988 resultados para environmental sensitivity
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Fossil fuels are the main energy sources of the modern industrial age. Very sophisticated processes have been developed to extract these resources, due to increased demand on a global scale, as the extraction of oil. However, the complexity of these processes can cause accidents such as the release of oil to seas and oceans. In this context, this study proposes to carry out the implementation of a system of information to charts of environmental sensitivity to oil and prepare maps of vulnerability to oil for the city of Caraguatatuba-SP. The implementation of the database with geographical information of coastal environments was appropriate to be provided by the Internet, allowing wide access of data. The maps of vulnerability are important tool developed for the Individual Emergency Plans, because they were developed in operational scale, appropriate to actions to combat oil.
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Oil spills cause serious damage to the cost life and environments. Those impacts affect ecologic and socio-economic resources (like fishing and tourism). Within this background, response actions have two main objectives: the contaminant removal, with the less additional impacts, and enhance environment restoration in order to make this process complete in the shortest time possible. The present work proposes to contribute for the emergency environmental management in cases of oil spills by systematization of relevant information for oil spill environmental sensitivity maps. The next stage was to insert all these data on a geographic database, which allows data access by web. Beside that, this work aimed to recommend suitable clean-up techniques for the ecosystems located on the study area, composed by the municipalities: Praia Grande, Mongaguá, Itanhaém and Peruíbe, belonging to Baixada Santista and Iguape, Cananéia and Ilha Comprida, south cost of São Paulo state. This area is situated between two important Brazilian ports: Santos and Paranaguá, and that make it under considerable accident risks. The results were all data inserted on the geodatabase and available to user recover the information by web consulting. With that, this work wishes to contribute to individual emergencial planning of the region.
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This present paper aims to identify the main response techniques for coastal and fluvial environments and analyze impacts on the application of these techniques. The literature review allowed us to understand since the establishment of first environmental sensitivity index map, in coastal and fluvial environment, until the possible impacts generated by the application of cleanup techniques in both environments. Studies related to freshwater environment are less common compared to coastal environment. For both environments the same techniques may be employed, as well as containment and recovery, or removal of oil in the affected areas. The most serious environmental impacts generated are due to the poor choice of technique to be applied or the lack of training of the cleaning crews. In Deepwater Horizon accident, Gulf of Mexico, 2010, application of dispersants, resulted in a mixture of oil and dispersing 52 times more toxic than the oil itself. In Brazil, the technique of vegetation removal by the cleaning staff in the accident on the river Guaecá, 2004, resulted in unnecessary elimination of vegetation, increasing the volume of waste. It was concluded that the freshwater environment often suffer more impacts by applying the techniques, once is necessary to access the banks, which normally have more vegetation and organisms than shoreline of coastal environment
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This study aimed to perform the analysis and characterization of environmental sensitivity to oil from Baixada Santista in the State of São Paulo. The work was done by integrating data of physical environmet, socio-economic activities and the biological / ecological provided by the Research Group on Environmental Sensitivity to Oil Spill in the Institute of Geosciences and Exact Sciences of UNESP “Julio de Mesquita Filho” wich works in the conjunction with the Program of Human Resources Training in Geosciences and Environmental Sciences Applied to the Oil and Gas (PRH-05) of the National Petroleum Agency (ANP). Were also performed descriptive statistical analysis, based on dispersion and trend parameters, which allowed to answer questions related to environmental sensitivity index (ISL) prevalence, the predominance of the ISL by environment and the predominance of the environments of the area, thus providing an overview of Baixada Santista’s main towns about sensitivity to oil. Analyses performed in this study may also help mitigate the environmental and socioeconomic impacts and contribute to contingency plans development for Baixada Santista
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Leaking of hydrocarbon in fuel underground storage tanks constitute object of concern for urban environmental management, because therefore they provoke damages to the physical, biological and socioeconomic environment. Though laws that regulate this essential activity exist, aiming at to prevent contamination with hydrocarbon, we observe that this still happens. This fact evidences that the selection of places for installation of gas stations has not considered the characteristics of the natural environment, implying in more critical consequences associated to the leaking. The objective of this work is to elaborate a chart applied to the gas stations in Rio Claro/SP. The determination of the Index of Environmental Sensitivity for elaboration of such chart was carried through breaking the selection of factors of Environmental Sensitivity of physical, biological and socioeconomic environment. The balance of these factors was given by means of Ad hoc consultation. The crossing of the information was carried through using the method of overlapping of overlays. The result is a chart that shows us areas with classes of high, middle and low Environmental Sensitivity. One gives credit that this type of material can be used as criterion in the selection of adjusted areas for installations of new gas stations and management of the already installed gas stations. The diagnosis of the current situation of the gas stations in the area and recommendations had also been elaborated.
