A K-Theoretic Proof of Boutet de Monvel's Index Theorem for Boundary Value Problems

We study the C*-closure A of the algebra of all operators of order and class zero in Boutet de Monvel's calculus on a compact connected manifold X with non-empty boundary. We find short exact sequences in K-theory 0->K_i(C(X))->K_i(A/K)->K_{1-i}(C_0(T*X'))->0, i= 0,1, which split, where K denotes the compact ideal and T*X' the cotangent bundle of the interior of X. Using only simple K-theoretic arguments and the Atiyah-Singer Index Theorem, we show that the Fredholm index of an elliptic element in A is given as the composition of the topological index with mapping K_1(A/K)->K_0(C_0(T*X')) defined above. This relation was first established by Boutet de Monvel by different methods.Comment: Title slightly changed. Accepted for publication in Journal fuer die reine und angewandte Mathemati

Families index for Boutet de Monvel operators

We define the analytical and the topological indices for continuous families of operators in the C*-closure of the Boutet de Monvel algebra. Using techniques of C*-algebra, K-theory, and the Atiyah–Singer theorem for families of elliptic operators on a closed manifold, we prove that these two indices coincide

A Variable Kinematic One-Dimensional Model for the Hygro-Mechanical Analysis of Composite Materials

Composite materials are widely used in many engineering fields. Their mechanical properties allow very stiff structures to be obtained with a mass reduction with respect to metallic materials. These materials are built using a polymeric matrix reinforced with high strength fibres, e.g. carbon fibres. The use of a polymeric matrix makes composite materials subject to aging effects and in particular their properties and performances may be reduced because of the moisture absorption. An accurate prediction of the deformations and of the internal stress field due to the hygro-mechanical effects is mandatory in the design of a composite structure exposed to a moisture concentration. Classical structural models, beams and plates, cannot provide a complete three-dimensional stress field because their kinematic assumption, e.g. rigid crosssection for the beam of constant thickness for the plates. These limitations make the classical models inaccurate when complex three-dimensional stress fields have to be evaluated as in the case of the hygro-mechanical problem, that is, a full three-dimensional model must be used. The present paper proposes to use a refined one-dimensional model with variable kinematic, developed in the frameworks of the Carrera Unified Formulation (CUF), for the hygromechanical analysis of composite structures. Refined one-dimensional models are able to overcome the limitations of the classical beam models thanks to a refined kinematic fields, used over the cross-section, able to provide a full three-dimensional solution. In this work a model based on Lagrange functions is used. The hygro-mechanical model has been derived in the CUF frameworks, that is, the moisture concentration can be considered as a variable of the problem. The moisture concentration has been evaluated solving analytically the Fick law that is able to provide the moisture distribution after a certain time of exposure. The moisture concentration has been used as boundary condition in the hygro-mechanical problem in order to evaluate the displacement and stress fields. The model has been assessed and the results have been compare with those from classical threedimensional FE models. Displacements field, stress field and the volume variation have been used to compare the accuracy of the solution. The results show that the refined one-dimensional models are able to provide an accurate solution with a lower computational cost with respect to the full three-dimensional FE models

Spin constrained orbital angular momentum control in high-harmonic generation

The interplay between spin and orbital angular momentum in the up-conversion process allows us to control the macroscopic wave front of high harmonics by manipulating the microscopic polarizations of the driving field. We demonstrate control of orbital angular momentum in high harmonic generation from both solid and gas phase targets using the selection rules of spin angular momentum. The gas phase harmonics extend the control of angular momentum to extreme-ultraviolet wavelength. We also propose a bi-color scheme to produce spectrally separated extreme-ultraviolet radiation carrying orbital angular momentum

Identification of suitable internal control genes for expression studies in Coffea arabica under different experimental conditions

