Night shift or non-standard work continues to grow throughout the economy (Beers, 2000). Women's roles in society are changing as they find themselves having to join the work force due to economic need. South African women most of whom are mothers are no exception in this regard. Many of these mothers are obliged to do night shift work. Sectors like manufacturing and public-oriented industries often use shift work to ensure efficient continuous operation and uninterrupted response to the needs of society. This article aims to explore the role that night shift work plays in the relationships between mothers and their adolescent children; whether the mutual perceptions of night shift working mothers and their adolescent children regarding their relationships differ from those of non-shift working mothers and their adolescent children; and whether there is a difference between the night shift working group and the non-shift working group with regard to the perceptions of their relationships. Lastly, the article aims to determine the reliability of the measuring instrument that was used in this study, namely the Parent-Adolescent-Relationship-Questionnaire (PARQ). Available literature shows that shift work has a negative impact on health, for example stress-related illnesses due to lack of sleep (Akerstedt, 1998, 2003; Fletcher & Dawson, 1997, 2001; Presser, 2005). Family life is also affected and relationship difficulties have been reported (Chang, Wang, & Liu, 1993; Holland, 2004; Grosswald, 2003, 2004; Presser, 1995, 2000, 2003, 2005), while shift work is seen as a threat to family cohesion. Adolescence is a critical developmental stage and mothers have an important role to enhance healthy adolescent development in terms of issues like self-identity and autonomy. The mother's unusual working hours can have a negative impact on the mother-adolescent relationship. A cross-sectional design was used in this study. There were two groups: 35 night shift working mothers and their adolescent children, and 35 non-shift working mothers and their adolescent children. Participants were requested to complete a PARQ questionnaire. Data was analysed by means of SAS and SPSS programmes. Descriptive statistic methods such as central tendency, mean and median, variability, range and standard deviation, skewness and kurtosis were used to explore data. Independent and dependent t-tests were used to determine differences between the mean scores of the night shift working and non-shift working mothers and their adolescent children. The effect size was used to provide an objective measure of a practical effect. The findings indicate that PARQ is a reliable measure for this study as it showed good internal consistency. The skewness and kurtosis indicate acceptable normality. Adolescent children of non-shift working mothers perceive communication with their mothers as more efficient than adolescent children of night shift working mothers, and there is an indication of a significant practical effect. Adolescent children of non-shift working mothers have a more positive perception of the Mothers' Problem Solving than adolescent children of night shift working mothers, with indications of a significant practical effect between the two groups. There is no statistically significant difference between and no significant practical effect in any of the variables concerning the two groups of mothers, as reflected in Table 4. However, Table 5 shows a difference between the perceptions of the two groups of adolescents. There is a statistically significant difference between Cohesion for non-shift working mothers and for their adolescent children, with an indication of a significant practical effect. Tables 5 and 6 show a statistically significant difference between Conventionalisation of the two groups, with an indication of a significant practical effect. Both night shift working and non-shift working mothers have a more positive perception of Conventionalisation than their adolescent children. Findings also indicate a statistically significant difference in Global Distress between night shift working mothers and their adolescent children, with an indication of a significant practical effect. Night shift working mothers experience higher levels of Global Distress than their adolescent children. For both groups -night shift working mothers and their adolescent children; and non-shift working mothers and their adolescent children there is a statistically significant difference between the mothers' and the adolescents' perception of Ruination. This study has several limitations and it is recommended that future studies use a larger sample size and include longitudinal studies. Future research should also explore the construct of the night shift working mother's parenting style and their coping strategies. Father-adolescent relationships should also be a research focus. In some families in both groups, the study created a platform for dialogue between adolescents and their mothers. / Thesis (M.A. (Clinical Psychology))--North-West University, Potchefstroom Campus, 2010.

