129 research outputs found
An asteroseismic study of the O9V star HD 46202 from CoRoT space-based photometry
The O9V star HD 46202, which is a member of the young open cluster NGC 2244,
was observed by the CoRoT satellite in October/November 2008 during a short run
of 34 days. From the very high-precision light curve, we clearly detect beta
Cep-like pulsation frequencies with amplitudes of ~0.1 mmag and below. A
comparison with stellar models was performed using a chi^2 as a measure for the
goodness-of-fit between the observed and theoretically computed frequencies.
The physical parameters of our best-fitting models are compatible with the ones
deduced spectroscopically. A core overshooting parameter alpha_ov = 0.10 +-
0.05 pressure scale height is required. None of the observed frequencies are
theoretically excited with the input physics used in our study. More
theoretical work is thus needed to overcome this shortcoming in how we
understand the excitation mechanism of pulsation modes in such a massive star.
A similar excitation problem has also been encountered for certain pulsation
modes in beta Cep stars recently modelled asteroseismically.Comment: Accepted for publication in Astronomy and Astrophysics on 17/12/2010,
9 pages, 7 figures, 4 table
422 TREATMENT OF KNEE OA WITH ACETAMINOPHEN (3-4gr/day) DURING 12 MONTHS: A NATURALISTIC PROSPECTIVE STUDY
37 THE mtDNA HAPLOGROUP J MODULATES THE NITRIC OXIDE (NO) PRODUCTION AND TELOMERE LENGTH. ROLE IN OSTEOARTHRITIS (OA)
CoRoT observations of O stars: diverse origins of variability
Six O-type stars were observed continuously by the CoRoT satellite during a
34.3-day run. The unprecedented quality of the data allows us to detect even
low-amplitude stellar pulsations in some of these stars (HD 46202 and the
binaries HD 46149 and Plaskett's star). These cover both opacity-driven modes
and solar-like stochastic oscillations, both of importance to the
asteroseismological modelling of O stars. Additional effects can be seen in the
CoRoT light curves, such as binarity and rotational modulation. Some of the
hottest O-type stars (HD 46223, HD 46150 and HD 46966) are dominated by the
presence of red-noise: we speculate that this is related to a sub-surface
convection zone.Comment: 5 pages, 3 figures, conference paper. To be published in "Four
decades of Research on Massive Stars", Astronomical Society of the Pacific.
Eds. C. Robert, N. St-Louis and L. Drisse
Multi-wavelength observations of afterglow of GRB 080319B and the modeling constraints
We present observations of the afterglow of GRB 080319B at optical, mm and
radio frequencies from a few hours to 67 days after the burst. Present
observations along with other published multi-wavelength data have been used to
study the light-curves and spectral energy distributions of the burst
afterglow. The nature of this brightest cosmic explosion has been explored
based on the observed properties and it's comparison with the afterglow models.
Our results show that the observed features of the afterglow fits equally good
with the Inter Stellar Matter and the Stellar Wind density profiles of the
circum-burst medium. In case of both density profiles, location of the maximum
synchrotron frequency is below optical and the value of cooling break
frequency is below rays, s after the burst. Also, the
derived value of the Lorentz factor at the time of naked eye brightness is
with the corresponding blast wave size of cm. The
numerical fit to the multi-wavelength afterglow data constraints the values of
physical parameters and the emission mechanism of the burst.Comment: 8 Pages, 3 Figures, Accepted for publication to Astronomy and
Astrophysics on 02/04/200
The mtDNA haplogroups associate with different methylation patterns in articular chondrocytes
Avaliação sistêmica do setor industrial brasileiro: 1995-2009
Resumo O presente artigo busca avaliar o setor industrial sob uma ótica distinta da que tem sido utilizada quando se trata de industrialização/desindustrialização. O objetivo é analisar o caráter sistêmico do setor industrial a partir do método de insumo-produto, por meio de indicadores de intensidade direta e intensidade direta mais indireta da indústria. Por esta medida, é possível deixar mais clara a contribuição do artigo, ou seja, fornecer uma medida de integração produtiva do setor industrial com os demais setores, de modo a verificar se a indústria tem ganhado importância relativa como setor articulador das atividades produtivas
Acumulação de capital, poupança externa e desempenho macroeconômico dos países emergentes
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