The effectiveness of soft transport policy measures: A critical assessment and meta-analysis of empirical evidence

In the last few years there has been a growing interest in transport policy concerning behaviour oriented ‘soft’ measures to reduce private car use. Besides an assessment of the methodological quality of available evaluation results, the present paper focuses on a quantitative, meta-analytical synthesis of this empirical evidence. For these purposes a data set of 141 studies evaluating three types of soft transport policy measures was compiled mainly from already published narrative research reviews. The ability to draw strong causal inferences from the available research evidence is limited by the fact that all the retrieved evaluation studies use weak quasi-experimental designs. At least for one policy measure type our analyses also indicate the presence of a reporting bias. Across all three soft policy measures we found a statistically significant random-effects pooled effect size of 0.15. Translated into the original metric such an effect size indicates an increase in the no-car use proportion from 39% to 46%.     

Accounting for the effects of buoyancy on the turbulent scalar fluxes

Environmental Fluid Mechanics - The paper reports on the development of an explicit, algebraic model for the turbulent scalar fluxes which properly reflects the dependence of these fluxes on the...     

Nutzen und Grenzen von Modellökosystemen zur Erfassung der Wirkung von Schadstoffen auf benthische Lebensgemeinschaften

The aim of this short article is to deliver insight into the prospects and constraints of model ecosystems in the assessment of effects of contaminants on benthic communities, especially the meiofauna. Numerous substances accumulate in sediments and thus a complex contamination exists which is able to impair benthic organisms. Besides direct effects, indirect effects are of importance and should be considered. Changes in competition and predator-prey-relationships lead to a variety of effects in the benthic food web that cannot be explained by direct toxicity of contaminants. In this article two microcosm studies, one with the heavy metal cadmium and one with the veterinary pharmaceutical Ivermectin, are presented which both showed direct as well as indirect effects. A significant change in abundance and composition of the meiofauna community has been observed. The prediction of field-effects of a certain substance as well as the interpretation of field data are the aims of model ecosystems. Both studies proofed that the investigation of meiofauna in microcosms is a promising tool to achieve these aims. Furthermore, microcosms with meiofauna might be able to assist the effect-directed analysis (EDA) in a risk assessment by identifying the effect-causing contaminants of complex environmental samples.     

Association of <Emphasis Type="Italic">Waminoa</Emphasis> sp. (Acoela) with corals in the Wakatobi Marine Park,South-East Sulawesi,Indonesia

This is the first quantitative study on the prevalence of epizoic Waminoa sp. acoel worms and their association with corals in the Wakatobi Marine National Park (WMNP), South-East Sulawesi, Indonesia. Three replicate transects were laid on the reef crest, flat and slope at six sites in 2006 and eight sites in 2007. Four of the sites were common in both years. In total 69 transects were surveyed in 2006, and 87 transects in 2007. A total of 4.8% of all observed hard corals were associated with acoel worms in 2006 and 2.6% of hard and soft corals in 2007. Acoels were present on 16 and 21 of the coral taxa studied in 2006 and 2007 respectively. The worms were strongly associated with the azooxanthellate coral Tubastrea spp. and were rare or absent on the most abundant coral genera Montipora and Porites. The mean number of corals having acoels was highest on reef slopes, whereas acoels were virtually absent on reef flats. Corals that had a high and a medium cover of worms were more common in 2007 than in 2006. No significant trend in the adaptation of the zooxanthellae of Waminoa sp. to different depths at different sites was revealed. The impact of the worm on the coral is unknown, but high numbers may have a shading effect and a negative impact on the coral’s photophysiology. This acoel merits more study of its life cycle, its photophysiology, and its impact on its host corals. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Modeling of the reburning process using sewage sludge-derived syngas

Gasification of sewage sludge can provide clean and effective reburning fuel for combustion applications. The motivation of this work was to define the reburning potential of the sewage sludge gasification gas (syngas). A numerical simulation of the co-combustion process of syngas in a hard coal-fired boiler was done. All calculations were performed using the Chemkin programme and a plug-flow reactor model was used. The calculations were modelled using the GRI-Mech 2.11 mechanism. The highest conversions for nitric oxide (NO) were obtained at temperatures of approximately 1000-1200 K. The combustion of hard coal with sewage sludge-derived syngas reduces NO emissions. The highest reduction efficiency (>90%) was achieved when the molar flow ratio of the syngas was 15%. Calculations show that the analysed syngas can provide better results than advanced reburning (connected with ammonia injection), which is more complicated process.     

Cuttlebone calcification increases during exposure to elevated seawater pCO2 in the cephalopod Sepia officinalis

Changes in seawater carbonate chemistry that accompany ongoing ocean acidification have been found to affect calcification processes in many marine invertebrates. In contrast to the response of most invertebrates, calcification rates increase in the cephalopod Sepia officinalis during long-term exposure to elevated seawater pCO₂. The present trial investigated structural changes in the cuttlebones of S. officinalis calcified during 6 weeks of exposure to 615 Pa CO₂. Cuttlebone mass increased sevenfold over the course of the growth trail, reaching a mean value of 0.71 ± 0.15 g. Depending on cuttlefish size (mantle lengths 44–56 mm), cuttlebones of CO₂-incubated individuals accreted 22–55% more CaCO₃ compared to controls at 64 Pa CO₂. However, the height of the CO₂-exposed cuttlebones was reduced. A decrease in spacing of the cuttlebone lamellae, from 384 ± 26 to 195 ± 38 μm, accounted for the height reduction The greater CaCO₃ content of the CO₂-incubated cuttlebones can be attributed to an increase in thickness of the lamellar and pillar walls. Particularly, pillar thickness increased from 2.6 ± 0.6 to 4.9 ± 2.2 μm. Interestingly, the incorporation of non-acid-soluble organic matrix (chitin) in the cuttlebones of CO₂-exposed individuals was reduced by 30% on average. The apparent robustness of calcification processes in S. officinalis, and other powerful ion regulators such as decapod cructaceans, during exposure to elevated pCO₂ is predicated to be closely connected to the increased extracellular [HCO₃ ⁻] maintained by these organisms to compensate extracellular pH. The potential negative impact of increased calcification in the cuttlebone of S. officinalis is discussed with regard to its function as a lightweight and highly porous buoyancy regulation device. Further studies working with lower seawater pCO₂ values are necessary to evaluate if the observed phenomenon is of ecological relevance.     

Food selection in larval fruit flies: dynamics and effects on larval development

Selecting food items and attaining a nutritionally balanced diet is an important challenge for all animals including humans. We aimed to establish fruit fly larvae (Drosophila melanogaster) as a simple yet powerful model system for examining the mechanisms of specific hunger and diet selection. In two lab experiments with artificial diets, we found that larvae deprived of either sucrose or protein later selectively fed on a diet providing the missing nutrient. When allowed to freely move between two adjacent food patches, larvae surprisingly preferred to settle on one patch containing yeast and ignored the patch providing sucrose. Moreover, when allowed to move freely between three patches, which provided either yeast only, sucrose only or a balanced mixture of yeast and sucrose, the majority of larvae settled on the yeast-plus-sucrose patch and about one third chose to feed on the yeast only food. While protein (yeast) is essential for development, we also quantified larval success on diets with or without sucrose and show that larvae develop faster on diets containing sucrose. Our data suggest that fruit fly larvae can quickly assess major nutrients in food and seek a diet providing a missing nutrient. The larvae, however, probably prefer to quickly dig into a single food substrate for enhanced protection over achieving an optimal diet.