28 research outputs found

    Open string wavefunctions in flux compactifications

    Full text link
    We consider compactifications of type I supergravity on manifolds with SU(3) structure, in the presence of RR fluxes and magnetized D9-branes, and analyze the generalized Dirac and Laplace-Beltrami operators associated to the D9-brane worldvolume fields. These compactifications are T-dual to standard type IIB toroidal orientifolds with NSNS and RR 3-form fluxes and D3/D7 branes. By using techniques of representation theory and harmonic analysis, the spectrum of open string wavefunctions can be computed for Lie groups and their quotients, as we illustrate with explicit twisted tori examples. We find a correspondence between irreducible unitary representations of the Kaloper-Myers algebra and families of Kaluza-Klein excitations. We perform the computation of 2- and 3-point couplings for matter fields in the above flux compactifications, and compare our results with those of 4d effective supergravity.Comment: 89 pages, 4 figures. v3: more typos corrected, version published in JHE

    Bieberbach groups and flat manifolds

    No full text

    Combination propranolol and bepridil therapy in stable angina pectoris

    No full text
    The safety and efficacy of bepridil plus propranolol therapy were investigated in a placebo-controlled, parallel-design, double-blind trial in 56 patients who were not responding to propranolol alone. Patients entering the study were receiving an average propranolol dosage of 131 mg/day (range 20 to 240). For the first 2 weeks of the study they were given placebo in addition to their propranolol dose, and then were randomized to receive continued placebo plus propranolol or bepridil plus propranolol therapy. The bepridil dosage was adjusted over the 8 weeks of active treatment to an average of 273 mg/day (range 200 to 400). The double-blind treatment period was followed by a 3-week washout period during which all patients received propranolol and placebo. The effects of treatment on the frequency of angina attacks, nitroglycerin consumption, exercise performance (treadmill-modified Bruce protocol) and Holter electrocardiogram (ECG) were assessed. Propranolol and bepridil plasma levels also were obtained. Improved antianginal efficacy and reduced nitroglycerin consumption were noted when bepridil was added to propranolol (p \u3c 0.01). During 8 weeks of combination treatment, exercise tolerance increased 1.0 ± 1.2 minutes from a baseline of 7.3 ± 2.2 with bepridil plus propranolol compared with an increase of 0.02 ± 1.3 minutes from a baseline of 7.6 ± 2.9 with placebo plus propranolol (p \u3c 0.01). With bepridil plus propranolol, there were also increases in exercise time to onset of angina (p \u3c 0.04), exercise time to 1-mm electrocardiographic ST-segment depression (p \u3c 0.06) and total work (p \u3c 0.03) compared with placebo plus propranolol therapy. Resting heart rate was reduced a maximum of 2 beats/min with combination treatment compared with propranolol alone, and no differences in blood pressure between treatment groups were observed. There were no clinically significant rhythm changes on Holter ECG with combination treatment, and bepridil treatment had no effect on plasma propranolol levels. Bepridil did prolong the QTc interval on resting ECG by a mean of 37 ± 39 millisecond. Adverse effects were mild with bepridil plus propranolol and greater in frequency than those with placebo plus propranolol. With cessation of bepridil, patients returned toward the angina frequency and exercise tolerance levels seen at baseline with propranolol alone. The addition of bepridil to propranolol provided safe and effective antianginal therapy in patients whose angina was not controlled by propranolol alone. © 1985
    corecore