Pentose phosphate pathway metabolism and glutathione in the host mucosal response to Helicobacter pylori infection

Recent studies have suggested a major role of reactive oxygen species (ROS) in the mediation of Helicobacter pylori associated disease. Hence, the severity of mucosal damage during such infection is likely to be dependent on the ability of mucosal cells to counteract the ROS load. The aim of this thesis was to investigate both the activity of the oxidative pentose pathway of glucose metabolism, and glutathione levels in the host response to Helicobacter pylori infection in both a mouse model and in adult symptomatic patrents.Thesis (M.Sc.) -- University of Adelaide, Dept. of Physiology, 2002

Museum, design, organisation: an exploration of spatialities and a project in modelling museum design activity

There were three stages in the process of narrowing and focussing the project. Initially the aim was nothing less than a 'paradigm shift' - to reframe the Praxis of Science as 'Design' using the museum as a microcosmic context  in which the complexity of the condition of modernity/ postmodernity was amply reflected. This over-ambitious scheme narrowed at first to one of exploring the interdisciplinary problem of the multidimensionality of design. In this, incommensurability and theories of space have to be accommodated in a workable model, and the forms and transformations of the model have then to be 'proved' in a praxiological exposition. Finally, it has become clear that much of the detailed creative work implied in the previous formulation of the project is, to be realistic, of a  postdoctoral nature. Therefore, the Ph.D. problem has been focussed even further.The focus is on the development of a multidimensional expression of museum design in the form of a theoretical model and an appraisal of its implications for general theory in organization and design. This involves (1)  Background theory - a survey of concepts and theories in modelling, (2) Focal theory - a critique of existing notions of organization and Praxis in museums and in Design, (3) Model theory - the development and presentation of a  more adequate scheme, and (4) Contribution - the evaluation of its potential as a generalization.Background TheoryIn the first part of the programme it has been necessary to ask a specific question about Philosophy - does any  specific paradigm offer an adequate conceptual scheme and 'language' in which to work? And if not, what do  so-called post-Philosophical approaches - radical pragmatism, ironism - have to offer in terms of a workable  strategy, perhaps one that is recognizably `designerly' in approach.In addition the definition and clarification of a wide range of incommensurable notions of 'space' has had to be undertaken to be clear that the complexity with which design, in the generic sense, engages has a particular character which is quite distinct from that of disciplines such as Science, History, and Politics which are  traditionally inclined towards epochal paradigmatic solidarity and towards contingent epistemological coherence.  The designer is, arguably, more of a chameleon than is the scientist or the historian or the politician, more so even than are the novelist and the ethnographer whom Rorty cites as latterly more crucial figures.' This 'quixotic' aspect of the designer's position is crucial to any argument about personal integrity and social value: this enigmatic  journeyman and traveller follows a lonely path guided by emotional (instinctual) as much as by intellectual and practical imperatives.Focal TheoryThe second part of the programme has involved two operations: (1) a  critical investigation, in some detail, of the discourses of organization, design and museography/museology; and (2) an opening up of the intervals between them, that is, an exploration their three interfaces - organization- design; design-museum; and museum-organization. Model Theory By proposing a visible constellation of spatial concepts and exposing the tensions which characterize their  performativity, the second part of the programme is drawn towards the final part of the programme. In this the  adequacy of the proposed model is evaluated in terms of the specific context of the museum as an organizational  type - a creative-administrative nexus - and in terms of its potential value as a generalization. This latter point has  involved consideration of the possible `museal' quality of organization in general and a reappraisal of the values of  design above and beyond the institutionalized, professionally delineated and administered discipline of Design  practice.ContributionThe conclusions emphasize the difficulty of boundary crossing enterprizes such as this project. A considerable effort has gone into deferring the synthetic instinct that all theory tends, sooner or later, to exemplify. However, not just for the sake of form, I make clear some specific and critical points in relation to the 'new' space established by this investigation of museum-design-organization. The museum design discipline has good reason to expound a communication-led collaborative philosophy and to have the strength to develop its discourse in more  sophisticated intellectual circles.In general there is a central message that emerges from the museum-design-organization complex which in one sense bolsters the ironist/new pragmatist stance in engaged theory but also reminds us that to be engaged one  must develop skills and capacities that are independent of the logics of language, that are irrational and yet  invaluable.And in future the interdisciplinary (as distinct from the multidisciplinary) platform must speak its name and be  generous. If one is met with incomprehension, resistance, threat response, or out and out hostility one has failed to understand the nature of design. One does not wait to be invited in, neither does one go straight for the jugular.  One makes a home, a communal place, a common ground. One finds the hearth and kindles in it a new flame, a  new light. One arranges a meeting of minds prepared to enchant with and to be enchanted by new visions and  new stories. And one helps each soul along its journey with no more than a gentle nudge in a promising direction  in the certain knowledge that the whole process will need to be repeated tomorrow and that this will remain the  case for each tomorrow

