13,027 research outputs found

    Modelling the relative velocities of isolated pairs of galaxies

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    We study the comoving relative velocities, v12, of model isolated galaxy pairs at z=0.5. For this purpose, we use the predictions from the GALFORM semi-analytical model of galaxy formation and evolution based on a Lambda cold dark matter cosmology consistent with the results from WMAP7. In real space, we find that isolated pairs of galaxies are predicted to form an angle t with the line-of-sight that is uniformily distributed as expected if the Universe is homogeneous and isotropic. We also find that isolated pairs of galaxies separated by a comoving distance between 1 and 3 Mpc/h are predicted to have =0. For galaxies in this regime, the distribution of the angle t is predicted to change minimally from real to redshift space, with a change smaller than 5% in . However, the distances defining the comoving regime strongly depends on the applied isolation criteria.Comment: 4 pages, 4 figures, SF2A 2013 Proceedin

    Comparison of |Q|=1 and |Q|=2 gauge-field configurations on the lattice four-torus

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    It is known that exactly self-dual gauge-field configurations with topological charge |Q|=1 cannot exist on the untwisted continuum 4-torus. We explore the manifestation of this remarkable fact on the lattice 4-torus for SU(3) using advanced techniques for controlling lattice discretization errors, extending earlier work of De Forcrand et. al. for SU(2). We identify three distinct signals for the instability of |Q|=1 configurations, and show that these manifest themselves early in the cooling process, long before the would-be instanton has shrunk to a size comparable to the lattice discretization threshold. These signals do not appear for our |Q|=2 configurations. This indicates that these signals reflect the truly global nature of the instability, rather than local discretization effects. Monte-Carlo generated SU(3) gauge field configurations are cooled to the self-dual limit using an O(a^4)-improved gauge action chosen to have small but positive O(a^6) errors. This choice prevents lattice discretization errors from destroying instantons provided their size exceeds the dislocation threshold of the cooling algorithm. Lattice discretization errors are evaluated by comparing the O(a^4)-improved gauge-field action with an O(a^4)-improved action constructed from the square of an O(a^4)-improved lattice field-strength tensor, thus having different O(a^6) discretization errors. The number of action-density peaks, the instanton size and the topological charge of configurations is monitored. We observe a fluctuation in the total topological charge of |Q|=1 configurations, and demonstrate that the onset of this unusual behavior corresponds with the disappearance of multiple-peaks in the action density. At the same time discretization errors are minimal.Comment: 12 pages, 9 figures, submitted to Phys. Rev.

    A new way of valorizing biomaterials: the use of sunflower protein for 1 a-tocopherol microencapsulation

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    Biopolymer based microparticles were efficiently prepared from sunflower protein (SP) wall material and a-tocopherol (T) active core using a spray-drying technique. Protein enzymatic hydrolysis and/or N-acylation were carried out to make some structural modifications to the vegetable protein. Native and hydrolyzed SP were characterized by Asymmetrical Flow Field-Flow Fractionation (AsFlFFF). Results of AsFlFFF confirmed that size of proteinic macromolecules was influenced by degree of hydrolysis. The effect of protein modifications and the influence of wall/core ratio on both emulsions and microparticle properties were evaluated. Concerning emulsion properties, enzymatic hydrolysis involved a decrease in viscosity, whereas acylation did not significantly affect emulsion droplet size and viscosity. Microparticles obtained with hydrolyzed SP wall material showed lower retention efficiency (RE) than native SP microparticles (62-80% and 93% respectively). Conversely, acylation of both hydrolyzed SP and native SP allowed a higher RE to be reached (up to 100%). Increasing T concentration increased emulsion viscosity, emulsion droplet size, microparticle size, and enhanced RE. These results demonstrated the feasibility of high loaded (up to 79.2% T) microparticles

    Uniportal robotic-assisted thoracic surgery for mediastinal tumors

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    Quantum Renormalization Group for 1 Dimensional Fermion Systems

