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Measurement and limitations of optical orbital angular momentum through corrected atmospheric turbulence
No full textIn recent years, there have been a series of proposals to exploit the orbital angular momentum (OAM) of light for astronomical applications. The OAM of light potentially represents a new way in which to probe the universe. The study of this property of light entails the development of new instrumentation and problems which must be addressed. One of the key issues is whether we can overcome the loss of the information carried by OAM due to atmospheric turbulence. We experimentally analyze the effect of atmospheric turbulence on the OAM content of a signal over a range of realistic turbulence strengths typical for astronomical observations. With an adaptive optics system we are able to recover up to 89% power in an initial non-zero OAM mode (ℓ = 1) at low turbulence strengths (0.30″ FWHM seeing). However, for poorer seeing conditions (1.1″ FWHM seeing), the amount of power recovered is significantly lower (5%), showing that for the terrestrial detection of astronomical OAM, a careful design of the adaptive optics system is needed.12 page(s
Correlation of BRAF mutation status in circulating-free DNA and tumor and association with clinical outcome across four BRAFi and MEKi clinical trials
No full textPurpose: Tumor-derived circulating cell–free DNA (cfDNA) is a potential alternative source from which to derive tumor mutation status. cfDNA data from four clinical studies of the BRAF inhibitor (BRAFi) dabrafenib or the MEK inhibitor (MEKi) trametinib were analyzed to determine the association between BRAF mutation status in cfDNA and tumor tissue, and the association of BRAF cfDNA mutation status with baseline factors and clinical outcome. Experimental Design: Patients with BRAF V600 mutation–positive melanoma were enrolled in each study after central confirmation of BRAF status in tumor using a PCR-based assay. BRAF mutation status in cfDNA from patient plasma collected at baseline, 732 of 836 (88%) enrolled patients in total, was determined. Results: BRAF mutations were detectable in cfDNA in 76% and 81% of patients with BRAF V600E/V600K–positive tumors, respectively. Patients negative for BRAF mutations in cfDNA had longer progression-free survival (PFS) and overall survival in each of the four studies, compared with patients with detectable cfDNA BRAF mutations. The presence of BRAF-mutant cfDNA was an independent prognostic factor for PFS after multivariate adjustment for baseline factors in three of four studies. Patients negative for BRAF mutation–positive cfDNA in plasma had higher response rates to dabrafenib and trametinib. Conclusions: BRAF mutations in cfDNA are detectable in >75% of late-stage melanoma patients with BRAF mutation–positive tumors. The lack of circulating, BRAF mutation–positive cfDNA is clinically significant for metastatic melanoma patients, and may be a prognostic marker for better disease outcome.8 page(s
Revisiting mobilisation of skeletal lead during pregnancy based on monthly sampling and cord/maternal blood lead relationships confirm placental transfer of lead
No full textLead (Pb) can be released from the maternal skeleton during pregnancy and lactation and transferred to the infant. Most support for this hypothesis comes from blood Pb (PbB) studies involving limited sampling during pregnancy, the maximum usually being five samplings, including at delivery. We provide longitudinal data for PbB concentrations and Pb isotopic ratios for three cohorts of pregnant females (n = 31), two of which are based on monthly sampling and the other on quarterly sampling. We also provide data for samples collected post-partum. The data are compared with changes observed in a matched, by country and age, non-pregnant control cohort (n = 5). The monthly data illustrate the variability between subjects, which is also apparent when the data are compared on a trimester basis. Mixed model analyses showed that, in the third trimester, the mean PbB level was significantly lower for women (n = 10) who took a calcium (Ca) supplement (PbB 1.6 µg/dL) than those whose Ca intake was low (low-Ca cohort; n = 15; PbB 2.5 µg/dL) because low Ca means more mobilisation is required for homoeostasis so that more Pb was mobilised from the skeleton. For women who took the supplement, post-partum PbB levels were significantly higher than those in the other periods (2.7 vs 1.4–1.6 µg/dL). For women in the low-Ca cohort, PbB levels were higher at post-partum than in pre-pregnancy and in the first and second trimesters (3.1 vs 1.8 µg/dL), while the levels in the third trimester were higher than those