University of Jyväskylä

About: University of Jyväskylä is a education organization based out in Jyvaskyla, Finland. It is known for research contribution in the topics: Population & Neutron. The organization has 8066 authors who have published 25168 publications receiving 725033 citations. The organization is also known as: Jyväskylän yliopisto & Kasvatusopillinen korkeakoulu.

Changing environmental influences on substance use across development.

Abstract: In contrast to many phenotypes that have been studied using twin designs, substance use shows considerable evidence of environmental influence. Accordingly, specifying the relevant environments and understanding the nature of their effects is an important research priority. Twin studies also have demonstrated that the importance of genetic and environmental influences varies across development for a variety of behavioral outcomes, including substance use. Here, we report analyses exploring moderating effects associated with parenting and peer characteristics on adolescent smoking and drinking, measured at ages 14 and 17. We find significant evidence of moderating effects associated with two dimensions of parenting (parental monitoring and time spent in activities with parents) on adolescent smoking, measured at two time points across development, but no moderating effects on adolescent drinking. Genetic influences on smoking increased, and common environmental effects decreased, as adolescents reported less parental monitoring and spending more time with their parents. Conversely, we find evidence that adolescent drinking is more strongly influenced by peer characteristics. The importance of genetic predispositions was increased among adolescents who reported more friends who used alcohol. These analyses illustrate the importance of incorporating measured aspects of the environment into genetically informative twin models to begin to understand how specific environments are related to various outcomes. Furthermore, they illustrate the importance of using a developmental perspective to understand how specific influences may vary across different ages, and across different phenotypes.

Test-retest reliability of selected items of Health Behaviour in School-aged Children (HBSC) survey questionnaire in Beijing, China

Abstract: Background: Children’s health and health behaviour are essential for their development and it is important to obtain abundant and accurate information to understand young people’s health and health behaviour. The Health Behaviour in School-aged Children (HBSC) study is among the first large-scale international surveys on adolescent health through self-report questionnaires. So far, more than 40 countries in Europe and North America have been involved in the HBSC study. The purpose of this study is to assess the test-retest reliability of selected items in the Chinese version of the HBSC survey questionnaire in a sample of adolescents in Beijing, China. Methods: A sample of 95 male and female students aged 11 or 15 years old participated in a test and retest with a three weeks interval. Student Identity numbers of respondents were utilized to permit matching of test-retest questionnaires. 23 items concerning physical activity, sedentary behaviour, sleep and substance use were evaluated by using the percentage of response shifts and the single measure Intraclass Correlation Coefficients (ICC) with 95% confidence interval (CI) for all respondents and stratified by gender and age. Items on substance use were only evaluated for school children aged 15 years old. Results: The percentage of no response shift between test and retest varied from 32% for the item on computer use at weekends to 92% for the three items on smoking. Of all the 23 items evaluated, 6 items (26%) showed a moderate reliability, 12 items (52%) displayed a substantial reliability and 4 items (17%) indicated almost perfect reliability. No gender and age group difference of the test-retest reliability was found except for a few items on sedentary behaviour. Conclusions: The overall findings of this study suggest that most selected indicators in the HBSC survey questionnaire have satisfactory test-retest reliability for the students in Beijing. Further test-retest studies in a large and diverse sample, as well as validity studies, should be considered for the future Chinese HBSC study. Background Health behaviour of young people is a global concern. Currently, in China, a large range of problems concerning the health behaviour of the youth is emerging along with changes in lifestyle brought about by rapid economic development and globalization [1,2]. So far, only few national surveys concerning the health behaviour of the Chinese youth have been conducted. In addition to national level research, many studies which investigate a particular health behaviour, or a number of health behaviours and lifestyle traits of young people, have been done by Chinese researchers independently or through a collaborative project with foreign researchers [3-9]. Nevertheless, very few of them can give a comprehensive and comparable portfolio of health behaviour of young Chinese people. Research exploring children’s health behaviours and the factors that influence them are important for the development of effective health education and health promotion programs and policies for young people [10]. Many national and international level studies concerning young people’s health behaviour have been conducted in recent decades. The Health Behaviour in School-aged Children (HBSC) study is among the first large-scale

Observational constraints on inhomogeneous cosmological models without dark energy

Abstract: It has been proposed that the observed dark energy can be explained by the effect of large-scale nonlinear inhomogeneities. In this paper, we discuss how observations constrain cosmological models featuring large voids. We start by considering Copernican models, in which the observer is not occupying a special position and homogeneity is preserved on a very large scale. We show how these models, at least in their current realizations, are constrained to give small, but perhaps not negligible in certain contexts, corrections to the cosmological observables. We then examine non-Copernican models, in which the observer is close to the center of a very large void. These models can give large corrections to the observables which mimic an accelerated Friedmann–Lemaitre–Robertson–Walker model. We carefully discuss the main observables and tests able to exclude them.

Early identification of dyslexia and the use of computer game-based practice to support reading acquisition

Abstract: The validity of early predictive measures of delayed reading acquisition is summarized on the basis of the Jyvaskyla Longitudinal study of Dyslexia (JLD). These results show that children in need of support can be identified years before school age. After a brief review of the literature on computer-based interventions, pilot data is reported on the effects of our computer game ‘Literate’ that has been specially developed for preventive training with children who are at risk of failing to acquire reading skill at a normal rate.