Estimates of growth, mortality, recruitment pattern and MSY of important resources from the Maharashtra coast

Based on the data collected from the year 1987-1991 the growth, mortality and recruitment pattern of eighteen species of fish, two species of cephalopods and four species of penaeid prawns have been presented in the present communication. The total mortality coefficient, (Z) varied from lowest of 1.20 for O. cuvieri to a highest of 10.78 for P. stylifera. The natural mortality coefficient, (M) varied from 0.52 for T. thalassinus to 3.44 for S. crassicornis. The average annual yield of eighteen species of fish, four species of prawns and two species of cephalopods are 65.083, 38.404 and 11.373 tons as against the MSY of 83.023, 72.460 and 10.475 tons respectively. The MSY estimated for the total fish stock is 1.77.753 tons whereas the present yield is 1.14.859 tons. This indicates that higher yield can be obtained by increasing the effort.

Pattern of cutaneous wound healing in a live fish Clarias batrachus (L.)(Clariidae, Pisces.)

Incisional wounds of the same length and depth were made on skin between dorsal fin and the lateral line canal of Clarias batrachus and the pattern of wound closure has been studied histologically. Following infliction, a marked change in the colour of the skin surrounding the wound was observed which lasted for about 30 h and restored thereafter. Mucus and blood cells plugged the wound gap shortly after infliction. The epidermis surrounding the wound was found to be detached from the basement membrane. Mass movement of epidermal cells was observed from both side of the wound gap. The epidermal cells at the margin of the wound became hypertrophied. The epidermis became normal by 32 days. The dealing of sub-epidermal tissue indicated degenerative and regenerative changes of muscle fibres. The mucus and blood cells were accumulated in the wound gap and later fine blood vessels were formed. Gradually granulation tissue was formed and fibroblasts and myoblasts appeared. Myoblast differentiated into muscle bundles. The epidermal repair was completed within 35 days.

Optimal H2 order-one reduction by solving eigenproblems for polynomial equations

A method is given for solving an optimal H2 approximation problem for SISO linear time-invariant stable systems. The method, based on constructive algebra, guarantees that the global optimum is found; it does not involve any gradient-based search, and hence avoids the usual problems of local minima. We examine mostly the case when the model order is reduced by one, and when the original system has distinct poles. This case exhibits special structure which allows us to provide a complete solution. The problem is converted into linear algebra by exhibiting a finite-dimensional basis for a certain space, and can then be solved by eigenvalue calculations, following the methods developed by Stetter and Moeller. The use of Buchberger's algorithm is avoided by writing the first-order optimality conditions in a special form, from which a Groebner basis is immediately available. Compared with our previous work the method presented here has much smaller time and memory requirements, and can therefore be applied to systems of significantly higher McMillan degree. In addition, some hypotheses which were required in the previous work have been removed. Some examples are included.

New evidences on the distribution of predatory pelagic sharks in the tuna grounds of the Indian Ocean

Since the commencement of the exploitation of oceanic tuna resources of the Indian Ocean seventeen years ago, the hooked rates for the tuna species have declined in many areas of the Ocean but there are no evidences of such a trend in the case of the sharks. As a result, the percentage composition of sharks in the longline catches and the percentage of the tuna catch damaged by sharks show an increase. Hence there is an urgent need for innovation of the existing longline gear in order to increase the fishing efficiency for hooking the tuna species with a corresponding reduction in its efficiency for hooking sharks. At the beginning of this fishery, hooked sharks were discarded at sea, at a later stage the liver and fins were taken and the carcass discarded and presently the sharks are also brought along with the tuna catch. Though the shark meat has a very low market value it is brought in order to cover up for the declining tuna catches. Thus it has become very necessary to increase the demand for shark meat by developing products or by-products utilizing shark meat and ensuring the successful continuity of the tuna longline fishery. The pattern of distribution of shark species in the time grounds of the Pacific, Indian and Atlantic Oceans and also the predation of hooked tunas by sharks were discussed earlier (Sivasubranianiam 1963, 1964 and 1966). Some contribution to these studies is made in this paper based on new data become available.

Defect and disorder reduction by annealing in hydrogenated tetrahedral amorphous carbon

Hydrogenated tetrahedral amorphous carbon (ta-C:H) is a form of diamond-like carbon with a high sp3 content (>60%), grown here using a plasma beam source. Information on the behaviour of hydrogen upon annealing is obtained from effusion measurements, which show that hydrogen does not effuse significantly at temperatures less than 500 °C in films grown using methane and 700 °C in films grown using acetylene. Raman measurements show no significant structural changes at temperatures up to 300 °C. At higher temperatures, corresponding to the onset of effusion, the Raman spectra show a clustering of the sp2 phase. The density of states of ta-C:H is directly measured using scanning tunnelling spectroscopy. The measured gradients of the conduction and valence band tails increase up to 300 °C, confirming the occurrence of band tail sharpening. Examination of the photoluminescence background in the Raman spectra shows an increase in photoluminescence intensity with decreasing defect density, providing evidence that paramagnetic defects are the dominant non-radiative recombination centres in ta-C:H.

