107 resultados para COSMIC-RAYS


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A new species of hillstream loach genus Balitora Gray is discovered from Nanting River drainage, which drains to Salween, Yongde County, Yunnan, China. Balitora nantingensis can be distinguished from B. lancangjiangensis by a triangle-like blotch in nape absent vs. present; area from halfway of pelvicfin ray to anus covered by scales vs. no scales in this area; the first pectoral ray thickened vs. not; posterior end of pelvic-fin surpasses middle point from posterior end of pelvic-fin base to anal-fin origin vs. the end from posterior extremity of pelvic-fins to anus; fewer lateral line scales, 59-64 vs. 66-70; slightly longer head, SL 4.2-5.1 (4.6) times of HL vs. 5.0-5.9 (5.4); slightly larger eyes, HL 4.0-6.4 (5. 1) times of eye diameter vs. 5.5-7.5 (6.3). Balitora nantingensis can be distinguished from B. burmanica by body rounded vs. slender in dorsal view; pointed snout vs. blunt in dorsal view; a deeper body, body depth 12.5-16.9% of SL vs. 10-12%; a deeper caudal-peduncle, length of caudal-peduncle 2.0-2.8 times of its depth vs. 3.0-4.2; a shorter caudal-peduncle, 14.3-15.6% of SL vs. 16-21%; the average ratio of body width at pelvic-fin origin and distance between inner pelvic-fin base 2.0 vs. 3.4; body width 1.1-1.5 times of body depth vs. 1.5-1.6; posterior end of pelvic-fin almost one or slight more than one eye diameter from anus vs. closet to anus; outside rays of pelvic-fin extend more posteriorly than inside rays and make posterior outline of fin acclivitous and straight vs. the outside ones almost equal to the inside ones and make the fin slightly convex.

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Schistura cryptofasciata is distinguished from its congeners by following combination characters: lateral line complete; 8(1)/(2) branched dorsal-fin rays; 9+8 branched caudal-fin rays; no sexual dimorphism; 8-11 indistinct bars, wider than interspaces; caudal-peduncle length 44.1-16.5% standard length, 68.1-90.4% dorsal head length; anterior portion of body scaleless; air bladder entirely embedded in bony capsule; lateral head length 104-122% dorsal head length; lower jaw with a notch at symphysis; lower lip completely interrupted; interorbital width 1.9-2.2 times eye diameter; pelvic-fin origin ventral to dorsal-fin origin; anus 1.0-1.5 eye diameters in front of anal-fin origin; the widest part of black basal caudal bar is the midlateral, and then the upper and lower ends.

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A new blind loach of Triplophysa Rendahl 1933 was collected from a subterranean pool in a cave at Wulong County, Chongqing City, China, in November 2002. The new species, named Triplophysa rosa sp. nov., can be distinguished from its congeners by the following unique characters: eyes vestigial; 9 branched dorsal-fin rays; 12 branched pectoral-fin rays; 7 branched pelvic-fin rays; 6 branched anal-fin rays; 7 + 7 branched caudal-fin rays; distal margin of dorsal-fin concave; tip of pelvic-fin surpasses vertical level of anus; caudal-fin deeply forked; whole body scaleless and colourless. (c) 2005 The Fisheries Society of the British Isles.

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A new species of Metahomaloptera, M. longicauda, is described from the lower Jinsha River, China. The new species is distinguished from other species of Metahomaloptera by the following combination of characters: pectoral fin with 11 15 branched rays, tip

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A new species of the genus Paracobitis, Paracobitis nanpanjiangensis is described from tributaries of the Nanpanjiang River drainage in China. It is distinguished from its congeners, except P. oligolepis and P. wujiangensis, by body scaleless or with rudimentary scales (caudal peduncle with several deeply embedded scales). It can be differentiated from P. wujiangensis by the complete lateral line (vs. incomplete), lower dorsal crest reaching the vertical of origin of anal fin (vs. shorter and higher dorsal crest not reaching the base of anal fin). It is distinguished from P. oligolepis by the following characters: branched dorsal fin with 81/2 (a few 91/2) rays (vs. 91/2), interspaces between bars in front of dorsal fin conspicuously thinner than those behind (vs. vermiform markings), dorsal head without vermiform markings or obscure (vs. clearly vermiform markings on dorsal head), vertebrae 4 + 36-38 (vs. 4 + 39-41).

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Two new species and a new record of Sinogastromyzon are described from Lixianjiang River of Yunnan province, China. Sinogastromyzon lixianjiangensis, new species, can be distinguished from its congeners by the following characters: pectoral fin with XIII-XIV, 15-17 rays; pelvic fin with X-XI, 10-12 rays; 60-65 lateral-line scales; no scales on the dorsum of paired fins or the region between axilla of pectoral fin and pelvic-fin origin; tip of pelvic fin close to anus; tip of anal fin close to caudal-fin base; anal-fin origin nearer to the caudal-fin base than to the posterior pelvic-fin base; anus nearer to anal-fin origin than to the posterior pelvic-fin base; dorsal side of the body with 9-11 black blotches. Sinogastromyzon macrostoma, new species can be distinguished from its congeners by the following characters: pectoral fin with XII-XIV, 12-15 rays; pelvic fin with VII-IX, 11-13 rays; 48-56 lateral-line scales; mouth extremely big, slightly arched; no scales on the dorsum of paired fins or the region between axilla of pectoral fin and pelvic-fin origin; tip of pelvic fin far beyond anus; tip of anal fin far from caudal-fin base; anal-fin origin about midway between the posterior pelvic-fin base and caudal-fin base; anus nearer to posterior pelvic-fin base than to anal-fin origin; dorsal side of the body uniformly gray, without regular blotches in formalin preserved specimen. Sinogastromyzon cf. multiocellum is firstly recorded in China.

