692 research outputs found

    Tertiary clastic gipsum deposits in the Madrid basin (Spain)

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    Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

    An event in the iberoamerican cooperation for the conservation and utilization of the zoogenetic resources

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    Between 1st and 4th of December, 2003; an event was celebrated in the city of Recife (Pernambuco, Brazil) congregating more than 200 researchers of 16 countries, to present results and discuss the last advances in the Iberoamerican Zoogenetics Resources Conservation and Utilization Area, taking into account contents over Genetics, Assisted reproduction, Rural development and Ethnology. In the present editorial a slight introduction is developed to locate the reader in the objectives, the contents and the development of the event, standing out the rule developed by the organizers, the supporters and the contributors.Del uno al cuatro de diciembre de 2003 se celebró en la ciudad de Recife (Pernambuco, Brasil) un evento que congregó a más de 200 investigadores de 16 países, para presentar resultados y discutir los últimos avances en el área de la conservación y utilización de los Recursos Zoogenéticos de Iberoamérica, tratándose contenidos sobre Genética, Reproducción asistida, Desarrollo rural, y Etnología principalmente. En la presente editorial se realiza una somera introducción para ubicar al lector en los objetivos, los contenidos y el desarrollo del evento, resaltando el papel desarrollado por los organizadores, patrocinadores y participantes

    Charged Higgs bosons in the Next-to MSSM (NMSSM)

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    The charged Higgs boson decays H±W±A1H^\pm\to W^\pm A_1 and H±W±hiH^\pm\to W^\pm h_i are studied in the framework of the next-to Minimal Supersymmetric Standard Model (NMSSM). It is found that the decay rate for H±W±A1H^\pm\to W^\pm A_1 can exceed the rates for the τ±ν\tau^\pm\nu and tbtb channels both below and above the top-bottom threshold. The dominance of H±W±A1H^\pm\to W^\pm A_1 is most readily achieved when A1A_1 has a large doublet component and small mass. We also study the production process ppH±A1pp\to H^\pm A_1 at the LHC followed by the decay H±W±A1H^\pm\to W^\pm A_1 which leads to the signature W±A1A1W^\pm A_1 A_1. We suggest that ppH±A1p p\to H^\pm A_1 is a promising discovery channel for a light charged Higgs boson in the NMSSM with small or moderate tanβ\tan\beta and dominant decay mode H±W±A1H^\pm \to W^\pm A_1. This W±A1A1W^\pm A_1 A_1 signature can also arise from the Higgsstrahlung process ppW±h1pp\to W^\pm h_1 followed by the decay h1A1A1h_1\to A_1 A_1. It is shown that there exist regions of parameter space where these processes can have comparable cross sections and we suggest that their respective signals can be distinguished at the LHC by using appropriate reconstruction methods.Comment: 20 pages, 22 eps figures, more reference adde

    Effect of calcium carbonate addition to helix aspersa müller diet

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    In this paper is studied the effect of calcium carbonate addition to diet on growth, mortality rate and feed intake of snails Helix aspersa Müller during the juvenile stage under laboratory conditions. Two treatments have been tested; first one with 12.5 percent and second one with 22.5 percent of calcium carbonate. Five groups of 40 snails have been randomly assigned to each treatment. Results show significant (p<0.05) differences between both treatments; in the second one is obtained a higher growth and lower mortality rate; however there is no significant difference for dry matter intake.En el presente trabajo se estudia el efecto de la adición de carbonato de calcio a la dieta sobre el crecimiento, mortalidad y consumo del caracol Helix aspersa Müller durante la fase de alevinaje y en condiciones de laboratorio. Se plantean dos tratamientos; el I con 12,5 p.100 y el II con 22,5 p.100 de carbonato cálcico. A cada tratamiento se le asignan aleatoriamente cinco lotes de 40 animales. Los resultados muestran diferencias significativas (p<0,05) entre ambos tratamientos; obteniéndose con el tratamiento II mayor crecimiento y menor mortalidad; que no se aprecian diferencias significativas respecto al consumo de materia seca

    Precision Electroweak Data and Unification of Couplings in Warped Extra Dimensions

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    Warped extra dimensions allow a novel way of solving the hierarchy problem, with all fundamental mass parameters of the theory naturally of the order of the Planck scale. The observable value of the Higgs vacuum expectation value is red-shifted, due to the localization of the Higgs field in the extra dimension. It has been recently observed that, when the gauge fields propagate in the bulk, unification of the gauge couplings may be achieved. Moreover, the propagation of fermions in the bulk allows for a simple solution to potentially dangerous proton decay problems. However, bulk gauge fields and fermions pose a phenomenological challenge, since they tend to induce large corrections to the precision electroweak observables. In this article, we study in detail the effect of gauge and fermion fields propagating in the bulk in the presence of gauge brane kinetic terms compatible with gauge coupling unification, and we present ways of obtaining a consistent description of experimental data, while allowing values of the first Kaluza Klein mode masses of the order of a few TeV.Comment: 32 pages, 7 figures. References adde

    The Electroweak Phase Transition on Orbifolds with Gauge-Higgs Unification

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    The dynamics of five dimensional Wilson line phases at finite temperature is studied in the one-loop approximation. We show that at temperatures of order T \sim 1/L, where L is the length of the compact space, the gauge symmetry is always restored and the electroweak phase transition appears to be of first order. Particular attention is devoted to the study of a recently proposed five dimensional orbifold model (on S1/Z2) where the Wilson line phase is identified with the Higgs field (gauge-Higgs unification). Interestingly enough, an estimate of the leading higher-loop ``daisy'' (or ``ring'') diagram contributions to the effective potential in a simple five dimensional model, seems to suggest that the electroweak phase transition can be studied in perturbation theory even for Higgs masses above the current experimental limit of 114 GeV. The transition is still of first order for such values of the Higgs mass. If large localized gauge kinetic terms are present, the transition might be strong enough to give baryogenesis at the electroweak transition.Comment: 35 pages, 34 figures; v2: discussion on higher loop contributions improved, two figures added, minor correction

    Are the magnetic fields of millisecond pulsars ~ 10^8 G?

