Double-slit interference pattern from single-slit screen and its gravitational analogues

The double slit experiment (DSE) is known as an important cornerstone in the foundations of physical theories such as Quantum Mechanics and Special Relativity. A large number of different variants of it were designed and performed over the years. We perform and discuss here a new verion with the somewhat unexpected results of obtaining interference pattern from single-slit screen. This outcome, which shows that the routes of the photons through the array were changed, leads one to discuss it, using the equivalence principle, in terms of geodesics mechanics. We show using either the Brill's version of the canonical formulation of general relativity or the linearized version of it that one may find corresponding and analogous situations in the framework of general relativity.Comment: 51 pages, 12 Figures five of them contain two subfigures and thus the number of figures is 17, 1 Table. Some minor changes introduced, especially, in the reference

Quantum Vacuum Instability Near Rotating Stars

We discuss the Starobinskii-Unruh process for the Kerr black hole. We show how this effect is related to the theory of squeezed states. We then consider a simple model for a highly relativistic rotating star and show that the Starobinskii-Unruh effect is absent.Comment: 17 Pages, (accepted by PRD), (previously incorrect header files have been corrected

Strings in Homogeneous Background Spacetimes

The string equations of motion for some homogeneous (Kantowski-Sachs, Bianchi I and Bianchi IX) background spacetimes are given, and solved explicitly in some simple cases. This is motivated by the recent developments in string cosmology, where it has been shown that, under certain circumstances, such spacetimes appear as string-vacua. Both tensile and null strings are considered. Generally, it is much simpler to solve for the null strings since then we deal with the null geodesic equations of General Relativity plus some additional constraints. We consider in detail an ansatz corresponding to circular strings, and we discuss the possibility of using an elliptic-shape string ansatz in the case of homogeneous (but anisotropic) backgrounds.Comment: 25 pages, REVTE

Analytical treatment of SUSY Quasi-normal modes in a non-rotating Schwarzschild black hole

We use the Fock-Ivanenko formalism to obtain the Dirac equation which describes the interaction of a massless 1/2-spin neutral fermion with a gravitational field around a Schwarzschild black hole (BH). We obtain approximated analytical solutions for the eigenvalues of the energy (quasi-normal frequencies) and their corresponding eigenstates (quasi-normal states). The interesting result is that all the excited states [and their supersymmetric (SUSY) partners] have a purely imaginary frequency, which can be expressed in terms of the Hawking temperature. Furthermore, as one expects for SUSY Hamiltonians, the isolated bottom state has a real null energy eigenvalue.Comment: Version to be published in European Physical Journal

Initial choice of oral glucose-lowering medication for diabetes mellitus: A patient-centered comparative effectiveness study

IMPORTANCE: Although many classes of oral glucose-lowering medications have been approved for use, little comparative effectiveness evidence exists to guide initial selection of therapy for diabetes mellitus. OBJECTIVE: To determine the effect of initial oral glucose-lowering agent class on subsequent need for treatment intensification and 4 short-term adverse clinical events. DESIGN, SETTING, AND PARTICIPANTS: This study was a retrospective cohort study of patients who were fully insured members of Aetna (a large national health insurer) who had been prescribed an oral glucose-lowering medication from July 1, 2009, through June 30, 2013. Individuals newly prescribed an oral glucose-lowering agent who filled a second prescription for a medication in the same class and with a dosage at or above theWorld Health Organization's defined daily dose within 90 days of the end-of-day's supply of the first prescription were studied. Individuals with interim prescriptions for other oral glucose-lowering medications were excluded. EXPOSURES; Initiation of treatment with metformin, a sulfonylurea, a thiazolidinedione, or a dipeptidyl peptidase 4 inhibitor. MAIN OUTCOMES AND MEASURES: Time to addition of a second oral agent or insulin, each component separately, hypoglycemia, other diabetes-related emergency department visits, and cardiovascular events. RESULTS A total of 15 516 patients met the inclusion criteria, of whom 8964 (57.8%) started therapy with metformin. In unadjusted analyses, use of medications other than metformin was significantly associated with an increased risk of adding a second oral agent only, insulin only, and a second agent or insulin (P < .001 for all). In propensity score and multivariable-adjusted Cox proportional hazards models, initiation of therapy with sulfonylureas (hazard ratio [HR], 1.68; 95%CI, 1.57-1.79), thiazolidinediones (HR, 1.61; 95%CI, 1.43-1.80), and dipeptidyl peptidase 4 inhibitors (HR, 1.62; 95%CI, 1.47-1.79) was associated with an increased hazard of intensification. Alternatives to metformin were not associated with a reduced risk of hypoglycemia, emergency department visits, or cardiovascular events. CONCLUSIONS AND RELEVANCE: Despite guidelines, only 57.8%of individuals began diabetes treatment with metformin. Beginning treatment with metformin was associated with reduced subsequent treatment intensification, without differences in rates of hypoglycemia or other adverse clinical events. These findings have significant implications for quality of life and medication costs

