Sediment deposition and preservation in Aeolian Systems: A comparison of contemporary and ancient ergs

Ancient and contemporary aeolian systems have been subject of important conceptual advances in recent years, however, a disconnect exists between the complexities inherent at the depositional surface and subsequent controls on preservation. At the fundamental level, the depositional environment consists of dune-fields, and the rock record is a stratigraphic architecture consisting of cross-strata and bounding surfaces. Vast outcrops of ancient aeolian strata display huge amounts of temporal variation manifest through dune-field evolution while the sedimentary record of contemporary ergs remain largely unknown. In order to bridge these gaps this research utilises a range of digitally based systems and techniques to analyse spatial data in order to unravel contemporary and ancient system evolutions. The study utilised the Wahiba Sand Sea of Oman and the Jurassic Navajo Sandstone of western USA as contemporary and ancient analogues respectively. Analysis of high to medium-resolution satellite and geophysical datasets demonstrate that antecedent topography has been a dominating allogenic boundary condition during the formation and growth of large linear bedforms in the Wahiba Erg. There appears to be a hierarchy of autogenic processes influenced by antecedent topography that imparts a uniqueness to the emergent dune-field pattern. The production of large-scale virtual outcrop models permitted broad spatial analysis of three sites across the Navajo Sandstone which represent marginal through central erg settings. Results show unique allogenic controls relating to system architectures at each outcrop, some of which provide validations to hypotheses made from observations within the contemporary analogue. The research demonstrates that in extracting signals of allogenic boundary conditions within which autogenic system processes evolved is the basis for the interpretation of geomorphic landforms and their stratigraphic record. The analogues represent a point on a spectrum of preservations styles recently detected in aeolian systems and provide additional examples with which to advance our knowledge

Data Analysis Techniques for Fan Performance in Highly-Distorted Flows from Boundary Layer Ingesting Inlets

The design of a unique distortion-tolerant fan for a high-bypass ratio boundary-layer ingesting propulsion system has been completed and a rig constructed and tested in the NASA Glenn 8x6 wind tunnel. Processing the data from the experiment presented some interesting challenges because of the complexity of the experimental setup and the flow through the test rig. The experiment was run in three phases, each of which employed a unique complement of inlet throat and fan face instrumentation to avoid the blockage that would have resulted from simultaneously installing all of the rakes. The measurement from the individual test points were subsequently combined to compute the overall stage performance. A CFD model of the experiment was used to gain understanding of the flow field and to test some of the techniques proposed for interpolating and extrapolating the measurements into regions where measurements were not made. This capability became extremely useful when it was discovered that there was an unexpected total temperature distortion in the tunnel. The CFD model was modified by inserting a total temperature profile at the upstream boundary that mimicked the measured distortion where measurements were available and that CFD solution was used to investigate methods to infer the complete total temperature field at the fan face

Scanning the horizon: emerging hospital-wide technologies and their impact on critical care

This commentary represents a selective survey of developments relevant to critical care. Selected themes include advances in point-of-care diagnostic testing, glucose control, novel microbiological diagnostics and infection control measures, and developments in information technology that have implications for intensive care. The latter encompasses an early example of an artificially intelligent clinical decision support mechanism, the introduction of a national health care information technology programme (UK NPfIT) and its implications, and exotic threats to patient safety due to emergent behaviour in complex information systems

Antibullying Interventions in Schools : Ingredients of Effective Programs

Because bullying is a serious problem in Canadian schools, antibullying programs have been widely implemented to redress the problem. School principals in Ontario (N=395) completed a questionnaire to document the severity of bullying, the amount of anti‐bullying resources, and the variety of antibullying activities in their schools. Results reveal that reductions in bullying in previous years, sufficiency of resources for resolving bullying, and amounts of antibullying programming were all positively associated antibullying program outcomes. These data suggest that the investment of time, effort, and money in school‐based antibullying initiatives can lead to safer and more peaceful schools environments. Key words: bullying, primary prevention, program evaluation Comme l’intimidation est un problème sérieux dans les écoles canadiennes, des programmes de lutte contre l’intimidation font leur apparition un peu partout. Des directeurs et directrices d’école en Ontario (N = 395) ont rempli un questionnaire visant à documenter la gravité du problème, les ressources existantes et les diverses activités anti‐intimidation mises en place dans les écoles. D’après les résultats du questionnaire, la réduction de l’intimidation au cours des années précédentes, la pertinence des ressources en place pour faire face aux incidents d’intimidation et le nombre de programmes de lutte contre l’intimidation étaient tous corrélés à l’amélioration des résultats en la matière. Ces données semblent indiquer que le temps, les efforts et les fonds investis dans les initiatives anti‐intimidation contribuent à créer un climat de paix et rendre les écoles plus sécuritaires. Mots clés : intimidation, prévention, évaluation de programmes.

