A survey of operational definitions of hazardous road locations in some European countries

This paper presents the results of a survey of operational definitions of hazardous road locations in some European countries. The term operational definition refers to the criteria and methods used to identify hazardous road locations. Eight countries were included in the survey. The operational definitions of hazardous road locations used in these countries were compared in terms of six characteristics:

• 1. 

  Whether hazardous road locations are identified by reference to a population of similar sites, i.e. by means of sampling from a predefined list of sites or identified without referring to any population of sites.

• 2. 

  Whether a sliding window method is used to identify hazardous road locations.

• 3. 

  Whether hazardous road locations are identified in terms of deviance from a normal level of safety or without reference to a normal level of safety.

• 4. 

  Whether hazardous road locations are identified in terms of the recorded or expected number of accidents.

• 5. 

  Whether accident severity is considered in identifying hazardous road locations or not.

• 6. 

  The length of the period used to identify hazardous road locations.

Most operational definitions of hazardous road locations were found: (1) not to refer to any population of similar sites, (2) to rely on a sliding window approach, and (3) identify hazardous road locations in terms of the recorded number of accidents. In four of the countries, hazardous road locations are identified as sites that have significantly more accidents than the normal number. Accident severity was considered in four of the countries. The period used to identify hazardous road locations varied between 1 and 5 years.Compared to state-of-the-art techniques for identifying hazardous road locations, most of the approaches used in the countries surveyed were primitive and are likely to involve substantial inaccuracies. Steps that can be taken to bring practice closer to the state-of-the-art are outlined.     

The predictive validity of empirical Bayes estimates of road safety

This paper examines the predictive validity of empirical Bayes (EB) estimates of road safety. The predictive performance of EB-estimates was tested by applying five versions of EB-estimates of road safety:

• (1) 

  A simple estimate derived from the empirical distribution of accidents in a population of sites, by which the number of accidents predicted for period 2 for sites that recorded k accidents in period 1 equals the number of accidents for sites that recorded k + 1 accidents in period 1.

• (2) 

  Estimates derived from the parameters of a negative binomial distribution fitted to an empirical distribution of accidents in a population of sites by means of the method of moments.

• (3) 

  Estimates derived from the parameters of a negative binomial distribution fitted to an empirical distribution of accidents in a population of sites by means of the maximum likelihood technique.

• (4) 

  Estimates derived by combining the predictions of an accident prediction model and the recorded number of accidents for a site.

• (5) 

  Estimates derived by combining the predictions of a different version of an accident prediction model and the recorded number of accidents for a site.

All versions of EB-estimates are compared to the traditional, naïve assumption of treating the recorded number of accidents as an unbiased estimate of the expected number of accidents.To test the predictive performance of EB-estimates, data for two periods was used. EB-estimates based on data for the first period were treated as predictions of the number of accidents in the second period for road sections that had 0, 1, 2, etc., accidents in the first period, the idea being that the more accurate the prediction, the more accurate the result of a before-and-after study.All versions of EB-estimates were found to give considerably more correct predictions of the number of accidents in the second period than relying on the count of accidents in the first period as a prediction of the count in the second period. Smaller prediction errors were associated with predictions based on accident prediction models than predictions not based on such models.     

Comprehensive comparison of collision induced dissociation and electron transfer dissociation

Electron transfer dissociation (ETD) is a recently introduced mass spectrometric technique which has proven to be an excellent tool for the elucidation of labile post-translational modifications such as phosphorylation and O-GlcNAcylation of serine and threonine residues. However, unlike collision induced dissociation (CID), which has been studied for decades, the intricacies of ETD-based fragmentation have not yet been firmly established or systematically addressed. In this analysis, we have systematically compared the CID and ETD fragmentation patterns for the large majority of the peptides that do not contain such labile modifications. Using a standard 48 protein mix, we were able to measure false-positive rates for the experiments and also assess a large number of peptides for a detailed comparison of CID and ETD fragmentation pattern. Analysis of approximately 19,000 peptides derived from both standard proteins and complex protein samples revealed that (i) CID identified 50% more peptides than ETD; (ii) ETD resulted in approximately 20% increase in amino acid sequence coverage over CID; and (iii) combining CID and ETD fragmentation increased the sequence coverage for an average tryptic peptide to 92%. Interestingly, our analysis revealed that nearly 60% of all ETD-identified peptides carried two positive charges, which is in sharp contrast to what has been generally accepted. We also present a novel strategy for automatic validation of peptide assignments based on identification of a peptide by consecutive CID and ETD fragmentation in an alternating mode.     

Assessing the efficiency of priorities for traffic law enforcement in Norway

This paper assesses the efficiency of priorities for traffic law enforcement in Norway. Priorities are regarded as efficient if: (1) enforcement ensures a sufficient level of deterrence to keep down the rate of violations; (2) selection of target violations for enforcement is based on the risk attributable to them; and (3) an optimal level of enforcement is selected, i.e. the marginal benefits of enforcement in terms of preventing accidents equal the marginal costs of enforcement. The efficiency of current traffic law enforcement in Norway is assessed in terms of these criteria. It is found that the risk of apprehension varies considerably between different traffic violations. These variations do not reflect the risk attributable to the violations, i.e. it is not the case that the risk of apprehension is higher for violations that make a large contribution to fatalities and injuries than for violations that make a smaller contribution. In principle, shifting priorities so as to increase the risk of apprehension for some violations and reduce it for other violations could make police enforcement slightly more efficient. The main finding, however, is that the current level of enforcement is too low. Cost-benefit analyses show that substantially increasing the amount of police enforcement is cost-effective.     

