Simple Lattice-Models of Ion Conduction: Counter Ion Model vs. Random Energy Model

The role of Coulomb interaction between the mobile particles in ionic conductors is still under debate. To clarify this aspect we perform Monte Carlo simulations on two simple lattice models (Counter Ion Model and Random Energy Model) which contain Coulomb interaction between the positively charged mobile particles, moving on a static disordered energy landscape. We find that the nature of static disorder plays an important role if one wishes to explore the impact of Coulomb interaction on the microscopic dynamics. This Coulomb type interaction impedes the dynamics in the Random Energy Model, but enhances dynamics in the Counter Ion Model in the relevant parameter range.Comment: To be published in Phys. Rev.

Contributions to the mixed-alkali effect in molecular dynamics simulations of alkali silicate glasses

The mixed-alkali effect on the cation dynamics in silicate glasses is analyzed via molecular dynamics simulations. Observations suggest a description of the dynamics in terms of stable sites mostly specific to one ionic species. As main contributions to the mixed--alkali slowdown longer residence times and an increased probability of correlated backjumps are identified. The slowdown is related to the limited accessibility of foreign sites. The mismatch experienced in a foreign site is stronger and more retarding for the larger ions, the smaller ions can be temporarily accommodated. Also correlations between unlike as well as like cations are demonstrated that support cooperative behavior.Comment: 10 pages, 12 figures, 1 table, revtex4, submitted to Phys. Rev.

The Roles of Experts and Expert-Based Information in the Advocacy Coalition Framework: Conceptual and Empirical Considerations Based on the Acid Mine Drainage Case Study in Gauteng, South Africa

The Advocacy Coalition Framework (ACF) remains one of the leading conceptual models in the policy sciences because it continues to be revised and updated as required. A focus area of the ACF that requires further theorization is the roles of experts and expert-based information in influencing policy problem contexts. Our article takes a necessary step in this direction by (1) evaluating the usefulness of Weible’s expectations regarding the uses of expert-based information in different types of policy subsystems and factors that contribute to shifts from one subsystem to another; and (2) making critical observations that result from this evaluation in the context of the controversial acid mine drainage policy case study in South Africa. The findings of our case study analysis indicate that Weible’s framework performed reasonably well but also revealed opportunities for further improvement. We therefore suggest adding awareness raising as a use of expert-based information, developing a typology of different types of experts who participate in policy subsystems, and including a focus on the use of expert-based information in policy subsystem shifts. We also reflect upon the relevance and importance of continuing to expand ACF applications to countries outside of North America and Western Europe

IDENTITY POLITICS AND NIGERIAN 2015 PRESIDENTIAL ELECTIONS: A DISCOURSE ANALYSIS OF FEEDBACK COMMENTS ON SELECTED ONLINE REPORTS OF POLITICAL ISSUES

Interactive media platform provides greater access to information and greater opportunity to express thoughts and opinions. It also provides insight in to people’s state of mind, their ideologies and beliefs on issues which they make comments about. Usage of words, manner of expression and language pattern are indicative of people’s motives and beliefs on national conversations. This study examines the readers’ comments on Nigerian online news reports with the aim of understanding readers’ attitudes on political issues during 2015 presidential elections. Since the readers’ comments are anonymous most times and because many people do not use their true identity, they provide insight into the true state of people’s mind, beliefs and attitudes and the implications of these on the corporate existence of Nigeria as a nation. Using discourse analysis approach, data comprising 45 comments which were online readers’ feedbacks from The Punch, Vanguard, Sahara Reporters and Premium Times based on two political issues were analysed. These issues are the postponement of 2015 presidential elections often regarded as the Polls Shift and Buhari’s certificate crisis. Findings reveal that readers are largely divided along ethnic, religious and political parties’ affiliations. Besides, hate comments pervade the feedbacks, an indication of politics of bitterness in practise in Nigeria. It is therefore necessary that mechanism is put in place to ensure that readers’ comments are not used to cause disaffection among the citizenry but rather for viable, rational and robust discussion that will deepen our democratic practices. Similarly, Nigerian government needs to work to ensure true integration among the various divides that make up the entity called Nigeria and also ensure good governance to avoid people’s hatred

BET Surface Area Determination of Calcium Oxide from Adamawa Chalk Mineral Using Water Adsorption Method, for Use as Catalyst.

This paper describes a test procedure for determining the total surface area of chalk mineral using the water adsorption method. The test involves saturating the thermally treated chalk sample with saturated salt solution of known relative humidity, until the water vapor forms a monomolecular layer on the treated chalk sample surface. The results of the test are expressed as Specific Surface Area (SSA), which describes the surface area/unit mass of dry treated sample with units of m2g-1. The test results presented demonstrate the BET isotherm of chalk samples after being thermally treated at 700, 900, 1100 and 1200oC. Results for a number of different treated chalk samples are presented. The proposed method uses simple and inexpensive laboratory equipment, is relatively simple to perform, and allows for rapid determination of SSA. Keywords: specific surface area, chalk mineral, water vapor, BET isother

Application of the adjoint approach to optimise the initial conditions of a turbidity current with the AdjointTurbidity 1.0 model

Turbidity currents are one of the main drivers of sediment transport from the continental shelf to the deep ocean. The resulting sediment deposits can reach hundreds of kilometres into the ocean. Computer models that simulate turbidity currents and the resulting sediment deposit can help us to understand their general behaviour. However, in order to recreate real-world scenarios, the challenge is to find the turbidity current parameters that reproduce the observations of sediment deposits. This paper demonstrates a solution to the inverse sediment transportation problem: for a known sedimentary deposit, the developed model reconstructs details about the turbidity current that produced the deposit. The reconstruction is constrained here by a shallow water sediment-laden density current model, which is discretised by the finite-element method and an adaptive time-stepping scheme. The model is differentiated using the adjoint approach, and an efficient gradient-based optimisation method is applied to identify the turbidity parameters which minimise the misfit between the modelled and the observed field sediment deposits. The capabilities of this approach are demonstrated using measurements taken in the Miocene Marnoso-arenacea Formation (Italy). We find that whilst the model cannot match the deposit exactly due to limitations in the physical processes simulated, it provides valuable insights into the depositional processes and represents a significant advance in our toolset for interpreting turbidity current deposits

Aureobacterium resistens sp. nov., exhibiting vancomycin resistance and teicoplanin susceptibility

Two similar strains of a coryneform bacterium were isolated from human clinical material. Both strains were resistant to vancomycin but susceptible to teicoplanin. Detailed biochemical, chemotaxonomical, and molecular genetic investigations revealed that both isolates were members of a hitherto undescribed species of the genus Aureobacterium. The name Aureobacterium resistens sp. nov. is proposed for the new bacterium and the type strain is CCUG 3831

Corynebacterium lipophiloflavum sp. nov. isolated from a patient with bacterial vaginosis

A unique coryneform bacterium was isolated from a patient with bacterial vaginosis. Chemotaxonomical investigations demonstrated that the unknown bacterium belonged to the genus Corynebacterium. The yellow-pigmented, slightly lipophilic, oxidative, urea-hydrolyzing bacterium could be phenotypically readily differentiated from the other members of the genus Corynebacterium. Comparative 16S rRNA gene analysis revealed that the bacterium represented a new subline within the genus Corynebacterium for which the name Corynebacterium lipophiloflavum sp. nov. is proposed. The type strain is CCUG 37336 (DSM 44291