Sensitivity Analysis of Basins of Attraction for Gradient-Based Optimization Methods

This project is an analysis of the effectiveness of five distinct optimization methods in their ability in producing clear images of the basins of attraction, which is the set of initial points that approach the same minimum for a given function. Basin images are similar to contour plots, except that they depict the distinct regions of points--in unique colors--that approach the same minimum. Though distinct in goal, contour plots are useful to basin research in that idealized basin images can be inferred from the steepness levels and location of extrema they depict. Effectiveness of the method changes slightly depending on the function, but is generally defined as how closely the basin image models contour information on where the true minima are located, and by the clarity of the resulting image in depicting well-defined regions. The methods are tested on four distinct functions which were chosen to assess how each method performs in the presence of various challenges. This project ranks the five methods for their overall effectiveness and consistency across the four functions, and also analyzes the sensitivity of the methods when small changes are made to the function. In general, less sensitive and consistently effective methods are more applicable and reliable in applied optimization research

A Cognitive Structural Approach To Uncertainty Orientation In Terms Of Individual Differences In Construct Accessibility

This dissertation examined the view that certainty- and uncertainty-oriented individuals are individuals for whom certainty and uncertainty, respectively, are cognitively relevant (Sorrentino, Short, & Raynor, in press). Study 1 examined whether certainty-related behavioral descriptions about another were better remembered by certainty-oriented subjects than uncertainty-oriented subjects, as a construct accessibility model of differences in the relative accessibility of certainty- and uncertainty-related constructs would predict (e.g., Higgins & King, 1981). Distortions of evaluatively ambiguous and evaluatively unambiguous descriptions were also examined. The data supported a cognitive structural view of individual differences in uncertainty orientation in terms of knowledge structures based on past experience (or schemata) which contain both certainty- and uncertainty-related information that is both differentially accessible and differentially evaluated by certainty- and uncertainty-oriented individuals. For example, uncertainty-oriented subjects are seen as having knowledge structures composed of a large amount of positively-tagged, uncertainty-related information and a smaller amount of certainty-related information that is negatively-tagged or viewed in a negative manner. A bipolar model of schemata in the uncertainty-certainty domain therefore was proposed to account for the results of Study 1.;A second study examined the relative utility of two cognitive structural views of differences in uncertainty orientation: one in terms of differences in integrative complexity (Schroder, Driver, & Streufert, 1967) and the other in terms of differences in self-schemata (Markus, 1977). Compared to low need for uncertainty individuals, high scorers in need for uncertainty tended to have more highly differentiated cognitive structures and to display better overall memory for information about another. Uncertainty-oriented individuals had better relative memory than certainty-oriented individuals for accessible versus inaccessible behavioral descriptions about another over time, but the reverse was found on an immediate recall measure. A general processing model incorporating both the integrative complexity and self-schemata approaches was proposed to account for the observed relations between uncertainty orientation, need for uncertainty, degree of cognitive structure in the interpersonal domain, and the processing of interpersonal information. In summary, both studies supported a cognitive structural view of differences in uncertainty orientation and revealed that this variable has important effects on the processing and remembrance of information about others

Exploring the Potential of Social Media Platforms as Data Collection Methods for Accessing and Understanding Experiences of Youth with Disabilities: A Narrative Review

Purpose: Social media (SM) is a critical component of youth culture, and may provide a useful platform for exploring young people’s authentic voices. This narrative review considers how researchers are exploring the experiences of youth with disabilities using SM.  Methods: Five health and social science databases were searched using terms related to ‘social media’ and ‘data collection’. Articles were reviewed for relevancy. Narrative analysis was undertaken.Results: Searches returned 1524 results, of which 15 articles were included. SM-based data collection methods fell into three categories: 1) observational; 2) interactive; and 3) combined online/offline, each offering unique advantages to data collection. Literature suggests that SM can be used to effectively explore self-care, coping and social experiences of youth with health conditions, however youth with disabilities were notably absent from all three categories.Conclusion: As a prominent component of youth culture, researchers have turned to SM-based data collection methods to understand youths’ real-world experiences. It is imperative, however, that the voices of youth with varied abilities and backgrounds be included in the conversation.

