Filtering techniques for the detection of Sunyaev-Zel'dovich clusters in multifrequency CMB maps

The problem of detecting Sunyaev-Zel'dovich (SZ) clusters in multifrequency CMB observations is investigated using a number of filtering techniques. A multifilter approach is introduced, which optimizes the detection of SZ clusters on microwave maps. An alternative method is also investigated, in which maps at different frequencies are combined in an optimal manner so that existing filtering techniques can be applied to the single combined map. The SZ profiles are approximated by the circularly-symmetric template $\tau (x) = [1 +(x/r_c)^2]^{-\lambda}$, with $\lambda \simeq \tfrac{1}{2}$ and $x\equiv |\vec{x}|$, where the core radius $r_c$ and the overall amplitude of the effect are not fixed a priori, but are determined from the data. The background emission is modelled by a homogeneous and isotropic random field, characterized by a cross-power spectrum $P_{\nu_1 \nu_2}(q)$ with $q\equiv |\vec{q}|$. The filtering methods are illustrated by application to simulated Planck observations of a $12.8^\circ \times 12.8^\circ$ patch of sky in 10 frequency channels. Our simulations suggest that the Planck instrument should detect $\approx 10000$ SZ clusters in 2/3 of the sky. Moreover, we find the catalogue to be complete for fluxes $S > 170$ mJy at 300 GHz.Comment: 12 pages, 7 figures; Corrected figures. Submitted to MNRA

CMB power spectrum estimation and map reconstruction with the Expectation - Maximization algorithm

We apply the iterative Expectation-Maximization algorithm (EM) to estimate the power spectrum of the CMB from multifrequency microwave maps. In addition, we are also able to provide a reconstruction of the CMB map. By assuming that the combined emission of the foregrounds plus the instrumental noise is Gaussian distributed in Fourier space, we have simplified the EM procedure finding an analytical expression for the maximization step. By using the simplified expression the CPU time can be greatly reduced. We test the stability of our power spectrum estimator with realistic simulations of Planck data, including point sources and allowing for spatial variation of the frequency dependence of the Galactic emissions. Without prior information about any of the components, our new estimator can recover the CMB power spectrum up to scales l~1500 with less than 10% error. This result is significantly improved if the brightest point sources are removed before applying our estimator. In this way, the CMB power spectrum can be recovered up to l~1700 with 10% error and up to l~2100 with 50% error. This result is very close to the one that would be obtained in the ideal case of only CMB plus white noise, for which all our assumptions are satisfied. Moreover, the EM algorithm also provides an straightforward mechanism to reconstruct the CMB map. The recovered cosmological signal shows a high degree of correlation (r = 0.98) with the input map and low residuals.Comment: Final version (minor changes). 10 pages, 6 figures, MNRAS accepte

Vortex solutions in the noncommutative torus

Vortex configurations in the two-dimensional torus are considered in noncommutative space. We analyze the BPS equations of the Abelian Higgs model. Numerical solutions are constructed for the self-dual and anti-self dual cases by extending an algorithm originally developed for ordinary commutative space. We work within the Fock space approach to noncommutative theories and the Moyal-Weyl connection is used in the final stage to express the solutions in configuration space.Comment: 18 pages, 5 figure

Isotropic Wavelets: a Powerful Tool to Extract Point Sources from CMB Maps

It is the aim of this paper to introduce the use of isotropic wavelets to detect and determine the flux of point sources appearing in CMB maps. The most suited wavelet to detect point sources filtered with a Gaussian beam is the Mexican Hat. An analytical expression of the wavelet coefficient obtained in the presence of a point source is provided and used in the detection and flux estimation methods presented. For illustration the method is applied to two simulations (assuming Planck Mission characteristics) dominated by CMB (100 GHz) and dust (857 GHz) as these will be the two signals dominating at low and high frequency respectively in the Planck channels. We are able to detect bright sources above 1.58 Jy at 857 GHz (82% of all sources) and above 0.36 Jy at 100 GHz (100% of all) with errors in the flux estimation below 25%. The main advantage of this method is that nothing has to be assumed about the underlying field, i.e. about the nature and properties of the signal plus noise present in the maps. This is not the case in the detection method presented by Tegmark and Oliveira-Costa 1998. Both methods are compared producing similar results.Comment: 6 pages. Accepted for publication in MNRA

