A novel constancy check technique for a well type ionisation chamber using a Sr plane-parallel check source.

Accurate determination of source strength in brachytherapy is vital to achieving safe and effective radiotherapy treatments. The recommended detectors to be used for determining source strength are well type ionisation chambers and it is essential to the process that they retain a stable response to radiation, thus maintaining a valid calibration. A new Standard Imaging Inc.

Stable isotope variation in wool as a means to establish Turkish carpet provenance.

The problem of establishing the provenance of carpets of artistic and historical importance is well known. We have addressed this by investigating whether there is sufficient geographical variation in the stable isotopes in wool (namely C, N and S) between key areas of Turkey to be able to recognize the different regions where carpets were made. Here we report results from modern wool samples taken from the winter growth of sheep in 2003/2004 from 13 carpet-producing sites.

"Islands of Risk": subgroups of adolescents at risk for HIV.

Objective: To use cluster analysis to determine profiles of adolescents at risk for HIV.

Methods: Adolescents 15-21 years old (N = 1153) with a history of unprotected sex were assessed in five domains of risk (unprotected sex, alcohol/marijuana use, other drug use, mental health crises, and arrest/school dropout) as well as demographic, contextual, and behavioral variables.

Results: Cluster analysis revealed separate three-cluster solutions for males and females.