Precision,accuracy, and application of diver-towed underwater GPS receivers

Diver-towed global positioning systems (GPS) handhelds have been used for a few years in underwater monitoring studies. We modeled the accuracy of this method using the software KABKURR originally developed by the University of Rostock for fishing and marine engineering. Additionally, three field experiments were conducted to estimate the precision of the method and apply it in the field: (1) an experiment of underwater transects from 5 to 35 m in the Southern Chile fjord region, (2) a transect from 5 to 30 m under extreme climatic conditions in the Antarctic, and (3) an underwater tracking experiment at Lake Ranco, Southern Chile. The coiled cable length in relation to water depth is the main error source besides the signal quality of the GPS under calm weather conditions. The forces used in the model resulted in a displacement of 2.3 m in a depth of 5 m, 3.2 m at a 10-m depth, 4.6 m in a 20-m depth, 5.5 m at a 30-m depth, and 6.8 m in a 40-m depth, when only an additional 0.5 m cable extension was used compared to the water depth. The GPS buoy requires good buoyancy in order to keep its position at the water surface when the diver is trying to minimize any additional cable extension error. The diver has to apply a tensile force for shortening the cable length at the lower cable end. Repeated diving along transect lines from 5 to 35 m resulted only in small deviations independent of water depth indicating the precision of the method for monitoring studies. Routing of given reference points with a Garmin 76CSx handheld placed in an underwater housing resulted in mean deviances less than 6 m at a water depth of 10 m. Thus, we can confirm that diver-towed GPS handhelds give promising results when used for underwater research in shallow water and open a wide field of applicability, but no submeter accuracy is possible due to the different error sources.     

Natural radioactivity in winter wheat from organic and conventional agricultural systems

The distribution of natural radionuclides was studied in winter wheat plants collected from three sites in Belgium during 2004-2007. Activity concentrations of ⁴⁰K, ²²⁶Ra, ²²⁸Ra and ²²⁸Th in organically and conventionally grown wheat, and in the corresponding soil samples, were determined using ultra low-level gamma-ray spectrometry. The observed soil-to-wheat concentration ratios were calculated for the different parts of the wheat plant (root, stem and grain) in the two agricultural systems (organic and conventional). There were large variations in radionuclide activity concentrations between the sites and fields, but no significant difference between conventionally and organically grown wheat plants was observed.     

Long-term air monitoring of organochlorine pesticides using Semi Permeable Membrane Devices (SPMDs) in the Alps

Atmospheric sampling of organochlorine pesticides (OCPs) was conducted using Semi Permeable Membrane Devices (SPMDs) deployed in the Alps at different altitudinal transects for two consecutive exposure periods of half a year and a third simultaneous year-long period. Along all the altitude profiles, the sequestered amounts of OCPs increased in general with altitude. SPMDs were still working as kinetic samplers after half a year for the majority of the OCPs. However, compounds with the lowest octanol-air partition coefficient (K_oa), reached equilibrium within six months. This change in the SPMD uptake was determined for the temperature gradient along the altitude profile influencing K_oa, OCPs availability in the gaseous phase, and SPMD performance. In sum, it seems two effects are working in parallel along the altitude profiles: the change in SPMD performance and the different availability of OCPs along the altitudinal transects determined by their compound properties and concentrations in air.     

Evaluation by policy makers of a procedure to describe perceived landscape openness

