• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 6
  • 6
  • 1
  • 1
  • 1
  • Tagged with
  • 17
  • 17
  • 8
  • 7
  • 5
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 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.
1

Low molecular weight halocarbons in seawater

Nightingale, Philip D. January 1991 (has links)
No description available.
2

The determination and environmental significance of planar aromatic compounds in the marine environment

Hess, Philipp January 1998 (has links)
No description available.
3

Improvement of a three-tier wireless sensor network for environment monitoring

Wang, Xu January 1900 (has links)
Doctor of Philosophy / Department of Biological & Agricultural Engineering / Naiqian Zhang / A three-tier wireless sensor network (WSN) was developed and deployed to remotely monitor suspended sediment concentration and stream velocity in real-time. Two years of field experiments have demonstrated the achievement of such capabilities. But several weak points emerged and required essential performance improvement and additional research on the radio propagation mechanism within the original three-tier WSN. In the original three-tier WSN, long time delay, potential data loss, and limited network throughput all restricted the network transmission performance. Upon the above issues, the transmission delay was reduced through shortening the raw data storage buffer and the data packet length; the data loss rate was decreased by adopting a mechanism using semaphores and adding feedback after data transmission; the network throughput was enlarged through the event- and time-driven scheduling method. In order to find a long-range wireless transmission method as an alternative to the commercial cellular service used in the original WSN, a central station using meteor burst communication (MBC) technology was developed and deployed. During an 8-month field test, it was capable of performing long distance communication with a low data loss rate and transmission error rate. But due to unstable availability of the meteor trails, the MBC network throughput was constrained. To reduce in-situ maintenance, over-the-air programming was implemented. Thus, programs running in the central station and the gateway station can be updated remotely. To investigate the radio propagation in densely vegetative areas, a 2.4 GHz radio propagation path loss model was derived to predict the short-range path loss from the path loss in the open area and the path loss due to dense vegetation. In addition, field experiments demonstrated that ambient air temperature, relative humidity, and heavy rainfall could also affect wireless signal strength.
4

Metabolic enzymes and mixed-function oxygenase (MFO) system in pink snapper (Pagrus auratus): biochemical and histological relationships

