Dynamic process modelling of the HPS2 solar thermal molten salt parabolic trough test facility

In recent years power generation from renewable energy has grown substantially both in South Africa and around the world. This growth is set to continue as there is more pressure to reduce the burning of fossil fuels. However, renewable energy power generation suffers from unpredictability, which causes problems when it comes to managing power grids. Concentrated Solar Power (CSP) plants offer a practical solution to store power in the form of thermal energy storage (TES). Thus, the plant can run when there is no solar energy available, leading to a more stable power supply. Unfortunately, CSP plants cost more than other renewables such as photovoltaic and wind power. Thus, there is a need for research into how to bring down the cost of CSP plants. One of the most proven types of CSP is the parabolic trough plant. The most recent innovation is to try and use molten salt as the heat transfer fluid which would reduce the cost of the plant. However, this new technology has not been implemented on a full scale CSP plant and little testing has been done to prove the technology. The HPS2 is a test facility aimed at testing the use of molten salt as a heat transfer fluid (HTF). This test facility, located in Evora Portugal, is being developed by an international consortium led by the German DLR institute of Solar Research. It is one of the first test facilities of its kind where experiments will be conducted to demonstrate the validity of using molten salt as a HTF and a storage medium in a parabolic trough CSP plant. The HPS2 test facility is not yet operational and there is a need for a dynamic thermofluid process model to better understand and predict both its steady state and transient operational behaviour. This dissertation reports on the development of such a dynamic thermofluid process model and the results obtained from it. The process model developed primarily focuses on the steam cycle with the TES incorporated into the model. The physical geometry of each of the components are employed to construct discretized elements for which the conservation of mass, energy, and momentum are applied in a one-dimensional network approach. The economizer and evaporator combined has a helical coil geometry and uses molten salt as a heat transfer fluid, which is unique. Thus, correlations had to be adjusted for the flow characteristics found in the economizer/evaporator. Results from the steady state simulations of the steam cycle show that the molten salt mass flowrate through the steam generation system will have to be reduced from the initially expected value to meet operational requirements. Results of the dynamic simulations show that the test facility will be able to produce a constant power supply despite transient solar conditions and highlights key dynamic responses for operators to be aware of

Methylphenidate (Ritalin) use and abuse

No Abstrac

"A calming down game" : an IPA study exploring the use of biofeedback software to support individuals in 'managing feelings'.

This research examines the initial perceptions of children, their parents and school staff of using a biofeedback technique, HeartMath's emWave PC stress relief system, in four primary schools to support the development of emotional wellbeing. Interpretative Phenomenological Analysis was used to interpret information collected through 12 semi structured interviews, and the following themes were identified. The children's initial experiences were of a "calming-down game" to support them in managing anger through deep breathing and positive thought. School staff were divided in their perceptions between being "a little bit sceptical" and being 'blinded by science' by the information presented to them at their initial training. Consequently, some staff reported feeling insecure about using the technique with children. Issues of informed consent came to light through the parents' experiences and of 'intervention fatigue' - questioning whether this approach would help their children. Despite this, most parents reported noticing a positive change in their children coinciding with the use of the intervention. Themes addressing the experience of being, or supporting, an individual who needs to 'manage their feelings' were also explored. School staff discussed this from the perspective of social justice and inclusion for individuals, the school and their wider community. The children described their experiences of 'calming down' through the use of the HeartMath biofeedback technique and other anger management strategies. Parents spoke of parenting a child who has difficulties in 'managing' their feelings and the events which could trigger emotional arousal in their children. The results are" discussed in light of the promotion of emotional wellbeing in primary schools and my own emerging practice as an Educational Psychologist. As a relatively new area of Educational Psychology, a range of further research opportunities are outlined, arising from the use of biofeedback software in schools, as a targeted intervention or 'universal' strategy

A pilot study of secondary teachers' understanding of population dynamics

Population dynamics is a South African secondary school biology syllabus topic which deals specifically with ecology or concepts within the realm of ecology. It is currently taught in a way which largely emphasises the teaching and learning of facts and concepts, often out of any context to which students can relate. While it is important to convey scientific concepts, it is just as important to address social and political issues regarding overpopulation and the environment. This research involved the administration of a questionnaire to Std 10 biology teachers in the Department of Education and Training (DET), which sought to obtain information about various aspects of teachers' teaching of population dynamics. These included their feelings toward the teaching of the specific sections of the population dynamics syllabus, and their knowledge and views of environmental issues and human population expansion. The findings of the research suggest that population dynamics is an important topic for students to learn about. The traditional teacher-centred approach to teaching is used by the teachers in the research sample. The sections considered by the teachers to be most important for learning were also considered the most interesting and the easiest to teach. The majority of the teachers in the research sample recognised that human population growth is a global and local problem and that South Africa cannot sustain its present population growth. The teachers in the sample show a diversity of opinions about sustainable development, and have a limited understanding of the links between population, poverty and consumption. Important information gained from the research will be significant in the development of a teaching and learning module on population dynamics that reflects the aims and purpose of environmental education

