19 Works

Numerical Analysis of the Transient and Non-Isothermal Channel Flow of a Third-Grade Fluid with Convective Cooling

Tiri CHINYOKA & Oluwole Daniel MAKINDE
We investigate the unsteady, non-isothermal, pressure driven channel flow of a third grade liquid subject to exothermic reactions. We assume temperature dependent fluid viscosity and also that the flow is subjected to convective cooling at the channel walls. The exothermic reactions are modelled via Arrhenius kinetics and the convective heat exchange with the ambient at the channel walls follows Newton’s law of cooling. The time-dependent, coupled, and nonlinear partial differential equations governing the flow and...

Impacts of invasive Australian acacias on soil bacterial community composition, microbial enzymatic activities, and nutrient availability in fynbos soils

Jan-Hendrik Keet
Invasive nitrogen-fixing plants often impact the soils they invade, notably through changes in soil chemistry and microbial community composition, which in turn could lead to alterations in soil functionality. We aimed to determine the impacts that invasive Australian Acacia trees have on soil chemistry and function (carbon, nitrogen, and phosphorus cycling) in South Africa’s Core Cape Subregion, and whether any differences in soil function are linked to differences in soil chemical properties and bacterial community...

The effect of storage conditions on microbial communities in stool

Kristien Nel Van Zyl
Microbiome research has experienced a surge of interest in recent years due to the advances and reduced cost of next-generation sequencing technology. The production of high quality and comparable data is dependent on proper sample collection and storage and should be standardized as far as possible. However, this becomes challenging when samples are collected in the field, especially in resource-limited settings. We investigated the impact of different stool storage methods common to the TB-CHAMP clinical...

Character displacement drives floral variation in Pelargonium (Geraniaceae) communities

Ethan Newman & Bruce Anderson
Interactions between plant community members are an underexplored driver of angiosperm floral variation. We investigate character displacement as a potential contributor to floral variation in Pelargonium communities. Pelargoniums all place pollen on the ventral sides of their pollinators, potentially leading to interspecific pollen transfer (IPT) in sympatry. We show that the positions of pollen placement and receipt are determined by anther and style exsertion lengths. Using field experiments, we demonstrate that heterospecific species experience high...

Data for: Calibration of individual-based models to epidemiological data: a systematic review

C. Marijn Hazelbag, Jonathan Dushoff, Emanuel M. Dominic, Zinhle E. Mthombothi & Wim Delva
Calibrating or fitting an individual-based model (IBM) to data is a crucial step in model development. We performed a systematic review to provide an overview of calibration methods used in IBMs modelling infectious disease spread. We included articles if models stored individual-specific information and calibration involved running the model and comparing model output to population-level targets expressed as summary statistics. The dataset contains information for each of the included articles on model calibration methods, including;...

Cattaneo-Christov Heat Flux on an MHD 3D Free Convection Casson Fluid Flow Over a Stretching Sheet

D. Gowri SHANKAR, C.S.K. RAJU, M.S. Jagadeesh KUMAR & Oluwole Daniel MAKINDE
In this investigation, we analyze the magnetohydrodynamic (MHD) three-dimensional (3D) flow of Casson fluid over a stretching sheet using non-Darcy porous medium with heat source/sink. We also consider the Cattaneo-Christov heat flux and Joule effect. The governing partial differential equations (PDEs) are transformed into ordinary differential equations (ODEs) using suitable transformations and solved by using the shooting technique. The effects of the non-dimensional governing parameters on velocity and temperature profiles are discussed with the graphs....

Fine-scale invasion genetics of the quarantine pest, Anoplophora glabripennis, reconstructed in single outbreaks

Tetyana Tsykun, Marion Javal, Doris Hölling, Géraldine Roux & Simone Prospero
The xylophagous cerambycid Anoplophora glabripennis, the Asian long-horned beetle (ALB), is highly polyphagous and can colonize a wide range of broadleaved host trees causing significant economic damage. For this reason, it is considered a quarantine pest in Europe and North America. Although the global spread of ALB has been depicted recently, no comprehensive studies exist on the genetic pattern of populations’ establishment and dynamics at fine-scale (i.e. within invasive outbreaks), before eradication measures are applied....

Summary of the microsatellite genotyping analysis of 280 C. gariepinus samples originating from eight locations in the Congo basin using five microsatellite markers

Maarten Van Steenberge, Maarten Vanhove, Auguste Chocha Manda, Maarten Larmuseau, Belinda Swart, Faustin Khang'Mate, Allan Arndt, Bart Hellemans, Jeroen Van Houdt, Jean-Claude Micha, Stephan Koblmüller, Rouvay Roodt-Wilding & Filip Volckaert
Aim The formation history of Africa’s current river basins remains largely unknown. In order to date changes in landscape and climate, we studied the biogeography of the African freshwater fish with the largest natural distribution. We also validated biogeographic units. Location Continental Africa. Taxon Clarias gariepinus sl. Methods We investigated mitochondrial cytb sequences of 443 individuals from 97 localities, using a haplotype network and a genetic landscape analysis. We inferred a dated phylogeny using maximum...

