Abstract

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Summer

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Polymeric thin films for integrated optics.

This thesis presents the results from the characterisation of the linear optical properties of various polymers and the energy transfer process between several dye pairs in polymeric waveguides. The polymers and dyes were considered for their use in solid state thin film wavelength tuneable light sources. The optical waveguiding properties of the polymers were investigated, and the results of the experiments are reported. Also the fundamental concepts of wave guiding in thin films are presented. The techniques of processing the thin films, input and output coupling of the light and analysis of the results is discussed. The mechanism of non-radiative energy transfer between dye pairs was investigated as a means of efficiently exciting the acceptor dye. The theory is discussed. Also the results of both the steady state and time resolved experiments, used to determine the efficiency of the process, are reported. Efficient energy transfer has been observed in a rhodamine dye system and also between newly developed BASF dyes. Several models are proposed to explain an up conversion observed in a dye doped polymer waveguide. Here fluorescence was observed by exciting the dye in the long wavelength tail of the absorption band. A model based on the thermal population of electrons to higher vibrational levels, from where they can be promoted to the first excited electronic state, is shown to best explain the phenomenon

Modeling Travel Demand in a Metropolitan City: Case Study of Bangalore, India

Increasing urbanization, population growth and rising incomes have led to rapid growth of travel demand in Indian cities. The paper provides a modeling approach for forecasting urban travel demand and assessing public transport options for large metropolitan cities. A travel characteristics model is used to forecast the pattern of travel demand in Bangalore city up to the year 2014. The paper examines the scope of a public bus transport service and a mass rapid transit system for meeting the projected travel demand and thereby curtailing the growth of personal vehicles in the city.

Emission of Green House Gases from Grasslands and their Mitigation

The concentrations of green house gases (GHG) in the atmosphere began in pre-industrial times and it continues to increase. This could result into an alarming increase in temperature of up to 5.4 oC by year 2100 due to a net global annual GHG emission of H 4.5-6.5 Gt C equivalent. About 18% of the world’s GHG are contributed by livestock and related activities on grasslands that are spread over almost 35 million Km2.These grasslands give livelihood to over a billion people most of who are poor. Twenty to 70% of the land surface area is degrading often due to overgrazing caused by increased demand for meat and milk, among other factors. A right set of policies that incentivises appropriate management of the grasslands have the potential to reduce up to 30% of the GHG globally. This can be achieved by mainly focussing on reduction in deforestation for pastures, silvo-pastoral improvements and reduction in enteric fermentation in animals, and appropriate manure and fertilizer management, especially on extensive grasslands. Reduction in GHG emissions will also depend upon the level of resource use efficiencies achieved, added intensification to reduce pressure on grasslands, and success or failure of appropriate market and regulatory policy interventions

Data Visualization and Techniques

Data visualization is the graphical representation of information. Bar charts scatter graphs, and maps are examples of simple data visualizations that have been used for decades. Information technology combines the principles of visualization with powerful applications and large data sets to create sophisticated images and animations. A tag cloud, for instance, uses text size to indicate the relative frequency of use of a set of terms. In many cases, the data that feed a tag cloud come from thousands of Web pages, representing perhaps millions ofusers. All of this information is contained in a simple image that you can understand quickly and easily. More complex visualizations sometimes generate animations that demonstrate how data change over time. In an application called Gap minder, bubbles represent the countriesof the world, with each nationÊs population reflected in the size of its bubble. You can set the x and y axes to compare life expectancy with per capita income, for example, and the tool will show how each nationÊs bubble moves on the graph over time. You can see that higher income generallycorrelates with longer life expectancy, but the visualization also clearly shows that China doesnÊt follow this trend·in 1975, the country had one of the lowest per capita incomes but one of the longer life expectancies. The animation also shows the steep drop in life expectancy in many sub-Saharan African countries starting in the early 1990s (corresponding to the AIDS epidemic in that part of the world) and the plummeting of life expectancy in Rwanda at the time of that nationÊs genocide

