Gigahertz Peaked Spectrum sources from the Jodrell Bank-VLA Astrometric Survey

Observations with MERLIN at 408 MHz have been used to establish the low-frequency part of the spectra of more than a hundred compact radio sources taken from the part of the Jodrell Bank--VLA Astrometric Survey limited by 35 deg. < \delta < 75 deg. These sources were selected from JVAS and other catalogues to have convex spectra between 1.4 and 8.4 GHz, characteristic of Gigahertz Peaked Spectrum (GPS) sources. We have confirmed convex shapes of the spectra of 76 objects (one half of our initial candidates) thereby yielding the largest genuine sample of GPS sources compiled so far. Seven of 17 identified quasars in the sample have large (z\ga 2) redshifts.Comment: 18 pages, 2 figures, minor corrections. To appear in: A&A Suppl. vol. 135 (March 1999

Cooperatively enhanced precision of hybrid light-matter sensors

We consider a hybrid system of matter and light as a sensing device and quantify the role of cooperative effects. The latter generically enhance the precision with which modifications of the effective light-matter coupling constant can be measured. In particular, considering a fundamental model of N qubits coupled to a single electromagnetic mode, we demonstrate that the ultimate bound for the precision shows double-Heisenberg scaling: Delta theta proportional to 1/(Nn), with N and n the number of qubits and photons, respectively. Moreover, even using classical states and measuring only one subsystem, a Heisenberg-times-shot-noise scaling, i.e., 1/(N root n) or 1/(n root N), is reached. As an application, we show that a Bose-Einstein condensate trapped in a double-well optical lattice within an optical cavity can in principle be used to detect the gravitational acceleration g with the relative precision of Delta g/g similar to 10(-4) Hz(-1/2). The analytical approach presented in this study takes into account the leakage of photons through the cavity mirrors, and allows one to determine the sensitivity when g is inferred via measurements on atoms or photons

Cooperatively-enhanced precision of hybrid light-matter sensors

We consider a hybrid system of matter and light as a sensing device and quantify the role of cooperative effects. The latter generically enhance the precision with which modifications of the effective light-matter coupling constant can be measured. In particular, considering a fundamental model of $N$ qubits coupled to a single electromagnetic mode, we show that the ultimate bound for the precision shows double-Heisenberg scaling: $\Delta\theta\propto1/(Nn)$, with $N$ and $n$ being the number of qubits and photons, respectively. Moreover, even using classical states and measuring only one subsystem, a Heisenberg-times-shot-noise scaling, i.e. $1/(N\sqrt{n})$ or $1/(n\sqrt{N})$, is reached. As an application, we show that a Bose-Einstein condensate trapped in a double-well potential within an optical cavity can detect the gravitational acceleration $g$ with the relative precision of $\Delta g/g\simeq10^{-9}\text{Hz}^{-1/2}$. The analytical approach presented in this study takes into account the leakage of photons through the cavity mirrors, and allows to determine the sensitivity when $g$ is inferred via measurements on atoms or photons.Comment: 13 pages, 3 figure

Weak CSS Sources from FIRST Survey

We report early results of an observational campaign targeted on a sample of compact steep spectrum sources selected from the FIRST survey which are significantly weaker than those investigated before. The selection criteria and procedure are given in detail. We present here an assortment of MERLIN and VLBI observations and make some general comments based on the morphologies of the sources presented.Comment: A contribution to The Third Workshop on GHz-Peaked Spectrum and Compact Steep Spectrum Radio Sources, Kerastari, Greece, May 28-31, 2002. Refereed and accepted by Publications of the Astronomical Society of Australia. Final version copyedited by PASA Edito

Investigation of methods to produce a uniform cloud of fuel particles in a flame tube

The combustion of a uniform, quiescent cloud of 30-micron fuel particles in a flame tube was proposed as a space-based, low-gravity experiment. The subject is the normal- and low-gravity testing of several methods to produce such a cloud, including telescoping propeller fans, air pumps, axial and quadrature acoustical speakers, and combinations of these devices. When operated in steady state, none of the methods produced an acceptably uniform cloud (+ or - 5 percent of the mean concentration), and voids in the cloud were clearly visible. In some cases, severe particle agglomeration was observed; however, these clusters could be broken apart by a short acoustic burst from an axially in-line speaker. Analyses and experiments reported elsewhere suggest that transient, acoustic mixing methods can enhance cloud uniformity while minimizing particle agglomeration

Metabolism of ticagrelor in patients with acute coronary syndromes.

© The Author(s) 2018Ticagrelor is a state-of-the-art antiplatelet agent used for the treatment of patients with acute coronary syndromes (ACS). Unlike remaining oral P2Y12 receptor inhibitors ticagrelor does not require metabolic activation to exert its antiplatelet action. Still, ticagrelor is extensively metabolized by hepatic CYP3A enzymes, and AR-C124910XX is its only active metabolite. A post hoc analysis of patient-level (n = 117) pharmacokinetic data pooled from two prospective studies was performed to identify clinical characteristics affecting the degree of AR-C124910XX formation during the first six hours after 180 mg ticagrelor loading dose in the setting of ACS. Both linear and multiple regression analyses indicated that ACS patients presenting with ST-elevation myocardial infarction or suffering from diabetes mellitus are more likely to have decreased rate of ticagrelor metabolism during the acute phase of ACS. Administration of morphine during ACS was found to negatively influence transformation of ticagrelor into AR-C124910XX when assessed with linear regression analysis, but not with multiple regression analysis. On the other hand, smoking appears to increase the degree of ticagrelor transformation in ACS patients. Mechanisms underlying our findings and their clinical significance warrant further research.Peer reviewedFinal Published versio