Measurement of the quality and performance of soft contact lenses is not new and is continually evolving as manufacturing methods develop and more complicated contact lenses become available. Qualification of soft contact lenses has not been a simple task since they are fundamentally difficult to measure. The shape of the lens is extremely sensitive to how the lens is supported and the material properties can change quickly with time. These lenses have been measured in several different ways, the most successful being non-contact optical methods that measure the lens while it is immersed in saline solution. All of these tests measure the lens in transmission and do not directly measure the surface structure of the lens. The reason for this is that the Fresnel reflectivity of the surface of a contact lens in saline solution is about 0.07%. Surface measurements have been performed in air, but not in saline. The lens needs to be measured in solution so that it can maintain its true shape. An interferometer is proposed, constructed, verified, and demonstrated to measure the aspheric low reflectivity surfaces of a contact lens while they are immersed in saline solution. The problem is extremely difficult and requires delicate balance between stray light mitigation, color correction, and polarization management. The resulting system implements reverse raytracing algorithms to correct for retrace errors so that highly aspheric, toric, and distorted contact lens surfaces can be measured. The interferometer is capable of measuring both surfaces from the same side of the contact lens as well as the lens thickness. These measurements along with the index of refraction of the lens material are enough build a complete 3D model of the lens. A simulated transmission test of the 3D model has been shown to match the real transmission test of the same lens to within 32nm RMS or 1/20th of a wave at the test wavelength.

This study investigates three high resolution optical imaging modalities to better detect and diagnose skin cancer. The ideal high resolution optical imaging system can visualize pre-malignant tissue growth non-invasively with resolution comparable to histology. I examined 3 modalities which approached this goal. The first method examined was high magnification microscopy of thin stained tissue sections, together with a statistical analysis of nuclear chromatin patterns termed Karyometry. This method has subcellular resolution, but it necessitates taking a biopsy at the desired tissue site and imaging the tissue ex-vivo. My part of this study was to develop an automated nuclear segmentation algorithm to segment cell nuclei in skin histology images for karyometric analysis. The results of this algorithm were compared to hand segmented cell nuclei in the same images, and it was concluded that the automated segmentations can be used for karyometric analysis.The second optical imaging modality I investigated was Optical Coherence Tomography (OCT). OCT is analogous to ultrasound, in which sound waves are delivered into the body and the echo time and reflected signal magnitude are measured. Due to the fast speed of light and detector temporal integration times, low coherence interferometry is needed to gate the backscattered light. OCT acquires cross sectional images, and has an axial resolution of 1-15 µm (depending on the source bandwidth) and a lateral resolution of 10-20 µm (depending on the sample arm optics). While it is not capable of achieving subcellular resolution, it is a non-invasive imaging modality. OCT was used in this study to evaluate skin along a continuum from normal to sun damaged to precancer. I developed algorithms to detect statistically significant differences between images of sun protected and sun damaged skin, as well as between undiseased and precancerous skin.An Optical Coherence Microscopy (OCM) endoscope was developed in the third portion of this study. OCM is a high resolution en-face imaging modality. It is a hybrid system that combines the principles of confocal microscopy with coherence gating to provide an increased imaging depth. It can also be described as an OCT system with a high NA objective. Similar to OCT, the axial resolution is determined by the source center wavelength and bandwidth. The NA of the sample arm optics determines the lateral resolution, usually on the order of 1-5 µm. My effort on this system was to develop a handheld endoscope. To my knowledge, an OCM endoscope has not been developed prior to this work. An image of skin was taken as a proof of concept. This rigid handheld OCM endoscope will be useful for applications ranging from minimally invasive surgical imaging to non-invasively assessing dysplasia and sun damage in skin.