Tugiyono, January 2001 (has links)
The environmental health of aquatic ecosystems depends amongst others, on the chemical pollution coming from activities in the catchment's area. In the Swan River Estuary, Western Australia, the chemical pollutants of concern released into the river are petroleum hydrocarbons and sodium pentachlorophenate (NaPCP). Decreased water quality causes a loss of biotic diversity especially amongst fish populations. The health of aquatic ecosystems can be monitored by fish health, especially fish located at higher levels in the food chain. Pink snapper (Pagrus auratus), an endemic Western Australian fish species, was tested for its potential as a bioindicator of aquatic environmental health. This thesis presents data on the responsiveness of pink snapper to the contaminants of concern, using biomarkers such as serum sorbitol dehydrogenase (SDH), mixed function oxygenase (MFO), metabolic enzymes such as citrate synthase (CS), cytochrome C oxidase (CCO) and lactate dehydrogenase (LDH) and the histological alteration such as hepatic cell lesions (hyperplasia and hypertrophy), and glycogen and lipid droplets. The metabolic enzymes CCO and LDH as well as the hepatic MFO induction and histopathology were proven to be the most suitable biomarkers for use for routine monitoring of the Swan River Estuary using pink snapper as a bioindicator. However, CS activity and hepatic cell lesions (hyperplasia and hypertrophy) did not respond to exposure to contamination and are therefore not suited as biomarkers of effects in pink snapper. The first phase of the study aimed at investigating the responsiveness of juvenile pink snapper to an MFO inducer. Polychlorinated biphenyl isomer # 126 was selected as a model MFO inducer for this study. In the initial experiment, MFO activity was measured as a biomarker of exposure, and serum SDH activity was assessed as a biomarker of liver damage. / MFO and SDH activities were of special interest as these biochemical tools have not previously been validated for any Western Australia fish species. Juvenile pink snapper were injected intraperitoneally (i.p.) with 0, 10, 100, 500, 1000 microgram PCB-126 per kilogram. Fish were sacrificed 10 days postinjection, and liver and blood were collected for MFO and SDH analysis, respectively. Doses of 10 and 100 microgram PCB-126 per kilogram caused the highest MFO induction, while doses of 0 and 1000 microgram PCB-126 per kilogram did not result in higher MFO activity relative to carrier-injected (peanut oil) control fish. SDH activities were not significantly different among treatments indicating that hepatocellular damage was not responsible for the reduced MFO activity at the highest dose. Metabolic enzymes in pink snapper exposed by NaPCP were studied in the second phase of the experiment. The aim of this second experiment was to test the responsiveness of pink snapper to contaminants known to cause metabolic perturbations in vertebrates. Juvenile pink snapper were intraperitoneally (i.p.) injected with 0, 5, 10, 20 mg per kilogram. Oxidative enzymes were assessed by measuring CS and CCO activities and glycolytic enzyme was assessed by measuring LDI-1 activity in liver and white muscle tissues. CS activity remained unchanged in both the white muscle and in the liver. CCO activity was significantly enhanced in liver in all treated fish relative to control fish, but not in the white muscle. LDH activity was also higher in liver in all treated fish as compared to control fish, while in white muscle, LDH activity significantly increased at the highest dose injected. / The use of a suite of biochemical markers is useful in determining the effects of xenobiotic exposure of aquatic organisms, because it provides a holistic approach with biomarkers at different levels of biological organization. For the third and final phase of the study the suite of biomarkers selected were MFO, metabolic enzyme (CS, CCO and LDH) activities, and histological alternations in combination with physiological indices. The aim of this last experiment was to investigate if a modified liver metabolic activity would alter the MFO induction potential. To test if altered liver metabolism would influence liver detoxication capacities, juvenile pink snapper were i.p. injected with peanut oil (control), or pentachlorobiphenyl # 126 (PCB 126), with sodium pentachlorophenate (NaPCP), or combination of PCB 126+NaPCP. Relative to controls, ethoxyresorufin-O-deethylase (EROD) activity was induced in the PCB 126 and PCB 126+NaPCP fish, but not in the NaPCP group. In the liver, CCO activity was enhanced by the treatments while CS activity remained unchanged and LDH activity was increased in the NaPCP treatment only. In the white muscle, only the PCB 126+ NaPCP treatment enhanced CCO activity, with all other enzymatic activities remaining unchanged. Low serum sorbitol dehydrogenase (sSDH) activity and histopathology of the liver indicated no significant alteration of cellular structure, albeit the lipid droplet size was increased in the PCB 126 and in the PCB 126+NaPCP treatments. / It is concluded that the hepatic metabolic changes correspond to histopathological observations, but an altered metabolic capacity does not influence the metabolism of xenobiotics by liver enzymes, as measured by EROD activity. These experiments answered the need to identify a suitable fish species for routine monitoring of the aquatic environment in Western Australia. It also identified the most suitable biochemical markers of exposure and effects, and the suitability of the pink snapper as a bioindicator. Finally, the experiments investigated interactions between biomarkers and provided new knowledge useful to scientists using MFO and/or metabolic enzymes in field or laboratory toxicology.
5

Monitoramento do ambiente organizacional em pequenas empresas: estudo de casos no setores metal-mecânico e base tecnológica / Scanning of the organizational environment in small business: multiple case study of metal-mechanic industries and small technology-based companies

