The construction of teaching roles at Aalborg university centre, 1970–1980

This paper proposes a historical analysis of the development of teaching roles at Aalborg University Centre in its first 10 years. The research highlights three processes through which the interpretation of the new ‘supervisor’ roles was constructed within the problem-oriented, project-based educational model of AUC. First, the authors show that the institutional framework for teaching roles was deliberately left open to significant interpretation from the various faculties of the university; second, the critical theoretical model that had served as a guideline for the inception of project work in Roskilde failed to make an impact in Aalborg, whereas teachers from AUC were more receptive to constructivist psychology as a theoretical framework for practice; third, through community-building and negotiation within the faculties, different interpretations of teaching roles emerged in the different disciplines. The paper closes with a reflection on the implications of these findings for the more general context of higher education.     

Assessment drives learning: The effect of central exit exams on curricular knowledge and mathematical literacy

In this paper, we use data from the German PISA 2003 sample to study the effects of central exit examinations on student performance and student attitudes. Unlike earlier studies we use (i) a value-added measure to pin down the effect of central exit exams on learning in the last year before the exam and (ii) separate test scores for mathematical literacy and curriculum-based knowledge. The findings indicate that central exit exams improve curriculum-based knowledge but do not affect mathematical literacy. Students, although showing a better performance, are less intrinsically motivated in school.     

Why nonverbal immediacy matters: A motivation explanation

Instructional communication behaviors have been routinely associated with student learning outcomes for the past 40 years; however, the explanations for why these relationships exist remain somewhat controversial. Specifically, the relationship between immediacy and learning outcomes continues to be disputed. This study used Self-Determination Theory to evaluate the utility of students’ need for relatedness and their intrinsic motivation to learn as sequential mediators of the teacher immediacy-student learning relationships. Results of a structural equation model supported the theory’s hypothesis, as relatedness and intrinsic motivation to learn operated in serial to mediate the immediacy-learning relationship. These results indicate Self-Determination Theory is a well-suited framework for explaining the relationship between instructors’ communicative behaviors (e.g., immediacy) and their effects on student outcomes.     

Long-term microfluidic glucose and lactate monitoring in hepatic cell culture

Monitoring cellular bioenergetic pathways provides the basis for a detailed understanding of the physiological state of a cell culture. Therefore, it is widely used as a tool amongst others in the field of in vitro toxicology. The resulting metabolic information allows for performing in vitro toxicology assays for assessing drug-induced toxicity. In this study, we demonstrate the value of a microsystem for the fully automated detection of drug-induced changes in cellular viability by continuous monitoring of the metabolic activity over several days. To this end, glucose consumption and lactate secretion of a hepatic tumor cell line were continuously measured using microfluidically addressed electrochemical sensors. Adapting enzyme-based electrochemical flat-plate sensors, originally designed for human whole-blood samples, to their use with cell culture medium supersedes the common manual and laborious colorimetric assays and off-line operated external measurement systems. The cells were exposed to different concentrations of the mitochondrial inhibitor rotenone and the cellular response was analyzed by detecting changes in the rates of the glucose and lactate metabolism. Thus, the system provides real-time information on drug-induced liver injury in vitro.     

Liver transplantation reverses hypergammaglobulinemia in patients with chronic hepatic failure

Introduction

Sparse data are available about the effect of therapy methods on antibody levels in patients with liver failure. The aim of this study was to determine serum immunoglobulin concentrations in patients with chronic hepatic failure (CHF), acute- (ALF), or acute-on-chronic liver failure (ACLF) and to evaluate the impact of MARS treatment or liver transplantation (LT) on antibody levels.

Materials and methods

We followed ten patients with ALF, twelve with ACLF and 18 with CHF. Eight patients with ALF and seven with ACLF underwent MARS therapy, whereas the rest received LT. 13 healthy volunteers served as controls. Serum antibody concentrations were measured using ELISA-technique.

Results

Median serum levels of IgA, IgG and IgM were significantly increased in patients with CHF compared to ALF or controls (P < 0.02, P < 0.01, and P < 0.01). IgM and IgG concentrations were also significantly elevated in patients with CHF compared to ACLF (IgM, 3.7 vs. 1 g/L, P < 0.001; IgG, 8.7 vs. 3.1 g/L, P = 0.004). Immediately after LT a significant decrease of IgA (6.9 vs. 3.1 g/L, P = 0.004), IgG (8.7 vs. 5.1 g/L, P = 0.02) and IgM (3.7 vs. 1.8 g/L, P = 0.001) was detected in patients with CHF and antibody levels further decreased the days after LT reaching levels comparable to healthy individuals. MARS treatment had no apparent effect on the immunoglobulin profile in patients with ALF or ACLF.

Conclusion

We provide evidence that LT reverses hypergammaglobulinemia in patients suffering from CHF within one day, which could be explained to a reconstituted hepatic antibody clearance, whereas MARS treatment has no immediate effect on immunoglobulin levels.Key words: antibodies, immunoglobulins, liver failure, liver transplantation, artificial liver support system, molecular adsorbent recirculating system     

Dealing With Item Nonresponse in Large‐Scale Cognitive Assessments: The Impact of Missing Data Methods on Estimated Explanatory Relationships

Competence data from low‐stakes educational large‐scale assessment studies allow for evaluating relationships between competencies and other variables. The impact of item‐level nonresponse has not been investigated with regard to statistics that determine the size of these relationships (e.g., correlations, regression coefficients). Classical approaches such as ignoring missing values or treating them as incorrect are currently applied in many large‐scale studies, while recent model‐based approaches that can account for nonignorable nonresponse have been developed. Estimates of item and person parameters have been demonstrated to be biased for classical approaches when missing data are missing not at random (MNAR). In our study, we focus on parameter estimates of the structural model (i.e., the true regression coefficient when regressing competence on an explanatory variable), simulating data according to various missing data mechanisms. We found that model‐based approaches and ignoring missing values performed well in retrieving regression coefficients even when we induced missing data that were MNAR. Treating missing values as incorrect responses can lead to substantial bias. We demonstrate the validity of our approach empirically and discuss the relevance of our results.     

Zum Einfluss von Migration und Schulklassenzugeh?rigkeit auf die übergangsempfehlung für die Sekundarstufe I

Ziel der vorliegenden Studie ist die Kl?rung der Frage, inwieweit sachfremde ethnische Kriterien die übergangsempfehlung für weiterführende Schulen beeinflussen. Bei einer Stichprobe von 620 Schülerinnen und Schülern der vierten Klassenstufe wurden Schulleistungstest- und Fragebogendaten erhoben und diese in Beziehung zu den übergangsempfehlungen gesetzt. Wenn individuelle Schülervoraussetzungen unter Einschluss kognitiver F?higkeiten kontrolliert werden, gibt es keine Best?tigung der Auffassung, dass Kinder mit Migrationshintergrund bei der übergangsempfehlung benachteiligt werden. Auch ein hoher Anteil an Kindern mit nicht-deutscher Familiensprache in der Schulklasse übt keine ungünstigen Effekte auf die Empfehlung der Schulform aus. Hingegen ist ein sachfremder Referenzgruppeneffekt (Big-fish-little-pond-Effekt) nachweisbar: Mit einem h?heren Anteil an Schülerinnen und Schülern in der Klasse, deren Schultestleistungen und kognitive Grundf?higkeiten hoch sind und deren Eltern eine h?here Bildungsorientierung aufweisen, sinkt die relative Chance, statt an eine Hauptschule an eine Realschule oder ein Gymnasium zu wechseln.