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    Inspired by the superblock method of White, we introduce a simple modification of the standard Renormalization Group (RG) technique for the study of quantum lattice systems. Our method which takes into account the effect of Boundary Conditions(BC), may be regarded as a simple way for obtaining first estimates of many properties of quantum lattice systems. By applying this method to the 1-dimensional free and interacting fermion system, we obtain the ground state energy with much higher accuracy than the standard RG. We also calculate the density-density correlation function in the free-fermion case which shows good agreement with the exact result.Comment: LaTex file, 1 PS figur

    Spatially resolved kinematics in the central 1 kpc of a compact star-forming galaxy at z=2.3 from ALMA CO observations

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    We present high spatial resolution (FWHM\sim0.14'') observations of the CO(878-7) line in GDS-14876, a compact star-forming galaxy at z=2.3z=2.3 with total stellar mass of log(M/M)=10.9\log(M_{\star}/M_{\odot})=10.9. The spatially resolved velocity map of the inner r1r\lesssim1~kpc reveals a continous velocity gradient consistent with the kinematics of a rotating disk with vrot(r=1kpc)=163±5v_{\rm rot}(r=1\rm kpc)=163\pm5 km s1^{-1} and vrot/σ2.5v_{\rm rot}/\sigma\sim2.5. The gas-to-stellar ratios estimated from CO(878-7) and the dust continuum emission span a broad range, fgasCO=Mgas/M=1345%f^{\rm CO}_{\rm gas}=M_{\rm gas}/M_{\star}=13-45\% and fgascont=5067%f^{\rm cont}_{\rm gas}=50-67\%, but are nonetheless consistent given the uncertainties in the conversion factors. The dynamical modeling yields a dynamical mass oflog(Mdyn/M)=10.580.2+0.5\log(M_{\rm dyn}/M_{\odot})=10.58^{+0.5}_{-0.2} which is lower, but still consistent with the baryonic mass, log\log(Mbar_{\rm bar}= M_{\star} + MgasCO^{\rm CO}_{\rm gas}/M_{\odot})=11.0=11.0, if the smallest CO-based gas fraction is assumed. Despite a low, overall gas fraction, the small physical extent of the dense, star-forming gas probed by CO(878-7), 3×\sim3\times smaller than the stellar size, implies a strong concentration that increases the gas fraction up to fgasCO,1kpc85%f^{\rm CO, 1\rm kpc}_{\rm gas}\sim 85\% in the central 1 kpc. Such a gas-rich center, coupled with a high star-formation rate, SFR\sim 500 M_{\odot} yr1^{-1}, suggests that GDS-14876 is quickly assembling a dense stellar component (bulge) in a strong nuclear starburst. Assuming its gas reservoir is depleted without replenishment, GDS-14876 will quickly (tdepl27t_{\rm depl}\sim27 Myr) become a compact quiescent galaxy that could retain some fraction of the observed rotational support.Comment: Accepted for Publication in ApJL. Kinematic maps are shown in Figures 2 and

    Influencia del cereal y el nivel de inclusión de fibra en el pienso sobre la productividad en pollitas de 0 a 17 semanas de edad.

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    La fibra ha sido considerada como un diluyente del pienso en monogástricos con efectos negativos sobre consumo y la digestibilidad de los nutrientes (Jansen and Carré, 1985). Sin embargo, estudios recientes (Mateos et al., 2012) han mostrado que la inclusión de cantidades moderadas de fibra en el pienso podría mejorar tanto la digestibilidad de los nutrientes como el crecimiento de las aves. La inclusión de fibra en piensos para broilers podría incrementar el tiempo de retención de la digesta en la parte superior del tracto digestivo, estimulando el funcionamiento de la molleja (Hetland et al. 2005) y la producción de HCl en el proventrículo (Duke, 1986). Un descenso del pH de la molleja favorece la producción de pepsina e incrementa la solubilidad de las sales minerales (Jiménez-Moreno et al. 2009). Por lo tanto, la inclusión de cantidades adecuadas de fibra podría beneficiar el desarrollo del tracto gastrointestinal (Mateos et al., 2012). Sin embargo, la información disponible sobre los efectos beneficiosos de la fibra dietética en pollitas es escasa (Frikha et al., 2009). De hecho, los autores no han encontrado ningún estudio publicado sobre los efectos de la inclusión de fibra sobre el crecimiento de pollitas de 0 a 17 sem de edad. La influencia de fuentes de fibra tales como la cascarilla de avena, pulpa de remolacha (PRE) o cascarilla de soja sobre el desarrollo del tracto gastrointestinal ha sido bien estudiada en broilers (González-Alvarado el al., 2010). Sin embargo, la información disponible sobre el uso de paja de cereales (PCE) en dietas para avicultura es muy limitada; aun siendo una fuente de fibra abundante. La hipótesis del presente ensayo fue que la inclusión de cantidades moderadas de fibra en piensos de pollitas podría mejorar el rendimiento productivo con una mejora de la utilización de los nutrientes. El objetivo del presente trabajo fue estudiar el efecto de la inclusión de diversas fuentes de fibra a diferentes niveles en el pienso de pollitas sobre los rendimientos productivos de 0 a 17 sem de edad

