The construction of a price index for contributions to South African open medical schemes

An accurate measure of the change in the price of medical-scheme cover over time is necessary to inform health and social-security policy, and would provide consumers, employers and the regulator with a useful benchmark. A medical-scheme contribution index based on gross contributions to open medical schemes is constructed using the Paasche formula and a sample of schemes for the period 2006 to 2010. The results of the index indicate a 17,48% increase in real contributions over the period

Age-specific prevalence of cervical human papillomavirus infection and cytological abnormalities in women in Gauteng Province, South Africa

Background. Women accessing the public health system in Gauteng province, South Africa are largely unscreened for cervical cancer andhave a high background prevalence of human immunodeficiency virus (HIV) infection.Objectives. This cross-sectional study describes the age-specific prevalence of human papillomavirus (HPV) infection and cytologicalabnormalities among this urban and peri-urban population.Method. Over the period March 2009 - September 2011, 1 524 women attending public sector primary healthcare clinics were invited toparticipate in a cervical cancer screening study. All participants were screened with conventional cytology and HPV testing undertaken using the HPV linear array genotyping kit (Roche Molecular Systems).Results. Of 1 472 women with valid cytology results, abnormalities were detected in 17.3% (n=255), of which 9.1% (n=134) were high-gradesquamous intraepithelial lesions, and 0.5% (n=8) suggestive of squamous carcinoma. Of the 1 445 women with complete data, the overall and high-risk HPV DNA prevalences were 74.6% (n=1 078) and 54.3% (n=784), respectively. HPV type 16 and/or 18 were detected in 19.5% (n=282) of women. Age-specific prevalence of HPV showed a plateau-shaped curve.Conclusions. The prevalences of HPV infection and abnormal cytology were much higher than previously reported in general populations in South Africa and elsewhere. Higher age-specific prevalence and similar plateau-like age-specific epidemiological curves have previouslyonly been described in studies among HIV-positive women. These findings have implications for planning and development of cervical screening programmes in developing countries with largely unscreened populations with a high background prevalence of HIV

The gender profile of the South African actuarial profession

The aim of this paper is to contextualise the gender status of the South African actuarial profession, both historically and relative to elsewhere in the world, as well as to establish the current level of representation of women in the profession. The authors have investigated the extent to which women are represented in different age groups and at various stages of the qualification process. They find that 85% of Fellow members of the Actuarial Society in 2010 are male but that women represent at least 30% of student members and younger cohorts. Given that people enter the profession primarily from undergraduate degrees in actuarial science, the authors have analysed the relative performance of female students enrolling for an Actuarial Science degree at the University of Cape Town. They find that the proportion of entrants who are female has increased over time but that persistency rates for female students are lower than for male students. They identify the need for further research to establish the underlying reasons for the gender differentials in entrants to university programmes and persistency, and conclude that universities, actuarial employers and the profession have a role to play in improving the perception of the profession and the experiences of women in the classroom and workplace

Quasinormal Modes, the Area Spectrum, and Black Hole Entropy

The results of canonical quantum gravity concerning geometric operators and black hole entropy are beset by an ambiguity labelled by the Immirzi parameter. We use a result from classical gravity concerning the quasinormal mode spectrum of a black hole to fix this parameter in a new way. As a result we arrive at the Bekenstein - Hawking expression of $A/4 l_P^2$ for the entropy of a black hole and in addition see an indication that the appropriate gauge group of quantum gravity is SO(3) and not its covering group SU(2).Comment: 4 pages, 2 figure

On Quasinormal Modes, Black Hole Entropy, and Quantum Geometry

Loop quantum gravity can account for the Bekenstein-Hawking entropy of a black hole provided a free parameter is chosen appropriately. Recently, it was proposed that a new choice of the Immirzi parameter could predict both black hole entropy and the frequencies of quasinormal modes in the large $n$ limit, but at the price of changing the gauge group of the theory. In this note we use a simple physical argument within loop quantum gravity to arrive at the same value of the parameter. The argument uses strongly the necessity of having fermions satisfying basic symmetry and conservation principles, and therefore supports SU(2) as the relevant gauge group of the theory.Comment: 3 pages, revtex4, no figures, discussion expanded and references adde

Kidney cancer and hydrocarbon exposures among petroleum refinery workers.

