Molecular phylogenetics, taxonomy and niche-based conservation risk assessment of Thesium L. (Santalaceae)

Thesium L. (Santalales: Santalaceae) is a large (360 species) genus of hemiparasitic perennial or annual species with a mainly Old-World distribution and a greatest concentration in southern Africa (ca. 186 species). Although Thesium is a major component of southern African flora, it often goes unnoticed and is poorly studied. The last revision of the entire genus was done by De Candolle in 1857. South African Thesium was last revised by Hill almost a century ago. Since Hill's revision, the number of collections have grown, and 49 new species have been described. Currently, no comprehensive Thesium taxonomic key exists, and species delimitation remains difficult due to a high variation in character states, rendering the genus in need of major revision. Within southern Africa, ca. 103 species occur in the Greater Cape Floristic Region (GCFR), of which about 72 are regional endemics. The GCFR Thesium, including ecologicalspecialists and generalists, offers an appropriate system for evaluating both the correlates of range extent, specialisation and the relative extinction risks associated with both ecological strategies. Here, it is predicted that a combination of edaphic, elevation and climate variables influence the geographic range of Thesium in the GCFR. Recent phylogenetic hypotheses revealed that Thesium is paraphyletic with respect to Austroamericium, Chrysothesium, Kunkeliella and Thesidium, suggesting the need for generic realignment. In addition, existing subgeneric and sectional classifications of this large genus lack a phylogenetic basis, thus compromising their predictive value. Using an expanded taxon sampling and a combination of nuclear (ITS) and chloroplast (matK, rpl32- trnL and trnL-F) DNA sequence data, chapter two re-assesses the phylogenetic relationships of Thesium and uses these as the basis of a new subgeneric classification of the genus. The phylogeny obtained confirms the need to place the four segregate genera into synonymy, resulting in a monophyletic Thesium. In addition, it resolves five, well-supported major clades within Thesiumwhich I recognize as subgenera. The South African endemic subgenus Hagnothesium is sister to the Eurasian subgenus Thesium (including Thesium, Kunkeliella and Mauritanica). The subgenus Psilothesium, occurring in tropical South America (formerly genus Austroamericium) and tropical Africa, is sister to the rest of the subgenera, which are all confined to South Africa. Within the latter, the subgenus Discothesium consists of subtropical and temperate species, whereas subgenus Frisea, comprising previously recognized sections Annulata, Barbata Frisea, Imberbia and Penicillata, is restricted to the GCFR. To facilitate identification of subgenera, I present identification keys, assigned species, provide brief diagnoses, identified ancestral morphological characters and, supply distribution and ecological data. Thesium subgenus Hagnothesium is endemic to the GCFR. In the past, there has been a propensity in revisionarywork ofthe subgenus Hagnothesium to split taxa into distinctspecies or vice-versa. Consequently, 15 different names exist although only six are accepted formally. Following recent molecular phylogenetic studies, the monophyly of the subgenus Hagnothesium is now well-established, but the circumscription of species within the section remains problematic given the complicated nomenclatural history which has added further confusion. Chapter three presents a revision of subgenus Hagnothesium using a total evidence approach to propose a modern taxonomy. I studied both herbarium collections and plants in their natural populations to circumscribe species boundaries, geographical ranges and estimates of their conservation status. Species of the subgenus Hagnothesium are dioecious, generally having four- merous, campanulate flowers, spikes borne in bract axils and arranged along the length of branchlets, with valvate perianth lobes and a short to absent hypanthial tube. The following eight species were recognized, of which one is here described as new: T. fragile L.f., T. fruticulosum (A.W.Hill) J.C.Manning & F.Forest, T. hirtum (Sond.) Zhigila, Verboom & Muasya comb. nov., T. leptostachyum A.DC., T. longicaule Zhigila, Verboom & Muasya nom. nov., T. microcarpum A.DC., T. minus (A.W.Hill)J.C.Manning & F.Forest and T. quartzicolum Zhigila, Verboom & Muasya sp. nov. I provide updated taxonomic keys, species descriptions, illustrations, distribution maps, new combinations, synonyms, and notes on the red list status for each species. In addition, six new species of Thesium endemic to the GCFR (but not included in subgenus Hagnothesium) are described and illustrated in chapter four. These are: Thesium aspermontanum Zhigila, Verboom & Muasya sp. nov., T. dmmagiae Zhigila, Verboom & Muasya sp. nov., T. neoprostratum Zhigila, Verboom & Muasya sp. nov., T. nigroperianthum Zhigila, Verboom & Muasya sp. nov., T. rhizomatum Zhigila, Verboom & Muasya sp. nov., and T. stirtonii sp. nov. Also, Thesium assimile var. pallidum is elevated to species rank as T. sawae Zhigila, Verboom & Muasya stat. nov. Morphological and ecological differences between species, along with their putative affinities, preliminary conservation status, phenology, etymology and distributional maps are presented. Narrow-ranged species are expected to be more at greater risk of extinction than generalists due to climate change. Such risk is greatest in biodiversity hotspots such as the GCFR, which house both ecological specialists and generalists. It was hypothesized that range size, ecological specialization and consequent climatically-modulated extinction-risk are all phylogenetic structured, such that climate change will precipitate a disproportionate loss of phylogenetic diversity. Past and future species distribution ranges were developed using MaxEnt models based on present-day occurrences and environmental conditions. There was a strong positive correlation between the ecological niche breadth of species, as determined by large-scale environmental variables, and their range extents. One hundred and one Thesium species were modelled, of which 71 species (83%) were predicted to have had broad range sizes during the Last Glacial Maxima, and 27 species (17%) recorded range contractions historically to the present. Similarly, 45 species (44%) will potentially expand their ranges, while 51 species (50%) are predicted to reduce their ranges in the future. Of the 65 species currently ranked as Least Concern or Data Deficient in the South African Red list, 24 species will likely shift into higher extinction risk categories. Interestingly, five ecological specialists (5%), although having experienced a range reduction from the LGM to the present, are predicted to persist in the face of future climate change. However, the range extent, ecological specialisation and extinction risk are phylogenetically random and therefore should have a negligible impact on the phylogenetic diversity of the GCFR Thesium. Overall, this study confirms the monophyly of the genus Thesium and sets its infrageneric classification scheme in place. The context of this classification framework allows the systematic revision of the genus, one clade at a time. Towards this goal, I revised the Hagnothesium clade and additionally described six new species from other clades. The climate, elevation and soil variables influence the distribution range and specialism of GCFR Thesium clades. However, ecological specialism of species and extinction risks were predicted to be phylogenetically random

