Composite Boson Mapping for Lattice Boson Systems

We present a canonical mapping transforming physical boson operators into quadratic products of cluster composite bosons that preserves matrix elements of operators when a physical constraint is enforced. We map the 2D lattice Bose-Hubbard Hamiltonian into $2\times 2$ composite bosons and solve it at mean field. The resulting Mott insulator-superfluid phase diagram reproduces well Quantum Monte Carlo results. The Higgs boson behavior along the particle-hole symmetry line is unraveled and in remarkable agreement with experiment. Results for the properties of the ground and excited states are competitive with other state-of-the-art approaches, but at a fraction of their computational cost. The composite boson mapping here introduced can be readily applied to frustrated many-body systems where most methodologies face significant hurdles.Comment: 8 pages, 4 figure

Composite fermion-boson mapping for fermionic lattice models

We present a mapping of elementary fermion operators onto a quadratic form of composite fermionic and bosonic operators. The mapping is an exact isomorphism as long as the physical constraint of one composite particle per cluster is satisfied. This condition is treated on average in a composite particle mean-field approach, which consists of an ansatz that decouples the composite fermionic and bosonic sectors. The theory is tested on the one- and two-dimensional Hubbard models. Using a Bogoliubov determinant for the composite fermions and either a coherent or Bogoliubov state for the bosons, we obtain a simple and accurate procedure for treating the Mott insulating phase of the Hubbard model with mean-field computational cost

Estudio mineralógico, textural y físico-mecánico de morteros de cal hidráulica curados en distintas condiciones de humedad relativa

This work focuses on the chemical-mineralogical, textural and physical-mechanical properties of hydraulic lime mortars made with siliceous and calcareous aggregate. Mortars were cured at 60% and 90% of relative humidity, so as to assess the variability of mortar petrophysical properties in the hardened state due to the moisture conditions. The final aim was to determine the most adequate moisture conditions to be maintained during application and hardening of hydraulic mortars intended for repair interventions. We found out that using a calcareous aggregate and curing mortar at 90% of relative humidity give place to better textural and mechanical properties. However, these characteristics mostly depend on the maximum size of the aggregate grains, which should be smaller than 6 mm, in order to avoid the occurrence of mechanical discontinuities in the mortar.En este trabajo se han estudiado las propiedades químico-mineralógicas, texturales y físico-mecánicas de morteros de cal hidráulica elaborados con áridos silíceo y calcítico. Estos morteros se han curado al 60% y 90% de humedad relativa, con el fin de evaluar las eventuales diferencias en las propiedades petrofísicas de los morteros una vez endurecidos y así establecer cuál de los dos ambientes es recomendable durante la aplicación y fraguado de morteros de cal hidráulica destinados a obras de restauración. Se ha encontrado que el uso de un árido de composición calcítica y el curado al 90% de humedad relativa dan lugar a morteros hidráulicos con mejores características texturales y propiedades mecánicas. De todas formas, estas características dependen principalmente del tamaño máximo del árido empleado, que debería ser inferior a 6 mm para evitar discontinuidades mecánicas en el mortero

Estudio mineralógico, textural y físico-mecánico de morteros de cal hidráulica curados en distintas condiciones de humedad relativa