In the last decade policy makers have increasingly recognized the need to include people's perceptions in methods for describing landscape quality. At the same time, a third wave of Geographic Information Systems (GIS) has become available that make it technically possible to model landscape quality in a realistic manner. However, as there is often a mismatch between science and policy, it remains unclear to what extent perception-based models developed by scientists can be useful to policy makers. The aim of the present study was to evaluate the usefulness to policy making of a GIS-based procedure for describing perceived landscape openness. To this end, a workshop was organized which was attended by eight Dutch policy makers who acted as representatives of their province (region). The Group Decision Room (GDR) technique was used to elicit the policy makers' evaluations of the procedure in an anonymous and reliable manner. The procedure was presented to the policy makers using cases from their own province, which they assessed using a mixture of qualitative and quantitative methods. The results show that policy makers rated the procedure as being highly relevant to policy making, scientifically credible, usable by policy makers and feasible to implement in the policy making process. They especially appreciated the flexibility and transparency of the procedure. The policy makers concluded that the procedure would be of most value for monitoring landscape changes and for analysing impacts on landscape openness in land use scenario studies. However, they requested guidelines for proper implementation of the various options in the procedure. In general, the current study shows that explicit and transparent evaluation of the usefulness of GIS-based tools can aid integration at the science-policy interface and help to ensure that both scientists and policy makers are informed of interrelated options and requirements.     

Policies to promote sustainable consumption: Innovative approaches in Europe

Policy-makers are increasingly recognising that the promotion of more sustainable consumption patterns is an indispensable prerequisite for achieving sustainable development in the long term. Policy documents and action plans have been published, and a wide array of policy instruments has been implemented with the aim of reducing the environmental and social burdens of consuming goods and services. But what are the latest trends and innovative approaches in sustainable consumption (SC) policies? What could be learnt for future policy-making? Based on an overview of European policy instruments and several case studies, the paper discusses instructive examples of SC policy instruments, in particular the Danish information campaign "One Tonne Less", the Dutch tax incentive scheme "Green Funds", the British "Red/Green calculator", and the pan-European internet platform "TopTen". Important features of novel policies — such as adaptability and collective action — are identified, and recommendations for future policies are presented. The recommendations refer to the foundation of SC policies, to the specific approach taken, to the applied instruments, and to the proper documentation of the implemented policies.     

Simultaneous monitoring of PCB profiles in the urban air of Dalian, China with active and passive samplings

The concentration of polychlorinated biphenyls (PCBs) in the urban air of Dalian, China was monitored from November 2009 to October 2010 with active high-volume sampler and semipermeable membrane device (SPMD) passive sampler. The concentration of PCBs (particle + gas) ( ∑ PCBs) ranged from 18.6 to 91.0 pg/m 3 , with an average of 50.9 pg/m 3 , and the most abundant dioxin-like PCB (DL-PCBs) was PCB118. The WHO-TEQ values of DL-PCBs were 3.6-22.1 fg/m3 , with an average of 8.5 fg/m 3 , and PCB126 was the maximum contributor to ∑ TEQ. There was a much larger amount of PCBs in the gas phase than in the particulate phase. The dominant PCB components were lower and middle molecular weight PCBs. With increasing chlorination level, the concentration of the PCB congeners in the air decreased. The gas-particulate partitioning of PCBs was different for the four seasons. The gas- particulate partitioning coefficients (logK p ) vs. subcooled liquid vapor pressures (logP L 0 ) of PCBs had reasonable correlations for different sampling sites and seasons. The absorption mechanism contributed more to the gas-particulate partitioning process than adsorption. Correlation analysis of meteorological parameters with the concentration of PCBs was conducted using SPSS packages. The ambient temperature and atmospheric pressure were important factors influencing the concentration of PCBs in the air. The distribution pattern of the congeners of PCBs and the dominant contributors to DL-PCBs and TEQ in active samples and SPMDs passive samples were similar. SPMD mainly sequestrated gas phase PCBs.     

