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Search Results: 1 - 10 of 193163 matches for " D. Bravo "
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La separación de poderes en la Primera Constitución Espa ola
Enrique Díaz Bravo
Nómadas , 2012,
Abstract: En el presente trabajo se realiza un análisis de la separación de poderes en la primera Constitución espa ola, la de Cádiz de 1812. Comenzando con un repaso de los sucesos revolucionarios producidos a raíz de la invasión francesa, y las consecuencias que se produjeron en el ámbito político, lo que influenciado por el movimiento liberal europeo, lo que da lugar a la construcción de nuevos conceptos que permiten llevar a cabo un nuevo ordenamiento constitucional, el que sin precedentes en cuanto su integración y sobre todo por el lugar donde se residencia la soberanía, está vez en la nación.
Aproximaciones jurídico-políticas sobre el prinicio de separación de poderes del Estado
Enrique Díaz Bravo
Nómadas , 2012,
Abstract: En presente artículo el autor analiza el surgimiento del Estado en su etapa capitalista y las condiciones que lo provocan, transitando desde el feudalismo y la concepción de la desigualdad natural de los individuos, hasta la construcción de la idea política de igualdad de los individuos, como presupuesto para establecer un nuevo sistema de relaciones de poder. El nuevo orden se articula por un centro que distribuye el poder en varias funciones delegadas, a fin de evitar la concentración del poder.
Comparing regression methods to predict species richness patterns
D. Nogués-Bravo
Web Ecology (WE) , 2009, DOI: 10.5194/we-9-58-2009
Abstract: Multivariable regression models have been used extensively as spatial modelling tools. However, other regression approaches are emerging as more efficient techniques. This paper attempts to present a synthesis of Generalised Regression Models (Generalized Linear Models, GLMs, Generalized Additive Models, GAMs), and a Geographically Weighted Regression, GWR, implemented in a GAM, explaining their statistical formulations and assessing improvements in predictive accuracy compared with linear regressions. The problems associated with these approaches are also discussed. A digital database developed with Geographic Information Systems (GIS), including environmental maps and bird species richness distribution in northern Spain, is used for comparison of the techniques. GWR using splines has shown the highest improvement in accounted deviance when compared with traditional linear regression approach, followed by GAM and GLM.
An Approach for Micropropagation of Blueberry (Vaccinium corymbosum L.) Plants Mediated by Temporary Immersion Bioreactors (TIBs)  [PDF]
Ariel D. Arencibia, Carolina Vergara, Karla Quiroz, Basilio Carrasco, Carmen Bravo, Rolando Garcia-Gonzales
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.45126

A new procedure for blueberry (Vaccinium corymbosum L.) micropropagation in programmed Temporary Immersion Bioreactors (TIBs based on two separate bottles) was developed for the commercial genotypes Biloxi, Sharp Blue and Brillita. Plant cultures were developed in a controlled environment with 0.4 MPa CO2 enrichment, sucrose-reduced medium, and light intensity of 60 mM m-2·s-1. Principal component analysis showed that component 1 (C1) grouped 64.08% of the total variability, while the first two components accounted for 86.97%. Representation of the principal components demonstrated three clusters corresponding with the blueberry genotypes, and within each cluster plants micropropagated in agar-base medium grouped separately from those plants multiplied in TIBs. Both plant number and total internodes traits (related to the productive efficiency) were demonstrated superior in blueberries propagated in TIBs. Additionally, when transferred to greenhouse conditions, blueberries propagated in TIBs showed higher adaptability and growing rates than those cultured by the conventional approach, altogether evidencing the occurrence of a photomixotrophic stage in the vitroplantlets cultured in TIBs.

Spatial and Temporal Evolution of the Static Water Level of the Cuauhtemoc Aquifer during the Years 1973, 1991 and 2000: A Geographical Approach  [PDF]
Luis C. Alatorre, Rolando E. Díaz, Sonia Miramontes, Luis C. Bravo, Erick Sánchez
Journal of Geographic Information System (JGIS) , 2014, DOI: 10.4236/jgis.2014.65047
Abstract: In hydrogeology it is of great interest to examine the temporal and spatial evolution of aquifers. There are different ways of modeling an aquifer: physical models, models based on analog and mathematical techniques. Usually, mathematical techniques involve complex operations difficult to understand for some people, such as differential or partial equations. In contrast, our method requires only a basic knowledge of geometry and trigonometry. Moreover, it is only necessary to know the static level of the aquifer at three different dates. Of course, the results may be limited compared to those that use advanced mathematical methods; however, our method provides a first approximation to determine the behavior of the aquifer through time. Overall, our results allowed us to follow the evolution of the aquifer in detail of various areas of increased extraction and in which removal has been increasing, but also of areas with a considerable recharge during the study period.
