931 resultados para systems of quantities


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Includes bibliography

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Includes bibliography

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One of the main pesticides used in the cultivation of sugarcane in São Paulo State, Brazil, is Regent®800WG, the main active compound of which is fipronil. Fipronil is a potent insecticide that eliminates pests, including insects resistant to pyrethroids, organophosphates (OP) and carbamates (CA). There is little known on the toxic effects of fipronil on non-target organisms, such as tadpoles of frogs. It is possible that this compound carries a high toxicity for these organisms, since the pesticide can be incorporated into aquatic environments during the rainy season, a time which coincides with the time of amphibian reproduction and the occurrence of tadpoles in the aquatic environment in this region. Thus, the pesticide could be contributing to the decline of amphibians in the northwest region of São Paulo state due to its wide use. This study aimed to test the influence of Regent®800WG on some biochemical systems of tadpoles (such as antioxidant defense systems) at different stages of development. The results of analysis from in vivo exposures demonstrated that only a few parameters in the groups exposed to fipronil responded to exposure to Regent®800WG, results which indicate that the pesticide instigates biochemical responses in tadpoles. Although catalase and glucose-6-phosphate dehydrogenase (G6PDH) were unchanged during the experiments, glutathione-S-transferase (GST) was inhibited in tadpoles, and the activity of glutathione reductase (GR) varied according to the exposure period and pesticide concentration. This data demonstrated the influence of the fipronil formulation on the metabolism of tadpoles, and showed that it can increase their susceptibility to environmental contaminants. © 2013 Elsevier Ltd. All rights reserved.

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Purpose: Malnutrition is a strong predictor of mortality in hemodialysis patients. Several scoring systems for evaluating nutritional status have been proposed. However, they rely on different sets of anthropometric and laboratory markers to make a diagnosis of malnutrition and assess its impact on prognosis. To validate them, nutritional scores should be compared with clinical outcomes. Thus, the purpose of this study was to assess malnutrition by three different nutrition scoring systems and determine which best predicts mortality in hemodialysis patients. Methods: This prospective study included 106 adult chronic hemodialysis patients. Their mean age was 56.3 ± 14.9 years and mean body mass index 24.8 (21.8-28.9); 52 % were men and they had been on dialysis for 24 (5-55) months. Nutritional status was classified according to the diagnostic systems proposed by Wolfson et al. (Am J Clin Nutr 39(4):547-555, 1984), International Society of Renal Nutrition and Metabolism (ISRNM) (Fouque et al. in Kidney Int 73(4):391-398, 2008), and Beberashvili et al. (Nephrol Dial Transplant 25(8):2662-2671, 2010). During about 2 years of follow-up, mortality was assessed by Kaplan-Meier curves, log-rank, and Cox's models adjusted for diabetes, sex, C-reactive protein, time on dialysis, age, and fractional urea clearance. Results: Twenty-three deaths (21.5 %) occurred during the study period. According to the systems of Wolfson, Beberashvili, and the ISRNM, 54, 32, and 20 % of patients, respectively, had malnutrition. Both univariate and multivariate analyses showed that the ISRNM system was the only one that predicted poorer survival (fourfold higher death risk) in malnourished patients. Conclusions: The scoring system proposed by the ISRNM most accurately identifies patients at higher risk of death. © 2013 Springer Science+Business Media Dordrecht.

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Brazil is the world's largest producer of sugar cane and which in the state of São Paulo concentrate the greatest amount of sugar cane field of the country. The sugar-alcohol sector has the capacity to produce sufficient thermal and electrical energy to be used in their process of production and commercialize of surplus in electricity distribution network. Therefore it is necessary to evaluate the energy efficiency and rationality within the mill. Accordingly this research proposed analyze the sugar-alcohol mill's sectors globally and individually, located in the west center of the São Paulo state, using the valuation methodology employed by the Agência Nacional de Energia Elétrica (ANEEL) in the industries that do not have systems of cogeneration. In this analysis, the hyperboloids of load and potency were applied based on the indexes of potency factor and load factor that allow estimate the efficiency and rationality. © 2013 IEEE.

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To become competitive, ultimately, photovoltaics should have its costs reduced and use photovoltaic systems of greater efficiency. The main steps in this direction are the use of new materials, the improvement in the manufacture of modules and the adoption of techniques of maximum power point tracking and of solar tracking. This article aims at presenting the project and development of an azimuth and elevation solar tracker, based on a new conception of the positioning sensor, composed of an array of four photoresistors. The two direct current motors that operate in the vertical and horizontal axes are controlled by a proportional-integral microcontroller. The conditions of the project were low cost, small energy consumption and versatility. The microcontroller can also incorporate a maximum power point tracking algorithm. The performance of solar tracker prototype in the initial phase of field tests can be considered appropriate. © Institution of Engineers Australia, 2013.

