7,377 research outputs found

    Towards designing robust coupled networks

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    Natural and technological interdependent systems have been shown to be highly vulnerable due to cascading failures and an abrupt collapse of global connectivity under initial failure. Mitigating the risk by partial disconnection endangers their functionality. Here we propose a systematic strategy of selecting a minimum number of autonomous nodes that guarantee a smooth transition in robustness. Our method which is based on betweenness is tested on various examples including the famous 2003 electrical blackout of Italy. We show that, with this strategy, the necessary number of autonomous nodes can be reduced by a factor of five compared to a random choice. We also find that the transition to abrupt collapse follows tricritical scaling characterized by a set of exponents which is independent on the protection strategy

    Production, purification and characterization of celullase-free xylanase from Aspergillus terreus UL 4209

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    Aspergillus terreus, UL 4209 strain, isolated from the soil in South Africa was used to produce an extracellular cellulase-free xylanase in shake flask cultures containing oat spelt and/or birchwoodxylans. Maximum xylanase activity (35 U/ml) was observed after 96 h at 35ºC and pH 6 in 1% oat spelt xylan. The xylanase was purified to homogeneity by gel filtration on Sephacryl S-200. This enzyme wasfound to be a single subunit protein of 22 kDa showing optimal activity at 35ºC and pH 6. The enzyme retained 95% activity at 35 - 40ºC after 4 h incubation at pH 6 and at 50ºC the half-life was 5.8 h. Theapparent Km and Vmax values were 3.57 mg/ml and 55.5 mol/min per mg protein, respectively. MALDITOF and LC mass spectroscopy gave 8 peptide ions whose sequence alignments showed that thexylanase produced by this strain has homology with those of other Aspergillus strains such as A. terreus and A. versicolor. These observations showed that our strain produced a low molecular weight,acidophilic, and thermostable xylanase that may be considered for processes operated at moderate temperatures and pH such as preparation of baked cereal food, clarification of fruit juices andsaccharification of agro-residues

    Does a modified STarT Back Tool predict outcome with a broader group of musculoskeletal patients than back pain? A secondary analysis of cohort data.

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    OBJECTIVES: The STarT Back Tool has good predictive performance for non-specific low back pain in primary care. We therefore aimed to investigate whether a modified STarT Back Tool predicted outcome with a broader group of musculoskeletal patients, and assessed the consequences of using existing risk-group cut-points across different pain regions. SETTING: Secondary analysis of prospective data from 2 cohorts: (1) outpatient musculoskeletal physiotherapy services (PhysioDirect trial n=1887) and (2) musculoskeletal primary-secondary care interface services (SAMBA study n=1082). PARTICIPANTS: Patients with back, neck, upper limb, lower limb or multisite pain with a completed modified STarT Back Tool (baseline) and 6-month physical health outcome (Short Form 36 (SF-36)). OUTCOMES: Area under the receiving operator curve (AUCs) tested discriminative abilities of the tool's baseline score for identifying poor 6-month outcome (SF-36 lower tertile Physical Component Score). Risk-group cut-points were tested using sensitivity and specificity for identifying poor outcome using (1) Youden's J statistic and (2) a clinically determined rule that specificity should not fall below 0.7 (false-positive rate <30%). RESULTS: In PhysioDirect and SAMBA, poor 6-month physical health was 18.5% and 28.2%, respectively. Modified STarT Back Tool score AUCs for predicting outcome in back pain were 0.72 and 0.79, neck 0.82 and 0.88, upper limb 0.79 and 0.86, lower limb 0.77 and 0.83, and multisite pain 0.83 and 0.82 in PhysioDirect and SAMBA, respectively. Differences between pain region AUCs were non-significant. Optimal cut-points to discriminate low-risk and medium-risk/high-risk groups depended on pain region and clinical services. CONCLUSIONS: A modified STarT Back Tool similarly predicts 6-month physical health outcome across 5 musculoskeletal pain regions. However, the use of consistent risk-group cut-points was not possible and resulted in poor sensitivity (too many with long-term disability being missed) or specificity (too many with good outcome inaccurately classified as 'at risk') for some pain regions. The draft tool is now being refined and validated within a new programme of research for a broader musculoskeletal population. TRIAL REGISTRATION NUMBER: ISRCTN55666618; Post results

    Management of shoulder pain by UK general practitioners (GPs): a national survey

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    OBJECTIVES: Studies in Canada, the USA and Australia suggested low confidence among general practitioners (GPs) in diagnosing and managing shoulder pain, with frequent use of investigations. There are no comparable studies in the UK; our objective was to describe the diagnosis and management of shoulder pain by GPs in the UK. METHODS: A national survey of a random sample of 5000 UK GPs collected data on shoulder pain diagnosis and management using two clinical vignettes that described primary care presentations with rotator cuff tendinopathy (RCT) and adhesive capsulitis (AdhC). RESULTS: Seven hundred and fourteen (14.7%) responses were received. 56% and 83% of GPs were confident in their diagnosis of RCT and AdhC, respectively, and a wide range of investigations and management options were reported. For the RCT presentation, plain radiographs of the shoulder were most common (60%), followed by blood tests (42%) and ultrasound scans (USS) (38%). 19% of those who recommended a radiograph and 76% of those who recommended a USS did so 'to confirm the diagnosis'. For the AdhC presentation, the most common investigations were blood tests (60%), plain shoulder radiographs (58%) and USS (31%). More than two-thirds of those recommending a USS did so 'to confirm the diagnosis'. The most commonly recommended treatment for both presentations was physiotherapy (RCT 77%, AdhC 71%) followed by non-steroidal anti-inflammatory drugs (RCT 58%, AdhC 74%). 17% opted to refer the RCT to secondary care (most often musculoskeletal interface service), compared with 31% for the AdhC. CONCLUSIONS: This survey of GPs in the UK highlights reliance on radiographs and blood tests in the management of common shoulder pain presentations. GPs report referring more than 7 out of 10 patients with RCT and AdhC to physiotherapists. These findings need to be viewed in the context of low response to the survey and, therefore, potential non-response bias

