Zout gietwater bij kasteelten in West - Nederland

De glastuinbouwbedrijven in West-Nederland hebben van een hoog zoutgehalte van de grond herhaaldelijk veel nadeel ondervonden. Een dertig jaar geleden had hier de verzouting van de kasgronden de volgende oorzaken: zout gietwater; opstijgend grondwater; onoordeelkundig bemesten. Het zoutgehalte van het gietwater vormt ook thans nog een probleem

De samenstelling van de zouten in het oppervlaktewater in het Zuidhollands glasdistrict

Aan de kwaliteit van het water dat in kassen voor de besproeiing van gewassen wordt gebruikt, dienen hoge eisen te worden gesteld. Zo is bij voorbeeld het gebruik van sproeiwater dat verontreinigd is met pathogène organismen, uit hygiënisch oogpunt niet toelaatbaar. Voorts kan verontreiniging met anorganische verbindingen nadelig zijn en wel vanwege een remmende invloed op de plantegroei of vanwege vervuiling van gewassen en kasopstanden. Bepaalde anorganische stoffen, zoals ijzer, kunnen reeds in lage concentratie - enkele milligrammen per liter - het water ongeschikt maken als sproeiwater

The normative development of child and adolescent problem behavior. [IF 3.2]

The aim of this study was to identify normative developmental trajectories of parent-reported problems assessed with the Child Behavior Checklist (CBCL; T. M. Achenbach, 1991) in a representative sample of 2,076 children aged 4 to 18 years from the general population. The trajectories were determined by multilevel growth curve analyses on the CBCL syndromes in a longitudinal multiple birth-cohort sample that was assessed 5 times with 2-year intervals. Most syndromes showed a linear increase or decrease with age or a curvilinear trajectory, except for thought problems. Trajectories for most syndromes differed for boys versus girls, except those for withdrawn, social problems, and thought problems. These normative developmental trajectories provide information against which developmental deviance in childhood and adolescence can be detected

Differential predictive value of parents' and teachers' reports of children's problem behaviors: A longitudinal study

This study investigated the prediction of signs of disturbance in 946 children originally aged 4 to 11 years from the general population across a 6-year period. Parents' and teachers' ratings obtained via the Child Behavior Checklist (CBCL) and Teacher's Report Form (TRF) were tested as predictors of (a) academic problems, (b) school behavior problems, (c) receipt of mental health services, (d) child's need for professional help, (e) suicidal behavior, and (f) police contacts. Total problem scores in the deviant range on the CBCL or TRF were significantly associated with poor outcomes 6 years later. The combination of deviant scores on both the CBCL and TRF was a powerful predictor of poor outcomes with 56% of the girls, and 36% of the boys with total problem scores in the deviant range on both instruments maladjusted 6 years later. The CBCL syndromes Attention Problems and Delinquent Behavior, and the TRF syndromes Delinquent Behavior, Somatic Complaints, and Social Problems significantly predicted poor outcomes. Teachers' reports predicted poor outcomes equally well or even somewhat better than parents' reports. It is important to include teacher information in the diagnostic assessment of children

Pathways of self-reported problem behaviors from adolescence into adulthood

OBJECTIVE: The authors determined the impact of different pathways of psychopathological development on adult outcome in subjects followed from ages 11-18 to ages 21-28. METHOD: Problem behaviors of subjects from a general population sample were assessed through the Youth Self-Report and the Young Adult Self-Report given at four time points (1987, 1989, 1991, and 1997). In addition, DSM-IV diagnoses, information pertaining to signs of maladjustment, and measures of social functioning were obtained at the last assessment. On the basis of the self-report ratings, four contrasting developmental pathways of psychopathology were determined: persistent, decreasing, increasing, and consistently normal. RESULTS: Subjects whose overall level of psychopathology was persistent over time had a higher lifetime prevalence of DSM-IV diagnoses and a poorer general outcome in adulthood than did subjects whose level of psychopathology increased. Subjects whose level of psychopathology returned to normal after high levels of problems in adolescence were only slightly different in terms of outcome from subjects with consistently normal ratings. CONCLUSIONS: 1) People who showed high levels of problems in early adolescence but whose level of psychopathology diminished by adulthood seemed to be as healthy as people who never attained a serious level of psychopathology. 2) An ongoing devious pathway into adulthood had negative effects on many domains of functioning. These two findings are both powerful arguments for early intervention in adolescence

A comparison between rate-and-state friction and microphysical models, based on numerical simulations of fault slip

Rate-and-state friction (RSF) is commonly used for the characterisation of laboratory friction experiments, such as velocity-step tests. However, the RSF framework provides little physical basis for the extrapolation of these results to the scales and conditions of natural fault systems, and so open questions remain regarding the applicability of the experimentally obtained RSF parameters for predicting seismic cycle transients. As an alternative to classical RSF, microphysics-based models offer means for interpreting laboratory and field observations, but are generally over-simplified with respect to heterogeneous natural systems. In order to bridge the temporal and spatial gap between the laboratory and nature, we have implemented existing microphysical model formulations into an earthquake cycle simulator. Through this numerical framework, we make a direct comparison between simulations exhibiting RSF-controlled fault rheology, and simulations in which the fault rheology is dictated by the microphysical model. Even though the input parameters for the RSF simulation are directly derived from the microphysical model, the microphysics-based simulations produce significantly smaller seismic event sizes than the RSF-based simulation, and suggest a more stable fault slip behaviour. Our results reveal fundamental limitations in using classical rate-and-state friction for the extrapolation of laboratory results. The microphysics-based approach offers a more complete framework in this respect, and may be used for a more detailed study of the seismic cycle in relation to material properties and fault zone pressure-temperature conditions