Kieferchirurgische Operationsplanung mit Hilfe von Techniken der virtuellen Realit?t

Für ein vollst?ndig computergestütztes Planungssystem zum Zwecke der kieferchirurgischen Operationsplanung ist die Bereitstellung von virtuellen Werkzeugen für den Chirurgen eine grundlegende Voraussetzung. Ausgehend von den Volumendaten mit Sch?del- und Kieferknochen des Patienten erm?glicht ein einfaches Interface unter Verwendung einer geeigneten Visualisierung und haptischer Eingabeger?te die interaktive Definition und Manipulation einzelner virtueller Knochensegmente. Wir haben moderne kraftrückgekoppelte Ger?te aus dem Niedrigpreisbereich eingebunden und auf ihre F?higkeit untersucht, das dreidimensionale Verst?ndnis im Planungsproze?durch Anlehnung an die Vorg?nge bei der chirurgischen Prozedur zu erh?hen. Durch diese Eingabeger?te ist es m?glich, die Knochensegmentierung für eine Osteotomie des Unterkiefers intuitiver und schneller durchzuführen. Die definierten Teilvolumina ergeben zusammen mit ihrer r?umlichen Neuanordnung auf Grundlage einer kephalometrischen Analyse einen Operationsplan. Nach erfolgter Planung werden die Planungsergebnisse in den Operationssaal übertragen. Die intraoperativen Techniken beinhalten die Visualisierung der Planungsergebnisse, die Steuerung der Anwendung über Sprache und die Bestimmung der Patientenposition mittels eines elektromagnetischen 3D-Trackingsystems.     

Results of an empirical study into gender differences in attitudes towards mathematics

Differences in attitude towards mathematics between boys and girls were evaluated in an empirical study carried out in (west)German secondary schools during 1989 on a group of 748 students aged 14–19. The main focus of the study was to ascertain whether the results from previous studies of the last decade, which reported significant differences between boys' and girls' attitudes to mathematics, were still valid.This study shows there are still significant gender differences in many areas, such as: interest in mathematics, importance of high attainment in mathematics, willingness to consider entering a career involving mathematics and mathematical activities and themes from the real world which interest the pupils. Despite these still prevailing gender differences, the study nevertheless shows that girls' and boys' views on gender roles and corresponding areas of activities have changed considerably in recent years (note 1).     

IMPROVING MATHEMATICS TEACHER EDUCATION IN GERMANY: EMPIRICAL RESULTS FROM A LONGITUDINAL EVALUATION OF INNOVATIVE PROGRAMS

Innovative programs for restructuring the entry phase of mathematics teacher education programs have been implemented at various German universities within the last few years. This article reports about the design and the results of a longitudinal evaluation study of the effectiveness of two of these programs aiming to improve mathematics teacher education by altering the conditions in university teaching (the so-called Teacher Education and Development Study TEDS-Telekom). The development of prospective teachers’ professional knowledge in academic mathematical content knowledge, knowledge in elementary mathematics from an advanced standpoint, and mathematical pedagogical content knowledge from the innovative programs were compared to traditional university programs. The study points out that the innovative programs only partially succeeded in improving the acquisition of professional knowledge for prospective mathematics teachers.     

Enhancing research collaborations: Three key management challenges

This conceptual paper explores three areas of research collaboration: (a) effectively harnessing differences, (b) setting defensible boundaries and (c) gaining legitimate authorization. The focus is on their potential lessons for individuals leading and managing research collaborations, evaluation of research partnerships and areas for further investigation. Examples from three partnerships - building the atomic bomb, the Human Genome Project and the World Commission on Dams - are used to highlight key elements of the ideas presented. The paper provides a framework for systematically thinking about integration of different perspectives and other elements essential to any particular collaboration. It also sketches out ideas for (1) managing differences which may destroy partnerships, (2) deciding what the collaboration should encompass, (3) understanding and accommodating forces which may distort what the collaboration is able to achieve, and (4) enlisting necessary supporters while preserving research independence.     

Normative feedback effects on learning a timing task

This study investigated the influence of normative feedback on learning a sequential timing task. In addition to feedback about their performance per trial, two groups of participants received bogus normative feedback about a peer group's average block-to-block improvement after each block of 10 trials. Scores indicated either greater (better group) or less (worse group) than the average improvement, respectively. On the transfer test 1 day later which required producing novel absolute movement times, the better group demonstrated more effective learning than the worse group. These findings add to the mounting evidence that motivational factors affect motor skill learning.     

Self-controlled feedback: does it enhance learning because performers get feedback when they need it?

This paper examines whether self-controlled feedback schedules enhance learning, because they are more tailored to the performers' needs than externally controlled feedback schedules. Participants practiced a sequential timing task. One group of learners (self-control) was provided with feedback whenever they requested it, whereas another group (yoked) had no influence on the feedback schedule. The self-control group showed learning benefits on a delayed transfer test. Questionnaire results revealed that self-control learners asked for feedback primarily after good trials and yoked learners preferred to receive feedback after good trials. Analyses demonstrated that errors were lower on feedback than no-feedback trials for the self-control group but not for the yoked group. Thus, self-control participants appeared to use a strategy for requesting feedback. This might explain learning advantages of self-controlled practice.