19 resultados para Functions of covariance

em Cochin University of Science


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The brain with its highly complex structure made up of simple units,imterconnected information pathways and specialized functions has always been an object of mystery and sceintific fascination for physiologists,neuroscientists and lately to mathematicians and physicists. The stream of biophysicists are engaged in building the bridge between the biological and physical sciences guided by a conviction that natural scenarios that appear extraordinarily complex may be tackled by application of principles from the realm of physical sciences. In a similar vein, this report aims to describe how nerve cells execute transmission of signals ,how these are put together and how out of this integration higher functions emerge and get reflected in the electrical signals that are produced in the brain.Viewing the E E G Signal through the looking glass of nonlinear theory, the dynamics of the underlying complex system-the brain ,is inferred and significant implications of the findings are explored.

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The study is a close scrutiny of the process of investigation of offences in India along with an analysis of powers and functions of the investigating agency. The offences, which are prejudicial to sovereignty, integrity and security of the nation or to its friendly relations with foreign states, are generally called the offences against national security. Offences against national security being prejudicial to the very existence of the nation and its legal system, is a heinous and terrible one. As early as 1971 the Law Commission of India had pointed out the need of treating the offences relating to national security and their perpetrators on a totally different procedural footing. The recommendation that, all the offences coming under the said category ought to be brought under the purview of a single enactment so as to confront such offences effectively. The discrepancies in and inadequacies of the criminal justice system in India as much as they are related to the investigations of the offences against national security are examined and the reforms are also suggested. The quality of criminal justice is closely linked with the caliber of the prosecution system and many of the acquittals in courts can be ascribed not only to poor investigations but also to poor quality of prosecution.

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This study is about the stability of random sums and extremes.The difficulty in finding exact sampling distributions resulted in considerable problems of computing probabilities concerning the sums that involve a large number of terms.Functions of sample observations that are natural interest other than the sum,are the extremes,that is , the minimum and the maximum of the observations.Extreme value distributions also arise in problems like the study of size effect on material strengths,the reliability of parallel and series systems made up of large number of components,record values and assessing the levels of air pollution.It may be noticed that the theories of sums and extremes are mutually connected.For instance,in the search for asymptotic normality of sums ,it is assumed that at least the variance of the population is finite.In such cases the contributions of the extremes to the sum of independent and identically distributed(i.i.d) r.vs is negligible.

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In this project, an attempt has been made to study the stability of erythrocyte and lysosomal membranes biochemically. Erythrocytes were chosen for the study because of their ready availability and relative simplicity. Biological membranes forming closed boundaries between compartments of varying composition consist mainly of proteins and lipids. They are asymmetric, fluid structures that are thermodynamically stable and metabolically active. Normal cellular function begins with normal membrane structure and any variation in it may upset the normal functions. The degree of fluidity of a membrane depends on the chain length of its lipids and degree of unsaturation of constituent fatty acids. In response to environmental changes, many cells can regulate composition of their membranes to maintain the overall semi fluid environment necessary for many membrane associated functions. The assembly and Maintenance of membrane structures in cells is a dynamic process. The components are not only synthesized and inserted into a growing membrane but are also continuously degraded at a slower rate. This turnover process varies with each individual molecule.Lysosomes are important in the catabolic processes occurring in the cell. Lysosomes contain hydrolytic enzymes and are stable under normal conditions. In certain pathological conditions, the lysosomal membrane may rupture, releasing the hydrolytic enzymes into the cell and digestion of cell takes place as a whole. This is very dangerous. In normal life processes of multi cellular organisms, lysosomes rupture following the death of a cell and it may have some value as a built in mechanism for selfremoval of dead cells.An attempt has also been made in this project towards developing lysosome membrane stability as an index of fish spoilage during storage. Different membranes within the cell and between cells have different compositions as reflected in the ratio of protein to lipid. The difference is not surprising given the very different functions of membranes

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Optical emission studies of C2 molecules in plasma obtained by Nd:YAG laser ablation of graphite in a helium atmosphere are reported for irradiances in the range (1–9:2/ x 1010 W cm−2. The characteristics of the spectral emission intensity from the C2 (Swan band) species have been investigated as functions of the distance from the target, ambient pressure and laser irradiance. Estimates of vibrational temperatures of C2 species under various irradiance conditions are made. Results of measurements performed under different ambient helium gas pressures are also discussed.

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Optical emission studies of C2 molecules in plasma obtained by Nd:YAG laser ablation of graphite in a helium atmosphere are reported for irradiances in the range (1–9:2/ x 1010 W cm−2. The characteristics of the spectral emission intensity from the C2 (Swan band) species have been investigated as functions of the distance from the target, ambient pressure and laser irradiance. Estimates of vibrational temperatures of C2 species under various irradiance conditions are made. Results of measurements performed under different ambient helium gas pressures are also discussed.

