4,898 research outputs found

    Automatic Detection of Seizures with Applications

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    There are an estimated two million people with epilepsy in the United States. Many of these people do not respond to anti-epileptic drug therapy. Two devices can be developed to assist in the treatment of epilepsy. The first is a microcomputer-based system designed to process massive amounts of electroencephalogram (EEG) data collected during long-term monitoring of patients for the purpose of diagnosing seizures, assessing the effectiveness of medical therapy, or selecting patients for epilepsy surgery. Such a device would select and display important EEG events. Currently many such events are missed. A second device could be implanted and would detect seizures and initiate therapy. Both of these devices require a reliable seizure detection algorithm. A new algorithm is described. It is believed to represent an improvement over existing seizure detection algorithms because better signal features were selected and better standardization methods were used

    An extended view of the Pisces Overdensity from the SCUSS survey

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    SCUSS is a u-band photometric survey covering about 4000 square degree of the South Galactic Cap, reaching depths of up to 23 mag. By extending around 1.5 mag deeper than SDSS single-epoch u data, SCUSS is able to probe much a larger volume of the outer halo, i.e. with SCUSS data blue horizontal branch (BHB) stars can trace the outer halo of the Milky Way as far as 100-150 kpc. Utilizing this advantage we combine SCUSS u band with SDSS DR9 gri photometric bands to identify BHB stars and explore halo substructures. We confirm the existence of the Pisces overdensity, which is a structure in the outer halo (at around 80 kpc) that was discovered using RR Lyrae stars. For the first time we are able to determine its spatial extent, finding that it appears to be part of a stream with a clear distance gradient. The stream, which is ~5 degrees wide and stretches along ~25 degrees, consists of 20-30 BHBs with a total significance of around 6sigma over the background. Assuming we have detected the entire stream and that the progenitor has fully disrupted, then the number of BHBs suggests the original system was similar to smaller classical or a larger ultra-faint dwarf galaxy. On the other hand, if the progenitor still exists, it can be hunted for by reconstructing its orbit from the distance gradient of the stream. This new picture of the Pisces overdensity sheds new light on the origin of this intriguing system.Comment: 8 pages, 4 figures, accepted by Ap

    The ATLAS tile calorimeter digitizer

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    The ATLAS Tile Calorimeter digitizer system samples photomultiplier signals from the scintillating tiles of the hadronic calorimeter. For each channel a pair of 10-bit ADCs digitize high and low gain signals at 40.08 MHz to provide the necessary 16-bit dynamic range. The sampled data is temporarily stored in digital pipelines for up to 6.375 \mu­s, awaiting a level-1 accept. For each accept received, the corresponding sampled pulse is transferred to a derandomizer buffer for subsequent readout to the data acquisition system (DAQ). The main functionality of the digitizer is implemented in radiation tolerant ASICs, using a fault tolerant architecture to minimize the consequences of radiation induced faults

    The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: selecting emission line galaxies using the Fisher discriminant

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    We present a new selection technique of producing spectroscopic target catalogues for massive spectroscopic surveys for cosmology. This work was conducted in the context of the extended Baryon Oscillation Spectroscopic Survey (eBOSS), which will use ~200 000 emission line galaxies (ELGs) at 0.6<zspec<1.0 to obtain a precise baryon acoustic oscillation measurement. Our proposed selection technique is based on optical and near-infrared broad-band filter photometry. We used a training sample to define a quantity, the Fisher discriminant (linear combination of colours), which correlates best with the desired properties of the target: redshift and [OII] flux. The proposed selections are simply done by applying a cut on magnitudes and this Fisher discriminant. We used public data and dedicated SDSS spectroscopy to quantify the redshift distribution and [OII] flux of our ELG target selections. We demonstrate that two of our selections fulfil the initial eBOSS/ELG redshift requirements: for a target density of 180 deg^2, ~70% of the selected objects have 0.6<zspec<1.0 and only ~1% of those galaxies in the range 0.6<zspec<1.0 are expected to have a catastrophic zspec estimate. Additionally, the stacked spectra and stacked deep images for those two selections show characteristic features of star-forming galaxies. The proposed approach using the Fisher discriminant could, however, be used to efficiently select other galaxy populations, based on multi-band photometry, providing that spectroscopic information is available. This technique could thus be useful for other future massive spectroscopic surveys such as PFS, DESI, and 4MOST.Comment: Version published in A&