Analysis of a Mathematical Model to Investigate the Dynamics of Dengue Fever

In this paper, we formulated a compartmental model to investigate the dynamics of dengue fever in a population with some measure of disease control. We qualitatively and quantitatively analyzed the model and found that the model has a disease free equilibrium (DFE), an endemic equilibrium point and undergoes the phenomenon of backward bifurcation. It was also discovered that Dengue can be eliminated irrespective of the initial size of the infected population whenever the effective reproduction number is less than one. Numerical simulations were carried out on the model and effective control measures were proposed that will result in reducing the burden of the disease in the population.Keywords: Dengue Fever, Mathematical Model, Equilibrium, Bifurcation analysis, Effective reproduction number, Stability

Wind turbine maintenance optimisation: principles of quantitative maintenance optimisation.

Maintenance optimisation is a crucial issue for industries that utilise physical assets due to its impact on costs, risks and performance. Current quantitative maintenance optimisation techniques include Modelling System Failures MSF (using monte-carlo simulation) and Delay-Time Maintenance Model (DTMM). The MSF investigates equipment failure patterns by using failure distribution, resource availability and spareholdings to determine optimum maintenance requirements. The DTMM approach examines equipment failure patterns by considering failure consequences, inspection costs and the period to determine optimum inspection intervals. This paper discusses the concept, relevance and applicability of the MSF and DTMM techniques to the wind energy industry. Institutional consideration as well as the benefits of practical implementation of the techniques are highlighted and discussed

