Adaptive optical phase estimation using time-symmetric quantum smoothing.

Quantum parameter estimation has many applications, from gravitational wave detection to quantum key distribution. The most commonly used technique for this type of estimation is quantum filtering, using only past observations. We present the first experimental demonstration of quantum smoothing, a time-symmetric technique that uses past and future observations, for quantum parameter estimation. We consider both adaptive and nonadaptive quantum smoothing, and show that both are better than their filtered counterparts. For the problem of estimating a stochastically varying phase shift on a coherent beam, our theory predicts that adaptive quantum smoothing (the best scheme) gives an estimate with a mean-square error up to 2sqrt[2] times smaller than nonadaptive filtering (the standard quantum limit). The experimentally measured improvement is 2.24+/-0.14.

Smoking and drinking habits as risk factors for hearing loss in the elderly: epidemiological study of subjects undergoing routine health checks in Aichi, Japan.

In order to determine the risk factors for hearing loss in the elderly, a total of 496 subjects with bilateral hearing loss and 2807 age-matched persons without hearing disturbance were recruited from the participants in an automated multiphasic health screening examination, and their lifestyle and medical data were analysed. Current smokers showed a significantly increased risk of hearing loss compared with non-smokers (odds ratio after adjustment for sex, age, and potential confounders=2.10 (1.53-2.89)), while heavy drinkers did not show an increased risk compared to non-drinkers. Our findings might provide some clues for the primary prevention of age-related hearing loss.

Morphological architecture and distribution of blood capillaries and elastic fibres in the human skin.

This study was undertaken to clarify the morphological features in the blood capillary and elastic fibre distribution of the human skin in terms of susceptibility to pressure sore development. Skin tissues were obtained from bony areas: the sacrum and ischial tuberosity and non-bony area: the centre of the gluteus maximus of 5 aged subjects post mortem for examination using light and scanning electron microscopy. It was observed that the sacral skin had finger-like papillae and underneath the blood capillary loops were most numerous. In the ischial skin the dermal papillae consisted of a combination of finger-like and trapezoid shapes having moderate density of blood capillaries. In contrast, the dermal papillae in the gluteal skin were almost flat, so that the blood capillaries were scattered. The size of elastic bundles in the papillary layer of the sacral, ischial and gluteal skin ranged from 2 to 3 microns, 5 to 10 microns, and 3 to 5 microns, respectively. The elastic fibres were densely distributed in the ischial skin while less so in the sacral skin.

Does time-shrinking take place in visual temporal patterns?

The duration of a short empty time interval (typically shorter than 300 ms) is often underestimated when it is immediately preceded by a shorter time interval. This illusory underestimation--time-shrinking--had been studied only with auditory temporal patterns. In the present study, we examined whether similar underestimation would take place with visual temporal patterns. It turned out that underestimation of the same kind takes place also in the visual modality. However, a considerable difference between the auditory and the visual modalities appeared. In the auditory modality, it had been shown that the amount of underestimation decreased for preceding time intervals longer than 200 ms. In the present study, the underestimation increased when the preceding time interval varied from 160 to 400 ms. Furthermore, the differences between the two neighbouring intervals which could cause this underestimation had always been in a fixed range in the auditory modality. In the visual modality, the range was broader when the intervals were longer. These results were interpreted in terms of an assimilation process in light of the processing-time hypothesis proposed by Nakajima (1987 Perception 16 485-520) in order to explain an aspect of empty-duration perception.

Morphological characteristics of the dermal papillae in the development of pressure sores.

Mechanisms of skin break down in the development of human pressure sores are still unclear. This study was undertaken to clarify the morphological characteristics of the dermal papillae in the skin associated with pressure sores. Skin tissues were excised from the sacrum of a Japanese subject post mortem, where a superficial pressure sore had developed. Light microscopic and transmission and scanning electron microscopic examinations were performed. It was found that the atrophic, irregular contour and alignment of the dermal papillae were characteristic of the boundary area between healthy and damaged areas. In addition, a relatively dense network of collagen fibres in the papillary layer of the boundary area was observed when compared with the healthy area. These findings suggest that the morphological changes of the papillae observed in the boundary area affect microcirculation, impairing tissue viability by inhibiting nutritive blood supply and by accumulating metabolic byproducts which predispose to tissue damage.

[Auditory brain stem responses in Down's syndrome].

Auditory brain-stem responses (ABR) to click stimuli were recorded from 81 children and 20 young adults of Down's syndrome with normal hearing. Comparisons were made to groups of normal control subjects matched by age and sex. I-V interpeak interval in infants younger than 18 months was significantly shorter, while that in children over 18 months and young adults with Down's syndrome was not shortened, compared with that of each control group. Previous studies have emphasised that, regardless of age, the I-V interpeak interval in Down's syndrome is significantly shorter than in the control group. However our study suggests that cases of Down's syndrome with normal hearing have normal central conduction times after CNS maturation. And the shortened central conduction times in infants of Down's syndrome were not lesser than that of normal adults. Our results suggest that the shortened central conduction time in Down-syndrome infants is associated with earlier neurological maturation in Down's syndrome.

Computed tomographic evaluation of multiple mucocoeles of paranasal sinuses.

There are some cases in which mucocoeles of the paranasal sinuses are multiple and their structures are complicated. When the mucocoeles are multiple, pre-operative evaluation is especially important for correct surgical management. We describe the usefulness of computed tomography for the evaluation of multiple mucocoeles of the paranasal sinuses.