The economic geology of the Okiep copper deposits, Namaqualand, South Africa

The Okiep Copper District situated in the north-western Cape Province, covers some 3 000 km and is the oldest mining area in the Republic of South Africa. The O'okiep Copper Company Limited commenced production in 1940 with a proven ore reserve of 9 million tons at 2,45 % cu. Production since 1940 and present ore reserves total some 93 million tonnes at 1,08 % Cu. The rocks comprising the Okiep Copper District are of Proterozoic age and have been subdivided into a meta-volcanosedimentary succession, intruded by various sub-horizontally emplaced granitoid intrusions. The various intrusions occurred at different stages relative to the main structural and metamorphic events. The copper deposits are confined to basic rocks which are the youngest major group of intrusives in the District. They occur as swarms of generally easterly-trending, steep northdipping, irregular dyke-like bodies consisting of diorite, anorthosite and norite. The dominant silicate constituents are andesite ranging to labradorite, hypersthene, biotite and phlogopite. Copper sulphides are preferentially associated with the more basic varieties. The copper sulphides are mainly chalcopyrite, bornite and subsidiary chalcocite. The copper content of the basic rocks is erratic ranging over small distances from a mere trace to several percent. Emplacement of the cupriferous basic rocks is predisposed to a large extent by enigmatic structural features locally referred to as steep structures. The most common manifestation of steep structure deformation is typically a narrow antiformal linear feature along which continuity of the country rocks has been interrupted by piercement folding and shearing. In places, pipelike bodies of megabreccia occur along steep structures, and also act as hosts to the basic rock. Areas of steep structure are thus prime exploration targets, due to their close spatial association with the cupriferous basic rocks. Exploration techiques employed in the Okiep Copper District in~ elude regional and detailed geological mapping, geophysical surveys utilizing magnetic, gravimetric and electrical methods, as well as limited application of soil and stream-sediment geochemistry. Final evaluation is by surface and underground diamond drilling. Exploration has to date discovered 18 new mines with individual ore reserves ranging from 200 000 to 37 000 000 tonnes. All are underground operations, and the sub-level open stoping method of mining is standard

Chemical genetic identification of CDKL5 substrates reveals its role in neuronal microtubule dynamics.

Loss-of-function mutations in CDKL5 kinase cause severe neurodevelopmental delay and early-onset seizures. Identification of CDKL5 substrates is key to understanding its function. Using chemical genetics, we found that CDKL5 phosphorylates three microtubule-associated proteins: MAP1S, EB2 and ARHGEF2, and determined the phosphorylation sites. Substrate phosphorylations are greatly reduced in CDKL5 knockout mice, verifying these as physiological substrates. In CDKL5 knockout mouse neurons, dendritic microtubules have longer EB3-labelled plus-end growth duration and these altered dynamics are rescued by reduction of MAP1S levels through shRNA expression, indicating that CDKL5 regulates microtubule dynamics via phosphorylation of MAP1S. We show that phosphorylation by CDKL5 is required for MAP1S dissociation from microtubules. Additionally, anterograde cargo trafficking is compromised in CDKL5 knockout mouse dendrites. Finally, EB2 phosphorylation is reduced in patient-derived human neurons. Our results reveal a novel activity-dependent molecular pathway in dendritic microtubule regulation and suggest a pathological mechanism which may contribute to CDKL5 deficiency disorder

Integration of professional judgement and decision-making in high-level adventure sports coaching practice

This study examined the integration of professional judgement and decision-making processes in adventure sports coaching. The study utilised a thematic analysis approach to investigate the decision-making practices of a sample of high-level adventure sports coaches over a series of sessions. Results revealed that, in order to make judgements and decisions in practice, expert coaches employ a range of practical and pedagogic management strategies to create and opportunistically use time for decision-making. These approaches include span of control and time management strategies to facilitate the decision-making process regarding risk management, venue selection, aims, objectives, session content, and differentiation of the coaching process. The implication for coaches, coach education, and accreditation is the recognition and training of the approaches that“create time” for the judgements in practice, namely“creating space to think”. The paper concludes by offering a template for a more expertise-focused progression in adventure sports coachin

A trigger-substrate model for smiling during an automated formative quiz: engagement is the substrate, not frustration

INTRODUCTION: Automated tutoring systems aim to respond to the learner’s cognitive state in order to maintain engagement. The end-user’s state might be inferred by interactive timings, bodily movements or facial expressions. Problematic computerized stimuli are known to cause smiling during periods of frustration. METHODS: Forty-four seated, healthy participants (age range 18-35, 18 male) used a handheld trackball to answer a computer-presented, formative, 3-way multiple choice geography quiz, with 9 questions, lasting a total of 175 seconds. Frontal facial videos (10 Hz) were collected with a webcam and processed for facial expressions by CrowdEmotion using a pattern recognition algorithm. Interactivity was recorded by a keystroke logger (Inputlog 5.2). Subjective responses were collected immediately after each quiz using a panel of visual analogue scales (VAS). RESULTS: Smiling was fie-fold enriched during the instantaneous feedback segments of the quiz, and this was correlated with VAS ratings for engagement but not with happiness or frustration. Nevertheless, smiling rate was significantly higher after wrong answers compared to correct ones, and frustration was correlated with the number of questions answered incorrectly. CONCLUSION: The apparent disconnect between the increased smiling during incorrect answers but the lack of correlation between VAS frustration and smiles suggests a trigger-substrate model where engagement is the permissive substrate, while the noises made by the quiz after wrong answers may be the trigger

