3,036 research outputs found

    Ovine Progressive Pneumonia: A Brief Overview

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    Ovine progressive pneumonia (OPP), a chronic debilitating disease of adult sheep, develops insidiously over a long incubation period. The infection is widespread and may produce a fatal multisystemic lymphoproliferative disease. There is evidence that OPP virus infection is common in western and midwestern sheep flocks. A survey of cull ewes from western states revealed serological prevalence rates of up to 67 %. In Idaho, infection rates within range flocks were 51-90 %. A recent serological survey of the Iowa State University sheep flock indicated that 49 % of the ewes have opp virus antibodies and carry the virus

    驚くべき航海記と旅行記

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    A Critical Analysis of the Theoretical Basis of Ultrasonic Scattering Measurements

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    There are three elements involved in the backscattering from inhomogeneous media; the scattering properties of a single particle or scattering element, the scattering associated with a group of such particles and the relationship of the scattered wave to the measured signal. Ideally it should be possible to obtain information about the material microstructure from ultrasonic backscattering measurements. However, a number of assumptions and approximations must be made before the problem becomes tractable, and it is the purpose of the present investigation to compare the various approaches available in the literature in an attempt to quantify the errors involved with some of these approximations

    Maintenance Task Classification: Towards Automated Robotic Maintenance for Industry

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    AbstractThe business model of high-value capital assets is shifting from purchasing a physical product to acquiring a result or a function supported by the product combined with a number of related services. One such service, maintenance, is perhaps the most efficient way to keep the function available during the product lifecycle. Automation has played a vital role in industry throughout history, particularly within the production line. With the movement towards providing product service systems the need for services such as maintenance are increasingly important for a manufactured product, and the pull towards automation may drive down costs and improve performance time. Although currently robotic applications to maintenance beyond monitoring and inspection tasks are not common, this research aims at exploring the feasibility of future maintenance robots that can perform a variety of maintenance tasks. As its first step, this work looks first at investigation, cataloging and classification of a number of maintenance tasks using standard industrial engineering techniques such as time motion, method or workflow analysis. This involves decomposing the maintenance work into a number of ‘unit tasks’ required to be performed in order to accomplish the specified maintenance

    Mechanism of magnetisation relaxation in M III 2 Dy III 2 (M = Cr, Mn, Fe, Al) “butterfly” complexes: How important are the transition metal ions here?

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    We describe the synthesis, characterisation and magnetic studies of four tetranuclear, isostructural “butterfly” heterometallic complexes: [MIII 2 LnIII 2 (m3-OH)2(p-Me-PhCO2)6(L)2] (H2 L ¼ 2,20-((pyridin-2-ylmethyl)azanediyl)bis(ethan-1-ol), M ¼ Cr, Ln ¼ Dy (1), Y (2), M ¼ Mn, Ln ¼ Dy (3), Y (4)), which extend our previous study on the analogous 5 {Fe2Dy2}, 6 {Fe2Y2} and 7 {Al2Dy2} compounds. We also present data on the yttrium diluted 7 {Al2Dy2}: 8 {Al2Dy0.18Y1.82}. Compounds dc and ac magnetic susceptibility data reveal single-molecule magnet (SMM) behaviour for complex 3 {Mn2Dy2}, in the absence of an external magnetic field, with an anisotropy barrier Ueff of 19.2 K, while complex 1 {Cr2Dy2}, shows no ac signals even under applied dc field, indicating absence of SMM behaviour. The diluted sample 8 {Al2Dy0.18Y1.82} shows field induced SMM behaviour with an anisotropy barrier Ueff of 69.3 K. Furthermore, the theoretical magnetic properties of [MIII 2 LnIII 2 (m3-OH)2(p-Me-PhCO2)6(L)2] (M ¼ Cr, 1 or Mn, 3) and their isostructural complexes: [MIII 2 DyIII 2 (m3-OH)2(p-Me-PhCO2)6(L)2] (M ¼ Fe, 5 or Al, 7) are discussed and compared. To understand the experimental observations for this family, DFT and ab initio CASSCF + RASSI-SO calculations were performed. The experimental and theoretical calculations suggest that altering the 3dIII ions can affect the single-ion properties and the nature and the magnitude of the 3dIII–3dIII, 3dIII–DyIII and DyIII–DyIII magnetic coupling, thus quenching the quantum tunneling of magnetisation (QTM) significantly, thereby improving the SMM properties within this motif. This is the first systematic study looking at variation and therefore role of trivalent transition metal ions, as well as the diamgnetic AlIII ion, on slow relaxation of magnetisation within a series of isostructural 3d–4f butterfly compounds

    Safe and just operating spaces for regional social-ecological systems

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    Humanity faces a major global challenge in achieving wellbeing for all, while simultaneously ensuring that the biophysical processes and ecosystem services that underpin wellbeing are exploited within scientifically informed boundaries of sustainability. We propose a framework for defining the safe and just operating space for humanity that integrates social wellbeing into the original planetary boundaries concept (RockstrĂśm et al., 2009a,b) for application at regional scales. We argue that such a framework can: (1) increase the policy impact of the boundaries concept as most governance takes place at the regional rather than planetary scale; (2) contribute to the understanding and dissemination of complexity thinking throughout governance and policy-making; (3) act as a powerful metaphor and communication tool for regional equity and sustainability. We demonstrate the approach in two rural Chinese localities where we define the safe and just operating space that lies between an environmental ceiling and a social foundation from analysis of time series drawn from monitored and palaeoecological data, and from social survey statistics respectively. Agricultural intensification has led to poverty reduction, though not eradicated it, but at the expense of environmental degradation. Currently, the environmental ceiling is exceeded for degraded water quality at both localities even though the least well-met social standards are for available piped water and sanitation. The conjunction of these social needs and environmental constraints around the issue of water access and quality illustrates the broader value of the safe and just operating space approach for sustainable development

