It is known that a phase-perturbed object field from a fractal-like rough surface illuminated by a partially coherent beam generates speckle on the image plane. In this works, aberration effects on Gaussian speckle on the image plane in both perfectly and partially coherent systems are theoretically and experimentally investigated. Theory shows that the second order statistics of Gaussian laser speckle are independent of odd-functional aberrations, but they do affect Gaussian speckle contrast in a partially coherent system. Furthermore, it is theoretically derived that field statistics of Gaussian laser speckle generally become non-circular Gaussian due to aberrations, and an aberration effect is asymptotically ignorable for very weak or strong roughness. A brute force simulation method is introduced for non-Gaussian speckle in a partially coherent imaging system, where speckle irradiance is calculated from a quasi-monochromatic extended incoherent source. The source is modeled as a collection of independent point sources distributed on a regular grid. The partially coherent speckle pattern is calculated from the incoherent sum of coherent speckle patterns in the image plane generated from each point source. Speckle contrasts from a brute force model show good agreement with theoretical and experimental results. It is determined that non-Gaussian speckle contrast is strongly dependent on Hurst exponent of fractal rough surfaces using brute force simulations. The concept of a contributing object area at a fixed image point effectively explains the speckle contrast dependency. Measuring spherical aberrations using Gaussian laser speckle is discussed as one of applications and future works of the present study.

Not much research regarding burnout amongst clergy in South Africa has been done. Recently a shift in the direction of positive psychology or salutogenesis took place and which highlighted two relatively new constructs, namely sense of coherence and engagement. Previous research in the "Nederduitse Gereformeerde Kerk" (NG Church) found a correlation between sense of coherence and burnout. In the "Nederduitsch Hervormde Kerk van Afrika" (NH Church) however, no research regarding burnout within a salutogenic paradigm was ever done. The general objective of this research was to determine the levels and relationship of sense of coherence, coping, burnout and engagement amongst ministers of the NH Church. A cross-sectional research design was used. The Orientation to Life Questionnaire (OLQ), COPE-Questionnaire (COPE), Maslach Burnout Inventory-Human Services Survey (MBI-HSS) and the Utrecht Work Engagement Scale (UWES) were used as measuring instruments on a stratified random (proportional) sample (n = 200) of ministers of the NH Church and from which 87 useable responses were received. Structural equation modelling was applied on the MBI-HSS to confirm a three-factor model with best fit. Cronbach alpha coefficients, inter-item correlation coefficients and factor analysis were used to determine the reliability and validity of the measuring instruments. Descriptive statistics, Pearson-product correlation coefficients, canonical correlation coefficients, and analysis of variance were used to analyse the data. The results showed that high levels of sense of coherence, approach coping and high levels of engagement are related to low levels of burnout, while venting of emotions are related to high levels of burnout. It was also found that sense of coherence and coping predicted emotional exhaustion, depersonalisation and personal accomplishment. Furthermore, it was found that levels of emotional exhaustion for ministers in the age group 25-29, were consistently lower than that of any other age group in the sample, while levels for the age group 50-65 were also lower than that for ministers in the age groups 30-39 and 40-49, but still higher than levels for age group 25-29. Limitations of the study and recommendations regarding the organisation and future research were indicated. / Thesis (MA (Industrial Psychology))--North-West University, Potchefstroom Campus, 2004.

Companies, also financial institutions, realign, redesign, restructure and downsize on an ongoing basis, increasing tension in employees to survive in the work environment. Besides coping with the impact of recessions and layoffs, employees also have to cope with increased workloads and the pressures of modem life. Employment is not only a means of financial viability, but also defines individuals' identities. Job loss - or even the threat of it - can be psychologically devastating and may influence the psychological well-being of employees. This may impact their perceived job satisfaction as well. The current trend within organisations is to move towards a model that focuses on strengths, where individuals take charge of their own lives and have effective working conditions where they successfully cope and perform optimally. The objective of this research was to determine the relationship between psychological wellbeing (i.e. self-efficacy, positive and negative affect, and sense of coherence) and job satisfaction of employees in a financial institution. The research method for this article consisted of a brief literature review and an empirical study using a cross-sectional survey design to collect data. An availability sample (N = 117) was taken from employees from different levels in a financial institution. The Minnesota Satisfaction Questionnaire (MSQ), Generalised Self-Efficacy Scale (GSES), Affectometer 2 (AFM), Orientation to Life Questionnaire (OLQ) and a Biographical questionnaire were administered. The statistical analysis was carried out with the help of the SPSS-programme. The statistical methods utilised in the article consisted of descriptive statistics, Cronbach alpha coefficients, Pearson product-moment correlation coefficients, Regression analysis and Manovas. The results showed acceptable internal consistencies for all the constructs. Product-moment correlation coefficients showed significant positive correlations between self-efficacy, positive affect, sense of coherence and job satisfaction and significantly negative correlations between negative affect, self-efficacy, positive affect and sense of coherence. Self-efficacy, positive and negative affect, and sense of coherence predicted 19% of the variance in job satisfaction with sense of coherence the only significant predictor of Job Satisfaction. No differences in terms of biographical characteristics in the experience of self-efficacy, positive affect, negative affect, sense of coherence and job satisfaction could be found. Recommendations for future research were made. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2006.

