Some changes in the physical qualities of muscle lipid of the freshwater murrel, Ophicephalus striatus (bloch.) during storage

The present communication reports the changes in the specific gravity, coefficient of viscosity, fluidity and surface tension of the muscle lipid of O. striatus, a common freshwater murrel, when stored at room temp (32 ± 2°C) The specific gravity of muscle lipid was found to rise from 0.894 to 0.912 during the first 25 days of storage but registered the highest (0.925) when stored for 50 days. Surface tension seemed to rise with the duration of storage. This was, presumably, due to an increase in the forces with which the molecules in the surface of the lipid tended to compress the molecules below to the smallest possible volume. During the period of storage marked changes seemed to occur in the direction of an increase in the value of the coefficient of viscosity and a reciprocal decline in the fluidity. Evidently, the observed increase in the viscosity seemed to be the result of increased internal friction between different molecular layers of the lipid, whereas a decline in the fluidity was perhaps the consequence of its inverse correlation with the coefficient of viscosity.

A brief account on the 'Gunja Net' fishing of the Kutch Backwaters (Gujarat)

A survey was made of the fishing gear (Gunja net) and methods used in the prawn fishery of the coastal waters of the Gulf of Kutch.

生物系统中的对称性

该文是在讨论生物系统中的非线性问题(刘次全等, 1992)的基础上, 进而讨论生物系统的对称性问题. 重点分析了生物系统在分子层次的对称性以及在生命进化和发展中对称性逐步破缺的过程。

Effect of demonstration in transferring fish processing technology

A group of 28 fisherwomen who attended demonstration on three subjects, namely, preparation of fish wafers, fish pickles and fish soup powder showed significant knowledge and skill gain for all the three messages. The total knowledge and skill gain was maximum for preparation of fish wafers followed by that for preparation of fish soup powder and fish pickles.

Status and prospects of mackerel and tuna fishery in Bangladesh

Present status and future prospects of mackerel and tuna fisheries in Bangladesh were assessed during July 2003-June 2004. The work concentrated on the fishing gears, length of fishes, total landings and market price of the catch and highlighted the prospects of the fishery in Bangladesh. Four commercially important species of mackerels and tuna viz. Scomberomorus guttatus, Scomberomorus commerson, Rastrelliger kanagurta, and Euthynnus affinis were included in the study. About 95% of mackerels and tuna were caught by drift gill nets and the rest were caught by long lines (4%) and marine set-bag-net (1%). Average monthly total landing of mackerels and tunas was about 264 t, of which 147 t landed in Cox's Bazar and 117 t in Chittagong sites. Total catches of the four species in Cox's Bazar and Chittagong sites were found to be 956 and 762 t, respectively. The poor landing was observed during January-February and the peak landing was in November and July. Gross market value of the annual landing of mackerels and tunas (1,718 t) was found to be 1,392 latch taka. Nevertheless, the mackerel and tuna fisheries in Bangladesh are increasingly contributing to the marine fish production of the country and have very good potential for further expansion for both domestic and export market.

Study on fish hatchery and nurseries in Mymensingh, Bangladesh

In generally, fish hatchery and nursery owners having both hatchery and nursery facilities were financially stronger, well-educated and well-trained than only nursery ponds owners in Mymensingh aquaculture region. On the other hand, only nursery pond owners were more experienced in fish seed business than only hatchery owners. Most of the owners were satisfied with existing communication facilities. Lack of technical knowledge was one of the major constraints which could be solved by ensuring proper training. This business can be made more profitable providing loan to poor farmers and improving law and order situation.

Coupling between elytra of some beetles: Mechanism, forces and effect of surface texture

Lightweight materials, structures and coupling mechanisms are very important for realizing advanced flight vehicles. Here, we obtained the geometric structures and morphologies of the elytra of beetles and ascertained its coupling zone by using the histological section technique and SEM. We set up a three-dimensional motion observing system to monitor the opening and closing behaviour of elytra in beetles and to determine the motion mechanism. We constructed a force measuring system to measure the coupling forces between elytra. The results show that elytra open and close by rotating about a single axle, where the coupling forces may be as high as 160 times its own bodyweight, the elytra coupling with the tenon and mortise mechanism, surface texture and opening angle between elytra heavily influence the coupling forces. These results may provide insights into the design mechanism and structure for future vehicles of flight.

Assessment of the heavy metals among suspended particulates and dissolved phases in Suez Canal water

The concentrations and distribution of particulate and dissolved heavy metals, viz: Cu, Zn, Pb, Cd, Fe and Mn have been determined seasonally during 2003 in water samples collected from the Suez Canal. The presented data clarifies that the metals exhibited clear differences in their distribution between particulate and dissolved forms. The concentration of particulate heavy metals ranged between 0.09-3.13, 0.57-15.02, 0.18-3.87, 0.02-0.73, 2.74-49.62 and 0.15-5.08 µg/L for Cu, Zn, Pb, Cd, Fe and Mn, respectively. In the same respect, these values for dissolved forms were 0.28-4.12, 0.57-9.08, 0.27-2.50, 0.02-1.24, 1.94-42.50 and 0.11-3.65 µg/L. The concentrations of particulate metals viz: Zn, Pb, Cd, Fe and Mn were high was compared to the dissolved forms. Dissolved copper, rather than particulate, showed the highest percentage of total copper. The particulate forms of Pb, Cd, Fe and Mn always had higher concentrations than the dissolved forms during the course of study except in the summer season. The northern part of the Suez Canal at Port Said showed mean concentrations of particulate and dissolved Cu=1.43 and 2.10, Zn=8.61 and 3.17, Pb=1.72 and 1.23, Cd=0.35 and 0.35, Fe= 23.49 and 15.83 and Mn=2.09 and 1.82 µg/L. These high concentrations may be attributed to the greater activities, particularly loading and unloading operations at Port Said harbour s industrial effluents and domestic drainage of Port Said city. In contrast, the Sinai side could be considered as reference site, as it was almost clean, i.e., without harmful outfalls, where Cu=0.16 and 0.56, Zn=2.14 and 0.94, Pb=6.29 and 3.44, Cd=0.055 and 0.088, Fe=6.29 and 3.44 and Mn=0.56 and 0.26 µg/L for particulate and dissolved metals respectively.

不同藏獒群体血液蛋白遗传变异与聚类分析

为了分析不同群体藏獒血液蛋白基因座的遗传变异及藏獒与其他犬种的亲缘关系,试验采用聚丙烯酰胺凝胶电泳技术,以青海藏狮犬和青海土种犬为对照,对2个藏獒群体的9个血液蛋白基因座的遗传变异进行了检测。结果表明:河曲藏獒群体内遗传变异较青海藏獒丰富,而两个藏獒群体间的遗传分化程度很低(GST=0.0187);青海藏獒与青海藏狮犬、青海土种犬的遗传关系近于河曲藏獒,并且4个青藏高原犬群在聚类图上形成一个独立的分支,与其他犬种之间遗传关系较远。