49,736 research outputs found
The Stable Core and Dynamic Periphery in Top Management Teams
This study explores how top management teams make strategic decisions. The findings indicate that the top management team performs a variety of monitoring and control functions within most firms, but that a single team with stable composition does not make strategic choices in most organizations. Instead, different groups, with members from multiple organizational levels, form to make various strategic decisions. A stable subset of the top team forms the core of each of these multiple decision‐making bodies. The findings offer a possible explanation for inconsistent findings in the top management team literature, and suggest several new directions for future senior team research
Gravitational entropy of cosmic expansion
We apply a recent proposal to define "gravitational entropy" to the expansion
of cosmic voids within the framework of non-perturbative General Relativity. By
considering CDM void configurations compatible with basic observational
constraints, we show that this entropy grows from post-inflationary conditions
towards a final asymptotic value in a late time fully non-linear regime
described by the Lemaitre-Tolman-Bondi (LTB) dust models. A qualitatively
analogous behavior occurs if we assume a positive cosmological constant
consistent with a -CDM background model. However, the term
introduces a significant suppression of entropy growth with the terminal
equilibrium value reached at a much faster rate.Comment: 5 Pages, 2 figures, AN style. Contribution to Proceedings of the
Second Caribbean Symposium on Nuclear and Astroparticle Physics (STARS 2013),
La Habana, Cuba, 5-9 May 201
Why Catastrophic Organizational Failures Happen
Excerpt from the introduction:
The purpose of this chapter is to examine the major streams of research about catastrophic failures, describing what we have learned about why these failures occur as well as how they can be prevented. The chapter begins by describing the most prominent sociological school of thought with regard to catastrophic failures, namely normal accident theory. That body of thought examines the structure of organizational systems that are most susceptible to catastrophic failures. Then, we turn to several behavioral perspectives on catastrophic failures, assessing a stream of research that has attempted to understand the cognitive, group and organizational processes that develop and unfold over time, leading ultimately to a catastrophic failure. For an understanding of how to prevent such failures, we then assess the literature on high reliability organizations (HRO). These scholars have examined why some complex organizations operating in extremely hazardous conditions manage to remain nearly error free. The chapter closes by assessing how scholars are trying to extend the HRO literature to develop more extensive prescriptions for managers trying to avoid catastrophic failures
Quasi-local variables and scalar averaging in LTB dust models
We introduce quasi--local (QL) scalar variables in spherically symmetric LTB
models. If the QL scalars are defined as functionals, they become weighed
averages that generalize the standard proper volume averages on space slices
orthogonal to the 4-velocity. We examine the connection between QL functions
and functionals and the "back-reaction" term in the context of Buchert's
scalar averaging formalism. With the help of the QL scalars we provide rigorous
proof that back--reaction is positive for (i) all LTB models with negative and
asymptotically negative spatial curvature, and (ii) models with positive
curvature decaying to zero asymptotically in the radial direction. We show by
means of qualitative, but robust, arguments that generic LTB models exist,
either with clump or void profiles, for which an "effective" acceleration
associated with Buchert's formalism can mimic the effects of dark energy.Comment: Submitted contribution for the proceedings of the "Invisible Universe
Internationale Confernce", Palais de L'UNESCO, Paris, France, June 29-July 3,
2009. Jean-Michel ALIMI, editor. 10 pages, 2 figures. AIP macros: layoutstyle
8x11singl
Cosmic rays of leptons from Pulsars and Supernova Remnants
The latest results from PAMELA and FERMI experiments confirm the necessity to
improve theoretical models of production and propagation of galactic electrons
and positrons. There are many possible explanations for the positron excess
observed at energies larger than 10 GeV and for some features around 1 TeV in
the total flux of electrons and positrons. Supernovae are astrophysical objects
with the potential to explain these observations. In this work, we present an
updated study of the astrophysical sources of lepton cosmic rays and the
possible and the possible explanation of the anomalies in terms of
astrophysical sources.Comment: 6 pages, 1 figures, Proceeding for the Conference on Cosmic Rays for
Particle and Astroparticle Physics, CRICATPP 2010, Como, Ital
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