in the first and second trimesters. Importantly, the increase in PbB during gestation was delayed until the third trimester in the Ca-supplemented cohort compared with the low-Ca cohort. Regression analysis showed that the changes over trimester were very similar for PbB and the ²⁰⁶Pb/²⁰⁴Pb ratio providing convincing evidence for extra mobilisation of Pb from the maternal skeleton during pregnancy and lactation. Isotopic ratios in the cord blood samples were similar to those in the maternal blood samples taken prior to parturition with an R² 0.94 for the migrant subjects and R² 0.74 for Australian subjects for ²⁰⁶Pb/²⁰⁴Pb ratios, supporting the concept of placental transfer of mobilised skeletal stores of Pb.12 page(s
Measuring creativity in an improvised jazz context: a preliminary tDCS study
No full textEmpirical thesis.Bibliography: pages 56-62.1. Introduction -- 2. Method -- 3. Results -- 4. Discussion -- References -- Appendices.Musical improvisation involves the generation of original and contextually appropriate musical sequences. This investigation focused on whether brain stimulation applied to the motor cortex influences creativity and technical fluency in musical improvisations. Previous research on creativity has examined two important brain networks: the dorsolateral prefrontal cortex (DLPFC), which underpins attention and monitoring, and the medial prefrontal cortex (MPFC), which regulates mind wandering and mental simulation. Other research on music has examined the significance of the premotor cortices, which include the ventral and dorsal pre-motor cortex (vPMD & dPMD,respectively) and the pre-supplementary motor area (pre-SMA) that aid in the generation of musical sequences and high level of motor planning and execution. To date, the primary motor cortex (M1)has not been explored in musical creativity.The M1 mediates movement of the hand, and is also involved in the consolidation and acquisition of motor skills. This investigation examined the role of the M1 regions in creativity, motor performance and technical fluency in a jazz improvisation context. The relationship between creativity and technical fluency was also assessed. The role of the M1 regions was evaluated with transcranial direct current stimulation (tDCS), which is a non-invasive, safe and painless form of brain stimulation that modulates the neural activity over the desired area. Minute electrical currents are delivered through two saline-soaked electrodes: the positive (anodal) electrode stimulates neural activity, whilst the negative (cathodal) electrodes inhibits neural activity.Bi-hemispheric, online tDCS was applied to the M1 region of proficient musicians. Two tDCS groups were used, Anodal-Left M1/Cathodal-Right M1 (n = 4) and Cathodal-Left M1/Anodal-Right M1 (n = 4) whilst they completed a sight reading and improvisation task. The level of creativity and technical fluency of the performances were assessed by an expert adjudicator (n = 1). It was hypothesised that applying excitatory tDCS over the M1 region of proficient musicians will enhance both creativity and technical fluency compared to inhibitory tDCS. The results from the preliminary study illustrates a trend that excitatory tDCS over the M1 region enhances creativity (p =.07). Furthermore, excitatory tDCS also significantly enhanced technical fluency (p =.05) when compared to inhibitory tDCS. These preliminary results provide some evidence that the M1 region is a brain area that aids in the enhancement of creativity, technical fluency, and motor performance in an improvised jazz context with proficient musicians.Mode of access: World wide web1 online resource (107 pages) musi
The nursing experience of caring for patients living with dementia and co-morbidities on surgical wards in the acute healthcare setting
No full textEmpirical thesis.Bibliography: pages 70-76.Chapter 1. Introduction -- Chapter 2. Literature review -- Chapter 3. Method -- Chapter 4. Results -- Chapter 5. Discussion -- Chapter 6. Conclusion -- Reference list -- Appendices.Background. The complex needs of patients living with dementia and co-morbidities and the consequent growing burden on the healthcare system necessitates consideration of new ways of delivering care in the acute setting. Patients living with dementia are high users of acute care, but have poorer clinical outcomes and higher rates of mortality and adverse events in hospitals, when compared to the general population. Care of this vulnerable group is complex and time-consuming, as well as physically and emotionally demanding on nursing staff. This presents challenges to nursing staff in the acute setting.Aims. This study had four aims to: (i) explore the attitudes of