Reduction of porosity in RE1Ba2Cu3Oy pseudo crystals

The distribution of porosity in Y1Ba2Cu3Oy (Y-123) pseudo-crystals prepared by hot seeded melt growth of precursor pellet samples pre-sintered at elevated temperatures in air or vacuum has been investigated. The results demonstrate that the porosity within the Y-123 pseudo-crystal matrix could be reduced dramatically by pre-sintering in vacuum, compared with that for precursor pellets processed in air.

Evaluation of wave drag reduction by flow control

An analytical expression is proposed to estimate the wave drag of an aerofoil equipped with shock control. The analysis extends the conventional approach for a single normal shock wave, based on the knowledge that all types of successful shock control on transonic aerofoils cause bifurcated λ-shock structures. The influence of surface curvature on the λ-shock structure has been taken into account. The extended method has been found to produce fairly good agreement with the results obtained by CFD methods while requiring negligible computational effort. This new formulation is expected to be beneficial in the industrial design process of transonic aerofoils and wings where a large number of computational simulations have to be performed.

A new alternative for reduction of secondary flows in low pressure turbines

This paper describes a new flow mechanism for the reduction of secondary flows in Low Pressure Turbines using the benefit of contoured endwalls. The extensive application of contoured endwalls in recent years has provided a deeper understanding of the physical phenomenon that governs the reduction of secondary flows. Based on this understanding, the endwall geometry of a linear cascade of solid-thin profiles typical of Low Pressure Turbines has been redesigned. Experimental data are presented for the validation of this new solution. Based on these data, a reduction of 72% in the SKEH and 20% in the mixed-out endwall losses can be obtained. CFD simulations are also presented to illustrate the effect of the new endwall on the secondary flows. Furthermore, an explanation of the flow mechanism that governs the reduction of the SKEH and the losses is given. Copyright © 2006 by ASME.

Evolution of the black muntjac (Muntiacus crinifrons) karyotype revealed by comparative chromosome painting

The black muntjac (Muntiacus crinifrons) has an unusual karyotype of 2n = 8 in females and 2n = 9 in males. We have studied the evolution of this karyotype by hybridising chromosome-specific paints derived from flow-sorted chromosomes of the Chinese muntjac (M. reevesi, 2n = 46) to chromosomes of the black muntjac. The hybridisation pattern allowed us to infer chromosomal homologies between these two species. Tandem and centromeric fusions, reciprocal translocations, and insertions are involved in the reduction of the diploid number from 2n = 46 to 2n = 8, 9. The painting patterns further show complex chromosomal rearrangements in the male black muntjac which involve more than half the karyotype, including both sex chromosomes. Since early meiosis is reported to be normal without any visible inversion loops of the synaptonemal complex, the observed chromosomal rearrangements would lead to heterosynapsis and, therefore, leave a large fraction of the male black muntjac karyotype balanced between the two sexes.

Household consumption pattern and buying behavior for fish in an area Mymensingh, Bangladesh

The study was conducted on 238 households in Bangladesh Agricultural University campus and its adjoining areas in Mymensingh. The household were divided into four groups based on their per capita income. Monthly expenditure on fish, income elasticity of demand and marginal propensity to consume were calculated. 'Weighted average' method was used to study the level of preference for fish by sex and age groups and frequency of its purchase. The per capita monthly expenditure on fish of overall households was found to be Tk. 178.83. The consumption increased considerably between and among the income groups rising from Tk. 63.95 in the lowest income group to Tk. 249.11 in the highest income group. Based on income elasticity the proportion of income spent on fish was found to be greater than the proportion of increase in income for lower middle and upper middle income groups. However, percent expenditure decreased from 8.15 in lowest to 5.49 in the highest income group. Female members between 20 and 40yrs had the highest preference for fish in general followed by male members of above 40 yrs. Children (0 to 8 yrs), on the other band, had the least preference for fish, Sing and Magur (Catfishes) were the most preferred fish species for each age and sex group. Rui, a carp, was the single most purchased fish while the introduced exotic fishes were the least bought. Freshness was found to be the most important factor followed by the appearance and taste perception that positively affected the fish purchase.

