3,531 research outputs found

    Radiative decay Z_H-> \gamma A_H in the little Higgs model with T-parity

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    In the little Higgs model with T-parity (LHTM), the only tree-level kinematically allowed two-body decay of the Z_H boson is Z_H-> A_H H and thus one-loop induced two-body decays may have a significant rate. We study the Z_H-> \gamma A_H decay, which is induced at the one-loop level by a fermion triangle and is interesting as it depends on the mechanism of anomaly cancellation of the model. All the relevant two- and three-body decays of the Z_H gauge boson arising at the tree-level are also calculated. We consider a small region of the parameter space where the scale of the symmetry breaking f is still allowed to be as low as 500 GeV by electroweak precision data. We first analyze the scenario of a Higgs boson with a mass of 120 GeV. We found that the Z_H->\gamma A_H branching ratio can be of the order of a tree-level three-body decay and may be at the reach of detection at the LHC for f close to 500 GeV, but it may be difficult to detect for f=1 TeV. There is also an scenario where the Higgs boson has an intermediate mass such that the Z_H-> A_H H decay is closed, the Z_H-> \gamma A_H gets considerably enhanced and the chances of detection get a large boost.Comment: 19 pages, 9 figures, 2 table

    Tobacco Taxes as the Unsung Hero: Impact of a Tax Increase on Advancing Sustainable Development in Colombia

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    Objective: Tobacco taxes are a well-established cost-effective policy to prevent Noncommunicable Diseases. This paper evaluates the expected effects of a tobacco tax increase on the Sustainable Development Goals in Colombia. Methods: We use microsimulation to build an artificial society that mimics the observed characteristics of Colombia’s population, and from there we simulate the behavioral response to a tax increase of COP$4,750 (an increase that has been discussed by policy makers and legislators) and the subsequent effects in all SDGs. Results: The tobacco tax hike reduces the number of smokers (from 4.51 to 3.45 MM smokers) and smoking intensity, resulting in a drop in the number of cigarettes smoked in Colombia (from 332.3 to 215.5 MM of 20-stick packs). Such reduction is expected to decrease premature mortality, healthcare costs, poverty and people facing catastrophic expenditure on healthcare, to increase health, income and gender equity, and to strengthen domestic resource mobilization even in the presence of illicit cigarettes. Conclusion: Tobacco taxes are an effective intervention for public health and a powerful instrument to advance on the 2030 Sustainable Development Agenda. Relevance: A comprehensive analysis of the impact of tobacco taxes on all areas of Sustainable Development is missing in the empirical literature. Such perspective is needed to break the barriers for further tobacco tax increases by gathering wider societal support, especially from stakeholders and key decision makers from development areas other than health. SDG Nr: SDG3 (health), SDG 1 (no poverty), SDG 4 (education), SDG 5 (gender equality), SDG6 (water), SDG10 (inequality), SDG12 (responsible production and consumption), SDG17 (partnerships)

    Influencia de la concentración de la salmuera en la difusión de azúcares y cloruro de sodio durante el procesamiento de aceitunas verdes variedad Arauco

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    The green olive variety Arauco were debittered using lye concentrations of, 2.50% NaOH.They were then subjected to two rinsing processes with tap water. Next, the olives were cured with brines at 7%, 10% and 13% sodium chloride concentration. During this curing process, the loss of reducing sugars from the olives, and the diffusion of sodium chloride into the olives were quantified. Effective diffusion coefficients of both solutes in the skin and the flesh were calculated for this period using a diffusion model for a composite hollow sphere. The skin effective diffusion coefficients for both solutes ranged from entre 8,27x10-14- m2/s to 4,04x10-13 m2/s. The flesh coefficients varied from 2,92x10-9 m2/s to 3,99x10-9 m2/s for sodium chloride and from 9,76x10-11 m2/s to 2,22x10-10 m2/s for reducing sugars.Aceitunas verdes variedad Arauco fueron tratadas con soluciones de hidróxido de sodio al 2,5%. Estas fueron luego sometidas a dos procesos de lavado con agua corriente. Posteriormente, las aceitunas fueron curadas en salmueras con concentraciones de 7%, 10% y 13% de cloruro de sodio. Durante este proceso de curado, se cuantificó la pérdida de azúcares reductores desde, y la difusión de cloruro de sodio hacia el interior de las aceitunas. Durante este período se calcularon los coeficientes efectivos de difusión de ambos solutos en la piel y la pulpa, utilizando un modelo de difusión en una esfera hueca compuesta. Los coeficientes efectivos de difusión de ambos solutos en la piel estuvieron en un rango entre 8,27x10-14- m2/s y 4,04x10-13 m2/s. Los coeficientes de la pulpa variaron entre 2,92x10-9 m2/s y 3,99x10-9 m2/s para el cloruro de sodio, y entre 9,76x10-11 m2/s y 2,22x10-10 m2/s para los azúcares reductores

    Magnetic structure and phase diagram of the Heisenberg-Ising spin chain antiferromagnetic PbCo2_{2}V2_{2}O8_{8}

