174 resultados para refugia


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Global climate changes during the Quaternary reveal much about broader evolutionary effects of environmental change. Detailed regional studies reveal how evolutionary lineages and novel communities and ecosystems, emerge through glacial bottlenecks or from refugia. There have been significant advances in benthic imaging and dating, particularly with respect to the movements of the British (Scottish) and Irish ice sheets and associated changes in sea level during and after the Last Glacial Maximum (LGM). Ireland has been isolated as an island for approximately twice as long as Britain with no evidence of any substantial, enduring land bridge between these islands after ca 15 kya. Recent biogeographical studies show that Britain's mammal community is akin to those of southern parts of Scandinavia, The Netherlands and Belgium, but the much lower mammal species richness of Ireland is unique and needs explanation. Here, we consider physiographic, archaeological, phylogeographical i.e. molecular genetic, and biological evidence comprising ecological, behavioural and morphological data, to review how mammal species recolonized western Europe after the LGM with emphasis on Britain and, in particular, Ireland. We focus on why these close neighbours had such different mammal fauna in the early Holocene, the stability of ecosystems after LGM subject to climate change and later species introductions.

There is general concordance of archaeological and molecular genetic evidence where data allow some insight into history after the LGM. Phylogeography reveals the process of recolonization, e.g. with respect to source of colonizers and anthropogenic influence, whilst archaeological data reveal timing more precisely through carbon dating and stratigraphy. More representative samples and improved calibration of the ‘molecular clock’ will lead to further insights with regards to the influence of successive glaciations. Species showing greatest morphological, behavioural and ecological divergence in Ireland in comparison to Britain and continental Europe, were also those which arrived in Ireland very early in the Holocene either with or without the assistance of people. Cold tolerant mammal species recolonized quickly after LGM but disappeared, potentially as a result of a short period of rapid warming. Other early arrivals were less cold tolerant and succumbed to the colder conditions during the Younger Dryas or shortly after the start of the Holocene (11.5 kya), or the area of suitable habitat was insufficient to sustain a viable population especially in larger species. Late Pleistocene mammals in Ireland were restricted to those able to colonize up to ca 15 kya, probably originating from adjacent areas of unglaciated Britain and land now below sea level, to the south and west (of Ireland). These few, early colonizers retain genetic diversity which dates from before the LGM. Late Pleistocene Ireland, therefore, had a much depleted complement of mammal species in comparison to Britain.

Mammal species, colonising predominantly from southeast and east Europe occupied west Europe only as far as Britain between ca 15 and 8 kya, were excluded from Ireland by the Irish and Celtic Seas. Smaller species in particular failed to colonise Ireland. Britain being isolated as an island from ca. 8 kya has similar species richness and composition to adjacent lowland areas of northwest continental Europe and its mammals almost all show strongest genetic affinity to populations in neighbouring continental Europe with a few retaining genotypes associated with earlier, western lineages.

The role of people in the deliberate introduction of mammal species and distinct genotypes is much more significant with regards to Ireland than Britain reflecting the larger species richness of the latter and its more enduring land link with continental Europe. The prime motivation of early people in moving mammals was likely to be resource driven but also potentially cultural; as elsewhere, people exploring uninhabited places introduced species for food and the materials they required to survive. It is possible that the process of introduction of mammals to Ireland commenced during the Mesolithic and accelerated with Neolithic people. Irish populations of these long established, introduced species show some unique genetic variation whilst retaining traces of their origins principally from Britain but in some cases, Scandinavia and Iberia. It is of particular interest that they may retain genetic forms now absent from their source populations. Further species introductions, during the Bronze and late Iron Ages, and Viking and Norman invasions, follow the same pattern but lack the time for genetic divergence from their source populations. Accidental introductions of commensal species show considerable genetic diversity based on numerous translocations along the eastern Atlantic coastline. More recent accidental and deliberate introductions are characterised by a lack of genetic diversity other than that explicable by more than one introduction.

