2,600 research outputs found

    Collaborative procurement and private-sector housebuilding and refurbishment works: A pilot study investigation of the UK

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    Purpose Framed as a pilot study, the purpose of this paper is to study the perceived appropriateness of an existing collaborative procurement procedures (CPP) framework from the housebuilder’s perspective; seeking to improve its utility and stimulate further exploration. Design/methodology/approach Informed by an existing CPP framework, and conducted by a UK-based development professional, four in-depth semi-structured interviews were undertaken with senior housebuilding practitioners from London and surrounding counties. A qualitative analysis was then conducted for this sociological study. Findings Perceived appropriateness of the framework was high; however, a number of procedural improvements were identified, along with limitations. Future studies are recommended including the influence upon project performance of groundworker integration at the design stage. Research limitations/implications Limited to four interviews from one regional area, the study is an initial insight into the appropriateness of an existing CPP framework. Insights into why CP uptake is marginal within housebuilding were also gained. The research purpose was achieved but by offering a self-reflection upon practice (vis-à-vis wider generalisations) the findings provide a springboard for further studies. Practical implications The research identifies with current practice, industry perceptions, and paths towards improving the utility of the CPP framework. Social implications This study offers insights into the perceptions of private housebuilding practitioners of their own practices and the factors they find challenging within the social constructs of their industry. Originality/value This research constitutes one of the first studies in the UK to examine the CPP framework from the perspective of the private housebuilder and is undertaken with the express purpose of furthering that framework’s utility

    Anomalous diffusion in polymers: long-time behaviour

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    We study the Dirichlet boundary value problem for viscoelastic diffusion in polymers. We show that its weak solutions generate a dissipative semiflow. We construct the minimal trajectory attractor and the global attractor for this problem.Comment: 13 page

    Mobile EEG reveals functionally dissociable dynamic processes supporting real-world ambulatory obstacle avoidance : evidence for early proactive control

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    This work is supported by a scholarship from the University of Stirling and a reseach grant from SINAPSE (Scottish Imaging Network: A Platform for Scientific excellence). GL is supported by the Wellcome Trust [209209/Z/17/Z].The ability to safely negotiate the world on foot takes humans years to develop, reflecting the huge cognitive demands associated with real‐time planning and control of walking. Despite the importance of walking, methodological limitations mean that surprisingly little is known about the neural and cognitive processes that support ambulatory motor control. Here, we report mobile EEG data recorded from thirty‐two healthy young adults during real‐world ambulatory obstacle avoidance. Participants walked along a path while stepping over expected and unexpected obstacles projected on the floor, allowing us to capture the dynamic oscillatory response to changes in environmental demands. Compared to obstacle‐free walking, time‐frequency analysis of the EEG data revealed clear frontal theta and centro‐parietal beta power neural markers of proactive and reactive forms of movement control (occurring before and after crossing an obstacle). Critically, the temporal profile of changes in frontal theta allowed us to arbitrate between early selection and late adaptation mechanisms of proactive control. Our data show that motor plans are updated as soon as an upcoming obstacle appears, rather than when the obstacle is reached. In addition, regardless of whether motor plans required updating, a clear beta rebound was present after obstacles were crossed, reflecting the resetting of the motor system. Overall, mobile EEG recorded during real‐world walking provides novel insight into the cognitive and neural basis of dynamic motor control in humans, suggesting new routes to the monitoring and rehabilitation of motor disorders such as dyspraxia and Parkinson’s disease.Publisher PDFPeer reviewe

    Missed opportunities for tuberculosis prevention among patients accessing a UK HIV service.

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    United Kingdom guidelines recommend screening for and treatment of latent tuberculosis infection (LTBI) in HIV-positive patients at high risk of active tuberculosis (TB) disease, but implementation is suboptimal. We investigated potential missed opportunities to identify and treat LTBI among HIV-positive patients accessing a large HIV outpatient service in London. Case records of all adult patients attending our service for HIV care diagnosed with active TB between 2011 and 2015 were reviewed to determine whether they met criteria for LTBI screening and whether screening was undertaken. Twenty-five patients were treated for TB. Of 15 (60%) patients who started TB treatment ≥6 months after HIV diagnosis, 14 (93%) met UK guideline-recommended criteria for LTBI screening and treatment; only one (7%) had been screened for LTBI. Eight of these 15 (53%) patients had additional risk factors for TB which are not reflected in current UK guidelines. Of 15 patients treated for TB ≥6 months after diagnosis of HIV, 14 (93%) had not been screened for LTBI, suggesting missed opportunities for TB prevention. People living with HIV may benefit from a broader approach to LTBI screening which takes into account additional recognised TB risk factors and ongoing TB exposure

    Genetic diversity, demographic history and neo-sex chromosomes in the Critically Endangered Raso lark

