716 research outputs found
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
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