268 research outputs found

    Pines’ demon observed as a 3D acoustic plasmon in Sr₂RuO₄

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    Sr2RuO4での「パインズの悪魔」の観測 67年前に予言された金属の奇妙な振る舞いの発見. 京都大学プレスリリース. 2023-08-10.Speak of the Demon: Discovery of strange behavior of new plasmons predicted in the 50s. 京都大学プレスリリース. 2023-09-25.The characteristic excitation of a metal is its plasmon, which is a quantized collective oscillation of its electron density. In 1956, David Pines predicted that a distinct type of plasmon, dubbed a ‘demon’, could exist in three-dimensional (3D) metals containing more than one species of charge carrier. Consisting of out-of-phase movement of electrons in different bands, demons are acoustic, electrically neutral and do not couple to light, so have never been detected in an equilibrium, 3D metal. Nevertheless, demons are believed to be critical for diverse phenomena including phase transitions in mixed-valence semimetals, optical properties of metal nanoparticles, soundarons in Weyl semimetals and high-temperature superconductivity in, for example, metal hydrides. Here, we present evidence for a demon in Sr₂RuO₄ from momentum-resolved electron energy-loss spectroscopy. Formed of electrons in the β and γ bands, the demon is gapless with critical momentum qc = 0.08 reciprocal lattice units and room-temperature velocity v = (1.065 ± 0.12) × 10⁵ m s⁻¹ that undergoes a 31% renormalization upon cooling to 30 K because of coupling to the particle–hole continuum. The momentum dependence of the intensity of the demon confirms its neutral character. Our study confirms a 67-year old prediction and indicates that demons may be a pervasive feature of multiband metals

    Neotropical freshwater fisheries : A dataset of occurrence and abundance of freshwater fishes in the Neotropics

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    The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications

    Reversal of diabetic-induced myopathy by swimming exercise in pregnant rats:a translational intervention study

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    Gestational diabetes mellitus (GDM) plus rectus abdominis muscle (RAM) myopathy predicts long-term urinary incontinence (UI). Atrophic and stiff RAM are characteristics of diabetes-induced myopathy (DiM) in pregnant rats. This study aimed to determine whether swimming exercise (SE) has a therapeutic effect in mild hyperglycemic pregnant rats model. We hypothesized that SE training might help to reverse RAM DiM. Mild hyperglycemic pregnant rats model was obtained by a unique subcutaneous injection of 100 mg/kg streptozotocin (diabetic group) or citrate buffer (non-diabetic group) on the first day of life in Wistar female newborns. At 90 days of life, the rats are mated and randomly allocated to remain sedentary or subjected to a SE protocol. The SE protocol started at gestational day 0 and consisted of 60 min/day for 6 days/week in a period of 20 days in a swim tunnel. On day 21, rats were sacrificed, and RAM was collected and studied by picrosirius red, immunohistochemistry, and transmission electron microscopy. The SE protocol increased the fiber area and diameter, and the slow-twitch and fast-twitch fiber area and diameter in the diabetic exercised group, a finding was also seen in control sedentary animals. There was a decreased type I collagen but not type III collagen area and showed a similar type I/type III ratio compared with the control sedentary group. In conclusion, SE during pregnancy reversed the RAM DiM in pregnant rats. These findings may be a potential protocol to consider in patients with RAM damage caused by GDM

    Planejamento e qualidade da gestão no âmbito do Serviço Único de Saúde - SUS: desafios no município de São Luís – MA

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    Introdução: A implementação do SUS representou um aumento das atividades e serviços de saúde existentes e oferecidos à população. E a gestão do sistema de saúde torna-se de fundamental importância, acima de tudo, seus processos de planejamento. Neste sentido, a trajetória do Decreto 7.508/2011 que regulamenta a Lei de Saúde Orgânica (Lei nº 8.080/1990) revela um caminho marcado pelo esforço de melhorar o planejamento dentro do sistema. Com isso, algumas ferramentas formais de intervenção administrativa para qualificar a gestão do SUS tornaram-se evidentes. Considerando a relevância do tema abordado e o contexto do problema de pesquisa, a questão é: como a administração municipal de São Luís - MA dentro do SUS pode qualificar seu processo de planejamento? Objetivo: Discutir o conhecimento dos gestores sobre planejamento na gestão municipal. Material e Método: Este é um estudo exploratório, cuja abordagem do problema é qualitativa. A amostra é não-probabilística, intencional por conveniência, e o instrumento de coleta de dados foi a entrevista semi-estruturada. Este entendimento do cenário foi possível a partir das declarações das pessoas entrevistadas, mas também a partir da observação dos participantes do autor. Os gerentes foram entrevistados em abril de 2021, e a técnica de Análise de Conteúdo foi utilizada na modalidade proposta por Gomes e Minayo (2015) Resultados: As categorias de análise: Percepção sobre Gestão; Qualificação de Pessoas e Conhecimento das Normas do SUS. A pesquisa mostrou um contexto de gestão municipal que ainda carece de planejamento que fortalece e qualifica os processos de trabalho

    Economic profitability of yellow passion fruit in organic cultivationunder different input levels and irrigation

