1,781 research outputs found

    Four Blue Beads from Gardom's Edge

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    Four blue glass beads from the prehistoric site of Gardom’s Edge, in the upland area of the Peak District in Britain, were analyzed to determine their composition, date, and origin. The simple annular beads were of unknown date, although they were recovered from contexts that were either Bronze Age or Iron Age in date. The compositions of the beads are relatively unusual. They were manufactured with mineral alkalis, but they contained extremely low concentrations of impurities and were colored with copper. Comparison with other recently analyzed glasses shows (rare) parallels in Europe of Iron Age date, but not in the eastern Mediterranean (Egypt, Near East), which suggests an origin somewhere in the west. This is an extraordinary find in a marginal area, which suggests far-reaching trade and exchange networks

    Uniqueness of Ground States for Short-Range Spin Glasses in the Half-Plane

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    We consider the Edwards-Anderson Ising spin glass model on the half-plane Z×Z+Z \times Z^+ with zero external field and a wide range of choices, including mean zero Gaussian, for the common distribution of the collection J of i.i.d. nearest neighbor couplings. The infinite-volume joint distribution K(J,α)K(J,\alpha) of couplings J and ground state pairs α\alpha with periodic (respectively, free) boundary conditions in the horizontal (respectively, vertical) coordinate is shown to exist without need for subsequence limits. Our main result is that for almost every J, the conditional distribution K(αJ)K(\alpha|J) is supported on a single ground state pair.Comment: 20 pages, 3 figure

    Re-used Roman rubbish: a thousand years of recycling glass

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    The suitability of glass for re-melting and recycling was widely exploited in the past. This paper reviews the evidence, particularly for the 1st millennium AD, using examples from Western Europe. For much of this period glass was produced on a large-scale at a relatively small number of specialised glassmaking sites, which supplied numerous dispersed workshops where glass was modified and shaped. This is only part of the picture however, because the glassmakers, glassworkers and consumers were also linked by a complex, interdependent cycle of supply, use, discard, salvage and re-use, making recycling an essential part of interpreting archaeological glass

    Mountain maidens and cowgirls: Exercise, athleticism, and ideological constraints for several Scott heroines

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    This chapter addresses the way Scott presents competence in space-conquering activities in three heroines across his career: from Ellen Douglas rowing in The Lady of the Lake, Jeanie Deans walking in The Heart of Mid-Lothian, and Anne of Geierstein mountaineering. Scott converts them into activities for the specular gaze of the reader. The Lady of the Lake provides Scott's first athletic heroine, but also hedging devices to reassure his readers that the piquant spectacle she offers can be an image of desirable femininity. Ellen's powers are assimilated to a mixture of classical and romance models suggesting the otherworldly, as a mode of containing the implications of female bodily competence. Once there, Ellen, the 'mountain-maiden' still holds the secret of the path that leads to what Scott's note calls a 'place of retreat for the hour of necessity' but what the poem, calls a 'rustic bower' and 'an enchanted hall'

    Coin Tossing as a Billiard Problem

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    We demonstrate that the free motion of any two-dimensional rigid body colliding elastically with two parallel, flat walls is equivalent to a billiard system. Using this equivalence, we analyze the integrable and chaotic properties of this new class of billiards. This provides a demonstration that coin tossing, the prototypical example of an independent random process, is a completely chaotic (Bernoulli) problem. The related question of which billiard geometries can be represented as rigid body systems is examined.Comment: 16 pages, LaTe

    A prova de exercício cárdio-pulmonar e o prognóstico cirúrgico do cancro do pulmão

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    Resumo: Os autores procuram dar mais um contributo para a avaliação pré-operatória dos doentes com carcinoma de não pequenas células que vão ser sujeitos a cirurgia de ressecção pulmonar.Trata-se de um estudo prospectivo onde foi avaliado o resultado da cirurgia em termos de complicações ocorridas nos 30 dias a seguir à operação. Os autores definiram cada uma das complicações (óbito, enfarte do miocárdio, insuficiências respiratória, cardíaca e renal, embolia pulmonar, pneumonia e septicemia) e ainda analisaram 3 dessas complicações em separado (óbito, enfarte do miocárdio e insuficiência respiratória), as quais designaram por âfraco resultadoâ.Antes da cirurgia, foram avaliados 99 doentes (34 pneumectomias, 56 lobectomias, 6 bilobectomias e 3 ressecções atípicas) com espirometria (FEV1 em litros) e consumo de oxigénio no exercício máximo (VO2peak). Só 26 doentes tinham valores funcionais considerados borderline (FEV1 < 1,5 litros para lobectomia e < 2,0 litros para pneumectomia). Nos resultados apresentados observámos os seguintes valores médios: FEV1=2,06 litros; FEV1=80,4% do valor teórico; VO2peak=18,8 ml/kg/min ou 88,3% do valor teórico. Só existiram 4 óbitos (4%) e 21 doentes tiveram uma ou mais das complicações referenciadas.Os autores não encontraram relação significativa entre as complicações pós-operatórias e o FEV1 em litros. Verificaram ainda que o VO2peak em percentagem do valor teórico previa melhor um âfraco resultadoâ do que o mesmo parâmetro em valor absoluto.Em relação aos óbitos, um dos doentes tinha sido submetido a quimioterapia, o que dificultou a avaliação do desfecho. Nos restantes 3 óbitos, todos os doentes tinham um VO2peak < 62% do valor teórico. Dois dos 3 doentes com VO2peak < 50% tiveram um âfraco resultadoâ. Com VO2peak > 75% só 3 em 20 doentes é que tiveram um âfraco resultadoâ.Apesar de reconhecerem a necessidade de mais e maiores estudos, os autores concluem que VO2peak é importante para prever complicações como óbito, enfarte do miocárdio ou insuficiência respiratória, principalmente se é referido em percentagem do valor teórico. O limite âseguroâ situar-se-ia entre 50 e 60% do valor previsto

    The anomaly of glass beads and glass beadmaking waste at Jiuxianglan, Taiwan

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    Glass beads and beadmaking waste have been excavated at the Iron Age site of Jiuxianglan (ca. third century BC–eighth century AD) in southeastern Taiwan. It was suggested that this site may be a production and exchange centre of glass beads in Iron Age Taiwan. This paper presents the analysis of 44 samples, to explore the relationship between glass beads and waste and the nature of bead production at Jiuxianglan. The analysis combines data on style, chemical composition, microstructure and distribution of glass beads and waste. The results do not show a compositional or structural match between the glass beads and glass waste, suggesting that the glass beads may not have been produced at this site

    Influence of heavy modes on perturbations in multiple field inflation

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    We investigate linear cosmological perturbations in multiple field inflationary models where some of the directions are light while others are heavy (with respect to the Hubble parameter). By integrating out the massive degrees of freedom, we determine the multi-dimensional effective theory for the light degrees of freedom and give explicitly the propagation matrix that replaces the effective sound speed of the one-dimensional case. We then examine in detail the consequences of a sudden turn along the inflationary trajectory, in particular the possible breakdown of the low energy effective theory in case the heavy modes are excited. Resorting to a new basis in field space, instead of the usual adiabatic/entropic basis, we study the evolution of the perturbations during the turn. In particular, we compute the power spectrum and compare with the result obtained from the low energy effective theory.Comment: 24 pages, 13 figures; v2 substantial changes in sec.V; v3 matching the published version on JCA
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