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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Laboratory and field trials of the ability of vegetated porous paving to remediate pollutants

Mayer, M. January 2013 (has links)
Flooding is impossible to prevent completely, consequences of excess water can however, be reduced and often avoided via flood risk management. With the increase in impermeable surfaces, approaches that have the intention of imitating natural drainage to manage storm-water are known as Sustainable (Urban) Drainage Systems (SUDS). Pollutants from vehicles have been identified as a concern in the urban environment, with origins including exhaust emissions, engine oil leakage and erosion of vehicle components. Investigation of vegetated parking surfaces (VPS) to limit the impact of pollutants are scarce, therefore this study aims to determine pollution tolerance of grass species for use in VPSs, prior to investigating the effects that vehicles have on a vegetated surfaces and alternative methods in which to analyse them. A pot trial investigated effects of increasing oil concentrations on the growth of four grass species. F. rubra L. was found to tolerate contamination to a higher degree than the other species and L. perenne L. produced more cumulative biomass throughout the investigation. A parallel study determined that Ca, Cu, K, Mg, Mo, P and Zn accumulated in grass shoots, indicating that F. rubra L. and L. perenne L. may be suitable for further analysis. field trial focused on a regularly-used L. perenne L.-covered VPS at a local school, analysing the influence of vehicles on vegetated parking bays. Compaction and mean element concentrations increased across the VPS, with distance from the roadside. Use of mineral magnetism as a proxy for geochemical detection did not prove successful as no significant correlation was identified between magnetic susceptibility (χ) and element concentration. Use of GIS provided this study with an alternative method for data presentation. Usually covering large scale analyses, an interactive geovisual map of geochemical dispersal and compaction across the VPS provided a novel method of visualising results from an investigation of this scale.
142

Sperm activation in Nile tilapia Oreochromis niloticus and the effects of environmentally relevant pollutants on sperm fitness

Musa, Nadirah January 2010 (has links)
In externally fertilizing fishes, multiple factors of the spawning environment may affect the sperm viability, and thus the fertilization rate. In this thesis, the sperm activation effect of osmolality of non-electrolytes and electrolytes activation media, pH and ion channel inhibitors on Nile tilapia, Oreochromis niloticus, and the effect of environmentally relevant pollutants (cadmium, malathion and rotenone) on sperm fitness (motility and morphology) were investigated. Seminal fluid samples collected from male fishes (200-250g) were subjected to activation treatments, then analyzed for sperm motility using motility score, and motility variables using Hobson sperm tracker for straight line velocity (VSL), beat cross frequency (BCF) and percentage of motile cells (MOT). For the ion channel inhibitors and pollutants, the effect on sperm motility variables of VSL, VCL (curvilinear velocity) and LIN (linearity) were determined. Multivariate analysis was also carried out to determine the effects of ion channel inhibitors and pollutants on sperm subpopulations. The effects of pollutants on sperm morphology were observed using microscopy techniques, namely, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Sperm motility was initiated when the sperm were exposed to hypoosmotic electrolytes and non-electrolytes solution. We also found that sperm show optimal activity at pH range of 6-8 which depicts that the effect of pH on sperm motility is negligible. Lanthanum (calcium channel blocker) and flunarizine (sodium-calcium exchanger pump blocker) were found to inhibit sperm motility at 25 and 5 µM, respectively, suggesting that both ion channels play a significant role in sperm activation in O. niloticus. In contrast amiloride, ouabain and quinine showed no effects on activation, indicating that epithelial sodium channels, sodium-potassium ATPase and voltage gated potassium channels respectively are unlikely to have major roles in sperm activation or motility. The spermatozoa of Oreochromis niloticus were uniflagellate with clearly differentiated oval-shaped head, midpiece and flagellum. Sperm exposed to hypoosmotic shock showed swelling of the midpiece and sleeve structure. The pollutants showed dose- and time-dependent effect on sperm motility of the fast linear sperm subpopulation. Sperm morphology was not affected. Sperm motility was inhibited at 0.44, 0.03 and 0.063 µM, cadmium, malathion and rotenone respectively. Both cadmium and malathion exerted effects very quickly after exposure. The effect of cadmium, which can exert toxicity by calcium antagonism, is consistent with the effects of calcium channel blockes and further supports an important role for calcium in sperm activation and motility. Malathion had effects at relatively low, environmentally relevant concentrations, suggesting the presence of functionally important acetylcholinesterase activity in sperm, and also the presence of activation cytochrome P450 activity. Rotenone, a well known mitochondrial poison, affected motility only after 15 min of pretreatment. The alteration of sperm trajectories in fast linear spermatozoa subpopulation by pollutants at submicromolar concentrations as demonstrated in our study implies potentially serious consequences for fish populations in polluted environments. Furthermore the results indicate that fish sperm motility as assessed by CASA could be an ecologically relevant, sensitive, and ethically acceptable method for toxicity testing in environmental risk assessment.
143

