Background Fields in 2+1 Topological Gravity

The partition function of 2+1 Chern-Simons Witten topological gravity has an attractive interpretation in terms of the unbroken and broken phases of gravity. We make this physical interpretation manifest using the background field method.Comment: 10 pages, LaTeX, OUTP-93-03

On the Physical Origin of the Oppenheimer-Ahluwalia Zero-Energy Solutions

In virtue of the Chubykalo - Smirnov-Rueda generalized form of the Maxwell-Lorentz equation a new form of the energy density of the electromagnetic field was obtained. This result allows us to explain a physical origin of the Oppenheimer-Ahluwalia zero-energy solutions of the Maxwell equations.Comment: Mod. Phys. Lett. style, 8pp., no figure

Comparison of Solar and Other Influences on Long-term Climate

Examples are shown of climate variability, and unforced climate fluctuations are discussed, as evidenced in both model simulations and observations. Then the author compares different global climate forcings, a comparison which by itself has significant implications. Finally, the author discusses a new climate simulation for the 1980s and 1990s which incorporates the principal known global climate forcings. The results indicate a likelihood of rapid global warming in the early 1990s

Generating the Baryon Asymmetry of the Universe in Split Fermion Models

The origin of the matter-antimatter asymmetry of the universe is one of the major unsolved problems in cosmology and particle physics. In this paper, we investigate the recently proposed possibility that split fermion models -- extra dimensional models where the standard model fermions are localized to different points around the extra dimension -- could provide a means to generate this asymmetry during the phase transition of the localizing scalars. After setting up the scenario that we consider, we use a single fermion toy model to estimate the reflection coefficients for scattering off the phase boundary using a more realistic scalar profile than previous work resulting in a different Kaluza Klein spectrum. The value we calculate for $n_B/s$ is consistent with the mechanism being the source of the baryon asymmetry of our universe provided the $B-L$ violating processes have an efficiency of order $10^{-5}$.Comment: 17 pages, 3 figures; References added; Minor changes, Accepted for publication in Phys. Rev.

Shooting the Auctioneer

Most dynamic stochastic general equilibrium models of the macroeconomy assume that labor is traded in a spot market. Two exceptions by David Andolfatto and Monika Merz combine a two-sided search model with a one-sector real business cycle model. These hybrid models are successful, in some dimensions, but they cannot account for observed volatility in unemployment and vacancies. Following suggestions by Robert Hall and Robert Shimer, this paper shows that a relatively standard DSGE model with sticky wages can account for these facts. Using a second-order approximation to the policy function we simulate moments of an artificial economy with and without sticky wages and we document the dependence of unemployment and vacancy volatility on two key parameters; the disutility of effort and the degree of wage stickiness. We compute the welfare costs of the sticky wage equilibrium and find them to be small.

Quantum Einstein Gravity as a Topological Field Theory

General covariance in quantum gravity is seen once one integrates over all possible metrics. In recent years topological field theories have given us a different route to general covariance without integrating over all possible metrics. Here we argue that Einstein quantum gravity may be viewed as a topological field theory provided a certain constrant from the path integral measure is satisfied.Comment: 10 pages, LaTe

Taking A Stand: The Effects Of Standing Desks On Task Performance And Engagement

Time spent sitting is associated with negative health outcomes, motivating some individuals to adopt standing desk workstations. This study represents the first investigation of the effects of standing desk use on reading comprehension and creativity. In a counterbalanced, within-subjects design, 96 participants completed reading comprehension and creativity tasks while both sitting and standing. Participants self-reported their mood during the tasks and also responded to measures of expended effort and task difficulty. In addition, participants indicated whether they expected that they would perform better on work-relevant tasks while sitting or standing. Despite participants’ beliefs that they would perform worse on most tasks while standing, body position did not affect reading comprehension or creativity performance, nor did it affect perceptions of effort or difficulty. Mood was also unaffected by position, with a few exceptions: Participants exhibited greater task engagement (i.e., interest, enthusiasm, and alertness) and less comfort while standing rather than sitting. In sum, performance and psychological experience as related to task completion were nearly entirely uninfluenced by acute (~30-min) standing desk use. View Full-Tex