Thermally Driven Hydromagnetic Dynamos

There are still many challenges to be overcome before we can claim to have a full understanding of the generation of the Earth's magnetic field. Prom a mathematical point of view, the governing equations are nonlinear and must be solved in fully three dimensions, meaning that a numerical method must be employed, although this would probably also be the case for a two-dimensional problem. However, it is only relatively recently that the computer technology has become available to make this possible. Obtaining these solutions remains a highly computationally intensive task, making it difficult to find solutions for a range of parameter values. This is extremely important as a great deal of uncertainty still surrounds the present (and past) geophysical values of the main parameters in the governing equations. Our aim is to try and further understanding of the effect of varying some of these key parameters in simplified, but fully self-consistent hydromagnetic dynamo models. These models will allow us to examine the effect of including the full inertial term to the equations, which has in the past been neglected due to the small geophysical value of the parameter which controls its effect. Further physical insight into the magnetic field generation mechanism will be provided, and we will examine some key issues in numerical dynamo modelling. A broad introduction to the Earth's magnetic field, the properties of the core, the possible energy sources and the current state of successful numerical dynamo models, is given in Chapter 1. In Chapter 2 we will describe in detail the governing equations and associated theory of magnetohydrodynamic (MHD) flows in a rapidly rotating spherical shell, as is appropriate for the Earth. Chapter 3 presents the results of varying the Rayleigh number, Ra, and the azimuthal wavenumber, m, for a 21/2D dynamo model, and also examines the effect (if any) of different forms of thermal driving. We show that the dynamo can exhibit very different types of behaviour for small changes in Ra, and in one particular case the magnetic field can be shut off, leaving only a convective solution. This type of behaviour is not observed for a different value of m. Our model is therefore too severely truncated in azimuth, but also suggests that care should be exercised when interpreting the results from a single run of a numerical dynamo model with a fixed value of Ra. The different forms of thermal driving produce qualitatively very similar dynamos, with the case of internal heating seeming to give the most efficient dynamo at any given value of Ra. However our definition of Ra is most suitable for internal heating, and this probably accounts for the difference in efficiency. In Chapter 4, the same 21/2D model is used to examine the effect of varying the inner core radius. This is the first detailed study to be performed in a fully self- consistent dynamo model, and will aid understanding of the long term behaviour of the geodynamo, because the inner core is slowly growing as it freezes out of the outer core fluid. We find that the critical Rayleigh number for the onset of convection is dependent on the inner core radius. This plays a crucial role in determining the behaviour of the solution, along with the geometry and the diffusion time of the inner core. We show that not only does a large inner core stabilise the magnetic field, due to the diffusion time of the inner core, but that a small inner core also stabilises the magnetic field, due to the simpler geometry. The inertial term has not been included in a 21/2D model before, although it is included in some form in most SD models. In Chapter 5, we use a different 21/2D model to examine the effect of including the inertial term, and choosing different values of the Rossby number, Ro, while keeping the Ekman number, E, fixed. In addition the imposed equatorial symmetry constraint has been removed in this new model. We find a rather complicated pattern of behaviour, with the inertia of the fluid strongly affecting the time dependence of the solution obtained, but having less effect on the structure on the flow. There are two possible solutions, one which is chaotic and one which is periodic. As the value of Ro is increased we find that it becomes increasingly difficult to maintain a magnetic field, and above a certain value of Ro no solutions could be obtained. A solution obtained with m = 4 intermittently changes between chaotic and periodic states

A quantitative analysis of the effectiveness of LOGO as an instructional aid for teaching mechanics in physics

BACKGROUND:Workplace bullying has diverse consequences at both the organisational and individual level. Anecdotal reports indicate that workplace bullying is an issue of particular concern for Australian FIFO workers, which may impact on psychosocial distress. However, no prior studies have examined this issue empirically in a FIFO worker cohort. METHODS AND MATERIALS:A cross-sectional survey study design was used to establish the prevalence of bullying in Australian FIFO, antecedents of bullying, and its association with psychosocial distress. Responses were received from 580 FIFO workers in the Australian resources sector. Primary outcome measures were Negative Acts Questionnaire-Revised, Beck Depression Inventory II, and Beck Hopelessness Scale. Logistic regression models were constructed to examine the association between bullying, suicide risk, and clinical depression. RESULTS:Over half of the respondents experienced workplace bullying (55.7%), and about one-third reported moderate or more severe depression (32.3%). Being above the median age (OR = 0.51; 95% CI = 0.31-0.83) and having a supervisor who failed to promote collaboration (OR = 3.04; 95% CI = 1.84-5.04) were both significantly associated with experiencing bullying. Bullying was associated with an almost threefold increase in the likelihood of participants reporting increased suicide risk (OR = 2.70; 95% CI = 1.53-4.76). Bullying was also associated with participants being almost two and a half times more likely to report clinical depression (OR = 2.38; 95% CI = 1.40-4.05). CONCLUSION:The incidence of bullying in Australian FIFO workers has reached alarming proportions. Bullying was significantly associated with higher levels of clinical depression and suicide risk. The results highlight the need to implement in the Australian resource sector interventions that reduce workplace bullying

