7,783 research outputs found

    Change in the North Atlantic circulation associated with the mid-Pleistocene transition

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    The southwestern Iberian margin is highly sensitive to changes in the distribution of North Atlantic currents and to the position of oceanic fronts. In this work, the evolution of oceanographic parameters from 812 to 530 ka (MIS20-MIS14) is studied based on the analysis of planktonic foraminifer assemblages from site IODP-U1385 (37 degrees 34.285' N, 10 degrees 7.562' W; 2585m b.s.l.). By comparing the obtained results with published records from other North Atlantic sites between 41 and 55 degrees N, basin-wide paleoceano-graphic conditions are reconstructed. Variations of assemblages dwelling in different water masses indicate a major change in the general North Atlantic circulation during MIS16, coinciding with the definite establishment of the 100 ky cyclicity associated with the mid-Pleistocene transition. At the surface, this change consisted in the redistribution of water masses, with the subsequent thermal variation, and occurred linked to the northwestward migration of the Arctic Front (AF), and the increase in the North Atlantic Deep Water (NADW) formation with respect to previous glacials. During glacials prior to MIS16, the NADW formation was very weak, which drastically slowed down the surface circulation; the AF was at a southerly position and the North Atlantic Current (NAC) diverted southeastwards, developing steep south-north, and east-west, thermal gradients and blocking the arrival of warm water, with associated moisture, to high latitudes. During MIS16, the increase in the meridional overturning circulation, in combination with the northwestward AF shift, allowed the arrival of the NAC to subpolar latitudes, multiplying the moisture availability for ice-sheet growth, which could have worked as a positive feedback to prolong the glacials towards 100 ky cycles.info:eu-repo/semantics/publishedVersio

    What is the impact of educational systems on social mobility across Europe? A comparative approach

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    Education is reasonably expected to enhance intergenerational social mobility. However, the extent to which educational systems foster or otherwise constrain social mobility remains controversial. In this paper, data from the European Social Survey covering 22 countries is analysed in order to assess social mobility in the second half of the 20th Century. Variation across five cohesive regional clusters is examined in detail. Results confirm increasing rates of social mobility in Europe and their close relation to massive structural shifts. The erosion of the education-occupation linkage presents a current threat to this trend. Considering formal credentials only, the most equalitarian educational systems are to be found in the United Kingdom and Ireland, but their ability to allocate individuals in the occupational structure is lower than in the other regions. Scandinavian systems show higher chances of social mobility through education, while Mediterranean systems present lower fluidity rates in both the background-education link (like Eastern European countries) and the education-occupation link (like the UK & Ireland). Gender and migration are identified as key factors to explain these differences.Há razões para esperar que a educação promova a mobilidade social intergeracional. Porém, a competência dos sistemas educativos para alimentar ou, pelo contrário, limitar a mobilidade social continua a ser motivo de controvérsia. Neste texto, analisam-se dados do European Social Survey relativos a 22 países com o intuito de aferir os padrões de mobilidade social na segunda metade do século XX. A variação entre cinco grupos regionais coesos merece particular atenção. Os resultados confirmam as taxas crescentes de mobilidade social na Europa e a sua relação estreita com transformações estruturais massivas. Uma ameaça actual a esta tendência é constituída pelo enfraquecimento da relação educação-ocupação. Considerando apenas qualificações formais, os sistemas educativos mais igualitários encontram-se no Reino Unido e na Irlanda, mas a sua capacidade para colocar indivíduos na estrutura ocupacional é menor do que noutras regiões. Os sistemas escandinavos apresentam probabilidades mais elevadas de mobilidade social através da educação, enquanto os sistemas mediterrânicos têm taxas menores de fluidez quer na relação origem-educação (como os países da Europa de Leste), quer na relação educação-ocupação (como o Reino Unido e a Irlanda). Género e migração são identificados como factores fundamentais para entender estas diferenças

    Morphology, biostratigraphy, and evolution of PliocenePleistocene diatoms Proboscia barboi..

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    Proboscia barboi and Proboscia curvirostris are two important diatom biostratigraphic markers from the high latitudes of the North Pacific and North Atlantic Oceans, dating back to the Pliocene-Pleistocene time. This study analyzes the biostratigraphic events and describes the morphology of P. barboi and P. curvirostris, particularly the morphologic variations of the latter species, based on observations of samples of Core U1340A from the IODP Expedition 323 in the Bering Sea. In Site U1340, the First Occurrence of P. curvirostris is observed at 1.52Ma and its First Common Occurrence at 1.39Ma, where morphologic variations were found abundantly. The Last Occurrence of P. curvirostris was found at 0.33Ma, while P. barboi's Last Occurrence is found at 0.67Ma. Based on the morphological similarity and known biostratigraphic distribution, previous authors have assumed that P. curvirostris descends from P. barboi, although this hypothesis is still in debate. At 1.39Ma P. curvirostris shows an increased size and thickness, which is typical of P. barboi, and some specimens display an incipient structure characteristic of P. curvirostris - the secondary spine. This morphology is intermediate between the two species and suggests an evolutionary transition from P. barboi to P. curvirostris. However, P. curvirostris already existed since 1.9Ma in the subarctic indicating that its speciation happened much earlier than 1.39Ma. Furthermore, since P. barboi co-occurs with P. curvirostris in the North Pacific, this evolutionary process was cladogenetic. Besides being evidence for a phylogenetic relationship, the abundant occurrence of intermediate forms at 1.39Ma may constitute a bioevent for a short time interval in the Bering Sea.info:eu-repo/semantics/publishedVersio

