oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 2 )

2018 ( 24 )

2017 ( 37 )

2016 ( 56 )

Custom range...

Search Results: 1 - 10 of 18638 matches for " Brizuela Alberto "
All listed articles are free for downloading (OA Articles)
Page 1 /18638
Display every page Item
Interacting holographic tachyon model of dark energy
Alberto Rozas-Fernández,David Brizuela,Norman Cruz
Physics , 2010, DOI: 10.1142/S0218271810016580
Abstract: We propose a holographic tachyon model of dark energy with interaction between the components of the dark sector. The correspondence between the tachyon field and the holographic dark energy densities allows the reconstruction of the potential and the dynamics of the tachyon scalar field in a flat Friedmann-Robertson-Walker universe. We show that this model can describe the observed accelerated expansion of our universe with a parameter space given by the most recent observational results.
Is tetrahydrobiopterin a therapeutic option in diabetic hypertensive patients?
Alberto Francisco Rubio-Guerra, Hilda Vargas-Robles, Luz Maria Ramos-Brizuela, et al
Integrated Blood Pressure Control , 2010, DOI: http://dx.doi.org/10.2147/IBPC.S7479
Abstract: tetrahydrobiopterin a therapeutic option in diabetic hypertensive patients? Review (3902) Total Article Views Authors: Alberto Francisco Rubio-Guerra, Hilda Vargas-Robles, Luz Maria Ramos-Brizuela, et al Published Date September 2010 Volume 2010:3 Pages 125 - 132 DOI: http://dx.doi.org/10.2147/IBPC.S7479 Alberto Francisco Rubio-Guerra1, Hilda Vargas-Robles2, Luz Maria Ramos-Brizuela1, Bruno Alfonso Escalante-Acosta2 1Metabolic Clinic, Hospital General de Ticomán SS DF, Mexico; 2Department of Molecular Biomedicine, Centro de Investigacion y de Estudios Avanzados del IPN, Mexico Abstract: Nitric oxide (NO) is an important regulator of vascular tone, and is also an antithrombotic, anti-inflammatory, antiproliferative, and antiatherogenic factor. Endothelial function is altered in patients with coronary artery disease, stroke, and peripheral artery disease, and endothelial dysfunction correlates with the risk factor profile for a patient. Hypertension and type 2 diabetes are risk factors for vascular disease, and are both pathologies characterized by loss of NO activity. Indeed, endothelial dysfunction is usually present in diabetic and/or hypertensive patients. Tetrahydrobiopterin is an essential cofactor for the NO synthase enzyme, and insufficiency of this cofactor leads to uncoupling of the enzyme, release of superoxide, endothelial dysfunction, progression of hypertension, and finally, proatherogenic effects. Tetrahydrobiopterin is also an important mediator of NO synthase regulation in type 2 diabetes and hypertension, and may be a rational therapeutic target to restore endothelial function and prevent vascular disease in these patients. The aim of this paper is to review the rationale for therapeutic strategies directed to biopterins as a target for vascular disease in type 2 diabetic hypertensive patients.
Enfermedad cerebrovascular: epidemiología, diagnóstico y tratamiento. Hospital Vargas de Caracas, Venezuela 2006- 2007
Franco Carolina , Sánchez Cecilia , Fuenmayor Lianella, Brizuela Alberto , Chirinos Aléxis .
Acta Cientifica Estudiantil , 2009,
Abstract: Introducción: Las enfermedades cerebrovasculares suponen una de las primeras causas de discapacidad y morbilidad a nivel mundial; en los países occidentales constituye la tercera causa de muerte. En Venezuela, representan la quinta causa de mortalidad y se espera que las cifras sigan aumentando.Objetivo General: Describir la epidemiología, diagnóstico y tratamiento de la enfermedad cerebrovascular en pacientes internados en el Hospital Vargas de Caracas, durante el período 2006 – 2007.Material y Métodos: Estudio descriptivo, transversal, retrospectivo y observacional. El universo corresponde a los pacientes atendidos en el Hospital Vargas de Caracas durante el período 2006 - 2007. La muestra está representada por los pacientes con diagnóstico de Enfermedad cerebrovascular. Se revisaron 216 historias clínicas. Las variables fueron tabuladas en sistema computarizado Excel. El análisis de datos se realizó mediante medidas de tendencia central y porcentajes. La representación de los datos se realizó por medio de gráficos y tablas. Resultados: Se revisaron 216 historias clínicas; 92 cumplieron con los criterios de inclusión. 52,17% de los pacientes son del sexo femenino; la edad promedio es 65 a os; el 85% no mueren a causa de la enfermedad. 89,48% de los pacientes presentaron accidente cerebrovascular; de éstos el 71% son de tipo isquémico localizados en el territorio de la arteria cerebral media derecha. 54,35% de los pacientes padecen de hipertensión arterial no controlada. Conclusiones: La enfermedad cerebrovascular más frecuente es el accidente cerebrovascular de tipo isquémico; fuertemente asociado al antecedente de hipertensión arterial; por lo que se recomienda hacer mayor énfasis en su control.
