Maturity, ovarian cycle, fecundity, and age-specific parturition of black rockfish (Sebastes melanops)

From 1995 to 1998, we collected female black rockfish (Sebastes melanops) off Oregon in order to describe their basic reproductive life history and determine age-specific fecundity and temporal patterns in parturition. Female black rockfish had a 50% probability of being mature at 394 mm fork length and 7.5 years-of-age. The proportion of mature fish age 10 or older significantly decreased each year of this study, from 0.511 in 1996 to 0.145 in 1998. Parturition occurred between mid-January and mid-March, and peaked in February. We observed a trend of older females extruding larvae earlier in the spawning season and of younger fish primarily responsible for larval production during the later part of the season. There were differences in absolute fecundity at age between female black rockfish with prefertilization oocytes and female black rockfish with fertilized eggs; fertilized-egg fecundity estimates were considered superior. The likelihood of yolked oocytes reaching the developing embryo stage increased with maternal age. Absolute fecundity estimates (based on fertilized eggs) ranged from 299,302 embryos for a 6-year-old female to 948,152 embryos for a 16-year-old female. Relative fecundity (based on fertilized eggs) increased with age from 374 eggs/g for fish age 6 to 549 eggs/g for fish age 16.

On the unknown postlarval stages of the garfish, Tylosurus strongylurus (Van Hasselt) and the seapike, Sphyraena jello Cuvier

Unknown larval stages of Tylosurus strongylurus and Sphyraena jello have been traced from Vellar Estuary, Porto Novo (lat. 11 degree 29'N; long. 79 degree 46' E). Descriptions of different stages (7-17.5 mm T. strongylurus, and 18 and 22.5 mm S. jello) are given. A thorough ichthyoplankton survey for 2 years (Nov. 1977-Oct. 1979) in the estuary revealed that these larvae were very rare in the estuary and were caught on the occasion (Nov. 1978) only.

Effects of artificial feeds on production of fishes in polyculture

A study on the effects of artificial feeds on the growth and production of fishes in polyculture in 6 ponds along with some limnological conditions was conducted. Species of Indian and Chinese major carps (Labeo rohita, Catla catla, Cirrhinus mrigala, Hypophthalmicthys molitrix) and catfishes (Clarias batrachus, Clarias gariepinus) were stocked in 6 ponds. Stocking rate in both cases were 32044 fingerlings per hectare. Ratio of species of Rui:Catla:Mrigal:Silver carp:African Magur:Local Magur=25%:25%:5%:25%:14%:6%. Fertilization and artificial feeds were given in 3 ponds (treatment I) and only fertilization was done in other 3 ponds (treatment II). Average yield/ha/yr was 7.903 m.ton in case of fertilization and artificial feeding application and 3.374 m.ton in case of only fertilization application. Urea, TSP and cow dung were applied fortnightly at the rates of 400 kg/ha/yr, 2000 kg/ha/yr and 4000 kg/ha/yr respectively. Wheat bran, rice bran and mustard oil cake were given daily as an artificial feed in treatment I. Whereas treatment II was conducted without any artificial feed. Ratio of artificial feed was wheat bran:rice bran:oil cake=2:2:1 (by wt). Absence of artificial feed in 3 ponds under treatment II seriously affected the growth and production of fish.

Transitions in the erosive wear behavior of a glass-ceramic

The mechanisms of material removal were investigated during the erosive wear of a glass-ceramic. The effects of erodent particle shape, velocity and angle were studied. Single impacts and incremental erosion tests were performed, to study the development of surface features and to elucidate the mechanisms of material removal. It was found that transitions in mechanism occurred which depended on the particle shape, impact velocity and impact angle. The mechanisms of material removal, for erosion by silica sand, changed from fine scale fracture and plastic processes below a transition point to large-scale cracking of the surface above. Spherical glass beads caused wear dominated by fatigue, with a very strong dependence of wear rate on the impact conditions. This work indicates that laboratory erosion testing of glass-ceramic and other brittle materials should reflect the conditions present in practice, and that account must be taken of possible changes in wear mechanisms.

