Laboratory-device configurations for investigating new dusty-plasma equilibria

Two configurations that are designed for laboratory investigations of dusty-plasma equilibria are being prepared for operation. The first configuration has a vertical magnetic field that confines horizontally a vertically oriented, 6.4 cm diameter, low-temperature, alkali-metal-ion plasma column. The plasma is produced via the Q-machine method (Rynn and D\u27Angelo 1960 Rev. Sci. Instrum. 31 1326) with contact-ionized alkali-metal ions and thermionically emitted electrons. The dust grains will be injected to form a small number of horizontal dusty-plasma layers levitated electrostatically above the plasma sheath. The advantage of using a Q-machine plasma source is the insensitivity of its plasma production to the background pressure of neutral particles. The plan is to study the competition between neutral-particle cooling and streaming-ion energization in dusty-plasma crystallization and decrystallization (i.e., freezing and melting) over a wide range of neutral-particle pressure. The second configuration has a large vacuum chamber (2 m diameter, 4 m length) and a large, solenoidal, magnetic field (0.1 T) that will magnetically confine small-diameter dust grains in a large-volume dusty plasma. The advantage of producing a large-volume, dusty plasma in a strong magnetic field is the ability to meet the criterion that the dust gyroradius is much smaller than the dusty-plasma-column diameter. The plan is to study third-component effects in microinstabilities and the influence of size distribution on magnetized dusty-plasma equilibrium and stability

Snapshots of the EYES project

The EYES project (IST-2001-34734) is a three years European research project on self-organizing and collaborative energy-efficient sensor networks. It addresses the convergence of distributed information processing, wireless communications, and mobile computing. The goal of the project is to develop the architecture and the technology which enables the creation of a new generation of sensors that can effectively network together so as to provide a flexible platform for the support of a large variety of mobile sensor network applications. This paper provides a broad overview of the EYES project and highlights some approaches and results of the architecture

The role of L1 use for L1 attrition

While the factor ‘language contact’ is often named among the most important for the development of individual language attrition, empirical validations of this claim are few and far between. This contribution argues that a bilingual’s use of the first language comprises very diverse situations which cannot be subsumed under one predictor variable. Grosjean’s (2001) framework of language modes is invoked as a useful way of structuring the use of the L1 by immigrants. A statistical investigation of these different types of L1 use on the one hand and language proficiency data on the other demonstrates that the impact of both active and passive exposure to the first language on attrition is anything but straightforward

Escher: Arte e Matemática desenhadas por alunos portugueses

Parte substancial da obra de Escher é dedicada ao estudo do Plano Euclidiano, nomeadamente numa perspetiva de o pavimentar. É sobre este tópico da obra de Escher que incide o presente trabalho o qual pode ser encardao como um ‘tributo’ a Escher e à sua arte. À semelhança de muitos outros já existentes na literatura, este trabalho retrata a harmonia e afinidade existente entre a Arte e a Matemática nas criações do artista. Porém, face a algumas particularidades, julgamos que o nosso estudo prima por alguma singularidade, sendo exemplo elucidativo da expressão gráfica nas Artes Visuais e na Matemática, associado ao relato de uma experiência vivida em contexo escolar. Sustentando-se numa análise e apresentação cuidada dos procedimentos seguidos por Escher para pavimentar o plano, um grupo de alunos em risco de abandono escolar (com idades compreendidas entre os 16 e os 19 anos que não tinham concluído o ensino básico), (re)criou a obra de Escher em painéis de azulejo, mediante produções artísticas originais

Da Arte à Matemática… da Matemática à Arte: uma experiência no Ensino Português

The struggling on identifying strategies and factors that could help to improve the teaching/learning process, regarding the existence of multiple realities, is a subject much discussed in literature. Finding new ways of answer challenges which we came across, is the main reason why this study has been made. The primary goal is centred in applying a Geometry curriculum including many different learning situations based in vocational training. The students were between 16 and 19 years old. Making use of Art is analysed as a potential method to improve Mathematics teaching. Being Escher’s work an element of undiscussable richness with highlights to “Exploration Tessellations”, an investigation has been made to show how some Escher’s works could be a starting point to the introduction of mathematical concepts/contents. It was noticed in a further case that using Art could lead not just to the student’s effective cooperation in the teaching/learning process, as could be a very strong acquisition and way to apply new solid mathematical concepts

Study of the f2(1270)f_2(1270), f2′(1525)f_2'(1525), f0(1370)f_0(1370) and f0(1710)f_0(1710) in the J/ψJ/\psi radiative decays

In this paper we present an approach to study the radiative decay modes of the $J/\psi$ into a photon and one of the tensor mesons $f_2(1270)$, $f'_2(1525)$, as well as the scalar ones $f_0(1370)$ and $f_0(1710)$. Especially we compare predictions that emerge from a scheme where the states appear dynamically in the solution of vector meson--vector meson scattering amplitudes to those from a (admittedly naive) quark model. We provide evidence that it might be possible to distinguish amongst the two scenarios, once improved data are available.Comment: The large Nc argument improved; version published in EPJA

Study of the reaction pbar p -> phi phi from 1.1 to 2.0 GeV/c

A study has been performed of the reaction pbar p -> 4K using in-flight antiprotons from 1.1 to 2.0 GeV/c incident momentum interacting with a hydrogen jet target. The reaction is dominated by the production of a pair of phi mesons. The pbar p -> phi phi cross section rises sharply above threshold and then falls continuously as a function of increasing antiproton momentum. The overall magnitude of the cross section exceeds expectations from a simple application of the OZI rule by two orders of magnitude. In a fine scan around the xi/f_J(2230) resonance, no structure is observed. A limit is set for the double branching ratio B(xi -> pbar p) * B(xi -> phi phi) < 6e-5 for a spin 2 resonance of M = 2.235 GeV and Width = 15 MeV.Comment: 13 pages, 13 figures, 2 tables, Latex. To be published in Phys. Rev.

Efectos de un programa de eliminación de sujeciones físicas sobre personas mayores con demencia en residencias

Objetivo: Analizar los resultados de eliminar las sujeciones físicas en mayores con demencia que viven en residencias. Este objetivo se enmarca en un proceso más amplio de modificación del modelo de atención residencial. Método: Estudio cuasi experimental en dos residencias desde mayo de 2010 hasta mayo de 2012. Se recoge información en 7 momentos temporales y se efectúa un análisis longitudinal. Tras formar al personal se retiraron progresivamente las sujeciones físicas en el centro El Puig, mientras que en el centro Conarda se mantuvieron las sujeciones. Las variables principales medidas fueron: caídas, psicofármacos administrados, así como diversos indicadores de estado mental y funcional (Norton, NPI, Minimental,Tinetti, Barthel).Resultados: En el centro en el que se eliminan todas las sujeciones físicas (El Puig), se observa una ligera mejoría en el número de caídas y sus consecuencias mejoran levemente, aunque no son estadísticamente significativas. Los ANOVA mostraron mejoras significativas en el centro que ha eliminado las sujeciones respecto a la prescripción de psicofármacos, al deterioro cognitivo y a las alteraciones de conducta.Discusión: Se constata que retirar sujeciones físicas no repercute negativamente en las caídas y sin embargo mejora ciertos aspectos del bienestar y la autonomía de los mayores (alteraciones de conducta y deterioro mental). Además, se evidencia que este programa debe ser complementado con un programa de desatar químico (retirada de psicofármacos)