Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty star-forming galaxies. However, the identification of gravitational lenses is often time-intensive, involving the sifting of large volumes of imaging or spectroscopic data to find few candidates. We used early data from the Herschel Astrophysical Terahertz Large Area Survey to demonstrate that wide-area submillimeter surveys can simply and easily detect strong gravitational lensing events, with close to 100% efficiency.

We present a list of 13 candidate gravitationally lensed submillimeter galaxies (SMGs) from 95 deg 2 of the Herschel Multi-tiered Extragalactic Survey, a surface density of 0.14 ± 0.04 deg −2. The selected sources have 500 μm flux densities (S 500) greater than 100 mJy. Gravitational lensing is confirmed by follow-up observations in 9 of the 13 systems (70%), and the lensing status of the four remaining sources is undetermined. We also present a supplementary sample of 29 (0.31 ± 0.06 deg −2) gravitationally lensed SMG candidates with S 500 = 80-100 mJy, which are expected to contain a higher fraction of interlopers than the primary candidates. The number counts of the candidate lensed galaxies are consistent with a simple statistical model of the lensing rate, which uses a foreground matter distribution, the intrinsic SMG number counts, and an assumed SMG redshift distribution. The model predicts that 32%-74% of our S 500 100 mJy candidates are strongly gravitationally lensed (μ 2), with the brightest sources being the most robust; this is consistent with the observational data. Our statistical model also 1

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Background: Patients with mild to moderate obstructive sleep apnoea (OSA) may be managed with different treatment options. This study compared the effectiveness of three commonly used non-surgical treatment modalities. Methods: Subjects with mild to moderate OSA were randomised to one of three treatment groups for 10 weeks: conservative measures (sleep hygiene) only, continuous positive airways pressure (CPAP) in addition to conservative measures or an oral appliance in addition to conservative measures. All overweight subjects were referred to a weight-reduction class. OSA was assessed by polysomnography. Blood pressure was recorded in the morning and evening in the sleep laboratory. Daytime sleepiness was assessed with the Epworth Sleepiness Scale. Health-related quality of life (HRQOL) was assessed with the 36-Item Short-Form Health Survey (SF-36) and Sleep Apnoea Quality of Life Index (SAQLI). Results: 101 subjects with a mean (SEM) apnoea-hypopnoea index (AHI) of 21.4 (1.1) were randomised to one of the three groups. The severity of sleep-disordered breathing was decreased in the CPAP and oral appliance groups compared with the conservative measures group, and the CPAP group was significantly better than the oral appliance group. Relief from sleepiness was significantly better in the CPAP group. CPAP was also better than the oral appliance or conservative measures in improving the ''bodily pain'' domain, and better than conservative measures in improving the ''physical function'' domain of SF-36. Both CPAP and the oral appliance were more effective than conservative measures in improving the SAQLI, although no difference was detected between the CPAP and oral appliance groups. CPAP and the oral appliance significantly lowered the morning diastolic blood pressure compared with baseline values, but there was no difference in the changes in blood pressure between the groups. There was also a linear relationship between the changes in AHI and body weight. Conclusion: CPAP produced the best improvement in terms of physiological, symptomatic and HRQOL measures, while the oral appliance was slightly less effective. Weight loss, if achieved, resulted in an improvement in sleep parameters, but weight control alone was not uniformly effective.