501 research outputs found

    Bi-large neutrino mixing and the Cabibbo angle

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    Recent measurements of the neutrino mixing angles cast doubt on the validity of the so-far popular tri-bimaximal mixing ansatz. We propose a parametrization for the neutrino mixing matrix where the reactor angle seeds the large solar and atmospheric mixing angles, equal to each other in first approximation. We suggest such bi-large mixing pattern as a model building standard, realized when the leading order value of the reactor angle equals the Cabibbo angle.Comment: 4 pages, 2 figs. v2: matches version appearing in Phys.Rev.D, rapid communication

    SAMBA: Stochastic Analytical Model with a Bayesian Approach

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    We develop and estimate a DSGE model for the Brazilian economy, to be used as part of the macroeconomic modeling framework at the Central Bank of Brazil. The model combines the building blocks of standard DSGE models (e.g., price and wage rigidities and adjustment costs) with the following features that better describe the Brazilian economy: (i) a fiscal authority pursuing an explicit target for the primary surplus; (ii) administered or regulated prices as part of consumer prices; (iii) external finance for imports, amplifying the effects of changes in external financial conditions on the economy; and (iv) imported goods used in the production function of differentiated goods. It also includes the presence of financially constrained households. We estimate the model with Bayesian techniques, using data starting in 1999, when inflation targeting was implemented. Model evaluation, based on impulse response functions, moment conditions, variance error decomposition and initial forecasting exercises, suggests that the model can be a useful tool for policy analysis and forecasting.

    Dinâmica populacional do ácaro verde Mononychellus planki em cultivares de soja.

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    A Large Outbreak of Hepatitis E Among a Displaced Population in Darfur, Sudan, 2004: The Role of Water Treatment Methods.

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    BACKGROUND: The conflict in Darfur, Sudan, was responsible for the displacement of 1.8 million civilians. We investigated a large outbreak of hepatitis E virus (HEV) infection in Mornay camp (78,800 inhabitants) in western Darfur. METHODS: To describe the outbreak, we used clinical and demographic information from cases recorded at the camp between 26 July and 31 December 2004. We conducted a case-cohort study and a retrospective cohort study to identify risk factors for clinical and asymptomatic hepatitis E, respectively. We collected stool and serum samples from animals and performed a bacteriological analysis of water samples. Human samples were tested for immunoglobulin G and immunoglobulin M antibody to HEV (for serum samples) and for amplification of the HEV genome (for serum and stool samples). RESULTS: In 6 months, 2621 hepatitis E cases were recorded (attack rate, 3.3%), with a case-fatality rate of 1.7% (45 deaths, 19 of which involved were pregnant women). Risk factors for clinical HEV infection included age of 15-45 years (odds ratio, 2.13; 95% confidence interval, 1.02-4.46) and drinking chlorinated surface water (odds ratio, 2.49; 95% confidence interval, 1.22-5.08). Both factors were also suggestive of increased risk for asymptomatic HEV infection, although this was not found to be statistically significant. HEV RNA was positively identified in serum samples obtained from 2 donkeys. No bacteria were identified from any sample of chlorinated water tested. CONCLUSIONS: Current recommendations to ensure a safe water supply may have been insufficient to inactivate HEV and control this epidemic. This research highlights the need to evaluate current water treatment methods and to identify alternative solutions adapted to complex emergencies

    Theta-13 as a Probe of Mu-Tau symmetry for Leptons

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    Many experiments are being planned to measure the neutrino mixing parameter θ13\theta_{13} using reactor as well as accelerator neutrino beams. In this note, the theoretical significance of a high precision measurement of this parameter is discussed. It is emphasized that it will provide crucial information about different ways to understand the origin of large atmospheric neutrino mixing and move us closer towards determining the neutrino mass matrix. For instance if exact μτ\mu\leftrightarrow \tau symmetry in the neutrino mass matrix is assumed to be the reason for maximal νμντ\nu_\mu-\nu_\tau mixing, one gets θ13=0\theta_{13}=0. Whether θ13Δm2/ΔmA2\theta_{13}\simeq \sqrt{\Delta m^2_{\odot}/\Delta m^2_A} or θ13Δm2/ΔmA2\theta_{13}\simeq \Delta m^2_{\odot}/\Delta m^2_A can provide information about the way the μτ\mu\leftrightarrow \tau symmetry breaking manifests in the case of normal hierarchy. We also discuss the same question for inverted hierarchy as well as possible gauge theories with this symmetry.Comment: 12 pages; no figures; latex; more exact expressions given for some parameters and minor typos corrected; paper accepted for publication in JHE

    LHC phenomenology of supersymmetric models beyond the MSSM

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    We discuss various phenomenological aspects of supersymmetric models beyond the MSSM. A particular focus is on models which can correctly explain neutrino data and the possiblities of LHC to identify the underlying scenario.Comment: Contribution to the 16th International Symposium on Particles, Strings and Cosmology (PASCOS 2010), Valencia (Spain), July 19-23, 201

    A p-Adic Model of DNA Sequence and Genetic Code

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    Using basic properties of p-adic numbers, we consider a simple new approach to describe main aspects of DNA sequence and genetic code. Central role in our investigation plays an ultrametric p-adic information space which basic elements are nucleotides, codons and genes. We show that a 5-adic model is appropriate for DNA sequence. This 5-adic model, combined with 2-adic distance, is also suitable for genetic code and for a more advanced employment in genomics. We find that genetic code degeneracy is related to the p-adic distance between codons.Comment: 13 pages, 2 table
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