Biology, population characteristics and fishery of the speckled shrimp Metapenaeus monoceros (Fabricius, 1798) along the Kerala coast

Crustaceans comprising numerous edible species of prawns, lobsters and crabs inhabiting different ecosystem form significant portion of the aquatic food resources of the world. Among the crustaceans, prawns are the most commercially exploited group and hold premier rank by virtue of their importance as an esteemed food of gourmet and on account of their high export value. Met-ape-naeus manoceras (Fabricius, 1798) which is known IS,Speckled shrimp’ (FAD name) and ‘Brown shrimp’ ( common nameused in the industry) is one of the commercially important marine penaeid prawns of India. During 1995, M. monaceros catch constituted 7.5 Z of the all India marine penaeid prawn landings. M. monoceros attains a maximum length of about 200 mm and has high export potential.Thus realising the growing importance of M. monoceros in the capture fisheries, it was felt, that it would be ideal to carry out detailed study on this species for rational exploitation and management of its fishery. Hence, the present work entitled, “Biology, population characteristics and fishery of the speckled shrimp Hetapenaeus monoceros (Fabricius, 1798) along Kerala coast“ was undertaken by the author. The thesis is laid out in seven chapters comprising TAXONOMY, FOOD AND FEEDING HABITS, AGE AND GROWTH, REPRODUCTION,LENGTH-WEIGHT RELATIONSHIP, FISHERY and POPULATION DYNAMICS

Influence of Frequent Flyer Programme and Airline Service Quality on Re-buy Intentions of Airline Frequent Passengers

The growth potential of service sector, especially the aviation sector in the Indian economy is splendid. Therefore, it is crucial for the airline service providers to realize their customers, design offers and deliver the desired value to their customers. This study reveals the effect of airline passenger satisfactions particularly on re-buy intentions derived from the attributes-level performance dimensions of both service aspects and loyalty programme of an airline. The mediation effect of satisfaction and other selected antecedents on the re-buy intention of a passenger is hypothesized in this study. Critical areas affecting buying intentions such as core service quality and loyalty attribute-level performances, effect of frequent flyer programme and service quality satisfaction, passenger trust on airline, brand image and moderating effects of perceived value, frequent programme status and travel frequency of airline passengers are linked in a structural model to assess the strength of each facet in affecting re-buy intentions. Implications to the airlines were made based on the finding that re-buy intentions cannot be attributed solely to the impacts of frequent flyer programme, rather affected through the mediation effect of airline service quality satisfaction, which is very much valid for the higher FFP status category of frequent travelers. The effects of moderation caused by perceived value, FFP status and flying experience were also found to be significant in making re-buy intentions.

