Methodological issues associated with longitudinal research: Findings from the Leuven Longitudinal Study on Lifestyle,Fitness and Health (1969 – 2004)     

Lynn Matton  Gaston Beunen  Nathalie Duvigneaud  Katrien Wijndaele  Renaat Philippaerts  Albrecht Claessens 《Journal of sports sciences》2013,31(9):1011-1024

Abstract

Longitudinal studies provide unique opportunities but are also faced with several limitations. The purpose of this study was to document three of these issues (“imperfect” design, evolution of data collection methods, representativeness) by means of the Leuven Longitudinal Study on Lifestyle, Fitness and Health (LLSLFH). The LLSLFH (1969 – 2004) comprises observations on males between 12 and 18 years and at 30, 35, 40, and 47 years, and on females at 16 and 40 years. In the most recent phase of the study, spouses and offspring were also included. The different phases and evolving research questions throughout the LLSLFH required an appropriate adaptation of the research design. The associated evolution of data collection methods largely reflects the changing ideas about physical fitness, body composition, and physical activity, the continuing search for new and better measurement techniques, and the need for adaptations with age. Ongoing study participants are representative in terms of body composition and, except for adolescence in males, also physical activity. No straightforward answer can be given concerning physical fitness. In both sexes, socio-economic status is above average. When informed about the possible “pitfalls” of longitudinal research in advance, several measures could be taken to prevent or limit them as much as possible.  相似文献   

Morphology of polyethylene ski base materials     

Jörg Fischer  Gernot M. Wallner  Alois Pieber 《Journal of sports sciences》2013,31(5):555-562

Abstract

We used high-resolution Raman spectroscopy and differential scanning calorimetry for a comprehensive analysis of carbon black-filled polyethylene ski base grades at processing stages from the raw material to the structured ski base. Based on Raman mapping, we assessed the applicability of an advanced evaluation procedure for amorphous, disordered, and crystalline phase fractions of polyethylene for polyethylene extrusion and sinter grades. For sinter grades, a sufficient segregation between carbon black and polyethylene was confirmed, allowing for a comprehensive Raman spectroscopic morphological analysis. Significant morphological changes in polyethylene due to processing from the raw material to the semi-finished film and to the structured ski base were identified. Throughout the processing chain, we observed a decrease in crystallinity and an increase in the amorphous phase fraction. Although the raw material and the sintered semi-finished film exhibited a different but uniform polyethylene morphology, the morphological changes due to structuring of the ski base are limited to the top surface layer. The highest amorphous phase fractions were detected in the surface of the structured ski bases.  相似文献   

Predictors of discrepancies between informants’ ratings of preschool-aged children's behavior: An examination of ethnicity,child characteristics,and family functioning     

Elizabeth A. Harvey  Candice Fischer  Julie L. Weieneth  Sara D. Hurwitz  Aline G. Sayer 《Early childhood research quarterly》2013

The present study examined predictors of discrepancies between mothers’, fathers’, and teachers’ ratings of 3-year-old children's hyperactivity, attention problems, and aggression. Participants were families of 196 3-year-old children who took part in child and family assessments. Ethnicity was one of the most consistent predictors of discrepancies. African American mothers and fathers were more likely to rate their children's hyperactivity, attention problems, and aggression lower than teachers. In contrast, Latina mothers were more likely to rate their children as more hyperactive and inattentive than teachers. ADHD/ODD diagnoses, parental depression, number of children, and children's pre-academic skills were also predictive of discrepancies for some measures for some informants. These findings provide insight into factors that may contribute to informant discrepancies in ratings of preschool children.  相似文献   

Poverty, Relationship Conflict, and the Regulation of Cortisol in Small and Large Group Contexts at Child Care     

Gabrielle Rappolt-Schlichtmann  John B. Willett  Catherine C. Ayoub  Robert Lindsley  Annmarie C. Hulette  Kurt W. Fischer 《Mind, Brain, and Education》2009,3(3):131-142

The purpose of this research is to explore the dynamics of cortisol regulation in the context of center-based child care by examining the impact of social context (large classroom vs. small group) and relationship quality with caregivers (conflict with mothers and teachers). We extend the research on children's physiologic stress system functioning in center-based child care by focusing on morning cortisol levels among young children living in poverty. While in high-quality center-based child care, children's cortisol levels decreased over the course of the morning—a result that contrasts with findings in previous research with middle-class children, for whom cortisol typically increased over the course of the day while attending center-based child care. Cortisol levels were further reduced when children were moved from a large classroom environment to a small group context. Relationship conflict with mothers and teachers moderated these effects. Children who had high conflict with their mother exhibited cortisol levels that remained higher (decreased less) over the course of the morning, and children who had high conflict with their teacher exhibited cortisol levels that remained higher (decreased less) in response to the small group context. These results indicate that high-quality child care has the potential to support reduced stress among children living in poverty, at least as indicated by adrenocortical activity.  相似文献   

Photoelastic analysis of stress concentration for beams in pure bending with a central hole     

James J. Ryan  Leander J. Fischer 《Journal of The Franklin Institute》1938,225(5):513-526

This paper presents a photoelastic study of the conditions of stress concentration about a hole in a beam subjected to pure bending. Rules for stress determination in beams of this type are suggested.  相似文献   

Stephan Füssel (ed): Gutenberg-Jahrbuch, 2013, volume 88     

Albrecht Classen 《Publishing Research Quarterly》2014,30(1):179-181

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Stephan Füssel (ed): Gutenberg-Jahrbuch,Volume 89     

Albrecht Classen 《Publishing Research Quarterly》2014,30(4):414-415

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Learning communities and scaffolding: three different ways to conceptualizing their relationship     

Frank Fischer 《Instructional Science》2018,46(4):633-637

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Internal and external scripts in computer-supported collaborative inquiry learning   总被引：3，自引：0，他引：3  

Ingo Kollar  Frank Fischer  James D. Slotta 《Learning and Instruction》2007,17(6):708-721

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How do university teachers’ values and beliefs affect their teaching?     

Elisabeth Fischer  Martin Hänze 《教育心理学》2020,40(3):296-317

Abstract

This study investigated university teachers’ characteristics and their influence on teaching practices: Coming from expectancy-value theory, teachers’ personal value of teaching was introduced as a possibly relevant variable and examined along with constructivist and transmissive teaching beliefs as to how they affect various aspects of university teaching. The sample consisted of 79 university teachers, whose data were combined with the teaching assessment of 2552 students enrolled in their courses and of external observers. Multiple regression analyses showed that value of teaching affected observed structuring, student active involvement, and rapport. Transmissive beliefs impacted the observed quality of instruction, and constructivist beliefs were positively related to student-reported clarity of instruction, the stimulation of student involvement, and rapport. Notably, the predictors displayed a data source specific result pattern. As potential reasons for the link between student-reported variables and constructivist beliefs a general factor in the students’ assessment and a survivor bias associated with teachers’ constructivist beliefs are discussed.  相似文献