To evaluate the hypothesis of increased kidney cancer risk after exposure to hydrocarbons, especially those present in gasoline, we conducted a case-control study in a cohort of approximately 100,000 male refinery workers from five petroleum companies. A review of 18,323 death certificates identified 102 kidney cancer cases, to each of whom four controls were matched by refinery location and decade of birth. Work histories, containing an average of 15.7 job assignments per subject, were found for 98% of the cases and 94% of the controls. To each job, industrial hygienists assigned semiquantitative ratings for the intensity and frequency of exposures to three hydrocarbon categories: nonaromatic liquid gasoline distillates, aromatic hydrocarbons, and the more volatile hydrocarbons. Ratings of "present" or "absent" were assigned for seven additional exposures: higher boiling hydrocarbons, polynuclear aromatic hydrocarbons, asbestos, chlorinated solvents, ionizing radiation, and lead. Each exposure had either no association or a weak association with kidney cancer. For the hydrocarbon category of principal a priori interest, the nonaromatic liquid gasoline distillates, the estimated relative risk (RR) for any exposure above refinery background was 1.0 (95% confidence interval [CI] 0.5-1.9). Analyses of cumulative exposures and of exposures in varying time periods before kidney cancer occurrence also produced null or near-null results. In an analysis of the longest job held by each subject (average duration 9.2 years or 40% of the refinery work history), three groups appeared to be at increased risk: laborers (RR = 1.9, 95% CI 1.0-3.9); workers in receipt, storage, and movements (RR = 2.5, 95% CI 0.9-6.6); and unit cleaners (RR = 2.3, 95% CI 0.5-9.9)

Quasinormal modes prefer supersymmetry ?

One ambiguity in loop quantum gravity is the appearance of a free parameter which is called Immirzi parameter. Recently Dreyer has argued that this parameter may be fixed by considering the quasinormal mode spectrum of black holes, while at the price of changing the gauge group to SO(3) rather than the original one SU(2). Physically such a replacement is not quite natural or desirable. In this paper we study the relationship between the black hole entropy and the quasi normal mode spectrum in the loop quantization of N=1 supergravity. We find that a single value of the Immirzi parameter agrees with the semiclassical expectations as well. But in this case the lowest supersymmetric representation dominates, fitting well with the result based on statistical consideration. This suggests that, so long as fermions are included in the theory, supersymemtry may be favored for the consistency of the low energy limit of loop quantum gravity.Comment: 3 page

Influence of surface morphology on the immersion mode ice nucleation efficiency of hematite articles

Abstract. In this paper, the effect of the morphological modification of aerosol particles with respect to heterogeneous ice nucleation is comprehensively investigated for laboratory-generated hematite particles as a model substrate for atmospheric dust particles. The surface area-scaled ice nucleation efficiencies of monodisperse cubic hematite particles and milled hematite particles were measured with a series of expansion cooling experiments using the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) cloud simulation chamber. Complementary off-line characterization of physico-chemical properties of both hematite subsets were also carried out with scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, dynamic light scattering (DLS), and an electro-kinetic particle charge detector to further constrain droplet-freezing measurements of hematite particles. Additionally, an empirical parameterization derived from our laboratory measurements was implemented in the single-column version of the Community Atmospheric Model version 5 (CAM5) to investigate the model sensitivity in simulated ice crystal number concentration on different ice nucleation efficiencies. From an experimental perspective, our results show that the immersion mode ice nucleation efficiency of milled hematite particles is almost an order of magnitude higher at −35.2 °C &lt; T &lt; −33.5 °C than that of the cubic hematite particles, indicating a substantial effect of morphological irregularities on immersion mode freezing. Our modeling results similarly show that the increased droplet-freezing rates of milled hematite particles lead to about one order magnitude higher ice crystal number in the upper troposphere than cubic hematite particles. Overall, our results suggest that the surface irregularities and associated active sites lead to greater ice activation through droplet-freezing. </jats:p

Chandra Observations of Extended X-ray Emission in Arp 220

We resolve the extended X-ray emission from the prototypical ultraluminous infrared galaxy Arp 220. Extended, faint edge-brightened, soft X-ray lobes outside the optical galaxy are observed to a distance of 10 to 15 kpc on each side of the nuclear region. Bright plumes inside the optical isophotes coincide with the optical line emission and extend 11 kpc from end to end across the nucleus. The data for the plumes cannot be fit by a single temperature plasma, and display a range of temperatures from 0.2 to 1 keV. The plumes emerge from bright, diffuse circumnuclear emission in the inner 3 kpc centered on the Halpha peak, which is displaced from the radio nuclei. There is a close morphological correspondence between the Halpha and soft X-ray emission on all spatial scales. We interpret the plumes as a starburst-driven superwind, and discuss two interpretations of the emission from the lobes in the context of simulations of the merger dynamics of Arp 220.Comment: Accepted for publication in ApJ; see also astro-ph/0208477 (Paper 1