635 research outputs found
On the critical point structure of eigenfunctions belonging to the first nonzero eigenvalue of a genus two closed hyperbolic surface
We develop a method based on spectral graph theory to approximate the eigenvalues and eigenfunctions of the Laplace-Beltrami operator of a compact riemannian manifold -- The method is applied to a closed hyperbolic surface of genus two -- The results obtained agree with the ones obtained by other authors by different methods, and they serve as experimental evidence supporting the conjectured fact that the generic eigenfunctions belonging to the first nonzero eigenvalue of a closed hyperbolic surface of arbitrary genus are Morse functions having the least possible total number of critical points among all Morse functions admitted by such manifold
Estudio del desarrollo de mentores como guías de docentes principiantes de la República Dominicana
A Study in Cuba of the Biology, Ecology and Agroecological Management of \u3cem\u3eHeteropsylla Cubana\u3c/em\u3e Crawford in \u3cem\u3eLeucaena Leucocephala\u3c/em\u3e (Lam.) de Wit
As a consequence of the increase in Leucaena leucocephala areas to counter the shortage of feed in Cuban cattle production, there is a risk of the development of Heteropsylla cubana Crawford (Hemiptera: Psyllidae) as a pest in silvopastoral systems with this legume. This psyllid is known to be the main phytophagous pest (Valenciaga, 2003), which produces damage in 95% of the apical region of branches. Since information on the identification and biology of a pest species is a necessary prerequisite for its management, a taxonomic, biological and ecological study was conducted to define Heteropsylla behaviour in Cuban conditions and elaborate the theoretical basis to propose management alternatives
Comparison of delignified coconuts waste and cactus for fuel-ethanol production by the simultaneous and semi-simultaneous saccharification and fermentation strategies
It is of the highest importance to study different alternatives/strategies as simultaneous (SSF) and semi-simultaneous (SSSF) saccharification and fermentation process, as well as the prospects of the utilization of lignocellulosic residues as raw materials for fuel-ethanol production. In the first part of this work, different raw materials (cactus (CAC), green coconut shell (GCS), mature coconut fibre (MCF) and mature coconut shell (MCS)) were pretreated by sequential alkaline hydrogen peroxide (Alk-H2O2)–sodium hydroxide (NaOH) process. The characterization of the obtained solids by FTIR, SEM, X-ray and crystallinity indexes confirmed the higher susceptibility of these pretreated materials to enzymatic action. These results were further confirmed by the corresponding glucose conversion yields – 68.44%, 70.20%, 76.21% and 74.50% for CAC, GCS, MCF and MCS, respectively. Subsequently, the comparison between SSF and SSSF using Saccharomyces cerevisiae, Pichia stipitis, Zymomonas mobilis and pretreated MCF (selected in the enzymatic hydrolysis step) was done, being shown that a short presaccharification step at 50 °C for 8 h in the SSSF had a positive effect on the overall ethanol yield, with an increase from 79.27–84.64% to 85.04–89.15%. In all the cases, the SSSF strategy allowed the obtention of higher ethanol concentrations than SSF.The authors gratefully acknowledge the Brazilian research funding agencies CNPq and CAPES for financial support
Prevalencia de los defectos del habla en pacientes con maloclusiones dentales
El objetivo del presente trabajo es establecer la prevalencia de defectos del habla en pacientes diagnosticados con maloclusiones dentales en los tres planos del espacio, asistentes a las clínicas de Ortodoncia de la Universidad Cooperativa de Colombia, sede Bogotá, en el año 2012. Se realizó un estudio descriptivo de corte transversal en 68 pacientes diagnosticados con maloclusión dental, mediante un examen clínico de la cavidad oral, para evaluar las características oclusales encontradas en los planos sagital, transversal y vertical aplicando el método de registro epidemiológico de Bjork. Así mismo se les realizó una grabación de la narración espontánea con un equipo TASCAM DR-100MKII®, diagnosticando defectos del habla según el punto de articulación usando el programa PHON® para la transcripción fonética. Los resultados mostraron que los defectos del habla con mayor prevalencia fue la linguoalveolar (98,5%) seguida de la bilabial (7,4%) y linguodental (4,4%). La totalidad de los pacientes diagnosticados con defectos del habla presentaron algún tipo de maloclusión en el plano sagital, clase I (69,1%); en el plano vertical fue la mordida abierta anterior (25%), y en el plano transversal la mordida cruzada (19,1%). Los defectos del habla de las sílabas /cr/, /gr/ y /pr/ se relacionaron con la maloclusión clase III. Los sonidos más alterados fueron los linguoalveolares (/ s / ɾ̼ / r̼ /) y las sílabas trabadas con /r/, lo que sugiere las mal oclusiones como factor de riesgo para la presencia de dislalias
Un índice de sustentabilidad para la evaluación integral de los sistemas de gestión del agua y el saneamiento