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The environmental sensitivity charts to oil constitute an important tools for contingency planning and assessment of damage caused by oil spills. The main objective of this article is to evaluate the sensitivity of river dynamics to oil spills. Through the identification and mapping of fluvial geomorphological features will be assessed the importance of these resources in terms of sensitivity to oil spills. Through satellite images, was obtained the geomorphological mapping and geomorphological parameters were analysed, in order to characterize the environmental sensitivity to oil spills and derivatives. Therefore, the implementation of an environmental sensitivity mapping from geomorphological parameters contributes to the mapping of the environmental sensitivity to oil, which will assist in the containment and cleanup procedures in case of accidents in fluvial and terrestrial environments, that are slightly studied in Brazil
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La evaluación de la Sensibilidad Ambiental (SA) constituye un instrumento que permite establecer la capacidad del medio para asimilar, contener o atenuar determinados eventos degradantes para el mismo; dicha sensibilidad es función de las condiciones intrínsecas de los factores ambientales. El objetivo del presente trabajo es evaluar la SA de unidades de paisaje del periurbano de Mar del Plata para sostener las principales actividades desarrolladas en él. Estas unidades de paisaje fueron definidas mediante la integración de factores del medio natural y socioeconómico; éstos se ponderaron con un valor de sensibilidad que es función de las actividades. La integración de los resultados permitió obtener un índice final para cada una de las unidades, el cual es: Bajo (menor o igual a 5), Moderado (entre 6 y 9), Alto (entre 10 y 13) o Muy Alto (mayor o igual a 14).
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La evaluación de la Sensibilidad Ambiental (SA) constituye un instrumento que permite establecer la capacidad del medio para asimilar, contener o atenuar determinados eventos degradantes para el mismo; dicha sensibilidad es función de las condiciones intrínsecas de los factores ambientales. El objetivo del presente trabajo es evaluar la SA de unidades de paisaje del periurbano de Mar del Plata para sostener las principales actividades desarrolladas en él. Estas unidades de paisaje fueron definidas mediante la integración de factores del medio natural y socioeconómico; éstos se ponderaron con un valor de sensibilidad que es función de las actividades. La integración de los resultados permitió obtener un índice final para cada una de las unidades, el cual es: Bajo (menor o igual a 5), Moderado (entre 6 y 9), Alto (entre 10 y 13) o Muy Alto (mayor o igual a 14).
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La evaluación de la Sensibilidad Ambiental (SA) constituye un instrumento que permite establecer la capacidad del medio para asimilar, contener o atenuar determinados eventos degradantes para el mismo; dicha sensibilidad es función de las condiciones intrínsecas de los factores ambientales. El objetivo del presente trabajo es evaluar la SA de unidades de paisaje del periurbano de Mar del Plata para sostener las principales actividades desarrolladas en él. Estas unidades de paisaje fueron definidas mediante la integración de factores del medio natural y socioeconómico; éstos se ponderaron con un valor de sensibilidad que es función de las actividades. La integración de los resultados permitió obtener un índice final para cada una de las unidades, el cual es: Bajo (menor o igual a 5), Moderado (entre 6 y 9), Alto (entre 10 y 13) o Muy Alto (mayor o igual a 14).
