Selven,S; Dr.Rosamma,Philip(Cochin University of Science and Technology, May , 2008)
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Abstract:
Aquaculture has developed to become one of the fastest growing food producing sectors in the world.Today India is one among the major shrimp producing countries in the world.There are extensive and intensive shrimp culture practices. In
extensive shrimp culture, shrimps are stocked at low densities (< 25 PLs m'2)in large ponds or tidal enclosures in which little or no management is exercised or possible. Farmers depend almost entirely on natural conditions in extensive cultures. Intensive shrimp culture is carried out in
high densities (>200 PLs m'2). Much of the world shrimp production still comes from extensive culture.There is a growing demand for fish and marine products for human and animal consumption. This demand has led to rapid growth of
aquaculture, which some times has been accompanied by ecological impacts and economic loss due to diseases. The expansion of shrimp culture always accompanies local environmental degradation and
occurrence of diseases.Disease out breaks is recognised as a significant constraint to aquaculture production. Environmental factors, water quality, pollution due to effluent discharge and pathogenic invasion due to vertical
and horizontal transmission are the main causes of shrimp disease out breaks. Nutritional imbalance, toxicant and other pollutants also account for the onset of diseases.
pathogens include viruses, bacteria, fungi and parasites.Viruses are the most economically significant pathogens of the cultured shrimps world wide. Disease control in shrimp aquaculture should focus first on preventive measures for eliminating disease promoting factors.ln order to design prophylactic and proactive measures against shrimp diseases, it is mandatory to understand the immune make up of the cultivable species,
its optimum culture conditions and the physico chemical parameters of the rearing environment. It has been proven beyond doubt that disease is an end result of complex interaction of environment, pathogen and the host animal. The aquatic environment is abounded with infectious microbes.The transmission of disease in this environment is extremely easy,
especially under dense, culture conditions. Therefore, a better understanding of the immune responses of the cultured animal in relation to its environmental alterations and microbial invasions is essential indevising strategic measures against aquaculture loss due to diseases. This study accentuate the importance of
proper and regular health monitoring in shrimps employing the most appropriate haematological biomarkers for application of suitable prophylactic measures in order to avoid serious health hazards in shrimp culture systems.
Suresh, K; Dr.Mohandas, A(Cochin University of Science And Technology, January , 1988)
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Abstract:
It is well known that under certain conditions, populations of oysters
and clams are susceptible to destructive epizootics caused by pathogenic
micro-organisms. It has also been shown that exposure of mammals to certain
heavy metals causes increased susceptibility to and severity of microbial
infections (Koller, 1980). Consequently, pollutants that affect haemocyte
viability or interfere with internal defence functions of the haemocytes which
are considered as the major means of defence in moliuscs against invading
foreign organisms and pathogens (Cheng, 1981) may have profound effect on
long term survival of molluscan populations. All these justify the significance
of the present study in the context of the current status on molluscan
culture programme, and how the data on molluscan haematological studies
.could be taken as the reliable criteria for pollution monitoring studies.
Description:
School of Marine Sciences, Cochin University of Science and Technology
Neil, Scholastin Correya; Dr.Rosamma,Philip(Cochin University of Science And Technology, October , 2012)
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Abstract:
The marine environment is indubitably the largest contiguous habitat on
Earth. Because of its vast volume and area, the influence of the world ocean on
global climate is profound and plays an important role in human welfare and
destiny. The marine environment encompasses several habitats, from the sea
surface layer down through the bulk water column, which extends >10,000 meters
depth, and further down to the habitats on and under the sea floor. Compared to
surface habitats, which have relatively high kinetic energy, deep-ocean circulation
is very sluggish. By comparison, life in the deep sea is characterized by a relatively
constant physical and chemical environment. Deep water occupying the world
ocean basin is a potential natural resource based on its properties such as low
temperature, high pressure and relatively unexplored properties. So, a judicious
assessment of the marine resources and its management are essential to ensure
sustainable development of the country’s ocean resources.
Marine sediments are complex environments that are affected by both
physiological and biological factors, water movements and burrowing animals.
They encompass a large extent of aggregates falling from the surface waters. In
aquatic ecosystems, the flux of organic matter to the bottom sediments depend on
primary productivity at the ocean surface and water depth. Over 50% of the earth’s
surface is covered by deep-sea sediments that are primarily formed through the
continual deposition of particles from the productive pelagic waters (Vetriani et al.,
1999). These aggregates are regarded as ‘hot spots’ of microbial activity in the
ocean (Simon et al., 2002). This represents a good nutritional substrate for
heterotrophic bacteria and favours bacterial growth
Description:
School of Marine Sciences, Cochin University of Science And Technology
Santhi, Thirumani S; Dr.Chandrika, V(Cochin University of Science And Technology, June , 1992)
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Abstract:
The principal interest of the present investigation was to determine
seasonal and vertical variation of chemoorganotrophic utilisation of glucose
and sodium—acetate by the natural bacterial population in the aquaculture
pond of Narakkal, Cochin using techniques which allow maintenance of
the in situ gaseous concentrations during incubation. In addition salinity,
dissolved oxygen, temperature, hydrogen—ion—.concentration, primary production,
plant pigments and total bacterial concentration were determined
seasonally and vertically because of their possible relationship to chemoorganotrophy.
Hamsakutty, V; Dr.Mathew, K T(Cochin University of Science and Technology, March , 2007)
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Abstract:
In this thesis, the author proposes a new geometry DR antenna-the Hexagonal Dielectric Resonator Antenna(HDRA)-capable of multiple frequency operation on a single feed of excitation.This avoids the conventional use of miniaturizes the structure.The properties of the HDRA on microstrip as well as coaxial feeding have been studied.The analysis of radiation characteristics indicates a gain comparable with other shapes.The antenna is capable of providing efficiency around 98%.The simulation using HFSS also yields results in conformity with the experimental results.Mode analysis is carried out and the modes are identified.The determination of the reflection characteristics through theoretical analysis using FDTD validates the multifrequency operation of the antenna,The antenna finds application in DCT,PCS and WLAN bands.
Description:
Department of
Electronics, Cochin University of Science and Technology
Vimalkumar, T V; Dr.Vijayakumar, K P(Cochin University of Science & Technology, August , 2011)
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Abstract:
In the present work we report the preparation details studies on ZnO thin films. ZnO
thin films are prepared using cost effective deposition technique viz., Chemical Spray
Pyrolysis (CSP). The method is very effective for large area preparation of the ZnO thin
film. A new post-deposition process could also be developed to avoid the adsorption of
oxygen that usually occurs after the spraying process i.e., while cooling. Studies were done
by changing the various deposition parameters for optimizing the properties of ZnO thin
film. Moreover, different methods of doping using various elements are also tried to
enhance the conductivity and transparency of the film to make these suitable for various
optoelectronic applications.
Description:
Department of Physics,
Cochin University of Science and Technology