Based on cross-sectional data drawn from 135 treated and 68 control farmers in Tanzania, and 133 treated and 71 control farmers in Zambia, this study uses propensity score matching to test whether conservation agriculture (CA) improves smallholder farmers’ welfare, in response to the policy objective of enhancing their resilience in the face of climate change. Farmers in Tanzania assess CA as having statistically significant impacts on increasing total agricultural yield, adaptation to climate change impacts, resilience to droughts, increasing maize production, enhancing household food security, increasing number of meals per day, increasing household income, accumulation of productive assets , addressing gender disparity and social cohesion, and improving soil health . However, CA had no impact on reducing the forest area cleared per year and total agricultural costs. Farmers in Zambia assess CA as having statistically significant impacts on increasing total agricultural yield , adaptation to climate change impacts, resilience to droughts, increasing maize production, enhancing household food security, increasing number of meals per day, decreasing number of food insecure months, increasing household income, accumulation of productive assets, addressing agricultural calendar bottlenecks, increasing total agricultural costs, addressing gender disparity and social cohesion, and decreasing soil health. However, CA had no impact on reducing forest area cleared per year. Policy could use such evidence to leverage CA adoption in support of the sustainable development goals (SDGs) and Africa Agenda 2063, although its potential to sequester carbon and provide ecosystem services comes into question. / Dissertation (MSc Agric (Agricultural Economics))--University of Pretoria, 2021. / AERC-CMAAE / African Conversation Tillage Network / Agricultural Economics, Extension and Rural Development / MSc Agric (Agricultural Economics) / Unrestricted

Motor vehicle collisions (MVCs) are a leading cause of injuries and injury-related fatalities in the United States. The National Highway Traffic Safety Administration (NHTSA) reported over 21,250 vehicle occupant fatalities in 2011, with 1,240,000 injuries sustained by passenger car occupants alone. MVCs are a common cause of blunt abdominal injuries. It has been reported that approximately 9,000 front seat occupants sustain moderate to severe abdominal injuries in frontal MVCs in the United States each year. A detailed understanding of the occurrence and mechanisms of abdominal injuries, as well as knowledge of the biomechanical response and tolerance of the abdomen in crash-specific loading modes, could benefit the reduction of abdominal organ injury incidence in MVCs. Therefore, the objective of the research presented in this dissertation was to characterize abdominal injury mechanisms, tissue failure thresholds, and internal organ response to blunt impacts of the abdomen. Field accident data from the Crash Injury Research and Engineering Network (CIREN) database were analyzed to determine the occupant and crash characteristics associated with crash-induced hollow abdominal organ injuries. Dynamic equibiaxial tension tests were conducted on tissue samples obtained from the human post-mortem stomach, small intestine, and colon to characterize the material properties and failure tolerance of these tissues. The effects of cadaver orientation on the relative position of the abdominal organs of two cadavers were quantified, and high-speed biplane x-ray imaging was used to investigate the relative kinematics of the thoracic and abdominal organs of four cadavers in response to crash-specific loading modes. Test configurations included blunt abdominal and thoracic impacts and driver-shoulder seatbelt loading. The motivation for this research was to advance efforts toward abdominal organ injury mitigation in MVCs, with each aspect of this research generating novel injury biomechanics data with applications for future experimental testing and finite element modeling. / Ph. D.

This thesis contributes to the understanding of the most effective ways to promote sustainable and inclusive development. It uses public private partnerships in infrastructure projects as a case study for demonstrating that a holistic approach of development that incorporates human rights considerations is needed to achieve sustainable and inclusive development outcomes. The dissertation explores different notions of development and how they have influenced the regulatory frameworks for and the structuring of Infrastructure projects and their effectiveness in achieving their intended development outcomes. It demonstrates that public-private partnerships add several layers of complexity to infrastructure finance, planning and implementation, and that they can result in a significant gap between the project’s intended and actual developmental outcomes. The thesis proposes that governments and other project sponsors use human rights impact assessments (HRIAs) to address the challenges created by public-private partnerships in infrastructure projects and shows that this will help increase the possibility that infrastructure PPPs lead to sustainable development outcomes. The thesis also analyses a number of established human rights impact assessment methodologies and proposes a new approach that is specifically designed for the particular context of public-private partnerships in infrastructure projects. / Thesis (LLD)--University of Pretoria, 2020. / National Research Foundation (NRF) / Centre for Human Rights / LLD / Unrestricted

