Heat transfer in active volcanoes: models of crater lake systems

Heat transfer in active volcanoes was investigated in this thesis. A general model of a crater lake system was developed that takes inputs of lake temperature, volume, chemical content, and meteorological conditions, and outputs the mass, energy, and chemical flows to and from the lake. The model was applied to lakes at Poás (Costa Rica) and Ruapehu (New Zealand), yielding volcanic power outputs of ~102-103 MW, and heat fluxes of ~102-104 W m-2. Heat is added to the lakes by hot brine and steam, derived from lake seepage and magmatic gas. The heat source is magma crystallising, cooling, and degassing. Background heat inputs are maintained by hydrothermal infiltration of magma, releasing latent and specific heat. Infiltration of the conductive boundary layer surrounding magma was modelled. The permeability created by contractive cooling was equated with the permeability required for two-phase convection to transport heat away from the boundary. Infiltration rates of ~1-100 m a-1 (metres/year), into conductive layers ~30-0.3 m thick, creating permeabilities of ~10-10-10-14m2, will provide the required heat flux. Cracking temperatures of magma depend upon infiltration rate, ranging from hydrothermal system temperatures at slow rates, to magma temperatures at the fastest rates. Predicted maximum rates are ~300 m a-1 for near-surface magma, and ~800 m a-1 for magma at ~1-3 km depth. Measured SO2 fluxes at Poás, and calculated influxes of HC1 to both lakes imply that degassed magma volumes (~0.004-0.08 km3 a-1) are much larger than likely intrusions. A new model was developed of small, vesiculating intrusions that circulate magma due to the density increase associated with gas loss. Dense, degassed magma descends, whilst buoyant, volatile-rich magma rises from a deep source. Pipe-like intrusions of radius ~5 m, tapping magma volumes >-0.05 km3, can produce the gas fluxes needed. Intrusions of this type probably occurred in 1980/81 and 1986 at Pods, and in 1968,1971,1975,1977,1981 and 1985 at Ruapehu, and were followed by intermittent eruptions and degassing. This degassing mechanism probably occurs at many volcanoes where high gas fluxes are observed, but no evidence exists for large, shallow intrusions. A model of compressible fluid flow in a rough fumarole conduit, with conductive heat loss to the surroundings, allows fumarole temperatures to be used to estimate the depth of their magma source. This also indicates shallow magma was emplaced at Poás in 1980/81 and 1986. In summary, heat transfer is achieved by a combination of intermittent gas release from minor shallow intrusions, together with infiltration of deeper magma. Infiltration is one mechanism for providing fractures allowing the release of gas from shallow intrusions, and circulation probably ceases due to freezing caused by infiltration

Exercise-induced tendon and bone injury in recreational runners: A test-retest reliability study

Background: Long-distance runners are prone to injuries including Achilles tendinopathy and medial tibial stress syndrome. We have developed an Internet comprehensive self-report questionnaire examining the medical history, injury history, and running habits of adult recreational runners. Objective: The objective of the study was to evaluate two alternative forms of test-retest reliability of a comprehensive self-report Internet questionnaire retrospectively examining the medical history, injury history, and running habits among a sample of adult recreational runners. This will contribute to the broad aims of a wider study investigating genetics and running injury. Methods: Invitations to complete an Internet questionnaire were sent by email to a convenience pilot population (test group 1). Inclusion criteria required participants to be a recreational runner age 18 or over, who ran over 15 km per week on a consistent basis. The survey questions addressed regular running habits and any injuries (including signs, symptoms, and diagnosis) of the lower limbs that resulted in discontinuation of running for a period of 2 consecutive weeks or more, within the last 2 years. Questions also addressed general health, age, sex, height, weight, and ethnic background. Participants were then asked to repeat the survey using the Internet platform again after 10-14 days. Following analysis of test group 1, we soft-launched the survey to a larger population (test group 2), through a local running club of 900 members via email platform. The same inclusion criteria applied, however, participants were asked to complete a repeat of the survey by telephone interview after 7-10 days. Selected key questions, important to clarify inclusion or exclusion from the wider genetics study, were selected to evaluate test-retest reliability. Reliability was quantified using the kappa coefficient for categorical data. Results: In response to the invitation, 28 participants accessed the survey from test group 1, 23 completed the Internet survey on the first occasion, and 20 completed the Internet retest within 10-21 days. Test-retest reliability scored moderate to almost perfect (kappa=.41 to .99) for 19/19 of the key questions analyzed. Following the invitation, 122 participants accessed the survey from test group 2, 101 completed the Internet survey on the first occasion, and 50 were randomly selected and contacted by email inviting them to repeat the survey by telephone interview. There were 33 participants that consented to the telephone interview and 30 completed the questionnaire within 7-10 days. Test-retest reliability scored moderate to almost perfect for 18/19 (kappa=.41 to .99) and slight for 1/19 of the key questions analyzed. Conclusions: We successfully developed a self-reported, retrospective questionnaire, delivered using Internet software, providing stable and reliable answers. We demonstrate that our survey provides a relatively quick, easy to complete, and cost effective method to collect epidemiological data from recreational runners and evaluate these participants for inclusion into a genetic study