nursing staff providing care to patients living with dementia and co-morbidities on surgical wards in the acute setting; (ii) measure the extent to which care was perceived by nursing staff to be patient-centred; (iii) measure the satisfaction of nursing staff with providing patient-centred care; and (iv) identify barriers and facilitators to the provision of patient-centred care to patients living with dementia and co-morbidities on surgical wards in an acute setting.Method. A mixed-method study design was used to explore the experience of nursing staff caring for patients living with dementia and co-morbidities on surgical wards in an acute healthcare setting. Participants were purposively chosen from three acute surgical wards in a tertiary metropolitan teaching hospital.Each participant completed three questionnaires and a semi-structured interview. A total of 13 registered nurses were recruited.Results. The nurses were found to have a positive attitude towards patients with dementia. They recognised the importance of establishing communication and a bond with these patients to address their unique needs and to provide patient-centred care. However, many nurses expressed frustration and stress at not being able to provide this care on the acute surgical ward. Nurses' satisfaction with providing patient-centred care was dependent on the amount of support received from the organisation in terms of resources, such as adequate staffing, and the ward environment. Barriers identified included a lack of time and resources to provide patient-centred care and a lack of training to acquire the skills needed to care for this vulnerable group. Facilitators to patient-centred care included strategies or 'work-arounds' to provide safe care and extra nursing staff, called patient specials, who provided constant patient supervision.Conclusion. Despite the significant relationship between the nursing staff-patient experiences, there is a lack of research focusing on the staff experience of providing patient-centred care to patients living with dementia and co-morbidities on surgical wards in the acute setting. Understanding the nursing staff experience of providing patient-centred care in this setting and using this knowledge to develop and improve systems to support excellence in care is needed.Mode of access: World wide web1 online resource (76 pages, 25 unnumbered pages) diagrams, graphs, table
(Super)naturalism and Big Gods
No full textTheoretical thesis.Running title: (Super)naturalism and Big Gods.Bibliography: Pages 73-85.1. Introduction -- 2. Method -- 3. Results -- 4. DiscussionThe contribution of perceived supernatural punishment to large-scale cooperation, specifically integral to Norenzayan's Big Gods (2013), remains unresolved. This study aims to deduce the contributing effect of three of Norenzayan's main factors in a perceived cooperative task; religious affiliation, individual versus large-scale interaction, and the threat of punishment versus no punishment. Community and Punishment are manipulated within a population that explicitly denies the existence of God, compared to a population who inherently believes, or does not deny, the existence of God (atheists and non-atheists). The combination of the Community and Punishment conditions is hypothesised to result in the highest levels of prosociality (despite religious affiliation). The effects of Community and Punishment in those who are assumed to rely on non-supernatural institutions as foundations for cooperation (atheists representing a 'pre-religious' population) versus those who are assumed to rely currently on supernatural institutions as foundations for cooperation (non-atheists; agnostic and religious participants, representing a 'peri-religious' population) reveal differential behavioural predictors. Experimental manipulations predict prosociality for atheists, whereas supernatural belief score predicts prosociality for non-atheists. In the absence of targeted religious priming effects, perception of supernatural is not the most compelling explanation of the data. The role of supernatural beliefs in the induction of cooperative schemas is not dismissed, but proposed to exist within methodological, contextual and cultural boundaries of wider inference, encompassing both the supernatural and the secular. The contribution of supernatural belief, by extension, is neither insignifical nor necessary overall.Mode of access: World wide web1 online resource (ix, 97 leaves) illustration
When invisible becomes visible: experiences with the long cane