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Neem oil is a biopesticide that disturbs the endocrine and neuroendocrine systems of pests and may interfere with molting, metamorphosis and cocoon spinning. The cocoon serves protective functions for the pupa during metamorphosis, and these functions are dependent on cocoon structure. To assess the changes in cocoon spinning caused by neem oil ingestion, Ceraeochrysa claveri larvae, a common polyphagous predator, were fed with neem oil throughout the larval period. When treated with neem oil, changes were observed on the outer and inner surfaces of the C. claveri cocoon, such as decreased wall thickness and impaired ability to attach to a substrate. These negative effects may reduce the effectiveness of the mechanical and protective functions of cocoons during pupation, which makes the specimen more vulnerable to natural enemies and environmental factors. © 2013 Elsevier Inc.

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Historically, the ichthyofauna of large Brazilian rivers has been subject to anthropogenic interference, such as impoundments. Currently, cage fish farming systems are a new source of impact on aquatic ecosystems. The objective of this study was to characterise the impact of freshwater fish farms on the feeding of five species of Neotropical freshwater fish. Specimens of Astyanax altiparanae, Galeocharax knerii, Iheringicthys labrosus, Pimelodus maculatus and Plagioscion squamosissimus were sampled in areas around two systems of cage fish farming (CF), and two control areas (CT) that were not influenced by this activity. Results show that there were significant changes in the diet of trophic generalist species (A. altiparanae, P. maculatus and I. labrosus) accompanied by a related increase in the condition factor values of these species in cage areas. Trophic specialist species, such as the carnivorous fish species G. knerii and P. squamosissimus, presented small differences between the CF and CT areas with regard to diet and showed no differences in other analyses performed. In conclusion, cage fish farms can affect the natural diet of trophic generalist fish species, directly affecting the nutritional status (condition factor), where food wastes was found to be one of the principal items consumed by this trophic guild. Results indicate that these species are responsible for recycling a great quantity of organic matter transferred by this type of activity, which, along with local fishery activities, contribute to mitigation of associated processes of eutrophication. © 2013 Elsevier B.V.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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This document, which is partly based on by the study Impacto de la Infraestructura de la Calidad en América Latina, is a second joint effort by the Economic Commission for Latin America and the Caribbean (ECLAC) and the German National Metrology Institute (PTB) to move towards a more detailed understanding of the role played by the Quality Infrastructure in opening up possibilities for the countries in the region to innovate and compete. Through methodological analysis and the realization of case studies at the national level in certain countries in the region, the document seeks to offer a more comprehensive picture of the impact of the Quality Infrastructure and its importance for the economic and social development of countries. The document analyzes various QI related aspects, with particular emphasis on a review of conceptual elements, the role of the QI in the innovation systems of countries and a brief analysis of a set of case studies in Latin American countries. It also identifies a series of challenges and limitations for carrying out impact studies. These elements are taken up again in the final conclusions of the book, where a number of policy recommendations are outlined.

