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Search Results: 1 - 10 of 586920 matches for " Oscar; D'Acu?a "
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EVALUACIóN PRáCTICA DE ANATOMíA. RENDIMIENTO DE LOS ALUMNOS DE PRIMER A?O DE MEDICINA ANTE DISTINTAS FORMAS DE PREGUNTAR
Inzunza,Oscar; D'Acua,Eduardo; Bravo,Hermes;
International Journal of Morphology , 2003, DOI: 10.4067/S0717-95022003000200006
Abstract: to keep a high standard teaching anatomy, some innovations procedures have been introduded, to face facts such as diminution in the number of hours lectures, increase in the number of students, lack of cadaveric preparations and decrease in the number of available teachers. these innovation procedures include use of prosections, web pages with animated photographs, clinical images such as rx, tac, rnm. the practical test have incorporated questions related to these material which is available in the laboratory of anatomy and in the web site. this paper analize the performance of medical students in relation to the new form of asking questions related to the practical knowledge of anatomy. we compare the average grade of the students in six different types of questions: 1) cadaveric preparations shown in the laboratory, 2) animated photographs of the web, 3) rnm, 4) new cadaveric preparations 5) sectional anatomy and 6) rx. the analisis of the results shows that the students recognize easily the anatomical structures shown in the bidimensional figures (computer, rx, rnm). tridimensional preparation have more difficulty in the recognition of the anatomical structures. the difference in the average grades compare with the previous ones is statisticaly significant. the use of computer images to teach anatomy is an important help to the students. nevertheless the tridimentional understanding is not resolve by this teaching procedure. the study in the cadaveric preparations has its own value that can not be avoid
EVALUACIóN PRáCTICA DE ANATOMíA. RENDIMIENTO DE LOS ALUMNOS DE PRIMER A O DE MEDICINA ANTE DISTINTAS FORMAS DE PREGUNTAR PRACTICAL EVALUATION IN ANATOMY. PERFORMANCE OF FIRST YEAR MEDICAL STUDENTS IN RELATION TO DIFFERENT WAYS OF ASKING QUESTIONS
Oscar Inzunza,Eduardo D'Acua,Hermes Bravo
International Journal of Morphology , 2003,
Abstract: Los anatomistas hemos debido hacer innovaciones para mantener una ense anza de alto nivel, enfrentando factores como la disminución del horario lectivo, aumento del número de alumnos, falta de material cadavérico y de docentes. Los cambios incluyen el uso de disecciones preparadas con anticipación, desarrollo de una página Web con fotos animadas y el uso de imágenes clínicas (RX, TAC, RNM). Las pruebas prácticas del curso han incluido preguntas en este material, disponible en los pabellones de disección y en el sistema computacional. En este trabajo analizamos el rendimiento de los alumnos ante nuevas formas de evaluar el conocimiento práctico de Anatomía. Se compararon los puntajes obtenidos por los estudiantes en seis tipos de preguntas de reconocimiento en: 1.- Preparaciones cadavéricas que han visto con anterioridad. 2.- Fotos animadas de la página Web del curso. 3.- Imágenes de resonancia nuclear. 4.- Preparaciones anatómicas nuevas. 5.-Secciones anatómicas. 6.- Radiografías. El análisis estadístico de los resultados demostró que los alumnos reconocen con facilidad estructuras anatómicas en planos bidimensionales como la pantalla del computador o RX, presentando una complejidad mayor la identificación de elementos en las preparaciones cadavéricas o secciones de segmentos corporales; diferencias que son estadísticamente significativas. La utilización de imágenes anatómicas computacionales representan un apoyo importante a las actividades prácticas. Sin embargo, subsiste el problema de la concepción tridimensional de la estructura anatómica, que no alcanza a ser resuelta por el uso de las imágenes; resaltando el valor de las disecciones anatómicas en este tipo de cursos To keep a high standard teaching Anatomy, some innovations procedures have been introduded, to face facts such as diminution in the number of hours lectures, increase in the number of students, lack of cadaveric preparations and decrease in the number of available teachers. These innovation procedures include use of prosections, web pages with animated photographs, clinical images such as RX, TAC, RNM. The practical test have incorporated questions related to these material which is available in the laboratory of Anatomy and in the web site. This paper analize the performance of medical students in relation to the new form of asking questions related to the practical knowledge of Anatomy. We compare the average grade of the students in six different types of questions: 1) Cadaveric preparations shown in the laboratory, 2) Animated photographs of the web, 3) RNM, 4) New cadaveric prepa
Algunos aspectos de la variabilidad de los oogonios en poblaciones actuales del género Chara (Charophyceae). Aplicación paleontológica
Pedrola, J.,Acua, J. D.