Managing affect in learners' questions in undergraduate science

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Society for Research into Higher Education.This article aims to position students' classroom questioning within the literature surrounding affect and its impact on learning. The article consists of two main sections. First, the act of questioning is discussed in order to highlight how affect shapes the process of questioning, and a four-part genesis to question-asking that we call CARE is described: the construction, asking, reception and evaluation of a learner's question. This work is contextualised through studies in science education and through our work with university students in undergraduate chemistry, although conducted in the firm belief that it has more general application. The second section focuses on teaching strategies to encourage and manage learners' questions, based here upon the conviction that university students in this case learn through questioning, and that an inquiry-based environment promotes better learning than a simple ‘transmission’ setting. Seven teaching strategies developed from the authors' work are described, where university teachers ‘scaffold’ learning through supporting learners' questions, and working with these to structure and organise the content and the shape of their teaching. The article concludes with a summary of the main issues, highlighting the impact of the affective dimension of learning through questioning, and a discussion of the implications for future research

Muonium as a hydrogen analogue in silicon and germanium; quantum effects and hyperfine parameters

We report a first-principles theoretical study of hyperfine interactions, zero-point effects and defect energetics of muonium and hydrogen impurities in silicon and germanium. The spin-polarized density functional method is used, with the crystalline orbitals expanded in all-electron Gaussian basis sets. The behaviour of hydrogen and muonium impurities at both the tetrahedral and bond-centred sites is investigated within a supercell approximation. To describe the zero-point motion of the impurities, a double adiabatic approximation is employed in which the electron, muon/proton and host lattice degrees of freedom are decoupled. Within this approximation the relaxation of the atoms of the host lattice may differ for the muon and proton, although in practice the difference is found to be slight. With the inclusion of zero-point motion the tetrahedral site is energetically preferred over the bond-centred site in both silicon and germanium. The hyperfine and superhyperfine parameters, calculated as averages over the motion of the muon, agree reasonably well with the available data from muon spin resonance experiments.Comment: 20 pages, including 9 figures. To appear in Phys. Rev.

The landscape of gifted and talented education in England and Wales: How are teachers implementing policy?

This is an Author's Accepted Manuscript of an article published in Research Papers in Education, 27(2), 167-186, 2012, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/02671522.2010.509514.This paper explores the evidence relating to how primary schools are responding to the ‘gifted and talented’ initiative in England and Wales. A questionnaire survey which invited both closed and open-ended responses was carried out with a national sample of primary schools. The survey indicated an increasing proportion of coordinators, compared with a survey carried out in 1996, were identifying their gifted and talented children as well as having associated school policies. However, the survey also highlighted a number of issues which need addressing if the initiative is to achieve its objective of providing the best possible educational opportunities for children. For example, it was found that a significant number of practitioners were not aware of the existence of the National Quality Standards for gifted and talented education, provided by the UK government in 2007, and the subject-specific criteria provided by the UK’s Curriculum Authority for identification and provision have been largely ignored. The process of identifying children to be placed on the ‘gifted and talented’ register seems haphazard and based on pragmatic reasons. Analysis of teachers’ responses also revealed a range of views and theoretical positioning held by them, which have implications for classroom practice. As the ‘gifted and talented’ initiative in the UK is entering a second decade, and yet more significant changes in policy are introduced, pertinent questions need to be raised and given consideration

Cost-effectiveness of adjunct non-pharmacological interventions for osteoarthritis of the knee

BACKGROUND: There is limited information on the costs and benefits of alternative adjunct non-pharmacological treatments for knee osteoarthritis and little guidance on which should be prioritised for commissioning within the NHS. This study estimates the costs and benefits of acupuncture, braces, heat treatment, insoles, interferential therapy, laser/light therapy, manual therapy, neuromuscular electrical stimulation, pulsed electrical stimulation, pulsed electromagnetic fields, static magnets and transcutaneous electrical nerve Stimulation (TENS), based on all relevant data, to facilitate a more complete assessment of value. METHODS: Data from 88 randomised controlled trials including 7,507 patients were obtained from a systematic review. The studies reported a wide range of outcomes. These were converted into EQ-5D index values using prediction models, and synthesised using network meta-analysis. Analyses were conducted including firstly all trials and secondly only trials with low risk of selection bias. Resource use was estimated from trials, expert opinion and the literature. A decision analytic model synthesised all evidence to assess interventions over a typical treatment period (constant benefit over eight weeks or linear increase in effect over weeks zero to eight and dissipation over weeks eight to 16). RESULTS: When all trials are considered, TENS is cost-effective at thresholds of £20-30,000 per QALY with an incremental cost-effectiveness ratio of £2,690 per QALY vs. usual care. When trials with a low risk of selection bias are considered, acupuncture is cost-effective with an incremental cost-effectiveness ratio of £13,502 per QALY vs. TENS. The results of the analysis were sensitive to varying the intensity, with which interventions were delivered, and the magnitude and duration of intervention effects on EQ-5D. CONCLUSIONS: Using the £20,000 per QALY NICE threshold results in TENS being cost-effective if all trials are considered. If only higher quality trials are considered, acupuncture is cost-effective at this threshold, and thresholds down to £14,000 per QALY