Geochemical and isotopic characteristics of palaeo-hydrothermal fluids related to granite magmatism, S W England

An assessment of stepped heating procedures for the extraction and isolation of carbonaceous species from fluid inclusions resulted in the development of low-blank procedures which permitted δ13C characterisation of palӕofluid CO2 (down to nanomole quantities) with an accuracy approaching that of the corresponding analytical precision. Similar procedures were successfully applied to the δ15N measurement of palӕofluid nitrogen at the sub-nanomole level. An investigation into the origin of fluids which characterised the earliest episodes of palӕohydrothermal activity associated with the granites of S W England indicates that the abundance of trace carbon species (CO2 , CH4 ) and nitrogen in the fluids was correlated with the metasedimentary contribution to the respective granite source. Furthermore, δ15N and δ13C data (obtained on fluid components and local Palӕozoic metasediments, in conjunction with published δ15N values of Cornubian granites), indicate that carbon and nitrogen in the hydrothermal systems were derived from the granite magmas. The chemical composition of the early hydrothermal fluids, together with geochemical and isotopic constraints from the characterisation of Palӕozoic metasedimentary country rocks, support the view that the fluids were genetically associated with the granites. Fluid interaction with the local metasedimentary rocks at a high level crustal appears to have been very limited. The incorporation of sedimentary matter into granitic protoliths during anatexis, with subsequent transfer to an exsolved hydrous phase during pluton cooling, is the most probable route by which palӕofluid solutes entered the early hydrothermal systems. Hydrogen stable isotope data, measured on the extracted palӕowaters, indicate that meteoric water was not a significant component of early hydrothermal systems associated with either the Dartmoor granite or the nearby Hemerdon Ball intrusive, if sub-solidus isotopic exchange was significant. In contrast, comparable data from early fluids associated with other component intrusives of the batholith (as characterised by W ± Sn oxide paragenesis) are consistent with the progressive dilution of a magmatic-hydrothermal component by local groundwaters

Solution-generating transformations in duality-invariant theories and the fluid/gravity correspondence

We explore dualities and solution-generating transformations in various contexts. Our focus is on the T-duality invariant form of supergravity known as double fi eld theory, the SL(5)-invariant M-theory extended geometry, and metrics dual under the fluid/gravity correspondence to an incompressible Navier-Stokes fluid. In double fi eld theory (DFT), a wave solution is shown to embed both the F1 string and the pp-wave. For the former, the Goldstone mode dynamics reproduce the duality symmetric string introduced by Tseytlin. We consider solution-generating techniques in DFT in the presence of an isometry, firstly via Buscher-like transformations in the DFT string -model, and secondly via the DFT equations of motion. In the SL(5)-invariant geometry, we provide a chain rule derivation of the covariant equations of motion, and present a wave solution embedding the M2 brane. Lastly, solution-generating transformations for metrics with an isometry are considered in the context of the fluid/gravity correspondence. Our focus is on the vacuum Rindler metric dual to a codimension one Navier- Stokes fluid. In particular, when there is a radially directed Killing vector, the dual fluid is found to exhibit an energy scaling invariance valid to all orders in the hydrodynamic expansionThis PhD thesis has been financially supported by an STFC grant

The establishment of the north-west frontier of Afghanistan, 1884-1888

The thesis is the story of the formation of a frontier which was needed by three interested parties: the new Amir of Afghanistan, Abdurrahman, who needed it because he felt within himself the power to weld Afghanistan into a united whole: the Russians, who, excluding some of their more chauvinist men of war, needed it to set a limit to their sprawling, huge, under-manned and moneyconsuming empire in Central Asia: and the English, who needed it to set an internationally agreed-upon frontier as a barrier to this same Russian advance, which had been seen by many throughout the century as a potential threat to British India

Prevalence and risk factors of diabetes and impaired fasting glucose in Nauru

<p>Abstract</p> <p>Background</p> <p>No comprehensive assessment of diabetes prevalence in Nauru has been conducted since an extreme prevalence was documented more than two decades ago. This study aims to determine the prevalence and risk factors of diabetes and impaired fasting glucose.</p> <p>Methods</p> <p>A nationwide survey in 2004 of people aged 15- 64 years (n = 1592). Fasting plasma glucose levels were used to defined diabetes (≥7.0 mmol/l or 126 mg/dl) and prediabetes (6.1-6.9 mmol/l or 110-125 mg/dl).</p> <p>Results</p> <p>The sex-standardized prevalence of diabetes was 13.0% (95% CI: 10.6, 15.4) in men, 14.4% (11.9, 16.9) in women, and 13.7% (12.0, 15.4) combined. The sex-standardized prevalence of prediabetes was 6.4% (4.6, 8.2) for men, 5.5% (3.9, 7.2) for women, and 6.0% (4.8, 7.3) combined. The prevalence of diabetes for individuals 15-24, 25-34, 35-44, 45-54 and 55-64 years was 4.5%, 7.6%, 24.1%, 32.9%, and 42.7%, respectively. The prevalence of prediabetes for the same age categories was 4.2%, 8.8%, 5.9%, 6.6%, 7.1%, respectively. Multivariable, multinomial logit modeling found risk factors for prediabetes were high cholesterol levels (OR: 2.02, 95% CI: 1.66, 2.47) and elevated waist circumference (OR: 1.04, 95% CI: 1.00, 1.08), and for diabetes were age in years (OR: 1.06; 95% CI: 1.04, 1.07), cholesterol levels (OR: 1.84, 95% CI: 1.58, 2.14) and waist circumference (OR: 1.04, 95% CI: 1.02, 1.07).</p> <p>Conclusions</p> <p>Diabetes remains a major public health problem in Nauru, affecting one out of every ten people. While the prevalence of diabetes has declined, its burden has persisted among the old but also extended towards the younger age groups.</p

