Snellere test voor ggo’s

Met elk nieuw genetisch gemodificeerd gewas (ggo) dat ergens op een akker verschijnt, wordt het werk van analisten die voedingsmiddelen en diervoeders controleren een beetje ingewikkelder. Op RIKILT werkt Jeroen van Dijk aan een nieuw type test waarmee die analisten efficiënt hun werk kunnen blijven doen

Phase mapping of ultrashort pulses in bimodal photonic structures: A window on local group velocity dispersion

The amplitude and phase evolution of ultrashort pulses in a bimodal waveguide structure has been studied with a time-resolved photon scanning tunneling microscope (PSTM). When waveguide modes overlap in time intriguing phase patterns are observed. Phase singularities, arising from interference between different modes, are normally expected at equidistant intervals determined by the difference in effective index for the two modes. However, in the pulsed experiments the distance between individual singularities is found to change not only within one measurement frame, but even depends strongly on the reference time. To understand this observation it is necessary to take into account that the actual pulses generating the interference signal change shape upon propagation through a dispersive medium. This implies that the spatial distribution of phase singularities contains direct information on local dispersion characteristics. At the same time also the mode profiles, wave vectors, pulse lengths, and group velocities of all excited modes in the waveguide are directly measured. The combination of these parameters with an analytical model for the time-resolved PSTM measurements shows that the unique spatial phase information indeed gives a direct measure for the group velocity dispersion of individual modes. As a result interesting and useful effects, such as pulse compression, pulse spreading, and pulse reshaping become accessible in a local measuremen

Self-efficacy, affectivity and smoking behavior in adolescence

Background: Research on health-related behaviors confirms the contribution of self-efficacy and affective factors to the initiation and continuation of smoking behavior. The aim was to assess the degree to which affectivity contributes to the association between self-efficacy and smoking behavior in adolescence. Methods: A sample of 501 elementary school students (mean age 14.7 +/- 0.9 years, 48.5% males) from the Slovak and Czech Republics filled out the Self-Efficacy Scale, the Positive and Negative Affect Schedule and answered questions about smoking behavior. Results: Logistic regression showed that social self-efficacy increased the likelihood of smoking behavior but only after adding positive and negative affectivity to the model. Adjustment for age and gender as covariates did not change these findings. Conclusion: Results show the need to prepare programs aimed at enhancing appropriate social self-efficacy and especially improving skills to resist the pressures emerging from peers. Adolescents should also learn to handle their negative emotions differently, instead of through smoking behavior

Parental divorce, adolescents' feelings toward parents and drunkenness in adolescents

The aim of this study was to explore the association between parental divorce and adolescent drunkenness and the contribution of adolescents' feelings toward their parents to this association. Cross-sectional data on 3,694 elementary school students from several cities in Slovakia (mean age 14.3, 49.0% males; response rate 93%) were obtained. Respondents completed questionnaires on how often they had been drunk in the previous 4 weeks, whether their parents were divorced and a measure of their feelings toward their parents. Parental divorce was found to have an effect on adolescent drunkenness in the previous month, as were the high rates of negative and low rates of positive feelings toward both parents. The effect of divorce on drunkenness strongly decreased if adjusted for the affect of the adolescent toward the father, but not the mother. Our findings indicate that to keep the father positively involved after divorce might be a protective factor with regard to a higher probability of adolescent drunkenness in divorced families

Australian Veterinary History Record No. 47

Australian Veterinary Associatio

Adding a subjective dimension to an ICF-based disability measure for people with multiple sclerosis: development and use of a measure for perception of disabilities

OBJECTIVE: The subjective dimension of disability, the perception of disability, is a dimension missing from the International Classification of Functioning, Disability and Health (ICF), and from health-related quality of life (HRQOL) instruments. However, it is a highly relevant dimension for clinical practice as perceived disability may identify care needs. We therefore developed a measure for this subjective dimension of disability in multiple sclerosis (MS) and examined the contribution of this dimension to QOL. METHOD: A measure named the Multiple Sclerosis Impact Profile-Disability Perception (MSIP-DP) was developed to reflect a person's perception of disabilities reported using the original MSIP-disability (MSIP-D) items. MS patients (n=530) completed both MSIP sections, the medical outcome study short form questionnaire (SF-36), the World Health Organisation Quality Of Life-BREF (WHOQOL-BREF) and questions concerning disease severity. The contribution of disability perception (DP) to QOL in MS was estimated using hierarchical multiple regression analyses after controlling for MS severity. RESULTS: Confirmative factor analysis confirmed the hypothesised disability perception domains that correspond with the related disability domains in the MSIP. DP scales yielded sufficient reliability. DP explained a unique and substantial part of the variance in QOL, particularly the perception of impairments in mental functions. DISCUSSION: Results indicated that the subjective dimension of functioning and health operationalised in the MSIP-DP is a relevant concept in explaining QOL in MS. In clinical practice psychological interventions addressing a patient's perception of disability, particularly of impairments in mental functioning, may contribute to QOL

When Do Managers Seek Private Equity Backing in Public-to-Private Transactions?

Over the last decade, the going private market has experienced a considerable boom in size and also has become more interesting for private equity investors that are looking to partner with incumbent management. This offers managers the choice to take the firm private themselves in a traditional management buyout or to seek private equity backing. We propose that managers decide for a management buyout without any involvement of private equity in case they are less financially constrained: when their firms are undervalued, have high cash levels, are smaller and less financially visible, and the managers own a large toehold. In contrast, managers invite participation of private equity investors when they cannot complete the deal themselves: in firms that are larger, have less cash and managers own a smaller fraction of the firm. Our analysis on a sample of UK public-to-private transactions completed over the period 1997-2003 provides results that are in line with these predictions

An algorithm for the computation of posterior moments and densities using simple importance sampling

In earlier work (van Dijk, 1984, Chapter 3) one of the authors discussed the use of Monte Carlo integration methods for the computation of the multivariate integrals that are defined in the posterior moments and densities of the parameters of interest of econometric models. In the present paper we describe the computational steps of one Monte Carlo method, which is known in the literature as importance sampling. Further, a set of standard programs is available, which may be used for the implementation of a simple case of importance sampling. The computer programs have been written in FORTRAN 77

Consultancy haalbaarheid Klimrekscherm

Deze haalbaarheidstudie heeft als doel de mogelijkheden van het klimrek systeem in de glastuinbouw in kaart te brengen in een semi-gesloten teelt concept teneinde te komen tot energiebesparing, productieverhoging, betere kwaliteit, betere CO2 benutting en minder uitval ten gevolge van vochtproblemen door een te hoge RV