Blackening of canned prawn and its prevention

The paper gives an account of the types of blackening associated with canned prawn in brine and their control. It was found that blackening caused by iron sulphide could be controlled by maintaining proper titratable acidity of fill brine in cans. The paper also elaborates on the factors responsible for or governing this critical titratable acidity. In regard to copper sulphide blackening, control was found to be difficult by maintaining the acidity or by additives such as EDTA when the copper content in the material went above the critical level.

Performance of paddy-cum-prawn culture in rainfed low land ecosystem of Sunderbans

Performance of both paddy (Var. NC 492) and prawn Penaeus monodon were assessed for two years during wet-season in rainfed lowland ecosystem with a view to study the economic viability of paddy-cum-prawn culture in the coastal saline zone of West Bengal. Both mono and dual culture of paddy and prawn were tried in the study. Fingerlings of prawn (α 35,000 haˉ¹) of 10-15 mm size were reared for about three and half months with and without fish feed. It was observed that addition of fish feed resulted in higher (57.7%) production of prawn (2.65 mg/haˉ¹) but not rice. Such increase in prawn production was 1.6 times higher when no feed was provided and 1.4 times higher when grown as sole crop. However, paddy, whether grown as mono or mixed culture, did not differ in yield significantly. In dual culture, the benefit - cost ratio was higher (6.83) when prawn was grown with feed and it was maximum (36.0) when grown without feed as sole crop. The study, therefore, indicates that paddy-cum-prawn culture under low land ecosystem of the coastal saline zone is enterprising particularly for small and marginal farmers who fear to take risk of growing prawn alone at the cost of paddy.

Comparative account of growth rate of body parts with total length in Rita pavimentata (Gunther)

The paper deals with sex-wise growth rate of different body parts in relation to total length in Rita paviinentata (Gunther). Growth rates calculated on pooled data by using the common regression coefficient 'b' reveals isometric and homogeneous nature in sexes.

Solid particle erosion of boronized steels

Boronizing is a thermochemical diffusion-based process for producing iron boride layers in the surface of steel components. The boride layer is wear resistant and is very hard. Large residual stresses are found to exist in the surface layers, which are a function of substrate steel composition and heat treatment. By slow cooling from the boronizing temperature (900°C), a large compressive stress is developed in the boride layer. Hardening the steel by rapid cooling, either directly from the boronizing treatment or after subsequent austenitizing, develops tension in the coating which causes it to fracture. Tempering of the martensite produces compression in the coating, closing but not welding the cracks. The results of solid particle erosion experiments using silicon carbide, quartz, and glass bead erodents on boronized steels are presented.

Ultrafast all-optical wavelength conversion using an integrated amplifier/DFB laser

Wavelength conversion in the 1550 nm regime was achieved in an integrated semiconductor optical amplifier (SOA)/DFB laser by modulating the output power of the laser with a light beam of a different wavelength externally injected into the SOA section. A 12 dB output extinction ratio was obtained for an average coupled input power of 75 μW with the laser section driven at 65 mA and the amplifier section at 180 mA. The response time achieved was as low as 13 ps with the laser biased at 175 mA even with low extinction ratios. The laser exhibits a similar recovery time allowing potentially very high bit-rate operation.

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the University of Ceylon Vidyalankara Campus, Kelaniya. Pt. 13. Some remarkable ripicol insects of the Ceylonese fauna

New Ceylonese records namely, Euscelimena gavialis (Sauss.), Paranemobius pictus Sauss. and semiaquatic cockroaches of the genus Rhabdoblatta were found in the collection of Saltatorid and Dictyopterid insects.

Some key concepts in fisheries research and management, with emphasis on Mozambique

Some basic concepts of fishery economics and management, and fish population dynamics are recalled, as presented during a course held at the Instituto de Investigaçāo Pesqueira from 23 February to 15 March 1988 in Maputo, Mozambique. Also, some basic elements of length-based stock assessment are reviewed, with emphasis on their implementation through the “Compleat Elefan" package, used extensively during this course, when the participants analyzed their data and wrote first draft of manuscripts incorporating the results of these analyses. Some problems relative to sampling and to seasonal growth oscillations are discussed with special reference to conditions in Mozambique.