Impact evaluation (IE) has become a major focus of Extension program evaluation during the past three decades, yet Extension professionals continue to struggle to produce well-documented evidence of program impacts (Lamm, 2011; Workman, 2010). This research was primarily a quantitative, non-experimental correlational study of factors associated with Extension educators’ IE behaviors and practices in the North Central Region of the Cooperative Extension service. The study employed a comprehensive, systems approach to explore interrelated individual and organizational factors that affect IE in Extension. A major feature of this research design was the use Structural Equation Modeling (SEM) statistical analysis methodology. The use of SEM to organize and implement this study facilitated simultaneous exploration of many constructs theorized to be involved in IE behaviors in the context of Extension educational program evaluation. Specification of a theoretical, conceptual model to be used to frame the potential relationships among the many constructs and factors was necessary prior to data collection in order to be able to use SEM for data analysis. Data were analyzed using SEM path analysis to determine relationships among the factors. Significant findings included the identification of the most influential factors on the dependent variable of actual IE behaviors. These were: competency by perceived skill level, behavioral intention, number of roles in IE, education level, and attitude. Factors exhibiting noteworthy influence on factors other than the dependent variable within the model included training, culture, and proportion of teamwork. Qualitative data themes most frequently mentioned by participants included: the need to know how to measure change; a need for training in general; a need for better planning of programs to achieve impact; conflicting priorities, lack of time and timing/coordination concerns; changing expectations (“moving target”) regarding IE practices and goals; and diverseness in contexts, competencies, and schedules. Study findings identified a number of influential factors not previously cited in literature, including number of roles in IE; proportion of teamwork employed in IE; a lack of understanding of how to measure change; and issues of diverseness regarding competencies, context (including stakeholder expectations), and scheduling within the Extension organization.

This study focused on the search of the impact of absent father on the lives of young adults in the household. In the interview with the coparticipants, the research revealed that the problems of absent father prevailed and continued to traumatize young adults despite the execution of pastoral care of laying hands and uttering of prayers on young adults by pastors and deacons of the church since these are the pastoral practices and care the church offers to assist in halting the problems. The absence of pragmatic of pastoral method caused dismay more especially on young adults because they perceived a church as a family of God which is endowed with power to provide healing and comfort abundantly in their lives as well as changing the mind-set of their fathers who deserted them. Prior to this research the inability to deal and solve the problems of absent father caused the congregation to encounter dilemma because some members of the congregation emphasized that these young adults who their problems of absent father seem not to be solved by prayer and laying of hands must be referred to psychologist while others suggested that such young adults must be excommunicated because they disturb the smooth running of the worshipping in the church. These views prompted the current research. It was, therefore, the aim of this study to journey with the coparticipants in order to understand and have knowledge of the situation they are encountering so that the research will employ the appropriate pastoral care and practice to assist them to get rid of the problems of absent father, / Dissertation (MA)--University of Pretoria, 2015. / Practical Theology / MA / Unrestricted

The main objective of the thesis is an analysis of possible future scenarios. This research is systematically focused on the analysis of the future possible trends in the context of the Slovak Republic's environment. The basis of the analysis is to identify the key external drivers and according to them to create the final scenarios of the future. The main approach to the scenario building in this thesis is the method of Cross-Impact Balance. Scenarios were created by semi-structured interviews with experts and by using the combinatorial analysis of consistency in terms of cross-impact of individual variants of the driving forces. The result of this thesis is five scenarios, referring to the future context of the environment of the Slovak Republic, depending on the development of a combination of different variants of external factors. For this scenarios there has been prepared the analysis of risks and opportunities in the perspective of the Environment of the Slovak Republic. Identified scenarios can be briefly described through the impact from least to the most positive. The first scenario shows the threat of an environmental collapse. The second scenario describes a power struggle over the resources and the consequences of excessive use of raw materials. The middle scenario describes the risk...

ABSTRACT A Study on the Violent Interactions of an Immiscible Drop Impacting on a Superheated Pool Mohamad Alchalabi The interactions between two immiscible liquids of different temperatures can be violent to the extent of causing harm to individuals, or damage to equipment, especially when used in the industry. Only a few studies investigated these interactions but they could not produce the violent interactions often reported by the industry, and therefore their results did not help much to develop clear understanding of the dynamics of these interactions. In this work, a high speed imaging system operated at 100,000 frames per second was utilized to record the events and phenomena taking place upon the impact of Perfluorohexane droplet at room temperature onto a hot soybean oil pool at temperatures as high as 300 ºC. The impact velocity was varied by varying the height of the droplet before it pinches off under its own weight. The recorded events identified the occurrence of vortex ring vapor explosions, weak and strong nucleate boiling, and film boiling. An impact velocity vs. oil temperature diagram identifying the regions in which each of these phenomena takes place was generated, and the dynamics driving their occurrences were explored. The vortex ring vapor explosions were found to become less violent as the impact velocity was increased, which was attributed to the existence of a smaller amount of liquid Perfluorohexane within the rings at high speed impacts, which does evaporate but does not expand violently. Weak nucleate boiling occurred at very high impact velocities relatively. As the temperature is increased, however, they start 5 turning into strong nucleate boiling. The strong nucleate boiling usually starts right upon impact, and when the temperature of the oil at one impact velocity is increased, it starts turning into film boiling, in which the liquid Perfluorohexane is covered by a vapor layer of its own vapor.