Concordance between short-term experiments and long-term censuses in tide pool fishes

Sixteen years of annual censuses (1990-2005) of an assemblage of tide pool sculpins at Tatoosh Island, Washington, USA, revealed relative constancy in the numbers of recruits and adults. However, the dominant species as a recruit (Clinocottus globiceps) was always replaced numerically as an adult by another species (Oligocottus maculosus). When mechanisms of coexistence were evaluated, little support was found for either a lottery model, because competitive interactions are hierarchical, or a storage-effect model of coexistence, because the relative ranking of recruitment varied little among years and did not covary among species with environmental variables such as ocean temperature, upwelling indices, or an estimator of ocean productivity (oyster condition index). There was also little evidence of niche partitioning based on habitat affinities. Additionally, predation-mediated coexistence had little support, given that the competitive dominant did not have the greatest rates of mortality. Instead, a competition-colonization trade-off may contribute to the coexistence of these species, where C. globiceps always recruits in the greatest numbers, while O. maculosus dominates the adult assemblage via competitive processes. The importance of post-recruitment processes in this assemblage is further suggested by some negative associations among species, the presence of density dependence, some habitat affinities, and previously published experimental work that demonstrated the competitive dominance of O. maculosus over C globiceps.     

Antibiotika als Umweltkontaminanten — Effekte auf Bodenbakterien

Goal and scope

Among the human and veterinary pharmaceuticals, antibiotics form an important group. Recent research addressed the environmental ‘side effects’ of antibiotics. Evidence for environmental effects of antibiotics has for example been found for the respiratory activity of soil microorganisms. In the present contribution, results of studies on the ecotoxicology of antibiotics that are based on the utilization of carbon substrates in so-called Biolog plates are summarized.

Methods, Results and Conclusions

The method of pollution-induced community tolerance (PICT) takes centre stage. PICT is based on the changes in community composition of environmental communities brought about by a toxicant, which lead to an overall increase in community tolerance to this toxicant. The suitability of such an increase in community tolerance as ecotoxicological endpoint had been the subject of several experiments. It was shown that effect testing of antibiotics requires supplementation of the communities with nutrients, and that the PICT method reveals antibiotic effects with a high specificity. In an application of PICT, effects of three classes of antibacterial compounds were investigated. Dose-response relationships were obtained for all substances, and effect concentrations were partly in the range of expected environmental concentrations. The possible risks of antibiotic use for an increase in the occurrence of antibiotic resistance genes in the environment are also touched upon, including the extent of natural resistance.

Outlook

Due to its specificity, the PICT method has shown to be a suitable ecotoxicological assay. Due to possible effects of tetracyclines on the structure of the soil microbial community, it is advised to use veterinary antibiotics with caution. The risks of an increase in the occurrence of antibiotic resistance in the environment should be investigated in more detail.     

HERA: a Supermicroscope for Investigating the Structure of the Proton

   HERA, a high energy particle collider at the Deutsches Elektronensychrotron DESY in Hamburg, allows investigation of the structure of the proton with a spatial resolution of 10 cm, corresponding to about 1/1000 of its diameter. This view deep into the inner properties of matter is obtained from the scattering of high-energy electrons or positrons from high-energy protons. With its 6.3 km circumference, HERA can be regarded as a gigantic electron microscope. The high energies available at HERA allow a wealth of further studies on the properties of elementary particles and their interactions. After a brief review of earlier experiments, the article describes the concept of HERA and the detectors H1 and ZEUS, with which the scattering events are analyzed, as well as some of the physics results.     

Molecular prenatal diagnosis of Smith–Lemli–Opitz syndrome is reliable and efficient

Smith–Lemli–Opitz (RSH) syndrome (SLOS, OMIM 270400) is a relatively common, autosomal recessive disorder of cholesterol biosynthesis with a broad spectrum of phenotypic abnormalities caused by mutations of the 7-dehydrocholesterol reductase gene (DHCR7) on chromosome 11. Prenatal diagnosis can be established by detection of elevated 7-dehydrocholesterol or of SLOS-causing mutations in the DHCR7 gene. We report here our experience with molecular prenatal diagnosis of SLOS. Mutation analysis of the DHCR7 gene was performed in chorionic villus samples of 13 pregnancies of couples with a family history of SLOS and known SLOS genotypes. This approach is accurate and reliable. If facilities for biochemical analysis are not available, or in cases with ambiguous biochemical patterns, molecular prenatal diagnosis is an attractive, alternative option. Copyright © 2002 John Wiley & Sons, Ltd.