Topological Invariants in Hydrodynamics and Hydromagnetics

In this thesis we are studying possible invariants in hydrodynamics and hydromagnetics. The concept of flux preservation and line preservation of vector fields, especially vorticity vector fields, have been studied from the very beginning of the study of fluid mechanics by Helmholtz and others. In ideal magnetohydrodynamic flows the magnetic fields satisfy the same conservation laws as that of vorticity field in ideal hydrodynamic flows. Apart from these there are many other fields also in ideal hydrodynamic and magnetohydrodynamic flows which preserves flux across a surface or whose vector lines are preserved. A general study using this analogy had not been made for a long time. Moreover there are other physical quantities which are also invariant under the flow, such as Ertel invariant. Using the calculus of differential forms Tur and Yanovsky classified the possible invariants in hydrodynamics. This mathematical abstraction of physical quantities to topological objects is needed for an elegant and complete analysis of invariants.Many authors used a four dimensional space-time manifold for analysing fluid flows. We have also used such a space-time manifold in obtaining invariants in the usual three dimensional flows.In chapter one we have discussed the invariants related to vorticity field using vorticity field two form w2 in E4. Corresponding to the invariance of four form w2 ^ w2 we have got the invariance of the quantity E. w. We have shown that in an isentropic flow this quantity is an invariant over an arbitrary volume.In chapter three we have extended this method to any divergence-free frozen-in field. In a four dimensional space-time manifold we have defined a closed differential two form and its potential one from corresponding to such a frozen-in field. Using this potential one form w1 , it is possible to define the forms dw1 , w1 ^ dw1 and dw1 ^ dw1 . Corresponding to the invariance of the four form we have got an additional invariant in the usual hydrodynamic flows, which can not be obtained by considering three dimensional space.In chapter four we have classified the possible integral invariants associated with the physical quantities which can be expressed using one form or two form in a three dimensional flow. After deriving some general results which hold for an arbitrary dimensional manifold we have illustrated them in the context of flows in three dimensional Euclidean space JR3. If the Lie derivative of a differential p-form w is not vanishing,then the surface integral of w over all p-surfaces need not be constant of flow. Even then there exist some special p-surfaces over which the integral is a constant of motion, if the Lie derivative of w satisfies certain conditions. Such surfaces can be utilised for investigating the qualitative properties of a flow in the absence of invariance over all p-surfaces. We have also discussed the conditions for line preservation and surface preservation of vector fields. We see that the surface preservation need not imply the line preservation. We have given some examples which illustrate the above results. The study given in this thesis is a continuation of that started by Vedan et.el. As mentioned earlier, they have used a four dimensional space-time manifold to obtain invariants of flow from variational formulation and application of Noether's theorem. This was from the point of view of hydrodynamic stability studies using Arnold's method. The use of a four dimensional manifold has great significance in the study of knots and links. In the context of hydrodynamics, helicity is a measure of knottedness of vortex lines. We are interested in the use of differential forms in E4 in the study of vortex knots and links. The knowledge of surface invariants given in chapter 4 may also be utilised for the analysis of vortex and magnetic reconnections.

Influence of Selected Dietary Micronutrient Elements on Growth and Biochemistry of Farmed Prawns

From the present study, it is clear that all the three metals, selenium, molybdenum and cobalt have significant effect on the antioxidant status of the shrimps. Selenium and molybdenum were observed to induce peroxidative damage at elevated levels. But at the same level, cobalt did not show such an effect. Selenium was found to be growth promoting at lower levels of dietary supplementation. Even though low levels of dietary selenium had a protective effect against the lipid peroxidation, the present study indicates that high levels of dietary selenium could promote lipid peroxidation. The selenium-dependent antioxidant enzyme, GPx behaved differently in muscle and hepatopancreas. A high concentration of selenium was required for the active expression of the enzyme in the muscle, where as in hepatopancreas maximum activity was observed at lower selenium concentration. Selenium supplementation had a positive effect on GSH concentration. The other antioxidant enzymes such as GST, SOD and CAT showed enhanced activity at higher concentration of selenium. Molybdenum supplementation significantly reduced the free radical scavenger enzymes SOD and CAT. This resulted in enhanced lipid peroxidation in tissues. The activity of antioxidant enzyme GPx and the concentration of the substrate for the enzyme, GSH also were lower at elevated levels of molybdenum supplementation. In addition to this amino acids and fatty acids were also altered in molybdenum supplemented groups. In trace amounts, dietary molybdenum exerts a beneficial effect on the growth and also in the activities of the enzymes XO and SO. At the same time it also indicates a possibility of oxidative damage as a result of the peroxidation caused by the activities of the enzymes SO and XO at elevated concentrations of molybdenum is also indicated. The absorption of various trace elements was also altered by molybdenum supplementation.Among the three metals studied, cobalt was the least toxic one at the administered levels. But this metal has a significant effect on the lipid content, amino acid composition, cholesterol levels and phospholipid levels. Increased growth was also observed as a result of cobalt supplementation in shrimps. The antioxidant system of the animal was activated by dietary cobalt. Tissue levels of the trace metals were also found to be altered in cobalt supplemented groups of shrimps.These studies, thus shows that influence of dietary trace metals calls for more detailed studies in farmed shrimp. They may hold the key to growth and even disease resistance in shrimp. But this still remains as a virgin field which demands more attention, especially in view of the increasing importance of shrimp farming.