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This Doctoral Thesis entitled Contribution to the analysis, design and assessment of compact antenna test ranges at millimeter wavelengths aims to deepen the knowledge of a particular antenna measurement system: the compact range, operating in the frequency bands of millimeter wavelengths. The thesis has been developed at Radiation Group (GR), an antenna laboratory which belongs to the Signals, Systems and Radiocommunications department (SSR), from Technical University of Madrid (UPM). The Radiation Group owns an extensive experience on antenna measurements, running at present four facilities which operate in different configurations: Gregorian compact antenna test range, spherical near field, planar near field and semianechoic arch system. The research work performed in line with this thesis contributes the knowledge of the first measurement configuration at higher frequencies, beyond the microwaves region where Radiation Group features customer-level performance. To reach this high level purpose, a set of scientific tasks were sequentially carried out. Those are succinctly described in the subsequent paragraphs. A first step dealed with the State of Art review. The study of scientific literature dealed with the analysis of measurement practices in compact antenna test ranges in addition with the particularities of millimeter wavelength technologies. Joint study of both fields of knowledge converged, when this measurement facilities are of interest, in a series of technological challenges which become serious bottlenecks at different stages: analysis, design and assessment. Thirdly after the overview study, focus was set on Electromagnetic analysis algorithms. These formulations allow to approach certain electromagnetic features of interest, such as field distribution phase or stray signal analysis of particular structures when they interact with electromagnetic waves sources. Properly operated, a CATR facility features electromagnetic waves collimation optics which are large, in terms of wavelengths. Accordingly, the electromagnetic analysis tasks introduce an extense number of mathematic unknowns which grow with frequency, following different polynomic order laws depending on the used algorithmia. In particular, the optics configuration which was of our interest consisted on the reflection type serrated edge collimator. The analysis of these devices requires a flexible handling of almost arbitrary scattering geometries, becoming this flexibility the nucleus of the algorithmia’s ability to perform the subsequent design tasks. This thesis’ contribution to this field of knowledge consisted on reaching a formulation which was powerful at the same time when dealing with various analysis geometries and computationally speaking. Two algorithmia were developed. While based on the same principle of hybridization, they reached different order Physics performance at the cost of the computational efficiency. Inter-comparison of their CATR design capabilities was performed, reaching both qualitative as well as quantitative conclusions on their scope. In third place, interest was shifted from analysis - design tasks towards range assessment. Millimetre wavelengths imply strict mechanical tolerances and fine setup adjustment. In addition, the large number of unknowns issue already faced in the analysis stage appears as well in the on chamber field probing stage. Natural decrease of dynamic range available by semiconductor millimeter waves sources requires in addition larger integration times at each probing point. These peculiarities increase exponentially the difficulty of performing assessment processes in CATR facilities beyond microwaves. The bottleneck becomes so tight that it compromises the range characterization beyond a certain limit frequency which typically lies on the lowest segment of millimeter wavelength frequencies. However the value of range assessment moves, on the contrary, towards the highest segment. This thesis contributes this technological scenario developing quiet zone probing techniques which achieves substantial data reduction ratii. Collaterally, it increases the robustness of the results to noise, which is a virtual rise of the setup’s available dynamic range. In fourth place, the environmental sensitivity of millimeter wavelengths issue was approached. It is well known the drifts of electromagnetic experiments due to the dependance of the re sults with respect to the surrounding environment. This feature relegates many industrial practices of microwave frequencies to the experimental stage, at millimeter wavelengths. In particular, evolution of the atmosphere within acceptable conditioning bounds redounds in drift phenomena which completely mask the experimental results. The contribution of this thesis on this aspect consists on modeling electrically the indoor atmosphere existing in a CATR, as a function of environmental variables which affect the range’s performance. A simple model was developed, being able to handle high level phenomena, such as feed - probe phase drift as a function of low level magnitudes easy to be sampled: relative humidity and temperature. With this model, environmental compensation can be performed and chamber conditioning is automatically extended towards higher frequencies. Therefore, the purpose of this thesis is to go further into the knowledge of millimetre wavelengths involving compact antenna test ranges. This knowledge is dosified through the sequential stages of a CATR conception, form early low level electromagnetic analysis towards the assessment of an operative facility, stages for each one of which nowadays bottleneck phenomena exist and seriously compromise the antenna measurement practices at millimeter wavelengths.
