1,957 research outputs found

    Radiating Shear-Free Gravitational Collapse with Charge

    Full text link
    We present a new shear free model for the gravitational collapse of a spherically symmetric charged body. We propose a dissipative contraction with radiation emitted outwards. The Einstein field equations, using the junction conditions and an ansatz, are integrated numerically. A check of the energy conditions is also performed. We obtain that the charge delays the black hole formation and it can even halt the collapse.Comment: 22 pages, 9 figures. It has been corrected several typos and included several references. Accepted for publication in GR

    Biochemical comparison of venoms from young Colombian Crotalus durissus cumanensis and their parents

    Full text link
    Crotalus durissus cumanensis, a rattlesnake endemic to Colombia and Venezuela, is considered one of the most lethal snake species in Latin America. The aim of the present study was to compare the protein content and biological activity of the venom obtained from eight specimens of C. durissus cumanensis, namely two adults from different localities of Colombia and six offspring born in captivity. Protein profiles of crude venoms were analyzed by SDS-PAGE and RP-HPLC, and biological activities were evaluated for lethality, edema, defibrination, hemolytic and coagulant activities to assess individual venoms of adults and a pool of young snake venoms. Transient edema appeared rapidly after venom inoculation, whereas hemorrhagic effect was not observed. Differences in protein profiles, lethality, hemolytic, coagulant and defibrinating activities between both adult snake venoms were observed; those from the mother snake exhibited higher activities. Venoms from young snakes were similar to the one obtained from the mother, but the coagulant effect was stronger in offspring venoms. Notably, biological effects of the father snake venom were not comparable to those previously described for C. durissus cumanensis from Venezuela and C. durissus terrificus from Brazil, confirming the high variability of the venom from Crotalus species

    CD98hc facilitates B cell proliferation and adaptive humoral immunity.

    Get PDF
    The proliferation of antigen-specific lymphocytes and resulting clonal expansion are essential for adaptive immunity. We report here that B cell-specific deletion of the heavy chain of CD98 (CD98hc) resulted in lower antibody responses due to total suppression of B cell proliferation and subsequent plasma cell formation. Deletion of CD98hc did not impair early B cell activation but did inhibit later activation of the mitogen-activated protein kinase Erk1/2 and downregulation of the cell cycle inhibitor p27. Reconstitution of CD98hc-deficient B cells with CD98hc mutants showed that the integrin-binding domain of CD98hc was required for B cell proliferation but that the amino acid-transport function of CD98hc was dispensable for this. Thus, CD98hc supports integrin-dependent rapid proliferation of B cells. We propose that the advantage of adaptive immunity favored the appearance of CD98hc in vertebrates

    Interleukin-1 polymorphisms associated with increased risk of gastric cancer

    Get PDF
    Helicobacter pylori infection is associated with a variety of clinical outcomes including gastric cancer and duodenal ulcer disease. The reasons for this variation are not clear, but the gastric physiological response is influenced by the severity and anatomical distribution of gastritis induced by H. pylori. Thus, individuals with gastritis predominantly localized to the antrum retain normal (or even high) acid secretion, whereas individuals with extensive corpus gastritis develop hypochlorhydria and gastric atrophy, which are presumptive precursors of gastric cancer. Here we report that interleukin-1 gene cluster polymorphisms suspected of enhancing production of interleukin-1-beta are associated with an increased risk of both hypochlorhydria induced by H. pylori and gastric cancer. Two of these polymorphism are in near-complete linkage disequilibrium and one is a TATA-box polymorphism that markedly affects DNA-protein interactions in vitro. The association with disease may be explained by the biological properties of interleukin-1-beta, which is an important pro-inflammatory cytokine and a powerful inhibitor of gastric acid secretion. Host genetic factors that affect interleukin-1-beta may determine why some individuals infected with H. pylori develop gastric cancer while others do no

    Anthropometry, dietary intake, physical activity and sitting time patterns in adolescents aged 15-17 years: an international comparison in eight Latin American countries

    Get PDF
    BACKGROUND: Although there is high prevalence of obesity and other cardiovascular risk factors among Latin American adolescents, there is limited evidence on dietary intake and physical activity (PA) patterns in this population. Therefore, we characterized anthropometry, dietary intake, PA and sitting time (ST) in adolescents aged 15-17 years from eight Latin American countries. METHODS: Six hundred seventy-one adolescents (41.4% girls) from the Latin American Study of Nutrition and Health (ELANS) were included. Nutritional status was classified by four BMI (kg/m2) categories. Waist circumference (WC) was categorized as above or below thresholds. Dietary intake was assessed through two non-consecutive 24-h dietary recalls. PA and ST were measured using the International Physical Activity Questionnaire (IPAQ). We calculated overall and country-specific estimates by sex and tested for differences between boys and girls. RESULTS: Differences in the prevalence of overweightness (15.1 and 21.6%) and obesity (8.5 and 6.5%) between boys and girls, respectively, were statistically insignificant (p = 0.059). Average energy intake was 2289.7 kcal/day (95% CI: 2231-2350) for boys and 1904.2 kcal/day (95% CI: 1840-1963) for girls (p  0.05 for all outcomes). There was no statistically significant difference in the prevalence of total energy (TE) saturated fat and added sugar (>10% of TE) between girls and boys (49.6% versus 44.8 and 81.7% versus 76.1%, respectively). Prevalence of physical inactivity was 19% in boys and 43.7% in girls (p  0.05). CONCLUSIONS: These findings highlight the high prevalence of poor dietary intake and physical inactivity in adolescents from Latin American countries. Therefore, effective and sustainable strategies and programmes are needed that promote healthier diets, regular PA and reduce ST among Latin American adolescents. TRIAL REGISTRATION: Clinical Trials NCT02226627. Retrospectively registered on August 27, 2014

    A structured review of long-term care demand modelling

    Get PDF
    Long-term care (LTC) represents a significant and substantial proportion of healthcare spends across the globe. Its main aim is to assist individuals suffering with more or more chronic illnesses, disabilities or cognitive impairments, to carry out activities associated with daily living. Shifts in several economic, demographic and social factors have raised concerns surrounding the sustainability of current systems of LTC. Substantial effort has been put into modelling the LTC demand process itself so as to increase understanding of the factors driving demand for LTC and its related services. Furthermore, such modeling efforts have also been used to plan the operation and future composition of the LTC system itself. The main aim of this paper is to provide a structured review of the literature surrounding LTC demand modeling and any such industrial application, whilst highlighting any potential direction for future researchers

    JIMENA DE LA FRONTERA (Cádiz). 1:5.000

    Get PDF
    Manuscrito a plumilla en tintas negra y carmín y coloreado a la acuarela en gris, carmín, azul y siena.Indica orientación con lis en rosa de los vientos y cuadrante.Relieve representado por sombreado.Indica "Tenerias", canal, caminos y la posición de las tropas
    corecore