Effects of glaucoma and snoring on cerebral oxygenation in the visual cortex: a study using functional Near Infrared Spectroscopy (fNIRS)

Purpose: The purpose of this study was to investigate the effects of snoring and glaucoma on the visual Haemodynamic Response (HDR) using functional Near Infrared Spectroscopy (fNIRS). Methods: We recruited 8 glaucoma patients (aged 56-79), 6 habitual snorers (aged 26-61) and 10 healthy control participants (aged 21-78). Glaucoma patients were of varying subtypes and under care of ophthalmologists. Prior to testing visual acuity, blood pressure, heart rate and a medical history were taken. HDRs were recorded over the primary visual cortex (V1) using a reversing checkerboard paradigm. Results & Discussion: All participants showed the characteristic increase of Oxyhaemoglobin concentration ([HbO]) and decrease of Deoxyhaemoglobin concentration ([HbR]) during visual stimulation (p < 0.001, η2 = 0.78). Despite this, there were signifi cant group differences with a large effect size (η2 = 0.28). During visual stimulation normal participants had greater [HbO] compared to snorers and glaucoma patients (p < 0.01). Both glaucoma patients and snorers presented with comparable HDR for [HbO] and [HbR] in V1. Importantly, during visual stimulation, the increased [HbO] in glaucoma patients correlated well with their visual fi elds and self-reported activities of daily living (r = -0.98, r = -0.82, p < 0.05). Both glaucoma patients and snorers presented with an attenuated HDR in V1. Our results suggest a possible vascular link between these conditions

⁹⁹ᵐTc SPECT imaging agent based on cFLFLFK for the detection of FPR1 in inflammation

Non-invasive imaging of the inflammatory process can provide a great deal of insight into a wide variety of diseases states, aiding diagnosis, evaluation and effective targeted treatment. During inflammation, blood borne leukocytes are recruited, through a series of activation and adhesion steps, to the site of injury or infection where they migrate across the blood vessel wall into the tissue. Thus, tracking leukocyte recruitment and accumulation provides a dynamic and localised read out of inflammatory events. Current leukocyte imaging techniques require ex vivo labelling of patient blood, involving laborious processing and potential risks to both patient and laboratory staff. Utilising high affinity ligands for leukocyte specific receptors may allow for injectable tracers that label leukocytes in situ, omitting potentially hazardous ex vivo handling. Formyl peptide receptors (FPRs) are a group of G-protein coupled receptors involved in the chemotaxis and inflammatory functioning of leukocytes. Highly expressed on leukocytes, and up regulated during inflammation, these receptors provide a potential target for imaging inflammatory events. Herein we present the synthesis and initial in vitro testing of a potential Single Photon Emission Computed Tomography (SPECT) leukocyte tracer. The FPR1 antagonist cFLFLFK-NH₂, which displays high affinity with little physiological effect, has been linked via a PEG motif to a ⁹⁹ᵐTc chelate. This tracer shows in vitro binding to human embryonic kidney cells expressing the FPR1 receptor, and functional in vitro tests reveal cFLFLFK-NH₂ compounds to have no effect on inflammatory cell functioning. Overall, these data show that ⁹⁹ᵐTc.cFLFLFK-NH₂ may be a useful tool for non-invasive imaging of leukocyte accumulation in inflammatory disease states

Sclerosing alcohol injections for the management of intermetatarsal neuromas: a systematic review

An intermetatarsal neuroma is a plantar digital neuritis causing metatarsalgia of the affected inter-metatarsal space. At present the evidence to support the management of the condition is poor with only some quality evidence supporting the short-term management of intermetatarsal neuromas using steroid injections. Some authors have supported the use of alcohol sclerosing intra-lesional injections to treat intermetatarsal neuromas. Following a search of the evidence 11 articles were identified. The systematic review found that alcohol injections appear to be safe although some papers report a short-term side effect of a flogistic reaction and there are variances in the alcohol concentration used and guiding verses not guiding the injection using ultrasound imaging. Some of the evidence may suggest a sclerosing histological effect of the nerve. However, all the studies reviewed present a research design offering a low level of evidence that is open to methodological biases and interpretation. Thus, this review found insufficient high-quality research evidence to afford conclusions on the management of intermetatarsal neuromas with alcohol sclerosing agent injections.sch_pod35pub5134pu

