978 research outputs found

    Positive practices : solution-focused and narrative therapeutic techniques with children with sexually harmful behaviours

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    This article explores the use of solution-focused and Narrative Therapeutic approaches with a boy who had sexually harmful behaviours. The paper will highlight the practical challenges of working with someone who is 'problem-saturated' through institutionalisation and who is also subjected to powerful discourses claiming the 'truth' about him. The use of solution-focused and Narrative Therapeutic principles and approaches will be demonstrated in the work described, in a way that allows the reader to reflect on how these may differ from modernist understandings and responses to this behaviour

    The massive expanding molecular torus in the planetary nebula NGC 6302

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    We measure the mass and kinematics of the massive molecular torus in the planetary nebula NGC 6302. The nebula is the proto-typical butterfly nebula. The origin of the wing-like morphology is disputed: determining the mass-loss history of the confining torus is an important step in understanding the formation of this structure. We performed submillimeter observations with JCMT and the SMA interferometer. The continuum emission as well as the J=2-1 and 3-2 transitions of 12CO and 13CO are analysed at arcsecond resolution. The CO emission indicates a mass of the torus of ~ 2Msun +/- 1Msun. The 12CO and 13CO emission matches the dark lane seen in absorption in the Halpha image of the object. The CO torus is expanding with a velocity of ~ 8 km/s, centred at Vlsr=-31.5 km/s. The size and expansion velocity of the torus indicates that the torus was ejected from ~ 7500 yr to 2900 yr ago, with a mass-loss rate of 5x10^{-4}Msun/yr. We also see a ballistic component in the CO images with a velocity gradient of 140 km/s/pc. The derived mass-loss history of the torus favours binary interaction as the cause of the ejection of the torus. We predict the existence of a companion with an orbital period P < 1 month.Comment: 13 pages, 10 figures, accepted for publication in A&

    Hepatosplenic schistosomiasis in Zambian adults is characterized by increased liver stiffness: A nested case-control study.

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    Cirrhosis commonly complicates portal hypertension worldwide but in Zambia hepatosplenic schistosomiasis (HSS) dominates as the cause of portal hypertension. We need easier and non-invasive ways to assess HSS. Transient elastography (TE), a measure of liver stiffness can diagnose liver cirrhosis. TE remains unexplored in HSS patients, who generally have normal liver parenchyma. We aimed to explore liver stiffness in HSS. This nested case control study was conducted at the University Teaching Hospital, Lusaka, Zambia between January 2015 and January 2016. We enrolled 48 adults with HSS and 22 healthy controls. We assessed liver stiffness using TE while plasma hyaluronan was used to assess liver fibrosis. Plasma tumor necrosis factor receptor 1 (TNFR1) and soluble cluster of differentiation 14 (sCD14) were used to assess inflammation. The median (interquartile range) liver stiffness was higher in patients, 9.5 kPa (7.8, 12.8) than in controls, 4.7 kPa (4.0, 5.4), P < 0.0001. We noted linear correlations of hyaluronan and TNFR1 with the liver stiffness, P = 0.0307 and P = 0.0003 respectively. HSS patients seem to have higher liver stiffness than healthy controls. TE may be useful in identifying fibrosis in HSS. The positive correlations of inflammatory markers with TE suggest that HSS has both periportal and parenchymal pathophysiology

    Experimental evaluation of the wake characteristics of cross flow turbine arrays

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    One key factor in the exploitation of tidal energy is the study of interactions of turbines when working in tidal turbine farms. The Momentum Reversal and Lift (MRL) turbine is a novel cross flow turbine. The three blades rotate around a common central horizontal axis which is parallel to their own axis and perpendicular to the flow. The novelty of the MRL turbine is that it relies on the combination of both lift and momentum reversal (drag) for energy extraction. Scaled MRL turbine models of 0.164 m in diameter were used to characterise the flow in three different tidal array settings. Detailed maps of axial velocity profiles and velocity deficits downstream of the turbine are presented, enabling the visualisation of characteristic flow patterns. The results show that the MRL generates lower velocity deficits and turbulence intensities in the near wake than those associated with horizontal axis turbines. The downstream wake was not completely symmetrical which was related to the geometry of the device but also due to the flow developed in the flume. Amongst the three array configurations studied, a fence of turbines with the lowest separation provided the highest power output