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Animals from flies to humans adjust their development in response to environmental conditions through a series of developmental checkpoints, which alter the sensitivity of organs to environmental perturbation. Despite their importance, we know little about the molecular mechanisms through which this change in sensitivity occurs. Here we identify two phases of sensitivity to larval nutrition that contribute to plasticity in ovariole number, an important determinant of fecundity, in Drosophila melanogaster. These two phases of sensitivity are separated by the developmental checkpoint called "critical weight"; poor nutrition has greater effects on ovariole number in larvae before critical weight than after. We find that this switch in sensitivity results from distinct developmental processes. In precritical weight larvae, poor nutrition delays the onset of terminal filament cell differentiation, the starting point for ovariole development, and strongly suppresses the rate of terminal filament addition and the rate of increase in ovary volume. Conversely, in postcritical weight larvae, poor nutrition affects only the rate of increase in ovary volume. Our results further indicate that two hormonal pathways, the insulin/insulin-like growth factor and the ecdysone-signaling pathways, modulate the timing and rates of all three developmental processes. The change in sensitivity in the ovary results from changes in the relative contribution of each pathway to the rates of terminal filament addition and increase in ovary volume before and after critical weight. Our work deepens our understanding of how hormones act to modify the sensitivity of organs to environmental conditions, thereby affecting their plasticity.
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The future broadband information network will undoubtedly integrate the mobility and flexibility of wireless access systems with the huge bandwidth capacity of photonics solutions to enable a communication system capable of handling the anticipated demand for interactive services. Towards wide coverage and low cost implementations of such broadband wireless photonics communication networks, various aspects of the enabling technologies are continuingly generating intense research interest. Among the core technologies, the optical generation and distribution of radio frequency signals over fibres, and the fibre optic signal processing of optical and radio frequency signals, have been the subjects for study in this thesis. Based on the intrinsic properties of single-mode optical fibres, and in conjunction with the concepts of optical fibre delay line filters and fibre Bragg gratings, a number of novel fibre-based devices, potentially suitable for applications in the future wireless photonics communication systems, have been realised. Special single-mode fibres, namely, the high birefringence (Hi-Bi) fibre and the Er/Yb doped fibre have been employed so as to exploit their merits to achieve practical and cost-effective all-fibre architectures. A number of fibre-based complex signal processors for optical and radio frequencies using novel Hi-Bi fibre delay line filter architectures have been illustrated. In particular, operations such as multichannel flattop bandpass filtering, simultaneous complementary outputs and bidirectional nonreciprocal wavelength interleaving, have been demonstrated. The proposed configurations featured greatly reduced environmental sensitivity typical of coherent fibre delay line filter schemes, reconfigurable transfer functions, negligible chromatic dispersions, and ease of implementation, not easily achievable based on other techniques. A number of unique fibre grating devices for signal filtering and fibre laser applications have been realised. The concept of the superimposed fibre Bragg gratings has been extended to non-uniform grating structures and into Hi-Bi fibres to achieve highly useful grating devices such as overwritten phase-shifted fibre grating structure and widely/narrowly spaced polarization-discriminating filters that are not limited by the intrinsic fibre properties. In terms of the-fibre-based optical millimetre wave transmitters, unique approaches based on fibre laser configurations have been proposed and demonstrated. The ability of the dual-mode distributed feedback (DFB) fibre lasers to generate high spectral purity, narrow linewidth heterodyne signals without complex feedback mechanisms has been illustrated. A novel co-located dual DFB fibre laser configuration, based on the proposed superimposed phase-shifted fibre grating structure, has been further realised with highly desired operation characteristics without the need for costly high frequency synthesizers and complex feedback controls. Lastly, a novel cavity mode condition monitoring and optimisation scheme for short length, linear-cavity fibre lasers has been proposed and achieved. Based on the concept and simplicity of the superimposed fibre laser cavities structure, in conjunction with feedback controls, enhanced output performances from the fibre lasers have been achieved. The importance of such cavity mode assessment and feedback control for optimised fibre laser output performance has been illustrated.