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Ship recycling has been considered as the best means to dispose off an obsolete ship. The current state of art of technology combined with the demands of sustainable developments from the global maritime industrial sector has modified the status of erstwhile ‘ship breaking’ involving ship scrap business to a modern industry undertaking dismantling of ships and recycling/reusing the dismantled products in a supply chain of pre owned product market by following the principles of recycling. Industries will have to formulate a set of best practices and blend them with the engineering activities for producing better quality products, improving the productivity and for achieving improved performances related to sustainable development. Improved performance by industries in a sustainable development perspective is accomplished only by implementing the 4E principles, ie.,. ecofriendliness, engineering efficiency, energy conservation and ergonomics in their core operations. The present study has done a comprehensive investigation into various ship recycling operations for formulating a set of best practices.Being the ultimate life cycle stage of a ship, ship recycling activities incorporate certain commercial procedures well in advance to facilitate the objectives of dismantling and recycling/reusing of various parts of the vessel. Thorough knowledge regarding these background procedures in ship recycling is essential for examining and understanding the industrial business operations associated with it. As a first step, the practices followed in merchant shipping operations regarding the decision on decommissioning have been and made available in the thesis. Brief description about the positioning methods and important preparations for the most feasible ship recycling method ie.,. beach method have been provided as a part of the outline of the background information. Available sources of guidelines, codes and rules & regulations for ship recycling have been compiled and included in the discussion.Very brief summary of practices in major ship recycling destinations has been prepared and listed for providing an overview of the global ship recycling activities. The present status of ship recycling by treating it as a full fledged engineering industry has been brought out to establish the need for looking into the development of the best practices. Major engineering attributes of ship as a unique engineering product and the significant influencing factors on her life cycle stage operations have been studied and added to the information base on ship recycling. Role of ship recycling industry as an important player in global sustainable development efforts has been reviewed by analysing the benefits of ship recycling. A brief synopsis on the state of art of ship recycling in major international ship recycling centres has also been incorporated in the backdrop knowledgebase generation on ship recycling processes.Publications available in this field have been reviewed and classified into five subject categories viz., Infrastructure for recycling yards and methods of dismantling, Rules regarding ship recycling activities, Environmental and safety aspects of ship recycling, Role of naval architects and ship classification societies, Application of information technology and Demand forecasting. The inference from the literature survey have been summarised and recorded. Noticeable observations in the inference include need of creation of a comprehensive knowledgebase on ship recycling and its effective implementation in the industry and the insignificant involvement of naval architects and shipbuilding engineers in ship recycling industry. These two important inferences and the message conveyed by them have been addressed with due importance in the subsequent part of the present study.As a part of the study the importance of demand forecasting in ship recycling has been introduced and presented. A sample input for ship recycling data for implementation of computer based methods of demand forecasting has been presented in this section of the thesis.The interdisciplinary nature of engineering processes involved in ship recycling has been identified as one of the important features of this industry. The present study has identified more than a dozen major stake holders in ship recycling having their own interests and roles. It has also been observed that most of the ship recycling activities is carried out in South East Asian countries where the beach based ship recycling is done in yards without proper infrastructure support. A model of beach based ship recycling has been developed and the roles, responsibilities and the mutual interactions of the elements of the system have been documented as a part of the study Subsequently the need of a generation of a wide knowledgebase on ship recycling activities as pointed out by the literature survey has been addressed. The information base and source of expertise required to build a broad knowledgebase on ship recycling operations have been identified and tabulated. Eleven important ship recycling processes have been identified and a brief sketch of steps involved in these processes have been examined and addressed in detail. Based on these findings, a detailed sequential disassembly process plan of ship recycling has been prepared and charted. After having established the need of best practices in ship recycling initially, the present study here identifies development of a user friendly expert system for ship recycling process as one of the constituents of the proposed best practises. A user friendly expert system has been developed for beach based ship recycling processes and is named as Ship Recycling Recommender (SRR). Two important functions of SRR, first one for the ‘Administrators’, the stake holders at the helm of the ship recycling affairs and second one for the ‘Users’, the stake holders who execute the actual dismantling have been presented by highlighting the steps involved in the execution of the software. The important output generated, ie.,. recommended practices for ship dismantling processes and safe handling information on materials present onboard have been presented with the help of ship recycling reports generated by the expert system. A brief account of necessity of having a ship recycling work content estimation as part of the best practices has been presented in the study. This is supported by a detailed work estimation schedule for the same as one of the appendices.As mentioned earlier, a definite lack of involvement of naval architect has been observed in development of methodologies for improving the status of ship recycling industry. Present study has put forward a holistic approach to review the status of ship recycling not simply as end of life activity of all ‘time expired’ vessels, but as a focal point of integrating all life cycle activities. A new engineering design philosophy targeting sustainable development of marine industrial domain, named design for ship recycling has been identified, formulated and presented. A new model of ship life cycle has been proposed by adding few stages to the traditional life cycle after analysing their critical role in accomplishing clean and safe end of life and partial dismantling of ships. Two applications of design for ship recycling viz, recyclability of ships and her products and allotment of Green Safety Index for ships have been presented as a part of implementation of the philosophy in actual practice.