No full textTheoretical thesis.Bibliography: pages 77-85.Chapter 1. Introduction -- Chapter 2. Disability models and stigma theory -- Chapter 3. Vision impairment, children and cane use -- Chapter 4. Empirical research -- Chapter 5. Methods -- Chapter 6. Results -- Chapter 7. Discussion -- Chapter 8. Conclusion.Research into disability and stigma has portrayed an overly pessimistic view of responses to stigma by failing to incorporate recognition of stigma-related experiences as potentially being part of a generally positive experience. Further to this, research has focused on dividing benefits and burdens of parents of children with disabilities rather than presenting these aspects in a holistic manner. This study aimed to identify parental perceptions of stigma that may impact interactions in public places, specifically seeking to answer the question: what are the range of public-based experiences of parents of children who are vision impaired? Furthermore, does the presence of the long cane alter these experiences? Semistructured interviews and the Parenting Daily Hassles Survey were utilised to identify parental perceptions of public reactions to their child’s long cane use. Stigma theory was used to analyse interview transcripts to also ascertain the extent to which stigma was present within experiences. Findings of the study identified the presence of not only stigma, but also positive experiences and the ability for individuals to be resilient. Parental reactions to public responses also seemed to vary depending on context and the level of stress arising from other factors. This study has found that although the long cane is viewed as a stigma symbol, it is, most importantly, a symbol of freedom and independence. Unlike much of the previous research on disability and stigma, this study demonstrates that allowing a broader focus beyond stigma when collecting and coding interviews, reveals that some situations containing elements of stigma are perceived as positive overall.Mode of access: World wide web1 online resource (vii, 144 pages
Dams development and rights of indigenous peoples: a legal perspective on the proposed Tipaimukh Dam in Northeast India
No full textTheoretical thesis.Bibliography: Pages 65-76.1. Introduction -- 2. Research plan and methodology -- 3. Literature review -- 4. Current development -- 5. Case laws and people power -- 6. Legal authority of the Governments -- 7. Laws and regulations supporting people -- 8. International safeguards -- 9. Alternative sources of power -- 10. Conclusion showing encouraging signs -- 11. Bibliography.Tipaimukh dam is a proposed 1500 MW hydroelectric project in Northeast Indian State of Manipur. According to the Indian government a large scale hydroelectric dam is necessary for the overall electricity demand of the country and to generate local employment, promote pisciculture, tourism, navigation, flood control and irrigation. The local people are against the dam because it will submerge thousands of houses and will destroy the livelihood of indigenous Hmar and Zeliangrong Naga peoples. It will also destroy the biological diversity of the area including endangered species of flora and fauna.Most of the literature in the field is focused on the socio-economic and environmental effects of the dam. In my research I will examine the building of the dam from a legal perspective. I will adopt a comparative critical framework to analysis the laws and regulations that could enable the government to build such a dam and also the legal instruments that the people could use to oppose the dam. I will also build my argument an case studies of successful court cases and people's movement from India and around the world. As the indigenous peoples are closely related to the environment and land, I will focus on laws relating to the protection of indigenous people's land rights and protection of the environment. I will also look at alternative sustainable sources of producing electricity that could be adopted to save the people and environment.There is a strong chance that the government might decide not to proceed with the project due to its adverse effects on the people and environment, but if it does then the people will have to go to the court as the last resort. My research will be focussed on the legislation and precedents that could be useful in such a court case.Mode of access: World wide web1 online resource (vii, 76 leaves
Hearing loss and hearing gained: the prevalence of hearing loss and efficacy of hearing aid donation in the Philippines
