934 resultados para ACTIVITY THEORY
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Hispanic teens are a high-risk population for initiation of early sexual activity and alcohol use which in turn has numerous social and health consequences. One strategy to address prevention of these behaviors is to implement a capacity building intervention that promotes parent child communication, encompasses their cultural values and community participation. This study describes the process evaluation of a pilot intervention program amongst Hispanic teens and their families living along the Texas-Mexico border. “Girls Lets Talk” is a small group intervention with 10-14 year old teens and their female adult family members that involves education regarding effects of alcohol use and sexual activity as well as activities for monitoring and refusal skills to prevent risky behaviors. Two waves of the program each consisting of at least seven mother daughter dyads were conducted. During the designing process, community advisory board meetings and focus groups were held to review course materials and ensure they were appropriate to the Mexican American culture. Parent and adolescent surveys were administered at the beginning and end of the intervention to assess for psychosocial outcome variables. All sessions received high mean satisfactory scores (mean of 4.00 or better on a five point scale) for both adult and adolescent participants. Qualitative feedback was obtained via debriefing sessions to evaluate experience as well as alter recruitment strategies. A Wilcoxon Sign Rank analysis of the pre and post intervention surveys was done that showed significant changes in some outcome variables such as intentions and confidence for monitoring behaviors for adults and beliefs regarding sexual activity. “Girls Lets Talk” is a promising example of how a process evaluation plan can help develop a theory based health promotion program using the community based participatory research approach. The intervention may also be effective in altering intentions and enhancing self-efficacy among parents and teens in order to decrease risky behaviors such as early sexual activity and alcohol use.^
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Background. This study was designed to evaluate the effects of the Young Leaders for Healthy Change program, an internet-delivered program in the school setting that emphasized health advocacy skills-development, on nutrition and physical activity behaviors among older adolescents (13–18 years). The program consisted of online curricular modules, training modules, social media, peer and parental support, and a community service project. Module content was developed based on Social Cognitive Theory and known determinants of behavior for older adolescents. ^ Methods. Of the 283 students who participated in the fall 2011 YL program, 38 students participated in at least ten of the 12 weeks and were eligible for this study. This study used a single group-only pretest/posttest evaluation design. Participants were 68% female, 58% white/Caucasian, 74% 10th or 11th graders, and 89% mostly A and/or B students. The primary behavioral outcomes for this analysis were participation in 60-minutes of physical activity per day, 20-minutes of vigorous- or moderate- intensity physical activity (MVPA) participation per day, television and computer time, fruit and vegetable (FV) intake, sugar-sweetened beverage intake, and consumption of breakfast, home-cooked meals, and fast food. Other outcomes included knowledge, beliefs, and attitudes related to healthy eating, physical activity, and advocacy skills. ^ Findings. Among the 38 participants, no significant changes in any variables were observed. However, among those who did not previously meet behavioral goals there was an 89% increase in students who participated in more than 20 minutes of MVPA per day and a 58% increase in students who ate home-cooked meals 5–7 days per week. The majority of participants met program goals related to knowledge, beliefs, and attitudes prior to the start of the program. Participants reported either maintaining or improving to the goal at posttest for all items except FV intake knowledge, taste and affordability of healthy foods, interest in teaching others about being healthy, and ease of finding ways to advocate in the community. ^ Conclusions. The results of this evaluation indicated that promoting healthy behaviors requires different strategies than maintaining healthy behaviors among high school students. In the school setting, programs need to target the promotion and maintenance of health behaviors to engage all students who participate in the program as part of a class or club activity. Tailoring the program using screening and modifying strategies to meet the needs of all students may increase the potential reach of the program. The Transtheoretical Model may provide information on how to develop a tailored program. Additional research on how to utilize the constructs of TTM effectively among high school students needs to be conducted. Further evaluation studies should employ a more expansive evaluation to assess the long-term effectiveness of health advocacy programming.^
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A flowchart approach to industrial cluster policy emphasizes the importance ofthe ordering of policy measures. The flow of policy implementation is to establish an industrial zone, to invite an anchor company, and to promote its related companies to invest in the industrial zone. This article delineated "a flowchart approach to industrial cluster policy" by proposing sufficient conditions for forming industrial clusters typical in the manufacturing industry in Asia to enhance regional economic growth. The typical industrial cluster policy was theorized by defining an industrial zone as "quasi-public goods", and it was shown that the policy enhances economic growth under a production function of "increasing returns to scale" of an anchor company. Critical amounts of the production of "scale economies" that are used by the related companies to decide whether or not to invest in clusters were also shown.
