3,281 research outputs found

    Classification of journal surfaces using surface topography parameters and software methods to compensate for stylus geometry

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    Measurements made with a stylus surface tracer which provides a digitized representation of a surface profile are discussed. Parameters are defined to characterize the height (e.g., RMS roughness, skewness, and kurtosis) and length (e.g., autocorrelation) of the surface topography. These are applied to the characterization of crank shaft journals which were manufactured by different grinding and lopping procedures known to give significant differences in crank shaft bearing life. It was found that three parameters (RMS roughness, skewness, and kurtosis) are necessary to adequately distinguish the character of these surfaces. Every surface specimen has a set of values for these three parameters. They can be regarded as a set coordinate in a space constituted by three characteristics axes. The various journal surfaces can be classified along with the determination of a proper wavelength cutoff (0.25 mm) by using a method of separated subspace. The finite radius of the stylus used for profile tracing gives an inherent measurement error as it passes over the fine structure of the surface. A mathematical model is derived to compensate for this error

    Microwave scattering and emission properties of large impact craters on the surface of Venus

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    Many of the impact craters on Venus imaged by the Magellan synthetic aperture radar (SAR) have interior floors with oblique incidence angle backscatter cross sections 2 to 16 times (3 dB to 12 dB) greater than the average scattering properties of the planet's surface. Such high backscatter cross sections are indicative of a high degree of wavelength-scale surface roughness and/or a high intrinsic reflectivity of the material forming the crater floors. Fifty-three of these (radar) bright floored craters are associated with 93 percent of the parabolic-shaped radar-dark features found in the Magellan SAR and emissivity data, features that are thought to be among the youngest on the surface of Venus. It was suggested by Campbell et al. that either the bright floors of the parabolic feature parent craters are indicative of a young impact and the floor properties are modified with time to a lower backscatter cross section or that they result from some property of the surface or subsurface material at the point of impact or from the properties of the impacting object. As a continuation of earlier work we have examined all craters with diameters greater than 30 km (except 6 that were outside the available data) so both the backscatter cross section and emissivity of the crater floors could be estimated from the Magellan data

    Suspected Canine Zinc Toxicosis Caused by Ingestion of Pennies

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    A 21 pound, nine year old spayed female Shih Tzu was presented to the Oradell Animal Hospital at 3 a.m. on Sunday morning with a complaint of anorexia, lethargy and vomiting for the past two days. The dog\u27s previous medical history was unremarkable, except for being hit by a car in November 1983. A right ilial fracture sustained at that time had been plated. The animal was current on all routine vaccinations

    Trading interactions for topology in scale-free networks

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    Scale-free networks with topology-dependent interactions are studied. It is shown that the universality classes of critical behavior, which conventionally depend only on topology, can also be explored by tuning the interactions. A mapping, γ=(γμ)/(1μ)\gamma' = (\gamma - \mu)/(1-\mu), describes how a shift of the standard exponent γ\gamma of the degree distribution P(q)P(q) can absorb the effect of degree-dependent pair interactions Jij(qiqj)μJ_{ij} \propto (q_iq_j)^{-\mu}. Replica technique, cavity method and Monte Carlo simulation support the physical picture suggested by Landau theory for the critical exponents and by the Bethe-Peierls approximation for the critical temperature. The equivalence of topology and interaction holds for equilibrium and non-equilibrium systems, and is illustrated with interdisciplinary applications.Comment: 4 pages, 5 figure

    COMPTEL solar flare observations

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    COMPTEL as part of a solar target of opportunity campaign observed the sun during the period of high solar activity from 7-15 Jun. 1991. Major flares were observed on 9 and 11 Jun. Although both flares were large GOES events (greater than or = X10), they were not extraordinary in terms of gamma-ray emission. Only the decay phase of the 15 Jun. flare was observed by COMPTEL. We report the preliminary analysis of data from these flares, including the first spectroscopic measurement of solar flare neutrons. The deuterium formation line at 2.223 MeV was present in both events and for at least the 9 Jun. event, was comparable to the flux in the nuclear line region of 4-8 MeV, consistent with Solar-Maximum Mission (SSM) Observations. A clear neutron signal was present in the flare of 9 Jun. with the spectrum extending up to 80 MeV and consistent in time with the emission of gamma-rays, confirming the utility of COMPTEL in measuring the solar neutron flux at low energies. The neutron flux below 100 MeV appears to be lower than that of the 3 Jun. 1982 flare by more than an order of magnitude. The neutron signal of the 11 Jun. event is under study. Severe dead time effects resulting from the intense thermal x-rays require significant corrections to the measured flux which increase the magnitude of the associated systematic uncertainties

