The genetic and environmental effects on school grades in late childhood and adolescence

Eifler EF, Starr A, Riemann R. The genetic and environmental effects on school grades in late childhood and adolescence. PLOS ONE. 2019;14(12): e0225946.As academic achievement can have a major impact on the development of social inequalities we set out to explore how performance differences arise. Using data of the German twin study TwinLife, genetic and environmental effects on school grades in mathematics, German and the grade point average in two age cohorts (11 and 17 years old) were identified. Structural equation modelling on the data of 432 monozygotic and 529 dizygotic twin pairs as well as 317 siblings of the twins showed substantial genetic effects (up to 62%) in both cohorts on all three variables. Next to genetic influences, the twin-specific environment as well as non-shared environmental influences were found to explain the interindividual differences in mathematics and German as well as the grade point average. A cohort effect showing itself in higher heritability in the older cohort was found for mathematics and the grade point average but not for German. Moreover, we compared twins who were assigned to the same classroom to those twins who were assigned to different classrooms and found lower effects of the twin-specific shared environment in the latter group. Our study thereby contributes to the understanding of the etiology of interindividual differences in academic achievement in the numeracy and literacy domain in two age cohorts

The aetiology of educational attainment: A nuclear twin family study into the genetic and environmental influences on school leaving certificates

Eifler EF, Riemann R. The aetiology of educational attainment: A nuclear twin family study into the genetic and environmental influences on school leaving certificates. British Journal of Educational Psychology. 2021: e12478.BACKGROUND: Educational attainment is connected to many important life outcomes, and the previous research has already focused on identifying its genetic and environmental components. However, most of these studies used twin data only and did not incorporate information from other family members. Twin studies typically decompose the phenotypic variance into genetic, shared, and unique environment components. In this study design, the shared environment component encompasses the influence of parents and the shared environments of twins and siblings independent of parents (e.g., teachers, schools, and peers). The classical twin design (CTD) conflates these influences as part of the shared environment. This shortcoming can be overcome using the nuclear twin family design (NTFD), which enables separation of the parental and shared twin/sibling environmental components.; AIMS: The aim of this study was to broaden the understanding of the aetiology of educational attainment using the nuclear twin family design to provide a detailed account of the genetic and environmental effects on the type of school leaving certificate.; SAMPLE: The data of 1,048 monozygotic and 916 dizygotic same-sex twins, their biological parents, and non-twin full biological siblings of the German project TwinLife were used in the nuclear twin family design.; METHODS: Structural equationmodelling (SEM) techniques were used to analyse the variance-covariance patterns of the ordinal outcome variable.; RESULTS: Genetic influences were found to make up around 60% of variance, whilst environmental influences shared by all siblings, educational influences shared by the twins only, and non-shared environmental influences explained the remaining variance in equal amounts. Environmental transmission from parent to offspring was found to be negligible.; CONCLUSION: Through its advanced design, our study extends the previous work enabling more detailed and robust estimations of sources of variance and contributes to a better understanding of the complex aetiology of educational attainment. © 2021 The Authors. British Journal of Educational Psychology published by John Wiley & Sons Ltd on behalf of British Psychological Society

The genetic and environmental effects on school grades in late childhood and adolescence.

As academic achievement can have a major impact on the development of social inequalities we set out to explore how performance differences arise. Using data of the German twin study TwinLife, genetic and environmental effects on school grades in mathematics, German and the grade point average in two age cohorts (11 and 17 years old) were identified. Structural equation modelling on the data of 432 monozygotic and 529 dizygotic twin pairs as well as 317 siblings of the twins showed substantial genetic effects (up to 62%) in both cohorts on all three variables. Next to genetic influences, the twin-specific environment as well as non-shared environmental influences were found to explain the interindividual differences in mathematics and German as well as the grade point average. A cohort effect showing itself in higher heritability in the older cohort was found for mathematics and the grade point average but not for German. Moreover, we compared twins who were assigned to the same classroom to those twins who were assigned to different classrooms and found lower effects of the twin-specific shared environment in the latter group. Our study thereby contributes to the understanding of the etiology of interindividual differences in academic achievement in the numeracy and literacy domain in two age cohorts

