938 resultados para 3-D geological model
Resumo:
Valorar el modelo de Feuerstein (FIE) en su ámbito de adquisición de habilidades de pensamiento, en alumnos de escolaridad normal, desde la perspectiva de la acción pedagógica y desde una óptica teórica y experimental. Grupo experimental: 85 alumnos de sexto nivel de EGB, de un centro privado, procedentes de familias de status socioeconómico medio-alto, del curso académico 1986-87 y 1987-88. Grupo control: alumnos de las mismas características que los anteriores de otro centro privado. Describe la teoría y materiales de Feuerstein. Discusión de las bases teóricas del FIE. Valora el programa y lo contrasta con otros modelos. Experimenta el modelo para evaluar las aptitudes mentales que mejoran en los alumnos después de la aplicación del programa. Plantea un diseño con grupo control pretest posttest. V.I.: Participación o no en el programa. V.D.: Mejora en las aptitudes. Controla variables intervinientes. Aplica el programa al grupo experimental y una batería de tests pretest y posttest a los dos grupos para medir las aptitudes. Analiza los datos y complementa los resultados con un un estudio sobre las actitudes del profesorado y los alumnos hacia el FIE. Instrumentos del programa: organización de puntos, orientación espacial I y II, comparaciones, clasificaciones, percepción analítica y relaciones familiares. Batería de tests: test de comprensión verbal, test de fluidez verbal, test de razonamiento abstracto, test de aptitud numérica, test de comprensión espacial, test de memoria y test de rapidez perceptiva. ANCOVA, ANOVA, t de Student, índices de fiabilidad y validez y representaciones gráficas. El FIE mejora fluidez verbal y rapidez perceptiva. Potencia la eficacia en tareas donde se requiere una estrategia sencilla. Es suficiente para desarrollar el razonamiento abstracto, la memoria o el razonamiento numérico. Puede contrarestar déficits en la comprensión verbal pero no mejora el razonamiento espacial. Los alumnos tienen una opinión positiva hacia el FIE y los profesores creen que los alumnos han mejorado en sus hábitos de estudio, autoconcepto y capacidad de comunicación verbal, pero no puede generalizarse una mejora en el rendimiento académico. El modelo cognitivo-natural de acción pedagógica en el ámbito de la adquisición de habilidades de pensamiento queda corroborado. Es uno de los programas más completos para aprender a pensar. Plantea la prospectiva de investigar los efectos del FIE en la esfera emotiva, mejorar los instrumentos de medida y estudiar el grado de generabilidad de las conclusiones.
Resumo:
Analizar el acceso al léxico escrito, como variable que se correlaciona con la comprensión lectora, en el sordo. Para aplicación en ESO. Evaluación y tratamiento de forma psicopedagógica del problema para determinar las bases de un modelo de incidencia en el léxico. Explorar determinados aspectos relacionados con la comprensión del léxico escrito. Analizar la incidencia de diversas estrategias pedagógicas en la solución del problema. 22 alumnos sordos profundos prelocutivos escolarizados en ciclo superior de EGB de centros públicos del Vallès con un mínimo de tres años de integración escolar. Otro grupo de oyentes de la misma edad y otro de oyentes con la misma edad lectora. Selección de la muestra a través de contacto con escuelas y logopedas de la zona. Elaboración de instrumentos para la intervención psicopedagógica y posterior evaluación. Cuestionarios ad hoc, test WISC, test de aprendizajes instrumentales (Canals, 1989). Tablas, esquemas, dibujos, análisis estadístico. Resultados estructurados en base a las diferentes pruebas y aglutinados en la conclusión. Tras aplicar el modelo psicopedagógico experimental el rendimiento lector ha mejorado en diversos aspectos: metacognición lexical, reglas de transformación de palabras, discriminación de pseudopalabras, determinación de títulos, etc. Junto a esto se deduce una inestabilidad en el aprendizaje en los alumnos sordos por pérdida de conocimientos previos que se consideraban asumidos y que pueden ser olvidados por la dificultad en la memorización a largo plazo de contenidos saturados de factores verbales. Planteamiento de un modelo de intervención que debe ser ajustado de forma puntual a los sujetos.
Resumo:
The first 3-D open-framework TiGaPO complex, constructed from (TiO6)-O-III, (TiO6)-O-IV, GaO4, and PO4 polyhedra, contains pyridinium cations in a 1-D pore network and can be oxidized in air at 543 K with retention of the original framework structure.
