998 resultados para diversity exchange


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Ion-exchange chromatography has emerged as a practical and rapid method of separation and analysis. A review of literature on chelating resins reveals that eventhough investigations on highly selective resins are intensively pursued from early 1940s, such resins are still insufficiently used in analytical chemistry and process technology. This is mainly due to the complexity of their synthesis and high cost. In this context, it is worthwhile to develop novel chelating resins which are specific or at least selective towards a group of metal ions. Synthesis, characterization and analytical applications of two such resins are presented in this thesis.

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Investigations on the water relations and gas exchange of/tcacia aun'culiji_2rmis were carried out in natural and controlled environments. The experiments were performed in both seedlings and five year old trees. Different sets of experiments were conducted in Acacia plantations, at Kothachira, Palakkad District and in .seedlings, at KFRI campus nursery mainly during the summer months. Investigations were also extended to seedlings of A.mangium, Aaulacocarpa and /Lholocericea, which are also phyllodinous species with the intention of comparing their physiology with Acacia auriculifomus. Potted seedlings of four species of Acacia viz., A. auriculi/E)/7r:i.r, /I. aulacocarpa, A. holocericea and A. mangium were used for the study. Measurements of relative water content (RWC), water potential, photosynthetic rate, transpiration, stomatal conductance, water use efficiency etc. of phyllodes were measured diumally in plants subjected to three stress conditions namely, drought, salinity and flooding

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Emergence of antibiotic resistance among aquaculture pathogens has made it necessary to look into environment friendly, effective and sustainable methods such as probiotic and immunostimulants among others.. In the present study, LAB were isolated from the gut of fish species namely Rastrelliger kanagurta and analyzed for their antibacterial activity against various fish, shrimp and human pathogens. Different LAB species such as Lactobacillus plantarum, L. bulgaricus, L. brevis and L. viridiscens were encountered in the gut of R. kanagurta. Several strains showed good activity against fish, shrimp and human pathogens. LAB from the gut of such marine species may be developed as possible probiont for environment friendly health management of fresh water, estuarine and marine species currently exploited in aquaculture

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In the present study we address the issue on gut associated lactic acid bacteria (LAB) isolated from the intestine of estuarine fish Mugil cephalus using de Man Rogossa and Sharpe (MRS) agar. LAB isolates were identified biochemically and screened for their ability to inhibit in vitro growth of various fish, shrimp and human pathogens. Most of the LAB isolates displayed an improved antagonism against fish pathogens compared to shrimp and human pathogens. Selected representative strains displaying high antibacterial activity were identified using 16S rRNA gene sequence analysis. Of the selected strains Lactobacillus brevis was the most predominant. Four other species of Lactobacillus, Enterobacter hormaechei and Enterobacter ludwigii were also identified. It was also observed that even among same species, considerable diversity with respect to substrate utilization persisted. Considering the euryhaline nature of grey mullet (Mugil cephalus), the LAB isolated from the gut possessed good tolerance to varying salt concentrations. This finding merits further investigation to evaluate whether the isolated LAB could be used as probiotics in various fresh and sea water aquaculture

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The diversity and load of heterotrophic bacteria and fungi associated with the mangrove soil from Suva, Fiji Islands, was determined by using the plate count method. The ability of the bacterial isolates to produce various hydrolytic enzymes such as amylase, gelatinase and lipase were determined using the plate assay. The heterotrophic bacterial load was considerably higher than the fungal load. There was a predominance of the gram positive genus, Bacillus. Other genera encountered included Staphylococcus, Micrococcus, Listeria and Vibrio. Their effectiveness on the degradation of commercial polythene carry bags made of high density polyethylene (HDPE) and low density polyethylene (LDPE) was studied over a period of eight weeks in the laboratory. Biodegradation was measured in terms of mean weight loss, which was nearly 5 % after a period of eight weeks. There was a significant increase in the bacterial load of the soil attached to class 2 (HDPE) polythene. After eight weeks of submergence in mangrove soil, soil attached to class 1 and class 3 polythene mostly had Bacillus (Staphylococcus predominated in class 2 polythene). While most of the isolates were capable of producing hydrolytic enzymes such as amylase and gelatinase, lipolytic activity was low. Class 2 HDPE suffered the greatest biodegradation.

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Diversity of different groups of Bacillus and Actinomycetes in the water and sediment samples from kumarakom estuary was analysed to find out potential strains for further application. Bacillus genera was identified and grouped into five phenogroups .Phenogroups show differences in the shape of the spore,position of the spore,and swelling of the sporangium.Ability of the isolates to elaborate various hydrolytic enzymes and their ability to reduce nitrate and ferment various carbohydrate sources were also studied.

