961 resultados para Fate of discards


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Desde finales de los 70 la piratería se convirtió en un problema para Nigeria. Con el tiempo adquirió características del crimen organizado y en 2010 se transformó en un problema transnacional, afectando a Estados del golfo de Guinea. Así, a través de una base conceptual, el estudio de caso concluyó que los factores internos –como la pobreza, debilidad estatal y marginalización- y externos –siendo ellos la falta de políticas internas destinadas a las aguas y la ausencia de estrategias marítimas en la región- de la piratería, crearon una dinámica para que dicha actividad se convirtiera en una amenaza a la seguridad marítima del golfo de Guinea, tomando como referencia a Benín y Togo. Siguiendo la línea argumentativa, se demuestra que la búsqueda de una solución a la delincuencia marítima ha generado interacciones de seguridad que sugieren las primeras fases de un posible complejo de seguridad regional.

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La pesca d'arrossegament practicada al mar Mediterrani incideix sobre un rang batimètric molt ampli i afecta a nombrosos tipus de fons que presenten comunitats molt diversificades, on les espècies de peixos, crustacis, cefalòpodes, altres mol·luscs, equinoderms i d'altres macroorganismes epibentònics interaccionen entre si. D'aquí la importància de caracteritzar amb una aproximació multiespecífica els fons explotats, com la que aquí hem dut a terme, prenent en consideració no tan sols les espècies d'interès comercial sinó totes les espècies que conformen la comunitat. Els objectius concrets d'aquesta tesi estan centrats en l'estudi qualitatiu i quantitatiu dels descartaments produïts per la pesca d'arrossegament que efectua la flota espanyola en la zona del Golf de Lleó, i en aspectes relacionats a millorar la selectivitat de les xarxes emprades canviant el disseny de la malla tradicional per malla quadrada. El mostreig s'ha dut a terme a bord d'una embarcació d'arrossegament comercial, amb una freqüència setmanal, dins el període comprès entre març del 1998 i març del 2000. En total s'han analitzat 68 pesques. Totes les mostres estudiades provenen del primer vol del dia i s'han capturat a fondàries entre 50 i 500 metres. De tot el volum capturat durant l'estudi s'han identificat un total de 307 espècies pertanyent a diversos grups taxonòmics. El grup taxonòmic majoritari és el dels peixos amb 133 espècies, seguit dels crustacis, els cefalòpodes, els equinoderms i finalment el grup d'altres invertebrats. L'espècie més capturada en nombre a la pesquera del Golf de Lleó ha estat la cervellina (Leptometra phalangium) i les més capturades en biomassa han estat la sardina (Sardina pilchardus) i el lluç mediterrani (Merluccius merluccius smiridus). Pel total de la captura la fracció descartada en nombre d'individus representa el 71% mentre que la biomassa descartada és de l'ordre del 36%. La causa més important en quant a quantitat de rebuig produït és la que respon al compliment de la normativa vigent, ja sigui per les talles mínimes legals o per les captures acompanyants permeses. Els majors descartaments estacionals en termes d'abundància es donen a la primavera i l'estiu, coincidint amb l'època de reclutament de la majoria de les espècies explotades. En canvi, els descartaments estacionals en termes de biomassa són excepcionalment elevats a l'estiu i estan provocats per la captura massiva de sardina (S. pilchardus) durant aquesta època de l'any. El rebuig expressat tant en nombre com en pes disminueix en funció de l'estrat de fondària, essent la quantitat descartada major en l'estrat A (50-200 m) i menor en l'estrat C (>400 m). S'ha comprovat que el disseny de malla quadrada aplicat al cóp de les xarxes d'arrossegament fa augmentar dràsticament, tant en nombre com en pes, el percentatge d'individus escapats, disminuint a la vegada la quantitat de descartament. També s'aconsegueix un augment de la mida de primera captura (L50) de totes les espècies excepte en la bruixa de quatre taques (Lepidorhombus boscii). A més es redueix l'impacte de la pesca sobre els estocs d'individus juvenils, sobretot d'espècies que presenten una secció de cos rodona com el lluç mediterrani (M. merluccius smiridus) i el verat (Scomber scombrus), disminuint així la sobrepesca de creixement i de reclutament al mateix temps que s'assegura i es millora la venda d'exemplars de mida legal.

