292 research outputs found

    Gradient Pattern Analysis of Cosmic Structure Formation: Norm and Phase Statistics

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    This paper presents the preliminary results of the characterization of pattern evolution in the process of cosmic structure formation. We are applying on N-body cosmological simulations data the technique proposed by Rosa, Sharma & Valdivia (1999) and Ramos et al. (2000) to estimate the time behavior of asymmetries in the gradient field. The gradient pattern analysis is a well tested tool, used to build asymmetrical fragmentation parameters estimated over a gradient field of an image matrix able to quantify a complexity measure of nonlinear extended systems. In this investigation we work with the high resolution cosmological data simulated by the Virgo consortium, in different time steps, in order to obtain a diagnostic of the spatio-temporal disorder in the matter density field. We perform the calculations of the gradient vectors statistics, such as mean, variance, skewness, kurtosis, and correlations on the gradient field. Our main goal is to determine different dynamical regimes through the analysis of complex patterns arising from the evolutionary process of structure formation. The results show that the gradient pattern technique, specially the statistical analysis of second and third gradient moment, may represent a very useful tool to describe the matter clustering in the Universe.Comment: Accepted for publication in Physica

    Coping with suboptimal water temperature: modifications in blood parameters, body composition, and postingestive-driven diet selection in Nile tilapia fed two vegetable oil blends

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    The world tilapia production faces seasonal variations. However, very few nutritional studies have addressed suboptimal temperature. We evaluated the effect of two temperatures (20 or 30 °C) and two vegetable oil blends (one rich in corn oil (COR) and one rich linseed oil (LIN)) on tilapia growth, body composition, and blood parameters using a 2 × 2 factorial design with the following treatments: COR-20; LIN-20; COR-30; LIN-30 (Trial 1). In addition, we also evaluated the effect of postingestive signals of dietary oils when the organoleptic properties of diets were isolated (Trial 2). In the Trial 1, 256 fish (15.36 ± 0.14 g) were placed in 16 aquariums and submitted during 30 days to the 2 × 2 factorial designs: COR-20; LIN-20; COR-30; LIN-30. The temperatures were established in two independent water recirculation systems. In the Trial 2, 96 fish (34.02 ± 0.79 g) were placed in 12 aquariums and subjected to the same experimental design of Trial 1, but to evaluate fish feeding behavior. They were allowed to select the encapsulated diets provided in different feeding halls to evaluate if diet preferences are influenced by postingestive signals. As the Trial 1 results show, diets had no significant effects on growth, dietary protein use, and body centesimal composition, but 30 °C induced the best performance and protein deposition (P < 0.05). LIN-20 showed lower very-low-density lipoprotein and cortisol, but higher high-density lipoprotein (HDL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and triglycerides (TG) than COR-20 (P < 0.05). COR-30 presented higher HDL, AST, ALT, TG, and cortisol than LIN-30. The fish fed COR showed lower C20:5n-3 (EPA) and higher n-6 than fish fed LIN (P < 0.05). The fish fed LIN had high n-3 highly unsaturated fatty acid. ∑ polyunsaturated fatty acid was higher at 30 °C. Finally, the tilapia in Trial 2 showed clear diet intake regulation and preference for LIN (P < 0.05), regardless of temperature. In short, lipid sources had no influence on tilapia performance; however, temperature affects carcass lipid deposition as well as fatty acids profile. Notably, the preference for linseed oil can suggest nutritional metabolic issues, contributing to animal behavior knowledge

    Nonextensivity and Galaxy Clustering in the Universe

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    We investigate two important questions about the use of the nonextensive thermostatistics (NETS) formalism in the context of nonlinear galaxy clustering in the Universe. Firstly, we define a quantitative criterion for justifying nonextensivity at different physical scales. Then, we discuss the physics behind the ansatz of the entropic parameter q(r)q(r). Our results suggest the approximate range where nonextensivity can be justified and, hence, give some support to the applicability of NETS to the study of large scale structures.Comment: 8 pages, written version of a talk presented in the International Workshop on Trends and Perspectives on Extensive and Non-Extensive Statistical Mechanics. Accepted for publication in Physica

    Tentativas De Suicídio E Suicídios Na Atenção Pré-hospitalar

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    To characterize suicide attempts and suicides in a city in Northwestern Parana State, attended in the pre-hospital care. Methods: Descriptive, cross-sectional study, performed with pre-hospital care records to 257 victims of suicide and suicide attempt, in the period in 2005 to 2012, through two-dimensional analysis by chi-square. Results: There were 180 attempted suicides and 76 suicides. The age ranged 13-93 years, mean 33.5 ± 15.1 years and most prevalent in young male population. The events concentrated on the months of spring and summer, in the urban area. The use of biting object was the most used method, followed by poisoning and precipitation high places. Conclusion: To know the characteristics, methods and aggravating factors provide subsidies for the implementation of prevention measures. © 2016, Editora Cientifica Nacional Ltda. All rights reserved.65323123