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Here we investigate the diversity of pathogenic Vibrio species in marine environments close to Suva, Fiji. We use four distinct yet complementary analyses – biochemical testing, phylogenetic analyses, metagenomic analyses and molecular typing – to provide some preliminary insights into the diversity of vibrios in this region. Taken together our analyses confirmed the presence of nine Vibrio species, including three of the most important disease-causing vibrios (i.e. V. cholerae, V. parahaemolyticus and V. vulnificus), in Fijian marine environments. Furthermore, since toxigenic V. parahaemolyticus are present on fish for consumption we suggest these bacteria represent a potential public health risk. Our results from Illumina short read sequencing are encouraging in the context of microbial profiling and biomonitoring. They suggest this approach may offer an efficient and costeffective method for studying the dynamics of microbial diversity in marine environments over time.

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Professor Irma Glicman Adelman, an Irish Economist working in California University at Berkely, in her research work on ‘Development Over Two Centuries’, which is published in the Journal of Evolutionary Economics, 1995, has identified that India, along with China, would be one of the largest economies in this 21st Century. She has stated that the period 1700 - 1820 is the period of Netherlands, the period 1820 - 1890 is the period of England the period 1890 - 2000 is the period of America and this 21st Century is the century of China and India. World Bank has also identified India as one of the leading players of this century after China. India will be third largest economy after USA and China. India will challenge the Global Economic Order in the next 15 years. India will overtake Italian economy in 2015, England economy in 2020, Japan economy in 2025 and USA economy in 2050 (China will overtake Japan economy in 2016 and USA economy in 2027). India has the following advantages compared with other economies. India is 4th largest GDP in the world in terms of Purchasing Power. India is third fastest growing economy in the world after China and Vietnam. Service sector contributes around 57% of GDP. The share of agriculture is around 17% and Manufacture is 16% in 2005 - 2006. This is a character of a developed country. Expected GDP growth rate is 10% shortly (It has come down from 9.2% in 2006 - 2007 to 6.2% during 2008 - 2009 due to recession. It is only a temporary phenomenon). India has $284 billion as Foreign Exchange Reserve as on today. India had just $1 billion as Foreign Exchange Reserve when it opened its economy in the year 1991. In this research paper an attempt has been made to study the two booming economies of the globe with respect to their foreign exchange reserves. This study mainly based on secondary data published by respective governments and various studies done on this area

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The magnetic properties of amorphous Fe–Ni–B based metallic glass nanostructures were investigated. The nanostructures underwent a spin-glass transition at temperatures below 100 K and revealed an irreversible temperature following the linear de Almeida–Thouless dependence. When the nanostructures were cooled below 25 K in a magnetic field, they exhibited an exchange bias effect with enhanced coercivity. The observed onset of exchange bias is associated with the coexistence of the spin-glass phase along with the appearance of another spin-glass phase formed by oxidation of the structurally disordered surface layer, displaying a distinct training effect and cooling field dependence. The latter showed a maximum in exchange bias field and coercivity, which is probably due to competing multiple equivalent spin configurations at the boundary between the two spin-glass phases

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Present study consists the species diversity, abundance and community structure of ichthyofauna in the seagrass meadow of Minicoy Atoll, Lakshadweep Islands. Two hundred and three species of fishes were recorded during the study, from four stations in the Atoll. They belonged to 2 classes, 11orders, 43 families and 93 genera. Six species belonged to the class Chondreichthyes and 197 species to Osteichthyes. Family Pomacentridae showed maximum abundance of species (22%). Station I, having close proximity to the coral reefs, observed the maximum number of families (37) and species (129) and that with minimum number was in station II (23 families and 52 species). Bray-Curtis similarity plot showed a similarity range of 22 to 52%, seasonally. Station I showed highest Shannon-Wiener diversity index (H’log2) (4.22) during August and the lowest (2.91) during June. Stations I and III showed comparatively higher abundance and diversity of fishes. Variability in seagrass habitat structure and the interaction with coral reefs influenced the species composition and diversity of fishes in Minicoy Atoll. The findings of the present investigation can be used as baseline information for the fishery resource management of the region

