2,375 research outputs found

    A possible origin of superconducting currents in cosmic strings

    Get PDF
    The scattering and capture of right-handed neutrinos by an Abelian cosmic string in the SO(10) grand unification model are considered. The scattering cross-section of neutrinos per unit length due to the interaction with the gauge and Higgs fields of the string is much larger in its scaling regime than in the friction one because of the larger infrared cutoff of the former.The probability of capture in a zero mode of the string accompanied by the emission of a gauge or Higgs boson shows a resonant peak for neutrino momentum of the order of its mass. Considering the decrease of number of strings per unit comoving volume in the scaling epoch the cosmological consequences of the superconducting strings formed in this regime will be much smaller than those which could be produced already in the friction one.Comment: 14 pages Latex, 4 figues/ep

    Baryogenesis through gradual collapse of vortons

    Get PDF
    We evaluate the matter-antimatter asymmetry produced by emission of fermionic carriers from vortons which are assumed to be destabilized at the electroweak phase transition.The velocity of contraction of the vorton, calculated through the decrease of its magnetic energy, originates a chemical potential which allows a baryogenesis of the order of the observed value. This asymmetry is not diluted by reheating if the collapse of vortons is distributed along an interval of ~ 10^-9 sec.Comment: 14 pages, Latex, no figure

    Infección por chlamydia trachomatis en el primer año de vida

    Get PDF
    Introducción: En la embarazada el rastreo de Chlamydia trachomatis (C. trachomatis) es controvertido. La colonización asintomática ocurre en el 2—20%. El 40—70% de los recién-nacidos son infectados. Objetivo: Caracterizar la infección por C. trachomatis en los ni˜nos con menos de 1 a˜no de edad. Material y métodos: Estudio retrospectivo de 13 a˜nos (enero de 1997 a diciembre de 2009) de las infecciones diagnosticadas en lactantes por immunofluorescencia del raspado ocular o inmunoglobulina M sérica. Se analizaron datos demográficos, clínicos, radiológicos y la evolución clínica. Resultados: Fueron incluidos 46 ni˜nos, con una incidencia de 0,7/1.000 recién nacidos vivos. La edad media fue de 2 meses (rango: 7 días-11 meses). Siete madres presentaban otras coinfecciones: virus de la inmunodeficiencia 1 (1), antígeno HBs (AgHBs) (1) y Streptococcus del grupo B (5). El parto fue vaginal en el 81,4% y en el 13,0% hubo rotura de bolsa amniótica superior a 12 h. Cinco ni˜nos fueron prematuros. Ocurrió infección respiratoria en 41 pacientes (89,1%) y conjuntivitis en 17 (36,9%). La conjuntivitis se manifestó a los primeros 30 días de vida (rango: 7—52 días) y la infección respiratoria a los 45 días de vida (rango:8 días-11 meses). Diez (29,4%) niños presentaron complicaciones: hipoxemia (9), otitis media aguda (2), apnea (3) y atelectasia (1). La radiografía de tórax mostró infiltrado intersticial en 25 casos (65,8%) y fue normal en 4 ni˜nos. La mayoría (80,5%) tuvo una evolución favorable, pero 5 ni˜nos fueron reingresados y 8 (17,4%) desarrollaron broncospasmo recurrente. Conclusiones: En el primer a˜no de vida la C. trachomatis debe considerarse entre los agentes etiológicos de conjuntivitis e infecciones respiratorias. En Portugal, la prevalencia es desconocida, pero probablemente es subdiagnosticada

    Leishmania infantum UBC1 in Metacyclic Promastigotes from Phlebotomus perniciosus, a Vaccine Candidate for Zoonotic Visceral Leishmaniasis

    Get PDF
    Leishmania parasites cause outstanding levels of morbidity and mortality in many developing countries in tropical and subtropical regions. Numerous gene expression profiling studies have been performed comparing different Leishmania species' life-cycles and stage forms in regard to their distinct infective ability. Based on expression patterns, homology to human orthologues, in silico HLA-binding predictions, and annotated functions, we were able to select several vaccine candidates which are currently under study. One of these candidates is the Leishmania infantum ubiquitin-conjugating enzyme E2 (LiUBC1), whose relative levels, subcellular location, in vitro infectivity in the U937 myeloid human cell model, and protection levels in Syrian hamsters against L. infantum infection were studied herein. LiUBC1 displays a low level of similarity with the mammalian orthologs and relevant structure differences, such as the C-terminal domain, which is absent in the human ortholog. LiUBC1 is present in highly infective promastigotes. Knock-in parasites overexpressing the enzyme increased their infectivity, according to in vitro experiments. Syrian hamsters immunized with the recombinant LiUBC1 protein did not show any parasite burden in the spleen, unlike the infection control group. The IFN-γ transcript levels in splenocytes were significantly higher in the LiUBC1 immunized group. Therefore, LiUBC1 induced partial protection against L. infantum in the Syrian hamster model.This work was financed by a contract with CZ Vaccines, Porriño, Spain, and partially defrayed by a grant from the Fundación Ramón Areces. JL thanks CZ Vaccines for the fellowship.S

    User acceptance of SaaS ERP considering perceived risk, system performance and cost

