Choptuik scaling in six dimensions

We perform numerical simulations of the critical gravitational collapse of a spherically symmetric scalar field in 6 dimensions. The critical solution has discrete self-similarity. We find the critical exponent \gamma and the self-similarity period \Delta.Comment: 8 pages, 3 figures RevTe

Collapse of a Circular Loop of Cosmic String

We study the collapse of a circular loop of cosmic string. The gravitational field of the string is treated using the weak field approximation. The gravitational radiation from the loop is evaluated numerically. The memtric of the loop near the point of collapse is found analytically.Comment: 15 page

Barriers to guideline-concordant antibiotic use among inpatient physicians: A case vignette qualitative study

BACKGROUND: Greater adherence to antibiotic-prescribing guidelines may promote more judicious antibiotic use, which could benefit individual patients and society at large. OBJECTIVE: To assess physician knowledge and acceptance of antibiotic-prescribing guidelines through the use of case vignettes. DESIGN: We conducted semistructured interviews with 30 inpatient physicians. Participants were asked to respond to 3 hypothetical case vignettes: (1) a skin and soft tissue infection (SSTI), (2) suspected hospital-acquired pneumonia (HAP), and (3) asymptomatic bacteriuria (ASB). All participants received feedback according to guidelines from the Infectious Diseases Society of America (IDSA) and were asked to discuss their level of comfort with following these guidelines. SETTING: Two acute care teaching hospitals for adult patients. INTERVENTION: None. MEASUREMENTS: Data from transcribed interviews were analyzed using emergent thematic analysis. RESULTS: Participants were receptive to guidelines and believed they were useful. However, participants' responses to the case vignettes demonstrated that IDSA guideline recommendations were not routinely followed for SSTI, HAP, and ASB. We identified 3 barriers to guideline-concordant care: (1) physicians' lack of awareness of specific guideline recommendations; (2) tension between adhering to guidelines and the desire to individualize patient care; and (3) skepticism of certain guideline recommendations. CONCLUSIONS: Case vignettes may be useful tools to assess physician knowledge and acceptance of antibiotic-prescribing guidelines. Using case vignettes, we identified 3 barriers to following IDSA guidelines. Efforts to improve guideline-concordant antibiotic prescribing should focus on reducing such barriers at the local level

Scaling of curvature in sub-critical gravitational collapse

We perform numerical simulations of the gravitational collapse of a spherically symmetric scalar field. For those data that just barely do not form black holes we find the maximum curvature at the position of the central observer. We find a scaling relation between this maximum curvature and distance from the critical solution. The scaling relation is analogous to that found by Choptuik for black hole mass for those data that do collapse to form black holes. We also find a periodic wiggle in the scaling exponent.Comment: Revtex, 2 figures, Discussion modified, to appear in Phys. Rev.

Tensor mass and particle number peak at the same location in the scalar-tensor gravity boson star models - an analytical proof

Recently in boson star models in framework of Brans-Dicke theory, three possible definitions of mass have been identified, all identical in general relativity, but different in scalar-tensor theories of gravity.It has been conjectured that it's the tensor mass which peaks, as a function of the central density, at the same location where the particle number takes its maximum.This is a very important property which is crucial for stability analysis via catastrophe theory. This conjecture has received some numerical support. Here we give an analytical proof of the conjecture in framework of the generalized scalar-tensor theory of gravity, confirming in this way the numerical calculations.Comment: 9 pages, latex, no figers, some typos corrected, reference adde

Black holes and a scalar field in an expanding universe

We consider a model of an inhomogeneous universe including a massless scalar field, where the inhomogeneity is assumed to consist of many black holes. This model can be constructed by following Lindquist and Wheeler, which has already been investigated without including scalar field to show that an averaged scale factor coincides with that of the Friedmann model. In this work we construct the inhomogeneous universe with an massless scalar field, where we assume that the averaged scale factor and scalar field are given by those of the Friedmann model including a scalar field. All of our calculations are carried out in the framework of Brans-Dicke gravity. In constructing the model of an inhomogeneous universe, we define the mass of a black hole in the Brans-Dicke expanding universe which is equivalent to ADM mass if the mass evolves adiabatically, and obtain an equation relating our mass to the averaged scalar field and scale factor. As the results we find that the mass has an adiabatic time dependence in a sufficiently late stage of the expansion of the universe, and that the time dependence is qualitatively diffenrent according to the sign of the curvature of the universe: the mass increases decelerating in the closed universe case, is constant in the flat case and decreases decelerating in the open case. It is also noted that the mass in the Einstein frame depends on time. Our results that the mass has a time dependence should be retained even in the general scalar-tensor gravitiy with a scalar field potential. Furthermore, we discuss the relation of our results to the uniqueness theorem of black hole spacetime and gravitational memory effect.Comment: 16 pages, 3 tables, 5 figure

Inhomogeneity of Spatial Curvature for Inflation

We study how the initial inhomogeneities of the spatial curvature affect the onset of inflation in the closed universe. We consider a cosmological model which contains a radiation and a cosmological constant. In order to treat the inhomogeneities in the closed universe, we improve the long wavelength approximation such that the non-small spatial curvature is tractable in the lowest order. Using the improved scheme, we show how large inhomogeneities of the spatial curvature prevent the occurrence of inflation.Comment: 17 pages, revtex, 6 figures included using eps

The Budget Enforcement Act in 1992: Necessary But Not Sufficient

The 1992 budget process followed the Budget Enforcement Act of 1990 (BEA) script, although not without a protracted conflict concerning the walls separating the three categories of discretionary spending. The walls were retained, spending caps were met, and the process was timely. What deficit reduction occurred was the result of spending below the FY 1993 defense cap. Congress neither raised taxes nor cut entitlements to reduce the deficit further. The deficit grew significantly, driven by entitlement spending, chiefly health care programs. The limits of the BEA approach to spending control and deficit reduction became apparent

Long-wavelength approximation for string cosmology with barotropic perfect fluid

The field equations derived from the low energy string effective action with a matter tensor describing a perfect fluid with a barotropic equation of state are solved iteratively using the long-wavelength approximation, i.e. the field equations are expanded by the number of spatial gradients. In the zero order, a quasi-isotropic solution is presented and compared with the general solution of the pure dilaton gravity. Possible cosmological models are analyzed from the point of view of the pre-big bang scenario. The second order solutions are found and their growing and decaying parts are studied.Comment: 19 pages, 1 figur