Implementation of a Gauss convoluted Pandel PDF for track reconstruction in Neutrino Telescopes

A probability distribution function is presented which provides a realistic description of the detection of scattered photons. The resulting probabilities can be described analytically by means of a superposition of several special functions. These exact expressions can be evaluated numerically only for small distances and limited time residuals, due to computer accuracy limitations. In this report we provide approximations for the exact expressions in different regions of the distance-time residual space, defined by the detector geometry and the space-time scale of an event. These approximations can be evaluated numerically with a relative error with respect to the exact expression at the boundaries of less than 0.001.Comment: 9 pages, 4 figures Revision 1 : extended content 12 pages, 4 figures Accepted for publication in Astroparticle Physic

Usability guidelines informing knowledge visualisation in demonstrating learners' knowledge acquisition

There is growing evidence that knowledge co-creation and interactivity during learning interventions aid knowledge acquisition and knowledge transfer. However, learners have mostly been passive consumers and not co-creators of the knowledge visualisation aids created by teachers and instructional designers. As such, knowledge visualisation has been underutilised for allowing learners to construct, demonstrate and share what they have learned. The dearth of appropriate guidelines for the use of knowledge visualisation for teaching and learning is an obstacle to using knowledge visualisation in teaching and learning. This provides a rationale for this study, which aims to investigate usability-based knowledge visualisation guidelines for teaching and learning. The application context is that of Science teaching for high school learners in the Gauteng province of South Africa. Following a design-based research methodology, an artefact of usability-based knowledge visualisation guidelines was created. The artefact was evaluated by testing learners’ conformity to the visualisation guidelines. Qualitative and quantitative data was captured using questionnaires, interviews and observations. The findings indicate that the guidelines considered in this study had various degrees of impact on the visualisations produced by learners. While some made noticeable impact, for others it could be considered negligible. Within the context of high school learning, these results justify the prioritisation of usability-based knowledge visualisation guidelines. Integrating Human Computer Interaction usability principles and knowledge visualisation guidelines to create usability-based knowledge visualisation guidelines provide a novel theoretical contribution upon which scientific knowledge visualisation can be expanded.School of ComputingM. Sc. (Computing

A comparative study of the phosphate levels in some surface and ground water bodiesof Swaziland

The levels of total phosphate in selected surface water and groundwater bodies from Manzini and Lubombo regions of Swaziland were determined using UV spectroscopic method. Samples were collected from three rivers (upstream and downstream of each), three industrial effluents, one reservoir, one pond, one tap water and fifteen boreholes. Mean phosphate levels in the tap water and reservoir varied between 0.08-0.09 mg/L while for the river samples, the range was 0.11-0.37 and for the industrial discharge, it was 0.11-1.60 mg/L PO4–P. For the ground water systems it ranged between 0.10-0.49 mg/L PO4–P. The mean phosphate levels in all the analyzed surface and groundwater samples were below the recommended maximum contaminant level (MCL) by SWSC (Swaziland Water Service Corporation) – i.e. 1.0 mg/L for drinking water; 2.0 mg/L for rivers and industrial effluents, and the South African criterion of 1.0 mg/L PO4–P, for sewage effluents being discharged into receiving waters. However, pooled mean values for all the sites were higher than the USEPA criterion of 0.03 mg/L maximum for uncontaminated lakes. Dominant factors considered to have influenced the levels of phosphates in both the surface and groundwater samples analyzed include industrial activities (where present), agricultural activities (including livestock), population density, location (urban, suburban or rural), soil/rock type in the vicinity of the sampling point, climate and rainfall pattern of the area or region concerned. KEY WORDS:  Surface water, Groundwater, Limiting nutrient, Eutrophication, Algal bloom, Anthropogenic phosphate sources  Bull. Chem. Soc. Ethiop. 2008, 22(2), 197-206

Giant inguino scrotal hernia: a case report

A journal article on scrotal hernia diseases in developing countries.Giant inguino — scrotal hernia is largely a problem of developing countries. A case of an unusually giant inguino-scrotal hernia is reported highlighting the problems encountered in management. Orchidectomy, bowel resection and relaxing epigastric incision were successfully employed in repairing the hernia. Hernias may not be difficult to manage if they ar not neglected. Efforts of health education need intensifying in this direction. We propose thorough peri-operative pulmonary exercises to cut down the post-operative pulmonary morbidity

Characterization and use of pollen as a biorenewable filler for polymer composites

