1,748 research outputs found

    False discovery rate: setting the probability of false claim of detection

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    When testing multiple hypothesis in a survey --e.g. many different source locations, template waveforms, and so on-- the final result consists in a set of confidence intervals, each one at a desired confidence level. But the probability that at least one of these intervals does not cover the true value increases with the number of trials. With a sufficiently large array of confidence intervals, one can be sure that at least one is missing the true value. In particular, the probability of false claim of detection becomes not negligible. In order to compensate for this, one should increase the confidence level, at the price of a reduced detection power. False discovery rate control is a relatively new statistical procedure that bounds the number of mistakes made when performing multiple hypothesis tests. We shall review this method, discussing exercise applications to the field of gravitational wave surveys.Comment: 7 pages, 3 table, 3 figures. Prepared for the Proceedings of GWDAW 9 (http://lappc-in39.in2p3.fr/GWDAW9) A new section was added with a numerical example, along with two tables and a figure related to the new section. Many smaller revisions to improve readibilit

    Metaverse in the tourism domain – introduction to the special issue

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    In times of technological innovation and digital transformation, the convergence of Metaverse and tourism emerges as a compelling and revolutionary intersection. As we stand on the edge of a new frontier in information technology, we introduce this special issue of the Journal of Information Technology and Tourism, dedicated to the multifaceted exploration of the Metaverse’s impact on the tourism industry. The Metaverse comprises interconnected digital spaces where users can engage through computer-generated environments. This convergence of cutting-edge tech- nologies, including artificial Intelligence (AI) systems, digital twins, augmented reality (AR), virtual reality (VR), blockchain, non-fungible tokens (NFTs), 3D mod- elling and simulation, cloud computing, and edge computing, defines the Metaverse’s potential. The Metaverse’s profound Influence on the tourism domain is well attested by the rigorous examinations, insightful analyses, and innovative research contributions in this issue. As we embark on this exploration, we encourage researchers, scholars, and industry experts to contribute their expertise and insights, forging a path toward a deeper understanding of the Metaverse’s implications for the future of tourism

    Controlled switching between paramagnetic and diamagnetic Meissner effect in Pb/Co nanocomposites

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    A hybrid system which consists of a superconducting (SC) Pb film (100 nm thickness) containing ∼\sim1 vol% single domain ferromagnetic (FM) Co particles of mean-size ∼\sim4.5 nm reveal unusual magnetic properties: (i) a controlled switching between the usual diamagnetic and the unusual paramagnetic Meissner effect in field cooling as well as in zero-field cooling experiments (ii) amplification of the positive magnetization when the sample enters the SC state below Tc_c. These experimental findings can be explained by the formation of spontaneous vortices and the possible alignment of these vortices due to the foregoing alignment of the Co particle FM moments by an external magnetic field.Comment: 5 pages, 3 figure

    Culturas intercalares de milho (Zea mays L.) em reflorestamentos de Pinus taeda L. no sul do Paraná.

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    Este trabalho foi planejado com o objetivo de se avaliar, na região dos Campos Gerais do Paraná, o rendimento de associações de Pinus taeda L. com milho (Zea mays L.), em função de três densidades populacionais desta cultura: 50 mil, 67 mil e 83 mil plantas/ha, dispostas, respectivamente, em duas, três e quatro linhas, entre as linhas do Pinus plantado no espaçamento de 3 x 2 m. O plantio do Pinus e o da primeira cultura de milho foram efetuados no ano agrícola 1981/82; duas novas culturas de milho foram plantadas em 1982 e em 1983. Até a terceira colheita do milho, não se registraram diferenças entre as sobrevivências do Pinus associado com duas, três e quatro linhas do cereal, nem entre estas e as da testemunha sem consórcio (média de 91,33%). Quanto à altura e ao diâmetro da espécie florestal, no entanto, os incrementos registrados no consórcio com quatro linhas de milho (3,65 m e 5,73 cm) foram menores que na testemunha sem consórcio (4,17 m e 6,92 cm), enquanto que nos consórcios com duas e três linhas, estes ficaram em posição intermediária. As produções de milho, no primeiro e no segundo ano, propiciaram, respectivamente, retornos sobre o capital investido nesta cultura, da ordem de 135 e 94%. Já no terceiro ano, quando o desenvolvimento do Pinus tornou-se suficiente para sombrear parcialmente a cultura agrícola, sua produção foi deficitária, embora em pequeno grau. A população de 50 mil plantas de milho por hectare, dispostas em duas linhas, entre as linhas do Pinus, mostrou-se a mais indicada para o sistema

