2,239 research outputs found

    Study of the optical behavior of skins using Monte Carlo techniques

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    Uno de los principales retos en óptica biomédica y en biofotónica es la simulación de la propagación de la luz en los tejidos biológicos. El método de Monte Carlo es la aproximación más empleada, y se puede afirmar que constituye un estándar por su flexibilidad y fiabilidad en modelar la geometría de un tejido heterogéneo. Este trabajo muestra cómo analizar el comportamiento óptico de la piel y cómo algunas de las deducciones extraídas de este análisis pueden aportar información para el diagnóstico y el tratamiento de pieles. Se han aplicado las propiedades ópticas de pieles sanas de diferentes razas y, como alteración posible en la piel, se ha estudiado la presencia del basalioma. Los resultados nos ofrecen un método para distinguir entre piel «sana» y piel «enferma», lo que podría facilitar un procedimiento de identificación de pieles cancerígenas. Del estudio de los distintos tipos de pieles sanas se desprende, además, un ejemplo de aplicación inmediata que se beneficia del conocimiento adquirido por los valores obtenidos (fotodepilación). En este trabajo se presentan los resultados más significativos de los programas de simulación basados en técnicas de Monte Carlo, que permiten estudiar el comportamiento de la piel frente a una radiación óptica. La aproximación a la trayectoria que sigue la luz en su interacción con el tejido se obtiene a partir de las propiedades ópticas conocidas a priori. Se realiza una aproximación general al tema, identificando los principales problemas que se plantean en este tipo de estudios y se emplea un programa comercial.In both biomedical optics and biophotonics, one of the main challengers is the simulation of light spread in biological tissues. The approximation which is most used is Monte Carlos method; it is a standard because of its flexibility and its reliability modeling heterogeneous tissues. This paper shows how to analyse the optical behaviour of the skin, and how some of the deductions drawn from this analysis can add information for the diagnosis and treatment of skins. The optic qualities of healthy skins from different races have been applied; and as a possible alteration in the skin, basalioma presence has been studied. The results provide us with a method to distinguish between “healthy” and “ill” skin, which could make the procedure to identify cancer skins easier. From the study of the different healthy skins an example of immediate application also appears which benefits from the knowledge acquired from the values obtained (photodepilation). In this work the most valued results of the simulation programs based in Monte Carlos technics are presented, which allow studying the skins behaviour facing an optical radiation; the approximation to the light trajectory interacting with the tissues is obtained from the optic qualities known before. First of all, a general approach to the theme is carried out, identifying the main problems that appear in this kind of studies and a commercial programme is used.Peer Reviewe

    Towards a more complete description of nucleon distortion in lepton-induced single-pion production at low-Q2Q^2

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    Theoretical predictions for lepton-induced single-pion production (SPP) on 12^{12}C are revisited in order to assess the effect of different treatments of the current operator. On one hand we have the asymptotic approximation, which consists in replacing the particle four-vectors that enter in the operator by their asymptotic values, i.e., their values out of the nucleus. On the other hand we have the full calculation, which is a more accurate approach to the problem. We also compare with results in which the final nucleon is described by a relativistic plane wave, to rate the effect of the nucleon distortion. The study is performed for several lepton kinematics, reproducing inclusive and semi-inclusive cross sections belonging to the low-Q2Q^2 region (between 0.05 and 1 GeV2^2), which is of special interest in charged-current (CC) neutrino-nucleus 1π\pi production. Inclusive electron results are compared with experimental data. We find non-trivial corrections comparable in size with the effect of the nucleon distortion, namely, corrections up to 6\%, either increasing or diminishing the asymptotic prediction, and a shift of the distributions towards higher energy transfer. For the semi-inclusive cross sections, we observe the correction to be prominent mainly at low values of the outgoing nucleon kinetic energy. Finally, for CC neutrino-induced 1π+\pi^+ production, we find a reduction at low-Q2Q^2 with respect to both the plane-wave approach and the asymptotic case

    Elastic scattering, inelastic excitation, and 1 n pick-up transfer cross sections for 10 B + 120 Sn at energies near the Coulomb barrier

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    The 10 B + 120 Sn reaction has been systematically studied at laboratory energies around the Coulomb barrier: E LAB = 31.5 , 33.5, 35.0, and 37.5 MeV. Cross sections for the elastic scattering and some reaction processes have been measured: excitation to the 1 + state of 10 B ; excitation to the 2 + and 3 − states of 120 Sn ; and the one-neutron pick-up transfer 120 Sn ( 10 B , 11 B ) 119 Sn . Coupled reaction channel (CRC) calculations have been performed in the context of the double-folding São Paulo potential. The theoretical calculations result in a good overall description of the experimental angular distributions. The effect on the theoretical elastic-scattering angular distributions of couplings to the inelastic and transfer states (through the CRC calculations) and to the continuum states (through continuum-discretized coupled-channels calculations) has been investigated.Instituto Nacional de Ciência e Tecnologia–Física Nuclear e Aplicações (INCT-FNA) 464898/2014-5Ministerio de Economía y Competitividad de España y el Fondo Europeo de Desarrollo Regional (FEDER) FIS2014-51941-P,Junta de Andalucía. FQM-160Programa de investigación e innovación de la Unión Europea Horizonte 2020. 65400

