Anisotropic halo model

In the present work, we extend the classic halo model for the large-scale matter distribution including a triaxial model for the halo profiles and their alignments. In particular, we derive general expressions for the halo-matter cross correlation function. In addition, by numerical integration, we obtain instances of the cross-correlation function depending on the directions given by halo shape axes. These functions are called anisotropic cross-correlations. With the aim of comparing our theoretical results with the simulations, we compute averaged anisotropic correlations in cones with their symmetry axis along each shape direction of the centre halo. From these comparisons we characterise and quantify the alignment of dark matter haloes on the ΛCDM context by means of the presented anisotropic halo model. As our model requires multidimensional integral computation we implement a Monte Carlo method on GPU hardware which allows us to increase the precision of the results whereas it improves the performance of the computation.publishedVersio

New bases for a general definition for the moving preferred basis

One of the challenges of the Environment-Induced Decoherence (EID) approach is to provide a simple general definition of the moving pointer basis or moving preferred basis. In this letter we prove that the study of the poles that produce the decaying modes in non-unitary evolution, could yield a general definition of the relaxation, the decoherence times, and the moving preferred basis. These probably are the most important concepts in the theory of decoherence, one of the most relevant chapters of theoretical (and also practical) quantum mechanics. As an example we solved the Omnes (or Lee-Friedrich) model using our theory.Comment: 6 page

Noise models for superoperators in the chord representation

We study many-qubit generalizations of quantum noise channels that can be written as an incoherent sum of translations in phase space. Physical description in terms of the spectral properties of the superoperator and the action in phase space are provided. A very natural description of decoherence leading to a preferred basis is achieved with diffusion along a phase space line. The numerical advantages of using the chord representation are illustrated in the case of coarse-graining noise.Comment: 8 pages, 5 .ps figures (RevTeX4). Submitted to Phys. Rev. A. minor changes made, according to referee suggestion

On the coherence of synthetic turbulence generation methods

Synthetic turbulence generation methods have been extensively used by engineers and scientists in the past ten years in order to impose initial conditions in a wide range of turbulent flow problems. The interest in synthetic methods relies in the fact that reliability of methodologies such as large eddy simulation (LES) or direct numerical simulation (DNS) strongly depends on how well the developed turbulence is characterized, which generally leads to computationally expensive simulations. In this work the methodology known as “modified discretizing and synthesizing random flow generation” (MDSRFG) jointly with a LES method is analyzed for its use in the study of bluff body aerodynamics. A comparison with other generation techniques, that are closely related by their features and their conceptual origins, is presented with particular emphasis on the correct representation of the coherence of the velocity field. The resulting wind loads on the model, along with the statistical characteristics of the flow, show that the MDSRFG technique allows to represent a field of spatially correlated velocities correctly.Publicado en: Mecánica Computacional vol. XXXV, no. 18Facultad de Ingenierí

On the coherence of synthetic turbulence generation methods

Synthetic turbulence generation methods have been extensively used by engineers and scientists in the past ten years in order to impose initial conditions in a wide range of turbulent flow problems. The interest in synthetic methods relies in the fact that reliability of methodologies such as large eddy simulation (LES) or direct numerical simulation (DNS) strongly depends on how well the developed turbulence is characterized, which generally leads to computationally expensive simulations. In this work the methodology known as “modified discretizing and synthesizing random flow generation” (MDSRFG) jointly with a LES method is analyzed for its use in the study of bluff body aerodynamics. A comparison with other generation techniques, that are closely related by their features and their conceptual origins, is presented with particular emphasis on the correct representation of the coherence of the velocity field. The resulting wind loads on the model, along with the statistical characteristics of the flow, show that the MDSRFG technique allows to represent a field of spatially correlated velocities correctly.Publicado en: Mecánica Computacional vol. XXXV, no. 18Facultad de Ingenierí

Creation of unstable particles and decoherence in semiclassical cosmology

We consider a simple cosmological model in order to show the importance of unstable particle creation for the validity of the semiclassical approximation. Using the mathematical structure of rigged Hilbert spaces we show that particle creation is the seed of decoherence which enables the quantum to classical transition.Comment: latex file; 18 pages. Some changes have been added. To appear in Gen. Rel. and Gra

Digestibility of diets with flour fish silage for the growing of arawana (Osteoglossum bicirrhossum)

