1,114 research outputs found

    Preheating in Supersymmetric Theories

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    We examine the particle production via preheating at the end of inflation in supersymmetric theories. The inflaton and matter scalars are now necessarily complex fields, and their relevant interactions are restricted by holomorphy. In general this leads to major changes both in the inflaton dynamics and in the efficiency of the preheating process. In addition, supersymmetric models generically contain multiple isolated vacua, raising the possibility of non-thermal production of dangerous topological defects. Because of these effects, the success of leptogenesis or WIMPZILLA production via preheating depends much more sensitively on the detailed parameters in the inflaton sector than previously thought.Comment: 24 pages, 3 figures; references adde

    Localized Tachyons and the g_cl conjecture

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    We consider C/Z_N and C^2/Z_N orbifolds of heterotic string theories and Z_N orbifolds of AdS_3. We study theories with N=2 worldsheet superconformal invariance and construct RG flows. Following Harvey, Kutasov, Martinec and Moore, we compute g_cl and show that it decreases monotonically along RG flows- as conjectured by them. For the heterotic string theories, the gauge degrees of freedom do not contribute to the computation of g_cl.Comment: Corrections and clarifications made, 19 page

    Review: The Journal of Dramaturgy, volume 21, issue 2

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    Contents include: Celebrating 25 Years of Review; On African American Dramaturgy One Professional\u27s Personal Response; The Revolution Will Not Be Televised, But Can It Theatricalized?; Tahrir Stories Excerpts From A Verbatim Theatre Project Composed and Performed During the 2011 Egyptian Revolution; Introduction to the review of Burning the House: On Directing and Dramaturgy, by Eugenio Barba; Eugenio Barba\u27s On Directing and Dramaturgy: Burning the House; A Servant of Two or Three or Four or More...Masters, Business Advice for Dramaturgs Working in Virgin Territory; Bryan Doerries\u27s Theater of War, A New Incarnation of an Ancient Ritual. Issue editors: D.J. Hopkins, Sydney Cheek O\u27Donnell, Lauren Beckhttps://soundideas.pugetsound.edu/lmdareview/1042/thumbnail.jp

    National survey of environmental cleaning and disinfection in hospitals in Thailand

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    More than 90% of Thai hospitals surveyed reported implementing environmental cleaning and disinfection (ECD) protocols. Hospital epidemiologist presence was associated with the existence of an ECD checklist (P=.01) and of ECD auditing (P=.001), while good and excellent hospital administrative support were associated with better adherence to ECD protocols (P<.001) and ECD checklists (P=.005). Infect Control Hosp Epidemiol 2017;38:1250-1253

    National survey of practices to prevent health care-associated infections in Thailand: The role of prevention bundles

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    Background We evaluated the practices used in Thai hospitals to prevent catheter-associated urinary tract infection (CAUTI), central line-associated bloodstream infection (CLABSI), and ventilator-associated pneumonia (VAP). Methods From January 1, 2014-November 30, 2014, we surveyed all Thai hospitals with an intensive care unit and at least 250 beds. The use of prevention practices for CAUTI, CLABSI, and VAP was assessed. High compliance (≥75%) with all components of the CLABSI and VAP prevention bundles were determined. CAUTI, CLABSI, and VAP infection rates before and after implementing infection control practices are reported. Multivariable regression was used to examine associations between infection prevention bundle compliance and infection rate changes. Results Out of 245 eligible hospitals, 212 (86.5%) responded. A total of 120 (56.6%) and 115 hospitals (54.2%) reported ≥75% compliance for all components of the CLABSI and VAP prevention bundles, respectively, and 91 hospitals (42.9%) reported using ≥ 4 recommended CAUTI-prevention practices. High compliance with all of the CLABSI and VAP bundle components was associated with significant infection rate reductions (CLABSI, 38.3%; P <.001; VAP, 32.0%; P <.001). Hospitals regularly using ≥ 4 CAUTI-prevention practices did not have greater reductions in CAUTI (0.02%; P =.99). Conclusions Compliance with practices to prevent hospital infections was suboptimal. Policies and interventions promoting bundled approaches may help reduce hospital infections for Thai hospitals

    Review: The Newsletter of the Literary Managers and Dramaturgs of the Americas, volume 15, issue 1

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    Contents include: Dramaturgical Debris, LMDA Conference 2004 Life, Liberty, and the Pursuit of Happiness, The Production Notebooks Edited by Mark Bly: A Conversation between Danielle Mages Amato and D.J. Hopkins, Interviews with Past LMDA Presidents Alexis Greene and David Copelin, and LMDA Regional Updates Issue editors: D.J. Hopkins, Shelley Orr, Megan Monaghan, Madeleine Oldhamhttps://soundideas.pugetsound.edu/lmdareview/1030/thumbnail.jp