This work focuses on the chemical-mineralogical, textural and physical-mechanical properties of hydraulic lime mortars made with siliceous and calcareous aggregate. Mortars were cured at 60% and 90% of relative humidity, so as to assess the variability of mortar petrophysical properties in the hardened state due to the moisture conditions. The final aim was to determine the most adequate moisture conditions to be maintained during application and hardening of hydraulic mortars intended for repair interventions. We found out that using a calcareous aggregate and curing mortar at 90% of relative humidity give place to better textural and mechanical properties. However, these characteristics mostly depend on the maximum size of the aggregate grains, which should be smaller than 6 mm, in order to avoid the occurrence of mechanical discontinuities in the mortar.En este trabajo se han estudiado las propiedades químico-mineralógicas, texturales y físico-mecánicas de morteros de cal hidráulica elaborados con áridos silíceo y calcítico. Estos morteros se han curado al 60% y 90% de humedad relativa, con el fin de evaluar las eventuales diferencias en las propiedades petrofísicas de los morteros una vez endurecidos y así establecer cuál de los dos ambientes es recomendable durante la aplicación y fraguado de morteros de cal hidráulica destinados a obras de restauración. Se ha encontrado que el uso de un árido de composición calcítica y el curado al 90% de humedad relativa dan lugar a morteros hidráulicos con mejores características texturales y propiedades mecánicas. De todas formas, estas características dependen principalmente del tamaño máximo del árido empleado, que debería ser inferior a 6 mm para evitar discontinuidades mecánicas en el mortero.This study was financially supported by the Spanish research group RNM179 of the Junta de Andalucía, by the research project MAT-2012-34473 and by the Institute of Conservation and Restoration of Cultural Heritage of the CICOP foundation (ICON-CICOP)

Accurate placement of epiescleral plaque in brachytherapy of choroideal melanoma

Salvadó Jassans, JosepPla general de l'obra: A Lluís Millet. Es veu la figura, en bronze, del músic i fundador de l'Orfeó Català, en el gest de dirigir. Està situada a l'exterior del Palau de la Música Catalana

Constructor paralelo de planificaciones

Scheduling es un área activa de investigación en Inteligencia Artificial Aplicada. El interés en esta área es planificar adecuadamente la asignación de un número limitado de recursos a determinadas tareas que se deben desarrollar en el tiempo. Existen un número de técnicas heurísticas que han realizado contribuciones notables al problema de scheduling, entre ellas los algoritmos genéticos y otras variantes de la Computación Evolutiva. Estos algoritmos tienen la capacidad de descubrir planificaciones cercanas a las óptimas mucho más rápido debido a su paralelismo implícito. Varias implementaciones ya realizadas en esta dirección muestran que los algoritmos genéticos trabajan mejor cuando en la representación del cromosoma que utilizan se incorpora conocimiento específico del problema de modo tal que permita trabajar con operadores de recombinación avanzados. La elección de este tipo de representación indirecta del cromosoma requiere de un decodificador o "schedulers builder ", el cual transforme la representación del cromosoma en una planificación legal. En otras palabras los schedule builder deben garantizar la factibilidad y consistencia de cada planificación.Eje: Procesamiento concurrente, paralelo y distribuido. Procesamiento de imágenes.Red de Universidades con Carreras en Informática (RedUNCI

Constructor paralelo de planificaciones

Scheduling es un área activa de investigación en Inteligencia Artificial Aplicada. El interés en esta área es planificar adecuadamente la asignación de un número limitado de recursos a determinadas tareas que se deben desarrollar en el tiempo. Existen un número de técnicas heurísticas que han realizado contribuciones notables al problema de scheduling, entre ellas los algoritmos genéticos y otras variantes de la Computación Evolutiva. Estos algoritmos tienen la capacidad de descubrir planificaciones cercanas a las óptimas mucho más rápido debido a su paralelismo implícito. Varias implementaciones ya realizadas en esta dirección muestran que los algoritmos genéticos trabajan mejor cuando en la representación del cromosoma que utilizan se incorpora conocimiento específico del problema de modo tal que permita trabajar con operadores de recombinación avanzados. La elección de este tipo de representación indirecta del cromosoma requiere de un decodificador o "schedulers builder ", el cual transforme la representación del cromosoma en una planificación legal. En otras palabras los schedule builder deben garantizar la factibilidad y consistencia de cada planificación.Eje: Procesamiento concurrente, paralelo y distribuido. Procesamiento de imágenes.Red de Universidades con Carreras en Informática (RedUNCI

Activation of the Receptor Tyrosine Kinase, RET, improves long-term Hematopoietic Stem Cell outgrowth and potency

