2,950 research outputs found

    Generalized soldering of ±2\pm 2 helicity states in D=2+1D=2+1

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    The direct sum of a couple of Maxwell-Chern-Simons (MCS) gauge theories of opposite helicities ±1\pm 1 does not lead to a Proca theory in D=2+1D=2+1, although both theories share the same spectrum. However, it is known that by adding an interference term between both helicities we can join the complementary pieces together and obtain the physically expected result. A generalized soldering procedure can be defined to generate the missing interference term. Here we show that the same procedure can be applied to join together ±2\pm 2 helicity states in a full off-shell manner. In particular, by using second-order (in derivatives) self-dual models of helicities ±2\pm 2 (spin two analogues of MCS models) the Fierz-Pauli theory is obtained after soldering. Remarkably, if we replace the second-order models by third-order self-dual models (linearized topologically massive gravity) of opposite helicities we end up after soldering exactly with the new massive gravity theory of Bergshoeff, Hohm and Townsend in its linearized approximation.Comment: 12 pages, to appear in Phys. Rev.

    The efficacy of hyperbaric oxygen therapy in the treatment of central retinal artery occlusion

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    Central retinal artery occlusion (CRAO) is an ophthalmological emergency. Various treatment modalities have been tried, but none have shown to alter natural history of the disease. Hyperoxia can restore retinal oxygenation, and favourable results were obtained with hyperbaric oxygen therapy (HBOT). We report two patients with sudden visual loss due to CRAO treated with HBOT. Case 1: a 61-year-old female, presented with CRAO in her left eye(OS). She was submitted to eight sessions of HBOT(2.4atmosphere absolute (ATA)). BCVA(Best corrected visual acuity) improved from counting fingers (CF) to 1.0 and fluorescein angiography (FA) showed a normalisation. Vascular study showed a value of 8.8% for HbA1c and ventricular extrasystoles. Case 2: a 69-year-old male presented with CRAO in his OS. Nine sessions of HBOT(2.4 ATA) were performed. Best corrected visual acuity (BCVA)improved from CF to 0.8 and the FA was normalised. Vascular study revealed an atheromatous carotid disease, and cardiac pathology. HBOT seems to be beneficial on the recovery of vision following CRAO.info:eu-repo/semantics/publishedVersio

    Manuel Castells and Informationalism

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    Understanding how the social appropriation of information and communication technologies came to define the contemporary period is critical for researchers and practitioners of innovation, business and management. This paper explores how the work of Manuel Castells as a social theorist provides the intellectual tools and the encompassing lenses to enable the study and navigate the process of structural transformation in which our lives have been engulfed from the 1970s onwards. Castells’ procedure of considering technology, social usages and structural history leads him to a key conceptual result: the introduction of the “Network Society” concept. His ideas have most notably been applied to the field of communications studies, which he analyses through the prism of power. However, these insights are not containable in one single discipline as the implications of informationalism stretch in a variety of directions, making other dimensions of society amenable to the network perspective. Organisational studies are one topic in which this line of enquiry may fruitfully be pursued.info:eu-repo/semantics/acceptedVersio

    Brugada syndrome complicated with sudden death

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    Brugada syndrome is an electrocardiographic diagnosis that is increasingly recognized as a cause of sudden cardiac death. The authors present a clinical case of a patient with a family history of sudden death, in whom a diagnosis of Brugada syndrome had been established, and who died suddenly. They also present a brief review of the main findings of this entity, particularly the diagnostic criteria and treatment of choice, since it is recognized that its prevalence will rise in the coming years

    A new approach to the Sachs-Wolfe effect

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    We present a new approach to the Sachs-Wolfe effect, which is based on the dynamics of photons in a space and time varying gravitational field. We consider the influence of plasma dispersion effects on photon propagation, and establish the limits of validity of the usual results of the standard cosmological approach, for the large scale temperature anisotropies of the cosmic microwave background. New dynamical contributions to the integrated Sachs-Wolfe effect are also discussed.Comment: 5 page

    Avaliação do capim-marandu sob déficit hídrico em casa de vegetação, no período de estabelecimento.

