On the waterfall behavior in hybrid inflation

We revisit the hybrid inflation model focusing on the dynamics of the waterfall field in an analytical way. It is shown that inflation may last long enough during the waterfall regime for some parameter regions, confirming the claim of Clesse. In this case the scalar spectral index becomes red, and can fall into the best fit range of the WMAP observation.Comment: 10 pages, 9 figure

Zero Casimir Force in Axion Electrodynamics and New Force Search

We point out that there is a stable configuration of metal plates where the Casimir force is vanishing in axion electrodynamics. We consider a concrete setup involving Weyl semimetals, which hosts an axion-like effect on the electromagnetism, towards the measurement of the axionic effect on the Casimir force. Our setup realizes zero Casimir force between metals and may be useful for the search for new force mediated by light particles at the micrometer scale.Comment: 28 pages, 9 figure

Flow-mediated vasodilation of human epicardial coronary arteries: effect of inhibition of nitric oxide synthesis

AbstractObjectives. This study sought to investigate the role of nitric oxide, an endothelium-derived relaxing factor, in flow-mediated vasodilation in human epicardial coronary arteries.Background. Endothelium-derived relaxing factors may be released from the coronary artery endothelium in response to increases in blood flow.Methods. We studied the effect of the nitric oxide synthesis inhibitor NG-monomethyl-l-arginine (l-NMMA) on the flow-mediated vasodilation of epicardial coronary arteries in 12 patients, using quantitative angiographic and Doppler flow velocity measurements. Adenosine at 100 μg/min was infused into the left anterior descending coronary artery to test the dilator response of the proximal artery to increases in blood flow. Acetylcholine at 3 and 30 μg/min was infused into the left coronary ostium to determine endothelium-dependent vasodilation of the proximal left anterior descending artery. Adenosine and acetykholine were infused before and after the intracoronary infusion ofl-NMMA (25 μg/min for 5 min).Results. Infusion ofl-NMMA caused a significant decrease in the baseline diameter of the proximal left anterior descending artery (from 2.90 ± 0.14 to 2.74 ± 0.13 mm [mean ± SEM], p < 0.01). Adenosine increased coronary blood flow Wore and afterl-NMMA (+3995 ± 27.5% and +511.9 ± 33.3%, respectively). Flow-mediated vasodilation was observed in the proximal left anterior descending artery before and afterl-NMMA (+9.2 ± 1.5%, p < 0.01 and +8.6 ± 2.1%, p < 0.01, respectively). A dose of 3 μg/min of acetylcholine significantly dilated the proximal left anterior descending artery beforel-NMMA (+7.6 ± 1.0%, p < 0.01), but acetylcholine-induced vasodilation was attenuated afterl-NMMA (−1.8 ± 1.0%).Conclusions. Our data suggest that nitric oxide modulates basal coronary artery tone but that mediators other than nitric oxide may be responsible for the flow-mediated vasodilation of human epicardial coronary arteries