<p>Abstract</p> <p>Background</p> <p>Quantitative data from gene expression experiments are often normalized by transcription levels of reference or housekeeping genes. An inherent assumption for their use is that the expression of these genes is highly uniform in living organisms during various phases of development, in different cell types and under diverse environmental conditions. To date, the validation of reference genes in plants has received very little attention and suitable reference genes have not been defined for a great number of crop species including <it>Coffea arabica</it>. The aim of the research reported herein was to compare the relative expression of a set of potential reference genes across different types of tissue/organ samples of coffee. We also validated the expression profiles of the selected reference genes at various stages of development and under a specific biotic stress.</p> <p>Results</p> <p>The expression levels of five frequently used housekeeping genes (reference genes), namely <it>alcohol dehydrogenase </it>(<it>adh</it>), <it>14-3-3</it>, <it>polyubiquitin </it>(<it>poly</it>), <it>β-actin </it>(<it>actin</it>) and <it>glyceraldehyde-3-phosphate dehydrogenase </it>(<it>gapdh</it>) was assessed by quantitative real-time RT-PCR over a set of five tissue/organ samples (root, stem, leaf, flower, and fruits) of <it>Coffea arabica </it>plants. In addition to these commonly used internal controls, three other genes encoding a cysteine proteinase (<it>cys</it>), a caffeine synthase (<it>ccs</it>) and the 60S ribosomal protein L7 (<it>rpl7</it>) were also tested. Their stability and suitability as reference genes were validated by geNorm, NormFinder and BestKeeper programs. The obtained results revealed significantly variable expression levels of all reference genes analyzed, with the exception of <it>gapdh</it>, which showed no significant changes in expression among the investigated experimental conditions.</p> <p>Conclusion</p> <p>Our data suggests that the expression of housekeeping genes is not completely stable in coffee. Based on our results, <it>gapdh</it>, followed by <it>14-3-3 </it>and <it>rpl7 </it>were found to be homogeneously expressed and are therefore adequate for normalization purposes, showing equivalent transcript levels in different tissue/organ samples. <it>Gapdh </it>is therefore the recommended reference gene for measuring gene expression in <it>Coffea arabica</it>. Its use will enable more accurate and reliable normalization of tissue/organ-specific gene expression studies in this important cherry crop plant.</p

Articulación entre la Escuela Secundaria Río Negrina y la Universidad Nacional del Comahue. Compartiendo espacios de Conocimiento.

Desde hace unos años el CRUB se vincula con las escuelas de Educación Media de Bariloche a través de diferentes proyectos y actividades. En este proyecto, se trabajara la articulación desde diferentes enfoques, el educativo y su inclusión social, los participantes docentes, investigadores y alumnos de las diferentes carreras del CRUB, junto a los docentes de la ESRN, proponen talleres para trabajar con los alumnos de 4to y 5to año de las ESRN. En las temáticas de los talleres se abarcaran problemáticas ambientales, la relación de los microorganismos delsuelo con los cultivos, actividades recreativas, arte y cultura, entre otros temas. Alguno de los objetivos del proyecto son:• Desarrollar en los estudiantes de Nivel Secundario la comprensión conceptual y metodológica básica requerida para tener buen desempeño académico, tanto en lo que resta de la escolaridad media como en el ingreso al nivel de estudios siguiente.• Generar instancias en las que los estudiantes del ciclo superior del Nivel Secundario puedan tener una primera aproximación al trabajo de investigación. Por ejemplo colaborar en proyectos de investigación del CRUB y de otras instituciones de San Carlos de Bariloche como CNEA, INTA, INVAP, etc.• Generar actividades recreativas solidarias en territorio con el fin de intercambiar     conocimientos y contribuir desde una mirada de universidad social, abierta, solidaria y extensionista con la comunidad que nos rodea, con la participación de los alumnos y docentes de Educación Secundaria y Universitaria.Integrantes: Alumna ALLENDE, Guadalupe; Alumno ARRIX, Gustavo; Prof. BRATASZCZUK, Elena; Alumna CRISMAN, Lorena Belén; Doctora DE LA ROSA, Iris Nadia; Alumno FIORONI, Facundo; Alumna GALLARDO FLORES, Rocio; Directora GANUZA, Carola; Alumna GOMEZ JOUSSE, Micaela; Profesora GUEVARA LINCHY, Magdalena; Prof. MARTINEZ, Ricardo; Doctora MESTRE, María Cecilia; Directora MILIAUSKAS, Monica; Alumna MOLINA, Juliana L.Y.; Alumno MONTEIRO, Jairo; Alumno OCHANDIO, Agustín; Alumno OJEDA, Fernando; Prof. PACHECO, Carla; Alumno PRIETO, Ricardo; Alumna REYES, Luna; Alumno ROBINSON, Patricio; Alumna RODRIGUEZ, Guadalupe; Lic. SANCHEZ, Maria Ines; Alumno SCHULZ, Franco; Alumno SOTO MANCILLA, Matías A.; Alumna WOICIK, Maria Camil