97 research outputs found
Phase planes in the universe : chaotic cyclic universes and kicking Chameleons
No full textThis thesis consists of two main sections: chaotic cyclic cosmology and Chameleon gravity in the early universe. Both sections invoke a phase plane analysis as their commonality. The first explores a cyclic model, proposed by Ellis et al, that is in keeping with current observations. No exotic nor new physics is needed for the bounce nor the turnaround. The model is chaotic in nature and requires only that the universe is closed and that dark energy (at some time) decays. The second section contests the claim by Burrage et al. that Chameleon gravity is inconsistent in the early universe, unless constraints on its coupling mechanism are significantly increased. It is shown that the addition of a Dirac-Borne-Infeld (DBI) correction - a consistent, high energy modification - to the Chameleon dynamically renders it weakly coupled to matter. This is done without any fine-tuning and ensures the consistency of the Chameleon at all scales without infringing upon its crucial feature as a dark energy candidate: its elusive but prominent coupling to matter
Computational analysis techniques using fast radio bursts to probe astrophysics
No full textThis thesis focuses on Fast Radio Bursts (FRBs) and presents computational techniques that can be used to understand these enigmatic events and the Universe around them. Chapter 1 provides a theoretical overview of FRBs; providing a foundation for the chapters that follow. Chapter 2 details current understandings by providing a review of FRB properties and progenitor theories. In Chapter 3, we implement non-parametric techniques to measure the elusive baryonic halo of the Milky Way. We show that even with a limited data set, FRBs and an appropriate set of statistical tools can provide reasonable constraints on the dispersion measure of the Milky Way halo. Further, we expect that a modest increase in data (from fewer than 100 FRB detections to over 1000) will significantly tighten constraints, demonstrating that the technique we present may offer a valuable complement to other analyses in the near future. In Chapter 4, we study the fine time-frequency structure of the most famous FRB: FRB 121102. Here, we use autocorrelation functions to maximise the structure of 11 pulses detected with the MeerKAT radio telescope. The study is motivated by the low time-resolution of MeerKAT data, which presents a challenge to more traditional techniques. The burst profiles that are unveiled offer unique insight into the local environment of the FRB, including a possible deviation from the expected cold plasma dispersion relationship. The pulse features and their possible physical mechanisms are critically discussed in a bid to uncover the nature and origin of these transients
Nonsalmonid versus salmonid passage at nature-like and pool-and-weir fishways in Atlantic Canada, with special attention to rainbow smelt
No full textIntegrated modelling for economic valuation of the role of forests and woodlands in drinking water provision to two African cities
No full textThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Rapidly growing economies often have high population growth, resulting in agricultural expansion in rural areas and increased water demand in urban areas. Conversion of forests and woodlands to agriculture may threaten safe and reliable water supply in cities. This study assesses the regulating functions and economic values of forests and woodlands in meeting the water needs of two major cities in Tanzania and proposes an integrated modelling approach with a scenario-based analysis to estimate costs of water supply avoided by forest conservation. We use the process-based hydrological Soil and Water Assessment Tool (SWAT) to simulate the role of woody habitats in the regulation of hydrological flow and sediment control. We find that the forests and woodlands play a significant role in regulating sediment load in rivers and reducing peak flows, with implications for the water supply from the Ruvu River to Dar es Salaam and Morogoro. A cost-based value assessment under water treatment works conditions up to 2016 suggests that water supply failure due to deforestation would cost Dar es Salaam USD 4.6-17.6 million per year and Morogoro USD 308 thousand per year. Stronger enforcement of forest and woodland protection in Tanzania must balance water policy objectives and food security.This work formed part of the Valuing the Arc programme, which was supported by the Leverhulme
Trust (UK) and the Packard Foundation (USA). Additional funding was provided by the Eastern Arc
Mountains Conservation Endowment Fund (EAMCEF)
Fishway Effectiveness and Upstream Residency of Three Fish Species at Four Fishways in Prince Edward Island, Canada
No full textWe evaluated passage of Osmerus mordax (Rainbow Smelt), Salvelinus fontinalis (Brook Trout), and Alosa pseudoharengus (Alewife) at 4 fishways on Prince Edward Island, Canada. We implanted fish with passive integrated transponder (PIT) tags and recorded their movements using stationary PIT antennas. Passage at different fishway types was highly variable. Nature-like fishways passed over 96% of Brook Trout and a maximum of 41.8% of Rainbow Smelt. The latter percentage is the highest yet reported in the literature for Rainbow Smelt. Pool-and-weir fishways passed nearly 100% of Brook Trout, 13.2% of Rainbow Smelt, and only 5.6% of Alewife. After passing a fishway, upstream residency was highly variable both among species as well as among individuals within species. Rainbow Smelt were observed spawning within nature-like fishways, suggesting that this type of fishway may also provide spawning habitat. Results highlight the challenge of passing non-salmonid species and indicate nature-like fishways are more appropriate than technical designs for passing Rainbow Smelt
The impacts of short break provision on disabled children and families: an international literature review
No full textFor over 30 years, short breaks have been part of the landscape of support provision for families with a disabled child. Historically, the term ‘respite care’ has been used in much of the research literature concerning short breaks for families with a disabled child. However, ‘short breaks’ has become the preferred term, partly due to the negative connotations of family carers requiring ‘respite’ from their children, and partly because short breaks now encompass a much wider range of supports than out-of-home placement in specialist residential facilities (Cramer and Carlin, 2008). As such, the term ‘short breaks’ will be used throughout this review, with the exception of direct quotes from research studies where the term ‘respite’ is used by study participants or study authors
Structural studies of mixed zirconium (IV)-chromium (III) basic sulfates and other compounds
No full textThis thesis was scanned from the print manuscript for digital preservation and is copyright the author.