    OR14-1PATTERNS AND TRANSITIONS IN SUBSTANCE USE AMONG YOUNG SWISS MEN

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    Introduction. The stages of involvement in illicit drugs other than cannabis remain vague and few studies focused on the last steps of drug-use trajectories. This study investigated this topic. Methods. We used data from the Swiss Longitudinal Cohort Study on Substance Use Risk Factors (C-SURF) to assess exposure to drug use (alcohol, tobacco, 16 illicit drugs including heroin, and five prescription drugs including opioids) at two times point (N = 5,041). Patterns and trajectories of drug use were studied using latent transition analysis (LTA) and cross-lagged panel models. Results. The LTA identified five classes of drug users showing a pattern involving adding alcohol, tobacco, cannabis, middle-stage drugs (uppers, hallucinogens, inhaled drugs), and final-stage drugs (e.g. heroin, ketamine, crystal meth). The most common transition was to remain in the same latent class. Heroin use predicted later opioid use (b = .071, p = .003) but not the reverse (b = -.005, p = .950). Conclusion. The pattern of drug use displayed the well-known sequence of drug involvement (licit drugs/cannabis/other illicit drugs), but added a distinction between "middle-stage" and "final-stage" drugs. Progression along the whole drug course remained rare among participants in their twenties. For the final stage, heroin appeared as to be a step for opioid us

    Dynamics and stability of vortex-antivortex fronts in type II superconductors

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    The dynamics of vortices in type II superconductors exhibit a variety of patterns whose origin is poorly understood. This is partly due to the nonlinearity of the vortex mobility which gives rise to singular behavior in the vortex densities. Such singular behavior complicates the application of standard linear stability analysis. In this paper, as a first step towards dealing with these dynamical phenomena, we analyze the dynamical stability of a front between vortices and antivortices. In particular we focus on the question of whether an instability of the vortex front can occur in the absence of a coupling to the temperature. Borrowing ideas developed for singular bacterial growth fronts, we perform an explicit linear stability analysis which shows that, for sufficiently large front velocities and in the absence of coupling to the temperature, such vortex fronts are stable even in the presence of in-plane anisotropy. This result differs from previous conclusions drawn on the basis of approximate calculations for stationary fronts. As our method extends to more complicated models, which could include coupling to the temperature or to other fields, it provides the basis for a more systematic stability analysis of nonlinear vortex front dynamics.Comment: 13 pages, 8 figure

    Estudo comparativo de dois métodos de arraste principal do desbaste de Pinus taeda L.

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    Desempenho e custos na operação de arraste principal de dois tratores agrícolas com implementos diferentes foram submetidos a uma análise crítica, em uma plantação de Pinus taeda, com nove anos de idade e desbastada de forma sistemática e seletiva. A pesquisa foi instalada na Fazenda Monte Alegre, município de Telêmaco Borba, PR. Foram testados tratores do tipo MF 265 e os seguintes implementos de arraste: a) barra com fendas para engatar correntes, de segurar feixes de fustes, e b) pinça hidráulica traseira e lâmina hidráulica na frente. Sob as mesmas condições de distância e volume arrastado, os rendimentos foram similares, porém apresentaram grandes diferenças, quando baseados em volumes médios da carga. O trator com barra e correntes apresentou um volume médio de 0,8 m3 por ciclo e, numa distância média de 200 m, um rendimento de 6,85 m3/h, a um custo de Cr60,80/m3.Otratorcompinc\cahidraˊulicaela^minadianteira,sobasmesmascondic\co~esdearraste,poreˊmcomumvolumemeˊdioporciclode0,5m3,atingiuumrendimentode5,39m3/h,aumcustodeCr 60,80/m3. O trator com pinça hidráulica e lâmina dianteira, sob as mesmas condições de arraste, porém com um volume médio por ciclo de 0,5 m3, atingiu um rendimento de 5,39 m3/h, a um custo de Cr 82,10/m3. Sob as condições testadas, convém utilizar o trator com barra quando houver disponibilidade de mão-de-obra, pois arrasta maior volume de madeira por unidade de tempo a um custo mais baixo e com um grau de mecanização menor, portanto menos susceptível a falhas mecânicas. A exigência de maior tempo de oficina, com consertos e manutenção, em função da necessidade do equipamento, reduz a produção média anual em 35%, aproximadamente, no caso do trator com pinça. Detectaram-se, em ambos os métodos, grandes possibilidades de racionalização e, por conseguinte, de redução dos custos de arraste entre 24 e 27%
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