Thermodynamics from a scaling Hamiltonian

There are problems with defining the thermodynamic limit of systems with long-range interactions; as a result, the thermodynamic behavior of these types of systems is anomalous. In the present work, we review some concepts from both extensive and nonextensive thermodynamic perspectives. We use a model, whose Hamiltonian takes into account spins ferromagnetically coupled in a chain via a power law that decays at large interparticle distance $r$ as $1/r^{\alpha}$ for $\alpha\geq0$. Here, we review old nonextensive scaling. In addition, we propose a new Hamiltonian scaled by $2\frac{(N/2)^{1-\alpha}-1}{1-\alpha}$ that explicitly includes symmetry of the lattice and dependence on the size, $N$, of the system. The new approach enabled us to improve upon previous results. A numerical test is conducted through Monte Carlo simulations. In the model, periodic boundary conditions are adopted to eliminate surface effects.Comment: 12 pages, 2 figures, submitted for publication to Phys. Rev.

Hombres e igualdad. ¿Para qué sirven los hombres? Valencia, un caso de análisis

El presente trabajo viene determinado por una pregunta básica inicial: ¿Es posible ejecutar políticas de igualdad sin hacer partícipes de las mismas a los hombres? La nueva masculinidad, es un término relativamente reciente. Surge en el momento en el que ciertos feminismos -podríamos denominarlos avanzados-, valoran la necesidad de desarrollar nuevos planteamientos de igualdad de manera más recíprocamente bilateral. En este sentido, algunos autores plantean la cuestión de repensar el discurso hegemónico masculino. Se vehiculiza, pues, a través de los movimientos sociales de nuevos varones que, sin embargo, tropiezan con las estructuras sociales institucionalizadas, que muestran importantes resistencias al cambio de paradigma. Hemos indagado sobre la importancia que las políticas públicas tienen para la mejora de la satisfacción de la ciudadanía a nivel local. Así como la necesidad creciente de consolidación de las políticas de igualdad de género. Y, sobre todo -como plantean algunos teóricos- conocer el espacio que ocupan (o pueden hacerlo) en estas políticas el fomento de las nuevas masculinidades. Con el fin último de lograr vislumbrar si existe una demanda sentida y expresada por parte de la sociedad, para que los hombres participen corresponsablemente en las políticas de igualdad, si ésta es recogida y cómo por parte de las Administraciones Publicas

Temporal study of natural populations of Heterorhabditid and Steinernematid nematodes in horticultural crop soils

La dynamique des populations de nématodes entomopathogènes dans des sols horticoles a été étudiée par des prélèvements mensuels en huit sites de Catalogne (nord-est de l'Espagne) pendant 14 mois. Ces nématodes entomopathogènes ont été détectés dans six des huit sites et ont continué à l'être quels qu'aient été les traitements agricoles pratiqués sur ces sites. Pendant cette étude, les sites ont été labourés, détruisant ainsi l'habitat naturel des nématodes, puis laissés en jachère pendant plusieurs mois, sans que la présence des nématodes n'en paraisse affectée. Cependant, une influence saisonnière peut être observée, la présence des nématodes étant plus faible pendant les mois d'été où la température est élevée. Cette influence saisonnière apparaît également affecter la répartition verticale des nématodes qui migrent vers les couches plus profondes du sol, vraisemblablement pour éviter les effets néfastes de la température et du manque d'humidité. Les résultats de cette étude montrent que les populations naturelles de nématodes entomopathogènes sont capables de persister et de survivre dans le sol pendant de longues périodes en s'adaptant aux conditions fluctuantes et adverses de leur habitat naturel. (Résumé d'auteur

