Challenges and strategies of forest research and education for the 21st century: a Brazilian perspective.

Também publicado no The International Forestry Review, Oxford, v. 7, n. 5, p. 350, Aug. 2005. Resumo

Desenvolvimento florestal sustentável: requerimentos de uma sociedade.

O papel das florestas para o desenvolvimento da sociedade brasileira e mundial. Tendências mundiais associadas ao agronegócio de base florestal. Importância socioeconômica e ambiental do atual do setor florestal. O custo social de não se implementar atividades agropecuárias e florestais no Brasil. Bases internas de produção. Oportunidades no Mercado Internacional. Ações associadas às condicionantes administrativas e de legislação sobre o setor florestal. Ampliação da base florestal. Desenvolvimento científico e tecnológico do setor florestal. Conclusões e recomendações.bitstream/CNPF-2009-09/41570/1/doc138.pd

The 2D Distribution of Iron Rich Ejecta in the Remnant of SN 1885 in M31

We present Hubble Space Telescope (HST) ultraviolet Fe I and Fe II images of the remnant of Supernova 1885 (S And) which is observed in absorption against the bulge of the Andromeda galaxy, M31. We compare these Fe I and Fe II absorption line images to previous HST absorption images of S And, of which the highest quality and theoretically cleanest is Ca II H & K. Because the remnant is still in free expansion, these images provide a 2D look at the distribution of iron synthesized in this probable Type Ia explosion, thus providing insights and constraints for theoretical SN Ia models. The Fe I images show extended absorption offset to the east from the remnant's center as defined by Ca II images and is likely an ionization effect due to self-shielding. More significant is the remnant's apparent Fe II distribution which consists of four streams or plumes of Fe-rich material seen in absorption that extend from remnant center out to about 10,000 km/s. This is in contrast to the remnant's Ca II absorption, which is concentrated in a clumpy, roughly spherical shell at 1000 to 5000 km/s but which extends out to 12,500 km/s. The observed distributions of Ca and Fe rich ejecta in the SN 1885 remnant are consistent with delayed detonation white dwarf models. The largely spherical symmetry of the Ca-rich layer argues against a highly anisotropic explosion as might result from a violent merger of two white dwarfs.Comment: 14 pages, 8 figures, and 1 table; revised to match ApJ published versio

Pesquisa agroflorestal no contexto brasileiro.

Trabalho apresentado no Seminario eucalipto: uma visao global, 1995, Belo Horizonte

Explosion Models for Type Ia Supernovae: A Comparison with Observed Light Curves, distances, H_o and q_o

Theoretical monochromatic light curves and photospheric expansion velocities are compared with observations of 27 Type Ia supernovae (SNe Ia). A set of 37 models has been considered which encompasses all currently discussed explosion scenarios for Type Ia supernovae including deflagrations, detonations, delayed detonations, pulsating delayed detonations and tamped detonations of Chandra- mass, and Helium detonations of low mass white dwarfs. The explosions are calculated using one-dimensional Lagrangian hydro and radiation-hydro codes with incorporated nuclear networks. Subsequently, light curves are constructed using our LC scheme which includes an implicit radiation transport, expansion opacities, a Monte-Carlo $\gamma$-ray transport, and molecular and dust formation. For some supernovae, results of detailed non-LTE calculations have been considered. Observational properties of our series of models are discussed, the relation between the absolute brightness, post-maximum decline rates, the colors at several moments of time, etc. All models with a Ni production larger than 0.4 solar masses produce light curves of similar brightness. The influence of the cosmological red shift on the light curves and on the correction for interstellar reddening is discussed. Based on data rectification of the standard deviation, a quantitative procedure to fit the observations has been used to the determine the free parameters, i.e. the correct model, the distance, the reddening, and the time of the explosion. The results are discussed in detail and applied to determine Ho and qo.Comment: 55 pages, 26 figures. For a postscript version with high resolution send E-Mail to [email protected]; To appear in "The Astrophysical Journal