Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 85-95).

Orientador: Marcelo Antonio Amaro Pinheiro / Resumo: Na região Amazônica muitas áreas de manguezal ainda se encontram conservadas. Entretanto, atividades antrópicas de degradação e contaminação, especialmente por metais, começam a alcançar escalas preocupantes, podendo afetar esse ecossistema e seus recursos. O objetivo do presente estudo foi avaliar a contaminação e bioacumulação de metais (Cu, Cd, Cr, Pb e Mn) pelo caranguejo-uçá (Ucides cordatus) e o risco potencial para a saúde humana pela ingestão desse crustáceo, considerado um recurso pesqueiro de grande importância na região amazônica. Amostras de espécimes de U. cordatus, água, sedimento, e folhas de Rhizophora mangle foram coletadas em áreas de manguezais, sendo uma conservada e outra antropizada para ambos os estados do Pará e Maranhão. As concentrações metálicas nas amostras bióticas e abióticas foram quantificadas por Espectrometria de Emissão Óptica por Plasma Acoplado Indutivamente (ICP-OES), com posterior estimativa do Fator de Bioacumulação e de análises multinível para os metais avaliados. Para avaliação do risco de consumo humano foram estimados o consumo diário (EDI), o quociente de risco (THQ) e o número de refeições elegíveis por mês (CRmm). As concentrações de metais no sedimento estavam abaixo dos níveis estabelecidos pela legislação, diferindo do observado para as amostras de água, onde Cu, Mn e Pb, cujos valores estavam acima dos limites estabelecidos para águas estuarinas. Mesmo sendo em sua maioria de origem natural, observou-se que esses elementos e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the Amazon region many mangrove areas are still conserved. However, anthropogenic activities that promote degradation and metal contamination are beginning to reach worrying scales and may affect this ecosystem and its resources. The aim of the present study was to evaluate the contamination and bioaccumulation of metals (Cu, Cd, Cr, Pb, and Mn) by the mangrove crab (Ucides cordatus) and the potential risk to human health from ingestion of this crustacean, considered a fishing resource of great importance in the Amazon region. Specimens of U. cordatus, water, sediment, and leaves of Rhizophora mangle were collected from mangrove areas, being a conserved area and another anthropized for both states of Pará and Maranhão. Metallic concentrations in biotic and abiotic samples were quantified by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), with subsequent estimation of the Bioaccumulation Factor and multilevel analysis for the metals evaluated. To assess the risk of human consumption, daily intake (EDI), risk ratio (THQ) and number of eligible meals per month (CRmm) were estimated. Metal concentrations in the sediment were below the levels established by the legislation, differing from those observed for the water samples, where Cu, Mn and Pb, whose values were above the estuarine water limits. Even though, mostly of natural origin, it was observed that those elements are bioavailable and are being incorporated by biota. Concentrations of Cu, Cr, and Pb w... (Complete abstract click electronic access below) / Doutor

Given the importance of agricultural income for rural households, erratic weather conditions pose an austere threat to these households' livelihoods. This thesis explores ways through which households in agrarian economies smooth their consumption, engage in community networks, and readjust their labour allocation in response to shocks. In a setting of inherent risk, absence of institutional insurance, and labour market inefficiencies, poor households are often left to their own devices to cope with risk. The aim of this study is to examine the different risk-coping strategies adopted by households in rural India, assess their effectiveness, and derive implications for public policy. The results suggest that, in an environment characterised by agro-climatic risk, households are able to self-insure and smooth their consumption in the face of income shocks. Their coping mechanisms, however, may reduce their resilience to future shocks. In fact, small landholders tend to rely more heavily on their productive asset stock, while medium landholders find it optimal to preserve and accumulate their productive assets when exposed to exogenous income shocks. Households also change their labour allocation and reduce their self-employment in agriculture. Furthermore, households in rural areas can migrate to urban areas or engage in societal risk-sharing arrangements to mitigate the risk. The results of this thesis suggest that being part of a community network discourages individuals' migration and increases the likelihood of undertaking riskier activities. The findings also confirm the importance of portfolio adjustments and the diversification of household assets in buffering consumption. These conclusions form the basis of several policy implications, the most important of which is providing formal insurance schemes to encourage the accumulation of assets, technology, and skills.

Nell'ambito dell'economia dei disastri naturali ho elaborato uno studio macroeconomico e due microeconomici. A livello macro ho elaborato una meta-analisi della letteratura empirica sugli effetti dei disastri naturali in termini di costi diretti e indiretti. Ho analizzato gli effetti di caratteristiche del database,tecniche di stima, fattori di resilienza considerati e publication bias. Studi sui costi diretti che includono paesi Africani hanno 65% maggiore probabilità di riportare un risultato negativo e significativo mentre studi sui costi indiretti sembrano soffrire di publication bias. I lavori microeconometrici si focalizzano su due paesi africani. Nel primo analizzo gli effetti di un aumento della variabilità climatica sul consumo di beni alimentari delle famiglie in Uganda nel periodo 2005/06-2009/10. In media un incremento di 1% delle temperature porterebbe a una diminuzione del consumo di alimenti del 3-5% mentre le famiglie sarebbero in grado di contrastare variazioni delle precipitazioni con varie strategie. Nel secondo, con approccio multi-shock analizzo gli effetti di siccità e incremento dei prezzi di acquisto sullo stato nutrizionale di bambini in famiglie residenti in zone rurali del Senegal nel periodo 2009-2011. Singolarmente entrambi gli eventi sembrano avere effetti negativi sul livello nutrizionale. Tuttavia la concomitanza dei due eventi sembra non avere effetto sul peso dei bambini grazie a un positivo effetto reddito. / In this work I deal with the economics of natural disasters conducting one study at the macroeconomic level and two studies at the microeconomic level. In the first I conduct a meta-analysis of the macro literature on the direct and indirect costs of natural disasters. I investigate the effects of empirical design, estimation technique, resilience factors included and publication bias. I find that direct costs studies have 65% probability to report negative and significant results if they include African countries while indirect costs studies show publication bias. Second, I conduct a microeconometric analysis of the effects of weather variability on households food consumption in Uganda in the period 2005/06-2009/10. I show that on average 1% increase in maximum temperatures would reduce food consumption by 4-5% while precipitation amount and distribution would not affect household food consumption thanks to coping strategies. Finally I consider the effects of droughts and increasing purchasing prices on weight-for-age of children in rural households in Senegal using a multishock approach and a unique dataset (2009-2011). Results of drought(increase in prices) econometric analyis show deterioration in child weight-for-age. However, concomitance of drought and increasing prices would leave child weight-for-age unaffected thanks to positive income effects.