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Research on multinational firms’ activity has been conducted widely since late 1980s. The literature is differentiated into three types: horizontal FDI, vertical FDI, and three-country FDI, represented by export platform FDI. There are other methods of differentiation of the literature by approach, for example, the pure theory approach represented by Krugman and Melitz and the numerical simulation approach represented by Markusen. This paper surveys Markusen type literature by firm type. There is little literature focused on intermediate goods trade, although intermediate goods trade is considered to be strongly related to the production patterns of MNEs. In this paper, we introduce a model to explicitly treat intermediate goods trade and present simulation analysis for empirical estimation.
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Alzheimer's disease (AD) is the most common cause of dementia. Over the last few years, a considerable effort has been devoted to exploring new biomarkers. Nevertheless, a better understanding of brain dynamics is still required to optimize therapeutic strategies. In this regard, the characterization of mild cognitive impairment (MCI) is crucial, due to the high conversion rate from MCI to AD. However, only a few studies have focused on the analysis of magnetoencephalographic (MEG) rhythms to characterize AD and MCI. In this study, we assess the ability of several parameters derived from information theory to describe spontaneous MEG activity from 36 AD patients, 18 MCI subjects and 26 controls. Three entropies (Shannon, Tsallis and Rényi entropies), one disequilibrium measure (based on Euclidean distance ED) and three statistical complexities (based on Lopez Ruiz–Mancini–Calbet complexity LMC) were used to estimate the irregularity and statistical complexity of MEG activity. Statistically significant differences between AD patients and controls were obtained with all parameters (p < 0.01). In addition, statistically significant differences between MCI subjects and controls were achieved by ED and LMC (p < 0.05). In order to assess the diagnostic ability of the parameters, a linear discriminant analysis with a leave-one-out cross-validation procedure was applied. The accuracies reached 83.9% and 65.9% to discriminate AD and MCI subjects from controls, respectively. Our findings suggest that MCI subjects exhibit an intermediate pattern of abnormalities between normal aging and AD. Furthermore, the proposed parameters provide a new description of brain dynamics in AD and MCI.
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This paper is an introduction of the regret theory-based scenario building approach combining with a modified Delphi method that uses an interactive process to design and assess four different TDM measures (i.e., cordon toll, parking charge, increased bus frequency and decreased bus fare). The case study of Madrid is used to present the analysis and provide policy recommendations. The new scenario building approach incorporates expert judgement and transport models in an interactive process. It consists of a two-round modified Delphi survey, which was answeared by a group of Spanish transport experts who were the participants of the Transport Engineering Congress (CIT 2012), and an integrated land-use and transport model (LUTI) for Madrid that is called MARS (Metropolitan Activity Relocation Simulator).