RANS-URANS in axial compressor, a design methodology

Turbomachinery flows are inherently unsteady. Until now during the design process, unsteadiness has been neglected, with resort merely to steady numerical simulations. Despite the assumption involved, the results obtained with steady simulations have been used with success. One of the questions arising in recent years is can unsteady simulations be used to improve the design of turbomachines? In this work the numerical simulation of a multi-stage axial compressor is carried out. Comparison of Reynolds averaged Navier-Stokes (RANS) and unsteady Reynolds averaged Navier-Stokes (URANS) calculation shows that the unsteadiness affects pressure losses and the prediction of stall limit. The unsteady inflow due to the wake passing mainly modifies the losses and whirl angle near the endwalls. The computational cost of the fully unsteady compared with a steady simulation is about four times in terms of mesh dimension and two orders of magnitude as number of iterations. A mixed RANS-URANS solution has been proposed to give the designer the possibility to simulate an unsteady stage embedded in a steady-state simulation. This method has been applied to the simulation of a four-stage axial compressor rig. The mixed RANS-URANS approach has been developed using sliding and mixing planes as interface conditions. The rotor-stator interaction has been captured physically while reducing the computational time and mesh size.

A novel serine protease inhibitor from Bungarus fasciatus venom

By Sephadex G-50 gel filtration, cation-exchange CM-Sephadex C-25 chromatography and reversed phase high-performance liquid chromatography (HPLC), a novel serine protease inhibitor named bungaruskunin was purified and characterized from venom of Bungarus fasciatus. Its cDNA was also cloned from the cDNA library of B. fasciatus venomous glands. The predicted precursor is composed of 83 amino acid (aa) residues including a 24-aa signal peptide and a 59-aa mature bungaruskunin. Bungaruskunin showed maximal similarity (64%) with the predicted serine protease inhibitor blackelin deduced from the cDNA sequence of the red-bellied black snake Pseudechis porphyriacus. Bungaruskunin is a Kunitz protease inhibitor with a conserved Kunitz domain and could exert inhibitory activity against trypsin, chymotrypsin, and elastase. By screening the cDNA library, two new B chains of beta-bungarotoxin are also identified. The overall structures of bungaruskunin and beta -bungarotoxin B chains are similar; especially they have highly conserved signal peptide sequences. These findings strongly suggest that snake Kunitz/BPTI protease inhibitors and neurotoxic homologs may have originated from a common ancestor. (c) 2007 Elsevier Inc. All rights reserved.

云南哀牢山平河黑长臂猿栖息地乔木结构分析

采用样方方法对栖息于云南省哀牢山平河(E 101°17′16.1″,N 24°20′09.5″,海拔2 600 m)的黑长臂猿(Nomascus concolor)栖息地乔木层结构进行了调查.调查中共记录到乔木57种隶属于23科37属;木质藤本植物9种隶属于6科8属.优势科主要为杜鹃花科(Ericaceae)、木兰科(Magnoliaceae)、山茶科(Theaceae)和壳斗科(Fagaceae)植物.主要树种重要值排序表明,露珠杜鹃(Rhododendron irroratum)为该地区最主要的优势种,在各坡位中均有广泛分布.乔木的多样性指数、均匀度指数在沟底明显降低,而乔木1层和2层所占的比例以及木质藤本的平均多度均随着坡位的下降而升高.与其他地区的长臂猿相比,哀牢山黑长臂猿的活动程度较低(10-22 m),果实性食物种类较少.

“鱇(鱼良)白鱼人工增殖技术和种群恢复研究”取得进展

由中国科学院昆明动物研究所、玉溪市水电局、抚仙湖管理局共同承担的“鱇(鱼良)白鱼人工增殖技术和种群恢复研究”项目是中国科学院昆明分院和玉溪市政府拟定的院、市合作项目之一. 该项目于1999年4月正式启动. 为顺利开展本项目的研究, 以参加单位的有关科技人员的技术骨干, 成立了“鱇(鱼良)白鱼人工增殖技术和种群恢复研究”实验站。