Multidimensional item response theory models with general and specific latent traits for ordinal data

The aim of the thesis is to propose a Bayesian estimation through Markov chain Monte Carlo of multidimensional item response theory models for graded responses with complex structures and correlated traits. In particular, this work focuses on the multiunidimensional and the additive underlying latent structures, considering that the first one is widely used and represents a classical approach in multidimensional item response analysis, while the second one is able to reflect the complexity of real interactions between items and respondents. A simulation study is conducted to evaluate the parameter recovery for the proposed models under different conditions (sample size, test and subtest length, number of response categories, and correlation structure). The results show that the parameter recovery is particularly sensitive to the sample size, due to the model complexity and the high number of parameters to be estimated. For a sufficiently large sample size the parameters of the multiunidimensional and additive graded response models are well reproduced. The results are also affected by the trade-off between the number of items constituting the test and the number of item categories. An application of the proposed models on response data collected to investigate Romagna and San Marino residents' perceptions and attitudes towards the tourism industry is also presented.

The effect of arts speech therapy on cerebral oxygenation and low frequency hemodynamic oscillations measured using functional near-infrared spectroscopy

Introduction: As a previous study revealed, arts speech therapy (AST) affects cardiorespiratory interaction [1]. The aim of the present study was to investigate whether AST also has effects on brain oxygenation and hemodynamics measured non-invasively using near-infrared spectroscopy (NIRS). Material and methods: NIRS measurements were performed on 17 subjects (8 men and 9 women, mean age: 35.6 ± 12.7 y) during AST. Each measurement lasted 35 min, comprising 8 min pre-baseline, 10 min recitation and 20 min post-baseline. For each subject, measurements were performed for three different AST recitation tasks (recitation of alliterative, hexameter and prose verse). Relative concentration changes of oxyhemoglobin (Δ[O2Hb]) and deoxyhemoglobin (Δ[HHb]) as well as the tissue oxygenation index (TOI) were measured using a Hamamatsu NIRO300 NIRS device and a sensor placed on the subjects forehead. Movement artifacts were removed using a novel method [2]. Statistical analysis (Wilcoxon test) was applied to the data to investigate (i) if the recitation causes changes in the median values and/or in the Mayer wave power spectral density (MW-PSD, range: 0.07–0.13 Hz) of Δ[O2Hb], Δ[HHb] or TOI, and (ii) if these changes vary between the 3 recitation forms. Results: For all three recitation styles a significant (p < 0.05) decrease in Δ[O2Hb] and TOI was found, indicating a decrease in blood flow. These decreases did not vary significantly between the three styles. MW-PSD increased significantly for Δ[O2Hb] when reciting the hexameter and prose verse, and for Δ[HHb] and TOI when reciting alliterations and hexameter, representing an increase in Mayer waves. The MW-PSD increase for Δ[O2Hb] was significantly larger for the hexameter verse compared to alliterative and prose verse Conclusion: The study showed that AST affects brain hemodynamics (oxygenation, blood flow and Mayer waves). Recitation caused a significant decrease in cerebral blood flow for all recitation styles as well as an increase in Mayer waves, particularly for the hexameter, which may indicate a sympathetic activation. References 1. D. Cysarz, D. von Bonin, H. Lackner, P. Heusser, M. Moser, H. Bettermann. Am J Physiol Heart Circ Physiol, 287 (2) (2004), pp. H579–H587 2. F. Scholkmann, S. Spichtig, T. Muehlemann, M. Wolf. Physiol Meas, 31 (5) (2010), pp. 649–662

Activation of sphingosine kinase 2 is an endogenous protective mechanism in cerebral ischemia

The two ubiquitously expressed sphingosine kinases (SphK) 1 and 2 are key regulators of the sphingolipid signaling pathway. Despite the formation of an identical messenger, i.e. sphingosine 1-phosphate (S1P), they exert strikingly different functions. Particularly, SphK2 is necessary for the phosphorylation of the sphingosine analog fingolimod (FTY720), which is protective in rodent stroke models. Using gene deficient mice lacking either SphK1 or SphK2, we investigated the role of the two lipid kinases in experimental stroke. We performed 2h transient middle cerebral artery occlusion (tMCAO) and analyzed lesion size and neurological function after 24h. Treatment groups received 1mg/kg FTY720. Neutrophil infiltration, microglia activation, mRNA and protein expression of SphK1, SphK2 and the S1P(1) receptor after tMCAO were studied. Genetic deletion of SphK2 but not SphK1 increased ischemic lesion size and worsened neurological function after tMCAO. The protective effect of FTY720 was conserved in SphK1(-/-) mice but not in SphK2(-/-) mice. This suggests that SphK2 activity is an important endogenous protective mechanism in cerebral ischemia and corroborates that the protective effect of FTY720 is mediated via phospho-FTY720.

