7,486 research outputs found

    On giant piezoresistance effects in silicon nanowires and microwires

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    The giant piezoresistance (PZR) previously reported in silicon nanowires is experimentally investigated in a large number of surface depleted silicon nano- and micro-structures. The resistance is shown to vary strongly with time due to electron and hole trapping at the sample surfaces. Importantly, this time varying resistance manifests itself as an apparent giant PZR identical to that reported elsewhere. By modulating the applied stress in time, the true PZR of the structures is found to be comparable with that of bulk silicon

    Emergent charge ordering in near half doped Na0.46_{0.46}CoO2_{2}

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    We have utilized neutron powder diffraction to probe the crystal structure of layered Nax_{x}CoO2_{2} near the half doping composition of x=x=0.46 over the temperature range of 2 to 600K. Our measurements show evidence of a dynamic transition in the motion of Na-ions at 300K which coincides with the onset of a near zero thermal expansion in the in-plane lattice constants. The effect of the Na-ordering on the CoO2_{2} layer is reflected in the octahedral distortion of the two crystallographically inequivalent Co-sites and is evident even at high temperatures. We find evidence of a weak charge separation into stripes of Co+3.5+Ï”^{+3.5+\epsilon} and Co+3.5−ϔ^{+3.5-\epsilon}, ϔ∌0.06e\epsilon\sim0.06e below \Tco=150K. We argue that changes in the Na(1)-O bond lengths observed at the magnetic transition at \tm=88K reflect changes in the electronic state of the CoO2_{2} layerComment: 7 pages, 6 figures, in press Phys. Rev.

    A high-resolution radio survey of the Vela supernova remnant

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    This paper presents a high-resolution radio continuum (843 MHz) survey of the Vela supernova remnant. The contrast between the structures in the central pulsar-powered nebula of the remnant and the synchrotron radiation shell allows the remnant to be identified morphologically as a member of the composite class. The data are the first of a composite remnant at spatial scales comparable with those available for the Cygnus Loop and the Crab Nebula, and make possible a comparison of radio, optical and soft X-ray emission from the resolved shell filaments. The survey, made with the Molonglo Observatory Synthesis Telescope, covers an area of 50 square degrees at a resolution of 43'' x 60'', while imaging structures on scales up to 30'.Comment: 18 pages, 7 jpg figures (version with ps figures at http://astro.berkeley.edu/~dbock/papers/); AJ, in pres

    Exploring female dancer’s emotions and coping experiences following deselection:An interpretative phenomenological analysis

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    Objectives: The purpose of this study was to (a) explore female dancers’ experiences of emotions following deselection and (b) examine the coping mechanisms used by dancers to overcome these emotions.Methods: Two one-on-one semi-structured interviews were conducted with ten female dancers (aged 20–26, average career length M = 6 years) from dance forms including ballet, jazz, commercial, and contemporary. Data were collected and analysed using interpretative phenomenological analysis by Smith (2009).Results: Dancers experienced a rollercoaster of emotions including disappointment, confidence impacts, and embarrassment, as well as changes in their feelings towards dance. To deal with these emotions the dancers often avoided their emotions, used dance as therapy, and sought social support as coping mechanisms.Conclusions: Dancers’ emotional experiences of deselection seem to negatively influence the social identities of the dancer and the levels of motivation they held towards dance. Findings highlighted the importance of coping with these emotions, and suggested future sport psychologists should apply interventions to assist with this and the regulation of emotions to prevent dancers from dropping out

    Results from the third Scottish National Prevalence Survey: is a population health approach now needed to prevent healthcare-associated infections?

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    Summary Background Healthcare associated infections (HAI) are a major public health concern and a significant cause of morbidity and mortality. A robust and current evidence base that is specific to local, national and Europe-wide settings is necessary to inform the development of strategies to reduce HAI and contain antimicrobial resistance (AMR). Aim To measure the prevalence of HAI and antimicrobial prescribing and identify key priority areas for interventions to reduce the burden of infection. Methods A national rolling PPS in National Health Service (NHS) acute, NHS non-acute, NHS paediatric and independent hospitals was carried out between September and November 2016 using the European Centre for Disease Prevention and Control protocol designed for the European PPS. Findings The prevalence of HAI was 4.6%, 2.7% and 3.2% in acute adults, paediatric and non-acute patient groups, respectively. The most common HAI types reported in adult patients were urinary tract infection and pneumonia. The prevalence of antimicrobial prescribing was 35.7%, 29.3% and 13.8% in acute adults, paediatric and non-acute patient groups, respectively. Respiratory, skin and soft tissue, gastrointestinal and urinary tract infections were the most common infections being treated at the time of survey. Conclusion HAI continues to be a public health concern in Scotland. UTI and pneumonia continue to place a significant burden on patients and on healthcare delivery, including those that develop in the community and require hospital admission. A broader population health approach which focuses on reducing the risk of infection upstream would reduce these infections in both community and hospital settings

    Late Light Curves of Normal Type Ia Supernovae

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    We present late-epoch optical photometry (BVRI) of seven normal/super-luminous Type Ia supernovae: SN 2000E, SN 2000ce, SN 2000cx, SN 2001C, SN 2001V, SN 2001bg, SN 2001dp. The photometry of these objects was obtained using a template subtraction method to eliminate galaxy light contamination during aperture photometry. We show the optical light curves of these supernovae out to epochs of up to ~640 days after the explosion of the supernova. We show a linear decline in these data during the epoch of 200-500 days after explosion with the decline rate in the B,V,& R bands equal to about 1.4 mag/100 days, but the decline rate of the I-band is much shallower at 0.94 mag/100 days.Comment: 33 pages, 11 figures, Accepted for publication in The Astronomical Journa
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