Modeling the line variations from the wind-wind shock emissions of WR 30a

The study of Wolf-Rayet stars plays an important role in evolutionary theories of massive stars. Among these objects, ~ 20% are known to be in binary systems and can therefore be used for the mass determination of these stars. Most of these systems are not spatially resolved and spectral lines can be used to constrain the orbital parameters. However, part of the emission may originate in the interaction zone between the stellar winds, modifying the line profiles and thus challenging us to use different models to interpret them. In this work, we analyzed the HeII4686\AA + CIV4658\AA blended lines of WR30a (WO4+O5) assuming that part of the emission originate in the wind-wind interaction zone. In fact, this line presents a quiescent base profile, attributed to the WO wind, and a superposed excess, which varies with the orbital phase along the 4.6 day period. Under these assumptions, we were able to fit the excess spectral line profile and central velocity for all phases, except for the longest wavelengths, where a spectral line with constant velocity seems to be present. The fit parameters provide the eccentricity and inclination of the binary orbit, from which it is possible to constrain the stellar masses.Comment: accepted for publication in the MNRA

Knowledge management in projects

Knowledge Transfer in Project-based Organizations has been recognized as productivity and economic growth promoters that are currently not properly managed. Therefore, it is critical to investigate the importance of knowledge regarding its acquisition, use and transfer across all departments of an organization. The main objective of this work was to evaluate how modern organizations from different business sectors manage and share their knowledge by following the Knowledge Management and Transfer Life-Cycles when developing their projects. Organizational surveys were performed to employees working in project management within Portuguese organizations (or with representation in Portugal,) from multiple business sectors and holding different hierarchical positions. The present study revealed that most Companies can identify, capture and retain the relevant knowledge, and apply it to the development of other projects. However, the steps corresponding to the transfer of knowledge between collaborators within the organization and to the evaluation/review of the benefit generated by the transferred knowledge are not being followed. The inexistence of a Project department or a team dedicated to projects within the organization seems to be limiting the effectiveness of knowledge management and transfer.info:eu-repo/semantics/acceptedVersio

Properties improvement of poly(o-methoxyaniline) based supercapacitors : experimental and theoretical behaviour study of self-doping effect

The support of this research by FAPESP (2011/10897-2, 2013/07296-2), CsF-PVE (99999.007708/2015-07), CAPES and CNPq is gratefully acknowledged. We also thank the University of Aberdeen for providing computational time on MaxwellPeer reviewedPostprin

The space-time torsion in the context of the Exact Foldy-Wouthuysen Transformation for a Dirac fermion

In this work we focus our attention in the inconsistency that appears when the Semi-Exact Foldy-Wouthuysen transformation for the Dirac field interacting with space-time torsion field is performed. In order to solve this problem, we present a new involution operator that makes possible to perform the exact transformation when torsion field is present. Such operator has a structure, well known in the literature, composed of the product of an operator that acts in the matrices space and another one that acts in the function space. We also present the bound state of this theory and discuss the possible experimental analysis

Public attitudes towards the restoration and management of Lake Vela (Central Portugal)

Lake Vela local inhabitants' and visitors' environmental attitudes and opinions about ecological conditions of the area and future management strategies to be implemented were investigated. The facilities required and the proposal to promote tourism activities, to enhance economic development, have revealed public illiteracy about ecosystems functioning and carrying capacity. This lack of scientific knowledge was recognized by a great percentage of individuals (61%, n=175), who mentioned environmental education programs as one of the main activities to be developed in the area. To spend some hours in a calm and healthy environment (67.6%, n=194), to share some moments with friends (58.2%, n=167), picnics (49.5, n=49.5%), and wildlife observation (46.7%, n=134) were the main motives cited by respondents to visit Lake Vela. These activities do not need to be restricted in the management of the area, but only directed for specific areas and carefully monitored, since they are passive activities that yield few significant impacts. The study also proposed some social benefits that could be integrated in the management of the area, in order to increase the quality of visitors' experiences and, hence, to get public compliance and involvement in the preservation of that natural resources

Global Alfven Wave Heating of the Magnetosphere of Young Stars

Excitation of a Global Alfven wave (GAW) is proposed as a viable mechanism to explain plasma heating in the magnetosphere of young stars. The wave and basic plasma parameters are compatible with the requirement that the dissipation length of GAWs be comparable to the distance between the shocked region at the star's surface and the truncation region in the accretion disk. A two-fluid magnetohydrodynamic plasma model is used in the analysis. A current carrying filament along magnetic field lines acts as a waveguide for the GAW. The current in the filament is driven by plasma waves along the magnetic field lines and/or by plasma crossing magnetic field lines in the truncated region of the disk of the accreting plasma. The conversion of a small fraction of the kinetic energy into GAW energy is sufficient to heat the plasma filament to observed temperatures.Comment: Submitted to ApJ, aheatf.tex, 2 figure