Advanced Diagnostics for the Study of Linearly Polarized Emission. II: Application to Diffuse Interstellar Radio Synchrotron Emission

Diagnostics of polarized emission provide us with valuable information on the Galactic magnetic field and the state of turbulence in the interstellar medium, which cannot be obtained from synchrotron intensity alone. In Paper I (Herron et al. 2017b), we derived polarization diagnostics that are rotationally and translationally invariant in the $Q$-$U$ plane, similar to the polarization gradient. In this paper, we apply these diagnostics to simulations of ideal magnetohydrodynamic turbulence that have a range of sonic and Alfv\'enic Mach numbers. We generate synthetic images of Stokes $Q$ and $U$ for these simulations, for the cases where the turbulence is illuminated from behind by uniform polarized emission, and where the polarized emission originates from within the turbulent volume. From these simulated images we calculate the polarization diagnostics derived in Paper I, for different lines of sight relative to the mean magnetic field, and for a range of frequencies. For all of our simulations, we find that the polarization gradient is very similar to the generalized polarization gradient, and that both trace spatial variations in the magnetoionic medium for the case where emission originates within the turbulent volume, provided that the medium is not supersonic. We propose a method for distinguishing the cases of emission coming from behind or within a turbulent, Faraday rotating medium, and a method to partly map the rotation measure of the observed region. We also speculate on statistics of these diagnostics that may allow us to constrain the physical properties of an observed turbulent region.Comment: 34 pages, 25 figures, accepted for publication in Ap

Enrolment in clinical research at UCLH and geographically distributed indices of deprivation [version 1; peer review: awaiting peer review]

Healthcare should be judged by its equity as well as its quality. Both aspects depend not only on the characteristics of service delivery but also on the research and innovation that ultimately shape them. Conducting a fully-inclusive evaluation of the relationship between enrolment in primary research studies at University College London Hospitals NHS Trust and indices of deprivation, here we demonstrate a quantitative approach to evaluating equity in healthcare research and innovation. We surveyed the geographical locations, aggregated into Lower Layer Super Output Areas (LSOAs), of all England-resident UCLH patients registered as enrolled in primary clinical research studies. We compared the distributions of ten established indices of deprivation across enrolled and non-enrolled areas within Greater London and within a distance-matched subset across England. Bayesian Poisson regression models were used to examine the relation between deprivation and the volume of enrolment standardized by population density and local disease prevalence. A total of 54593 enrolments covered 4401 LSOAs in Greater London and 10150 in England, revealing wide geographical reach. The distributions of deprivation indices were similar between enrolled and non-enrolled areas, exhibiting median differences from 0.26% to 8.73%. Across Greater London, enrolled areas were significantly more deprived on most indices, including the Index of Multiple Deprivation; across England, a more balanced relationship to deprivation emerged. Regression analyses of enrolment volumes yielded weak biases, in favour of greater deprivation for most indices, with little modulation by local disease prevalence. Primary clinical research at UCLH has wide geographical reach. Areas with enrolled patients show similar distributions of established indices of deprivation to those without, both within Greater London, and across distance-matched areas of England. We illustrate a robust approach to quantifying an important aspect of equity in clinical research and provide a flexible set of tools for replicating it across other institutions

Effects of Multivitamin Supplementation on Heart Rate Response in Aerobically Untrained College Aged Students

Multivitamin use is increasingly prevalent in the US among most every population. Yet, previous research noted no performance benefits among individuals following a supplementation period. This study focused on the potential physiological benefits from a three week multivitamin supplementation period using 24 (20.9 ± 2.6yr) aerobically untrained college aged students. Subjects were divided equally into three groups (placebo = PL, multivitamin = MV, control = CL) and asked to perform separate eight minute bouts of exercise, consisting of six min of moderate (60%VO2max) intensity followed immediately by two min of high (85%VO2max) intensity exercise on a cycle ergometer. Following the supplementation period, participants came back and performed the same exercise bout. Heart rates were measured with a POLAR Heart Rate monitor and recorded every two min. Data analysis, using ANOVA comparing the three groups, indicated a statistically significant HR interaction. Post hoc paired t-tests, comparing the pre/post supplementation tests of all groups, noted significant differences in HR between MV group during the 60% VO2 (p = 0.04) intensity bout, and approached significance at 85% VO2 (p = 0.10). No difference occurred for the CL group during either moderate or high intensity exercise. The results indicate that the introduction of a supplement, whether real or placebo, may have a physiological effect on the heart rate of aerobically untrained college students

Can modeling and simulation really help power system designers?

The rap session provided an informal forum for dissemination of information on the state of the art in modeling and simulation of power processing systems. Merits of time domain and frequency domain approaches were debated and the use of these techniques for the prediction of performance and the optimization of a design were discussed. Although it appears that the present state of the art is somethat primative, interest is high and continued progress and improvement should be forthcoming

Synthesis of CdS and CdSe nanocrystallites using a novel single-molecule precursors approach

The synthesis of CdS and CdSe nanocrystallites using the thermolysis of several dithioor diselenocarbamato complexes of cadmium in trioctylphosphine oxide (TOPO) is reported. The nanodispersed materials obtained show quantum size effects in their optical spectra and exhibit near band-edge luminescence. The influence of experimental parameters on the properties of the nanocrystallites is discussed. HRTEM images of these materials show well-defined, crystalline nanosized particles. Standard size fractionation procedures can be performed in order to narrow the size dispersion of the samples. The TOPO-capped CdS and CdSe nanocrystallites and simple organic bridging ligands, such as 2,2¢-bipyrimidine, are used as the starting materials for the preparation of novel nanocomposites. The optical properties shown by these new nanocomposites are compared with those of the starting nanodispersed materials

Survey of Photochemical and Rate Data for Twenty‐eight Reactions of Interest in Atmospheric Chemistry

Photochemical and rate data have been evaluated for 28 gas phase reactions of interest for the chemistry of the stratosphere. The results are presented on data sheets, one per reaction. For each reaction, the available data are summarized. Where possible there is given a preferred value for the rate constant or, for the photochemical reactions, preferred values for primary quantum yields and optical absorption coefficients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87745/2/267_1.pd