Review of field studies of aircraft noise-induced sleep disturbance

Aircraft noise-induced sleep disturbance (AN-ISD) is potentially among the more serious effects of aircraft noise on people. This literature review of recent field studies of AN-ISD finds that reliable generalization of findings to population-level effects is complicated by individual differences among subjects, methodological and analytic differences among studies, and predictive relationships that account for only a small fraction of the variance in the relationship between noise exposure and sleep disturbance. It is nonetheless apparent in the studied circumstances of residential exposure that sleep disturbance effects of nighttime aircraft noise intrusions are not dramatic on a per-event basis, and that linkages between outdoor aircraft noise exposure and sleep disturbance are tenuous. It is also apparent that AN-ISD occurs more often during later than earlier parts of the night; that indoor sound levels are more closely associated with sleep disturbance than outdoor measures; and that spontaneous awakenings, or awakenings attributable to nonaircraft indoor noises, occur more often than awakenings attributed to aircraft noise. Predictions of sleep disturbance due to aircraft noise should not be based on over-simplifications of the findings of the reviewed studies, and these reports should be treated with caution in developing regulatory policy for aircraft noise.     

Evanescent field devices: a comparison between tapered optical fibres and polished or D-fibres

Abstact This paper examines the operation of tapered optical fibres and polished or D-fibres as evanescent field devices. Both devices operate through the evanescent field outside the fibre interacting with chemicals in the surrounding external medium. The incoming field is absorbed and may be reradiated through fluorescence. The absorption and fluorescence recapture characteristics of both configurations are compared, showing that the tapered fibre device permits a stronger interaction and is therefore more efficient. Furthermore, it is shown that the characteristics of both configurations are sensitive to the refractive index of the external medium.     

A field study of effects of road traffic and railway noise on polysomnographic sleep parameters

The aim of this study was to explore and compare the effect of noise from railway and road traffic on sleep in subjects habitually exposed to nocturnal noise. Forty young and middle aged healthy subjects were studied with polysomnography (PSG) during two consecutive nights in their own bedroom. Noise measurements and recordings were conducted concurrently outside of the bedroom fac?ade as well as inside the bedroom of each participant. Different noise exposure parameters were calculated (L(p,A,eq,night), L(p,A,Fmax,night), and L(AF5,night)) and analyzed in relation to whole-night sleep parameters. The group exposed to railway noise had significantly less Rapid eye movement, (REM) sleep than the group exposed to road traffic noise. A significant association was found between the maximum level (L(p,A,Fmax,night)) of railway noise and time spent in REM sleep. REM sleep was significantly shorter in the group exposed to at least a single railway noise event above 50 dB inside the bedroom. These results, obtained in an ecological valid setting, support previous laboratory findings that railway noise has a stronger impact than road traffic noise on physiological parameters during sleep, and that the maximum noise level is an important predictor of noise effects on sleep assessed by PSG, at least for railway noise.     

Polarization measurements of laboratory VUV light: a first comparison between multilayer polarizers and photoelectron angular distributions

The use of photoelectron angular distributions to determine the linear polarization of VUV light over a wide range of photon energies is demonstrated. Light at wavelengths from 256 to 736 Å, partially polarized by large angle reflections in a toroidal grating monochromator and at a refocus mirror, has been analyzed. The results are validated by comparison measurements at spot wavelengths using multilayer polarizers.     

Road traffic noise - the relationship between noise exposure and noise annoyance in Norway

Exposure-effect relationships between the level of road traffic noise at the most exposed side of a dwelling's façade and the residents' reactions to road traffic noise have been estimated. The relationships are based on five Norwegian socio-acoustic studies featuring 18 study areas from two cities and a total of near 4000 respondents. The survey questionnaires distinguish between noise annoyance experienced right outside the apartment and when indoors. Exposure-effect relationships for all degrees of annoyance are estimated simultaneously from ordinal logit models. These predict road traffic noise annoyance when right outside the apartment and when indoors, respectively, as a function of the road traffic noise level outside the most exposed façade. Separate analyses indicate that Norwegians react stronger to road traffic noise than results from a recent compilation of socio-acoustic surveys would lead one to believe. People having inferior single glazing windows report higher indoor annoyance.     

Relationship between the noise-induced persistent current and the dephasing rate

ac noise in disordered conductors causes both dephasing of the electron wave functions and a dc current around a mesoscopic ring. We demonstrate that the dephasing rate tau(-1)(varphi) in long wires and the dc current , induced by the same noise and averaged over an ensemble of small rings, are connected in a remarkably simple way: tau(varphi) = C(beta)e. Here e is an electron charge, and the constant C(beta) approximately 1 depends on the Dyson symmetry class. The relationship seems to agree reasonably with experiments. This suggests that the two puzzles, anomalously large persistent current and the low-temperature saturation of the dephasing, may have a common solution.     

