942 resultados para Environmental development
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Kumphawapi, which is Thailand’s largest natural freshwater lake, contains a >10,000-year-long climatic and environmental archive. New data sets (stratigraphy, chronology, hydrogen isotopes, plant macrofossil and charcoal records) for two sedimentary sequences are here combined with earlier multi-proxy studies to provide a comprehensive reconstruction of past climatic and environmental changes for Northeast Thailand. Gradually higher moisture availability due to a strengthening of the summer monsoon led to the formation of a large shallow lake in the Kumphawapi basin between >10,700 and c. 7000 cal. BP. The marked increase in moisture availability and lower evaporation between c. 7000 and 6400 cal. BP favoured the growth and expansion of vegetation in and around the shallow lake. The increase in biomass led to gradual overgrowing and infilling, to an apparent lake level lowering and to the development of a wetland. Multiple hiatuses are apparent in all investigated sequences between c. 6500 and 1400 cal. BP and are explained by periodic desiccation events of the wetland and erosion due to the subsequent lake level rise. The rise in lake level, which started c. 2000 cal. BP and reached shallower parts c. 1400 cal. BP, is attributed to an increase in effective moisture availability. The timing of hydroclimatic conditions during the past 2000 years cannot be resolved because of chronological limitations.
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O zooplâncton, particularmente os cladóceros, são organismos de água doce importantes na regulação da produção primária dos ecossistemas de água doce. No entanto, também podem adaptar-se a condições salobras. Tendo em conta as previsões no âmbito das alterações climáticas, a intrusão salina pode ocorrer a par com a subida de temperatura. As populações de água doce podem ficar vulneráveis aos efeitos interativos da salinidade e da temperatura, de acordo com os seus limites de tolerância e capacidade de adaptação ao stress ambiental. Assim, a presente tese analisou as interações resultantes das alterações destes agentes de stress em populações de cladóceros de água doce. Primeiro, comparou-se a halotolerância de diferentes genótipos de Simocephalus vetulus provenientes de populações de água doce e de água salobra de modo a avaliar a existência de uma componente genética de resistência à salinidade. A sensibilidade aguda dos genótipos variou na mesma gama de concentrações; todavia, todos os genótipos da população salobra, exceto um, foram mais tolerantes do que os de água doce, em termos de tempo à imobilização. Contudo, não foi possível estabelecer uma relação entre a performance reprodutiva em condições salobras e o contexto ambiental de origem destes genótipos. Mais, estes ensaios mostraram que as populações de água doce têm potencial para tolerar incrementos de salinidade. Como tal, pode-se concluir que a seleção a que os genótipos estão sujeitos no seu local de origem foi mais fraca do que o esperado. Segundo, investigou-se a capacidade de aclimatação de Daphnia galeata à salinidade e temperatura, de modo a avaliar a halotolerância de Daphnia a duas temperaturas num cenário de aclimatação multigeracional. O objetivo foi compreender se a pré-adaptação ao stress ambiental (20ºC e 25ºC versus 0 g/L e 1 g/L de NaCl) influenciou posteriormente as respostas a estes agentes de stress. Verificou-se uma tendência para um aumento de sensibilidade ao NaCl, a temperaturas mais elevadas. No entanto, este efeito foi anulado após nove gerações, mas apenas quando os organismos foram aclimatados aos dois agentes de stress em simultâneo (salinidade e temperatura elevada). Terceiro, demonstrou-se experimentalmente que a salinidade interferiu com a competição interespecífica, alterando a composição das comunidades zooplanctónicas. Este conjunto de evidências permitiu-nos refletir nos múltiplos impactos de agentes de stress, particularmente os relacionados com as previsões de alterações climáticas. Em paralelo aos estudos de natureza experimental, e numa perspetiva de Educação para o Desenvolvimento Sustentável (EDS), importa também promover o desenvolvimento de competências necessárias à compreensão de mudanças ambientais globais (e.g., o impacto da salinidade e da temperatura) para implementar estratégias de mitigação e adaptação. Neste contexto, foi realizada uma atividade com estudantes do ensino secundário, que se tornou uma boa oportunidade para a sua aprendizagem e aquisição de competências de interpretação de dados experimentais, assim como de sensibilização para as questões ambientais.