Emergent literacy beliefs in preschool and kindergarten contexts

This study aims to understand how a group of preschool/kindergarten teachers (N = 340) perceives and accomplishes linguistic and literacy oriented practices. Results show that, in a set of literacy and language tasks, teachers tend to value oral driven tasks and seldom engage in activities that relate to teaching the written language. This profile of educators is a reflection of prevalent views in pre-service teacher education and of some of the most common practices in Portuguese preschool and kindergarten classes (ages 3-6) and suggests that teachers have limited scientific knowledge of emergent literacy concepts. It seems that, despite being promoted to university training in the last 20 years, pre-service education does not yet reflect the state of the art in early childhood education. In a set of in-depth interviews (N = 8) we found a close association between the absence of literacy practices and the absence of pre-service specific knowledge about this subject. Participants that report consistent and regular linguistic and literacy oriented practices seem to perceive pre-service education as critical for their commitment to those practices. On the other hand, older teachers and teachers with lower training levels seem to undervalue specific literacy oriented tasks. The opposite seems to happen with younger and more educated teachers. Overall, our study suggests that the contents of pre-service and in-service education induce specific practices in preschool/kindergarten contexts, but it also suggests that this impact may be limited by socialization effects of dominant professional practices.Cette étude tente de comprendre comment un groupe d’enseignants du préscolaire/jardin d’enfants (N = 340) perçoit et accomplit les pratiques d’éveil à l’écrit. Les résultats montrent que, parmi un ensemble de tâches langagières, les enseignants ont tendance à favoriser les activités orales et ne s’engagent que rarement dans des activités relatives à l’enseignement de la langue écrite. Ce profil d’enseignants reflète des points de vues répandus dans la formation initiale des enseignants et quelques unes des pratiques les plus courantes dans le préscolaire portugais et les classes de jardin d’enfants (3-6 ans). Il suggère en outre que les enseignants ont une connaissance scientifique limitée des notions d’entrée dans l’écrit. Il semble donc que, malgré une prise en charge universitaire depuis ces 20 dernières années, la formation initiale des enseignants ne reflète pas encore l’état des connaissances acquises dans le champ de l’éducation de la petite enfance. Dans plusieurs entretiens (N = 8), nous avons relevé une relation étroite entre l’absence de pratiques d’éveil à l’écrit et l’absence de formation initiale spécifique sur ce sujet. Les enseignants qui déclarent mettre en oeuvre des pratiques d’éveil à l’écrit pertinentes et régulières semblent porter un regard critique sur la formation initiale. D’autre part, les enseignants plus âgés et ceux ayant bénéficié d’une moindre formation semblent sous-estimer les activités d’éveil à l’écrit, tandis que le contraire s’observe pour les enseignants plus jeunes et davantage formés. De façon générale, notre étude suggère que le contenu de la formation initiale et continue engendre des pratiques spécifiques dans le préscolaire/jardin d’enfants, mais elle suggère aussi que cet impact puisse être limité par des effets de socialisation en lien avec les pratiques professionnelles dominantes.Crenças sobre literacia emergente em contextos de jardim-de-infância e ensino pré-escolar RESUMO. Este estudo procura compreender de que forma um grupo de educadores do ensino pré-escolar (N = 340) concebe e leva a cabo práticas orientadas para a literacia e para o conhecimento da língua. Os resultados revelam que, num conjunto de tarefas linguísticas e de literacia, os educadores tendem a valorizar tarefas orais e raramente põem em prática actividades orientadas para o ensino da língua escrita. Este perfil de educadores reflecte uma visão dominante na formação inicial e algumas das práticas mais comuns nas salas de jardim-de-infância e ensino pré-escolar (idades 3-6), e sugere que os educadores têm um conhecimento limitado dos conceitos emergentes no que respeita à literacia. Parece que, apesar de ter sido promovida a formação universitária nos últimos 20 anos, a preparação dos educadores de infância ainda não reflecte os mais recentes desenvolvimentos na educação pré-escolar. Num conjunto de entrevistas aprofundadas (N = 8), descobrimos uma ligação estreita entre a ausência de práticas de literacia e a ausência de orientações específicas neste sentido durante a formação inicial. Os participantes que evidenciaram práticas linguísticas e de literacia consistentes e regulares parecem encarar a sua formação como tendo sido crucial para o seu envolvimento nessas práticas. Por outro lado, os educadores mais velhos, bem como aqueles com níveis de formação mais baixos, parecem subvalorizar as tarefas especificamente orientadas para a literacia. O contrário acontece com os educadores mais novos, ou com formação avançada. De uma maneira geral, o nosso estudo sugere que os conteúdos da formação incial e da formação contínua conduzem a práticas específicas nos contextos de educação pré-escolar, mas também sugere que este impacto pode ser limitado pelos efeitos de socialização das práticas profissionais dominantes.(undefined

Phenological and physiological responses to drought stress and subsequent rehydration cycles in two raspberry cultivars

AbstractRaspberry (Rubus idaeus L.) is a deciduous plant with perennial roots, 75% of which are concentrated in the upper level of the soil. Its shallow rooting system requires a regular water supply; a water deficit can affect fructification as well as cane growth and yield for the following season. Despite the demonstrated drought stress impact on the raspberry, there is little information about the phenological and physiological responses to drought stress. The main goal of this study was to evaluate the effects of drought stress on the phenological phases, physiological parameters and yield of two raspberry cultivars: Heritage (remontant type) and Meeker (non-remontant type). All plants were grown in pots under greenhouse conditions, and the following watering treatments were applied: (T1) well-watered, 100% irrigation and (T2) a controlled drought-stress cycle. The volumetric soil water content (θ), phenological phases, leaf net photosynthetic rate (A), transpiration rate (T), and stomatal conductance (gs) were registered periodically. The free proline and total soluble sugars were also determined. Based on the phenological study, Heritage under drought-stress (T2) showed earlier flowering and a shorter fruit production period in relation to well-watered plants (T1). In Meeker, T2 extended the cane and summer lateral elongation, showing earlier senescence. Leaf gas exchange decreased with drought stress, A declined after 28-day period under drought stress, from 9.2μmolCO2m−2s−1 to 3.0μmolCO2m−2s−1 in Heritage, and from 12.2μmolCO2m−2s−1 to 3.0μmolCO2m−2s−1 in Meeker. In both cultivars, the free proline and total soluble sugars increased with drought stress. The fruit production was also affected in the next season under T2 condition, decreasing in 34 and 38% in relation to well-watered plants

The Ljapunov-Schmidt reduction for some critical problems

This is a survey about the application of the Ljapunov-Schmidt reduction for some critical problems

JUANITA CONCEPCIÓN VERGARA [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201