Structural and physical processes in accretionary complexes: the role of fluids in convergent margin development

Accretionary complexes that form at subduction zones develop a spectrum of styles of deformation that range between coherent forms in which the processes of thrusting predominate and incoherent forms in which melanges, formed by such processes as mud diapirism, are the dominant constituent. This thesis examines processes that control the development of these accretionary styles by comparing geophysical observations of the modern Barbados Ridge accretionary complex, with ancient subaerially exposed examples in Sabah, N. Borneo and W. Timor.A structural and lineament map of the offshore regions of the Barbados Ridge complex has been constructed using GLORIA. Seabeam and seismic data. It reveals marked changes in the surface structure of the accretionary wedge, particularly where basement ridges associated with oceanic fracture zones underthrust it. It also documents the presence of large numbers, of mud diapirs in its southern regions. The mud diapirs appear to be associated with the accretion of thick sequences of turbidites and their distribution is proposed to relate to the subcretion or underplating of underconsolidated material to the base of the complex. Fieldwork in Sabah and Timor concentrated on describing features associated with currently active mud diapirs, and potential ancient examples. A classification of the various forms of diapiric activity has been erected as part of a general discussion on the importance, genesis and emplacement of mud diapirs. In addition, the general structural development of the accretionary complex in W. Sabah was found to broadly resemble that of the frontal regions of a particularly thin part of the Barbados Ridge complex studied during DSDP Leg 78A and ODP Leg 110.A series of principal controls or boundary factors appear to control the general development of accretionary complexes. During the course of this study the importance of the sedimentary input, critical taper (or balance between boundary stresses and gravitational body forces) and subducting basement topography has been made particularly clear

Histopathological analysis and in situ localisation of Australian tiger snake venom in two clinically envenomed domestic animals

Objective: To assess histopathological changes in clinically envenomed tiger snake patients and identify tissue specific localisation of venom toxins using immunohistochemistry. Samples: One feline and one canine patient admitted to the Murdoch Pet Emergency Centre (MPEC), Murdoch University with tiger snake (Notechis sp.) envenoming. Both patients died as a result of envenomation. Non-envenomed tissue was also collected and used for comparison. Methodology: Biopsy samples (heart, lung, kidney andskeletal muscle tissue) were retrieved 1-2 h post death and processed for histopathological examination using Haemotoxylin and Eosin, Martius Scarlet Blue and Periodic Acid Schiff staining. Tissues were examined by light microscopy and tissue sections subjected to immunohistochemical staining using in-house generated monoclonal and polyclonal antibodies against Notechis venoms. Results: Venom-induced pathological changes were observed in the lungs, kidneys and muscle tissue of both patients. Evidence, not previously noted, of procoagulant venom effects were apparent, with formed thrombi in the heart, lungs (small fibrillar aggregates and larger, discrete thrombi) and kidneys. Immunohistochemical assays revealed venom present in the pulmonary tissue, in and around the glomerular capsule and surrounding tubules in renal tissue and scattered throughout the Gastrocnemius muscle tissue. Conclusion: This work has shown pathological evidence of procoagulant venom activity supporting previous suggestions that an initial thrombotic state occurs in envenomed patients. We have shown that venom toxins are able to be localised to specific tissues, in this case, venom was detected in the lung, kidney and muscle tissues of clinically envenomed animals. Future work will examine specific toxin localisation using monoclonal antibodies and identify if antivenom molecules are able to reach their target tissues

QCD with dynamical Wilson fermions at β=5.5\beta=5.5

We study QCD with two flavors of dynamical Wilson fermions at $\beta = 5.5$ and three values of $\kappa$. The corresponding pion masses are 0.375, 0.324 and 0.262 in lattice units, with pion to rho mass ratios of 0.76, 0.71 and 0.62, respectively. We use the configurations to compute the heavy quark potential, leading to lattice spacings of 0.110, 0.105 and 0.099 fm, and to compute spectroscopy for several different valence quark $\kappa$'s.Comment: LaTex 4 pages, 4 figures. Talk presented at LATTICE96(spectrum

Inviscid dynamical structures near Couette flow

Consider inviscid fluids in a channel {-1<y<1}. For the Couette flow v_0=(y,0), the vertical velocity of solutions to the linearized Euler equation at v_0 decays in time. At the nonlinear level, such inviscid damping has not been proved. First, we show that in any (vorticity) H^{s}(s<(3/2)) neighborhood of Couette flow, there exist non-parallel steady flows with arbitrary minimal horizontal period. This implies that nonlinear inviscid damping is not true in any (vorticity) H^{s}(s<(3/2)) neighborhood of Couette flow and for any horizontal period. Indeed, the long time behavior in such neighborhoods are very rich, including nontrivial steady flows, stable and unstable manifolds of nearby unstable shears. Second, in the (vorticity) H^{s}(s>(3/2)) neighborhood of Couette, we show that there exist no non-parallel steadily travelling flows v(x-ct,y), and no unstable shears. This suggests that the long time dynamics in H^{s}(s>(3/2)) neighborhoods of Couette might be much simpler. Such contrasting dynamics in H^{s} spaces with the critical power s=(3/2) is a truly nonlinear phenomena, since the linear inviscid damping near Couette is true for any initial vorticity in L^2

Appendiceal malignancy: The hidden risks of nonoperative management for acute appendicitis