Persistent organic pollutants in aquaculture systems in the Pearl River Delta, with focus on their bioaccessibility via fish consumption

Wang, Hongsheng 01 January 2011 (has links)
No description available.
144

Factors influencing the metabolism of inorganic arsenic in humans /

Lindberg, Anna-Lena, January 2007 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.
145

Particularly harmful particles? : a study of airborne particles with a focus on genotoxicity and oxidative stress /

Karlsson, Hanna, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 6 uppsatser.
146

Terrestrial controls on the biogeochemistry of dissolved organic matter and inorganic nitrogen in streams of the central Amazon Basin, Brazil /

McClain, Michael Eugene. January 1996 (has links)
Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [122]-141).
147

Análise da emissão e deposição de poluentes atmosféricos que afetam os ambientes aquáticos pela operação de um centro de distribuição /

Chiuffa, Vinícius Patrocollo Domingos. January 2018 (has links)
Orientador: Maria da Consolação Fonseca de Albuquerque / Resumo: As mudanças nas dinâmicas dos mercados devido aos avanços tecnológicos, a globalização e aumento significativo na gama de produtos ofertados, têm feito com que as empresas revejam seus sistemas logísticos. A fim de atender com maior eficiência seus clientes, a maioria das corporações tem optado pela centralização dos estoques na forma de centros de distribuição (CD). Porém este tipo de operação muitas vezes composta por um grande número de veículos que percorrem grandes distâncias, colaboram para o aumento nos níveis de emissões e deposições de vários poluentes atmosféricos. O objetivo desta pesquisa foi fazer um estudo de caso de um centro de distribuição de uma rede supermercadista, avaliando as emissões atmosféricas e as deposições totais nos corpos d’água da região, para alguns dos poluentes mais comuns liberados na combustão incompleta que ocorre nos motores dos veículos, sendo estes o Dióxido de Carbono (CO2), Hidrocarboneto, Óxidos de Nitrogênio (NOx) e Material Particulado (MP). Também foi proposta uma roteirização, utilizando o algoritmo do vizinho mais próximo, visando diminuir as quilometragens percorridas pela frota, com o objetivo de diminuir os impactos gerados. Os cálculos das emissões para o funcionamento atual do CD, como para a nova rota proposta foram feitas utilizando-se os métodos Top-Down e Bottom-Up, e os cálculos das deposições totais feitas conforme o proposto na literatura. As emissões anuais encontradas atualmente foram de aproximadamente 4.700 tone... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The changes in market dynamics due to technological advances, globalization and a significant increase in the range of products offered, have caused companies to review their logistics systems. In order to serve its customers more efficiently, most corporations have opted to centralize inventories in the form of distribution centers (DCs). However, this type of operation, which is often composed of a large number of vehicles that travel long distances, contribute to the increase in emissions and deposition levels of various atmospheric pollutants. The objective of this research was to make a case study of a distribution center of a supermarket chain, evaluating atmospheric emissions and total depositions in the region's water bodies, for some of the most common pollutants released in the incomplete combustion that occurs in the engines like Carbon Dioxide (CO2), Hydrocarbons (HC), Nitrogen Oxides (NOx) and Particulate Matter (PM). A routing was also proposed, using the algorithm of the nearest neighbor, aiming at reducing the kilometers traveled by the fleet, in order to reduce the impacts generated. The calculations of the emissions for the current operation of the DC, as for the new proposed route were made using the Top-Down and Bottom-Up methods, and the calculations of the total depositions made as proposed in the literature. The annual emissions currently found were approximately 4.700 tons, 193 kg, 10.615 kg and 103 kg for CO2, HC, NOx and PM, respectively. The total d... (Complete abstract click electronic access below) / Mestre
148

