Noise annoyance in Canada.

The present paper provides the results from two nation-wide telephone surveys conducted in Canada on a representative sample of 5,232 individuals, 15 years of age and older. The goals of this study were to gauge Canadians' annoyance towards environmental noise, identify the source of noise that is viewed as most annoying and quantify annoyance toward this principal noise source according to internationally accepted specifications. The first survey revealed that nearly 8% of Canadians in this age group were either very or extremely bothered, disturbed or annoyed by noise in general and traffic noise was identified as being the most annoying source. A follow-up survey was conducted to further assess Canadians' annoyance towards traffic noise using both a five-item verbal scale and a ten-point numerical scale. It was shown that 6.7% of respondents indicated they were either very or extremely annoyed by traffic noise on the verbal scale. On the numerical scale, where 10 was equivalent to "extremely annoyed" and 0 was equivalent to "not at all annoyed", 5.0% and 9.1% of respondents rated traffic noise as 8 and above and 7 and above, respectively. The national margin of error for these findings is plus or minus 1.9 percentage points, 19 times out of 20. The results are consistent with an approximate value of 7% for the percentage of Canadians, in the age group studied, highly annoyed by road traffic noise (i.e. about 1.8 million people). We found that age, education level and community size had a statistically significant association with noise annoyance ratings in general and annoyance specifically attributed to traffic noise. The use of the International Organization for Standardization/Technical Specification (ISO/TS)-15666 questions for assessing noise annoyance makes it possible to compare our results to other national surveys that have used the same questions.

Marginal discrepancy of screw-retained and cemented metal-ceramic crowns on implants abutments.

This in vitro study quantified the marginal discrepancy of the implant-to-prosthetic-crown interface on nonsubmerged dental implants restored with either a cemented or a screw-retained approach. Metal-ceramic crowns were fabricated for 20 ITI 4.1 x 10 mm solid-screw titanium implants. Ten implants received octa abutments and screw-retained crowns fabricated on premachined gold cylinders. The remaining 10 implants were restored with 5.5-mm solid abutments and metal-ceramic crowns cemented alternately with a glass-ionomer or a zinc phosphate luting agent. Inspection of the implant-crown interface was conducted using light microscopy under x 50 magnification at selected stages in the process of crown fabrication. Statistical analysis revealed a significant difference (P < .001) in the mean marginal fit between screw-retained (8.5 +/- 5.7 microns) and luted implant-supported crowns. This difference was observed both before (54.4 +/- 18.1 microns) and after cementation with glass-ionomer (57.4 +/- 20.2 microns) or zinc phosphate (67.4 +/- 15.9 microns).

Transformational teaching and physical activity: a new paradigm for adolescent health promotion?

Drawing from transformational leadership theory, this research examined adolescent perceptions of transformational teaching within school-based physical education. In Study 1, focus groups with 62 adolescents examined perceptions of physical education teachers' behaviors. In Study 2, follow-up semi-structured interviews were conducted with 18 purposively sampled students. Findings revealed that behaviors within physical education settings can be understood within a conceptual framework that includes transformational teaching. In addition, students who perceived their teachers to utilize transformational behaviors described more adaptive responses. Issues concerning theory development and the application of transformational teaching to physical activity and health promotion settings are considered.

Event-related potential measures of the disruptive effects of trains of auditory stimuli during waking and sleeping states.

Acoustic backup alarms have been reported to particularly disrupt sleep. The present study simulated backup alarms by presenting trains of five consecutive 500 ms duration audible tones, with the time between the onset of each tone being 1 s and the time between trains (offset to onset) between 15 and 20 s. In different conditions, the tones were set at either 80 or 60 dB sound pressure level (SPL). Twelve young adults spent two consecutive nights in the laboratory. Stimuli were presented only on the second night. Measures of traditional sleep architecture (sleep stages) were not affected by the acoustic trains. Event-related potentials were also measured following presentation of the stimuli. In the waking state, the initial 80 dB stimulus elicited a large amplitude N1, peaking at about 100 ms, followed by a positive peak, P3, peaking at about 325 ms. N1 was attenuated following presentation of the 60 dB stimulus. The amplitude of N1 was much reduced following presentation of the subsequent second to fifth stimuli in the train. During non-rapid eye movement (NREM) sleep, the initial 80 dB stimulus elicited a large and later negativity (N350) that was reduced in amplitude for the 60 dB stimulus. A K-Complex (a composite N350 and a much larger N550) was elicited following 35% of the initial 80 dB tones and 12% of the initial 60 dB tones. The amplitude of N550 did not, however, significantly vary as a function of stimulus SPL. During REM sleep, N1 continued to be elicited by the initial louder stimulus, but the later positive wave was not apparent. A late negativity peaking at about 350 ms was, however, apparent. When queried the next morning, subjects rarely indicated that the stimulus presentations disturbed their sleep. This might be because of the absence of the late positivity. The presence of the long latency negativities (N350 and N550) might serve to protect sleep from obtrusive sound during sleep.