Unravelling early endovascular skill acquisition:Using psychometric predictors and multimodal magnetic resonance imaging

The structure of the brain changes as a result of learning to perform a new medical procedure In this research project, we studied what happens in the brain when medical students acquire the skills needed to perform a procedure called endovascular intervention (EI). Endovascular interventions are used to treat vascular disease, the most well-known application area is the treatment of a narrowed coronary artery. What makes learning how to perform such a procedure quite difficult is that, as opposed to open surgery, an EI is conducted via a small skin incision under x-ray guidance. As a result, there is neither direct access to nor direct sight onto the treatment site. Although these procedures are widely used, it is not clear how to best train residents to perform EIs safely. Therefore, we investigated the development of the skills needed to conduct an EI on a behavioural and brain level and tested whether pre-existing abilities influence the learning process. We trained medical students to perform an EI on a medical simulator and conducted non-invasive magnetic resonance imaging (MRI) scans to assess their brain structure before and after training. Before training, participants completed cognitive and fine-motor ability tests. We found that participants who scored higher on a test that measured mental rotation ability improved more rapidly during endovascular training. Intriguingly, our MRI data showed that the brain of participants who trained this medical skill adapted to the new demands: the volume of grey matter in the intraparietal sulcus- a brain structure crucial for hand-eye coordination- had increased in comparison to a control group. Our results identified the brain regions involved and the crucial sub-skills that are necessary to perform EIs and thus may have important implications for training endovascular interventions

A spatial panel approach to the east German wage curve

This study presents results about wage effects of unemployment in eastern Germany. The standard approach to analyse the wage curve takes no account of the spatial relationship among regions. Ignoring this relationship may seriously bias the results. To investigate this, the East German wage curve is estimated including spatial effects using panel data classified into 114 administrative districts over the period 1993-1999. It extends the analysis of Baltagi, Blien and Wolf (2000) in which spatial effects were not taken into account. To control for the possible endogeneity of the unemployment rate, one of the explanatory variables, instrumental variable methods should be used. To control for spatial dependence, this paper adopts the use of matrix exponentials for spatially transforming the error terms. This transformation has the advantage that the Jacobian term equals zero. Two important empirical results appear. If spatial effects are not taken into account, the unemployment elasticity in Eastern Germany is larger than in Western countries. If spatial effects are added, the unemployment elasticity significantly reduces.

Estimating Poverty and Inequality Indicators using Interval Censored Income Data from the German Microcensus

Rising poverty and inequality increases the risk of social instability in countries all around the world. For measuring poverty and inequality there exists a variety of statistical indicators. Estimating these indicators is trivial as long as the income variable is measured on a metric scale. However, estimation is not possible, using standard formulas, when the income variable is interval censored (or grouped), as in the German Microcensus. This is the case for numerous censuses due to confidentiality constraints or in order to decrease item non-response. To enable the estimation of statistical indicators in these scenarios, we propose an iterative kernel density algorithm that generates metric pseudo samples from the interval censored income variable. Based on these pseudo samples, poverty and inequality indicators are estimated. The standard errors of the indicators are estimated by a non-parametric bootstrap. Simulation results demonstrate that poverty and inequality indicators from interval censored data can be unbiasedly estimated by the proposed kernel density algorithm. Also the standard errors are correctly estimated by the non-parametric bootstrap. The kernel density algorithm is applied in this work to estimate regional poverty and inequality indicators from German Microcensus data. The results show the regional distribution of poverty and inequality in Germany

A Clumpy Stellar Wind and Luminosity-Dependent Cyclotron Line Revealed by The First Suzaku Observation of the High-Mass X-ray Binary 4U 1538-522