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This report analyses the agriculture, health and tourism sectors in Saint Lucia to assess the potential economic impacts of climate change on the sectors. The fundamental aim of this report is to assist with the development of strategies to deal with the potential impact of climate change in Saint Lucia. It also has the potential to provide essential input for identifying and preparing policies and strategies to help advance the Caribbean subregion closer to solving problems associated with climate change and attaining individual and regional sustainable development goals. Some of the key anticipated impacts of climate change for the Caribbean include elevated air and sea-surface temperatures, sea-level rise, possible changes in extreme events and a reduction in freshwater resources. The economic impact of climate change on the three sectors was estimated for the A2 and B2 IPCC scenarios until 2050. An evaluation of various adaptation strategies for each sector was also undertaken using standard evaluation techniques. The key subsectors in agriculture are expected to have mixed impacts under the A2 and B2 scenarios. Banana, fisheries and root crop outputs are expected to fall with climate change, but tree crop and vegetable production are expected to rise. In aggregate, in every decade up to 2050, these sub-sectors combined are expected to experience a gain under climate change with the highest gains under A2. By 2050, the cumulative gain under A2 is calculated as approximately US$389.35 million and approximately US$310.58 million under B2, which represents 17.93% and 14.30% of the 2008 GDP respectively. This result was unexpected and may well be attributed to the unavailability of annual data that would have informed a more robust assessment. Additionally, costs to the agriculture sector due to tropical cyclones were estimated to be $6.9 million and $6.2 million under the A2 and B2 scenarios, respectively. There are a number of possible adaptation strategies that can be employed by the agriculture sector. The most attractive adaptation options, based on the benefit-cost ratio are: (1) Designing and implementation of holistic water management plans (2) Establishment of systems of food storage and (3) Establishment of early warning systems. Government policy should focus on the development of these adaption options where they are not currently being pursued and strengthen those that have already been initiated, such as the mainstreaming of climate change issues in agricultural policy. The analysis of the health sector placed focus on gastroenteritis, schistosomiasis, ciguatera poisoning, meningococal meningitis, cardiovascular diseases, respiratory diseases and malnutrition. The results obtained for the A2 and B2 scenarios demonstrate the potential for climate change to add a substantial burden to the health system in the future, a factor that will further compound the country’s vulnerability to other anticipated impacts of climate change. Specifically, it was determined that the overall Value of Statistical Lives impacts were higher under the A2 scenario than the B2 scenario. A number of adaptation cost assumptions were employed to determine the damage cost estimates using benefit-cost analysis. The benefit-cost analysis suggests that expenditure on monitoring and information provision would be a highly efficient step in managing climate change and subsequent increases in disease incidence. Various locations in the world have developed forecasting systems for dengue fever and other vector-borne diseases that could be mirrored and implemented. Combining such macro-level policies with inexpensive micro-level behavioural changes may have the potential for pre-empting the re-establishment of dengue fever and other vector-borne epidemic cycles in Saint Lucia. Although temperature has the probability of generating significant excess mortality for cardiovascular and respiratory diseases, the power of temperature to increase mortality largely depends on the education of the population about the harmful effects of increasing temperatures and on the existing incidence of these two diseases. For these diseases it is also suggested that a mix of macro-level efforts and micro-level behavioural changes can be employed to relieve at least part of the threat that climate change poses to human health. The same principle applies for water and food-borne diseases, with the improvement of sanitation infrastructure complementing the strengthening of individual hygiene habits. The results regarding the tourism sector imply that the tourism climatic index was likely to experience a significant downward shift in Saint Lucia under the A2 as well as the B2 scenario, indicative of deterioration in the suitability of the island for tourism. It is estimated that this shift in tourism features could cost Saint Lucia about 5 times the 2009 GDP over a 40-year horizon. In addition to changes in climatic suitability for tourism, climate change is also likely to have important supply-side effects on species, ecosystems and landscapes. Two broad areas are: (1) coral reefs, due to their intimate link to tourism, and, (2) land loss, as most hotels tend to lie along the coastline. The damage related to coral reefs was estimated at US$3.4 billion (3.6 times GDP in 2009) under the A2 scenario and US$1.7 billion (1.6 times GDP in 2009) under the B2 scenario. The damage due to land loss arising from sea level rise was estimated at US$3.5 billion (3.7 times GDP) under the A2 scenario and US$3.2 billion (3.4 times GDP) under the B2 scenario. Given the potential for significant damage to the industry a large number of potential adaptation measures were considered. Out of these a short-list of 9 potential options were selected by applying 10 evaluation criteria. Using benefit-cost analyses 3 options with positive ratios were put forward: (1) increased recommended design speeds for new tourism-related structures; (2) enhanced reef monitoring systems to provide early warning alerts of bleaching events, and, (3) deployment of artificial reefs or other fish-aggregating devices. While these options had positive benefit-cost ratios, other options were also recommended based on their non-tangible benefits. These include the employment of an irrigation network that allows for the recycling of waste water, development of national evacuation and rescue plans, providing retraining for displaced tourism workers and the revision of policies related to financing national tourism offices to accommodate the new climate realities.

