•Simulator sickness reduced average speed and steering wheel reversal frequency.•Simulator sickness did not influence standard deviation of lateral position (SDLP).•Higher blood alcohol concentration ...decreased simulator sickness scores.•Simulator sickness may confound and introduce bias in experimental studies.
Simulator sickness is a major obstacle to the use of driving simulators for research, training and driver assessment purposes. The purpose of the present study was to investigate the possible influence of simulator sickness on driving performance measures such as standard deviation of lateral position (SDLP), and the effect of alcohol or repeated simulator exposure on the degree of simulator sickness. Twenty healthy male volunteers underwent three simulated driving trials of 1h’s duration with a curvy rural road scenario, and rated their degree of simulator sickness after each trial. Subjects drove sober and with blood alcohol concentrations (BAC) of approx. 0.5g/L and 0.9g/L in a randomized order. Simulator sickness score (SSS) did not influence the primary outcome measure SDLP. Higher SSS significantly predicted lower average speed and frequency of steering wheel reversals. These effects seemed to be mitigated by alcohol. Higher BAC significantly predicted lower SSS, suggesting that alcohol inebriation alleviates simulator sickness. The negative relation between the number of previous exposures to the simulator and SSS was not statistically significant, but is consistent with habituation to the sickness-inducing effects, as shown in other studies. Overall, the results suggest no influence of simulator sickness on SDLP or several other driving performance measures. However, simulator sickness seems to cause test subjects to drive more carefully, with lower average speed and fewer steering wheel reversals, hampering the interpretation of these outcomes as measures of driving impairment and safety. BAC and repeated simulator exposures may act as confounding variables by influencing the degree of simulator sickness in experimental studies.
► This validation study compared simulated and real driving after ethanol intake. ► 20 subjects underwent three 1h trips each in a simulator and on a test track. ► Blood alcohol concentration and car ...weaving (SDLP) were significantly correlated. ► SDLP values were higher and showed greater variance in the simulator. ► The simulator is a sensitive and valid tool to detect ethanol impaired driving.
The purpose of this study was to establish and validate a driving simulator method for assessing drug effects on driving. To achieve this, we used ethanol as a positive control, and examined whether ethanol affects driving performance in the simulator, and whether these effects are consistent with performance during real driving on a test track, also under the influence of ethanol. Twenty healthy male volunteers underwent a total of six driving trials of 1h duration; three in an instrumented vehicle on a closed-circuit test track that closely resembled rural Norwegian road conditions, and three in the simulator with a driving scenario modelled after the test track. Test subjects were either sober or titrated to blood alcohol concentration (BAC) levels of 0.5g/L and 0.9g/L. The study was conducted in a randomised, cross-over, single-blind fashion, using placebo drinks and placebo pills as confounders. The primary outcome measure was standard deviation of lateral position (SDLP; “weaving”). Eighteen test subjects completed all six driving trials, and complete data were acquired from 18 subjects in the simulator and 10 subjects on the test track, respectively. There was a positive dose–response relationship between higher ethanol concentrations and increases in SDLP in both the simulator and on the test track (p<0.001 for both). In the simulator, this dose–response was evident already after 15min of driving. SDLP values were higher and showed a larger inter-individual variability in the simulator than on the test track. Most subjects displayed a similar relationship between BAC and SDLP in the simulator and on the test track; however, a few subjects showed striking dissimilarities, with very high SDLP values in the simulator. This may reflect the lack of perceived danger in the simulator, causing reckless driving in a few test subjects. Overall, the results suggest that SDLP in the driving simulator is a sensitive measure of ethanol impaired driving. The comparison with real driving implies relative external validity of the simulator.
Although alcohol consumption is related to increased cancer risk, its molecular mechanism remains unclear. Here, we demonstrate that an intake of 10% alcohol for 4 weeks in rats is genotoxic due to ...induction of micronuclei. Acetaldehyde (AA), the first product of ethanol metabolism, is believed to be responsible for DNA damage induced by alcohol. Here, we observe that AA effectively blocks DNA replication elongation in mammalian cells, resulting in DNA double-strand breaks associated with replication. AA-induced DNA damage sites colocalize with the homologous recombination (HR) repair protein RAD51. HR measured in the hypoxhantineguaninefosforibosyltransferase (HPRT) gene is effectively induced by AA and recombination defective mammalian cells are hypersensitive to AA, clearly demonstrating that HR is essential in the repair of AA-induced DNA damage. Altogether, our data indicate that alcohol genotoxicity related to AA produces replication lesions on DNA triggering HR repair.
