Nucleosynthesis from massive stars 50 years after B2FH

We review some important observed properties of massive stars. Then we discuss how mass loss and rotation affect their evolution and help in giving better fits to observational constraints. Consequences for nucleosynthesis at different metallicities are discussed. Mass loss appear to be the key feature at high metallicity, while rotation is likely dominant at low and very low metallicities. We discuss various indications supporting the view that very metal poor stars had their evolution strongly affected by rotational mixing. Many features, like the origin of primary nitrogen at low metallicity, that of the C-rich extremely metal poor halo stars, of He-rich stars in massive globular clusters, of the O-Na anticorrelation in globular clusters may be related to the existence of a population of very fast rotating metal poor stars that we tentatively call the {\it spinstars}. A fraction of these {\it spinstars} may also be the progenitors of GRB in very metal poor regions. They may avoid pair instability explosion due to the heavy mass loss undergone during their early evolutionary phases and be, dependent on their frequency, important sources of ionising photons in the early Universe.Comment: 46 pages, 17 figures, in Stellar Nucleosynthesis: 50 years after B2FH, C. Charbonnel and J.P. Zahn (Eds.), EAS publications Serie

A Human Proteome Detection and Quantitation Project*

The lack of sensitive, specific, multiplexable assays for most human proteins is the major technical barrier impeding development of candidate biomarkers into clinically useful tests. Recent progress in mass spectrometry-based assays for proteotypic peptides, particularly those with specific affinity peptide enrichment, offers a systematic and economical path to comprehensive quantitative coverage of the human proteome. A complete suite of assays, e.g. two peptides from the protein product of each of the ∼20,500 human genes (here termed the human Proteome Detection and Quantitation project), would enable rapid and systematic verification of candidate biomarkers and lay a quantitative foundation for subsequent efforts to define the larger universe of splice variants, post-translational modifications, protein-protein interactions, and tissue localization

Radiative hydrodynamics simulations of red supergiant stars. IV. Gray versus non-gray opacities

Context. Red supergiants are massive evolved stars that contribute extensively to the chemical enrichment of our Galaxy. It has been shown that convection in those stars produces large granules that cause surface inhomogeneities and shock waves in the photosphere. The understanding of their dynamics is crucial for unveiling the unknown mass-loss mechanism, their chemical composition, and their stellar parameters. Aims. We present a new generation of red supergiant simulations with a more sophisticated opacity treatment performed with 3D radiative-hydrodynamics code CO5BOLD. Methods. In the code the coupled equations of compressible hydrodynamics and non-local radiation transport are solved in the presence of a spherical potential. The stellar core is replaced by a special spherical inner boundary condition, where the gravitational potential is smoothed and the energy production by fusion is mimicked by a simply producing heat corresponding to the stellar luminosity. All outer boundaries are transmitting for matter and light. The post-processing radiative transfer code OPTIM3D is used to extract spectroscopic and interferometric observables. Results. We show that if one relaxes the assumption of frequency-independent opacities, this leads to a steeper mean thermal gradient in the optical thin region that strongly affects the atomic strengths and the spectral energy distribution. Moreover, the weaker temperature fluctuations reduce the incertitude on the radius determination with interferometry. We show that 1D models of red supergiants must include a turbulent velocity that is calibrated on 3D simulations to obtain the effective surface gravity that mimics the effect of turbulent pressure on the stellar atmosphere. We provide an empirical calibration of the ad hoc micro- and macroturbulence parameters for 1D models using the 3D simulations: we find that there is no clear distinction between the different macroturbulent profiles needed in 1D models to fit 3D synthetic lines. © ESO, 2011.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Oncogenic Braf Induces Melanocyte Senescence and Melanoma in Mice

SummaryWe show here that inducible expression of BrafV600E off the endogenous Braf gene in mouse melanocytes stimulates skin hyperpigmentation and the appearance of nevi harboring senescent melanocytes. Additionally, approximately 70% of BrafV600E mice develop melanomas that reproduce many of the cardinal histological and molecular features of human melanoma and whose cells can colonize the lungs of nude mice. We show that the tumor suppressor p16INK4a is not required to induce melanocyte senescence and that its loss is not required for tumor progression, although it does regulate tumor penetrance and latency. Thus, we have developed a mouse model of melanoma driven by BrafV600E expressed at physiological levels that reflects the genetics and pathology of the human disease