This thesis presents a study of high-redshift obscured (type-2) quasars, selected at mid-infrared and radio wavelengths. This population had remained elusive, even to hard X-ray surveys, and in Chapter 2 I compare the selection of type-2 quasars in X-ray and mid-infrared surveys, as well as explaining the criteria I will use to search for these objects at z ~ 2, around the peak in the unobscured (type-1) quasar activity. Chapter 3, presents a sample of radio-intermediate type-2 quasars selected from the criteria de- scribed in Chapter 2. Optical spectroscopy shows indeed that at least half of the objects have the characteristic narrow emission lines, and lie around the expected redshift of z = 2. The other half of the objects are consistent with also being type-2 quasars at similar redshifts, although no emission lines are visible. In Chapter 4,1 discuss the possibility of two types of obscured quasars, some obscured by a dusty torus and some by a dusty host galaxy, to explain the lack of emission lines in half of the sample. I model the number of type-1 quasars expected to follow similar selection criteria and at the same redshifts as our type-2 quasars, and find that the obscured quasars outnumber the unobscured by a ~2-3:1 ratio. I conclude that most supermassive black hole growth is obscured by dust. When comparing this to predictions from unified schemes, I find that this result is only consistent with the schemes provided host-obscuration is indeed happening. The lower ratio of type-2 to type-1 quasars inferred from X-ray surveys (~1:1) suggests that some of the type-2 quasars in this sample might be Compton thick. Radio data taken at three frequencies, are presented in Chapter 5, to study the spectral properties and intrinsic luminosities of our sample. I show that some type-2 quasars have flat radio spectra, which is inconsistent with obscuration by the torus, but consistent with host-obscuration. Some gigahertz-peaked spectra, characteristic of young radio jets, are present, but the majority of the sources have very steep spectra. These steep spectral indices can be explained by active developed jets in which continuous injection of electrons is accompanied by inverse-Compton losses against the cosmic microwave background. In Chapter 6, I select a similar sample of type-2 quasars in a different field, where X-ray data are available. The selection criteria are kept identical, except for the radio flux density cut, which is lowered. This is expected to introduce significant numbers of starburst contaminants. To filter these out, and due to a lack of spectroscopy, I use a bayesian method to fit the spectral energy distributions, obtain photometric redshifts, and select between a quasar and a starburst model. I measure the X-ray properties for the resultant sample of type-2 quasars. The entire sample is found to be Compton-thick, and repeating the modelling of Chapter 4, I find that the population of Compton-thick quasars is at least comparable to the population of unobscured quasars, and probably larger.

This study is a prospective longitudinal outcome study investigating the presence of response shift in disease and generic functional outcome measures in 105 patients undergoing spinal surgery. The then-test method which compares pre-test scores to retrospective pre-test scores was used to quantitate response shift. There was a statistically significant response shift for the Oswestry Disability Index (ODI) (p=0.001) and the Short Form-36-PCS (p=0.078). At three months, seventy-two percent of patients exhibited a response shift with the ODI. Fifty-six and 21 percent of patients exhibited a response shift with the SF-36 physical and mental component scores respectively. When accounting for response shift and using the minimal clinically important difference, the success rate of the surgery at 3 months increased by 20 percent. The presence of response shift has implications for the measurement properties of standard spinal surgery outcome measures including the effect size of treatment and the number of responders to treatment.

This study is a prospective longitudinal outcome study investigating the presence of response shift in disease and generic functional outcome measures in 105 patients undergoing spinal surgery. The then-test method which compares pre-test scores to retrospective pre-test scores was used to quantitate response shift. There was a statistically significant response shift for the Oswestry Disability Index (ODI) (p=0.001) and the Short Form-36-PCS (p=0.078). At three months, seventy-two percent of patients exhibited a response shift with the ODI. Fifty-six and 21 percent of patients exhibited a response shift with the SF-36 physical and mental component scores respectively. When accounting for response shift and using the minimal clinically important difference, the success rate of the surgery at 3 months increased by 20 percent. The presence of response shift has implications for the measurement properties of standard spinal surgery outcome measures including the effect size of treatment and the number of responders to treatment.

Understanding recent decades of coral community change has been hindered by a shortage of long-term monitoring and a lack of tools that provide a lasting record of benthic reef communities. To increase our understanding of Caribbean coral reef dynamics, this dissertation research developed and used innovative technologies involving landscape mosaic images and 3D reef models, to analyze a novel 40 year dataset of coral community health from Andros Island, Bahamas. Historical data from Andros Island (1968-2000) were provided as part of a Cooperative Research and Development Agreement (CRADA) between the University of Miami and the Naval Undersea Warfare Center Division Newport. Long-term monitoring at Andros Island revealed that reef decline was a-typical over recent decades. Coral mortality and disease increased significantly between 1970 and 2000, whereas macroalgal cover did not. To complement studies of coral mortality and disease, the resilience and resistance of individual coral species at Andros were measured from 1972 to 2008. Of the 24 species studied, only three (Siderastrea siderea, Montastraea cavernosa, and Porites astreoides) were resistant to recent disturbance histories, whereas Porites porites was resilient. Further studies using 3D models explored relationships between coral population dynamics and spatial patterns of coral species. Results indicated that the arrangement of dominant coral species and the processes of recruitment, growth, and mortality were non-random over time. In summary, the application of mosaic images and 3D reef models to a previously un-published long-term coral health dataset led to improved understanding of factors controlling past reef communities.