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El principio de Teoría de Juegos permite desarrollar modelos estocásticos de patrullaje multi-robot para proteger infraestructuras criticas. La protección de infraestructuras criticas representa un gran reto para los países al rededor del mundo, principalmente después de los ataques terroristas llevados a cabo la década pasada. En este documento el termino infraestructura hace referencia a aeropuertos, plantas nucleares u otros instalaciones. El problema de patrullaje se define como la actividad de patrullar un entorno determinado para monitorear cualquier actividad o sensar algunas variables ambientales. En esta actividad, un grupo de robots debe visitar un conjunto de puntos de interés definidos en un entorno en intervalos de tiempo irregulares con propósitos de seguridad. Los modelos de partullaje multi-robot son utilizados para resolver este problema. Hasta el momento existen trabajos que resuelven este problema utilizando diversos principios matemáticos. Los modelos de patrullaje multi-robot desarrollados en esos trabajos representan un gran avance en este campo de investigación. Sin embargo, los modelos con los mejores resultados no son viables para aplicaciones de seguridad debido a su naturaleza centralizada y determinista. Esta tesis presenta cinco modelos de patrullaje multi-robot distribuidos e impredecibles basados en modelos matemáticos de aprendizaje de Teoría de Juegos. El objetivo del desarrollo de estos modelos está en resolver los inconvenientes presentes en trabajos preliminares. Con esta finalidad, el problema de patrullaje multi-robot se formuló utilizando conceptos de Teoría de Grafos, en la cual se definieron varios juegos en cada vértice de un grafo. Los modelos de patrullaje multi-robot desarrollados en este trabajo de investigación se han validado y comparado con los mejores modelos disponibles en la literatura. Para llevar a cabo tanto la validación como la comparación se ha utilizado un simulador de patrullaje y un grupo de robots reales. Los resultados experimentales muestran que los modelos de patrullaje desarrollados en este trabajo de investigación trabajan mejor que modelos de trabajos previos en el 80% de 150 casos de estudio. Además de esto, estos modelos cuentan con varias características importantes tales como distribución, robustez, escalabilidad y dinamismo. Los avances logrados con este trabajo de investigación dan evidencia del potencial de Teoría de Juegos para desarrollar modelos de patrullaje útiles para proteger infraestructuras. ABSTRACT Game theory principle allows to developing stochastic multi-robot patrolling models to protect critical infrastructures. Critical infrastructures protection is a great concern for countries around the world, mainly due to terrorist attacks in the last decade. In this document, the term infrastructures includes airports, nuclear power plants, and many other facilities. The patrolling problem is defined as the activity of traversing a given environment to monitoring any activity or sensing some environmental variables If this activity were performed by a fleet of robots, they would have to visit some places of interest of an environment at irregular intervals of time for security purposes. This problem is solved using multi-robot patrolling models. To date, literature works have been solved this problem applying various mathematical principles.The multi-robot patrolling models developed in those works represent great advances in this field. However, the models that obtain the best results are unfeasible for security applications due to their centralized and predictable nature. This thesis presents five distributed and unpredictable multi-robot patrolling models based on mathematical learning models derived from Game Theory. These multi-robot patrolling models aim at overcoming the disadvantages of previous work. To this end, the multi-robot patrolling problem was formulated using concepts of Graph Theory to represent the environment. Several normal-form games were defined at each vertex of a graph in this formulation. The multi-robot patrolling models developed in this research work have been validated and compared with best ranked multi-robot patrolling models in the literature. Both validation and comparison were preformed by using both a patrolling simulator and real robots. Experimental results show that the multirobot patrolling models developed in this research work improve previous ones in as many as 80% of 150 cases of study. Moreover, these multi-robot patrolling models rely on several features to highlight in security applications such as distribution, robustness, scalability, and dynamism. The achievements obtained in this research work validate the potential of Game Theory to develop patrolling models to protect infrastructures.