Marine fisheries and future ocean conflict

Conflict over marine fishery resources is a growing security concern. Experts expect that global changes in our climate, food systems and oceans may spark or exacerbate resource conflicts. An initial scan of 803 relevant papers and subsequent intensive review of 31 fisheries conflict studies, focused on subnational and international conflicts, suggests that four substantial scientific gaps need addressing to improve our understanding of the nature and drivers of fisheries conflict. First, fisheries conflict and levels of conflict intensity are not precisely defined. Second, complex adaptive systems thinking is underutilized but has the potential to produce more realistic causal models of fishery conflict. Third, comparative large‐scale data and suitably integrative methodologies are lacking, underscoring the need for a standardized and comparable database of fisheries conflict cases to aid extrapolation beyond single case‐studies. Fourth, there is room for a more widespread application of higher order concepts and associated terminology. Importantly, the four gaps highlight the homogenized nature of current methodological and theoretical approaches to understanding fishery conflict, which potentially presents us with an oversimplified understanding of these conflicts. A more nuanced understanding of the complex and dynamic nature of fishery conflict and its causes is not only scientifically critical, but increasingly relevant for policymakers and practitioners in this turbulent world

Identifying predictors of international fisheries conflict

Marine capture fishery resources are declining, and demand for them is rising. These trends are suspected to incite conflict, but their effects have not been quantitatively examined. We applied a multi-model ensemble approach to a global database of international fishery conflicts between 1974 and 2016 to test the supply-induced scarcity hypothesis (diminishing supplies of fishery resources increase fisheries conflict), the demand-induced scarcity hypothesis (rising demand for fishery resources increases fisheries conflict), and three alternative political and economic hypotheses. While no single indicator was able to fully explain international conflict over fishery resources, we found a positive relationship between increased conflict over fishery resources and higher levels of per capita GDP for the period 1975–1996. For the period 1997–2016, we found evidence supporting the demand-induced scarcity hypothesis, and the notion that an increase in supply of fishery resources is linked to an increase in conflict occurrence. By identifying significant predictors of international fisheries conflict, our analysis provides useful information for policy approaches for conflict anticipation and management

The 'main street' in Kirkwall: a pilot research projects.

In July 2010, researchers from Robert Gordon University, in collaboration with the University of Aberdeen, conducted a pilot research project which investigated the role of the main street (i.e. Bridge Street, Albert Street, Broad Street and Victoria Street) in sustaining cultural identity, community, and a sense of place in Kirkwall, and in Orkney more widely. This project built on previous research conducted by Robert Gordon University which examined journey making and travel behaviour in Kirkwall as part of a wider study looking at car culture in the town

Research is ‘a step into the unknown’: an exploration of pharmacists’ perceptions of factors impacting on research participation in the NHS

Objective This study explored National Health Service (NHS) pharmacists’ perceptions and experiences of pharmacist-led research in the workplace.  Design Semistructured, face-to-face discussions continued until distinct clusters of opinion characteristics formed. Verbatim transcripts of audio-recordings were subjected to framework analysis.  Setting Interviews were carried out with 54 pharmacists with diverse backgrounds and roles from general practices and secondary care in the UK's largest health authority.  Results The purpose and potential of health services research (HSR) was understood and acknowledged to be worthwhile by participants, but a combination of individual and system-related themes tended to make participation difficult, except when this was part of formal postgraduate education leading to a qualification. Lack of prioritisation was routinely cited as the greatest barrier, with motivation, confidence and competence as additional impediments. System-related themes included lack of practical support and pharmacy professional issues. A minority of highly motivated individuals managed to embed research participation into routine activity.  Conclusions Most pharmacists realised the desirability and necessity of research to underpin pharmacy service expansion, but a combination of individual and professional level changes is needed to increase activity. Our findings provide a starting point for better understanding the mindset of hospital-based and general practice-based pharmacists towards research, as well as their perceived barriers and supports

Dietary fibers inhibit obesity in mice, but host responses in the cecum and liver appear unrelated to fiber-specific changes in cecal bacterial taxonomic composition

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