Supernova Environments in Hubble Space Telescope Images

The locations of supernovae in the local stellar and gaseous environment in galaxies contain important clues to their progenitor stars. Access to this information, however, has been hampered by the limited resolution achieved by ground-based observations. High spatial resolution Hubble Space Telescope (HST) images of galaxy fields in which supernovae had been observed can improve the situation considerably. We have examined the immediate environments of a few dozen supernovae using archival post-refurbishment HST images. Although our analysis is limited due to signal-to-noise ratio and filter bandpass considerations, the images allow us for the first time to resolve individual stars in, and to derive detailed color-magnitude diagrams for, several environments. We are able to place more rigorous constraints on the masses of these supernovae. A search was made for late-time emission from supernovae in the archival images, and for the progenitor stars in presupernova images of the host galaxies. In particular, we highlight the results for the Type II SN 1979C in M100. In addition, we have identified the progenitor of the Type IIn SN 1997bs in NGC 3627. We also add to the statistical inferences that can be made from studying the association of SNe with recent star-forming regions

Has the use of computers in radiation therapy improved the accuracy in radiation dose delivery?

Purpose: It is well recognized that computer technology has had a major impact on the practice of radiation oncology. This paper addresses the question as to how these computer advances have specifically impacted the accuracy of radiation dose delivery to the patient. Methods: A review was undertaken of all the key steps in the radiation treatment process ranging from machine calibration to patient treatment verification and irradiation. Using a semi-quantitative scale, each stage in the process was analysed from the point of view of gains in treatment accuracy. Results: Our critical review indicated that computerization related to digital medical imaging (ranging from target volume localization, to treatment planning, to image-guided treatment) has had the most significant impact on the accuracy of radiation treatment. Conversely, the premature adoption of intensity-modulated radiation therapy has actually degraded the accuracy of dose delivery compared to 3-D conformal radiation therapy. While computational power has improved dose calibration accuracy through Monte Carlo simulations of dosimeter response parameters, the overall impact in terms of percent improvement is relatively small compared to the improvements accrued from 3-D/4-D imaging. Conclusions: As a result of computer applications, we are better able to see and track the internal anatomy of the patient before, during and after treatment. This has yielded the most significant enhancement to the knowledge of “in vivo” dose distributions in the patient. Furthermore, a much richer set of 3-D/4-D co-registered dose-image data is thus becoming available for retrospective analysis of radiobiological and clinical responses

Satisfaction with retention factors as predictors of the job embeddedness of medical and information technology services staff

The objective of the study was to determine whether employees’ satisfaction with retention factors (measured by the Retention Factors Scale) significantly predicted their job embeddedness (measured by the Job Embeddedness Scale). A quantitative survey was conducted on a purposive sample (n=206) of early career medical and information technology services staff, identified as scarce skills in a South African client services company. Retention factors such as training and development, career opportunities, supervisor support and the characteristics of the job (skills variety, challenge and autonomy) were shown to significantly predict the participants’ sense of job embeddedness. Satisfaction with training and development opportunities was the best predictor of organisational fit, while satisfaction with career opportunities was the best predictor of organisational sacrifice. The findings add valuable new knowledge that may be used to inform retention strategies for professional staff with scarce skills in the medical and information technology services sector.Key words: retention factors, perceived job embeddedness, training and development, career opportunities, job characteristics, supervisor suppor

Psychological debriefing (PD) of trauma : a proposed model for Africa

CITATION: Van Dyk, E. L. & Van Dyk, G. A. J. 2010. Psychological debriefing (PD) of trauma : a proposed model for Africa. Journal for Transdisciplinary Research in Southern Africa, 6(2):a270, doi:10.4102/td.v6i2.270.The original publication is available at https://td-sa.netAfrica is a continent with severe trauma. Traumatic events include experiences of child soldiers, people living in war and conflict zones, and people struggling with the HIV/AIDS pandemic. These events cause high levels of trauma. The trauma causes psychological disorders like post traumatic stress disorder, acute stress disorder and combat stress reaction, specific in the military environment. This article focuses on a better understanding of the implications of trauma for military people and civilians. It discusses the different theories and models of psychological debriefing. Lastly the article discusses psychological debriefing models for military forces and the civil ian population to prevent severe psychopathology after traumatic incidents in Africa.https://td-sa.net/index.php/td/article/view/270Publisher's versio

Development in adversity: South Africa’s defence industrial participation in perspective

Defence industrial participation (DIP) is a form of countertrade and falls in the sub-category of (defence) offsets. The South African DIP programme played a developmental role in the country’s defence industrial base (DIB), arresting its steady decline since the 1980s. This article discusses the perceived non-achievement of the 1997 DIP objectives and the reality of its manifestations over a 12-year period (2000–2012). It is argued that the DIP tripled the gross national product and improved the economy through the retention of some 58 000 jobs. However, the 2014 Defence Review paves the way for a new defence industrial dispensation. Notwithstanding, there is a need to explore the concomitant ambiguity that exists between perceptions of countertrade and offsets as trade-distorting practices and as value-adding prospects, and to ascertain how this reciprocal trade mechanism could be used better to promote the developmental aims and objectives of governments

Incidence of intraoperative nausea and vomiting during spinal anaesthesia for Caesarean section in two Cape Town state hospitals

Background: Intraoperative nausea and vomiting (IONV) during spinal anaesthesia (SA) for Caesarean section (CS) is unpleasant and may interfere with surgery. The incidence of IONV during elective CS was studied, as well as the influence of ethnicity on this outcome.Methods: A total of 258 healthy term patients undergoing SA for elective CS were recruited to this prospective observational study conducted at two Cape Town Level 2 hospitals. Standard practice was employed for SA for CS at the University of Cape Town: 2 ml hyperbaric bupivacaine plus 10 μg fentanyl at the L3/4 interspace, and 15 mL/kg crystalloid coload. Spinal hypotension was managed with phenylephrine boluses according to a standard protocol. Nausea and/or vomiting were treated by restoration of blood pressure, and metoclopramide. Intraoperative complaints of nausea, and vomiting, were noted. Patients were also interviewed postoperatively as to any experience of intraoperative or previous history of nausea.Results: Of the 258 patients enrolled in the audit, 112 (43.4%) were non-African and 146 (56.6%) were Black African patients. The overall incidence (95% CI) of nausea was 0.32 (0.27–0.38), with 20% occurring prior to and 11% after the delivery. The overall incidence of vomiting was 0.07 (0.05–0.11), with 3.2% occurring prior to and 3.8% after delivery. The incidence of nausea and/or vomiting was 0.33 (0.28 – 0.40). Black Africans experienced significantly less nausea than non-African patients (36/145 [24.8%] vs. 47/112 [42.0%] respectively, p = 0.004). There was no significant difference in the incidence of vomiting (10/145 [6.8%] vs. 8/112 [7.1%] respectively). The odds of experiencing intraoperative nausea for patients with any blood pressure value < 70% of baseline were 2.46 (95% CI 1.40–4.33).Conclusions: Though in keeping with international standards, the clinically significant incidence of nausea and/or vomiting of 33% requires adjustments to the management protocol for spinal hypotension. The inclusion of ethnicity as a risk factor for nausea during SA for CS should be considered.Keywords: Caesarean section, ethnicity, intraoperative, nausea and vomiting, spinal anaesthesi