Associations between a one-shot delay discounting measure and age, income, education and real-world impulsive behavior

There has been discussion over the extent to which delay discounting – as prototypically shown by a preference for a smaller-sooner sum of money over a larger-later sum – measures the same kind of impulsive preferences that drive non-financial behavior. To address this issue, a dataset was analyzed containing 42,863 participants’ responses to a single delay-discounting choice, along with self-report behaviors that can be considered as impulsive. Choice of a smaller-sooner sum was associated with several demographics: younger age, lower income, and lower education; and impulsive behaviors: earlier age of first sexual activity and recent relationship infidelity, smoking, and higher body mass index. These findings suggest that at least an aspect of delay discounting preference is associated with a general trait influencing other forms of impulsivity, and therefore that high delay discounting is another form of impulsive behavior

Efeitos da agricultura intensiva na estrutura e funcionamento de riachos de cabeceira tropicais

Tropical regions hold the planet´s most biodiverse ecosystems. Despite its importance to biodiversity and conservation, anthropogenic activities are degrading these ecosystems, with unknown consequences for its functioning and structure. In between the several ecosystems through the tropics, freshwater ecosystems call attention, due to its small fraction of area comparing to terrestrial ecosystems, that represent an enormous importance for human surviving and developing. Headwater streams constitute the majority of water bodies in a catchment, and therefore, it is essential for the health of the entire freshwater ecosystems. Several headwater streams are inserted in agricultural lands, suffering from the pressures from agricultural intensification. Therefore, this thesis was developed aiming to understand what are the main pressures that tropical headwater streams has been suffering, worldwide and locally in the Corumbataí river basin. The first chapter will contribute to understanding what are the main issues that tropical streams have been experiencing, focusing on agricultural multiple stressors and climate change effects. The second chapter analyzes how the conversion of low-intensity pasturelands to high-intensity bioenergy crops changes the water quality parameters in streams located in the Corumbataí river basin and also examines how important are the riparian forests in the headwater zone to provide better water quality in bioenergy crops. The third chapter investigates how water quality and climatic characteristics affect benthic biofilm community dynamics in tropical headwater streams in the Corumbataí river basin. The results have shown the existence of several knowledge gaps about tropical streams, mainly related to the effects of climate change, multiple stressors and the lack of policies and mitigation strategies for climate change. In relation to water quality, we found that the conversion of low-intensity pastures to high-intensity bioenergy crops are degrading water quality. Riparian forests in the springhead zone have demonstrated to be essential in providing water quality in bioenergy crops, especially in the wet season. The benthic biofilm community seems to be controlled mainly by climate characteristics and not by nutrient availability as observed in temperate streams. Therefore, a climate change scenario, the benthic biofilm will be strongly affected, with consequences in the functioning of tropical headwater streams. To reduce the negative impacts of intensive agriculture and climate change, we recommend the implementation of riparian forests, with special attention to the springhead area and also the implementation of best agricultural practices in tropical agriculture to ensure the sustainability of tropical freshwater resources.As regiões tropicais possuem os ecossistemas mais biodiversos do planeta. Apesar da sua importância na manutenção da biodiversidade, as atividades antrópicas estão degradando esses ecossistemas, gerando consequências negativas para sua estrutura e funcionamento. Entre os diversos ecossistemas tropicais, as águas doces chamam a atenção por ocupar uma pequena área em comparação com ecossistemas terrestres, porém, representam grande importância para a sobrevivência e desenvolvimento humano. Os riachos de cabeceira representam a maior parte dos corpos aquáticos em uma microbacia e, portanto, sua conservação é essencial para a saúde de toda a rede de drenagem de água doce. Diversos riachos de cabeceira estão inseridos em ecossistemas agrícolas, sofrendo as consequências da agricultura intensiva. Nesse sentido, esta tese foi desenvolvida com o intuito de entender quais são os principais impactos que os riachos de cabeceira tropicais vêm sofrendo, globalmente e localmente na bacia do rio Corumbataí (SP, Brasil). O primeiro capítulo contribui para entender quais os principais problemas que riachos tropicas estão sofrendo, focando nos múltiplos estressores advindos da agricultura e efeitos de mudanças climáticas. O segundo capítulo analisa como a conversão de pastos para cultivo de cana de açúcar modifica a qualidade da água em riachos da bacia do rio Corumbataí e também analisa o quão fundamentais são as florestas nas áreas de nascente para manter a qualidade da água em plantios de cana de açúcar. O terceiro capítulo analisa como a qualidade da água e características climáticas influenciam biofilmes bentônicos em riachos de cabeceira na bacia do rio Corumbataí. Os resultados demonstraram a existência de diversos tópicos que necessitam de maior entendimento, principalmente relacionados às mudanças climáticas e estressores múltiplos e a falta de políticas e estratégias de mitigação para os efeitos de mudanças climáticas. Em relação à qualidade da água, demonstrou-se que a conversão de pastos para cultivo de cana de açúcar reduz a qualidade da água. A presença de florestas nas nascentes demonstrou ser essencial na manutenção da qualidade da água em plantios de cana. Os biofilmes bentônicos demonstraram ser controlados principalmente por características sazonais e não pela disponibilidade de nutrientes como observado em riachos temperados. Portanto, essa comunidade será severamente afetada diante das mudanças climáticas, com consequências no funcionamento de riachos de cabeceira tropicais. Para reduzir os efeitos negativos da agricultura intensiva e das mudanças climáticas, recomenda-se a implementação de florestas ripárias, com especial atenção às áreas de nascentes. Também se recomenda a implementação de boas práticas agrícolas na agricultura para garantir a sustentabilidade dos recursos hídricos tropicais