Non-Abelian Vortices on the Torus

We study periodic arrays of non-Abelian vortices in an $SU(N) \times U(1)$ gauge theory with $N_f$ flavors of fundamental matter multiplets. We carefully discuss the corresponding twisted boundary conditions on the torus and propose an ansatz to solve the first order Bogomolnyi equations which we find by looking to a bound of the energy. We solve the equations numerically and construct explicit vortex solutions

A Bayesian non-parametric method to detect clusters in Planck data

We show how one may expect a significant number of SZ detections in future Planck data without any of the typical assumptions needed in present component separation methods, such as about the power spectrum or the frequency dependence of any of the components, circular symmetry or a typical scale for the clusters. We reduce the background by subtracting an estimate of the point sources, dust and CMB. The final SZE map is estimated in Fourier space. The catalogue of returned clusters is complete above flux 200 mJy (353 GHz) while the lowest flux reached by our method is about 70 mJy (353 GHz). We predict a large number of detections (about 9000) in 4/5 of the sky. This large number of SZ detections will allow a robust and consistent analysis of the evolution of the cluster population with redshift and will have important implications for determining the best cosmological model.Comment: MNRAS accepted. Major changes made to match accepted version. Colour figures attached as GIF files. 15 pages and 12 figures. High resolution colour pictures can be obtained on request from the authors ([email protected]

The mechanical hybrid vehicle: an investigation of a flywheel-based vehicular regenerative energy capture system

Capturing braking energy by regeneration into an onboard energy storage unit offers the potential to reduce significantly the fuel consumption of vehicles. A common technique is to generate electricity in the motors of a hybrid electric vehicle when braking, and to use this to charge an onboard electrochemical battery. However, such batteries are costly, bulky, and generally not amenable to fast charging as this affects battery life and capacity. In order to overcome these problems, a mechanical energy storage system capable of accepting and delivering surges of power is proposed and investigated. A scale physical model of the system, based around a flywheel, a planetary gear set, and a brake, was built and operated in a laboratory. Tests showed that the proposed system could be used to store and provide braking energy between a flywheel and a vehicle, the latter emulated by an air-drag dynamometer. This validated the operating principle of the system and its computational model. Further, a computational analysis of a full-size vehicle incorporating the mechanical energy storage system was conducted. The results showed that the utilization of this system in a vehicle, when compared with a conventional vehicle, led to reductions in emissions and fuel consumption

Efecto del manejo y del temperamento animal sobre indicadores de calidad de la carne bovina

The aim of this research was to study the effect of different handling conditions on physiological stress indicators and meat quality of beef cattle by studying animals with different temperaments. Forty animals classified by their temperament (calm and disturbed) were used. They were fed on pastures and finished with a mixed diet of corn grain and pasture. Biochemical indicators of animal stress were measured at slaughter (packed cell volume -PCV-, proteins, glucose, creatinine, alkaline phosphatase -APactivity, cortisol, insulin, glycogen). Also, ultimate pH and instrumental colour were chosen as meat quality markers. Animal temperament showed a significantly increase (p<0.05) on PCV levels and a significantly (p<0.05) decrease on muscle glycogen. Besides, levels of plasma glucose and total proteins showed significant (p<0.05) differences associated to management applied. Meat quality markers (pH and colour) did not show significant differences according to handling conditions or temperament. Mean cortisol levels at the exsanguination time were significantly higher (p<0.05) than the values obtained one week prior to slaughter, which suggests an important effect of stress associated to slaughter procedures. It would be interesting to focus attention on the assessment of acute stress at abattoir, in order to improve handling protocols, and therefore to assure meat quality in Argentinean beef production systems.El objetivo del presente trabajo fue estudiar el efecto de diferentes condiciones de manejo sobre indicadores fisiológicos de estrés y de calidad de carne en bovinos con temperamentos contrastantes. Se utilizaron cuarenta animales clasificados como calmos y excitables. Los mismos fueron alimentados inicialmente a base de pasturas y terminados con una dieta mixta de grano de maíz y pasturas. Se dosaron indicadores bioquímicos de estrés (hematocrito, proteínas plasmáticas, glucosa, creatinina, actividad fosfatasa alcalina, cortisol, insulina, contenido muscular de glucógeno). Como indicadores de calidad de carne se midieron el pH de 24 h y color instrumental. El temperamento animal demostró un incremento significativo (p<0,05) en los niveles de hematocrito y con una disminución significativa (p<0,05) del glucógeno muscular. Los niveles de glucemia y de proteínas totales mostraron modificaciones significativas (p<0,05) asociadas con el manejo. El incremento (p<0,05) en los niveles plasmáticos de cortisol durante la faena, independientemente del tratamiento o el temperamento animal, sugiere un importante efecto estresor por parte del proceso de faena. Sería interesante centrar la atención en el estudio del estrés agudo, a fin de mejorar protocolos de manejo animal, y consecuentemente, optimizar la calidad de la carne asociada en los sistemas de producción de Argentina.Fil: Pighin, D. G.. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Agroindustrias. Instituto de Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Moron; ArgentinaFil: Davies, P.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Grigioni, Gabriela Maria. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Agroindustrias. Instituto de Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Moron; ArgentinaFil: Pazos, A. A.. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Agroindustrias. Instituto de Tecnología de Alimentos; Argentina. Universidad de Moron; ArgentinaFil: Ceconi, I.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Mendez, Diego Eduardo. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Buffarini, M.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Sancho, A.. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Agroindustrias. Instituto de Tecnología de Alimentos; Argentina. Universidad de Moron; ArgentinaFil: Gonzalez, Claudia Beatriz. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Agroindustrias. Instituto de Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentin