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INTRODUCCIÓN: El riesgo de padecer enfermedades cardiovasculares y los índices de obesidad infantil han ido en aumento durante los últimos años empobreciendo la salud de la población. La Teoría de Barker relaciona el estado de salud de la madre con el desarrollo fetal, asociando a un deficiente estado físico y hábitos de vida negativos de la mujer embarazada con el aumento del riesgo de padecer cardiopatías en la infancia y adolescencia, así como predisponer al recién nacido a padecer sobrepeso y/u obesidad en su vida posterior. Por otro lado los estudios efectuados sobre ejercicio físico durante el embarazo reportan beneficios para salud materna y fetal. Uno de los parámetros más utilizados para comprobar la salud fetal es su frecuencia cardiaca, mediante la que se comprueba el buen desarrollo del sistema nervioso autónomo. Si se observa este parámetro en presencia de ejercicio materno podría encontrarse una respuesta crónica del corazón fetal al ejercicio materno como consecuencia de una adaptación y mejora en el funcionamiento del sistema nervioso autónomo del feto. De esta forma podría mejorar su salud cardiovascular intrauterina, lo que podría mantenerse en su vida posterior descendiendo el riesgo de padecer enfermedades cardiovasculares en la edad adulta. OBJETIVOS: Conocer la influencia de un programa de ejercicio físico supervisado en la frecuencia cardiaca fetal (FCF) en reposo y después del ejercicio materno en relación con gestantes sedentarias mediante la realización de un protocolo específico. Conocer la influencia de un programa de ejercicio físico en el desarrollo del sistema nervioso autónomo fetal, relacionado con el tiempo de recuperación de la FCF. MATERIAL Y MÉTODO: Se diseñó un ensayo clínico aleatorizado multicéntrico en el que participaron 81 gestantes (GC=38, GE=43). El estudio fue aprobado por el comité ético de los hospitales que participaron en el estudio. Todas las gestantes fueron informadas y firmaron un consentimiento para su participación en el estudio. Las participantes del GE recibieron una intervención basada en un programa de ejercicio físico desarrollado durante la gestación (12-36 semanas de gestación) con una frecuencia de tres veces por semana. Todas las gestantes realizaron un protocolo de medida de la FCF entre las semanas 34-36 de gestación. Dicho protocolo consistía en dos test llevados a cabo caminando a diferentes intensidades (40% y 60% de la frecuencia cardiaca de reserva). De este protocolo se obtuvieron las principales variables de estudio: FCF en reposo, FCF posejercicio al 40 y al 60% de intensidad, tiempo de recuperación de la frecuencia cardiaca fetal en ambos esfuerzos. El material utilizado para la realización del protocolo fue un monitor de frecuencia cardiaca para controlar la frecuencia cardiaca de la gestante y un monitor fetal inalámbrico (telemetría fetal) para registrar el latido fetal durante todo el protocolo. RESULTADOS: No se encontraron diferencias estadísticamente significativas en la FCF en reposo entre grupos (GE=140,88 lat/min vs GC= 141,95 lat/min; p>,05). Se encontraron diferencias estadísticamente significativas en el tiempo de recuperación de la FCF entre los fetos de ambos grupos (GE=135,65 s vs GC=426,11 s esfuerzo al 40%; p<,001); (GE=180,26 s vs GC=565,61 s esfuerzo al 60%; p<,001). Se encontraron diferencias estadísticamente significativas en la FCF posejercicio al 40% (GE=139,93 lat/min vs GC=147,87 lat/min; p<,01). No se encontraron diferencias estadísticamente significativas en la FCF posejercicio al 60% (GE=143,74 lat/min vs GC=148,08 lat/min; p>,05). CONLUSIÓN: El programa de ejercicio físico desarrollado durante la gestación influyó sobre el corazón fetal de los fetos de las gestantes del GE en relación con el tiempo de recuperación de la FCF. Los resultados muestran un posible mejor funcionamiento del sistema nervioso autónomo en fetos de gestantes activas durante el embarazo. ABSTRACT INTRODUCTION: The risk to suffer cardiovascular diseases and childhood obesity index has grown in the last years worsening the health around the population. Barker´s Theory related maternal health with fetal development establishing an association between a poorly physical state and an unhealthy lifestyle in the pregnant woman with the risk to suffer heart disease during childhood and adolescence, childhood overweight and/or obese is related to maternal lifestyle. By the other way researches carried out about physical exercise and pregnancy show benefits in maternal and fetal health. One of the most studied parameters to check fetal health is its heart rate, correct fetal autonomic nervous system development and work is also corroborated by fetal heart rate. Looking at this parameter during maternal exercise a chronic response of fetal heart could be found due to an adaptation and improvement in the working of the autonomic nervous system. Therefore its cardiovascular health could be enhanced during its intrauterine life and maybe it could be maintained in its posterior life descending the risk to suffer cardiovascular diseases in adult life. OBJECTIVES: To know the influence of a supervised physical activity program in the fetal heart rate (FHR) at rest, FHR after maternal exercise related to sedentary pregnant women by a FHR assessment protocol. To know the influence of a physical activity program in the development of the autonomic nervous system related to FHR recovery time. MATERIAL AND METHOD: A multicentric randomized clinical trial