3,449 research outputs found

    Deciphering age and origin of gullied-shaped landscapes in Sierra de las Nieves National Park (South of Spain)

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    This study aims to shed light on the age and origin of these gullied and badland morphologies located in the upper area from the Sierra de las Nieves National Park. Origin of gullies and badlands usually is related to either climate or human activity shifts, more common in cold regions the former whilst in semiarid regions the latter. In this case, Sierra de las Nieves, mainly of built on calcareous rocks, is characterised by Mediterranean mountain climate and a long tradition of human activity in previous centuries. The experimental area is located in its upper part forming plateu-like relief where calcareous hills are separated by valleys of lower slopes filled with marls and quaternary sediments. Gullies and badlands are located in these materials. Vegetation corresponds to an opened-mixed vegetal formation of Quercus Faginea and Abies pinsapo Boiss. with typical high mountain shrubs and meadows. To carry out the study, one transect was defined in one selected gullied-area including 15-sampling points and ecogeomorphology described: vegetation, soil surface conditions, and geomorphic processes. In addition, soils were also sampled in depth at the same points and some properties analysed in laboratory. The transect run along the maximum slope line from one hill to the valley bottom and continue towards the top of the opposite hill. In the valley bottom, there was a fluvial Quaternary deposit covering and fossilising the marls formation. When outcropped, these marls were affected by concentrate water erosion forming gullies. Also, its surface developed typical morphologies of Badlands: cracks and crusts in dry conditions, short and shallow mudflows in wet conditions, and popcorn in winter. In that deposit, samples were taking in depth until the marls was reached and dated by means C14 technique. Ecogeomorphology inventory, soil properties, and datations have been used to shed light on the age and origin of the formation of gullies and badlands.Trabajo financiado por: -Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Proyecto del Plan Propio B3_2020-5. -Proyecto UMA20-FEDERJA-097-EGeoland

    Delimitación de unidades ecogeográficas originales y comparación con la zonificación del Parque Natural y Geoparque Sierras Subbéticas (Córdoba) (CÓRDOBA)

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    En el Parque Natural y Geoparque Sierras Subbéticas (provincia de Córdoba), los criterios utilizados para delimitar la zonificación de espacios naturales protegidos no atienden a una base metodológica concreta, ni están alineados con la normativa que rige los Planes de Ordenación de Recursos Naturales. Ante esto, es necesario establecer una metodología científica con unos criterios específicos que actualice conceptos y consiga que: objetivos, normativa y políticas de sostenibilidad ambiental, vayan de la mano en la gestión de estos espacios. La Ecogeografia y su visión sistémica del territorio, integrando el medio físico-natural y la transformación histórica realizada por el ser humano, da lugar a la creación de diferentes tipos de paisajes que pueden ser de gran ayuda para los gestores y técnicos a la hora de la delimitación, evaluación y revisión de las zonas de protección de un ENP. Un primer paso se da en este trabajo donde, a partir de la delimitación y descripción de las unidades ecogeográficas originales, nos aproximamos al estado de conservación del paisaje dentro de un marco evolutivo espacio-temporal, en este caso, aplicado al Parque Natural y Geoparque Sierras Subbéticas, en la provincia de Córdoba.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Conservation and variability of hepatitis B core at different chronic hepatitis stages

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    Since it is currently not possible to eradicate hepatitis B virus (HBV) infection with existing treatments, research continues to uncover new therapeutic strategies. HBV core protein, encoded by the HBV core gene (HBC), intervenes in both structural and functional processes, and is a key protein in the HBV life cycle. For this reason, both the protein and the gene could be valuable targets for new therapeutic and diagnostic strategies. Moreover, alterations in the protein sequence could serve as potential markers of disease progression. To detect, by next-generation sequencing, HBC hyper-conserved regions that could potentially be prognostic factors and targets for new therapies. Thirty-eight of 45 patients with chronic HBV initially selected were included and grouped according to liver disease stage [chronic hepatitis B infection without liver damage (CHB, n = 16), liver cirrhosis (LC, n = 5), and hepatocellular carcinoma (HCC, n = 17)]. HBV DNA was extracted from patients' plasma. A region between nucleotide (nt) 1863 and 2483, which includes HBC, was amplified and analyzed by next-generation sequencing (Illumina MiSeq platform). Sequences were genotyped by distance-based discriminant analysis. General and intergroup nt and amino acid (aa) conservation was determined by sliding window analysis. The presence of nt insertion and deletions and/or aa substitutions in the different groups was determined by aligning the sequences with genotype-specific consensus sequences. Three nt (nt 1900-1929, 2249-2284, 2364-2398) and 2 aa (aa 117-120, 159-167) hyper-conserved regions were shared by all the clinical groups. All groups showed a similar pattern of conservation, except for five nt regions (nt 1946-1992, 2060-2095, 2145-2175, 2230-2250, 2270-2293) and one aa region (aa 140-160), where CHB and LC, respectively, were less conserved (P < 0.05). Some group-specific conserved regions were also observed at both nt (2306-2334 in CHB and 1935-1976 and 2402-2435 in LC) and aa (between aa 98-103 in CHB and 28-30 and 51-54 in LC) levels. No differences in insertion and deletions frequencies were observed. An aa substitution (P79Q) was observed in the HCC group with a median (interquartile range) frequency of 15.82 (0-78.88) vs 0 (0-0) in the other groups (P < 0.05 vs CHB group). The differentially conserved HBC and HBV core protein regions and the P79Q substitution could be involved in disease progression. The hyper-conserved regions detected could be targets for future therapeutic and diagnostic strategies

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

    Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

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    Results of a search for H → τ τ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb−1 and 20.3 fb−1 at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV respectively. All combinations of leptonic (τ → `νν¯ with ` = e, µ) and hadronic (τ → hadrons ν) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of µ = 1.43 +0.43 −0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

    Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

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    Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

    Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

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    The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured
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