9,417 research outputs found

    Properties of Magnetized Quark-Hybrid Stars

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    The structure of a magnetized quark-hybrid stars (QHS) is modeled using a standard relativistic mean-field equation of state (EoS) for the description of hadronic matter. For quark matter we consider a bag model EoS which is modified perturbatively to account for the presence of a uniform magnetic field. The mass-radius (M-R) relationship, gravitational redshift and rotational Kepler periods of such stars are compared with those of standard neutron stars (NS).Comment: 5 pages, 2 figures, prepared for the 2nd International Symposium on Strong Electromagnetic Fields and Neutron Stars (SMFNS2011), Varadero, Cuba, 5-7 May 201

    Only in the people we trust": The moral structure of the Chilean urban poor's radical political discourse in the Partido Igualdad

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    Indexación: Scopus; Scielo.En el presente artículo, se analiza la estructura del discurso político radical de los pobladores chilenos, a través del caso del Partido Igualdad. La hipótesis que orienta este artículo es que el discurso que vehiculiza el Partido tiene una lógica populista centrada en el significante pueblo y elementos anti-elitistas. Si bien esta estructura coincide con la literatura contemporánea acerca del populismo, el significante pueblo estaría limitado por otros dos significantes: el “sufrimiento compartido” y la “dignidad”, lo que restringe sus posibilidades de articulación.In the present article, the structure of the radical political discourse of the Chilean squatters is analyzed through the case of the Partido Igualdad. The hypothesis that guides the article is that the discourse of the party has a populist logic centered on the signifier “the people” and anti-elitist elements. Although this structure coincides with contemporary literature about populism, the signifier “the people” would be limited by two other signifiers: "shared suffering" and "dignity", which restricts their possibilities of articulation.http://www.izquierdas.cl/images/pdf/2019/n46/art2.pd

    Measuring Security Price Performance Using Chilean Daily Stock Returns: The event Study Method

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    24 p.Siguiendo el enfoque de simulación de Brown y Warner y usando retornos diarios del mercado accionario chileno,examinamos la especificación y el poder de tres estadísticos comúnmente utilizados en estudios de evento: el test estandarizado,el de corte transversal y el de portfolio. Nuestros resultados muestran que aunque los retornos y excesos de retornos a nivel individual evidentemente no distribuyen normal, la media muestral converge hacia la normalidad en la medida que el número de acciones del portfolio muestral aumenta. Así, las pruebas estadísticas típicamente utilizadas en estudios de evento de un día estarían bien especificadas, al menos para un nivel de significancia del 5%. En términos del poder del test, el test estandarizado siempre se muestra más poderoso para capturar la presencia de un retorno anormal que sus dos competidores: el test de corte transversal y el de portfolio. También encontramos, sin embargo, que el poder de las tres pruebas estadísticas analizadas es muy sensible tanto al tamaño muestral como al número de días que involucre el evento

    Norovirus Infection and Disease in an Ecuadorian Birth Cohort: Association of Certain Norovirus Genotypes With Host FUT2 Secretor Status.

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    BACKGROUND: Although norovirus is the most common cause of gastroenteritis, there are few data on the community incidence of infection/disease or the patterns of acquired immunity or innate resistance to norovirus. METHODS: We followed a community-based birth cohort of 194 children in Ecuador with the aim to estimate (1) the incidence of norovirus gastroenteritis from birth to age 3 years, (2) the protective effect of norovirus infection against subsequent infection/disease, and (3) the association of infection and disease with FUT2 secretor status. RESULTS: Over the 3-year period, we detected a mean of 2.26 diarrheal episodes per child (range, 0-12 episodes). Norovirus was detected in 260 samples (18%) but was not found more frequently in diarrheal samples (79 of 438 [18%]), compared with diarrhea-free samples (181 of 1016 [18%]; P = .919). A total of 66% of children had at least 1 norovirus infection during the first 3 years of life, and 40% of children had 2 infections. Previous norovirus infections were not associated with the risk of subsequent infection. All genogroup II, genotype 4 (GII.4) infections were among secretor-positive children (P < .001), but higher rates of non-GII.4 infections were found in secretor-negative children (relative risk, 0.56; P = .029). CONCLUSIONS: GII.4 infections were uniquely detected in secretor-positive children, while non-GII.4 infections were more often found in secretor-negative children

    Density-Matrix functional theory of strongly-correlated lattice fermions

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    A density functional theory (DFT) of lattice fermion models is presented, which uses the single-particle density matrix gamma_{ij} as basic variable. A simple, explicit approximation to the interaction-energy functional W[gamma] of the Hubbard model is derived from exact dimer results, scaling properties of W[gamma] and known limits. Systematic tests on the one-dimensional chain show a remarkable agreement with theBethe-Ansatz exact solution for all interaction regimes and band fillings. New results are obtained for the ground-state energyand charge-excitation gap in two dimensions. A successful description of strong electron correlations within DFT is achieved.Comment: 15 pages, 6 figures Submitted to PR

    Synthesis, physicochemical and photophysical characterization of 4-(1-Pyrenyl)-Butyl-α-d-mannopyranoside

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    IndexaciĂłn: Web of Science; Scopus; Scielo.Glycolipids are biomolecules composed of a lipid chain (lipophilic) and a monosaccharide or oligosaccharide as hydrophilic group. Their chemical structure and biological role make them undoubtedly good candidates for a large and continuously growing number of biotechnological applications. Mannose is a carbohydrate present on membrane glycolipids of a wide number of pathogenic microorganisms (bacteria, fungi, protozoa, and viruses) and specifically recognized by several lectins. We synthesized a mannose derivative linked through a short methylene chain to a pyrene moiety which behaves as a surfactant, able to aggregate, and retains the photophysical properties of pyrene: showing comparable absorption and emission spectra, having lower fluorescence quantum yield and the ability to form excimer, and finally the ability to produce O-2((1)Delta(g)) with high quantum yields. Thus, this novel molecule would open future applications for detection (fluorescence) or inactivation (singlet oxygen) of bacterial pathogens, viruses, tumor cells, or particular cells.http://ref.scielo.org/pcn4d
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