118 research outputs found

    Transient Response of Linear Elastic Structures Determined by the Matrix Exponential Method

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    This investigation was undertaken to develop a numerical solution for the transient response of linear, elastic structures based on the matrix exponential solution for first order, linear, constant coefficient differential equations. The investigation was prompted by the need for an economical technique that can be used to analyze multidegree of freedom systems exemplified by piping and structural components associated with nuclear power plants. A mathematical model characterizing the behavior of linear, elastic structures was developed by using state variables of displacement and velocity. The structure consists of beam elements of uniformly distributed mass, weightless springs, and rigid masses. The stiffness and mass matrices for the beam elements and techniques for treating boundary conditions were investigated. A digital computer program was written to perform the transient solution. The transient response was determined for three simple structures by using the computer program, and the results obtained agree favorably with previously reported analytical and experimental data

    Investigating the effectiveness of the Mediterranean diet in pregnant women for the primary prevention of asthma and allergy in high-risk infants: protocol for a pilot randomised controlled trial

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    This research is funded by the Chief Scientist Office of The Scottish Government/Chief Medical Officer Directorate (Grant CZG/2/558). The authors would like to acknowledge the staff involved in the NHS ethical and research and development review processes, and staff at the Health Records Department of the Edinburgh Royal Infirmary for their help in getting the recruitment material to potential participants. The staff at the ultrasound/X-ray clinics at the two NHS Lothian sites where the participants are met by the researcher are most helpful and accommodating. The authors thank Anne Galloway (dietitian) who, when available, is delivering the intervention at one of the sites. They would also like to thank the participants for volunteering to take part, Dr Rob Elton the independent statistician, and Julia Clark (dietitian), Dr Ulugbek Nurmatov (researcher), and our Consumer Involvement Group for their input.Peer reviewedPublisher PD

    Barriers to and Resources for Asthma Management in Vermont Elementary Schools

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    Introduction. Asthma is a chronic obstructive lung disease that causes wheezing, coughing, and shortness of breath, and is a cause of school absenteeism. School nurses play an integral role in asthma care for elementary-aged children.https://scholarworks.uvm.edu/comphp_gallery/1189/thumbnail.jp

    Island questions: the chronology of the Brochtorff Circle at Xagħra, Gozo, and its significance for the Neolithic sequence on Malta

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    Bayesian chronological modelling of radiocarbon dates from the Brochtorff Circle at Xagħra, Gozo, Malta (achieved through the ToTL and FRAGSUS projects), provides a more precise chronology for the sequence of development and use of a cave complex. Artefacts show that the site was in use from the Żebbuġ period of the late 5th/early 4th millennium cal BC to the Tarxien Cemetery phase of the later 3rd/early 2nd millennia cal BC. Absolutely dated funerary activity, however, starts with a small rock-cut tomb, probably in use in the mid to late fourth millennium cal BC, in the Ġgantija period. After an interval of centuries, burial resumed on a larger scale, probably in the 30th century cal BC, associated with Tarxien cultural material, with the use of the cave for collective burial and other depositions, with a series of structures, most notably altar-like settings built from massive stone slabs, which served to monumentalise the space. This process continued at intervals until the deposition of the last burials, probably in the 24th century cal BC; ceremonial activity may have ended at this time or a little later, to be followed by occupation in the Tarxien Cemetery period. The implications for the development of Neolithic society on Malta are discussed, as well as the changing character of Neolithic Malta in comparison to contemporary communities in Sicily, peninsular Italy and southern Iberia. It is argued that underground settings and temples on Malta may have served to reinforce locally important values of cooperation and consensus, against a wider tide of differentiation and accumulation, but that there could also have been increasing control of the treatment of the dead through time. The end of the Maltese Neolithic is also briefly discussed

    Long-term trends in human body size track regional variation in subsistence transitions and growth acceleration linked to dairying

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    Evidence for a reduction in stature between Mesolithic foragers and Neolithic farmers has been interpreted as reflective of declines in health, however, our current understanding of this trend fails to account for the complexity of cultural and dietary transitions or the possible causes of phenotypic change. The agricultural transition was extended in primary centers of domestication and abrupt in regions characterized by demic diffusion. In regions such as Northern Europe where foreign domesticates were difficult to establish, there is strong evidence for natural selection for lactase persistence in relation to dairying. We employ broad-scale analyses of diachronic variation in stature and body mass in the Levant, Europe, the Nile Valley, South Asia, and China, to test three hypotheses about the timing of subsistence shifts and human body size, that: 1) the adoption of agriculture led to a decrease in stature, 2) there were different trajectories in regions of in situ domestication or cultural diffusion of agriculture; and 3) increases in stature and body mass are observed in regions with evidence for selection for lactase persistence. Our results demonstrate that 1) decreases in stature preceded the origins of agriculture in some regions; 2) the Levant and China, regions of in situ domestication of species and an extended period of mixed foraging and agricultural subsistence, had stable stature and body mass over time; and 3) stature and body mass increases in Central and Northern Europe coincide with the timing of selective sweeps for lactase persistence, providing support for the "Lactase Growth Hypothesis.