The prediction of hot streak migration in a high-pressure turbine

Accurate predictions of combustor hot streak migration enable the turbine designer to identify high-temperature regions that can limit component life. It is therefore important that these predictions are achieved within the short time scales of a design process. This article compares temperature measurements of a circular hot streak through a turning duct and a research turbine with predictions using a three-dimensional Reynolds-averaged Navier-Stokes solver. It was found that the mixing length turbulence model did not predict the hot streak dissipation accurately. However, implementation of a very simple model of the free stream turbulence (FST) significantly improved the exit temperature predictions on both the duct and research turbine. One advantage of the simple FST model described over more complex alternatives is that no additional equations are solved. This makes the method attractive for design purposes, as it is not associated with any increase in computational time.

眼镜王蛇泛素融合蛋白基因和核糖体蛋白L30 基因的克隆及分析

从广西产眼镜王蛇( Ophiophagus hannah) 毒腺中抽提总RNA , 经mRNA 纯化后构建眼镜王蛇毒腺 cDNA 文库。从所构建的cDNA 文库中, 随机筛选200 个克隆测序, 得到两个在进化上高度保守的基因: 泛素融 合蛋白基因(GenBank 登录号为AF297036) 和核糖体蛋白L30 基因(GenBank 登录号是AF297033) 。前者cDNA 的开放阅读框为387 bp , 后者为348 bp 。前者编码128 个氨基酸残基组成的泛素融合蛋白前体; 后者编码115 个氨基酸残基组成的核糖体蛋白L30 前体。由cDNA 序列推导出的氨基酸序列分析表明, 泛素融合蛋白前体包 括N - 末端的泛素结构域(76 个氨基酸残基) 和C - 末端的核糖体蛋白L40 结构域(52 个氨基酸残基) 。该蛋 白为一高碱性蛋白, C 末端含有一个“锌指”模式结构。与16 个物种比较的结果表明, 眼镜王蛇与脊椎动物的 泛素融合蛋白氨基酸序列相似度较高, 具有高度的保守性。

Effect of feed quality restriction followed by realimentation on growth, nutrient utilization, biochemical changes and haematological profiles of Indian major carp, rohu (Labeo rohita H.)

