448 research outputs found

    NHS top managers, knowledge exchange and leadership: the early development of Academic Health Science Networks – a mixed-methods study

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    This study explored knowledge networking and leadership in the context of the early development of Academic Health Science Networks in England and made recommendations for future research

    Feasibility and Effectiveness of Using Wearable Activity Trackers in Youth: A Systematic Review

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    Background: The proliferation and popularity of wearable activity trackers (eg, Fitbit, Jawbone, Misfit) may present an opportunity to integrate such technology into physical activity interventions. While several systematic reviews have reported intervention effects of using wearable activity trackers on adults’ physical activity levels, none to date have focused specifically on children and adolescents.Objective: The aim of this review was to examine the effectiveness of wearable activity trackers as a tool for increasing children’s and adolescents’ physical activity levels. We also examined the feasibility of using such technology in younger populations (age range 5-19 years).Methods: We conducted a systematic search of 5 electronic databases, reference lists, and personal archives to identify articles published up until August 2016 that met the inclusion criteria. Articles were included if they (1) specifically examined the use of a wearable device within an intervention or a feasibility study; (2) included participants aged 5-19 years old; (3) had a measure of physical activity as an outcome variable for intervention studies; (4) reported process data concerning the feasibility of the device in feasibility studies; and (5) were published in English. Data were analyzed in August 2016.Results: In total, we identified and analyzed 5 studies (3 intervention, 2 feasibility). Intervention delivery ranged from 19 days to 3 months, with only 1 study using a randomized controlled trial design. Wearable activity trackers were typically combined with other intervention approaches such as goal setting and researcher feedback. While intervention effects were generally positive, the reported differences were largely nonsignificant. The feasibility studies indicated that monitor comfort and design and feedback features were important factors to children and adolescents.Conclusions: There is a paucity of research concerning the effectiveness and feasibility of wearable activity trackers as a tool for increasing children’s and adolescents’ physical activity levels. While there are some preliminary data to suggest these devices may have the potential to increase activity levels through self-monitoring and goal setting in the short term, more research is needed to establish longer-term effects on behavior

    Differentiation Between Women With Vulvovaginal Symptoms Who are Positive or Negative for Candida Species by Culture

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    Objective: To investigate whether clinical criteria could differentiate between women with vulvovaginitis who were culture positive or negative for vaginal Candida species. Methods: Vulvovaginal specimens were obtained from 501 women with a vaginal discharge and/or pruritis. Clinical information and wet mount microscopy findings were obtained. All specimens were sent to a central laboratory for species identification. Results: A positive culture for Candida species was obtained from 364 (72.7%) of the specimens. C. albicans was identified in 86.4% of the positive cultures, followed by C. glabrata in 4.5%, C. parapsilosis in 3.9%, C. tropicalis in 2.7% and other Candida species in 1.4%.Women with a positive Candida culture had an increased utilization of oral contraceptives (26.1% vs. 16.8%, p = 0.02) and antibiotics (8.2% vs. 0.7%, p = 0.001), and were more likely to be pregnant (9.1% vs. 3.6%, p = 0.04) than the culture-negative women. Dyspareunia was more frequent in women without Candida (38.0% vs. 28.3%, p = 0.03) while vaginal erythema (p = 0.01) was more common in women with a positive Candida culture. Conclusions: Although quantitative differences were observed, the presence of vaginal Candida vulvovaginitis cannot be definitively identified by clinical criteria

    Prehistory of Transit Searches

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    Nowadays the more powerful method to detect extrasolar planets is the transit method. We review the planet transits which were anticipated, searched, and the first ones which were observed all through history. Indeed transits of planets in front of their star were first investigated and studied in the solar system. The first observations of sunspots were sometimes mistaken for transits of unknown planets. The first scientific observation and study of a transit in the solar system was the observation of Mercury transit by Pierre Gassendi in 1631. Because observations of Venus transits could give a way to determine the distance Sun-Earth, transits of Venus were overwhelmingly observed. Some objects which actually do not exist were searched by their hypothetical transits on the Sun, as some examples a Venus satellite and an infra-mercurial planet. We evoke the possibly first use of the hypothesis of an exoplanet transit to explain some periodic variations of the luminosity of a star, namely the star Algol, during the eighteen century. Then we review the predictions of detection of exoplanets by their transits, those predictions being sometimes ancient, and made by astronomers as well as popular science writers. However, these very interesting predictions were never published in peer-reviewed journals specialized in astronomical discoveries and results. A possible transit of the planet beta Pic b was observed in 1981. Shall we see another transit expected for the same planet during 2018? Today, some studies of transits which are connected to hypothetical extraterrestrial civilisations are published in astronomical refereed journals. Some studies which would be classified not long ago as science fiction are now considered as scientific ones.Comment: Submiited to Handbook of Exoplanets (Springer

    Drought rewires the cores of food webs

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    Droughts are intensifying across the globe, with potentially devastating implications for freshwater ecosystems. We used new network science approaches to investigate drought impacts on stream food webs and explored potential consequences for web robustness to future perturbations. The substructure of the webs was characterized by a core of richly connected species surrounded by poorly connected peripheral species. Although drought caused the partial collapse of the food webs, the loss of the most extinction-prone peripheral species triggered a substantial rewiring of interactions within the networks’ cores. These shifts in species interactions in the core conserved the underlying core/periphery substructure and stability of the drought-impacted webs. When we subsequently perturbed the webs by simulating species loss in silico, the rewired drought webs were as robust as the larger, undisturbed webs. Our research unearths previously unknown compensatory dynamics arising from within the core that could underpin food web stability in the face of environmental perturbations

