Effect of delayed icing on the quality of tiger shrimp (Penaeus monodon Fab.)

Effect of delayed icing on the quality of Penaeus monodon iced after three hours of harvest was studied in plastic and bamboo baskets. After harvest of three hours at ambient temperature (28°-32°C), ice was added to the shrimp at a ratio of 1:1 (shrimp:ice) and stored for 21 hours in both the baskets. Quality evaluation was carried out through visual assessment, biochemical analysis and microbial analysis for 24 hours. The organoleptic evaluation and scoring was done from the time of harvest treated as 0 hour and the average score was 10. At 9th hour after iced condition quality of shrimp was found reduced to the next stage (acceptable) with a score ranged from 8.4-6.5 in both baskets. This acceptable stage was observed throughout the experiment for bamboo basket whereas in the plastic basket the quality was reduced to a small extent with a score of 6.4 (moderately acceptable). Till the end point of the experiment the quality of shrimp was acceptable in respect to biochemical analysis. The microbial load was found log sub(10) 3.99±0.12 cfu/g to log sub(10) 4.33±0.21 cfu/g and log sub(10) 4.01 ±0.12 cfu/g to log sub(10) 4.83±0.19 cfu/g in the bamboo and plastic basket respectively. The importers or buyers suggests for immediate icing to maintain good quality but results of the present experiment suggest that the quality does not vary drastically for first three hours.

Species diversification in coastal aquaculture: production potentials of shrimp (Penaeus monodon) with mono and mixed sex tilapia

An experiment of 120 days of culture was conducted in brackishwater earthen ponds having an area of 0.2ha each. The hatchery produced shrimp (Penaeus monodon) post larvae were stocked in the 40m² fine meshed nylon net nursery enclosures were fed with commercial pellet feed. After two weeks of nursing, juveniles were allowed to spread in cultural pond by opening the fence. Fingerlings of three different strain of tilapia were stocked as shrimp and Strain-1 all male (monosex) (T1), shrimp and Strain-2 all male (T2), shrimp and Strain-3 mixed sex population (T3) @ 20.000/ha and 10.000/ha, respectively and shrimp only (monoculture) (T4) @ 20.000/ha. The shrimp and fish were fed with farm made feed consisting of a mixture of fishmeal 29%, MOC 15%, rice bran 30%, soybean meal 16%, wheat flour 9% and vitamin premix 0.1%. The average final weight of shrimp was 24.9±1.13g, 23.41±3.26g and 26.67±1.89g that stocked with tilapia in treatments T1, T2, and T3 respectively. The final average weight of shrimp in monoculture (T4) was 27.41±0.76g, apparently higher but insignificant in treatments. The survival of shrimp was 42.17%, 32.38%, 39.45% and 61.98% in treatments T1 T2, T3 and T4 respectively. The production of shrimp in concurrent culture was 193.67, 154.26 and 210.41kg/ha in T1, T2 and T3, respectively, while in monoculture (T4) was 339.77 kg/ha. The growth and survival of tilapia among the treatments was insignificant. The growth of monosex tilapia ranged 225.29 and 291.31g and survival 62.77 and 72.20% in T1 and T2, respectively, in mixed sex was 193.0g and 83.20% (T3). The production of tilapia monosex strains was 1676.69kg/ha (Strain-2 all male) and 1668.98 kg/ha (Strain-1 all male) while that of Strain-3 mixed sex population was 1622.92 kg/ha.

A new species of bamboo bat (Chiroptera : Vespertilionidae : Tylonycteris) from southwestern China

Bamboo bats are a group of small bats with unique skull and morphology. They roost inside hollow bamboo stems in tropical and subtropical Asia and the Ambon Islands (Moluccas). We examined 53 specimens of Tylonycteris from southern and southwestern China. Comparisons of skull and external characteristics, pelage color, shapes of thumbpads and footpads, and statistical analysis of cranial measurements revealed that specimens from Damenglong, Jinghong County, Xishuang-banna, Yunnan, are distinctly different from the other two species of Tylonycteris described so far. The Yunnan specimens are the smallest in size; have dark blackish brown pelage color; and have larger upper premolars, smaller first lower premolars, and longer C-M-3. They are sympatric with the previously described species. Here we review the genus Tylonycteri and describe a new species, Tylonycteris pygmaeus, from the Yunnan material.

