64). In total 41 and 42 conserved autosomal segments were identified in C simum and D. bicornis respectively. Only 21 rearrangements (20 fissions and I fusion) are necessary to convert the Burchell's zebra karyotype into that of the white rhinoceros. One fission distinguishes the D. bicornis and C simum karyotypes which, excluding hetero- chromatic differences, are identical in all respects at this level of resolution. Most Burchell's zebra chromosomes correspond to two rhinoceros chromosomes although in four instances (EBU 18, 19, 20 and 21) whole chromosome synteny has been retained among these species. In contrast, one rhinoceros chromosome (DBI1, CSI1) comprises two separate Burchell's zebra chromosomes (EBU11 and EBU17). In spite of the high diploid numbers of the two rhinoceros species their karyotypes are surprisingly conserved offering a glimpse of the putative ancestral perissodactyl condition and a broader understanding of genome organization in mammals. Copyright (C) 2003 S. Karger AG, Base

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Six sample specimens of Trachypithecus francoisi and 3 of T. leucocephalus were analyzed by use of allozyme electrophoresis and random amplified polymorphism DNA (RAPD) in order to clarify the challenged taxonomic status of the white-head langur. Among the 44 loci surveyed, only 1 locus (PGM-2) was found to be polymorphic. Nei's genetic distance was 0.0025. In total, thirty 10-mer arbitrary primers were used for RAPD analysis, of which 22 generated clear bands. Phylogenetic trees were constructed based on genetic distances using neighbor-joining and UPGMA methods. The results show that T. francoisi and T: leucocephalus are not monophyletic. T. francoisi from Guangxi, China and Vietnam could not be clearly distinguished, and they are not divided into 2 clusters. A t-test was performed to evaluate between genetic distances within and between T. leucocephalus and T. francoisi taxa groups. The statistical test shows that the taxa group within T: leucocephalus and T: francoisi does not significantly differ from that between T: leucocephalus and T: francoisi at the 5% level. Our results suggest that the level of genetic differentiation between T, leucocephalus and T. francoisi is relatively low. Recent gene flow might exist between T. francoisi and T. leucocephalus. Combining morphological features, geographical distribution, allozyme data, RAPD data, and mtDNA sequences, we suggest that the white-head langur might be a subspecies of T. francoisi.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

本文研究了果树害虫脊胸天牛(RhytidoderabowringiiWhite)在云南景谷县果国内对果树枝干的分布和危害情况。结果表明,该害虫在三年和象牙树上主要危害3~5年生枝条,其有虫枝率分别为65.3%和92.0%。另外,按地形将果园分为上、中、下三个区带,分别调查各区活枝、地面枯枝和腐枝中的害虫。结果显示,中区活枝、枯枝、腐枝的有虫枝率分别为60.0%,30.0%和17.0%,其有虫枝率分别高于果园的上区和下区。总体上看,三个区带活枝、枯枝和腐枝的有虫枝率分别为56.8%,34.0%和14.3%。定期清除果国内的枯枝和腐枝是防治脊胸天牛的有效措施之一。

Relevância:

20.00% 20.00%

Publicador:

Resumo:

脊胸天牛是云南芒果树的主要害虫之一。在云南景谷地区两年发生一代, 三年完成, 世代交叉, 因此为害特别严重。通过综合防治, 可基本控制该虫的为害。

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Many systematic relationships among Chinese white-toothed shrews of genus Crocidura are presently unresolved. In this paper, a taxonomic revision of Crocidura from Southern China is presented. We studied 338 specimens from Burma, China, Korea, Pakistan, Turkey, Middle and Central Asia, and Russia (Appendix I), 285 of which had complete skulls that were analyzed with principal component and discriminant analyses. Results indicated that 6 species of Crocidura can be recognized in South China. C. fuliginosa occurs in Southwestern and Eastern China, C. attenuata is broadly distributed throughout Southern China, and C. horsfieldii is restricted to the southern part of China. C vorax and C. rapax, usually placed as synonyms of the European C russula, are recognized as 2 valid species whose ranges overlap in Southwestern China. C. shantungensis of Eastern Asia extends to the northern part of Southern China and is distinct from C. suaveolens and C. gmelini of Middle and Central Asia, respectively.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Prefrontal impairments have been hypothesized to be most strongly associated with the cognitive and emotional dysfunction in depression. Recently, white matter microstructural abnormalities in prefrontal lobe have been reported in elderly patients with ma

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Healthy siblings of schizophrenia patients have an almost 9-fold higher risk for developing the illness than the general population. Disruption of white matter (WM) integrity as indicated by reduced fractional anisotropy (FA) derived from diffusion tensor

