Human African Trypanosomiasis (HAT) and Nagana in cattle, commonly called sleeping sickness, is caused by trypanosome protozoa transmitted by bites of infected tsetse flies. We present a deterministic model for the transmission of HAT caused by Trypanosoma brucei gambiense between human hosts, cattle hosts and tsetse flies. The model takes into account the growth of the tsetse fly, from its larval stage to the adult stage. Disease in the tsetse fly population is modeled by three compartments, and both the human and cattle populations are modeled by four compartments incorporating the two stages of HAT. We provide a rigorous derivation of the basic reproduction number R0. For R0 < 1, the disease free equilibrium is globally asymptotically stable, thus HAT dies out; whereas (assuming no return to susceptibility) for R0 >1, HAT persists. Elasticity indices for R0 with respect to different parameters are calculated with baseline parameter values appropriate for HAT in West Africa; indicating parameters that are important for control strategies to bring R0 below 1. Numerical simulations with R0 > 1 show values for the infected populations at the endemic equilibrium, and indicate that with certain parameter values, HAT could not persist in the human population in the absence of cattle.
This research involves eight students at the University of Pretoria who identify with the Bachelor of Science (BSc) and the Bachelor of Commerce (BCom) Extended Curriculum Programmes (ECPs). The study reports on the use of Appreciative Inquiry (AI) to determine how these students describe the best aspects of the programmes and the attributes that they developed in order to succeed. The aim was to extrapolate the findings to develop an improvement plan informed by students' perspectives. The narratives from semi-structured interviews conducted during the Discovery and Dream stages of the modified Appreciative Inquiry 4-D process are reported. Six views emerged: sense of family and belonging; peer mentoring and support networks; coping with failure and developing self-efficacy; the underdog phenomenon, self-motivation and support for mainstream students; the student advising model; and extended curriculum programmes as a first option. In the Design phase, these views will be incorporated to formulate an improvement plan for the programmes. Ogude, Mwambakana, Meyer and Mthethwa Improvement of extended curricular programmes 220 BACKGROUND Access Programmes are university programmes that are designed to accommodate students from disadvantaged academic backgrounds who are not adequately prepared for university (Rollnick 2010). Extended Curriculum Programmes (ECPs) are a type of the Access Programmes in which students are transitioned into tertiary education by incorporating modules that are in line with the mainstream academic programmes. Extended Curriculum Programmes are thus credit bearing, and students enter the mainstream after the extended phase of their degree. Other types of Access Programmes include the Foundation Programmes and the Augmented Programmes. Regarding the Foundation Programmes, students complete a year of non-credit bearing modules that are separate from the mainstream academic programmes. Augmented Programmes are a complete modification of the entire academic programme, which enables students to complete a modified degree programme over an extended period (Rollnick 2010). The Mamelodi Campus of the University of Pretoria has been offering ECPs since 2008. Currently, three BSc programmes, namely Mathematical Sciences, Physical Sciences and Biological and Agricultural Sciences are offered by the Faculty of Natural and Agricultural Sciences. A BCom Extended Programme is offered by the Faculty of Economic and Management Sciences. The admission requirements are lower for the programmes than for the mainstream programmes since the majority of the students admitted on the campus do not meet the mainstream admission requirements. At the University of Pretoria, the first phase of the extended programmes involves a time period of 18 months or three semesters, two of which are hosted at the Mamelodi Campus. These 18 months replace the first semester, and the students eventually complete the 3-year BSc and BCom degrees in four years.The aim of the extended programmes is to enhance students' basic knowledge a...
: We provide a mathematical analysis of a break-up model with the newly developed Caputo-Fabrizio fractional order derivative with no singular kernel, modeling rock fracture in the ecosystem. Recall that rock fractures play an important role in ecological and geological events, such as groundwater contamination, earthquakes and volcanic eruptions. Hence, in the theory of rock division, especially in eco-geology, open problems like phenomenon of shattering, which remains partially unexplained by classical models of clusters' fragmentation, is believed to be associated with an infinite cascade of breakup events creating a 'dust' of stone particles of zero size which, however, carry non-zero mass. In the analysis, we consider the case where the break-up rate depends of the size of the rock breaking up. Both exact solutions and numerical simulations are provided. They clearly prove that, even with this latest derivative with fractional order and no singular kernel, the system describing crushing and grinding of rocks contains (partially) duplicated fractional poles. According to previous investigations, this is an expected result that provides the new Caputo-Fabrizio derivative with a precious and promising recognition.