Expansion of Human Hematopoietic Stem Cells (HSCs) is a rapidly advancing field showing great promise for clinical applications. Recent evidence has implicated the nervous system and glial family ligands (GFLs) as potential drivers of hematopoietic survival and self-renewal in the bone marrow niche, but how to apply this to HSC maintenance and expansion is yet to be explored. We demonstrate a role for the GFL receptor, RET, at the cell surface of HSCs, in mediating sustained cellular growth, resistance to stress and improved cell survival throughout in vitro expansion. HSCs treated with the key RET ligand/co-receptor complex, GDNF/GFRa1, show improved progenitor function at primary transplantation and improved long-term HSC function at secondary transplantation. Finally, we demonstrate that RET drives a multi-faceted intracellular signalling pathway, including key signalling intermediates AKT, ERK1/2, NFkB and p53, responsible for a wide range of cellular and genetic responses which improve cell growth and survival under culture conditions

Distribution, Function, and Evolution of a Gene Essential for Trichothecene Toxin Biosynthesis in Trichoderma

[EN] Trichothecenes are terpenoid toxins produced by species in 10 fungal genera, including species of Trichoderma. The trichothecene biosynthetic gene (tri) cluster typically includes the tri5 gene, which encodes a terpene synthase that catalyzes formation of trichodiene, the parent compound of all trichothecenes. The two Trichoderma species, Trichoderma arundinaceum and T. brevicompactum, that have been examined are unique in that tri5 is located outside the tri cluster in a genomic region that does not include other known tri genes. In the current study, analysis of 35 species representing a wide range of the phylogenetic diversity of Trichoderma revealed that 22 species had tri5, but only 13 species had both tri5 and the tri cluster. tri5 was not located in the cluster in any species. Using complementation analysis of a T. arundinaceum tri5 deletion mutant, we demonstrated that some tri5 homologs from species that lack a tri cluster are functional, but others are not. Phylogenetic analyses suggest that Trichoderma tri5 was under positive selection following its divergence from homologs in other fungi but before Trichoderma species began diverging from one another. We propose two models to explain these diverse observations. One model proposes that the location of tri5 outside the tri cluster resulted from loss of tri5 from the cluster in an ancestral species followed by reacquisition via horizontal transfer. The other model proposes that in species that have a functional tri5 but lack the tri cluster, trichodiene production provides a competitive advantage.S

Primary care utilisation patterns among an urban immigrant population in the Spanish National Health System

<p>Abstract</p> <p>Background</p> <p>There is evidence suggesting that the use of health services is lower among immigrants after adjusting for age and sex. This study takes a step forward to compare primary care (PC) utilisation patterns between immigrants and the native population with regard to their morbidity burden.</p> <p>Methods</p> <p>This retrospective, observational study looked at 69,067 individuals representing the entire population assigned to three urban PC centres in the city of Zaragoza (Aragon, Spain). Poisson models were applied to determine the number of annual PC consultations per individual based on immigration status. All models were first adjusted for age and sex and then for age, sex and case mix (ACG System^®).</p> <p>Results</p> <p>The age and sex adjusted mean number of total annual consultations was lower among the immigrant population (children: IRR = 0.79, p < 0.05; adults: IRR = 0.73, p < 0.05). After adjusting for morbidity burden, this difference decreased among children (IRR = 0.94, p < 0.05) and disappeared among adults (IRR = 1.00). Further analysis considering the PC health service and type of visit revealed higher usage of routine diagnostic tests among immigrant children (IRR = 1.77, p < 0.05) and a higher usage of emergency services among the immigrant adult population (IRR = 1.2, p < 0.05) after adjusting for age, sex and case mix.</p> <p>Conclusions</p> <p>Although immigrants make lower use of PC services than the native population after adjusting the consultation rate for age and sex, these differences decrease significantly when considering their morbidity burden. These results reinforce the 'healthy migration effect' and discount the existence of differences in PC utilisation patterns between the immigrant and native populations in Spain.</p