Musetti, Tiago Fernando 19 August 2015 (has links)
Esta dissertação tem como principal objetivo analisar o processo monitoramento ambiental em empresas de pequeno porte. No atual cenário competitivo, cada vez mais volátil e incerto, em que as fronteiras mercadológicas se alteram com grande rapidez é fundamental que se conheça e monitore o ambiente competitivo em que uma organização está inserida como forma de reduzir o grau de incerteza e garantir a sua sobrevivência no longo prazo. Entende-se por monitoramento ambiental o processo de transformar os dados obtidos no ambiente organizacional em informações estratégicas para ajudar o dirigente na tomada de decisão. O método de pesquisa utilizado nesta dissertação foi estudo de casos em que foram entrevistados quatro dirigentes de empresas de pequeno porte, sendo dois empresários do setor metal-mecânico e dois empresários do setor de base tecnológica. Os dados foram coletados por meio de entrevistas semi-estruturadas e analisados pela técnica de Análise de Conteúdo. Como resultado obteve-se que as principais variáveis do ambiente geral são a econômica e a político-legal, enquanto que as principais variáveis do ambiente específico são os concorrentes e os clientes e produtos substitutos. As fontes de informação mais utilizadas pelos dirigentes são a opinião dos clientes e os encontros com outros empresários. A contribuição da pesquisa é demonstrar as principais variáveis e subvariáveis ambientais, assim como as fontes de informações que os dirigentes podem utilizar para monitorar, mesmo que informalmente, o ambiental organizacional. / The objective of this work is to analyse the environmental monitoring process in small enterprises. In the current competitive scene, more and more volatile and uncertain, in which market frontiers are altered very quickly, it is fundamental to know and monitor the competitive environment into which an enterprise is put, as a way to reduce the uncertainty and guarantee its long term survival. Environmental monitoring is the process of transforming data obtained in the organizational environment in strategic information in order to help the manager make a decision. The research method used in this work was the study case, in which four managers were interviewed; among them, two managers from the metal-mechanic and two managers from the technological base sector. The data was collected through semi-structured interviews and analysed through the Content Analysis technique. As a result, the main variables of the general environment are the economic and the legal-political ones, while the main variables in the specific environment are the competition and the clients and the substitute products. The most used information sources used by the managers are the opinion of the clients and the meetings with other managers. The contribution of this research is to demonstrate the main variables and environmental sub-variables, as well as the information sources which may be used by the managers to monitor, even informally, the organization environment.
6

Monitoramento do ambiente organizacional em pequenas empresas: estudo de casos no setores metal-mecânico e base tecnológica / Scanning of the organizational environment in small business: multiple case study of metal-mechanic industries and small technology-based companies

Tiago Fernando Musetti 19 August 2015 (has links)
Esta dissertação tem como principal objetivo analisar o processo monitoramento ambiental em empresas de pequeno porte. No atual cenário competitivo, cada vez mais volátil e incerto, em que as fronteiras mercadológicas se alteram com grande rapidez é fundamental que se conheça e monitore o ambiente competitivo em que uma organização está inserida como forma de reduzir o grau de incerteza e garantir a sua sobrevivência no longo prazo. Entende-se por monitoramento ambiental o processo de transformar os dados obtidos no ambiente organizacional em informações estratégicas para ajudar o dirigente na tomada de decisão. O método de pesquisa utilizado nesta dissertação foi estudo de casos em que foram entrevistados quatro dirigentes de empresas de pequeno porte, sendo dois empresários do setor metal-mecânico e dois empresários do setor de base tecnológica. Os dados foram coletados por meio de entrevistas semi-estruturadas e analisados pela técnica de Análise de Conteúdo. Como resultado obteve-se que as principais variáveis do ambiente geral são a econômica e a político-legal, enquanto que as principais variáveis do ambiente específico são os concorrentes e os clientes e produtos substitutos. As fontes de informação mais utilizadas pelos dirigentes são a opinião dos clientes e os encontros com outros empresários. A contribuição da pesquisa é demonstrar as principais variáveis e subvariáveis ambientais, assim como as fontes de informações que os dirigentes podem utilizar para monitorar, mesmo que informalmente, o ambiental organizacional. / The objective of this work is to analyse the environmental monitoring process in small enterprises. In the current competitive scene, more and more volatile and uncertain, in which market frontiers are altered very quickly, it is fundamental to know and monitor the competitive environment into which an enterprise is put, as a way to reduce the uncertainty and guarantee its long term survival. Environmental monitoring is the process of transforming data obtained in the organizational environment in strategic information in order to help the manager make a decision. The research method used in this work was the study case, in which four managers were interviewed; among them, two managers from the metal-mechanic and two managers from the technological base sector. The data was collected through semi-structured interviews and analysed through the Content Analysis technique. As a result, the main variables of the general environment are the economic and the legal-political ones, while the main variables in the specific environment are the competition and the clients and the substitute products. The most used information sources used by the managers are the opinion of the clients and the meetings with other managers. The contribution of this research is to demonstrate the main variables and environmental sub-variables, as well as the information sources which may be used by the managers to monitor, even informally, the organization environment.
7