Consumption pattern and consumer preference for value-added fish and fish products in north zone of India

Present paper attempts to analyze consumption pattern and consumer preferences towards value-added fish and fish products in north zone of India. Results reveal that socio economic variables affect consumption of value-added fish and fish products. A total of 49 percent respondents were of middle age group (35 to 50 years). All were literates except 7% from the rural area. All were purchasing fish at least once in 15 days. A total of 90% respondents in rural, 11% in semi urban and 50% in urban area were unaware of value-added fish and fish products. About 10% of respondents had consumed it, out of which most were from urban area. Demand analysis by Cobb Douglas (CD) Demand function revealed that when price of fish, price of the substitutes, income of family and family size were used as independent variables, variation in demand of fish explained by CD Demand function was about 39% in urban area, 24% in semi urban area and 22% in rural area. From Garette ranking technique major problems in fish consumption found were irregular supply, lack of fresh fish, high price and presence of bones in fish. While lack of awareness, unavailability, no preference and unacceptable taste were major problems for consumption of value-added fish and fish products.

Studies on the age and growth of Labeo calbasu (Hamilton) with an exploitation pattern from the Ganga River system, Uttar Pradesh (India)

Samples were collected to study the age and growth of Labeo calbasu (Hamilton) from the river Ghaghra (Guptarghat centre, Faizabad). The scales of L. calbasu have been used for age and growth studies in present paper. Study of the marginal rings on the scales of L. calbasu indicates their annual nature. The fish attained growth in 1st 18.7 cm, 2nd 27.8 cm, 3rd 35.7 cm, 4th 41.8 cm, 5th 46.9 cm, 6th 54.9 cm and 7th 57.4 cm years of the life. The growth rate was observed 18.7, 9.1, 7.9, 6.7, 5.1, 8.0 and 2.5 cm for 1st to 7th age classes respectively. The age groups 1+ to 4+ constituted 91.17% of the total exploited population and 8.83% of remaining age groups (5+ to 7+). The maximum exploited population was observed in 2+ age group with 33.68%. Overall exploitation pattern was systematic and a good indicator for heavy recruitment.

Assessing the potential of yield improvements, through process scrap reduction, for energy and CO2 abatement in the steel and aluminium sectors

Targets to cut 2050 CO2 emissions in the steel and aluminium sectors by 50%, whilst demand is expected to double, cannot be met by energy efficiency measures alone, so options that reduce total demand for liquid metal production must also be considered. Such reductions could occur through reduced demand for final goods (for instance by life extension), reduced demand for material use in each product (for instance by lightweight design) or reduced demand for material to make existing products. The last option, improving the yield of manufacturing processes from liquid metal to final product, is attractive in being invisible to the final customer, but has had little attention to date. Accordingly this paper aims to provide an estimate of the potential to make existing products with less liquid metal production. Yield ratios have been measured for five case study products, through a series of detailed factory visits, along each supply chain. The results of these studies, presented on graphs of cumulative energy against yield, demonstrate how the embodied energy in final products may be up to 15 times greater than the energy required to make liquid metal, due to yield losses. A top-down evaluation of the global flows of steel and aluminium showed that 26% of liquid steel and 41% of liquid aluminium produced does not make it into final products, but is diverted as process scrap and recycled. Reducing scrap substitutes production by recycling and could reduce total energy use by 17% and 6% and total CO 2 emissions by 16% and 7% for the steel and aluminium industries respectively, using forming and fabrication energy values from the case studies. The abatement potential of process scrap elimination is similar in magnitude to worldwide implementation of best available standards of energy efficiency and demonstrates how decreasing the recycled content may sometimes result in emission reductions. Evidence from the case studies suggests that whilst most companies are aware of their own yield ratios, few, if any, are fully aware of cumulative losses along their whole supply chain. Addressing yield losses requires this awareness to motivate collaborative approaches to improvement. © 2011 Elsevier B.V. All rights reserved.

Distribution pattern of some biochemical constituents in muscle of the common cat fish, Heteropneustes fossilis (Bloch)

The quantitative distribution pattern of fat, moisture, protein and ash has been studied in the muscle of the various zones corresponding to the dorsal and ventral regions of the body of a common cat fish, H. fossilis (Bloch). The ventral part of the body showed more accumulation of fat and ash than the dorsal part, while this dorso-ventral gradation was not marked in the case of protein content. All the four constituents also showed an increase from the anterior to the posterior zones, both in the ventral as well as dorsal regions of the body. The distribution of moisture followed an almost opposite pattern, indicating an inverse relationship with fat and ash contents.