2,555 research outputs found

    Recovering Solar Toroidal Field Dynamics From Sunspot Location Patterns

    Full text link
    We analyze both Kitt Peak magnetogram data and MDI continuum intensity sunspot data to search for the following solar toroidal band properties: width in latitude and the existence of a tipping instability (longitudinal m=1 mode) for any time during the solar cycle. To determine the extent which we can recover the toroidal field dynamics, we forward model artificially generated sunspot distributions from subsurface toroidal fields we assigned certain properties. We analyzed two sunspot distribution parameters using MDI and model data: the average latitudinal separation of sunspot pairs as a function of longitudinal separation, and the number of sunspot pairs creating a given angle with respect to the E-W direction. A toroidal band of 10 degrees width with a constant tipping of 5 degrees best fits MDI data early in the solar cycle. A toroidal band of 20 degrees width with a tipping amplitude decreasing in time from 5 to 0 degrees best fits MDI data late in the solar cycle. Model data generated by untipped toroidal bands cannot fit MDI high latitude data and can fit only one parameter at low latitudes. Tipped toroidal bands satisfy chi squared criteria at both high and low latitudes. We conclude this is evidence to reject the null hypothesis - that toroidal bands in the solar tachocline do not experience a tipping instability - in favor of the hypothesis that the toroidal band experiences an m=1 tipping instability. Our finding that the band widens from ~10 degrees early in the solar cycle to ~20 degrees late in the solar cycle may be explained in theory by magnetic drag spreading the toroidal band due to altered flow along the tipped field lines.Comment: This paper is accepted to Astrophysical Journal, September 2005 issu

    Gated metabolic myocardial imaging, a surrogate for dual perfusion-metabolism imaging by positron emission tomography

    Get PDF
    Acknowledgments The authors are grateful for the help from Dr H Ali and Dr A Dawson. Funding: This study was performed using a research grant from the Aberdeen Royal Hospitals Trust's Endowment Fund, with further support from the Department of Medical Physics at the University of Aberdeen, for which the authors express their gratitude.Peer reviewedPublisher PD

    Erratum to: Cosmogenic 10Be-derived denudation rates of the Eastern and Southern European Alps

    Get PDF
    Denudation rates from cosmogenic 10Be measured in quartz from recent river sediment have previously been used in the Central Alps to argue that rock uplift occurs through isostatic response to erosion in the absence of ongoing convergence. We present new basin-averaged denudation rates from large rivers in the Eastern and Southern European Alps together with a detailed topographic analysis in order to infer the forces driving erosion. Denudation rates in the Eastern and Southern Alps of 170-1,400mmky−1 are within a similar range to those in the Central Alps for similar lithologies. However, these denudation rates vary considerably with lithology, and their variability generally increases with steeper landscapes, where correlations with topographic metrics also become poorer. Tertiary igneous rocks are associated with steep hillslopes and channels and low denudation rates, whereas pre-Alpine gneisses usually exhibit steep hillslopes and higher denudation rates. Molasse, flysch, and schists display lower mean basin slopes and channel gradients, and, despite their high erodibility, low erosion rates. Exceptionally low denudation rates are also measured in Permian rhyolite, which has high mean basin slopes. We invoke geomorphic inheritance as a major factor controlling erosion, such that large erosive glaciers in the late Quaternary cold periods were more effective in priming landscapes in the Central Alps for erosion than in the interior Eastern Alps. However, the difference in tectonic evolution of the Eastern and Central Alps potentially adds to differences in their geomorphic response; their deep structures differ significantly and, unlike the Central Alps, the Eastern Alps are affected by ongoing tectonic influx due to the slow motion and rotation of Adria. The result is a complex pattern of high mountain erosion in the Eastern Alps, which has evolved from one confined to the narrow belt of the Tauern Window in late Tertiary time to one affecting the entire underthrust basement, orogenic lid, and parts of the Southern Alps toda

    The effect of relative plasma plume delay on the properties of complex oxide films grown by multi-laser multi-target combinatorial pulsed laser deposition

    No full text
    We report the effects of relative time delay of plasma plumes on thin garnet crystal films fabricated by dual-beam, combinatorial pulsed laser deposition. Relative plume delay was found to affect both the lattice constant and elemental composition of mixed Gd3Ga5O12 (GGG) and Gd3Sc2Ga5O12 (GSGG) films. Further analysis of the plasmas was undertaken using a Langmuir probe, which revealed that for relative plume delays shorter than ~200 µs, the second plume travels through a partial vacuum created by the first plume, leading to higher energy ion bombardment of the growing film. The resulting in-plane stresses are consistent with the transition to a higher value of lattice constant normal to the film plane that was observed around this delay value. At delays shorter than ~10 µs, plume propagation was found to overlap, leading to scattering of lighter ions from the plume and a change in stoichiometry of the resultant films

    Assessing the genetic diversity of rice originating from Bangladesh, Assam and West Bengal

    Get PDF
    Acknowledgements This work was funded by BBSRC research project BB/J00336/1. FS and a part of the proportion of the cost of the Illumina genotyping was funded by a Beachell-Borlag International Fellowship. The authors would like to acknowledge the help of Dr MK Sarmah in collecting seed samples of the landraces and improved cultivars from Assam used in this study and Dr. Ma. Elizabeth B. Naredo and Ms. Sheila Mae Q. Mercado for handling of IRGC accessions and preparation of DNAs for genotyping. All rice seeds used here were obtained with MTA agreements and seed and dry leaves imported into the UK under import licence IMP⁄SOIL⁄18⁄2009 issued by Science and Advice for Scottish Agriculture.Peer reviewedPublisher PD

    SCOPE: Safer care for older persons (in residential) environments: A study protocol

    Get PDF
    BACKGROUND: The current profile of residents living in Canadian nursing homes includes elder persons with complex physical and social needs. High resident acuity can result in increased staff workload and decreased quality of work life. AIMS: Safer Care for Older Persons [in residential] Environments is a two year (2010 to 2012) proof-of-principle pilot study conducted in seven nursing homes in western Canada. The purpose of the study is to evaluate the feasibility of engaging front line staff to use quality improvement methods to integrate best practices into resident care. The goals of the study are to improve the quality of work life for staff, in particular healthcare aides, and to improve residents' quality of life. METHODS/DESIGN: The study has parallel research and quality improvement intervention arms. It includes an education and support intervention for direct caregivers to improve the safety and quality of their care delivery. We hypothesize that this intervention will improve not only the care provided to residents but also the quality of work life for healthcare aides. The study employs tools adapted from the Institute for Healthcare Improvement's Breakthrough Series: Collaborative Model and Canada's Safer Healthcare Now! improvement campaign. Local improvement teams in each nursing home (1 to 2 per facility) are led by healthcare aides (non-regulated caregivers) and focus on the management of specific areas of resident care. Critical elements of the program include local measurement, virtual and face-to-face learning sessions involving change management, quality improvement methods and clinical expertise, ongoing virtual and in person support, and networking. DISCUSSION: There are two sustainability challenges in this study: ongoing staff and leadership engagement, and organizational infrastructure. Addressing these challenges will require strategic planning with input from key stakeholders for sustaining quality improvement initiatives in the long-term care sector
    corecore