Reduced adsorption of caesium on clay minerals caused by various humic substances

The effect of the addition of various humic substances on the adsorption of caesium on two mineral clays has been studied. All measurements were carried out in dilute suspension under controlled conditions of temperature and ionic strength. Only a small proportion of the humic substance was adsorbed on the clays ((10%). In general, the anity of the clay}humic complexes for caesium was less than that of the bare clay. The decrease was greater for illite than for montmorillonite, and greatest at trace concentrations of caesium and increased with increasing concentration of each humic substance. However, no correlation was found between the amount of humic substance adsorbed and the decrease in Cs adsorption when all complexes were considered. Neither size nor the origin of the humic substances could explain the extent of the adsorption decrease. Since neither steric hindrance nor decrease in the number of adsorption sites was the driving force behind this phenomenon, it is hypothesized that the anity of the clay surface is modi"ed by the organic macromolecules. The highly selective frayed edge sites of illite are particularly sensitive to the adsorption of polyanions because of their proximity to anion adsorption sites. The observed decrease in Cs adsorption may contribute to the unexpectedly high bioavailability of Cs in organic soils

Possible role of organic matter in radiocaesium adsorption in soils

The aim of this review is to examine the hypothesis that organic matter decreases the adsorption of radiocaesium on clay minerals. The factors that determine radiocaesium mobility and bioavailability in soil are briefly outlined to show why a relationship between soil organic matter content and enhanced Cs bioavailability is paradoxical. In all the investigations reviewed the ionic compositions of both the solid and the solution phases have been strictly controlled. We show that the addition of organic matter to reference clay minerals causes decreases of up to an order of magnitude in the distribution coefficient of radiocaesium. Similarly, the chemical removal of organic matter from the clay-sized fraction of soil usually leads to an increase in Cs adsorption. We suggest that the nature of the organic matter and its interaction with mineral surfaces are as important as the amount present

Performance constraints and compensation for teleoperation with delay

A classical control perspective is used to characterize performance constraints and evaluate compensation techniques for teleoperation with delay. Use of control concepts such as open and closed loop performance, stability, and bandwidth yield insight to the delay problem. Teleoperator performance constraints are viewed as an open loop time delay lag and as a delay-induced closed loop bandwidth constraint. These constraints are illustrated with a simple analytical tracking example which is corroborated by a real time, 'man-in-the-loop' tracking experiment. The experiment also provides insight to those controller characteristics which are unique to a human operator. Predictive displays and feedforward commands are shown to provide open loop compensation for delay lag. Low pass filtering of telemetry or feedback signals is interpreted as closed loop compensation used to maintain a sufficiently low bandwidth for stability. A new closed loop compensation approach is proposed that uses a reactive (or force feedback) hand controller to restrict system bandwidth by impeding operator inputs

Biomarkers of inflammatory arthritis and proteomics

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Socioeconomic status, mastery, and goal-striving stress among rural youth

Although a growing body of research documents the links between goal-striving stress and emotional disorder, less research examines the psychosocial antecedents of goal-striving stress. Drawing on longitudinal survey data from a panel study of rural youth, this thesis examines the effects of socioeconomic status and mastery on educational goal-striving stress, occupational goal-striving stress, and combined goal-striving stress. Results indicate that each measure of goal-striving stress is not equally well predicted by socioeconomic status and mastery. Notably, the effects of socioeconomic status on occupational goal-striving stress and combined goal-striving stress are conditioned by mastery, while neither socioeconomic status nor mastery is associated with educational goal-striving stress. Findings show that the interaction between socioeconomic status and mastery accounts for socioeconomic status differences in both occupational and combined goal-striving stress, and that mastery is associated with a decrease in occupational and combined goal-striving stress particularly at lower socioeconomic strata

An ab-initio theoretical investigation of the soft-magnetic properties of permalloys

We study Ni80Fe20-based permalloys with the relativistic spin-polarized Korringa-Kohn-Rostoker electronic structure method. Treating the compositional disorder with the coherent potential approximation, we investigate how the magnetocrystalline anisotropy, K, and magnetostriction, lambda, of Ni-rich Ni-Fe alloys vary with the addition of small amounts of non-magnetic transition metals, Cu and Mo. From our calculations we follow the trends in K and lambda and find the compositions of Ni-Fe-Cu and Ni-Fe-Mo where both are near zero. These high permeability compositions of Ni-Fe-Cu and Ni-Fe-Mo match well with those discovered experimentally. We monitor the connection of the magnetic anisotropy with the number of minority spin electrons, Nmin. By raising Nmin via artificially increasing the band-filling of Ni80Fe20, we are able to reproduce the key features that underpin the magnetic softening we find in the ternary alloys. The effect of band-filling on the dependence of magnetocrystalline anisotropy on atomic short-range order in Ni80Fe20 is also studied. Our calculations, based on a static concentration wave theory, indicate that the susceptibility of the high permeability of the Ni-Fe-Cu and Ni-Fe-Mo alloys to their annealing conditions is also strongly dependent on the alloys' compositions. An ideal soft magnet appears from these calculations.Comment: 20 pages, 6 figure

The GDPR and the research exemption: considerations on the necessary safeguards for research biobanks

The General Data Protection Regulation (GDPR) came into force in May 2018. The aspiration of providing for a high level of protection to individuals’ personal data risked placing considerable constraints on scientific research, that was contrary to various research traditions across the EU. Therefore, along with the set of carefully outlined data subjects’ rights, the GDPR provides for a two-level framework to enable derogations from these rights when scientific research is concerned. First, by directly invoking provisions of the GDPR on a condition that safeguards that must include ‘technical and organisational measures’ are in place and second, through the Member State law. Although these derogations are allowed in the name of scientific research, they can simultaneously be challenging in light of the ethical requirements and well-established standards in biobanking that have been set forth in various research-related soft legal tools, international treaties and other legal instruments. In this paper we review such soft legal tools, international treaties and other legal instruments that regulate the use of health research data. We report on the results of this review, and analyse the rights contained within the GDPR and Article 89 of the GDPR vis-à-vis these instruments. These instruments were also reviewed to provide guidance on possible safeguards that should be followed when implementing any derogations. To conclude, we will offer some commentary on limits of the derogations under the GDPR and appropriate safeguards to ensure compliance with standard ethical requirements