The substantial advances in understanding the postglacial origins and genetic diversity of British and Irish mammals, the role of early people in species translocations, and determination of species that are more recently introduced, should inform policy decisions with regards to species and genetic conservation. Conservation should prioritise early, naturally recolonizing species and those brought in by early people reflecting their long association with these islands. These early arrivals in Britain and Ireland and associated islands show genetic diversity that may be of value in mitigating anthropogenic climate change across Europe. In contrast, more recent introductions are likely to disturb ecosystems greatly, lead to loss of diversity and should be controlled. This challenge is more severe in Ireland where the number and proportion of invasive species from the 19th century to the present has been greater than in Britain.

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The disjunct distributions of the Lusitanian flora, which are found only in south-west Ireland and northern Iberia, and are generally absent from intervening regions, have been of great interest to biogeographers. There has been much debate as to whether Irish populations represent relicts that survived the Last Glacial Maximum (LGM; approximately 21 kya), or whether they recolonized from southern refugia subsequent to the retreat of the ice and, if so, whether this occurred directly (i.e. the result of long distance dispersal) or successively (i.e. in the manner of a ‘steeplechase’, with the English Channel and Irish Sea representing successive ‘water-jumps’ that have to be successfully crossed). In the present study, we used a combined palaeodistribution modelling and phylogeographical approach to determine the glacial history of the Irish spurge, Euphorbia hyberna, the sole member of the Lusitanian flora that is also considered to occur naturally in south-western England. Our findings suggest that the species persisted through the LGM in several southern refugia, and that northern populations are the result of successive recolonization of Britain and Ireland during the postglacial Littletonian warm stage, akin to the ‘steeplechase’ hypothesis.

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Despite recent advances in the understanding of the interplay between a dynamic physical environment and phylogeography in Europe, the origins of contemporary Irish biota remain uncertain. Current thinking is that Ireland was colonized post-glacially from southern European refugia, following the end of the last glacial maximum(LGM), some 20 000 years BP. The Leisler’s bat (Nyctalus leisleri), one of the few native Irish mammal species, is widely distributed throughout Europe but, with the exception of Ireland, is generally rare and considered vulnerable. We investigate the origins and phylogeographic relationships of Irish populations in relation to those across Europe, including the closely related species N. azoreum. We use a combination of approaches, including mitochondrial and nuclear DNA markers, in addition to approximate Bayesian computation and palaeo-climatic species distribution modelling. Molecular analyses revealed two distinct and diverse European mitochondrialDNAlineages,which probably diverged in separate glacial refugia. Awestern lineage, restricted to Ireland, Britain and the Azores, comprises Irish and British N. leisleri and N. azoreum specimens; an eastern lineage is distributed throughout mainland Europe. Palaeo-climatic projections indicate suitable habitats during the LGM, including known glacial refugia, in addition to potential novel cryptic refugia along the western fringe of Europe. These results may be applicable to populations of many species.

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O nosso estudo incide, primordialmente, sobre as polémicas de carácter político e consequentes acusações de que Louis-Ferdinand Céline foi – e continua a ser – alvo. Tais aspectos conduzem-nos a questionar, com alguma veemência e perplexidade, as razões da sua fuga através da Alemanha, bem como as relações que estabeleceu com os Nazis durante a segunda guerra mundial. Num primeiro momento, elaborámos uma contextualização de cariz temporal e factual, tentando perceber – quiçá explicar -, o sentido das posições assumidas por Céline aquando da composição dos seus pamphlets, marcada por uma reivindicação violenta do seu antisemitismo e que surge, omnipresente, sob forma de cartas, entrevistas e outros escritos. Contudo, a essência do nosso trabalho consistiu numa análise detalhada das diferentes etapas dos anos de exílio do escritor, primeiro numa Alemanha devastada pela guerra, onde se refugia a partir de 17 de Junho de 1944 e mais tarde, na Dinamarca (1945-1951), de onde terá de responder às acusações de traição que lhe são dirigidas pela justiça francesa, antes de um regresso sem glória, a França, e de uma reabilitação tardia e titubeante. Os escritos que constituem o corpus do nosso trabalho traduzem, de modo inequívoco, a experiência amarga e cruel dos anos de exílio e da lembrança feita de dor e ódio, que o escritor sentiu profundamente, como um espinho na própria carne. Apesar do caminho tortuoso, que lhe confere uma aura de escritor “maldito”, Céline permanece, ainda hoje, como um dos maiores génios da literatura francesa do século XX.