    Whole-Retina Reduced Electrophysiological Activity in Mice Bearing Retina-Specific Deletion of Vesicular Acetylcholine Transporter

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    Background: Despite rigorous characterization of the role of acetylcholine in retinal development, long-term effects of its absence as a neurotransmitter are unknown. One of the unanswered questions is how acetylcholine contributes to the functional capacity of mature retinal circuits. The current study investigates the effects of disrupting cholinergic signalling in mice, through deletion of vesicular acetylcholine transporter (VAChT) in the developing retina, pigmented epithelium, optic nerve and optic stalk, on electrophysiology and structure of the mature retina. Methods & Results A combination of electroretinography, optical coherence tomography imaging and histological evaluation assessed retinal integrity in mice bearing retina-targeted (embryonic day 12.5) deletion of VAChT (VAChT(Six3-Cre-flox/flox)) and littermate controls at 5 and 12 months of age. VAChT(Six3-Cre-flox/flox) mice did not show any gross changes in nuclear layer cellularity or synaptic layer thickness. However, VAChT(Six3-Cre-flox/flox) mice showed reduced electrophysiological response of the retina to light stimulus under scotopic conditions at 5 and 12 months of age, including reduced a-wave, b-wave, and oscillatory potential (OP) amplitudes and decreased OP peak power and total energy. Reduced a-wave amplitude was proportional to the reduction in b-wave amplitude and not associated with altered a-wave 10%-90% rise time or inner and outer segment thicknesses. Significance This study used a novel genetic model in the first examination of function and structure of the mature mouse retina with disruption of cholinergic signalling. Reduced amplitude across the electroretinogram wave form does not suggest dysfunction in specific retinal cell types and could reflect underlying changes in the retinal and/or extraretinal microenvironment. Our findings suggest that release of acetylcholine by VAChT is essential for the normal electrophysiological response of the mature mouse retina

    Buffered 1% Lidocaine With Epinephrine Can Be as Effective as Nonbuffered 2% Lidocaine With Epinephrine for Maxillary Field Block

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    Buffering local anesthetics with epinephrine (Epi) offers clinicians options not often considered. This study assessed outcomes for pulpal anesthesia, pain on injection, and time to midface numbness for buffered 1% lidocaine with 1:100,000 Epi versus nonbuffered 2% lidocaine with 1:100,000 Epi. In this trial with a randomized, crossover design, buffered 1% lidocaine was compared with nonbuffered 2% lidocaine. Subjects were adult volunteers who served as their own controls. The predictor variables were alternate drug formulations. The outcome variables were subjects' responses to cold and electric pulp testing (EPT) stimulation of the maxillary first molar and canine, pain levels during the injection, and time to midface numbness. After maxillary field blocks with 40 mg of buffered lidocaine or 80 mg of nonbuffered lidocaine, subjects reported pain on injection and responses of the maxillary first molar and canine after cold and EPT stimulation. Teeth were tested before field block and at 30-minute intervals until a positive response was detected. Two weeks later, subjects were tested with the alternate drug combinations. For all outcome variables, assessment of treatment difference, calculated as 1% buffered minus 2% nonbuffered, was performed with the Wilcoxon rank sum test with significance at P < .05. More of the 24 subjects were women and Caucasian. The median age was 23.5 years (interquartile range, 21, 25 years), and the median body weight was 155 lb (interquartile range, 128.5, 176.5 lb). Pain levels during the injection were significantly lower for 1% buffered lidocaine, with P = .04. Times to response after injection were not significantly different between the 2 drug formulations for the cold test on a molar, with P = .08, or the cold test on a canine, with P = .22. However, times to response were significantly longer for nonbuffered drugs for EPT on the molar and canine, both with P = .01. Buffering 1% lidocaine with 1:100,000 Epi reduces the pain on injection with a maxillary field block and results in similar lengths of pulpal anesthesia tested with a cold stimulus as compared with nonbuffered 2% lidocaine with 1:100,000 Epi

    Beam-Energy-Dependent Two-Pion Interferometry and the Freeze-Out Eccentricity of Pions Measured in Heavy Ion Collisions at the STAR Detector

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    We present results of analyses of two-pion interferometry in Au+Au collisions at √SNN=7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the BNL Relativistic Heavy Ion Collider Beam Energy Scan program. The extracted correlation lengths (Hanbury-Brown–Twiss radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model

    Jet Dipolarity: Top Tagging with Color Flow

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    A new jet observable, dipolarity, is introduced that can distinguish whether a pair of subjets arises from a color singlet source. This observable is incorporated into the HEPTopTagger and is shown to improve discrimination between top jets and QCD jets for moderate to high pT.Comment: 8 pages, 6 figures (updated to JHEP version
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