A stratigraphic, petrographic and geochemical study of the gamagara formation at the maremane dome, Northern Cape province, South Africa

Between 80 and 90 percent of the potential iron ore reserves in the Griqualand West basin in the Northern Cape province of South Africa is situated in the Asbesheuwels Iron-formation immediately below an unconformity that separates it from the Gamagara Formation of the Olifantshoek Supergroup. This extensive regional unconformity marks a lengthy period of non-deposition and erosion which preceded the deposition of the Gamagara Formation. Due to the nature of the intimate relationship between the shales and iron ore body, specifically on the Maremane dome, new insights into the Gamagara Formation were required. The thesis provides a renewed stratigraphic, petrographic and geochemical study on the Gamagara Formation and relates it to previous studies done on the lateral correlative Mapedi Formation, some 70 km north of the Maremane dome. The use of 10 newly available drill-cores selected from across the Maremane Dome allows for regional correlations to be made in a study which employs petrographic/mineralogical investigations using transmitted/reflected light microscopy, XRD and EPMA, complimented by traditional whole-rock geochemical analysis of majors, traces, rare earth elements and Nd isotopes. At the base of the Gamagara lie conglomerates representing an alluvial fan deposit, overlying this, shale and quartzite successions represent progradational delta lobes. The deltas are interpreted to be tide- dominated as indicated by a combination of features including: microbial mat growth, intertidal deposition in the delta top, sand bars and flaser laminations in the upward coarsening quartzite units of the delta front. Transgression is indicated by periodic transgressive lag deposits. A variety of sedimentary structures and textural features are described that can be interpreted as the results of microbial mat colonization on the sediment surface. Although in none of the described features can it irrefutably be proven that they are microbial mat deposits, the observed features are consistent with such an interpretation and should be considered indicators of possible microbial mat presence in the Gamagara Formation. Hydrothermal modifications are identified in various units of the Gamagara Formation and seem to occur as separate events. Basal white shales show mobility of Al and slight HFSE enrichments, while overlying red shales record HFSE, K and Fe enrichments. K-metasomatism has been known to occur in the underlying paleoweathering profile of the Transvaal Supergroup (Ongeluk lavas) a unit which is interpreted as the most likely provenance for the mid-to-upper shale lithofacies of the Gamagara Formation. Highly alkaline F-bearing brines had the ability to mobilize titania and fluorapatite, reset Nd isotope systematics and ultimately enriched HFSE concentrations in the red shales of the Gamagara Formation. As the same enrichment is evident in the Mapedi Formation, the event possibly represents unconformity related fluid flow on a regional scale (~140 km). Nd-isotopes record an isotopic disturbance concurrent with the HFSE enrichment and Tdm model ages suggest disruption (and enrichment) occurred between 1.73 and 1.86 Ga. Following this, Fe-addition occurred by epigenetic mechanisms similar to those of MVT-type deposits. Although gaps in the current understanding of the modifications of the Gamagara Formation exist, such events may have far reaching implications for the underlying iron ore bodies and the possibility arises that the genesis and/or epigenetic modification of the ore bodies of the Transvaal Supergroup may be casually linked to the same fluid-migration event/s