En este trabajo se presenta un índice para la evaluación de la sustentabilidad de los sistemas de gestión del agua y el saneamiento. El índice, denominado ISAS (Índice de Sustentabilidad del Agua y el Saneamiento) se basa en un marco conceptual que considera que la sustentabilidad se debería ver como una combinación de aspectos territoriales, temporales y personales. Para la construcción del ISAS se seleccionaron un conjunto de indicadores de sustentabilidad que fueron definidos en función del marco conceptual adoptado. El ISAS se utilizó para evaluar la sustentabilidad del sistema de gestión del agua y el saneamiento de la ciudad de Salta, Argentina. Los indicadores fueron calculados con información de revisiones bibliográficas, cuestionarios, visitas, talleres, datos estadísticos, y análisis de muestras de agua y aguas residuales. El método fue lo suficientemente sensible como para detectar variaciones entre diferentes aspectos del sistema estudiado. Fue también relativamente independiente de la cantidad y la calidad de la información disponible. En el caso de Salta, el valor obtenido para el ISAS fue de 51 puntos en una escala de 0 a 100 cuyo umbral de aceptabilidad se estableció en 50 puntos. El cálculo del ISAS permitió identificar una serie de aspectos del sistema que requieren mejoras y optimización. Este índice puede ser una herramienta útil para evaluar y mejorar la sustentabilidad de los sistemas de gestión del agua y el saneamiento en la región.A comprehensive sustainability index for the assessment of water and sanitation management systems (WSMS) is presented. The index was based on a conceptual framework that perceives sustainability as a combination of territorial, temporal, and personal aspects. A set of sustainability indicators was selected in agreement with this framework, and the “Water and Sanitation Sustainability Index” (WASSI) was built. The WASSI was then used to assess the sustainability of the WSMS of the city of Salta, Argentina. Indicators were calculated with information gathered by several means including literature reviews, questionnaires, visits, sampling, and participatory workshops. The index was sensitive to detect variations between different aspects of the local WSMS. It was also relatively independent of the quantity and quality of the information available. In the case of Salta, the value obtained for the index was 51 points in a scale going from 0 to 100 in which the acceptability threshold was set at 50 points. The WASSI could be a useful tool to assess and improve the sustainability of regional water and sanitation management systems.Fil: Seghezzo, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Iribarnegaray, Martín Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Liberal, V. I.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Copa, F. R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Guerra Munizaga, M. S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: León, H. E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Ruíz, C. Y.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta; Argentin
On the development of the final optical multiplexer board prototype for the TileCal experiment
This paper describes the architecture of the final optical multiplexer board for the TileCal experiment. The results of the first VME 6U prototype have led to the definition of the final block diagram and functionality of this prototype. Functional description of constituent blocks and the state of the work currently undergoing at the Department of Electronic Engineering, in collaboration with IFIC-Valencia, is presented. As no board is yet produced, no experimental results are presented but, nevertheless, design issues that have been taking into account as component placement and signal integrity issues will be detailed
Registro para México de Lissonota Fascipennis Townes (hymenoptera: ichneumonidae) como parasitoide del gusano rojo del maguey
Wind power field reconstruction from a reduced set of representative measuring points
In this paper we deal with a problem of representative measuring points selection for long-term wind power analysis. It has direct applications such as wind farm prospective location or long-term power generation prediction in wind-based energy facilities. The problem’s objective is to select the best set of N measuring points (i.e. N representative points), in such a way that a wind power error reconstruction measure is minimized, considering a monthly average wind power field. In order to solve this problem, we use a novel meta-heuristic algorithm, the Coral Reefs Optimization with Substrate Layer, which is an evolutionary-type method able to combine different search procedures within a single population. The CRO-SL is hybridized with the Analogue Method as wind power reconstruction method, to identify the most representative points for the wind field. The proposed approach has been tested in the reconstruction of monthly average wind power fields in Europe, from reanalysis data (ERAInterim reanalysis). The method exhibits strong performance as evidenced from the experiments carried out. The solutions obtained show that the more significant measuring points are mainly located over the Atlantic ocean, which is consistent with the wind speed climatology of the Northern hemisphere midlatitudes. We have also analyzed the set of least representative points to reconstruct the wind power field (less informative points for whole reconstruction of the field), obtaining points mainly located at the North of Scandinavia (which may be associated with the circumpolar circulation), and some points in the Eastern Mediterranean, which seem to be related to the Etesian winds. Reconstructions at seasonal scales show similar results, which provides confidence on the robustness of the proposed method. The proposed methodology can be further applied to alternative energy-related problems, such as the selection of critical energy infra-structures or the selection of critical points for climate change studies, among others
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