The development of a risk index for depression (RID)

&nbsp;This thesis developed a novel methodology for a flexible and modular Risk Index for Depression (RID) that blended data mining and machine learning techniques with traditional statistical techniques. This RID shows great potential for future clinical use.<br /

The application of digital soil mapping to improve the resolution of national soil properties across Great Britain.

Many countries have created soil maps to illustrate the variety of soil properties and support how soils can be used. Traditional soil mapping by field survey and interpretation has been the most recognised form of soil mapping for many years and an effective way to capture a variable soil landscape. Such maps have enabled scientists and stakeholders to improve their understanding of relationships between soils and other landscape factors such as geology and land cover. However, with the amount of soil information growing and technology improving, Digital Soil Mapping (DSM) has been developed as an alternative approach to generate soil property predictions and to produce finer resolution soils data. Currently, DSM produces maps based on training of models with observed soils data and environmental covariates and then releases these to stakeholders to evaluate their utility. This PhD has taken a different approach by addressing stakeholder needs at the beginning of the process. The overall aim of this PhD was to improve the spatial resolution of soil properties across Great Britain (GB), as informed by stakeholders. Three main aims were identified. The first assessed what current soils data and information stakeholders currently use, and what improvements they want to see from future soil-related products. The second aim, using information from the questionnaire survey and a comparison of laboratory and analytical methods, is to develop DSM which could be applied across the whole of GB. This was done by comparing two modelling approaches: Boosted Regression Trees (BRTs) and Multivariate Adaptive Regression Splines (MARS) for mapping soil properties (loss-on-ignition, texture and pH) across two pilot areas. The characteristics of MARS and BRT models at both training and deployment stages are examined. The third outcome investigated how well the soil properties mapped across GB, building on the development of DSM in the pilot areas and whether they reflect expert pedological knowledge. This section also focusses on how suitable an independent validation dataset is at evaluating soil property predictions. This PhD has shown that stakeholders are aware of what soils data and information they are using and could clearly express what is needed to improve current maps. Wider use of soil information by non-soil experts would be improved by increasing data accessibility and user- friendly supporting materials. Fundamentally, most stakeholders require finer resolution than what is currently available which identifies an opportunity for DSM to fill some of this gap. To address these gaps and develop DSM across GB, this PhD focussed on mapping soil properties that were directly comparable across Scotland and England & Wales and also key to many stakeholder information needs. After investigation of laboratory and analytical methods from the two national soil surveys of Scotland and England & Wales, soil loss on ignition, soil texture and soil pH were chosen for developing DSM for GB. From the development of DSM, results showed that MARS models produced better statistical performances than BRTs for predicting soil properties within a training environment. However, when MARS models are deployed to larger areas, they extrapolate beyond their means and BRTs performed better. This is because MARS models perform more consistently when many variables are required. Furthermore, MARS models struggle with overfitting and missing data which subsequently leads to incorrect and unfeasible pedological relationships between soil properties. BRT models, despite not performing as well statistically, produce more consistent relationships between pedology and mapped soil properties. This is because BRT models introduce randomness in the boosting which reduces overfitting and improves the predictive performance. BRTs have shown to be more consistent in the mapping outputs than MARS because regressing to the mean is more favourable when most data matches up with one another. However, this does not necessarily mean that the full range of soils in these areas were being captured by the BRT model. This led to scaling up from the pilot areas to modelling soil properties across GB using a single regional BRT model and evaluating its performance. BRT modelling results for GB at 2D and 3D predict well for pH and LOI but less so for texture. Going forward, more data are required to produce more consistent modelling outputs especially for areas across GB where soil properties are not currently being predicted well. The GB modelling results also highlighted a poor performance of the model against an independent validation dataset. This is because the original data for both GB training and validation datasets were analysed and collected for different purposes. These datasets were taken at different time periods under a different sampling design. Furthermore, the data for both training and validation GB datasets were collected at different scales. At present, these first versions of soil property DSM maps for GB have produced variable results. However, this exercise has shown that the development of reliable DSM maps would benefit from interaction between pedologists, modellers and stakeholders to ensure that mapped outputs are of sufficient quality at adequate finer resolution and can be usable. Such DSM maps, alongside management recommendations, will help to address many global challenges associated to soils. However, DSM is not the panacea for all mapping needs. Until such time that DSM fully develops into DSA and adequately incorporates the breadth of information available in traditional soil maps, mapping from field survey and observation will continue to be necessary for stakeholders.Engineering and Physical Sciences (EPSRC)PhD in Environment and Agrifoo