We present results from the first Suzaku observation of the high-mass X-ray binary 4U 1538-522. The broad-band spectral coverage of Suzaku allows for a detailed spectral analysis, characterizing the cyclotron resonance scattering feature at $23.0 \pm 0.4$ keV and the iron K$\alpha$ line at $6.426 \pm 0.008$ keV, as well as placing limits on the strengths of the iron K$\beta$ line and the iron K edge. We track the evolution of the spectral parameters both in time and in luminosity, notably finding a significant positive correlation between cyclotron line energy and luminosity. A dip and spike in the lightcurve is shown to be associated with an order-of-magnitude increase in column density along the line of sight, as well as significant variation in the underlying continuum, implying the accretion of a overdense region of a clumpy stellar wind. We also present a phase-resolved analysis, with most spectral parameters of interest showing significant variation with phase. Notably, both the cyclotron line energy and the iron K$\alpha$ line intensity vary significantly with phase, with the iron line intensity significantly out-of-phase with the pulse profile. We discuss the implications of these findings in the context of recent work in the areas of accretion column physics and cyclotron resonance scattering feature formation.Comment: 15 pages, 8 figures. Accepted to ApJ on 2 July 201

Tactile Working Memory Capacity of Users Who Are Blind in an Electronic Travel Aid Application with a Vibration Belt

Electronic travel aids (ETAs) can increase the safety and comfort of pedestrians who have a visual impairment by displaying obstacles through a vibrotactile navigation belt. Building a complete picture of relevant obstacles and finding a safe route requires ETA users to integrate vibrotactile cues over time and space in their tactile working memory. Previous research suggests that the sense of touch exhibits a working memory that has characteristics similar to vision and audition. However, the capacity of the tactile working memory and the effects of secondary tasks are still under-researched. We investigated tactile working memory capacity of 14 adolescent participants who are blind in an immediate, whole report recall test. Participants received trials consisting of one to five vibration patterns presented sequentially at different locations on their torso representing obstacles with a direction (vibration location) and distance (vibration pattern). Recall performance was assessed under four conditions: baseline and with distracting background sounds and/or while walking with the long cane. Both walking and ignoring distracting sounds are relevant for everyday use of an ETA and were expected to decrease memory performance. We calculated the 75% correct scores for two memory performance measures: the number of items in a trial (numerosity), and item location and pattern correct. In the baseline condition, the scores were close to ceiling (i.e., 5 items). However, in the presence of distracting sounds and while walking, the scores were reduced to 3.2 items for numerosity and 1.6 items for location and identity correct. We recommend using 2 items as the maximum tactile working memory load in an applied setting unless users are trained and/or can adopt their strategy without unacceptable costs, such as reducing their walking speed

Walking Paths to and from a Goal Differ: On the Role of Bearing Angle in the Formation of Human Locomotion Paths

The path that humans take while walking to a goal is the result of a cognitive process modulated by the perception of the environment and physiological constraints. The path shape and timing implicitly embeds aspects of the architecture behind this process. Here, locomotion paths were investigated during a simple task of walking to and from a goal, by looking at the evolution of the position of the human on a horizontal (x,y) plane. We found that the path while walking to a goal was not the same as that while returning from it. Forward-return paths were systematically separated by 0.5-1.9m, or about 5% of the goal distance. We show that this path separation occurs as a consequence of anticipating the desired body orientation at the goal while keeping the target in view. The magnitude of this separation was strongly influenced by the bearing angle (difference between body orientation and angle to goal) and the final orientation imposed at the goal. This phenomenon highlights the impact of a trade-off between a directional perceptual apparatus-eyes in the head on the shoulders-and and physiological limitations, in the formation of human locomotion paths. Our results give an insight into the influence of environmental and perceptual variables on human locomotion and provide a basis for further mathematical study of these mechanisms

Motion optimization and parameter identification for a human and lower-back exoskeleton model

