Kieferchirurgische Operationsplanung mit Hilfe von Techniken der virtuellen Realit?t

Zusammenfassung.   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. Eingegangen am 27. April 2000 / Angenommen am 21. Februar 2001     

Psychosocial correlates of bulimic symptoms among NCAA division-I female collegiate gymnasts and swimmers/divers

In this study, we tested Petrie and Greenleaf's (2007) model of bulimic symptoms in two independent samples of female collegiate swimmers/divers and gymnasts. Structural equation modeling revealed support for the model, although it also suggested additional pathways. Specifically, general societal pressures regarding weight and body were related to the internalization of those ideals and, subsequently, to increases in body dissatisfaction. Pressures from the sport environment regarding weight and appearance were associated with more body dissatisfaction and more restrictive eating. Body dissatisfaction was related to more feelings of sadness, anger, and fear among the athletes. Negative affect, body dissatisfaction, and dietary restraint were related directly to bulimic symptoms, accounting for 55-58% of its variance. These results suggest that general sociocultural pressures are influential, but weight and appearance pressures in the sport environment may be even more pervasive and negative for female athletes.     

Students’ Conceptions About ‘Radiation’: Results from an Explorative Interview Study of 9th Grade Students

One basis of good teaching is to know about your students?? preconceptions. Studies about typical ideas that students bring to the science classroom have been and continue to be a major field in science education research. This study aims to explore associations and ideas that students have regarding ??radiation??, a term widely used in various fields and necessary to understand fundamental ideas in science. In an explorative study, the perceptions of 50 high school students were examined using semi-structured interviews. The students were 14?C16?years old and were chosen from 7 different high schools in an urban area in Austria. Following an interview guideline, students were asked about their general associations with the term ??radiation?? as well as about their general understanding of different types of radiation. A qualitative analysis of these interviews following the method of Flick (2009) revealed that the students?? associations were, to a great extent, very different from the scientific use of the term. Several conceptions that could inhibit students?? learning processes could be identified. Consequences for the teaching of the topic ??radiation?? in science lessons, which are based on these preconceptions, are presented in the conclusion.     

A MODERN JEWISH EXPERIMENTAL SCHOOL—IN QUEST OF A SYNTHESIS

The question of teacher recruitment for Jewish schools has been on the Jewish community agenda for decades. I have been a practicing Jewish educator for 33 years and in educational administration for 25 years, and I cannot remember a time when there was an abundance of licensed, qualified teachers for Jewish schools. There were always men and women who were available to teach. Most were partially qualified people with some teaching experience. But the fully qualified teacher, especially the one who was effective and successful in the classroom, was a rarity.     

Towards a learning progression of energy

This article presents an empirical study on an initial learning progression of energy, a concept of central importance to the understanding of science. Learning progressions have been suggested as one vehicle to support the systematic and successful teaching of core science concepts. Ideally, a learning progression will provide teachers with a framework to assess students' level of understanding of a core concept and to guide students towards a more sophisticated level of understanding. Taking existing research as a point of departure, developing a learning progression involves recurring cycles of empirical validation and theoretical refinement. In this article, we report about our efforts in working towards a learning progression of energy. First, we derived an initial learning progression by utilizing existing curriculum, research on students' understanding, and development of students' understanding of energy. Second, we used these sources of guidance to develop a robust measurement instrument, the Energy Concept Assessment (ECA), based on multiple choice questions. Third, we utilized this instrument to assess the understanding of N = 1,856 students from three different grade levels, Grades 6, 8, and 10. Findings provided evidence that students from Grade 6 mostly obtain an understanding of energy forms and energy sources. Students of Grade 8 additionally demonstrate an understanding of energy transfer and transformation, whereas only students of Grade 10, and then only some of these students, achieve a deeper understanding of energy conservation. We discuss the implications of our findings against the background of existing research on students understanding of energy. Finally, further steps in working towards a learning progression of energy are identified. Zusammenfassung: Der vorliegende Artikel beschreibt den ersten Schritt in der Entwicklung und Validierung einer Learning Progression für das Energiekonzept; einem Konzept, das zentral für die Entwicklung eines tiefergehenden Versta¨?ndnisses der Naturwissenschaften ist. Learning Progressions sollen das das systematische und erfolgreiche Unterrichten zentraler naturwissenschaftlicher Konzepte unterstützen. Idealerweise sollen Learning Progressions Lehrkräften eine Rahmen bieten, den Entwicklungsstand ihrer Schülerinnen und Schüler hinsichtlich des Verständnisses zentraler naturwissenschaftlicher Konzepte einzuschätzen und Unterricht so zu gestalten, dass er die Entwicklung eines elaborierten Verständnisses befördert. Die Entwicklung einer Learning Progression beginnt mit der theoretischen Begründung einer vorläufigen Learning Progression, gefolgt von iterativen Zyklen empirischer Validierung und Überarbeitung. In diesem Artikel berichten wir über unsere Arbeiten zur Entwicklung einer Learning Progression für das Energiekonzept. Im Rahmen dieser Arbeiten wurde zunächst ausgehend von vorliegenden Befunden zum Verständnis und der Entwicklung des Verständnisses von Energie eine vorläufige Learning Progression begründet. Im zweiten Schritt wurde auf Grundlage der Learning Progression ein entsprechendes Instrument auf Basis von Multiple‐Choice‐Aufgaben entwickelt – das Energy Concept Assessment (ECA). Im dritten und letzten Schritt wurde das Instrument eingesetzt, um das Verständnis von Energie bei N = 1856 Schülerinnen und Schülern der Jahrgänge 6, 8 und 10 zu erfassen. Die Ergebnisse unserer Untersuchung legen nahe, dass Schülerinnen und Schüler aus Jahrgang 6 im Wesentlichen über ein Verständnis von Energieformen und –quellen verfügen. Schülerinnen und Schüler aus Jahrgang 8 zeigen darüber hinaus ein Verständnis von Energieumwandlung und –transport. Ein Verständnis von Energieerhaltung ist nur von Schülerinnen und Schüler aus Jahrgang 10 und dann auch nur von einem Teil dieser Schülerinnen und Schüler zu erwarten. Vor dem Hintergrund dieser Ergebnisse und der bisherigen Forschung zum Energieverständnis, diskutiert der Artikel weitere Schritte für die die Entwicklung einer Learning Progression für das Energiekonzept. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 50:162–188, 2013     