Is tetrahydrobiopterin a therapeutic option in diabetic hypertensive patients?
Alberto Francisco Rubio-Guerra,Hilda Vargas-Robles,Luz Maria Ramos-Brizuela,et al
Integrated Blood Pressure Control , 2010,
Abstract: Alberto Francisco Rubio-Guerra1, Hilda Vargas-Robles2, Luz Maria Ramos-Brizuela1, Bruno Alfonso Escalante-Acosta21Metabolic Clinic, Hospital General de Ticomán SS DF, Mexico; 2Department of Molecular Biomedicine, Centro de Investigacion y de Estudios Avanzados del IPN, MexicoAbstract: Nitric oxide (NO) is an important regulator of vascular tone, and is also an antithrombotic, anti-inflammatory, antiproliferative, and antiatherogenic factor. Endothelial function is altered in patients with coronary artery disease, stroke, and peripheral artery disease, and endothelial dysfunction correlates with the risk factor profile for a patient. Hypertension and type 2 diabetes are risk factors for vascular disease, and are both pathologies characterized by loss of NO activity. Indeed, endothelial dysfunction is usually present in diabetic and/or hypertensive patients. Tetrahydrobiopterin is an essential cofactor for the NO synthase enzyme, and insufficiency of this cofactor leads to uncoupling of the enzyme, release of superoxide, endothelial dysfunction, progression of hypertension, and finally, proatherogenic effects. Tetrahydrobiopterin is also an important mediator of NO synthase regulation in type 2 diabetes and hypertension, and may be a rational therapeutic target to restore endothelial function and prevent vascular disease in these patients. The aim of this paper is to review the rationale for therapeutic strategies directed to biopterins as a target for vascular disease in type 2 diabetic hypertensive patients.Keywords: tetrahydrobiopterin, endothelial dysfunction, diabetes, hypertension, oxidative stress, nitric oxide, eNOS synthase uncoupling
EFFECTS OF THREE FEEDBACK CONDITIONS ON AEROBIC SWIM SPEEDS
Pedro Pérez Soriano,Salvador Llana Belloch,Gabriel Brizuela Costa,Alberto Encarnación Martinez
Journal of Sports Science and Medicine , 2009,
Abstract: The purpose of this study was twofold: (a) to develop an underwater chronometer capable to provide feedback while the athlete is swimming, as well as being a control tool for the coach, and (b) to analyse its feedback effect on swim pace control compared with feedback provided by the coach and with no feedback, in 25 m and 50 m swimming pools. 30 male swimmers of national level volunteer to participate. Each swimmer swam 3 x 200 m at aerobic speed (AS) and 3 x 200 m just under the anaerobic threshold speed (AnS), each swam repetition with a different feedback condition: chronometer, coach and without feedback. Results (a) validate the chronometer system developed and (b) show that swimmers pace control is affected by the type of feedback provided, the swim speed elected and the size of the swimming pool
Statistical moments for classical and quantum dynamics: formalism and generalized uncertainty relations
David Brizuela
Physics , 2014, DOI: 10.1103/PhysRevD.90.085027
Abstract: The classical and quantum evolution of a generic probability distribution is analyzed. To that end, a formalism based on the decomposition of the distribution in terms of its statistical moments is used, which makes explicit the differences between the classical and quantum dynamics. In particular, there are two different sources of quantum effects. Distributional effects, which are also present in the classical evolution of an extended distribution, are due to the fact that all moments can not be vanishing because of the Heisenberg uncertainty principle. In addition, the non-commutativity of the basic quantum operators add some terms to the quantum equations of motion that explicitly depend on the Planck constant and are not present in the classical setting. These are thus purely-quantum effects. Some particular Hamiltonians are analyzed that have very special properties regarding the evolution they generate in the classical and quantum sector. In addition, a large class of inequalities obeyed by high-order statistical moments, and in particular uncertainty relations that bound the information that is possible to obtain from a quantum system, are derived.
Classical versus quantum evolution for a universe with a positive cosmological constant
David Brizuela
Physics , 2015, DOI: 10.1103/PhysRevD.91.085003
