874 resultados para Émigration
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Over the last decade, we have seen a massive increase in the construction of wind farms in northern Fennoscandia. Wind farms comprising hundreds of wind turbines are being built, with little knowledge of the possible cumulative adverse effects on the habitat use and migration of semi-domesticated free-ranging reindeer. We assessed how reindeer responded to wind farm construction in an already fragmented landscape, with specific reference to the effects on use of movement corridors and reindeer habitat selection. We used GPS-data from reindeer during calving and post-calving in the MalAyen reindeer herding community in Sweden. We analysed data from the pre-development years compared to the construction years of two relatively small wind farms. During construction of the wind farms, use of original migration routes and movement corridors within 2 km of development declined by 76 %. This decline in use corresponded to an increase in activity of the reindeer measured by increased step lengths within 0-5 km. The step length was highest nearest the development and declining with distance, as animals moved towards migration corridors and turned around or were observed in holding patterns while not crossing. During construction, reindeer avoided the wind farms at both regional and landscape scale of selection. The combined construction activities associated with even a few wind turbines combined with power lines and roads in or close to central movement corridors caused a reduction in the use of such corridors and grazing habitat and increased the fragmentation of the reindeer calving ranges.
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http://digitalcommons.colby.edu/atlasofmaine2005/1008/thumbnail.jpg
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http://digitalcommons.colby.edu/atlasofmaine2005/1019/thumbnail.jpg
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http://digitalcommons.colby.edu/atlasofmaine2009/1032/thumbnail.jpg
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In this study we evaluate the possibility of two routes of migration into the state of Maine. The first possible route would be for migrants to continue along the coast, north of the Maine/New Hampshire border, and later swinging inland across the interior. The second path is for migrants who come up the east coast and straight into Maine, spreading across the state as they move north. In order to evaluate these possible routes we utilize a citizen-science project that measures the spring arrival dates of migrants according to the biophysical regions of Maine (Wilson 2007). Independent t-Tests and maps indicate that there is a trend of birds continuing along the coast before moving inland; six of the nine species show this pattern. Of the nine birds studied, only the eastern phoebe showed a significant trend of moving directly inland and moving across the state. Two birds show non-significant patterns of migration which could indicate insufficient data, or random migration patterns. The results are not conclusive because several of the biophysical regions have less reporting, and so the relationships among regions regarding arrival dates are skewed. Continued data collection and analysis is recommended.
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China’s floating population, those individuals who have migrated between counties or provinces for a period of longer than 6 months, account for 79 million individuals. If intracounty migration is also included, the number jumps to 145 million individuals or over 11% of the total population. This study examines the geographical differences in short and long term migration using ArcGIS to manipulate the spatial GIS data. The study shows that both short and long term migration (in absolute numbers) occurs more frequently near cities and in coastal regions. However, by normalizing the data by population size, the study eliminates the problems of population size on the size of the migrants. Using this normalized data, the study finds that western and northern counties have a large number of migrants present relative to the size of the population. Determining where this floating population migrates helps explain regional inequalities in employment opportunities.
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Academic libraries are faced with a daunting series of challenges brought on by the digital revolution. In an era when millions of books, articles, images, and videos available instantaneously via the web, libraries across all institutional types are experiencing declining demand for their traditional services, built around the storage and dissemination of physical resources. At the same time, new demand for digital information services and collaborative learning spaces promise new areas of opportunity and engagement with patrons. A rapid and orderly transition to “the library of the future” requires difficult trade-offs, however, as no institution can afford to continue expanding both its commitment to comprehensive, local print collections as well as new investments in staff, technology, and renovations. This report illustrates how progressive academic libraries are evolving in response to these challenges, providing case studies and best practices in managing library space, staff, and resources.
