856 resultados para Fishs - Migration routes
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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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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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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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Migration towards Europe has surged over the past few years, overwhelming government authorities at the national and EU levels, and fuelling a xenophobic, nationalist, populist discourse linking migrants to security threats. Despite positive advances in the courts and worthy national initiatives (such as Italy’s Operation Mare Nostrum), the EU’s governance of migration and borders has had disastrous effects on the human rights of migrants. These effects stem from the criminalisation of migrants, which pushes them towards more precarious migration routes, the widespread use of administrative detention and the processing of asylum claims under the Dublin system, and now the EU–Turkey agreement. Yet, this paper finds that with the right political leadership, the EU could adopt different policies in order to develop and implement a human rights-based approach to migration that would seek to reconcile security concerns with the human rights of migrants. Such an approach would enable member states to fully reap the rewards of a stable, cohesive, long-term migration plan that facilitates and governs mobility rather than restricts it at immense cost to the EU, the member states and individual migrants.
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Hydropower dams block migration routes and disrupt longitudinal connectivity in rivers, thereby posing a threat to migratory fish species. Various fish passage solutions have been implemented to improve connectivity with varying success. A well-functioning passage solution must ensure safe and timely passage routes that are used by a substantial portion of the migrating fish. In this thesis, I report the results from telemetry studies where the behavior and survival of migrating Atlantic salmon spawners, post-spawners and smolts have been evaluated in relation to hydropower dam passage. I evaluate downstream passage performance at dams with no passage solutions in the River Klarälven, and with simple passage solutions in in the Winooski River. In the River Ätran, I study both upstream- and downstream passage performance at a dam with sophisticated passage solutions based on the best available technology. In addition, I have studied the survival and behavior of post-spawners and hatchery-released smolts. A substantial portion of the spawners survived spawning and initiated downstream migration. Most males migrated downstream in autumn following spawning, whereas females tended to stay in the river until spring. For hatchery-reared smolts, early release was associated with faster initiation of migration and higher survival compared to late release. Multiple dam passage resulted in high mortality for both smolts and kelts. For smolts, dam passage, even with simple passage solutions, was associated with substantial delay and mortality. High spill levels were linked to high survival and short delay for downstream migrating salmon. The best available passage solution, which consisted of a nature-like fishway and a low sloping intake rack to guide fish to a bypass, resulted in rapid passage of a large portion of the adult migrants.
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Loss of connectivity in impounded rivers is among the impacts imposed by dams, and mitigation measures such as fish passages might not accomplish their purpose of reestablishing an efficient bi-directional gene flow in the fish populations affected. As a consequence, fish populations remain fragmented, and a new interpopulational structure may develop, with increased risk of reduced genetic diversity and stochastic extinction. In order to evaluate the effects of the Gavio Peixoto Dam, which was constructed almost a century ago on the Jacar,-Gua double dagger u River in the Upper Parana River basin, Brazil, a comparative morphometric study was undertaken on the populations of the Neotropical migratory characid fish Salminus hilarii living up- and downstream of this dam. Population dynamics, spatial segregation, and habitat use by different age classes were monitored for 2 years. We found that segregation caused by the dam and long periods with no efficient connection by fish passages have led to fragmentation and interpopulational structuring of S. hilarii, as revealed by canonical variable analysis of morphometric features. The fish populations occupying the up- and downstream sections have succeeded in performing short-distance reproductive migrations in the main river and tributaries, have found suitable habitats for completing their life cycle, and have been able to maintain distinct small-sized populations so far.
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The present work analyzes the epidemiology of schistosomiasis in Brazil, its expansion, the attempts to control the disease, and the overall difficulties. The authors present the distribution of schistosomiasis intermediary hosts in Brazil, the migration routes of the human population, and disease distribution in highly and lowly endemic areas and isolated foci. They also analyze the controlling programs developed from 1977 to 2002, indicating the prevalence evolution and the reduction of disease morbi-mortality. In addition, the authors also evaluate controlling methods and conclude that: (a) no isolated method is able to control schistosomiasis, and every controlling program should consider the need of a multidisciplinary application of existing methods; (b) in long term, basic sanitation, potable water supply, as well as sanitary education, and community effective participation are important for infection control; (c) in short term, specific treatment at endemic areas, associated with control of intermediary hosts at epidemiologically important foci, are extremely relevant for controlling disease morbidity, although not enough for interrupting infection transmission.