Estudios Geologicos , 1986,
Abstract: A critical revision of some useful taxonomic criteria in paleontology of Charophytes is carried Out. The results are based in four modern populations ((Chara aculeolata, Chara aff.baltica, Chara delicatula and Chara globularis) and they permit to make some serious objections to these critera. The results are related with three principal aspects: the meaning of the absolute magnitudes of me girogonite, the behaviour of his joint variation and the morphological variability during the calcification process. In general, and for each one of the four populations, an absence of influence of the position of the girogonite over their measurements is observed. This doesn't happens when the verticil is considered as source of variation. These biometrical differences which are equivalent to some of those that has been used to distinguish fossil species, are not due to a process of progressive or heteregenous calcification in the secuence of verticils of me plant. Several arguments against the indiscriminate use of cocients between absolute magnitudes (e.g. the polarity index) as detectors of systematic interest are showed. In the same way, some remarks to the use of the morphology of the spiral calcificated cells, the prominence of the basal pore and some aspects of the apex shape, as taxonomic criteria are made. All this are variable within the same plant when there are differents in the calcification degree of the girogonites. Se hace una revisión crítica de-algunos criterios taxonómicos de uso habitual en paleontología de carofitas. Sus resultados, basados en cuatro poblaciones actuales (Chara aculeolata, Chara aff.baltica, Chara delicatula y Chara globularis), permiten hacer algunas serias objeciones a estos criterios. Dichos resultados se relacionan con tres aspectos principales: el significado de las magnitudes absolutas del girogonito, el comportamiento de su variación conjunta y la variabilidad morfológica durante el proceso de calcificación. De modo general y para cada una de las cuatro poblaciones. se observa una falla de influencia de la posición del girogonito en el filoide sobre sus dimensiones, cosa que no ocurre cuando se considera el verticilo como fuente de variación. Estas diferencias biométricas que son equivalentes a algunas de las que han sido utilizadas para diferenciar especies fósiles, no son debidas a un proceso de calcificación progresivo o heterogéneo en la secuencia de verticilos de la planta. Se exponen diferentes argumentos en contra del uso indiscriminado de cocientes entre magnitudes absolutas (p. e. el índice de isopolaridad) como d
Observaciones sobre algunos criterios tafonómicos usados en la interpretación de asociaciones malacológicas fósiles.
Puig, J.,Acua, J. D.
Estudios Geologicos , 1984,
Abstract: In the present paper a revision of some taphonomic criteria commonly used in the interpretation of fossil mollusca assemblages is realized . The field work on living and death assemblages of mollusca in a shallow muddy bottom has been carried out in the coast near Denia (Alicante, Spain). Although the supposed lineal relation between specific abundance and probability of autochthony could explain the structure of part of the considered assemblages, in other a clear disagreement due to a massive incursion of youth elements in observed . By other hand, the possibility of horizontal transport not detectable by these means (anonymous alochtonic fluxes) imposes another limitation to the pretended regularity, With regard to the mechanical breakdown and bioerosion of the shells phenomena, some generally admited biostratinomic criteria are confirmed: although both processes begin when the animal is still alive, they become more important after death, in the exposure phase before burial. The pretended relationship between probability of autochthony and state of preservation hasn't been possible to accept in the death assemblages. Se realiza una revisión de algunos criterios tafonómicos usados en la interpretación de asociaciones malacológicas fósiles. El estudio se lleva a cabo con la ayuda de los resultados proporcionados por el examen de las asociaciones vivas y muertas de gasterópodos y bivalvos de un fondo lutítico superficial próximo a la localidad alicantina de Denia. Aunque una pretendida relación directa entre abundancia específica y probabilidad de autoctonía podría explicar la estructura de una parte de las asociaciones encontradas, la incursión masiva de elementos juveniles ha constituido, en otras ocasiones, una clara discrepancia. Por otra parle, la probabilidad de flujos aléctonos anónimos para el método utilizado Limita aún más la supuesta regularidad. Respecto al significado de los fenómenos de pérdida de integridad y bioerosión de las conchas, se confirman algunos presupuestos generalmente admitidos en Bioestratinomía: ambos procesos comenzarían en vida del molusco, pero su desarrollo principal se daría durante la etapa de exposición tras la muerte. No ha podido aceptarse la existencia de una relación entre probabilidad de autoctonía de las especies y estado de conservaci6n de sus ejemplares en las asociaciones muertas
Validez y confiabilidad de la versión chilena del Alcohol Use Disorders Identification Test (AUDIT)
Alvarado,María Elena; Garmendia,María Luisa; Acua,Gonzalo; Santis,Rodrigo; Arteaga,Oscar;
Revista médica de Chile , 2009, DOI: 10.4067/S0034-98872009001100008
Abstract: background: audit is a self-reported questionnaire used to detect problem drinkers. it must be translated into spanish and validated in order to be used in chile. aim: to assess the validity of a chilean version of the audit questionnaire. material and methods: the english version of the questionnaire was translated into spanish and adapted to the chilean cultural environment. using the delphi method, an expert group examined the text and then decided on which would be the definitive version. this test was translated to english again and was approved by one of the original authors. it was then applied to 93 subjects aged 37 ± 12 years (60% males) consulting at a primary health care center these subjects also answered the composite international diagnostic interview (cidi), version 2.1 that was used as the gold standard for the diagnosis of hazardous drinking and alcohol dependence. cronbach alpha and test-retest validity were analyzed. sensitivity and specificity were determined using receiver operating (roc) curves. results: the internal consistency of audit was 0.93, its test re-tests reliability was 0.97 (95% confidence intervals 0.96-0.98). using a cutoff point of 6 for hazardous consumption, its sensitivity and specificity were 83% and 88%, respectively. the figures for dependence and harmful consumption, using a cutoff point of 9, were 87% and 85%, respectively. conclusions: audit is a valid questionnaire to detect problem drinkers.
