UCT Coatings (United States)

OmegaWhite is a wide-field, high cadence, synoptic survey targeting fields in the southern Galactic plane, with the aim of discovering short period variable stars. Our strategy is to take a series of 39 s exposures in the g band of a 1 square degree of sky lasting 2 h using the OmegaCAM wide field imager on the VLT Survey Telescope (VST). We give an overview of the initial 4 years of data which covers 134 square degrees and includes 12.3 million light curves. As the fields overlap with the VLT Survey Telescope Halpha Photometric Survey of the Galactic plane and Bulge (VPHAS+), we currently have $ugriH\alpha$ photometry for ~1/3 of our fields. We find that a significant fraction of the light curves have been affected by the diffraction spikes of bright stars sweeping across stars within a few dozen of pixels over the two hour observing time interval due to the alt-az nature of the VST. We select candidate variable stars using a variety of variability statistics, followed by a manual verification stage. We present samples of several classes of short period variables, including: an ultra compact binary, a DQ white dwarf, a compact object with evidence of a 100 min rotation period, three CVs, one eclipsing binary with an 85 min period, a symbiotic binary which shows evidence of a 31 min photometric period, and a large sample of candidate delta Sct type stars including one with a 9.3 min period. Our overall goal is to cover 400 square degrees, and this study indicates we will find many more interesting short period variable stars as a result.

We investigate the connection between dark energy and fourth order gravity by analyzing the behavior of scalar perturbations around a Friedmann-Robertson-Walker background. The evolution equations for scalar perturbation are derived using the covariant and gauge invariant approach and applied to two widely studied $f(R)$ gravity models. The structure of the general fourth order perturbation equations and the analysis of scalar perturbations lead to the discovery of a characteristic signature of fourth order gravity in the matter power spectrum, the details of which have not seen before in other works in this area. This could provide a crucial test for fourth order gravity on cosmological scales.

Observed data is often contaminated by undiscovered interlopers, leading to biased parameter estimation. Here we present BEAMS (Bayesian Estimation Applied to Multiple Species) which significantly improves on the standard maximum likelihood approach in the case where the probability for each data point being `pure' is known. We discuss the application of BEAMS to future Type Ia supernovae (SNIa) surveys, such as LSST, which are projected to deliver over a million supernovae lightcurves without spectra. The multi-band lightcurves for each candidate will provide a probability of being Ia (pure) but the full sample will be significantly contaminated with other types of supernovae and transients. Given a sample of N supernovae with mean probability, P, of being Ia, BEAMS delivers parameter constraints equal to NP spectroscopically-confirmed SNIa. In addition BEAMS can be simultaneously used to tease apart different families of data and to recover properties of the underlying distributions of those families (e.g. the Type Ibc and II distributions). Hence BEAMS provides a unified classification and parameter estimation methodology which may be useful in a diverse range of problems such as photometric redshift estimation or, indeed, any parameter estimation problem where contamination is an issue.

Are the unemployed in South Africa ‘pricing themselves out of the labour market;’? This paper explores this proposition through an analysis of reservation wages in Cape Town’s working class district of Khayelitsha/Mitchell’s Plain. It argues that reservation wages are not out of line with predicted wages. This, in turn, suggests that unemployment in the area is not attributable to job seekers having unrealistically high reservation wages.

The measurement of hemoglobin A1c (HbA1c) is critical to the optimal therapeutic management of diabetes. To be most useful, the HbA1c value should be available at the clinical visit. Recently, a number of at-home sampling kits have been developed that facilitate the timely availability of HbA1c results. This is a report of the accuracy, precision (among-subject), and reproducibility (within-subject) of one such kit, B-D A1c, At-Home-Test, which combines a filter paper technique for spotting capillary blood with an immunoturbidometric assay (a variation of the Cobas Integra Hemoglobin A1c method also referred to as Roche Unimate). The B-D A1c At-Home test kit was evaluated in a clinical trial using 1625 dried blood spot samples from 59 subjects diagnosed with type 1 or type 2 diabetes collected in an in-clinic setting. Data for replicate samples were compared against those from the standard Cobas Integra Hemoglobin A1c assay and from the BioRad Variant high-performance liquid chromatography [HPLC] assay. The effects of subjecting the dried spotted blood samples to prolonged elevated temperatures was evaluated in a separate laboratory analysis. The B-D A1c At-Home results, which are highly correlated with the standard Cobas Integra Hemoglobin A1c assay, (r2 = 94.7%), demonstrate excellent within-subject reproducibility for 3- to 10-day-old samples (coefficient of variation = 2.7%), and provide a coefficient of variation for among-subjects that is 3.9%. There were no clinically significant differences (i.e., < 0.3 units) in samples aged 3 to 10 days, between venous or capillary blood samples, or from freezing and thawing or prolonged exposure of B-D A1c At-Home dried blood samples to elevated temperatures before assay. The B-D A1c At-Home kit combines the accuracy, precision, and reproducibility of a clinical laboratory test with the convenience of at-home sample collection. This product may add to the convenience of both patient and health care provider by making it easier for patients to obtain their HbA1c values and have them available at their visit to the clinician.

(1995). The Language of Racism and the Criminal Justice System. South African Journal on Human Rights: Vol. 11, No. 1, pp. 102-122.

A study was designed to test the effects of passive neck flexion (PNF) as compared with active neck flexion (ANF) on the straight-leg-raise (SLR) test.Twenty two subjects were measured three times with a goniometer and the difference in range of movement (ROM) was determined by subtracting the SLR recordings obtained by means of PNF from those of ANF.Results demonstrated that neck flexion (NF) performed actively allowed a mean value of 4,13° more SLR than when performed passively. The implications of these findings are discussed.