1,700 research outputs found

    Gauged M-flation After BICEP2

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    In view of the recent BICEP2 results [arXiv:1403.3985] which may be attributed to the observation of B-modes polarization of the CMB with tensor-to-scalar ratio r=0.20.05+0.07r=0.2_{-0.05}^{+0.07}, we revisit M-flation model. Gauged M-flation is a string theory motivated inflation model with Matrix valued scalar inflaton fields in the adjoint representation of a U(N)U(N) Yang-Mills theory. In continuation of our previous works, we show that in the M-flation model induced from a supersymmetric 10d background probed by a stack of NN D3-branes, the "effective inflaton" ϕ\phi has a double-well Higgs-like potential, with minima at ϕ=0,μ\phi=0,\mu. We focus on the ϕ>μ\phi>\mu, symmetry-breaking region. We thoroughly examine predictions of the model for rr in the 2σ2\sigma region allowed for nSn_S by the Planck experiment. As computed in [arXiv:0903.1481], for Ne=60N_e=60 and nS=0.96n_S=0.96 we find r0.2r\simeq 0.2, which sits in the sweet spot of BICEP2 region for rr. We find that with increasing μ\mu arbitrarily, nSn_S cannot go beyond 0.9670\simeq 0.9670. As nSn_S varies in the 2σ2\sigma range which is allowed by Planck and could be reached by the model, rr varies in the range [0.1322,0.2623][0.1322,0.2623]. Future cosmological experiments, like the CMBPOL, that confines nSn_S with σ(nS)=0.0029\sigma(n_S)=0.0029 can constrain the model further. Also, in this region of potential, for nS=0.9603n_S=0.9603, we find that the largest isocurvature mode, which is uncorrelated with curvature perturbations, has a power spectrum with the amplitude of order 101110^{-11} at the end of inflation. We also discuss the range of predictions of rr in the hilltop region, ϕ<μ\phi< \mu.Comment: v1:16 pages, 9 figures; v2: matched the published versio

    A Class of Distal Functions on Semitopological Semigroups

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    The norm closure of the algebra generated by the set {nλnk:\{n\mapsto {\lambda}^{n^k}: λT\lambda\in{\mathbb {T}} and kN}k\in{\mathbb{N}}\} of functions on (Z,+)({\mathbb {Z}}, +) was studied in \cite{S} (and was named as the Weyl algebra). In this paper, by a fruitful result of Namioka, this algebra is generalized for a general semitopological semigroup and, among other things, it is shown that the elements of the involved algebra are distal. In particular, we examine this algebra for (Z,+)({\mathbb {Z}}, +) and (more generally) for the discrete (additive) group of any countable ring. Finally, our results are treated for a bicyclic semigroup.Comment: To appear in Methods Funct. Anal. Topolog

    Boundary Conditions as Dirac Constraints

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    In this article we show that boundary conditions can be treated as Lagrangian and Hamiltonian constraints. Using the Dirac method, we find that boundary conditions are equivalent to an infinite chain of second class constraints which is a new feature in the context of constrained systems. Constructing the Dirac brackets and the reduced phase space structure for different boundary conditions, we show why mode expanding and then quantizing a field theory with boundary conditions is the proper way. We also show that in a quantized field theory subjected to the mixed boundary conditions, the field components are noncommutative.Comment: 18 pp, Latex, minor changes, typos correcte

    Silica and esophageal cancer in Golestan province northeast of Iran

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    Objectives: Association of silica with diseases like cancers has been determined previously. This study was designed to determine the quantity of silis in flour produced in Golestan province and its relation to the esophageal cancer. Methodology: We took flour samples from all flour mills in Golestan province. Base-melting method in nickel cruise was used in 550° c; the extract was reduced with acid. The differences between silis concentration in various regions were compared. P-value 0.05). Conclusions: This study did not show high level of silica in the flour of Golestan province. We could not find significant differences between silica contaminations in the various areas. Further studies on the consumed bread and rice in the various regions of the province can be helpful

    Hepatitis C in hemodialysis centers of golestan province, northeast of Iran (2005)

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    Background and Aims: Nosocomial transmission of blood-borne pathogens is common in a dialysis setting. Hepatitis C virus (HCV) infection is a common problem that increases morbidity and mortality in hemodialysis patients. Blood transfusion and the duration of hemodialysis are the most important factors in HCV transmission. The aim of the study was to determine the incidence rate of HCV antibody in hemodialysis patients and its association with some factors. Methods: In this descriptive-analytical study, HCV antibody was measured in 93 hemodialysis patients in all hospitals affiliated to Golestan University of Medical Sciences. Standard infection prevention measures in hospital settings and dialysis units were performed including serologic testing for HCV antibody for every new patient in the dialysis unit as well as routine testing of all patients. Negative cases of hepatitis C antibody (confirmed with ELISA 2nd generation and RIBA II Immunoblot methods) were selected and followed for 18 months. Some predisposing factors such as transfusion, duration of hemodialysis, medical procedures including surgery, transplantation, invasive odontology, suspicious sexual contact, diagnostic or therapeutic manipulation, tattooing, and IV drug abuse, were registered and considered. Other rare procedures like acupuncture, manicure and pedicure blood brotherhood rituals, perinatal risk factors, common circumcision rituals and history of abortion were also considered. Ve used a tight control policy through the separation of the rooms within the unit, specific hemodialysis apparatus for suspicious patients and a separate staff caring for the patients. We maintained a low rate of staff turnover in dialysis units and tried to control hepatitis B viral infection. Results: Marital status and living area were significantly related to HCV antibody positivity. It means that more HCV antibody positive cases were observed in married people in urban areas. History of tattooing, medical procedures including surgery, transplantation, invasive odontology and IV drug usage were not significantly related to HCV antibody status. During the follow up, three cases (4.3%) converted to positive. There was a relationship between numbers of hemodialysis per week and HCV antibody positivity (P<0.001). Conclusions: Tight control of transmission routes and severe isolation policy in this study explains an almost ideal decrease in incidence rate of HCV antibody positivity. We suggest periodical screening programs (at least every 6 months) for blood samples that remain in the dialysis apparatus and all procedures used for hemodialysis in these specific patients to achieve a better infection control
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