Acute type A aortic dissection and pregnancy: a population-based study

Pregnancy has been reported to be an independent risk factor for 50% of acute aortic dissections recorded in women younger than 45 years of age. The present epidemiologic study aimed to identify whether this putative association of pregnancy and acute type A dissection could be an artifact of selective reporting.

Outcome of combined stenotic and regurgitant aortic valve disease

This study sought to describe the natural history of combined stenotic and regurgitant aortic valve disease.

Akupunkturpunkte am Ohr bei neugeborenen Drillingen

Die vorliegende Kasuistik beschreibt die gefundenen Ohr-Akupunkturpunkte bei frühgeborenen bichorial triamnioten Drillingen im Alter von 31 Wochen und 2 Tagen. Die Schwangerschaft ist durch IVF entstanden und wurde wegen einer Präeklampsie per Sectio beendet. Die Drillinge wurden am 17. Lebenstag mit dem Svesa Pointselektor 1 070 auf elektrisch aktive Akupunkturpunkte am Ohr untersucht. Je schlechter der klinische Zustand des Neugeborenen, desto mehr Akupunkturpunkte konnten am Ohr gefunden werden. Die identifizierten Reflexzonen/Akupunkturpunkte am Ohr zeigen zum Teil Übereinstimmungen mit der Pathologie im Körper und dem klinischen Zustand des Neugeborenen. Der Schwerpunkt lag bei Organpunkten, was mit dem entsprechenden klinischen Zustand des Organs korrelierte. Psychische Punkte wurden nicht gefunden.

Coronary collateral flow in response to endurance exercise training

BACKGROUND: In humans, it is not known whether physical endurance exercise training promotes coronary collateral growth. The following hypotheses were tested: the expected collateral flow reduction after percutaneous coronary intervention of a stenotic lesion is prevented by endurance exercise training; collateral flow supplied to an angiographically normal coronary artery improves in response to exercise training; there is a direct relationship between the change of fitness after training and the coronary collateral flow change. METHODS AND RESULTS: Forty patients (age 61+/-8 years) underwent a 3-month endurance exercise training program with baseline and follow-up assessments of coronary collateral flow. Patients were divided into an exercise training group (n=24) and a sedentary group (n=16) according to the fact whether they adhered or not to the prescribed exercise program, and whether or not they showed increased endurance (VO2max in ml/min per kg) and performance (W/kg) during follow-up versus baseline bicycle spiroergometry. Collateral flow index (no unit) was obtained using pressure sensor guidewires positioned in the coronary artery undergoing percutaneous coronary intervention and in a normal vessel. In the vessel initially undergoing percutaneous coronary intervention, there was an increase in collateral flow index among exercising but not sedentary patients from 0.155+/-0.081 to 0.204+/-0.056 (P=0.03) and from 0.189+/-0.084 to 0.212+/-0.077 (NS), respectively. In the normal vessel, collateral flow index changes were from 0.176+/-0.075 to 0.227+/-0.070 in the exercise group (P=0.0002), and from 0.219+/-0.103 to 0.238+/-0.086 in the sedentary group (NS). A direct correlation existed between the change in collateral flow index from baseline to follow-up and the respective alteration of VO2max (P=0.007) and Watt (P=0.03). CONCLUSION: A 3-month endurance exercise training program augments coronary collateral supply to normal vessels, and even to previously stenotic arteries having undergone percutaneous coronary intervention before initiating the program. There appears to be a dose-response relation between coronary collateral flow augmentation and exercise capacity gained.