    Interaction of 8 He with 208Pb at near-barrier energies: 4 He and 6 He production

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    Spanish Ministry of Economy and Competitiveness-FPA-2010-22131-CO2-01 (FINURA) y FPA2013-47327-C2-1-RMinistry of Science and Higher Education of Poland-N202 033637National Science Centre of Poland-2013/08/M/ST2/00257 (LEA-COPIGAL) y 2014/14/M/ST2/00738 (COPIN-INFN Collaboration)European Science Foundation-EUI2009-04163432 (EUROGENESIS

    A Single Nucleotide Polymorphism in the RASGRF2 Gene Is Associated with Alcoholic Liver Cirrhosis in Men

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    Background Genetic polymorphisms in the RAS gene family are associated with different diseases, which may include alcohol-related disorders. Previous studies showed an association of the allelic variant rs26907 in RASGRF2 gene with higher alcohol intake. Additionally, the rs61764370 polymorphism in the KRAS gene is located in a binding site for the let-7 micro-RNA family, which is potentially involved in alcohol-induced inflammation. Therefore, this study was designed to explore the association between these two polymorphisms and susceptibility to alcoholism or alcoholic liver disease (ALD). Methods We enrolled 301 male alcoholic patients and 156 healthy male volunteers in this study. Polymorphisms were genotyped by using TaqMan® PCR assays for allelic discrimination. Allelic and genotypic frequencies were compared between the two groups. Logistic regression analysis was performed to analyze the inheritance model. Results The A allele of the RASGRF2 polymorphism (rs26907) was significantly more prevalent among alcoholic patients with cirrhosis (23.2%) compared to alcoholic patients without ALD (14.2%). This difference remained significant in the group of patients with alcohol dependence (28.8% vs. 14.3%) but not in those with alcohol abuse (15.1% vs. 14.4%). Multivariable logistic regression analysis showed that the A allele of this polymorphism (AA or GA genotype) was associated with alcoholic cirrhosis both in the total group of alcoholics (odds ratio [OR]: 2.33, 95% confidence interval [CI]: 1.32–4.11; P = 0.002) and in the group of patients with alcohol dependence (OR: 3.1, 95% CI: 1.50–6.20; P = 0.001). Allelic distributions of the KRAS polymorphism (rs61764370) did not differ between the groups. Conclusions To our knowledge, this genetic association study represents the first to show an association of the RASGRF2 G>A (rs26907) polymorphism with ALD in men, particularly in the subgroup of patients with AD. The findings suggest the potential relevance of the RAS gene family in alcoholism and ALD

    Application of Diamond Detectors in Tracking of Heavy Ion Slowed Down Radioactive Beams

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    Results of irradiation of thin Chemical Vapor Deposition (CVD) diamond detectors with low energy: p,α and 7Li beams are presented. Energy resolution: ΔE/E<1% of a single crystal detector was achieved. A coincident measurement with two diamond detectors showed time resolution of 100 ps and efficiency above 70%. Despite a high beam flux reaching 109 particles/s cm2 the tested detectors showed low dead-time and satisfactory radiation hardness. Perspectives of applying thin CVD diamond detectors in monitoring of a slowed down radioactive beam (RIB) are discussed.Spanish Ministry of Education and Science (MEC) FFPA2003-05958 and PA-2005-0446

    Elastic, inelastic, and 1 n transfer cross sections for the 10 B + 120 Sn reaction

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    The 10 B + 120 Sn reaction has been investigated at E Lab = 37.5 MeV. The cross sections for different channels, such as the elastic scattering, the excitation of the 2 + and 3 − 120 Sn states, the excitation of the 1 + state of 10 B , and the 1 n pick-up transfer, have been measured. One-step distorted-wave Born approximation and coupled-reaction-channels calculations have been performed in the context of the double-folding São Paulo potential. The effect of coupling the inelastic and transfer states on the angular distributions is discussed in the paper. In general, the theoretical calculations within the coupled-reaction-channels formalism yield a satisfactory agreement with the corresponding experimental angular distributions.Instituto Nacional de Ciência e Tecnologia-Física Nuclear e Aplicações de Brasil (INCT-FNA) 464898/2014-