    Reflecting on the Design and Implementation Issues of Virtual Environments

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    We present a candid reflection on the issues surrounding virtual environment design and implementation (VEDI) in order to: (1) motivate the topic as a research-worthy undertaking, and (2) attempt a comprehensive listing of impeding VEDI issues so they can be addressed. In order to structure this reflection, an idealized model of VEDI is presented. This model, investigated using mixed methods, resulted in 67 distinct issues along the model\u27s transitions and pathways. These were clustered into 11 themes and used to support five VEDI research challenges

    c-Type Cytochrome-Dependent Formation of U(IV) Nanoparticles by Shewanella oneidensis

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    Modern approaches for bioremediation of radionuclide contaminated environments are based on the ability of microorganisms to effectively catalyze changes in the oxidation states of metals that in turn influence their solubility. Although microbial metal reduction has been identified as an effective means for immobilizing highly-soluble uranium(VI) complexes in situ, the biomolecular mechanisms of U(VI) reduction are not well understood. Here, we show that c-type cytochromes of a dissimilatory metal-reducing bacterium, Shewanella oneidensis MR-1, are essential for the reduction of U(VI) and formation of extracelluar UO (2) nanoparticles. In particular, the outer membrane (OM) decaheme cytochrome MtrC (metal reduction), previously implicated in Mn(IV) and Fe(III) reduction, directly transferred electrons to U(VI). Additionally, deletions of mtrC and/or omcA significantly affected the in vivo U(VI) reduction rate relative to wild-type MR-1. Similar to the wild-type, the mutants accumulated UO (2) nanoparticles extracellularly to high densities in association with an extracellular polymeric substance (EPS). In wild-type cells, this UO (2)-EPS matrix exhibited glycocalyx-like properties and contained multiple elements of the OM, polysaccharide, and heme-containing proteins. Using a novel combination of methods including synchrotron-based X-ray fluorescence microscopy and high-resolution immune-electron microscopy, we demonstrate a close association of the extracellular UO (2) nanoparticles with MtrC and OmcA (outer membrane cytochrome). This is the first study to our knowledge to directly localize the OM-associated cytochromes with EPS, which contains biogenic UO (2) nanoparticles. In the environment, such association of UO (2) nanoparticles with biopolymers may exert a strong influence on subsequent behavior including susceptibility to oxidation by O (2) or transport in soils and sediments

    Design and manufacture of a bed supported tidal turbine model for blade and shaft load measurement in turbulent flow and waves

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    Laboratory testing of tidal turbine models is an essential tool to investigate hydrodynamic interactions between turbines and the flow. Such tests can be used to calibrate numerical models and to estimate rotor loading and wake development to inform the design of full scale machines and array layout. The details of the design and manufacturing techniques used to develop a highly instrumented turbine model are presented. The model has a 1.2 m diameter, three bladed horizontal axis rotor and is bottom mounted. Particular attention is given to the instrumentation which can measure streamwise root bending moment for each blade and torque and thrust for the overall rotor. The model is mainly designed to investigate blade and shaft loads due to both turbulence and waves. Initial results from tests in a 2 m deep by 4 m wide flume are also presented

    An all-solid-state laser source at 671 nm for cold atom experiments with lithium

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    We present an all solid-state narrow line-width laser source emitting 670 mW670\,\mathrm{mW} output power at 671 nm671\,\mathrm{nm} delivered in a diffraction-limited beam. The \linebreak source is based on a fre-quency-doubled diode-end-linebreak pumped ring laser operating on the 4F3/2→4I13/2{^4F}_{3/2} \rightarrow {^4I}_{13/2} transition in Nd:YVO4_4. By using periodically-poled po-tassium titanyl phosphate (ppKTP) in an external build-up cavity, doubling efficiencies of up to 86% are obtained. Tunability of the source over 100 GHz100\,\rm GHz is accomplished. We demonstrate the suitability of this robust frequency-stabilized light source for laser cooling of lithium atoms. Finally a simplified design based on intra-cavity doubling is described and first results are presented
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