Abstract: A homogeneous and isotropic cosmological model with a positive cosmological constant is considered. The matter sector is given by a massless scalar field, which can be used as an internal time to deparametrize the theory. The idea is to study and compare the evolutions of a quantum and a classical probability distribution by performing a decomposition of both distributions in their corresponding moments. For the numerical analysis an initial peaked Gaussian state in the volume will be chosen. Furthermore, in order to check the robustness of certain results, as initial state both a slightly deformed Gaussian, as well as another completely different state, will also be studied. Differences and similarities between classical and quantum moments are pointed out. In particular, for a subset of moments classical and quantum evolutions are quite similar, but certain variables show remarkable differences.
Classical and quantum behavior of the harmonic and the quartic oscillators
David Brizuela
Physics , 2014, DOI: 10.1103/PhysRevD.90.125018
Abstract: In a previous paper a formalism to analyze the dynamical evolution of classical and quantum probability distributions in terms of their moments was presented. Here the application of this formalism to the system of a particle moving on a potential is considered in order to derive physical implications about the classical limit of a quantum system. The complete set of harmonic potentials is considered, which includes the particle under a uniform force, as well as the harmonic and the inverse harmonic oscillators. In addition, as an example of anharmonic system, the pure quartic oscillator is analyzed. Classical and quantum moments corresponding to stationary states of these systems are analytically obtained without solving any differential equation. Finally, dynamical states are also considered in order to study the differences between their classical and quantum evolution.
Quantum back-reaction in a universe with positive cosmological constant
David Brizuela
Physics , 2011, DOI: 10.1088/1742-6596/360/1/012026
Abstract: Semiclassical techniques have proven to be a very powerful method to extract physical effects from different quantum theories. Therefore, it is expected that in the near future they will play a very prominent role in the context of quantum gravity. In this work we develop systematic tools to derive semiclassical approximations for any quantum theory with one degree of freedom. In our approach, the wave function is decomposed in terms of an infinite set of moments, which encode the complete quantum information of the system. Semiclassical regimes can then be properly described by truncation of this infinite system. The use of efficient computer algebra tools allows us to compute the equations of motion up to a very high order. In this way, we can study very precisely the quantum back reaction of the system as well as the convergence of the method with the considered order. Finally, these tools are applied to the particular case of a homogeneous universe filled with a massless scalar field and positive cosmological constant, which provide interesting physical results.
Características Clínicas del sangramiento digestivo alto
Pozo González,Alberto; Corimayta Gutierrez,Yasmany; Jaime Carballo,Yelena; Barbán Fernández,Leonor; Brizuela Pérez,Susana M;
Revista Archivo M??dico de Camag??ey , 2010,
Abstract: background: it is considered digestive bleeding is high if its origin is proximal to the treitz′ ligament, this health problem is admission motive in 100 for each 100 000 inhabitants and mortality for its cause oscillates between a 5 and 10%, its incidence increases with the age and its proportion of men: women are of 2:1, besides being very related with anti-inflammatory use. objective: to describe clinical characteristics of patients with high digestive bleeding in the health area of the educational polyclinic previsora from january 2007 to january 2008. method: a descriptive study of cross-sectional cohort was performed. the study universe was constituted by seventy-four patients, the sample coincided with the study universe, data collecting was carried out through the individual clinical histories and a questionnaire was elaborated in personal interview, which became in data primary registration. data processing was carried out with descriptive statistic methods, frequency distribution and proportion distribution test according to the system pss for windows, results were presented in charts. results: a prevalence of high digestive bleeding was appreciated in the age group from 60 to 79 years, being the masculine sex the most affected one. the most frequent cause was peptic ulcer and the great majority belonged to the group ii-c, according to forrest classification. conclusions: peptic ulcer was the most frequent pathological antecedent in high digestive bleeding. the most frequent form of presentation was the melena. alcoholism was the predisposing factor with more frequency was presented. most of the studied patients did not consume non steroid anti-inflammatory. the iic forrest stage was observed with more frequency.
Page 1 /18638
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.