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Among the decapod crustaceans, brachyuran crabs or the true crabs occupy a very significant position due to their ecological and economic value. Crabs support a sustenance fishery in India, even though their present status is not comparable to that of shrimps and lobsters. They are of great demand in the domestic market as well as in the foreign markets. In addition to this, brachyuran crabs are of great ecological importance. They form the conspicuous members of the mangrove ecosystems and play a significant role in detritus formation, nutrient recycling and dynamics of the ecosystem. Considering all these factors, crabs are often considered to be the keystone species of the mangrove ecosystem. Though several works have been undertaken on brachyuran crabs world –wide as well as within the country, reports on the brachyuran crabs of Kerala waters are very scanty. Most of the studies done on brachyuran fauna were from the east coast of India and a very few works from the west coast. Among the edible crabs, mud crabs belonging to genus Scylla forms the most important due to their large size and taste. They are being exported on a large scale to the foreign markets like Singapore, Malaysia and Hong Kong. Kerala is the biggest supplier of live mud crabs and Chennai is the major centre of live mud crab export. However, there exists considerable confusion regarding the identification of mud crabs because of the subtle morphological differences between the species.In this context, an extensive study was undertaken on the brachyuran fauna of Cochin Backwaters, Kerala, India, to have a basic knowledge on their diversity, habitat preference and systematics. The study provides an attempt to resolve the confusion pertaining in the species identification of mud crabs belonging to Genus Scylla. Diversity study revealed the occurrence of 23 species of brachyuran crabs belonging to 16 genera and 8 families in the study area Cochin Backwaters. Among the families, the highest number of species was recorded from Family Portunidae .Among the 23 crab species enlisted from the Cochin backwaters, 5 species are of commercial importance and contribute a major share to the crustacean fishery of the Cochin region. It was observed that, the Cochin backwaters are invaded by certain marine migrant species during the Post monsoon and Pre monsoon periods and they are found to disappear with the onset of monsoon. The study reports the occurrence of the ‘herring bow crab’ Varuna litterata in the Cochin backwaters for the first time. Ecological studies showed that the substratum characteristics influence the occurrence, distribution and abundance of crabs in the sampling stations rather than water quality parameters. The variables which affected the crab distribution the most were Salinity, moisture content in the sediment, organic carbon and the sediment texture. Besides the water and sediment quality parameters, the most important factor influencing the distribution of crabs is the presence of mangroves. The study also revealed that most of the crabs encountered from the study area preferred a muddy substratum, with high organic carbon content and high moisture content. In the present study, an identification key is presented for the brachyuran crabs occurring along the study area the Cochin backwaters and the associated mangrove patches, taking into account the morphological characters coupled with the structure of third maxillipeds, first pleopods of males and the shape of male abdomen. Morphological examination indicated the existence of a morphotype which is comparable with the morphological features of S. tranquebarica, the morphometric study and the molecular analyses confirmed the non existence of S. tranquebarica in the Cochin backwaters.

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Little is known about plant biodiversity, irrigation management and nutrient fluxes as criteria to assess the sustainability of traditional irrigation agriculture in eastern Arabia. Therefore interdisciplinary studies were conducted over 4 yrs on flood-irrigated fields dominated by wheat (Triticum spp.), alfalfa (Medicago sativa L.) and date palm (Phoenix dactylifera L.) in two mountain oases of northern Oman. In both oases wheat landraces consisted of varietal mixtures comprising T. aestivum and T. durum of which at least two botanical varieties were new to science. During irrigation cycles of 6-9 days on an alfalfa-planted soil, volumetric water contents ranged from 30-13%. For cropland, partial oasis balances (comprising inputs of manure, mineral fertilizers, N2-fixation and irrigation water, and outputs of harvested products) were similar for both oases, with per hectare annual surpluses of 131 kg N, 37 kg P and 84 kg K at Balad Seet and of 136 kg N, 16 kg P and 66 kg K at Maqta. Respective palm grove surpluses, in contrast were with 303 kg N, 38 kg P, and 173 kg K ha^-1 yr^-1 much higher at Balad Seet than with 84 kg N, 14 kg P and 91 kg K ha^-1 yr^-1 at Maqta. The results show that the sustainability of these irrigated landuse systems depends on a high quality of the irrigation water with low Na but high CaCO3, intensive recycling of manure and an elaborate terrace structure with a well tailored water management system that allows adequate drainage.

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Context awareness, dynamic reconfiguration at runtime and heterogeneity are key characteristics of future distributed systems, particularly in ubiquitous and mobile computing scenarios. The main contributions of this dissertation are theoretical as well as architectural concepts facilitating information exchange and fusion in heterogeneous and dynamic distributed environments. Our main focus is on bridging the heterogeneity issues and, at the same time, considering uncertain, imprecise and unreliable sensor information in information fusion and reasoning approaches. A domain ontology is used to establish a common vocabulary for the exchanged information. We thereby explicitly support different representations for the same kind of information and provide Inter-Representation Operations that convert between them. Special account is taken of the conversion of associated meta-data that express uncertainty and impreciseness. The Unscented Transformation, for example, is applied to propagate Gaussian normal distributions across highly non-linear Inter-Representation Operations. Uncertain sensor information is fused using the Dempster-Shafer Theory of Evidence as it allows explicit modelling of partial and complete ignorance. We also show how to incorporate the Dempster-Shafer Theory of Evidence into probabilistic reasoning schemes such as Hidden Markov Models in order to be able to consider the uncertainty of sensor information when deriving high-level information from low-level data. For all these concepts we provide architectural support as a guideline for developers of innovative information exchange and fusion infrastructures that are particularly targeted at heterogeneous dynamic environments. Two case studies serve as proof of concept. The first case study focuses on heterogeneous autonomous robots that have to spontaneously form a cooperative team in order to achieve a common goal. The second case study is concerned with an approach for user activity recognition which serves as baseline for a context-aware adaptive application. Both case studies demonstrate the viability and strengths of the proposed solution and emphasize that the Dempster-Shafer Theory of Evidence should be preferred to pure probability theory in applications involving non-linear Inter-Representation Operations.