    Moeda universal

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    Através de um só lançamento de uma moeda equilibrada, podemos realizar uma escolha aleatória com dois resultados possíveis e equiprováveis. Neste texto é apresentado um algoritmo que generaliza este procedimento para o caso em que os dois resultados possíveis têm probabilidades quaisquer p e q, p+q=1. Designamos o algoritmo por Moeda Universal. A sua execução procede por sucessivos lançamentos de uma moeda equilibrada, com a particularidade de o número de lançamentos necessários para efectuar a escolha ser independente das probabilidades envolvidas, o que confere ao algoritmo uma certa naturalidade enquanto generalização do processo de escolha com dois resultados possíveis equiprováveis, que requer sempre um só lançamento

    Interpenetration of Vibrating Thresholds:Eroticism, Sound and Sensorial Intimacy

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    Sound allows for multiple crossings between the sensorial and the sensual. To auscultate (‘to listen attentively’) resonates with the near homophonous osculate (from the Latin osculatus, meaning ‘to kiss’, and osculum, ‘little mouth’). Each ear, a hole surrounded by a textured chalice of skin and cartilage, leading through to a thin, taut and highly sensitive piece of skin – the tympanic membrane. Beyond that, a tunnel, a bony labyrinth leading to a fluid-filled spiral, the cochlea, where vibration becomes neural transmission. Every sound, a thread of Ariadne. When 19th-century sonic technology focussed upon the ear, the erotic was duly invoked. The stethoscope, the telegraph and the telephone, all manifested different potentialities in engaging with the aural dynamics of eroticism. In 2018, the siren’s call is an ASMR binaural murmur. Immersive sound meant to be experienced as pleasurable touch, a wave of tingling joy radiating from the scalp, down the neck and into the upper spine, activating the envelope of the skin. Pornography has likewise updated its tools. VR sound has reconfigured the potential of the first-person view subgenre, introducing variations of proximity and acoustic field envelopment in the old orgasmic tropes. This article aims to explore some of the contemporary erotic uses of mediated sound, not only in terms of their technological genealogy, but trying to sketch a conceptual map in order to investigate their nature and impact on everyday embodied experiences of sonic immersion. It focusses on the kinaesthetic dynamics of sound experienced as tactility and operating radical permeability, penetrating bodies and redefining interpersonal territories

    Towards a new relation with education and work? Youth transitions in Europe and in Latin America

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    This paper discusses the current experiences of young people both in the educational systems and in the labor market, tracking the objective and subjective relations between both social fields. Based on different statistical sources, major trends in Europe and in Latin America are compared, in order to sketch some global tendencies but also regional paths. The main argument is that, even if uncertainty, non-linearity and individualization are increasing worldwide, actually the European youth and the Latin American one face diverging risks and opportunities, due to unequal economic structures and cultural frames, as well as recent political orientations.Neste artigo discutimos as actuais experiências dos jovens tanto no sistema de ensino como no mercado de trabalho, procurando captar as relações objectivas e subjectivas entre esses dois campos sociais. Com base em diversas fontes estatísticas, comparamos as principais tendências na Europa e na América Latina, com vista a traçar algumas tendências globais, mas também diferenças regionais. O nosso principal argumento é que, se bem que a incerteza, o carácter não linear e a individualização das carreiras se acentuam em todo o mundo, actualmente a juventude enfrenta riscos e oportunidades diferentes na Europa e na América Latina, devido a diferenças substanciais nas estruturas económicas e quadros culturais, bem como a orientações políticas recentes

    Estudo térmico de um edifício escolar com topologia complexa

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    Dissertação de mest., Engenharia do Ambiente (Energias Renováveis), Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2011Neste trabalho pretende-se efectuar uma avaliação numérica, recorrendo ao Multi-node Building Thermal Behavior (MNBTB), das condições de conforto térmico e temperatura num edifício de tipologia complexa. Trata-se do edifício da Faculdade de Economia (FE) e da Faculdade de Ciências e Tecnologia (FCT), antiga Faculdade de Engenharia e Recursos Naturais (FERN) na Universidade do Algarve (UAlg) no Campus de Gambelas. Um edifício que se encontra na plenitude das suas funções. Pretende-se com este trabalho efectuar uma avaliação das condições de conforto térmico e da temperatura do ar interior, tanto para as condições de Inverno, como de Verão. Após a simulação, de acordo com os resultados numéricos obtidos, procede-se à sua análise de modo a identificar debilidades e carências. Uma das conclusões a que se chega é a importância do sombreamento a Sul do complexo recorrendo a estruturas externas e envolventes, ao qual se verificou que o modelo numérico simula com aproximações muito boas o comportamento da evolução da temperatura nos compartimentos. As estruturas externas que se propõe são árvores de grande porte a Sul do estabelecimento, de modo a proteger/resguardar os espaços mais problemáticos. Em trabalhos futuros dever-se-á ter em conta a ocupação de cada divisão de maneira aferir necessidades de ventilação para melhoria da QAI, bem como efectuar novas simulações considerando as lamelas existentes
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