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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

Prof Hendrik Swart richly contributes to research of phosphors
2014-12-02

Prof Hendrik Swart
Photo: Merwelene van der Merwe

Since his appointment as the South African Research Chairs Initiative (SARChI) Chair, there has been a sharp increase in the number of papers and publications by Prof Hendrik Swart, Senior Professor in the Department of Physics at the University of the Free State (UFS). From January this year, he has already published 78 articles. Some of the journals that has published his work, includes:

• Nanotechnology (impact of 3.67)
• Dalton Transactions (impact of 4.097)
• Sensors and Actuators B: Chemical (impact 3.84)

“My biggest success, however, is the powerful group of researchers we have built over the years. Staff, postdocs and students – without them it would have been impossible. I am therefore much indebted to my groups on both the Bloemfontein and Qwaqwa Campuses.

“The good apparatus we acquired via a sponsorship from the National Research Foundation and Sasol is also one of the main reasons for this. The financial support I get from the university’s research office is of course also a contributing factor,” he says.

For the past 20 years, Prof Swart has been conducting research on any substance that glows. “I only adjust the focus to fit in with current trends,” he says.

Prof Swart believes that his research will make a contribution to the fundamental knowledge about phosphors, as well as to the training of good students for the academic and industrial world on the outside. For the man on the street, his research translates into better, brighter lights that use less energy.

His more recent research focuses on the development of nano-phosphors for light-emitting diodes (LEDS) and organic light-emitting diodes (OLED).

Prof Swart has presented papers on his research not only nationally, but all over the world – including countries in Europe and the East. Some of the most recent papers presented by him and his colleagues/postgraduate students include:

• Applications of AES, XPS and TOF SIMS to phosphor materials at die 15th European Conference on Applications of Surface and Interface Analysis 2013 in Forte Village Resort, Sardinia, Italy.
• Luminescent properties of phosphor nano thin films at the first International Symposium on Nanoparticles/Nanomaterials and Applications in Caparica (Lisbon, Portugal), where he was an invited speaker.
• Role of surface and deep-level defects on the emission of nano metal oxides at the 2014 NanoAfrica international conference, Vanderbijlpark, South Africa, where he delivered the keynote address.
• PHI systems and their modifications at KOVSIES at the PHI European User Meeting in Ismaning (Munich), Germany, where he was invited to speak.

Prof Swart also delivered the keynote address at the SETCOR International Conference on Smart Materials and Surfaces in Bangkok, Thailand. His lecture was titled, ‘Role of surface and deep-level defects on the emission and degradation of phosphor materials’.

 

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