    Mesoscopic models for DNA stretching under force: new results and comparison to experiments

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    Single molecule experiments on B-DNA stretching have revealed one or two structural transitions, when increasing the external force. They are characterized by a sudden increase of DNA contour length and a decrease of the bending rigidity. It has been proposed that the first transition, at forces of 60--80 pN, is a transition from B to S-DNA, viewed as a stretched duplex DNA, while the second one, at stronger forces, is a strand peeling resulting in single stranded DNAs (ssDNA), similar to thermal denaturation. But due to experimental conditions these two transitions can overlap, for instance for poly(dA-dT). We derive analytical formula using a coupled discrete worm like chain-Ising model. Our model takes into account bending rigidity, discreteness of the chain, linear and non-linear (for ssDNA) bond stretching. In the limit of zero force, this model simplifies into a coupled model already developed by us for studying thermal DNA melting, establishing a connexion with previous fitting parameter values for denaturation profiles. We find that: (i) ssDNA is fitted, using an analytical formula, over a nanoNewton range with only three free parameters, the contour length, the bending modulus and the monomer size; (ii) a surprisingly good fit on this force range is possible only by choosing a monomer size of 0.2 nm, almost 4 times smaller than the ssDNA nucleobase length; (iii) mesoscopic models are not able to fit B to ssDNA (or S to ss) transitions; (iv) an analytical formula for fitting B to S transitions is derived in the strong force approximation and for long DNAs, which is in excellent agreement with exact transfer matrix calculations; (v) this formula fits perfectly well poly(dG-dC) and λ\lambda-DNA force-extension curves with consistent parameter values; (vi) a coherent picture, where S to ssDNA transitions are much more sensitive to base-pair sequence than the B to S one, emerges.Comment: 14 pages, 9 figure

    Quantum Oscillations In Eufe2 As2 Single Crystals

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    Quantum oscillation measurements provide relevant information about the Fermi surface (FS) properties of strongly correlated metals. Here, we report on the Shubnikov-de Haas effect via high-field resistivity measurements of EuFe2As2 (Eu122) and BaFe2As2 (Ba122) single crystals. Although both pnictide compounds are isovalent with similar effective masses and density of states, at the Fermi level, our results reveal subtle changes in their fermiology. Remarkably, although the spin-density-wave (SDW) ordering temperature is higher in the Eu-rich end, Eu122 displays a much more isotropic and three-dimensional-like FS when compared with Ba122, in agreement with band structure calculations. Our experimental results suggest an anisotropic contribution of the Fe 3d orbitals to the FS in Ba122. We speculate that this orbital differentiation may be responsible for the suppression of the SDW phase in the FeAs-based compounds.9019Kamihara, Y., Watanabe, T., Hirano, M., Hosono, H., (2008) J. 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    Possible Unconventional Superconductivity In Substituted Bafe 2 As 2 Revealed By Magnetic Pair-breaking Studies