Book Reviews

Book 1Book Title: Getting into Residency: A Guide for Medical StudentsBook Author: Kenneth V. IsersonPp. xviii + 431. $28,95. Tucson: Galen Press. 1993. ISBN 1-883620-10-4.Book 2Book Title: Molecular Biology of Digestive DiseaseBook Author: Ed. by Philip QuirkePp. vii + 116. £15. London: BMJ. 1994. ISBN 0-7279-0827-8.Book 3Book Title: Parkinson's DiseaseBook Author:  Ed. by Merton Sandler.Pp. ix + 65. £12/US$24. London: John Libbey, 1993. ISBN 0-86196-404-7.Book 4Book Title: Brain Work and Mental Activity: Quantitative Studies With Radioactive TracersBook Author: Ed. by N. A. Lassen, D. A. Ingvar, M. A. Raichle & L. FribergPP. 446. Illustrated. Copenhagen: Munksgaard. 1991. ISBN 87-16-10698-9.Book 5Book Title: Guidelines for Quality Assurance Programmes for Blood Transfusion ServicesBook Author: WHOPp. IV + 50. (Available in English; French and Spanish in preparation). SFr.12/US$10,80 (in developing countries SFr.8,40). Geneva: WHO. 1993. ISBN 92-4-154448-1. Order No. 1150392.Book 6Book Title: ABC of AlcoholBook Author: Ed. by Alex PatonPp. ix + 32. illustrated. £10. London: BMJ. 1994. ISBN 0-7279-D812-X.Book 7Book Title: Atlas of Surgical Exposures ofthe Lower ExtremityBook Author: A. Masquelet, C. McCullough, R Tubiana, I. Fyfe, L. Klenerman, E. LetoumelPp. 414. Illustrated. London: Manin Dunitz. 1993. ISBN 1-85317-D03-8

Books

Medical audit Audit in Action. Ed. by Richard Smith. Pp. xiv + 245. Illustrated. £10,95. London: British Medical Journal. 1992. Available from Libriger Book Distributors, Bloemfontein.Rheumatology Bailliere's Clinical Rheumatology: Giant Cell Arteritis and Polymyalgia RheuIDatica. Guest eds B. L. Hazleman and B.-A. Bengtsson. Pp. xi + 507. illustrated. £27,50. London: Bailliere Tindall. 1991.AIDS, drugs and sexual risk AIDS, Drugs and Sexual Risk. By N. McKeganey and M. Bamard. Johannesburg: Random Century. 1992.Radiation When is a Dose Not a Dose? By Victor P. Bond. Pp. 39. Illustrated. Bethesda: National Council on Radiation Protection and Measurements. 1992.Autoimmune disease Clinical and Molecular Aspects of Autoimmune Diseases. Vol. 8. Ed. by J. M. Cruse and R. E. Lewis. Pp. x + 258. Illustrated. SFr. 248. Basel: Karger. 1992.Biochemical toxicology Principles of Biochemical Toxicology. 2nd ed. By J. A. Timbrel!. Illustrated. Pp. 415. RI53,73. London: Taylor & Frands. 1991.Advances in pineal research Advances in Pineal Research. Vol. 6. Ed. by Andrew Foldes and R. J. Reiter. pp. viii + 286. illustrated. £32,50. London: John Libbey. 1991.Health care for the future The Future of Health Care. Pp. 83. Illustrated. London: British Medical Journal. 1992.STDs and AIDS School Health Education to Prevent AIDS and Sexually Transmitted Disease. Pp. 79. SFr. 18. Geneva: World Health Organisation. 1992

Clinical Problems in the Hospitalized Parkinson's Disease Patient: Systematic Review

