The need for work: Jahoda's latent functions of employment in a representative sample of the German population

Marie Jahoda's latent deprivation model was tested with a representative sample of the German population (N = 998). As expected, employees reported high levels of time structure, social contact, collective purpose, and activity not only in comparison to unemployed persons but also in comparison to persons who are out of the labor force (i.e., students, homemakers, retirees). Even unskilled manual workers reported more access to these “latent functions” than persons without employment. For the fifth of Jahoda's dimensions, identity/status, no significant differences between employed persons and persons who are out of the labor force could be identified. However, unemployed persons reported less status than all other groups did. Thus, Jahoda's model was clearly endorsed for four of the five latent functions of employment and partly endorsed for the fifth function. All variables in the model correlated significantly with distress, as expected. Demographic correlates of the manifest and latent functions were also analyzed: Access to the latent functions was best among young men from higher social classes who lived in an intimate relationship in a comparatively large household with children. Copyright © 2009 John Wiley & Sons, Ltd.     

An outlook on Dutch road safety in 2020; future developments of exposure,crashes and policy

This paper discusses the method used for an outlook on road safety in the Netherlands until 2020. The objectives of the outlook are to judge the feasibility of the Dutch road safety policy targets and to estimate the effects in 2020 of new measures. The outlook consists of baseline forecasts assuming the unchanged continuation of the effect of current road safety policy as a starting point, and the effect of new measures on top of that. We used four different mobility scenarios, derived from a comprehensive study about the macro-economic development of Dutch society until 2040. In the mobility scenario with the largest growth it appeared doubtful whether the policy targets of that time for the maximum number of fatalities in 2020 (580) can be achieved. An extensive inventory of new measures after 2010 produced five already intended new measures, the effects of which were estimated. The results show that the target of maximum 580 fatalities in 2020 can probably be met. The recently adjusted policy target of 500 fatalities in 2020 is also feasible if additional new measures are taken.     

Age group differences in collision risk

Introduction

The purpose of the current study was to examine differences in factors associated with self-reported collision involvement of three age groups of drivers based on a large representative sample of Ontario adults. Method: This study was based on data from the CAMH Monitor, an ongoing cross-sectional telephone survey of Ontario adults 18 years and older from 2002 to 2005. Three age groups were examined: 18-34 (n = 1,294), 35-54 (n = 2,428), and 55+ (n = 1,576). For each age group sample, a logistic regression analysis was conducted of self-reported collision involvement in the last 12 months by risk factor measures of driving exposure (kilometers driven in a typical week, driving is stressful, and driving on busy roads), consuming five or more drinks of alcohol on one occasion (past 12 months), cannabis use (lifetime, and past 12 months), and driving after drinking among drinkers (past 12 months), controlling for demographics (gender, region, income, and marital status). Results: The study identified differences in factors associated with self-reported collision involvement of the three age groups of adult drivers. The logistic regression model for the youngest group revealed that drivers who reported that driving was stressful at least some of the time, drank five or more drinks on an occasion, and drove after drinking had an increased risk of collision involvement. For the middle age group, those who reported using cannabis in the last 12 months had significantly increased odds of reporting collision involvement. None of the risk factor measures showed significant associations with collision risk for older drivers (aged 55+). Impact: The results suggest potential areas for intervention and new directions for future research.     

Oxidative properties of ambient PM2.5 and elemental composition: Heterogeneous associations in 19 European cities

We assessed the extent to which constituents of PM_2.5 (transition metals, sodium, chloride) contribute to the ability to generate hydroxyl radicals (OH) in vitro in PM_2.5 sampled at 20 locations in 19 European centres participating in the European Community Respiratory Health Survey. PM_2.5 samples (n = 716) were collected on filters over one year and the oxidative activity of particle suspensions obtained from these filters was then assessed by measuring their ability to generate OH in the presence of hydrogen peroxide. Associations between OH formation and the studied PM constituents were heterogeneous. The total explained variance ranged from 85% in Norwich to only 6% in Albacete. Among the 20 centres, 15 showed positive correlations between one or more of the measured transition metals (copper, iron, manganese, lead, vanadium and titanium) and OH formation. In 9 of 20 centres OH formation was negatively associated with chloride, and in 3 centres with sodium. Across 19 European cities, elements which explained the largest variations in OH formation were chloride, iron and sodium.     

Potential concerns related to using octadecyltrichlorosilane (OTS) in rendering soils and porous ceramics hydrophobic

The treatment of hydrophilic porous ceramics to render them hydrophobic and wetting to non-aqueous phase liquids (NAPLs) is frequently needed in multiphase flow experiments to control the flow or to measure the pressure of the NAPL. In addition, research dealing with soil wettability implies a need for hydrophobic or NAPL-wet soils. The traditional procedure, which has been widely used in literature, to render hydrophilic porous ceramics and soils hydrophobic is achieved by placing the hydrophilic solid in a 5% (by volume) octadecyltrichlorosilane (OTS) solution in ethanol followed by rinsing in ethanol. This research assesses the use of this procedure as it was found that this treatment procedure resulted in excess OTS on the surface of treated hydrophobic solids which can dissolve in an organic phase and in turn alter the wettability condition of adjacent hydrophilic soils. A modified procedure, which results in hydrophobic solids free of excess OTS, is presented.     