Both the ERCC1-XPF complex and the proteins involved in homoIogous recombination (HR) have critical roles in inter-strand cross-link (ICL) repair. Here, we report that mitomycin C-induced lesions ...inhibit replication fork elongation. Furthermore, mitomycin C-induced DNA double-strand breaks (DSBs) are the result of the collapse of ICL-stalled replication forks. These are not formed through replication run off, as we show that mitomycin C or cisplatin-induced DNA lesions are not incised by global genome nucleotide excision repair (GGR). We also suggest that ICL-lesion repair is initiated either by replication or transcription, as the GGR does not incise ICL-lesions. Furthermore, we report that RAD51 foci are induced by cisplatin or mitomycin C independently of ERCC1, but that mitomycin C-induced HR measured in a reporter construct is impaired in ERCC1-defective cells. These data suggest that ERCC1-XPF plays a role in completion of HR in ICL repair. We also find no additional sensitivity to cisplatin by siRNA co-depletion of XRCC3 and ERCC1, showing that the two proteins act on the same pathway to promote survival.
► We studied greywater treatment capacity of compact filters using various substrates. ► Pilot-scale systems demonstrated good performance in COD, BOD, TSS and TP removal. ► Hydrated oil shale ash ...system showed better TP removal than Filtralite® systems. ► Basis is served to develop a low-tech compact filter system for greywater treatment.
Four parallel pilot-scale experimental filter systems were established in 2009 in order to study the treatment capacity of hydrated oil shale ash (an industrial by-product) and Filtralite® in compact highly loaded filter systems in order to reduce BOD and COD values and nutrient concentration in household greywater. The systems were tested at two different hydraulic loading rates over a nearly two-year period. All the Filtralite® systems performed significantly better than the oil shale ash system, showing a median COD reduction of 83–88%, whereas the system with 4–10mm crushed Filtralite® performed significantly better than others filled with Filtralite®. The oil shale ash system clearly outperformed the Filtralite® systems, with a median reduction of TP in the oil shale ash filter system of 89%, achieving a median effluent concentration of 0.55mgPL−1 compared to the respective 40–44% and 2.9–3.3mgPL−1 for Filtralite® systems. The median outflow pH values of the Filtralite® systems and oil shale ash system were ∼8.5 and ∼9, respectively. It was also noticeable that most of the organic matter, TSS and even TN and TP was removed in vertical flow (VF) filters. When operating the filter systems under ∼2.5 times higher loading rates, there were no significant differences between the removal efficiencies regarding the organic matter, TSS and TN removal, although the fluctuations of pollutant content in inflow were more distinctly reflected in the outflow values and concentrations. The study serves as a good basis for the development of a low-tech compact filter system for greywater treatment.
Quantitative Microbial Risk Assessment (QMRA) models with 10,000 Monte Carlo simulations were applied to ascertain the risks of rotavirus and Ascaris infections for farmers using different irrigation ...water qualities and consumers of lettuce irrigated with the different water qualities after allowing post-harvest handling. A tolerable risk (TR) of infection of 7.7 x 10(-4) and 1 x 10(-2) per person per year were used for rotavirus and Ascaris respectively. The risk of Ascaris infection was within a magnitude of 10(-2) for farmers accidentally ingesting drain or stream irrigation water; approximately 10(0) for farmers accidentally ingesting farm soil and 10(0) for farmers ingesting any of the irrigation waters and contaminated soil. There was a very low risk (10(-5)) of Ascaris infection for farmers using pipe-water. For consumers, the annual risks of Ascaris and rotavirus infections were 10(0) and 10(-3) for drain and stream irrigated lettuce respectively with slight increases for rotavirus infections along the post-harvest handling chain. Pipe irrigated lettuce recorded a rotavirus infection of 10(-4) with no changes due to post harvest handling. The assessment identified on-farm soil contamination as the most significant health hazard.
In the search for design criteria for constructed wetlands (CWs) in Nepal a semi-scale experimental setup including horizontal flow (HF) and vertical flow (VF) CWs was developed. This paper compares ...the performance of HF and VF wetlands, and planted with unplanted beds. The experimental setup consists of two units of HF and VF beds of size 6 m × 2 m × 0.6 m and 6 m × 2 m × 0.8 m (length × width × depth) respectively. For both HF and VF systems, one unit was planted with Phragmites karka (local reed) and one was not planted. The systems were fed with wastewater drawn from the grit chamber of a municipal wastewater treatment plant. The media consisted of river gravel. In the first phase of the experiment the hydraulic loading rate (HLR) was varied in steps; 0.2, 0.08, 0.04 m(3)/m(2)/d and the percent removal increase with decrease in HLR for all beds and parameters except for total phosphorus. In the second phase the loading rate of 0.04 m(3)/m(2)/d was run for 7 months. In both parts of the experiment the planted beds performed better than the unplanted beds and the VF better than the HF beds. To meet Nepalese discharge standards HF beds are sufficient, but to meet stricter requirements a combination of HF and VF beds are recommended.