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During the last century mean global temperatures have been increasing. According to the predictions, the temperature change is expected to exceed 1.5ºC in this century and the warming is likely to continue. Freshwater ecosystems are among the most sensitive mainly due to changes in the hydrologic cycle and consequently changes in several physico-chemical parameters (e.g. pH, dissolved oxygen). Alterations in environmental parameters of freshwater systems are likely to affect distribution, morphology, physiology and richness of a wide range of species leading to important changes in ecosystem biodiversity and function. Moreover, they can also work as co-stressors in environments where organisms have already to cope with chemical contamination (such as pesticides), increasing the environmental risk due to potential interactions. Therefore, the objective of this work was to evaluate the effects of climate change related environmental parameters on the toxicity of pesticides to zebrafish embryos. The following environmental factors were studied: pH (3.0-12.0), dissolved oxygen level (0-8 mg/L) and UV radiation (0-500 mW/m2). The pesticides studied were the carbamate insecticide carbaryl and the benzimidazole fungicide carbendazim. Stressors were firstly tested separately in order to derive concentration- or intensity-response curves to further study the effects of binary combinations (environmental factors x pesticides) by applying mixture models. Characterization of zebrafish embryos response to environmental stress revealed that pH effects were fully established after 24 h of exposure and survival was only affected at pH values below 5 and above 10. Low oxygen levels also affected embryos development at concentrations below 4 mg/L (delay, heart rate decrease and edema), and at concentrations below 0.5 mg/L the survival was drastically reduced. Continuous exposure to UV radiation showed a strong time-dependent impact on embryos survival leading to 100% of mortality after 72 hours of exposure. The toxicity of pesticides carbaryl and carbendazim was characterized at several levels of biological organization including developmental, biochemical and behavioural allowing a mechanistic understanding of the effects and highlighting the usefulness of behavioural responses (locomotion) as a sensitive endpoint in ecotoxicology. Once the individual concentration response relationship of each stressor was established, a combined toxicity study was conducted to evaluate the effects of pH on the toxicity of carbaryl. We have shown that pH can modify the toxicity of the pesticide carbaryl. The conceptual model concentration addition allowed a precise prediction of the toxicity of the jointeffects of acid pH and carbaryl. Nevertheless, for alkaline condition both concepts failed in predicting the effects. Deviations to the model were however easy to explain as high pH values favour the hydrolysis of carbaryl with the consequent formation of the more toxic degradation product 1- naphtol. Although in the present study such explanatory process was easy to establish, for many other combinations the “interactive” nature is not so evident. In the context of the climate change few scenarios predict such increase in the pH of aquatic systems, however this was a first approach focused in the lethal effects only. In a second tier assessment effects at sublethal level would be sought and it is expectable that more subtle pH changes (more realistic in terms of climate changes scenarios) may have an effect at physiological and biochemical levels with possible long term consequences for the population fitness.
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Dissertação de mestrado, Aquacultura e Pescas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015
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Interest in China’s capacity for environmental governance is growing, in line with its environmental woes and exponential economic growth. Environmental policy efforts have lacked effectiveness, confirming the persistence of a disjuncture between promise and performance. This article contributes to the debate through the analytical lens of Environmental Policy Integration (EPI): a normative concept and governance regime indispensable to sustainable development. It finds that China,like most OECD countries, falls short of the concept. Despite encouraging recent changes, driven by the Hu-Wen regime, and encapsulated in the idea of scientific development, the analysis reveals weaknesses in all three EPI-type responses: normative, organisational and procedural. The disjuncture is confirmed, but drawing on EPI’s normative perspective, it is suggested that the reasons for this lie as much in the framing of the promise, as in the performance, or implementation, itself. Based on this interpretation and on China’s unique extreme characteristics, it is recommended that environmental policy objectives be given principled priority status, as a condition for effective governance.
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Water use invariably results in major impacts on river flows. Environmental Flows (EF) are defined as the quantity and quality of water that is needed to preserve the structure and the function of the river and riparian zone ecosystem and sufficient quantity of water to enable the survival and reproduction of aquatic organisms in different hydraulic habitats. This paper describes the criteria and methods used to determine EF and experiences with their application in Slovenia. The diversity of running waters of Slovenia demand special treatment and determination of EF for each individual section of the river system. Using hydrological, morphological and ecological criteria, two different approaches are used for the determination of EF in Slovenia, a rapid assessment method and a detailed assessment method. For both methods, data are then analyzed by an expert panel in order to determine an EF. Since 1994, more than 180 study sites have been examined for research and application of EF in Slovenia. Determination of EF for existing users has prioritized their water requirements so they can remain economically viable. Where new schemes are proposed, there has been much greater scope to prioritize ecosystem requirements. EF determination is receiving growing attention and will continue to increase in importance, driven by research that aids our understanding of flow-biota relationships and recent environmental policy and legislation at both the national and European level.
