This article presents synthesis curves for the relationship between DNL and percentage highly annoyed for three transportation noise sources. The results are based on all 21 datasets examined by Schultz [J. Acoust. Soc. Am. 64, 377-405 (1978)] and Fidell et al. [J. Acoust. Soc. Am. 89, 221-233 (1991)] for which acceptable DNL and percentage highly annoyed measure could be derived, augmented with 34 datasets. Separate, nonidentical curves were found for aircraft, road traffic, and railway noise. A difference between sources was found using data for all studies combined and for only those studies in which respondents evaluated two sources. The latter outcome strengthens the conclusion that the differences between sources cannot be explained by differences in study methodology.

Summary Sleep duration is an important concept in epidemiological studies. It characterizes a night’s sleep or a person’s sleep pattern, and is associated with numerous health outcomes. In most large studies, sleep duration is assessed with questionnaires or sleep diaries. As an alternative, actigraphy may be used, as it objectively measures sleep parameters and is feasible in large studies. However, actigraphy and sleep diaries may not measure exactly the same phenomenon. Our study aims to determine disagreement between actigraphic and diary estimates of sleep duration, and to investigate possible determinants of this disagreement. This investigation was embedded in the population‐based Rotterdam Study. The study population consisted of 969 community‐dwelling participants aged 57–97 years. Participants wore an actigraph and kept a sleep diary for, on average, six consecutive nights. Both measures were used to determine total sleep time (TST). In 34% of the participants, the estimated TST in the sleep diaries deviated more than 1 h from actigraphically measured TST. The level of disagreement between diary and actigraphic measures decreased with subjective and actigraphic measures of sleep quality, and increased with male gender, poor cognitive function and functional disability. Actigraphically measured poor sleep was often accompanied by longer subjective estimates of TST, whereas subjectively poor sleepers tended to report shorter TST in their diaries than was measured with actigraphy. We recommend, whenever possible, to use multiple measures of sleep duration, to perform analyses with both, and to examine the consistency of the results over assessment methods.

The effect of demographic variables ͑sex, age, education level, occupational status, size of household, homeownership, dependency on the noise source, and use of the noise source͒ and two attitudinal variables ͑noise sensitivity and fear of the noise source͒ on noise annoyance is investigated. It is found that fear and noise sensitivity have a large impact on annoyance ͑DNL equivalent equal to ͓at most͔ 19 and 11 dB, respectively͒. Demographic factors are much less important. Noise annoyance is not related to gender, but age has an effect ͑DNL equivalent equal to 5 dB͒. The effects of the other demographic factors on noise annoyance are ͑very͒ small, i.e., the equivalent DNL difference is equal to 1-2 dB, and, in the case of dependency, 3 dB. The results are based on analyses of the original data from various previous field surveys of response to noise from transportation sources ͑number of cases depending on the variable between 15 000 and 42 000͒.

Both humans and group-living animals associate and behave affiliatively more with some individuals than others. Human friendship has long been acknowledged, and recently scientists studying animal behaviour have started using the term friendship for close social associates in animals. Yet, while biologists describe friends as social tools to enhance fitness, social scientists describe human friendship as unconditional. We investigate whether these different descriptions reflect true differences in human friendship and animal close social associations or are a by-product of different research approaches: namely social scientists focussing on proximate and biologists on ultimate explanations. We first stress the importance of similar measures to determine close social associations, thereafter examine their ultimate benefits and proximate motivations, and discuss the latest findings on the central-neural regulation of social bonds. We conclude that both human friendship and animal close social associations are ultimately beneficial. On the proximate level, motivations for friendship in humans and for close social associations in animals are not necessarily based on benefits and are often unconditional. Moreover, humans share with many animals a similar physiological basis of sociality. Therefore, biologists and social scientist describe the same phenomenon, and the use of the term friendship for animals seems justified.

Surveys have shown that noise from wind turbines is perceived as annoying by a proportion of residents living in their vicinity, apparently at much lower noise levels than those inducing annoyance due to other environmental sources. The aim of the present study was to derive the exposure-response relationship between wind turbine noise exposure in L(den) and the expected percentage annoyed residents and to compare it to previously established relationships for industrial noise and transportation noise. In addition, the influence of several individual and situational factors was assessed. On the basis of available data from two surveys in Sweden (N=341, N=754) and one survey in the Netherlands (N=725), a relationship was derived for annoyance indoors and for annoyance outdoors at the dwelling. In comparison to other sources of environmental noise, annoyance due to wind turbine noise was found at relatively low noise exposure levels. Furthermore, annoyance was lower among residents who received economical benefit from wind turbines and higher among residents for whom the wind turbine was visible from the dwelling. Age and noise sensitivity had similar effects on annoyance to those found in research on annoyance by other sources.

This study establishes functions that specify self-reported sleep disturbance in relation to the exposure to nighttime transportation noise, by reanalyzing pooled data from previous studies. Results are based on data from 28 original datasets obtained from 24 field studies (4 studies collected data regarding 2 sources) including almost 23,000 participants exposed to nighttime levels ranging from 45 to 65 dB. Functions are presented that give the percentage highly sleep disturbed, sleep disturbed, and (at least) a little sleep disturbed people due to aircraft, road traffic, and railway noise in relation to the average nighttime outdoor exposure level at the facade most exposed to the source concerned. These functions show that at the same average nighttime noise-exposure level, aircraft noise is associated with more self-reported sleep disturbance than road traffic, and road traffic noise is associated with more sleep disturbance than railways. The association of noise-induced sleep disturbance with age has an inverse U-shape, with the strongest reaction found between 50 and 56 years of age.

This article integrates findings from the literature and new results regarding noise sensitivity. The new results are based on analyses of 28 combined datasets (N = 23,038), and separate analyses of a large aircraft noise study (N = 10,939). Three topics regarding noise sensitivity are discussed, namely, its relationship with noise exposure, its working mechanism, and the scope of its influence. (1) A previous review found that noise sensitivity has no relationship with noise exposure. The current analyses give consistent results, and show that there is at most a very weak positive relationship. (2) It was observed earlier that noise sensitivity alters the effect of noise exposure on noise annoyance, and does not (only) have an additive effect. The current analyses confirm this, and show that the relation of the annoyance score with the noise exposure is relatively flat for nonsensitives while it is steeper for sensitives. (3) Previous studies showed that noise sensitivity also influences reactions other than noise annoyance. The current analyses of the aircraft noise study extend these results, but also indicate that noise sensitivity has relatively little influence on reactions to nonenvironmental conditions.

An experiment evaluated the impact of two typical features of virtual learning environments on anatomical learning for users of differing visuo-spatial ability. The two features studied are computer-implemented stereopsis (the spatial information that is based on differences in visual patterns projected in both eyes) and interactivity (the possibility to actively and continuously change one's view of computer-mediated objects). Participants of differing visuospatial ability learned about human abdominal organs via anatomical three-dimensional (3D) reconstructions using either a stereoptic study phase (involving stereopsis and interactivity) or using a biocular study phase that involved neither stereopsis nor interactivity. Subsequent tests assessed the acquired knowledge in tasks involving (a) identification of anatomical structures in anatomical 2D cross-sections (i.e. typical Computed Tomography pictures) in an identification task, and (b) localization of these cross-sections in a frontal view of the anatomy in a localization task. The results show that the stereoptic group performed significantly better on both tasks and that participants of low visuo-spatial ability benefited more from the stereoptic study phase than those of high visuo-spatial ability.