Estimating UK House Prices using Machine Learning

House price estimation is an important subject for property owners, property developers, investors and buyers. It has featured in many academic research papers and some government and commercial reports. The price of a house may vary depending on several features including geographic location, tenure, age, type, size, market, etc. Existing studies have largely focused on applying single or multiple machine learning techniques to single or groups of datasets to identify the best performing algorithms, models and/or most important predictors, but this paper proposes a cumulative layering approach to what it describes as a Multi-feature House Price Estimation (MfHPE) framework. The MfHPE is a process-oriented, data-driven and machine learning based framework that does not just identify the best performing algorithms or features that drive the accuracy of models but also exploits a cumulative multi-feature layering approach to creating machine learning models, optimising and evaluating them so as to produce tangible insights that enable the decision-making process for stakeholders within the housing ecosystem for a more realistic estimation of house prices. Fundamentally, the MfHPE framework development leverages the Design Science Research Methodology (DSRM) and HM Land Registry’s Price Paid Data is ingested as the base transactions data. 1.1 million London-based transaction records between January 2011 and December 2020 have been exploited for model design, optimisation and evaluation, while 84,051 2021 transactions have been used for model validation. With the capacity for updates to existing datasets and the introduction of new datasets and algorithms, the proposed framework has also leveraged a range of neighbourhood and macroeconomic features including the location of rail stations, supermarkets, bus stops, inflation rate, GDP, employment rate, Consumer Price Index (CPIH) and unemployment rate to explore their impact on the estimation of house prices and their influence on the behaviours of machine learning algorithms. Five machine learning algorithms have been exploited and three evaluation metrics have been used. Results show that the layered introduction of new variety of features in multiple tiers led to improved performance in 50% of models, a change in the best performing models as new variety of features are introduced, and that the choice of evaluation metrics should not just be based on technical problem types but on three components: (i) critical business objectives or project goals; (ii) variety of features; and (iii) machine learning algorithms

Aliens in the nursery : assessing the awareness and attitudes of Cape Town nursery managers in regard to invasive species regulations

The horticultural industry is recognised as one of the major pathways for the introduction and spread of invasive alien plants (IAPs). In recognition of this, the South African government has recently enacted a new set of Alien and Invasive Species regulations, under the National Environmental Management Biodiversity Act (NEMBA), that are intended, in part, to improve controls on the horticultural industry's role in the spread of IAPs. In order to assess, and possibly enhance, the likely effectiveness of NEMBA, it is critical to build an understanding of stakeholders' awareness and attitudes towards the control of IAPs and associated regulatory policies. A two-pronged approach – involving nursery manager interviews (n=30) and plant stock audit assessments (n=41) - was used to gauge the awareness, compliance and attitudes of Cape Town nursery managers towards the NEMBA regulations. Results showed that less than ten percent of the city's audited nurseries were compliant with the NEMBA regulations, and that over fifty percent were stocking IAPs that have been regulated for at least thirteen years under a previous set of regulations (the Conservation of Agricultural Resources Act, CARA). This is despite high levels of awareness about the CARA regulations reported in the interviews, reported enthusiasm for compliance, apparent concern for the environment, evidence that managers understand the problems that IAPs cause, extensive reported support for the control of IAPs, and a reportedly strong sense of duty to protect the environment. The vast majority (73.5%) of IAP species found in nurseries were NEMBA category 1b invaders such as Nerium oleander, Lantana montevidensis and Canna indica. These are species that are widespread and well-established invaders that require control. This study suggests that a range of factors are likely to negatively influence compliance including a perceived lack of enforcement, weak communication from government, issues related to the clarity of the regulations, the lack of inclusion of the industry in the regulatory process, and a lack of awareness, with at least half of the managers reporting that they had not heard about the enactment of NEMBA. Any attempt to improve the impact of the new regulations will need to adequately address each of these factors. The results of the study suggest that enhancing the impact of NEMBA will require improving aspects of the legislation itself, and supplementing the current top-down approach to regulation with an inclusive partner-centred approach

Better lives for all? : prospects for empowerment through marine wildlife tourism in Gansbaai, South Africa : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Development Studies at Massey University, Manawatū, Aotearoa New Zealand

Little is known about the consequences of burgeoning commercial marine wildlife tourism (MWT) for communities in the Global South. Gansbaai, the location for this research, has a concentration of twelve MWT operators; it also faces the triple challenge of unemployment, poverty, and inequality. Given their privileged access to marine common resources, empowerment and tourism policies position MWT permit holders as key agents of development. This research examines how MWT contributes to development for less advantaged residents of Gansbaai. Here, development means better lives and sustained empowerment for residents and rebalanced power relationships between social actors. A novel Tourism-Empowerment Framework guided observation and analysis of empowerment interfaces, expressions of power, and empowerment processes and outcomes in MWT. A mixed methods approach drew on administrative data, participant observation, and interviews with civil society, private sector, and government actors. Crucially, the results revealed government actions, persistent societal power imbalances, and structural constraints circumscribed prospects for empowerment through MWT operators. Therefore, the ability of private firms to advance empowerment was restricted. Nevertheless, the results show how business processes advanced empowerment in several dimensions for most residents linked to operators. Substantial investment in human and local economic development by some MWT operators meant benefits extended beyond business owners and employees. Empowerment manifested as strengthened ability and agency to attain personal goals through decent work, increased household resources, enhanced skills and self-confidence, expanded social capital, strengthened collective power, and greater influence over decisions that affect their lives. Further, most less advantaged residents of Gansbaai were marginalised from the multidimensional benefits of MWT, and some people experienced disempowerment. Many interventions were operator-defined, charity-based, prioritised business benefits, and maintained power imbalances. Altogether, the findings suggest unequal empowerment, uneven impact on the six dimensions of empowerment, simultaneous empowerment and disempowerment, and a muted effect on structural transformation. In the final analysis, while MWT appears to have progressed multi-dimensional empowerment for some residents, claiming that MWT has led to rebalanced power relations and better lives for all less advantaged residents of Gansbaai would be disingenuous

