Research Articles (Mathematical Sciences)
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A simulation agespecific tuberculosis model for the Cape Town metropole
(Academy of Science of South Africa, 20130918)Tuberculosis (TB) continues to present an insurmountable health burden in the Western Cape Province of South Africa. TB dynamics in adults is different from that in children, with the former determining the latter. Because ...

Invading a mutualistic network : to be or not to be similar
(Wiley Open Access, 2016)Biological invasion remains a major threat to biodiversity in general and a disruptor to mutualistic interactions in particular. While a number of empirical studies have directly explored the role of invasion in mutualistic ...

A geometrical model for testing bilateral symmetry of bamboo leaf with a simplified Gielis equation
(Wiley Open Access, 2016)The size and shape of plant leaves change with growth, and an accurate description of leaf shape is crucial for describing plant morphogenesis and development. Bilateral symmetry, which has been widely observed but poorly ...

The seesaw effect of winter temperature change on the recruitment of cotton bollworms Helicoverpa armigera through mismatched phenology
(John Wiley & Sons Ltd., 2015)Knowing how climate change affects the population dynamics of insect pests is critical for the future of integrated pest management. Rising winter temperatures from global warming can drive increases in outbreaks of some ...

An optimal proportion of mixing broadleaved forest for enhancing the effective productivity of moso bamboo
(John Wiley & Sons Ltd., 20150317)Moso bamboos (Phyllostachys edulis) are important forestry plants in southern China, with substantial roles to play in regional economic and ecological systems. Mixing broadleaved forests and moso bamboos is a common ...

Thermodynamics analysis of variable viscosity hydromagnetic Couette flow in a rotating system with Hall effects
(MDPI, 20151120)In this paper, we employed both first and second laws of thermodynamics to analyze the flow and thermal decomposition in a variable viscosity Couette flow of a conducting fluid in a rotating system under the combined ...

Social and genetic networks of HIV1 transmission in New York City
(PLoS, 20170109)Background Sexually transmitted infections spread across contact networks. Partner elicitation and notification are commonly used public health tools to identify, notify, and offer testing to persons linked in these ...

Modelling the trends of inpatient and outpatient rehabilitation for methamphetamine in the Western Cape province of South Africa
(BioMed Central, 20151218)Background: Dependence on methamphetamine remains one of the major health and social problem in the Western Cape province of South Africa. We consider a mathematical model that takes into account two forms of rehabilita ...

On the transmission dynamics of Buruli ulcer in Ghana : insights through a mathematical model
(BioMed Central, 20151106)Background: Mycobacterium ulcerans is know to cause the Buruli ulcer. The association between the ulcer and environmental exposure has been documented. However, the epidemiology of the ulcer is not well understood. ...

Computational and theoretical analysis of human diseases associated with infectious pathogens
(Hindawi, 2015)Mathematical models and computer simulations are useful experimental tools for building and testing theories, assessing quantitative conjectures, answering specific questions, determining sensitivities to changes in parameter ...

On the validity of evolutionary models with sitespecific parameters
(PLoS, 20140410)Evolutionary models that make use of sitespecific parameters have recently been criticized on the grounds that parameter estimates obtained under such models can be unreliable and lack theoretical guarantees of convergence. ...

Zeta diversity as a concept and metric that unifies incidencebased biodiversity patterns
(The University of Chicago Press, 201411)Patterns in species incidence and compositional turnover are central to understanding what drives biodiversity. Here we propose zeta (ζ) diversity, the number of species shared by multiple assemblages, as a concept and ...

Spatial assortment of mixed propagules explains the acceleration of range expansion
(Public Library of Science, 201408)Abstract Range expansion of spreading organisms has been found to follow three types: (i) linear expansion with a constant rate of spread; (ii) biphase expansion with a faster linear expansion following a slower linear ...

On new high order quasilinearization approaches to the nonlinear model of catalytic reaction in a flat particle
(Hindawi Publishing Corporation, 2013)A novel computational approach known as pseudospectral quasilinearization (SQLM) is employed to tackle the twopoint boundary value problem describing the reactivity behaviour of porous catalyst particles subject to both ...

Entropy generation in a couple stress fluid flow through a vertical channel filled with saturated porous media
(MDPI, 20131025)The present work investigates numerically the inherent irreversibility in a steady flow of a couple stress fluid through a vertical channel packed with saturated porous substances. The First and Second Laws of Thermodynamics ...

