Evolution of zero-metallicity massive stars

We discuss the evolutionary properties of primordial massive and very massive stars, supposed to have formed from metal-free gas. Stellar models are presented over a large range of initial masses (8 Msun <= Mi <= 1000 Msun), covering the hydrogen- and helium-burning phases up to the onset of carbon burning. In most cases the evolution is followed at constant mass. To estimate the possible effect of mass loss via stellar winds, recent analytic formalisms for the mass-loss rates are applied to the very massive models (Mi >= 120 Msun).Comment: Invited talk at IAU Symp. 212, ``A Massive Star Odyssey, from Main Sequence to Supernova'', K.A. van der Hucht, A. Herrero, C. Esteban (eds.), 7 pages, 5 postscript figure

Sidra: alternativa para a diversificação e agregação de valor na cadeia produtiva da maçã no Brasil.

O objetivo do presente comunicado é fornecer informações básicas necessárias para o aprimoramento da qualidade da sidra elaborada no Brasil, a qual pode apresentar-se como alternativa de diversificação e agregação de valor na cadeia produtiva da maçã.bitstream/item/48542/1/ComunicadoTecnico-107.pd

Análise do perfil proteico durante a evolução da maturação em maçãs cv. Gala.

Este trabalho teve por objetivo identificar proteínas diferentemente expressas e que sejam diretamente associadas ao processo de amadurecimento

Liquid polymorphism and density anomaly in a three-dimensional associating lattice gas

We investigate the phase diagram of a three-dimensional associating gas $(ALG)$ model. This model combines orientational ice-like interactions and ``van der Waals'' that might be repulsive, representing, in this case, a penalty for distortion of hydrogen bonds. These interactions can be interpreted as two competing distances making the connection between this model and continuous isotropic soft-core potentials. We present Monte Carlo studies of the $ALG$ model showing the presence of two liquid phase, two critical points and A density anomaly

Teaching teamwork skills in Australian higher education business disciplines

Australian employers continue to indicate that the development of teamwork skills in graduates is as important as mastering technical skills required for a particular career. In Australia, the reporting on the teaching of teamwork skills has emanated across a range of disciplines including health and engineering, with less of a focus on business related disciplines. Although Australian university business schools appear to value the importance and relevance of developing teamwork skills, implementation of the teaching, learning and assessment of teamwork skills remains somewhat of a pedagogical conundrum. The aim of this paper is to present a systematic literature review so as to better understand the salient issues associated with teaching teamwork skills in Australian higher education business disciplines

On the peculiar red clump morphology in the open clusters NGC 752 and NGC 7789

The red clump stars in the open cluster NGC 752 present a peculiar distribution in the colour-magnitude diagran (CMD): the clump is observed to present a faint extension, slightly to the blue of the main concentration of clump stars. We point out that a similar structure is present in the CMD of NGC 7789, and discuss their possible origins. This feature may be understood as the result of having, at the same time, stars of low-mass which undergo the helium-flash, and those just massive enough for avoiding it. The ages of both clusters are compatible with this interpretation. Similar features can be produced in theoretical models which assume a non-negligible mass spread for clump stars, of about 0.2 Mo. However, one can probably exclude that the observed effect is due to the natural mass range of core helium burning stars found in single isochrones, although present models do not present the level of detail necessary to completely explore this possibility. Also the possibility of a large age spread among cluster stars can be refuted on observational grounds. We then suggest a few alternatives. This spread may be resulting either from star-to-star variations in the mass-loss rates during the RGB phase. Alternatively, effects sush as stellar rotation or convective core overshooting, could be causing a significant spread in the core mass at He-ignition for star of similar mass. Finally, we point out that similar effects could also help to understand the distribution of clump stars in the CMDs of the clusters NGC 2660 and NGC 2204

Uncertainties in stellar evolution models: convective overshoot

In spite of the great effort made in the last decades to improve our understanding of stellar evolution, significant uncertainties remain due to our poor knowledge of some complex physical processes that require an empirical calibration, such as the efficiency of the interior mixing related to convective overshoot. Here we review the impact of convective overshoot on the evolution of stars during the main Hydrogen and Helium burning phases.Comment: Proc. of the workshop "Asteroseismology of stellar populations in the Milky Way" (Sesto, 22-26 July 2013), Astrophysics and Space Science Proceedings, (eds. A. Miglio, L. Girardi, P. Eggenberger, J. Montalban