Modified Early Warning Scores (MEWS) to support ambulance clinicians’ decisions to transport or treat at home

Introduction Modified Early Warning Scores (MEWS), calculated from patients’ vital signs, are used in hospital to identify patients who may benefit from admission or intensive care: higher MEWS indicates greater clinical risk. We aimed to evaluate MEWS to support paramedics’ decisions to transport patients to hospital or treat and leave them at home. Methods We used an interrupted time series design. We trained 19 volunteer paramedics to use MEWS to support decisions to transport or treat and leave at home. We used linear regression to evaluate differences in weekly transportation rates (percentage of patients attended and transported to hospital) and revisit rates (percentage of patients attended, treated at home and subsequently revisited within 7 days), comparing trends in rates 17 weeks prior (pre-MEWS) and 17 weeks post implementation of MEWS. Auto-calculated scores retrospectively applied to all data provided pre-MEWS and were compared with paramedic calculated scores post-MEWS. Results Of the 4140 patients attended, 2208 were excluded owing to missing values (n=1897), recording errors (n=21) or excluded clinical complaints (n=290). From the remaining data (n=1932) there were no significant differences in transportation rates (pre=55±6%; post=63±11%) by catering for the existing increasing trends where the confidence intervals of the regression slopes overlap (pre=0.15; 95%CI -0.51 to 0.80 vs. post=0.54; -0.58 to 1.65). Similarly, there were no significant difference in revisit rates (pre=4±4%; post=2±4%) catering for the similar trends (pre=-0.13; -0.53 to 0.27 vs. post=0.08; -0.33 to 0.49). Paramedic scores were incorrect 39% of the time (n=622). Conclusion MEWS had a minimal effect on transportation or revisit rates. Scores were frequently not calculated or recorded, or incorrectly calculated. Opportunities for ongoing training, clinical support and feedback were limited. A larger study, ensuring adequate ongoing support, is recommended before implementing MEWS on a wider scale

Polarization Modeling and Predictions for DKIST Part 2: Application of the Berreman Calculus to Spectral Polarization Fringes of Beamsplitters and Crystal Retarders

We outline polarization fringe predictions derived from a new application of the Berreman calculus for the Daniel K. Inouye Solar Telescope (DKIST) retarder optics. The DKIST retarder baseline design used 6 crystals, single-layer anti-reflection coatings, thick cover windows and oil between all optical interfaces. This new tool estimates polarization fringes and optic Mueller matrices as functions of all optical design choices. The amplitude and period of polarized fringes under design changes, manufacturing errors, tolerances and several physical factors can now be estimated. This tool compares well with observations of fringes for data collected with the SPINOR spectropolarimeter at the Dunn Solar Telescope using bi-crystalline achromatic retarders as well as laboratory tests. With this new tool, we show impacts of design decisions on polarization fringes as impacted by anti-reflection coatings, oil refractive indices, cover window presence and part thicknesses. This tool helped DKIST decide to remove retarder cover windows and also recommends reconsideration of coating strategies for DKIST. We anticipate this tool to be essential in designing future retarders for mitigation of polarization and intensity fringe errors in other high spectral resolution astronomical systems.Comment: Accepted for publication in JATI