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    The possible existence of a sign-changing gap symmetry in BaFe 2 As 2 -derived superconductors (SC) has been an exciting topic of research in the last few years. To further investigate this subject we combine Electron Spin Resonance (ESR) and pressure-dependent transport measurements to investigate magnetic pair-breaking effects on BaFe 1.9 M 0.1 As 2 (M = Mn, Co, Cu, and Ni) single crystals. An ESR signal, indicative of the presence of localized magnetic moments, is observed only for M = Cu and Mn compounds, which display very low SC transition temperature (T c) and no SC, respectively. From the ESR analysis assuming the absence of bottleneck effects, the microscopic parameters are extracted to show that this reduction of T c cannot be accounted by the Abrikosov-Gorkov pair-breaking expression for a sign-preserving gap function. Our results reveal an unconventional spin- and pressure-dependent pair-breaking effect and impose strong constraints on the pairing symmetry of these materials.4Kamihara, Y., Watanabe, T., Hirano, M., Hosono, H., Iron-based layered superconductor La[O12xFx]FeAs (x 5 0. 05-0. 12) with Tc 5 26 K (2008) J. Am. Chem. Soc., 130, p. 3296Rotter, M., Spin density wave anomaly at 140 K in the ternary iron arsenide BaFe2As2 (2008) Phys. Rev. B, 78, pp. 020503RIshida, K., Nakai, Y., Hosono, H., To what extent iron-pnictide new superconductors have been clarified: A progress report (2009) J. Phys. Soc. Japan, 78, p. 062001Hirschfeld, P.J., Korshunov, M.M., Mazin, I.I., Gap symmetry and structure of Fe-based superconductors (2011) Rep. Prog. Phys., 74, p. 124508Chubukov, A.V., Pairing mechanism in fe-based superconductors (2012) Annu. Rev. Cond. Mat. Phys., 3, p. 57Bittar, E.M., Co-substitution effects on the fe valence in the BaFe2As2 superconducting compound: A study of hard x-ray absorption spectroscopy (2011) Phys. Rev. Lett., 107, p. 267402Granado, E., Pressure and chemical substitution effects in the local atomic structure of BaFe2As2 (2011) Phys. Rev. B, 83, p. 184508Wadati, H., Elfimov, I., Sawatzky, G.A., Where are the extra d electrons in transition-metal-substituted iron pnictides? (2010) Phys. Rev. Lett., 105, p. 157004Ideta, S., Dependence of carrier doping on the impurity potential in transition-metal-substituted feas-based superconductors (2013) Phys. Rev. Lett., 110, p. 107007Berlijn, T., Lin, C.-H., Garber, W., Ku, W., Do transition-metal substitutions dope carriers in iron-based superconductors? (2012) Phys. Rev. Lett., 108, p. 207003Hin, Z.P., Haule, K., Kotliar, G., Kinetic frustration and the nature of the magnetic and paramagnetic states in iron pnictides and iron chalcogenides (2011) Nature Materials, 10, pp. 932a-935aRosa, P.F.S., Evolution of Eu21 spin dynamics in Ba12xEuxFe2As2 (2012) Phys. Rev. B, 86, p. 165131Rosa, P.F.S., (2014) Site Specific Spin Dynamics in BaFe2As2: Tuning the Ground State by Orbital Differentiation, , arxiv:1402. 2001v01Garitezi, T.M., Transport critical current measurements on a Cu-substituted BaFe2As2 superconductor (2014) J. Appl. Phys., 115, pp. 17D704Rosa, P.F.S., Pressure effects on magnetic pair-breaking in Mn- and Eusubstituted BaFe2As2 (2014) J. Appl. Phys., 115, pp. 17D702Thaler, A., Physical and magnetic properties of Ba(Fe12xMnx) 2As2 single crystals (2011) Phys. Rev. B, 84, p. 144528Et Al., A., Pressure effects on the electron-doped high Tc superconductor BaFe22xCoxAs2 (2008) J Phys. Cond. Mat., 20, p. 472201Et Al., D., Pressure versus concentration tuning of the superconductivity in Ba(Fe12xCox) 2As2 (2010) J. Phys. Soc. Japan, 79, p. 124705Yamaichi, S., Katagiri, T., Sasagawa, T., Uniaxial pressure effects on the transport properties in Ba(Fe12xCox) 2As2 single crystals (2013) Physica C, 494, pp. 62-64Canfield, P.C., Budko, S.L., Ni, N., Yan, J.Q., Kracher, A., Decoupling of the superconducting and magnetic/structural phase transitions in electron-doped BaFe2As2 (2009) Phys. Rev. B, 80, pp. 060501RKirshenbaum, K., Saha, S.R., Ziemak, S., Drye, T., Paglione, J., Universal pairbreaking in transition metal-substituted iron-pnictide superconductors (2012) Phys. Rev. B, 86, pp. 140505ROnari, S., Kontani, H., Violation of AndersonaƝ Theorem for the Sign-Reversing s-Wave State of Iron-Pnictide Superconductors (2009) Phys. Rev. Lett., 103, p. 177001Li, J., Superconductivity suppression of Ba0. 5K0. 5Fe222xMn2xAs2 single crystals by substitution of transition metal (M 5 Mn, Ru, Co, Ni, Cu, and Zn) (2012) Phys. Rev. B, 85, p. 214509Bang, Y., Choi, H.-Y., Won, H., Impurity effects on the s6-wave state of the ironbased superconductors (2009) Phys. Rev. B, 79, p. 054529Wang, Y., Kreisel, A., Hirschfeld, P.J., Mishra, V., Using controlled disorder to distinguish s6 and s11 gap structure in Fe-based superconductors (2013) Phys. Rev. B, 87, p. 094504Fernandes, R.M., Vavilov, M.G., Chubukov, A.V., Enhancement of Tc by disorder in underdoped iron pnictide superconductors (2012) Phys. Rev. B, 85, pp. 140512RNi, N., Temperature versus doping phase diagrams for Ba(Fe12xTMx) 2As2 (TM 5 Ni,Cu,Cu/Co) single crystals (2010) Phys. Rev. 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    Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

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    Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{6×10196\times 10^{19}eV}. The anisotropy was measured by the fraction of arrival directions that are less than 3.1∘3.1^\circ from the position of an active galactic nucleus within 75 Mpc (using the V\'eron-Cetty and V\'eron 12th12^{\rm th} catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is (38−6+7)(38^{+7}_{-6})%, compared with 2121% expected for isotropic cosmic rays. This is down from the early estimate of (69−13+11)(69^{+11}_{-13})%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201

    Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

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    Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic
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