Lithium, magnetic resonance and the human brain

PhD ThesisThis thesis explores the effects of lithium on the human brain using structural, functional and spectroscopic magnetic resonance techniques. Contemporary issues surrounding the pharmacological effects of lithium are investigated and aspects of its pharmacokinetics examined. Bipolar disorder is known to be associated with dysfunction of themonoaminergic neurotransmitter systems of the brain. It is proposed that the antimanic properties of lithium derive from its attenuation of the actions of dopamine. In a randomised, placebo-controlled study of lithium involving 24 healthymen, mania was modelled by the administration of methamphetamine. Sustained attention, known to be disturbed in mania, was assessed during functional magnetic resonance imaging. Within the lithium group, response times were slowed and the effects of methamphetamine on functional magnetic resonance imaging contrast diminished. These findings are discussed in the context of current theories and contrasted with existent data. Lithium has been reported to increase the volume of grey matter in the brain in numerous magnetic resonance imaging studies. This observation was replicated in a longitudinal, voxel-based morphometry study of 31 healthy men. Combining quantitative imaging with various structural analysis techniques, it is argued that the grey matter change may be better accounted for by lithium altering the relaxation characteristics of protons; that is to say, signal change not true volume expansion. The biophysical basis of this theory is discussed, together with its implications. The pharmacokinetic properties of lithium in man are incompletely characterised, in particular its distribution in various tissues of the brain. The development of a magnetic resonance spectroscopy tool is described; its purpose was to determine the concentration of lithium in grey and white matter in a time-scale suited to clinical practice. Lithium was found to be evenly distributed in the brain regions examined, with total acquisition times constrained to less than óþ minutes. The applications and future developments of in vivo lithium spectroscopy are considered. It is concluded that variousmagnetic resonance techniquesmay be usefully applied to the investigation of the interactions between lithium and the human brain.The Medical Research Council, Clinical Research Training Fellowship

Long-term respiratory outcomes following preterm birth

Preterm birth interrupts the normal development of the respiratory system. Taken together with the lung injury that can occur antenatally such as from chorioamnionitis or postnatally by interventions such as mechanical ventilation and oxygen therapy, survivors are at risk of developing long term deficits of their respiratory system. Decrements of lung spirometry have been regularly reported in those born preterm across all gestational ages. Those who develop chronic lung disease of prematurity (also called bronchopulmonary dysplasia) are the most affected, but lung function decrements are also seen in those born at later gestation of between 33 and 36 weeks, a population that generally does not require respiratory support in the neonatal period. Besides spirometry, many other techniques have been used to assess the status of the respiratory system including measurement of static lung volumes, airway resistance and compliance, bronchial hyperresponsiveness, diffusing capacity, exhaled nitric oxide and newer imaging techniques including hyperpolarised 3-helium magnetic resonance imaging. Discussed in this review are the findings from such methods to delineate the respiratory outcomes that occur after preterm birth

Locking plate fixation with and without inferomedial screws for proximal humeral fractures: a biomechanical study.

PURPOSE. To compare the efficacy of locking plate fixation with and without inferomedial screws in maintaining the reduction of a proximal humeral fracture. METHODS. 22 synthetic humerus models were used. A standardised 3-part proximal humeral fracture with a 4-mm wedge segment was created and fixed with a locking plate and screws with (n=11) and without (n=11) inferomedial screws. The intrafragmentary motion of the construct at 250, 500, 750, and 1000 cycles of 532 N loading, and the load to failure of the 2 groups were compared. RESULTS. Locking plate fixation with inferomedial screws reduced the mean intrafragmentary motion in all cycles (

The Star Formation Across Cosmic Time (SFACT) Survey. III. Spectroscopy of the Initial Catalog of Emission-Line Objects

The Star Formation Across Cosmic Time (SFACT) survey is a new narrowband survey designed to detect emission-line galaxies (ELGs) and quasi-stellar objects (QSOs) over a wide range of redshifts in discrete redshift windows. The survey utilizes the WIYN 3.5m telescope and the Hydra multifiber positioner to perform efficient follow-up spectroscopy on galaxies identified in the imaging part of the survey. Since the objects in the SFACT survey are selected by their strong emission lines, it is possible to obtain useful spectra for even the faintest of our sources (r ~ 25). Here we present the 453 objects that have spectroscopic data from the three SFACT pilot-study fields, 415 of which are confirmed ELGs. The methodology for processing and measuring these data is outlined in this paper and example spectra are displayed for each of the three primary emission lines used to detect objects in the survey (H-alpha, [O III]5007, and [O II]3727). Spectra of additional QSOs and non-primary emission-line detections are also shown as examples. The redshift distribution of the pilot-study sample is examined and the ELGs are placed in different emission-line diagnostic diagrams in order to distinguish the star-forming galaxies from the active galactic nuclei.Comment: 20 pages, 10 figures. Accepted for publication in the Astronomical Journa