Indoor dust as a matrix for surveillance of COVID-19 outbreaks

Renninger, Nicole 04 October 2021 (has links)
No description available.
8

Padrão de atividades, comportamento alimentar, exploração de habitat e área de vida de um grupo de Sapajus flavius (Schreber, 1774) (Primates, Cebidae) em um fragmento de floresta atlântica, Paraíba, Brasil

Rodrigues, Keoma Coutinho 15 March 2013 (has links)
Submitted by Carlos Augusto Rolim da Silva Junior (carlos_jrolim@hotmail.com) on 2015-11-23T14:00:01Z No. of bitstreams: 1 arquivototal.pdf: 1655565 bytes, checksum: a448ab517468ffef5d4d3427d26c42d4 (MD5) / Made available in DSpace on 2015-11-23T14:00:01Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1655565 bytes, checksum: a448ab517468ffef5d4d3427d26c42d4 (MD5) Previous issue date: 2013-03-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The blonde capuchin monkey, Sapajus flavius , occurs in remnants of Atlantic Forest in Brazil north of the São Francisco River, and is included in the IUCN red list as "Critically Endangered". Studies of the behavior and eating habits, exploitation and habitat the pattern of use of space are important, since there is a gap of information to species. Such information will assess how populations of S. flavius are living in forest fragments, enabling the deployment of more effective conservation actions. The study objectives were to describe the activity budgets, feeding behavior, the size of the home range and habitat exploitation pattern of a group of blonde capuchin monkey in RPPN Engenho Gargaú located in the municipality of Santa Rita (Paraíba). Data were collected by scan sampling method with instant records every 5 minutes. Phenological data were collected monthly from 90 vegetables fruiting specimens whose intensity were calculated using the Activity Index. The Scan Sampling was dominated by the travel (38.96%), followed by feed (28.58%), forage (21.66%), rest (4.77%), agonistic behavior, social, vocalization and drinking water (6%). This pattern varied significantly during the dry and rainy season. The food was more frequent in the dry season and the displacement in rainy season. The diet group was composed of fruit (43%), stalks of sugar cane (30%), prey animals (15%), leaves (7%), plant parts, including sheath, petiole, bark (3%) and flowers (2%). In the rainy season, fruit consumption was significantly higher and was positively correlated with the intensity of fruiting. The consumption of sugar cane was higher in the dry season, when fruit production was low. 48 plant species were identified in the diet, being Saccharam sp. (37.83%), Elaeis spp. (16.99%) and Tapirira guianenses (6.22%) the most important. The home-range calculated by the Minimum Convex Polygon (MPC) for the group was of 240.22 hectares. The habitats more explored were in Regeneration Forest (35.5%), Edge of Forest in Regeneration (28.2%), Edge of