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911.
Aim To study (1) the large-scale distribution patterns of freshwater fishes in the Western Ghats of India; (2) the endemism and uniqueness of the fishes in various zones; and (3) the threat status of fishes by categorizing them under low risk (LR), vulnerable (VU), endangered (EN) and critically endangered (CR). Location The Western Ghats of India. Methods The scientific literature describing the freshwater fishes of the Western Ghats was reviewed. Data describing the lists of the species were extracted and complied. The species accumulation curve was plotted using Michaelis–Menten-like equation. The Western Ghats was divided into six zones and similarity of the species was calculated using Jacquard's index. Results Literature to date records 288 species belonging to 12 orders, 41 families and 109 genera, of which 118 species are endemic and 51 are unique. However, the species accumulation curve shows that there might be 345 species in this region, indicating that 16% species have not been recorded to date. An analysis of the distribution pattern of fishes in the Western Ghats suggests that the southern region is more diverse than the northern and central regions. The southern region shows high endemism and high uniqueness while the northern region shows high endemism but less uniqueness. The similarity index between the zones indicates that as the distance between the zones increases similarity decreases. The status of 105 of 288 species was not known due to data deficiency but among the remaining 183 species, 58 species were categorized as LR, 41 as VU, 54 as EN, 24 as CR while the remaining six species were introduced. Conclusions The distribution patterns of fishes in the Western Ghats are discussed in accordance with the geography of Western Ghats, its climatic conditions and ‘Satpura Hypothesis’. The threat status of fishes found in Western Ghats suggests that at least 41% of fish fauna is threatened by either being VU, EN or CR. Implication of potent conservation measures is necessary to conserve the fish fauna of Western Ghats.  相似文献   
912.
913.
Population declines of Steller sea lions ( Eumetopias juhatus ) in western Alaska (west of 144°W) may be a result of reduced juvenile survival. We used satellite telemetry to study the at-sea distribution and movement patterns of pup (1.6–11.9 mo) and juvenile (12.0–35.1 mo) Steller sea lions. We studied trip distance, duration, and interhaul-out movements of sea lions in relation to age, sex, and month of year in the decreasing western population (WP; Prince William Sound, Kodiak, Aleutian Islands, Alaska) and the increasing eastern population (EP; Southeast Alaska). We deployed 103 satellite transmitters (29 WP; 74 EP) on sea lions between 1998 and 2001. Round trip distance and duration increased with age, trip distance was greater in the WP than the EP, trip duration was greater for females than males, and haul-out use was clustered. Changes in round trip distance and duration occurred from April to June for all age classes studied indicating that the annual timing of weaning may be less variable than the age of weaning. Overall, 90% of round trips were ≤ 15 km from haul-outs and 84% were <20 h, indicating nearshore areas adjacent to haulouts are critical to the developing juvenile.  相似文献   
914.
Aim  This work aimed to assess changes in the number of suitable habitats and habitat occupancy by Micropterix calthella (L.) moths (Lepidoptera, Micropterigidae) in the city of St Petersburg between 1989 and 2005.
Location  The city of St Petersburg, Russia.
Methods  The study compares results of the survey conducted on 9–12 June 2005 with data collected in 1989 and is based on the assessment of the quality and occupancy of 103 habitats that were found potentially suitable for M. calthella in 1989. If habitats contained wet microsites with undisturbed litter and dense field layer vegetation with a high abundance of flowering Ranunculus sp., they were considered potentially suitable for M. calthella ; in these habitats, moths were searched for on flowers of Ranunculus – visually and/or by extensive sweep-netting.
Results  Both the number of habitats suitable for M. calthella and the number of habitats occupied by this species decreased since 1986 from 103 to 72 and from 58 to 34, respectively. The disappearance of habitats was primarily due to the building of residential blocks within the city (16 sites) and railway renovation (10 sites), while changes in habitat management, primarily in parks and recreation zones (five sites), were less important. The average distance from the city centre to the nearest population of M. calthella increased from 8.7 ± 1.5 to 12.9 ± 3.0 km (mean ± SE).
