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30 November 2021 | Story Leonie Bolleurs | Photo Supplied
Prof Johan Meyer, Senior Professor in the Department of Mathematics and Applied Mathematics, says he is looking forward to learning from others in the field during this collaboration.

What do trees, black holes, earthquakes, and time structures have in common? 

The answer to this question is that these, in one way or the other, form the focus of some of the abstracts delivered during the Annual Congress of the South African Mathematical Society. The society has as its main objective the advancement of mathematics in South Africa. 

The Department of Mathematics and Applied Mathematics at the University of the Free State (UFS), in conjunction with the South African Mathematical Society (SAMS 2021), is hosting the 64th Annual Congress of the society this week (29 November to 1 December 2021).

Prof Johan Meyer, Senior Professor in the department, says the congress, which is being conducted online, is focusing on all aspects of mathematics research, including history and teaching.

Learning from others in the field

The congress, which aims to share the latest research results in mathematics, will be attended by staff and students from universities across South Africa as well as abroad. “Anyone from the public is, of course, welcome to attend or even share their results if they are also involved in mathematics research,” adds Prof Meyer. 

He says that he is looking forward to learning from others in the field during this collaboration. 

The congress will include discussions on more than 120 abstracts, covering category theory, algebra, topology, logic; functional analysis and operator theory; finite groups and combinatorial structures; graph theory and combinatorics; lie symmetries and nonlinear differential equations; and applied and numerical mathematics.

Array of interesting topics presented

“It is important in many areas of science and engineering to predict and to simulate rare, random events, the occurrence of which may have negative or even catastrophic consequences. Examples include internet server overflows, mechanical breakdowns, floods, and financial crashes. Rare events can also have a positive effect, triggering for example chemical reactions or driving genetic evolution via random mutations.” Prof Hugo Touchette from Stellenbosch University will be shedding some light on this interesting topic in his presentation on Predicting and simulating rare events.

Prof Jeandrew Brink, Associate Professor in the Department of Mathematics and Applied Mathematics at the UFS, is presenting a plenary session on the topic Determining the geometry of strong field space-times in spite of tacitly assuming the answer during every measurement. In South Africa, state-of-the art pulsar timing data from the MeerKAT telescope will make a considerable contribution to conducting GR orbital tests. Prof Brink comments on how pulsar timing tests differ from tests using gravitational wave detectors, as well as what we can learn from the framework already employed to perform pulsar timing measurements.

News Archive

Sunflowers are satellite dishes for sunshine, or are they?
2016-07-20

Eighty-six percent of South Africa’s
sunflowers are produced in the
Free State and North West provinces.

Helen Mirren, the English actress, said “the sunflower is like a satellite dish for sunshine”. However, researchers at the University of the Free State (UFS) have found that too much of this sunshine could have a negative effect on the growth of sunflowers, which are a major source of oil in South Africa.

According to Dr Gert Ceronio from the Department of Soil, Crop, and Climate Sciences at the UFS, extremely high soil temperatures play a definite role in the sprouting of sunflower seedlings. Together with Lize Henning, professional officer in the department, and Dr André Nel from the Agricultural Research Council, he is doing research on biotic and abiotic factors that could have an impact on sunflowers.

Description: Sonneblom 2 Tags: Sonneblom 2

Various degrees of deformity (bad-left
to none-right) in seedlings of the same
cultivar at very high soil temperatures.
Photo: Dr Gert Ceronio

Impact of high temperatures on sunflower production

The Free State and North West provinces, which produce 86% of South Africa’s sunflowers, are afflicted especially by high summer temperatures that lead to extremely high soil temperatures.

Dr Ceronio says: “Although sunflower seeds are able to germinate at temperatures from as low as 4°C to as high as 41°C, soil temperatures of 35°C and higher could have a negative effect on the vegetative faculty of sunflower seedlings, and could have an adverse effect on the percentage of sunflowers that germinate. From the end of November until mid-January, this is a common phenomenon in the sandy soil of the Free State and North West provinces. Soil temperatures can easily exceed the critical temperature of 43°C, which can lead to poor germination and even the replanting of sunflowers.”

Since temperature have a huge impact not only on the germination of sunflower seeds, but also on the vegetative faculty and sprouting of sunflower seedlings, Dr Ceronio suggests that sunflowers should be planted in soil with soil temperatures of 22 to 30°C. Planting is usually done in October and early November. Unfortunately, this is not always possible, as soil moisture is not optimal for growth. Farmers are then compelled to plant sunflowers later.

Impact of herbicides on sunflower growth

“High soil temperatures, combined with the herbicide sensitivity of some cultivars, could lead to the poor development of seedlings," says Dr Ceronio.

The use of herbicides, such as ALACHLOR, for the control of weeds in sunflowers is common practice in sunflower production. It has already been determined that ALACHLOR could still have a damaging effect on the seedlings of some cultivars during germination and sprouting, even at recommended application dosages.

“The purpose of the continued research is to establish the sensitivity of sunflower cultivars to ALACHLOR when exposed to high soil temperatures,” says Dr Ceronio.

 

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