34,135 research outputs found
The cosmological constant as an eigenvalue of the Hamiltonian constraint in Horava-Lifshits theory
In the framework of Horava-Lifshitz theory, we study the eigenvalues
associated with the Wheeler-DeWitt equation representing the vacuum expectation
values associated with the cosmological constant. The explicit calculation is
performed with the help of a variational procedure with trial wave functionals
of the Gaussian type. We analyze both the case with the detailed balanced
condition and the case without it. In the case without the detailed balance, we
find the existence of an eigenvalue depending on the set of coupling constants
(g2,g3) and (g4,g5,g6), respectively, and on the physical scale.Comment: RevTeX,11 Pages, Substantial Improvements. References added. To
appear in Phys.Rev.
Discontinuous Almost Automorphic Functions and Almost Automorphic Solutions of Differential Equations with Piecewise Constant Argument
In this article we introduce a class of discontinuous almost automorphic
functions which appears naturally in the study of almost automorphic solutions
of differential equations with piecewise constant argument. Their fundamental
properties are used to prove the almost automorphicity of bounded solutions of
a system of differential equations with piecewise constant argument. Due to the
strong discrete character of these equations, the existence of a unique
discrete almost automorphic solution of a non-autonomous almost automorphic
difference system is obtained, for which conditions of exponential dichotomy
and discrete Bi-almost automorphicity are fundamental
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Preliminary Results of Initial Testing for Coronavirus (COVID-19) in the Emergency Department
Introduction: On March 10, 2020, the World Health Organization declared a global pandemic due to widespread infection of the novel coronavirus 2019 (COVID-19). We report the preliminary results of a targeted program of COVID-19 infection testing in the ED in the first 10 days of its initiation at our institution.Methods: We conducted a review of prospectively collected data on all ED patients who had targeted testing for acute COVID-19 infection at two EDs during the initial 10 days of testing (March 10-19, 2020). During this initial period with limited resources, testing was targeted toward high-risk patients per Centers for Disease Control and Prevention guidelines. Data collected from patients who were tested included demographics, clinical characteristics, and test qualifying criteria. We present the data overall and by test results with descriptive statistics.Results: During the 10-day study period, the combined census of the study EDs was 2157 patient encounters. A total of 283 tests were ordered in the ED. The majority of patients were 18-64 years of age, male, non-Hispanic white, had an Emergency Severity Index score of three, did not have a fever, and were discharged from the ED. A total of 29 (10.2%) tested positive. Symptoms-based criteria most associated with COVID-19 were the most common criteria identified for testing (90.6%). All other criteria were reported in 5.51–43.0% of persons being tested. Having contact with a person under investigation was significantly more common in those who tested positive compared to those who tested negative (63% vs 24.5%, respectively). The majority of patients in both results groups had at least two qualifying criteria for testing (75.2%).Conclusion: In this review of prospectively collected data on all ED patients who had targeted testing for acute COVID-19 infection at two EDs in the first 10 days of testing, we found that 10.2% of those tested were identified as positive. The continued monitoring of testing and results will help providers understand how COVID-19 is progressing in the community
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