Frame-Dragging Vortexes and Tidal Tendexes Attached to Colliding Black Holes: Visualizing the Curvature of Spacetime

When one splits spacetime into space plus time, the spacetime curvature (Weyl tensor) gets split into an "electric" part E_{jk} that describes tidal gravity and a "magnetic" part B_{jk} that describes differential dragging of inertial frames. We introduce tools for visualizing B_{jk} (frame-drag vortex lines, their vorticity, and vortexes) and E_{jk} (tidal tendex lines, their tendicity, and tendexes), and also visualizations of a black-hole horizon's (scalar) vorticity and tendicity. We use these tools to elucidate the nonlinear dynamics of curved spacetime in merging black-hole binaries.Comment: 4 pages, 5 figure

A habitat-use model to determine essential fish habitat for juvenile brown shrimp (Farfantepenaeus aztecus) in Galveston Bay, Texas

A density prediction model for juvenile brown shrimp (Farfantepenaeus aztecus) was developed by using three bottom types, five salinity zones, and four seasons to quantify patterns of habitat use in Galveston Bay, Texas. Sixteen years of quantitative density data were used. Bottom types were vegetated marsh edge, submerged aquatic vegetation, and shallow nonvegetated bottom. Multiple regression was used to develop density estimates, and the resultant formula was then coupled with a geographical information system (GIS) to provide a spatial mosaic (map) of predicted habitat use. Results indicated that juvenile brown shrimp (0.50. These results indicate that this model may have a broader geographic application and is a plausible approach in refining current EFH designations for all Gulf of Mexico estuaries with similar geomorphological and hydrological characteristics

Frame-Dragging Vortexes and Tidal Tendexes Attached to Colliding Black Holes: Visualizing the Curvature of Spacetime

When one splits spacetime into space plus time, the spacetime curvature (Weyl tensor) gets split into an "electric" part E_{jk} that describes tidal gravity and a "magnetic" part B_{jk} that describes differential dragging of inertial frames. We introduce tools for visualizing B_{jk} (frame-drag vortex lines, their vorticity, and vortexes) and E_{jk} (tidal tendex lines, their tendicity, and tendexes), and also visualizations of a black-hole horizon's (scalar) vorticity and tendicity. We use these tools to elucidate the nonlinear dynamics of curved spacetime in merging black-hole binaries.Comment: 4 pages, 5 figure

Visualizing Spacetime Curvature via Frame-Drag Vortexes and Tidal Tendexes I. General Theory and Weak-Gravity Applications

When one splits spacetime into space plus time, the Weyl curvature tensor (vacuum Riemann tensor) gets split into two spatial, symmetric, and trace-free (STF) tensors: (i) the Weyl tensor's so-called "electric" part or tidal field, and (ii) the Weyl tensor's so-called "magnetic" part or frame-drag field. Being STF, the tidal field and frame-drag field each have three orthogonal eigenvector fields which can be depicted by their integral curves. We call the integral curves of the tidal field's eigenvectors tendex lines, we call each tendex line's eigenvalue its tendicity, and we give the name tendex to a collection of tendex lines with large tendicity. The analogous quantities for the frame-drag field are vortex lines, their vorticities, and vortexes. We build up physical intuition into these concepts by applying them to a variety of weak-gravity phenomena: a spinning, gravitating point particle, two such particles side by side, a plane gravitational wave, a point particle with a dynamical current-quadrupole moment or dynamical mass-quadrupole moment, and a slow-motion binary system made of nonspinning point particles. [Abstract is abbreviated; full abstract also mentions additional results.]Comment: 25 pages, 20 figures, matches the published versio