Inzunza,Oscar; D'Acu?a,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
Romboencefalitis por Listeria monocytogenes: Caso clínico
Bravo M,Mauricio; Ferrer D,Sergio; Trujillo V,Sergio;
Revista médica de Chile , 1998, DOI: 10.4067/S0034-98871998000700011
Abstract: we report a previously healthy 44 years old female, that presented with mild clouding of consciousness, a left cerebellar syndrome, involvement of v, x and xii left cranial nerves and an alteration of epicritic sensitivity in the left half of the body. cerebrospinal fluid had inflammatory features. cerebrospinal fluid and blood cultures were positive for listeria monocytogenes. magnetic resonance imaging disclosed a rhomboencephalitis. antibiotics were started and the clinical condition of the patient improved progressively. after three months of follow up, the patient is notably recovered and there is a regression of hyperintense lesions of the brainstem in the magnetic resonance imaging. the diagnosis of listeria monocytogenes infection must be born in mind in the presence of a rhomboencephalitis.
Adaptation and monitoring of microorganisms in petroleum industry wastewater nitrification processes Adaptación y monitoreo de microorganismos en procesos de nitrificación en aguas residuales de la industria petrolera
Madero A.,Bravo G.,Carvajal F.,Díaz M.
Revista Colombiana de Biotecnología , 1998,
Abstract: Biological removal of ammonia nitrogen is carried out in two successive stages, nitrification and denitrification. This work studied the nitrification process on microorganisms isolated from different aquifer sources: a eutrophicate pond and residual waters from two treatment plants (petrochemical and domestic) La remoción biológica de nitrógeno amoniacal se lleva a cabo en dos etapas sucesivas, la nitrificación y la desnitrificación. La nitrificación se estudió en un grupo de microorganismos aislados a partir de diferentes fuentes acuíferas: una ciénaga eutrificada y aguas residuales procedentes de dos plantas de tratamiento; una de tipo petroquímico y otra de origen doméstico. Los microorganismos se evaluaron en condiciones oxigénicas a 305K en un sistema semicontinuo. Se comprobó la buena adaptación de los microorganismos en aguas residuales de origen petroquímico en procesos de remoción de nitrógeno amoniacal.
Oscar Inzunza,Eduardo D'Acu?a,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
Efecto del raleo en el crecimiento y algunas propiedades de la madera de Eucalyptus nitens en una plantación de 15 a os Effect of thinning on growth and some properties of wood of Eucalyptus nitens in a plantation of 15 years old
Sandro Díaz Bravo,Miguel Espinosa,Luis Valenzuela,Jorge Cancino
MADERAS : Ciencia y Tecnología , 2012,
Abstract: El raleo tiene implicancias económicas y técnicas tanto para producción forestal como para la actividad industrial. En el presente estudio se realizó la evaluación de un ensayo de intensidad de raleo en E. nitens, de 15 a os de edad, intervenido a los 7 y 9 a os, con densidades residuales de 300, 400, 500, 700 y un tratamiento testigo con 1070 arb ha-1. El objetivo es conocer el efecto del raleo en el diámetro y altura de los árboles, coeficiente de esbeltez, en los índices de competencia área potencialmente aprovechable (APA), área de proyección de copas (APC) y en las propiedades de la madera, densidad básica, módulo de elasticidad dinámico (MOEd) y las tensiones de crecimiento evaluadas con la deformación residual longitudinal de la fibra (DRL). Los resultados mostraron que el raleo afectó el diámetro, coeficiente de esbeltez, APA y APC, no así la altura. El raleo tampoco tuvo efecto en la densidad básica de la madera y en el DRL. Por otra parte el MOEd fue afectado por el raleo, pero sin mostrar claras tendencias respecto de su intensidad. El efecto de la orientación del fuste en el MOEd y el DRL, mostró valores significativamente mayores en la orientación Sur. Thinning has significant technical and economic implications for both forest managers and industrial end users. In the present study a 15 year old Eucalyptus nitens thinning experiment was evaluated. Thinnings operations were carried out at 7 and 9 years, with final stockings of 300, 400, 500, 700 and a control treatment of 1070 trees ha-1. The aim was to determine the effect of thinning on (i) stem diameter and tree height, stem slenderness ratio, (ii) competition indices: potentially usefull area (PUA), crown projection area (CPA) and (iii) wood properties: basic density, dynamic modulus of elasticity (Moed) and growth stresses evaluated using the residual deformation of the fiber length (DRL). The results showed that thinning affected tree diameter, slenderness index, PUA and CPA, but not total height. Thinning had no effect on basic density and DRL. On the other hand Moed was affected by thinning, but did not show a clear trend with thinning intensity. The effect of the stem orientation on DRL and Moed showed significantly higher values on the South side.
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