319 research outputs found

    Segurança de dados aplicada a urna eletrônica com foco na autenticação

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    Este é um trabalho de natureza acadêmica que tem por objetivo oferecer outra possibilidade de segurança da informação no uso de urnas eletrônicas para votação. Baseando-se nos 3 (três) módulos distintos no procedimento de votação eletrônica, conforme fluxo descritivo do Tribunal Superior Eleitoral – TSE [1], é possível dividir em três momentos a votação eletrônica: 1. Autenticação e/ou identificação do eleitor; 2. Votação; 3. Apuração / Totalização. Este trabalho ficará restrito ao item número 1. Autenticação e/ou identificação do eleitor, sendo que o mesmo poderá vir a servir como referência a trabalhos posteriores que tenham interesse em desenvolver as demais relações do fluxo descritivo do TSE [1]. Através do estudo de viabilidade da inserção de autenticação do eleitor através de um cartão de identificação e que contenha dados codificados de validação do eleitor em sua zona eleitoral, cria-se uma nova formatação para um dos pilares da segurança da informação, a confidencialidade, o eleitor não será mais identificado no momento da votação, mas autenticado e através do cartão, o eleitor passa a ter acesso ao módulo de votação, propriamente dito, sem que seus dados tenham sido gravados ou identificados, diminuindo-se a possibilidade de quebra de sigilo ou confidencialidade da informação, disponível na eleição eletrônica e da possibilidade de cruzamento de informações para se descobrir a escolha do eleitor na eleição

    Development of Functional Microfold (M) Cells from Intestinal Stem Cells in Primary Human Enteroids.

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    Background & aimsIntestinal microfold (M) cells are specialized epithelial cells that act as gatekeepers of luminal antigens in the intestinal tract. They play a critical role in the intestinal mucosal immune response through transport of viruses, bacteria and other particles and antigens across the epithelium to immune cells within Peyer's patch regions and other mucosal sites. Recent studies in mice have demonstrated that M cells are generated from Lgr5+ intestinal stem cells (ISCs), and that infection with Salmonella enterica serovar Typhimurium increases M cell formation. However, it is not known whether and how these findings apply to primary human small intestinal epithelium propagated in an in vitro setting.MethodsHuman intestinal crypts were grown as monolayers with growth factors and treated with recombinant RANKL, and assessed for mRNA transcripts, immunofluorescence and uptake of microparticles and S. Typhimurium.ResultsFunctional M cells were generated by short-term culture of freshly isolated human intestinal crypts in a dose- and time-dependent fashion. RANKL stimulation of the monolayer cultures caused dramatic induction of the M cell-specific markers, SPIB, and Glycoprotein-2 (GP2) in a process primed by canonical WNT signaling. Confocal microscopy demonstrated a pseudopod phenotype of GP2-positive M cells that preferentially take up microparticles. Furthermore, infection of the M cell-enriched cultures with the M cell-tropic enteric pathogen, S. Typhimurium, led to preferential association of the bacteria with M cells, particularly at lower inoculum sizes. Larger inocula caused rapid induction of M cells.ConclusionsHuman intestinal crypts containing ISCs can be cultured and differentiate into an epithelial layer with functional M cells with characteristic morphological and functional properties. This study is the first to demonstrate that M cells can be induced to form from primary human intestinal epithelium, and that S. Typhimurium preferentially infect these cells in an in vitro setting. We anticipate that this model can be used to generate large numbers of M cells for further functional studies of these key cells of intestinal immune induction and their impact on controlling enteric pathogens and the intestinal microbiome

    Determination of density and concentration from fluorescent images of a gas flow

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    A fluorescent image analysis procedure to determine the distribution of species concentration and density in a gas flow is proposed. The fluorescent emission is due to the excitation of atoms/molecules of a gas that is intercepted by an electron blade. The intensity of the fluorescent light is proportional to the local number density of the gas. When the gas flow is a mixture of different species, this proportionality can be exploited to extract the contribution associated to the species from the spectral superposition acquired by a digital camera. This yields a method that simultaneously reveals species concentrations and mass density of the mixture. The procedure is applied to two under-expanded sonic jets discharged into a different gas ambient - Helium into Argon and Argon into Helium - to measure the concentration and density distribution along the jet axis and across it. A comparison with experimental and numerical results obtained by other authors when observing under-expanded jets at different Mach numbers is made with the density distribution along the axis of the jet. This density distribution appears to be self-similar.Comment: New figures in portable .eps forma

    Portable monitoring devices in the diagnosis of obstructive sleep apnea: current status, advantages, and limitations