Análise da emissão e deposição de poluentes atmosféricos que afetam os ambientes aquáticos pela operação de um centro de distribuição / Analysis of the emission and deposition of atmospheric pollutants that affect the aquatic environments by the operation of a distribution center

Chiuffa, Vinícius Patrocollo Domingos 02 March 2018 (has links)
Submitted by VINICIUS PATROCOLLO DOMINGOS CHIUFFA null (vchiuffa@gmail.com) on 2018-03-26T20:56:05Z No. of bitstreams: 1 Chiuffa_vpd_ilha.pdf: 1416117 bytes, checksum: d72bbe1279d47162e3c77a164c30270c (MD5) / Approved for entry into archive by Cristina Alexandra de Godoy null (cristina@adm.feis.unesp.br) on 2018-03-27T11:40:23Z (GMT) No. of bitstreams: 1 chiuffa_vpd_me_ilha.pdf: 1416117 bytes, checksum: d72bbe1279d47162e3c77a164c30270c (MD5) / Made available in DSpace on 2018-03-27T11:40:23Z (GMT). No. of bitstreams: 1 chiuffa_vpd_me_ilha.pdf: 1416117 bytes, checksum: d72bbe1279d47162e3c77a164c30270c (MD5) Previous issue date: 2018-03-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As mudanças nas dinâmicas dos mercados devido aos avanços tecnológicos, a globalização e aumento significativo na gama de produtos ofertados, têm feito com que as empresas revejam seus sistemas logísticos. A fim de atender com maior eficiência seus clientes, a maioria das corporações tem optado pela centralização dos estoques na forma de centros de distribuição (CD). Porém este tipo de operação muitas vezes composta por um grande número de veículos que percorrem grandes distâncias, colaboram para o aumento nos níveis de emissões e deposições de vários poluentes atmosféricos. O objetivo desta pesquisa foi fazer um estudo de caso de um centro de distribuição de uma rede supermercadista, avaliando as emissões atmosféricas e as deposições totais nos corpos d’água da região, para alguns dos poluentes mais comuns liberados na combustão incompleta que ocorre nos motores dos veículos, sendo estes o Dióxido de Carbono (CO2), Hidrocarboneto, Óxidos de Nitrogênio (NOx) e Material Particulado (MP). Também foi proposta uma roteirização, utilizando o algoritmo do vizinho mais próximo, visando diminuir as quilometragens percorridas pela frota, com o objetivo de diminuir os impactos gerados. Os cálculos das emissões para o funcionamento atual do CD, como para a nova rota proposta foram feitas utilizando-se os métodos Top-Down e Bottom-Up, e os cálculos das deposições totais feitas conforme o proposto na literatura. As emissões anuais encontradas atualmente foram de aproximadamente 4.700 toneladas, 193 kg, 10.615 kg e 103 kg para o CO2, HC, NOx e MP, respectivamente. Já as deposições totais nos corpos d’água de 4,74 kg de HC, 1.777 de NOx, 9,0 kg de MP10 e 4,0 kg de MP2.5. As emissões anuais encontradas após a roteirização foram de aproximadamente 1.310 toneladas, 53 kg, 2.957 kg e 29 kg para o CO2, HC, NOx e MP, respectivamente, e as deposições totais nos corpos d’água de 1,32 kg de HC, 328 kg de NOx, 2,50 kg de MP10 e 1,10 kg de MP2.5. Portanto, com a roteirização simulada foi possível uma redução nas emissões e nas deposições por volta de 72%, podendo-se concluir que maiores devem ser as atenções dadas a esse tipo de operação para minimizar os impactos negativos tanto à saúde da população quanto ao meio ambiente. / The changes in market dynamics due to technological advances, globalization and a significant increase in the range of products offered, have caused companies to review their logistics systems. In order to serve its customers more efficiently, most corporations have opted to centralize inventories in the form of distribution centers (DCs). However, this type of operation, which is often composed of a large number of vehicles that travel long distances, contribute to the increase in emissions and deposition levels of various atmospheric pollutants. The objective of this research was to make a case study of a distribution center of a supermarket chain, evaluating atmospheric emissions and total depositions in the region's water bodies, for some of the most common pollutants released in the incomplete combustion that occurs in the engines like Carbon Dioxide (CO2), Hydrocarbons (HC), Nitrogen Oxides (NOx) and Particulate Matter (PM). A routing was also proposed, using the algorithm of the nearest neighbor, aiming at reducing the kilometers traveled by the fleet, in order to reduce the impacts generated. The calculations of the emissions for the current operation of the DC, as for the new proposed route were made using the Top-Down and Bottom-Up methods, and the calculations of the total depositions made as proposed in the literature. The annual emissions currently found were approximately 4.700 tons, 193 kg, 10.615 kg and 103 kg for CO2, HC, NOx and PM, respectively. The total deposition in the bodies of water of 4,74 kg of HC, 1.777 kg of NOx, 9,0 kg of PM10 and 4,0 kg of PM2.5. The annual emissions found after routing were approximately 1.310 tons, 53 kg, 2.957 kg and 29 kg for CO2, HC, NOx and PM, respectively, and the total depositions in water bodies of 1,32 kg of HC, 328 kg of NOx, 2,50 kg of PM10 and 1,10 kg of PM2.5. Therefore, with simulated routing, it was possible to reduce emissions and depositions by 72%, and it can be concluded that greater attention should be given to this type of operation to minimize negative impacts on both the population's health and the environment.
149