    Influencia e la inclusión de fibra en el pienso sobre los rendimientos produtivos de pollitas rubias de 1 a 35 días de edad.

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    La fibra dietética representa la fracción indigestible de los ingredientes del pienso por lo que diluye el contenido en nutrientes del mismo (Rougière y Carré, 2010). Además, un aumento en el nivel de fibra del pienso puede reducir el consumo voluntario (Sklan et al., 2003), alterar el perfil de la flora gastrointestinal y aumentar la incidencia de procesos entéricos (Janssen and Carré, 1985). Sin embargo, estudios recientes muestran que la inclusión de ciertas fuentes de fibras a niveles adecuados podrían mejorar los rendimientos productivos y reducir la incidencia de problemas digestivos en aves (Mateos, 2012). En broilers, la inclusión de fibra adicional en el pienso mejoró la fisiología digestiva, aumentando el tamaño de la molleja, reduciendo el pH de la digesta de este órgano (Sacranie et al., 2012) y mejorando de los rendimientos productivos (González-Alvarado et al., 2010). Fuentes de fibra insoluble tales como la cascarilla de avena (CAV), la cascarilla de girasol (CGI) y la paja de cereales (PCE) podrían mejorar la fisiología del tracto gastrointestinal (TGI) y la digestibilidad de ciertos nutrientes cuando se incluyen en el pienso en cantidades moderadas (Hetland et al., 2003). Por otro lado, fuentes de fibra soluble, tal como la pulpa de remolacha (PRE), incrementan la viscosidad intestinal, lo que podría reducir el consumo de pienso (Jiménez-Moreno et al., 2010). Los autores no han encontrado estudio alguno sobre los efectos de la inclusión de fibra adicional en el pienso sobre los rendimientos productivos de pollitas comerciales. El objetivo del presente trabajo fue estudiar el efecto de incluir diversas fuentes de fibra a diferentes niveles en el pienso sobre los rendimientos productivos de pollitas de 1 a 35 d de edad

    GEC-ESTRO ACROP recommendations in skin brachytherapy

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    Purpose: The aim of this publication is to compile available literature data and expert experience regarding skin brachytherapy (BT) in order to produce general recommendations on behalf of the GEC-ESTRO Group. Methods: We have done an exhaustive review of published articles to look for general recommendations. Results: Randomized controlled trials, systemic reviews and meta-analysis are lacking in literature and there is wide variety of prescription techniques successfully used across the radiotherapy centers. BT can be delivered as superficial application (also called contact BT or plesiotherapy) or as interstitial for tumours thicker than 5 mm within any surface, including very irregular. In selected cases, particularly in tumours located within curved surfaces, BT can be advantageous modality from dosimetric and planning point of view when compared to external beam radiotherapy. The general rule in skin BT is that the smaller the target volume, the highest dose per fraction and the shortest overall length of treatment can be used. Conclusion: Skin cancer incidence is rising worldwide. BT offers an effective non-invasive or minimally invasive and relative short treatment that particularly appeals to elder and frail population
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