Fibre reinforced polymers (FRP) are finding increasing use in structures subjected to high rate loading such as blast or impact. Proper design of such structures requires thorough characterisation of the material behaviour over a range of loading rates from quasi-static to impact. This thesis investigated the quasi-static and impact response of Glass Fibre Polypropylene (GFPP) in compression, bending and delamination. The bending and delamination response of Fibre Metal Laminates (FMLs) based on GFPP and aluminium was also investigated at quasi-static and impact rates. High strain rate (5x10^2 to 10^3 /s) compression tests were conducted on GFPP using a compressive Split Hopkinson Pressure Bar (SHPB) and a Direct Impact Hopkinson Pressure Bar (DIHPB), in the through-thickness and in-plane directions. In both loading directions, the peak stress of GFPP increased linearly with the logarithm of strain rate. For in-plane loading, the failure modes were dominated by localised fibre buckling and kink bands, leading to delamination. The through thickness loading produced macroscopic shear and spreading failure modes. However, both of these failure modes are linked to in-ply fibre failures, due to through thickness compression causing transverse tensile strain. Previous studies of similar materials have not explicitly stated the link between through thickness compression and fibre failure associated with transverse tensile strain. A novel test rig was developed for Three Point bend testing at impact rates. The specimen was supported at the outer points on a rigid impacter and accelerated towards a single output Hopkinson Pressure Bar (HPB), which impacted the specimen at its midspan. Previous impact bend test rigs based on HPBs were limited to testing specimens with deflections to failure up to approximately 1mm, whereas the rig implemented herein measured deflections up to approximately 10 mm. This configuration permits the output HPB to be chosen purely on the magnitude of the expected impact force, which resulted in superior force resolution to configurations used in other studies. The HPB Impact Bend rig was used to test GFPP and aluminium-GFPP FML specimens, at impact velocities ranging from 5 to 12 m/s. The flexural strength of GFPP increased with strain rate, while the flexural response of the FML specimens was relatively insensitive to strain rate. v Several candidate delamination test geometries were investigated at quasi-static displacement rates (1 mm/min), and the Single Leg Bend (SLB) test was identified as suitable for adaptation to higher rate testing. Single Leg Bend delamination tests of both GFPP and FML specimens were performed using the HPB Impact Bend rig, at impact velocities of 6 to 8 m=s. The shape of the force displacement response for the high rate testswas markedly different from the quasi-static tests, for both the GFPP and FML specimens. Finite element (FE) simulation of the quasi-static and impact rate SLB tests on GFPP indicated that the difference was probably due to the interaction of flexural vibrations and stress waves in the specimen and the impacter cross member. The experimental results and FE analysis suggest that the delamination fracture toughness of GFPP decreases slightly as strain rate increases. High rate delamination tests on FML specimens resulted in unstable crack growth.

Despite the emergence of artificial intelligence (AI) and machine learning (ML) in medicine and the resultant interest in predictive analytics in surgery, there remains a paucity of research on the actual impact of prediction models and their effect on surgeons’ risk assessment of post-surgical complications. This research evaluated how spinal surgeons predict post-surgical complications with and without additional information generated by a ML predictive model. The study was conducted in two stages. In the preliminary stage an ML prediction model for post-surgical complications in spine surgery was developed. In the second stage, a survey instrument was developed, using patient vignettes, to determine how providing ML model support affected surgeons’ predictions of post-surgical complications. Results show that support provided by a ML prediction model improved surgeons’ accuracy to correctly predict the presence or absence of a complication in patients undergoing spinal surgery from 49.1% to 54.8% (p=0.024). It is clear that predicting post-surgical complications in patients undergoing spinal surgery is difficult, for models and experienced surgeons, but it is not surprising that additional information provided by the ML model prediction was beneficial overall. This is the first study in the spine surgery literature that has evaluated the impact of a ML prediction model on surgeon prediction accuracy of post-surgical complications.

No description available.