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05 September 2022 | Story Andrè Damons | Photo Andrè Damons
Prof Abdon Atangana
Prof Abdon Atangana, Professor of Applied Mathematics in the Institute for Groundwater Studies (IGS) and a highly cited mathematician for the years 2019-2021, says existing mathematical models are used to first fit collected data and then predict future events. It is for this reason he introduced a new concept that can be used to test whether the spread will have one or several waves.

With a new outbreak of the Ebola Virus Disease (EVD) reported this year in Democratic Republic of the Congo (DRC) – the 14th EVD outbreak in the country – researchers at the University of the Free State (UFS) introduced a new concept that can be used to test whether the spread will have one or several waves. They believe the focus should be to identify the source or the hosts of this virus for it to be a complete eradication. 

According to the Centers for Disease Control and Prevention (CDC), the Ministry of Health in the Democratic Republic of the Congo (DRC) declared an outbreak of Ebola in Mbandaka health zone, Equateur Province on April 23, 2022. EVD, formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness affecting humans and other primates. The virus is transmitted to people from wild animals (such as fruit bats, porcupines and non-human primates) and then spreads in the human population through direct contact with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids, according to the World Health Organisation (WHO).
 
Prof Abdon Atangana, Professor of Applied Mathematics in the Institute for Groundwater Studies (IGS), says existing mathematical models are used to first fit collected data and then predict future events. Predictions help lawmakers to take decisions that will help protect their citizens and their environments. The outbreaks of COVID-19 and other infectious diseases have exposed the weakness of these models as they failed to predict the number of waves and in several instances; they failed to predict accurately day-to-day new infections, daily deaths and recoveries.

Solving the challenges of the current models

In the case of COVID-19 in South Africa, it is predicted that the country had far more infections than what was recorded, which is due to challenges faced by the medical facilities, poverty, inequality, and other factors. With Ebola in the DRC, data recorded are not far from reality due to the nature of the virus and its symptoms. However, the predictions show although some measures have been put in place in DRC and other places where the Ebola virus spread, they will still face some challenges in the future, as the virus will continue to spread but may have less impact. 

“To solve the challenges with the current models, we suggested a new methodology. We suggested that each class should be divided into two subclasses (Detected and undetected) and we also suggested that rates of infection, recovery, death and vaccination classes should be a function of time not constant as suggested previously. These rates are obtained from what we called daily indicator functions. For example, an infection rate should be obtained from recorded data with the addition of an uncertain function that represents non-recorded data (Here more work is still to be done to get a better approximation).

“I introduced a new concept called strength number that can be used to test whether the spread will have one or several waves. The strength number is an accelerative force that helps to provide speed changes, thus if this number is less than zero we have deceleration, meaning there will be a decline in the number of infections. If the number is positive, we have acceleration, meaning we will have an increase in numbers. If the number is zero, the current situation will remain the same,” according to Prof Atangana. 

To provide better prediction, he continues, reliable data are first fitted with the suggested mathematical model. This helps them to know if their mathematical model is replicating the dynamic process of the spread. The next step is to predict future events, to do this, we create three sub-daily indicator functions (minimum, actual, and maximum). These will lead to three systems, the first system represents the worst-case scenario, the second is the actual scenario, and the last is a best-case scenario.

Virus will continue to spread but with less impact

Using this method, Prof Atangana, a highly cited mathematician for the years 2019-2021, says he and Dr Seda Igret Araz, postdoctoral student, were able to predict that, although some measures have been put in place in DRC and other places where the Ebola virus spreads, they will still face some challenges in the future as the virus will continue to spread but may have less impact. 

To properly achieve the conversion from observed facts into mathematical formulations and to address these limitations, he had to ask fundamental questions such as what is the rate of infection, what is the strength of the infection, what are the crossover patterns presented by the spread, how can day-to-day new infected numbers be predicted and what differential operator should be used to model a dynamic process followed by the spread?

This approach was tested for several infectious diseases where we present the case of Ebola in Congo and Covid-19 in South Africa.  

News Archive

Code-switching, tokenism and consumerism in print advertising
2014-10-27

Code-switching, linguistic tokenism and modern consumerism in contemporary South African print advertising. This is the current research focus of two lecturers from the Faculty of the Humanities at the UFS, Prof Angelique van Niekerk and Dr Thinus Conradie.

The act of switching between two or more languages is replete with socio-cultural meaning, and can be deployed to advance numerous communicative strategies, including attempts at signalling cultural familiarity and group affiliation (Chung 2006).

For advertising purposes, Fairclough’s (1989) seminal work on the ideological functions of language remark on the usefulness of code-switching as a means of fostering an advertiser-audience relationship that is conducive to persuasion. In advertising, code-switching is a valuable means with which a brand may be invested with a range of positive associations. In English-dominated media, these associations derive from pre-existing connotations that target audiences already hold for a particular (non-English) language. Where exclusivity and taste, for example, are associated with a particular European language (such as French), advertising may use this languages to invest the advertised brand with a sense of exclusivity and taste.

In addition, empirical experiments with sample audiences (in the field of consumer research) suggest that switching from English to the first language of the target audience, is liable to yield positive results in terms of purchase intentions (Bishop and Peterson 2011). This effect is enhanced under the influence of modern consumerism, in which consumption is linked to the performance of identity and ‘[b]rands are more than just products; they are statements of affiliation and belonging’ (Ngwenya 2011, 2; cf. Nuttall 2004; Jones 2013).

In South African print magazines, where the hegemony of English remains largely uncontested, incorporating components of indigenous languages and Afrikaans may similarly be exploited for commercial ends. Our analysis suggests that the most prevalent form of code-switching from English to indigenous South African languages represents what we have coded as linguistic tokenism. That is, in comparison with the more expansive use of both Afrikaans and foreign languages (such as French), code-switching is used in a more limited manner, and mainly to presuppose community and solidarity with first-language speakers of indigenous languages. In cases of English-to-Afrikaans code-switching, our findings echo the trends observed for languages such as French and German. That is, the language is exploited for pre-existing associations. However, in contrast with French (often associated with prestige) and German (often associated with technical precision), Afrikaans is used to invoke cultural stereotypes, notably a self-satirical celebration of Afrikaner backwardness and/or lack of refinement that is often interpolated with hyper-masculinity.

References


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