Cumulative luminosity functions of the X-ray point source population in M31

We present preliminary results from a detailed analysis of the X-ray point sources in the XMM-Newton survey of M31. These sources are expected to be mostly X-ray binaries. We have so far studied 225 of the 535 sources found by automated source detection. Only sources which were present in all three EPIC images were considered. X-ray binaries are identified by their energy spectrum and power density spectrum. Unlike in other surveys we have obtained source luminosities from freely fit emission models. We present uncorrected luminosity functions of the sources analysed so far.Comment: 2 pages, 1 figure. To appear in proceedings of IAUS23

Understanding user communities from social network data

This paper presents an exploratory study, which uses dynamic social network analysis of posts from the Tumblr blogging site relating to the Tate galleries to observe user community change. The findings of this research were presented at the 1st Int. Workshop on Semantic Change & Evolving Semantics (SuCCESS'16) organised by PERICLES partners to explore emerging research in the areas of semantic change and evolving semantics

Quandaries of contract cheating in South African higher education institutions: The way forward

This research aimed to examine the quandaries of contract cheating faced by higher education institutions (HEIs) in South Africa. Based on a desktop study utilizing unobtrusive research methods such as documentary analysis and conceptual analysis of authoritative sources to conceptualise and provide context to contract cheating, the data drew secondary data from published journal articles. Findings demonstrated that the key quandaries of contract cheating are attributed to limited awareness of the concept, the undetectable nature of the action, the lack of law (lacuna) from the national point of view, gaps in existing institutional policies on misconduct, ambiguity in the conceptualisation, and expansion in the availability of this practice as evident in the increase use of custom essay websites, essay mills and file-sharing sites across the globe. To address these challenges, South African HEIs need to acknowledge that contract cheating is a problem which exists in institutions. Therefore, South African HEIs must revisit institutional policies on intellectual integrity and include a delineation of contract cheating, making a clear distinction between plagiarism and collusion. Additionally, South African HEIs must raise awareness of contract cheating amongst their students, invest in software that detects authenticity, such as Authorship Investigate, AI-Emma or Ouriginal, and design student-support-intervention marketing strategies to deter students from turning to contract cheating websites

XMM-Newton reveals ~100 new LMXBs in M31 from variability studies

We have conducted a survey of X-ray sources in XMM-Newton observations of M31, examining their power density spectra (PDS) and spectral energy distributions (SEDs). Our automated source detection yielded 535 good X-ray sources; to date, we have studied 225 of them. In particular, we examined the PDS because low mass X-ray binaries (LMXBs) exhibit two distinctive types of PDS. At low accretion rates, the PDS is characterised by a broken power law, with the spectral index changing from ~0 to ~1 at some frequency in the range \~0.01--1 Hz; we refer to such PDS as Type A. At higher accretion rates, the PDS is described by a simple power law; we call these PDS Type B. Of the 225 sources studied to date, 75 exhibit Type A variability, and are almost certainly LMXBs, while 6 show Type B but not Type A, and are likely LMXBs. Of these 81 candidate LMXBs, 71 are newly identified in this survey; furthermore, they are mostly found near the centre of M31. Furthermore, most of the X-ray population in the disc are associated with the spiral arms, making them likely high mass X-ray binaries (HMXBs). In general these HMXBs do not exhibit Type A variability, while many central X-ray sources (LMXBs) in the same luminosity range do. Hence the PDS may distinguish between LMXBs and HMXBs in this luminosity range.Comment: 4 pages, 2 figures. To appear in proceedings of IAUS230: "Populations of High Energy Sources in Galaxies", 14-19 August 2005, Dublin, Eds E.J.A. Meurs and G. Fabbian

Characteristics of effective interventions promoting healthy eating for preschoolers in childcare settings: an umbrella review

Early Childhood Education and Care (ECEC) settings have a pivotal role in shaping children’s dietary food habits by providing the contextual environment within which they develop these behaviours. This study examines systematic reviews for (1) the effectiveness of interventions to promote healthy eating in children aged 2–5 years attending centre-based childcare; (2) intervention characteristics which are associated with promoting healthy eating and; (3) recommendations for child-health policies and practices. An Umbrella review of systematic reviews was undertaken using a standardized search strategy in ten databases. Twelve systematic reviews were examined using validated critical appraisal and data extraction tools. Children’s dietary food intake and food choices were significantly influenced. Interventions to prevent obesity did not significantly change children’s anthropometric measures or had mixed results. Evidence was more convincing if interventions were multi-component, addressed physical activity and diet, targeted individual-level and environmental-level determinants and engaged parents. Positive outcomes were mostly facilitated by researchers/external experts and these results were not replicated when implemented in centres by ECEC providers without this support. The translation of expert-led interventions into practice warrants further exploration of implementation drivers and barriers. Based on the evidence reviewed, recommendations are made to inform child-health directed practices and policies