‘Of Holy Names’ and Integrity in Business in the Contemporary Nigerian Society

Business and commercial outfits are named after divine names and attributes of God. Hardly will one visit or take a walk around any city in Nigeria without noticing commercial outfits or businesses named after God. Be that as it may, one will expect such businesses and owners to be of highly infectious integrity! But that make not be the case, as wrong measures, shortfalls and cutting-corners are the order of the day in businesses in Nigeria. This study, therefore, looks at businesses that have a religious connotation in their registration identity and Christian businessmen and women; with a view of assessing them from the biblical injunction of integrity in business and how faithful they are to what they professed. Purposive selection of businesses that have divine affiliation and one hundred samples of those who patronise them will form the fulcrum of this work. The questionnaire used was interpreted and analysed through descriptive statistics It is believed that whosoever is named with God should depart from 'iniquity' and live up to the expectation of what they believed and confessed, to be a shining light to others as the Bible enjoins

A critique of discrimination on the basis of poverty in the Epistle of James : a case study of the Church of the Brethren Gavva Area.

Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.This thesis argues that the Epistle of James provides the resources that will address the problem of discrimination and exploitation in the Church of the Brethren in Gavva area. In order to argue this, I establish that Gavva area is a peasant society. I argue that the Epistle of James addresses the situation of the peasants in the first century Palestine. The peasants were discriminated against and exploited by the wealthy and the elites in James’ time. This prompts James to condemn the wealthy landowners and the merchants for their attitude toward the peasants. I examine the Epistle against the model of the moral economy developed by Sahlins and modified by Moxnes in The Economy of the Kingdom (1988). They delineate three categories of reciprocity: generalized, balanced and negative reciprocity. These are used as the basis of analysis of James and then extended also to an analysis of the moral economy of the Church of the Brethren in Nigeria. Further empirical study reveals that the poor in Gavva area are living in poverty and are discriminated against because they did not have opportunity to receive early educational training that might have equipped them to hold positions in the church and society. The concepts of poverty of Klaus Nürnberger, Amartya Sen, Bryant Myer and Adarigho-Oriako have also assisted me in evaluating the problem of poverty of Gavva area. Since Gavva area is, like the community to which the Epistle of James is addressed, an analysis of peasants and their moral economy, clientage and patronage, honour and shame are vital to my research. In this respect, the work of James C. Scott in Domination and Art of Resistance: the Hidden Transcript (1990) has proved valuable in my analysis of the way the poor in Gavva area are dominated by the wealthy. The poor develop resistance to the church leadership and the wealthy in their “hidden transcript” developed “off stage.” In this research, I discovered that the Church of the Brethren in Nigeria has official documents on discrimination, poverty, the poor and how to take care of them, which should direct their economic policy. But the church leadership does not enforce the teachings in the documents because of contending socio-economic forces and personal interests. I also find that the problem originated in the circumstances of the merger¹ I have explained what the merger means in chapter 5. which was complicated by tribalism that is present in the church. The major tribes seem to dominate every aspect of the church leadership and its programmes and institutions. As a possible contribution to addressing the problems of discrimination, exploitation and tribalism in the church, I published Bible study material from my research findings with an emphasis on the Epistle of James. The church will use the Bible study outline to conduct Bible study in all the Local Church Councils (LCC) throughout Nigeria. My hope is that the Bible study will bring the wealthy, the poor, the pastors/church leaders and the different tribes together so that church members will come together as one and pastors and church leaders will nolonger give preferential treatment to the wealthy members but see themselves as members of one community and treating one another as equals. The pastors would not give preferential treatment to the wealthy and the wealthy would honour the poor. ¹ I have explained what the merger means in chapter 5

Sensitivity Analysis of a Mathematical Modeling of Ebola Virus Population Dynamics in the Presence of Vaccine

The virus (Ebola virus) (EBV) belongs to the Filoviri-dae family which is a filovirus and is a serious disease which  leads to hemorrhagic disease in human and non human such as chimpanzee, gorilla, porcupine, fruit bats etc. In  this paper, a mathematical modeling for the population dynamics of EBV diseases in the presence of vaccination  was developed. The research shows that, using the human control reproduction number ( Rc )as response and  infectious individual as response function, that the sensitive parameters in the formulated system (1) are the  personal hygiene (ε ), humans to human contact rate ( β1 ), modification parameter (η ), human vaccination rate ( ρ ), proper burial (φ ) and humans natural mortality rate (μh ). The study shows that personal hygiene rate, effective  contact rate of humans, natural mortality of humans’ rate, vaccination rate and proper burial rate are very sensitive  to both reproduction number and infectious humans.&nbsp

