The article reports the findings of an analysis into student postings on a mobile instant messaging service (WhatsApp) established to develop social presence in a small group of first-year undergraduate radiography students. The analysis was carried out using a validated and reported tool specifically designed to identify categories of social presence, developed using the Community of Enquiry theoretical model. The students themselves undertook the analysis, which enhanced validity due to participant verification of findings. Six hundred posts (approximately 10% of the total year's messages) were analysed at key points in the first-year student journey. In conclusion, WhatsApp was able to provide students with a platform to demonstrate all the characteristics relevant for the development of social presence. In addition, its immediacy appeared to offer benefits over embedded social media platforms such as discussion boards. R ESUM E L'article pr esente les constatations d'une analyse des affichages faits par les etudiants sur un service de Messagerie mobile instantan ee (MMI) (WhatsApp) etabli afin des d evelopper une pr esence sociale au sein d'un petit groupe d' etudiants de premi ere ann ee dans un programme de baccalaur eat en radiographie. L'analyse a et e effectu ee a l'aide d'un outil valid e et pr esent e conçu sp ecialement pour recenser les cat egories de pr esence sociale, d evelopp ees en utilisant le mod ele th eorique de communaut e d'interrogation intellectuelle. Les etudiants eux-mêmes ont effectu e l'analyse, ce qui en augmente la validit e en raison de la v erification des constatations par les etudiants. Six cent affichages (environ 10 % du total de messages de l'ann ee) ont et e analys es a des moments cl es du parcours des etudiants de premi ere ann ee. Conclusion : WhatsApp a et e en mesure de fournir aux etudiants une plateforme leur permettant de d emontrer toutes les caract eristiques pertinentes au d eveloppement de la pr esence sociale. De plus, son instantan eit e semble offrir des avantages sur les plateformes de m edias sociaux int egr ees, comme les forums de discussion.

The synthesis and characterization by single-crystal X-ray diffraction of two thallium salts of the non-co-ordinating anion [B{3,5-(CF3)2C6H3}4] are reported. They possess Tl-Tl contacts supported by Tl-aryl interaction. This cation association overcomes both electrostatic repulsion and cation-anion size and charge matching considerations in the [LTl2L](2+) dications so formed.

Morphological assessment is currently the primary technique for selection of viable embryos for uterine transfer during assisted reproductive techniques, however this method has limited predictive power. The objective of this study was to employ NMR based metabolic profiling analysis of spent embryo culture media to identify novel biomarkers of embryo viability and provide insight into the metabolism of a viable embryo. A total of 37 patients undergoing IVF/ICSI treatment were recruited and 58 media samples were collected from embryos that were transferred back to the uterus. 1 H NMR spectra were acquired and analyzed resulting in the quantification of 12 metabolites in the media samples. Analysis of metabolite ratios revealed significant differences between those patients with positive (n ¼ 27) and negative (n ¼ 31) urinary bhCG results. Some of the most biologically relevant differences include a 17% increase in the formate to glycine ratio and a 22% decrease in the citrate to alanine ratio in the spent embryo media from the positive pregnancy group. Overall, the results indicate that metabolic profiling may provide a means of identifying biomarkers that aid selection of viable embryos.

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