An institutional perspective on the diffusion of international management system standards : the case of the Environmental management standard ISO 14001.

This paper analyzes how national institutional factors affect the adoption of the intemational environmental management standard ISO 14001, using a panel of 139 countries from 1996 to 2006. The analysis emphasizes that during the emerging phase of the standard, the potentiallack of consensus within the constituents of the national institutional environment conceming the value of a new standard could send mixed signals to firrns about the standard. The resuIts show that in the early phase of adoption, regulative and norrnative forces within the institutional environment can work against each other. Results also show that regulative or coercive forces playa relatively more important role in the early phase of adoption of the standard than in the subsequent phases of diffusion. In the later phases of diffusion of ISO 14001, norrnative forces, such as the diffusion of other management standards, as well as factors related to trade, playa more important role. Because of the similarities between environmental management standards and corporate social responsibility standards, this study can help identify sorne of the challenges for diffusion of ISO management standards in the area of social responsibility.Environmental management standard; ISO 14001;

How many nucleosynthesis processes exist at low metallicity?

Abundances of low-metallicity stars offer a unique opportunity to understand the contribution and conditions of the different processes that synthesize heavy elements. Many old, metal-poor stars show a robust abundance pattern for elements heavier than Ba, and a less robust pattern between Sr and Ag. Here we probe if two nucleosynthesis processes are sufficient to explain the stellar abundances at low metallicity, and we carry out a site independent approach to separate the contribution from these two processes or components to the total observationally derived abundances. Our approach provides a method to determine the contribution of each process to the production of elements such as Sr, Zr, Ba, and Eu. We explore the observed star-to-star abundance scatter as a function of metallicity that each process leads to. Moreover, we use the deduced abundance pattern of one of the nucleosynthesis components to constrain the astrophysical conditions of neutrino-driven winds from core-collapse supernovae.Comment: 13 pages, published in Ap

Multiwavelength optical observations of chromospherically active binary systems V. FF UMa (2RE J0933+624): a system with orbital period variation

This is the fifth paper in a series aimed at studying the chromospheres of active binary systems using several optical spectroscopic indicators to obtain or improve orbital solution and fundamental stellar parameters. We present here the study of FF UMa (2RE J0933+624), a recently discovered, X-ray/EUV selected, active binary with strong H_alpha emission. The objectives of this work are, to find orbital solutions and define stellar parameters from precise radial velocities and carry out an extensive study of the optical indicators of chromospheric activity. We obtained high resolution echelle spectroscopic observations during five observing runs from 1998 to 2004. We found radial velocities by cross correlation with radial velocity standard stars to achieve the best orbital solution. We also measured rotational velocity by cross-correlation techniques and have studied the kinematic by galactic space- velocity components (U, V, W) and Eggen criteria. Finally, we have determined the chromospheric contribution in optical spectroscopic indicators, from Ca II H & K to Ca II IRT lines, using the spectral subtraction technique. We have found that this system presents an orbital period variation, higher than previously detected in other RS CVn systems. We determined an improved orbital solution, finding a circular orbit with a period of 3.274 days. We derived the stellar parameters, confirming the subgiant nature of the primary component and obtained rotational velocities (vsini), of 33.57 km/s and 32.38 km/s for the primary and secondary components respectively. From our kinematic study, we can deduce its membership to the Castor moving group. Finally, the activity study has given us a better understanding of the possible mechanisms that produce the orbital period variation.Comment: Latex file with 16 pages, 18 figures. Available at http://www.ucm.es/info/Astrof/invest/actividad/actividad_pub.html Accepted for publication in: Astronomy & Astrophysics (A&A

Rotational modulation of the photospheric and chromospheric activity in the young, single K2-dwarf PW And

High resolution echelle spectra of PW And (HD~1405) have been taken during eight observing runs from 1999 to 2002. The detailed analysis of the spectra allow us to determine its spectral type (K2V), mean heliocentric radial velocity (V_hel = -11.15 km/s) rotational velocity (vsin{i} = 22.6 km/s), and equivalent width of the lithium line 6707.8 AA (EW(LiI) = 273 mAA). The kinematic (Galactic Velocity (U, V, W)) confirms its membership of the Local Association moving group, in agreement with the age (30 to 80 Myrs) inferred from the color magnitude diagram and the lithium equivalent width. Photospheric activity (presence of cool spots that disturb the profiles of the photospheric lines) has been detected as changes in the the bisectors of the cross correlation function (CCF) resulting of cross-correlate the spectra of PW And with the spectrum of a non active star of similar spectral type. These variations of the CCF bisectors are related to the variations in the measured radial velocities and are modulated with a period similar to the photometric period of the star. At the same time, chromospheric activity has been analyzed, using the spectral subtraction technique and simultaneous spectroscopic observations of the H_alpha, H_beta, NaI D_1 and D_2$, HeI D_3, MgI b triplet, CaII H&K, and CaII infrared triplet lines. A flare was observed during the last observing run of 2001, showing an enhancement in the observed chromospheric lines. A less powerful flare was observed on 2002 August 23. The variations of the chromospheric activity indicators seem to be related to the photospheric activity. A correlation between radial velocity, changes in the CCF bisectors and equivalent width of different chromospheric lines is observed with a different behaviour between epochs 1999, 2001 and 2002.Comment: Latex file with 20 pages, 21 figures tar'ed gzip'ed. Full postscript (text, figures and tables) available at http://www.ucm.es/info/Astrof/users/dmg/pub_dmg.html Accepted for publication in: Astronomy & Astrophysics (A&A