1,302 research outputs found

    Spontaneous self-ordered states of vortex-antivortex pairs in a Polariton Condensate

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    Polariton condensates have proved to be model systems to investigate topological defects, as they allow for direct and non-destructive imaging of the condensate complex order parameter. The fundamental topological excitations of such systems are quantized vortices. In specific configurations, further ordering can bring the formation of vortex lattices. In this work we demonstrate the spontaneous formation of ordered vortical states, consisting in geometrically self-arranged vortex-antivortex pairs. A mean-field generalized Gross-Pitaevskii model reproduces and supports the physics of the observed phenomenology

    Exploring the psychological rewards of a familiar semirural landscape: connecting to local nature through a mindful approach

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    This study analyses a 53,000 word diary of a year engaging with nature through over 200 trips to a semi-rural landscape. Thematic analysis revealed two themes; the transition from observer to nature connectedness and the ways in which the natural environment was experienced once a connection was made. These themes are discussed in relation to theories that seek to explain the positive effect of nature and nature connectedness. The findings are important as they suggest that repeated engagement with local semi-rural countryside can lead to a mindful approach and psychological rewards that do not require travel into the wilderness. The work informs further research into outcomes and processes of nature based interventions such as: trip frequency, duration and diary keeping

    Early careers on ecohydraulics:Challenges, opportunities and future directions

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    Early career researchers (ECRs) play a critical role in our knowledge-based society, yet they are the most vulnerable group in the scientific community. As a young, interdisciplinary science, ecohydraulics is particularly reliant on ECRs for future progress. In 2014, the Early Careers on Ecohydraulics Network (ECoENet) was created to help the development of young researchers in this field. In this paper, we synthesize the outcomes of a workshop for ECRs organized by ECoENet in February 2016. We aim to show how the potential of ECRs can be maximized to drive progress in ecohydraulics. According to the most recent entrants to the field, major challenges lie in becoming more integrated as a discipline, developing a common vocabulary and a collective vision, engaging effectively with policy-makers, and encouraging public participation. ECRs need to develop their careers on an international scale in a way that crosses traditional disciplinary boundaries, including the social sciences, and allows them time to work at fundamental levels rather than focusing solely on individual applications. We propose a strategy to facilitate this by providing: a platform for disseminating research; an international support network; and a set of services for enhancing ECR training and experience. Early career researchers; interdisciplinary science; ecohydraulics; society; ecology; hydraulicsacceptedVersio

    Quantitative Magnetic Resonance Imaging Analysis of the Cervical Spine Extensor Muscles: Intrarater and Interrater Reliability of a Novice and an Experienced Rater

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    Study DesignReliability study.PurposeTo examine the reliability of novice and experienced raters for measurements of the size and composition of the cervical extensor muscles using a thresholding technique.Overview of LiteratureAlthough some authors have reported on the dependability of magnetic resonance imaging (MRI) measurements of the cervical muscles, there remains some variability regarding intrarater and interrater reliabilities, and few studies have examined the associated measurement error. Whether the rater's experience noticeably influences the reliability and precision of such measurements has also not been examined.MethodsA sample of 10 patients with cervical pathologies was selected. Muscle cross-sectional area (CSA), functional cross-sectional area (FCSA), and signal intensity of the cervical extensor muscles were acquired from axial T2-weighted MRIs by a novice and an experienced rater. All measurements were obtained twice, at least 5 days apart, while the raters were blinded to all earlier measurements.ResultsInterrater reliability estimates (intraclass correlation coefficients) varied between 0.84 and 0.99 for the novice rater and between 0.94 and 0.99 for the experienced rater, indicating excellent reliability. The standard error of measurement for the novice rater was, however, noticeably higher for all cervical muscle measurements. Most of the interrater estimates showed excellent agreement with the exception of CSA measurement of the semispinalis cervicis at C4–C7 and FCSA measurement of the multifidus and semispinalis cervicis at C4–C7, which showed poor interrater reliability.ConclusionsThe proposed method of investigating cervical muscle measurements was highly reliable; however, novice raters should receive adequate training before using this method for diagnostic, research, and clinical purposes

    Additional experimental evidence for a solar influence on nuclear decay rates

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    Additional experimental evidence is presented in support of the recent hypothesis that a possible solar influence could explain fluctuations observed in the measured decay rates of some isotopes. These data were obtained during routine weekly calibrations of an instrument used for radiological safety at The Ohio State University Research Reactor using Cl-36. The detector system used was based on a Geiger-Mueller gas detector, which is a robust detector system with very low susceptibility to environmental changes. A clear annual variation is evident in the data, with a maximum relative count rate observed in January/February, and a minimum relative count rate observed in July/August, for seven successive years from July 2005 to June 2011. This annual variation is not likely to have arisen from changes in the detector surroundings, as we show here.Comment: 8 pages, 6 figure

    Cystamine/cysteamine rescues the dopaminergic system and shows neurorestorative properties in an animal model of Parkinson's disease.

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    The neuroprotective properties of cystamine identified in pre-clinical studies have fast-tracked this compound to clinical trials in Huntington's disease, showing tolerability and benefits on motor symptoms. We tested whether cystamine could have such properties in a Parkinson's disease murine model and now provide evidence that it can not only prevent the neurodegenerative process but also can reverse motor impairments created by a 6-hydroxydopamine lesion 3weeks post-surgery. Importantly, we report that cystamine has neurorestorative properties 5weeks post-lesion as seen on the number of nigral dopaminergic neurons which is comparable with treatments of cysteamine, the reduced form of cystamine used in the clinic, as well as rasagiline, increasingly prescribed in early parkinsonism. All three compounds induced neurite arborization of the remaining dopaminergic cells which was further confirmed in ex vivo dopaminergic explants derived from Pitx3-GFP mice. The disease-modifying effects displayed by cystamine/cysteamine would encourage clinical testing

    Postoperative Assessment of Pedicle Screws and Management of Breaches: A Survey among Canadian Spine Surgeons and a New Scoring System

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    Study DesignThis study was designed as a survey amongst Canadian spine surgeon to determine a scoring system to standardize pedicle screw placement assessment.PurposeThis study aimed to obtain and analyze the opinions of spine surgeons regarding the assessment of pedicle screw accuracy, with the goal of establishing clinical guidelines for interventions for malpositioned pedicle screws.Overview of LiteratureAccurate placement of pedicle screws is challenging, and misalignment can lead to various complications. To date, there is no recognized gold standard for assessing pedicle screw placement accuracy. The literature is lacking studies attempting to standardize pedicle screw placement accuracy assessment.MethodsA survey of the clinical methods and imaging criteria that are used for assessing pedicle screw placement accuracy was designed and sent to orthopedic and neurosurgery spine surgeons from the Canadian Spine Society for their anonymous participation.ResultsThirty-five surgeons completed the questionnaire. The most commonly used modalities for assessing pedicle screw position postoperatively were plain X-rays (97%) and computed tomography (CT, 97%). In both symptomatic and asymptomatic patients, the most and least worrisome breaches were medial and anterior breaches, respectively. The majority of surgeons tended not to re-operate on asymptomatic breaches. More than 60% of surgeons would re-operate on patients with new-onset pain and a ≤4-mm medial or inferior breach in both thoracic and lumbar regions. If a patient experienced sensory loss and a breach on CT, in either the thoracic or lumbar levels, 90% and 70% of the surgeons would re-operate for a medial breach and an inferior breach, respectively.ConclusionsPostoperative clinical presentation and imaging findings are crucial for interpreting aberrant pedicle screw placement. This study presents a preliminary scoring system for standardizing the classification of pedicle screws
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