To investigate the effect of protein restriction with subsequent re-alimentation on nutrient utilization, hematological and biochemical changes of Indian major carp, Rohu (Labeo rohita H.), 150 acclimatized Rohu fingerlings (average 20.74 ± 0.13 g) divided into five experimental groups (30 fingerlings in each groups with three replications with 10 fingerlings in each) for experimental trial of 90 days using completely randomized design. Control group (T sub(CPR)) was fed with feed having 30% crude protein at 3% of body weight for 90 days trial period. Other experimental groups T sub(1PR) was alternatively 3 days fed with feed having 20% CP and 30% CP at 3% of body weight, T sub(2PR) was alternatively 7 days fed with feed having 20% CP and 30% CP at 3% of body weight, T sub(3PR) was alternatively 15 days fed with feed having 20% CP and 30% CP at 3% of body weight and T sub(4PR) was alternatively 25 days fed with feed having 20% CP and 30% CP at 3% of body weight during 90 days trial period with daily ration in two equal halves at morning and afternoon. It was noticed that retention of different nutrients was almost similar among all treatment groups indicated improvement of digestibility of nutrients might not be the mechanisms for recovery growth in carps. Increased percent feed intake of body weight (hyperphagia) (4.14 ± 0.30 or 4.94 ± 0.46 and 3.33 ± 0.29), improved specific growth rate (1.86 ± 0.09 or 2.26 ± 0.05 and 1.43 ± 0.01), absolute growth rate (1.57 ± 0.08 or 1.84 ± 0.18 and 1.36 ± 0.12), protein efficiency ratio (1.19 ± 0.11 or1.16 ± 0.12 and 1.05 ± 0.09) were the important mechanism showing better performance index (21.60 ± 1.09 or 23.80 ± 0.21 and 19.45 ± 0.37) through which the experimental groups which were protein restricted and re-alimented at 3 or 7 days alternatively during 90 days trial period could able to compensate the growth retardation and to catch up the final body weight of control (128.68 ± 11.53 g/f) but other experimental groups failed to compensate during 90 days trial period. Result of the present study indicated that deprived fish i.e., fish received alternate 3 or 7 days protein restriction and re-alimentation showed recovery growth had still lower values of Hb (10.21 ± 0.02, and 9.88 ± 0.04 g/dl), hematocrit value (30.62 ± 0.05 and 26.64 ± 0.11%), total erythrocytic count (3.40 ± 0.01 and 3.29 ± 0.01 X10super(6) mm³), plasma glucose (126.93 ± 0.20 and 126.67 ± 0.05 mg/dl), total plasma lipid (1.04 ± 0.01 and 1.02 ± 0.01 g/dl) and liver glycogen (290.10 ± 0.80 and 288.99 ± 0.95 mg/kg) in comparison to control (10.56 ± 0.08 g/dl, 31.68 ± 0.24%, 3.52 ± 0.03 X10super(6) mm³, 128.23 ± 0.25 mg/dl, 1.07 ± 0.01g/dl and 292.00 ± 0.23 mg/kg) at the end of 90 days trial but total plasma protein in deprived group was compensated with advancement of trial period. All hematological and biochemical parameters studied were proportionately lowered in the experimental group got higher degree of deprivation. These findings suggested that with the increase of trial length complete compensation of hematological and biochemical profiles of rohu might be achieved. The results indicated that the implementation of alternative 7 days low and high protein diet feeding during aquaculture of carps could make economize the operation through minimizing the feed input cost.

Quality assessment of rotating and solar tunnel dried marine fish product

Studies were conducted to evaluate the quality aspects of marine dried fish i.e. silver jew fish (Johnius argentatus), Bombay duck (Harpodon nehereus) and ribbon fish (Trichiums haumela) products produced in rotating and solar tunnel dryers. On the basis of organoleptic characteristics such as colour, odour, texture, broken pieces, insect infestation and overall quality, four member panels of experts evaluated the quality of the dried products obtained from both rotating and solar tunnel dryers and all the products were found in acceptable quality. Reconstitutions properties of samples were in the range of 51.05 to 98.75% for the dried fish produced in rotating dryer, while 24.64 to 76.76% for dried fish produced in solar tunnel dryer. The highest reconstitution rate was found in dried silver jew fish and lowest in ribbon fish produced in rotating dryer. On the other hand, the highest reconstitution was observed in dried silver jew fish and lowest in dried Bombay duck produced in solar tunnel dryer. Proximate composition such as moisture, crude protein, lipid and ash content of the dried fish muscles produced in rotating dryer ranged from 16.36% to 19.1%, 62.35% to 67.37%, 6.37% to 10.75% and 7.00% to 8.05%, respectively and in solar tunnel dried fish products, they were in the range of 14.05% to 19.71%,57.64% to 69. 21%,6.92% to 15.40%and 7.69% to 8.80 %, respectively. The TVBN values of dried fish products obtained from rotating dryer were in the range of 15.02 to 19.05 mg/100g, while in solar tunnel dried fish products, the values were in the range of 15.46 to 19.21 mg/100g. The results of the studies indicated that dried fish produced from both rotating and solar tunnel drier were acceptable quality in terms of organoleptic and food quality aspects.

Utilization of trash fish for human consumption. 3: Studies on the development of fish pickle from Nemipterus japonicus

A method for the preparation of fish pickles from a lean variety of fish namely pink perch (Nemipterus japonicus) is described. Dipping the fish in 10% sodium chloride solution containing 6% acetic acid before pickling, was found desirable for retaining the meaty texture of the product. The product has no fish smell or flavour and has a shelf life of more than six months at ambient temperatures and scored very well in organoleptic tests.