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Pseudobagrus fui Miao is a valid bagrid species that can be separated from all its congeners in having 27-33 anal-fin rays. Among the species of Pseudobagrus, it forms part of a group of approximately 20 species putatively characterized by having a smooth anterior margin of the pectoral-fin spine and short maxillary barbels not extending to the base of the pectoral-fin spine. Pseudobagrus fui, together with P. nitidus and P. vachelli, can be differentiated from all other fork-tailed species of this group by having no fewer than 20 branched anal-fin rays, the posterior end of the anal-fin base posterior to the vertical through the posterior end of the adipose-fin base, and anal-fin base longer than the adipose-fin base. It further differs from P. nitidus in having a gas bladder without beaded lateral and posterior margins, and from P. vachelli in having short maxillary barbels not extending to the base of the pectoral-fin spine. Pseudobagrus fui is currently known from the main stream of the upper Yangtze River and its tributaries, the Min River, Jialing River, Tuo River, Wu River and Chishui River in Sichuan Province, Guizhou Province, and the Chongqing City. The identity and nomenclature of Pseudobagrus nitidus is also discussed.

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Metzia longinasus, a new cultrine cyprinid species from the Hongshui-He River of the Pearl River drainage in Guangxi Province, southern China, is described here. It can be distinguished from all other congeners by having a combination of the following characters: a superior mouth, 43 or 44 lateral-line scales, a long head (length 27.2-30.8% of standard length), a long snout (length 31.7-37.0% of head length), 10 or 11 branched anal-fin rays, and no longitudinal black band extending along each side of body from the extremity of the gill opening to caudal-fin base.

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Pseudobagrus brachyrhabdion sp. nov., from the Yuan Jiang and Xiang Jiang of the middle Yangtze River drainage in Hunan and Guizhou Provinces, South China, is described herein. It is distinguished from all other Pseudobagrus species with a truncate or slightly emarginated caudal fin by an unique combination of the following characters: supraoccipital plate and nuchal plate broadly interspaced and covered with skin; nasal barbels only at most reaching anterior margin of eye; maxillary barbels reaching slightly beyond posterior margin of eye; outer mandibular barbels extending to posterior margin of eye; dorsal fin with a somewhat convex distal margin, origin nearer to pectoral-fin insertion than to pelvic-fin insertion; dorsal-fin spine shorter than pectoral spine, with a somewhat serrated posterior margin; pectoral-fin spine with a smooth anterior margin; anal fin with 20-23 rays, base length 23.8-32.0% of standard length, posterior end of anal-fin base anterior to posterior end of adipose fin base; no longitudinal black band extending along flank; eyes large, diameter 16.3-23.7% of head length; and number of vertebrae 5 + 43-46.

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Triplophysa lixianensis, a new nemacheiline loach species, is described from the Min Jiang of the upper Yangtze River drainage in Sichuan Province, South China. It can be separated from all other species of Triplophysa by having a unique combination of the following characters: posterior chamber of gas bladder greatly reduced or absent; caudal peduncle columnar with a roughly round cross- section at its beginning; anterior edge of lower jaw completely exposed or uncovered by lower lip; intestine short, forming a zigzag loop below stomach; dorsal- fin origin closer to caudal- fin base than to snout tip; pelvic fin inserted anterior to dorsal- fin origin; snout length 50.6 - 57.5 % of head length; eye diameter 12.3 15.4 % of head length; caudal peduncle length 25.1 - 27.1 % of standard length; anal fin with five branched rays; lower lip greatly furrowed with two thick lateral lobes; and body smooth or scaleless.

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The type species of the cyprinid genus Sinilabeo was misidentified as Varicorhinus tungting, and the species under the generic name belong to Bangana and Linichthys. In order to make Sinilabeo available, its type species is fixed under Article 70.3.2 of the 1999 edition of the International Code of Zoological Nomenclature as S. hummeli, a new species herein described from the upper Yangtze River basin in Chongqing City and Sichuan Province, South China. A re-definition is provided for Sinilabeo. It resembles Qianlabeo in having an upper lip only present in the side of the upper jaw and uncovered by the rostral fold, but missing in the median part of the upper jaw that, instead, bears a thin, flexible, and cornified sheath, covered by the rostral fold, a character that can separate both from all other existing genera of Asian labeonins. However, Sinilabeo is distinguished from Qianlabeo in the presence of a rostral fold disconnected from the lower lip; a broadly interrupted postlabial groove only restricted to the side of the lower jaw; an upper lip, which is only present in the side of the upper separated from it by a groove; 9-10 branched dorsal-fin rays; two pairs of tiny maxillary barbels.