Relevância:

20.00% 20.00%

Publicador:

Resumo:

介绍了应用过夜地粪便来估计白马雪山黑白仰鼻猴群大小和组成的一种方法。该物种以单雄多雌单 元和全雄组的形式在树上过夜。粪粒根据其大小可分为3种类型:成年雄性的(最大)、成年雌性的(中等大小)和 未成年个体的(最小)。2000一2001年,搜集了滇西北白马雪山国家级自然保护区北部南任村(99。04 7E,28。34 7N) 附近黑白仰鼻猴群每个季节2个过夜地的粪粒。根据2001年11月猴群通过开阔地的数据来确定猴群组成。每个 季节,由于单雄多雌单元的成年个体数与其粪粒数正相关,所以二者回归直线的斜率可以看作是每个个体每晚 的平均排便量。由于该物种的栖息地主要为高山峡谷,而且能见度较低,因此,利用过夜地粪便比以前通过猴群 活动痕迹来估计猴群大小和组成相对准确、可靠。从估计成年雌性个体数的角度看,利用粪粒来估计种群大约有 9.4%的偏差。导致偏差的可能原因有杂草和灌丛对粪粒准确计数的影响、个体排粪率的差异以及成年雄性最小 粪粒与成年雌性最大粪粒的混淆等。该方法适应于栖息地和主要食物与本文研究种群相似的其他种群。

Relevância:

20.00% 20.00%

Publicador:

Resumo:

寄生物种群γm的精确值与ln(Md)/d或ln(Md/2)/d之间存在着线性关系,这种关系可用两个公式表达: (1) γ_(m)=0.845ln(Md)/d; (2)γ_(m)=0.880ln(Md/2)/d。公式可以给出 γ_(m)的精确估计值, 公式2的估计效果更好。这种方法不要求组建生殖力表。图3表1参14

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Data on sleeping sites of a group of black-and-white snub-nosed monkeys Rhinopithecus bieti (Colobinae, Primates) were collected between April-July and September-December 2001 to try to determine the factors affecting site selection at Nanren (99 degrees

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Data on social organization of two bands of black-and-white snub-nosed monkeys (Rhinopithecus bieti) 14 were collected when the monkeys were crossing an open spot at Nanren and Bamei (northwest of Yunnan, China) using a sampling rule where individuals wit

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Data on mating and birth seasonality were recorded in wild black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Xiaochangdu in the Honglaxueshan National Nature Reserve, Tibet. This represents one of the harshest habitats utilized by any nonhuman p

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A two-week trial was conducted to study the effect of feeding rates on heat shock protein levels in larval white sturgeon. The larvae (30 day post hatch, 230 mg initial body weight) were fed a commercial feed (12.6% moisture, 49.5% crude protein. 20.7% Crude fat, and 8.6% ash) at 5, 15. or 25% body weight per clay (BW d(-1)). Liver heat shock proteins (Hsp) were measured before and after the larvae were subjected to a heat shock from 18 to 26 degrees C at 1 degrees C/15 min and maintained at 26 degrees C for 4 h thereafter. Before heat shock, larvae fed 5% BW d(-1) had significantly (P<0.05) lower final body weight, RNA/DNA ratio, whole body lipid and protein content, and Hsp60 and Hsp70 levels but higher protein efficiency ratio, and whole body moisture content than larvae fed the two higher feeding rates. Heat shock significantly induced Hsp60 and Hsp70 levels in the liver of all fish but they were lower in larvae fed the 5% than those fed 15 and 25% BW d(-1). Hsp70 level increased much more than Hsp60 after the heat shock Suggesting that Hsp70 is a more sensitive biomarker under our experimental conditions. (c) 2008 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

White spot syndrome virus (WSSV) is a major pathogen in shrimp aquaculture. VP28 is one of the most important envelope proteins of WSSV. In this study, a recombinant antibody library, as single-chain fragment variable (scFv) format, displayed on phage was constructed using mRNA from spleen cells of mice immunized with-full-length VP28 expressed in Escherichia coli. After several rounds of panning, six scFv antibodies specifically binding to the epitopes in the N-terminal, middle, and C-terminal regions of VP28, respectively, were isolated from the library. Using these scFv antibodies as tools, the epitopes in VP28 were located on the envelope of the virion by immuno-electron Microscopy, Neutralization assay with these antibodies in vitro suggested that these epitopes may not be the attachment site of WSSV to host cell receptor. This study provides a new way to investigate the structure and function of the envelope proteins of WSSV. (c) 2008 Published by Elsevier Inc.