Self-monitoring accuracy does not increase throughout undergraduate medical education

Context: Accurate self-assessment of one's performace on a moment-by-moment basis (ie, accurate self-monitoring) is vital for the self-regulation of practising physicians and indeed for the effective regulation of self-directed learning during medical education. However, little is currently known about the functioning of self-monitoring and its co-development with medical knowledge across medical education. This study is the first to simultaneously investigate a number of relevant aspects and measures that have so far been studied separately: different measures of self-monitoring for a broad area of medical knowledge across 10 different performance levels. Methods: This study assessed the self-monitoring accuracy of medical students (n = 3145) across 10 semesters. Data collected during the administration of the formative Berlin Progress Test Medicine (PTM) were analysed. The PTM comprises 200 multiple-choice questions covering all major medical disciplines and organ systems. A self-report indicator (ie, confidence) and two behavioural indicators of self-monitoring accuracy (ie, response time and the likelihood of changing an initial answer to a correct rather than an incorrect item) were examined for their development over semesters. Results: Analyses of more than 390 000 observations (of approximately 250 students per semester) showed that confidence was higher for correctly than for incorrectly answered items and that 86% of items answered with high confidence were indeed correct. Response time and the likelihood of the initial answer being changed were higher when the initial answer was incorrect than when it was correct. Contrary to expectations, no differences in self-monitoring accuracy were observed across semesters. Conclusions: Convergent evidence from different measures of self-monitoring suggests that medical students self-monitor their knowledge on a question-by-question basis well, although not perfectly, and to the same degree as has been found in studies outside medicine. Despite large differences in performance, no variations in self-monitoring across semesters (with the exception of the first semester) were observed

An embedding technique for the solution of reaction-fiffusion equations on algebraic surfaces with isolated singularities

In this paper we construct a parametrization-free embedding technique for numerically evolving reaction-diffusion PDEs defined on algebraic curves that possess an isolated singularity. In our approach, we first desingularize the curve by appealing to techniques from algebraic geometry.\ud We create a family of smooth curves in higher dimensional space that correspond to the original curve by projection. Following this, we pose the analogous reaction-diffusion PDE on each member of this family and show that the solutions (their projection onto the original domain) approximate the solution of the original problem. Finally, we compute these approximants numerically by applying the Closest Point Method which is an embedding technique for solving PDEs on smooth surfaces of arbitrary dimension or codimension, and is thus suitable for our situation. In addition, we discuss the potential to generalize the techniques presented for higher-dimensional surfaces with multiple singularities

The Secret ‘After Life’ of Foraminifera: Big Things Out of Small

Calcareous and siliceous microorganisms are common components of mudrocks, and can be important in terms of stratigraphy and environmental interpretation. In addition, such microorganisms can have a significant ‘after life’, through post-mortem alteration, and represent a potential source of additional information about the diagenetic and deformation history of the rock unit. Some examples of the latter are illustrated in this study from foraminifera within a Cretaceous black shale of Colombia. This includes foraminifera tests acting as understudied repositories of authigenic calcite cement, and of elements such as Ba, Zn, Fe and S through the formation of baryte, sphalerite and iron sulphides (pyrite, marcasite). Such repositories, within the body chambers of foraminiferal tests, can provide important windows into the diagenetic processes within mudstones. If calcite cement is not recognised or separated from biogenic calcite, the depositional calcite budget can be easily overestimated, skewing the application of mudrock classification schemes, and affecting environmental interpretation including that of productivity. The elements Ba, Zn and Fe (often in ratio with Al) are commonly utilised as geochemical proxies of environmental parameters (productivity, bottom water redox conditions, etc.). Therefore, the presence of significant amounts of baryte, sphalerite and pyrite-marcasite (within foraminifera) should be noted and their origins (source and timing) investigated based on their spatial relationships before making environmental deductions based on geochemical analysis alone. Additionally, commonly observed marginal shell damage of many of the observed foraminifera is reported. We interpret this damage, for the first time, as an indicator of lateral dissolution, brought about by horizontal foreshortening during orogenesis. This is also supported by the occurrence of microscale anastomosing horizontal to inclined baryte-filled fractures within the mudstone matrix

