Estimation of variance components, heritability and the ridge penalty in high-dimensional generalized linear models

For high-dimensional linear regression models, we review and compare several estimators of variances τ2 and σ2 of the random slopes and errors, respectively. These variances relate directly to ridge regression penalty λ and heritability index h2, often used in genetics. Several estimators of these, either based on cross-validation (CV) or maximum marginal likelihood (MML), are also discussed. The comparisons include several cases of the high-dimensional covariate matrix such as multi-collinear covariates and data-derived ones. Moreover, we study robustness against model misspecifications such as sparse instead of dense effects and non-Gaussian errors. An example on weight gain data with genomic covariates confirms the good performance of MML compared to CV. Several extensions are presented. First, to the high-dimensional linear mixed effects model, with REML as an alternative to MML. Second, to the conjugate Bayesian setting, shown to be a good alternative. Third, and most prominently, to generalized linear models for which we derive a computationally efficient MML estimator by re-writing the marginal likelihood as an n-dimensional integral. For Poisson and Binomial ridge regression, we demonstrate the superior accuracy of the resulting MML estimator of λ as compared to CV. Software is provided to enable reproduction of all results.Gwenaël Leday was supported by the Medical Research Council, grant number MR/M004421

Effectiviteit van ervarend leren op de boerderij

In Noord-Brabant zijn individuele woon-werktrajecten op boerderijen ontwikkeld voor jongeren tussen de 16 en 20 jaar met ernstige problemen. Er is sprake van problemen en ruzie in het gezin, de jongeren gaan niet meer naar school en ze hebben geen goede vrijetijdsinvulling. De jongeren verblijven een half jaar op de boerderij. Daarna volgt nog een nabegeleiding van een half jaar. De resultaten van de door de jongeren ingevulde vragenlijsten laten zien dat het traject met name een positief effect heeft op probleemgedrag en zelfwaardering en in iets mindere mate op het copinggedrag. De positieve veranderingen zijn ook een half jaar na afsluiting van het nabegeleidingstraject nog zichtbaar. Uit de scores van de begeleiders blijkt dat er verbeteringen opgetreden zijn in het contact met het gezin, schooluitval, politiecontact, drugsgebruik, vrijetijdsbesteding, welzijn, gedragsproblemen en zelfvertrouwen

The role of acquaintanceship in the perception of child behaviour problems

The role of acquaintanceship with the child on reports of child behaviour by different informants was examined within the framework of a general theory of personality judgment. Mothers of referred children and group-care workers rated videotaped behaviour samples of a well known and an unknown child in the clinic. Independent observers also rated the videotapes. In line with the acquaintanceship hypothesis, mothers were found to perceive more behaviour problems than independent observers when rating well known children but not unknown children. Contrary to the acquaintanceship hypothesis, however, the group-care workers in our study reported more behaviour problems than the other informants regardless of their acquaintance with the children. The clinical and methodological implications of these findings are discussed

The Implementation of Families First in the Netherlands: A One Year Follow-up [IF: 0.725]

Contains fulltext : 63625.pdf (publisher's version ) (Closed access)This study examined whether the American family preservation program Families First was successfully implemented in the Netherlands. Data were collected on 250 children of 177 families who received Families First. At the start of treatment 78% of the children appeared to have serious behavioral problems, 67% of the parents experienced a high level of parental stress, and 63% of the children went through a substantial number of life events during the year preceding the treatment. On average the treatments had the intended duration (about 4 weeks), intensity (about 10 hours a week) and availability (during working hours as well as in evenings and in weekends), and family workers did adhere to important guidelines of treatment delivery. One year after treatment 76% of the children were still living at home. Moreover, children's behavioral problems, parental stress and the number of life events turned out to be significantly decreased. It was concluded that Families First had reached its intended target group, delivered the treatment as intended, and achieved its intended outcomes, suggesting a successful implementation in the Netherlands

De geneesmiddelenmarkt in observatie

Er wordt veel geld uitgegeven aan medicijnen. In 1985 verstrekten apothekers en huisartsen voor ongeveer f. 3 mrd. (incl. honorarium) aan geneesmiddelen. Deze uitgaven zijn in de periode 1980-1985 fors toegenomen. Bovendien zijn geneesmiddelen in alle EGlanden, uitgezonderd West-Duitsland, aanmerkelijk goedkoper dan in ons land. In dit artikel wordt de Nederlandse geneesmiddelenmarkt onder de loep genomen. De auteurs constateren dat er bij zowel de verstrekkers als de gebruikers van medicijnen onvoldoende prikkels aanwezig zijn tot kostenbeheersing. De auteurs hebben hiervoor een aantal suggesties in petto

Emotions in social information processing and their relations with reactive and proactive aggression in referred aggressive boys

Contains fulltext : 56830.pdf (publisher's version ) (Open Access