3,254 research outputs found

    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

    The Amateur Sky Survey Mark III Project

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    The Amateur Sky Survey (TASS) is a loose confederation of amateur and professional astronomers. We describe the design and construction of our Mark III system, a set of wide-field drift-scan CCD cameras which monitor the celestial equator down to thirteenth magnitude in several passbands. We explain the methods by which images are gathered, processed, and reduced into lists of stellar positions and magnitudes. Over the period October, 1996, to November, 1998, we compiled a large database of photometric measurements. One of our results is the "tenxcat" catalog, which contains measurements on the standard Johnson-Cousins system for 367,241 stars; it contains links to the light curves of these stars as well.Comment: 20 pages, including 4 figures; additional JPEG files for Figures 1, 2. Submitted to PAS

    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

    Decomposition of the Inequality of Income distribution by income types- Application for Romania

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    This paper identifies the salient factors that characterize the inequality income distribution for Romania. Data analysis is rigorously carried out using sophisticated techniques borrowed from classical statistics (Theil). Decomposition of the inequalities measured by the Theil index is also performed. This study relies on an exhaustive (11.1 million records for 2014) data-set for total personal gross income of Romanian citizens

    Spin Wave Instability of Itinerant Ferromagnet

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    We show variationally that instability of the ferromagnetic state in the Hubbard model is largely controlled by softening of a long-wavelength spin-wave excitation, except in the over-doped strong-coupling region where the individual-particle excitation becomes unstable first. A similar conclusion is drawn also for the double exchange ferromagnet. Generally the spin-wave instability may be regarded as a precursor of the metal-insulator transition.Comment: 11 pages, 8 figure

    Bada Bang, Bada Boom: Dispersal of fall migrating cormorants to protect sportfish on Oneida Lake, New York

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    The interior population of double-crested cormorants (Phalacrocorax auritus) continues to increase. As a result, conflicts between human interests and cormorants have intensified. The impacts of nesting, roosting, and migrating cormorants include predation at aquaculture facilities, interspecific competition with rare species including common terns {Sterna hirundo), and impacts to private property. In addition, heightened public and scientific debate regarding cormorant impacts on sportfish has accelerated the need for effective, socially acceptable methods for managing local conflicts. In 1998 and 1999, USDA, APHIS, Wildlife Services; the New York State Department of Environmental Conservation; and USGS, New York Fish and Wildlife Research Cooperative collaborated on a pilot project to investigate prospective methods and strategies for reducing predation of yellow perch (Perca flavescens) and walleye (Stizostedion vitreum) by fall migrating cormorants on Oneida Lake, New York. The goal of the cooperative program was to reduce stopover time, thereby reducing predation on fish stocks by migrating cormorants. A lakewide integrated non-lethal harassment and roost management program was initiated to disperse local and migrating cormorants from September to October each year. A variety of methods were used to manage cormorants including: electronic guards, propane cannons, mylar tape, human effigies, pyrotechnics, and dispersing birds with a boat. Harassment was focused on birds loafing on the water as well as day and night roosting sites (8 day and 2 night roosts). A total of 52,840 cormorants was dispersed (in many cases individual birds were harassed multiple times) using 1,518 pyrotechnics and 649 staff hours on the lake during the 2 years of the program. Surveys documented a 61%-98% reduction of the cormorants population on Oneida Lake compared to mean counts during the same time period from 1995-1997. Estimated total annual fish consumption by cormorants was reduced by 30% in 1998. Some off-site impacts of the program were seen with increased flocks of cormorants documented on nearby lakes

    Constrained by managerialism : caring as participation in the voluntary social services

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    The data in this study show that care is a connective process, underlying and motivating participation and as a force that compels involvement in the lives of others, care is at least a micro-participative process. Care or affinity not only persisted in the face of opposition, but it was also used by workers as a counter discourse and set of practices with which to resist the erosion of worker participation and open up less autonomized practices and ways of connecting with fellow staff, clients and the communities they served. The data suggest that while managerialism and taylorised practice models may remove or reduce opportunities for worker participation, care is a theme or storyline that gave workers other ways to understand their work and why they did it, as well as ways they were prepared to resist managerial priorities and directives, including the erosion of various kinds of direct and indirect participation. The degree of resistance possible, even in the highly technocratic worksite in Australia, shows that cracks and fissures exist within managerialism

    Three routes to the exact asymptotics for the one-dimensional quantum walk

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    We demonstrate an alternative method for calculating the asymptotic behaviour of the discrete one-coin quantum walk on the infinite line, via the Jacobi polynomials that arise in the path integral representation. This is significantly easier to use than the Darboux method. It also provides a single integral representation for the wavefunction that works over the full range of positions, n,n, including throughout the transitional range where the behaviour changes from oscillatory to exponential. Previous analyses of this system have run into difficulties in the transitional range, because the approximations on which they were based break down here. The fact that there are two different kinds of approach to this problem (Path Integral vs. Schr\"{o}dinger wave mechanics) is ultimately a manifestation of the equivalence between the path-integral formulation of quantum mechanics and the original formulation developed in the 1920s. We discuss how and why our approach is related to the two methods that have already been used to analyse these systems.Comment: 25 pages, AMS preprint format, 4 figures as encapsulated postscript. Replaced because there were sign errors in equations (80) & (85) and Lemma 2 of the journal version (v3

    Three-body correlations in the Nagaoka state on the square lattice

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    A three-body scattering theory previously proposed by one of the present authors is developed to be applied to the saturated ferromagnetic state in the two-dimensional Hubbard model. The single-particle Green's function is calculated by taking account of the multiple scattering between two electrons and one hole. Several limiting cases are discussed and the relation to the variational principle is examined. The importance of the three-body correlation is demonstrated in comparison with the results of the ladder approximation. A possible phase boundary for the Nagaoka ground state is presented for the square lattice, which improves the previous variational results.Comment: 13 pages, 8 Postscript figures, submitted to Phys.Rev.
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