Hybridization between Tilapia zillii (Gervais) and Tilapia andersonii (Casteinau) at the Freshwater Fisheries Institute, at Nyegezi, Tanzania

As a part of an overall project on fishculture development techniques in Tanzania, hybridization between Tilapia zillii and Tilapia andersonii was carried out at the Freshwater Fisheries Institute, Nyegezi, Tanzania. T. andersonii, a plankton feeder, is not indigenous to Tanzania but was introduced in 1968 from Zambia for certain specific purpose. T. zillii, a macrovegetation feeder, is present locally and is common. In the present studies T. zillii (245.0 mm/260.0 g) female was hybridized with T. andersonii (288.0 mm/350.0 g) male. Under cement cistern conditions it was only after about four months of acclimatization that hybridization between the two occurred. About 1,637 interspecific hybrid fry were produced in a single brood. Eggs were adhesive and parental care shown by the female, the male being driven away. Growth under cistern conditions was slow, attaining a size of 134.8 mm/44.3 g in 10 months. But this growth rate need not be taken as ideal. In body shape, colouration and other morphometric characters the hybrids had inherited from both parents. The number of gill rakers among the hybrids was eighteen which was intermediate between T. zillii (12) and T. andersonii (27). Among one hundred and seventy two specimens (106.0 mm - 168.0 mm) cut and examined the sex ration was hundred per cent males and all of them were between II and IV stages of maturity. This is the first report of fish hybridization from Tanzania and possibly the first report on hybridization between T. zillii and T. andersonii. The full significanoe of the findings and its role in African fishculture is discussed.

Group Size and Composition of Black．and．White Snub．nosedMonkey(rhinopithecus)Estimated by Faecesof Sleeping Sites at Baima Snow Mountain

介绍了应用过夜地粪便来估计白马雪山黑白仰鼻猴群大小和组成的一种方法。该物种以单雄多雌单 元和全雄组的形式在树上过夜。粪粒根据其大小可分为3种类型：成年雄性的(最大)、成年雌性的(中等大小)和 未成年个体的(最小)。2000一2001年，搜集了滇西北白马雪山国家级自然保护区北部南任村(99。04 7E，28。34 7N) 附近黑白仰鼻猴群每个季节2个过夜地的粪粒。根据2001年11月猴群通过开阔地的数据来确定猴群组成。每个 季节，由于单雄多雌单元的成年个体数与其粪粒数正相关，所以二者回归直线的斜率可以看作是每个个体每晚 的平均排便量。由于该物种的栖息地主要为高山峡谷，而且能见度较低，因此，利用过夜地粪便比以前通过猴群 活动痕迹来估计猴群大小和组成相对准确、可靠。从估计成年雌性个体数的角度看，利用粪粒来估计种群大约有 9．4％的偏差。导致偏差的可能原因有杂草和灌丛对粪粒准确计数的影响、个体排粪率的差异以及成年雄性最小 粪粒与成年雌性最大粪粒的混淆等。该方法适应于栖息地和主要食物与本文研究种群相似的其他种群。

XMolecular Cloning and Sequence Analyses of cDNAs Encoding Seven C2type Lectin2like Protein Subunits from Daboia russellii siamensis

按照Promega 公司的mRNA 提取试剂盒操作手册, 从圆斑蝰蛇( Daboia russellii siamensis ) 的毒腺中提 取mRNA ; 利用RT2PCR 的方法进行体外扩增, 获得C - 型凝集素蛋白的基因, 克隆到pMD182T 载体中。随机挑 选14 个阳性克隆进行核酸测序, 获得7 个编码不同蛇毒C - 型凝集素样蛋白亚基的cDNA , 分别命名为DRS2L1 、 DRS2L2 、DRS2L3 、DRS2L4 、DRS2L5 、DRS2L6 和DRS2L7 。由基因序列推导出的氨基酸序列表明, 克隆到的7 个蛇 毒C - 型凝集素样蛋白的亚基中均有糖识别结构域存在。BLAST 分析显示, 仅有DRS2L1 的蛋白序列与目前已知 的蛇毒C - 型凝集素样蛋白的α亚基相似。序列同源性比较并结合半胱氨酸位点分析, 推测DRS2L1 和DRS2L2 可能分别是圆斑蝰蛇毒Ⅹ因子激活剂的轻链LC2 和LC1 。DRS2L3 和DRS2L4 可能是高分子量的蛇毒C - 型凝集 素样蛋白的β亚基, 而DRS2L5 和DRS2L6 可能是低分子量的蛇毒C - 型凝集素样蛋白的β亚基。DRS2L7 可能是 类似于血小板膜糖蛋白Ib 结合蛋白的β亚基。

Operating charts for the brushless doubly-fed machine (BDFM)

The Brushless Doubly-Fed Machine (BDFM) is an electrical machine that allows brushless operation in many applications where the Doubly-Fed Induction Generator (DFIG) is currently used. In recent years work on BDFM control means that the machine can now be run stably across its working range. However, little work has been done to define the working area in which BDFM can safely be operated without exceeding its material and stability limits. This paper sets out the theoretical backing for an operating chart of an ideal BDFM similar to that of the synchronous machine. It goes on to show that though the ideal chart gives the right form, non-ideal parameters (especially the finite magnetizing inductances) significantly effect the locations of the limits. Some preliminary experimental data obtained for a 225 frame size machine support the form of the chart. Finally it is shown how the operating chart can be used to chose appropriately sized converters for the BDFM. © 2009 IEEE.