Amplificación sísmica: Una aproximación por Elementos Finitos

En las páginas que siguen se presenta el estudio de uno de los más típicos problemas de dinámica estructural, cual es la obtención de la respuesta de una estructura excitada por un movimiento de la base. Este es un caso muy frecuente en ingeniería sísmica, donde el objeto del estudio puede ser el edificio (sometido a un movimiento en la cimentación) o un estrato de terreno sobre fondo rígido. Al objeto de facilitar un soporte intuitivo a la exposicióri, ésta se organiza en base al segundo de los casos citados (estrate en base rígida). La aproximación escogida, elementos finitos, pone de relieve una vez más la potencia y generalidad del método en lo que respecta a la formulación del sistema de equilibrio. La discusión se centra en un aspecto concreto del método: la elección de funciones de forma.The goal of this paper is to present the analysis of one of the most typical problems in dynamics: the response of a structure excited by a rigid-base motion. This is an usual case in seismic engineering, where the structure can be a building or a soil stratum lying on a rigid bed. In both cases the model will be the same but, in order to give a physical support to exposure, the later will be treated. The choosed approach, by finite elements, points up the power and the generality of that method with respect to equilibrium formulation. Emphasis is done over the choosing of shape functions.Peer Reviewe

Constructing Agency: The Role of Language

Is agency a straightforward and universal feature of human experience? Or is the construction of agency (including attention to and memory for people involved in events) guided by patterns in culture? In this paper we focus on one aspect of cultural experience: patterns in language. We examined English and Japanese speakers’ descriptions of intentional and accidental events. English and Japanese speakers described intentional events similarly, using mostly agentive language (e.g., “She broke the vase”). However, when it came to accidental events English speakers used more agentive language than did Japanese speakers. We then tested whether these different patterns found in language may also manifest in cross-cultural differences in attention and memory. Results from a non-linguistic memory task showed that English and Japanese speakers remembered the agents of intentional events equally well. However, English speakers remembered the agents of accidents better than did Japanese speakers, as predicted from patterns in language. Further, directly manipulating agency in language during another laboratory task changed people’s eye-witness memory, confirming a possible causal role for language. Patterns in one’s linguistic environment may promote and support how people instantiate agency in context

The demand for sports and exercise: Results from an illustrative survey

Funding from the Department of Health policy research programme was used in this study.There is a paucity of empirical evidence on the extent to which price and perceived benefits affect the level of participation in sports and exercise. Using an illustrative sample of 60 adults at Brunel University, West London, we investigate the determinants of demand for sports and exercise. The data were collected through face-to-face interviews that covered indicators of sports and exercise behaviour; money/time price and perceived benefits of participation; and socio- economic/demographic details. Count, linear and probit regression models were fitted as appropriate. Seventy eight per cent of the sample participated in sports and exercise and spent an average of £27 per month and an average of 20 min travelling per occasion of sports and exercise. The demand for sport and exercise was negatively associated with time (travel or access time) and ‘variable’ price and positively correlated with ‘fixed’ price. Demand was price inelastic, except in the case of meeting the UK government’s recommended level of participation, which is time price elastic (elasticity = −2.2). The implications of data from a larger nationally representative sample as well as the role of economic incentives in influencing uptake of sports and exercise are discussed.This article is available through the Brunel Open Access Publishing Fund

Treatment outcome of children with severe acute malnutrition admitted to therapeutic feeding centers in Southern Region of Ethiopia

Background: Inadequate intake of carbohydrates, proteins, vitamins and minerals is one of the causes for malnutrition. It often affects young children and contributes to more than 60% of deaths in children in developing countries. One in four of malnourished children receiving traditional treatment die during or soon after treatment. The study aimed to assess the treatment outcome of children treated in therapeutic feeding centers (TFC) in southern Ethiopia.Methods: A retrospective review of reports submitted by the TFCs was done during 2003-2004. Data was collected from the monthly reports using standardized formats. The variables included age, treatment centers, type of malnutrition and treatment outcome which were analyzed using descriptive statistics.Results: Of 11,335 cases of malnutrition, 47% (5447) had severe wasting and 53% (6103) had edematous malnutrition. Of the total, 87% (11,191) were cured while 3.6% (468) had died. The average length of stay was 25 and 21 days with an average weight gain of 14 and 13.4 g/kg/d for children with severe wasting and edematous malnutrition, respectively. With increasing age, the death rate decrease  and cure rate increased (p < 0.05 for both).Discussion: Our results show that the new management approach  implemented in the TFC improved the treatment outcome of malnourished children compared to the minimum international standard set for  management of severe acute malnutrition which is cure rate of at least 75% and death rate less than 10%, average length of stay of less than30 days and average weight gain of 8g/kg/day

Percepción de la salud y actividades realizadas en el tiempo libre por adolescentes que viven en medios rurales

[Resumen] Este trabajo examina los efectos del estilo de vida en la percepción de la salud. La pobla- ción objeto de estudio está formada por 1109 escolares de 10 a 16 años que viven en el medio rural de dos comunidades españolas. En el estudio hemos utilizado como instru- mento de trabajo el cuestionario Self- Administered Physical Activity Checklist (SAPAC) adaptado a la población española. Recurrimos al análisis de tipo descriptivo, al análisis inferencial y la prueba de contraste Chi cuadrado (x2). Los resultados demostra- ron la existencia de diferencias en la percep- ción de la salud en función del sexo (p=.000), de la edad (p=.000) y del lugar de residencia (p=.015). De igual forma el consumo televisi- vo (p=.029), el tiempo dedicado al ordenador (p=.034), el tiempo dedicado a las tareas esco- lares (p=.034) y la realización de actividad física (p=.000) se relacionan con la percep- ción de la salud. El estilo de vida se relaciona con la percepción que los adolescentes tienen de su salud.[Abstract] This work he examines the property of lifestyle in the perception of health. I object the population of study he is composed of 1109 students of 10 to 16 years that they enjoy in two Spanish communities’s half way rural. In the study we have utilized like instrument of work the questionnaire Self Administered Physical Activity Checklist (SAPAC) adapted to the Spanish population. We utilized des- criptive fellow’s analysis, to the analysis infe- rencial and the test of contrast Chi cuadrado (x2). Aftermath demonstrated the existence of differences in the perception of health in terms of the sex (p=.000), of age (p=.000) and of the dwelling place (p=.015). Of equal form the television consumption (p =.029), the time dedicated to the computer (p =.034), the time dedicated to the school tasks (p =.034) and the accomplishment of physical activity (p =.000) they relate to the perception of the health. Lifestyle relates with the perception that the teens have of his health

Closed-form Jones matrix of dual-polarized inverted-vee dipole antennas over lossy ground

This paper presents a closed-form expression for the Jones matrix of a dual-polarized inverted-vee dipole antenna based on the Lorentz reciprocity theorem and the basic rules of electromagnetic refraction. The expression is used to determine the intrinsic cross-polarization ratio (IXR) as a function of droop angle, position of the source in the sky, antenna height, frequency, and reflection coefficient of the underlying ground. The expression is verified using full-wave simulations with a method-of-moments solver, showing very good agreement. It explains the increase in the IXR when the antenna is placed over a perfect electric ground plane. This result is used to explain the polarization properties of the Square Kilometre Array Log-periodic Antenna. Through the LOw-Frequency ARray Low-Band Antenna (LOFAR-LBA), the importance of the size of the ground plane is explained. Finally, design consideration for high polarization purity antennas is discussed