@article{DumontNeumannNagyetal.2013, author = {Dumont, Hanna and Neumann, Marko and Nagy, Gabriel and Becker, Michael and Rose, Norman and Trautwein, Ulrich}, title = {Class composition Effects in non-academic lower secondary school tracks in the state of Baden-W{\"u}rttemberg}, series = {Psychologie in Erziehung und Unterricht : Zeitschrift f{\"u}r Forschung und Praxis}, volume = {60}, journal = {Psychologie in Erziehung und Unterricht : Zeitschrift f{\"u}r Forschung und Praxis}, number = {3}, publisher = {Reinhardt}, address = {M{\"u}nchen}, issn = {0342-183X}, doi = {10.2378/peu2013.art16d}, pages = {198 -- 213}, year = {2013}, abstract = {The study investigates the effects of classroom composition (average ability, achievement, and socio-economic background, proportion of immigrant students) on the development in mathematics achievement, and reading literacy from grade 5 to 6. The study draws on a sample of N=1892 students in vocational track schools (Hauptschule) and intermediate track schools (Realschule) in Baden-Wuerttemberg, Germany. After controlling for school type, and between-school differences in student intake characteristics, none of the compositional characteristics showed a statistically significant effect on achievement development. School track was associated with the development of reading literacy even after controlling for individual differences; however, this relationship lost its statistical significance after the composition of the student body was additionally taken into account.}, language = {de} } @article{ChmielewskiDumontTrautwein2013, author = {Chmielewski, Anna K. and Dumont, Hanna and Trautwein, Ulrich}, title = {Tracking Effects Depend on Tracking Type}, series = {American Educational Research Journal}, volume = {50}, journal = {American Educational Research Journal}, number = {5}, publisher = {Sage}, address = {Thousand Oaks, Calif.}, issn = {0002-8312}, doi = {10.3102/0002831213489843}, pages = {926 -- 957}, year = {2013}, abstract = {The aim of the present study was to examine how different types of tracking— between-school streaming, within-school streaming, and course-by-course tracking—shape students' mathematics self-concept. This was done in an internationally comparative framework using data from the Programme for International Student Assessment (PISA). After controlling for individual and track mean achievement, results indicated that generally for students in course-by-course tracking, high-track students had higher mathematics self-concepts and low-track students had lower mathematics self-concepts. For students in between-school and within-school streaming, the reverse pat- tern was found. These findings suggest a solution to the ongoing debate about the effects of tracking on students' academic self-concept and suggest that the reference groups to which students compare themselves differ according to the type of tracking.}, language = {en} } @article{DumontNeumannMaazetal.2013, author = {Dumont, Hanna and Neumann, Marko and Maaz, Kai and Trautwein, Ulrich}, title = {The effect of student body composition on academic achievement International and National Evidence}, series = {Psychologie in Erziehung und Unterricht : Zeitschrift f{\"u}r Forschung und Praxis}, volume = {60}, journal = {Psychologie in Erziehung und Unterricht : Zeitschrift f{\"u}r Forschung und Praxis}, number = {3}, publisher = {Reinhardt}, address = {M{\"u}nchen}, issn = {0342-183X}, doi = {10.2378/peu2013.art14d}, pages = {163 -- 183}, year = {2013}, abstract = {This paper reviews empirical evidence on the effect of the composition of a student body on academic achievement of students. After defining the term composition effect, methodological aspects regarding the study of composition effects are considered. International and national evidence for the composition of a student body with respect to students' abilities, social, and ethnic background is then presented. Whereas international studies find evidence for social, ethnic, and achievement composition variables, national studies reveal that mean achievement level of a school or class is the most important composition variable in Germany. However, this effect is confounded with school track and social composition, which itself exerts a small incremental effect. Ethnic composition, however, does not seem to play an important role. The paper closes with a presentation of the underlying processes of composition effects and a discussion on how the composition of a student body is considered in school governance practices.}, language = {de} } @article{FeldmannMaduarSanteretal.2016, author = {Feldmann, David and Maduar, Salim R. and Santer, Mark and Lomadze, Nino and Vinogradova, Olga I. and Santer, Svetlana}, title = {Manipulation of small particles at solid liquid interface}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep36443}, pages = {10}, year = {2016}, abstract = {The strong adhesion of sub-micron sized particles to surfaces is a nuisance, both for removing contaminating colloids from surfaces and for conscious manipulation of particles to create and test novel micro/nano-scale assemblies. The obvious idea of using detergents to ease these processes suffers from a lack of control: the action of any conventional surface-modifying agent is immediate and global. With photosensitive azobenzene containing surfactants we overcome these limitations. Such photo-soaps contain optical switches (azobenzene molecules), which upon illumination with light of appropriate wavelength undergo reversible trans-cis photo-isomerization resulting in a subsequent change of the physico-chemical molecular properties. In this work we show that when a spatial gradient in the composition of trans- and cis- isomers is created near a solid-liquid interface, a substantial hydrodynamic flow can be initiated, the spatial extent of which can be set, e.g., by the shape of a laser spot. We propose the concept of light induced diffusioosmosis driving the flow, which can remove, gather or pattern a particle assembly at a solid-liquid interface. In other words, in addition to providing a soap we implement selectivity: particles are mobilized and moved at the time of illumination, and only across the illuminated area.}, language = {en} }