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    O objetivo deste trabalho foi avaliar o perfilhamento e a produção de biomassa do capim-marandu no período de estabelecimento, sob influência do déficit hídrico. Realizou-se o experimento em casa-de-vegetação na Embrapa Pecuária Sudeste, sob delineamento em blocos completos casualizados com arranjo fatorial 3x3+1. Os tratamentos referiram-se à suspensão da irrigação em diferentes épocas do estabelecimento (semeadura, germinação e perfilhamento primário) até que o solo apresentasse teor de água equivalente a 75, 50 e 25% da capacidade de armazenamento de água disponível no solo (CAD), além da testemunha que não sofreu restrição hídrica. As avaliações de número de perfilhos surgidos por vaso foram realizadas semanalmente, por cinco semanas, a partir do início do perfilhamento. Uma coleta de biomassa foi realizada aproximadamente 30 dias após o término do último tratamento, período em que o solo foi mantido próximo a capacidade de campo. O perfilhamento e a produção de biomassa do capim-marandu são reduzidos quando o déficit hídrico é suficiente para que o teor de água no solo atinja 25%CAD, durante a fase de estabelecimento, independente da época em que ocorra a escassez hídrica

    Detecção de ovino sororreagente para Maedi-Visna no estado de Sergipe.

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    Resumo - O vírus da Maedi-Visna pertence à família Retroviridae, gênero Lentivírus e afeta ovinos criados especialmente de forma intensiva. Apesar de variável patogenicidade, é responsável por manifestação clínica crônica e debilitante. Amplamente distribuído pelo mundo, é relacionado a subestimado impacto econômico na ovinocultura, porém com dados imprecisos no Brasil. O presente trabalho objetivou a obtenção da prevalência da Maedi-Visna no município de Lagarto/Sergipe. Foram analisadas 151 amostras séricas de ovinos Santa Inês, oriundas de nove propriedades rurais, identificadas quanto ao sexo e idade dos animais. Utilizou-se o teste de Imunodifusão em Gel de Ágar através da técnica de microaglutinação. A prevalência obtida foi de 0,66%, o que representa o primeiro relato da Maedi-Visna em Sergipe e que pode estar correlacionado ao íntimo contato entre ovinos e caprinos ou a submissão dos animais às exposições agropecuárias, inclusive extra-estaduais, onde há a aproximação de animais infectados e sadios promovida de forma inconsciente pelos produtores, ou ainda à transmissão a partir de animais exóticos inseridos em rebanho para melhoramento genético. Devido ao sistema de criação ao qual os animais são mantidos, confinamento de reprodutores e regime semi-intensivo aos demais, a doença pode não ter conseguido condições propicias para disseminar-se. O resultado indica riscos à ovinocultura desenvolvida no estado e as relações comerciais com os demais, e sugere a necessidade de estudos mais amplos para melhor caracterizar o perfil do estado em relação à ocorrência de Lentiviroses de Pequenos Ruminantes e implantação de medidas de controle e prevenção da disseminação desta enfermidade. Detection of sheep sororeaction for maedi-visna in State of Sergipe. Abstract - The virus of Maedi Visna belongs to Retroviridae family, gender Lentivirus affects raise of sheep especially at intensive way. Despite variable pathogenicity, is responsible for chronic and debilitating clinical. Widely distributed throughout the world, is linked underestimated the economic impact in raise of sheep, but with inaccurate data in Brazil. This study aimed to obtain the prevalence of Maedi Visna in the municipality of Lagarto / Sergipe. It were analyzed 151 samples of serum taken from sheep of Santa Ines breed, from nine farms, identified as to sex and age of animals. It was used in the test of Imunodifusion in Agar Gel whith microaglutination technique. The prevalence obtained was 0.66%, which represents the first report of Maedi Visna in Sergipe and can be correlated to the close contact between sheep and goats or the submission of animals for agricultural exhibitions where there is the nearest of infected and healthy animals unconscious promoted by producers or the transmission from exotic animals entered in farms for breeding herd. Because the system of creation which animals are kept, confinement of males and semi-intensive system to the others, the disease may not have achieved favorable conditions to spread itself. The results indicates the risk in raised of sheep developed in the state and trade relations with the others, and suggests the need for more extensive studies to better characterize the profile of the state in relation to the occurrence of Lentiviroses of Small Ruminants and implementation of measures for control and prevention spread of this disease

    A new approach to the Sachs-Wolfe effect

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    We present a new approach to the Sachs-Wolfe effect, which is based on the dynamics of photons in a space and time varying gravitational field. We consider the influence of plasma dispersion effects on photon propagation, and establish the limits of validity of the usual results of the standard cosmological approach, for the large scale temperature anisotropies of the cosmic microwave background. New dynamical contributions to the integrated Sachs-Wolfe effect are also discussed.Comment: 5 page
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