ABSTRACT Objective. The purpose of this research was to evaluate the digestibility of different nutritional and energy components of artificial diets containing flour fishsilage used in growing of arawana fingerlings (O. bicirrhossum). Materials and methods. 240 fingerlings distributed in 12 tanks with 20 fish per experimental unit were handled, in a completely randomized design made up of 4 treatments with three replicates, each with inclusions of 0 (0ESH), 10 (10ESH), 20(20ESH) and 30% flour fish silage (30ESH) of treatments T0, T1, T2 and T3 respectively; fromflour fish silagein order to formulate isoenergetic and isonitrogenous diets in the different treatments to avoid sources of miscalculation of the experimental variables. Results. High digestibility coefficients were observed in treatments T1 (10ESH) and T3 (30ESH). The protein, lipid and energy utilization ratios were greater than 60%, which shows the importance of including flour fish silage as a source of protein to improve the various growth parameters. Significant differences between treatments were found in the increase of length (p≤0.05), showing that the T1 was the best treatment with an average of 1.21±0.29 cm. Conclusions. According to the coefficients of digestibility, length increase and benefit – cost ratio, the best treatment was T1 (10ESH) used to feed arawana (O. bicirrhossum), during the growing period, demonstrating the economic and ecological advantages for utilization of this source of protein in aquaculture. RESUMEN Objetivo. Analizar la digestibilidad de los diferentes componentes nutricionales y energéticos en dietas balanceadas con niveles de harina de hidrolizado de vísceras de cachama en el alevinaje de arawana (O. bicirrhossum). Materiales y métodos. Se evaluaron 240 alevinos, distribuidos en 12 acuarios a razón de 1 animal/5 L. Se utilizó un diseño completamente al azar, conformado por cuatro tratamientos con tres réplicas cada uno, con inclusiones de 0 (0ESH), 10 (10ESH), 20 (20ESH) y 30% de extracto seco de hidrolizado de vísceras de cachama (30ESH) para los tratamientos T0, T1, T2 y T3 respectivamente; para evitar fuentes de error en el cálculo de las variables experimentales, se formularon dietas isoenergéticas e isonitrogenadas. Resultados. Se detectaron diferencias estadísticas significativas en el incremento de longitud (p≤0.05), indicando que el T1 (10ESH) es el mejor tratamiento con un promedio de talla de 1.21 ±0.29 cm, además, se obtuvieron coeficientes de digestibilidad superiores al 60% en los tratamientos T1 (10ESH) y T3 (30ESH) en lo referente a proteína, lípidos y Coeficientes de Utilización Energética (CUE); demostrando la importancia de incluir el extracto seco de hidrolizado de vísceras de cachama, en las dietas de los peces para mejorar las distintas variables zootécnicas, teniendo en cuenta la importancia acuariofílica de la especie. Conclusiones. De acuerdo con los coeficientes de digestibilidad, incrementos de longitud y la relación beneficio – costo el mejor tratamiento fue el T1 (10 ESH) en dietas de levante para O. bicirrhossum; demostrando las ventajas económicas y ecológicas de la incorporación de esta materia prima en la alimentación acuícola

Effect of molecular weight reduction by gamma irradiation on the antioxidant capacity of chitosan from lobster shells

AbstractThis study assessed the effect of molecular weight (MW) reduction by gamma irradiation on the antioxidant capacity of chitosan with potential application in the preservation of foodstuffs. Two batches of chitosan were obtained by heterogeneous chemical N-deacetylation of chitin from common lobster (Panulirus argus). Irradiation of chitosan was performed using a 60Co source and applying doses of 5, 10, 20 and 50 kGy with a dose rate of 10 kGy/h. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy was used to identify main chemical features of chitosan. The average viscosimetric MW was determined by the viscosimetric method while the deacetylation degree by a potentiometric method. Thermogravimetric analysis and differential scanning calorimetry were conducted to evaluate the thermal degradation behavior of the chitosan samples, both under nitrogen flow. The antioxidant activity of chitosan solutions at 1% (w/v) in lactic acid at 1% (v/v) and Tween 80 at 0.1% (v/v) was evaluated through the ABTS assay and scavenging of DPPH radical by chitosan. The increase of irradiation dose with 60Co until 50 kGy decreased significantly the MW of chitosan through the scission of glycosidic bonds without affecting its functional groups, while the DD (72–75 %) did not vary (p > 0.05). The AC of the chitosan solutions increased with the reduction of MW of chitosan by gamma irradiation

Test-retest and minimal detectable change in the assessment of muscle strength and muscle power in upper and lower extremity exercises in 9- to 14-year-old children

The prescription of maximal dynamic strength training in both adults and children is based on the evaluation of maximum strength, usually by one-repetition maximum tests (1RM). This study examined the test-retest reliability and the minimal detectable change (MDC) of the maximal force test and muscle power test. Forty-eight children (9–14 years old) completed two test–retest sessions that involved a one-repetition maximum (1RM) test and a muscle power test for leg extension (LE) and seated bench press (SBP). The MDC values of the 1RM test in the LE and SBP tests ranged from 7.35 to 11.34 kg and 6.84 to 7.92 kg, respectively. The MDC values of the muscle power test in the LE and SBP ranged from 30.32 to 63.20 Watt and 22.65 to 29.53 Watt, respectively. In children 9 to 14 years old, the increase of maximum strength along the growth curve was different in each muscle group studied. The repeatability of the 1RM test of the SBP was excellent (ICC 0.974) and was better than that of the LE (ICC, 0.954). The MDC of the 1RM test evaluation was 19.56% in the LE and 12.93% in the SBP.info:eu-repo/semantics/publishedVersio

Porphyrin-Based Metal-Organic Frameworks as Heterogeneous Catalysts in Oxidation Reactions

Porphyrin-based Metal-Organic Frameworks (Por-MOFs) constitute a special branch of the wide MOF family that has proven its own value and high potential in different applications. In this mini-review the application of these materials as catalysts in oxidation reactions is highlighted