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    It is generally assumed that the magnetic fields of millisecond pulsars (MSPs) are 108\sim 10^{8}G. We argue that this may not be true and the fields may be appreciably greater. We present six evidences for this: (1) The 108\sim 10^{8} G field estimate is based on magnetic dipole emission losses which is shown to be questionable; (2) The MSPs in low mass X-ray binaries (LMXBs) are claimed to have <1011< 10^{11} G on the basis of a Rayleygh-Taylor instability accretion argument. We show that the accretion argument is questionable and the upper limit 101110^{11} G may be much higher; (3) Low magnetic field neutron stars have difficulty being produced in LMXBs; (4) MSPs may still be accreting indicating a much higher magnetic field; (5) The data that predict 108\sim 10^{8} G for MSPs also predict ages on the order of, and greater than, ten billion years, which is much greater than normal pulsars. If the predicted ages are wrong, most likely the predicted 108\sim 10^{8} G fields of MSPs are wrong; (6) When magnetic fields are measured directly with cyclotron lines in X-ray binaries, fields 108\gg 10^{8} G are indicated. Other scenarios should be investigated. One such scenario is the following. Over 85% of MSPs are confirmed members of a binary. It is possible that all MSPs are in large separation binaries having magnetic fields >108> 10^{8} G with their magnetic dipole emission being balanced by low level accretion from their companions.Comment: 16 pages, accept for publication in Astrophysics and Space Scienc

    Role of a cryptic tRNA gene operon in survival under translational stress

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    As compared to eukaryotes, bacteria have a reduced tRNA gene set encoding between 30 and 220 tRNAs. Although in most bacterial phyla tRNA genes are dispersed in the genome, many species from distinct phyla also show genes forming arrays. Here, we show that two types of arrays with distinct evolutionary origins exist. This work focuses on long tRNA gene arrays (L-arrays) that encompass up to 43 genes, which disseminate by horizontal gene transfer and contribute supernumerary tRNA genes to the host. Although in the few cases previously studied these arrays were reported to be poorly transcribed, here we show that the L-array of the model cyanobacterium Anabaena sp. PCC 7120, encoding 23 functional tRNAs, is largely induced upon impairment of the translation machinery. The cellular response to this challenge involves a global reprogramming of the transcriptome in two phases. tRNAs encoded in the array are induced in the second phase of the response, directly contributing to cell survival. Results presented here show that in some bacteria the tRNA gene set may be partitioned between a housekeeping subset, which constantly sustains translation, and an inducible subset that is generally silent but can provide functionality under particular conditions.Ministerio de Ciencia, Innovación y Universidades [BFU2016-77097-P to I.L., A.H.; BIO2017-84066-R to F.J.R-C.]; Agencia Estatal de Investigación [PID2019-104784RJ-100/AEI/10.13039/501100011033 to R.L.I.]; National Science Foundation [MCB-1715840 to M.I.]. RB-M's lab at University of Alicante is a member of Proteored, PRB3 and is supported by grant PT17/0019, of the PE I+D+i 2013-2016, funded by ISCIII and ERDF. Funding for open access charge: Consejo Superior de Investigaciones Científicas

    Efficacy of direct current generated by multiple-electrode arrays on F3II mammary carcinoma: experiment and mathematical modeling

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    BACKGROUND: The modified Gompertz equation has been proposed to fit experimental data for direct current treated tumors when multiple-straight needle electrodes are individually inserted into the base perpendicular to the tumor long axis. The aim of this work is to evaluate the efficacy of direct current generated by multiple-electrode arrays on F3II mammary carcinoma that grow in the male and female BALB/c/Cenp mice, when multiple-straight needle electrodes and multiple-pairs of electrodes are inserted in the tumor. METHODS: A longitudinal and retrospective preclinical study was carried out. Male and female BALB/c/Cenp mice, the modified Gompertz equation, intensities (2, 6 and 10 mA) and exposure times (10 and 20 min) of direct current, and three geometries of multiple-electrodes (one formed by collinear electrodes and two by pair-electrodes) were used. Tumor volume and mice weight were measured. In addition, the mean tumor doubling time, tumor regression percentage, tumor growth delay, direct current overall effectiveness and mice survival were calculated. RESULTS: The greatest growth retardation, mean doubling time, regression percentage and growth delay of the primary F3II mammary carcinoma in male and female mice were observed when the geometry of multiple-pairs of electrodes was arranged in the tumor at 45, 135, 225 and 325o and the longest exposure time. In addition, highest direct current overall effectiveness (above 66%) was observed for this EChT scheme. CONCLUSIONS: It is concluded that electrochemical therapy may be potentially addressed to highly aggressive and metastic primary F3II murine mammary carcinoma and the modified Gompertz equation may be used to fit data of this direct current treated carcinoma. Additionally, electrochemical therapy effectiveness depends on the exposure time, geometry of multiple-electrodes and ratio between the direct current intensity applied and the polarization current induced in the tumor
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