Model checking rational agents
(IEEE  Institute of Electrical and Electronics Engineers, 200410)Agentoriented programming techniques seem appropriate for developing systems that operate in complex, dynamic, and unpredictable environments. We aim to address this requirement by developing modelchecking techniques for ...

Propertybased slicing for agent verification
(Oxford University Press (OUP), 200912)Programming languages designed specifically for multiagent systems represent a new programming paradigm that has gained popularity over recent years, with some multiagent programming languages being used in increasingly ...

A survey of new trends in symbolic execution for software testing and analysis
(Springer Verlag, 200910)Symbolic execution is a wellknown program analysis technique which represents program inputs with symbolic values instead of concrete, initialized, data and executes the program by manipulating program expressions involving ...

Left ventricular segmentation from MRI datasets with edge modelling conditional random fields
(BioMed Central, 201307)Background: This paper considers automatic segmentation of the left cardiac ventricle in short axis magnetic resonance images. Various aspects, such as the presence of papillary muscles near the endocardium border, makes ...

NonNegative Matrix Factorization for Learning AlignmentSpecific Models of Protein Evolution
(PLOS, 20111222)Models of protein evolution currently come in two flavors: generalist and specialist. Generalist models (e.g. PAM, JTT, WAG) adopt a onesizefitsall approach, where a single model is estimated from a number of different ...

Codon test : modeling amino acid substitution preferences in coding sequences
(PLOS Computational Biology, 201008)Codon models of evolution have facilitated the interpretation of selective forces operating on genomes. These models, however, assume a single rate of nonsynonymous substitution irrespective of the nature of amino acids ...

Modeling HIV1 drug resistance as episodic directional selection
(PLOS Computational Biology, 201105)The evolution of substitutions conferring drug resistance to HIV1 is both episodic, occurring when patients are on antiretroviral therapy, and strongly directional, with sitespecific resistant residues increasing in ...

Correcting the bias of empirical frequency parameter estimators in codon models
(Public Library of Science  PLOS, 201007)Markov models of codon substitution are powerful inferential tools for studying biological processes such as natural selection and preferences in amino acid substitution. The equilibrium character distributions of these ...

The geometry of unitary 2representations of finite groups and their 2characters
(Springer Link, 201102)Motivated by topological quantum field theory, we investigate the geometric aspects of unitary 2representations of finite groups on 2Hilbert spaces, and their 2characters. We show how the basic ideas of geometric ...

Francis Guthrie : a colourful life
(Springer, 201209)In 1852, in London, Francis Guthrie posed the question of colouring a map with four colours only, the question that eventually became known as the Four Colour Problem. The problem is famous, but what else do we know of ...

Realization of abstract convex geometries by point configurations
(Elsevier, 201001)The EdelmanJamison problem is to characterize those abstract convex geometries that are representable by a set of points in the plane. We show that some natural modification of the EdelmanJamison problem is equivalent ...

The asymptotic number of binary codes and binary matroids
(Society for Industrial and Applied Mathematics (SIAM), 200608)The asymptotic number of nonequivalent binary ncodes is determined. This is also the asymptotic number of nonisomorphic binary matroids on n elements.

Modelling the South African fruit export infrastructure : a case study
(Operations Research Society of South Africa, 2006)A description is provided of work performed as part of the fruit logistics infrastructure project commissioned by the South African Deciduous Fruit Producers’ Trust and coordinated by the South African Council for ...

Die SuidAfrikaanse uitgebreide maritieme gebied : ’n alternatiewe metode vir die bepaling van die voet van die kontinentale helling
(AOSIS OpenJournal, 2006)Kuslande het ’n eenmalige geleentheid om by die Verenigde Nasies (VN) aansoek te doen om ’n uitgebreide maritieme gebied, indien hul wetenskaplik kan toon dat die voet van die kontinentale helling (VKH) buite hul soewereine ...

Decomposing the hypercube Qn into n isomorphic edgedisjoint trees
(Elsevier, 201202)The problem of finding edgedisjoint trees in a hypercube arises for example in the context of parallel computing [3]. Independently of applications it is of high aesthetic appeal. The hypercube of dimension n, denoted ...