32,514 research outputs found
A reciprocal Wald theorem for varying gravitational function
We study when a cosmological constant is a natural issue if it is mimicked by
the potential of a massive Hyperextended Scalar Tensor theory with a perfect
fluid for Bianchi type I and V models. We then deduce a reciprocal Wald theorem
giving the conditions such that the potential tends to a non vanishing constant
when the gravitational function varies. We also get the conditions allowing the
potentiel to vanish or diverge.Comment: 13 page
The Foundation Performance Dashboard: Vital Statistics for Social Impact
Boards and foundation leadership rarely have a clear, consistent, and comprehensive picture of their foundation's performance. Interestingly, this situation persists despite the fact that nearly 60% of foundation CEOs would like to have more board involvement in reviewing the foundation's philanthropic mission and effectiveness. Our experience suggests that this conundrum results from a fundamental uncertainty: Foundations are unsure how to bridge the chasm between the readily available and concise metrics for investment performance and the much more complex, expensive, and subjective data from internal operations and program evaluations
Cybersocialism. Group Consciousness in Transnational Communities
An important new type of community is emerging with the rapid advances in communication technologies: communities that cross cultural and political boundaries to engage in a commerce of information exchange. While there has been much research focused on the technological development of computersupported collaborative work, less is known about sociocultural attitudes and an understanding of how people perceive “belongingness” to a community in an environment where interaction is mediated by shared computer resources
A coupled vacuum energy model producing endless alternated phases of accelerated and decelerated expansion
We consider a flat Universe filled with a vacuum energy coupled to matter and
radiation by respectively positive coupling functions and . We
require that these functions be such as Universe exits from inflation to go to
a radiation dominated epoch and allow to reproduce the observed
expansion after this last epoch. These requirements lead to some necessary
constraints on the coupling functions. We then look at one of the simplest
forms of and able to satisfy them. The cosmological model thus
defined describes a Universe with an initial singularity and endless alternated
periods of accelerated and decelerated expansion (one of them being our
Universe) unifying inflation and present time expansion
acceleration.Comment: 18 pages, 10 figur
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