Water production function of maize for Northeast Brazil

Estudou-se, através de um experimento em blocos ao acaso, os efeitos de quatro níveis de nitrogênio, em diferentes condições de umidade, sobre os estágios de crescimento, embonecamento, formação de grãos e produtividade do milho (Zea mays L.) e as relações entre a produtividade e os três primeiros estágios. Os fatores da resposta de produção baseados na equação de Doorenbos e Kassam variaram acentuadamente, não só com os diferentes estágios de crescimento, mas, também, com os diferentes níveis de nitrogênio e os diferentes níveis de água. Assim, esta equação não pareceu ser válida para explicar a resposta de produtividade a níveis de água. Sugeriu-se uma equação linear modificada. Nesta equação, a intercessão K1 e inclinação K2 são os fatores da resposta de produção. Estes fatores para a cultura do milho foram desenvolvidos para todos os quatro estágios de crescimento e níveis de nitrogênio. Pode-se obter uma eficiência média do uso de água, em termos de produtividade, de, aproximadamente, 57,5 kg/ha-cm de água, sendo, contudo, pequeno o incremento, em face dos níveis crescentes de nitrogênio aplicado até 120 kg/ha. Os coeficientes de cultura (Kc) calculados estão muito abaixo da estimativa da FAO, para todos os níveis de nitrogênio. Por essa razão, deve haver considerável economia de água se estes coeficientes forem usados em lugar da estimativa da FAO. A informação mostrada pode imediatamente ser utilizada para turno de irrigação e para projetos de irrigação suplementar planejado para as condições do Nordeste do Brasil.The results of the randomized block experiment with four growth stages and four nitrogen levels to determine the water production function of maize (Zea mays L.) for Northeast Brazilian conditions are reported. The yield response factors as per Doorenbos and Kassam's equation are found to vary drastically not only for different growth stages but also with different nitrogen levels and with different water levels. Thus, this equation is not a true representation of yield response to water. A modified linear equation with an intercept (K2) has been suggested. The coefficients of this modified equation (intercept K1 and the slope K2) are the modified yield response factors. These factors for maize have been developed here for all the four stages and for all the four nitrogen levels. The average highest water use efficiency of approximately 57.5 kg/ha-cm of water can be obtained but it shows no increase with increase in applied nitrogen up to 120 kg/ha. Finally crop coefficients (K c) have been calculated. The overall values of Kc are much below the FAO estimates for all nitrogen levels. All the above information developed here will help in better irrigation scheduling and better planning of supplemental irrigation projects in the Northeast Brazil

RNA interference- a novel approach for plant disease management

RNA interference (RNAi) is an incredible revolution in the field of functional genomics, a breakthrough in plant molecular genetics. This technology will generate enormous potential for engineering control of gene expres-sion. The success of managing biotic stress using RNAi technology will prove to be biologically and environmentally safe. It is therapeutic in approach as the resistance induced by RNAi is triggered by ds RNA that results in silencing of specific genes before being translated in a homology dependent manner. Over the time, RNAi is significantly proving it as one of the most promiscent management strategy which eliminates certain risks associated with the development of transgenic plants. This review gives an insight into the probability of management of plant diseases caused by various biotic agents viz. fungi, bacteria and viruses using RNA interference technique and host-pathogen related targeted sites

A review on persisting threats to snail’s diversity and its conservation approaches

Snails are important part of our terrestrial, freshwater and marine ecosystems. They are molluscian members having their effective role in biomonitoring, nutrient cycling and medicinal development. They are integral part of food chain system and have direct or indirect impact in maintaining ecological functioning. Besides their importance, they are documented with largest extinction rate as compared to other existed taxa. This is due to the fact that, unexploration and poor attention has been given in the research and development by the scientific world. Till now, a little information is available related to systematics, life history, population biology, threats and conservation status of these slimy organisms. This paper briefly reviews the diversity of terrestrial, freshwater and marine snails with the existed threats with their conservation approaches which may proved to be fruitful in developing awareness related to the snails in the society

RNA interference: A novel tool for plant disease management

Plant diseases pose a huge threat to crop production globally. Variations in their genomes cause selection to favor those who can survive pesticides and Bacillus thuringiensis (Bt) crops. Though plant breeding has been the classical means of manipulating the plant genome to develop resistant cultivar for controlling plant diseases, the advent of genetic engineering provides an entirely new approach being pursued to render plants resistant to fungi, bacteria, viruses and nematodes. RNA interference (RNAi) technology has emerged to be a promising therapeutic weapon to mitigate the inherent risks such as the use of a specific transgene, marker gene, or gene control sequences associated with development of traditional transgenics. Silencing specific genes by RNAi is a desirable natural solution to this problem as disease resistant transgenic plants can be produced within a regulatory framework. Recent studies have been successful in producing potent silencing effects by using target doublestranded RNAs through an effective vector system. Transgenic plants expressing RNAi vectors, as well as, dsRNA containing crop sprays have been successful for efficient control of plant pathogens affecting economically important crop species. The present paper discusses strategies and applications of this novel technology in plant disease management for sustainable agriculture production.Keywords: Plant disease, RNA interference, transgene, managementAfrican Journal of Biotechnology Vol. 12(18), pp. 2303-231