The adverse neuro-developmental effects of postnatal steroids in the preterm infant: a systematic review of RCTs

BACKGROUND: Recent reports have raised concerns that postnatal steroids may cause neuro-developmental impairment in preterm infants. This systematic review was performed with the objective of determining whether glucocorticoid therapy, to prevent or treat bronchopulmonary dysplasia, impairs neuro-developmental outcomes in preterm infants. METHOD: A systematic review of the literature was performed. Medline was searched and articles retrieved using predefined criteria. Data from randomized controlled trials with adequate neuro-developmental follow up (to at least one year) were entered into a meta-analysis to determine the effects of postnatal treatment of preterm infants with glucocorticoids. Cerebral palsy rates, and neuro-developmental impairment (developmental score more than 2SD below the mean, or cerebral palsy or blindness) were analyzed. The studies were divided into 2 groups according to the extent of contamination of the results by treatment of controls with steroids after the initial study period, those with less than 30% contamination, and those with more than 30% contamination or size of contamination not reported. RESULTS: Postnatal steroid therapy is associated with an increase in cerebral palsy and neuro-developmental impairment. The studies with less contamination show a greater effect of the steroids, consistent with a real direct toxic effect of steroids on the developing central nervous system. The typical relative risk for the development of cerebral palsy derived from studies with less than 30% contamination is 2.86 (95% CI 1.95, 4.19). The typical relative risk for the development of neuro-developmental disability among followed up infants from studies with less than 30% contamination is 1.66 (95% CI 1.26, 2.19). From this subgroup of studies, the number of premature infants who need to be treated to have one more infant with cerebral palsy (number needed to harm, NNH) is 7; to have one more infant with neuro-developmental impairment the NNH is 11. CONCLUSIONS: Postnatal pharmacologic steroid treatment for prevention or treatment of bronchopulmonary dysplasia is associated with dramatic increases in neuro-developmental impairment. As there is no clear evidence in the literature of long term benefit, their use for this indication should be abandoned

The impact of early emergency department allied health intervention on admission rates in older people: a non-randomized clinical study

<p>Abstract</p> <p>Background</p> <p>This study sought to determine whether early allied health intervention by a dedicated Emergency Department (ED) based team, occurring before or in parallel with medical assessment, reduces hospital admission rates amongst older patients presenting with one of ten index problems.</p> <p>Methods</p> <p>A prospective non-randomized trial in patients aged sixty five and over, conducted in two Australian hospital EDs. Intervention group patients, receiving early comprehensive allied health input, were compared to patients that received no allied health assessment. Propensity score matching was used to compare the two groups due to the non-randomized nature of the study. The primary outcome was admission to an inpatient hospital bed from the ED.</p> <p>Results</p> <p>Of five thousand two hundred and sixty five patients in the trial, 3165 were in the intervention group. The admission rate in the intervention group was 72.0% compared to 74.4% in the control group. Using propensity score probabilities of being assigned to either group in a conditional logistic regression model, this difference was of borderline statistical significance (<it>p </it>= 0.046, OR 0.88 (0.76-1.00)). On subgroup analysis the admission rate in patients with musculoskeletal symptoms and angina pectoris was less for those who received allied health intervention versus those who did not. This difference was significant.</p> <p>Conclusions</p> <p>Early allied health intervention in the ED has a significant but modest impact on admission rates in older patients. The effect appears to be limited to a small number of common presenting problems.</p

Factors Associated with Height Catch-Up and Catch-Down Growth Among Schoolchildren

In developed countries, children with intrauterine growth restriction (IUGR) or born preterm (PT) tend to achieve catch-up growth. There is little information about height catch-up in developing countries and about height catch-down in both developed and developing countries. We studied the effect of IUGR and PT birth on height catch-up and catch-down growth of children from two cohorts of liveborn singletons. Data from 1,463 children was collected at birth and at school age in Ribeirão Preto (RP), a more developed city, and in São Luís (SL), a less developed city. A change in z-score between schoolchild height z-score and birth length z-score≥0.67 was considered catch-up; a change in z-score≤−0.67 indicated catch-down growth. The explanatory variables were: appropriate weight for gestational age/PT birth in four categories: term children without IUGR (normal), IUGR only (term with IUGR), PT only (preterm without IUGR) and preterm with IUGR; infant's sex; maternal parity, age, schooling and marital status; occupation of family head; family income and neonatal ponderal index (PI). The risk ratio for catch-up and catch-down was estimated by multinomial logistic regression for each city. In RP, preterms without IUGR (RR = 4.13) and thin children (PI<10th percentile, RR = 14.39) had a higher risk of catch-down; catch-up was higher among terms with IUGR (RR = 5.53), preterms with IUGR (RR = 5.36) and children born to primiparous mothers (RR = 1.83). In SL, catch-down was higher among preterms without IUGR (RR = 5.19), girls (RR = 1.52) and children from low-income families (RR = 2.74); the lowest risk of catch-down (RR = 0.27) and the highest risk of catch-up (RR = 3.77) were observed among terms with IUGR. In both cities, terms with IUGR presented height catch-up growth whereas preterms with IUGR only had height catch-up growth in the more affluent setting. Preterms without IUGR presented height catch-down growth, suggesting that a better socioeconomic situation facilitates height catch-up and prevents height catch-down growth