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No Brasil, a recente reformulação do Exame Nacional de Ensino Médio (ENEM) e a criação do Sistema de Seleção Unificada (SISU), um mecanismo de admissão centralizado que aloca os alunos às instituições, promoveram mudanças relevantes no Ensino Superior. Neste artigo, investigamos os efeitos da introdução do SISU na migração e evasão dos alunos ingressantes a partir dos dados do Censo de Educação Superior. Para tal, exploramos a variação temporal na adesão das instituições ao SISU e encontramos que a adoção do SISU está associada a um aumento da mobilidade entre municípios e entre estados dos alunos ingressantes em 3.8 pontos percentuais (p.p) e 1.6 p.p., respectivamente. Além disso, encontramos um aumento da evasão em 4.5 p.p. Nossos resultados indicam que custos associados à migração e comportamento estratégico são importantes determinantes da evasão dos alunos.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Tinuvin P migration from Polyethyleneterephthalate (PET) bottles was investigated using several fatty-food simulants such as olive oil, soybean oil, n-heptane and iso-octane, at exposure conditions of 2-10 days at 40 degrees C (total immersion). The stability of several UV stabilizers (BHT, Cyasorb UV 5411, Tinuvin P, Tinuvin 326 and Tinuvin 327) in n-heptane and iso-octane was also studied. After 10 days at 40 degrees C, losses of 6% and 20% in iso-octane and n-heptane respectively, were verified for Tinuvin P. Other UV stabilizers at the same experimental conditions showed higher losses (up to 30% for Tinuvin 327). These results confirm that, when carrying out specific migration studies, the stability of the substance of interest should be established in the food simulant to avoid underestimating the real migration behaviour. In order to quantify UV stabilizer migration, n-heptane and iso-octane solutions were concentrated and directly analysed by SIM mode GC-MS. For olive and soybean oils, Tinuvin P was isolated using size-exclusion chromatography and quantified by SIM mode GC-MS. Iso-octane proved to be a move suitable fatty-food simulant than n-heptane for the migration study of Tinuvin P from PET. Higher levels of Tinuvin P migrated to olive and soybean oils rather than to n-heptane. These results suggest that the MERCOSUL recommended official methods for specific migration studies should be revised since the migration levels using n-heptane as a fatty-food simulant could be underestimated when compared to edible oils. Copyright (C) 1999 John Wiley & Sons, Ltd.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The aim of this work was to identify the degradation compounds produced during irradiation of multilayer polyamide 6 (PA-6) films and to study their migration into water and 95% ethanol food simulant. After irradiation of multilayer PA-6 films at 3, 7 and 12 kGy, degradation compounds were extracted using solid-phase microextraction, for which the time and temperature of extraction and stirring were optimized, and identified by gas chromatography-mass spectrometry. Caprolactam, 2-cyclopentylcyclopentanone and aldehydes, among other compounds, were identified in the headspace of the films. Polydimethylsiloxane was considered the best fiber for extraction. The optimum conditions of time, temperature and stirring to extract the compounds were 20 min, 80 degrees C and 225 rpm. For validation purposes, the compounds were quantified in water and 95% ethanol and the results showed high sensitivity, good precision and accuracy. Migration of compounds from irradiated and non-irradiated multilayer PA-6 films into water and 95% ethanol food simulants was carried out at 40 degrees C for 10 days. The method was efficient for the quantification of decaldehyde, 2-cyclopentylcyclopentanone and caprolactam that migrated from multilayer PA-6 films into food simulants.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The migration of diethylhexyl phthalate (DEHP) from PVC bags into LVPS (0.9% NaCl) and LVPS with cyclosporine at concentrations of 2.5 and 0.5 mg/ml was studied. PVC bags were placed in contact with these solutions and stored at 25 1 degrees C. They were taken for analysis each 30 min during 6 h and after this period at each 1 h until 12 h of contact. Water was used as reference, and exposed and analyzed under the same conditions. After contact, the solutions were submitted to extraction with hexane and analyzed by GC-FID. The results showed that DEHP did not migrate into water and LVPS during all the time. Also, no measurable amount of DEHP was detected during the first 3 h of contact between the PVC bag and the diluted cyclosporine solution. However, the amount of released DEHP reached a detectable level after 4 It of contact, increased until 6 h, stabilized, and increased again after 9-10 h. The 12 h of contact showed the highest DEHP levels for both cyclosporine concentrations. The DEHP migrated was 0.02-0.08% of that present in the bag. (c) 2005 Elsevier B.V. All rights reserved.