Evidence of widespread degradation of gene control regions in hominid genomes

Although sequences containing regulatory elements located close to protein-coding genes are often only weakly conserved during evolution, comparisons of rodent genomes have implied that these sequences are subject to some selective constraints. Evolutionary conservation is particularly apparent upstream of coding sequences and in first introns, regions that are enriched for regulatory elements. By comparing the human and chimpanzee genomes, we show here that there is almost no evidence for conservation in these regions in hominids. Furthermore, we show that gene expression is diverging more rapidly in hominids than in murids per unit of neutral sequence divergence. By combining data on polymorphism levels in human noncoding DNA and the corresponding human¿chimpanzee divergence, we show that the proportion of adaptive substitutions in these regions in hominids is very low. It therefore seems likely that the lack of conservation and increased rate of gene expression divergence are caused by a reduction in the effectiveness of natural selection against deleterious mutations because of the low effective population sizes of hominids. This has resulted in the accumulation of a large number of deleterious mutations in sequences containing gene control elements and hence a widespread degradation of the genome during the evolution of humans and chimpanzees

An LAeq is not an LAeq

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Community response to multiple sound sources : integrating acoustic and contextual approaches in the analysis

Sufficient data refer to the relevant prevalence of sound exposure by mixed traffic sources in many nations. Furthermore, consideration of the potential effects of combined sound exposure is required in legal procedures such as environmental health impact assessments. Nevertheless, current practice still uses single exposure response functions. It is silently assumed that those standard exposure-response curves accommodate also for mixed exposures-although some evidence from experimental and field studies casts doubt on this practice. The ALPNAP-study population (N= 1641) shows sufficient subgroups with combinations of rail-highway, highway-main road and rail-highway-main road sound exposure. In this paper we apply a few suggested approaches of the literature to investigate exposure-response curves and its major determinants in the case of exposure to multiple traffic sources. Highly/moderate annoyance and full scale mean annoyance served as outcome. The results show several limitations of the current approaches. Even facing the inherent methodological limitations ( energy equivalent summation of sound, rating of overall annoyance) the consideration of main contextual factors jointly occurring with the sources (such as vibration, air pollution) or coping activities and judgments of the wider area soundscape increases the variance explanation from up to 8% (bivariate), up to 15% (base adjustments) up to 55% (full contextual model). The added predictors vary significantly, depending on the source combination. (e.g., significant vibration effects with main road/ railway, not highway). Although no significant interactions were found, the observed additive effects are of public health importance. Especially in the case of a three source exposure situation the overall annoyance is already high at lower levels and the contribution of the acoustic indicators is small compared with the non-acoustic and contextual predictors. Noise mapping needs to go down to levels of 40 dBA, Lden to ensure the protection of quiet areas and prohibit the silent " filling up" of these areas with new sound sources. Eventually, to better predict the annoyance in the exposure range between 40 and 60 dBA and support the protection of quiet areas in city and rural areas in planning sound indicators need to be oriented at the noticeability of sound and consider other traffic related by-products (air quality, vibration, coping strain) in future studies and environmental impact assessments

Cardiovascular effects of environmental noise: research in Austria

Cardiovascular effects of noise rank second in terms of disability-adjusted life year (DALYs) after annoyance. Although research during the past decade has consolidated the available data base, the most recent meta-analysis still shows wide confidence intervals - indicating imprecise information for public health risk assessment. The alpine area of Tyrol in the Austrian part of the Alps has experienced a massive increase in car and heavy goods traffic (road and rail) during the last 35 years. Over the past 25 years small-, middle-, and large-sized epidemiological health surveys have been conducted - mostly within the framework of environmental health impact assessments. By design, these studies have emphasized a contextually driven environmental stress perspective, where the adverse health effects on account of noise are studied in a broader framework of environmental health, susceptibility, and coping. Furthermore, innovative exposure assessment strategies have been implemented. This article reviews the existing knowledge from these studies over time, and presents the exposure-response curves, with and without interaction assessment, based on standardized re-analyses and discusses it in the light of past and current cardiovascular noise effects research. The findings support relevant moderation by age, gender, and family history in nearly all studies and suggest a strong need for consideration of non-linearity in the exposure-response analyses. On the other hand, air pollution has not played a relevant role as a moderator in the noise-hypertension or the noise-angina pectoris relationship. Finally, different noise modeling procedures can introduce variations in the exposure response curves, with substantive consequences for public health risk assessment of noise exposure