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Dissertação de mest., Biologia Marinha, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2008

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The fire salamander complex is quite diverse in the Iberian Peninsula where nine subspecies of Salamandra salamandra are currently recognized. Here, we analysed the geographical distribution of the subspecies S. s. gallaica and S. s. crespoi using partial sequences of the mitochondrial cytochrome b gene of 168 individuals from 12 locations in Portugal. Our results support the existence of a deep lineage divergence between the two subspecies, with non-overlapping geographical distributions except in two contact zones: one in Sesimbra on the western coast, and another in Alcoutim on the southeastern border with Spain. Moreover, S. s. crespoi displays signs of gene flow among the sampled locations whereas S. s. gallaica shows evidence of some restriction to gene flow. Present-day genetic make-up of S. s. gallaica and S. s. crespoi is a result of past historical events, fine-tuned by contemporary Iberian geoclimate. Humid mountain areas were found to harbour increased genetic diversity possibly acting as past refugia during drier interglacial periods. To analyse wider geographical patterns and lineage splitting events within S. salamandra we performed a Bayesian dating analysis completing our data set with previously published sequences. The observed divergences were associated to successive biogeographic scenarios, and to other Iberian species showing similar trends.

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This thesis revealed the most importance factors shaping the distribution, abundance and genetic diversity of four marine foundation species. Environmental conditions, particularly sea temperatures, nutrient availability and ocean waves, played a primary role in shaping the spatial distribution and abundance of populations, acting on scales varying from tens of meters to hundreds of kilometres. Furthermore, the use of Species Distribution Models (SDMs) with biological records of occurrence and high-resolution oceanographic data, allowed predicting species distributions across time. This approach highlighted the role of climate change, particularly when extreme temperatures prevailed during glacial and interglacial periods. These results, when combined with mtDNA and microsatellite genetic variation of populations allowed inferring for the influence of past range dynamics in the genetic diversity and structure of populations. For instance, the Last Glacial Maximum produced important shifts in species ranges, leaving obvious signatures of higher genetic diversities in regions where populations persisted (i.e., refugia). However, it was found that a species’ genetic pool is shaped by regions of persistence, adjacent to others experiencing expansions and contractions. Contradicting expectations, refugia seem to play a minor role on the re(colonization) process of previously eroded populations. In addition, the available habitat area for expanding populations and the inherent mechanisms of species dispersal in occupying available habitats were also found to be fundamental in shaping the distributions of genetic diversity. However, results suggest that the high levels of genetic diversity in some populations do not rule out that they may have experienced strong genetic erosion in the past, a process here named shifting genetic baselines. Furthermore, this thesis predicted an ongoing retraction at the rear edges and extinctions of unique genetic lineages, which will impoverish the global gene pool, strongly shifting the genetic baselines in the future.

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Tese de doutoramento, Biologia (Biologia da Conservação), Universidade de Lisboa, Faculdade de Ciências, 2014

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Tese de doutoramento (co-tutela), Biologia (Biologia da Conservação), Faculdade de Ciências da Universidade de Lisboa, University of East Anglia, School of Environmental Sciences, 2014

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Thesis (Master's)--University of Washington, 2013

