Two Parallel Finite Queues with Simultaneous Services and Markovian Arrivals

In this paper, we consider a finite capacity single server queueing model with two buffers, A and B, of sizes K and N respectively. Messages arrive one at a time according to a Markovian arrival process. Messages that arrive at buffer A are of a different type from the messages that arrive at buffer B. Messages are processed according to the following rules: 1. When buffer A(B) has a message and buffer B(A) is empty, then one message from A(B) is processed by the server. 2. When both buffers, A and B, have messages, then two messages, one from A and one from B, are processed simultaneously by the server. The service times are assumed to be exponentially distributed with parameters that may depend on the type of service. This queueing model is studied as a Markov process with a large state space and efficient algorithmic procedures for computing various system performance measures are given. Some numerical examples are discussed

Training needs of traditional marine fishermen in Kerala

Training needs of 80 fishermen in 25 subject areas revealed a mean training need score of 23.0l; 95% wanted to get trained. The training needs were fairly strong in all subject areas, with the highest demand being for fishery engineering. Training need was also high for areas related to fishery technology. Most of the fishermen preferred to have the training at their own village, and in the months of June or July for an average period of 20.85 days. Education and income were positively related to intensity of training needs whereas age, number of family members, number of employed family members and experience in fishing were negatively correlated with it. These six variables explained 27 of the variance in training need intensity

Development of novel techniques to maintain Chlorella spp. stock culture in artificial seawater

Chlorella spp. are used as feed to culture almost all species of zooplankton. Besides they form the important feed in the finfish/shell fish culture systems. Culture media such as Miquel's medium and Convey medium are conventionally used to maintain the stock culture of Chlorella spp. For the outdoor mass culture, water is enriched with groundnut oilcake, urea and super phosphate

Capture of a live South African cape locust lobster at Vizhinjam

landing centre informed the capture of a new lobster hitherto unknown to them. Immediately it was brought to CMFRI Marine Aquarium and kept alive and was identified to be slipper lobster of Scyllarides and the species confirmed as Scyllarides elisabethae, the South African locust lobster

The Present status of our knowledge on the lesser sardines of Indian waters

The results of research carried out at Waltair, Mandapam. Tuticorin and Vizhinjam and another centres on the lesser sardines over the past up till 1978 are reviewed in detail. In the twentyyear period from 1958 to 1978 there was an increasing trend of production of these fishes along the different coasts of India, the average annual landings nearly doubling from 36,000 t in 1958-67 to 70,000 t in 1968-78. The bulk of the catches came from Tamil Nadu, including Pondicherry, (32.6%), Kerala (32.2%) and Andhra Pradesh (26.5%)- Fishing was mostly by the labour-intensive traditional methods in close-shore waters, better catches coming from 30-55 m depths. Shore seines, boat seines and gill nets were the principal gears employed in the fishery though gill nets were the most effective

Spatial fluctuations at vertices of epithelial layers: quantification of regulation by Rho pathway

In living matter, shape fluctuations induced by acto-myosin are usually studied in vitro via reconstituted gels, whose properties are controlled by changing the concentrations of actin, myosin and cross-linkers. Such an approach deliberately avoids to consider the complexity of biochemical signaling inherent to living systems. Acto-myosin activity inside living cells is mainly regulated by the Rho signaling pathway which is composed of multiple layers of coupled activators and inhibitors. We investigate how such a pathway controls the dynamics of confluent epithelial tissues by tracking the displacements of the junction points between cells. Using a phenomenological model to analyze the vertex fluctuations, we rationalize the effects of different Rho signaling targets on the emergent tissue activity by quantifying the effective diffusion coefficient, the persistence time and persistence length of the fluctuations. Our results reveal an unanticipated correlation between layers of activation/inhibition and spatial fluctuations within tissues. Overall, this work connects the regulation via biochemical signaling with mesoscopic spatial fluctuations, with potential application to the study of structural rearrangements in epithelial tissues.Comment: 8 pages, 3 figure

An assessment of the exploitation of the sardine stock off Vizhinjam, Southwest coast of India

The sardine resources at Vizhinjam have been assessed based on bi-weekly observations and the present level of exploitation has been studied using the surplus production model. The average annual sardine catch has been estimated at 272 tomes, constituted by seven, species, viz. Sardinella gibbosa (40.0%), S. longiceps (23.1%), S. sirm (20.7%). S. davi (9.8%), S. fimbriata (4.8%). S. sindensis (1.2%) and S. clupeoides (0.4%). Gill net, boat seine, shore seine and hooks and line were the main gears employed for the fishery with contributions of 62%. 34%, 3% and 1% respective1 y. The suitable model for the catch and effort data for sardine fishery at Vizhinjam during the period 1970-77 seems to be that of Fox (1970) using boat seine as the standard effort. The MSY (419 t) was higher than that of the average catch (272 t), but the effort to get the MSY was less (58000) when compared to the average standard effort (112000) during the period. The landing of the three important species of Sardines, viz; S, gibbosa, S. longiceps and S. sirm, were also assessed by using the Schaefer and Fox models separately with boat seine as the standard effort. This also showed a need for the reduction in the effort to get the MSY of individual species

Bottle-nose dolphin stranded at Kovalam in Kerala

On 5th September 1998, an Indian bottle-nose dolphin {Tursiops truncatus aduncus Ehrenberg. 1833) was washed ashore at Ashoka beach in Kovalam

Influence of seasonality and lunar periodicity on the maturity pattern of Pinctada fucata for nucleus implantation in pearl culture

In India, the Central Marine Fisheries Research Institute, succeeded In developing a viable technology for pearl culture using Pinctadajiicata in 1973 and since then research is continuing to improve the technology. Further, the successful development of hatchery technology for the production of pearl oyster spat during 1981 led to production of pearl oyster seed overcoming the problem of non-availability of seed from the wild for pearl culture industr

Stranding of a rare marine dolphin at Vizhinjam

On sighting a dolphin struggling for survival In the near shore area off Adimaithura (near Vizhinjam) on 31-08-1998, the fishermen encircled it with a shore seine. It was a rare marine Risso's dolphin, Grampus griseus (Cuvier, 1812), measuring 250 cm in length. In spite of the medical treatments given for the injuries, it survived in the Marine Aquarium at Vizhinjam for about 13 hrs only