Analysis of air pollution data at a mixed source location using boosted regression trees

This paper explores the use of boosted regression trees to draw inferences concerning the source characteristics at a location of high source complexity. Models are developed for hourly concentrations of nitrogen oxides (NO_X) close to a large international airport. Model development is discussed and methods to quantify model uncertainties developed. It is shown that good explanatory models can be developed and further, allowing for interactions between model variables significantly improves the model fits compared with non-interacting models. Methods are used to determine which variables exert most influence over predicted concentrations and to explore the NO_X dependency for each. Model predictions are used to estimate aircraft take-off contributions to total concentrations of NO_X and determine how these predictions are affected by annual variations in meteorological conditions and runway use patterns. Furthermore, the results relating to the aircraft contributions to total NO_X concentration are compared with those from a more detailed independent field campaign. Finally, we find empirical evidence that plumes from larger aircraft disperse more rapidly from the point of release compared with smaller aircraft. The reasons for this behaviour and the implications are discussed.     

Ammonia emissions from a representative in-use fleet of light and medium-duty vehicles in the California South Coast Air Basin

We used Fourier Transform Infrared Spectroscopy (FTIR) to measure tailpipe ammonia emissions from a representative fleet of 41 light and medium-duty vehicles recruited in the California South Coast Air Basin. A total of 121 chassis dynamometer emissions tests were conducted on these vehicles and the test results were examined to determine the effects of several key variables on ammonia emissions. Variables included vehicle type, driving cycle, emissions technology, ammonia precursor emissions (i.e. CO and NOx) and odometer readings/model year as a proxy for catalyst age. The mean ammonia emissions factor was 46 mg km^?1 (σ = 48 mg km^?1) for the vehicle fleet. Average emission factors for specific vehicle groups are also reported in this study. Results of this study suggest vehicles with the highest ammonia emission rates possess the following characteristics: medium-duty vehicles, older emissions technologies, mid-range odometer readings, and higher CO emissions. In addition, vehicles subjected to aggressive driving conditions are likely to be higher ammonia emitters. Since the vehicles we studied were representative of recent model year vehicles and technologies in urban airsheds, the results of our study will be useful for developing ammonia emissions inventories in Los Angeles and other urban areas where California-certified vehicles are driven. However, efforts should also be made to continue emissions testing on in-use vehicles to ensure greater confidence in the ammonia emission factors reported here.     

The relationship between the implementation of a Safety Management System and the attitudes of employees towards unsafe acts in aviation

Airports represent highly complex organisations, incorporating such interdependent operations as airlines, ground transport, flight services, ground services, refueling, maintenance, customer services, catering, administration and security. Airports, and especially International Airports, must ensure that their operations are conducted in a safe and efficient manner, as the consequence of any error or failure during operations has the potential for catastrophic outcomes. The international governing body for air transportation, ICAO, requires that airports must implement a Safety Management System as a means of ensuring safe operations and eliminating or reducing the likelihood of low frequency/high consequence incidents. This research project sought to determine the extent to which the implementation of a Safety Management System (SMS) influenced the attitudes of airport employees toward unsafe acts. The hypothesis tested was that the implementation of an SMS into an airport will result in an improvement in attitudes toward safety. A Safety Culture Survey was utilized to measure these attitudes. Two International Airports were chosen to measure the extent to which the introduction of an SMS at one airport would influence the safety attitude and culture of those employees. Sharjah International Airport, UAE, was used as the experimental group, as it did not have a formal SMS in operation, with another English-speaking International Airport (the Second Airport) being used as a control group, as it already had an SMS in operation. A Safety Culture Survey was used as the pre and post-test measure over a 12-month period to determine the extent of influence of the introduction of the SMS at Sharjah Airport. The results of Phase 1 of the survey (June 2008) were compared against the results of Phase 2 of the survey (June 2009). The average score reported by participants at Sharjah Airport increased significantly from pre-test measure to post-test measure in relation to communication, safety rules, supportive environment, personal risk appreciation, work environment, and involvement. At the same time, the average score for personal priorities decreased significantly from Phases 1 to 2. Results indicate that participants at Sharjah Airport recorded a significant positive shift in attitude to the safety factors covered in the Safety Culture Survey, whilst at the same time responses from the Second Airport showed no such shift in attitude. The Second Airport showed neither decline nor improvement in responses. Whilst some methodological issues were identified, the results were of sufficient strength as to conclude that the outcomes reported support the hypothesis that the introduction of an SMS at Sharjah Airport has effected positive changes not observed at the Second Airport. Recommendations for ongoing research were made to further explore the strength of relationship between SMS and safety attitudes, as well as the relationship between safe attitude and safe behaviour.