How competitive intransitivity and niche overlap affect spatial coexistence

Yinghui Yang & Cang Hui
Competitive intransitivity is mostly considered outside the main body of coexistence theories that rely primarily on the role of niche overlap and differentiation. How the interplay of competitive intransitivity and niche overlap jointly affects species coexistence has received little attention. Here, we consider a rock-paper-scissors competition system where interactions between species can represent the full spectra of transitive-intransitive continuum and niche overlap/differentiation under different levels of competition asymmetry. By comparing results from pair approximation that...

Supporting fisheries management with genomic tools: a case study of kingklip (Genypterus capensis) off southern Africa

Melissa Jane Schulze, Sophie Von Der Heyden & Romina Henriques
Kingklip, Genypterus capensis, is a valuable fish resource in southern African waters, with a wide geographic distribution spanning South Africa and Namibia. Previous studies have provided evidence for multiple stocks in South Africa, but the extent of stock structuring across the Southern African region remains unclear. In this study, we genotyped over 40 000 SNPs to characterise the spatial distribution of genomic variation for G. capensis throughout its core distribution. Results suggest that fish sampled...

Data from: An operational definition of the biome for global change research

Timo Conradi, Jasper A. Slingsby, Guy F. Midgley, Henning Nottebrock, Andreas H. Schweiger & Steven I. Higgins
Biomes are constructs for organising knowledge on the structure and functioning of the world's ecosystems, and serve as useful units for monitoring how the biosphere responds to anthropogenic drivers, including climate change. The current practice of delimiting biomes relies on expert knowledge. Recent studies have questioned the value of such biome maps for comparative ecology and global-change research, partly due to their subjective origin. Here we propose a flexible method for developing biome maps objectively....

Microsatellite matrix of Poa annua

Mario Mairal, Johannes Le Roux, Steven Chown, Justine Shaw, Desalegn Chala, John Chau, Bettine Van Vuuren, Cang Hui & Zuzana Münzbergová
Comparative studies of invasive species in human-inhabited versus truly uninhabited habitats, particularly on their genetic structure, remain scarce. Sub-Antarctic islands provide an ideal system to study invasions in such contrasting environments as they represent semi-pristine conditions in highly remote areas that are accessible only through a small number of introduction routes. Here we studied the invasion genetics of annual bluegrass Poa annua on the Prince Edward Islands (PEI) that include the inhabited Marion Island and...

Migration Study in the Western Cape 2001


Entropy Analysis of a Variable Viscosity MHD Couette Flow Between Two Concentric Pipes with Convective Cooling

Oluwole Daniel MAKINDE & Adetayo Samuel EEGUNJOBI
This paper addresses the combined effects of the magnetic field, thermal buoyancy force, viscous dissipation, Joule heating and temperature-dependent viscosity on the Couette flow of an incompressible conducting fluid between two concentric vertical pipes. It is assumed that convective cooling occurs at the surface of the outer moving pipe while the surface of the inner fixed pipe is maintained at a constant temperature. The nonlinear equations for momentum and energy are obtained and solved numerically...

Primary detection records for aquatic nonindigenous species in global estuarine and marine ecosystems and the Great Lakes

Sarah Bailey, Lyndsay Brown, Marnie Campbell, João Canning-Clode, James Carlton, Nuno Castro, Paula Chainho, Farrah Chan, Joel Creed, Amelia Curd, John Darling, Paul Fofonoff, Bella Galil, Chad Hewitt, Graeme Inglis, Inti Keith, Nicholas Mandrak, Agnese Marchini, Cynthia McKenzie, Anna Occhipinti-Ambrogi, Henn Ojaveer, Larissa Pires-Teixeira, Tamara Robinson, Gregory Ruiz, Kimberley Seaward … & Aibin Zhan
Aim The introduction of aquatic non-indigenous species (ANS) has become a major driver for global changes in species biogeography. We examined spatial patterns and temporal trends of ANS detections since 1965 to inform conservation policy and management. Location Global Methods We assembled an extensive dataset of first records of detection of ANS (1965-2015) across 49 aquatic ecosystems, including the i) year of first collection, ii) population status and iii) potential pathway(s) of introduction. Data were...

Increasing importance of niche versus neutral processes in the assembly of plant–herbivore networks during succession

Christopher Bosc & Anton Pauw
Recent studies suggest that the assembly of trophic interaction networks is the result of both niche (deterministic and selective) and neutral (stochastic) processes, but we know little about their relative importance. Succession following disturbance offers a good opportunity to address this question. Studies of single-trophic guilds suggest that, shortly after a disturbance, such as a fire, neutral assembly processes (e.g. colonisation events) dominate whereas niche processes (selection) become more and more important as succession proceeds....

Registration Year

  • 2020

Resource Types

  • Dataset
  • Data Paper


  • Stellenbosch University
  • University of Cape Town
  • Southwest Jiaotong University
  • Vellore Institute of Technology University
  • Murdoch University
  • University of Pavia
  • University of Orléans
  • Rio de Janeiro State University
  • University of Graz
  • Government of South Africa