    Remote sensing applications to resource problems in South Dakota

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    Cooperative projects between RSI and numerous South Dakota agencies have provided a means of incorporating remote sensing techniques into operational programs. Eight projects discussed in detail are: (1) detection of high moisture zones near interstate 90; (2) thermal infrared census of Canada geese in South Dakota; (3) dutch elm disease detection in urban environment; (4) a feasibility study for monitoring effective precipitation in South Dakota using TIROS-N; (5) open and abandoned dump sites in Spink county; (6) the influence of soil reflectance on LANDSAT signatures of crops; (7) A model implementation program for Lake Herman watershed; and (8) the Six-Mile Creek investigation follow-on

    A clinical evaluation of edge induced conjuctival staining with Acuvue and Seequence disposable lenses

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    Disposable extended wear lenses are currently manufactured via two processes. Bausch & Lomb utilizes the conventional spincast method while the Johnson & Johnson lens is produced via a stabilized soft molding process with the lens in a hydrated state. These two processes result in distinctly different lens edge designs. To determine if the differences in lens edge design would result in any signficant conjunctiva! trauma, sixty subjects were fitted with a Johnson & Johnson lens in one eye and a Bausch & Lomb lens in the other eye. After wearing these lenses for a period of 24 hours, evaluation for staining was performed with sodium fluorescein and a Wratten filter. A Wilcoxon test for nonparametric data showed that the Johnson & Johnson lens was responsible for significantly more conjunctiva! staining at an alpha level less than .001

    "I never expected that it would happen, coming to ask me such questions":Ethical aspects of asking children about violence in resource poor settings.

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    BACKGROUND: International epidemiological research into violence against children is increasing in scope and frequency, but little has been written about practical management of the ethical aspects of conducting such research in low and middle-income countries. In this paper, we describe our study procedures and reflect on our experiences conducting a survey of more than 3,700 primary school children in Uganda as part of the Good Schools Study, a cluster randomised controlled trial of a school-based violence prevention intervention. Children were questioned extensively about their experiences of physical, sexual, and emotional violence from a range of different perpetrators. We describe our sensitisation and consent procedures, developed based on our previous research experience and requirements for our study setting. To respond to disclosures of abuse that occurred during our survey, we describe a referral algorithm developed in conjunction with local services. We then describe our experience of actually implementing these procedures in our 2012 survey, based on reflections of the research team. Drawing on 40 qualitative interviews, we describe children's experiences of participating in the survey and of being referred to local child protection services. RESULTS: Although we were able to implement much of our protocol in a straightforward manner, we also encountered major challenges in relation to the response of local services to children's disclosures of violence. The research team had to intervene to ensure that children were provided with appropriate support and that our ethical obligations were met. CONCLUSIONS: In resource poor settings, finding local services that can provide appropriate support for children may be challenging, and researchers need to have concrete plans and back-up plans in place to ensure that obligations can be met. The merits of mandatory reporting of children's disclosures to local services need to be considered on a case by case basis-in some places this has the potential to do harm. Research teams also must agree on what level of ancillary care will be provided, and budget accordingly. Further practical examples of how to address the challenges encountered in this work are needed, in order to build a consensus on best practices. TRIAL REGISTRATION: NCT01678846 (clinicaltrials.gov), August 24, 2012

    Creation of Skyrmions in a Spinor Bose-Einstein Condensate

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    We propose a scheme for the creation of skyrmions (coreless vortices) in a Bose-Einstein condensate with hyperfine spin F=1. In this scheme, four traveling-wave laser beams, with Gaussian or Laguerre-Gaussian transverse profiles, induce Raman transitions with an anomalous dependence on the laser polarization, thereby generating the optical potential required for producing skyrmions.Comment: 5 pages, 2 figures, RevTe
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