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The economic impact of climate change on root crop, fisheries and vegetable production for Trinidad and Tobago under the A2 and B2 scenarios were modeled, relative to a baseline ―no climate change‖ case, where the mean temperature and rainfall for a base period of 1980 – 2000 was assumed for the years up to 2050. Production functions were used, using ARMA specifications to correct for serial autocorrelation. For the A2 scenarios, rainfall is expected to fall by approximately 10% relative to the baseline case in the 2020s, but is expected to rise thereafter, until by the 2040s rainfall rises slightly above the mean for the baseline case. For the B2 scenario, rainfall rose slightly above the mean for the baseline case in the current decade, but falls steadily thereafter to approximately 15% by the 2040s. Over the same period, temperature is expected to increase by 1.34C and 1.37C under A2 and B2 respectively. It is expected that any further increase in rainfall should have a deleterious effect on root crop production as a whole, since the above mentioned crops represent the majority of the root crops included in the study. Further expected increases in temperature will result in the ambient temperature being very close to the optimal end of the range for most of these crops. By 2050, the value of yield cumulative losses (2008$) for root crops is expected to be approximately 248.8 million USD under the A2 scenario and approximately 239.4 million USD under the B2 scenario. Relative to the 2005 catch for fish, there will be a decrease in catch potential of 10 - 20% by 2050 relative to 2005 catch potentials, other things remaining constant. By 2050 under the A2 and B2 scenarios, losses in real terms were estimated to be 160.2 million USD and 80.1 million USD respectively, at a 1% discount rate. For vegetables, the mean rainfall exceeds the optimal rainfall range for sweet peppers, hot peppers and melongene. However, while the optimal rainfall level for tomatoes is 3000mm/yr, other vegetables such as sweet peppers, hot peppers and ochroes have very low rainfall requirements (as low as 300 mm/yr). Therefore it is expected that any further decrease in rainfall should have a mixed effect on individual vegetable production. It is expected that any further increase in temperature should have a mixed effect on individual vegetable production, though model results indicated that as a group, an increase in temperature should have a positive impact on vegetable production. By 2050, the value of yield cumulative gains (2008$) for vegetables is expected to be approximately 54.9 million USD under the A2 scenario and approximately 49.1 million USD under the B2 scenario, given a 1% discount rate. For root crops, fisheries and vegetables combined, the cumulative loss under A2 is calculated as approximately 352.8 million USD and approximately 270.8 million USD under B2 by 2050. This is equivalent to 1.37% and 1.05% of the 2008 GDP under the A2 and B2 scenarios respectively by 2050. Sea Level Rise (SLR) by 2050 is estimated to be 0.255 m under A2 and 0.215 m under B2. GIS estimation indicated that for a 0.255 m sea level rise, combined with a 0.5 m high tide, there would be no permanent inundation of agricultural land in Trinidad. The total inundation area is 1.18 km2. This occurs only in the Caroni Watershed, on the western coast of Trinidad, and the areas are outside the Caroni Swamp. Even with an additional rise of 0.5 m to simulate a high rainfall event, the estimated inundated area is 4.67 km2, but with no permanent inundation, though likely to be subject to flooding. Based on eleven (11) evaluation criteria, the top potential adaptation options were identified: 1. Use of water saving irrigation systems and water management systems e.g. drip irrigation; 2. Mainstream climate change issues into agricultural management; 3. Repair/maintain existing dams; 4. Alter crop calendar for short-term crops; 5. Adopt improved technologies for soil conservation; 6. Establish systems of food storage; 7. Promote water conservation – install on-farm water harvesting off roof tops; 8. Design and implement holistic water management plans for all competing uses; 9. Build on- farm water storage (ponds and tanks); 10. Agricultural drainage; and 11. Installation of greenhouses. The most attractive adaptation options, based on the Benefit-Cost Ratio are: (1) Build on- farm water storage such as ponds and tanks (2) Mainstreaming climate change issues into agricultural management and (3) Water Harvesting. However, the options with the highest net benefits are, (in order of priority): (1) Build on- farm water storage such as ponds and tanks, (2) Mainstreaming climate change issues into agricultural management and (3) Use of drip irrigation. Based on the area burnt in Trinidad and Tobago between 2005 and 2009, the average annual loss due to fires is 1717.3 ha. At US$17.41 per carbon credit, this implies that for the total land lost to forest fires on average each year, the opportunity cost of carbon credit revenue is 74.3 million USD. If a teak reforestation programme is undertaken in Trinidad and Tobago, the net benefit of reforestation under a carbon credit programme would be 69 million USD cumulatively to 2050.

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A primeira parte deste trabalho aborda a simulação computacional de dinâmica molecular clássica da interação de sistemas matriciais constituídos de nanofios paralelos de Au simuladas em função do tempo. Como resultados foram encontrados os tempos de colisões entre os fios da matriz. A segunda parte deste trabalho utiliza dinâmica molecular clássica para simular cinco gerações de dendrímeros PAMAM, cada qual interagindo individualmente com um nanotubo de carbono em função do tempo resultando num motor molecular. Além disso, foram calculados os espectros de absorção deste sistema e foi verificado que eles são nanomotores controlados pela luz. Para todos estes sistemas foram calculadas energias cinética, potencial, total, velocidade, propriedades termodinâmicas como variação de entropia molar, capacidade molar térmica e temperatura in situ. Estas grandezas nos forneceram valiosas informações sobre o comportamento destes sistemas.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)