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    The effective spin-1/2 antiferromagnetic Heisenberg-Ising chain materials, ACo2_2V2_2O8_8, A = Sr, Ba, are a rich source of exotic fundamental phenomena and have been investigated for their model magnetic properties both in zero and non-zero magnetic fields. Here we investigate a new member of the family, namely PbCo2_2V2_2O8_8. We synthesize powder and single crystal samples of PbCo2_2V2_2O8_8 and determine its magnetic structure using neutron diffraction. Furthermore, the magnetic field/temperature phase diagrams for magnetic field applied along the c, a, and [110] crystallographic directions in the tetragonal unit cell are determined via magnetization and heat capacity measurements. A complex series of phases and quantum phase transitions are discovered that depend strongly on both the magnitude and direction of the field. Our results show that \pcvo is an effective spin-1/2 antiferromagnetic Heisenberg-Ising chain with properties that are in general comparable to those of SrCo2_2V2_2O8_8 and BaCo2_2V2_2O8_8. One interesting departure from the results of these related compounds, is however, the discovery of a new field-induced phase for the field direction H∥H\|[110] which has not been previously observed

    Salmonella Pathogenesis and Processing of Secreted Effectors by Caspase-3

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    The enteric pathogen Salmonella enterica serovar Typhimurium causes food poisoning resulting in gastroenteritis. The S. Typhimurium effector Salmonella invasion protein A (SipA) promotes gastroenteritis by functional motifs that trigger either mechanisms of inflammation or bacterial entry. During infection of intestinal epithelial cells, SipA was found to be responsible for the early activation of caspase-3, an enzyme that is required for SipA cleavage at a specific recognition motif that divided the protein into its two functional domains and activated SipA in a manner necessary for pathogenicity. Other caspase-3 cleavage sites identified in S. Typhimurium appeared to be restricted to secreted effector proteins, which indicates that this may be a general strategy used by this pathogen for processing of its secreted effectors

    Subthreshold dynamics of the neural membrane potential driven by stochastic synaptic input

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    In the cerebral cortex, neurons are subject to a continuous bombardment of synaptic inputs originating from the network's background activity. This leads to ongoing, mostly subthreshold membrane dynamics that depends on the statistics of the background activity and of the synapses made on a neuron. Subthreshold membrane polarization is, in turn, a potent modulator of neural responses. The present paper analyzes the subthreshold dynamics of the neural membrane potential driven by synaptic inputs of stationary statistics. Synaptic inputs are considered in linear interaction. The analysis identifies regimes of input statistics which give rise to stationary, fluctuating, oscillatory, and unstable dynamics. In particular, I show that (i) mere noise inputs can drive the membrane potential into sustained, quasiperiodic oscillations (noise-driven oscillations), in the absence of a stimulus-derived, intraneural, or network pacemaker; (ii) adding hyperpolarizing to depolarizing synaptic input can increase neural activity (hyperpolarization-induced activity), in the absence of hyperpolarization-activated currents

    Association of Patients’ Epidemiological Characteristics and Comorbidities with Severity and Related Mortality Risk of SARS-CoV-2 Infection: Results of an Umbrella Systematic Review and Meta-Analysis

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    The objective of this study was to assess the association between patients’ epidemiological characteristics and comorbidities with SARS-CoV-2 infection severity and related mortality risk. An umbrella systematic review, including a meta-analysis examining the association between patients’ underlying conditions and severity (defined as need for hospitalization) and mortality of COVID-19, was performed. Studies were included if they reported pooled risk estimates of at least three underlying determinants for hospitalization, critical disease (ICU admission, mechanical ventilation), and hospital mortality in patients diagnosed with SARS-CoV-2 infection. Evidence was summarized as pooled odds ratios (pOR) for disease outcomes with 95% confidence intervals (95% CI). Sixteen systematic reviews investigating the possible associations of comorbidities with severity or death from COVID-19 disease were included. Hospitalization was associated with age > 60 years (pOR 3.50; 95% CI 2.97–4.36), smoking habit (pOR 3.50; 95% CI 2.97–4.36), and chronic pulmonary disease (pOR 2.94; 95% CI 2.14–4.04). Chronic pulmonary disease (pOR 2.82; 95% CI 1.92–4.14), cerebrovascular disease (pOR 2.74; 95% CI 1.59–4.74), and cardiovascular disease (pOR 2.44; 95% CI 1.97–3.01) were likely to be associated with increased risk of critical COVID-19. The highest risk of mortality was associated with cardiovascular disease (pOR 3.59; 95% CI 2.83–4.56), cerebrovascular disease (pOR 3.11; 95% CI 2.35–4.11), and chronic renal disease (pOR 3.02; 95% CI 2.61–3.49). In conclusion, this umbrella systematic review provides a comprehensive summary of meta-analyses examining the impact of patients’ characteristics on COVID-19 outcomes. Elderly patients and those cardiovascular, cerebrovascular, and chronic renal disease should be prioritized for pre-exposure and post-exposure prophylaxis and early treatment
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