A comunidade perifítica e suas relações com a qualidade da água no reservatório de Itupararanga (SP, Brasil)

O reservatório de Itupararanga representa grande importância na bacia hidrográfica do rio Sorocaba devido aos usos múltiplos que este ecossistema propicia à população. Dentre as diversas atividades que usufruem dos serviços ambientais desse reservatório, podemos citar o abastecimento de água potável, irrigação, recreação, navegação e turismo. Dessa forma, o presente estudo objetivou estudar os estoques de carbono e as relações da comunidade periférica (biomassa e composição específica) com a qualidade da água no reservatório de Itupararanga. Para isso, foram realizadas cinco campanhas de amostragem em quatro estações amostrais ao longo do reservatório em duas espécies de macrófitas aquáticas. A biomassa perifitica aderida às raízes da macrófita aquática. Eichhornia spp. apresentou variação de 0,9 mg.m2 a 12,5 mg.m2 e a biomassa perifitica aderida às raízes da macrófita aquática Polygonum punctatum apresentou variação de 0,5 mg.m2 a 3,9 mg.m2 e mostraram-se controladas principalmente pelo regime hidrológico e pelas concentrações de nutrientes na água. Os estoques de carbono da comunidade perifitica aderida às raízes de Eichhornia spp. e nos pecíolos de P. punctatum variaram de 0,3 mgC.m2 a 2,5 mgC.m2 e 0,1 mgC.m2 a 1,2 mgC.m2 respectivamente. Já em relação à composição específica de algas perifiticas, foi encontrado um total de 156 táxons divididos em 8 classes e a densidade total das espécies variou de 10,2 mil a 171,8 mil indivíduos por milímetro quadrado. Em relação à qualidade da água, o reservatório de Itupararanga apresentou em diversas momentos concentrações acima do máximo permitido para fósforo total e abaixo do mínimo permitido para oxigênio dissolvido segundo a resolução CONAMA 357/2005. A comunidade de algas perifíticas mostrou-se controlada por...The Itupararanga reservoir has great importance in the Sorocaba River basin due to the multiple uses that uses that this ecosystem provides to the population. Among the many activities that take benefit of the environmental services from this reservoir, we can cite the drinking water supply, irrigation, recreation, navigation and tourism. Therefeore, this study aimed to study the carbon stocks and the relationships of the periphytic community (biomass and species composition) with the quality of the water in the reservoir Itupararanga. For this, five sampling campaigns in four sampling stations along the reservoir in two species of aquatic macrophytes were performed. The periphyton biomass attached to the roots of the aquatic macrophyte Eichhornia spp. presented a variation of 0.9 mg.m2 to 12,5 mg.m2 and periphyton biomass attached to the aquatic macrophyte Polygomum punctatum showed variation of 0,5 mg.m2 to 3.9 mg.m2 and were controleed mainly by the hydrological regime and nutrient concentrations in the water. The periphytic community carbon stocks attached to the roots of eichhornia spp. and the petioles of P. punctatum ranged from 0.3 mgC.m2 to 2.5 mgC.m2 and 0.1 mgC.m2 to 1.2 mgC.m2 respectively. In relation to the species composition of periphytic algae, it has been found a total of 156 taxa divided into eight classes and the overall density of the species ranged from 10,200 to 171,800 individuals per square millimeter. In relation to the water quality, the Itupararanga reservoir performed in several times above the maximum allowed concentrations for total phosphorus and below the minimum allowable concentrations for dissolved oxygen according to CONAMA 357/2005 resolution. The community of periphytic algae has shown to be controlled by spatial and temporal patterns, such as substrate type, the sampling stations... (Complete abstract click electronic access below)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Biomass and elemental composition (C, N, H) of the periphytic community attached to Polygonum punctatum Ell. in a subtropical reservoir and its relationship to environmental factors