Optimal control of mathematical modelling for Ebola virus population dynamics in the presence of vaccination

Ebola virus is a severe often fatal illness in human, which is known to be very dangerous and highly infectious disease that seized many lives in west African countries. In this paper, a mathematical model for the population dynamics of Ebola virus diseases incorporating bats compartment, recovery due to immune response and vaccination was constructed. Pontryagin’s maximum principle has been applied on the model to determine the necessary conditions for the optimal control of the Ebola virus in the presence of vaccination and fruit bats population, the optimality of most of the controls have been analyzed to use a small resources available in other to maximize the performance of the controls. The numerical simulation shows that with small resources if 0.1 percent of the people in a society can be vaccinated daily, Ebola can be mitigated in the environment

Maintenance optimisation for wind turbines.

Wind is becoming an increasingly important source of energy for countries that ratify to reduce the emission of greenhouse gases and mitigate the effects of global warming. Investments in wind farms are affected by inter-related assets and stakeholders requirements. These requirements demand a well-founded Asset Management (AM) frame-work which is currently lacking in the wind industry. Drawing from processes, tools and techniques of AM in other industries, a structured model for AM in the wind industry is developed. The model divulges that maintenance is indispensable to the core business objectives of the wind industry. However, the common maintenance strategies applied to wind turbines are inadequate to support the current commercial drivers of the wind industry. Consequently, a hybrid approach to the selection of a suitable maintenance strategy is developed. The approach is used in a case study to demonstrate its practical application. Suitable Condition-Based Maintenance activities for wind turbines are determined. Maintenance optimisation is a means to determine the most cost-effective maintenance strategy. Field failure and maintenance data of wind turbines are collected and analysed using two quantitative maintenance optimisation techniques; Modelling System Failures (MSF) and Delay-Time Maintenance Model (DTMM). The MSF permits the evaluation of life-data samples and enables the design and simulation of a systems model to determine optimum maintenance activities. Maximum Likelihood Estimation is used to estimate the shape (β) and scale (η) parameters of the Weibull distribution for critical components and subsystems of the wind turbines. Reliability Block Diagrams are designed using the estimated β and η to model the failures of the wind turbines and of a selected wind farm. The models are simulated to assess and optimise the reliability, availability and maintainability of the wind turbine and the farm. The DTMM examines equipment failure patterns by taking into account failure consequences, inspection time and cost in order to determine optimum inspection intervals. Defects rate (α) and mean delay-time (1/γ) of components and subsystems within the wind turbine are estimated. Optimal inspection intervals for critical subsystems of the wind turbine are then determined

Optimisation of wind turbine inspection intervals.

The choice of correct inspection intervals poses a serious challenge to industries that utilise physical assets. Too short an interval increases operational cost and waste production time while too long an interval increases the likelihood of unexpected asset failures. Failure Modes and Effect Criticality Analysis (FMECA) is a technique that permits qualitative evaluation of assets' functions to predict critical failure modes and the resultant consequences to determine appropriate maintenance tasks for the assets. The Delay-Time Maintenance Model (DTMM) is a quantitative maintenance optimisation technique that examines equipment failure patterns by taking into account failure consequences, inspection time and cost in order to determine optimum inspection interval. In this paper, a hybrid of FMECA and DTMM is used to assess the failure characteristics of a selected subsystems of a chosen wind turbine. Optimal inspection intervals for critical subsystems of the wind turbine are determined to minimise its total life-cycle cost

The selection of a suitable maintenance strategy for wind turbines.

Common maintenance strategies applied to wind turbines include 'Time-Based' which involves carrying out maintenance tasks at predetermined regular-intervals and 'Failur-Based' which entails using a wind turbine until it fails. However, the consequence of failure of critical components limits the adequacy of these strategies to support the current commercial drivers of the wind industry. Reliability-Centred Maintenance (RCM) is a technique used mostly to select appropriate maintenance strategies for physical assets. In this paper, a hybrid of an RCM approach and Asset Life-Cycle Analysis technique is applied to Horizontal-Axis Wind Turbines to identify possible failure modes, causes and the resultant effects on system operation. The failure consequences of critical compenents are evaluated and expressed in financial terms. Suitable Condition-Based Maintenance activities are identified and assessed over the life cycle of wind turbines to maximise the return on investment in wind farms