4,730 research outputs found

    Mental health services required after disasters: Learning from the lasting effects of disasters

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    Extent: 13p.Disasters test civil administrations’ and health services’ capacity to act in a flexible but well-coordinated manner because each disaster is unique and poses unusual challenges. The health services required differ markedly according to the nature of the disaster and the geographical spread of those affected. Epidemiology has shown that services need to be equipped to deal with major depressive disorder and grief, not just posttraumatic stress disorder, and not only for victims of the disaster itself but also the emergency service workers. The challenge is for specialist advisers to respect and understand the existing health care and support networks of those affected while also recognizing their limitations. In the initial aftermath of these events, a great deal of effort goes into the development of early support systems but the longer term needs of these populations are often underestimated. These services need to be structured, taking into account the pre-existing psychiatric morbidity within the community. Disasters are an opportunity for improving services for patients with posttraumatic psychopathology in general but can later be utilized for improving services for victims of more common traumas in modern society, such as accidents and interpersonal violence.A. C. McFarlane and Richard William

    The Quaternary Bone Caves and Associated Sites at Wallingford, Jamaica

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    A group of caves associated with the sink of the One Eye River in St. Elizabeth Parish, Jamaica, have been the subject of numerous important palaeontological investigations beginning 1919. Unfortunately, considerable confusion has arisen in the literature through inadequate documentation of different sites. The caves of the immediate area are described and located, and their palaeontological significance is summarised in the light of recent taxonomic review and relevant geochronological evidence

    Design and fabrication of a long-life Stirling cycle cooler for space application. Phase 3: Prototype model

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    A second-generation, Stirling-cycle cryocooler (cryogenic refrigerator) for space applications, with a cooling capacity of 5 watts at 65 K, was recently completed. The refrigerator, called the Prototype Model, was designed with a goal of 5 year life with no degradation in cooling performance. The free displacer and free piston of the refrigerator are driven directly by moving-magnet linear motors with the moving elements supported by active magnetic bearings. The use of clearance seals and the absence of outgassing material in the working volume of the refrigerator enable long-life operation with no deterioration in performance. Fiber-optic sensors detect the radial position of the shafts and provide a control signal for the magnetic bearings. The frequency, phase, stroke, and offset of the compressor and expander are controlled by signals from precision linear position sensors (LVDTs). The vibration generated by the compressor and expander is cancelled by an active counter balance which also uses a moving-magnet linear motor and magnetic bearings. The driving signal for the counter balance is derived from the compressor and expander position sensors which have wide bandwidth for suppression of harmonic vibrations. The efficiency of the three active members, which operate in a resonant mode, is enhanced by a magnetic spring in the expander and by gas springs in the compressor and counterbalance. The cooling was achieved with a total motor input power of 139 watts. The magnetic-bearing stiffness was significantly increased from the first-generation cooler to accommodate shuttle launch vibrations

    Customising with 3D printing: The role of intelligent control

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    © 2018 Elsevier B.V. The emergence of direct digital manufacturing creates new opportunities for the production of highly customised goods especially when it is combined with conventional manufacturing methods. Nevertheless, this combination creates a need for systems that can effectively manage and control the resulting distributed manufacturing process. In this paper, we explore three different configurations that can enable direct digital manufacturing for customisation, ranging from fully integrated to inter-organisational set up. Additionally, control requirements of such systems are developed and the suitability of intelligent control is explored. By ‘intelligent control’ we mean production control that is capable of assessing and interacting with the production environment and adapting production accordingly. We argue that the so called intelligent product paradigm provides a suitable mechanism for the development of such intelligent control systems. In this approach, the intelligent product directly co-ordinates with design agent, 3D printing agents and other conventional manufacturing system agents to schedule, assign and execute tasks independently. Via a case example of a realistic production system, we propose and implement such an intelligent control system and we analyse its feasibility in supporting 3D printing enabled customisation

    Coulomb interactions in single, charged self-assembled quantum dots: radiative lifetime and recombination energy

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    We present results on the charge dependence of the radiative recombination lifetime, Tau, and the emission energy of excitons confined to single self-assembled InGaAs quantum dots. There are significant dot-to-dot fluctuations in the lifetimes for a particular emission energy. To reach general conclusions, we present the statistical behavior by analyzing data recorded on a large number of individual quantum dots. Exciton charge is controlled with extremely high fidelity through an n-type field effect structure, providing access to the neutral exciton (X0), the biexciton (2X0) and the positively (X1+) and negatively (X1-) charged excitons. We find significant differences in the recombination lifetime of each exciton such that, on average, Tau(X1-) / Tau(X0) = 1.25, Tau(X1+) / Tau(X0) = 1.58 and Tau(2X0) / Tau(X0) = 0.65. We attribute the change in lifetime to significant changes in the single particle hole wave function on charging the dot, an effect more pronounced on charging X0 with a single hole than with a single electron. We verify this interpretation by recasting the experimental data on exciton energies in terms of Coulomb energies. We show directly that the electron-hole Coulomb energy is charge dependent, reducing in value by 5-10% in the presence of an additional electron, and that the electron-electron and hole-hole Coulomb energies are almost equal.Comment: 8 pages, 7 figures, submitted to Phys. Rev.