No description available.

Optical coherence tomography (OCT) has been shown to be a versatile three-dimensional imaging tool in diagnostic medicine, combining micrometre-scale resolutions with fast acquisition times. This imaging modality uses the interference between light backscattered from a sample and light that has traversed a known reference path delay to determine the scattering profile over penetration depths of up to several millimetres in tissue. A novel OCT system is presented that uses nonlinear optics to process the backscattered light in the optical domain prior to standard Fourier-domain OCT acquisition and processing. The nonlinear optical effects experienced between short light pulses are strongly intensity-dependent, occurring only significantly when the pulses are temporally and spatially overlapped. These conditions allow for the creation of a user-controlled time gate that restricts the light backscattered from the sample to a narrow (~100 micrometres) depth field of view prior to detection. When strong and weak scattering interfaces exist across the sample depth range, the signal-to-noise ratio of the weaker scattering sites can be limited by the finite detector dynamic range in Fourier-domain OCT systems. By aligning the time gate temporal delay to the backscatter from the weak interfaces of interest, a user can completely remove the strong backscattered light and enhance imaging contrast. The nonlinear effect used in the current time-gated OCT design is sum-frequency generation, which provides an additional advantage of imaging at near infrared (1280 nm) wavelengths, used for long penetration depths in tissue, while detection is performed in the visible (504 nm) with silicon-based camera technology. With the reduced depth field of view, the number of sampling points required per depth scan is also proportionately reduced, permitting faster acquisition rates for the time-gated region of interest. A complete description of the time-gated OCT system design is presented, along with proof-of-concept images demonstrating contrast enhancement and operation in a highly scattering biological medium. Based on its successful initial performance, future development of this system is expected for its eventual use in many OCT imaging applications. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2008-01-15 20:05:41.665 / This work was funded by the Natural Sciences and Engineering Research Council and the Cancer Imaging Network of Ontario, supported by Cancer Care Ontario

The pathophysiology of essential tremor (ET) is not clearly understood but is thought to involve multiple brain regions. The purpose of this study was to describe in greater detail head tremor in ET and to investigate the possible relationship between head and hand tremor. Ten ET subjects were recruited (1 male, 9 female) and compared to three control subjects (1 male, 2 female). Head and hand tremors were recorded simultaneously with surface electromyography (EMG) of the wrist extensors and various neck muscles, laser displacement sensors (hand tremor), a load cell (hand tremor) and an accelerometer (head tremor). While seated, subjects performed four tasks: 1) constant force (10% maximum) wrist extensions (with and without visual feedback); maintenance of the hands in a horizontal posture against gravity while 2) seated upright in a chair, 3) seated in a reclined chair (20° backward, head not supported); and 4) seated upright in a chair and producing steady submaximal hip adduction forces. Head tremor spectral peaks were found between 3.5 and 7 Hz in neck muscle EMG and the accelerometer signal. Wrist tremor (EMG and kinematic data) was slightly higher in frequency with a range of 4 -10 Hz. Of the ten ET subjects recruited for this study, 60% (n = 6) demonstrated significant levels of coherence (p < 0.05) in at least one neck-wrist muscle comparison at the fundamental frequency of their tremor. The results demonstrated an obvious bias of the trapezius descendens (TD) muscles over the more axial neck muscles to demonstrate significant coherence with the extensor carpi radialis (ECR) muscles. Of the six neck muscles investigated, the SPLs and the SCMs were commonly driven at the same frequencies (change in frequency < 0.5), although this seldom resulted in coherence. There is indication that the oscillatory activity driving more distal muscles is different from that in the SPL and the SCM. Due to the multifunctional nature of the TD, it may be the recipient of two descending neural commands. These commands may each be of a different oscillatory frequency originating from different central oscillators. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2008-10-29 10:03:22.354

Optical Coherence Tomography (OCT) is a sub-surface imaging modality with growing number of applications. An accurate and practical OCT simulator could be an important tool to understand the physics underlying OCT and to design OCT systems with improved performance. All available OCT simulators are restricted to imaging planar multilayered media or non-planar multilayered media. In this work I developed a novel Monte Carlo based simulator of OCT imaging for turbid media with arbitrary spatial distributions. This simulator allows computation of both Class I diffusive reflectance, due to ballistic and quasi-ballistic scattered photons, and Class II diffusive reflectance due to multiple scattered photons. A tetrahedron-based mesh is used to model any arbitrary-shaped medium to be simulated. I have also implemented a known importance sampling method to significantly reduce computational time of simulations by up to two orders of magnitude. The simulator is verified by comparing its results to results from previously validated OCT simulators for multilayered media. I present sample simulation results for OCT imaging of non-layered media which would not have been possible with earlier simulators.

