Measuring gravity with milligram levitated masses.

Gravity differs from all other known fundamental forces because it is best described as a curvature of space-time. For that reason, it remains resistant to unifications with quantum theory. Gravitational interaction is fundamentally weak and becomes prominent only at macroscopic scales.

Sociodemographic differences in 10-year time trends of emotional and behavioural problems among adolescents attending secondary schools in Amsterdam, The Netherlands.

Societal change in western societies may impact emotional and behavioural problems of adolescents. Firm epidemiological evidence of changes in emotional and behavioural problems during the last decade is lacking. Insight into secular changes in emotional and behavioural problems among adolescents from various sociodemographic groups is crucial for adequate and targeted policy making.

Mortality trends among migrant groups living in Amsterdam.

Background: The main aim of this paper is to see to what extent mortality patterns between migrants living in the Netherlands converge. This might be an indicator of health and health care acculturation.

Methods: This is an observational study on the basis of standard mortality registration data collected between 1996 and 2007.

Use of the life table to compare mortality in ethnic groups in Amsterdam, the Netherlands.

Background: The life table is a valid and frequently used instrument to compare the mortality of migrant groups. Most analyses are limited to an overview and give only life expectancy; however, further analysis of the life table can give more insight into differences in patterns of mortality between groups.

Methods: A thorough life table analysis was applied to the mortality data of seven ethnic groups by age and gender.

Does a reduction in alcohol use by Dutch high school students relate to higher use of tobacco and cannabis?

Background: Substance use of adolescents was investigated in a region around Amsterdam, the Netherlands, in the period 2005-2009. The study was intended to find out to what extent behaviour related to different substances are interrelated and how trends develop in different subgroups.

Methods: Two cross-sectional surveys were conducted among Dutch students in the second and fourth year of secondary school, aged 13-16 [n = 1,854 in 2005; n = 2,088 in 2009] by making use of an online questionnaire including questions about alcohol consumption, tobacco use (smoking behaviour) and cannabis use.