This study discusses the influence of six bulking materials (peat, bark, oat husks, sawdust, food waste, and wheat bran) on the composting of blackwater solids (feces, urine and toilet paper) from ...low flush vacuum toilets (0.8 L/flush). The focus was on faecal indicator reduction, nutrient recycling, and carbon dioxide and methane emissions. In a composting experiment lasting 60 days, bulking materials were combined and mixed with blackwater solids, composted without stirring and with controlled aeration in a bench scale experiment. The bulking materials combination of oat husks, wheat bran and bark and of oat husks and wheat bran composted with blackwater solids showed the best results in terms of faecal indicator reduction (2.8 log10 reduction of Escherichia coli and 3.2 log10 reduction of faecal streptococci, respectively). Oat husks, bark and wheat bran combination had the smallest nutrient losses of 7.5% total nitrogen, 3.8% total phosphorus and 28% total potassium, while the highest accumulation in total phosphorus was 76.4% occurred in the mixture with oat husks and wheat bran. Peat and food waste improved the sorption of ammonia. The highest methane emissions (average 15.4%) were detected after 28 days of composting in the mixture with bran and food waste. Methane and carbon dioxide levels decreased in all the mixtures towards the end of composting indicating high organic matter degradation. Our findings show that a variety of natural and inexpensive materials can be used and adapted when composing blackwater in remote and sensitive areas.
Display omitted
•Blackwater from vacuum toilets was dewatered in a sequential filter system.•Blackwater solids were mixed with six bulk materials and composted without stirring.•Pathogens and greenhouse gases were reduced, nutrients were recycled.•Oat husks, wheat bran and bark mixture reduced E. coli in mesophilic conditions.•Optimizing blackwater solids compost mixtures contribute to improved sanitation.
Wastewater from a source-separated sanitation system connected to 24 residential flats was analysed for the content of organic matter and nutrients and other key parameters for microbiological ...processes used in the treatment and reuse of wastewater. Black water (BW) was the major contributor to the total load of organic matter and nutrients in the wastewater, accounting for 69% of chemical oxygen demand (COD), 83% of total nitrogen (N) and 87% of phosphorus (P). With a low COD/N ratio and high content of free ammonia, treating BW alone is a challenge in traditional biological nitrogen removal approaches. However, its high nitrogen concentration (1.4-1.7 g L
-1
) open up for nutrient reuse as well as for novel, more energy efficient N-removal technologies. Grey water (GW) contained low amounts of nutrients relative to organic matter, and this may limit biological treatment processes under certain conditions. GW contains a higher proportion of soluble, readily degradable organic substances compared with BW, which facilitates simple, decentralized treatment approaches. The concentration of organic matter and nutrients varied considerably between our study and other studies, which could be related to different toilet flushing volumes and water use habits. The daily load per capita, on the other hand, was found to be in line with most of the reported studies.
Although visual signage is the most common means of evacuation support in road tunnel emergencies, these can be of little help when there is dense smoke product of a fire. In such cases, auditory ...messages can lead evacuees out of a tunnel even in conditions with limited vision. This paper presents the results of two full-scale experimental studies designed to evaluate whether sound signals can help people to evacuate out of a smoke-filled tunnel due to a fire. Experiment 1 tested two sound signals (i.e. clicking sound and whistling sound) and their effect in aiding evacuation from a tunnel with poor vision. Experiment 2 was based on the results from Experiment 1 and tested two sound signals (i.e. clicking sound and bell sound). Experiment 2 confirmed that the evacuation success rate increased as people received information that they should follow the sound. In addition, subjective assessments by the participants revealed a higher preference for the tone-based sounds (i.e. bell sound and whistling sound) over the clicking sound. The results of this study can have implications in the assessment of new measures to support a more efficient evacuation from tunnels during emergencies.
Display omitted
•Sound signals can be used to lead persons in a wanted direction during tunnel evacuations.•Use of distributed loudspeakers can create an illusion of a sound moving through the tunnel.•Giving information about the sound increase the number of people choosing the wanted direction.
PDF