Clifford Algebra Decompositions of Conformal Orthogonal Group Elements

Beginning with a finite-dimensional vector space V equipped with a nondegenerate quadratic form Q, we consider the decompositions of elements of the conformal orthogonal group COQ(V), defined as the direct product of the orthogonal group OQ(V) with dilations. Utilizing the correspondence between conformal orthogonal group elements and ``decomposable\u27\u27 elements of the associated Clifford algebra, ClQ(V), a decomposition algorithm is developed. Preliminary results on complexity reductions that can be realized passing from additive to multiplicative representations of invertible elements are also presented with examples. The approach here is based on group actions in the conformal orthogonal group. Algorithms are implemented in Mathematica using the CliffMath package

A novel human glucocorticoid receptor SNP results in increased transactivation potential.

Glucocorticoids are one of the most widely used therapeutics in the treatment of a variety of inflammatory disorders. However, it is known that there are variable patient responses to glucocorticoid treatment; there are responders and non-responders, or those that need higher dosages. Polymorphisms in the glucocorticoid receptor (GR) have been implicated in this variability. In this study, ninety-seven volunteers were surveyed for polymorphisms in the human GR-alpha (hGRα), the accepted biologically active reference isoform. One isoform identified in our survey, named hGR DL-2, had four single nucleotide polymorphisms (SNPs), one synonymous and three non-synonymous, and a four base pair deletion resulting in a frame shift and early termination to produce a 743 amino acid putative protein. hGR DL-2 had a decrease in transactivation potential of more than 90%. Upon further analysis of the individual SNPs and deletion, one SNP, A829G, which results in a lysine to glutamic acid amino acid change at position 277, was found to increase the transactivation potential of hGR more than eight times the full-length reference. Furthermore, the hGRα-A829G isoform had a differential hyperactive response to various exogenous steroids. Increasing our knowledge as to how various SNPs affect hGR activity may help in understanding the unpredictable patient response to steroid treatment, and is a step towards personalizing patient care

Selenate-enriched urea granules are a highly effective fertilizer for selenium biofortification of paddy rice grain

Citation: Premarathna, Lakmalie, Mike J. McLaughlin, Jason K. Kirby, Ganga M. Hettiarachchi, Samuel Stacey, and David J. Chittleborough. “Selenate-Enriched Urea Granules Are a Highly Effective Fertilizer for Selenium Biofortification of Paddy Rice Grain.” Journal of Agricultural and Food Chemistry 60, no. 23 (June 13, 2012): 6037–44. https://doi.org/10.1021/jf3005788.We examined the effects of applied selenium (Se) species, time of application, method of application and soil water management regime on accumulation of Se in rice plants. Plants were grown to maturity in a temperature- and humidity-controlled growth chamber using three water management methods: field capacity (FC), submerged until harvest, and submerged and drained two weeks before harvest; two Se species: selenate (SeO[subscript 4] ˉ²) and selenite (SeO[subscript 3]ˉ²) applied at a rate equivalent to 30 g haˉ¹; and four application methods: i) Se applied at soil preparation, ii) Se-enriched urea granules applied to floodwater at heading iii) foliar Se applied at heading and iv) fluid fertilizer Se applied to soil or floodwater at heading. Total Se concentrations in rice grains, husks, leaves, culms and roots were measured, as well as Se speciation in grains from the Se-enriched urea granule treatment. Highest Se concentrations in the grain occurred with SeO[subscript 4] ˉ² and with fertilizer applied at heading stage; SeO[subscript 4]ˉ²-enriched urea granules applied at heading increased grain Se concentrations 5 to 6 fold (by 450-600 μg kgˉ¹) compared to the control (no fertilizer Se applied) in all water treatments. Under paddy conditions other Se fertilization strategies were much less effective. Drainage before harvesting caused Se to accumulate in/on rice roots, possibly through adsorption onto iron plaque on roots. Rice grains contained Se mainly in the organic form as selenomethionine (SeM) which comprised over 90 % of the total grain Se in treatments fertilized with SeO[subscript 4]ˉ² -enriched urea granules. The results of this study clearly show of the fertilizer strategies tested that biofortification of Se in rice grains can best be achieved in lowland rice by broadcast application of SeO[subscript 4]ˉ² -enriched urea granules to floodwater at heading stage