Delay of Gratification in Costa Rican Preschoolers: Effect of Trust in the Experimenter and the Socio-Economic Status: Postergación de la gratificación en preescolares costarricenses: efecto de la confianza en el experimentador y el estatus socioeconómico

This study analyzed the effect of confidence in the experimenter on the performance of a group of Costa Rican preschoolers on self-control. In addition, the effect of socioeconomic status on performance on the marshmallow task was analyzed by a comparison of children from both different schools (public vs private) and different socioeconomic contexts within each school. The sample of participants was 67 children (26 girls, M of age = 63 months, SD = 6.03). Effects were found, both of the confidence in the experimenter and of the socio-economic status in self-control. The implications of this study for future studies with children and families are discussed.Este estudio analizó el efecto de la confianza en la persona experimentadora sobre el desempeño de un grupo de niñas(os) preescolares costarricenses en el autocontrol. Adicionalmente, se analizó el efecto del estatus socioeconómico en el desempeño en la tarea de la golosina por medio de una comparación de niños provenientes tanto de diferentes escuelas (pública vs privada) como de distintos contextos socioeconómicos al interior de cada escuela. La muestra de participantes fue de 67 niños(as) (26 niñas, M de edad = 63 meses, D.T. = 6.03). Se encontraron efectos, tanto de la confianza en la persona experimentadora, como del contexto socioeconómico en el autocontrol. Se discuten las implicaciones de este estudio para futuros trabajos con niñas y niños, y familias

Promovendo a capacidade de autocontrole em crianças: conceitos, e estratégias no contexto

This essay aims to show and discuss key aspects of child self-control based on recent research, as well as to propose factors and strategies to promote the development of this important capacity. To do this, he begins by defining self-control, then identifies some of its benefits, then describes the marshmallow test, as well as its analysis in context. Then it relates self-control with decision-making, analyzes the role of trust, the role of adults in its promotion in girls and boys, and finally proposes some strategies to support it.El presente ensayo tiene el objetivo de mostrar y discutir aspectos clave del autocontrol infantil con base en investigación reciente, así como plantear factores y estrategias para promover el desarrollo de esta importante capacidad. Para ello inicia definiendo el autocontrol, luego identifica algunos de sus beneficios, seguidamente describe el test de la golosina y su análisis en contexto. Luego relaciona el autocontrol con la toma de decisiones, analiza el papel de la confianza, el rol de las personas adultas en su fomento en niñas y niños, y finalmente plantea algunas estrategias para apoyarlo.Este ensaio tem como objetivo mostrar e discutir aspectos-chave do autocontrole infantil com base em pesquisas recentes, bem como propor fatores e estratégias para promover o desenvolvimento dessa importante capacidade. Para isso, ele começa definindo o autocontrole, depois identifica alguns de seus benefícios, depois descreve o teste de doces, bem como sua análise em contexto. Em seguida, relaciona o autocontrole com a tomada de decisão, analisa o papel da confiança, o papel dos adultos em sua promoção em meninas e meninos, e finalmente propõe algumas estratégias para apoiá-la

The free-volume structure of a polymer melt, poly(vinyl methylether) from molecular dynamics simulations and cavity analysis

10 pages, 6 figures, 2 tables.In this work we analyze and compare the free volume of a polymer system poly(vinyl methylether) (PVME) at 300 K obtained by the two direct but different approaches: Positron annihilation lifetime spectroscopy (PALS) and computer simulations. The free volume is calculated from the simulated cells of PVME by means of numerical methods based on grid scanning and probing the structure with a probe of a given radius RP. The free-volume structure was found to be percolated for small probes at RP=0.53 Å. As the probe radius increases, the cavity structure breaks into isolated cavities, reaching a maximum of the cavity number at RP=0.78 Å. We further develop methods for a geometrical analysis of the free-volume cavities by considering their shape. The geometrical computations show that the cavities have elongated shape with side-to-length ratio corresponding to approximately 1:0.55 and with an average length of 6 Å. Based on the overlap between the computed cavities and simplified geometrical representations, the best match of the cavity shape is obtained for the approximation to the ellipsoidal shape (overlap on 84.4%). A match with other examined shapes follows the sequence: ellipsoid>cylinder>bar>sphere>cube. Finally, the computed geometrical parameters are used as input parameters into the quantum-mechanical models for the orthopositronium (o-Ps) lifetime in various free-volume hole geometries. Comparison with the experimental data gives support for two ideas about the existence of an o-Ps particle in the polymeric matrix: (i) the positronium cannot localize in a portion of very small cavities; (ii) and in the case of the percolated cavities, several o-Ps particles occupy some subcavities in the same cavity. Additionally, radial distribution functions of the free volume indicate the existence of two kinds of free volume, a structured one, corresponding to interstitial spaces along the polymer chain, and the so-called “bulk free volume,” distributed randomly in the structure. PALS measurements seem to be mainly related with this bulk free volume. The cavities represented by the idealized geometries are visualized in three-dimensional space providing a unique representation on the free-volume structures.This work was supported by the VEGA Agency, Slovakia under Grant No. 2/0014/09(J.B.)and Project No. MAT2007-63681 (Spanish Ministry of Education), Grant No. IT-436-07 (Basque Government) and Project No. 2007SK0008 between Slovak Academy of Sciences (SAS) and Spanish Research Council (CSIC) Support from the project Spanish MEC Grant No. CSD2006-53 is also acknowledged.Peer reviewe

Promovendo a capacidade de autocontrole em crianças: conceitos, e estratégias no contexto

This essay aims to show and discuss key aspects of child self-control based on recent research, as well as to propose factors and strategies to promote the development of this important capacity. To do this, he begins by defining self-control, then identifies some of its benefits, then describes the marshmallow test, as well as its analysis in context. Then it relates self-control with decision-making, analyzes the role of trust, the role of adults in its promotion in girls and boys, and finally proposes some strategies to support it.El presente ensayo tiene el objetivo de mostrar y discutir aspectos clave del autocontrol infantil con base en investigación reciente, así como plantear factores y estrategias para promover el desarrollo de esta importante capacidad. Para ello inicia definiendo el autocontrol, luego identifica algunos de sus beneficios, seguidamente describe el test de la golosina y su análisis en contexto. Luego relaciona el autocontrol con la toma de decisiones, analiza el papel de la confianza, el rol de las personas adultas en su fomento en niñas y niños, y finalmente plantea algunas estrategias para apoyarlo.Este ensaio tem como objetivo mostrar e discutir aspectos-chave do autocontrole infantil com base em pesquisas recentes, bem como propor fatores e estratégias para promover o desenvolvimento dessa importante capacidade. Para isso, ele começa definindo o autocontrole, depois identifica alguns de seus benefícios, depois descreve o teste de doces, bem como sua análise em contexto. Em seguida, relaciona o autocontrole com a tomada de decisão, analisa o papel da confiança, o papel dos adultos em sua promoção em meninas e meninos, e finalmente propõe algumas estratégias para apoiá-la

Do pharmaceuticals bioaccumulate in marine mollusks and fish from a coastal lagoon?

Postprin