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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.
1

A Rapid Assessment Method Examining the Ecological Health of Tidal Marine Wetlands in Galveston Bay, Texas

Staszak, Lindsey Ann 2010 August 1900 (has links)
Wetlands are one of the most productive ecosystems in the world, housing diverse biota and serving important functions as nursery habitat and feeding grounds. However, nearly 70% of coastal wetlands, including 21% of the salt marshes in Texas, have been lost since 1950, due primarily to coastal development and declines in water quality. Restoration of wetlands is essential to reestablish lost functions, but there is no standard method to assess the ecological health of restored salt marshes in Texas. Numerous recent salt marsh restoration projects in Galveston Bay have made it an ideal model system to develop and implement an ecosystem health assessment, known as a rapid assessment method (RAM). In this study, I modified an established RAM, the Mid-Atlantic Tidal Fringe Assessment, to compare the ecological health of representative reference salt marshes to restored marshes around Galveston Bay. I measured 14 biotic and abiotic characteristics at 12 restored and 6 reference sites around Galveston Bay, and then grouped those measurements into four functional groups: landscape/site characteristics, hydrology, wildlife habitat, and soil characteristics. I then developed a scoring system (minimum 0, maximum 100) to summarize the overall health of each site. Most of the restored salt marshes in this study scored lower than reference marshes. The average reference site score was 81.8 and the average restored site score was 69.7. Functional group values for landscape/site characteristics, soil, and wildlife habitat were significantly lower in restored than in reference sites. In particular, restored sites had more hydrological modifications, more fill material, and fewer macrobenthos than reference wetlands. The Galv-RAM effectively and efficiently identified restoration successes and weaknesses. With this information, management agencies can address restoration shortcomings by adapting management goals. The Galv-RAM will streamline monitoring protocols and facilitate long-term examination of restored wetland health. As a result, management decisions can be modified based on the scores received in different categories or variables to improve and or meet the goals of the project.
2

Introduction: Systematic data of tungiasis epidemiology are still scarce in endemic areas / Um novo mÃtodo para avaliaÃÃo rÃpida da tungÃase em Ãreas endÃmicas

