1,090 research outputs found

    Gauge Consistent Wilson Renormalization Group II: Non-Abelian Case

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    We give a wilsonian formulation of non-abelian gauge theories explicitly consistent with axial gauge Ward identitities. The issues of unitarity and dependence on the quantization direction are carefully investigated. A wilsonian computation of the one-loop QCD beta function is performed.Comment: 34 pages, 1 eps figure, latex2e. Minor changes, version to appear in Int. J. Mod. Phy

    Nambu-Goldstone Mechanism in Real-Time Thermal Field Theory

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    In a one-generation fermion condensate scheme of electroweak symmetry breaking, it is proven based on Schwinger-Dyson equation in the real-time thermal field theory in the fermion bubble diagram approximation that, at finite temperature TT below the symmetry restoration temperature TcT_c, a massive Higgs boson and three massless Nambu-Goldstone bosons could emerge from the spontaneous breaking of electroweak group SUL(2)×UY(1)UQ(1)SU_L(2)\times U_Y(1) \to U_Q(1) if the two fermion flavors in the one generation are mass-degenerate, thus Goldstone Theorem is rigorously valid in this case. However, if the two fermion flavors have unequal masses, owing to "thermal flactuation", the Goldstone Theorem will be true only approximately for a very large momentum cut-off Λ\Lambda in zero temperature fermion loop or for low energy scales. All possible pinch singularities are proven to cancel each other, as is expected in a real-time thermal field theory.Comment: 11 pages, revtex, no figure, Phys. Rev. D, to appea

    Successful Late Management of Esophageal Perforation with T-Tube Drainage

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    The late management of spontaneous esophageal perforation is the most challenging problem for the surgeon. In this paper, we present a case in whom a spontaneous esophageal perforation was successfully treated by T-tube drainage after unsuccessful conservative treatment. The patient, a 68-year-old male, was admitted to the hospital with sudden upper abdominal pain. After 2 days, esophageal perforation was diagnosed, and conservative management was begun. Thereafter, the subcutaneous emphysema disappeared, and the patient's temperature decreased. However, on day 13, the patient's temperature spiked above 38°C, and computed tomography showed a mediastinal abscess. An emergency left thoracotomy with laparotomy was performed. Since a 2-cm longitudinal perforation with severe inflammatory reactions was observed, the T-tube drainage method was performed. The patient was discharged without postoperative complications and has not experienced any gastrointestinal symptoms, such as gastroesophageal reflux or dysphagia. In conclusion, the T-tube drainage method appears to be a simple and effective method for the late management of esophageal perforation with severe inflammatory reaction

    Quantum phase space distributions in thermofield dynamics

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    It is shown that the the quantum phase space distributions corresponding to a density operator ρ\rho can be expressed, in thermofield dynamics, as overlaps between the state ρ>\mid \rho > and "thermal" coherent states. The usefulness of this approach is brought out in the context of a master equation describing a nonlinear oscillator for which exact expressions for the quantum phase distributions for an arbitrary initial condition are derived.Comment: 17 pages, revtex, no figures. number of pages were incorrectly stated as 3 instead of 17. No other correction

    Thermal Bogoliubov transformation in nuclear structure theory

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    Thermal Bogoliubov transformation is an essential ingredient of the thermo field dynamics -- the real time formalism in quantum field and many-body theories at finite temperatures developed by H. Umezawa and coworkers. The approach to study properties of hot nuclei which is based on the extension of the well-known Quasiparticle-Phonon Model to finite temperatures employing the TFD formalism is presented. A distinctive feature of the QPM-TFD combination is a possibility to go beyond the standard approximations like the thermal Hartree-Fock or the thermal RPA ones.Comment: 8 pages, Proceedings of the International Bogolyubov Conference "Problems of Theoretical and Mathematical Physics", August 23 -- 27, 2009, Dubna, Russi

    Ghost Condensates and Dynamical Breaking of SL(2,R) in Yang-Mills in the Maximal Abelian Gauge

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    Ghost condensates of dimension two in SU(N) Yang-Mills theory quantized in the Maximal Abelian Gauge are discussed. These condensates turn out to be related to the dynamical breaking of the SL(2,R) symmetry present in this gaugeComment: 16 pages, LaTeX2e, final version to appear in J. Phys.

