5,751 research outputs found
Induction, minimization and collection for Δ n+1 (T)–formulas
For a theory T, we study relationships among IΔ n +1 (T), LΔ n+1 (T) and B * Δ n+1 (T). These theories are obtained restricting the schemes of induction, minimization and (a version of) collection to Δ n+1 (T) formulas. We obtain conditions on T (T is an extension of B * Δ n+1 (T) or Δ n+1 (T) is closed (in T) under bounded quantification) under which IΔ n+1 (T) and LΔ n+1 (T) are equivalent. These conditions depend on Th Πn +2 (T), the Πn+2 –consequences of T. The first condition is connected with descriptions of Th Πn +2 (T) as IΣ n plus a class of nondecreasing total Πn –functions, and the second one is related with the equivalence between Δ n+1 (T)–formulas and bounded formulas (of a language extending the language of Arithmetic). This last property is closely tied to a general version of a well known theorem of R. Parikh. Using what we call Πn –envelopes we give uniform descriptions of the previous classes of nondecreasing total Πn –functions. Πn –envelopes are a generalization of envelopes (see [10]) and are closely related to indicators (see [12]). Finally, we study the hierarchy of theories IΔ n+1 (IΣ m ), m≥n, and prove a hierarchy theorem.Ministerio de Educación y Cultura DGES PB96-134
An empirical formulation to describe the evolution of the high burnup structure
In the present work the behavior of fuel pellets for LWR power reactors in the high burnup range (average burnup higher than about 45 MWd/kgU) is analyzed. For extended irradiation periods, a considerable Pu concentration is reached in the pellet periphery (rim zone), that contributes to local burnup. Gradually, a new microstructure develops in that ring, characterized by small grains and large pores as compared with those of the original material. In this region Xe is absent from the solid lattice (although it continues to be dissolved in the rest of the pellet). The porous microstructure in the pellet edge causes local changes in the mechanical and thermal properties, thus affecting the overall fuel behaviour. It is generally accepted that the evolution of porosity in the high burnup structure (HBS) is determinant of the retention capacity of the fission gases rejected from the fuel matrix. This is the reason why, during the latest years a considerable effort has been devoted to characterizing the parameters that influence porosity. Although the mechanisms governing the microstructural transformation have not been completely elucidated yet, some empirical expressions can be given, and this is the intention of the present work, for representing the main physical parameters. Starting from several works published in the open literature, some mathematical expressions were developed to describe the behaviour and progress of porosity at local burnup values ranging from 60 to 2 300 MWd/kgU. The analysis includes the interactions of different orders between pores, the growth of the pore radius by capturing vacancies, the evolution of porosity, pore number density and overpressure within the closed pores, the inventory of fission gas dissolved in the matrix and retained in the pores. The model is mathematically expressed by a system of non-linear differential equations. In the present work, results of this calculation scheme are compared with experimental data available in the open literature and with simulations performed by other authors. The results of these separate tests are quite satisfactory so, the next step will be the incorporation of this model as a new subroutine of the DIONISIO code, to expand the application range of this general fuel behaviour simulation tool.Fil: Lemes, MartÃn. Comisión Nacional de EnergÃa Atómica; ArgentinaFil: Soba, Alejandro. Comisión Nacional de EnergÃa Atómica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Denis, Alicia Catalina. Comisión Nacional de EnergÃa Atómica; Argentin
Deep inelastic scattering off scalar mesons in the 1/N expansion from the D3D7-brane system
Deep inelastic scattering (DIS) of charged leptons off scalar mesons in the 1/N expansion is studied by using the gauge/gravity duality. We focus on the D3D7-brane system and investigate the corresponding structure functions by considering both the high energy limit and the 1/N expansion. These limits do not commute. From the D7-brane DBI action we derive a Lagrangian at sub-leading order in the D7-brane fluctuations and obtain a number of interactions some of which become relevant for two-hadron final-state DIS. By considering first the high energy limit followed by the large N one, our results fit lattice QCD data within 1.27% for the first three moments of F 2 for the lightest pseudoscalar meson.Fil: Jorrin, David Gustavo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto de FÃsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FÃsica La Plata; ArgentinaFil: Kovensky, Nicolas. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto de FÃsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FÃsica La Plata; ArgentinaFil: Schvellinger, MartÃn Alejandro. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto de FÃsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FÃsica La Plata; Argentin
The specificity of psychologist’s function in the field of mental disability
Se propone un análisis de la dimensión polÃtica de la función psi y de la función del psicólogo en el campo de la discapacidad mental. Desde el análisis de dispositivos institucionales y prácticas manicomiales existentes, se explicita que el modelo médico individual comanda el abordaje tradicional. Se plantea que la función del psicólogo podrÃa implicar una perspectiva desmanicomializadora, cuestionando la patologización, medicalización e institucionalización de la discapacidad. Desde esta lógica serÃa posible una lectura diferente respecto de las dificultades actuales en relación a la autonomÃa e integración. El aspecto ético-polÃtico de la praxis favorecerÃa movimientos autogestionados por los propios individuos en situación de discapacidad, transformación posible solo a partir de pensar la discapacidad desde el modelo social.The present work analyzes the politic dimension of the psy function, as well as psychologist’s function in the field of mental disability. From the analysis of the institutional devices and asylums practices, a prevalence of the individual model in the direction of traditional treatments can be stated. Psychologist’s function could be conceived from a des-institunalising perspective, in a way to question the pathologization, medicalization and institutionalization of disability. From this logic, a different understanding of current difficulties in autonomy and integration could be envisioned. Finally, the ethical-political aspect of praxis would favour self-managed movements in disability situations, a transformation that could only be possible from the social model framework.Fil: Contino, Alejandro MartÃn. Universidad Nacional de Rosario; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
Desarrollo rural y nuevos espacios rurales : el caso de Villa Rio y su experiencia comunitaria
En el marco de un fenómeno vinculado a los cambios globales el espacio rural de la Argentina se transforma presentando diferentes caracterÃsticas en relación a su configuración territorial y a los modos de producir particularmente en el ámbito doméstico. En este marco el Desarrollo Rural también se reconceptualiza y resinifica sus prácticas. El presente trabajo pretende estudiar la experiencia colectiva de Villa RÃo en la localidad de Anisacate acompañada por la Asociación Civil GETAL y un equipo técnico interinstitucional. En el recorrido realizado por pobladores y técnicos se buscan respuestas a demandas de mejora de la condiciones de producción y de reproducción de la vida cotidiana, en un contexto de transformación del territorio donde los nuevos usos de la tierra, el avance de la urbanización, los cambios en los modos de producir configuran nuevas intervenciones desde las polÃticas institucionales de Desarrollo Rural. Es un estudio exploratorio que reconstruye la experiencia a partir de la mirada de los pobladores y de los cuadernos de campo realizados por el autor en la intervención. A su vez se documentan y sistematizan los cambios contextuales de la Localidad de Anisacate y la zona y se propone su lectura del conjunto a la luz de conceptos construidos a partir de una indagación bibliográfica en torno a los cambios globales del capitalismo actual, a la Nueva Ruralidad, a los modos domésticos de producción y del Desarrollo Rural. La nueva realidad del territorio local plantea como desafÃo pensar abordajes en los que se tenga en cuenta la dimensión territorial, el conocimiento, los intereses y la participación protagónica de los diversos actores, el respeto al medio al medioambiente, el fortalecimiento de las producciones domésticas y el Desarrollo Rural pensado desde la AgroecologÃa que tiene aportes para hacer desde esta perspectiva
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