One-loop quantum corrections to cosmological scalar field potentials

We study the loop corrections to potentials of complex or coupled real scalar fields used in cosmology to account for dark energy, dark matter or dark fluid. We show that the SUGRA quintessence and dark matter scalar field potentials are stable against the quantum fluctuations, and we propose solutions to the instability of the potentials of coupled quintessence and dark fluid scalar fields. We also find that a coupling to fermions is very restricted, unless this coupling has a structure which already exists in the scalar field potential or which can be compensated by higher order corrections. Finally, we study the influence of the curvature and kinetic term corrections.Comment: 11 pages, 1 figure, accepted for publication in Phys. Rev.

Predictors of sun-protective practices among Iranian female college students: Application of protection motivation theory

Purpose: Given the importance of sun protection in the prevention of skin cancer, this study was designed to determine predictors of sun-protective practices among a sample of Iranian female college students based on protection motivation theory (PMT) variables. Materials and Methods: In this cross-sectional study, a total of 201 female college students in Iran University of Medical Sciences were selected. Demographic and PMT variables were assessed with a 67-item questionnaire. Multiple linear regression was used to identify demographic and PMT variables that were associated with sun-protective practices and intention. Results: one percent of participants always wore a hat with a brim, 3.5 gloves and 15.9 sunglasses while outdoors. Only 10.9 regularly had their skin checked by a doctor. Perceived rewards, response efficacy, fear, self-efficacy and marital status were the five variables which could predict 39 variance of participants intention to perform sun-protective practices. Also, intention and response cost explained 31 of the variance of sun-protective practices. Conclusions: These predictive variables may be used to develop theory-based education interventions to prevent skin cancer among college students

The decay Bs -> mu+ mu-: updated SUSY constraints and prospects

We perform a study of the impact of the recently released limits on BR(Bs -> mu+ mu-) by LHCb and CMS on several SUSY models. We show that the obtained constraints can be superior to those which are derived from direct searches for SUSY particles in some scenarios, and the use of a double ratio of purely leptonic decays involving Bs -> mu+ mu- can further strengthen such constraints. We also discuss the experimental sensitivity and prospects for observation of Bs -> mu+ mu- during the sqrt(s)=7 TeV run of the LHC, and its potential implications.Comment: 30 pages, 21 figures. v2: Improved discussion of constraints from B -> tau nu, references adde

Constraints on charged Higgs bosons from D(s)+- -> mu+- nu and D(s)+- -> tau+- nu

The decays D(s)+- -> mu+- nu and D(s)+- -> tau+- nu have traditionally been used to measure the D(s)+- meson decay constant f_D(s). Recent measurements at CLEO-c and the B factories suggest a branching ratio for both decays somewhat higher than the Standard Model prediction using f_D(s) from unquenched lattice calculations. The charged Higgs boson (H+-) in the Two Higgs Doublet Model (Type II) would also mediate these decays, but any sizeable contribution from H+- can only suppress the branching ratios and consequently is now slightly disfavoured. It is shown that constraints on the parameters tan(beta) and m_H+- from such decays can be competitive with and complementary to analogous constraints derived from the leptonic meson decays B+- -> tau+- nu_tau and K+- -> mu+- nu_mu, especially if lattice calculations eventually prefer f_D(s) < 250 MeV.Comment: 18 pages, 4 figure

Measuring V_ub and probing SUSY with double ratios of purely leptonic decays of B and D mesons

The experimental prospects for precise measurements of the leptonic decays B_u -> tau nu / mu nu, B_s -> mu+ mu-, D -> mu nu and D_s -> mu nu / tau nu are very promising. Double ratios involving four of these decays can be defined in which the dependence on the values of the decay constants is essentially eliminated, thus enabling complementary measurements of the CKM matrix element V_ub with a small theoretical error. We quantify the experimental error in a possible future measurement of |V_ub| using this approach, and show that it is competitive with the anticipated precision from the conventional approaches. Moreover, it is shown that such double ratios can be more effective than the individual leptonic decays as a probe of the parameter space of supersymmetric models. We emphasize that the double ratios have the advantage of using |V_ub| as an input parameter (for which there is experimental information), while the individual decays have an uncertainty from the decay constants (e.g. f_B_s), and hence a reliance on theoretical techniques such as lattice QCD.Comment: 21 pages, 4 figure

Implications of LHC Searches on SUSY Particle Spectra: The pMSSM Parameter Space with Neutralino Dark Matter

