Curvature in Noncommutative Geometry

Our understanding of the notion of curvature in a noncommutative setting has progressed substantially in the past ten years. This new episode in noncommutative geometry started when a Gauss-Bonnet theorem was proved by Connes and Tretkoff for a curved noncommutative two torus. Ideas from spectral geometry and heat kernel asymptotic expansions suggest a general way of defining local curvature invariants for noncommutative Riemannian type spaces where the metric structure is encoded by a Dirac type operator. To carry explicit computations however one needs quite intriguing new ideas. We give an account of the most recent developments on the notion of curvature in noncommutative geometry in this paper.Comment: 76 pages, 8 figures, final version, one section on open problems added, and references expanded. Appears in "Advances in Noncommutative Geometry - on the occasion of Alain Connes' 70th birthday

Bell Polynomials and Brownian Bridge in Spectral Gravity Models on Multifractal Robertson–Walker Cosmologies

We obtain an explicit formula for the full expansion of the spectral action on Robertson–Walker spacetimes, expressed in terms of Bell polynomials, using Brownian bridge integrals and the Feynman–Kac formula. We then apply this result to the case of multifractal Packed Swiss Cheese Cosmology models obtained from an arrangement of Robertson–Walker spacetimes along an Apollonian sphere packing. Using Mellin transforms, we show that the asymptotic expansion of the spectral action contains the same terms as in the case of a single Robertson–Walkerspacetime, but with zeta-regularized coefficients, given by values at integers of the zeta function of the fractal string of the radii of the sphere packing, as well as additional log-periodic correction terms arising fromthe poles (off the real line) of this zeta function

Effects of Zataria Multi-Flora, Shirazi thyme, on the Severity of Premenstrual Syndrome

Background: Premenstrual Syndrome (PMS) is a common problem in women. Zataria multiflora Boiss is a valuable plant. This herbal plant has been used in different conditions. Objectives: The study was performed to investigate the effects of Zataria multiflora Boiss to control PMS symptoms. Materials and Methods: This study was a double-blinded, prospective randomized trial. The study population was the college students living in the dormitories of Isfahan University. Eighty-eight eligible students were randomly divided to intervention and control groups. Students completed the prospective record of the impact and severity of menstrual symptoms (PRISM) calendar including 30 PMS symptoms for four menstrual cycles (two cycles before, and two after the intervention). The intervention group received pearls containing 20 mg of Zataria multi-flora essence (four pearls each day) for two menstrual cycles, seven days before menstruation. The mean difference of PMS severity score between groups was analyzed with Mann-Whitney U test. The difference in frequency score of symptoms was analyzed using repeated-measure analysis of variance. Results: Thirty-eight students in intervention and 37 students in placebo group completed the study. The groups had no significant difference regarding the severity of PMS. Both groups showed a significant improvement in PMS severity score after the intervention. The repeated-measure analysis of variance showed that the frequency of symptoms decreased significantly in the cycles, but it was not different in intervention and placebo groups. Conclusions: Our findings did not support the use of Zataria multiflora Boiss in premenstrual syndrome

An effective modification of the homotopy perturbation method for MHD viscous flow over a stretching sheet

AbstractIn this paper, we propose a powerful modification of the homotopy perturbation method that will accelerate the rapid convergence of series solution. The modified method is employed to solve the MHD boundary-layer equations. The viscous fluid is electrically conducting in the presence of a uniform applied magnetic field and the induced magnetic field is neglected for small magnetic Reynolds number. Similarity solutions of ordinary differential equation resulting from the momentum equation are obtained. Finally, some numerical comparisons among the new modified homotopy perturbation method, the standard homotopy perturbation, the Exact Solution and the Shooting method have been made, which manifest that the modified method is a very accurate and effective algorithm to solve the two-dimensional MHD viscous flow over a stretching sheet

Spread of efflux pump overexpressing-mediated fluoroquinolone resistance and multidrug resistance in Pseudomonas aeruginosa by using an efflux pump inhibitor