Main conclusion  The data for 2005 fit the prediction that M. calthella moths, which are unable to re-colonize potentially suitable habitats due to their low migratory ability, will disappear from the city. At the present rate of extinction, this process may take some 20–30 years to complete (or nearly complete).  相似文献   
915.
ABSTRACT. Myrionecta rubra, a ubiquitous planktonic ciliate, has received much attention due to its wide distribution, occurrence as a red tide organism, and unusual cryptophyte endosymbiont. Although well studied in coastal waters, M. rubra is poorly examined in the open ocean. In the Irminger Basin, North Atlantic, the abundance of M. rubra was 0–5 cells/ml, which is low compared with that found in coastal areas. Distinct patchiness (100 km) was revealed by geostatistical analysis. Multiple regression indicated there was little relationship between M. rubra abundance and a number of environmental factors, with the exception of temperature and phytoplankton biomass, which influenced abundance in the spring. We also improve on studies that indicate distinct size classes of M. rubra; we statistically recognise four significantly distinct width classes (5–16, 12–23, 18–27, 21–33 μm), which decrease in abundance with increasing size. A multinomial logistic regression revealed the main variable correlated with this size distribution was ambient nitrate concentration. Finally, we propose a hypothesis for the distribution of sizes, involving nutrients, feeding, and dividing of the endosymbiont.  相似文献   
916.
The problem of testing treatment difference in the occurrence of a safety parameter in a randomized parallel‐group comparative clinical trial under the assumption that the number of occurrence follows a zero‐inflated Poisson (ZIP) distribution is considered. Likelihood ratio tests (LRT) for homogeneity of two ZIP populations are derived under the hypotheses that (i) there is no difference in inflation parameters, (ii) there is no difference in non‐zero means; and (iii) there is no difference in both inflation parameters and non‐zero means. Approximate formulas for sample size calculation are also obtained for achieving a desired power for detecting a clinically meaningful difference under the corresponding alternative hypotheses. An example concerning the assessment of the gastrointestinal (GI) safety in terms of the number of erosion counts of a newly developed compound for the treatment of osteoarthritis and rheumatoid arthritis is given for illustration purpose (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
917.
In two regions of British Columbia, small and medium-sized shoals of pre-spawning Pacific herring Clupea harengus pallasi were most numerous and occurred as neighbours more frequently than would be expected by chance. Herring displayed a typical diurnal vertical migration, although shoals in the Central Coast were more evenly distributed through the water column during the day than those in the Strait of Georgia. As maturation progressed, shoals were found in shallower water, more densely packed and vertically extended in shape. In the Strait of Georgia, shoals were considerably larger, and positioned relatively deeper in the water column. Very large (>5000 t) shoals were found at specific locations characterized by high water exchange. Large shoals may act as an anti-predator strategy to the abundant sealions and birds. Moreover, staying deep in the water column, and associating with dips in the sea bed, reduces predation risk and confers energy savings through hydrodynamic advantage. Smaller, denser, vertically extended, travelling shoals, prevalent during the later stages of gonad maturation, were similar in nature to labile spherical shoals observed in the Central Coast at different locations each day. Both these shoal types may benefit from synchrony and co-ordination when evading predators that is not possible for larger shoals. The more highly clustered distribution of shoals in the Central Coast is presumed to be linked to their tight association with rock outcroppings typical of this region.  相似文献   
918.
目的:探讨不同临床病理特征的乳腺非特殊型浸润性癌的分子亚型分布特点。方法:回顾性分析309例乳腺非特殊型浸润性癌患者的临床资料,根据患者年龄、绝经情况、组织学分级和淋巴结转移情况分组,每组再根据免疫组化雌激素受体(ER)、孕激素受体(PR)、人类表皮生长因子受体2(HER-2)结果分为4种不同的分子亚型,分析各组中不同分子亚型的分布特点。结果:309例乳腺非特殊型浸润性癌中Lumina A型为137例(44.3%),Lumina B型为64例(20.7%),HER-2/neu型为63例(20.4%),basal cell-like型为45例(14.6%)。不同年龄段、绝经与否、不同组织学分级和淋巴结转移情况患者的分子亚型差异均具有统计学意义(P0.05)。结论:非特殊型浸润性癌的分子亚型以Luminal A型为主,其中异型性高,转移广泛的basal cell-like型的年龄分布呈现年轻化趋势。  相似文献   
919.