This study investigated the prevalence of Escherichia coli O157:H7 in the stool of confirmed and non-confirmed diarrhoeic HIV/AIDS patients. Escherichia coli O157:H7 was isolated by culture-based and immunomagnetic separation from three hundred and sixty stool swabs. Identification was by conventional IMViC, 20E API and molecular techniques. Confirmed and non-confirmed diarrhoeic HIV/AIDS patients had 56.5% (74/131) and 43.5% (57/131) respectively of E. coli O157:H7. Molecular results indicated that the prevalence of E. coli O157:H7 was 12.16% (9/74) and 8.77% (5/57) from stool swabs of confirmed and non-confirmed diarrhoeic HIV/AIDS patients. Antimicrobial resistance was higher for E. coli O157:H7 isolates from stools of confirmed HIV/AIDS than it was for non-confirmed HIV/AIDS patients. Escherichia coli O157:H7 might be a silent cause of diarrhoea in HIV/AIDS patients. It is recommended that HIV/AIDS patients with diarrhoea should be screened for E. coli O157:H7 and surveillance programmes for these bacteria should be established in both urban and rural areas of South Africa.
Immunosuppressed persons such as HIV/AIDS patients are at risk of acquiring diarrhoeal infections from water-borne E. coli O157:H7. In the present study, we investigated the prevalence of E. coli O157:H7 in drinking water collected from selected distribution systems within the Amathole District of the Eastern Cape and its predicted impact on diarrhoeic conditions of HIV/AIDS persons living in this area. One hundred and eighty water samples and 360 stool swabs from confirmed and nonconfirmed HIV/AIDS diarrhoeic patients were analysed. Escherichia coli O157:H7 were isolated using enrichment culture and confirmed using molecular techniques.Of the 180 drinking water samples, 46 (25.56%) were positive for E. coli O157. The prevalence of E. coli O157 in the stools was at 36.39% (131/360) of which 56.5% (74/131) and 43.5% (57/131) were from stools of confirmed and non-confirmed HIV/AIDS patients, respectively. Molecular analysis of 27, 25 and 29 representative presumptive E. coli O157 from water and stools of confirmed and non-confirmed HIV/AIDS patients, respectively, revealed that 14.81%, 36% and 17.24% of the isolates were E. coli O157:H7. The findings predicted a possible link between E. coli O157:H7 isolated from drinking water and diarrhoeic conditions of both confirmed and non-confirmed HIV/AIDS patients visiting Frere Hospital for treatment.
South Africa finds itself with skills shortages in scientifically oriented professions. A major contributor to this has been students' failure in mathematics. This study set out to identify students who self-reported mathematics anxiety and determine if this was a factor in their studies. Participants were 204 mathematics first-year students registered for degrees in Engineering, Information Technology, and Natural Science. Included in this group were Foundation Year students. Results indicated that the majority of students admitted to higher levels of anxiety. With respect to the different degree programmes, chemistry students reported higher anxiety. Specifically, a negative association was established between performance and mathematics evaluation anxiety. It is concluded that lecturers through investigations such as this can identify and isolate highly anxious mathematics students. Such students may receive remedial psychological help or at least, lecturers may revise their presentation methods to suit these particular students. The study also concluded that there are underlying problems within the teaching and learning of mathematics among the study sample. As is typical of this type of investigation, a number of questions remain unanswered such as what the sources of students' mathematics anxiety are and how these relate to the variables investigated here. A follow-up study will focus more closely on these issues.
The purpose of mathematics competitions, and in our case the South African Mathematics Olympiad (SAMO), is to promote problem solving skills and strategies, to generate interest and enthusiasm for mathematics and to identify the most talented mathematical minds. SAMO is organised in two divisions -a junior and a senior division -over three rounds. We analysed the results of the junior second round over seven years [2006][2007][2008][2009][2010][2011][2012]. Based on the literature a mathematical content framework was developed, dividing the mathematical content into seven broad content areas. In this paper we investigate the face validity, diagnostic attributes and predictive criterion validity of mathematics olympiad question papers over the period by focussing on the frequency of content area occurrence in the different items. We also look at performance of contestants in the different content areas as a broad diagnosis. Lastly we investigate the item performance, comparing the expected performance by the problem committee of experts setting the question papers and the actual performance of contestants. Topics such as numbers, algebra, patterns and functions, measurement, applications, modelling and logic were used abundantly whereas (quite surprisingly) there were few items on graphs, decimal fractions, spatial logic and vertices and edges of polygons, indicating that the face validity can be improved. Contestants performed best in items on algebra and weakest in items on statistics. The ability of the problem committee to anticipate student item performance varied considerably and was significantly worse in 2012 than in 2006, indicating better predictive criterion validity in 2006.
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