Pesticide-Leaf Interactions and Their Implications for Pesticide Fate Modeling

The work described here provides measured data to improve the understanding of the interaction between a pesticide and leaf surface after application. Two methods were developed, one using a newly introduced instrument, for the extraction of pesticides from leaves. This is required to measure the concentration of pesticide in the leaves. Using one of the developed extraction methods, measurements were made to determine how a pesticide equilibrates between a leaf and the air above it. These measurements were incorporated into a pesticide fate model that predicts how a pesticide moves through the environment after application to an agricultural field. The updated fate model was used to predict the danger the pesticide posed to honeybees

Assessing the potential impact of climate change in the south-eastern Great Escarpment, Southern Africa

Rapid, anthropogenic climate change is a contemporary phenomenon which is threatening natural ecosystems. Mountains are globally important, housing high levels of plant and animal biodiversity, as well as being important suppliers of water with 50% of mountainous regions being essential for the provision of water to downstream inhabitants. Owing to their importance, an assessment of the historical, current and potential impacts of climate change on the south-eastern Great Escarpment encompassing South Africa and Lesotho is necessary and is the primary aim of this thesis. In order to assess the historical and current impacts of climate change, historical rainfall records were collected from 78 sites throughout the Eastern Cape. These records were used to determine rainfall trends and trends in the frequency of daily extreme events. Climate change projections predict increasing trends in summer and annual rainfall, and a marginal increase to a slightly decreasing trend in winter rainfall, depending on if statistically downscaled or dynamically downscaled projections are examined. Extreme events are also predicted to increase in frequency. Results showed trends which generally agree with the predictions, except for extreme events for which there was insufficient data to support the projections. This has implications for farmers in the area and validates the downscaled Regional Climate Models (RCMs) to be used for the predictive analysis determining the potential future impacts of climate change on plant species' distributions in the south-eastern Great Escarpment. In order to assess montane plant species to future climate predictions, occurrence records of 46 species were correlated to rainfall and temperature predictor variables and predictions for species richness and beta diversity were made for current and future climates. This predictive analysis used and compared two correlative species distribution modelling methods - one method used one correlating algorithm in a nuanced manner and the other method used five correlating algorithms in an ensemble. A trend of range restriction to higher elevations for the 46 species analysed was as expected from a warming climate. The nuanced, single algorithm modelling method produced less conservative models. The predicted trend of an elevational increase in montane vegetation in this region points to Lesotho and the Drakensberg highlands as being an important refugium for montane plant taxa of the southeastern Great Escarpment. The Maloti Drakensberg Transfrontier Conservation Area hence needs to be expanded and its mandate properly enforced to protect this region adequately

The Design and Implementation of a Toolkit for the Creation of Virtual Environments

Virtual Reality is a field that is steadily increasing in popularity and interest. New developments in both hardware and software have empowered developers with new devices allowing faster and better quality interaction with virtual environments. However, the emphasis of research in virtual environments has been more concerned with development of new display and input devices, as opposed to the investigation of different methods of interaction that a three-dimensional environment offers. This project designs and implements a three-dimensional, interactive, virtual environment development system upon an existing three-dimensional rendering engine. The aim of the project is to allow users to generate virtual environments with ease through a simple and intuitive user interface. Support for a gesture-based input device has been provided, as well as for more conventional two-dimensional input devices such as the mouse and joystick. By catering for a variety of input devices, various different forms of input have been examined in terms of their strengths and weaknesses. It is through the use of techniques developed throughout this project that designers of virtual environments may go about their work with greater efficiency and simplicity, allowing users to concentrate on the development of the environment, rather than being limited by the tools they possess

Emergency laparoscopy – current best practice

Emergency laparoscopic surgery allows both the evaluation of acute abdominal pain and the treatment of many common acute abdominal disorders. This review critically evaluates the current evidence base for the use of laparoscopy, both diagnostic and interventional, in the emergency abdomen, and provides guidance for surgeons as to current best practise. Laparoscopic surgery is firmly established as the best intervention in acute appendicitis, acute cholecystitis and most gynaecological emergencies but requires further randomised controlled trials to definitively establish its role in other conditions