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AimWe take a comparative phylogeographical approach to assess whether three species involved in a specialized oil-rewarding pollination system (i.e. Lysimachia vulgaris and two oil-collecting bees within the genus Macropis) show congruent phylogeographical trajectories during post-glacial colonization processes. Our working hypothesis is that within specialized mutualistic interactions, where each species relies on the co-occurrence of the other for survival and/or reproduction, partners are expected to show congruent evolutionary trajectories, because they are likely to have followed parallel migration routes and to have shared glacial refugia. LocationWestern Palaearctic. MethodsOur analysis relies on the extensive sampling of 104 Western Palaearctic populations (totalling 434, 159 and 74 specimens of Lysimachiavulgaris, Macropiseuropaea and Macropisfulvipes, respectively), genotyped with amplified fragment length polymorphism. Based on this, we evaluated the regional genetic diversity (Shannon diversity and allele rarity index) and genetic structure (assessed using structure, population networks, isolation-by-distance and spatial autocorrelation metrics) of each species. Finally, we compared the general phylogeographical patterns obtained. ResultsContrary to our expectations, the analyses revealed phylogeographical signals suggesting that the investigated organisms demonstrate independent post-glacial trajectories as well as distinct contemporaneous demographic parameters, despite their mutualistic interaction. Main conclusionsThe mutualistic partners investigated here are likely to be experiencing distinct and independent evolutionary dynamics because of their contrasting life-history traits (e.g. dispersal abilities), as well as distinct hubs and migration routes. Such conditions would prevent and/or erase any signature of co-structuring of lineages in space and time. As a result, the lack of phylogeographical congruence driven by differences in life-history traits might have arisen irrespective of the three species having shared similar Pleistocene glacial refugia.
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La Fibrosis Quística es la enfermedad autosómica recesiva mas frecuente en caucásicos. En Colombia no se conoce la incidencia de la enfermedad, pero investigaciones del grupo de la Universidad del Rosario indican que podría ser relativamente alta. Objetivo: Determinar la incidencia de afectados por Fibrosis Quística en una muestra de recién nacidos de la ciudad de Bogotá. Metodología: Se analizan 8.297 muestras de sangre de cordón umbilical y se comparan tres protocolos de tamizaje neonatal: TIR/TIR, TIR/DNA y TIR/DNA/TIR. Resultados: El presente trabajo muestra una incidencia de 1 en 8.297 afectados en la muestra analizada. Conclusiones: Dada la relativamente alta incidencia demostrada en Bogotá, se justifica la implementación de Tamizaje Neonatal para Fibrosis Quística en Colombia.
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In this paper, we present evidence that the long-distance migratory catfish Brachyplatystoma filamentosum, B. flavicans, B. vaillantii, Goslinia platynema and Lithodoras dorsalis spawn in the headstreams of the Amazon river and its tributaries and that the estuary of the Amazon is the main nursery ground utilized by their alevins. The impact of hydroelectric dams on their populations are discussed in terms of interruption to fish migration routes up river and to larvae moving down river, provided that the hypothesis above holds. Ways of mitigating the impact are also considered. © 1991.
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O HTLV foi descrito inicialmente associado a uma leucemia no Japão e a uma doença neurológica presente no Caribe. Logo foi evidenciado que o HTLV-II era endêmico entre Ameríndios e, particularmente, entre Índios brasileiros. A Amazônia brasileira é a maior área endêmica para o vírus e dessa forma, permitiu que fossem realizados vários estudos relacionados com a sua biologia, a busca de doença, informações epidemiológicas que incluíram uma bem definida distribuição geográfica, a definição dos modos de transmissão e manutenção do vírus em comunidades pequenas, epidemiologicamente fechadas, assim como contribuições para o diagnóstico laboratorial da infecção. Um novo subtipo molecular, denominado HTLV-IIc, foi adicionalmente descrito baseando-se no sequenciamento genético do vírus e na análise filogenética. Esse subtipo está presente em outras áreas do país, indicando que o HTLV também funciona como um marcador precioso das migrações humanas nas Américas no passado e um provável marcador dos costumes das populações atuais. O outro retrovírus humano, o HIV, ainda não é prevalente nas comunidades indígenas, apesar de que elas podem ser facilmente alcançadas em virtude das inúmeras facilidades de transmissão para o vírus.
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Pós-graduação em Ciências Biológicas (Zoologia) - IBB
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Two Amerindian populations from the Peruvian Amazon (Yanesha) and from rural lowlands of the Argentinean Gran Chaco (Wichi) were analyzed. They represent two case study of the South American genetic variability. The Yanesha represent a model of population isolated for long-time in the Amazon rainforest, characterized by environmental and altitudinal stratifications. The Wichi represent a model of population living in an area recently colonized by European populations (the Criollos are the population of the admixed descendents), whose aim is to depict the native ancestral gene pool and the degree of admixture, in relation to the very high prevalence of Chagas disease. The methods used for the genotyping are common, concerning the Y chromosome markers (male lineage) and the mitochondrial markers (maternal lineage). The determination of the phylogeographic diagnostic polymorphisms was carried out by the classical techniques of PCR, restriction enzymes, sequencing and specific mini-sequencing. New method for the detection of the protozoa Trypanosoma cruzi was developed by means of the nested PCR. The main results show patterns of genetic stratification in Yanesha forest communities, referable to different migrations at different times, estimated by Bayesian analyses. In particular Yanesha were considered as a population of transition between the Amazon basin and the Andean Cordillera, evaluating the potential migration routes and the separation of clusters of community in relation to different genetic bio-ancestry. As the Wichi, the gene pool analyzed appears clearly differentiated by the admixed sympatric Criollos, due to strict social practices (deeply analyzed with the support of cultural anthropological tools) that have preserved the native identity at a diachronic level. A pattern of distribution of the seropositivity in relation to the different phylogenetic lineages (the adaptation in evolutionary terms) does not appear, neither Amerindian nor European, but in relation to environmental and living conditions of the two distinct subpopulations.