993 resultados para 195-1201
Resumo:
In order to understand how mandibular structure differs among the Chinese cercopithecoids (Rhinopithecus, Trachypithecus and Macaca), particularly the uniqueness of the snub-nosed monkeys (Rhinopithecus), we analysed ten mandibular measurements by principal components analysis (PCA), and examined scaling patterns. The results provided by the PCA illustrated differences due to size among the cercopithecoids and the relationship between colobines (Trachypithecus and Rhinopithecus) and cercopithecines, in which macaques (Macaca) are included. Allometric analysis indicated that, biomechanically, there is not a marked difference between macaques and leaf-eating monkeys. This may be associated with the fact that both share some similar ecology and niches in south and southwest China. The snub-nosed monkeys exhibit a significantly more robust mandible, evident in the symphysis, corpus, condyle, and masticatory momentum arm. This supports the hypothesis, based on the study of dental structure, that Rhinopithecus is a unique group in Asian Old World monkeys (OWMs) and has developed some unique characteristics in order to adapt to the tough food available in the severe cold climate of the Plateaux of Qinghai-Tibet, Yun-Gui and Qingling in China.
Resumo:
2008年5月,在广西壮族自治区靖两县禄洞村珠江水系采集到一批条鳅标本.经鉴定,为云南鳅属(Yunnanilus)-新种.新种靖西云南鳅(Yunnanilus jinxiensis)属于侧纹云南鳅种组(Yunnanilus pleurotaenis group).但新种全身除胸腹部外被有鳞片;侧线较长,具有15-20个侧线管孔;背鳍分枝鳍条8;胸鳍分枝鳍条13-14;鳔两室,后室发达;尾鳍凹形;体长为体高的3.9-_4.6倍,为头长的4.1-4.4倍,为尾柄高的7.5-9.0倍;头长为眼径的5.5-6.7倍,为眼间距的2.2-2.4倍等特征,可将新种与该种组内的其他种类相区分.
Resumo:
2006年10月-2007年4月采用瞬时扫描取样法对云南省昭通市大山包黑颈鹤国家级自然保护区内越冬的黑颈鹤(Grus nigricollis)种群进行了越冬时间分配和日间活动节律的研究.取食是黑颈鹤越冬期间最主要的行为,占(53.05±4.93)%,其次为警戒(18.75±2.65)%、搜寻00.38±1.34)%和休整(10.32±4.93)%,其余行为依次为:行走(4.901±1.59)%、飞行(1.70±0.38)%、其他(0.55±0.41)%、争斗(0.36_±0.25)%.黑颈鹤的出飞时间与日出时间、飞回时间与日落时间分别具有显著的正相关和负相关关系.越冬期间黑颈鹤日间各时间段(1h)(09:00-18:00)和各月份间(2006.11-2007.03)行为差异极显著(P<0.05),并呈现出上午和下午取食双峰、中午休息高峰的规律性变化.气温高时黑颈鹤增加休整时间减少取食时间;气温低时则减少休整时间增加取食时间.偏相关分析说明:环境温度独立地对越冬时间分配产生影响,湿度通过温度对黑颈鹤越冬时间分配产生相反的影响.
Resumo:
The present work deals with the biological study of the squid Illex illecebrosus argentinus of the Buenos Aires area (Argentina) in the southwest Atlantic ocean. According to recent research (Voss, pers. comm.) the squid obtained in commercial fishing in the waters off Buenos Aires Province (Castellanos), which in proper of the S.W. Atlantic. The material studied comes from commercial fishing done in in two sectors: one ranging from 36~' to 37~' S, and the other from 39~' to 42~' S in latitude, while both extend from 55~' to 62~' W in longitude. The fishing area varies during the years, being located more towards the North in summer and more towards the South in winter, following the fishing of hake. The number of individuals studied was 186. Their total length ranged from 195 mm to 670 mm for both sexes. The sampling showed that the males had lesser length and weight than the females: that is, a secondary sexual dimorphism was observed. At the length of 240 mm the squid reaches its sexual maturity. Sexual activity is observed the year around, but not simultaneously for the whole population, that is to say, spawning does not take place en masse but, on the contrary, it occurs during a prolonged period. In summer, from December to March, the greatest spawning period is observed. This takes place in the same habitat for the whole squid population. The squid herein studied is a cold water species, the water temperature ranging from 5~' to 12~' C in the sites of the largest catches. The squid is caught at depths ranging from 7 to 250 meters with a trawl net. In Patagonian waters, somewhat smaller individual are caught with 'poteras' at depths ranging from 1 to 8 fathoms.
Resumo:
The paper is based on qualitative properties of the solution of the Navier-Stokes equations for incompressible fluid, and on properties of their finite element solution. In problems with corner-like singularities (e.g. on the well-known L-shaped domain) usually some adaptive strategy is used. In this paper we present an alternative approach. For flow problems on domains with corner singularities we use the a priori error estimates and asymptotic expansion of the solution to derive an algorithm for refining the mesh near the corner. It gives very precise solution in a cheap way. We present some numerical results.
Resumo:
用远紫外CD谱研究了湖南产尖吻蝮蛇毒的两个出血毒素(DaHT-1、DaHT-2)的溶液构象, 计算得DaHT-1的#alpha#螺旋、#beta#折叠、无规卷曲的含量分别为36.9%, 35.5%, 27.6%; DaHT-2的#alpha#螺旋、#beta#折叠、无规卷曲分别为23.4%, 31.3%, 45.3%。随pH的增大或减小。温度和pH对CD谱的影响相似。0.02mol/L EDTA便导致两个出血毒素呈极度的无序状态。胰蛋白酶不影响它们的出血活性。图4表4参10