We study the implications of LHC searches on SUSY particle spectra using flat scans of the 19-parameter pMSSM phase space. We apply constraints from flavour physics, g_mu-2, dark matter and earlier LEP and Tevatron searches. The sensitivity of the LHC SUSY searches with jets, leptons and missing energy is assessed by reproducing with fast simulation the recent CMS analyses after validation on benchmark points. We present results in terms of the fraction of pMSSM points compatible with all the constraints which are excluded by the LHC searches with 1 fb^{-1} and 15 fb^{-1} as a function of the mass of strongly and weakly interacting SUSY particles. We also discuss the suppression of Higgs production cross sections for the MSSM points not excluded and contrast the region of parameter space tested by the LHC data with the constraints from dark matter direct detection experiments.Comment: 14 pages, 13 figures. v2: increased statistics, to appear in EPJ

Isolation and typing of the influenza viruses in the Caspian littoral of Iran

Present study introduces results of common influenza virus strains in the north of Iran. Samples collected from 65 patients with acute respiratory illness by throat washing and swabs, randomly from north of Iran (Mazandaran, Golestan and Guilan provinces). The patients suffered from fever (high), cough, sore throat, general malaise, chill and myalgia. Viruses were isolated by cell culture and confirmed with HA (Hemagglutination) test and then typed by and HI (Hemagglutination Inhibition) test. Out of 65 throat samples, 12 influenza viruses were isolated and typed. Isolated viruses belonged to A (H1N1), A (H3N2) and B influenza viruses. This study showed that Influenza viruses displayed identical pattern to other provinces in Iran and to other countries. To fight against epidemics and pandemics, we should collect enough data about status of influenza each year and data of exact vaccine formulation application for use in different areas of the world. Acquired data has shown that the vaccine for above viruses that confirmed by WHO can result in decreased risks of influenza in at risk cases in provinces of north Iran

Covers of acts over monoids II

In 1981 Edgar Enochs conjectured that every module has a flat cover and finally proved this in 2001. Since then a great deal of effort has been spent on studying different types of covers, for example injective and torsion free covers. In 2008, Mahmoudi and Renshaw initiated the study of flat covers of acts over monoids but their definition of cover was slightly different from that of Enochs. Recently, Bailey and Renshaw produced some preliminary results on the `other' type of cover and it is this work that is extended in this paper. We consider free, divisible, torsion free and injective covers and demonstrate that in some cases the results are quite different from the module case

Supersymmetric constraints from Bs -> mu+mu- and B -> K* mu+mu- observables

We study the implications of the recent LHCb limit and results on Bs -> mu+mu- and B -> K* mu+mu- observables in the constrained SUSY scenarios. After discussing the Standard Model predictions and carefully estimating the theoretical errors, we show the constraining power of these observables in CMSSM and NUHM. The latest limit on BR(Bs -> mu+mu-), being very close to the SM prediction, constrains strongly the large tan(beta) regime and we show that the various angular observables from B -> K* mu+mu- decay can provide complementary information in particular for moderate tan(beta) values.Comment: 30 pages, 14 figure

Determining Overall Survival and Risk Factors in Esophageal Cancer Using Censored Quantile Regression

BACKGROUND: Esophageal cancer is one of the leading causes of death worldwide. The global increasing rate of this type of cancer requires more attention. The purpose of this study was to determine the overall survival probability of esophageal cancer after diagnosis and to assess the potential risk factors in a population of Iranian patients. MATERIALS AND METHODS: This retrospective cohort study was conducted on 127 cases with esophageal cancer in the Azarbaijan province, East of Iran. Participants in the study were diagnosed during 2009-2010 and were followed up for 5 years. The event was considered death due to esophageal cancer and those who survived until the end of the study were assumed as right censored. Censored quntile regression was fitted to find the overall survival of the patients using adjusted effects of variables and was compared with Cox regression model. RESULTS: Patients’ mean and median survival time were 16.99 and 10.06 months respectively and 89% off cases died by the end of the study. The 1, 3, 6, 12 and 36-month survival probabilities were 0.95, 0.76, 0.60, 0.43, and 0.18. The median survival time for females and males without surgery were 21.79 and 14.76 month respectively. The accuracy of predictions were 0.99 and 0.74 for the censored quantile regression and Cox, respectively. CONCLUSION: We concluded that being male, not having surgery, longer wait time between having symptoms and being diagnosed, low socioeconomic status and old age to be significant risk factors in reducing the probability of survival from esophageal cancer