An N2: CH4: H2O DC glow discharge plasma probed by optical and electric techniques: significance to the radiation chemistry of Titan's upper atmosphere in the presence of meteoritic water

This paper presents optical and electrical measurements on plasma generated by DC excited glow discharges in mixtures composed of 95% N2, 4.8% CH4 and 0.2% H2O at pressures varying from 1.064 mbar to 4.0 mbar. The discharges simulate the chemical reactions that may occur in Titan's atmosphere in the presence of meteorites and ice debris coming from Saturn's systems, assisted by cosmic rays and high energy charged particles. The results obtained from actinometric optical emission spectroscopy, combined with the results from a pulsed Langmuir probe, show that chemical species CH, CN, NH and OH are important precursors in the synthesis of the final solid products and that the chemical kinetics is essentially driven by electronic collision processes. It is shown that the presence of water is sufficient to produce complex solid products whose components are important in prebiotic compound synthesis. © 1998 Elsevier Science Ltd. All rights reserved.

On the stability of hypothetical satellites coorbital to Mimas or Enceladus

In the present work, we study the stability of hypothetical satellites that are coorbital with Enceladus and Mimas. We performed numerical simulations of 50 particles around the triangular Lagrangian equilibrium points of Enceladus and Mimas taking into account the perturbation of Mimas, Enceladus, Tethys, Dione, Titan and the oblateness of Saturn. All particles remain on tadpole orbits after 10 000 yr of integration. Since in the past the orbit of Enceladus and Mimas expanded due to the tidal perturbation, we also simulated the system with Enceladus and Mimas at several different values of semimajor axes. The results show that in general the particles remain on tadpole orbits. The exceptions occur when Enceladus is at semimajor axes that correspond to 6:7, 5:6 and 4:5 resonances with Mimas. Therefore, if Enceladus and Mimas had satellites librating around their Lagrangian triangular points in the past, they would have been removed if Enceladus crossed one of these first-order resonances with Mimas.

Dinâmica e estabilidade de satélites regulares como consequência da migração planetária

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização da técnica VxIAT para a determinação de volumes de precipitação na área central do Estado de São Paulo

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Sobre a idade das crises: as inter-relações sujeito-identidade-feminismo na pós-modernidade

This essay intends to think critically and theoretically on the interrelations among subject, identity, and Feminism in the context of Postmodernity, a context which will be herein denominated ―Age of Crises. These three aspects will be approached under a Historical perspective and put into question in a philosophical sight guided by Post-structuralistic theories, especially Derridian Deconstruction. In general, the main objective is to reach into a discussion about the undecidable inter-relation between Feminist thinking and Postmodernity, which is one of the configurations of the many contemporary crises. In order to do so, it will be necessary a previous discussion on the postmodern subject and its identity. This discussion will open up the possibility of contextualizing and discussing Feminism inside the intended objective. This discussion will be structured around the word ―crises which, in a compositional relation to the word ―age, will be taken as a synonym for ―Postmodernity and ―contemporary. ―Age of Crises, ―Postmodernity, ―contemporary, and ―Feminism will be words haunted by the phármakon phenomenon, a key aspect for Derridian Deconstruction, which will be the gravitational force that approximates and separates, in an undecidable relation, those signs.

Sobre O tronco, romance de Bernardo Élis

The conception of O tronco was influenced by Hegel´s ideas. The genesis of this novel is in Bernardo Élis’ purpose of writing a monograph on land ownership conflicts in Goiás, later transformed into a new project, the novel O tronco. The same ideological position of the author gives the argumentative direction of the novel; his ideological background determines the choice of the theme, associated with images expanded by the procedures of argumentation that permeate the literary discourse. Thus, in face of the undeniable aesthetic value of Élis´work, we analyzed O tronco, specifically the argumentation that guides the literary narrative, enhanced by the artistic treatment of violence, its theme, as the result of the struggle for power. The novel was published in 1956; the author, heir to the literary regionalism of the 30s, through an artistic and calculated combination of the story of a local government and literature, accuses, judges the exacerbated domination of a particular social group in a region in Goiás.

O estudante endiabrado: representação do mito de Dom Juan em espronceda

The present study is a reflection on the representation of the literary myth of Dom Juan in the work El estudiante de Salamanca (1836-1840), by Joseph de Espronceda. It highlights the most significant aspects of their recreation donjuanesca, since the classic elements taken from the founding work of Tirso de Molina to Romantic Titan which characterizes Dom Félix de Montemar.

Raman Lidar monitors emissions from sugar cane fires in the State of São Paulo: a pilot-project integrating radar, sodar, aerosol and gas observations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Climatologia de tempestades na área central do Estado de São Paulo usando radar meteorológico

A climatological characterization of storm properties during two summer seasons, viz. 1998-1999 and 1999-2000, based on observations from the Bauru S-band Doppler radar, was obtained from the TITAN Software of the National Center for Atmospheric Research (Boulder, Co), implemented at IPMet. Parameters, such as mean volume, mean area, mean and maximum echo tops, mean and maximum reflectivity, as well as speed and direction of precipitating systems were determined using the reflectivity >25, 30 and 40 dBZ and a volume >30 km3 as thresholds for storm identification. For the first time, the spatial distributions of these parameters were determined in the central State of São Paulo, based on radar observations. It was found that some preferential areas, where most of the convective activity was concentrated during the study period, were located along the Tietê River. The mean maximum reflectivity field has highlighted preferential regions for convection to develop over the metropolitan area of Campinas, which in turn was reinforced by the distribution of the echo tops and reflectivity >40 dBZ.