Monitoring programme of Finnish arable land : agua regia extractable trace elements in cultivated soils in 1998

The main aim of this study was to produce internationally comparable knowledge on the status of cultivated soils in Finland. From the soil material collected during the latest sampling process under the national monitoring programme in 1998, 338 samples were selected for this investigation. The sampling sites were situated evenly over the whole cultivated area in Finland. Samples taken as four sub-samples from the plough layer were analysed for arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), selenium (Se), vanadium (V) and zinc (Zn) using aqua regia extraction according to an international standard method (ISO 11466). General statistical indicators of the analytical results of trace element concentrations are presented by soil type groups and by plant cultivation zones. Distributions of the results into the concentration classes are shown graphically and geographical distributions of the trace element concentrations are presented on the thematic maps

Total mercury concentrations in an industrialized catchment, the Thur River basin (north-eastern France): geochemical background level and contamination factors

River bottom sediments and soils were collected from the industrialized Thur River basin (north-eastern France) to assess mercury contamination. The regional geochemical background level of total mercury was evaluated to calculate mercury contamination factors (Fc) in soils and river bottom sediments. Our estimate of the mean background mercury levels in river sediments and soils, not affected by human activities, was 232 ng g1 (range: 27–406 ng g1). Sediments contaminated by the effluent from a chlor-alkali plant yielded the highest contamination factors (Fc¼1784). Contamination factors of surficial soils within 1 km of the industrial site range from 6.3 to 43.6. This contamination is attributed to diffuse atmospheric deposition from this local plant. However, even upstream from this industrial area elevated contamination factors were recorded for river bottom sediments (Fc¼3.2 to 26.4) and for one alluvial soil profile (Fc¼10). This is possibly due to past pollution resulting from waste water discharges. Mercury contamination in the different horizons of alluvial soils is not correlated with soil organic carbon content, but may be the result of occasional accidental pollution arising from the introduction of contaminated suspended particulate matter by the Thur River during periods of flooding

A grain size distribution model for non-catalytic gas-solid reactions

A new model to describe the non-catalytic conversion of a solid by a reactant gas is proposed. This so-called grain size distribution (GSD) model presumes the porous particle to be a collection of grains of various sizes. The size distribution of the grains is derived from mercury porosimetry measurements. The measured pore size distribution is converted into a grain size distribution through a so-called pore-tosphere factor whose value is also derived from the porosimetry measurements. The grains are divided into a number of size classes. For each class the conversion rate is calculated either according to the shrinking core model, involving core reaction and product layer diffusion as rate-determining steps or according to a new model in which some reaction at the grain surface is assumed to be limiting. The GSD model accounts for the phenomenon of pore blocking by calculating the maximum attainable conversion degree for each size class. In order to verify the model, two types of precalcined limestone particles with quite different microstructures were sulphided as well as sulphated. Furthermore, a single sample of sulphided dolomite was regenerated with a mixture of carbon dioxide and steam. For each reaction good agreement was attained between measured and simulated conversion vs. time behaviour

INPOP new release: INPOP13b

Based on the use of MESSENGER radiotracking data in the construction of new Mercury ephemerides (Verma et al. 2014) a new planetary ephemerides INPOP13b was built including Mercury improvements but also improvements on the Mars orbit and on the tie of INPOP planetary ephemerides to ICRF in general.Comment: INPOP sources available http://www.imcce.fr/inpo

Simple data analysis for biologists

This document provides a simple introduction to research methods and analysis tools for biologists or environmental scientists, with particular emphasis on fish biology in devleoping countries

The GENGA Code: Gravitational Encounters in N-body simulations with GPU Acceleration

We describe an open source GPU implementation of a hybrid symplectic N-body integrator, GENGA (Gravitational ENcounters with Gpu Acceleration), designed to integrate planet and planetesimal dynamics in the late stage of planet formation and stability analyses of planetary systems. GENGA uses a hybrid symplectic integrator to handle close encounters with very good energy conservation, which is essential in long-term planetary system integration. We extended the second order hybrid integration scheme to higher orders. The GENGA code supports three simulation modes: Integration of up to 2048 massive bodies, integration with up to a million test particles, or parallel integration of a large number of individual planetary systems. We compare the results of GENGA to Mercury and pkdgrav2 in respect of energy conservation and performance, and find that the energy conservation of GENGA is comparable to Mercury and around two orders of magnitude better than pkdgrav2. GENGA runs up to 30 times faster than Mercury and up to eight times faster than pkdgrav2. GENGA is written in CUDA C and runs on all NVIDIA GPUs with compute capability of at least 2.0.Comment: Accepted by ApJ. 18 pages, 17 figures, 4 table