    Planck 2013 results. XX. Cosmology from Sunyaev-Zeldovich cluster counts

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    We present constraints on cosmological parameters using number counts as a function of redshift for a sub-sample of 189 galaxy clusters from the Planck SZ (PSZ) catalogue. The PSZ is selected through the signature of the Sunyaev-Zeldovich (SZ) effect, and the sub-sample used here has a signal-to-noise threshold of seven, with each object confirmed as a cluster and all but one with a redshift estimate. We discuss the completeness of the sample and our construction of a likelihood analysis. Using a relation between mass M and SZ signal Y calibrated to X-ray measurements, we derive constraints on the power spectrum amplitude σ8 and matter density parameter Ωm in a flat ΛCDM model. We test the robustness of our estimates and find that possible biases in the Y-M relation and the halo mass function are larger than the statistical uncertainties from the cluster sample. Assuming the X-ray determined mass to be biased low relative to the true mass by between zero and 30%, motivated by comparison of the observed mass scaling relations to those from a set of numerical simulations, we find that σ8 = 0.75 ± 0.03, Ωm = 0.29 ± 0.02, and σ8(Ωm/0.27)0.3 = 0.764 ± 0.025. The value of σ8 is degenerate with the mass bias; if the latter is fixed to a value of 20% (the central value from numerical simulations) we find σ8 (Ωm/0.27)0.3 = 0.78 ± 0.01 and a tighter one-dimensional range σ8 = 0.77 ± 0.02. We find that the larger values of σ8 and Ωm preferred by Planck's measurements of the primary CMB anisotropies can be accommodated by a mass bias of about 40%. Alternatively, consistency with the primary CMB constraints can be achieved by inclusion of processes that suppress power on small scales relative to the ΛCDM model, such as a component of massive neutrinos. We place our results in the context of other determinations of cosmologicalparameters, and discuss issues that need to be resolved in order to make further progress in this field.The development of Planck has been supported by: ESA; CNES and CNRS/INSU-IN2P3-INP (France); ASI, CNR, and INAF (Italy); NASA and DoE (USA); STFC and UKSA (UK); CSIC, MICINN and JA (Spain); Tekes, AoF and CSC (Finland); DLR and MPG (Germany); CSA (Canada); DTU Space (Denmark); SER/SSO (Switzerland); RCN (Norway); SFI (Ireland); FCT/MCTES (Portugal); and PRACE (EU).Peer Reviewe

    Seismic structure of the northern continental margin of Spain from ESCIN deep seismic profiles

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    By the end of the Carboniferous, the crust of the continental shelf in northwestern Spain was made up of deeply rooted structures related to the Variscan collision. From Permian to Triassic times the tectonic setting had changed to mainly extensional and the northern Iberian continental margin underwent rifting during Late Jurassic-Early Cretaceous times, along with sea-floor spreading and the opening of the Bay of Biscay until the Late Cretaceous. Subsequently, the northern Iberian margin was active during the north-south convergence of Eurasia and Iberia in the Tertiary. A multichannel seismic experiment, consisting of two profiles, one north-south (ESCIN-4) crossing the platform margin offshore Asturias, and another (ESCIN-3) crossing the platform margin to the northwest of Galicia, was designed to study the structure of the northern Iberian margin. The ESCIN-4 stacked section reveals inverted structures in the upper crust within the Le Danois Basin. North of the steep continental slope, ESCIN-4 shows a thick sedimentary package from 6 to 9.5 s, two-way travel time (TWT). Within this latter package, a 40-km-long, north-tapering wedge of inclined, mainly south-dipping reflections is thought to represent a buried, Alpine-age accretionary prism. In the north western part of the ESCIN-3 (ESCIN-3-1) stacked section, horizontal reflections from 6.5 to 8.5 s correspond to an undisturbed package of sediments lying above oceanic-type basement. In this part of the line, a few kilometres long, strong horizontal reflection at 11.2 s within the basement may represent an oceanic Moho reflection. Also, a band of reflections dips gently towards the southeast, from the base of the gently dipping continental slope. The part of ESCIN-3 line that runs parallel to the NW-Galicia coast (ESCIN-3-2), is characterized by bright, continuous lower crustal reflections from 8 to 10 s. Beneath the lower crustal reflectivity, a band of strong reflections dips gently toward the southwest from 10 to 13.5 s. The part of ESCIN-3 that parallels the northern margin (ESCIN 3-3), shows good reflectivity in all levels. Upper crustal reflections image the sedimentary fill of probable Mesozoic to recent basins. Mid-crustal reflectivity is characterized by dipping reflections until 8 s that are probably related to compressional Variscan features. The lower crustal level shows 'layered' reflections between 8 and 12 s. Dipping reflections are found below the continental Moho.J. Alvarez-Marrón held a post-doc research grant from the Ministry of Education and Science of Spain. The ESCI-N program was sponsored by the Spanish agencies CICYT (project GEO 90-0660) and FICYT, and STRIDE Program of the EU.Peer Reviewe

    Elastic scattering of 8He + 208Pb at 22MeV

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    The dynamics of 8He around the Coulomb barrier is investigated by measuring the energy and angular distribution of the elastic 8He and the 6He and 4He fragment yields in the collision process with a 208Pb target. The experiment was carried out at SPIRAL/GANIL in October 2010. The experimental results will provide information about the relevant reaction mechanisms and the validity of the optical model (OM) when applied to exotic nuclei. In this paper, details of the experimental setup and preliminary results on the elastic scattering for the collision at 22 MeV are presented.Spanish Research Council FPA-2010-22131-CO2-01Ministry of Science and Higher Education of Poland N202 03363
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