Background: Fluoroquinolone resistance in Pseudomonas aeruginosa may be due to efflux pump overexpression and/or target mutations. We designed this study to investigate the efflux pump mediated fluoroquinolone resistance and check the increasing effectiveness of fluoroquinolones in combination with an efflux pumps inhibitor among P. aeruginosa isolates from burn wounds infections. Materials and Methods: A total of 154 consecutive strains of P. aeruginosa were recovered from separate patients hospitalized in a burn hospital, Tehran, Iran. The isolates first were studied by disk diffusion antibiogram for 11 antibiotics and then minimum inhibitory concentration (MIC) experiments were performed to detect synergy between ciprofloxacin and the efflux pump inhibitor, carbonyl cyanide-m-chlorophenyl hydrazone (CCCP). Then to elucidate the inducing of multi drug resistance due to different efflux pumps activation in Fluoroquinolone resistant isolates, synergy experiments were also performed in random ciprofloxacin resistant isolates which have overexpressed efflux pumps phenotypically, using CCCP and selected antibiotics as markers for Beta-lactams and Aminoglycosides. The isolates were also tested by polymerase chain reaction (PCR) for the presence of the MexA, MexC and MexE, which encode the efflux pumps MexAB-OprM, MexCD-OprJ and MexEF-OprN. Results: Most of the isolates were resistant to 3 or more antibiotics tested. More than half of the ciprofloxacin resistant isolates exhibited synergy between ciprofloxacin and CCCP, indicating the efflux pump activity contributed to the ciprofloxacin resistance. Also increased susceptibility of random ciprofloxacin resistant isolates of P. aeruginosa to other selected antibiotics, in presence of CCCP, implied multidrug extrusion by different active efflux pump in fluoroquinolones resistant strains. All of Ciprofloxacin resistant isolates were positive for MexA, MexC and MexE genes simultaneously. Conclusion: In this burn hospital, where multidrug resistant P. aeruginosa isolates were prevalent, ciprofloxacin resistance and multidrug resistance due to the overexpression of fluoroquinolones mediated efflux pumps has also now emerged. Early recognition of this resistance mechanism should allow the use of alternative antibiotics and use an efflux pumps inhibitor in combination with antibiotic therapy. © 2015 by The Korean Society of Infectious Diseases

Lead and Cadmium Concentrations in Throughfall of Pinus eldarica and Cupressus arizonica Plantations in a Semi-Arid Polluted Area

This research was carried out in order to quantify throughfall (TF) and interception loss (I) and to compare the chemical composition of TF, i.e. lead (Pb) and cadmium (Cd) as well as electrical conductivity (EC) and pH beneath Pinus eldarica and Cupressus arizonica plantations and the open field rainfall. The research was accomplished in the Chitgar Forest Park, a semi-arid polluted urban area, around Tehran, Iran. Gross rainfall (GR) was measured using ten collectors located in an open field. TF was quantified by randomly manual TF collectors placed beneath each plantation. Measurements were recorded on an event basis from 15 April 2010 to 15 February 2011. During the measurement, eighteen rainfall events with cumulative GR value of 114.8 mm were recorded. Interception loss was 35.3 mm by P. eldarica plantation and 30.4 mm by C. arizonica. There were strong correlations between I:GR and GR ((r2 Pinus = 0.686, r2 Cupressus = 0.766, p value ≤ 0.01). Pb and Cd concentrations as well as EC of TF were significantly different among P. eldarica and C. arizonica and the open field. The results demonstrated that interception represents a considerable portion of GR in P.eldarica and C. arizonica plantations and, therefore, it should be considered while choosing trees for plantations in semiarid climate zones of Iran. Our results showed that P.eldarica and C. arizonica plantations have good potentials for filtering the polluted air with Pb and Cd

Analysis and correction of noise on electronic circuits in an accelerator environment

Accelerator noise sources can cause both analog and digital electronic circuits to malfunction. This paper identifies and analyzes noise sources, and describes the methodology for measurement. Both general remedies and specific solutions to minimize the noise effects on accelerator electronic circuits are described. A policy for electronic design, board layout, assembly, and fabrication is established. Conclusions are drawn based on theoretical principles with practical examples shown in case studies

Protection and disinfection policies against SARS-CoV-2 (COVID-19)

In late December 2019, reports from China of the incidence of pneumonia with unknown etiology were sent to the World Health Organization (WHO). Shortly afterwards, the cause of this disease was identified as the novel beta-coronavirus, SARS-CoV-2, and its genetic sequence was published on January 12, 2020. Human-to-human transmission via respiratory droplets and contact with aerosol infected surfaces are the major ways of transmitting this virus. Here we attempted to collect information on virus stability in the air and on surfaces and ways of preventing of SARS-CoV-2 spreading

Spectral action for Bianchi type-IX cosmological models

In this paper we prove a rationality phenomena for the coefficients of the heat kernel expansion of the Dirac-Laplacian of Bianchi IX cosmological models. Due the complexities arising from the anisotropic nature of the model, we present a novel method of writing the heat coefficients as Wodzicki resiudes of certain Laplacians and then provide an elegant proof of the rationality result. That is, we show that each coefficient is described by a several variable polynomial with rational coefficients of the cosmic expansion factors and their higher derivatives of a certain order. This result confirms the arithmetic nature of the complicated terms in the expansion