Designing an exoskeleton to reduce the risk of low-back injury during lifting is challenging. Computational models of the human-robot system coupled with predictive movement simulations can help to simplify this design process. Here, we present a study that models the interaction between a human model actuated by muscles and a lower-back exoskeleton. We provide a computational framework for identifying the spring parameters of the exoskeleton using an optimal control approach and forward-dynamics simulations. This is applied to generate dynamically consistent bending and lifting movements in the sagittal plane. Our computations are able to predict motions and forces of the human and exoskeleton that are within the torque limits of a subject. The identified exoskeleton could also yield a considerable reduction of the peak lower-back torques as well as the cumulative lower-back load during the movements. This work is relevant to the research communities working on human-robot interaction, and can be used as a basis for a better human-centered design process

Factor structure and psychometric properties of the trier inventory for chronic stress (TICS) in a representative german sample

<p>Abstract</p> <p>Background</p> <p>Chronic stress results from an imbalance of personal traits, resources and the demands placed upon an individual by social and occupational situations. This chronic stress can be measured using the Trier Inventory for Chronic Stress (TICS). Aims of the present study are to test the factorial structure of the TICS, report its psychometric properties, and evaluate the influence of gender and age on chronic stress.</p> <p>Methods</p> <p>The TICS was answered by <it>N </it>= 2,339 healthy participants aged 14 to 99. The sample was selected by random-route sampling. Exploratory factor analyses with Oblimin-rotated Principal Axis extraction were calculated. Confirmatory factor analyses applying Robust Maximum Likelihood estimations (MLM) tested model fit and configural invariance as well as the measurement invariance for gender and age. Reliability estimations and effect sizes are reported.</p> <p>Results</p> <p>In the exploratory factor analyses, both a two-factor and a nine-factor model emerged. Confirmatory factor analyses resulted in acceptable model fit (RMSEA), with model comparison fit statistics corroborating the superiority of the nine-factor model. Most factors were moderately to highly intercorrelated. Reliabilities were good to very good. Measurement invariance tests gave evidence for differential effects of gender and age on the factor structure. Furthermore, women and younger individuals, especially those aged 35 to 44, tended to report more chronic stress than men and older individuals.</p> <p>Conclusions</p> <p>The proposed nine-factor structure could be factorially validated, results in good scale reliability, and heuristically can be grouped by two higher-order factors: "High Demands" and "Lack of Satisfaction". Age and gender represent differentiable and meaningful contributors to the perception of chronic stress.</p

Heilsbringer der Laien: Die Seitenwunde Christi als mittelalterliches Andachtsbild