Fillers are often incorporated in polymer matrices in order to improve cost, mechanical, thermal, and transport properties. This work explores the hypothesis that pollen, a natural particle, has the potential to be an effective biorenewable reinforcing filler due to its unique surface architectures, high strength, chemical stability, and low density. Pollens from sources such as ragweed plants are ubiquitous natural materials that are based on sustainable, non-food resources. Pollen is a remarkable example of evolutionary-optimized microscale particle with structures and/or chemistries tailored for effective adhesion to a variety of surfaces and protection of genetic material under different dynamic and environmental conditions. The pollen shell is perhaps the most chemically resistant naturally occurring material. As many pollens achieve pollination simply by being carried by wind, they are very light-weight. These properties make pollen an attractive option as a natural filler for polymers. This research aims to characterize pollen interfacial properties and utilize pollen as an effective reinforcing filler in polymer materials. In this work, interfacial properties are characterized using Fourier transform infrared spectroscopy (FTIR), the BET method, and inverse liquid chromatography (ILC). These techniques were useful in determining the effect of surface treatments and further chemical modifications on pollen interfacial properties. Characterizing these properties allowed for improved understanding and utilization of pollen as a filler by revealing the enhanced surface interactions and surface properties of acid-base treated pollens when compared to as received untreated pollens. Epoxy and polyvinyl acetate (PVAc) matrices were used to demonstrate the effectiveness of pollen as a filler, as a function of pollen loading and surface treatments/chemical modifications. Scanning electron microscopy (SEM) was used to determine interfacial morphology, a high throughput mechanical characterization device (HTMECH) was used to determine mechanical properties, and differential scanning calorimetry (DSC) was used to determine glass transition behavior. In epoxy, pollen was an effective load bearing filler only after modifying its surface with acid-base hydrolysis. In PVAc, pollen was an effective load bearing filler only after an additional functionalization with a silane coupling agent. Finally, the species of pollen incorporated in PVAc matrices was varied in order determine the effect of the size of surface nano- and micro- structures on wetting, adhesion, and composite properties. Composites containing pollen displayed enhanced wetting and interfacial adhesion when compared to composites with smooth silica particles. Additionally, it was observed that pollen with smaller surface structures were wetted more effectively by the polymer matrix than pollen with larger structures. However, mechanical properties did not suggest significant changes in interfacial adherence with varied pollen microstructure size. The results of this work highlight the feasibility and potential of utilizing pollen as a natural filler for creating high strength, light-weight polymer composites with sustainable filler.Ph.D

Analysis of Volatility transmission across South African Financial Markets

This paper analyses volatility transmission across four South African financial markets, using daily data for the period 2000-2009. These are the stock, bond, money and foreign exchange markets. The paper applies the TARCH procedure to the returns from the South African financial markets in order to estimate the cross-market volatility transmission. Results show that volatility transmission exists in South African financial markets on a weak form, with each market explaining its own volatility. The paper found transmission between stocks market and foreign exchange, and between foreign exchange and bond markets

A WEIGHT CHECKER BASED ON DIGITAL TECHNIQUE

Recent advances in digital computer and digital communications systems have led to a corresponding growing interest in digital weight techniques because of engineering advances offered by digital systems over its analogue counterpart. In this work, a digital weight checker liquid crystal display has been designed. The weight checker uses linear voltage differential transformer (LVDT) transducer in which position of displacement of spiral is proportional to the output voltage of transducer. Its accuracy and provision of constant impedance with infinite resolution makes it suitable for most applications. The system has its range from 0 to 20v corresponding to 0 to 20kg

EFFECTS OF ORGANIC FERTILISERS ON GROWTH, YIELD AND NUTRITIONAL CONTENT OF SNOW PEAS (Pisum sativum var. saccharatum)

Snow peas (Pisum sativum var. saccharatum) are one of the widely used baby vegetable in Swaziland; however, there is a dearth of information pertaining to its organic production. A field study laid out in Factorial Randomised Complete Block Design was conducted at the Horticulture Farm, Luyengo Campus, of the University of Swaziland. Organic fertilisers used were kraal manure, broiler manure, and Igrow, applied at 20, 40, and 60 (t/ha). Inorganic fertilisers 2:3:2 (22) + 0.5% zinc and limestone ammonium nitrate (28%) were applied at 100 kg/ha and 80 kg/ha respectively. A trend of superiority of the different levels of organic manure application was observed as snow peas provided with 40 t/ha and 60 t/ha exhibited higher values in vegetative and reproductive growth, marketable yield and protein content especially on broiler and kraal manure application. The use of broiler manure at 40 t/ha and 60 t/ha in the production of vegetables like snow peas should be encouraged, because their application resulted in increased growth and yield compared to synthetic fertilisers

Detecting a stochastic gravitational wave background with the Laser Interferometer Space Antenna

The random superposition of many weak sources will produce a stochastic background of gravitational waves that may dominate the response of the LISA (Laser Interferometer Space Antenna) gravitational wave observatory. Unless something can be done to distinguish between a stochastic background and detector noise, the two will combine to form an effective noise floor for the detector. Two methods have been proposed to solve this problem. The first is to cross-correlate the output of two independent interferometers. The second is an ingenious scheme for monitoring the instrument noise by operating LISA as a Sagnac interferometer. Here we derive the optimal orbital alignment for cross-correlating a pair of LISA detectors, and provide the first analytic derivation of the Sagnac sensitivity curve.Comment: 9 pages, 11 figures. Significant changes to the noise estimate