    Investigation of a saline valley on Allandale Research Farm

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    Geophysical surveys and drilling were used to investigate a saline valley on Allandale Research Farm. These techniques showed that the geology is controlling the location of two main areas of saline seeps and they identified another area at risk of increased salinity. They were also used to obtain information on the groundwater system and to assist in making management recommendations. Electromagnetic terrain conductivity surveys showed that the most saline soils occurred upstream of a cross-cutting magnetic anomaly caused by a dolerite dyke. A seismic survey showed that the anomaly coincided with a bedrock rise. This bedrock rise restricts groundwater flow through the catchment and forces saline groundwater to the surface where it evaporates causing salts to build up in the soil profile. A second area of saline surface soils occurs further downstream. Outcrops of granite in the creek indicate that another bedrock rise is the cause for the location of this seep. A third area in the valley upslope from the main saline area has a high subsoil conductivity and is immediately upslope of a second magnetic anomaly. This area may become more saline in the future. Drilling confirmed the seismic profile near the dolerite dyke in the main saline area. It also indicated that deep groundwater pressures are above ground level along the whole of the valley/ becoming higher with increased distance downstream. The quality of the groundwater ranged from 3,500 to 6,500 mg.Cl-1/L. Three recommendations are made for the area: (i) the construction of an interceptor drain/ upslope of each saline area, to reduce waterlogging; (ii) fencing the saline areas, and revegetating to salt tolerant grasses, bushes and trees; (iii) limiting recharge on coarse textured soils in the catchment above the valley by growing crops and/or trees with high evapotranspiration potentials

    An in situ XAS study of the cobalt rhenium catalyst for ammonia synthesis

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    A cobalt rhenium catalyst active for ammonia synthesis at 400 °C and ambient pressure was studied using in situ XAS to elucidate the reducibility and local environment of the two metals during reaction conditions. The ammonia reactivity is greatly affected by the gas mixture used in the pre-treatment step. Following H2/Ar pre-treatment, a subsequent 20 min induction period is also observed before ammonia production occurs whereas ammonia production commences immediately following comparable H2/N2 pre-treatment. In situ XAS at the Co K-edge and Re LIII-edge show that cobalt initiates reduction, undergoing reduction between 225 and 300 °C, whereas reduction of rhenium starts at 300 °C. The reduction of rhenium is near complete below 400 °C, as also confirmed by H2-TPR measurements. A synergistic co-metal effect is observed for the cobalt rhenium system, as complete reduction of both cobalt and rhenium independently requires higher temperatures. The phases present in the cobalt rhenium catalyst during ammonia production following both pre-treatments are largely bimetallic Co–Re phases, and also monometallic Co and Re phases. The presence of nitrogen during the reduction step strongly promotes mixing of the two metals, and the bimetallic Co–Re phase is believed to be a pre-requisite for activity

    The relationship between Hippocampal asymmetry and working memory processing in combat-related PTSD: a monozygotic twin study

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    BACKGROUND: PTSD is associated with reduction in hippocampal volume and abnormalities in hippocampal function. Hippocampal asymmetry has received less attention, but potentially could indicate lateralised differences in vulnerability to trauma. The P300 event-related potential component reflects the immediate processing of significant environmental stimuli and has generators in several brain regions including the hippocampus. P300 amplitude is generally reduced in people with PTSD. METHODS: Our study examined hippocampal volume asymmetry and the relationship between hippocampal asymmetry and P300 amplitude in male monozygotic twins discordant for Vietnam combat exposure. Lateralised hippocampal volume and P300 data were obtained from 70 male participants, of whom 12 had PTSD. We were able to compare (1) combat veterans with current PTSD; (2) their non-combat-exposed co-twins; (3) combat veterans without current PTSD and (4) their non-combat-exposed co-twins. RESULTS: There were no significant differences between groups in hippocampal asymmetry. There were no group differences in performance of an auditory oddball target detection task or in P300 amplitude. There was a significant positive correlation between P300 amplitude and the magnitude of hippocampal asymmetry in participants with PTSD. CONCLUSIONS: These findings suggest that greater hippocampal asymmetry in PTSD is associated with a need to allocate more attentional resources when processing significant environmental stimuli.Timothy Hall, Cherrie Galletly, C.R. Clark, Melinda Veltmeyer, Linda J. Metzger, Mark W. Gilbertson, Scott P. Orr, Roger K. Pitman and Alexander McFarlan

    Removal of Arsenic (III) from groundwater applying a reusable Mg-Fe-Cl layered double hydroxide

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    BACKGROUND: Layered double hydroxide compounds (LDHs) have been applied for the removal of oxyanions including arsenate (As(V)). However, the aim of this present research is to develop a LDH to treat arsenite (As(III)). Both batch and column sorption studies were conducted to assess the effect of LDH dosage, contact time, solution pH and initial As(III) concentrations on the As(III) removal performance. The potential re-use of this sorbent was also investigated.<p></p> RESULTS: For 2 g L−1 of Mg-Fe-Cl LDH, As(III) in test solution can be reduced from 400 µg L−1 to <10 µg L−1 after a contact time of 2 h. High As(III) concentration in Bangladesh groundwater can be reduced to meet the national drinking water standards (<50 µg L−1). The maximum adsorption capacity of As(III) by Mg-Fe-Cl LDH is 14.6 mg g−1-LDH. Further, reusability of this sorbent was at least 20 cycles of regeneration with effective As(III) removal between 93.0 and 98.5%. Moreover, As(III) removal was unaffected by the solution pH but affected by the co-existing competing anions and concentration of As(III). Finally, the main mechanism of As(III) removal by Mg-Fe-Cl LDH was suggested to be chemical sorption together with anion and ligand exchange with interlayer Cl− and OH− ions.<p></p> CONCLUSION: High efficiency of sorption of As(III) by the developed Mg-Fe-Cl LDH was demonstrated in this study which is generally not the case for most other sorbent materials. Pilot-scale trials are needed to explore the suitability of full application of the developed Mg-Fe-Cl LDH for the removal of As(III).<p></p&gt
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