Lennart Sjöberg

Newspaper reporting of hazards in the UK and Sweden

Public understanding of risks is likely to be informed by the media. We report a cross-national study looking at how newspapers in Sweden and the United Kingdom characterize a variety of risks, focusing on two months around the 10th anniversary of the Chernobyl accident. Approximately four times as many reports about risks were found in Sweden as in the U.K., possibly reflecting a Swedish safety culture. The Bovine Spongiform Encephalopathy (BSE) crisis dominated reporting in both countries, especially in the U.K. The proportion and pattern of reports on Chernobyl was similar across countries. However, in Sweden, there was an increase in reports about other nuclear hazards after the anniversary, suggesting that generalization of media concern may have occurred. Generally, BSE was discussed using a greater number of characterizations in the U.K., while Chernobyl was reported using more characterizations in Sweden. Reports about hazards tended to be alarmist rather than reassuring, and rarely used statistics to express degrees of risk.

Near-surface composition of acid-leached labradorite investigated by SIMS

Abstract The composition of the near-surface of acid-leached labradorite was investigated by depth-profiling with secondary ion mass spectrometry for H, D, O, Na, Al, Si, Cl, and Ca. Specimens were leached at room temperature at pH 1 for 500 h, and pH 2 and 3 for 1200 h, in solutions acidified with HCl. Complete leaching of Na, Ca, and Al occurred to a depth of 100 nm after 1200 h of reaction at pH 3 and produced sigmoidal depletion/concentration profiles. Depletion depths of these cations are shown to increase further with H + -activity and time. The presented element profiles, therefore, represent non-steady-state conditions. Calcium is removed from between 10 and 30 nm deeper within a single profile than the corresponding Al depletion depth. After removal of Na + and Ca + , a sequence of reaction steps results in preferential leaching of Al over Si and formation of silanol groups around the tetrahedral vacancy. This is immediately followed by spontaneous condensation of adjacent silanol groups, which eliminates a fraction of oxygen from the leached layer. The O/Si ratio of the residual structure is thus reduced, and a high degree of cross-linkage between Si-tetrahedra is maintained. Throughout the leached layer, the O/Si atomic ratio is reduced from 3.3 (fresh labradorite) to values between 2.5 and 2.0. The leached layer is enriched in H in all specimens, with average concentration plateus of about 7·10 21 atoms/cm 3 , or 11 at%, if the leached layer is assumed to have a density equal to amorphous SiO 2 . At the time of analysis the leached layer is anhydrous and composed solely of H, Si, and O. The H concentrations are in accord with an O/Si atomic ratio of 2.2 in terms of charge balance. The analytical composition corresponds to SiO 1.8 (OH) 0.4 . Good agreement between leaching depths determined by SIMS profiling and as calculated from element release rates during kinetic dissolution experiments suggests that the sites for ion-exchange and depolymerization reactions are uniformly distributed over the entire mineral surface, and that any changes in reactive surface area have been small during these experiments.

Quantum chemical studies of the effects on silicate mineral dissolution rates by adsorption of alkali metals

Quantum chemical calculations at the density functional level (B3LYP functional) with full geometry optimisation have been performed on the effect of protonation and of adsorption of alkali cations (Li+, Na+, K+, Rb+, and Cs+) on the siloxane bond strength in silicate minerals. The influence of pH was modelled by assuming a fully protonated surface model, (OH)3SiOSi(OH)3, at pH lower than the point of zero charge (pzc), while for pH = pzc and pH > pzc, the cation was assumed to interact with a deprotonated surface -O− site. At low pH, addition of cations is found to strengthen the siloxane bond in agreement with experiment for the alkali metals, but not for the interaction with H3O+. At high pH, the siloxane bond is weakened by the addition of alkali, in agreement with experiment for feldspar dissolution. Inclusion of the surface hydroxyl groups is found to be important particularly when solvation of the ions at the surface is considered; up to three water molecules have been included in the geometry optimisation. Solvation of the ions interacting with the surface is found to give very important contributions to the computed reaction energies.

Successive intervals scaling of paired comparisons

In this paper a method is developed for analyzing data resulting from the use of a modification of the usual paired comparisons procedure which allows for ratings of size of difference. The scaling model is essentially an extension of the Thurstonian successive intervals model. The method is applied to scaling of a set of nine “immoral” actions and the results agree rather well with those from conventional successive intervals scaling of the same stimuli.

A method for sensation scaling based on an analogy between perception and judgment

Two techniques for studying judgment are discussed. In the first of these one assumes invariance of perception over different judgment processes and conceives of the properties of one judgment process as known. Then, perceptions may be estimated under this process and utilized in the study of other judgment processes of interest. A second technique disposes of the reliance up on a basic, “known” process and instead suggests that perception be treated as free parameters to be estimated from data. The paper then proceeds to show how this second technique may be used under certain conditions on perception themselves. A concept of sensation is introduced which is thought of as generating percepts in formally the same manner as percepts are thought of as generating judgments. The idea is tried out on the perception of movement time. A simple perception process appears to give a good fit to data.