Constraining Anisotropic Baryon Oscillations

We present an analysis of anisotropic baryon acoustic oscillations and elucidate how a mis-estimation of the cosmology, which leads to incorrect values of the angular diameter distance, d_A, and Hubble parameter, H, manifest themselves in changes to the monopole and quadrupole power spectrum of biased tracers of the density field. Previous work has focused on the monopole power spectrum, and shown that the isotropic "dilation" combination d_A^2/H is robustly constrained by an overall shift in the scale of the baryon feature. We extend this by demonstrating that the quadrupole power spectrum is sensitive to an anisotropic "warping" mode d_A H, allowing one to break the degeneracy between d_A and H. We describe a method for measuring this warping, explicitly marginalizing over the form of redshift space distortions. We verify this method on N-body simulations and estimate that d_A H can be measured with a fractional accuracy of ~ 3/sqrt(V) % where the survey volume is estimated in (Gpc/h)^3.Comment: 4 pages, 2 fig

Simultaneous Border-Collision and Period-Doubling Bifurcations

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

Direct measurement of the 14N(p,g)15O S-factor

We have measured the 14N(p,g)15O excitation function for energies in the range E_p = 155--524 keV. Fits of these data using R-matrix theory yield a value for the S-factor at zero energy of 1.64(17) keV b, which is significantly smaller than the result of a previous direct measurement. The corresponding reduction in the stellar reaction rate for 14N(p,g)15O has a number of interesting consequences, including an impact on estimates for the age of the Galaxy derived from globular clusters.Comment: 5 pages, 3 figures, submitted to Phys. Rev. Let

Synchronous vs Asynchronous Chain Motion in α-Synuclein Contact Dynamics

α-Synuclein (α-syn) is an intrinsically unstructured 140-residue neuronal protein of uncertain function that is implicated in the etiology of Parkinson’s disease. Tertiary contact formation rate constants in α-syn, determined from diffusion-limited electron-transfer kinetics measurements, are poorly approximated by simple random polymer theory. One source of the discrepancy between theory and experiment may be that interior-loop formation rates are not well approximated by end-to-end contact dynamics models. We have addressed this issue with Monte Carlo simulations to model asynchronous and synchronous motion of contacting sites in a random polymer. These simulations suggest that a dynamical drag effect may slow interior-loop formation rates by about a factor of 2 in comparison to end-to-end loops of comparable size. The additional deviations from random coil behavior in α-syn likely arise from clustering of hydrophobic residues in the disordered polypeptide

CO2 Kuznets Curve Revisited: From Cross-Sections to Panel Data Models

The Environmental Kuznets Curve (EKC) predicts that environmental degradation intensifies when per capita income increases and subsequently subsides after a certain income level is reached, resulting in an inverted U-shaped relationship. There is abundant literature on the topic that corroborates the existence of a positive income elasticity for environmental quality. However, results are controversial. We take the case of CO2, by comparing the results of the cross-sectional estimates with those derived from a panel approach. To this end, we use data from 182 countries during the period 1992-2011. We found that the EKC hypothesis is acceptable under both approaches, although the estimated turning points in cross-sections seem unreliable. Our application underlines the importance of adequately address central problems such as heterogeneity, structural breaks and spatial interaction. La curva de Kuznets (EKC) predice que la degradación medioambiental se intensifica inicialmente al aumentar la renta per cápita, para disminuir a continuación tras haber alcanzado cierto nivel de renta o turning point. Esta estructura se traduce en una relación en forma de U invertida entre ambas variables. Existe abundante literatura sobre el tema que corrobora la existencia de una elasticidad neta positiva para la calidad medioambiental. Sin embargo, los resultados son controvertidos. Analizamos el caso de CO2 comparando los resultados de las estimaciones transversales, con las derivadas de un enfoque panel. Para ello utilizamos datos de 182 países durante el periodo 1992-2011. Comprobamos que la hipótesis EKC resulta aceptable bajo ambos enfoques, aunque los turning point estimados en los cortes transversales son poco creíbles. Nuestra aplicación subraya la importancia de tratar adecuadamente problemas centrales como la heterogeneidad, las rupturas estructurales y la interacción espacial

Analysis of the capability of cork and cork agglomerates to absorb multiple compressive quasi-static loading cycles

Despite the higher specific mechanical properties and the lower density of polymeric foams, these materials present cumulative damage behaviour that implies in the second and successive impacts, their mechanical properties decrease drastically. However, cork and cork agglomerates have the ability to absorb multiple impacts so they could be a more suitable material in some products, such as bumpers and helmets. This article is focused on the study of five different cork agglomerates and a natural cork under four different maximum deformations subjected to four consecutive compression loading cycles. Main diagrams, such as the stress–strain, energy density and efficiency, and the variation in diverse parameters, such as the absorbed energy density and maximum efficiency, were investigated and compared with an expanded polystyrene foam

Removal of lead, mercury and nickel using the yeast Saccharomyces cerevisiae

Objective. In this study the biomass of the yeast Saccharomyces cerevisiae was used to remove lead, mercury and nickel in the form of ions dissolved in water. Materials and methods. Synthetic solutions were prepared containing the three heavy metals, which were put in contact with viable microorganisms at different conditions of pH, temperature, aeration and agitation. Results. Both individual variables and the interaction effects influenced the biosorption process. Throughout the experimental framework it was observed that the biomass of Saccharomyces cerevisiae removed a higher percentage of lead (86.4%) as compared to mercury and nickel (69.7 and 47.8% respectively). When the pH was set at a value of 5 the effect was positive for all three metals. Conclusions. pH was the variable that had a greater influence on the biosorption of lead on the biomass of Saccharomyces cerevisiae. The affinity of the heavy metals for the biomass followed the order Pb>Hg>Ni

Configuration Complexities of Hydrogenic Atoms

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

Low-pH cement mortar-bentonite perturbations in a small-scale pilot laboratory experiment

This article has been published in a revised form in Clay Minerals [http://doi.org/10.1180/clm.2018.16]. This version is free to view and download for private research and study only. Not for re-distribution, re-sale or use in derivative worksA novel method to perform small-scale laboratory experiments that reproduce concrete–bentonite and concrete–groundwater interactions has been developed. Such interfaces will prevail in engineered barrier systems used for isolation of nuclear waste. With the goal of optimizing the experimental method, this work has analysed the geochemical interaction of distilled water, low-pH cement mortar and FEBEX-bentonite for 75 days. Limited but evident reactivity between the materials was observed, mainly decalcification in cement mortar, carbonation at the interface with bentonite and Mg enrichment in bentonite. These results are consistent with the state-of-the-art literature and were used to validate this small-scale pilot laboratory experiment to establish the basis for further studies comparing the behaviour of different buffer and cement materialsThe research leading to these results has received funding from the European Union's Horizon 2020 Research and Training 305 Programme of the EURATOM (H2020-NFRP-2014/2015) under grant agreement n° 662147 (CEBAMA