Surveillance and Response to Infectious Diseases and Comorbidities: An African and German Perspective

Cite: Academy of Science of South Africa (ASSAf), (2019). Surveillance and Response to Infectious Diseases and Comorbidities: An African and German Perspective [Available online] DOI http://dx.doi.org/10.17159/assaf.2019/0042The conference explored various topics pertaining to Infectious Diseases and Comorbidities. These included: antimicrobial resistance; one health; HIV; TB; Malaria; and HCV. The objectives of the symposium were to scientifically analyse challenges pertaining to infectious diseases and comorbidities as they relate to surveillance, responses and diagnostics; identify current and future research needs that can be employed to tacle emrging scientific challenges; Assess possible solutions to current challenges as they relate to surveillance and response to infectious diseases and morbidities and how these can be used to provide science advice to governments; and, exchange scientific information between young and senior scientists from the sub-Saharan Africa and Germany.Academy of Science of South Africa (ASSAf

Perceived decision making factors in the use of traditional and alternative medicine for people living with HIV and AIDS

AIDS is one of the most destructive diseases humankind has ever faced and also brings with it profound social, economic and public health consequences, making it one of the most serious health and development challenges in the world today. Zimbabwe, situated in southeastern Africa, is not spared from the pandemic. It continues to be one of the Sub-SaharanAfrican countries mostly heavily impacted by the AIDS epidemic, with almost 1.2 million people infected and over 1.1 million orphans. It ranks, therefore, as fifth highest in the world in the impact HIV and AIDS has had on the country. The most effective response has been to introduce programmes to reduce the number of new infections. Recent research has demonstrated treatment as a preventative measure to be very effective. This approach involves targeting those who are infected so that they are not able to transmit the disease. The decision that has to be made by an infected person, however, is whether to look for traditional treatment, conventional treatment or a combination of the two. Herbal medicine use is becoming very common in many countries, especially in the developing world, where public health safety has become a concern. It has become common to use herbal medicine concomitantly with allopathic or conventional medicine. The present study focused on investigating perceptions leading to the choice of treatment with the traditional alternative medicines (TAM) as (a)/n alternative or compliment to the conventional or allopathic option. This is a qualitative study that explores and describes participant’s perceptions, beliefs, attitudes and feelings around the use of traditional medicine, within the context of the Integrative Behaviour Model (IBM). Data was collected from 20 people living with HIV and AIDS from urban and rural settings of different ethnicities (Shona and Shangani). The data analysis was informed by The Interpretive Phenomenological Analysis with the aid of NVivo (V.10), a computer-assisted Qualitative Data Analysis Software. As predicted by the IBM, both perceived individual and environmental factors were found to be key in influencing decision-making on the use of TAM by people living with HIV and AIDS. Although there were a number of incidents in which either individual or environmental factors were perceived as independently influencing the TAM-use decision-making process, there was a lot of mutual influence between the environment and the individual. Such mutual causation was abstracted as reciprocal determinism. The IMB model assumed a unidirectional causation in which the environment could affect the individual factors. While the present study identified and demonstrated these environmental effects on the individual, it also identified and presented a reverse causation in which the individual would also affect the environment with respect to motivation for TAM use. Individual factors were psychological properties that drove the individual to use TAM. Attitude, social influence and personal agency emerged as the three dimensions of individual factors. Attitudes helped in identification of orientations that located objects of thought on dimensions of judgment about the use of TAM. Social influence explained social pressure experienced and expected regarding the use of TAM. The study demonstrated the importance of both the descriptive and injunctive norm with participants indicating that they perceived important others to be using traditional medicine and that they felt perceived expectations from others to do the same and hence the motivation to comply. Personal agency pointed to the participants’ capacities to originate and direct actions for the purposes of TAM use. All these constructs were found to be very important as perceived determinants of the behavioral intentions of people living with HIV and AIDS to use traditional medicines. In experiential attitude, generally the respondents showed more perceived positive evaluations of pleasurable experiences in their use of traditional medicines. However, there were other outcome evaluations that seemed to be ambivalent and which appeared to cause a lot of tension. The comprehension of experiential attitude was found therefore found to be trichotomous rather than dichotomous as per the IBM. The effects of the instrumental attitude were revealed in the ratings of the extent to which the use of traditional medicine was perceived as useful or rewarding, with the study revealing high ratings of usefulness. It becomes clear, therefore, that for people living with HIV and AIDS social influence, perceived attitudes and personal agency are important decision-making factors in their use of traditional and alternative medicine. Efforts towards education, integration and behaviour change programmes should design messages targeting these behavioral determinants. Understanding of these perceived determinants is crucial to influencing policy as well as the adoption of health practices through education, marketing and other modes of health promotion