Satellite galaxies in groups in the CIELO Project I: Gas removal from galaxies and its re-distribution in the intragroup medium

We study the impact of the environment on galaxies as they fall in and orbit in the potential well of a Local Group (LG) analogue, following them with high cadence. The analysis is performed on eight disc satellite galaxies from the CIELO suite of hydrodynamical simulations. All galaxies have stellar masses within the range [10 8.1 -109.56 ] M⊙h-1. We measure tidal torques, ram pressure, and specific star formation rates (sSFRs) as a function of time, and correlate them with the amount of gas lost by satellites along their orbits. Stronger removal episodes occur when the disc plane is oriented perpendicular to the direction of motion. More than one peripassage is required to significantly modify the orientations of the discs with respect to the orbital plane. The gas removed during the interaction with the central galaxies may also be found opposite to the direction of motion, depending on the orbital configuration. Satellites are not totally quenched when the galaxies reach their first peripassage and continue forming about 10 per cent of the final stellar mass after this event. The fraction of removed gas is found to be the product of the joint action of tidal torque and ram pressure, which can also trigger new star formation activity and subsequent supernova feedback.Fil: Rodríguez Moncada, Silvio Ribamar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Garcia Lambas, Diego Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Padilla, Nelson David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Tissera, P.. Pontificia Universidad Católica de Chile; ChileFil: Bignone, Lucas Axel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Dominguez Tenreiro, Rosa. Pontificia Universidad Católica de Chile; ChileFil: Gonzalez, R.. Pontificia Universidad Católica de Chile; ChileFil: Pedrosa, Susana Elizabeth. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Effects of hyperoxia exposure on metabolic markers and gene expression in 3T3- L1 adipocytes

Adipose tissue often becomes poorly oxygenated in obese subjects. This feature may provide cellular mechanisms involving chronic inflammation processes such as the release of proinflammatory cytokines and macrophage infiltration. In this context, the purpose of the present study was to determine whether a hyperoxia exposure on mature adipocytes may influence the expression of some adipokines and involve favorable changes in specific metabolic variables. 3T3-L1 adipocytes (14 days differentiated) were treated with 95% oxygen for 24 h. Cell viability, intra and extracellular reactive oxygen especies (ROS) content, glucose uptake and lactate and glycerol concentrations were measured in the culture media. Also, mRNA levels of HIF-1[alfa], leptin, IL-6, MCP-1, PPAR-[gamma], adiponectin, and ANGPTL-4 were analyzed. Hyperoxia treatment increased intra and extracellular ROS content, reduced glucose uptake and lactate release and increased glucose release. It also led to an upregulation of the expression of IL-6, MCP-1 and PPAR-[gamma], while ANGPTL4 was downregulated in the hyperoxia group with respect to control. The present data shows that hyperoxia treatment seems to provoke an inflammatory response due to the release of ROS and the upregulation of pro-inflammatory adipokines, such as IL-6 and MCP-1. On the other hand, hyperoxia may have an indirect effect on the improvement of insulin sensitivity, due to the upregulation of PPAR-[gamma] gene expression as well as a possible modulation of both glucose and lipid metabolic markers. To our knownledge, this is the first study analyzing the effect of hyperoxia in 3T3-L1 adipocytes