Expectations regarding development during adolescence: Parental and adolescent perceptions

The aims of this study were (1) to compare the age-related expectations of parents and adolescents concerning the timing of achievement in a number of developmental tasks, (2) to examine whether personal characteristics of the adolescent affect developmental expectations, and (3) to examine whether discrepancies between the adolescents and the parents expectations are related to the amount of parent-adolescent conflict. The sample consisted of 508 families with adolescents (12–18 years old). During a home visit, a battery of questionnaires was administered individually to mothers, fathers, and adolescents. A new 24-item instrument to assess expectations for adolescents mastery of developmental tasks was developed for this study. Analyses showed that when the expectations of adolescents and those of their parents are compared at aggregate level, parents consistently indicate later ages for the achievement of developmental tasks than adolescents. Although parents have later timetables, parents and adolescents have strikingly similar views of the sequence in which achievement of developmental tasks should occur. The adolescents age appears to be the most potent predictor of developmental timetables, followed by gender, pubertal timing, and temperament, respectively. The amount of conflict within the parent-adolescent relationship was associated with differences in developmental expectations. The utility of the new instrument for research and clinical work is discussed.This research was supported by a grant from the Ministry of Health and Culture (PCOJ).     

Plasma,oral fluid and sweat wipe ecstasy concentrations in controlled and real life conditions

In a double-blind placebo controlled study on psychomotor skills important for car driving (Study 1), a 75 mg dose of +/- 3,4-methylenedioxymethamphetamine (MDMA) was administered orally to 12 healthy volunteers who were known to be recreational MDMA-users. Toxicokinetic data were gathered by analysis of blood, urine, oral fluid and sweat wipes collected during the first 5h after administration. Resultant plasma concentrations varied from 21 to 295 ng/ml, with an average peak concentration of 178 ng/ml observed between 2 and 4h after administration. MDA concentrations never exceeded 20 ng/ml. Corresponding MDMA concentrations in oral fluid, as measured with a specific LC-MS/MS method (which required only 50 microl of oral fluid), generally exceeded those in plasma and peaked at an average concentration of 1215 ng/ml. A substantial intra- and inter-subject variability was observed with this matrix, and values ranged from 50 to 6982 ng/ml MDMA. Somewhat surprisingly, even 4-5h after ingestion, the MDMA levels in sweat only averaged 25 ng/wipe. In addition to this controlled study, data were collected from 19 MDMA-users who participated in a driving simulator study (Study 2), comparing sober non-drug conditions with MDMA-only and multiple drug use conditions. In this particular study, urine samples were used for general drug screening and oral fluid was collected as an alternative to blood sampling. Analysis of oral fluid samples by LC-MS/MS revealed an average MDMA/MDEA concentration of 1121 ng/ml in the MDMA-only condition, with large inter-subject variability. This was also the case in the multiple drug condition, where generally, significantly higher concentrations of MDMA, MDEA and/or amphetamine were detected in the oral fluid samples. Urine screening revealed the presence of combinations such as MDMA, MDEA, amph, cannabis, cocaine, LSD and psilocine in the multiple-drug condition.     

Family Structure and Problem Behavior of Adolescents and Young Adults: A Growth-Curve Study

In the present longitudinal 3-wave study of 1274 adolescents and young adults, aged 12–24 at the 1st wave, it is examined whether youngsters from intact versus postdivorce families show long-term differences in internalizing and externalizing problems. Furthermore, possible differences in the development of this problem behavior between offspring from intact and postdivorce families are examined, i.e., possible differences in growth curves of internalizing and externalizing problems are investigated. Longitudinal multilevel analyses reveal long-term differences in internalizing and externalizing problems according to family structure. Adolescents and young adults growing up in postdivorce families display more internalizing and externalizing problem behavior than youngsters of intact families. The development of these 2 types of problem behavior does not differ by gender or family structure. That is, the shape of the growth curves of internalizing and externalizing problem behavior is similar for boys and girls and also for youngsters from intact and postdivorce families. Inge VanderValk is a Postdoc Researcher at the Department of Child and Adolescent Studies, Utrecht University, the Netherlands. She received her Ph.D. in 2004 from Utrecht University. Her major research interests include associations between adolescent adjustment and parental marital quality and parental divorce. Ed Spruijt is an Associate Professor at the University of Utrecht. He received his Ph.D. in 1983 from Utrecht University. His major research interests are the consequences of parental divorce and visitation arrangements on children. Martijn de Goede is an associate Professor at Utrecht University, Department of Methodology and Statistics. He received his Ph.D. in 1988 from Utrecht University. His major research interests are occupational and relational life courses of youngsters. Cora Maas is an Assistent Professor at Utrecht University, Department of Methodology and Statistics. She received her PH.D. in 1992 in Utrecht from Utrecht University. Her major interests are: multilevel analysis (theory and applications). Wim Meeus is full Professor of Adolescent Development at Utrecht University. He received his Ph.D. in 1984 from Utrecht University. His major research interests are personality, identity, and relationships in adolescence.     

An Empirical Study on the Relation Between the Critical Angle for Bullet Ricochet and the Properties of Wood

The properties of a bullet, an object, and the incidence angle determine whether the bullet will penetrate, perforate, or ricochet. In this study, the critical angle for ricochet was established for .32 Auto and 9 mm Luger bullets on Abachi, Southern Yellow Pine, Beech, and Ipe wooden boards. Results show that the critical angle differs depending on caliber and wood type. The critical angle is higher for .32 Auto bullets than for 9 mm Luger bullets and increases with increasing wood density and Janka hardness. The established critical angles for ricochet on the lightest and softest wood (Abachi) are 10.4° and 10.3° for .32 Auto and 9 mm Luger, respectively. For the heaviest and hardest wood (Ipe), the angles were 45.0° and 33.4°, respectively. The combined results on the four tested woods show a strong linear relationship between both the density and the hardness and the critical angle for both calibers.     

The Influence of Wood Grain on the Bullet's Ricochet Behavior

When a bullet ricochets from wood, various parameters will influence its behavior. In this study, the influence of the wood grain on the ricochet angle (β) and deflection angle (γ) is assessed. Series of five .32 Auto bullets were fired at different angles of incidence (α) on boards of six wood types. The results confirm the previously shown effect that the mean β‐angles usually exceed α and increase when α increases. Overall, the maximum mean γ occurs when the angle of wood grain (ζ), in relation to the plane of impact, lies between 30° and 75° but differs per combination of wood and α. The results show the inclination of γ toward the left or right, depending on the bullets left or right rotation while also showing that the direction of ζ can enhance or counteract this effect considerably, especially when α is close to the critical ricochet angle.     

The quantitative methods component in social sciences curricula in view of journal content

What level of quantitative methods (or applied statistical analysis) should graduate students in the social sciences be prepared to master, if they are to be competitive in the job market? In the age of information technology, more data, in survey or other form, about any imaginable topic exist than ever before. Empirical analysis on the basis of more advanced quantitative methods becomes more common. This study takes the perspective that graduate students in the social sciences must be prepared to read a literature that makes extensive use of quantitative methods. To quantify this dimension of the literature, top journals in economics, political science, public administration, and sociology are examined for their quantitative complexity.