Liana de Moura Ariza 18 November 2009 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / IntroduÃÃo: Existe pouco conhecimento sistemÃtico sobre a epidemiologia da tungÃase em Ãreas endÃmicas. SÃo necessÃrios mÃtodos de avaliaÃÃo rÃpida para delimitar Ãreas em risco e possibilitar a implementaÃÃo e avaliaÃÃo do impacto de intervenÃÃes. Objetivo: Desenvolver e avaliar um mÃtodo epidemiolÃgico rÃpido para estimar a prevalÃncia geral e a gravidade da tungÃase em comunidades endÃmicas com diferentes caracterÃsticas demogrÃficas, sÃcio-culturais e ambientais. Material e MÃtodos: AnÃlise de dez estudos transversais realizados em cinco comunidades, trÃs do Brasil (dados secundÃrios) e duas da NigÃria (dados primÃrios), no perÃodo de 2001-2008. A tungÃase foi diagnosticada clinicamente a partir da presenÃa de lesÃes de Tunga penetrans na epiderme dos indivÃduos. Para elaborar o mÃtodo rÃpido, seis localizaÃÃes topogrÃficas dos pÃs foram selecionadas como potenciais indicadores de infestaÃÃo em nÃvel comunitÃrio. Foram feitas regressÃes lineares, calculados coeficientes de determinaÃÃo (R2) e os valores p. CritÃrios operacionais como rapidez e facilidade do exame tambÃm foram utilizados para a escolha do mÃtodo mais adequado. Resultados: Ao todo, nos dez estudos transversais foram incluÃdos 7.121 indivÃduos. As prevalÃncias da tungÃase variaram entre 21% e 54%. Nas duas comunidades nigerianas a prevalÃncia geral da tungÃase nas 302 pessoas examinadas foi 47% (intervalo de confianÃa 95%: 41%-53%). Os homens foram mais infestados do que as mulheres (51% vs. 44%, p=0,2), assim como as crianÃas em comparaÃÃo aos indivÃduos >15 anos (60% vs. 33%, p<0,0001). Na anÃlise dos potencias mÃtodos rÃpidos, os coeficientes de determinaÃÃo foram altos, variaram entre 70% e 96% para as seis localizaÃÃes topogrÃficas, com valores p significantes (todos <0,002). A prevalÃncia na area periungueal dos pÃs apresentou o mais alto coeficiente de determinaÃÃo (96%), alÃm da maior rapidez e facilidade do exame. As prevalÃncias gerais estimadas a partir da equaÃÃo da reta Y= 1,12 x prevalÃncia na Ãrea periungueal + 5,0 apresentaram mÃdia do erro absoluto de 1,9%. PrevalÃncias graves (> 20 lesÃes), estimadas pela equaÃÃo da reta Y= 0,24 x prevalÃncia na Ãrea periungueal - 3,4, apresentaram erro absoluto mÃdio de 0,9%. ConclusÃo: A tungÃase à um problema de saÃde pÃblica em comunidades pesqueiras na NigÃria. A identificaÃÃo de T. penetrans na Ãrea periungueal dos pÃs pode ser usada como mÃtodo rÃpido e confiÃvel de avaliaÃÃo epidemiolÃgica. Sua aplicaÃÃo auxiliarà na delimitaÃÃo de Ãreas endÃmicas, bem como no planejamento de medidas que visem à reduÃÃo da tungÃase em Ãreas endÃmicas. . / . Rapid assessment methods are needed to delimitation of risk communities and to enable implementation and evaluation of impact interventions. Objective: To develop and assess a rapid epidemiologic method to estimate the overall prevalence of tungiasis and severity of disease in endemic communities with distinct demographic, socio-cultural and environment characteristics. Material and Methods: Analysis data from ten population-based surveys on tungiasis, performed in five endemic communities â three in Brazil (secondary data) and two Nigeria (primary data) â between 2001 and 2008. In all surveys, tungiasis was clinically diagnostic by presence of Tunga penetrans into epidermis of participants. To elaborate rapid assessment method six topographic sites of the feet were selected as potential infestation indicator in community level. Linear regression analyses were performed as well strength of associations (R2) and p values were calculated. Estimated prevalences were calculated for each of the ten surveys and compared to true prevalences. The most useful topographic localization to define a rapid assessment method was select based on the strength of association and operational aspects. Result: In total, 7121 individuals of the five communities were examined. Prevalence of tungiasis varied between 21.1% and 54.4%. In the two Nigerian communities the combined overall prevalence was 47% (142/302; 95% confidente intervale: 41%-53%). Tungiasis were more common in males than in females (51,5% vs. 46,3%; p=0,2). Children prevalence (<14 years) was statistically higher then adolescents and adults prevalence (60% vs. 33%, p<0,0001). In the ten surveys, all strength coefficients were high for the six localizations (ranged between 70% and 96%) and p values were significant (all <0,002). The presence of periungual lesions on the toes showed the highest strength coefficient (R2=96%; P<0.0001) and it was identified as the most useful and rapid localization to estimate the prevalence of tungiasis. Estimating prevalence of tungiasis by equation [estimated prevalence] = 1,12 x [prevalence on periungual sites] + 5,0), the mean absolute error was 1,9%. Tungiasis on this topographic site also reliably estimated prevalence of severe disease (>20 lesions) using the equation [estimated prevalence] = 0,24 x [prevalence on periungual sites] â 3,4); mean absolute error was 0,9%. Conslusion: Tungiasis is a public health problem in the fishing communities in Nigeria. Identification of T. penetrans in the periungual area of the feet can be used as a rapid and reliable method to assess the epidemiological situation of endemic areas. This approach will help to delimit endemic communities and to plan control measures aimed at the reduction of tungiasis. Key-words: Tungiasis; Tunga penetrans; Epidemiology; Rapid assessment method; Public Health; Africa; Brazil

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