More and more researchers and clinicians are looking to molecular sensing to predict how cells will behave, seeking the answers to questions like "will these tumor cells become malignant?" or "how will these cells respond to chemotherapy?" Optical methods are attractive for answering these questions because optical radiation is safer and less expensive than alternative methods, such as CT which uses X-ray radiation, PET/SPECT which use gamma radiation, or MRI which is expensive and only available in a hospital setting. In this dissertation, three distinct optical methods are explored to detect at the molecular level: optical coherence tomography (OCT), laser-induced fluorescence (LIF), and optical polarimetry. OCT has the capability to simultaneously capture anatomical information as well as molecular information using targeted contrast agents such as gold nanoshells. LIF is less useful for capturing anatomical information, but it can achieve significantly better molecular sensitivity with the use of targeted fluorescent dyes. Optical polarimetry has potential to detect the concentration of helical molecules, such as glucose. All of these methods are noninvasive or minimally invasive.The work is organized into four specific aims. The first is the design and implementation of a fast, high resolution, endoscopic OCT system to facilitate minimally invasive mouse colon imaging. The second aim is to demonstrate the utility of this system for automatically identifying tumor lesions based on tissue microstructure. The third is to demonstrate the use of contrast agents to detect molecular expression using OCT and LIF. The last aim is to demonstrate a new method based on optical polarimetry for noninvasive glucose sensing.

Measuring the Mueller matrix with optical coherence tomography (OCT) makes it possible to acquire the complete polarization properties of scattering media with three-dimensional spatial resolution. We first proved that the measured degree-of-polarization (DOP) of the backscattered light by OCT remains unity-a conclusion that validated the use of Jones calculus in OCT. A multi-channel Mueller-matrix OCT system was then built to measure the Jones-matrix, which can be transformed into a Mueller matrix, images of scattering biological tissues accurately with single depth scan. We showed that when diattenuation is negligible, the round-trip Jones matrix represents a linear retarder, which is the foundation of conventional PS-OCT, and can be calculated with a single incident polarization state although the one-way Jones matrix generally represents an elliptical retarder; otherwise, two incident polarization states are needed. We discovered the transpose symmetry in the roundtrip Jones matrix, which is critical for eliminating the arbitrary phase difference between the two measured Jones vectors corresponding to the two incident polarization states to yield the correct Jones matrix. We investigated the various contrast mechanisms provided by Mueller-matrix OCT. Our OCT system for the first time offers simultaneously comprehensive polarization contrast mechanisms including the amplitude of birefringence, the orientation of birefringence, and the diattenuation in addition to the polarization-independent intensity contrast, all of which can be extracted from the measured Jones or the equivalent Mueller matrix. The experimental results obtained from rat skin samples, show that Mueller OCT provides complementary structural and functional information on biological samples and reveal that polarization contrast is more sensitive to thermal degeneration of biological tissues than amplitude-based contrast. Finally, an optical-fiber-based multi-channel Mueller-matrix OCT was built and a new rigorous algorithm was developed to retrieve the calibrated polarization properties of a sample. For the first time to our knowledge, fiber-based polarization-sensitive OCT was dynamically calibrated to eliminate the polarization distortion caused by the single-mode optical fiber in the sample arm, thereby overcoming a key technical impediment to the application of optical fibers in this technology.

A key challenge in architecting a multicore processor is efficiently maintaining cache coherence. Directory protocols offer a scalable, bandwidth-efficient solution to this problem, but unfortunately they incur significant area overheads. This dissertation proposes three novel coherence directory designs that address the challenge of maintaining coherence in multicore processors, while reducing the area and energy overheads of the directory structure. Firstly, I propose the Phantom directory that leverages the abundance of storage in large shared caches to reduce the area devoted to a dedicated coherence directory. This approach faces a significant challenge since an access to the shared cache typically requires more energy than for a smaller dedicated directory. Phantom attempts to overcome this challenge by exploiting the spatial locality common to most applications, and by utilizing a very small dedicated directory cache, but the costs of accessing the shared cache still outweigh Phantom's area savings. Building upon the simple observation that at any point in time, large, continuous chunks of memory are often accessed by only a single core, my second proposed design, the multi-grain directory (MGD), takes advantage of this common application behaviour to reduce the directory size by tracking coherence at multiple different granularities. I demonstrate that a practical dual-grain directory (DGD) provides a robust solution, reducing directory area by 41% while maintaining good performance across a variety of workloads. While MGD provides a practical approach to reducing directory area, my third proposed design, the Tagless directory, takes a more innovative approach to achieving true scalability. Tagless embraces imprecision by embedding sharing information in a number of space-efficient Bloom filters. Careful consideration produces an elegant design with robust performance comparable to an ideal coherence directory. For a sixteen core processor, Tagless reduces directory area by up to 70% while reducing cache and directory energy consumption. My analysis also indicates that Tagless continues to provide an area and energy efficient directory as processors scale to tens or even hundreds of cores. These three innovative designs advance the state-of-the-art by providing more area and energy efficient coherence directories to allow multicore processors to scale to tens or hundreds of cores.

