2,942 research outputs found

    How BAO measurements can fail to detect quintessence

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    We model the nonlinear growth of cosmic structure in different dark energy models, using large volume N-body simulations. We consider a range of quintessence models which feature both rapidly and slowly varying dark energy equations of state, and compare the growth of structure to that in a universe with a cosmological constant. The adoption of a quintessence model changes the expansion history of the universe, the form of the linear theory power spectrum and can alter key observables, such as the horizon scale and the distance to last scattering. The difference in structure formation can be explained to first order by the difference in growth factor at a given epoch; this scaling also accounts for the nonlinear growth at the 15% level. We find that quintessence models which feature late (z<2)(z<2), rapid transitions towards w=1w=-1 in the equation of state, can have identical baryonic acoustic oscillation (BAO) peak positions to those in Λ\LambdaCDM, despite being very different from Λ\LambdaCDM both today and at high redshifts (z1000)(z \sim 1000). We find that a second class of models which feature non-negligible amounts of dark energy at early times cannot be distinguished from Λ\LambdaCDM using measurements of the mass function or the BAO. These results highlight the need to accurately model quintessence dark energy in N-body simulations when testing cosmological probes of dynamical dark energy.Comment: 10 pages, 7 figures, to appear in the Invisible Univers International Conference AIP proceedings serie

    On Hirschman and log-Sobolev inequalities in mu-deformed Segal-Bargmann analysis

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    We consider a deformation of Segal-Bargmann space and its transform. We study L^p properties of this transform and obtain entropy-entropy inequalities (Hirschman) and entropy-energy inequalities (log-Sobolev) that generalize the corresponding known results in the undeformed theory.Comment: 42 pages, 3 figure

    Levels of rare earth elements in hair from a group of young Spanish adults (aged 20-24 years).

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    The Publisher's final version can be found by following the DOI link.The rapid agricultural, medical and industrial development is occurring on a global scale and bringing with emerging environmental threats for humans. Contamination by rare earth elements (REE) has emerged as a public health concern due to their numerous applications in the current industry. However, little is known about their toxicological effects despite they can accumulate in different organs including brain and bone. To determine the exposure to these contaminants in a young Spanish population, scalp hair samples were collected in 37 young adults (20 to 24 years-old; 28 female and 9 male) from different towns in the Community of Madrid (Spain). Despite being controversial, human hair could be an appropriate tool to determine environmental exposure to inorganic metal contaminants and to estimate the chemical burden in the individual. Lanthanum (La), cerium (Ce), praseodymium (Pr), erbium (Er) and gadolinium (Gd) were analysed in these samples by ICP-MS following appropriate methodologies. The limits of detection were (in ng/g): La (1.87), Ce (4.29), Pr (0.47), Er (0.06) and Gd (0.24 ng/g). Gd was detected only in one of the monitored samples (2.66 ng/g). The concentrations were as follow (median and percentiles are provided in ng/g): La 5.30 (4.22, 7.13), Ce 11.18 (8.97, 15.45), Pr 1.28 (1.04, 1.72) and Er 0.19 (0.14, 0.28). In general, the presence of these metals in the Spanish group’s hair monitored were lower than those reported in environmentally exposed groups, which may indicate that the studied group would have a low exposure to REE. None of these elements showed influence due to sex, although slightly higher levels were observed for La (5.57 vs. 5.17 ng/g), Pr (1.40 vs. 1.27 ng/g), Nd (2.48 vs. 2.29 ng/g) and Er (0.21 vs. 0.19 ng/g) in men’s hair and in women’s hair for Ce (11.58 vs 10.30 ng/g). Despite is unclear, our results would be in agreement with those studies that have suggested that men may be more sensitive to REE than women

    Simultaneous Border-Collision and Period-Doubling Bifurcations

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    We unfold the codimension-two simultaneous occurrence of a border-collision bifurcation and a period-doubling bifurcation for a general piecewise-smooth, continuous map. We find that, with sufficient non-degeneracy conditions, a locus of period-doubling bifurcations emanates non-tangentially from a locus of border-collision bifurcations. The corresponding period-doubled solution undergoes a border-collision bifurcation along a curve emanating from the codimension-two point and tangent to the period-doubling locus here. In the case that the map is one-dimensional local dynamics are completely classified; in particular, we give conditions that ensure chaos.Comment: 22 pages; 5 figure