《环境昆虫学报》2015,37(4):735-741
剪枝象属Cyllorhynchites Voss隶属于齿颚象科Rhynchitidae齿颚象亚科Rhynchitinae齿颚象族Rhynchitini,但其属名在国内外使用较为混乱。此外,该属的常见种类栗实剪枝象Cyllorhynchites cumulatus Voss与橡实剪枝象C.ursulus Roelofs等常被误认为隶属于同族的Mecorhis或Mechoris属。通过查阅相关文献和我国多地所采集的标本,本文旨在厘清剪枝象的有效学名,并对栗实剪枝象和橡实剪枝象的形态和生态特征进行了补充,以便提供更准确的鉴别特征。结果如下:(1)剪枝象属拉丁学名为Cyllorhynchites Voss,而非Mecorhis Billberg或Mechoris。栗实剪枝象与橡实剪枝象的中文学名以寄主命名。(2)栗实剪枝象成虫身体蓝黑色,鞘翅上的白色短柔毛稀疏且行纹明显。幼虫体长6.0-9.0 mm,触角感觉器长矛状;额背面的刚毛仅有2对,标记为fs4,fs5;头盖背面无刚毛;上唇及唇基较窄。分布于黄河以南,主要以栗属植物为寄主。在安徽金寨,栗实剪枝象的羽化期在5月底-6月底,成虫羽化后即可交配、产卵,产卵期和剪枝期在6月-7月上旬。橡实剪枝象成虫身体黑褐色,但足为褐色。鞘翅上的黄色短柔毛较密且行纹不明显。幼虫体长8.0-10.0 mm,触角感觉器长圆锥状;额背面的刚毛仅有1对,标记为fs5;头盖背面的刚毛仅有1对,标记为des5;上唇及唇基较宽。广布中国南北和日本、朝鲜半岛,以栎属和青冈属植物为寄主。在四川都江堰,橡实剪枝象的羽化期在6月-7月。由于橡子尚未发育,其成虫羽化后需经历较长的营养补充期,产卵期和剪枝期在8月中旬-9月底。本研究澄清了过去关于剪枝象属的分类归属,并对两种常见剪枝象的形态和生态特征进行了深入比较,为生产上准确鉴别这些剪枝象种类提供参考。  相似文献   
920.
大洋臀纹粉蚧Planococcus minor Maskell和南洋臀纹粉蚧P.lilacinus Cockerell是我国有重要检疫意义的有害生物。这两种粉蚧从东盟进口水果口岸检疫中频繁截获,且已在广东、海南、云南等地发现大洋臀纹粉蚧入侵,这对我国热带、亚热带的水果和观赏植物等已构成严重威胁。本研究以大洋臀纹粉蚧和南洋臀纹粉蚧在国内外的分布数据为基础,利用Maxent生态位模型和Arc GIS对两种粉蚧在中国的潜在适生区进行预测。预测结果表明,大洋臀纹粉蚧和南洋臀纹粉蚧的适生区主要分布在长江流域以南地区,其适生区面积分别占全国面积的22.14%、18.17%,其中高度适生区域集中分布在广西、广东、云南、福建、四川、台湾、海南等地区,与我国热带水果的主要种植区域具有高度的一致性。大洋臀纹粉蚧已成功入侵,一旦南洋臀纹粉蚧传入便可迅速扩散蔓延,并对我国热带水果生产造成严重危害。因此,各口岸应加强对东盟进口水果的检验检疫,预防其新的进入和扩散。  相似文献   
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