Individual- and area-level SES measures were independently related to obesity, which suggests that both individual and environmental approaches may be required to curtail adolescent obesity.

The composition of ultra-high-energy cosmic rays is measured with the High Resolution Fly's Eye cosmic-ray observatory data using the X max technique. Data were collected in stereo between 1999 November and 2001 September. The data are reconstructed with well-determined geometry. Measurements of the atmospheric transmission are incorporated in the reconstruction. The detector resolution is found to be 30 g cm À2 in X max and 13% in energy. The X max elongation rate between 10 18.0 and 10 19.4 eV is measured to be 54:5 AE 6:5 stat ð Þ AE 4:5 sys ð Þg cm À2 per decade. This is compared with predictions using the QGSJet01 and SIBYLL 2.1 hadronic interaction models for both protons and iron nuclei. CORSIKA-generated extensive air showers are incorporated directly into a detailed detector Monte Carlo program. The elongation rate and the X max distribution widths are consistent with a constant or slowly changing and predominantly light composition. A simple model containing only protons and iron nuclei is compared with QGSJet and SIBYLL. The best agreement between the model and the data is for 80% protons for QGSJet and 60% protons for SIBYLL. Subject headingg s: acceleration of particles -cosmic rays -large-scale structure of universe

ABSTRACT. Objectives. We sought to (1) compare estimates of the prevalence of fighting and weapon carrying among adolescent boys and girls in North American and European countries and (2) assess in adolescents from a subgroup of these countries comparative rates of weapon carrying and characteristics of fighting and injury outcomes, with a determination of the association between these indicators of violence and the occurrence of medically treated injury.Design and Setting. Cross-sectional self-report surveys using 120 questions were obtained from nationally representative samples of 161 082 students in 35 countries. In addition, optional factors were assessed within individual countries: characteristics of fighting (9 countries); characteristics of weapon carrying (7 countries); and medically treated injury (8 countries).Participants. Participants included all consenting students in sampled classrooms (average age: 11-15 years).Measures. The primary measures assessed included involvement in physical fights and the types of people involved; frequency and types of weapon carrying; and frequency and types of medically treated injury.Results. Involvement in fighting varied across countries, ranging from 37% to 69% of the boys and 13% to 32% of the girls. Adolescents most often reported fighting with friends or relatives. Among adolescents reporting fights, fighting with total strangers varied from 16% to 53% of the boys and 5% to 16% of the girls. Involvement in weapon carrying ranged from 10% to 21% of the boys and 2% to 5% of the girls. Among youth reporting weapon carrying, those carrying handguns or other firearms ranged from 7% to 22% of the boys and 3% to 11% of the girls. In nearly all reporting countries, both physical fighting and weapon carrying were significantly associated with elevated risks for medically treated, multiple, and hospitalized injury events. 11 Results from these studies have broadened our knowledge of the global impact that adolescent violence has on public health. Existing international comparisons of youth violence have focused on the frequency of adolescent violence-related behaviors in a small number of countries, 12 comparisons of episodes of school violence and its determinants in Israeli and Arabic student populations, 13 studies of "child soldiers" in countries engaged in civil and international warfare, 14,15 international comparisons of firearmrelated mortality, 3 and, as part of more general international comparisons, examinations of firearm regulations and rates of homicide, 3,16,17 robberies and sexual assaults, 17,18 and suicide. 16 Beyond studies of firearms, international comparisons of rates of youth violence are still lacking, and the magnitude and nature of the adolescent violence problem remains unknown for many countries. Cross-national comparisons of violent behaviors in youth have been problematic, because of the use of nonrepresentative samples in many countries and a lack of uniformity in study designs. ConclusionsPhysical fighting and engagement in weapon carry...

Objectives: To compare estimates of the prevalence of injury among adolescents in 35 countries, and to examine the consistency of associations cross nationally between socioeconomic status then drunkenness and the occurrence of adolescent injury. Design: Cross sectional surveys were obtained from national samples of students in 35 countries. Eight countries asked supplemental questions about injury. Setting: Surveys administered in classrooms. Subjects: Consenting students (n = 146 440; average ages 11-15 years) in sampled classrooms. 37 878 students (eight countries) provided supplemental injury data. Exposure measures: Socioeconomic status (material wealth, poverty) and social risk taking (drunkenness). Outcome measures: Specific types and locations of medically treated injury. Results: By country, reports of medically treated injuries ranged from 33% (1060/3173) to 64% (1811/ 2833) of boys and 23% (740/3172) to 51% (1485/2929) of girls, annually. Sports and recreation were the most common activities associated with injury. High material wealth was positively (OR.1.0; p,0.05) and consistently (6/8 countries) associated with medically treated and sports related injuries. Poverty was positively associated with fighting injuries (6/8 countries). Drunkenness (social risk taking) was positively (p,0.01) and consistently (8/8 countries) associated with medically treated, street, and fighting injuries, but not school and sports related injuries. Conclusion: The high prevalence of adolescent injury confirms its importance as a health problem. Social gradients in risk for adolescent injury were illustrated cross nationally for some but not all types of adolescent injury. These gradients were most evident when the etiologies of specific types of adolescent injury were examined. Prevention initiatives should focus upon the etiologies of specific injury types, as well as risk oriented social contexts.

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