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Tese de doutoramento, Farmácia (Química Farmacêutica e Terapêutica), Universidade de Lisboa, Faculdade de Farmácia, 2015
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The United Nations Conference on Sustainable Development (or Rio+20) was conceived at a time of great concern for the health of the world economy. In this atmosphere ‘green economy’ was chosen as one of two central themes for the conference, building on a burgeoning body of literature on the green economy and growth. This research examines the relationship and influence between the double crisis and the rise of ‘greening’ as part of the solution. The aim is to understand what defines and distinguishes the proposals contained in twenty-four sources on the green economy (including policy documents by international agencies and think tanks, and research papers), and what is the meaning and implication of the rising greening agenda for sustainable development as it enters the 21st century. Through a systematic qualitative analysis of textual material, three categories of discourse that can illuminate the meaning and implication of greening are identified: ‘almost business as usual’, ‘greening’, and ‘all change’. An analysis of their relationship with Dryzek's classification of environmental discourse leads to the identification of three interrelated patterns: (1) scarcity and limits, (2) means and ends, and (3) reductionism and unity—which deepen our understanding of the tensions between emerging propositions. The patterns help explain the meaning and implications of greening for sustainable development, revealing an economisation and polarisation of discourses, the persisting weak interpretation of sustainable development, and a tension between the fixing or shifting of dominant socioeconomic paradigms that underpin its conceptualisation.
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An important feature of UK housing policy has been the promotion of consortia between local authorities, private developers and housing associations in order to develop mixed tenure estates to meet a wide range of housing needs. Central to this approach has been a focus on the management of neighbourhoods, based on the assumption that high densities and the inter-mixing of tenure exacerbates the potential for incivility and anti-social behaviour and exerts a disproportionate impact on residents' quality of life. Landlord strategies are therefore based on a need to address such issues at an early stage in the development. In some cases community-based, third sector organisations are established in order to manage community assets and to provide a community development service to residents. In others, a common response is to appoint caretakers and wardens to tackle social and environmental problems before they escalate and undermine residents’ quality of life. A number of innovative developments have promoted such neighbourhood governance approaches to housing practice by applying community development methods to address potential management problems. In the process, there is an increasing trend towards strategies that shape behaviour, govern ethical conduct, promote aesthetic standards and determine resident and landlord expectations. These processes can be related to the wider concept of governmentality whereby residents are encouraged to become actively engaged in managing their own environments, based on the assumption that this produces more cohesive, integrated communities and projects positive images. Evidence is emerging from a number of countries that increasingly integrated and mutually supportive roles and relationships between public, private and third sector agencies are transforming neighbourhood governance in similar ways. This paper will review the evidence for this trend towards community governance in mixed housing developments by drawing on a series of UK case studies prepared for two national agencies in 2007. It will review in particular the contractual arrangements with different tenures, identify codes and guidelines promoting 'good neighbour' behaviour and discuss the role of community development trusts and other neighbourhood organisations in providing facilities and services, designed to generate a well integrated community. The second part of the paper will review evidence from the USA and Australia to see how far there is a convergence in this respect in advanced economies. The paper will conclude by discussing the extent to which housing management practice is changing, particularly in areas of mixed development, whether there is a convergence in practice between different countries and how far these trends are supported by theories of governmentality.
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Thesis (Master's)--University of Washington, 2015
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Senior thesis written for Oceanography 445
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Finding the balance between economic development and preservation of the natural environment is a challenging yet important task. This is a particularly pressing issue in the case of China, as it is the largest and fastest-growing market for tourism. The purpose of this research is to examine Chinese tourists’ participation in nature-based, tourism activities by incorporating tourists’ environmental concern, measured by a revised New Environmental Paradigm (NEP) scale, into a tourism constraint-negotiation model. The responses of 409 Chinese tourists show environmental concern will positively affect tourists’ motivation, which, in turn, will affect their negotiation strategy and ultimately their participation behavior. The theoretical and managerial implications of this study are discussed in the context of the tourism literature.