Researchers can access this thesis by asking their local university, institution or public library to
make a request on their behalf. Monash staff and postgraduate students can use the link in the References field
History of Dialysis in the UK: c. 1950–1980
No full textDialysis, the first technological substitution for organ function, is significant not only for the numbers of patients who have benefited. It contributed to the emergence of the field of medical ethics and the development of the nurse specialist, and transformed the relationship between physicians and patients by allowing patients to control their treatment.
This seminar drew on participants’ recollections of dialysis from the early, practically experimental days after the Second World War, when resources for research were scant, until the 1980s when it had become an established treatment. Pioneers from the first UK dialysis units recalled the creation of the specialty of nephrology amid discouragement from renal physicians and the MRC, which felt that the artificial kidney was a gadget that would not last.
International and interdisciplinary collaborations, and interactions between with industry and clinics in developing and utilising the specialist technology were emphasized. Patients, carers, nurses, technicians and doctors reminisced about their experiences of home dialysis, its complications and impact on family life, as well as the physical effects of surviving on long-term dialysis before transplantation became routine.
The meeting was suggested and chaired by Dr John Turney and witnesses include Dr Rosemarie Baillod, Professor Christopher Blagg, Professor Stewart Cameron, Mr Eric Collins, Professor Robin Eady, Mrs Diana Garratt, Professor David Kerr, Professor Sir Netar Mallick, Dr Frank Marsh, Dr Jean Northover, Dr Chisholm Ogg, Dr Margaret Platts, Dr Stanley Rosen and Professor Stanley Shaldon. Two appendices contain reminiscences from Professor Kenneth Lowe and Sir Graham Bull
A low cost virtual reality system for home based rehabilitation of the arm following stroke: a randomised controlled feasibility trial
No full textAuthor preprint and postprint available.OBJECTIVE: To assess the feasibility of conducting a randomised controlled trial of a home-based virtual reality system for rehabilitation of the arm following stroke. DESIGN: Two group feasibility randomised controlled trial of intervention versus usual care. SETTING: Patients' homes. PARTICIPANTS: Patients aged 18 or over, with residual arm dysfunction following stroke and no longer receiving any other intensive rehabilitation. INTERVENTIONS: Eight weeks' use of a low cost home-based virtual reality system employing infra-red capture to translate the position of the hand into game play or usual care. MAIN MEASURES: The primary objective was to collect information on the feasibility of a trial, including recruitment, collection of outcome measures and staff support required. Patients were assessed at three time points using the Wolf Motor Function Test, Nine-Hole Peg Test, Motor Activity Log and Nottingham Extended Activities of Daily Living. RESULTS: Over 15 months only 47 people were referred to the team. Twenty seven were randomised and 18 (67%) of those completed final outcome measures. Sample size calculation based on data from the Wolf Motor Function Test indicated a requirement for 38 per group. There was a significantly greater change from baseline in the intervention group on midpoint Wolf Grip strength and two subscales of the final Motor Activity Log. Training in the use of the equipment took a median of 230 minutes per patient. CONCLUSIONS: To achieve the required sample size, a definitive home-based trial would require additional strategies to boost recruitment rates and adequate resources for patient support
- …
