3,845 research outputs found

    Ellipsoidal-mirror reflectometer accurately measures infrared reflectance of materials

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    Reflectometer accurately measures the reflectance of specimens in the infrared beyond 2.5 microns and under geometric conditions approximating normal irradiation and hemispherical viewing. It includes an ellipsoidal mirror, a specially coated averaging sphere associated with a detector for minimizing spatial and angular sensitivity, and an incident flux chopper

    A new ordered compactification

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    A new Wallman-type ordered compactification γ∘X is constructed using maximal CZ-filters (which have filter bases obtained from increasing and decreasing zero sets) as the underlying set. A necessary and sufficient condition is given for γ∘X to coincide with the Nachbin compactification β∘X; in particular γ∘X=β∘X whenever X has the discrete order. The Wallman ordered compactification ω∘X equals γ∘X whenever X is a subspace of Rn. It is shown that γ∘X is always T1, but can fail to be T1-ordered or T2

    Distinguishing cancerous from non-cancerous cells through analysis of electrical noise

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    Since 1984, electric cell-substrate impedance sensing (ECIS) has been used to monitor cell behavior in tissue culture and has proven sensitive to cell morphological changes and cell motility. We have taken ECIS measurements on several cultures of non-cancerous (HOSE) and cancerous (SKOV) human ovarian surface epithelial cells. By analyzing the noise in real and imaginary electrical impedance, we demonstrate that it is possible to distinguish the two cell types purely from signatures of their electrical noise. Our measures include power-spectral exponents, Hurst and detrended fluctuation analysis, and estimates of correlation time; principal-component analysis combines all the measures. The noise from both cancerous and non-cancerous cultures shows correlations on many time scales, but these correlations are stronger for the non-cancerous cells.Comment: 8 pages, 4 figures; submitted to PR

    'White knuckle care work' : violence, gender and new public management in the voluntary sector

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    Drawing on comparative data from Canada and Scotland, this article explores reasons why violence is tolerated in non-profit care settings. This article will provide insights into how workers' orientations to work, the desire to care and the intrinsic rewards from working in a non-profit context interact with the organization of work and managerially constructed workplace norms and cultures (Burawoy, 1979) to offset the tensions in an environment characterized by scarce resources and poor working conditions. This article will also outline how the same environment of scarce resources causes strains in management's efforts to establish such cultures. Working with highly excluded service users with problems that do not respond to easy interventions, workers find themselves working at the edge of their endurance, hanging on by their fingernails, and beginning to participate in various forms of resistance; suggesting that even among the most highly committed, 'white knuckle care' may be unsustainable

    The Importance of Family to Youth Living in Violent Communities

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    The purpose of this study was to investigate family functioning in the relationship between community violence exposure and 1) self-esteem and 2) confrontational coping in a sample of urban youth. Adhering to the tenets of community based participatory research, academic and community partners collaborated on a cross-sectional study with 110 community dwelling urban youth, ages 10–16 living in a city located in the Northeastern United States. As part of a larger survey, this analysis included selected items on lifetime community violence exposure, family functioning, self-esteem and use of confrontational coping strategies in response to community violence. Over 90% of the youth reported some type of lifetime community violence exposure. Controlling for age and gender, older youth and those with healthier family functioning had higher self-esteem; community violence exposure was not associated with self-esteem. Healthier family functioning was associated with decreased use of confrontational coping, though increasing amounts of community violence exposure was still associated with increased confrontational coping. Family can be protective in violent environments. Results from this study directly informed an intervention aimed at youth violence prevention. This study highlights how psychiatric and mental health nurses may be able to address the complex interplay of factors for youth living in violent environments

    An attempt to observe economy globalization: the cross correlation distance evolution of the top 19 GDP's

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    Economy correlations between the 19 richest countries are investigated through their Gross Domestic Product increments. A distance is defined between increment correlation matrix elements and their evolution studied as a function of time and time window size. Unidirectional and Bidirectional Minimal Length Paths are generated and analyzed for different time windows. A sort of critical correlation time window is found indicating a transition for best observations. The mean length path decreases with time, indicating stronger correlations. A new method for estimating a realistic minimal time window to observe correlations and deduce macroeconomy conclusions from such features is thus suggested.Comment: to be published in the Dyses05 proceedings, in Int. J. Mod Phys C 15 pages, 5 figures, 1 tabl

    Random Planar Lattices and Integrated SuperBrownian Excursion

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    In this paper, a surprising connection is described between a specific brand of random lattices, namely planar quadrangulations, and Aldous' Integrated SuperBrownian Excursion (ISE). As a consequence, the radius r_n of a random quadrangulation with n faces is shown to converge, up to scaling, to the width r=R-L of the support of the one-dimensional ISE. More generally the distribution of distances to a random vertex in a random quadrangulation is described in its scaled limit by the random measure ISE shifted to set the minimum of its support in zero. The first combinatorial ingredient is an encoding of quadrangulations by trees embedded in the positive half-line, reminiscent of Cori and Vauquelin's well labelled trees. The second step relates these trees to embedded (discrete) trees in the sense of Aldous, via the conjugation of tree principle, an analogue for trees of Vervaat's construction of the Brownian excursion from the bridge. From probability theory, we need a new result of independent interest: the weak convergence of the encoding of a random embedded plane tree by two contour walks to the Brownian snake description of ISE. Our results suggest the existence of a Continuum Random Map describing in term of ISE the scaled limit of the dynamical triangulations considered in two-dimensional pure quantum gravity.Comment: 44 pages, 22 figures. Slides and extended abstract version are available at http://www.loria.fr/~schaeffe/Pub/Diameter/ and http://www.iecn.u-nancy.fr/~chassain
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