A non-circadian role for clock-genes in sleep homeostasis:a strain comparison

Background  

We have previously reported that the expression of circadian clock-genes increases in the cerebral cortex after sleep deprivation (SD) and that the sleep rebound following SD is attenuated in mice deficient for one or more clock-genes. We hypothesized that besides generating circadian rhythms, clock-genes also play a role in the homeostatic regulation of sleep. Here we follow the time course of the forebrain changes in the expression of the clock-genes period (per)-1, per2, and of the clock-controlled gene albumin D-binding protein (dbp) during a 6 h SD and subsequent recovery sleep in three inbred strains of mice for which the homeostatic sleep rebound following SD differs. We reasoned that if clock genes are functionally implicated in sleep homeostasis then the SD-induced changes in gene expression should vary according to the genotypic differences in the sleep rebound.     

Friction coefficient and radius of curvature effects upon traffic flow on a curved Road

We investigate the friction coefficient and radius of curvature effects upon traffic flow analytically and numerically. A new model is proposed to describe the motion of vehicles running on a curved road. The stability condition is obtained by the use of control theories. The nonlinear analysis method is taken to derive the modified KdV (Korteweg–de Vries) equation and the kink–antikink solution is obtained near the critical point. Simulations are carried out to verify the double effects upon traffic flow. The flux increases but the stability decreases with an increase of the two parameters. Numerical results are in good agreement with the analytical results.     

Road traffic: A case study of flow and path-dependency in weighted directed networks

How much can we tell about flows through networks just from their topological properties? Whereas flow distributions of river basins, trees or cardiovascular systems come naturally to mind, more complex topologies are not so immediate, especially if the network is large and heterogeneously directed. Our study is motivated by the question of how the distribution of path-dependent trails in directed networks is correlated to the distribution of network flows. As an example we have studied the path-dependencies in closed trails in four metropolitan areas in England and the USA and computed their global and spatial correlations with measured traffic flows. We have found that the heterogeneous distribution of traffic intensity is mirrored by the distribution of agglomerate path-dependency and that high traffic roads are packed along corridors at short-to-medium trail lengths from the ensemble of nodes.     

Road traffic noise exposure in residential complexes built at different times between 1950 and 2000 in Hong Kong

This paper attempts to determine the exposure of the urban population to road traffic noise living in residential complexes built at different times between 1950 and 2000 in Hong Kong. Noise exposure was estimated at the residents’ dwelling, neighborhood and community by noise mapping. The purpose of the study is to find out if the noise exposure levels of these residential complexes have improved as a result of stepped up noise control and reduction efforts. A total of 212 residential complexes built at different times, by the government and private sector in different districts, were selected for noise assessment. The results show that, compared to private housing, public housing estates are generally exposed to less road traffic noise. The study has also found that, over the 50-year period, the dwelling noise exposure levels of the recently built residential complexes are lower than the older ones, showing some improvement over time. This is particularly more noticeable at the high exposure end. There is however only some small differences in noise level between recent and old developments at the community scale both for public and private housing estates.     

Thermodynamic and magnetic properties of HoRh2Si2: A comparison between experiments and calculations in a crystal field model

The origin of two peaks observed in the magnetization and the heat capacity curves of HoRh₂Si₂ is investigated. The thermodynamic and the magnetic properties of this compound are calculated using a Hamiltonian including crystal field and isotropic exchange interaction terms which are comparable in magnitude. Two components (parallel and perpendicular to the c-axis) of the magnetization are evaluated by the molecular field approximation. The two peaks in the magnetization and the heat capacity can be reproduced by choosing appropriate values for crystal field parameters and molecular field constant. The lower transition temperature corresponds to the temperature at which the perpendicular component of the magnetization disappears, and the higher one, to that at which the parallel component of the magnetization disappears.     

Classical theory of the interaction between a spinor field and the gravitational field: First-order field equations

The classical theory of the interaction of a neutral spin-1/2 Dirac field and the gravitational field is studied. For the purely gravitational part of the Lagrangian, written in terms of a vierbein and the local connection coefficient _ab , (regarded as independent field variables), the usual first-order form is adopted. For the Dirac part, however, a different choice is made, in which the covariant derivative of is built with the aid of the vierbein instead of with _ab . This still yields a first-order formalism, but one in which _ab is related to the vierbein in the same way as it would be in the absence of. This ensures that the global connection remains symmetric in andv in the presence of. The way in which the vierbein field equation leads to a familiar Einstein equation with a symmetric and conserved stress tensor on its right side is also analyzed.     