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Procesos hidrodinámicos determinan, en un alto grado la calidad del agua en embalse, sin embargo dichos procesos han sido tradicionalmente olvidados en la gestión de embalse. En esta tesis se presentan evidencias de los principales procesos hidrodinámicos que ocurren en un embalse Mediterráneo a escala de cuenca a través de campañas experimentales y modelización numérica; y su influencia en la dinámica de poblaciones de fitoplancton. Dichos procesos son principalmente la generación de ondas internas o secas y la intrusión del río. La presencia de viento periódico genera secas forzadas, amplificando los modos cercanos al periodo del viento, de manera que modos verticales altos, considerados como raros en la naturaleza, tienden a dominar en el sistema.

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Ao ter como base geral de pesquisa – A Europa diante do fenómeno migratório - a procura de uma nova Humanização – o objectivo deste trabalho consistiu na análise de algumas formas de manifestação e do impacto deste fenómeno nas sociedades democráticas inseridas nesse espaço. A consciência que as migrações têm seguido a história do mundo e as civilizações e que a sua análise permite avaliar o destino de seres humanos que partem em busca de soluções para as suas vidas. A convicção que a configuração das migrações tem um amplo significado social, cultural e económico e que uma política de imigração fechada, repressiva ou redutora do seu verdadeiro significado pode dividir a Humanidade. O receio que gera a continuidade de uma visão unilateral do Mundo e o esquecimento das condições existenciais difíceis de alguns países de emigração. A renúncia de alguns em escutar um discurso carecido de autenticidade e em apoiar um diálogo comprometido com alguns pressupostos ideológicos pouco claros. O desejo de participar na denúncia da propagação de atitudes facilitadoras dos sentimentos racistas e xenófobos. O repúdio pelo desnorteamento ontológico traduzido pela defesa de certas atitudes persecutórias infringidas aos imigrantes clandestinos. A adopção de uma política basicamente norteada pelo controlo das fronteiras e pela exploração económica dos imigrantes. A indignação pelo esquecimento ou negligência na vigilância e aplicação dos direitos fundamentais, em concreto, o direito ao uso da liberdade, a uma vida familiar normal, situações que lesam muitos. Foram, em suma, as razões que motivaram o trabalho. Porque, igualmente o exercício da cidadania e a inserção num espaço mundial em transformação requerem a actualização da leitura das relações dos homens entre eles e com as formas espaciais; porque o papel dos imigrantes na economia contemporânea é sentido como algo fundamental, e também a importância do seu lugar na estratégia de um desenvolvimento sustentável deve ser demonstrada e respeitada, desejou-se partilhar com outros a oportunidade de defender a participação colectiva sob princípios e premissas mais humanistas, e considerados fundamentais, para a construção de uma política de imigração digna, mais abrangente e indutora de pontes abertas e não de áreas amuralhadas.

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Quis o curso da história que os destinos da África do Sul e de Israel se cruzassem. Dois «povos eleitos» - afrikaners e judeus - partilharam incompreensões, rejeições e isolamentos. As diferenças separaram-nos, mas os estigmas presentes na sociedade internacional contemporânea reaproximaram-nos. Encerrados no «laager» e em «Massada», respetivamente, afrikaners e judeus encontraram um importante caminho da sobrevivência nacional numa cooperação estreita, até mesmo nos domínios mais sensíveis.