Die Arbeit zeichnet erstmals die Genese der Darstellung der Seitenwunde Christi als Einzelbild nach. Der Fokus liegt hierbei nicht nur auf der Entwicklung und Verbreitung dieses spezifischen Andachtsbildes, sondern auch darauf, ein besseres Verständnis für die Laienfrömmigkeit und die ihr immanenten Praktiken im ausgehenden Mittelalter zu erlangen. Um die Grundlagen dieser Andachtspraxis zu begreifen, wird die Fülle des Materials der Seitenwunden-Verehrung von den frühen patristischen Quellen bis hin zur spätmittelalterlichen Wundenadoration in Schrift- und Bildzeugnissen dargelegt. Während in bisherigen kunsthistorischen Forschungsbeiträgen nur wenige einzelne Bildbeispiele betrachtet wurden, zeigt diese Arbeit eine Vielzahl bislang nicht beachteter Bildwerke, die eine Katalogisierung der Seitenwunden-Darstellungen ermöglichen. Mithilfe dieses umfangreichen Werkkorpus werden sowohl die regionale Verbreitung als auch die außergewöhnlichen Variationen innerhalb der Wundenbilder und die damit zusammenhängenden unterschiedlichen ikonografischen Traditionen und Präferenzen nachgewiesen. Neben der Darlegung der Genealogie der spätmittelalterlichen Seitenwunden-Bilder stellt die Erschließung ihres umfangreichen Sinngehalts ein Novum im Forschungsdiskurs dar. Die Bilder der heiligen Wunde verstehen sich als Zeugnisse persönlich gelebter Frömmigkeit, welche Einblicke in die mittelalterliche Lebenswelt laikaler Bevölkerungsschichten ermöglichen. Gerade ihr Bezug zu individuellen Schutz- und Glaubensvorstellungen dient dabei als Abbild realer Lebenswirklichkeiten. Diese Forschungsergebnisse eröffnen nicht nur für die Kunstgeschichte fruchtbare Erkenntnisse, sondern lassen sich auch innerhalb von Theologie, Germanistik, Soziologie und Geschichte anwenden. Die Bilder der Seitenwunde dienen dabei als ein Beispiel, um die Vieldeutigkeit christlicher Kunst zu belegen. Die Varianz der mit ihnen verknüpften Themen zeigt, wie wenig ästhetische Codierung, handwerkliche Ausführung und gesellschaftsrelevante Bedeutung in Abhängigkeit zueinanderstehen müssen. Unter diesem Aspekt wird auch ersichtlich, wie ergebnisreich die Betrachtung einfacher, mitunter grotesk anmutender Zeugnisse ausfallen kann. Die Bilder der Seitenwunde könnten auf den ersten Blick als absurdes Randphänomen eingestuft werden, ihre eingehende Analyse zeigt aber, dass sie nicht nur inhaltlich äußerst komplex sind, sondern dass sie auch weitaus deutlicher als andere Werke die alltägliche christliche Lebenswelt abzubilden vermögen. Die unbarmherzige Lebensrealität des Spätmittelalters bedingte die Erhöhung des Symbols der Wunde. Als Ausdruck göttlicher Macht, himmlischen Beistandes und der Erlösung wurden die Wunden Christi demnach nicht nur Referenz der Passion, sondern auch seelischer Beistand innerhalb eines Lebens voller Ängste und Entbehrungen.:1. Einleitung 4 2. Theologische Grundlagen der Seitenwunden-Verehrung 12 2.1. Zeugnisse der christlichen Antike 13 2.1.1 Neues Testament 13 2.1.2 Exegese der Kirchenväter 17 2.1.3 Übersicht zur Motivgeschichte der Patristik 38 2.2 Mittelalterliche Überlieferung 39 2.3. Mystische Betrachtungen und Laienfrömmigkeit des Spätmittelalters 48 3. Die Seitenwunde Christi als spätmittelalterliches Andachtsbild 64 3.1. Der Urtypus 65 3.2. Die Darstellung der Seitenwunde Christi bis 1400 71 3.2.1 Französische Gebiete 71 3.2.2 Gebiete des Heiligen Römischen Reiches 79 3.2.3 Englische Gebiete 90 3.3. Die Darstellung der Seitenwunde Christi bis 1500 98 3.3.1 Vertikale Konzepte 99 3.3.2 Horizontale Konzepte 107 3.3.3 Die Wunde im Kelch 111 3.3.4 Die Wunde auf dem Tuch 119 3.3.5 Modellieren der Formgebung: Die Raute als Inbegriff der Seitenwundenbilder des späten 15. Jahrhunderts 124 3.3.6 Einzelfunde 137 3.4 Entwicklungen der folgenden Jahrhunderte 144 4. Mandorla vs. Raute – Ursprünge der Formgebung 150 4.1 Aureole, Strahlenkranz, Mandorla – Licht als multireligiöser Ausdruck des Göttlichen 150 4.2 Form als Sinnbild – Ursprünge geometrischer Bildschemen 157 4.3 Verbildlichungen des Corpus Christi 166 4.4 Zur Vieldeutigkeit christlicher Kunst – eine exemplarische Analyse 168 5. Vulnus oder Vulva? Zur Geschlechtsspezifik der Wundöffnung 186 5.1 Sexualität im Mittelalter 187 5.2 Christliche Vorstellungen eines allgeschlechtlichen Gottes 196 5.3 Die heilige Wunde und ihre Geschlechtlichkeit 202 6. Schluss 218 Abbildungen 229 Literaturverzeichnis 255 Bildnachweis 27