Discrete coherent states for higher Landau levels

We consider the quantum dynamics of a charged particle evolving under the action of a constant homogeneous magnetic field, with emphasis on the discrete subgroups of the Heisenberg group (in the Euclidean case) and of the SL(2, R) group (in the Hyperbolic case). We investigate completeness properties of discrete coherent states associated with higher order Euclidean and hyperbolic Landau levels, partially extending classic results of Perelomov and of Bargmann, Butera, Girardello and Klauder. In the Euclidean case, our results follow from identifying the completeness problem with known results from the theory of Gabor frames. The results for the hyperbolic setting follow by using a combination of methods from coherent states, time-scale analysis and the theory of Fuchsian groups and their associated automorphic forms.Comment: Revised for Annals of Physic

Impactos sociais: o emprego na agricultura irrigada de Guaíra, SP.

bitstream/item/86869/1/1994FL-001.pdfEste trabalho é uma reelaboração de parte da dissertação de Mestrado "Transformações Tecnológicas na Agricultura: Processo de Trabalho e Relações Sociais", apresentada pela autora no IFCH/UNICAMP - ABREU, L. S. de Transformações tecnologicas na agricultura : processo de trabalho e relações sociais em Guaira (SP). Dissertação (Mestrado). IFCH/UNICAMP. 1994

Comparing Organic Urban Consumers in Developing and Developed Countries: First Results in Brazil and France

Despite numerous studies reporting on sustainable consumption or organic consumer profiles, there is a gap in thorough understanding of organic consumers in different places, since most of studies only investigate organic consumption in most developed countries. The goal of this paper is thus to compare French and Brazilian organic consumers, so as to know if people think and behave differently or similarly in different places. Individual interviews were conducted in each country, with consumers in organic producers market in Brazil, and consumers who buy organic products from farmers markets or local organic food network in France. Products were selected to cover examples of different choice situations such as imported organic products that compete with comparable products of local origin, or organic local products in supermarkets that compete with similar products from other distribution outlets. Results show common consumer concerns such as quality or personal and family health, and common preference for local and organic products but for different reasons. However, results also shed light on different patterns related to environmental concerns or commitment to supporting small or local farmers. The impacts of the findings of this study relate to a diversity of topics such as social mobilization for sustainable agriculture, local organic food networks and environmental concerns. ...French Abstract : De nombreuses recherches portent sur la consommation durable et le profil des consommateurs de produits biologiques, mais ces recherches portent sur la consommation dans les pays développés, et ne permettent pas de savoir s'il existe des différences de consommation entre pays développés et pays en développement. Le but de cet article est de comparer le comportement de consommateurs de produits biologiques en France et au Brésil, sur la base d'entretiens individuels permettant de comparer plusieurs situations de choix : produits biologiques importés en concurrence avec des produits locaux comparables, produits biologiques locaux disponibles en supermarché ou d'en d'autres circuits de distribution,... Les résultats mettent en évidence des attentes communes, comme la qualité ou la santé, et des préférences partagées pour les produits biologiques et locaux, mais pour des raisons différentes dans les deux échantillons. Les résultats montrent également que l'importance accordée aux préoccupations environnementales et au soutien aux petits producteurs locaux n'est pas la même dans les deux échantillons. Cette recherche conduit à des pistes de réflexion portant sur la mobilisation des consommateurs pour la consommation durable, les réseaux de production et consommation de produits biologiques et les préoccupations environnementales des consommateurs.ORGANIC FOOD; LOCAL FOOD; SUSTAINABLE CONSUMPTION; QUALITATIVE STUDY

Deconstructing double-barred galaxies in 2D and 3D. II. Two distinct groups of inner bars