Effect of continuous traffic noise on percentage of deep sleep, waking, and sleep latency

When subjected to alternating quiet nights (32 dB) and noise nights (equivalent levels of 47 dB) a group of 14 subjects showed an average increase in the fraction of deep sleep of about 2.5% resulting from the traffic noise. Another group of 12 subjects whose noise nights were at 60 dB had an average of 4.6% increase in deep sleep during these nights. The number of wakings also increased for both groups but, as was found before, this adapted rapidly with the number of nights. The average latency of sleep onset does not appear to be affected by the traffic noise but individual differences are great and may be of opposite sign. Latency of sleep onset and waking both show appreciable "laboratory effect" which takes longer to disappear than the one or two nights usually assumed.     

Connection between noise-induced symmetry breaking and an information-decoding function for intracellular networks

The biological function of noise-induced symmetry breaking (NISB) is still unclear even though it may potentially occur in noisy intracellular systems. In this work, I demonstrate that information decoding from a noisy signal is a potential biological function of NISB by revealing that NISB naturally emerges from an optimal information-decoding dynamics and that several intracellular networks can be identified with the information-decoding dynamics. I also propose a mean first passage time profile as a way to experimentally identify NISB.     

Noise and sleep at home,a field study on primary and after-effects

The sleep of 20 healthy subjects (10 male, 10 female, 25–63 years) who lived more than one year in streets with high traffic load were recorded during 12 consecutive nights each. Throughout every night EEG, EOG, and sound pressure levels were recorded. In the morning and in the evening as well the subjects completed a short questionnaire and executed a reaction time test. During the experimental phase (five nights) noise level was attenuated by earplugs in 10 subjects, and the other 10 subjects who usually slept with closed windows slept with open windows. Compared to the control nights the 1%-noise level changed by 9 dB(A). In comparison with other variables (age, sex, personality) noise influenced the course of sleep slightly. Small negative effects were found for some physiological, for subjective, and for performance data indicating that there is no (complete) habituation to the usual acoustical environment.     

Annoyance and self-reported sleep disturbances due to structurally radiated noise from railway tunnels

In Norway, the requirement for structure borne noise from tunnels is L_pAFmax = 32 dB inside dwellings. According to the Norwegian Standard 8175 it is expected that up to 20% of the exposed population are disturbed by the noise at this level. However, the scientific basis for this noise limit is poor. The aim of this study was to determine the degree of annoyance and self-reported sleep disturbances as a function of L_pAFmax. In the present study, 521 dwellings exposed to structural sound from railway rock-tunnels were identified. A questionnaire was sent to one randomly selected person above 18 years of age from each dwelling. The results showed that both noise induced annoyance and reported sleep disturbances were significantly related to L_pAFmax. Other factors that increased the annoyance were high pass-by frequency of freight trains per day, and degree of sound insulation of the windows. At L_pAFmax = 32 dB, 20% were slightly or more than slightly annoyed, and 4% were moderately or more than moderately annoyed. According to the pre-existing assumption that up to 20% of the exposed population are disturbed by the noise at this level, the present results give support to the Norwegian noise limit L_pAFmax = 32 dB inside dwellings of structure borne noise from railway tunnels.     

Self-reported sleep disturbances due to railway noise: exposure-response relationships for nighttime equivalent and maximum noise levels

The objective of the present survey was to study self-reported sleep disturbances due to railway noise with respect to nighttime equivalent noise level (L(p,A,eq,night)) and maximum noise level (L(p,A,max)). A sample of 1349 people in and around Oslo in Norway exposed to railway noise was studied in a cross-sectional survey to obtain data on sleep disturbances, sleep problems due to noise, and personal characteristics including noise sensitivity. Individual noise exposure levels were determined outside of the bedroom facade, the most-exposed facade, and inside the respondents' bedrooms. The exposure-response relationships were analyzed by using logistic regression models, controlling for possible modifying factors including the number of noise events (train pass-by frequency). L(p,A,eq,night) and L(p,A,max) were significantly correlated, and the proportion of reported noise-induced sleep problems increased as both L(p,A,eq,night) and L(p,A,max) increased. Noise sensitivity, type of bedroom window, and pass-by frequency were significant factors affecting noise-induced sleep disturbances, in addition to the noise exposure level. Because about half of the study population did not use a bedroom at the most-exposed side of the house, the exposure-response curve obtained by using noise levels for the most-exposed facade underestimated noise-induced sleep disturbance for those who actually have their bedroom at the most-exposed facade.