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Suboptimal maternal nutrition during gestation results in the establishment of long-term phenotypic changes and an increased disease risk in the offspring. To elucidate how such environmental sensitivity results in physiological outcomes, the molecular characterisation of these offspring has become the focus of many studies. However, the likely modification of key cellular processes such as metabolism in response to maternal undernutrition raises the question of whether the genes typically used as reference constants in gene expression studies are suitable controls. Using a mouse model of maternal protein undernutrition, we have investigated the stability of seven commonly used reference genes (18s, Hprt1, Pgk1, Ppib, Sdha, Tbp and Tuba1) in a variety of offspring tissues including liver, kidney, heart, retro-peritoneal and inter-scapular fat, extra-embryonic placenta and yolk sac, as well as in the preimplantation blastocyst and blastocyst-derived embryonic stem cells. We find that although the selected reference genes are all highly stable within this system, they show tissue, treatment and sex-specific variation. Furthermore, software-based selection approaches rank reference genes differently and do not always identify genes which differ between conditions. Therefore, we recommend that reference gene selection for gene expression studies should be thoroughly validated for each tissue of interest. © 2011 Elsevier Inc.
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Equisetum giganteum L., a giant horsetail, is one of the largest living members of an ancient group of non-flowering plants with a history extending back 377 million years. Its hollow upright stems grow to over 5 m in height. Equisetum giganteum occupies a wide range of habitats in southern South America. Colonies of this horsetail occupy large areas of the Atacama river valleys, including those with sufficiently high groundwater salinity to significantly reduce floristic diversity. The purpose of this research was to study the ecophysiological and biomechanical properties that allow E. giganteum to successfully colonize a range of habitats, varying in salinity and exposure. Stem ecophysiological behavior was measured via steady state porometry (stomatal conductance), thermocouple psychrometry (water potential), chlorophyll fluorescence, and ion specific electrodes (xylem fluid solutes). Stem biomechanical properties were measured via a 3-point bending apparatus and cross sectional imaging. Equisetum giganteum stems exhibit mechanical characteristics of semi-self-supporting plants, requiring mutual support or support of other vegetation when they grow tall. The mean elastic moduli (4.3 Chile, 4.0 Argentina) of E. giganteum in South America is by far the largest measured in any living horsetail. Stomatal behavior of E. giganteum is consistent with that of typical C3 vascular plants, although absolute values of maximum late morning stomatal conductance are very low in comparison to typical plants from mesic habitats. The internode stomata exhibit strong light response. However, the environmental sensitivity of stomatal conductance appeared less in young developing stems, possibly due to higher cuticular conductance. Exclusion of sodium (Na) and preferential accumulation of potassium (K) at the root level appears to be the key mechanism of salinity tolerance in E. giganteum. Overall stomatal conductance and chlorophyll fluorescence were little affected by salinity, ranging from very low levels up to half strength seawater. This suggests a high degree of salinity stress tolerance. The capacity of E. giganteum to adapt to a wide variety of environments in southern South America has allowed it to thrive despite tremendous environmental changes during their long tenure on Earth.