2,248 research outputs found

    On L2L^2 -functions with bounded spectrum

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    We consider the class PW(Rn)PW(\mathbb R^n) of functions in L2(Rn)L^2(\mathbb R^n), whose Fourier transform has bounded support. We obtain a description of continuous maps φ:Rm→Rn\varphi : \mathbb R^m\rightarrow\mathbb R^n such that f∘φ∈PW(Rm)f\circ\varphi\in PW(\mathbb R^m) for every function f∈PW(Rn)f\in PW(\mathbb R^n). Only injective affine maps φ\varphi have this property

    Thermal behaviors of light unflavored tensor mesons in the framework of QCD sum rule

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    In this study, we investigate the sensitivity of the masses and decay constants of the light f2(1270)f_{2}(1270) and a2(1320)a_{2}(1320) tensor mesons to the temperature using QCD sum rule approach. In our calculations, we take into account the additional operators appearing in operator product expansion at finite temperature. It is obtained that at deconfinement temperature the decay constants and masses decrease with amount of 6%6\% and 96%96\% compared to their vacuum values, respectively. Our results on the masses at zero temperature are consistent with the vacuum sum rules predictions as well as the experimental data.Comment: 4 Pages and 1 Table, Prepared for the proceeding of the 4th International Conference on Hadron Physics (TROIA'14

    Thermal QCD Sum Rules Study of Vector Charmonium and Bottomonium States

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    We calculate the masses and leptonic decay constants of the heavy vector quarkonia, J/ψJ/\psi and Υ\Upsilon mesons at finite temperature. In particular, considering the thermal spectral density as well as additional operators coming up at finite temperature, the thermal QCD sum rules are acquired. Our numerical calculations demonstrate that the masses and decay constants are insensitive to the variation of temperature up to T≅100 MeVT\cong 100 ~MeV, however after this point, they start to fall altering the temperature. At deconfinement temperature, the decay constants attain roughly to 45% of their vacuum values, while the masses are diminished about 12%, and 2.5% for J/ψJ/\psi and Υ\Upsilon states, respectively. The obtained results at zero temperature are in good consistency with the existing experimental data as well as predictions of the other nonperturbative models. Considerable decreasing in the values of the decay constants can be considered as a sign of the quark gluon plasma phase transition.Comment: 14 Pages, 8 Figures and 2 Table

    Iranian Dietary Patterns and Risk of Colorectal Cancer

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    Background: Role of diet on colorectal cancer (CRC) has been considered in terms of single foods and nutrients, but less frequently in terms of dietary patterns in Iran. The objective of this study was to determine the association between Iranian dietary patterns and CRC. Methods: This case-control study was conducted in four hospitals in Tabriz City of Iran including 414 participants aged 35-75 years: 207 cases with CRC confirmed by pathology and colonoscopy findings were selected and 207 controls free of neoplastic conditions and diet-related chronic diseases (from the same hospital at the same period for the cases). Dietary data were assessed using a 123-item semi-quantitative food frequency questionnaire. Two dietary patterns were found by using of Principal Component Analysis (PCA) method;"Healthy pattern" and "Iranian pattern". Multivariate logistic regression analysis was used to estimate adjusted odds ratios (OR) for relationship between dietary patterns and colorectal cancer. Results: After adjusting for confounding factors, the Iranian dietary pattern was significantly associated with an increased odds of colorectal cancer (OR=1.46; 95 Confidenec Interval (CI)=1.05-2.19) while a reduced odds of colorectal cancer was observed with the Healthy dietary pattern (OR=0.18; 95 CI=0.091-0.47). Conclusion: Iranian dietary pattern (IDP) seems to increase the odds of colorectal cancer and protective effect of Healthy dietary pattern
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