The problems Parkinson's disease (PD) patients encounter when admitted to a hospital, are known to be numerous and serious. These problems have been inventoried through a systematic review of literature on reasons for emergency and hospital admissions in PD patients, problems encountered during hospitalization, and possible solutions for the encountered problems using the Pubmed database. PD patients are hospitalized in frequencies ranging from 7 to 28% per year. PD/parkinsonism patients are approximately one and a half times more frequently and generally 2 to 14 days longer hospitalized than non-PD patients. Acute events occurring during hospitalization were mainly urinary infection, confusion, and pressure ulcers. Medication errors were also frequent adverse events. During and after surgery PD patients had an increased incidence of infections, confusion, falls, and decubitus, and 31% of patients was dissatisfied in the way their PD was managed. There are only two studies on medication continuation during surgery and one analyzing the effect of an early postoperative neurologic consultation, and numerous case reports, and opinionated views and reviews including other substitutes for dopaminergic medication intraoperatively. In conclusion, most studies were retrospective on small numbers of patients. The major clinical problems are injuries, infections, poor control of PD, and complications of PD treatment. There are many (un-researched) proposals for improvement. A substantial number of PD patients' admissions might be prevented. There should be guidelines concerning the hospitalized PD patients, with accent on early neurological consultation and team work between different specialities, and incorporating nonoral dopaminergic replacement therapy when necessary. © 2011 Movement Disorder Societ

Exercise therapy for prevention of falls in people with Parkinson's disease: A protocol for a randomised controlled trial and economic evaluation

<p>Abstract</p> <p>Background</p> <p>People with Parkinson's disease are twice as likely to be recurrent fallers compared to other older people. As these falls have devastating consequences, there is an urgent need to identify and test innovative interventions with the potential to reduce falls in people with Parkinson's disease. The main objective of this randomised controlled trial is to determine whether fall rates can be reduced in people with Parkinson's disease using exercise targeting three potentially remediable risk factors for falls (reduced balance, reduced leg muscle strength and freezing of gait). In addition we will establish the cost effectiveness of the exercise program from the health provider's perspective.</p> <p>Methods/Design</p> <p>230 community-dwelling participants with idiopathic Parkinson's disease will be recruited. Eligible participants will also have a history of falls or be identified as being at risk of falls on assessment. Participants will be randomly allocated to a usual-care control group or an intervention group which will undertake weight-bearing balance and strengthening exercises and use cueing strategies to address freezing of gait. The intervention group will choose between the home-based or support group-based mode of the program. Participants in both groups will receive standardized falls prevention advice. The primary outcome measure will be fall rates. Participants will record falls and medical interventions in a diary for the duration of the 6-month intervention period. Secondary measures include the Parkinson's Disease Falls Risk Score, maximal leg muscle strength, standing balance, the Short Physical Performance Battery, freezing of gait, health and well being, habitual physical activity and positive and negative affect schedule.</p> <p>Discussion</p> <p>No adequately powered studies have investigated exercise interventions aimed at reducing falls in people with Parkinson's disease. This trial will determine the effectiveness of the exercise intervention in reducing falls and its cost effectiveness. This pragmatic program, if found to be effective, has the potential to be implemented within existing community services.</p> <p>Trial registration</p> <p>The protocol for this study is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12608000303347).</p

Peroxiredoxin 6 in human brain: molecular forms, cellular distribution and association with Alzheimer’s disease pathology

Peroxiredoxin 6 is an antioxidant enzyme and is the 1-cys member of the peroxiredoxin family. Using two-dimensional electrophoresis and Western blotting, we have shown for the first time that, in human control and brain tissue of patient’s with Alzheimer’s disease (AD), this enzyme exists as three major and five minor forms with pIs from 5.3 to 6.1. Using specific cellular markers, we have shown that peroxiredoxin 6 is present in astrocytes with very low levels in neurons, but not detectable in microglia or oligodendrocytes. In control brains, there was a very low level of peroxiredoxin 6 staining in astrocytes that was confined to a “halo” around the nucleus. In AD, there were marked increases in the number and staining intensity of peroxiredoxin 6 positive astrocytes in both gray and white matter in the midfrontal cortex, cingulate, hippocampus and amygdala. Confocal microscopy using antibodies to Aβ peptide, tau and peroxiredoxin 6 showed that peroxiredoxin 6 positive astrocytes are closely involved with diffuse plaques and to a lesser extent with neuritic plaques, suggesting that plaques are producing reactive oxygen species. There appeared to be little astrocytic response to tau containing neurons. Although peroxiredoxin 6 positive astrocytes were seen to make multiple contacts with tau positive neurons, there was no intraneuronal colocalization. In brain tissue of patients with AD, many blood vessels exhibited peroxiredoxin 6 staining that appeared to be due to the astrocytic foot processes. These results suggest that oxidative stress conditions exist in AD and that peroxiredoxin 6 is an important antioxidant enzyme in human brain defenses