1,146 research outputs found

    On the existence of an upper critical dimension for systems within the KPZ universality class

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    In this work we extend the etching model to d+1d+1 dimensions. This permits us to investigate its exponents behaviour on higher dimensions, to try to verify the existence of an upper critical dimension for the KPZ equations, with our results sugesting that d=4d=4 is not an upper critical dimension for the etching model

    A Year at the Forefront of Proteostasis and Aging

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    During aging, animals experience a decline in proteostasis activity, including loss of stress-response activation, culminating in the accumulation of misfolded proteins and toxic aggregates, which are causal in the onset of some chronic diseases. Finding genetic and pharmaceutical treatments that can increase organismal proteostasis and lengthen life is an ongoing goal of current research. The regulation of stress responses by cell non-autonomous mechanisms appears to be a potent way to impact organismal healthspan. In this Review, we cover recent findings in the intersection of proteostasis and aging, with a special focus on articles and preprints published between November 2021 and October 2022. A significant number of papers published during this time increased our understanding of how cells communicate with each other during proteotoxic stress. Finally, we also draw attention to emerging datasets that can be explored to generate new hypotheses that explain age-related proteostasis collapse

    Aphandra natalia(Arecaceae) – un recurso poco conocido de piassaba en el oeste de la Amazonía

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    Aphandra natalia(Balslev & Henderson) Barfod is a multipurpose palm that is exploited both commercially and for subsistence purposes. Its fibers are important in Peruvian and Ecuadorean broom industries and support many people economically. In Brazil, it is found in the western part of Acre, where it is the main source for a local broom market. Data from fieldwork in Peru (2007) suggests that the variation in gross profit per kilogram of fiber is considerable among the different segments in the broom industry. Harvesters and distributors earn negligible amounts of money whereas manufacturers reap of the major part of the earnings. Fiber extraction appears to be sustainable in Ecuador and in some parts of Peru, whereas in other parts of Peru unsustainable harvest occurs, involving felling of entire palm trees for the harvest of fibers. The same destructive extraction method is used in Brazil, where the palm is becoming rare in its natural distribution area.La palmera de piasaba (piassava, piassaba) —Aphandra natalia(Balslev& Henderson) Barfod es una palma que se utiliza para muchos propósitos, tanto comerciales como para la subsistencia de pueblos rurales. Sus fibras son de importancia económica en industrias de escobas en Perú y Ecuador, las cuales sostienen económicamente a muchas personas. En Brasil, esta palma se encuentra en la parte oeste del estado de Acre, donde sus fibras constituyen el recurso principal para el mercado local de escobas. Información de campo originada en Perú en el año 2007, muestra que existe una importante variación en las ganancias económicas por kilo de fibra entre los diferentes sectores de la industria de escobas. Los que cosechan y distribuyen los productos obtienen ganancias muy reducidas, mientras que los productores de escobas son los que más ganan. La extracción de fibras parece ser sostenible en Ecuador y en algunas partes de Perú, mientras que en otras partes de Perú se tumban palmeras enteras para sacar la fibra, lo cual representa un método no sostenible. La misma forma destructiva de cosecha de las fibras existe en Brasil, lo cual ha traído como consecuencia que las poblaciones de la palma se encuentran muy disminuidas en su hábitat natural

    Departamento de Dermatologia: histórico, seus professores e suas contribuições científicas

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    Study of the X-ray properties of the neutron-star binary 4U 1728-34 from the soft to hard state

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    We studied five XMM-Newton observations of the neutron-star binary 4U 1728-34 covering the hard, intermediate and soft spectral states. By jointly fitting the spectra with several reflection models, we obtained an inclination angle of 25-53deg\deg and an iron abundance up to 10 times the solar. From the fits with reflection models, we found that the fluxes of the reflection and the Comptonised components vary inconsistently; since the latter is assumed to be the illuminating source, this result possibly indicates the contribution of the neutron star surface/boundary layer to the disc reflection. As the source evolved from the relatively soft to the intermediate state, the disc inner radius decreased, opposite to the prediction of the standard accretion disc model. We also explore the possible reasons why the supersolar iron abundance is required by the data and found that this high value is probably caused by the absence of the hard photons in the XMM-Newton data.Comment: 14 pages, 6 figure