Design and Development of data mining models for the predictions of manpower placement in the technical Domain

Data mining is one of the hottest research areas nowadays as it has got wide variety of applications in common man’s life to make the world a better place to live. It is all about finding interesting hidden patterns in a huge history data base. As an example, from a sales data base, one can find an interesting pattern like “people who buy magazines tend to buy news papers also” using data mining. Now in the sales point of view the advantage is that one can place these things together in the shop to increase sales. In this research work, data mining is effectively applied to a domain called placement chance prediction, since taking wise career decision is so crucial for anybody for sure. In India technical manpower analysis is carried out by an organization named National Technical Manpower Information System (NTMIS), established in 1983-84 by India's Ministry of Education & Culture. The NTMIS comprises of a lead centre in the IAMR, New Delhi, and 21 nodal centres located at different parts of the country. The Kerala State Nodal Centre is located at Cochin University of Science and Technology. In Nodal Centre, they collect placement information by sending postal questionnaire to passed out students on a regular basis. From this raw data available in the nodal centre, a history data base was prepared. Each record in this data base includes entrance rank ranges, reservation, Sector, Sex, and a particular engineering. From each such combination of attributes from the history data base of student records, corresponding placement chances is computed and stored in the history data base. From this data, various popular data mining models are built and tested. These models can be used to predict the most suitable branch for a particular new student with one of the above combination of criteria. Also a detailed performance comparison of the various data mining models is done.This research work proposes to use a combination of data mining models namely a hybrid stacking ensemble for better predictions. A strategy to predict the overall absorption rate for various branches as well as the time it takes for all the students of a particular branch to get placed etc are also proposed. Finally, this research work puts forward a new data mining algorithm namely C 4.5 * stat for numeric data sets which has been proved to have competent accuracy over standard benchmarking data sets called UCI data sets. It also proposes an optimization strategy called parameter tuning to improve the standard C 4.5 algorithm. As a summary this research work passes through all four dimensions for a typical data mining research work, namely application to a domain, development of classifier models, optimization and ensemble methods.

‘Modeling and Analysis of Competing Risks Data’

there has been much research on analyzing various forms of competing risks data. Nevertheless, there are several occasions in survival studies, where the existing models and methodologies are inadequate for the analysis competing risks data. ldentifiabilty problem and various types of and censoring induce more complications in the analysis of competing risks data than in classical survival analysis. Parametric models are not adequate for the analysis of competing risks data since the assumptions about the underlying lifetime distributions may not hold well. Motivated by this, in the present study. we develop some new inference procedures, which are completely distribution free for the analysis of competing risks data.

"A Study Of The Performance Of The "Jeevan Saathi" And "Jeevan Mitra” Policies Offered By The L.I.C."

The main benefit of Jeevan Saathi policy is that, it is a joint life policy which covers the life of both husband and wife under a single policy. And they also get double benefit if any one of them dies during the term of the policy. The Jeevan Mitra policy is a single life policy, the main advantage of which is that the dependents get double benefit in case of normal death and triple benefit in case of accidental death during the term of policy. so both the policies have their own attractions but when compared with the annual sales of other policies, the additional increase in the sales of these policies are decreasing. It is a fact finding study concerned with market performance of these two policies by conducting a survey among the Jeevan Saathi and Jeevan Mitra policy holders, and a thorough analysis of the various information or data collected from them. This study is an attempt to present an integrated picture of the main features of the policy holders who have bought these policies, the major factors responsible for making them purchase these policies, the various difficulties faced by them at present and further modification needed in the plans of these policies according to the opinion of policy holders. For increasing accuracy of the conclusions, information is also collected from Agents and Development Officers by using interview schedule. The main purpose of this study is to draw attention of LIC to introduce new plans of policies taking into consideration the drawbacks or defects of the existing policies and present needs of policy holders. It will also help to make new plans in order to suit the needs of more people who want to buy life insurance policies