Variación estacional en el consumo de roedores por la Lechuza de Campanario (Tyto alba) en un área suburbana de Chillán, centro-sur de Chile
González Acua,Daniel; Ausset Salgado,Marcelo; Skewes Ramm,Oscar; Figueroa Rojas,Ricardo A.;
El hornero , 2004,
Abstract: during two years (november 1999-december 2001) we studied the seasonal variation of the diet of the barn owl (tyto alba) in an suburban area of chillán, chile. on the basis of 259 pellets we identified 624 prey items. five native and introduced rodent species, one bird order, and two insect orders composed the diet. with the exception of the 1999 spring, rodents were the most consumed prey during all seasons (63-100% of all individual preys). among rodents, oligoryzomys longicaudatus was the most dominant prey by number (18-56%). the diet diversity tended to be lower during winter. geometric mean weight of rodent prey was seasonally variable, being lowest when oligoryzomys longicaudatus was less consumed. oligoryzomys longicaudatus and rattus rattus made major biomass contribution. a sharp seasonal variation was observed in the barn owl diet, being rodents significantly most consumed during fall-winter. seasonal consumption of birds also showed a significant variation, which was caused by its higher representation during spring 1999. oligoryzomys longicaudatus showed the highest fluctuations, being significantly consumed during winter. seasonal variation of the barn owl's diet in chillán was in close agreement with the temporal cycles of abundance of the rodent preys in southern chile. as compared to other rodent species, the highest consumption of oligoryzomys longicaudatus could be accounted by its differential vulnerability, probably caused by their scansorial habits, its tridimensional use of the habitat, and their widest displacements.
Biodegradación de petróleo y sus derivados por la comunidad bacteriana en un suelo de la Patagonia Argentina
Acua,Adrián; Pucci,Graciela; Morales,María José; Pucci,Oscar;
Revista de la Sociedad Venezolana de Microbiología , 2010,
Abstract: the purpose of this study was to characterize a soil sample obtained from an active bioremediation system and determine the capacity of the bacterial community for biodegrading petroleum and its distilled products, and identify the main microorganisms involved in the process. for this object a soil sample was taken with the lanfarming technique and its physical chemical and microbiological characteristics were characterized, as well as the type of hydrocarbons it contained by soxhlet extraction and silica gel column chromatography. from this sample we also extracted the bacterial community and determined its potential for degrading petroleum, its different fractions and the commercial distilled products obtained from it. we used indirect measurement methods for determining bacterial growth by counting the microorganisms and measuring optical densities. through these methods we isolated 42 strains and identified them by fame. the principal results indicated that the soil bacterial community has the capacity for degrading the hydrocarbons in it, mainly the aliphatic fraction as well as the distilled products such as gasoil, kerosene and lubricant oil, while the aromatic and polar fractions and the naphtha distilled product are non degradable. this community is mainly constituted by rhodococcus erythropolis, achromobacter xylosoxidans and brevundimonas diminuta, showing the greatest diversity when the hydrocarbons used as carbon source belong to the aliphatic group. the physical, chemical and microbiological characteristics of the soil indicated that it is possible that an efficient bioremediation of the hydrocarbons present occurs.