Mode of access: World Wide Web. / Thesis (Ph. D.)--University of Hawaii at Manoa, 2004. / Includes bibliographical references (leaves 180-192). / Electronic reproduction. / Also available by subscription via World Wide Web / xviii, 192 leaves, bound col. ill. 29 cm

Astrophysical models that address stellar energy generation and nucleosynthesis require a considerable amount of input from nuclear physics and are very sensitive to the detailed structure of nuclei, both stable and unstable. Radioactive nuclei play a dominant role in several stellar environments such as supernovae, X-ray bursts, novae etc. and nuclear data are important in the interpretation of these phenomena. When carbon, nitrogen and oxygen isotopes are present in substantial quantities in a star of sufficient mass, the fusion of four hydrogen nuclei to form a helium nucleus proceeds via the CNO cycles. Energy release in the CNO cycles is limited by the long lifetimes of 14O and 15O. In explosive stellar scenarios such as X-ray bursts, the energy output is very large, suggesting a breakout from the CNO cycles. 15O(α,γ)19Ne is the first reaction that breaks out of the CNO cycle. Nuclear structure information on high lying states in 19Ne is required to calculate the rate of the 15O(α,γ)19Ne reaction. This work focuses on the study of states in 19Ne above 3.53 MeV. The lifetimes of five states in 19Ne above 3.53 MeV were measured in this work. The states in 19Ne were populated via the 3He(20Ne,α)19Ne reaction at a beam energy of 34 MeV. The lifetimes were measured using the Doppler Shift Attenuation Method. The lifetimes of five states were measured and an upper limit was set on the lifetime of a sixth state. Three of the measurements are the most precise thus far. The lifetimes of the other three states agree with the values of the only other measurement of the lifetimes of these states. An upper limit on the rate of the 15O(α,γ)19Ne reaction was calculated at the 90% confidence level using the measured lifetimes. The contributions to the 15O(α,γ)19Ne reaction rate from several states in 19Ne at different stellar temperatures are discussed.