An evaluation of teeth of ringed seals (Phoca hispida) from Greenland as a matrix to monitor spatial and temporal trends of mercury and stable isotopes

Total mercury (Hg) concentrations were measured in teeth of ringed seals from Qeqertarsuaq, central West Greenland (1982 to 2006) and Ittoqqortoormiit, central East Greenland (1986 to 2006). Stable isotopic ratios of carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N) were determined as well to provide insights into diet variations between regions or through time. Mercury concentrations decreased the first years of life of the animals suggesting that Hg had been transferred from the mother to the foetus and newborn. The Hg concentrations in teeth were significantly lesser in ringed seals from central West Greenland compared to those from central East Greenland. Carbon and nitrogen stable isotopic values measured in the animals differed also significantly between the two regions. Increasing temporal trends of dental Hg concentrations between 1994 and 2006 were observed in ringed seals from both central West Greenland and central East Greenland. These increases were attributed to global changes in environmental Hg levels since no temporal trends in δ¹⁵N values were found to support the hypothesis of a diet shift over time. Furthermore, a decreasing temporal trend in δ¹³C values was observed in the teeth of seals from central East Greenland, and explained by a likely change over time towards more pelagic feeding habits; alternatively, the so-known Seuss effect was thought to be responsible for this decrease. Finally, it was concluded that the tooth of ringed seal was a good monitoring tissue to assess Hg trends.     

Effects of Noble Metal Promoters on In Situ Reduced Low Loading Ni Catalysts for Methane Activation

The commercial potential for a given catalytic process may be influenced by requirements on metal loading, in particular where noble metals are used. In an effort to substantially decrease the amount of catalyst material used for methane activation and catalytic partial oxidation (CPO), the effect of 0.005 wt% noble metal (Rh, Ru, Pd or Pt) on 0.5 wt% Ni/γ-Al₂O ₃ catalysts have been studied at temperatures below 1,173 K and 1 atm. The successful catalysts were activated directly by in situ reduction, without a calcination step, to promote formation of a highly dispersed (supported) metal phase from nitrate precursors. The obtained metal particles were not observable by XRD (size <  2–3 nm). This activation procedure had a decisive effect on catalyst activity, as compared to a catalyst which was calcined ex situ before in situ reduction. Adding a noble metal caused a significant drop in the ignition temperature during temperature programmed catalytic partial oxidation (TPCPO). The ignition temperature for partial oxidation coincides well with the temperature for methane dissociation, and is likely correlated to the reducibility of the noble metal oxide. Methane partial oxidation over 0.5 wt% Ni catalysts, both with and without promoter, yielded high selectivity to synthesis gas (>93%) and stable performance for continued operation, but synthesis gas production at temperatures below 1,073 K required a promoter when the catalyst was ignited by TPCPO. Ignition of the CPO reactions by introducing the feed at a high furnace temperature (1,073 K) also enabled formation of synthesis gas, but the reaction was then less stable than obtained with the TPCPO procedure. A dual bed concept attempted to beneficially use the activation and combustion properties of the noble metal followed by the reforming properties of Ni. However, it was concluded that co-impregnated catalysts yielded as high, or even higher conversion of methane and selectivity to synthesis gas.     

Analytic choices in road safety evaluation: Exploring second-best approaches

Conducting rigorous before-and-after studies is essential for improving knowledge regarding the effects of road safety measures. However, state-of-the-art approaches like the empirical Bayes or fully Bayesian techniques cannot always be applied, as the data required by these approaches may be missing or unreliable. The choice facing researchers in such a situation is to either apply “second-best” approaches or abstain from doing an evaluation study. An objection to applying second-best approaches is that these approaches do not control as well for confounding factors as state-of-the-art approaches. This paper explores the implications of choice of study design by examining how the findings of several evaluation studies made in Norway depend on choices made with respect to:

1.

Using the empirical Bayes approach versus using simpler approaches;     

The effect of technology information on consumer expectations and liking of beef

European consumers increasingly attach value to process characteristics of food. Although beef technologies are hardly communicated to consumers, providing consumer-oriented information about technology application might increase perceived transparency and consumer acceptance. This study investigates how information about beef technologies influences consumer expectations and liking of beef. Beef consumers in Belgium (n = 108) and Norway (n = 110) participated in an information experiment combined with sensory testing in which each consumer tasted three beef muscles treated with different technologies: unprocessed tenderloin M. Psoas major, muscle profiled M. Infraspinatus, and marinated (by injection) M. Semitendinosus. The findings indicate that detailed information about beef technologies can enhance consumers' expectations and liking of beef. However, this effect differs between countries and beef technologies. Information becomes either less relevant when the product is actually tasted, as indicated by the findings in Norway, or more relevant when information is confirmed by own experience during tasting, as indicated by the findings in Belgium.