Charged AdS Black Holes and Catastrophic Holography

We compute the properties of a class of charged black holes in anti-de Sitter space-time, in diverse dimensions. These black holes are solutions of consistent Einstein-Maxwell truncations of gauged supergravities, which are shown to arise from the inclusion of rotation in the transverse space. We uncover rich thermodynamic phase structures for these systems, which display classic critical phenomena, including structures isomorphic to the van der Waals-Maxwell liquid-gas system. In that case, the phases are controlled by the universal `cusp' and `swallowtail' shapes familiar from catastrophe theory. All of the thermodynamics is consistent with field theory interpretations via holography, where the dual field theories can sometimes be found on the world volumes of coincident rotating branes.Comment: 19 pages, revtex, psfig, 6 multicomponent figures, typos, references and a few remarks have been repaired, and adde

Black hole solutions in F(R) gravity with conformal anomaly

In this paper, we consider $F(R)=R+f(R)$ theory instead of Einstein gravity with conformal anomaly and look for its analytical solutions. Depending on the free parameters, one may obtain both uncharged and charged solutions for some classes of $F(R)$ models. Calculation of Kretschmann scalar shows that there is a singularity located at $r=0$, which the geometry of uncharged (charged) solution is corresponding to the Schwarzschild (Reissner-Nordstr\"om) singularity. Further, we discuss the viability of our models in details. We show that these models can be stable depending on their parameters and in different epoches of the universe.Comment: 12 pages, one figur

Factors associated with syphilis seroprevalence in women with and at-risk for HIV infection in the Women's Interagency HIV Study (1994-2015)

Objective Syphilis rates among women in the USA more than doubled between 2014 and 2018. We sought to identify correlates of syphilis among women enrolled in the Women's Interagency HIV Study (WIHS) to inform targeted interventions. Methods The retrospective cross-sectional analysis of secondary data included women with HIV or at-risk of HIV who enrolled in the multisite US WIHS cohort between 1994 and 2015. Syphilis screening was performed at baseline. Infection was defined serologically by a positive rapid plasma reagin test with confirmatory treponemal antibodies. Sociodemographic and behavioural characteristics stratified by baseline syphilis status were compared for women enrolled during early (1994-2002) and recent (2011-2015) years. Multivariable binomial modelling with backward selection (p>0.2 for removal) was used to model correlates of syphilis. Results The study included 3692 women in the early cohort and 1182 women in the recent cohort. Syphilis prevalence at enrolment was 7.5% and 3.7% in each cohort, respectively (p100 lifetime sex partners (all p<0.05). In the recent cohort, age (adjusted prevalence OR (aPOR) 0.2, 95% CI 0.1 to 0.6 for 30-39 years; aPOR 0.5, 95% CI 0.2 to 1.0 for 40-49 years vs ≥50 years), hepatitis C seropositivity (aPOR 2.1, 95% CI 1.0 to 4.1) and problem alcohol use (aPOR 2.2, 95% CI 1.1 to 4.4) were associated with infection. Conclusions Syphilis screening is critical for women with HIV and at-risk of HIV. Targeted prevention efforts should focus on women with hepatitis C and problem alcohol use

Spinor model of a perfect fluid and their applications in Bianchi type-I and FRW models

Different characteristic of matter influencing the evolution of the Universe has been simulated by means of a nonlinear spinor field. Exploiting the spinor description of perfect fluid and dark energy evolution of the Universe given by an anisotropic Bianchi type-I (BI) or isotropic Friedmann-Robertson-Walker (FRW) one has been studied.Comment: 10 pages, 8 Figure