Resumo:
A new 3-D zinc phosphate, [C5N2H14][Zn-2(PO3(OH))(3)], has been synthesised under solvothermal conditions in the presence of 1-methylpiperazine. The structure, determined by single-crystal X-ray diffraction at 293 K (RMM = 520.9, orthorhombic, space group P2(1)2(1)2(1); a = 10.0517(2) &ANGS;, b = 10.4293(2) &ANGS; and c = 14.9050(5) &ANGS;; V = 1562.52 &ANGS;(3); Z = 4; R(F) = 2.60%, wR(F) = 2.93%), consists of vertex linked ZnO4 and PO3(OH) tetrahedra assembled into (4.8) net sheets which in turn are linked through further PO3(OH) units to generate a 3-D framework. 1-Methylpiperazinium cations reside within the 3-D channel system, held in place by a strong network of hydrogen bonds. The (4.8) net sheets occur in a number of zeolite structures e.g. ABW and GIS and related zinc phosphate phases. © 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.
Resumo:
This correspondence introduces a new orthogonal forward regression (OFR) model identification algorithm using D-optimality for model structure selection and is based on an M-estimators of parameter estimates. M-estimator is a classical robust parameter estimation technique to tackle bad data conditions such as outliers. Computationally, The M-estimator can be derived using an iterative reweighted least squares (IRLS) algorithm. D-optimality is a model structure robustness criterion in experimental design to tackle ill-conditioning in model Structure. The orthogonal forward regression (OFR), often based on the modified Gram-Schmidt procedure, is an efficient method incorporating structure selection and parameter estimation simultaneously. The basic idea of the proposed approach is to incorporate an IRLS inner loop into the modified Gram-Schmidt procedure. In this manner, the OFR algorithm for parsimonious model structure determination is extended to bad data conditions with improved performance via the derivation of parameter M-estimators with inherent robustness to outliers. Numerical examples are included to demonstrate the effectiveness of the proposed algorithm.
Resumo:
A new 3-D zinc phosphate, [C5N2H14][Zn-2(PO3(OH))(3)], has been synthesised under solvothermal conditions in the presence of 1-methylpiperazine. The structure, determined by single-crystal X-ray diffraction at 293 K (RMM = 520.9, orthorhombic, space group P2(1)2(1)2(1); a = 10.0517(2) &ANGS;, b = 10.4293(2) &ANGS; and c = 14.9050(5) &ANGS;; V = 1562.52 &ANGS;(3); Z = 4; R(F) = 2.60%, wR(F) = 2.93%), consists of vertex linked ZnO4 and PO3(OH) tetrahedra assembled into (4.8) net sheets which in turn are linked through further PO3(OH) units to generate a 3-D framework. 1-Methylpiperazinium cations reside within the 3-D channel system, held in place by a strong network of hydrogen bonds. The (4.8) net sheets occur in a number of zeolite structures e.g. ABW and GIS and related zinc phosphate phases. © 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.
Resumo:
Incorporation of a bicyclic cytosine analogue, 3-beta-D-(2'-deoxyribofuranosyl)7,8- dihydropyrido[ 2,3-d] pyrimidine, into synthetic DNA duplexes results in a greatly enhanced thermal stability ( 3 - 4 degrees C per modification) compared to the corresponding unmodified duplex.
Resumo:
Objective. This study was designed to determine the precision and accuracy of angular measurements using three-dimensional computed tomography (3D-CT) volume rendering by computer systems. Study design. The study population consisted of 28 dried skulls that were scanned with a 64-row multislice CT, and 3D-CT images were generated. Angular measurements, (n = 6) based upon conventional craniometric anatomical landmarks (n = 9), were identified independently in 3D-CT images by 2 radiologists, twice each, and were then performed by 3D-CT imaging. Subsequently, physical measurements were made by a third examiner using a Beyond Crysta-C9168 series 900 device. Results. The results demonstrated no statistically significant difference between interexaminer and intraexaminer analysis. The mean difference between the physical and 3-D-based angular measurements was -1.18% and -0.89%, respectively, for both examiners, demonstrating high accuracy. Conclusion. Maxillofacial analysis of angular measurements using 3D-CT volume rendering by 64-row multislice CT is established and can be used for orthodontic and dentofacial orthopedic applications.