    O turnaround da Bunge nos anos 90

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    A longevidade empresarial é um assunto central em estratégia empresarial. As empresas de maior longevidade são as que superaram a tendência para a inércia e para se concentrarem na replicação do que sempre fizeram e conseguem operar mudanças estratégicas profundas. Estas mudanças podem incluir a reconfiguração da sua carteira de competências e negócios e a passagem de testemunho para uma gestão profissional. Fazer as mudanças internas e recuperar descreve um processo de turnaround. Neste artigo ilustramos o processo de turnaround da Bunge Limited, na década de 90. Ultrapassadas as dificuldades a empresa assumiu a liderança mundial em diversos segmentos do agronegócio. O objetivo é compreender como as empresas se podem reestruturar e recuperar de crises, com um foco particular sobre como a empresa reconfigura a sua carteira de negócios e de recursos, identifica os elementos estratégicos e a forma como faz a alocação dos recursos. A fundamentação teórica se concentrou no processo de turnaround empresarial e nos recursos utilizados durante o processo, segundo a abordagem da RBV.Estratégia, RBV, Turnaround, Longevidade

    Aspirin modulates LPS-induced nitric oxide release in rat glial cells

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    Nitric oxide and prostaglandins are among the numerous substances released by activated glial cells. The aim of this study was to evaluate the effect of high-level aspirin on iNOS expression in cultured rat glial cells treated with lipopolysaccharide (LPS) as pathological stimulator. Using Western Blotting, we verified that aspirin enhanced LPS-induced iNOS expression and the presence of 15-deoxy-Delta(12,14)-prostaglandin (15d-PGJ(2)) suppressed this aspirin effect. However, the exposure of LPS-treated glial cells to aspirin resulted in a decrease of NO production. These results suggest that aspirin interferes with the cross-talk of prostaglandins and NO, blocking the endogenous negative control exerted by COX products on iNOS expression. On the other side, aspirin seems to act directly on iNOS reducing its activity, even if it does not completely block NO release by LPS-stimulated glial cells. Then aspirin could maintain homeostatic functions of NO, while it prevents toxic effects, corresponding to high NO concentrations. (c) 2005 Elsevier Ireland Ltd. All rights reserved

    The Role of Intramolecular Epitope Spreading in the Pathogenesis of Endemic Pemphigus Foliaceus (Fogo Selvagem)

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    We report here a relationship between intramolecular epitope spreading and the clinical onset of the endemic form of pemphigus foliaceus in a Brazilian community with a high prevalence and incidence of the disease. Also known as Fogo Selvagem (FS), this disease is characterized by severe skin blistering and pathogenic anti–desmoglein-1 (Dsg1) autoantibodies. These autoantibodies bind the Dsg1 ectodomain and trigger keratinocyte cell detachment, the hallmark of FS. We show that (a) sera from FS patients in the preclinical stage recognized epitopes on the COOH-terminal EC5 domain of Dsg1, (b) disease onset was associated with the emergence of antibodies specific for epitopes on the NH2-terminal EC1 and EC2 domains, (c) all sera from FS patients with active disease recognized the EC1 and/or EC2 domains, and (d) sera from FS patients in remission showed reactivity restricted to EC5. These results suggest that anti-Dsg1 autoantibodies in FS are initially raised against the COOH-terminal EC5 domain of Dsg1 in individuals without skin disease; in genetically predisposed subjects the autoimmune response may then undergo intramolecular epitope spreading toward epitopes on the NH2-terminal EC1 and EC2 domains of Dsg1 leading to disease onset. Moreover, intramolecular epitope spreading may also modulate remissions and relapses of FS
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