No full textThesis by publication.Bibliography: pages 135-146.Chapter 1. Introduction -- Chapter 2. Hearing loss in the Philippines -- Chapter 3. Measuring hearing handicap, a profound conundrum. Discovering the limitations of a Tagalog translation of the Hearing handicap inventory for the elderly and adult screening questionnaire -- Chapter 4. Evaluation of a hearing aid donation programme in the Philippines Part I : IOI-HA outcomes -- Chapter 5. Evaluation of a hearing aid donation programme in the Philippines Part II : objective, self-reported and performance measures -- Chapter 6. Conclusions.The limited data available on the prevalence of hearing loss in low and middle income countries indicate that it is highly prevalent and associated with a high burden of disease, such as delayed speech and language development, social isolation, and decreased educational and vocational attainment. This, coupled with a high rate of economic hardship and lack of public health services, suggest that there is a vast unmet need for hearing healthcare services. Philanthropic hearing aid donation programs attempt to bridge this gap, however, no research on the effectiveness of philanthropic hearing aid donation programs exists in the literature. This is partly because few locally translated and normed hearing aid outcome measures exist in many of these countries.In a series of four papers focussed on the Philippines, this thesis investigates; the prevalence of hearing loss in adults and children, the effectiveness of a hearing aid donation program, and the psychometric properties of two translated outcome measures - the hearing handicap inventory short-form for adults and the elderly (HHIA-S and HHIE-S), and the international outcomes inventory for hearing aids (IOI-HA). Results show a high prevalence of hearing loss, compared with high income countries, and regional neighbours. In mild-severely impaired adults, the HHIA-S and HHIE-S showed psychometric properties similar to previous reports; but were insensitive to profound loss. The IOI-HA also showed psychometric properties in line with previous reports, however there was a lack of correlation to objective measures of hearing aid fitting. Additionally, the majority of donated hearing aids were broken or significantly under-fit six months after fitting. These findings highlight the high burden of disease of hearing loss in the Philippines, limitations of hearing aid donation programs, and limitations of outcome measures when applied in such populations.Mode of access: World wide web1 online resource (1 online resource (xiv, 146 pages)) diagrams, table
Quantum phase estimation in noisy systems
No full textEmpirical thesis.Bibliography: pages 79-87.1. Introduction -- 2. Loss-resistant unambiguous phase measurement -- 3. Quantum enhanced spectroscopy -- 4. Magnetometry with an NV centre -- 5. Estimation of a time varying phase -- 6. Conclusions.The precision in estimation of unknown parameters can go beyond the classical limits by using nonclassical properties of quantum mechanics. However, nonclassical properties are very sensitive to the interaction with environment. This interaction could result in the loss of photons and low visibility. The purpose of this thesis is to find states and measurement schemes which give enhancement in estimation accuracy over the classical methods in the presence of such effects.We begin with estimation of an unknown phase in a Mach-Zehnder interferometer in the presence of photon loss. We propose a scheme to produce states which are loss-resistant and perform very close to optimal states. We propose sequences of such states combined with single photon states to obtain an unambiguous phase estimate with better accuracy than the standard quantum limit.We then consider the case that the loss is due to the interaction of the beam with an ensemble of atoms. Traditionally, the transition frequencies of atoms are measured via absorption, but there is also information available in the phase shift. We numerically find states that give maximum information about the transition frequency, obtained from both the absorption and the phase and quantified by the Fisher information.We also consider phase estimation in a Ramsey interferometer using an NV centre to measure an unknown time-independent magnetic field. The low visibility in Ramsey measurements requires different measurement schemes than optical interferometers. We find an optimised adaptive scheme which reaches the limit analogous to the Heisenberg-like scaling in the estimation of the magnetic field, and outperforms the optimal non-adaptive scheme.Finally, we consider continuous measurement on a single spatial mode field with a time varying phase. We consider a phase which varies in time with power law spectral density. We show that by using squeezed coherent states in an adaptive homodyne measurement scheme we can estimate the phase with accuracy scaling at the Heisenberg limit.Mode of access: World wide web1 online resource (xviii, 87 pages) diagrams, graph