    Get PDF
    The use of cloud solution to support ERP system has become the priority of many organizations to stay competitive in the current global world. This research will be focusing on the user acceptance of SaaS ERP (SAP ByDesign) in a global construction tool provider considering perceived risk, cost and system performance. Due to many unique variables, the purpose of this research is to analyze and investigate issues related to acceptance of SaaS in the construction tool provider companies. The results of this research can help both organizations and researchers to build a fundamental level on understanding how these factors that can predict the user acceptance of SaaS ERP in a global construction tool provider company which significantly beneficial. 80 users ranging from executive and higher management level globally were targeted. SAS Enterprise Guide 5.1 was used to analyze respondents' data and SAS dataset was then run by SAS Enterprise Guide 5.1 to produce descriptive analysis, Cronbach alpha, factor analysis and PLS-SEM will be used to analyses the responses and each hypothesis will be tested based on the data consolidated. Lastly, Partial Least Square- SEM will be performed to summarize and give an analysis of the research model propose

    Reciprocal effects among changes in weight, body image, and other psychological factors during behavioral obesity treatment: a mediation analysis

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Changes in body image and subjective well-being variables (e.g. self-esteem) are often reported as outcomes of obesity treatment. However, they may, in turn, also influence behavioral adherence and success in weight loss. The present study examined associations among obesity treatment-related variables, i.e., change in weight, quality of life, body image, and subjective well-being, exploring their role as both mediators and outcomes, during a behavioral obesity treatment.</p> <p>Methods</p> <p>Participants (BMI = 31.1 ± 4.1 kg/m<sup>2</sup>; age = 38.4 ± 6.7 y) were 144 women who attended a 12-month obesity treatment program and a comparison group (n = 49), who received a general health education program. The intervention included regular group meetings promoting lasting behavior changes in physical activity and dietary intake. Body image, quality of life, subjective well-being, and body weight were measured at baseline and treatment's end. Mediation was tested by multiple regression and a resampling approach to measure indirect effects. Treatment group assignment was the independent variable while changes in weight and in psychosocial variables were analyzed alternatively as mediators and as dependent variables.</p> <p>Results</p> <p>At 12 months, the intervention group had greater weight loss (-5.6 ± 6.8% vs. -1.2 ± 4.6%, p < .001) and larger decreases in body size dissatisfaction (effect size of 1.08 vs. .41, p < .001) than the comparison group. Significant improvements were observed in both groups for all other psychosocial variables (effect sizes ranging from .31–.75, p < .05). Mediation analysis showed that changes in body image and body weight were concurrently mediators and outcomes of treatment, suggesting reciprocal influences. Weight loss partially mediated the effect of treatment on quality of life and on self-esteem but the reciprocal effect was not observed.</p> <p>Conclusion</p> <p>Changes in weight and body image may reciprocally affect each other during the course of behavioral obesity treatment. No evidence of reciprocal relationships was found for the other models under analysis; however, weight changes partially explained the effects of treatment on quality of life and self-esteem. Weight and psychosocial changes co-occur during treatment and will probably influence each other dynamically, in ways not yet adequately understood. Results from this study support the inclusion of intervention contents aimed at improving body image in weight management programs.</p

    Relationship among medical student resilience, educational environment and quality of life

    Get PDF
    Resilience is a capacity to face and overcome adversities, with personal transformation and growth. In medical education, it is critical to understand the determinants of a positive, developmental reaction in the face of stressful, emotionally demanding situations. We studied the association among resilience, quality of life (QoL) and educational environment perceptions in medical students. We evaluated data from a random sample of 1,350 medical students from 22 Brazilian medical schools. Information from participants included the Wagnild and Young's resilience scale (RS-14), the Dundee Ready Educational Environment Measure (DREEM), the World Health Organization Quality of Life questionnaire - short form (WHOQOL-BREF), the Beck Depression Inventory (BDI) and the State-Trait Anxiety Inventory (STAI). Full multiple linear regression models were adjusted for sex, age, year of medical course, presence of a BDI score >= 14 and STAI state or anxiety scores >= 50. Compared to those with very high resilience levels, individuals with very low resilience had worse QoL, measured by overall (beta=-0.89; 95% confidence interval =-1.21 to -0.56) and medical-school related (beta=-0.85; 95% CI=-1.25 to -0.45) QoL scores, environment (beta=-6.48; 95% CI=-10.01 to -2.95), psychological (beta=-22.89; 95% CI=-25.70 to -20.07), social relationships (beta=-14.28; 95% CI=-19.07 to -9.49), and physical health (beta=-10.74; 95% CI=-14.07 to -7.42) WHOQOL-BREF domain scores. They also had a worse educational environment perception, measured by global DREEM score (beta=-31.42; 95% CI=-37.86 to -24.98), learning (beta=-7.32; 95% CI=-9.23 to -5.41), teachers (beta=-5.37; 95% CI=-7.16 to -3.58), academic self-perception (beta=-7.33; 95% CI=-8.53 to -6.12), atmosphere (beta=-8.29; 95% CI=-10.13 to -6.44) and social self-perception (beta=-3.12; 95% CI=-4.11 to -2.12) DREEM domain scores. We also observed a dose-response pattern across resilience level groups for most measurements. Medical students with higher resilience levels had a better quality of life and a better perception of educational environment. Developing resilience may become an important strategy to minimize emotional distress and enhance medical training106CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPE

    Search for W' bosons decaying to an electron and a neutrino with the D0 detector

    Get PDF
    This Letter describes the search for a new heavy charged gauge boson W' decaying into an electron and a neutrino. The data were collected with the D0 detector at the Fermilab Tevatron proton-antiproton Collider at a center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity of about 1 inverse femtobarn. Lacking any significant excess in the data in comparison with known processes, an upper limit is set on the production cross section times branching fraction, and a W' boson with mass below 1.00 TeV can be excluded at the 95% C.L., assuming standard-model-like couplings to fermions. This result significantly improves upon previous limits, and is the most stringent to date.Comment: submitted to Phys. Rev. Let
    corecore