Trust Region Methods for Training Neural Networks

Artificial feed-forward neural networks (ff-ANNs) serve as powerful machine learning models for supervised classification problems. They have been used to solve problems stretching from natural language processing to computer vision. ff-ANNs are typically trained using gradient based approaches, which only require the computation of first order derivatives. In this thesis we explore the benefits and drawbacks of training an ff-ANN with a method which requires the computation of second order derivatives of the objective function. We also explore whether stochastic approximations can be used to decrease the computation time of such a method. A numerical investigation was performed into the behaviour of trust region methods, a type of second order numerical optimization method, when used to train ff-ANNs on several datasets. Our study compares a classical trust region approach and evaluates the effect of adapting this method using stochastic variations. The exploration includes three approaches to reducing the computations required to perform the classical method: stochastic subsampling of training examples, stochastic subsampling of parameters and using a gradient based approach in combination with the classical trust region method. We found that stochastic subsampling methods can, in some cases, reduce the CPU time required to reach a reasonable solution when compared to the classical trust region method but this was not consistent across all datasets. We also found that using the classical trust region method in combination with mini-batch gradient descent either successfully matched (within 0.1s) or decreased the CPU time required to reach a reasonable solution for all datasets. This was achieved by only computing the trust region step when training progress using the gradient approach had stalled

A decade of change : the development of family centered care in a neonatal intensive care unit

University of Technology, Sydney. Faculty of Nursing, Midwifery and Health.This thesis is about change in nursing practice in a neonatal nursery. It examines the process of change as the development of a family centered care (FCC) philosophy and practices are integrated into the nursing care within the Neonatal Intensive Care Unit (NICU) over a ten-year period. This is a qualitative study that uses case study methodology to examine and analyse the context and processes involved in achieving change in neonatal nurseries. The data used for the case study included, reports and publications from previous research projects relating to the development of a FCC philosophy in the NICU, interviews and focus groups held in 2001-2002 and in 2004-2005. A staged thematic analysis and confirmation process was used for the analysis. The data analysis and themes developed from the data indicate there has been change in practice over time in the involvement of parents in the care of their infant in the NICU. There is evidence that many of the nurses have moved from an expert framework to a framework in which a two-sided conversation between nurses and parents should and often does occur. The change is not complete as it an ongoing and dynamic process and the nurses recognised further ongoing issues relating to control, 'ownership' and resistance to change. The diffusion of innovation theory provided an appropriate framework to think about a change in nursing practice over time. It provides a structured approach to describing change in practice with emphasis on communication networks. The roles of opinion leaders and change agents are integral to the diffusion process. The neonatal nurses who participated in the study identified other useful strategies that assist in the change process. They specifically identified the importance of ongoing education, including, less didactic methods of teaching and learning, such as role modelling, mentoring, feedback, reflection and discussion of relevant experiences; policies and procedures to support the change, engagement and participation of staff through group development processes and summaries of written research evidence. The change to a FCC philosophy and practices in the NICU is an ongoing journey that has taken considerable time. The rate of acceptance of FCC as an innovation in practice has been effected by a number of factors. These include, the readiness of the nursing staff to change, the attitudes and role perceptions of nurses and parents about their boundaries of care and responsibilities for the wellbeing of the infant, the lack of consistency and shared understandings in the clinical judgment and decision making process, and the nurses skills to engage and enable parents in parenting their child in a relatively foreign and 'hostile' environment such as the nursery. The implications for clinical practice include the recognition of the necessity for maintenance strategies to be developed in the NICU to ensure practice remains at the same level and does not slip back, a possible strategy could include clinical supervision or reflective practice groups. In addition, it is apparent that there is a need to continue to work towards integration of FCC philosophy and practices into the clinical practice of all nursing staff. The establishment of a working group of interested staff to continue the development of FCC philosophy and practices and to develop strategies to overcome any remaining barriers may be appropriate. Finally, education needs to continue covering topics such as Kangaroo Care (KC), FCC philosophy and practices, and communication skills