was design in which 81 pregnant women participated (CG=38, EG=43). The study was approved by the ethics committee of all of the hospitals participating in the study. All of the participants signed an informed consent for their participation in the study. EG participants received an intervention based on a physical activity program carried out during gestation (12-36 gestation weeks) with a three days a week frequency. All of the participants were tested between 34-36 weeks of gestation by a specific FHR assessment protocol. The mentioned protocol consisted in two test performed walking and at a two different intensities (40% and 60% of the reserve heart rate). From this protocol we obtained the main research variables: FHR at rest, FHR post-exercise at 40% and 60% intensity, and FHR recovery time at both walking test. The material used to perform the protocol were a FH monitor to check maternal HR and a wireless fetal monitor (Telemetry) to register fetal beats during the whole protocol. RESULTS: There were no statistical differences in FHR at rest between groups (EG=140,88 beats/min vs CG= 141,95 beats/min; p>,05). There were statistical differences in FHR recovery time in both walking tests between groups (EG=135,65 s vs CG=426,11 s test at 40% intensity; p<,001); (EG=180,26 s vs CG=565,61 s test at 60% intensity; p<,001). Statistical differences were found in FHR post-exercise at 40% intensity between groups (EG=139,93 beats/min vs CG=147,87 beats/min; p<,01). No statistical differences were found in FHR at rest post-exercise at 60% intensity between groups (EG=143,74 beats/min vs CG=148,08 beats/min; p>,05). CONCLUSIONS: The physical activity program performed during gestation had an influence in fetal heart of the fetus from mother in the EG related to FHR recovery time. These results show a possible enhancement on autonomic nervous system working in fetus from active mothers during gestation.
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We proposed in our previous work V-substituted In2S3 as an intermediate band (IB) material able to enhance the efficiency of photovoltaic cells by combining two photons to achieve a higher energy electron excitation, much like natural photosynthesis. Here this hyper-doped material is tested in a photocatalytic reaction using wavelength-controlled light. The results evidence its ability to use photons with wavelengths of up to 750 nm, i.e. with energy significantly lower than the bandgap (=2.0 eV) of non-substituted In2S3, driving with them the photocatalytic reaction at rates comparable to those of non-substituted In2S3 in its photoactivity range (λ ≤ 650 nm). Photoluminescence spectra evidence that the same bandgap excitation as in V-free In2S3 occurs in V-substituted In2S3 upon illumination with photons in the same sub-bandgap energy range which is effective in photocatalysis, and its linear dependence on light intensity proves that this is not due to a nonlinear optical property. This evidences for the first time that a two-photon process can be active in photocatalysis in a single-phase material. Quantum calculations using GW-type many-body perturbation theory suggest that the new band introduced in the In2S3 gap by V insertion is located closer to the conduction band than to the valence band, so that hot carriers produced by the two-photon process would be of electron type; they also show that the absorption coefficients of both transitions involving the IB are of significant and similar magnitude. The results imply that V-substituted In2S3, besides being photocatalytically active in the whole visible light range (a property which could be used for the production of solar fuels), could make possible photovoltaic cells of improved efficiency.
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We model experience-dependent plasticity in the cortical representation of whiskers (the barrel cortex) in normal adult rats, and in adult rats that were prenatally exposed to alcohol. Prenatal exposure to alcohol (PAE) caused marked deficits in experience-dependent plasticity in a cortical barrel-column. Cortical plasticity was induced by trimming all whiskers on one side of the face except two. This manipulation produces high activity from the intact whiskers that contrasts with low activity from the cut whiskers while avoiding any nerve damage. By a computational model, we show that the evolution of neuronal responses in a single barrel-column after this sensory bias is consistent with the synaptic modifications that follow the rules of the Bienenstock, Cooper, and Munro (BCM) theory. The BCM theory postulates that a neuron possesses a moving synaptic modification threshold, θM, that dictates whether the neuron's activity at any given instant will lead to strengthening or weakening of its input synapses. The current value of θM changes proportionally to the square of the neuron's activity averaged over some recent past. In the model of alcohol impaired cortex, the effective θM has been set to a level unattainable by the depressed levels of cortical activity leading to “impaired” synaptic plasticity that is consistent with experimental findings. Based on experimental and computational results, we discuss how elevated θM may be related to (i) reduced levels of neurotransmitters modulating plasticity, (ii) abnormally low expression of N-methyl-d-aspartate receptors (NMDARs), and (iii) the membrane translocation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in adult rat cortex subjected to prenatal alcohol exposure.
