39,473 research outputs found
A New Solution of The Cosmological Constant Problems
We extend the usual gravitational action principle by promoting the bare
cosmological constant (CC) from a parameter to a field which can take many
possible values. Variation leads to a new integral constraint equation which
determines the classical value of the effective CC that dominates the wave
function of the universe. In a realistic cosmological model, the expected value
of the effective CC, is calculated from measurable quantities to be O(t_U), as
observed, where t_U is the present age of the universe in Planck units,. Any
application of our model produces a falsifiable prediction for in
terms of other measurable quantities. This leads to a specific falsifiable
prediction for the observed spatial curvature parameter of Omega_k0=-0.0055.
Our testable proposal requires no fine tunings or extra dark-energy fields but
does suggest a new view of time and cosmological evolution.Comment: 5 pages; v3: version accepted by Phys. Rev. Let
A HETEROSKEDASTIC NESTED RUM OF FRESHWATER FISHING
Choice set definition can be viewed as a nesting issue. Although the behavioral basis for grouping sites into nests is not well understood, one reason for grouping alternatives into nests may be the likelihood that they are "in" or "out" of an individual's choice set. However, a problem with using nests to evaluate choice set issues is that the researcher typically needs to impose the same nesting structure on all individuals and trips. Such an approach assumes that the degree of correlation among the alternatives does not vary across the sample. This paper develops and tests a more flexible nesting structure that allows the parameters on the inclusive values to vary systematically based on the sample demographics.Resource /Energy Economics and Policy,
Strategic Buyers, Horizontal Mergers and Synergies: An Experimental Investigation*
This paper reports an experiment designed to evaluate interrelationships between strategic buyers, market power and merger-induced synergies. The experiment consists of 40 posted-offer quadropolies. Treatments include the use of simulated or human buyers, seller consolidations and merger-induced fixed cost and unit cost synergies. In the simulated-buyer markets we observe behavior generally consistent with comparative static predictions: prices rise post-merger, and unit (but not fixed) cost synergies may exert some price-moderating effect. The addition of powerful buyers changes results markedly. Although prices are lower in the human buyer markets, outcomes are more variable and predicted comparative static effects are no longer observed.
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