Momentum flow in black-hole binaries: II. Numerical simulations of equal-mass, head-on mergers with antiparallel spins

Research on extracting science from binary-black-hole (BBH) simulations has often adopted a "scattering matrix" perspective: given the binary's initial parameters, what are the final hole's parameters and the emitted gravitational waveform? In contrast, we are using BBH simulations to explore the nonlinear dynamics of curved spacetime. Focusing on the head-on plunge, merger, and ringdown of a BBH with transverse, antiparallel spins, we explore numerically the momentum flow between the holes and the surrounding spacetime. We use the Landau-Lifshitz field-theory-in-flat-spacetime formulation of general relativity to define and compute the density of field energy and field momentum outside horizons and the energy and momentum contained within horizons, and we define the effective velocity of each apparent and event horizon as the ratio of its enclosed momentum to its enclosed mass-energy. We find surprisingly good agreement between the horizons' effective and coordinate velocities. To investigate the gauge dependence of our results, we compare pseudospectral and moving-puncture evolutions of physically similar initial data; although spectral and puncture simulations use different gauge conditions, we find remarkably good agreement for our results in these two cases. We also compare our simulations with the post-Newtonian trajectories and near-field energy-momentum. [Abstract abbreviated; full abstract also mentions additional results.]Comment: Submitted to Phys. Rev.

Onchocerciasis Control: Vision for the Future from a Ghanian perspective

Since 1987 onchocerciasis control has relied on the donation of ivermectin (Mectizan®, Merck & Co., Inc.) through the Mectizan Donation Programme. Recently, concern has been raised over the appearance of suboptimal responses to ivermectin in Ghana – highlighting the potential threat of the development of resistance to ivermectin. This report summarises a meeting held in Ghana to set the research agenda for future onchocerciasis control. The aim of this workshop was to define the research priorities for alternative drug and treatment regimes and control strategies to treat populations with existing evidence of suboptimal responsiveness and define research priorities for future control strategies in the event of the development of widespread ivermectin resistance

Monitoring the Morphology of M87* in 2009–2017 with the Event Horizon Telescope

The Event Horizon Telescope (EHT) has recently delivered the first resolved images of M87*, the supermassive black hole in the center of the M87 galaxy. These images were produced using 230 GHz observations performed in 2017 April. Additional observations are required to investigate the persistence of the primary image feature—a ring with azimuthal brightness asymmetry—and to quantify the image variability on event horizon scales. To address this need, we analyze M87* data collected with prototype EHT arrays in 2009, 2011, 2012, and 2013. While these observations do not contain enough information to produce images, they are sufficient to constrain simple geometric models. We develop a modeling approach based on the framework utilized for the 2017 EHT data analysis and validate our procedures using synthetic data. Applying the same approach to the observational data sets, we find the M87* morphology in 2009–2017 to be consistent with a persistent asymmetric ring of ~40 μas diameter. The position angle of the peak intensity varies in time. In particular, we find a significant difference between the position angle measured in 2013 and 2017. These variations are in broad agreement with predictions of a subset of general relativistic magnetohydrodynamic simulations. We show that quantifying the variability across multiple observational epochs has the potential to constrain the physical properties of the source, such as the accretion state or the black hole spin

First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

We present measurements of the properties of the central radio source in M87 using Event Horizon Telescope data obtained during the 2017 campaign. We develop and fit geometric crescent models (asymmetric rings with interior brightness depressions) using two independent sampling algorithms that consider distinct representations of the visibility data. We show that the crescent family of models is statistically preferred over other comparably complex geometric models that we explore. We calibrate the geometric model parameters using general relativistic magnetohydrodynamic (GRMHD) models of the emission region and estimate physical properties of the source. We further fit images generated from GRMHD models directly to the data. We compare the derived emission region and black hole parameters from these analyses with those recovered from reconstructed images. There is a remarkable consistency among all methods and data sets. We find that >50% of the total flux at arcsecond scales comes from near the horizon, and that the emission is dramatically suppressed interior to this region by a factor >10, providing direct evidence of the predicted shadow of a black hole. Across all methods, we measure a crescent diameter of 42 +/- 3 mu as and constrain its fractional width to b