Adolescent Illicit Drug Use and Subsequent Academic and Psychosocial Adjustment : an Examination of Socially-Mediated Pathways

Background: Questions remain regarding the consequences of illicit drug use on adolescent adjustment and the nature of mechanisms that may explain these consequences. In this study, we examined whether early-onset illicit drug use predicts subsequent academic and psychosocial adjustment and whether associations are socially-mediated by decreased school engagement and increased peer deviancy. Method: 4885 adolescents were followed throughout secondary school. We used regressions to determine whether illicit drug use in grade 7 predicted academic achievement, school dropout, depressive symptoms, and conduct problems in grades 10–11, adjusting for potential confounders. We used path analysis to test whether significant associations were mediated by school engagement and peer deviancy in grade 8. Results: Illicit drug use predicted conduct problems and school dropout, but not academic achievement and depressive symptoms. The association between illicit drug use and conduct problems was fully mediated by increased peer deviancy. The association between illicit drug use and school dropout was partially mediated by increased peer deviancy, but remained mostly direct. No indirect association via decreased school engagement was found. Examination of reverse pathways revealed that conduct problems and academic achievement in grade 7 predicted drug use in grades 10–11. These associations were mediated by peer deviancy and school engagement (conduct problems only). Conclusion: Adolescent illicit drug use influences the risk of school dropout and conduct problems in part by contributing to deviant peer affiliation. Reciprocal social mediation characterizes the association between drug use and conduct problems. A reverse mechanism best explains the association with academic achievement.

Influence of experience and training on dental students’ examination performance regarding panoramic images.

Physician training has greatly benefitted from insights gained in understanding the manner in which experts search medical images for abnormalities. The aims of this study were to compare the search patterns of 30 fourth-year dental students and 15 certified oral and maxillofacial radiologists (OMRs) over panoramic images and to determine the most robust variables for future studies involving image visualization. Eye tracking was used to capture the eye movement patterns of both subject groups when examining 20 panoramic images classified as normal or abnormal. Abnormal images were further subclassified as having an obvious, intermediate, or subtle abnormality. The images were presented in random order to each participant, and data were collected on duration of the participants’ observations and total distance tracked, time to first eye fixation, and total duration and numbers of fixations on and off the area of interest (AOI). The results showed that the OMRs covered greater distances than the dental students (p<0.001) for normal images. For images of pathosis, the OMRs required less total time (p<0.001), made fewer eye fixations (p<0.01) with fewer saccades (p<0.001) than the students, and required less time before making the first fixation on the AOI (p<0.01). Furthermore, the OMRs covered less distance (p<0.001) than the dental students for obvious pathoses. For investigations of images of pathosis, time to first fixation is a robust parameter in predicting ability. For images with different levels of subtlety of pathoses, the number of fixations, total time spent, and numbers of revisits are important parameters to analyze when comparing observer groups with different levels of experience.

(Table, page 13-59), Annotated record of the detailed examination of Mn deposits from Amphitrite Expedition stations

The cores described in this report were taken on AMPHITRITE Expedition in Decenber 1963 - February 1964 by Scripps Institution of Oceanography from, the R/V Argo. A total of 148 cores were recovered and are available at Scripps for sampling and study. The coring sites, all in the tropical central Pacific. The AMPHITRITE cores are here briefly described to identify visually distinct units based on lithology, color, texture, or other characteristic unique to an interval of sediment. For determination of lithology, the slides prepared from samples of the cores were examined microscopically in conjuction with the visual examination.

Annotated record of the detailed examination of Mn deposits in a core from R/V Hakuho Maru Cruise KH-74-4 station

A sediment core obtained from the northeastern Philippine Sea Basin was analyzed for 232Th, 230Th, 226Ra and 210Pb. Three sheets of Ferro-manganese oxide in a matrix of red clay were included in the 73 m core. Although the concentration of 232Th of land origin is normal as compared with that of the usual red clay or of the sediment obtained at the neighboring station, the concentration of radiogenic 230Th is extremely low and does not decrease with increasing depth. The radioactivity of rather soluble 226Ra at the station is not less than that of 230Th in the surface sediment, showing a tendency different from that observed in usual cores. Some enrichment in the comparatively short-lived 210Pb activity relative to 226Ra activity was found in the top sediment and in the first ferro-manganese sheet at the station. If the excess 210Pb in the ferro-manganese sheet is not due to contamination of the surface sediment, lead should migrate through the sheet. These facts suggest that the core has not been accumulating during the past few hundred thousand years or more.

Annotated record of the detailed examination of Mn deposits from the cruise of the SS Amra in the Maldives

In this volume, Agassiz gives a detailed account of the results of the cruise the steamer "Amra" chartered from the British India Steam Navigation Company. The cruise covered the attols of the Maldives archipelago. The deep sea formations are described in detail.

Annotated record of the detailed examination of Mn deposits from the R/V Galathea II Danish Deep Sea Expedition, 1950-1952

The Danish Expedition of the "Galathea II" around the world brought important results concerning the marine organisms in the deep sea. The "Galathea II" showed not only different organisms of the Abyssal but for the first time of the deepest trenches of the western Pacific. Anton Bruun coined the term Hadal for the region below the Abyssal under 6000 m. Although the "Galathea II" aimed to investigate new deep sea regions beside the routes of former expeditions and to widen the horizon of knowledge relating marine organisms the technical equipment and the methodological approach had partly been developed earlier. The expedition of the "Galathea II" is part of a long tradition of cruises such as that of the British "Challenger", the German "Valdivia" and the Swedish "Albatross" and especially the Danish cruises of the "Dana I" and "Dana II" which happened some years before.