The periphytic communities in Brazilian reservoirs have been studied widely due to their importance for the assimilation of nutrients and their role at the base of the food chain. The objective of the present work was to analyse the environmental variables that influence the development of periphytic communities attached to stalks of the aquatic macrophyte Polygonum punctatum Ell. Five sample collections were made during 2010 at two sites in the Itupararanga reservoir (Ibiua, Sao Paulo, Brazil). The macrophyte was collected, and the periphytic community attached to its stalks was scraped off with a brush and jets of distilled water. Using a PLS analysis, we observed that 94.3% of the variation in periphyton biomass could be explained by concentrations of nitrate, conductivity, dissolved oxygen, water clarity and dissolved inorganic phosphorous. According to the indices applied, in 2010 the biomass of the periphytic community in the reservoir was low and predominantly heterotrophic, and the concentration of carbon in the periphyton was lower than that found in previous studies of this community.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

A new spatial estimation model and source apportionment of aliphatic hydrocarbons in coastal surface sediments of the Nayband Bay, Persian Gulf

Hydrocarbons, originating from oil and gas industries, are considered a potential risk for Nayband Bay, a natural marine park with extended mangroves, located on the north coastlines of the Persian Gulf, Iran. This paper determines the potential sources and spatial distribution of hydrocarbons, especially aliphatic hydrocarbons (AHCs), in Nayband Bay through the simultaneous application of three indices in the coastline surface sediments. To this end, a field study was conducted in the inter-tidal coastal zones and wetlands. Sediment samples were taken from surface layers along four transects with four sampling points at different distances from the gulf. The hydrocarbon compounds of the samples including AHCs, total petroleum hydrocarbons, and heavy metals (Ni, V as crude oil indicators) were analyzed and classified to discover the pollution indicators. Pearson pairwise correlation and cluster analyses along with pollution indices were employed to describe the spatial distribution pattern of hydrocarbons, identify hot spots, and determine the potential origin of AHCs. Different interpolation scenarios based on topographic and oceanic features were proposed to detect the spatial dynamics of AHCs. The results revealed that hydrocarbons mainly originated from anthropogenic sources including oil and gas industries located far from the affected area. It was also concluded that the long-distance pollution transfer was based on oceanic currents and wind direction in the bay. The proposed scenarios showed that the mean concentration values of total organic carbon and total organic material vary in the range of 0.19 ppm to 0.4 ppm and 2.88 ppm to 3.20 ppm, respectively.No sponso

Eucalyptus Short-Rotation Management Effects on Nutrient and Sediments in Subtropical Streams

Forested catchments generally present conserved aquatic ecosystems without anthropogenic disturbances; however, forest management operations can degrade these environments, including their water quality. Despite the potential degradation, few studies have analyzed the effects of forest management in subtropical regions, especially in forest plantations with intensive management, such as Eucalyptus plantations in Brazil. The intensive management of those plantations is characterized by fast-growing, short rotation cycles, and high productivity. This study aimed to assess the effects of Eucalyptus plantations harvesting on the concentration and exportation of nutrients and suspended solids in subtropical streams. Results showed that clear-cut harvesting and subsequent forest management operations do not alter most of the concentration of nitrate, potassium, calcium, and magnesium. The concentration of suspended solids increased during the first year after timber harvesting in all studied catchments, however, the increases were statistically significant in only two catchments. In the first year after harvest, it was observed an increment of water yield/precipitation ratio at three catchments, which also increased export of nutrients and suspended solids. Our results showed that harvesting of fast-growing Eucalyptus forest plantations partially affected sediment exports and did not compromise water quality in the studied catchments. However, the catchment land-use design, especially related to road density and land-use composition, showed significant relationship with sediment exportation