Search results for " física"
showing 10 items of 920 documents
Optimización y caracterización de la calidad de imagen en tomografía por emisión de positrones
2012
Las distintas modalidades de la Imagen Médica tienen un mismo objetivo, obtener una imagen que represente un parámetro físico de interés del interior del paciente. Y para todas ellas la calidad final de la imagen médica viene determinada por cómo de bien se represente la verdadera distribución espacial que el parámetro físico tiene en el interior paciente. Para poder obtener una imagen médica de calidad es necesario conocer en profundidad la física implicada en el proceso de medida. El conocimiento de los fundamentos físicos en los que se basa cada una de las técnicas de Imagen Médica nos permite conocer los factores que van a contribuir a la degradación de las magnitudes que definen la cal…
Adsorption dynamics of molecular nitrogen at an Fe(111) surface.
2017
We present an extensive theoretical study of N adsorption mechanisms on an Fe(111) surface. We combine the static analysis of a six-dimensional potential energy surface (6D-PES), based on ab initio density functional theory (DFT) calculations for the system, with quasi-classical trajectory (QCT) calculations to simulate the adsorption dynamics. There are four molecular adsorption states, usually called γ, δ, α, and ε, arising from our DFT calculations. We find that N adsorption in the γ-state is non-activated, while the threshold energy is associated with the entrance channel for the other three adsorption states. Our QCT calculations confirm that there are activated and nonactivated paths …
Modulation of Irisin and Physical Activity on Executive Functions in Obesity and Morbid obesity
2016
Whether the executive profile is different between obesity (OB) and morbid obesity (MO) remains unclear. Recent evidence suggests that physical activity (PA) can act as a cognitive enhancer. Irisin is a recently discovered hormone associated with some of the positive effects of PA. The objective of the study was to investigate the executive profile in OB and MO, and to explore the role of PA and irisin. 114 participants were included (21 OB, 44 MO and 49 healthy controls-HC) in the study and assessed with the Wisconsin Card Sorting Test, Stroop Color and Word Test, and Iowa Gambling Task. All participants were female, aged between 18 and 60 years. Results showed a similar dysfunctional prof…
Fast noniterative orbital localization for large molecules
2006
We use Cholesky decomposition of the density matrix in atomic orbital basis to define a new set of occupied molecular orbital coefficients. Analysis of the resulting orbitals ("Cholesky molecular orbitals") demonstrates their localized character inherited from the sparsity of the density matrix. Comparison with the results of traditional iterative localization schemes shows minor differences with respect to a number of suitable measures of locality, particularly the scaling with system size of orbital pair domains used in local correlation methods. The Cholesky procedure for generating orthonormal localized orbitals is noniterative and may be made linear scaling. Although our present implem…
Synthesis and characterization of a Cu(II) complex of 2-benzylmercapto-5- methyl-1,3,4-thiadiazole (C10H10N2S 2)
2008
A Cu(II) complex of 2-benzylmercapto-5-methyl-1,3,4-thiadiazole was synthesized and characterized. The crystal structure of the copper complex and the free ligand were determined by single-crystal X-ray diffraction at room temperature: {[Cu(C10H10N2S2) 2(Cl)2], P1 triclinic, a = 8.1450(2) Å, b = 8.1690(2) Å, c = 10.8180(3) Å, α = 97.4040(12)°, β = 101.6270(11)°, γ = 116.1431(14)°; C10H10N2S2 ligand, Pbca orthorhombic, a = 8.7938(7) Å, b = 9.6491(7) Å, c = 25.3552(18) Å}. The metal complex framework consists of discrete units that provide crystalline stability through a network of van der Waals contacts. The Cu(II) is coordinated by two chloride ions and two 2-benzylmercapto-5-methyl-1,3,4- …
La historia de vida de una educadora de profesores de Educación Física: su desarrollo personal y profesional
2003
Carmina Pascual Baños: Carmina.Pascual@uv.es Este artículo se centra en mi propia Historia de vida como educadora de profesores de Educación Física desde una perspectiva postmoderna. Através del análisis de documentos personales y académicos como mi autobiografía escrita, los artículos publicados, mi diario, la tesis doctoral, el proyecto docente y los programas de las asignaturas que imparto, trato de explicar mi desarrollo personal y profesional, las circunstancias que han contribuido al mismo, así como el contexto en el que se ha producido. The focus of this paper is my own Life History as teacher educator of Physical Education teachers within a postmodernist orientation. Throughout the …
Selected dissociation‐ and correlation‐consistent configuration interaction by a perturbative criterion
1990
We propose a perturbative criterion to select the most important dissociation‐ or correlation‐consistent type of contributions to perform generalized valence bond‐configuration interaction (GVB‐CI) calculations, dissociation‐consistent configuration interaction (DCCI) or correlation‐consistent configuration interaction (CCCI) approach, respectively. The procedure presented is computationally less demanding than the CCCI proposed by Goddard and co‐workers. To ensure the distance consistency of the MOs used, the nonvalence virtual orbitals are obtained by a projection technique. The results obtained for a few test calculations show the ability of the suggested approach to get close results to…
The relationship between out-of-school sport participation and positive youth development
2012
Carreres-Ponsoda F, Escarti A, Cortell-Tormo JM, Fuster-Lloret V, Andreu-Cabrera E. The relationship between out-of-school sport participation and positive youth development. J. Hum. Sport Exerc. Vol. 7, No. 3, pp. 671-683, 2012. Despite growing evidence that participation in out-of-school activities and especially physical activity and sport programs facilitates positive development, little developmental research has been conducted on out-of-school sports programs compared with no participation in these activities or participation in other activities. Our study examined the participation of youth in out of school sport activities compared with participation in other out-of-school activitie…
Effects of a Teaching Personal and Social Responsibility Model Intervention in Competitive Youth Sport
2021
The aim of this study was to implement the teaching personal and social responsibility (TPSR) model in a competitive context analyzing the differences between the intervention and the control group on personal and social responsibility, prosocial behaviors, and self-efficacy in youth soccer players. Participants were 34 youth soccer players between the ages of 14 and 16 years old (15.18 ± 0.72) divided into two different soccer teams of 17 members, corresponding to the control and intervention groups. The implementation of the TPSR model took place during 9 months, including initial and ongoing coach training (3 months), program implementation (three sessions per week lasting 90 min during …
Finalidades de la enseñanza de las ciencias en la Secundaria obligatoria. ¿Alfabetización científica o preparación propedéutica?
2001
Resumen basado en el de la revista El propósito de este trabajo es encontrar las ideas, propósitos y objetivos de los profesores de ciencias dentro del marco de las reformas educativas. Se trata de revelar en que medida el pensamiento educativo da prioridad a la enseñanza de los estudiantes en los conceptos científicos, leyes y teorías necesarias en cursos superiores (capacitación propedéutica) y como este pensamiento presta menos atención a la llamada alfabetización científica lo cual se suponía iba a ser el principal objetivo de la enseñanza de ciencias de acuerdo con los diseños del currículum . Al lograr esto, se lleva a cabo un diseño experimental multiple y convergente con un múmero d…