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La primera parte del artículo muestra cómo el período de transición que vive actualmente la Comunidad Andina (CAN) puede conducir a su liquidación o a la redefinición de su sentido y de su alcance. La forma en que las dinámicas sudamericanas pueden incidir en la suerte de la CAN, de acuerdo a que si las cuestiones energéticas y de infraestructura amplían la fragmentación ideológico- política o si impulsan una reestructuración plural de la integración regional, son abordadas en la segunda parte de este trabajo.

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A wide range of issues relating to the presence and fate of pesticides and other micro-organic contaminants (MOCs) in surface freshwater sedimentary environments is reviewed. These issues include the sources, transport and occurrence of MOCs in freshwater environments; their ecological effects; their interaction with sedimentary material; and a range of processes related to their fate, including degradation, diffusion in bed sediments, bioturbation and slow contaminant release. An emphasis is placed on those processes-chemical, physical or biological-in which sediments play a role in determining the fate of micro-organics in freshwater environments. The issues of occurrence, source and transport, and the ecological effects of micro-organics are introduced more briefly, the focus where these aspects are concerned being largely on pesticides. In the concluding section, key points and issues relating to the study of micro-organics in freshwater environments are summarised and areas where initial or further research would be welcome are highlighted. It is hoped that this paper will both form a useful reference for workers in the field of micro-organic contaminants, and also stimulate new work in the freshwater environment and beyond. (C) 2003 Elsevier Science Ltd. All rights reserved.

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A wide range of issues relating to the presence and fate of pesticides and other micro-organic contaminants (MOCs) in surface freshwater sedimentary environments is reviewed. These issues include the sources, transport and occurrence of MOCs in freshwater environments; their ecological effects; their interaction with sedimentary material; and a range of processes related to their fate, including degradation, diffusion in bed sediments, bioturbation and slow contaminant release. An emphasis is placed on those processes-chemical, physical or biological-in which sediments play a role in determining the fate of micro-organics in freshwater environments. The issues of occurrence, source and transport, and the ecological effects of micro-organics are introduced more briefly, the focus where these aspects are concerned being largely on pesticides. In the concluding section, key points and issues relating to the study of micro-organics in freshwater environments are summarised and areas where initial or further research would be welcome are highlighted. It is hoped that this paper will both form a useful reference for workers in the field of micro-organic contaminants, and also stimulate new work in the freshwater environment and beyond. (C) 2003 Elsevier Science Ltd. All rights reserved.

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The fate of biodiversity is intimately linked to agricultural development. Policy reform is an important driver of changes in agricultural land-use, but there is considerable spatial variation in response to policy and its potential impact on biodiversity. We review the links between policy, land-use and biodiversity and advocate a more integrated approach. Ecologists need to recognize that wildlife-friendly farming is not the only land-use strategy that can be used to conserve biodiversity and to research alternative options such as land sparing. There is also a need for social scientists and ecologists to bring their approaches together, so that land-use change and its consequences can be investigated in a more holistic way.

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The complex and variable composition of natural sediments makes it very difficult to predict the bioavailability and bioaccumulation of sediment-bound contaminants. Several approaches have been proposed to overcome this problem, including an experimental model using artificial particles with or without humic acids as a source of organic matter. For this work, we have applied this experimental model, and also a sample of a natural sediment, to investigate the uptake and bioaccumulation of 2,4-dichlorophenol (2,4-DCP) by Sphaerium corneum. Additionally, the particle-water partition coefficients (K-d) were calculated. The results showed that the bioaccumulation of 2,4-DCP by clams did not depend solely on the levels of chemical dissolved, but also on the amount sorbed onto the particles and the characteristics and the strength of that binding. This study confirms the value of using artificial particles as a suitable experimental model for assessing the fate of sediment-bound contaminants. (c) 2006 Elsevier Ltd. All rights reserved.

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Chemistry of reactive nitrogen oxides, NOy, is crucial for our understanding of composition and properties of the Earth’s atmosphere. The proof-of-principle experiments demonstrated that we are able to study the atmospheric fate of nitrogen oxides that has significant impact on global climate and hydrological cycle, thus affecting the likelihood of local floods and acid rain.