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La tragi-comédie de Corneille, «Le Cid» (1636-7), est davantage une pièce d‘amour qui illustre bien la condition de la femme au XVIIème siècle. Le triangle amoureux constitué par l‘Infante, Chimène et Rodrigue est l‘un des fondements de la pièce. Cependant, comme les personnages sont insérés dans un système féodal basé sur une idéologie aristocratique, l‘amour ne se présente pas comme une jouissance paisible. De cette façon, il y a une lutte acharnée entre l‘amour, le devoir et l‘honneur, ce qui est frappant au niveau lexical. Les personnages les plus jeunes utilisent beaucoup de mots associés au thème de l‘amour et qui ont le radical amour-, tandis que les plus âgés emploient très souvent des mots qui appartiennent au champ lexical de l‘honneur et de la gloire. Selon D. Diègue, l‘honneur a plus de puissance que l‘amour, et il trouve que l‘homme qui s‘endort dans l‘amour oublie ses devoirs. Pour l‘Infante, Chimène et Rodrigue, l‘amour est lié à la souffrance. L‘Infante souffre, mais elle se conforme, parce qu‘étant donné qu‘elle est fille de roi, elle ne peut pas aimer Rodrigue qui appartient à un rang inférieur. Chimène est le revers de l‘Infante, c‘est une femme rebelle qui veut mouler sa destinée. Cependant, tout au long de la pièce, l‘héroïne est assujettie à une force mâle: si parfois l‘amour entre elle et Rodrigue ressemble à l‘amour courtois du Moyen âge quand il se met à la disposition de sa maîtresse et la place au-dessus de lui, la plupart du temps il met la passion en dessous de l‘honneur, parce que c‘est un homme et descend d‘une famille de guerriers vaillants. Selon le code chevaleresque dans lequel il est inséré la femme est inférieure à l‘homme. À la fin de la pièce, il y a une victoire de l‘amour sur l‘honneur et le devoir : Chimène abdique de son honneur en pardonnant et en prenant pour mari l‘assassin de son père. Le monde de l‘élément masculin triomphe et elle devient le prix de la victoire de Rodrigue. Mais si son statut de femme l‘empêche de sortir victorieuse, elle ne se conforme pas et dans sa dernière tirade elle met en question la justice et défie la société féodale.

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The genetic diversity of populations, which contributes greatly to their adaptive potential, is negatively affected by anthropogenic habitat fragmentation and destruction. However, continental-scale losses of genetic diversity also resulted from the population expansions that followed the end of the last glaciation, an element that is rarely considered in a conservation context. We addressed this issue in a meta-analysis in which we compared the spatial patterns of vulnerability of 18 widespread European amphibians in light of phylogeographic histories (glacial refugia and postglacial routes) and anthropogenic disturbances. Conservation statuses significantly worsened with distances from refugia, particularly in the context of industrial agriculture; human population density also had a negative effect. These findings suggest that features associated with the loss of genetic diversity in post-glacial amphibian populations (such as enhanced fixation load or depressed adaptive potential) may increase their susceptibility to current threats (e.g., habitat fragmentation and pesticide use). We propose that the phylogeographic status of populations (i.e., refugial vs. post-glacial) should be considered in conservation assessments for regional and national red lists.

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Conocer la demanda universitaria de universitarios existente en Asturias durante el año 1985, la oferta de titulados universitarios en Asturias en el mismo año, así como las previsiones a medio plazo. Proponer algunas vías de ajuste entre dicha demanda y oferta. Constituida por 1215 anuncios localizados en diversas fuentes de información. Respecto a la demanda se analizaron las siguientes variables:.. Oficiales: Boletín del Estado, Boletín Oficial de la Autonomía. Habituales o periódicas: 'La Nueva España', 'La Voz de Asturias', 'El Comercio'. Otras: Colegios profesionales, Instituto Nacional de Empleo, Centro de Orientación e Información al Estudiante de la Universidad de Oviedo. Para la recogida de información en estas fuentes se estableció un cuestionario en el que se especificaban los ítems de interés. La demanda tiene su origen fundamentalmente en la Administración, lo que es preocupante pues en su mayoría responden a una necesidad coyuntural de las Administraciones locales y autonómicas, por lo cual es previsible una saturación de las mismas. La oferta universitaria en Asturias es grande y diversificada, por lo que sería necesario un acercamiento de la universidad a la empresa. Existe un claro exceso de oferta frente a la demanda detectada, tanto en términos generales como por especialidades. Una buena parte de la oferta se refugia en el subempleo, o estudia desde el subempleo. Un sector importante de la oferta esta abocado al paro. Parece perfilarse la existencia de familias ocupacionales: ramas humanísticas, empresariales, ramas biomédicas, etc. Aunque tradicionalmente es la Administración Pública la que absorbe a la mayoría de los universitarios, parece que esta situación tenderá a disminuir y que se producirá un importante desplazamiento de mano de obra titulada hacia la empresa privada, así como una tendencia marcada al autoempleo, siendo esto lo que más posibilidades ofrece. Los campos de actividad con más futuro serán los que se sitúen en el ámbito de las transformaciones tecnológicas: electrónica, nuevas energías bioenergéticas, etc. Fuentes de información, sectores de actividad que demandan, funciones que se demandan, títulos demandados, niveles educativos demandados, áreas que promueven la demanda, edad demandada, sexo demandado, experiencia, idiomas exigidos, requisitos estipulados, tipo y duración del contrato, etc. Respecto a la oferta educativa se analizan las variables: volumen de matrícula, especialidades de la oferta educativa, distribución de la matrícula por especialidades y cursos previsión del número de matriculados, expectativas de graduados, universitarios subempleados, demandas de empleo de los universitarios.