Flooded Mature Forest (17.5%), Edge of mature forest (9.6%) and mature forest (9.2%). The pattern of activities, diet and living area were consistent to those found for the genus Sapajus and all aspects were influenced by the seasonality of food resources and the intervening matrix composed predominantly of sugar cane. / O macaco-prego-galego, Sapajus flavius, ocorre em remanescentes de Mata Atlântica ao norte do rio São Francisco, sendo incluída na lista de espécies ameaçadas pela IUCN como “Criticamente em perigo”. Estudos referentes aos comportamentos e hábitos alimentares, à exploração de hábitats e ao padrão de uso do espaço são importantes, uma vez que há uma lacuna de informações para espécie. Tais informações permitirão avaliar como as populações de S. flavius estão vivendo nos fragmentos florestais, possibilitando a implantação de ações conservacionistas mais eficazes. Os objetivos do estudo foram descrever o padrão de atividades, o comportamento alimentar, o tamanho da área de vida e o padrão de exploração de hábitats de um grupo de macaco-pregogalego na RPPN Engenho Gargaú localizada no município de Santa Rita/PB. Os dados foram coletados pelo método de varredura instantânea com registros a cada 5 minutos. Foram coletados dados fenológicos mensais de 90 espécimes vegetais, cuja intensidade de frutificação foi calculada pelo método de Índice de Atividade. O padrão de atividades foi dominado pelo deslocamento (38,96%), seguido de alimentação (28,58%), forrageio (21,66%), descanso (4,77%), comportamentos agonísticos, sociais, de vocalização e de beber água (6%). Tal padrão variou significativamente nos períodos seco e chuvoso. A alimentação foi mais frequente no período seco e o deslocamento no período chuvoso. A dieta do grupo foi composta por frutos (43%), colmos de cana-de-açúcar (30%), presas animais (15%), folhas (7%), partes vegetais, incluindo bainha, pecíolo, cascas de árvores (3%) e flores (2%). No período chuvoso, o consumo de frutos foi significativamente maior e esteve positivamente correlacionado com a intensidade de frutificação. O consumo de colmos foi maior no período seco, quando a produção de frutos foi baixa. Foram identificadas 48 espécies vegetais incluídas na dieta, sendo Saccharam spp. (37,83%), Elaeis spp. (16.99%) e Tapirira guianenses (6,22%) as mais importantes. Área de vida calculada pelo método do Mínimo Polígono Convexo (MPC) para o grupo foi de 240.22 hectares. Os habitats mais explorados foram Floresta em Regeneração (35.5%), Borda de Floresta em Regeneração (28.2%), Borda de Floresta Madura Alagada (17.5%), Borda de Floresta Madura (9.6%) e Floresta Madura (9.2%). O padrão de atividades, dieta e área de vida foram compatíveis aos encontrados para o gênero Sapajus e todos os aspectos foram influenciados pela sazonalidade dos recursos alimentares e pela matriz interveniente formada predominantemente por cana-de-açúcar.
9

