Reflexões E Teorias Sobre O Lazer - Um Roteiro Para A Geografia

Leisure activities became a human need and provide a myriad of meanings that can be read throughout space and time. As a social activity it consumes and develops in space and for individuals. In this article we intend to address the main similarities between tourism approaches, leisure and geography, by analyzing the theories, procedures and the nature of research. We portray the state of the art in top researches involving Leisure and Geography and searching for contributions in other areas. The theoretical framework is worked in the light of some of the most common geography concepts such as place, landscape and region, drawing opportunities of study for each concept. It articulates, through the most common theoretical-conceptual constructions in other areas, especially in the contributions of sociology, anthropology and economics. Part of the article is a series of proposals to encourage studies in different subfields of geography, including Economic Geography, Geography of Tourism and Cultural Geography. By drawing parallels between leisure and the different branches of Geographical knowledge, it culminates in a schematic proposal for studies of Geography and Leisure through the synthesis of categories and a theoretical framework proposal for each of them. It concludes with considerations about the potential and limitations of the studies in Geography having leisure as an object.379110

On the origin and evolution of the material in 67P/Churyumov-Gerasimenko

International audiencePrimitive objects like comets hold important information on the material that formed our solar system. Several comets have been visited by spacecraft and many more have been observed through Earth- and space-based telescopes. Still our understanding remains limited. Molecular abundances in comets have been shown to be similar to interstellar ices and thus indicate that common processes and conditions were involved in their formation. The samples returned by the Stardust mission to comet Wild 2 showed that the bulk refractory material was processed by high temperatures in the vicinity of the early sun. The recent Rosetta mission acquired a wealth of new data on the composition of comet 67P/Churyumov-Gerasimenko (hereafter 67P/C-G) and complemented earlier observations of other comets. The isotopic, elemental, and molecular abundances of the volatile, semi-volatile, and refractory phases brought many new insights into the origin and processing of the incorporated material. The emerging picture after Rosetta is that at least part of the volatile material was formed before the solar system and that cometary nuclei agglomerated over a wide range of heliocentric distances, different from where they are found today. Deviations from bulk solar system abundances indicate that the material was not fully homogenized at the location of comet formation, despite the radial mixing implied by the Stardust results. Post-formation evolution of the material might play an important role, which further complicates the picture. This paper discusses these major findings of the Rosetta mission with respect to the origin of the material and puts them in the context of what we know from other comets and solar system objects