Modelling energy transfers between systems to support energy knowledge in use

ABSTRACT

School instruction is critical for helping students use energy as a lens for making sense of phenomena, however, students often struggle to see the usefulness of energy analysis for interpreting the world around them. One reason for this may be an over-reliance on the idea of energy forms in introductory energy instruction, which may unintentionally suppress, rather than prompt, insights into how and why phenomena occur. We argue that an approach to energy instruction that emphasizes energy transfers between systems, and does not require the idea of energy forms, provides students with a more consistent and useful set of tools for interpreting phenomena. Such a perspective requires connecting the energy concept to the notion that fields, which mediate interaction-at-a-distance, are a real physical system that can transfer energy – an idea that is rarely presented in middle school science. We outline an instructional approach in which middle school students learn to interpret phenomena by modelling energy transfers between systems of interacting objects and fields. We argue that this approach presents a more physically accurate picture of energy, helps align energy instruction across disciplines, and supports students in seeing the value of energy as a lens for making sense of phenomena.     

Critical Pedagogy’s Problem with Changing Teachers’ Dispositions Towards Critical Teaching

Increasing teachers’ dispositions towards critical teaching is a fundamental goal for critical pedagogy. Because critical educational change cannot occur without teachers’ “buy-in,” developing teachers’ inclination to implement critical teaching into their classrooms is a prerequisite for any successful critical pedagogy focused on change in K-12 schools. However, critical educators too often approach K-12 teachers’ dispositions in ways that are at best unproductive and at worst harmful to critical change efforts. Some critical pedagogy exists that approaches teachers’ knowledge and beliefs in “teacher friendly” ways, but most critical pedagogy suffers from the problem of totality and speaks merely to educators who already hold critical dispositions. In response to this problem, this paper identifies and examines three areas in which critical education scholars can work to better connect with a crucial, yet essentially unaddressed constituency: teachers in neighborhood schools. These three areas are critical pedagogy’s audience, teachers’ professional knowledge, and teachers’ beliefs about what constitutes ‘real schools’ and ‘real teachers.’ The paper ends by suggesting approaches to teachers’ dispositions that do not sacrifice the possible to the ideal, that value practical and eclectic change efforts, and that appreciate teachers’ already existing knowledge and beliefs as a foundational medium for developing critical education.     

Measuring Mathematical Competences of Engineering Students at the Beginning of Their Studies

This article reports about our efforts to determine engineering students' competence in mathematics. Our research is embedded in a larger project, KoM@ING–Modeling and developing competence: Integrated IRT based and qualitative studies with a focus on mathematics and its usage in engineering studies, within the program Modeling and Measuring Competencies in Higher Education (KoKoHS). KoKoHS provides the umbrella organization of several research projects addressing the modeling and measuring of competences at the college level. KoM@ING aims to model the role of engineering students' mathematical competences for their studies from both a quantitative and a qualitative perspective.

Here, we report the development of a large-scale instrument assessing engineering freshmen's competence in mathematics by applying Rasch analysis to determine measures for item difficulties and student abilities. Several analyses were performed to provide insights into the measures' reliability and validity. In particular, to examine cognitive validity, we scrutinized students' think-aloud protocols when solving the items to investigate their problem solving abilities as a proxy for item difficulty. Overall, we found first evidence that our instrument is suitable to assess engineering freshmen's competence in mathematics. This instrument may be helpful to conduct further research and to inform those concerned with college organization and policy.     

Developing Teachers' Leadership Knowledge: Pillars for the “New Reform”

This work describes how teacher education programs can inform teachers' knowledge and practice of leadership. We introduce a leadership typology to illustrate how teachers can lead organizational reform for pedagogical excellence and socially just practices. The model provides teacher educators ways to identify and resolve conflicts generated by imparting innovative pedagogies to teachers who in turn use them in antiquated and inequitable school environments. The model can also be used to develop teachers' professional knowledge of the contexts that mitigate or marginalize their leadership potential. Several examples from current teaching practices in teacher education are used to illustrate how teachers develop leadership knowledge.