Estimation of population exposure to terrestrial gamma rays in Canada.

Based on ground gamma ray spectrometry surveys conducted from 2007 to 2010 in populated areas across Canada (i.e. in southern Canada, excluding the northern territories), and with consideration of the exposure outdoors and indoors in various types of buildings as well as exposure to radionuclides in building materials (assuming most building materials are of local origin), the population-weighted annual effective dose from exposure to terrestrial gamma rays was estimated to be 167 ± 43µSv. Under Canadian-specific average occupancy times, indoor exposures at home contribute 69% of the total annual effective dose, followed by 19% from indoor exposures other than at home, 6.2% from outdoor exposures and 5.8% from exposures inside vehicles. This assessment with measurements in a total of 1057 sites in populated areas across Canada is in general agreement with earlier assessments based on airborne gamma surveys mostly over unpopulated areas of Canada and truck-borne radiometric surveys along paved urban roads in four cities.

Synovial chondromatosis of the distal radio-ulnar joint.

Synovial chondromatosis (SC) is a benign metaplastic proliferation of cartilaginous nodules within the synovial membrane. Primary SC, though a rare monoarticular disease, significantly impacts patients' functional and pain-related outcomes. We outline the case of a 52-year-old man who presented with a large mass on the volar-ulnar aspect of his left wrist. Biopsy and workup revealed SC of the distal radio-ulnar joint. Though most cases of SC can be managed with arthroscopic or intralesional resection of the mass, a subset of extremely aggressive cases of SC may ultimately fail intralesional resection. Patients must be counseled about the possibility of amputation as an ultimate treatment option for the resolution of their pain and symptoms.

Dismissing the goals: A comparison of four goal-dismissive goal-free evaluations.

This article provides a descriptive review of four goal-free evaluations (GFE). GFE is an evaluation model where the evaluator conducts the evaluation without knowledge of or reference to the evaluand's stated goals. The four non-randomly sampled evaluation approaches represent articulated evaluation models in which the evaluators ignore the goals of the intervention or project. Data collection consisted of document analyses supplemented by semi-structured interviews with the models' creators. The findings from these case studies include descriptions of the evaluation models, the models' relationship to GFE, and eight commonalities shared among the four models. The conclusion of this study is that these GFEs are similar to other GFEs described in the literature in that they examine outcomes as reported by the intervention's consumers, focus on collecting qualitative data, and use their evaluations to supplement a larger goal-based evaluation strategy.

A study on the correlation between soil radon potential and average indoor radon potential in Canadian cities.

Exposure to indoor radon is identified as the main source of natural radiation exposure to the population. Since radon in homes originates mainly from soil gas radon, it is of public interest to study the correlation between radon in soil and radon indoors in different geographic locations. From 2007 to 2010, a total of 1070 sites were surveyed for soil gas radon and soil permeability. Among the sites surveyed, 430 sites were in 14 cities where indoor radon information is available from residential radon and thoron surveys conducted in recent years. It is observed that indoor radon potential (percentage of homes above 200 Bq m-3; range from 1.5% to 42%) correlates reasonably well with soil radon potential (SRP: an index proportional to soil gas radon concentration and soil permeability; average SRP ranged from 8 to 26). In five cities where in-situ soil permeability was measured at more than 20 sites, a strong correlation (R2 = 0.68 for linear regression and R2 = 0.81 for non-linear regression) was observed between indoor radon potential and soil radon potential. This summary report shows that soil gas radon measurement is a practical and useful predictor of indoor radon potential in a geographic area, and may be useful for making decisions around prioritizing activities to manage population exposure and future land-use planning.

An overview of radon research in Canada.

Based on new scientific information and broad public consultation, the Government of Canada updated the guideline for exposure to indoor radon and launched a multi-year radon programme in 2007. Major achievements in radon research accomplished in the past 7 y are highlighted here.

Achievements and current activities of the Canadian radon program.

Based on new scientific information and broad public consultation, the Government of Canada updated the guideline for exposure to indoor radon and launched a multi-year radon program in 2007. Major achievements accomplished in the past 3 y and current activities underway are highlighted here.

Dual testing algorithm of BED-CEIA and AxSYM Avidity Index assays performs best in identifying recent HIV infection in a sample of Rwandan sex workers.

BACKGROUND: To assess the performance of BED-CEIA (BED) and AxSYM Avidity Index (Ax-AI) assays in estimating HIV incidence among female sex workers (FSW) in Kigali, Rwanda. METHODOLOGY AND FINDINGS: Eight hundred FSW of unknown HIV status were HIV tested; HIV-positive women had BED and Ax-AI testing at baseline and ≥12 months later to estimate assay false-recent rates (FRR). STARHS-based HIV incidence was estimated using the McWalter/Welte formula, and adjusted with locally derived FRR and CD4 results. HIV incidence and local assay window periods were estimated from a prospective cohort of FSW. At baseline, 190 HIV-positive women were BED and Ax-AI tested; 23 were classified as recent infection (RI). Assay FRR with 95% confidence intervals were: 3.6% (1.2-8.1) (BED); 10.6% (6.1-17.0) (Ax-AI); and 2.1% (0.4-6.1) (BED/Ax-AI combined). After FRR-adjustment, incidence estimates by BED, Ax-AI, and BED/Ax-AI were: 5.5/100 person-years (95% CI 2.2-8.7); 7.7 (3.2-12.3); and 4.4 (1.4-7.3). After CD4-adjustment, BED, Ax-AI, and BED/Ax-AI incidence estimates were: 5.6 (2.6-8.6); 9.7 (5.0-14.4); and 4.7 (2.0-7.5). HIV incidence rates in the first and second 6 months of the cohort were 4.6 (1.6-7.7) and 2.2 (0.1-4.4). CONCLUSIONS: Adjusted incidence estimates by BED/Ax-AI combined were similar to incidence in the first 6 months of the cohort. Furthermore, false-recent rate on the combined BED/Ax-AI algorithm was low and substantially lower than for either assay alone. Improved assay specificity with time since seroconversion suggests that specificity would be higher in population-based testing where more individuals have long-term infection.