    A Study of Zero Bid Wind Farm for Future Scotland’s Energy Demands—A New Approach

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    Offshore wind is in a rapid transitional phase, pushed worldwide by efforts of those to reduce climate change. Wind power is becoming a commercialised, unsubsidised competitive form of low carbon generation of renewable energy. Marketplaces reflect this growing trend with the first introduction of subsidy free bids in a tender for the Dutch and German governments. The analysis of surrounding literature of subsidy free bids and governmental policies revealed that integration of subsidy free bids have been carried out to various extents. Bids like those seen in the German and Dutch governments have been done in accompaniment with supportive policies and measures. For the UK, a possible subsidy free bid could be developed under the Scottish Sectoral Marine Plan. Owing to that, this paper investigates the feasibility of a subsidy free bid for the Scottish government. Utilising the Department for Business, Energy and Industrial Strategy (BEIS) levelised cost of electricity (LCOE) metric were inserted into a detailed excel spreadsheet. This paper calculates multiple financial scenarios under the LCOE metric to provide an insight into the possible scenarios of which different models of subsidy free bids can be implemented. The main parameters associated with the BEIS metric and calculator design were investigated. These included financial cost predictions, discount rate, generational capacity and net capacity factors. The final conclusion of the generated output data, showed it was indeed possible to adopt a subsidy free bid under the current UK contract for difference (CfD) scheme under strict and favourable conditions

    Targeting rehabilitation to improve outcomes after total knee arthroplasty in patients at risk of poor outcomes: randomised controlled trial

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    Objective: To evaluate whether a progressive course of outpatient physiotherapy offers superior outcomes to a single physiotherapy review and home exercise based intervention when targeted at patients with a predicted poor outcome after total knee arthroplasty.Design: Parallel group randomised controlled trial.Setting: 13 secondary and tertiary care centres in the UK providing postoperative physiotherapy.Participants: 334 participants with knee osteoarthritis who were defined as at risk of a poor outcome after total knee arthroplasty, based on the Oxford knee score, at six weeks postoperatively. 163 were allocated to therapist led outpatient rehabilitation and 171 to a home exercise based protocol.Interventions: All participants were reviewed by a physiotherapist and commenced 18 sessions of rehabilitation over six weeks, either as therapist led outpatient rehabilitation (progressive goal oriented functional rehabilitation protocol, modified weekly in one-one contact sessions) or as physiotherapy review followed by a home exercise based regimen (without progressive input from a physiotherapist).Main outcome measures: Primary outcome was Oxford knee score at 52 weeks, with a 4 point difference between groups considered to be clinically meaningful. Secondary outcomes included additional patient reported outcome measures of pain and function at 14, 26, and 52 weeks post-surgery.Results: 334 patients were randomised. Eight were lost to follow-up. Intervention compliance was more than 85%. The between group difference in Oxford knee score at 52 weeks was 1.91 (95% confidence interval ?0.18 to 3.99) points, favouring the outpatient rehabilitation arm (P=0.07). When all time point data were analysed, the between group difference in Oxford knee score was a non-clinically meaningful 2.25 points (0.61 to 3.90, P=0.01). No between group differences were found for secondary outcomes of average pain (0.25 points, ?0.78 to 0.28, P=0.36) or worst pain (0.22 points, ?0.71 to 0.41, P=0.50) at 52 weeks or earlier time points, or of satisfaction with outcome (odds ratio 1.07, 95% confidence interval 0.71 to 1.62, P=0.75) or post-intervention function (4.64 seconds, 95% confidence interval ?14.25 to 4.96, P=0.34).Conclusions: Outpatient therapist led rehabilitation was not superior to a single physiotherapist review and home exercise based regimen in patients at risk of poor outcomes after total knee arthroplasty. No clinically relevant differences were observed across primary or secondary outcome measures.Trials registration: Current Controlled Trials ISRCTN23357609 and ClinicalTrials.gov NCT01849445

    Human Herpesvirus 6 (HHV-6) Causes Severe Thymocyte Depletion in SCID-hu Thy/Liv Mice

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    Human herpesvirus 6 (HHV-6) is a potentially immunosuppressive agent that may act as a cofactor in the progression of AIDS. Here, we describe the first small animal model of HHV-6 infection. HHV-6 subgroup A, strain GS, efficiently infected the human thymic tissue implanted in SCID-hu Thy/Liv mice, leading to the destruction of the graft. Viral DNA was detected in Thy/Liv implants by quantitative polymerase chain reaction (PCR) as early as 4 d after inoculation and peaked at day 14. The productive nature of the infection was confirmed by electron microscopy and immunohistochemical staining. Atypical thymocytes with prominent nuclear inclusions were detected by histopathology. HHV-6 replication was associated with severe, progressive thymocyte depletion involving all major cellular subsets. However, intrathymic T progenitor cells (ITTPs) appeared to be more severely depleted than the other subpopulations, and a preferred tropism of HHV-6 for ITTPs was demonstrated by quantitative PCR on purified thymocyte subsets. These findings suggest that thymocyte depletion by HHV-6 may be due to infection and destruction of these immature T cell precursors. Similar results were obtained with strain PL-1, a primary isolate belonging to subgroup B. The severity of the lesions observed in this animal model underscores the possibility that HHV-6 may indeed be immunosuppressive in humans
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