    Computations and Measurements of the Magnetic Polarizability Tensor Characterisation of Highly Conducting and Magnetic Objects

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    PurposeThe ability to characterise highly conducting objects, that may also be highly magnetic, by the complex symmetric rank–2 magnetic polarizability tensor (MPT) is important for metal detection applications including discriminating between threat and non-threat objects in security screening, identifying unexploded anti-personnel landmines and ordnance and identifying metals of high commercial value in scrap sorting. Many everyday non-threat items have both a large electrical conductivity and a magnetic behaviour, which, for sufficiently weak fields and the frequencies of interest, can be modelled by a high relative magnetic permeability. This paper aims to discuss the aforementioned idea.Design/methodology/approachThe numerical simulation of the MPT for everyday non-threat highly conducting magnetic objects over a broad range of frequencies is challenging due to the resulting thin skin depths. The authors address this by employing higher order edge finite element discretisations based on unstructured meshes of tetrahedral elements with the addition of thin layers of prismatic elements. Furthermore, computer aided design (CAD) geometrical models of the non-threat and threat object are often not available and, instead, the authors extract the geometrical features of an object from an imaging procedure.FindingsThe authors obtain accurate numerical MPT characterisations that are in close agreement with experimental measurements for realistic physical objects. The assessment of uncertainty shows the impact of geometrical and material parameter uncertainties on the computational results.Originality/valueThe authors present novel computations and measurements of MPT characterisations of realistic objects made of magnetic materials. A novel assessment of uncertainty in the numerical predictions of MPT characterisations for uncertain geometry and material parameters is included

    The Complete Multipartite Genome Sequence of Cupriavidus necator JMP134, a Versatile Pollutant Degrader

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    BACKGROUND: Cupriavidus necator JMP134 is a Gram-negative beta-proteobacterium able to grow on a variety of aromatic and chloroaromatic compounds as its sole carbon and energy source. METHODOLOGY/PRINCIPAL FINDINGS: Its genome consists of four replicons (two chromosomes and two plasmids) containing a total of 6631 protein coding genes. Comparative analysis identified 1910 core genes common to the four genomes compared (C. necator JMP134, C. necator H16, C. metallidurans CH34, R. solanacearum GMI1000). Although secondary chromosomes found in the Cupriavidus, Ralstonia, and Burkholderia lineages are all derived from plasmids, analyses of the plasmid partition proteins located on those chromosomes indicate that different plasmids gave rise to the secondary chromosomes in each lineage. The C. necator JMP134 genome contains 300 genes putatively involved in the catabolism of aromatic compounds and encodes most of the central ring-cleavage pathways. This strain also shows additional metabolic capabilities towards alicyclic compounds and the potential for catabolism of almost all proteinogenic amino acids. This remarkable catabolic potential seems to be sustained by a high degree of genetic redundancy, most probably enabling this catabolically versatile bacterium with different levels of metabolic responses and alternative regulation necessary to cope with a challenging environment. From the comparison of Cupriavidus genomes, it is possible to state that a broad metabolic capability is a general trait for Cupriavidus genus, however certain specialization towards a nutritional niche (xenobiotics degradation, chemolithoautotrophy or symbiotic nitrogen fixation) seems to be shaped mostly by the acquisition of "specialized" plasmids. CONCLUSIONS/SIGNIFICANCE: The availability of the complete genome sequence for C. necator JMP134 provides the groundwork for further elucidation of the mechanisms and regulation of chloroaromatic compound biodegradation

    Identification of metallic objects using spectral MPT signatures: object characterisation and invariants

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    The early detection of terrorist threat objects, such as guns and knives, through improved metal detection, has the potential to reduce the number of attacks and improve public safety and security. To achieve this, there is considerable potential to use the felds applied and measured by a metal detector to discriminate between different shapes and different metals since, hidden within the field perturbation, is object characterisation information. The magnetic polarizability tensor (MPT) offers an economical characterisation of metallic objects that can be computed for different threat and non-threat objects and has an established theoretical background, which shows that the induced voltage is a function of the hidden object's MPT coeffcients. In this paper, we describe the additional characterisation information that measurements of the induced voltage over a range of frequencies offer compared to measurements at a single frequency. We call such object characterisations its MPT spectral signature. Then, we present a series of alternative rotational invariants for the purpose of classifying hidden objects using MPT spectral signatures. Finally, we include examples of computed MPT spectral signature characterisations of realistic threat and non-threat objects that can be used to train machine learning algorithms for classification purposes

    Transient changes during microwave ablation simulation : a comparative shape analysis.

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    Microwave ablation therapy is a hyperthermic treatment for killing cancerous tumours whereby microwave energy is dispersed into a target tissue region. Modelling can provide a prediction for the outcome of ablation, this paper explores changes in size and shape of temperature and Specific absorption rate fields throughout the course of simulated treatment with different probe concepts. Here, an axisymmetric geometry of a probe embedded within a tissue material is created, solving coupled electromagnetic and bioheat equations using the finite element method, utilizing hp discretisation with the NGSolve library. Results show dynamic changes across all metrics, with different responses from different probe concepts. The sleeve probe yielded the most circular specific absorption rate pattern with circularity of 0.81 initially but suffered the largest reduction throughout ablation. Similarly, reflection coefficients differ drastically from their initial values, with the sleeve probe again experiencing the largest change, suggesting that it is the most sensitive the changes in the tissue dielectric properties in these select probe designs. These collective characteristic observations highlight the need to consider dielectric property changes and probe specific responses during the design cycle
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