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YBa2Cu307 target was laser ablated, and the time-of-flight (TOF) distributions of Y, Y+., and YO in the resultant plasma were investigated as functions of distance from the target and laser energy density using emission spectroscopy. Up to a short distance from the target (-1.5 cm), TOF distributions show twin peaks for Y and YO, while only single-peak distribution is observed for Y+. At greater distances (>1.5 cm) all of them exhibit single-peak distribution. The twin peaks are assigned to species corresponding to those generated directly/m the vicinity of target surface and to those generated from collisional/recombination process.

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Time and space resolved studies of emission from CN molecules have been carried out in the plasma produced from graphite target by 1.06 urn pulses from a Q-switched Nd:YAG laser. Depending on the laser pulse energy, time of observation and position of the sampled volume of the plasma, the features of the emission spectrum are found to change drastically. The vibrational temperature and population distribution in the different vibrational levels have been studied as functions of distance, time, laser energy and ambient gas pressure. Evidence for nonlinear effects of the plasma medium such as self focusing which exhibits threshold-like behaviour are also obtained. Temperature and electron density of the plasma have been evaluated using the relative line intensities of successive ionization stages of carbon atom. These electron density measurements are verified by using Stark broadening method.

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The objective of the study isto determine the average quantity of certain biochemical constituents of the haemolymph of Penaeus indicus and to verify the importanceof the simple correlation between the quantity or content of the biochemical constituents in the haemolymph and the size of the species, sex, moult and reproductive stages. The biochemical constituents studied are protein, free amino acids, glucose, total lipids, cholesterol, calcium, zinc, iron and manganese. The study Identifies the species specific haemolymph protein pattern by electrophoresis and determines the qualitative variations of haemolymph proteins with respect to sex, size, moult and reproductive stages. Major protein components such as hemocyanin and female specific protein are determined with a view to understand their function. The thesis also identifies the circulating haemocytes with a view to understand their specific role in the various physiological functions of the species. The thesis is presented in three chapters. Each chapter has an introduction to the particular aspect of study which includes a review of literature, methodology adopted for the study, the results obtained and discussion on the subject. The first Chapter deals with the biochemical constituents of the haemolymph, the second includes electrophoretic characterization of proteins in the haemolymph and the third Chapter deals with haemocyte identification and classification. A summary of the thesis and literature cited in the text are listed at the end.

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The study is undertaken by the researcher with the object of examining the remuneration pattern of executive personnel in the manufacturing public enterprises in Kerala so as to find out whether there is any rationale or criteria involved in remunerating executives. It is also envisaged to find out the pattern of executive remuneration in the various categories of industries and inter—industry disparities among the public sector enterprises. This is considered to be a very fruitful area for investigation, particularly in view of the generally prevailing notion that public sector executives in Kerala are not remunerated properly and glaring inequalities and disparities are existing among the various categories of industries and within the same industry. Therefore the study is to explore the criteria used for the determination of executive remuneration and the relative weightage of various factors such as size of the firm, rate of return sales volume etc of the organisation and various other factors such as qualification, experience, level of job and functions of executives. Further the study is extended to find out the role of 'pay' towards motivation and efficiency of the executive personnel

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This makes a thorough study of Role of Academic Bodies with Special Reference to the Academic Programmes in the Universities in Kerala. The present study has dealt with the constitution, powers and functions of the authorities of the universities in Kerala, especially the academic bodies which have well-defined powers and function. This thesis gives in detail the role and functions of the academic bodies in the four universities in Kerala, under study: and examines the role-effectiveness of these bodies. To sum up, it can be concluded that the academic bodies in the universities in Kerala do not function as effectively as envisaged in the laws of the universities. They have a maintenance-oriented approach rather than a dynamic one, without thinking in terms of introducing innovations. They need improvement in the various aspects of their constitution, selection of members and their mode of functioning

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In this thesis we investigate some problems in set theoretical topology related to the concepts of the group of homeomorphisms and order. Many problems considered are directly or indirectly related to the concept of the group of homeomorphisms of a topological space onto itself. Order theoretic methods are used extensively. Chapter-l deals with the group of homeomorphisms. This concept has been investigated by several authors for many years from different angles. It was observed that nonhomeomorphic topological spaces can have isomorphic groups of homeomorphisms. Many problems relating the topological properties of a space and the algebraic properties of its group of homeomorphisms were investigated. The group of isomorphisms of several algebraic, geometric, order theoretic and topological structures had also been investigated. A related concept of the semigroup of continuous functions of a topological space also received attention

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Culturing of fish in captivity demands a detailed knowledge on well balanced diet and adequate feeding. Formulation and production of nutritionally balanced diets for fish require research, quality control and biological evaluation. It is often assuemed that what is ingested is also digested, but this is not always be the case. Digestion depends upon both the physical state of the food and the kind and quantity of enzymes in the digestive tract. The ability of fish to digest a particular component of diet can be ascertained by investigating the complement of digestive enzymes present along the digestive tract. Investigations on the basic digestive physiology will not only enhance our present knowledge on nutrition and feed development, but will also contribute in understanding the digestive functions of lower vertebrates. It is against this background that the present topic of investigation "Studies on the digestive enzymes of the cultivable grey mullet Liza parsia Hamilton Buchanan, l822" has been selected. The thesis is arranged and presented in eight chapters.

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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.