    National survey of practices to prevent methicillin- resistant staphylococcus aureus and multidrug-resistant acinetobacter baumannii in Thailand

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    Background. We evaluated the extent to which hospital characteristics, infection control practices, and compliance with prevention bundles impacted multidrug-resistant organism (MDRO) infections in Thai hospitals. Methods. From 1 January 2014 to 30 November 2014, we surveyed all Thai hospitals with an intensive care unit and ≥250 beds. Infection control practices for methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Acinetobacter baumannii (MDR-AB) were assessed. Linear regression was used to examine associations between hospital characteristics and prevention bundle compliance and changes in MDRO infection rates. Results. A total of 212 of 245 (86.5%) eligible hospitals responded. Most hospitals regularly used several fundamental infection control practices for MRSA and MDR-AB (ie, contact precautions, private room/cohorting, hand hygiene, environmental cleaning, and antibiotic stewardship); advanced infection control practices (ie, active surveillance, chlorhexidine bathing, decolonization for MRSA, and hydrogen peroxide vaporizer for MDR-AB) were used less commonly. Facilities with ≥75% compliance with the MRSA prevention bundle experienced a 17.4% reduction in MRSA rates (P = .03). Although the presence of environmental cleaning services (41.3% reduction, P = .01) and a microbiology laboratory (82.8% reduction, P = .02) were among characteristics associated with decreases in MDR-AB rates, greater compliance with the MDR-AB prevention bundle did not lead to reductions in MDR-AB rates. Conclusions. Although fundamental MRSA and MDR-AB control practices are used regularly in most Thai hospitals, compliance with more comprehensive bundled prevention approaches is suboptimal. Improving compliance with bundled infection prevention approaches and promoting the integration of certain hospital factors into infection control efforts may help reduce MDRO infections in Thai hospitals

    Calabi-Yau Fourfolds with Flux and Supersymmetry Breaking

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    In Calabi-Yau fourfold compactifications of M-theory with flux, we investigate the possibility of partial supersymmetry breaking in the three-dimensional effective theory. To this end, we place the effective theory in the framework of general N=2 gauged supergravities, in the special case where only translational symmetries are gauged. This allows us to extract supersymmetry-breaking conditions, and interpret them as conditions on the 4-form flux and Calabi-Yau geometry. For N=2 unbroken supersymmetry in three dimensions we recover previously known results, and we find a new condition for breaking supersymmetry from N=2 to N=1, i.e. from four to two supercharges. An example of a Calabi-Yau hypersurface in a toric variety that satisfies this condition is provided.Comment: 26 page

    Towards a Stringy Resolution of the Cosmological Singularity

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    We study cosmological solutions to the low-energy effective action of heterotic string theory including possible leading order α′\alpha' corrections and a potential for the dilaton. We consider the possibility that including such stringy corrections can resolve the initial cosmological singularity. Since the exact form of these corrections is not known the higher-derivative terms are constructed so that they vanish when the metric is de Sitter spacetime. The constructed terms are compatible with known restrictions from scattering amplitude and string worldsheet beta-function calculations. Analytic and numerical techniques are used to construct a singularity-free cosmological solution. At late times and low-curvatures the metric is asymptotically Minkowski and the dilaton is frozen. In the high-curvature regime the universe enters a de Sitter phase.Comment: 6 pages, 2 Figures; minor revisions; references added; REVTeX 4; version to appear in Phys. Rev.

    Local and macroscopic tunneling spectroscopy of Y(1-x)CaxBa2Cu3O(7-d) films: evidence for a doping dependent is or idxy component in the order parameter

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    Tunneling spectroscopy of epitaxial (110) Y1-xCaxBa2Cu3O7-d films reveals a doping dependent transition from pure d(x2-y2) to d(x2-y2)+is or d(x2-y2)+idxy order parameter. The subdominant (is or idxy) component manifests itself in a splitting of the zero bias conductance peak and the appearance of subgap structures. The splitting is seen in the overdoped samples, increases systematically with doping, and is found to be an inherent property of the overdoped films. It was observed in both local tunnel junctions, using scanning tunneling microscopy (STM), and in macroscopic planar junctions, for films prepared by either RF sputtering or laser ablation. The STM measurements exhibit fairly uniform splitting size in [110] oriented areas on the order of 10 nm2 but vary from area to area, indicating some doping inhomogeneity. U and V-shaped gaps were also observed, with good correspondence to the local faceting, a manifestation of the dominant d-wave order parameter
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