    Time spent with cats is never wasted: Lessons learned from feline acromegalic cardiomyopathy, a naturally occurring animal model of the human disease

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    <div><p>Background</p><p>In humans, acromegaly due to a pituitary somatotrophic adenoma is a recognized cause of increased left ventricular (LV) mass. Acromegalic cardiomyopathy is incompletely understood, and represents a major cause of morbidity and mortality. We describe the clinical, echocardiographic and histopathologic features of naturally occurring feline acromegalic cardiomyopathy, an emerging disease among domestic cats.</p><p>Methods</p><p>Cats with confirmed hypersomatotropism (IGF-1>1000ng/ml and pituitary mass; n = 67) were prospectively recruited, as were two control groups: diabetics (IGF-1<800ng/ml; n = 24) and healthy cats without known endocrinopathy or cardiovascular disease (n = 16). Echocardiography was performed in all cases, including after hypersomatotropism treatment where applicable. Additionally, tissue samples from deceased cats with hypersomatotropism, hypertrophic cardiomyopathy and age-matched controls (n = 21 each) were collected and systematically histopathologically reviewed and compared.</p><p>Results</p><p>By echocardiography, cats with hypersomatotropism had a greater maximum LV wall thickness (6.5mm, 4.1–10.1mm) than diabetic (5.9mm, 4.2–9.1mm; Mann Whitney, p<0.001) or control cats (5.2mm, 4.1–6.5mm; Mann Whitney, p<0.001). Left atrial diameter was also greater in cats with hypersomatotropism (16.6mm, 13.0–29.5mm) than in diabetic (15.4mm, 11.2–20.3mm; Mann Whitney, p<0.001) and control cats (14.0mm, 12.6–17.4mm; Mann Whitney, p<0.001). After hypophysectomy and normalization of IGF-1 concentration (n = 20), echocardiographic changes proved mostly reversible. As in humans, histopathology of the feline acromegalic heart was dominated by myocyte hypertrophy with interstitial fibrosis and minimal myofiber disarray.</p><p>Conclusions</p><p>These results demonstrate cats could be considered a naturally occurring model of acromegalic cardiomyopathy, and as such help elucidate mechanisms driving cardiovascular remodeling in this disease.</p></div

    PEPSI: The high-resolution echelle spectrograph and polarimeter for the Large Binocular Telescope

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    PEPSI is the bench-mounted, two-arm, fibre-fed and stabilized Potsdam Echelle Polarimetric and Spectroscopic Instrument for the 2x8.4 m Large Binocular Telescope (LBT). Three spectral resolutions of either 43 000, 120 000 or 270 000 can cover the entire optical/red wavelength range from 383 to 907 nm in three exposures. Two 10.3kx10.3k CCDs with 9-{\mu}m pixels and peak quantum efficiencies of 96 % record a total of 92 echelle orders. We introduce a new variant of a wave-guide image slicer with 3, 5, and 7 slices and peak efficiencies between 96 %. A total of six cross dispersers cover the six wavelength settings of the spectrograph, two of them always simultaneously. These are made of a VPH-grating sandwiched by two prisms. The peak efficiency of the system, including the telescope, is 15% at 650 nm, and still 11% and 10% at 390 nm and 900 nm, respectively. In combination with the 110 m2 light-collecting capability of the LBT, we expect a limiting magnitude of 20th mag in V in the low-resolution mode. The R=120 000 mode can also be used with two, dual-beam Stokes IQUV polarimeters. The 270 000-mode is made possible with the 7-slice image slicer and a 100- {\mu}m fibre through a projected sky aperture of 0.74", comparable to the median seeing of the LBT site. The 43000-mode with 12-pixel sampling per resolution element is our bad seeing or faint-object mode. Any of the three resolution modes can either be used with sky fibers for simultaneous sky exposures or with light from a stabilized Fabry-Perot etalon for ultra-precise radial velocities. CCD-image processing is performed with the dedicated data-reduction and analysis package PEPSI-S4S. A solar feed makes use of PEPSI during day time and a 500-m feed from the 1.8 m VATT can be used when the LBT is busy otherwise. In this paper, we present the basic instrument design, its realization, and its characteristics