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    Recent years have seen a growing interest in the use of portable monitoring devices for the diagnosis of obstructive sleep apnea syndrome. These have the potential to be used in lieu of the more complicated and uncomfortable alternative, polysomnography, which has long been considered to be the gold standard for the diagnosis of this relatively prevalent condition. Following their approval in 2008 by the Center of Medicare and Medicaid Services, the federal agency which administers Medicare and Medicaid in the United States, there has been extensive discussion about the utility and validity of these devices for use in the diagnosis of obstructive sleep apnea syndrome. Although there are various models of portable monitoring devices, the literature contains little information regarding how each device should be used in specific age groups, patients presenting comorbidities, and asymptomatic patients. Additionally, studies about the cost-effectiveness of this diagnostic method are scarce and conflicting. Therefore, this objective of this study was to review what has been learned about portable monitoring devices over time, as well as to examine the recent progress, advantages, limitations, and applications of these devices in the diagnosis of obstructive sleep apnea syndrome in different groups of patients.Nos últimos anos, é crescente o interesse pela utilização de aparelhos de monitoramento portáteis para o diagnóstico da síndrome da apneia obstrutiva do sono, como uma alternativa mais simples e confortável à polissonografia, que é o exame considerado o padrão ouro para o diagnóstico dessa condição relativamente prevalente. A liberação do uso desses equipamentos pelo Center of Medicare and Medicaid Services, agência federal que administra os serviços médicos nos Estados Unidos da América, em 2008, resultou em ampla discussão sobre a utilidade e validade desses equipamentos para o diagnóstico de síndrome da apneia obstrutiva do sono. Apesar de haver vários modelos de equipamentos de monitorização portátil, há pouca informação na literatura a respeito de como cada equipamento deveria ser utilizado em grupos etários específicos, portadores de comorbidades e pacientes assintomáticos. Além disso, estudos de custo-efetividade desse método diagnóstico são escassos e conflitantes. Portanto, o objetivo do presente estudo foi revisar a evolução dos conhecimentos no uso de equipamentos de monitorização portátil, bem como examinar os avanços recentes, vantagens, limitações e aplicações desses equipamentos para o diagnóstico de apneia obstrutiva do sono em diferentes grupos de pacientes.Universidade Federal de São Paulo (UNIFESP) Departamento de PsicobiologiaUniversidade Federal de São Paulo (UNIFESP)Escola de Medicina Santa Casa de MisericórdiaUNIFESP, Depto. de PsicobiologiaUNIFESPSciEL

    Explaining LSND by a decaying sterile neutrino

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    We propose an explanation of the LSND evidence for electron antineutrino appearance based on neutrino decay. We introduce a heavy neutrino, which is produced in pion and muon decays because of a small mixing with muon neutrinos, and then decays into a scalar particle and a light neutrino, predominantly of the electron type. We require values of gm4g m_4\sim few eV, gg being the neutrino--scalar coupling and m4m_4 the heavy neutrino mass, e.g. m4m_4 in the range from 1 keV to 1 MeV and g106103g \sim 10^{-6} - 10^{-3}. Performing a fit to the LSND data as well as all relevant null-result experiments, we show that all data can be explained within this decay scenario. In the minimal version of the decay model, we predict a signal in the upcoming MiniBooNE experiment corresponding to a transition probability of the same order as seen in LSND. In addition, we show that extending our model to two nearly degenerate heavy neutrinos it is possible to introduce CP violation in the decay, which can lead to a suppression of the signal in MiniBooNE running in the neutrino mode. We briefly discuss signals in future neutrino oscillation experiments, we show that our scenario is compatible with bounds from laboratory experiments, and we comment on implications in astrophysics and cosmology.Comment: 23 pages, 5 figures, minor improvements, matches published versio

    The Swift X-ray flaring afterglow of GRB 050607

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    The unique capability of the Swift satellite to perform a prompt and autonomous slew to a newly detected Gamma-Ray Burst (GRB) has yielded the discovery of interesting new properties of GRB X-ray afterglows, such as the steep early lightcurve decay and the frequent presence of flares detected up to a few hours after the GRB trigger. We present observations of GRB 050607, the fourth case of a GRB discovered by Swift with flares superimposed on the overall fading X-ray afterglow. The flares of GRB 050607 were not symmetric as in previously reported cases, showing a very steep rise and a shallower decay, similar to the Fast Rise, Exponential Decay that are frequently observed in the gamma-ray prompt emission. The brighter flare had a flux increase by a factor of approximately 25,peaking for 30 seconds at a count rate of approximately 30 counts s-1, and it presented hints of addition short time scale activity during the decay phase. There is evidence of spectral evolution during the flares. In particular, at the onset of the flares the observed emission was harder, with a gradual softening as each flare decayed. The very short time scale and the spectral variability during the flaring activity are indicators of possible extended periods of energy emission by the GRB central engine. The flares were followed by a phase of shallow decay, during which the forward shock was being refreshed by a long-lived central engine or by shells of lower Lorentz factors, and by a steepening after approximately 12 ks to a decay slope considered typical of X-ray afterglows.Comment: 23 pages, 5 figures, Accepted by the Astrophysical Journa