One potential harm of nonoperative management for acute appendicitis is missed appendiceal cancer, a rare and often aggressive malignancy due to the frequency of late stage of diagnosis. Previous studies have reported an increasing incidence of appendiceal neoplasms in the population. This is a retrospective case-control study of 1007 adult patients, who presented to the University of North Carolina-Memorial Hospital (UNC-MH) between 2011 and 2015 with clinical signs and symptoms of appendicitis. We evaluated the incidence of primary appendiceal cancer in this population and determined factors that predict appendiceal cancer diagnosis using multivariate logistic regression analysis. The overall incidence of appendiceal neoplasm for adult patients presenting to UNC-MH with appendicitis from 2011 to 2015 was 2.3 per cent (23/1007). The incidence in patients without appendiceal perforation on pathology was 1.9 per cent (16/832). Age (odds ratio (OR) 1.03), number of days of abdominal pain (OR 1.16), self-reported fever (OR 2.08), appendiceal width (OR 1.95), and appendiceal wall thickness (OR 1.30) were predictors of appendiceal neoplasm diagnosis in patients that present with acute appendicitis. We recommend that an operative approach to acute appendicitis should remain the standard of care because operative management may not only be diagnostic but potentially therapeutic

Agency as the Acquisition of Capital: the role of one-on-one tutoring and mentoring in changing a refugee student's educational trajectory

Current research into the experiences of refugee students in mainstream secondary schools in Australia indicates that for these students, schools are places of social and academic isolation and failure. This article introduces one such student, Lian, who came to Australia as a refugee from Burma, and whom the author tutored and mentored intensively during his final year of schooling. The article provides an empirically derived understanding of how one-on-one tutoring and mentoring became a platform through which this student was able to succeed in a structure which systematically tried to exclude him. Here, agency is conceptualised in terms of Bourdieu's concept of capital. The analysis highlights the ways in which one-on-one tutoring and mentoring provided the necessary platform by which this refugee student was able to acquire the necessary capital that effected a positive change in his educational trajectory

The Cost of Jointness and How to Manage It

Although joint programs are typically formed to reduce costs, recent studies have suggested that joint programs experience larger cost growth than non-joint programs. To explain this phenomenon, we present a model that attributes joint program cost growth to agencies’ actions to maintain or regain their autonomy. We use this model to motivate principles for architecting joint programs and outline a process that can be used to identify opportunities for reforming current joint programs or for establishing new ones. Finally, we apply our approach to analyze joint program options for NOAA’s low-earth orbiting weather satellite program and in doing so, identify several risks facing NOAA’s current program and strategies for mitigating them.Massachusetts Institute of Technology (Sandia Corporation Excellence in Engineering Graduate Fellowship)Skolkovo Institute of Science and Technolog

Improving zinc accumulation in barley endosperm using HvMTP1, a transition metal transporter

Zinc (Zn) is essential for all life forms, including humans. It is estimated that around two billion people are deficient in their Zn intake. Human dietary Zn intake relies heavily on plants, which in many developing countries consists mainly of cereals. The inner part of cereal grain, the endosperm, is the part that is eaten after milling but contains only a quarter of the total grain Zn. Here we present results demonstrating that endosperm Zn content can be enhanced through expression of a transporter responsible for vacuolar Zn accumulation in cereals. The barley (Hordeum vulgare) vacuolar Zn transporter HvMTP1 was expressed under the control of the endosperm-specific D-hordein promoter. Transformed plants exhibited no significant change in growth but had higher total grain Zn concentration, as measured by ICP-OES, compared to parental controls. Compared with Zn, transformants had smaller increases in concentrations of Cu and Mn but not Fe. Staining grain cross-sections with the Zn-specific stain DTZ revealed a significant enhancement of Zn accumulation in the endosperm of two of three transformed lines, a result confirmed by ICP-OES in the endosperm of dissected grain. Synchrotron X-ray fluorescence analysis of longitudinal grain sections demonstrated a redistribution of grain Zn from aleurone to endosperm. We argue that this proof-of-principle study provides the basis of a strategy for biofortification of cereal endosperm with Zn

Increased yield stability of field-grown winter barley (Hordeum vulgare L.) varietal mixtures through ecological processes

Crop variety mixtures have the potential to increase yield stability in highly variable and unpredictable environments, yet knowledge of the specific mechanisms underlying enhanced yield stability has been limited. Ecological processes in genetically diverse crops were investigated by conducting field trials with winter barley varieties (Hordeum vulgare), grown as monocultures or as three-way mixtures in fungicide treated and untreated plots at three sites. Mixtures achieved yields comparable to the best performing monocultures whilst enhancing yield stability despite being subject to multiple predicted and unpredicted abiotic and biotic stresses including brown rust (Puccinia hordei) and lodging. There was compensation through competitive release because the most competitive variety overyielded in mixtures thereby compensating for less competitive varieties. Facilitation was also identified as an important ecological process within mixtures by reducing lodging. This study indicates that crop varietal mixtures have the capacity to stabilise productivity even when environmental conditions and stresses are not predicted in advance. Varietal mixtures provide a means of increasing crop genetic diversity without the need for extensive breeding efforts. They may confer enhanced resilience to environmental stresses and thus be a desirable component of future cropping systems for sustainable arable farming