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Mixed enterprises, which are entities jointly owned by the public and private sector, are spreading all over Europe in local utilities. Well aware that in the vast majority of cases the preference of local authorities towards such governance structure is determined by practical reasons rather than by the ambition to implement new regulatory designs (an alternative to the typical “external” regulation), our purpose is to confer some scientific value to this phenomenon which has not been sufficiently investigated in the economic literature. This paper aims at proposing an economic analysis of mixed enterprises, especially of the specific configuration in which the public partner acts as controller and the private one (or “industrial” partner) as service provider. We suggest that the public service concession to mixed enterprises could embody, under certain conditions, a noteworthy substitute to the traditional public provision and the concession to totally private enterprises, as it can push regulated operators to outperform and limit the risk of private opportunism. The starting point of the entire analysis is that ownership allows the (public) owner to gather more information about the actual management of the firm, according to property rights theory. Following this stream of research, we conclude that under certain conditions mixed enterprises could significantly reduce asymmetric information between regulators and regulated firms by implementing a sort of “internal” regulation. With more information, in effect, the public authority (as owner/controller of the regulated firm, but also as member of the regulatory agency) can stimulate the private operator to be more efficient and can monitor it more effectively with respect to the fulfilment of contractual obligations (i.e., public service obligations, quality standards, etc.). Moreover, concerning the latter function, the board of directors of the mixed enterprise can be the suitable place where public and private representatives (respectively, welfare and profit maximisers) can meet to solve all disputes arising from incomplete contracts, without recourse to third parties. Finally, taking into account that a disproportionate public intervention in the “private” administration (or an ineffective protection of the general interest) would imply too many drawbacks, we draw some policy implications that make an equitable debate on the board of the firm feasible. Some empirical evidence is taken from the Italian water sector.
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"Supported in part by Contract No. U.S. AEC AT(11-1)-1018."
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"Edited by H. Collison."
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In some forms of tourism, and perhaps particularly in the case of special interest tourism, it can be argued that tourism encounters are service relationships with emotional attachment through the special interest focus and a level of enduring involvement on the part of participants. This involvement is two-fold. First, an interest with the activity; second, a sharing with like-minded people in a social world that extends from home to tourist destination and return. Intimacies in tourism can thus be interpreted through the model of the relationship cycle that comprises the stages A. Aquaintance, B, Buildup, C, Continuation and D, Dissolution. The paper builds upon this concept by utilising ideas of other-centred and self-centredness in personal relationships, and extends the concept of other-centredness to host environments. It also suggests that, in the academic literature about place, location may be secondary in that the quality of experience is primarily determined by the intimacies that exist between people at that place, especially that existing between visitors. © 2004 Published by Elsevier Ltd.
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An assumption of theory-based physical activity interventions is that active participation positively affects the theoretical constructs upon which the intervention is based. This assumption is rarely tested. This study assessed whether participation, defined as completion of homework, in a lifestyle physical activity intervention was associated with changes over 6 months in constructs the homework addressed: the behavioral and cognitive processes of change, self-efficacy, and decisional balance (the pros and cons). Participants were 244 sedentary adults aged 25 to 75 years. They completed an average of 12 of 20 homework assignments. Those completing at least two-thirds of the homework (n = 113) had greater changes in the theoretical constructs from pretest to posttest than those completing less (n = 90). Post-hoc analyses suggest that completing theory-based homework may impact the processes of change and self-efficacy in lifestyle physical activity interventions and, therefore, are warranted in future interventions.