ZAŠTO SE LJUDI RAZLIKUJU U MOTIVACIJI KA POSTIGNUĆU? BLIZANAČKA PORODIČNA STUDIJA

Klassen L, Eifler EF, Hufer A, Riemann R. WHY DO PEOPLE DIFFER IN THEIR ACHIEVEMENT MOTIVATION? A NUCLEAR TWIN FAMILY STUDY. PRIMENJENA PSIHOLOGIJA. 2018;11(4):433-450.Although many previous studies have emphasized the role of environmental factors, such as parental home and school environment, on achievement motivation, classical twin studies suggest that both additive genetic influences and non-shared environmental influences explain interindividual differences in achievement motivation. By applying a Nuclear Twin Family Design on the data of the German nationally representative of TwinLife study, we analyzed genetic and environmental influences on achievement motivation in adolescents and young adults. As expected, the results provided evidence for the impact of additive genetic variation, non-additive genetic influences, as well as twin specific shared environmental influences. The largest amount of variance was attributed to non-shared environmental influences, showing the importance of individual experiences in forming differences in achievement motivation. Overall, we suggest a revision of models and theories that explain variation in achievement motivation by differences in familial socialization only

The influence of storage and heat treatment on a magnesium-based implant material: An in vitro and in vivo study

© 2015 Bracht et al. Background: Magnesium alloys are recommended as a potential material for osteosynthesis. It is known that storage-induced property modifications can occur in materials like aluminum. Thus the aim of this study was to analyze the influence of storage durations of up to 48weeks on the biomechanical, structural, and degradation properties of the degradable magnesium alloy LAE442. Methods: Extruded implants (n=104; Ø 2.5mm×25mm) were investigated after storage periods of 0, 12, 24, and 48weeks in three different sub-studies: (I) immediately after the respective storage duration and after an additional (II) 56days of in vitro corrosion in simulated body fluid (SFB), and (III) 48weeks in vivo corrosion in a rabbit model, respectively. In addition, the influence of a T5-heat treatment (206°C for 15h in an argon atmosphere) was tested (n=26; 0week of storage). Evaluation was performed by three-point bending, scanning electron microscopy, radiography, μ-computed tomography, evaluation of the mean grain size, and contrast analysis of precipitations (such as aluminum or lithium). Results: The heat treatment induced a significant reduction in initial stability, and enhanced the corrosion resistance. In vivo experiments showed a good biocompatibility for all implants. During the storage of up to 48weeks, no significant changes occurred in the implant properties. Conclusions: LAE442 implants can be safely used after up to 48weeks of storage

Biocompatibility of MgF \u3c inf\u3e 2 -coated MgNd2 specimens in contact with mucosa of the nasal sinus-A long term study

Up to now, different surgical techniques and stent systems have already been developed and tested for the continuous and adequate ventilation of the frontal sinuses. However, the results achieved still remain poor. Magnesium-based implants have been successfully used in numerous clinical applications. Offering excellent biocompatibility and biodegradability it may be the ideal material for the development of novel implants of the nasal sinus. Here, we present for the first time results on the behaviour of magnesium alloy in a unique environment, i.e. in contact to the nasal mucosa, air and nasal secretion. In a prospective longitudinal study, magnesium fluoride-coated MgNd2 specimens were implanted in the frontal sinuses of 12 minipigs for the investigation of biocompatibility and of the interface between the implant and the mucosa. Endoscopic examinations, histopathological evaluation and EDX measurements were performed regularly up to 180 days. Endoscopic evaluation showed focal mucosal reaction, however, without affecting the patency of the sinus. In addition, no signs of bacterial infections were observed. The EDX analyses showed a marginal but steady increase in the Mg concentration in the mucosa over 180 days. Histological analysis revealed a locally confined moderate mucosal hyperplasia and unspecific inflammatory reaction. Furthermore, we did not find any osteoinductive effects of the magnesium alloy. The results indicate the excellent biocompatibility of the MgNd2 alloy in contact with nasal mucosa and provide a novel material compound and solid proof-of-principle for the development of magnesium-based nasal stents

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The German Twin Family Panel (TwinLife)

Mönkediek B, Lang V, Weigel L, et al. The German Twin Family Panel (TwinLife). Twin Research and Human Genetics. 2019;22(6):540-547.The German Twin Family Panel (TwinLife) is a German longitudinal study of monozygotic and dizygotic same-sex twin pairs and their families that was designed to investigate the development of social inequalities over the life course. The study covers an observation period from approximately 2014 to 2023. The target population of the sample are reared-together twins of four different age cohorts that were born in 2009/2010 (cohort 1), in 2003/2004 (cohort 2), in 1997/1998 (cohort 3) and between 1990 and 1993 (cohort 4). In the first wave, the study included data on 4097 twin families. Families were recruited in all parts of Germany so that the sample comprises the whole range of the educational, occupational and income structure. As of 2019, two face-to-face, at-home interviews and two telephone interviews have been conducted. Data from the first home and telephone interviews are already available free of charge as a scientific use-file from the GESIS data archive. This report aims to provide an overview of the study sample and design as well as constructs that are unique in TwinLife in comparison with previous twin studies — such as an assessment of cognitive abilities or information based on the children’s medical records and report cards. In addition, major findings based on the data already released are displayed, and future directions of the study are presented and discussed