    Automatic correction of hand pointing in stereoscopic depth

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    In order to examine whether stereoscopic depth information could drive fast automatic correction of hand pointing, an experiment was designed in a 3D visual environment in which participants were asked to point to a target at different stereoscopic depths as quickly and accurately as possible within a limited time window (≤300 ms). The experiment consisted of two tasks: "depthGO" in which participants were asked to point to the new target position if the target jumped, and "depthSTOP" in which participants were instructed to abort their ongoing movements after the target jumped. The depth jump was designed to occur in 20% of the trials in both tasks. Results showed that fast automatic correction of hand movements could be driven by stereoscopic depth to occur in as early as 190 ms.This work was supported by the Grants from the National Natural Science Foundation of China (60970062 and 61173116) and the Doctoral Fund of Ministry of Education of China (20110072110014)

    On the Use of Quantum Algebras in Rotation-Vibration Spectroscopy

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    A two-parameter deformation of the Lie algebra u2_2 is used, in conjunction with the rotor system and the oscillator system, to generate a model for rotation-vibration spectroscopy of molecules and nuclei.Comment: 10 pages, Latex File, published in Modern Group Theoretical Methods in Physics, J. Bertrand et al. (eds.), Kluwer Academic Publishers (1995), 27-3

    Vocation, Belongingness, and Balance: A Qualitative Study of Veterinary Student Well-Being

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    An elevated risk for suicide among veterinarians has stimulated research into the mental health of the veterinary profession, and more recently attention has turned to the veterinary student population. This qualitative study sought to explore UK veterinary students' perceptions and experiences of university life, and to consider how these may affect well-being. Semi-structured interviews were conducted with 18 students from a single UK school who were purposively selected to include perspectives from male, female, graduate-entry, standard-entry (straight from high school), and widening participation students across all 5 years of the program. Three main themes were identified: a deep-rooted vocation, navigating belongingness, and finding balance. Participants described a long-standing goal of becoming a veterinarian, with a determination reflected by often circuitous routes to veterinary school and little or no consideration of alternatives. Although some had been motivated by a love of animals, others were intrinsically interested in the scientific and problem-solving challenges of veterinary medicine. Most expressed strong feelings of empathy with animal owners. The issue of belongingness was central to participants' experiences, with accounts reflecting their efforts to negotiate a sense of belongingness both in student and professional communities. Participants also frequently expressed a degree of acceptance of poor balance between work and relaxation, with indications of a belief that this imbalance could be rectified later. This study helps highlight future avenues for research and supports initiatives aiming to nurture a sense of collegiality among veterinary students as they progress through training and into the profession

    Language motivation in a reconfigured Europe: access, identity, autonomy

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    In this paper, I propose that we need to develop an appropriate set of conceptual tools for examining motivational issues pertaining to linguistic diversity, mobility and social integration in a rapidly changing and expanding Europe. I begin by drawing on research that has begun to reframe the concept of integrative motivation in the context of theories of self and identity. Expanding the notion of identity, I discuss the contribution of the Council of Europe's European Language Portfolio in promoting a view of motivation as the development of a plurilingual European identity and the enabling of access and mobility across a multilingual Europe. Next, I critically examine the assumption that the individual pursuit of a plurilingual identity is unproblematic, by highlighting the social context in which motivation and identity are constructed and embedded. To illuminate the role of this social context, I explore three inter-related theoretical frameworks: poststructuralist perspectives on language motivation as 'investment'; sociocultural theory; and theories of autonomy in language education. I conclude with the key message that, as with autonomy, language motivation today has an inescapably political dimension of which we need to take greater account in our research and pedagogical practice

    Genetic contributions to visuospatial cognition in Williams syndrome: insights from two contrasting partial deletion patients

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    Background Williams syndrome (WS) is a rare neurodevelopmental disorder arising from a hemizygotic deletion of approximately 27 genes on chromosome 7, at locus 7q11.23. WS is characterised by an uneven cognitive profile, with serious deficits in visuospatial tasks in comparison to relatively proficient performance in some other cognitive domains such as language and face processing. Individuals with partial genetic deletions within the WS critical region (WSCR) have provided insights into the contribution of specific genes to this complex phenotype. However, the combinatorial effects of different genes remain elusive. Methods We report on visuospatial cognition in two individuals with contrasting partial deletions in the WSCR: one female (HR), aged 11 years 9 months, with haploinsufficiency for 24 of the WS genes (up to GTF2IRD1), and one male (JB), aged 14 years 2 months, with the three most telomeric genes within the WSCR deleted, or partially deleted. Results Our in-depth phenotyping of the visuospatial domain from table-top psychometric, and small- and large-scale experimental tasks reveal a profile in HR in line with typically developing controls, albeit with some atypical features. These data are contrasted with patient JB’s atypical profile of strengths and weaknesses across the visuospatial domain, as well as with more substantial visuospatial deficits in individuals with the full WS deletion. Conclusions Our findings point to the contribution of specific genes to spatial processing difficulties associated with WS, highlighting the multifaceted nature of spatial cognition and the divergent effects of genetic deletions within the WSCR on different components of visuospatial ability. The importance of general transcription factors at the telomeric end of the WSCR, and their combinatorial effects on the WS visuospatial phenotype are also discussed
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