Effect of alcohol addition on the movement of petroleum hydrocarbon fuels in soil

Groundwater contamination by fuel spills from aboveground and underground storage tanks has been of growing concern in recent years. This problem has been magnified by the addition of oxygenates, such as ethanol and methyl-tertiary-butyl ether (MTBE) to fuels to reduce vehicular emissions to the atmosphere. These additives, although beneficial in reducing atmospheric pollution, may, however, increase groundwater contamination due to the co-solvency of petroleum hydrocarbons and by the provision of a preferential substrate for microbial utilisation. With the introduction of ethanol to diesel fuel imminent and the move away from MTBE use in many states of the USA, the environmental implications associated with ethanol additive fuels must be thoroughly investigated. Diesel fuel movement was followed in a 1-m soil column and the effect of ethanol addition to diesel fuel on this movement determined. The addition of 51% ethanol to diesel fuel was found to enhance the downward migration of the diesel fuel components, thus increasing the risk of groundwater contamination. A novel method using soil packcd HPLC columns allowed the influence of ethanol on individual aromatic hydrocarbon movement to be studied. The levels of ethanol addition investigated were at the current additive level (approx. 25%) for ethanol additive fuels in Brazil and values above (50%) and below (10%) this level. An aqueous ethanol concentration above 10% was required for any movement to occur. At 25% aqueous ethanol, the majority of hydrocarbons were mobilised and the retention behaviour of the soil column lessened. At 50% aqueous ethanol, all the hydrocarbons were found to move unimpeded through the columns. The retention behaviour of the soil was found to change significantly when both organic matter content and silt/clay content was reduced. Unexpectedly, sandy soil with low organic matter and low silt/clay was found to have a retentive behaviour similar to sandy subsoil with moderate silt/clay, but little organic matter. It was concluded that sand grains might have a more important role in the adsorption of petroleum hydrocarbons than first realised. This method has shown that soil packed HPLC columns can be used to provide a quick estimate of petroleum hydrocarbon, and possibly other organic contaminant, movement in a variety of different soil types

Assembling activity/setting participation with disabled young people

Rehabilitation research investigating activity participation has been largely conducted in a realist tradition that under-theorises the relationship between persons, technologies, and socio-material places. In this Canadian study we used a post-critical approach to explore activity/setting participation with 19 young people aged 14 to 23 years with complex communication and/or mobility impairments. Methods included integrated photo-elicitation, interviews, and participant observations of community-based activities. We present our results using the conceptual lens of assemblages to surface how different combinations of bodies, social meanings, and technologies enabled or constrained particular activities. Assemblages were analysed in terms of how they organised what was possible and practical for participants and their families in different contexts. The results illuminate how young people negotiated activity needs and desires in particular ‘spacings’ each with its own material, temporal, and social constraints and affordances. The focus on assemblages provides a dynamic analysis of how dis/abilities are enacted in and across geotemporal spaces, and avoids a reductive focus on evaluating the accessibility of static environmental features. In doing so the study reveals possible ‘lines of flight’ for healthcare, rehabilitation, and social care practices

School Roles: A Way to Investigate Participation

Students who are more engaged in school have higher academic achievement, lower dropout rates, and increased involvement in activities during early adult-hood. Unfortunately, children with disabilities participate less than children without disabilities, thus increasing their risk for depression and anxiety. This study investigated the lack of school participation from a roles perspective. Roles refer to clusters of meaningful activities that are expected of, and assumed by, in-dividuals in various contexts of their lives. Fifteen teachers from Southern Ontario, Canada, were interviewed about the roles in which children participate in school and 24 students in grades 4 through 7 were observed in order to deter-mine the roles in which they engaged. Overall, students with disabilities engaged in less positive roles (Challenged Learner; Victim; Bully), while students without disabilities engaged in more positive roles (Independent Learner; Nurturer; Friend). Ideas for improving participation through role identity and engagement are discussed

Load transfer at the distal ulna following simulated distal radius fracture malalignment.