    A New Supersymmetric Index

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    We show that Tr(1)FFeβH{\rm Tr}(-1)^F F e^{-\beta H} is an index for NN=2 supersymmetric theories in two dimensions, in the sense that it is independent of almost all deformations of the theory. This index is related to the geometry of the vacua (Berry's curvature) and satisfies an exact differential equation as a function of β\beta. For integrable theories we can also compute the index thermodynamically, using the exact SS-matrix. The equivalence of these two results implies a highly non-trivial equivalence of a set of coupled integral equations with these differential equations, among them Painleve III and the affine Toda equations.Comment: 60 page

    Assessment of Gastric Phenotypes Using Magnifying Narrow-Band Imaging for Differentiation of Gastric Carcinomas from Adenomas

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    Background. Conventional white-light endoscopy and forceps biopsy are insufficient for definitive diagnosis of gastric adenoma. Immunohistochemical studies have reported an obvious phenotypic difference between adenomas and carcinomas. We investigated the utility of narrow-band imaging with magnifying endoscopy (NBI-ME) for mucin phenotypic assessment to differentiate carcinomas from adenomas. Methods. NBI-ME findings were classified into A, B, and AB types, which revealed papillary, tubular pits and groove microstructures, respectively. To investigate A-B classifications retrospectively, 137 patients (155 lesions) that were diagnosed pretherapeutically with adenoma or borderline lesions by biopsy were enrolled. The mucin phenotype was analyzed immunohistochemically in the first 60 lesions. Results. After endoscopic submucosal dissection, A type and AB type lesions were determined histologically as carcinoma (81/82, 99%). B type lesions were adenoma (29/73, 40%) and carcinoma (44/73, 60%). A or AB type correlated to histological carcinomas (sensitivity 65%, specificity 97%, and accuracy 71%). Mucin phenotypes were gastric or gastrointestinal in A type and AB type carcinomas (31/37, 84%) and intestinal in B type adenomas and carcinomas (21/23, 91%). Conclusions. NBI-ME has the advantage of the assessment of mucin phenotypes in gastric carcinomas and adenomas. The proposed A-B classification is useful, especially for differentiation of gastric or gastrointestinal carcinomas from adenomas

    Subphthalocyanine encapsulated within MIL-101(Cr)-NH2 as a solar light photoredox catalyst for dehalogenation of alpha-haloacetophenones

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    [EN] Subphthalocyanine has been incorporated into a robust metal-organic framework having amino groups as binding sites. The resulting SubPc@MIL-101(Cr)-NH2 composite has a loading of 2 wt%. Adsorption of subphthalocyanine does not deteriorate host crystallinity, but decreases the surface area and porosity of MIL-101(Cr)-NH2. The resulting SubPc@MIL-101(Cr)-NH2 composite exhibits a 575 nm absorption band responsible for the observed photoredox catalytic activity under simulated sunlight irradiation for hydrogenative dehalogenation of alpha-haloacetophenones and for the coupling of alpha-bromoacetophenone and styrene. The material undergoes a slight deactivation upon reuse. In comparison to the case of phthalocyanines the present study is one of the few cases showing the use of subphthalocyanine as a photoredox catalyst, with its activity derived from site isolation within the MOF cavities.Financial support from the Spanish Ministry of Economy and Competitiveness (Severo Ochoa and RTI2018-098237-B-C21) and Generalitat Valenciana (Prometeo 2017-083) is gratefully acknowledged. S. N. is thankful for the financial support from the Fundacion Ramon Areces (XVIII Concurso Nacional para la Adjudicacion de Ayudas a la Investigacion en Ciencias de la Vida y de la Materia, 2016), the Ministerio de Ciencia, Innovacion y Universidades RTI 2018-099482-A-I00 project and the Generalitat Valenciana grupos de investigacion consolidables 2019 (ref: AICO/2019/214) project. S. 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    Mutant p53 drives clonal hematopoiesis through modulating epigenetic pathway

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    Clonal hematopoiesis of indeterminate potential (CHIP) increases with age and is associated with increased risks of hematological malignancies. While TP53 mutations have been identified in CHIP, the molecular mechanisms by which mutant p53 promotes hematopoietic stem and progenitor cell (HSPC) expansion are largely unknown. Here we discover that mutant p53 confers a competitive advantage to HSPCs following transplantation and promotes HSPC expansion after radiation-induced stress. Mechanistically, mutant p53 interacts with EZH2 and enhances its association with the chromatin, thereby increasing the levels of H3K27me3 in genes regulating HSPC self-renewal and differentiation. Furthermore, genetic and pharmacological inhibition of EZH2 decreases the repopulating potential of p53 mutant HSPCs. Thus, we uncover an epigenetic mechanism by which mutant p53 drives clonal hematopoiesis. Our work will likely establish epigenetic regulator EZH2 as a novel therapeutic target for preventing CHIP progression and treating hematological malignancies with TP53 mutations
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