Chlamydia is a clinically significant organism that exhibits a unique stage-specific developmental cycle, involving the interconversion between two metabolically distinct forms. The completion of eight chlamydial genome sequences identified three different RNA polymerase sigma factor (ó) genes. Temporal gene expression analysis has predicted that each ó may play an integral role in controlling the development cycle. This thesis examines the role of the chlamydial alternate sigma factor, ó54 (rpoN) and the potential mechanism for the control the developmental cycle and disease pathogenesis. To achieve this, we searched the genome for putative ó54 promoters, validated the findings by DNA-binding assays, and examined the roles of the genes predicted to be regulated by ó54. This study applied a bioinformatics approach to search for additional ó54 regulated genes in C. trachomatis L2. A reduced consensus sequence (TGGCACnnnnnTTGC) identified two previously published ó54 promoter sequences upstream of CT652.1 and CT683. A modified consensus sequence (TGG-N9-TGC) was applied to the C. trachomatis D genome in Findpatterns yielded 512 potential targets of which 20 by virtue of sequence orientation and distance upstream of the predicted ORF start codon Primer extension analysis of total RNA isolated at 24 hours post-infection mapped the 5' RNA end upstream for acpS (CT100), yhf0_1 (CT258), SAM (CT404), lpxA (CT531), hypothetical proteins CT652.1 and CT683, and htrA (CT823) to the predicted ó54 promoters. Three candidates (CT291, CT404, and CT847) were mapped to putative ó70-like ó66 promoters. No transcript start sites were detected for the remaining ó54 promoter candidates. Two transcripts were detected from predicted ó66 and ó54 tandem promoters upstream of CT404. Primer extension analysis of the CT404 transcripts from RNA isolated at 4, 8, 12, 24 and 32 hours post-infection showed a decrease between 12 hours and 24 hours post-infection in transcripts thought to be generated from the predicted ó66 promoter. Transcripts from the predicted ó54 promoter were identified throughout development. Temporal gene expression profiles of the candidate genes with predicted ó54 promoters (CT652.1, CT683, CT100, CT258, CT531 and CT823) were resolved throughout the C. trachomatis L2 developmental cycle using real-time PCR. Transcripts for CT608 and CT609 were detected early in the cycle, while strong transcript levels were detected for CT258, CT531 and CT823 after the appearance of CT609 (rpoN). Low levels of CT652.1 and CT683 were measured, in the mid to late phase of the cycle, and transcripts for CT100 appeared at lower levels during the middle phase of the cycle. The functional assay of the predicted ó54 promoters required the generation of recombinant C. trachomatis L2 ó54 (rRpoN). The C. trachomatis rpoN was cloned into a bacterial expression system (pQE70) and the recombinant proteins purified for subsequent DNA mobility shift assays. Expression of rRpoN was hampered by low copy numbers, and unusual physical characteristics. DNA binding and mobility shift assays using rRpoN extracts against the chlamydial CT652.1 ó54 promoter, plus two characterised E. coli ó54 promoters (hypA and hycA), were successful if E. coli core RNA polymerase was added to the assay. All 20 candidates with predicted ó54 promoters were analysed with EMSA using rRpoN extract. The promoters upstream of CT100, CT223, CT258, CT322, CT652.1 and CT683 showed affinity towards the recombinant rRpoN-E. coli core RNA polymerase holoenzyme complex. Searches for potential chlamydial ó54 transcription initiation activators were made using the Multiple Em for Motif Elucidation (MEME) software, looking to identify the DNA binding motifs. The upstream promoter regions of CT100, CT223, CT258, CT322, CT531, CT652.1, CT683 and CT823 in C. trachomatis L2 and orthologs found in other species of Chlamydia were analysed. The software identified a near palindromic sequence upstream of CT100 orthologs in C. trachomatis D and C. trachomatis MoPn (CAACCCAAC and CACCACAAC) where as a CT531- and CT823-specific motif was also discovered (CCGTTGTAGAATCTC). It is beginning to emerge that ó54 may regulate the expression of proteins required for the formation of the cell wall. Since the expression of the ó54 transcript, rpoN, coincides with the morphological change from the non-infectious RB to the infectious EB, predictions could be made concerning which genes are potentially regulated by ó54.