Classical ratchet effects in heterostructures with a lateral periodic potential

We study terahertz radiation induced ratchet currents in low dimensional semiconductor structures with a superimposed one-dimensional lateral periodic potential. The periodic potential is produced by etching a grating into the sample surface or depositing metal stripes periodically on the sample top. Microscopically, the photocurrent generation is based on the combined action of the lateral periodic potential, verified by transport measurements, and the in-plane modulated pumping caused by the lateral superlattice. We show that a substantial part of the total current is caused by the polarization-independent Seebeck ratchet effect. In addition, polarization-dependent photocurrents occur, which we interpret in terms of their underlying microscopical mechanisms. As a result, the class of ratchet systems needs to be extended by linear and circular ratchets, sensitive to linear and circular polarizations of the driving electro-magnetic force.Comment: 11 pages, 9 figures, 2 column

Association between the A-2518G polymorphism in the monocyte chemoattractant protein-1 gene and insulin resistance and Type 2 diabetes mellitus

Aims/hypothesis: The molecular mechanisms of obesity-related insulin resistance are incompletely understood. Macrophages accumulate in adipose tissue of obese individuals. In obesity, monocyte chemoattractant protein-1 (MCP-1), a key chemokine in the process of macrophage accumulation, is overexpressed in adipose tissue. MCP-1 is an insulin-responsive gene that continues to respond to exogenous insulin in insulin-resistant adipocytes and mice. MCP-1 decreases insulin-stimulated glucose uptake into adipocytes. The A-2518G polymorphism in the distal regulatory region of MCP-1 may regulate gene expression. The aim of this study was to investigate the impact of this gene polymorphism on insulin resistance. Methods: We genotyped the Ludwigshafen Risk and Cardiovascular Health (LURIC) cohort (n=3307). Insulin resistance, estimated by homeostasis model assessment, and Type 2 diabetes were diagnosed in 803 and 635 patients respectively. Results: Univariate analysis revealed that plasma MCP-1 levels were significantly and positively correlated with WHR (p=0.011), insulin resistance (p=0.0097) and diabetes (p<0.0001). Presence of the MCP-1 G-2518 allele was associated with decreased plasma MCP-1 (p=0.017), a decreased prevalence of insulin resistance (odds ratio [OR]=0.82, 95% CI: 0.70-0.97, p=0.021) and a decreased prevalence of diabetes (OR=0.80, 95% CI: 0.67-0.96, p=0.014). In multivariate analysis, the G allele retained statistical significance as a negative predictor of insulin resistance (OR=0.78, 95% CI: 0.65-0.93, p=0.0060) and diabetes (OR=0.80, 95% CI: 0.66-0.96, p=0.018). Conclusions/interpretation: In a large cohort of Caucasians, the MCP-1 G-2518 gene variant was significantly and negatively correlated with plasma MCP-1 levels and the prevalence of insulin resistance and Type 2 diabetes. These results add to recent evidence supporting a role for MCP-1 in pathologies associated with hyperinsulinaemi

Synthetic tumor-associated glycopeptide antigens.

Glycopeptides with TN antigen (GalNAc)Ser/Thr and T-antigen structures (beta Gall-3GalNAc)Ser/Thr, described as tumor-associated antigens, were synthesized and coupled to bovine serum albumin. Alternatively, synthetic methods for the construction of beta-anomeric analogues of the TN and T-antigen glycopeptides were developed, aiming at antigenic structures having a varied stereochemistry of the linkage between the carbohydrate and the peptide moiety. As a further type of potential tumor-associated antigen, fucosyl-chitobiose asparagine glycopeptides were synthesized, deprotected, and coupled to bovine serum albumin. The chemical methods developed now make the complex sensitive glycoprotein partial structures accessible in analytically pure form and in preparative amounts

Insights into the Electronic Structure of a U(IV) Amido and U(V) Imido Complex

Reaction of the N-heterocylic carbene ligand $^{i}$PrIm (L$^{1}$) and lithium bis(trimethylsilyl)amide (TMSA) as a base with UCl$_{4}$ resulted in U(IV) and U(V) complexes. Uranium\u27s +V oxidation state in (HL$^{1}$)$_{2}$[U(V)(TMSI)Cl$_{5}$] (TMSI=trimethylsilylimido) (2) was confirmed by HERFD-XANES measurements. Solid state characterization by SC-XRD and geometry optimisation of [U(IV)(L$^{1}$)$_{2}$(TMSA)Cl$_{3}$] (1) indicated a silylamido ligand mediated inverse trans influence (ITI). The ITI was examined regarding different metal oxidation states and was compared to transition metal analogues by theoretical calculations