Disponibilidad de médicos en Chile al a?o 2004
Román A,Oscar; Acua F,Miguel; Se?oret S,Miriam;
Revista médica de Chile , 2006, DOI: 10.4067/S0034-98872006000800017
Abstract: background: the number of physicians available in a given country, their efficiency, quality and specialization is of utmost epidemiological importance. aim: to evaluate the availability of physicians in chile. material and methods: the information about the number of physicians in chile up to the year 2004, was obtained from the ministry of health, national universities and the register of immigrant physicians since 1950. results: the total number of physicians licensed to practice was 25,542, of whom 2,700 are immigrants. the physician/inhabitant ratio increased from 1/921 in 1998 to 1/612 in 2004. the greater impact in the increment of available physicians was given by the immigration of professionals and by the increase in the number of physicians graduated from national universities, mainly from the new private universities. forty two percent of physicians work at public services and 61% of these are certified specialists. the regional distribution of general practitioners and basic specialists is adequate. along the country, the mean physician/beneficiary ratio is 8.45/10,000, the specialist/beneficiary ratio is 4.9/10,000 and the general practitioner/beneficiary ratio is 2.3/10,000. conclusions: the national information of available physicians, especially in the private sector, should be improved. immigration of physicians should be regulated, maintaining validation examinations and a national medical test to assess medical proficiency should be instituted (rev méd chile 2006; 134: 1057-64).
Disponibilidad de médicos en Chile al a o 2004 Availability of physicians in Chile at the year 2004
Oscar Román A,Miguel Acua F,Miriam Se?oret S
Revista médica de Chile , 2006,
Abstract: Background: The number of physicians available in a given country, their efficiency, quality and specialization is of utmost epidemiological importance. Aim: To evaluate the availability of physicians in Chile. Material and methods: The information about the number of physicians in Chile up to the year 2004, was obtained from the Ministry of Health, national universities and the register of immigrant physicians since 1950. Results: The total number of physicians licensed to practice was 25,542, of whom 2,700 are immigrants. The physician/inhabitant ratio increased from 1/921 in 1998 to 1/612 in 2004. The greater impact in the increment of available physicians was given by the immigration of professionals and by the increase in the number of physicians graduated from national universities, mainly from the new private universities. Forty two percent of physicians work at public services and 61% of these are certified specialists. The regional distribution of general practitioners and basic specialists is adequate. Along the country, the mean physician/beneficiary ratio is 8.45/10,000, the specialist/beneficiary ratio is 4.9/10,000 and the general practitioner/beneficiary ratio is 2.3/10,000. Conclusions: The national information of available physicians, especially in the private sector, should be improved. Immigration of physicians should be regulated, maintaining validation examinations and a National Medical Test to assess medical proficiency should be instituted (Rev Méd Chile 2006; 134: 1057-64).
Fast Far Field Computation of Single and Dual Reflector Antennas
Marcos Arias-Acua,Antonio García-Pino,Oscar Rubi?os-López
Journal of Engineering , 2013, DOI: 10.1155/2013/140254
Abstract: The physical optics (PO) method has been widely used for the analysis of the electromagnetic behavior of single and dual reflector antennas. An extensive work has been done by the authors of this paper in order to increase the speed for obtaining far field patterns from single and dual geometries and also in order to increase the accuracy of the method. This paper reviews these contributions and improves the existing published work with the physical interpretation of the radiation from a single patch and the computer implications when using acceleration techniques such as OpenMP. 1. Introduction In engineering electromagnetic reflector antennas are commonly used for long-range radio communications, in applications such as satellite communications, radiolinks, and space exploration. In these applications it is necessary to accurately estimate the radiation pattern of the antenna to fulfill requirements such as gain, sidelobe levels, and cross-polar radiation. The electromagnetic scattering by metallic surfaces has been extensively treated in the literature with special emphasis on the reflector antenna application case. Usually, the radiated integral of the current on the metallic surface is numerically solved with the aid of some mathematical and physical approximations. The earliest method was based on series representation [1] in order to develop the radiated field. This mathematical approximation was then adapted to the case of an offset paraboloid using Jacobi polynomial series method [2]. The second type of mathematical approximation, based on numerical integration, was presented in [3], where it is demonstrated that the convergence depends on the choice of the integration grid coordinate system. In [4] popular numerical integration methods applied to the reflector antenna problem are compared. It was shown that the most accurate one to develop the surface integral consisted of using Gauss-Zernike polynomial integration for the radial coordinate and the trapezoidal rule for the angular coordinate along the circumference. Other very popular physical approximations are based on geometrical optics with aperture integration (GO + AI) and physical optics (PO). These techniques are compared in [5] for offset parabolic antenna. An alternative consists of combining GO with the geometrical theory of diffraction (GTD) to represent the reflector rim. In [6] it is demonstrated that the PO solution agrees well with the GO + GTD for the copolar component. In [7] the integration across the main reflector of a Cassegrain antenna is transferred to the aperture of
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