Distortion product otoacoustic emissions in schoolchildren: Effects of ear asymmetry, handedness and gender

The present study examined effects of ear asymmetry, handedness, and gender on distortion-product otoacoustic emissions (DPOAEs) obtained from schoolchildren. A total of 1003 children (528 boys and 475 girls), with a mean age of 6.2 years (SD = 0.4, range = 5.2-7.9 years), were tested in a quiet room at their schools using the GSI-60 DPOAE system. A distortion-product (DP)-gram was obtained for each ear, with f2 varying from 1.1 to 6.0 kHz and the ratio of f2/f1 at 1.21. The signal-to-noise ratios (SNRs) (DPOAE amplitude minus the mean noise floor) at the tested frequencies 1.1, 1.5, 1.9, 2.4, 3.0, 3.8, 4.8, and 6.0 kHz were measured. The results revealed a small but significant difference in SNR between ears, with right ears showing a higher mean SNR than left ears at 1.9, 3.0, 3.8, and 6.0 kHz. At these frequencies, the difference in mean SNR between ears was less than 1 dB. A significant gender effect was also found. Girls exhibited a higher SNR than boys at 3.8, 4.8, and 6.0 kHz. The difference in mean SNR, as a result of the gender effect, was about 1 to 2 dB at these frequencies. There was no significant difference in mean SNR between left-handed and right-handed children for all tested frequencies.

Distortion product otoacoustic emissions in children at school entry: A comparison with pure tone screening and tympanometry results

This study examined the test performance of distortion product otoacoustic emissions (DPOAEs) when used as a screening tool in the school setting. A total of 1003 children (mean age 6.2 years, SD = 0.4) were tested with pure-tone screening, tympanometry, and DPOAE assessment. Optimal DPOAE test performance was determined in comparison with pure-tone screening results using clinical decision analysis. The results showed hit rates of 0.86, 0.89, and 0.90, and false alarm rates of 0.52, 0.19, and 0.22 for criterion signal-to-noise ratio (SNR) values of 4, 5, and 11 dB at 1.1, 1.9, and 3.8 kHz respectively. DPOAE test performance was compromised at 1.1 kHz. In view of the different test performance characteristics across the frequencies, the use of a fixed SNR as a pass criterion for all frequencies in DPOAE assessments is not recommended. When compared to pure tone plus tympanometry results, the DPOAEs showed deterioration in test performance, suggesting that the use of DPOAEs alone might miss children with subtle middle ear dysfunction. However, when the results of a test protocol, which incorporates both DPOAEs and tympanometry, were used in comparison with the gold standard of pure-tone screening plus tympanometry, test performance was enhanced. In view of its high performance, the use of a protocol that includes both DPOAEs and tympanometry holds promise as a useful tool in the hearing screening of schoolchildren, including difficult-to-test children.

RE: Does Snus use have a harm reduction effect in Sweden?

Eletter to Tobacco Control in response to an eletter published in the same journal about whether snus (Swedish moist oral snuff) was responsible for a decline in smoking prevalence among men in Sweden.

The prospects for tobacco harm reduction

Tobacco harm reduction (THR) policies aim to reduce the prevalence of tobacco-related harm by encouraging smokers who are unable or unwilling to quit to adopt less harmful ways of obtaining nicotine, such as pharmaceutical nicotine and oral tobacco snuff. Proponents of THR argue that the effects of tobacco control policies have reduced smoking as much as they reasonably can and that we can best reduce tobacco-related harm by encouraging smokers to use these methods, which substantially reduce the health risks of smoking. Critics argue that THR policies will undermine the two traditional tobacco control goals of preventing the uptake of smoking by young people and encouraging smokers to quit. I assess the main arguments and evidence advanced for and against THR.

Assessment of Swedish snus for tobacco harm reduction: technical appendix

This technical appendix details the methods used in an assessment of the potential of snus for tobacco harm reduction using simulation modelling.

Quantum symmetries and the Weyl–Wigner product of group representations

In the usual formulation of quantum mechanics, groups of automorphisms of quantum states have ray representations by unitary and antiunitary operators on complex Hilbert space, in accordance with Wigner's theorem. In the phase-space formulation, they have real, true unitary representations in the space of square-integrable functions on phase space. Each such phase-space representation is a Weyl–Wigner product of the corresponding Hilbert space representation with its contragredient, and these can be recovered by 'factorizing' the Weyl–Wigner product. However, not every real, unitary representation on phase space corresponds to a group of automorphisms, so not every such representation is in the form of a Weyl–Wigner product and can be factorized. The conditions under which this is possible are examined. Examples are presented.

Should the health community promote smokeless tobacco (snus) as a harm reduction measure?

Background to the debate: The tobacco control community is divided on whether or not to inform the public that using oral, smokeless tobacco (Swedish snus) is less hazardous to health than smoking tobacco. Proponents of 'harm reduction' point to the Swedish experience. Snus seems to be widely used as an alternative to cigarettes in Sweden, say these proponents, contributing to the low overall prevalence of smoking and smoking-related disease. Harm reduction proponents thus argue that the health community should actively inform inveterate cigarette smokers of the benefits of switching to snus. However, critics of harm reduction say that snus has its own risks, that no form of tobacco should ever be promoted, and that Sweden’s experience is likely to be specific to that culture and not transferable to other settings. Critics also remain deeply suspicious that the tobacco industry will use snus marketing as a 'gateway' to promote cigarettes. In the interests of promoting debate, the authors (who are collaborators on a research project on the future of tobacco control) have agreed to outline the strongest arguments for and against promoting Swedish snus as a form of harm reduction.

Contingent or structural crisis in British agriculture?

The British agricultural sector is either already in or rapidly approaching some sort of crisis. Two features are particularly significant in the political response to the current situation. First, there is an increasingly neoliberal approach to agricultural policy. Sec end, agricultural policy per se is being subsumed with wider rural policies. In this paper we question the rationality of both these trends, both theoretically through 'new wave regulation theory' and by relating the British situation to the recent experiences of the agricultural sectors in Australia and New Zealand.