294 research outputs found

    A Content Analysis of Interviewee Reports of Medical School Admissions Interviews

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    Introduction. Prospective medical school applicants use Internet websites to gain information about medical school interviews as well as to offer their experience in such interviews. This study examined applicants’ reported experiences of interviews and compared them to the purposes of the interview as purported by medical schools. Method. Content analysis of student feedback regarding medical school interviews at 161 medical schools was conducted for entries of over 4600 students applying to medical school who anonymously and voluntarily completed an online questionnaire. Results. Across all medical schools, nearly one half of all cited interview questions addressed non-cognitive characteristics of the applicants. Top ranked medical schools were reported to ask significantly more interpersonal and illegal questions and fewer academic/general knowledge questions than other medical schools. Lower ranked schools did not differ significantly in the types of questions reportedly asked applicants compared to other medical schools. Discussion. Medical school interviews are generally gathering types of information about applicants that admissions personnel identify as important in the admission decision. In addition to measuring interpersonal characteristics, medical school admissions interviews are assessing cognitive abilities and ethical decision-making. Sources on the Internet provide actual medical school interview questions to prospective students. This practice can help them gain an undue advantage in interviewing. Admissions committees and faculty who interview students may want to consider how best to obtain accurate and valid responses from applicants

    Annual Report 2018/19: Institute for Nuclear Waste Disposal

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    Systematic XAS study on the reduction and uptake of Tc by magnetite and mackinawite

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    The mechanisms for the reduction and uptake of Tc by magnetite (Fe3O4) and mackinawite (FeS) are investigated using X-ray absorption spectroscopy (XANES and EXAFS), in combination with thermodynamic calculations of the Tc/Fe systems and accurate characterization of the solution properties (pHm, pe, [Tc]). Batch sorption experiments were performed under strictly anoxic conditions using freshly prepared magnetite and mackinawite in 0.1 M NaCl solutions with varying initial Tc(VII) concentrations (2 × 10−5 and 2 × 10−4 M) and Tc loadings (400–900 ppm). XANES confirms the complete reduction of Tc(VII) to Tc(IV) in all investigated systems, as predicted from experimental (pHm + pe) measurements and thermodynamic calculations. Two Tc endmember species are identified by EXAFS in the magnetite system, Tc substituting for Fe in the magnetite structure and Tc–Tc dimers sorbed to the magnetite {111} faces through a triple bond. The sorption endmember is favoured at higher [Tc], whereas incorporation prevails at low [Tc] and less alkaline pH conditions. The key role of pH in the uptake mechanism is interpreted in terms of magnetite solubility, with higher [Fe] and greater recrystallization rates occurring at lower pH values. A TcSx-like phase is predominant in all investigated mackinawite systems, although the contribution of up to 20% of TcO2·xH2O(s) (likely as surface precipitate) is observed for the highest investigated loadings (900 ppm). These results provide key inputs for an accurate mechanistic interpretation of the Tc uptake by magnetite and mackinawite, so far controversially discussed in the literature, and represent a highly relevant contribution to the investigation of Tc retention processes in the context of nuclear waste disposal

    Recent advances in the aqueous chemistry of the calcium(II)-gluconate system – Equilibria, structure and composition of the complexes forming in neutral and in alkaline solutions

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    Of the sugar carboxylates, D-gluconate is clearly the most significant representative: the world’s annual production of this organic compound is estimated to be in the order of 105^{5} tonnes. The reason of its mass production is due to its outstandingly broad range of practical (medical, pharmaceutical, industrial, etc.) applications. D-gluconate is a well-known and exceptionally popular complexing agent; accordingly, it has been the subject of a large number of coordination chemical research investigations. Its complexation properties are specially remarkable in alkaline to hyperalkaline pH conditions, where the deprotonation of one or more of its alcoholic OH groups provides a favourable frame for the formation of very stable chelate complexes with a large variety of metal cations. With the aim to show the state of the art of some relevant issues in the aqueous chemistry of the D-gluconate ion, the current paper focusses on the acidbase properties and calcium(II) complexation of the compound encompassing the entire experimentally available pH-range in water. The accessible literature on the deprotonation of carboxylic and alcoholic OH groups is collected and critically evaluated. The lactonization equilibria of D-gluconic acid are also scrutinized. The available data on the calcium complexes forming in neutral and in (hyper)alkaline solutions (both in terms of composition, formation constants and solution structure) are also discussed. Where feasible, some of these properties are compared with those of D-glucose and its derivatives as well as some less common sugar carboxylates, structurally related to D-gluconate, (i.e., D-heptagluconate, Lgulonate and α-D-isosaccharinate). Special emphasis is laid on the relationship between complex stability and the type of metal-binding groups
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