Suicide ideation is a growing phenomenon that can be observed in stressful environments such as those of a correctional official, and it is a cause for concern. Suicide ideation is seen as the first step of suicidal behaviour and refers to thoughts, cognitions and overt intent to kill oneself. The root causes for correctional officials experiencing such a severe state of hopelessness that they feel death must be the only escape, can be ascribed to different factors. The objective of this research is to establish the relationship between psychological strengths, stress and suicide ideation of employees of the Department of Correctional Services (DCS). Three concepts of psychological strength namely locus of control, sense of coherence and affect as independent variables, were compared, with suicide ideation as a dependant variable. The relationship between suicide ideation and stress as an independent variable was also established. A cross-sectional design was used. A simple random sample (n=157) was taken from correctional officers from a management area in the Freestate Province. The Work Locus of Control Scale, Orientation to Life Questionnaire, Affectometer 2, and the Adult Suicide Ideation Questionnaire were administered. In addition, the Correctional Officer Stress Inventory was developed and administered. Principal component and factor extraction with Oblique rotation, Cronbach alpha and inter-item correlation coefficients, factor analysis, a discriminant analysis and a stepwise multiple regression analysis were used to analyse the data. Results showed that positive affect and external locus of control were associated with suicide ideation. / Thesis (M.A. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2004.

Continuous changes in the security systems around the world, along with the increased pressure to perform may result in feelings of distrust, strain in interpersonal relations, psychological strain, fatigue and tension, all affecting the well-being of employees, especially among protection services members. Work wellness becomes an important aspect when focusing on the safety of people to whom the protection services delivers a service, as well as when the focus is on the safety of these members. Burnout and work engagement are specific focus areas in this regard. To measure burnout and work engagement, it is important to use reliable and valid instruments. Along with burnout and work engagement there are other focus areas that can have a direct influence on these dimensions, namely the perception of organisational politics. The impact of perceptions of organisational politics on burnout and work engagement can be moderated or mediated by sense of coherence. The objective of this study was to determine the relationship between work wellness, organisational politics and sense of coherence through the development of a model of work wellness for protection services members comprising of burnout, work engagement, organisational politics and sense of coherence. The research method consists of a literature review and an empirical study. A cross-sectional survey design was used to collect the data. An availability sample (N = 341) from protection services members was taken. The Maslach Burnout Inventory - General Survey (MBI-GS), Utrecht Work Engagement Scale (UWES), Perceptions of Organisational Politics (POPS), Orientation to Life Questionnaire (OTLQ) and a biographical questionnaire were administered. The statistical analysis was carried out with the help of the SPSS-programme and AMOS. The statistical methods utilised in the article consisted of descriptive statistics, Cronbach alpha coefficients, exploratory factor analysis, Pearson product-moment correlation coefficients and structural equation modelling methods. vii Exploratory factor analysis confirmed a two factor model of burnout, consisting of burnout (exhaustion and cynicism) and professional efficacy which represented the data quite well after certain items were left out. In previous research among protection services members two factors in the UWES could also be extracted namely vigour/dedication and absorption. The MBI-GS and UWES both showed acceptable internal consistencies. The analysis of Pearson correlations in this study showed that burnout is negatively related to Vigour/dedication and sense of coherence. Professional efficacy is positively related to Vigour/dedication and absorption. Vigour/Dedication is positively related to absorption and sense of coherence. Prolonged exposure to things like criminal aspects, life-and-death decision making and general political behaviour at organisational level, can result in feelings of burnout. Negative perceptions of organisational politics resulted in higher levels of burnout experienced by protection services members. Sense of coherence mediated the effect of organisational politics on work wellness. Recommendations for future research were made. / Thesis (M.A. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2005.