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Through increases in net primary production (NPP), elevated CO2 is hypothesizes to increase the amount of plant litter entering the soil. The fate of this extra carbon on the forest floor or in mineral soil is currently not clear. Moreover, increased rates of NPP can be maintained only if forests can escape nitrogen limitation. In a Free atmospheric CO2 Enrichment (FACE) experiment near Bangor, Wales, 4 ambient CO2 and 4 FACE plots were planted with patches of Betula pendula, Alnus glutinosa and Fagus sylvatica on a former arable field. Four years after establishment, only a shallow L forest floor litter layer had formed due to intensive bioturbation. Total soil C and N contents increased irrespective of treatment and species as a result of afforestation. We could not detect an additional C sink in the soil, nor were soil C stabilization processes affected by FACE. We observed a decrease of leaf N content in Betula and Alnus under FACE, while the soil C/N ratio decreased regardless of CO2 treatment. The ratio of N taken up from the soil and by N2-fixation in Alnus was not affected by FACE. We infer that increased nitrogen use efficiency is the mechanism by which increased NPP is sustained under elevated CO2 at this site.

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We describe a polymerase chain reaction which amplifies part of the Eco RI repeat unit of the fowl W chromosome. The resulting 447 bp fragment enables DNA from female birds to be identified. The composition of this DNA is confirmed by a nested polymerase chain reaction which specifically amplifies a known internal 263 bp region in this fragment. Using this technique it is possible to follow the fate of female cells in male germline chimaeras. The polymerase chain reaction fragment can be traced in cells of the embryonic and hatchling gonad and in adult sperm implying that cells containing the W chromosome are capable of being processed through the avian testis.

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Since the conclusion of its 14-year civil war in 2003, Liberia has struggled economically. Jobs are in short supply and operational infrastructural services, such as electricity and running water, are virtually nonexistent. The situation has proved especially challenging for the scores of people who fled the country in the 1990s to escape the violence and who have since returned to re-enter their lives. With few economic prospects on hand, many have elected to enter the artisanal diamond mining sector, which has earned notoriety for perpetuating the country's civil war. This article critically reflects on the fate of these Liberians, many of whom, because of a lack of government support, finances, manpower and technological resources, have forged deals with hired labourers to work artisanal diamond fields. Specifically, in exchange for meals containing locally grown rice and a Maggi (soup) cube, hired hands mine diamondiferous territories, splitting the revenues accrued from the sales of recovered stones amongst themselves and the individual ‘claimholder’ who hired them. Although this cycle—referred to here as ‘diamond mining, rice farming and a Maggi cube’—helps to buffer against poverty, few of the parties involved will ever progress beyond a subsistence level

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Limb girdle muscular dystrophy type 2H (LGMD2H) is an inherited autosomal recessive disease of skeletal muscle caused by a mutation in the TRIM32 gene. Currently its pathogenesis is entirely unclear. Typically the regeneration process of adult skeletal muscle during growth or following injury is controlled by a tissue specific stem cell population termed satellite cells. Given that TRIM32 regulates the fate of mammalian neural progenitor cells through controlling their differentiation, we asked whether TRIM32 could also be essential for the regulation of myogenic stem cells. Here we demonstrate for the first time that TRIM32 is expressed in the skeletal muscle stem cell lineage of adult mice, and that in the absence of TRIM32, myogenic differentiation is disrupted. Moreover, we show that the ubiquitin ligase TRIM32 controls this process through the regulation of c-Myc, a similar mechanism to that previously observed in neural progenitors. Importantly we show that loss of TRIM32 function induces a LGMD2H-like phenotype and strongly affects muscle regeneration in vivo. Our studies implicate that the loss of TRIM32 results in dysfunctional muscle stem cells which could contribute to the development of LGMD2H.