A Comparative Study Of Environmental Health Risks In Two Urban Poor Settlements Using Novel Field-Based Geospatial Approaches

Bempah, Sandra Owusuaah 13 April 2022 (has links)
No description available.
10

Valores de referência de metais pesados em solos de Mato Grosso e Rondônia / Reference Values for heavy metals in soils from Mato Grosso and Rondônia states, Brazil

Santos, Sabrina Novaes dos 10 June 2011 (has links)
Os órgãos de monitoramento ambiental necessitam de indicadores de referência para a avaliação continuada dos impactos ambientais. Indicadores são obtidos por meio da comparação dos teores totais de elementos tóxicos de um solo com valores determinados em condições naturais (não poluídos) ou com valores de referência. No Brasil, com a crescente demanda social pela melhoria e manutenção da qualidade ambiental, alguns estudos foram realizados com o objetivo de estabelecer valores orientadores para metais pesados em solos. Estes são valores préestabelecidos quanto à presença de substâncias químicas que possibilitam a verificação de possível contaminação. A legislação brasileira estabelece três valores orientadores: Valores de Referência de Qualidade (VRQs), de Prevenção (VP) e de Investigação (VI). O VRQ indica o limite de qualidade para um solo considerado limpo a ser utilizado em ações de prevenção da poluição do solo e no controle de áreas contaminadas. Foram coletadas amostras de solo dos estados de Mato Grosso e Rondônia, nas profundidades de 0-5, 5-10, 10-20 e 20-30 cm, em áreas de vegetação nativa (sem ou mínima intervenção antrópica). Objetivou-se com essa dissertação: (i) determinar os valores de referência de metais pesados em solos de Mato Grosso e Rondônia; (ii) avaliar métodos de extração de teores pseudototais de metais pesados (EPA 3051 e Água Régia); (iii) correlacionar estes valores com atributos físicos e químicos dos solos; (iv) correlacionar os resultados desse estudo com valores já estabelecidos para solos de outros estados brasileiros. Partiu-se das hipóteses: i) não ocorrerão diferenças entre os teores naturais de metais pesados nos solos de Mato Grosso e Rondônia pelos dois métodos de extração de teores pseudototais de metais; ii) os VRQ de metais pesados para os solos de Mato Grosso e Rondônia são diferentes dos VRQ obtidos para solos de outros estados brasileiros; e iii) haverá correlação significativa entre os teores naturais de metais pesados e os atributos físicos e químicos dos solos. Houve diferença entre os métodos da água régia e EPA 3051 para recuperação dos metais Co, Ni, Pb e Zn, sendo a água régia o método que mais extraiu esses elementos, enquanto os teores de Cr e de Cu não diferiram entre os métodos. A água régia, em geral, apresentou maiores recuperações dos teores pseudototais de metais pesados nos solos. Os teores dos óxidos de Fe e Mn foram as variáveis que, de forma geral, mais correlacionaram com os metais pesados. O teor de carbono orgânico não contribuiu para avaliação da variação geral dos teores de metais por não correlacionar significativamente com nenhuma variável. As variações encontradas entre os teores de metais pesados dos solos do mundo e de outros estados brasileiros reafirma a necessidade da obtenção de valores de referência para cada estado ou para cada tipo de solo, dependendo da variação das características geomorfológicas, pedológicas e geológicas do estado. / Environmental monitoring institutions need benchmarks for continuous assessment of environmental impacts. Indicators are obtained by comparing the total levels of toxic elements in soils with values determined in natural conditions (unpolluted) or with reference values. Because of the growing social demand for improvement and maintenance of environmental quality in Brazil, some studies have been carried out to establish guideline values for heavy metals in soils. These are pre-set values for the presence of chemicals that enable the verification of possible contamination. The Brazilian National Environmental Agency establishes three guideline values: Reference Value (RV); Prevention Value and Intervention Value. The RV indicates the quality threshold for a considered clean soil to be used in actions to prevent pollution of soil and control of contaminated areas. Soil samples were collected from the states of Mato Grosso and Rondônia, Brazil, at 0-5, 5-10, 10-20 and 20-30 cm layers, in areas of native vegetation (no or minimal human intervention). The objectives of this thesis were: (i) to determine the reference values of heavy metals in soils of Mato Grosso and Rondonia, (ii) to evaluate extraction methods for pseudototais levels of heavy metals (EPA 3051 and aqua regia), (iii) to correlate these values with physical and chemical soils attributes, and (iv) to correlate the results of this study with values established for soils from other Brazilian states. It started from following assumptions: i) no differences will be observed between the natural contents of heavy metals in soils of Mato Grosso and Rondônia by the two extraction methods, ii) the RV of heavy metals for Mato Grosso and Rondônia soils are different from RV obtained for soils from other Brazilian states, and iii) there are significant correlations between natural levels of heavy metals and the physical and chemical attributes of soils. Differences between aqua regia and EPA 3051 were found for Co, Ni, Pb and Zn, the aqua regia method extracting a higher amount of these elements, while the levels of Cr and Cu did not differ between the methods. The aqua regia, in general, had a better recovery of the pseudototal levels of heavy metals in the soils. Contents of Fe and Mn oxides were the variables that, in general, more correlated with the contents of heavy metals in the soils. The organic carbon content did not contribute to assessment of the overall variation of the metal levels because it did not correlate significantly for any variable. Differences between the levels of heavy metals in soils of the world and from other Brazilian states reaffirm the necessity of obtaining reference values for each state or each type of soil, depending on the variation of geomorphological, pedological and geological features of the state.

Page generated in 0.1516 seconds