Not much research regarding burnout amongst clergy in South Africa has been done. Recently a shift in the direction of positive psychology or salutogenesis took place and which highlighted two relatively new constructs, namely sense of coherence and engagement. Previous research in the "Nederduitse Gereformeerde Kerk" (NG Church) found a correlation between sense of coherence and burnout. In the "Nederduitsch Hervormde Kerk van Afrika" (NH Church) however, no research regarding burnout within a salutogenic paradigm was ever done. The general objective of this research was to determine the levels and relationship of sense of coherence, coping, burnout and engagement amongst ministers of the NH Church. A cross-sectional research design was used. The Orientation to Life Questionnaire (OLQ), COPE-Questionnaire (COPE), Maslach Burnout Inventory-Human Services Survey (MBI-HSS) and the Utrecht Work Engagement Scale (UWES) were used as measuring instruments on a stratified random (proportional) sample (n = 200) of ministers of the NH Church and from which 87 useable responses were received. Structural equation modelling was applied on the MBI-HSS to confirm a three-factor model with best fit. Cronbach alpha coefficients, inter-item correlation coefficients and factor analysis were used to determine the reliability and validity of the measuring instruments. Descriptive statistics, Pearson-product correlation coefficients, canonical correlation coefficients, and analysis of variance were used to analyse the data. The results showed that high levels of sense of coherence, approach coping and high levels of engagement are related to low levels of burnout, while venting of emotions are related to high levels of burnout. It was also found that sense of coherence and coping predicted emotional exhaustion, depersonalisation and personal accomplishment. Furthermore, it was found that levels of emotional exhaustion for ministers in the age group 25-29, were consistently lower than that of any other age group in the sample, while levels for the age group 50-65 were also lower than that for ministers in the age groups 30-39 and 40-49, but still higher than levels for age group 25-29. Limitations of the study and recommendations regarding the organisation and future research were indicated. / Thesis (MA (Industrial Psychology))--North-West University, Potchefstroom Campus, 2004.

Companies, also financial institutions, realign, redesign, restructure and downsize on an ongoing basis, increasing tension in employees to survive in the work environment. Besides coping with the impact of recessions and layoffs, employees also have to cope with increased workloads and the pressures of modem life. Employment is not only a means of financial viability, but also defines individuals' identities. Job loss - or even the threat of it - can be psychologically devastating and may influence the psychological well-being of employees. This may impact their perceived job satisfaction as well. The current trend within organisations is to move towards a model that focuses on strengths, where individuals take charge of their own lives and have effective working conditions where they successfully cope and perform optimally. The objective of this research was to determine the relationship between psychological wellbeing (i.e. self-efficacy, positive and negative affect, and sense of coherence) and job satisfaction of employees in a financial institution. The research method for this article consisted of a brief literature review and an empirical study using a cross-sectional survey design to collect data. An availability sample (N = 117) was taken from employees from different levels in a financial institution. The Minnesota Satisfaction Questionnaire (MSQ), Generalised Self-Efficacy Scale (GSES), Affectometer 2 (AFM), Orientation to Life Questionnaire (OLQ) and a Biographical questionnaire were administered. The statistical analysis was carried out with the help of the SPSS-programme. The statistical methods utilised in the article consisted of descriptive statistics, Cronbach alpha coefficients, Pearson product-moment correlation coefficients, Regression analysis and Manovas. The results showed acceptable internal consistencies for all the constructs. Product-moment correlation coefficients showed significant positive correlations between self-efficacy, positive affect, sense of coherence and job satisfaction and significantly negative correlations between negative affect, self-efficacy, positive affect and sense of coherence. Self-efficacy, positive and negative affect, and sense of coherence predicted 19% of the variance in job satisfaction with sense of coherence the only significant predictor of Job Satisfaction. No differences in terms of biographical characteristics in the experience of self-efficacy, positive affect, negative affect, sense of coherence and job satisfaction could be found. Recommendations for future research were made. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2006.

The purpose of this study was to investigate the relationship between emotional intelligence, sense of coherence and coping behaviour in a group of students at a South African university. An availability sample of 101 students completed self-report measures of emotional intelligence, sense of coherence and coping behaviour. The measures were found to be valid and reliable in this particular group and the means and standard deviations calculated were comparable with those mentioned in literature. It was further found that emotional intelligence was better able, than sense of coherence, to predict the following coping strategies: turning to religion, suppression of competing activities, planning, active coping and problem solving. Emotional intelligence and sense of coherence were both good predictors of the coping strategy positive reinterpretation and growth. It was concluded that individuals with a high emotional intelligence have developed more effective coping strategies than individuals who do not have well-developed emotional abilities. Practical implications of the findings are indicated. / Thesis (M.A. (Psychology))--North-West University, Vaal Triangle Campus, 2005.