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    The productivity of passion fruit is low compared to its productive potential which in organic system is due to rainfed cultivation and low input levels. The aim of this work was to evaluate the profitability of yellow passion fruit production in organic system under different input levels and irrigation. The experiment was carried out in Rio Branco - AC, at the Seridó Ecological Site, conducted from November 2016 to August 2018. Randomized block design was used, arranged in a factorial scheme (3x2) with four replicates. The factors evaluated were: three input levels of inputs (fertilizers and alternative pesticides) and presence or absence of irrigation. Fertilization was carried out based on the nutrient content of the soil analysis and according to the yield estimate 5 t ha-1, 10 t ha-1 and 15 t ha-1. The irrigation used was with a micro sprinkler per plant. The production cost, profitability, simplified economic analysis, production for total and operating coverage were calculated based on capital depreciation, input level and labor during two cultivation years. The highest input level and irrigation increase productivity, total revenue and production requirements to cover total and operating costs. Fixed cost is higher when using combination of irrigation and input level 1; however, it provided positive economic yields.A produtividade de maracujá é baixa comparado ao seu potencial produtivo que em sistema orgânico é decorrência do cultivo de sequeiro e baixo uso de insumos. O objetivo desse trabalho foi avaliar a rentabilidade da produção de maracujá amarelo em sistema orgânico sob diferentes níveis de insumos e irrigação. O experimento foi realizado em Rio Branco – AC, no Sítio Ecológico Seridó, conduzidos no período de novembro de 2016 a agosto de 2018. Foi utilizado o delineamento em blocos casualizados, disposto em esquema fatorial (3x2) com quatro repetições. Os fatores avaliados foram: três níveis de insumos (fertilizantes e defensivos alternativos), com presença e ausência de irrigação. A adubação foi realizada com base nos teores de nutrientes da análise de solo e de acordo com a estimativa de produtividade 5 t ha-1, 10 t ha-1 e 15 t ha-1. A irrigação utilizada foi com um microaspersor por planta. O custo de produção, a rentabilidade, a análise econômica simplificada, a produção para cobertura total e operacional foram calculadas com base na depreciação do capital, uso de insumos e mão de obra durante dois anos de cultivo. O maior aporte de insumos e a irrigação elevam a produtividade, a receita total e a necessidade de produção para cobrir os custos operacionais e totais. O custo fixo é maior quando se faz o uso conjunto de irrigação e nível 1 de insumo, mesmo assim, proporcionam rendimentos econômicos positiv

    A ética do silêncio racial no contexto urbano: políticas públicas e desigualdade social no Recife, 1900-1940

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    Mais de meio século após o preconceito racial ter se tornado o principal alvo dos movimentos urbanos pelos direitos civis nos Estados Unidos e na África do Sul, e décadas depois do surgimento dos movimentos negros contemporâneos no Brasil, o conjunto de ferramentas legislativas criado no Brasil para promover o direito à cidade ainda adere à longa tradição brasileira de silêncio acerca da questão racial. Este artigo propõe iniciar uma exploração das raízes históricas desse fenômeno, remontando ao surgimento do silêncio sobre a questão racial na política urbana do Recife, Brasil, durante a primeira metade do século XX. O Recife foi eé um exemplo paradigmático do processo pelo qual uma cidade amplamente marcada por traços negros e africanos chegou a ser definida política e legalmente como um espaço pobre, subdesenvolvido e racialmente neutro, onde as desigualdades sociais originaram na exclusão capitalista, e não na escravidão e nas ideologias do racismo científico. Neste sentido, Recife lança luzes sobre a política urbana que se gerou sob a sombra do silêncio racial.More than half a century after racial prejudice became central to urban civil rights movements in the United States and South Africa, and decades after the emergence of Brazil’s contemporary Black movements, Brazil's internationally recognized body of rights-to-the-city legislation still adheres to the country's long historical tradition of racial silence. This article explores the historical roots of this phenomenon by focusing on the emergence of racial silence in Recife, Brazil during the first half of the 20th Century. Recife was and remains a paradigmatic example of the process through which a city marked by its Black and African roots came to be legally and politically defined as a poor, underdeveloped and racially neutral space, where social inequalities derived from capitalist exclusion rather than from slavery and scientific racism. As such, Recife'sexperience sheds light on the urban policies that were generated in the shadow of racial silence

    Incoherent Change Detection Methods for Wavelength-Resolution SAR Image Stacks Based on Masking Techniques

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    This paper presents two incoherent change detection methods for wavelength-resolution synthetic aperture radars (SAR) image stacks based on masking techniques. The first technique proposed is the Simple Masking Detection (SMD). This method uses the statistical behavior of pixels-sets in the image stack to create a binary mask, which is used to remove pixels that are not related to changes in a surveillance image from the same interest region. The second technique is the Multiple Concatenated Masking Detection (MCMD), which produces a more selective mask than the SMD by concatenating multiple masks from different image stacks. The MCMD can be used in specific applications where multiple stacks share common patterns of target deployments. Both proposed techniques were evaluated using 24 incoherent SAR images obtained by the CARABAS II system. The experimental results revealed that the proposed detection methods have better performance in terms of probability of detection and false alarm rate when compared with other change detection techniques, especially for high detection probabilities scenarios.open access</p
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