Resumo:
Vector field formulation based on the Poisson theorem allows an automatic determination of rock physical properties (magnetization to density ratio-MDR-and the magnetization inclination-MI) from combined processing of gravity and magnetic geophysical data. The basic assumptions (i.e., Poisson conditions) are: that gravity and magnetic fields share common sources, and that these sources have a uniform magnetization direction and MDR. In addition, the previously existing formulation was restricted to profile data, and assumed sufficiently elongated (2-D) sources. For sources that violate Poisson conditions or have a 3-D geometry, the apparent values of MDR and MI that are generated in this way have an unclear relationship to the actual properties in the subsurface. We present Fortran programs that estimate MDR and MI values for 3-D sources through processing of gridded gravity and magnetic data. Tests with simple geophysical models indicate that magnetization polarity can be successfully recovered by MDR-MI processing, even in cases where juxtaposed bodies cannot be clearly distinguished on the basis of anomaly data. These results may be useful in crustal studies, especially in mapping magnetization polarity from marine-based gravity and magnetic data. (c) 2007 Elsevier Ltd. All rights reserved.
Resumo:
In medical processes where ionizing radiation is used, dose planning and dose delivery are the key elements to patient safety and treatment success, particularly, when the delivered dose in a single session of treatment can be an order of magnitude higher than the regular doses of radiotherapy. Therefore, the radiation dose should be well defined and precisely delivered to the target while minimizing radiation exposure to surrounding normal tissues [1]. Several methods have been proposed to obtain three-dimensional (3-D) dose distribution [2, 3]. In this paper, we propose an alternative method, which can be easily implemented in any stereotactic radiosurgery center with a magnetic resonance imaging (MRI) facility. A phantom with or without scattering centers filled with Fricke gel solution is irradiated with Gamma Knife(A (R)) system at a chosen spot. The phantom can be a replica of a human organ such as head, breast or any other organ. It can even be constructed from a real 3-D MR image of an organ of a patient using a computer-aided construction and irradiated at a specific region corresponding to the tumor position determined by MRI. The spin-lattice relaxation time T (1) of different parts of the irradiated phantom is determined by localized spectroscopy. The T (1)-weighted phantom images are used to correlate the image pixels intensity to the absorbed dose and consequently a 3-D dose distribution with a high resolution is obtained.
Resumo:
To investigate the role of β-(1-3)-D-glucan on 99mTc labelled Escherichia coli translocation and cytokines secretion in rats submitted to small bowel ischemia/reperfusion injury. Methods: Five groups (n=10 each) of Wistar rats were subjected to control(C), sham(S), group IR subjected to 45 min of bowel ischemia/60 min of reperfusion(I/R), and group I/R+glucan subjected to 45 min of bowel ischemia/60 min of reperfusion(I/R) and injected with 2mg/Kg intramuscular. Translocation of labelled bacteria to mesenteric lymph nodes, liver, spleen, lung and serum was determined using radioactivity/count and colony forming units/g(CFU/g). Serum TNFα, IL-1β, IL-6, IL-10 were measured by ELISA. Results: CFU/g and radioactivity/count were higher in I/R than in I/R+glucan rats. In C, S and S+glucan groups, bacteria and radioactivity/count were rarely detected. The I/R+glucan rats had enhancement of IL-10 and suppressed production of serum TNFα, IL-1β and, IL-6, compared to I/R untreated animals. Conclusion: The β-(1-3)-D-glucan modulated the production of pro-inflammatory and anti-inflammatory cytokines during bowel ischemia/reperfusion, and attenuated translocation of labelled bacteria
Resumo:
To investigate the role of β-(1-3)-D-glucan on 99mTc labelled Escherichia coli translocation and cytokines secretion in rats submitted to small bowel ischemia/reperfusion injury. Methods: Five groups (n=10 each) of Wistar rats were subjected to control(C), sham(S), group IR subjected to 45 min of bowel ischemia/60 min of reperfusion(I/R), and group I/R+glucan subjected to 45 min of bowel ischemia/60 min of reperfusion(I/R) and injected with 2mg/Kg intramuscular. Translocation of labelled bacteria to mesenteric lymph nodes, liver, spleen, lung and serum was determined using radioactivity/count and colony forming units/g(CFU/g). Serum TNFα, IL-1β, IL-6, IL-10 were measured by ELISA. Results: CFU/g and radioactivity/count were higher in I/R than in I/R+glucan rats. In C, S and S+glucan groups, bacteria and radioactivity/count were rarely detected. The I/R+glucan rats had enhancement of IL-10 and suppressed production of serum TNFα, IL-1β and, IL-6, compared to I/R untreated animals. Conclusion: The β-(1-3)-D-glucan modulated the production of pro-inflammatory and anti-inflammatory cytokines during bowel ischemia/reperfusion, and attenuated translocation of labelled bacteria