PURPOSE: To measure the effects of distal radius malalignment on loading at the distal ulna. METHODS: Using an adjustable mechanism to simulate angulated and translated malalignments, clinically relevant distal radius deformities were simulated in a cadaveric model. A custom-built load cell was inserted just proximal to the native ulna head to measure the resultant force and torque in the distal ulna. Loads were measured before and after transecting the triangular fibrocartilage complex (TFCC). RESULTS: There was an increase in distal ulna load and torque with increasing dorsal translation and angulation. Combined conditions of angulation and translation increased force and torque in the distal ulna to a greater extent than with either condition in isolation. Transecting the TFCC resulted in a reduction in distal ulna load and torque. CONCLUSIONS: A progressive increase in load at the distal ulna was observed with increasing severity of malalignment, which may be an important contributor to residual ulnar wrist pain and dysfunction. However, no clear-cut threshold of malalignment of a dorsally angulated and translated distal radius fracture was identified. These observations suggest that radius deformities cause articular incongruity, which increases TFCC tension and distal radioulnar joint load. Cutting of the TFCC decreased distal ulna loading, likely by releasing the articular constraining effect of the TFCC on the distal radioulnar joint, allowing the radius to rotate more freely with respect to the ulna. CLINICAL RELEVANCE: Anatomical reduction of a distal radius fracture minimizes the forces in the distal ulna and may reduce residual ulnar wrist pain and dysfunction

An integrated methods study of the experiences of youth with severe disabilities in leisure activity settings: The importance of belonging, fun, and control and choice

Purpose: The aim was to examine the leisure activity setting experiences of two groups of youth with severe disabilities-those with complex continuing care (CCC) needs and those who have little functional speech and communicate using augmentative and alternative communication (AAC). Method: Twelve youth took part in a mixed methods study, in which their experiences were ascertained using qualitative methods (observations, photo elicitation and interviews) and the measure of Self-Reported Experiences of Activity Settings (SEAS). Data integration occurred using a following a thread technique and case-by-case analysis. Results: The analysis revealed several highly valued aspects of leisure activity setting experiences for youth, including engagement with others, enjoying the moment, and control and choice in selection and participation in activity settings. Conclusions: The findings provide preliminary insights into the nature of optimal activity settings for youth with severe disabilities, and the mediators of these experiences. Compared to other youth, the data illustrate both the commonalities of experiences and differences in the ways in which these experiences are attained. Implications for research concern the utility of mixed methods approaches in understanding the complex nature of participation experiences. Implications for clinical practice concern the importance of not assuming the nature of youths\u27 experiences.Implications for RehabilitationService providers can lose sight of the importance of broader concepts of belonging, fun, and control and choice when providing interventions that focus on participating in an activity to build specific skills.In addition to the skill-based outcomes for youth with disabilities that are valued by the rehabilitation system, we suggest that consideration needs to be given to other types of outcomes that matter to youth, such as participating in a leisure activity for the sake of belonging or having fun.It is important not to assume that youth with severe disabilities are not enjoying their participation or are not benefiting from their leisure experiences.It is important not to over-therapize youth with disabilities and promote a balanced approach to therapy and leisure participation, by discussing with youth and families the beneficial developmental outcomes that can accrue from leisure activities

A Qualitative Study of Workplace Factors Influencing Expertise in the Delivery of Children’s Education and Mental Health Services

Background: Interest in professional expertise is growing. Interactional and developmental perspectives are being adopted to understand the nature of expertise and the environmental factors that influence its development. This article provides qualitative information about the workplace factors and experiences considered important by individuals providing education or mental health services to children, with one group working within an interprofessional team approach (service providers) and the other working in a discipline-specific manner (teachers).Methods and Findings: Two focus groups were held: one involving 5 elementary or secondary school teachers and principals, and one involving 9 therapists who provide specialized children’s mental health services. Information arising in these group sessions was used to develop themes reflecting key elements discussed; the themes were then contrasted to infer differences between the two groups. The findings point to the importance of establishing a collaborative, learning-oriented workplace culture, including opportunities for varied work experiences, peer interaction and dialogue, and feedback.Conclusions: Implications include adopting relationship-oriented and collaborative service delivery models and ensuring that workplace settings encourage natural learning opportunities involving interaction, dialogue, and feedback, as well as meaningful professional development experiences of value to participants

An investigation into the sample preparation procedure and analysis of cyanoacrylate adhesives using capillary electrophoresis

In this study, the trace acid profile of cyanoacrylate adhesives was studied using capillary electrophoresis. Liquid–liquid extraction was employed as the sample preparation step before separation by capillary electrophoresis. The solubility of the adhesives was investigated using various organic solvents, e.g. hexane and dichloromethane, and chloroform was determined to be the optimum solvent as it enabled the full dissolution of the adhesive. A comprehensive stability study was performed over a 3-year period and results indicate that the adhesives were stable for 2 years after which their stability and performance degraded