Periodic Modulations in an X-ray Flare from Sagittarius A*

We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which lasted a total of about three hours, was detected simultaneously by EPIC on XMM-Newton and the NICMOS near-infrared camera on the HST. Given the inherent difficulty in, and the lack of readily available methods for quantifying the probability of a periodic signal detected over only several cycles in a data set where red noise can be important, we developed a general method for quantifying the likelihood that such a modulation is indeed intrinsic to the source and does not arise from background fluctuations. We here describe this Monte Carlo based method, and discuss the results obtained by its application to a other XMM-Newton data sets. Under the simplest hypothesis that we witnessed a transient event that evolved, peaked and decayed near the marginally stable orbit of the supermassive black hole, this result implies that for a mass of 3.5 x 10^{6} Msun, the central object must have an angular momentum corresponding to a spin parameter of a=0.22.Comment: 4 pages, 6 figures, submitted to ApJ

Does emergency medicine training improve ECG interpretation skills in South Africa?

Includes abstract.Includes bibliographical references (leaves 35-37).The aim of this study is to assess whether ECG interpretation improves with advancing years of Emergency Medicine training in South Africa, and to compare the results with similar international studies. A prospective cross-sectional study of Emergency Medicine registrars and recently qualified emergency physicians was conducted between August 2008 and February 2009 during training sessions at various universities through South Africa. Subjects completed a survey about level of training and experience, previous ECG training and their impression of the current training program and how it could be improved. They were then asked to interpret 10 clinically important ECGs. The trainees in their first and second years of emergency medicine training were compared to their more senior counterparts (third to fifth years)

The Inhomogeneous Wind of the LBV Candidate CygOB2-No.12

We present the results of high-resolution spectroscopy of the extremely luminous star CygOB2-No.12. We identified about 200 spectral features in the range 4552-7939 AA, including the interstellar NaI, KI lines and numerous very strong DIBs, along with the HeI, CII, and SiII lines. An MK spectral type we derived for the object is B4.5Ia+. Our analysis of the radial velocity data shows the presence of a gradient in the stellar atmosphere, caused by both atmospheric expansion and matter infall onto the star. The Halpha emission displays broad Thompson wings, a slightly blue-shifted PCyg type absorption component and a time-variable core absorption. We conclude that the wind is variable in time.Comment: 3 pages, 2 figures, IAU Symposium No.272 "Active OB stars: structure, evolution, mass loss and critical limits", 201

Event Weighted Tests for Detecting Periodicity in Photon Arrival Times

This paper treats the problem of detecting periodicity in a sequence of photon arrival times, which occurs, for example, in attempting to detect gamma-ray pulsars. A particular focus is on how auxiliary information, typically source intensity, background intensity, and incidence angles and energies associated with each photon arrival should be used to maximize the detection power. We construct a class of likelihood-based tests, score tests, which give rise to event weighting in a principled and natural way, and derive expressions quantifying the power of the tests. These results can be used to compare the efficacies of different weight functions, including cuts in energy and incidence angle. The test is targeted toward a template for the periodic lightcurve, and we quantify how deviation from that template affects the power of detection

Meaningful assessment in health technology

Published ArticleThe implementation of the outcomes-based education and training (OBET) and learner-centred approaches specifically in the health technology programmes at the Central University of Technology, Free State (CUT) exposed facilitators to new challenges in teaching and assessment. The current assessment environment in these programmes was established, using two questionnaires aimed at facilitators and students. The results of the study showed a trend towards innovation in assessment and the establishment of an assessment culture when compared with specific characteristics in literature on meaningful and scholarly assessment practices

Die betroubaarheid en faktorstruktuur van die aangepaste meervoudige keuse-formaat van die miner sentence completion scale (MSCS)