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Resumen basado en el de la autora

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Estudiar los factores socioambientales que influyen en la delincuencia. Ofrece una definición de delincuencia y marginación, expone los factores socioambientales que influyen en ambas, analiza sus manifestaciones e informa sobre su prevención, explica el caso del delincuente deficiente y propone unas soluciones para la delincuencia. 1) La sociedad urbana, más que la rural, favorece la ambición. Está dominada por las pautas de adquisición o del logro, lo que activa la inclinación delictiva al aparecer la frustración, y dicha inclinación es incrementada por la despersonalización de las relaciones que se dan en la urbe, la división del trabajo y una solidaridad más elástica, la cual es producto de la diferenciación de funciones, en el ambiente competitivo en que discurre su actividad. 2) Los sistemas de estratificación conocidos se basan fundamentalmente en el mantenimiento de ciertos grados de desigualdad dados en una relación dialéctica de una sociedad dividida en dominados y dominantes que llevan a una distribución desigual de los bienes, poder y reconocimiento social. Por lo cual se comprende que sean las clases más oprimidas las más inclinadas al delito, ya que por definición disponen de menos recursos para la consecución de sus fines. 3) La pobreza, en el sentido de carencia de elementos básicos, ha sido uno de los factores que más ha influido en la delincuencia juvenil, sobre todo en lugares de presión ambiental y económica. 4) La escuela es otra vía de marginación, puesto que un estatus intelectual bajo influye en una actitud negativa hacia la escuela y conlleva a una conducta agresiva y a una búsqueda de sensaciones fuertes, las cuales se consiguen por medio de amigos delincuentes. El chico ante su fracaso educativo trata de quitar importancia a la escuela y de afirmar sus propios valores, aunque sea a través de actos delictivos. 5) El delincuente se refugia en las bandas porque dentro de su hogar se siente rechazado, entonces en su interior se crea un resentimiento contra la sociedad por no haberle dado lo que el consideraba justo y necesario, y por ello se agrupa con otros individuos que consideran a la sociedad como su enemiga. 1) Las causas y los factores de la inadaptación es lo que debe preocupar al Estado y no la apreciación de su responsabilidad. Ha de ser el Estado, quien en la perspectiva de la justicia y la obligatoriedad social, debe satisfacer la educación de los niños inadaptados. 2) Tanto la enseñanza como el marco formativo general, deben propiciar la actividad, el diálogo, la responsabilidad y la congestión de todas las actividades en el marco de una concepción teóricamente no directiva sino de orientación comunitaria, con la creación de grupos reducidos de acción terapéutica que favorezcan un trato más individualizado, familiar y afectivo. 3) La familia también debe ayudar al delincuente, tiene que estar a su lado, ayudarle, protegerle, evitando que el se abandone por insolidaridad.