Coal gasification is currently being developed as a cleaner alternative to conventional combustion technology. To optimise H2 production in this process, a water gas shift reaction is utilised to convert all CO with H2O to produce CO2 and H2. Typically industrial processes involve a two-step reaction system followed by a downstream H2 purification system, though attracting significant inefficiencies and high capital costs. Replacing a conventional unit process with a membrane reactor in this application is foreseen to provide major advantages: • Removing H2 from the reaction in-situ, a membrane reactor can minimise downstream processing and associated capital and operational costs. • Shift the reaction to higher conversions, improving efficiencies and reducing CO in the outlet. • Provide a purified H2 stream for use in PEM fuel cells, while concentrating the CO2 stream at high pressure for possible sequestration. If the concept of membrane reactor is to be adopted in coal gasification, important material improvements and operational challenges must be overcome before commercialisation can be realised. In addition, the water gas shift reaction has only recently gained interest for membrane reactors and is currently lacking comprehensive research on the effects of operating conditions on both the conversion and separation found within the unit. To this end, these are strong motivations of this work to contribute with knowledge in this field of research. This thesis examines the effects of operating conditions such as temperature, pressure, space velocity, sweep gas rate and feed water ratio on the performance of a water gas shift membrane reactor as compared with a conventional reactor. Novel cobalt silica molecular sieve membranes were used with conventional low temperature water gas shift reaction CuZnAl2O3 catalysts. Two type of membrane reactor configuration were investigated: a small flat template with catalyst on the feed side, and a scale up tube membrane with catalyst placed also in feed stream, the inner shell of the tube membrane. The cobalt silica membranes complied with activated transport, following a flux dependency gas permeation, where He and H2 permeance increased with temperature whilst N2, CO and CO2 showed the opposite effect. Best single gas selectivities were very high, with values of 4500 (He/N2) and 1100 (H2/CO2). In addition, the energy of activation for He and H2 was also very high, in excess of 9-10 kJ.mol-1, clearly indicating the high quality of the membranes employed in this study. It was found that the MR improved CO conversions for a range of space velocities as a function of temperature, which was attributed to both activate transport property of the membrane and increased conversion. Below equilibrium limits this provided an improved H2 production of 5 – 12% at 200-250oC as the removal of H2 through the membrane allowed enhanced conversion. With a set feed rate, the optimum advantage of the MR was seen at a water ratio of 1 as the lower equilibrium limits allowed greater potential for conversion enhancement. With increasing excess water this advantage decreased from 7% down to 0.5% at 300oC. The use of pressure and sweep rate was used to optimise the membranes permeation rate and selectivity. While pressure (or driving force) provided the highest potential for increasing permeation (or flow rate), temperature in tandem with pressure provided the greatest improvement in membrane selectivity, thus increasing H2 concentration from 95 – 99% in the permeate stream. Detailed study of permeate concentrations with changing conditions was undertaken to provide an understanding of the transport properties of silica membranes. It was observed that membrane selectivity and permeation decreased with the gas composition (ie Single>Binary>Ternary). Nevertheless, for separation of a ternary mixture at increased temperatures (250oC) the membrane could provide up to 99% purified H2 while reducing CO down to 700ppm. Competitive gas permeation regimes are an industrial reality which is seldom addressed in membranes for high temperature gas separation. The effect of gas mixtures on permeation and selectivity was attributed to several factors: chemical potential (or driving force) of the feed gas mixture, blockage of micropores by large molecules (CO2 and CO) which in turn affects the percolation of H2. As a result, gas separation was reduced for higher CO and CO2 feed concentrations, leading to a significant reduction in the H2 flow rate. Temperature played a vital role in this competitive process, as H2 diffusivity and CO, CO2 adsorption followed an inverse trend. Thus, increasing temperature led to higher H2 pore diffusivity, while decreasing the competitive effect of CO and CO2 adsorption. The use of cobalt modified silica to improve the hydrothermal stability of the membranes was investigated for use in the water gas shift reaction. It was found that the addition of cobalt stabilised the silica pore network, maintaining microporosity after exposure to steam. This is validated with long term stability testing in a water gas shift membrane reactor, where it was seen that the membrane could provide up to 95% H2 concentration in the permeate for over 200hrs of MR operation. This provided novel work, establishing the feasibility of these membranes for long term testing and operation in an industrial WGS MR.

Fatigue in the minerals industry of Western Australia is a greatly under-recognised issue that has serious potential consequences for shift workers at work and at home. A review of fatigue literature demonstrates the elusive nature of fatigue. It is something that most people have probably experienced at some time in their lives. It is a diffuse sensation that is accompanied by feelings of lethargy and a lack of interest in any activity. A general sensation of weariness is a major symptom of fatigue. Fatigue cannot be measured directly and subjective estimates have to be relied upon. Potentially life threatening consequences can result when shift workers perform under the influence of fatigue. Fatigue and sleepiness have the power to kill if not treated with the respect they deserve. A cross-sectional survey of five underground mines was conducted to obtain a better understanding of their fatigue risk management strategies and the views of managers and shift workers on their sleep and shift schedules. Four mines provided information on their fatigue risk management procedures. Ten underground mining crews comprising 147 shift workers provided their views by an anonymous survey questionnaire administered at each mine at the start of shift. Shift worker sleep at the five mines compared well with mines in Tasmania, New South Wales and Queensland. However, it was found that frequently waking earlier than intended was the most widely reported sleep concern for shift workers on day shift, night shift and days off. Falling asleep while on day shift and on night shift demonstrates that fatigue is an issue that can occur on day shift as well as night shift. Fatigue is not an issue that is confined to night shift. Mine fitness for work procedures focused primarily on: shift schedules, hours of work and drug and alcohol issues. The level of detail provided on fatigue risk management was considered to be less than adequate when compared with the three previous issues and fatigue risk management documentation sourced from the minerals industry and the transport industry. The survey data and fitness for work procedures provided by four mines suggests that considerably more work needs to be done to recognise and address sleep quantity and quality, as well as sleepiness and fatigue experienced by shift workers while on shift and at home on rest days. There is a serious need for the Western Australian minerals industry to recognise the vital importance of sleep to shift workers during their shift schedule and rest days. There needs to be a concerted and on-going campaign by the industry to raise and maintain the awareness of sleep as a key element in fitness for duty.