The original publication is available at http://www.sajip.co.zaThe reliability and factor structure of the adapted multiple choice version of the Miner Sentence Completion Scale (MSCS). In this study the multiple choice MSCS was adapted as a result of several criticisms thereof. The internal consistency and factor structure of the adapted MSCS were determined to ascertain the reliability and construct validity of the questionnaire. Results show that the internal consistency is unsatisfactory and that the factor structure is so complex that interpretation becomes virtually impossible. In light of the results of this study and other research findings of the psychometric properties of the MSCS, it is recommended that a new measuring instrument for managerial motivation be developed that will enable a valid testing of the managerial rolemotivation theory.Na aanleiding van verskeie punte van kritiek teen die MSCS is die meervoudige keuse-MSCS in hierdie studie aangepas. Ten einde 'n aanduiding van die betroubaarheid en konstrukgeldigheid van die aangepaste MSCS te verkry, is die interne konsekwentheid en faktorstruktuur daarvan bepaal. Die resultate dui daarop dat die interne konsekwentheid onbevredigend en die faktorstruktuur te kompleks vir interpretasie is. In die lig van die bevindinge van hierdie studie, en ander navorsingsbevindinge oor die psigometriese eienskappe van die MSCS, word aanbeveel dat 'n nuwe meetinstrument van bestuursmotivering ontwikkel word wat 'n geldige toetsing van die bestuursrol-motiveringsteorie moontlik sal maak.Publishers' Versio

EVIDENCE OF IMMUNE STIMULATION FOLLOWING SHORT-TERM EXPOSURE TO SPECIFIC EXTREMELY LOW-FREQUENCY ELECTROMAGNETIC FIELDS

Published ArticleThere is increasing evidence that extremely low frequency (ELF) electromagnetic fields (EMFs) interact with immune cells. Even more evident is that immune cells are activated when exposed to these fields for a short period. Signal specificity and dosimetry appear to play a role. In this study, four groups of laboratory mice received daily exposure to a specific electromagnetic field with an intensity of 5μT for one hour, four hours and twenty-four hours (continuously) respectively for a period of seven days. The control group received no exposure and was used as standard for comparison. Following exposure, whole blood was analysed for leukocyte count, CD3, CD4, CD8 and CD19 analysis. The results for the twenty-four hour exposure group indicated increased total leukocyte, lymphocyte, CD3 and CD4 values and a decreased neutrophil values. These findings provide evidence that the immune system is indeed stimulated by exposure to EMFs

The Delphi technique as a tool to evaluate a concept CPD framework to be implemented by medical technologists in South Africa

Published ArticleA concept CPD framework, to be implemented by medical technology workers, was compiled and needed to be evaluated by professionals. The aim of this survey was therefore to use the Delphi technique as a research tool to evaluate the concept CPD framework by a widely distributed group of medical technology workers. The Delphi technique is a research tool organizing group communication in gaining consensus among a panel of experts. A monitoring team co-ordinated and evaluated the Delphi process in response to the feedback received by a panel of experts. Panellists are selected for their contribution to the topic under investigation. They do not normally interact with one another during the Delphi rounds. Fifteen panellists, distributed throughout South Africa, participated. The panellists were knowledgeable about medical technology and CPD. During the three Delphi rounds, statements were added, moderated, rephrased and rated. This resulted in a final CPD framework that consisted of 71 statements, completed within the three months scheduled time frame with a very high percentage co-operation of the panellists. The Delphi technique was an ideal tool for evaluating the concept CPD framework among a widely distributed group of medical technology workers

Human health aspects related to the ingestion of geophagic clayey soils from the Free State and Limpopo provinces, South Africa

Published ArticleStudies were undertaken in the Limpopo and Free State Provinces of South Africa to understand the beliefs, perceptions and health implications associated with geophagia. Questionnaires administered to 225 geophagic females covered their demographic details, their reasons for ingesting geophagic clayey soils and their perceptions regarding associated health conditions and implications. Respondents ingested clayey soils for body cleansing, craving, nutrient supplementation and weight loss. Some respondents considered the soils harmful, and < 50% of respondents had some knowledge of the contents of soils they ingested. Medical reasons in support of geophagia included lack of knowledge on the health implications of the practice. Medical consequences associated with geophagia may have occurred as a result of a lack of knowledge of the health implications of the practice. A clear need for educating geophagic individuals regarding the health implications of geophagia is called for

Shadowing Effects on the Nuclear Suppression Factor, R_dAu, in d+Au Interactions

We explore how nuclear modifications to the nucleon parton distributions affect production of high transverse momentum hadrons in deuteron-nucleus collisions. We calculate the charged hadron spectra to leading order using standard fragmentation functions and shadowing parameterizations. We obtain the d+Au to pp ratio both in minimum bias collisions and as a function of centrality. The minimum bias results agree reasonably well with the BRAHMS data while the calculated centrality dependence underestimates the data and is a stronger function of p_T than the data indicate.Comment: 18 pages, 3 figures, final version, Phys. Rev. C in pres