SEXUAL DIMORPHISM AND GONADAL DEVELOPMENT OF A RARE MURREL SPECIES CHANNA BLEHERI (BLEHER) IN ASSAM

The reproductive biology of a rare murrel species Channa bleheri (Bleher) commonly known as ‘rainbow snakehead’ was studied during 2010-2011 in the laboratory of Faculty of Fishery Science, WBUAFS, Kolkota, West Bengal. The study revealed that the sexual dimorphism in C. bleheri exists in the form of a prominent dark blotch in the dorsal fin of the male fish which becomes distinct with the advancement of the maturity stage. Round or oval vent in female and elongated genital in male is another distinctive characteristic for identification of sexes in this species particularly during the breeding season. The Gonado somatic index (GnSI) in male was found to ranges between 0.127- 0.161% while in female it ranges from 0.810 - 3.519%. The peak GnSI value of male was during April to June (0.159-0.161%) while in female the highest value of GnSI were recorded during April to July (2.938- 3.519%). The presence of only one batch of maturing/mature ova indicates that the species breeds only once in a year which is supported by GnSI values exhibiting a single annual peak in both male and female

Modeling of WEDM Parameters while Machining Mg-SiC Metal Matrix Composite

In this paper an attempt has been made to study the effects of the process parameters of wire cut electrical discharge machining (WEDM) on Magnesium-Silicon Carbide MMC with 5% SiC in particulate form. For the analysis, six factors, namely pulse on time, pulse off time, spark gap voltage, peak current, dielectric flushing pressure and servo feed have been taken and a Taguchi L16 orthogonal array for two levels was used. Response surface methodology was also used to develop second-order models for material removal rate (MRR) and surface roughness (SR). From the analysis of variances, it has been observed that pulse on time and pulse off time were the most significant parameters among all those observed in predicting the MRR and SR, respectively

Short and Long-Term Sensitivity of Lab-Scale Thermocline Based Thermal Storage to Flow Disturbances

Molten-salt thermocline-based systems are a low-cost option for single-tank thermal energy storage in concentrated solar power plants. Due to the high variability in solar energy availability, these energy storage devices are subject to transient heat loads during charging that can affect the storage efficiency. Numerical simulations were conducted to analyze the stability characteristics of a lab-scale thermocline tank subject to a flow disturbance during charging under different operating temperatures. The charging process was first simulated at a constant Reynolds number for three different Atwood numbers; a stably stratified fluid layer develops inside the storage tank in all cases. A flow disturbance was then introduced at the inlet of the stratified thermocline tank by inserting colder fluid for a short period of time. The disturbance interacts with the thermocline and causes oscillations and mixing. The thermocline oscillations are under-damped and lead to an increase in thermocline region thickness. The transient behavior of the thermocline and the decay rate in its oscillations were analyzed; the damping time depends on the Atwood number. The persistence of flow disturbance effects during long-term cyclical operation was also investigated. Several charge/discharge cycles were simulated at constant Reynolds number to obtain a time-periodic thermal response for each Atwood number. The characteristic flow disturbance was introduced at the inlet during a single charging process, and the thermocline region was observed during several subsequent charge/discharge cycles to assess the long-term temporal attenuation of the disturbance. The thermocline almost fully recovers to the time-periodic behavior after a single cycle

Betel nut and tobacco chewing; potential risk factors of cancer of oesophagus in Assam, India

Cancer of the oesophagus is the most commonly diagnosed cancer in males in Assam, in north-eastern India, and ranks second for females. The chewing of betel nut, with or without tobacco and prepared in various ways, is a common practice in the region and a case–control study has been designed to study the pattern of risk associated with different ways of preparing and chewing the nuts. 358 newly diagnosed male patients and 144 female have been interviewed together with 2 control subjects for each case chosen at random from among the attendants who accompanied patients to hospital. There were significant trends in risk ratios associated with the frequency of chewing each day, with the duration of chewing in years and with the age at which the habit was started that were apparent for both males and females and which remained significant after allowance was made for other known risk factors, notably tobacco smoking and alcohol consumption. The adjusted ratios, in comparison with non-chewers, were 13.3 M and 5.7 F for chewing more than 20 times a day, 10.6 M and 7.2 F for persons who had chewed for more than 20 years and 10.3 M and 5.3 F for those who had started before the age of 20. Among the different combinations of ingredients that were chewed the adjusted odds ratios were highest for those who had been using fermented betel nut with any form of tobacco (7.1 M and 3.6 F). The risk associated with tobacco smoking and alcohol consumption, which are high in some parts of the world, were less in Assam than those associated with the chewing of betel nut. © 2001 Cancer Research Campaign http://www.bjcancer.co

Decision making under incompleteness based on soft set theory

[EN]Decision making with complete and accurate information is ideal but infrequent. Unfortunately, in most cases the available infor- mation is vague, imprecise, uncertain or unknown. The theory of soft sets provides an appropriate framework for decision making that may be used to deal with uncertain decisions. The aim of this paper is to propose and analyze an effective algorithm for multiple attribute decision-making based on soft set theory in an incomplete information environment, when the distribution of incomplete data is unknown. This procedure provides an accurate solution through a combinatorial study of possible cases in the unknown data. Our theoretical development is complemented by practical examples that show the feasibility and implementability of this algorithm. Moreover, we review recent research on decision making from the standpoint of the theory of soft sets under incomplete information