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The taxonomic problem of the cyprinid species of genus Spinibarbus, occurring in southern China and northern Vietnam, was resolved on the basis of molecular and morphological analyses. Spinibarbus caldwelli and Spinibarbus hollandi have a smooth posterior edge of the last unbranched dorsal fin ray among species in the genus. Spinibarbus caldwelli is currently regarded as a junior synonym of S. hollandi because of ambiguities in diagnostic characters. In this article, 11 mtDNA cytochrome b sequences of Spinibarbus specimens were analyzed together with Barbodes gonionotus and Puntius conchonius as outgroups. Our results showed that specimens identified as S. hollandi from Taiwan were different from those from the Asian mainland at a high level of genetic divergence (0.097-0.112), which is higher than that between the two valid species, S. sinensis and S. yunnanensis ( 0.089), and suggested that Taiwan specimens should be considered as a different species from the Asian mainland one. In a molecular phylogenetic analysis, the sister-group relationship between Taiwan specimens and the Asian mainland specimens was supported strongly by a high confidence level ( 100% in bootstrap value). Further analysis of morphological characters showed that overlap of diagnostic characters is much weaker than previously suggested. Taiwan specimens had 8 branched rays in the dorsal fin, whereas those from the mainland had almost 9-10. The molecular and morphological differences suggest S. caldwelli to be valid. The molecular divergence shows the genetic speciation of S. hollandi and S. caldwelli might have occurred 5.6-4.9 million years ago; the former could be a relict species in Taiwan, and the latter dispersed in the Asian mainland.

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Sinibrama longianalis, a new cyprinid species from the Wu Jiang (upper Yangtze River basin) in Guizhou, China is distinguished from other congeners in having the following combination of characters: last simple dorsal-fin ray well-ossified; a snout shorter than eye diameter; eye diameter 27.1-31.6% HL; lateral line scales 56-64 (mean 59.5); circumpeduncular scales 18-21; anal fin with 24-28 (mean 25.2) branched rays, originating opposite to or slightly in advance of posterior end of dorsal-fin base, basal length 27.0-31.1% SL; pectoral fin reaching to or slightly beyond pelvic-fin insertion.

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Procedures to improve somatic cell nuclear transplantation in fish were evaluated. We reported effects of nonirradiated recipient eggs, inactivated recipient eggs, different combinations between recipient eggs and donor cells, duration of serum starvation, generation number, and passage number of donor cells on developmental rates of nuclear transplant (NT) embryos. Exposure to 25,000 R of gamma-rays inactivated recipient eggs. Single nucleus of cultured, synchronized somatic cell from gynogenetic bighead carp (Aristichthys nobilis) was transplanted into nonirradiated or genetically inactivated unfertilized egg of gibel carp (Carassius auratus gibelio). There was no significant difference in developmental rate between nonirradiated and inactivated recipient eggs (27.27% vs. 25.71%, respectively). Chromosome count showed that 70.59% of NT embryos contained 48 chromosomes. It showed that most NT embryos came from donor nuclei of bighead carp, which was supported by microsatellite analysis of NT embryos. But 23.53% of NT embryos contained more than 48 chromosomes. It was presumed that those superfluous chromosomes came from nonirradiated recipient eggs. Besides, 5.88% of NT embryos were chimeras. Eggs of blunt-snout bream (Megalobrama amblycephala) and gibel carp were better recipient eggs than those of loach (Misgurnus anguillicaudatus) (25% and 18.03% vs. 8.43%). Among different duration of serum starvation, developmental rate of NT embryos from somatic nuclei of three-day serum starvation was the highest, reaching 25.71% compared to 14.14% (control), 20% (five-day), and 21.95% (seven-day). Cultured donor cells of less passage facilitated reprogramming of NT embryos than those of more passage. Recloning might improve the developmental rate of NT embryos from the differentiated donor nuclei. Developmental rate of fourth generation was the highest (54.83%) and the lowest for first generation (14.14%) compared to second generation (38.96%) and third generation (53.01%). (C) 2002 Wiley-Liss, Inc.

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Mode characteristics of a square microcavity with an output waveguide on the middle of one side, laterally confined by an insulating layer SiO2 and a p-electrode metal Au, are investigated by two-dimensional finite-difference time-domain technique. The mode quality (Q) factors versus the width of the output waveguide are calculated for Fabry-Peacuterot type and whispering-gallery type modes in the square cavity. Mode coupling between the confined modes in the square cavity and the guided modes in the output waveguide determines the mode Q factors, which is greatly influenced by the symmetry behaviors of the modes. Fabry-Peacuterot type modes can also have high Q factors due to the high reflectivity of the Au layer for the vertical incident mode light rays. For the square cavity with side length 4 mu m and refractive index 3.2, the mode Q factors of the Fabry-Peacuterot type modes can reach 10(4) at the mode wavelength of 1.5 mu m as the output waveguide width is 0.4 mu m.