    MOPREDAScentury: a long-term monthly precipitation grid for the Spanish mainland

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    This article describes the development of a monthly precipitation dataset for the Spanish mainland (western Mediterranean basin), covering the period between December 1915 and December 2020. The dataset combines ground observational data from the National Climate Data Bank (NCDB) of the Spanish national climate and weather service (AEMET) and new data rescued from meteorological yearbooks published prior to 1951 that was never incorporated into the NCDB. The yearbooks data represented a significant improvement of the dataset, as it almost doubled the number of weather stations available during the first decades of the 20th century, the period when the dataset was more scarce. The final dataset contains records from 11,312 stations, although the number of stations with data in a given month varies largely between 674 in 1939 and a maximum of 5,234 in 1975. Spatial interpolation was used on the resulting dataset to create monthly precipitation grids. The process involved a two-stage process: estimation of the probability of zero-precipitation (dry month), and estimation of precipitation magnitude. Interpolation was carried out using universal kriging, using anomalies (ratios with respect to the 1961&ndash;2000 monthly climatology) as dependent variable and several geographic variates as independent variables. Cross-validation results showed that the resulting grids are spatially and temporally unbiased, although the mean error and the variance deflation effect are highest during the first decades of the 20th century, when the observational dataset was more scarce. The dataset is available at https://doi.org/10.20350/digitalCSIC/15136 under an open license, and can be cited as Beguer&iacute;a et al. (2023).</p

    MOPREDAS_century database and precipitation trends in mainland Spain, 1916–2020

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    Due to its geographical location in the western Mediterranean region, the Iberian Peninsula involves a challenge for current climatic conditions and future projections. In this study we analysed monthly precipitation trends over mainland Spain from 1916 to 2020 by using the new MOPREDAS_century database. This database combines information from the Spanish Meteorological Agency's archives, as well as data retrieved from Annual Summaries between 1916 and 1950. A combination of both sources produced the largest amount of original information ever collected and researched in mainland Spain between 1916 and 2020

    Conductance Distributions in Random Resistor Networks: Self Averaging and Disorder Lengths

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    The self averaging properties of conductance gg are explored in random resistor networks with a broad distribution of bond strengths P(g)\simg^{\mu-1}. Distributions of equivalent conductances are estimated numerically on hierarchical lattices as a function of size LL and distribution tail parameter μ\mu. For networks above the percolation threshold, convergence to a Gaussian basin is always the case, except in the limit μ\mu --> 0. A {\it disorder length} ξD\xi_D is identified beyond which the system is effectively homogeneous. This length diverges as ξDμν\xi_D \sim |\mu|^{-\nu} (ν\nu is the regular percolation correlation length exponent) as μ\mu-->0. This suggest that exactly the same critical behavior can be induced by geometrical disorder and bu strong bond disorder with the bond occupation probability ppμ\mu. Only lattices at the percolation threshold have renormalized probability distribution in a {\it Levy-like} basin. At the threshold the disorder length diverges at a vritical tail strength μc\mu_c as μμcz|\mu-\mu_c|^{-z}, with z=3.2±0.1z=3.2\pm 0.1, a new exponent. Critical path analysis is used in a generalized form to give form to give the macroscopic conductance for lattice above pcp_c.Comment: 16 pages plain TeX file, 6 figures available upon request.IBC-1603-01

    Configuration Complexities of Hydrogenic Atoms

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    The Fisher-Shannon and Cramer-Rao information measures, and the LMC-like or shape complexity (i.e., the disequilibrium times the Shannon entropic power) of hydrogenic stationary states are investigated in both position and momentum spaces. First, it is shown that not only the Fisher information and the variance (then, the Cramer-Rao measure) but also the disequilibrium associated to the quantum-mechanical probability density can be explicitly expressed in terms of the three quantum numbers (n, l, m) of the corresponding state. Second, the three composite measures mentioned above are analytically, numerically and physically discussed for both ground and excited states. It is observed, in particular, that these configuration complexities do not depend on the nuclear charge Z. Moreover, the Fisher-Shannon measure is shown to quadratically depend on the principal quantum number n. Finally, sharp upper bounds to the Fisher-Shannon measure and the shape complexity of a general hydrogenic orbital are given in terms of the quantum numbers.Comment: 22 pages, 7 figures, accepted i

    Analysis of antenal sensilla patterns of Rhodnius prolixus from Colombia and Venezuela

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    Antennal sensilla patterns were used to analyze population variation of domestic Rhodnius prolixus from six departments and states representing three biogeographical regions of Colombia and Venezuela. Discriminant analysis of the patterns of mechanoreceptors and of three types of chemoreceptors on the pedicel and flagellar segments showed clear differentiation between R. prolixus populations east and west of the Andean Cordillera. The distribution of thick and thin-walled trichoids on the second flagellar segment also showed correlation with latitude, but this was not seen in the patterns of other sensilla. The results of the sensilla patterns appear to be reflecting biogeographic features or population isolation rather than characters associated with different habitats and lend support to the idea that domestic R. prolixus originated in the eastern region of the Andes.Fil: Esteban, Lyda. Universidad Industrial de Santander; ColombiaFil: Angulo, Víctor Manuel. Universidad Industrial de Santander; ColombiaFil: Dora Feliciangeli, M.. Universidad de Carabobo; VenezuelaFil: Catala, Silvia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentin
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