Association of lipopolysaccharide-binding protein and coronary artery disease in men

OBJECTIVES: In this study we tested the hypothesis that lipopolysaccharide-binding protein (LBP) might be able to be used as a biomarker for coronary artery disease (CAD). BACKGROUND: The mechanisms by which the innate immune recognition of pathogens could lead to atherosclerosis remain unclear. Lipopolysaccharide-binding protein is the first protein to encounter lipopolysaccharide and to deliver it to its cellular targets, toll-like receptors; therefore, its presence might be a reliable biomarker that indicates activation of innate immune responses. METHODS: A total of 247 men undergoing elective coronary angiography were studied, and the extent of coronary atherosclerosis was assessed by 2 established scores: "extent score" and "severity score." Levels of LBP, markers of inflammation, and traditional risk factors for CAD were assessed. RESULTS: Serum LBP concentration was significantly increased in 172 patients with angiographically confirmed CAD compared with 75 individuals without coronary atherosclerosis (20.6 +/- 8.7 pg/ml vs. 17.1 +/- 6.0 pg/ml, respectively; p = 0.002). Moreover in multivariable logistic regression analyses, adjusted for established cardiovascular risk factors and markers of systemic inflammation, LBP was a significant and independent predictor of prevalent CAD (p < 0.05 in all models). CONCLUSIONS: Lipopolysaccharide-binding protein might serve as a novel marker for CAD in men. The present results underlie the potential importance of innate immune mechanisms for CAD. Further studies are warranted to bolster the data and to identify pathogenetic links between innate immune system activation and atherosclerosis.

Integriertes Informationsmanagement für Bildungseinrichtungen

Der CampusSource Workshop fand vom 10. bis 12. Oktober 2006 an der Westfälischen Wilhelms Universität (WWU) in Münster statt. Kernpunkte der Veranstaltung waren die Entwicklung einer Engine zur Verknüpfung von e-Learning Anwendungen mit Systemen der HIS GmbH und die Erstellung von Lehr- und Lerninhalten mit dem Ziel der Wiederverwendung. Im zweiten Kapitel sind Vorträge der Veranstaltung im Adobe Flash Format zusammengetragen. Zur Betrachtung der Vorträge ist der Adobe Flash Player, mindestens in der Version 6 erforderlich

Digital Systems for Open Access to Formal and Informal Learning

Today, Digital Systems and Services for Technology Supported Learning and Education are recognized as the key drivers to transform the way that individuals, groups and organizations “learn” and the way to “assess learning” in 21st Century. These transformations influence: Objectives - moving from acquiring new “knowledge” to developing new and relevant “competences”; Methods – moving from “classroom” based teaching to “context-aware” personalized learning; and Assessment – moving from “life-long” degrees and certifications to “on-demand” and “in-context” accreditation of qualifications. Within this context, promoting Open Access to Formal and Informal Learning, is currently a key issue in the public discourse and the global dialogue on Education, including Massive Open Online Courses (MOOCs) and Flipped School Classrooms. This volume on Digital Systems for Open Access to Formal and Informal Learning contributes to the international dialogue between researchers, technologists, practitioners and policy makers in Technology Supported Education and Learning. It addresses emerging issues related with both theory and practice, as well as, methods and technologies that can support Open Access to Formal and Informal Learning. In the twenty chapters contributed by international experts who are actively shaping the future of Educational Technology around the world, topics such as: - The evolution of University Open Courses in Transforming Learning - Supporting Open Access to Teaching and Learning of People with Disabilities - Assessing Student Learning in Online Courses - Digital Game-based Learning for School Education - Open Access to Virtual and Remote Labs for STEM Education - Teachers’ and Schools’ ICT Competence Profiling - Web-Based Education and Innovative Leadership in a K-12 International School Setting are presented. An in-depth blueprint of the promise, potential, and imminent future of the field, Digital Systems for Open Access to Formal and Informal Learning is necessary reading for researchers and practitioners, as well as, undergraduate and postgraduate students, in educational technology.

Against the Tide

In his most recent publication, Against the Tide: Critics of Digitalisation, Otto Peters brings together some of the most formidable and critical voices and compelling perspectives on the potential hazards of digitalization. The viewpoints presented range from personal, anthropological, and pedagogical to more scientific and technical, and arise from multiple disciplines. Peters has long been a respected scholar in the field of distance education, and while Peters’ earlier work has advocated the affordances of digitalization, this latest book is an abrupt shift to the darker side of digitalization. The assembly of critics Peters has gathered come from around the world and different walks of life: journalists, educators, scientists, philosophers, lawyers, mathematicians, and computer scientists, to name a few. Their one shared bond is a deep-seated belief that digitalization will have a profound and lasting impact on humankind – and not only in positive ways. ...