32,652 research outputs found
A revised HRD for individual components of binary systems from BaSeL BVRI synthetic photometry. Influence of interstellar extinction and stellar rotation
Johnson BVRI photometric data for individual components of binary systems
have been provided by ten Brummelaar et al. (2000). This is essential because
such binaries could play a critical role in calibrating the single-star stellar
evolution theory. While they derived the effective temperature from their
estimated spectral type, we infer metallicity-dependent Teffs from a minimizing
method fitting the B-V, V-R and V-I colours. For this purpose, a grid of
621,600 flux distributions were computed from the Basel Stellar Library (BaSeL
2.2) of model-atmosphere spectra, and their theoretical colours compared with
the observed photometry. As a matter of fact, the BaSeL colours show a very
good agreement with the BVRI metallicity-dependent empirical calibrations of
Alonso et al. (1996), temperatures being different by 3+-3 % in the range
4000-8000 K for dwarf stars. Before deriving the metallicity-dependent Teff
from the BaSeL models, we paid particular attention to the influence of
reddening and stellar rotation. A comparison between the MExcess code and
neutral hydrogen column density data shows a good agreement for the sample but
we point out a few directions where the MExcess model overestimates the E(B-V)
colour excess. Influence of stellar rotation on the BVRI colours can be
neglected except for 5 stars with large vsini, the maximum effect on
temperature being less than 5%. Our final results are in good agreement with
previous spectroscopic determinations available for a few primary components,
and with ten Brummelaar et al. below ~10,000 K. Nevertheless, we obtain an
increasing disagreement with their Teffs beyond 10,000 K. Finally, we provide a
revised Hertzsprung-Russell diagram for the systems with the more accurately
determined temperatures. (Abridged)Comment: 11 pages, accepted for publication in A&
Ways to open innovation: main agents and sources in the Portuguese case
Facing increasing open innovation trends, Portuguese enterprises are considering the related processes and impacts. Thus, this work aims to identify the sectors whose enterprises most engage in open innovation (such as cooperation on this issue) and which sources/agents are most used. This is analyzed by sector and type of innovation as an interesting way of differentiation for better open innovation strategy delineation. Using the data from the Community Innovation Survey (CIS-2012), it first appraises the nature of the innovation process, either cooperative or firm-based, as the starting level of analysis. Then, it differentiates the results by sector illustrating which cooperation sources/agents are most used (scope) and relative intensity of use (scale). This is important to assess levels of openness and related factors. Results show that main innovating sectors in Portugal are of three types: research-based, knowledge-based and service-based. They reveal an increasing focus on knowledge and services, trends that have been leading to more active openness towards innovation. For instance, health and construction are increasing their openness for innovating and internationalizing processes. However, Portuguese innovation is still more firm-based (in-house) than cooperation-based, especially concerning new products' launching. This work and future analyzes around it can contribute to encourage the open innovation strategy in more sectors of the economy as an easy and effective way to cope with rapid trends and changes. (C) 2017 Elsevier Ltd. All rights reserved.info:eu-repo/semantics/publishedVersio
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