The measurement and significance of ATP pools in activated sludge treating coke oven liquors

Coke oven liquor is a toxic wastewater produced in large quantities by the Iron and Steel, and Coking Industries, and gives rise to major effluent treatment problems in those industries. Conscious of the potentially serious environmental impact of the discharge of such wastes, pollution control agencies in many countries have made progressively more stringent quality requirements for the discharge of the treated waste. The most common means of treating the waste is the activated sludge process. Problems with achieving consistently satisfactory treatment by this process have been experienced in the past. The need to improve the quality of the discharge of the treated waste prompted attempts by TOMLINS to model the process using Adenosine Triphosophnte (ATP) as a measure of biomass, but these were unsuccessful. This thesis describes work that was carried out to determine the significance of ATP in the activated sludge treatment of the waste. The use of ATP measurements in wastewater treatment were reviewed. Investigations were conducted into the ATP behaviour of the batch activated sludge treatment of two major components of the waste, phenol, and thiocyanate, and the continuous activated sludge treatment of the liquor itself, using laboratory scale apparatus. On the basis of these results equations were formulated to describe the significance of ATP as a measured activity and biomass in the treatment system. These were used as the basis for proposals to use ATP as a control parameter in the activated sludge treatment of coke oven liquor, and wastewaters in general. These had relevance both to the treatment of the waste in the reactor and to the settlement of the sludge produced in the secondary settlement stage of the treatment process.

On the structural repertoire of pools of short, random RNA sequences

A detailed knowledge of the mapping between sequence and structure spaces in populations of RNA molecules is essential to better understand their present-day functional properties, to envisage a plausible early evolution of RNA in a prebiotic chemical environment and to improve the design of in vitro evolution experiments, among others. Analysis of natural RNAs, as well as in vitro and computational studies, show that certain RNA structural motifs are much more abundant than others, pointing out a complex relation between sequence and structure. Within this framework, we have investigated computationally the structural properties of a large pool (10 molecules) of single-stranded, 35 nt-long, random RNA sequences. The secondary structures obtained are ranked and classified into structure families. The number of structures in main families is analytically calculated and compared with the numerical results. This permits a quantification of the fraction of structure space covered by a large pool of sequences. We further show that the number of structural motifs and their frequency is highly unbalanced with respect to the nucleotide composition: simple structures such as stem-loops and hairpins arise from sequences depleted in G, while more complex structures require an enrichment of G. In general, we observe a strong correlation between subfamilies-characterized by a fixed number of paired nucleotides-and nucleotide composition. Our results are compared to the structural repertoire obtained in a second pool where isolated base pairs are prohibited. © 2008 Elsevier Ltd. All rights reserved.

A talent for living:exploring Ghana's 'new' urban childhood

This paper considers the lives of children living in a large informal settlement in central Accra, Ghana. Its contention is that children remain largely absent from the renewal of interest in slums and that where they do feature it is largely as objects of risk and vulnerability. Such an exclusive focus, it is argued, risks effacing the ways in which children are capable of actively confronting the terrible constraints posed by slum environments and the 'talent for living' that this involves. Drawing upon the findings of a small qualitative exploratory research project, the paper examines sources of support and cooperation between children and how their decisions to work are perceived as a strategy to actively support mothers and families struggling for a subsistence. © 2011 The Author(s). Children and Society © 2011 National Children's Bureau and Blackwell Publishing Limited.

Current issues in international HRM:alternative forms of assignments, careers and talent management in a global context

This special issue is dedicated to examining some current issues in international HRM; it contributes mainly to the field of HRM in the multinational enterprise. However, it clearly also draws on knowledge from cross-cultural IHRM. The guest editors have identified three topics that have gained tremendous importance due to the increasing globalisation of the world economy and the war for internationally qualified talent. This not only applies to multinational enterprises, but also to small and medium-sized enterprises, as senior managers are challenged to attract, retain, and motivate global talent: global assignments, global careers and global talent management. While all fields are not new and have partly been subject to prominent publications (e.g., Scullion & Collings, 2011; Cascio, 2013) new and highly relevant research questions continue to emerge and there is still a lack of empirical research in these areas.