This study examined the beliefs and attitudes about sleep among 145 older adults. Ss were either chronic insomniacs (n = 74) or self-defined good sleepers (n = 71). They rated their level of agreement or disagreement (visual analog scale) with 28 statements tapping various beliefs, expectations, and attributions about several sleep-related themes. The results showed that insomniacs endorsed stronger beliefs about the negative consequences of insomnia, expressed more hopelessness about the fear of losing control of their sleep, and more helplessness about its unpredictability. These findings suggest that some beliefs and attitudes about sleep may be instrumental in perpetuating insomnia. The main clinical implication is that these cognitions should be identified and targeted for alteration in the management of late-life insomnia.

No abstract

Broadband acoustic signals were transmitted during November 1994 from a 75-Hz source suspended near the depth of the sound-channel axis to a 700-m long vertical receiving array approximately 3250 km distant in the eastern North Pacific Ocean. The early part of the arrival pattern consists of raylike wave fronts that are resolvable, identifiable, and stable. The later part of the arrival pattern does not contain identifiable raylike arrivals, due to scattering from internal-wave-induced sound-speed fluctuations. The observed ray travel times differ from ray predictions based on the sound-speed field constructed using nearly concurrent temperature and salinity measurements by more than a priori variability estimates, suggesting that the equation used to compute sound speed requires refinement. The range-averaged ocean sound speed can be determined with an uncertainty of about 0.05 m/s from the observed ray travel times together with the time at which the near-axial acoustic reception ends, used as a surrogate for the group delay of adiabatic mode 1. The change in temperature over six days can be estimated with an uncertainty of about 0.006°C. The sensitivity of the travel times to ocean variability is concentrated near the ocean surface and at the corresponding conjugate depths, because all of the resolved ray arrivals have upper turning depths within a few hundred meters of the surface.

During the Acoustic Engineering Test ͑AET͒ of the Acoustic Thermometry of Ocean Climate ͑ATOC͒ program, acoustic signals were transmitted from a broadband source with 75-Hz center frequency to a 700-m-long vertical array of 20 hydrophones at a distance of 3252 km; receptions occurred over a period of six days. Each received pulse showed early identifiable timefronts, followed by about 2 s of highly variable energy. For the identifiable timefronts, observations of travel-time variance, average pulse shape, and the probability density function ͑PDF͒ of intensity are presented, and calculations of internal-wave contributions to those fluctuations are compared to the observations. Individual timefronts have rms travel time fluctuations of 11 to 19 ms, with time scales of less than 2 h. The pulse time spreads are between 0 and 5.3 ms rms, which suggest that internal-wave-induced travel-time biases are of the same magnitude. The PDFs of intensity for individual ray arrivals are compared to log-normal and exponential distributions. The observed PDFs are closer to the log-normal distribution, and variances of log intensity are between (3.1 dB) 2 ͑with a scintillation index of 0.74͒ for late-arriving timefronts and (2.0 dB) 2 ͑with a scintillation index of 0.2͒ for the earliest timefronts. Fluctuations of the pulse termination time of the transmissions are observed to be 22 ms rms. The intensity PDF of nonidentified peaks in the pulse crescendo are closer to a log-normal distribution than an exponential distribution, but a Kolmogorov-Smirnov test rejects both distributions. The variance of the nonidentified peaks is (3.5 dB) 2 and the scintillation index is 0.92. As a group, the observations suggest that the propagation is on the border of the unsaturated and partially saturated regimes. After improving the specification of the ray weighting function, predictions of travel-time variance using the Garrett-Munk ͑GM͒ internal-wave spectrum at one-half the reference energy are in good agreement with the observations, and the one-half GM energy level compares well with XBT data taken along the transmission path. Predictions of pulse spread and wave propagation regime are in strong disagreement with the observations. Pulse time spread estimates are nearly two orders of magnitude too large, and ⌳-⌽ methods for predicting the wave propagation regime predict full saturation.

Measurements (1994-2007) from four cabled-to-shore hydrophone systems located off the North American west coast permit extensive comparisons between "contemporary" low frequency ship traffic noise (25-50 Hz) collected in the past decade to measurements made over 1963-1965 with the same in-water equipment at the same sites. An increase of roughly 10 dB over the band 25-40 Hz at one site has already been reported [Andrew et al., Acoust. Res. Lett. Online 3(2), 65-70 (2002)]. Newly corrected data from the remaining three systems generally corroborate this increase. Simple linear trend lines of the contemporary traffic noise (duration 6 to 12+ years) show that recent levels are slightly increasing, holding steady, or decreasing. These results confirm the prediction by Ross that the rate of increase in traffic noise would be far less at the end of the 20th century compared to that observed in the 1950s and 1960s.