    Local Operations and Completely Positive Maps in Algebraic Quantum Field Theory

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    Einstein introduced the locality principle which states that all physical effect in some finite space-time region does not influence its space-like separated finite region. Recently, in algebraic quantum field theory, R\'{e}dei captured the idea of the locality principle by the notion of operational separability. The operation in operational separability is performed in some finite space-time region, and leaves unchanged the state in its space-like separated finite space-time region. This operation is defined with a completely positive map. In the present paper, we justify using a completely positive map as a local operation in algebraic quantum field theory, and show that this local operation can be approximately written with Kraus operators under the funnel property

    Cigarette smoking and tooth loss experience among young adults: a national record linkage study

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    <p>Abstract</p> <p>Background</p> <p>Various factors affect tooth loss in older age including cigarette smoking; however, evidence regarding the association between smoking and tooth loss during young adulthood is limited. The present study examined the association between cigarette smoking and tooth loss experience among adults aged 20–39 years using linked data from two national databases in Japan.</p> <p>Methods</p> <p>Two databases of the National Nutrition Survey (NNS) and the Survey of Dental Diseases (SDD), which were conducted in 1999, were obtained from the Ministry of Health, Labor and Welfare with permission for analytical use. In the NNS, participants received physical examinations and were interviewed regarding dietary intake and health practices including cigarette smoking, whereas in the SDD, participants were asked about their frequency of daily brushing, and received oral examinations by certified dentists. Among 6,805 records electronically linked via household identification code, 1314 records of individuals aged 20 to 39 years were analyzed. The prevalence of 1+ tooth loss was compared among non-, former, and current smokers. Multiple logistic regression models were constructed including confounders: frequency of tooth brushing, body mass index, alcohol consumption, and intake of vitamins C and E.</p> <p>Results</p> <p>Smoking rates differed greatly in men (53.3%) and women (15.5%). The overall prevalence of tooth loss was 31.4% (31.8% men and 31.1% women). Tooth loss occurred more frequently among current smokers (40.6%) than former (23.1%) and non-smokers (27.9%). Current smoking showed a significant association with 1+ tooth loss in men (adjusted OR = 2.21 [1.40–3.50], P = 0.0007) and women (1.70 [1.13–2.55], P = 0.0111). A significant positive exposure-related relationship between cigarette smoking status and tooth loss was observed (P for trend < 0.0001 and 0.0004 in men and women, respectively). Current smoking was also associated with the prevalence of decayed teeth (1.67 [1.28–2.20], P = 0.0002).</p> <p>Conclusion</p> <p>An association between cigarette smoking and tooth loss was evident among young adults throughout Japan. Due to limitations of the available variables in the present databases, further studies including caries experience and its confounders should be conducted to examine whether smoking is a true risk of premature tooth loss in young adults.</p

    Vacuum structure for expanding geometry

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    We consider gravitational wave modes in the FRW metrics in a de Sitter phase and show that the state space splits into many unitarily inequivalent representations of the canonical commutation relations. Non-unitary time evolution is described as a trajectory in the space of the representations. The generator of time evolution is related to the entropy operator. The thermodynamic arrow of time is shown to point in the same direction of the cosmological arrow of time. The vacuum is a two-mode SU(1,1) squeezed state of thermo field dynamics. The link between expanding geometry, squeezing and thermal properties is exhibited.Comment: Latex file, epsfig, 1 figure, 21 page

    Establishment of Highly Tumorigenic Human Colorectal Cancer Cell Line (CR4) with Properties of Putative Cancer Stem Cells

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    BACKGROUND: Colorectal cancer (CRC) has the third highest mortality rates among the US population. According to the most recent concept of carcinogenesis, human tumors are organized hierarchically, and the top of it is occupied by malignant stem cells (cancer stem cells, CSCs, or cancer-initiating cells, CICs), which possess unlimited self-renewal and tumor-initiating capacities and high resistance to conventional therapies. To reflect the complexity and diversity of human tumors and to provide clinically and physiologically relevant cancer models, large banks of characterized patient-derived low-passage cell lines, and especially CIC-enriched cell lines, are urgently needed. PRINCIPAL FINDINGS: Here we report the establishment of a novel CIC-enriched, highly tumorigenic and clonogenic colon cancer cell line, CR4, derived from liver metastasis. This stable cell line was established by combining 3D culturing and 2D culturing in stem cell media, subcloning of cells with particular morphology, co-culture with carcinoma associated fibroblasts (CAFs) and serial transplantation to NOD/SCID mice. Using RNA-Seq complete transcriptome profiling of the tumorigenic fraction of the CR4 cells in comparison to the bulk tumor cells, we have identified about 360 differentially expressed transcripts, many of which represent stemness, pluripotency and resistance to treatment. Majority of the established CR4 cells express common markers of stemness, including CD133, CD44, CD166, EpCAM, CD24 and Lgr5. Using immunocytochemical, FACS and western blot analyses, we have shown that a significant ratio of the CR4 cells express key markers of pluripotency markers, including Sox-2, Oct3/4 and c-Myc. Constitutive overactivation of ABC transporters and NF-kB and absence of tumor suppressors p53 and p21 may partially explain exceptional drug resistance of the CR4 cells. CONCLUSIONS: The highly tumorigenic and clonogenic CIC-enriched CR4 cell line may provide an important new tool to support the discovery of novel diagnostic and/or prognostic biomarkers as well as the development of more effective therapeutic strategies
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