The aim of this research was to determine the way in which informal caregivers of HIV/AIDS patients experience their task as caregivers as well as to identify factors, or general resistance resources, which exercise an influence on their psychological well-being, and more specifically on their sense of coherence. The stressors encountered by informal caregivers of HIVIAIDS patients have previously been investigated thoroughly in a number of studies. The tasks of informal caregivers very often encompass much more than what would be, for example, included in the nursing context and therefore exceed the limits applying to the formal sector. Stressors to which caregivers are exposed include physical, financial and emotional aspects. It has been proved that this state of affairs has a negative impact on their physical health conditions as well as their psychological well-being. Caregivers do, however, at times report a certain extent of growth experienced by them which can be related to the care giving situation. The salutogenic perspective allows for a study of the origin of health and has, for the purposes of this study, been applied to obtain an alternative description of the caregivers' experiences. According to this perspective health does not merely mean the absence of disease, but also refers to health being influenced by an individual's management of stressful events. When an individual, even if confronted with stressful circumstances, has adequate general resistance resources at his/her disposal, a strong sense of coherence can develop and this will have a positive influence on his/her psychological well-being. In the South African context little if any literature can be found on the salutogenic factors that may affect informal caregivers of HIV/AIDS patients. The investigation of this study was based on an availability sample consisting of 8 informal caregivers of HIVIAIDS patients. A one shot cross sectional design with triangulation of data assessment techniques was used. The researcher obtained data with regard to the caregivers' sense of coherence by means of the Sense of Coherence Scale (SOC) (Antonovsky, 1987). Semistructured interviews were conducted with all the caregivers involved and a qualitative analysis followed. The results revealed that informal caregivers' sense of coherence was much lower than- that of a group of nurses (formal caregivers) as described by Cilliers (2003). One of the reasons for this significant difference could be the lack of a structured setting or environment in which caregivers still have to perform their duties and responsibilities. According to the results a variety of factors exercising a negative impact on informal caregivers' sense of coherence could be identified. These included (a) stress, (b) exposure to unfamiliar situations, and (c) a lack of counselling skills. Within the framework of the salutogenic perspective there were, however, different factors also known as general resistance resources, that exercised a positive impact on the caregivers' sense of coherence. Among these the following could be counted: (a) spirituality, (b) insight into interpersonal situations, (c) utilisation of social support systems, and (d) multi-disciplinary cooperation. It would therefore seem that informal caregivers do possess general resistance resources which enable them to persevere with their tasks as caregivers in spite of the stressors they encounter on a daily basis. One of the recommendations that can be posed after having carried out this study and after having analysed the results, is the compilation as well as the evaluation and implementation, of a psycho-education training programme for informal caregivers, with special emphasis on such general resistance resources. / Thesis (M.A. (Psychology))--North-West University, Potchefstroom Campus, 2006.

In the final paper for master’s degree the peculiarities of correlations between educators’ sense of coherence and well-being are discussed. The pedagogical characterization of educator’s profession and conception of coherence is tendered after thorough analysis of papers and researches of Lithuanian and foreign authors. The course, methods and data of research on educators’ coherence and well-being are discussed in the paper. The sense of coherence of educators is analyzed according to their social–demographic data, way of live and psychological well-being. The statistical analysis was accomplished to estimate the peculiarities of well-being. The typology of educators’ who took part in a survey and results of cluster analysis are presented in the paper. The peculiarities of correlations between educators’ sense of coherence and well-being are discussed in various aspects. After summarizing all the data conclusions and propositions are presented.

The purpose of this work is indentify adults diabetic people sense of coherence ,psichological feel,and self esteem.Received reseach results confirmed first hipothesis, that sense of coherence to diabetic importantly lower than to healthy individuals.Received research results confirmed second hipothesis ,that psychological well being to diabetics adult individuals is importantly worse than to healthy individuals.Received research results confirmed third hipothesis ,that self esteem to diabetics adult individuals importantly smaller than to healthy individuals.