The intrinsic photometric properties of inner and outer stellar bars within 17 double-barred galaxies are thoroughly studied through a photometric analysis consisting of: i) two-dimensional multi-component photometric decompositions, and ii) three-dimensional statistical deprojections for measuring the thickening of bars, thus retrieving their 3D shape. The results are compared with previous measurements obtained with the widely used analysis of integrated light. Large-scale bars in single- and double-barred systems show similar sizes, and inner bars may be longer than outer bars in different galaxies. We find two distinct groups of inner bars attending to their in-plane length and ellipticity, resulting in a bimodal behaviour for the inner/outer bar length ratio. Such bimodality is related neither to the properties of the host galaxy nor the dominant bulge, and it does not show a counterpart in the dimension off the disc plane. The group of long inner bars lays at the lower end of the outer bar length vs. ellipticity correlation, whereas the short inner bars are out of that relation. We suggest that this behaviour could be due to either a different nature of the inner discs from which the inner bars are dynamically formed, or a different assembly stage for the inner bars. This last possibility would imply that the dynamical assembly of inner bars is a slow process taking several Gyr to happen. We have also explored whether all large-scale bars are prone to develop an inner bar at some stage of their lives, possibility we cannot fully confirm or discard.Comment: 14 pages, 8 figures, 1 table. Accepted for publication in MNRA

The intrinsic three-dimensional shape of galactic bars

We present the first statistical study on the intrinsic three-dimensional (3D) shape of a sample of 83 galactic bars extracted from the CALIFA survey. We use the galaXYZ code to derive the bar intrinsic shape with a statistical approach. The method uses only the geometric information (ellipticities and position angles) of bars and discs obtained from a multi-component photometric decomposition of the galaxy surface-brightness distributions. We find that bars are predominantly prolate-triaxial ellipsoids (68%), with a small fraction of oblate-triaxial ellipsoids (32%). The typical flattening (intrinsic C/A semiaxis ratio) of the bars in our sample is 0.34, which matches well the typical intrinsic flattening of stellar discs at these galaxy masses. We demonstrate that, for prolate-triaxial bars, the intrinsic shape of bars depends on the galaxy Hubble type and stellar mass (bars in massive S0 galaxies are thicker and more circular than those in less massive spirals). The bar intrinsic shape correlates with bulge, disc, and bar parameters. In particular with the bulge-to-total (B/T) luminosity ratio, disc g-r color, and central surface brightness of the bar, confirming the tight link between bars and their host galaxies. Combining the probability distributions of the intrinsic shape of bulges and bars in our sample we show that 52% (16%) of bulges are thicker (flatter) than the surrounding bar at 1$\sigma$ level. We suggest that these percentages might be representative of the fraction of classical and disc-like bulges in our sample, respectively.Comment: 18 pages, 11 figures, accepted for publication in MNRA

Formes d'organisation de maraîchers organiques périurbains de São Paulo.

Le développement de l'agriculture organique au Brésil prend des formes multiples. Au travers de leur expérience de l'AO, dans une communauté proche de trois métropoles, de petits maraîchers d'Ibiúna (São Paulo) créent des entités collectives et expérimentent de nouvelles pratiques sociales. À partir d'entretiens et d'observations sur le terrain, nous montrons comment ces minifundios se sont, ou ont été, organisés pour développer l'AO dans un même territoire Nous identifions quatre formes sociales d'organisation, leurs dynamiques, leurs valeurs et leurs inter-relations. Nous discutons des éléments susceptibles de sécuriser leur reproduction sociale et de soutenir de nouvelles voies de développement

A dinâmica do desenvolvimento da agroecologia no Brasil e na América Latina.

Resumo: A agroecologia é fonte de inspiração para a construção de sistemas agroalimentares ecológicos, a partir de 2003, foi fortalecida através de políticas públicas. O objetivo do artigo é o de apresentar as características, os elementos históricos determinantes da dinâmica de desenvolvimento da agroecologia no Brasil e em alguns países da América Latina, bem como suas diferentes facetas e o estado atual de sua estruturação. A metodologia utilizada é fruto de uma revisão bibliográfica, análise compreensiva de natureza sociológica e agronômica de um conjunto de estudos de casos. A agroecologia é atualmente legitimada pelo movimento social, redes científicas e técnicas, num cenário de tensão permanente e, de coexistência com a agricultura denominada de convencional ou produtivista