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    Small effective population sizes could expose island species to inbreeding and loss of genetic variation. Here, we investigate factors shaping genetic diversity in the Raso lark, which has been restricted to a single islet for approximately 500 years, with a population size of a few hundred. We assembled a reference genome for the related Eurasian skylark and then assessed diversity and demographic history using RAD-seq data (75 samples from Raso larks and two related mainland species). We first identify broad tracts of suppressed recombination in females, indicating enlarged neo-sex chromosomes. We then show that genetic diversity across autosomes in the Raso lark is lower than in its mainland relatives, but inconsistent with long-term persistence at its current population size. Finally, we find that genetic signatures of the recent population contraction are overshadowed by an ancient expansion and persistence of a very large population until the human settlement of Cape Verde. Our findings show how genome-wide approaches to study endangered species can help avoid confounding effects of genome architecture on diversity estimates, and how present-day diversity can be shaped by ancient demographic events

    Fusarium langsethiae and mycotoxin contamination in oat grain differed with growth stage at inoculation

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    High levels of mycotoxins are occasionally observed in Norwegian oat grain lots. Mycotoxins of primary concern in Norwegian oats are deoxynivalenol (DON) produced by Fusarium graminearum and HT2- and T2-toxins (HT2 + T2) produced by Fusarium langsethiae. Improved understanding of the epidemiology of Fusarium spp. is important for the development of measures to control mycotoxins. We studied the susceptibility to F. langsethiae after inoculation at early (booting, heading, flowering) or late (flowering, milk, dough) growth stages in three oat varieties in greenhouse experiments. The varieties had previously shown different levels of resistance to F. graminearum: Odal, Vinger (both moderately resistant), and Belinda (susceptible). The level of F. langsethiae DNA and HT2 + T2 were measured in harvested grain. In addition, we observed differences in aggressiveness (measured as the level of F. langsethiae DNA in grain) between F. langsethiae isolates after inoculation of oats at flowering. Substantial levels of F. langsethiae DNA (mean ≥ 138 pg per μg plant DNA) and HT2 + T2 (≥348 μg/kg) were detected in grain harvested from oats that were spray-inoculated at heading or later stages, but not at booting (mean ≤ 10 pg/μg and ≤ 25 μg/kg, respectively), suggesting that oats are susceptible to F. langsethiae from heading and onwards. Vinger was the most resistant variety to F. langsethiae/HT2 + T2, whereas Odal and Belinda were relatively susceptible. We observed that late inoculations yielded high levels of other trichothecene A metabolites (mean sum of metabolites of 35–1048 μg/kg) in addition to HT2 + T2, in harvested grain, an indication that infections close to harvest may pose a further risk to food and feed safety.publishedVersio

    The 'Antiretrovirals, Sexual Transmission Risk and Attitudes' (ASTRA) study. Design, methods and participant characteristics.

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    Life expectancy for people diagnosed with HIV has improved dramatically however the number of new infections in the UK remains high. Understanding patterns of sexual behaviour among people living with diagnosed HIV, and the factors associated with having condom-less sex, is important for informing HIV prevention strategies and clinical care. In addition, in view of the current interest in a policy of early antiretroviral treatment (ART) for all people diagnosed with HIV in the UK, it is of particular importance to assess whether ART use is associated with increased levels of condom-less sex. In this context the ASTRA study was designed to investigate current sexual activity, and attitudes to HIV transmission risk, in a large unselected sample of HIV-infected patients under care in the UK. The study also gathered background information on demographic, socio-economic, lifestyle and disease-related characteristics, and physical and psychological symptoms, in order to identify other key factors impacting on HIV patients and the behaviours which underpin transmission. In this paper we describe the study rationale, design, methods, response rate and the demographic characteristics of the participants. People diagnosed with HIV infection attending 8 UK HIV out-patient clinics in 2011-2012 were invited to participate in the study. Those who agreed to participate completed a confidential, self-administered pen-and-paper questionnaire, and their latest CD4 count and viral load test results were recorded. During the study period, 5112 eligible patients were invited to take part in the study and 3258 completed questionnaires were obtained, representing a response rate of 64% of eligible patients. The study includes 2248 men who have sex with men (MSM), 373 heterosexual men and 637 women. Future results from ASTRA will be a key resource for understanding HIV transmission within the UK, targeting prevention efforts, and informing clinical care of individuals living with HIV

    Feedback-optimized parallel tempering Monte Carlo

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    We introduce an algorithm to systematically improve the efficiency of parallel tempering Monte Carlo simulations by optimizing the simulated temperature set. Our approach is closely related to a recently introduced adaptive algorithm that optimizes the simulated statistical ensemble in generalized broad-histogram Monte Carlo simulations. Conventionally, a temperature set is chosen in such a way that the acceptance rates for replica swaps between adjacent temperatures are independent of the temperature and large enough to ensure frequent swaps. In this paper, we show that by choosing the temperatures with a modified version of the optimized ensemble feedback method we can minimize the round-trip times between the lowest and highest temperatures which effectively increases the efficiency of the parallel tempering algorithm. In particular, the density of temperatures in the optimized temperature set increases at the "bottlenecks'' of the simulation, such as phase transitions. In turn, the acceptance rates are now temperature dependent in the optimized temperature ensemble. We illustrate the feedback-optimized parallel tempering algorithm by studying the two-dimensional Ising ferromagnet and the two-dimensional fully-frustrated Ising model, and briefly discuss possible feedback schemes for systems that require configurational averages, such as spin glasses.Comment: 12 pages, 14 figure
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