Phenolic compounds in water and the implications for rapid detection of indicator micro-organisms using ß-D-Galactosidase and ß-D-Glucuronidase

Abboo, Sagaran January 2009 (has links)
Faecal contamination in water is detected using appropriate microbial models such as total coliforms, faecal coliforms and E. coli. Βeta-D-Galactosidase (β-GAL) and Beta-D-glucuronidase (β-GUD) are two marker enzymes that are used to test for the presence of total coliforms and E. coli in water samples, respectively. Various assay methods have been developed using chromogenic and fluorogenic substrates. In this study, the chromogenic substrates chlorophenol red β-D-galactopyranoside (CPRG) for β-GAL and p-nitrophenyl-β-D-galactopyranoside (PNPG) for β-GUD were used. Potential problems associated with this approach include interference from other organisms present in the environment (e.g. plants, algae and other bacteria), as well as the presence of certain chemicals, such as phenolic compounds in water. Phenolic compounds are present in the aquatic environment due to their extensive industrial applications. The USA Enviromental Protection Agency (EPA) lists 11 Priority Pollutant Phenols (PPP) due to their high level of toxicity. This study investigated the interfering effects of the eleven PPP found in water on the enzyme activities of both the β-GAL and β-GUD enzyme assays. The presence of these PPP in the β-GAL and β-GUD enzyme assays showed that over and underestimation of activity may occur due to inhibition or activation of these enzymes. Three types of inhibition to enzyme activities were identified from double reciprocal Lineweaver-Burk plots. The inhibition constants (Ki) were determined for all inhibitory phenolic compounds from appropriate secondary plots. Furthermore, this study presented a validated reverse phase high performance liquid chromatography (RP-HPLC) method, developed for the simultaneous detection, separation and determination of all eleven phenolic compounds found in the environment. This method demonstrated good linearity, reproducibility, accuracy and sensitivity. Environmental water samples were collected from rivers, streams, industrial sites and wastewater treatment plant effluent. These samples were extracted and concentrated using a solid phase extraction (SPE) procedure prior to analysis employing the newly developed HPLC method in this study. Seasonal variations on the presence of the PPP in the environment were observed at certain collection sites. The concentrations found were between 0.033 μg/ml for 2,4-dinitrophenol in a running stream to 0.890 mg/ml for pentachlorophenol from an tannery industrial site. These concentrations of phenolic compounds found in these environments were able to interfere with the β-GAL and β-GUD enzyme assays.
150

Risk assessment of perfluorinated compound (PFC) contamination and their effects on animal reproductive health

Zhao, Yinge 01 January 2012 (has links)
No description available.

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