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.

No abstract

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.