Coccoliths and oxygen isotope observations from the sediment surface of the southwest Indian Ocean

The interplay of three important parameters, dissolution, dilution and winnowing seem to be controlling the state in which sediment material is preserved in the study area though most samples examined under the SEM were generally well preserved. The distribution of forty-four coccolithophore species in one hundred deep sea core-tops from the southwest Indian Ocean is described. Three coccolith assemblages have been recognised (Maputo, Agulhas Current and deep water) and are delineated by the relative abundances of four ecologically significant coccolithophore species (Gephyrocapsa oceanica, Emiliania huxleyi, Calcidiscus leptoporus and Umbilicosphaera sibogae). These four species are the most abundant in the study area and the major factors influencing their geographical distribution seem to be temperature, nutrient concentration and dissolution. Coccolith and foraminifera preservations indicate that the carbonate lysocline lies somewhere between 3500 and 4000 meters, resulting in the concentration of dissolution resistant microfossils below this depth. Stable oxygen isotope ratios in a planktonic foraminifera and percent abundances of E. huxleyi reveal that apart from cores taken in the Agulhas Passage, most of the core-top samples are probably less than 85,000 yrs. BP. Lightest isotope ratios of -1.5 to -1.0 per mil PDB (equal to 22.8 to 25.1°C) occur in a narrow band on the sea floor beneath the "A" route of the Agulhas Current. These values are about 0.5 per mil PDB lighter than samples analyzed on either side of this band and can be explained by the Agulhas Current's elevated temperature at the ocean surface of between 2 to 3°C. Thus, an oxygen isotope imprint of the Agulhas Current exists beneath it on the sea floor. The Agulhas Current is probably the major factor influencing sedimentation, sediment distribution patterns and geological features in the study area. At present it is voluminous and fast flowing, possibly eroding sediments 2500 meters below the surface. The oxygen-isotope ratios and nannoplankton counts obtained in this study indicate however, that the majority of samples are most probably recent or at least not older than 85,000 years except for sediments found in the Agulhas Passage. This implies that sediments are accumulating on the ocean floor and that the current does not have a pronounced erosional influence, at least in areas from which cores were retrieved for this study

Further properties of the i (en-am-1) mutant

Further properties of the i (en-am-1) mutan

Review of the regulation of veterinary drugs and residues in South Africa

Published ArticleThe food safety risk analysis framework of the FAO/WHO is used in the review of veterinary drug and residue regulation in South Africa to determine possible inefficiencies within this system. Results indicate that a variety of challenges relating to the processes of risk assessment, management, and communication do exist, although these occur within a fragmented system of legislation, functions, and structures. Addressing these challenges therefore requires a change to a more collaborative and integrated system. It is indicated that for such a change, the underlying challenges of inadequate horizontal communication, poor conceptualization, and awareness of functions of the system are required to be dealt with

Neurospora crassa suppressors act on amber

Neurospora crassa suppressors act on ambe

Developing an extended curriculum for humanities at the University of KwaZulu-Natal : conceptual shifts, challenges and constraints

Published ArticleThis article traces the early development and implementation of an extended curriculum in the Faculty of Humanities, Development and Social Sciences at the University of KwaZulu-Natal. Following Volbrecht and Boughey (2004) and Boughey (2007), it analyses the programme in the context of the development of Academic Development over two decades. The programme represents a conceptual shift from a foundation year model to a more holistic, integrated intervention which extends to the end of the second year. Prompted primarily by pedagogical and academic considerations, it is also a response to increasing emphasis on throughput and success and to the need to increase and enhance efficiency in Higher Education. The tension between the potential benefits of such a curriculum and challenges and constraints impacting on it is discussed in an attempt to develop a curriculum which is sustainable and which will result in higher success rates and the wider transformation of the curriculum

The development of sociology first degree courses at English universities, 1907-1972

A descriptive historical account of the development of sociology first degree courses at English universities, 1907-1972, begins with the background to the endowment, in 1907, of the first chairs of sociology, at the London School of Economics. The archives of the School, and of the University of London, are drawn upon in describing sociology in the early London BSc Economics and BA/BSc Sociology. An outline follows of university development, and of sociology degree structure at English universities, from 1946 onwards. Examples of lecture and seminar programmes and reading lists for sociology undergraduate courses, provided by university sociology departments, are used, with published material, to delineate sociology degree structure, 1963-1972, at six groups of institutions: ancient universities; constituent colleges of London university; older civic universities; younger civic universities; new universities; technological universities. Subject-matter in sociology degrees, 1963-1972, is discussed under five core subjects (Sociological Theory, Methods, Comparative Social Institutions, Social Structure of Modern Britain, Social Psychology) and nineteen optional subjects (Social Anthropology, Social Administration, Social Philosophy, Industrial Sociology, Political Sociology, the Sociology of Deviance, of Religion,and of Education, Urban Sociology, Demography, Race Relations, Sociology of the Family, Social Stratification, and the Sociology of Medicine, of Development, of Revolutions-of Knowledge, of Science, and of Culture Technological universities were less likely to have specialised sociology, and more likely to have sandwich, degrees; otherwise, no clear relationship: - emerged between type of university and type of sociology degree. Individual lecturers, with some exceptions, were chief decision-makers in selection of detailed course subject-matter. The main changes over time were: inclusion of more empirical studies; 'real world' events reflected in courses; sociology regarded as a liberal education. Sociology attained status as an academic discipline in a piecemeal fashion, and was in a transitional stage in universities in 1972. Questions for future research are suggested