    Internal Color Properties of Resolved Spheroids in the Deep HST/ACS field of UGC 10214

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    (Abridged) We study the internal color properties of a morphologically selected sample of spheroidal galaxies taken from HST/ACS ERO program of UGC 10214 (``The Tadpole''). By taking advantage of the unprecedented high resolution of the ACS in this very deep dataset we are able to characterize spheroids at sub-arcseconds scales. Using the V_606W and I_814W bands, we construct V-I color maps and extract color gradients for a sample of spheroids at I_814W < 24 mag. We investigate the existence of a population of morphologically classified spheroids which show extreme variation in their internal color properties similar to the ones reported in the HDFs. These are displayed as blue cores and inverse color gradients with respect to those accounted from metallicity variations. Following the same analysis we find a similar fraction of early-type systems (~30%-40%) that show non-homologous internal colors, suggestive of recent star formation activity. We present two statistics to quantify the internal color variation in galaxies and for tracing blue cores, from which we estimate the fraction of non-homogeneous to homogeneous internal colors as a function of redshift up to z<1.2. We find that it can be described as about constant as a function of redshift, with a small increase with redshift for the fraction of spheroids that present strong color dispersions. The implications of a constant fraction at all redshifts suggests the existence of a relatively permanent population of evolving spheroids up to z~1. We discuss the implications of this in the context of spheroidal formation.Comment: Fixed URL for high resolution version. 13 Pages, 10 Figures. Accepted for Publication in ApJ. Sep 1st issue. Higher resolution version and complete table3B at http://acs.pha.jhu.edu/~felipe/e-prints/Tadpol

    Emerging communities of child-healthcare practice in the management of long-term conditions such as chronic kidney disease: Qualitative study of parents' accounts

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    Background: Parents of children and young people with long-term conditions who need to deliver clinical care to their child at home with remote support from hospital-based professionals, often search the internet for care-giving information. However, there is little evidence that the information available online was developed and evaluated with parents or that it acknowledges the communities of practice that exist as parents and healthcare professionals share responsibility for condition management. Methods. The data reported here are part of a wider study that developed and tested a condition-specific, online parent information and support application with children and young people with chronic-kidney disease, parents and professionals. Semi-structured interviews were conducted with 19 fathers and 24 mothers who had recently tested the novel application. Data were analysed using Framework Analysis and the Communities of Practice concept. Results: Evolving communities of child-healthcare practice were identified comprising three components and several sub components: (1) Experiencing (parents making sense of clinical tasks) through Normalising care, Normalising illness, Acceptance & action, Gaining strength from the affected child and Building relationships to formalise a routine; (2) Doing (Parents executing tasks according to their individual skills) illustrated by Developing coping strategies, Importance of parents' efficacy of care and Fear of the child's health failing; and (3) Belonging/Becoming (Parents defining task and group members' worth and creating a personal identity within the community) consisting of Information sharing, Negotiation with health professionals and Achieving expertise in care. Parents also recalled factors affecting the development of their respective communities of healthcare practice; these included Service transition, Poor parent social life, Psycho-social affects, Family chronic illness, Difficulty in learning new procedures, Shielding and avoidance, and Language and cultural barriers. Health care professionals will benefit from using the communities of child-healthcare practice model when they support parents of children with chronic kidney disease. Conclusions: Understanding some of the factors that may influence the development of communities of child-healthcare practice will help professionals to tailor information and support for parents learning to manage their child's healthcare. Our results are potentially transferrable to professionals managing the care of children and young people with other long-term conditions. © 2014 Carolan et al.; licensee BioMed Central Ltd
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