Growth rates of Tilapia esculenta (Graham) and Tilapia zillii (Gervais) under cultivation in ponds at Nyegezi, Tanzania

Aquaculture in Tanzania is still on a subsistence level and most of the ponds are maintained as part time job. The ponds are too small, shallow and over crowded with stunted Tilapia spp. In the present paper the results of experiments conducted in ponds at Nyegezi with T. esculenta and T. zillii are presented. This was part of an overall project of developing techniques of fish cultures with Tilapia under the limited existing conditions at Nyegezi. In a mono - species culture experiement with Tilapia zillii in nine month's time an average size of 172.8 mm/115.0 g was attained. In another experiment with T. zillii and T. esculenta in thirteen month's time, T. zillii attained an average size of 180.2mm/106.6 g and T. esculenta 193.6 mm/118.8 g. In another experiment with intensive feeding schedule an average size of 179.3 mm/126.6 g was attained by T. zillii and 191.0 mm/125.0 g by T. esculenta in four month's time. A locally prepared supplimentary feed with local Brewery Waste and Fish Meal (10:1) was readily accepted by both species of Tilapia. T. zillii voraciously fed on Cabbage leaves, Cauliflower leaves, Chinese cabbage leaves, Cassava leaves and on the common weed Comalina sp. Though all the items mentioned above were readily accepted by T. zillii feeding with Comaltna sp. was the easiest and most convenient because of its availability. In an intensive feeding experiment with vegetable leaves/Comalina sp. and the locally prepared supplimentary feed the fishes attained table size in four months time. Cement cistens of 5 X 3 X 1½ m size could be conveniently used for breeding both species of Tilapia. T. zillii had semi adhesive eggs and they were deposited on the sides of the cement wall. The number of young ones in a brood ranged from 160 to 314 in T. esculenta and 687 to 4,356 in T. zillii.

Exploring the process of whole system design

This paper explores the adoption of a whole system approach to a more sustainable and innovative design. A case study methodology was utilised to gain improved understanding of whole system design and those factors that substantially influence its success. The paper presents a framework of those factors including the requirement for trans-disciplinary skills, the dynamics of a flattened hierarchy and the need to identify relationships between parts of the system to ultimately optimise the whole. Knowing the factors that influence the process of whole system design provides designers with the knowledge necessary to more effectively work within, manage and facilitate that process. This paper uses anecdotes taken from operational cases, across design contexts, to demonstrate those factors. © 2010 Elsevier Ltd. All rights reserved.

Understanding luxury in the premium automotive industry

This paper summarises the findings of investigations to date in understanding what luxury and premiumness mean to the high-end automotive consumer. Existing writings on luxury and premiumness are considered. An exploratory study was carried out in two countries using 309 respondents and 18 prestige cars. A "stream of consciousness" approach was used to capture respondent's views on a selection of vehicles. The codified transcripts were used to identify key differences between the top and bottom rated vehicles, in terms of the nature and quantity of emotional responses elicited. This paper describes some of these key product differences that were self-reported to impact upon a luxury response. Finally, suggestions are made as to the next steps required for this research. © 2007 ACM.

草鱼野生和养殖群体间遗传变异的微卫星分析

运用微卫星标记对江苏境内草鱼(Ctenopharyngodon idella)一个野生群体(邗江群体)和两个养殖群体(淡水中心群体和无锡前洲群体)遗传多样性进行了分析.在10个座位中,每个座位检测到的等位基因数2～8个.有效等位基因数、多态信息含量、期望杂合度、平均表观杂合度均以邗江草鱼野生群体最高,分别为3.9、0.506 8、0.693 9、0.7;无锡前洲草鱼养殖群体最低,分别为2.2、0.179 6、0.523 5、0.528 6;淡水中心草鱼养殖群体各参数均介于两者之间,分别为3.5、0.290 2、0.541 8、0.542 9.以上结果表明:草鱼野生群体遗传多样性更为丰富,而草鱼养殖群体存在杂合度降低,遗传多样性下降的现象.邗江草鱼野生群体与淡水中心草鱼养殖群体和无锡前洲草鱼养殖群体间遗传分化系数分别为0.219和0.246,而两个草鱼养殖群体间遗传分化系数为0.034.这表明草鱼野生群体与草鱼养殖群体间分化严重,而草鱼养殖群体间分化微弱.各座位分化程度的χ2检验结果表明,10个座位中有GM18、MFW1-1、MFW1-2三个座位群体间分化达到极显著水平,GM03-2、MFW5两个座位群体间分化差异显著,其他座位分化不显著.针对每个座位对各群体进行Hardy-Weinberg平衡检验发现:由于草鱼养殖群体在GM03-1、GM03-2、GM18三个位点杂合子缺失,草鱼野生群体在位点GM19杂合子过剩而严重偏离平衡.实验表明:近交容易引起草鱼遗传多样性下降,纯合速度加快.

肝素钠树脂精制工艺的研究

利用D254树脂可以将原始粗品肝素钠的效价提高到179. 8 U SP U öm g, 进一步纯化可得201. 5 U SP U öm g 的精品, 其H2O 2 用量(1. 5% ) 和氧化时间(24 h) 均少于传统工艺, 产品光吸收和收率(85. 8% ) 最优。

杭州西湖浮游藻类变化规律与水质的关系

于2006～2007年对杭州西湖浮游藻类的种类及个体丰度进行初步研究,并依据《水和废水监测分析方法》对其水质现状进行了生物学评价。综合生物和理化指标数据,对杭州西湖的水质作一总体评估,并对西湖水中的物种多样性保护及水质的可持续利用提出了建议。共鉴定浮游藻类179种,其中蓝藻25种,隐藻1种,金藻3种,甲藻3种,黄藻5种,裸藻23种,硅藻41种和绿藻78种。分析了杭州西湖浮游藻类的组成和分布的特点,揭示出西湖浮游藻类的种类组成与西湖水质变化之间的关系。结果表明:藻类的组成和分布与水质变化规律基本吻合,西湖水

中科院水生生物研究所SCI收录论文分析报告

美国科学情报研究所编制的《科学引文索引》(SC I)所提供的分析数据是目前国际评价科研成果水平的通用参考标准,也是对研究单位或个人科研实力进行评价的一个重要依据。1991年以来的数据显示,水生所发表文章被SC I收录呈现不断上升态势。1991~1998年,水生所进入知识创新工程之前的7年中被SC I收录的文章总和仅为63篇;进入创新之后水生所被SC I收录的论文数量快速增长,一期创新阶段,水生所被SC I收录论文总数就达到179篇;二期创新4年中,水生所被SC I收录的论文更是突飞猛进地增长达到427篇,

不同念珠藻的提取物对酪氨酸酶活性的抑制作用

研究了Nostoc sp.FACHB87、Nostoc paludosum FACHB89等10株念珠藻的甲醇提取物对酪氨酸酶的抑制作用。结果表明,随着提取物浓度的升高,对酪氨酸酶的抑制作用也增强。其中Nostoc sp.FACHB892的甲醇提取物对酪氨酸酶抑制作用最强,在33.3μg/mL的最高测试浓度下,抑制率可达到60.54%;Nostoc sp.FACHB95、Nostoc sp.FACHB106、N.punctiforme FACHB252、N.calcicola FACHB389和N.par