Molecular dynamics simulations of elementary chemical processes in liquid water using combined density functional and molecular mechanics potentials. II. Charge separation processes

A new approach to carry out molecular dynamics simulations of chemical reactions in solution using combined density functional theory/molecular mechanics potentials is presented. We focus our attention on the analysis of reactive trajectories, dynamic solvent effects and transmission coefficient rather than on the evaluation of free energy which is another important topic that will be examined elsewhere. In a previous paper we have described the generalities of this hybrid molecular dynamics method and it has been employed to investigate low energy barrier proton transfer process in water. The study of processes with activation energies larger than a few kT requires the use of specific techniques adapted to “rare events” simulations. We describe here a method that consists in the simulation of short trajectories starting from an equilibrated transition state in solution, the structure of which has been approximately established. This calculation is particularly efficient when carried out with parallel computers since the study of a reactive process is decomposed in a set of short time trajectories that are completely independent. The procedure is close to that used by other authors in the context of classical molecular dynamics but present the advantage of describing the chemical system with rigorous quantum mechanical calculations. It is illustrated through the study of the first reaction step in electrophilic bromination of ethylene in water. This elementary process is representative of many charge separation reactions for which static and dynamic solvent effects play a fundamental [email protected]

Forced Stratified Turbulence: Successive Transitions with Reynolds Number

Numerical simulations are made for forced turbulence at a sequence of increasing values of Reynolds number, R, keeping fixed a strongly stable, volume-mean density stratification. At smaller values of R, the turbulent velocity is mainly horizontal, and the momentum balance is approximately cyclostrophic and hydrostatic. This is a regime dominated by so-called pancake vortices, with only a weak excitation of internal gravity waves and large values of the local Richardson number, Ri, everywhere. At higher values of R there are successive transitions to (a) overturning motions with local reversals in the density stratification and small or negative values of Ri; (b) growth of a horizontally uniform vertical shear flow component; and (c) growth of a large-scale vertical flow component. Throughout these transitions, pancake vortices continue to dominate the large-scale part of the turbulence, and the gravity wave component remains weak except at small scales.Comment: 8 pages, 5 figures (submitted to Phys. Rev. E

Assertive outreach treatment versus care as usual for the treatment of high-need, high-cost alcohol related frequent attenders: study protocol for a randomised controlled trial

Background: Alcohol-related hospital admissions have doubled in the last ten years to >1.2m per year in England. High-need, high-cost (HNHC) alcohol-related frequent attenders (ARFA) are a relatively small subgroup of patients, having multiple admissions or attendances from alcohol during a short time period. This trial aims to test the effectiveness of an assertive outreach treatment (AOT) approach in improving clinical outcomes for ARFA, and reducing resource use in the acute setting. Methods: One hundred and sixty ARFA patients will be recruited and following baseline assessment, randomly assigned to AOT plus care as usual (CAU) or CAU alone in equal numbers. Baseline assessment includes alcohol consumption and related problems, physical and mental health comorbidity and health and social care service use in the previous 6 months using standard validated tools, plus a measure of resource use. Follow-up assessments at 6 and 12months after randomization includes the same tools as baseline plus standard measure of patient satisfaction. Outcomes for CAU+AOT and CAU at 6 and 12months will be compared, controlling for pre-specified baseline measures. Primary outcome will be percentage of days abstinent at 12months. Secondary outcomes include emergency department (ED) attendance, number and length of hospital admissions, alcohol consumption, alcohol-related problems, other health service use, mental and physical comorbidity 6 and 12months post intervention. Health economic analysis will estimate the economic impact of AOT from health, social care and societal perspectives and explore cost-effectiveness in terms of quality adjusted life years and alcohol consumption at 12-month follow-up. Discussion: AOT models piloted with alcohol dependent patients have demonstrated significant reductions in alcohol consumption and use of unplanned National Health Service (NHS) care, with increased engagement with alcohol treatment services, compared with patients receiving CAU. While AOT interventions are costlier per case than current standard care in the UK, the rationale for targeting HNHC ARFAs is because of their disproportionate contribution to overall alcohol burden on the NHS. No previous studies have evaluated the clinical and costeffectiveness of AOT for HNHC ARFAs: this randomized controlled trial (RCT) targeting ARFAs across five South London NHS Trusts is the first. Trial registration: International standard randomized controlled trial number (ISRCTN) registry: ISRCTN67000214, retrospectively registered 26/11/2016