Crash risk of ESC-fitted passenger cars

Objective: We examined both fatal and injury at-fault crashes of a population of passenger cars fitted with electronic stability control (ESC). Crash rates were calculated in relation to both registration years and mileage. Crash rates were also calculated for a non-ESC car population and crash rate ratios were calculated to compare the crash risk between ESC-fitted and non-ESC-fitted passenger cars.

Methods: Passenger car models with and without ESC were identified (ESC-equipped cars: 3,352,813 registration years; non-ESC-equipped: 5,839,946 registration years) and their vehicle information for the period 2009–2013, including mileage (ESC-equipped vehicles: 89.3 billion kilometers; non-ESC-equipped: 72.4 billion kilometers), was drawn from the national Vehicular and Driver Data Register.

The registry of Finnish road accident investigation teams was accessed and all fatal at-fault crashes among the cars in the study populations (ESC 97; non-ESC 377) for the period 2009–2013 were analyzed. The motor insurance database includes at-fault crashes leading to injuries and was utilized for analyses (ESC: N?=?8,827, non-ESC: N?=?21,437).

Crash rates and crash rate ratios were calculated to evaluate crash risk of both ESC-equipped and non-ESC-equipped passenger cars. Poisson regression was used to model crash involvement rate ratios both per registration year and per mileage for vehicles with ESC and without ESC, controlling for age and gender of the vehicle owner and vehicle mass.

Results: Passenger cars fitted with ESC showed lower crash rates than non-ESC-equipped cars in all crash types studied. In general, the difference in crash rates between ESC-equipped and non-ESC-equipped vehicles was greater when the crashes were compared to the mileage rather than registration years. The mileage-proportional crash rate of ESC-equipped cars was 64% (95% confidence interval, 61%; 67%) lower in run-off-road crashes resulting in injury and as much as 82% (65%; 91%) lower in fatal run-off-road crashes when suicides and disease attacks were not taken into account.

Conclusions: Our results show that modern passenger cars provide a significant crash risk reduction, which depends on both ESC and passive safety features introduced. Results also show that exposure evaluation in terms of registration years (or vehicle population) instead of true mileage can provide an overly pessimistic view of the crash risk.     

Insect herbivory may cause changes in the visual properties of leaves and affect the camouflage of herbivores to avian predators

Behavioral Ecology and Sociobiology - An individual’s metabolic competence is important when escalating to costly behaviours in agonistic encounters. The use of broken shells in the wild...     

Phosphorus removal in a wetland constructed on former arable land

Phosphorus in surface runoff water may cause eutrophication of recipient water. This study clarifies the mechanisms of P removal in the wetland of Hovi, Finland, constructed on arable land in 1998. Before the construction, the surface soil (removed in the construction) and subsoil (the current wetland bottom) were analyzed for Al and Fe oxides (Al(ox) and Fe(ox)) reactive in P sorption, and for the distribution of P between various pools as well as for P exchange properties. Retention of P from runoff water within the wetland was studied from 1999 to 2001 in situ and factors affecting the P removal (O2 availability and P concentration in water) were investigated in a laboratory microcosm. The processes taking place in the wetland diminished by 68% the total P load and by 49% the dissolved reactive P load. Desorption-sorption tests indicated that without removal of the surface soil, there would have been a risk of the wetland being a source of P, since the equilibrium P concentration of the soil removed was high compared with the mean P concentration of the inflowing water. The subsoil contained less P and high amounts of reactive oxides, which could bind P. Evidently, the P sorption by Al(ox) played an important role in a first phase removal of P, since the wetland retained P efficiently even under anoxic conditions, where Fe tends to be reduced. Fine-textured, mineral soil on the bottom of the wetland (subsoil of the former arable land) seemed to be very efficient in retaining P from agricultural runoff.     

Pup production and breeding distribution of the Caspian seal (Phoca caspica) in relation to human impacts

Aerial surveys of Caspian seals on the winter ice field in Kazakhstan territorial waters were carried out in February 2005 and 2006 to assess the annual pup production for the species and natural predation on newborn pups. Estimated pup production was 21063 in 2005 and 16905 in 2006 (including an estimated figure for pups born in Russian territory in each year). The breeding population size of approximately 20 000 females is much less than published estimates from the late 1980s. Eagles were the principal natural predators of pups. Commercial icebreaker routes passed through areas of dense pup concentrations in 2006, although not in 2005. Our findings have important implications for the development of conservation strategies for the species. Natural mortality, loss to predators, and, more important, the current hunting quota substantially exceed the recruitment of the Caspian seal population. Anthropogenic sources of mortality should be managed to avoid further declines in the species.     

Experimental test of parasitism hypothesis for population cycles of a forest lepidopteran

Population cycles of herbivores are thought to be driven by trophic interaction mechanisms, either between food plant and herbivore or between the herbivorous prey and its natural enemies. Observational data have indicated that hymenopteran parasitoids cause delayed density-dependent mortality in cyclic autumnal moth (Epirrita autumnata) populations. We experimentally tested the parasitism hypothesis of moth population cycles by establishing a four-year parasitoid-exclusion experiment, with parasitoid-proof exclosures, parasitoid-permeable exclosures, and control plots. The exclusion of parasitoids led to high autumnal moth abundances, while the declining abundance in both the parasitoid-permeable exclosures and the control plots paralleled the naturally declining density in the study area and could be explained by high rates of parasitism. Our results provide firm experimental support for the hypothesis that hymenopteran parasitoids have a causal relationship with the delayed density-dependent component required in the generation of autumnal moth population cycles.