737 research outputs found

    Location Determinants of Food Manufacturing Investment: Are Non-metropolitan Counties Competitive?

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    Food manufacturing site selection is determined by infrastructure, agglomeration, product and input markets, labor markets, and fiscal attributes of local communities. This article examines how these factors influence location decisions across the rural-urban continuum in the lower forty-eight states of the U.S. Negative binomial regression and spatial clustering methods are used to forecast new food processor location patterns at the county level, 2000-2004. Remote rural areas are at a comparative disadvantage with respect to attracting food processors, but non-metropolitan counties with economic links to urban core areas may be attractive investment sites for footloose, supply, and demand-oriented food manufacturers.firm location, food manufacturing, negative binomial regression, spatial clustering, Community/Rural/Urban Development, R1, R3,

    In the Shadow of the Accretion Disk: Higher Resolution Imaging of the Central Parsec in NGC 4261

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    The physical conditions in the inner parsec of accretion disks believed to orbit the central black holes in active galactic nuclei can be probed by imaging the absorption (by ionized gas in the disk) of background emission from a radio counterjet. We report high angular resolution VLBI observations of the nearby (about 40 Mpc) radio galaxy NGC 4261 that confirm free-free absorption of radio emission from a counterjet by a geometrically thin, nearly edge-on disk at 1.6, 4.8, and 8.4 GHz. The angular width and depth of the absorption appears to increase with decreasing frequency, as expected. We derive an average electron density of ~10E4 per cc at a disk radius of about 0.2 pc, assuming that the inner disk inclination and opening angles are the same as at larger radii. Pressure balance between the thermal gas and the magnetic field in the disk implies an average field strength of 0.1 milligauss at a radius of 0.2 pc. These are the closest-in free-free absorption measurements to date of the conditions in an extragalactic accretion disk orbiting a black hole with a well-determined mass. If a standard advection-dominated accretion flow exists in the disk center, then the transition between thin and thick disk regions must occur at a radius less than 0.2 pc (4000 Schwarzschild radii).Comment: 20 pages including 12 figures. Accepted for publication in Ap

    The Relevance of Information Sources on Adoption of Precision Farming Technologies by Cotton Producers

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    Replaced with revised version of paper 02/16/11.strategic communication, competitiveness, extension, economics of information, technology diffusion, technology supply, communication methods, knowledge management, Production Economics, Research and Development/Tech Change/Emerging Technologies, Teaching/Communication/Extension/Profession, D22, D80, D82, D83, Q12, Q16,

    Negative Electron Affinity Effect on the Surface of Chemical Vapor Deposited Diamond Polycrystalline Films

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    Strong negative electron affinity effects have been observed on the surface of as-grown chemical vapor deposited diamond using Secondary Electron Emission. The test samples were randomly oriented and the surface was terminated with hydrogen. The effect appears as an intensive peak in the low energy part of the spectrum of the electron energy distribution and may be described in the model of effective negative electron affinity

    Investigation of transition frequencies of two acoustically coupled bubbles using a direct numerical simulation technique

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    The theoretical results regarding the ``transition frequencies'' of two acoustically interacting bubbles have been verified numerically. The theory provided by Ida [Phys. Lett. A 297 (2002) 210] predicted the existence of three transition frequencies per bubble, each of which has the phase difference of π/2\pi /2 between a bubble's pulsation and the external sound field, while previous theories predicted only two natural frequencies which cause such phase shifts. Namely, two of the three transition frequencies correspond to the natural frequencies, while the remaining does not. In a subsequent paper [M. Ida, Phys. Rev. E 67 (2003) 056617], it was shown theoretically that transition frequencies other than the natural frequencies may cause the sign reversal of the secondary Bjerknes force acting between pulsating bubbles. In the present study, we employ a direct numerical simulation technique that uses the compressible Navier-Stokes equations with a surface-tension term as the governing equations to investigate the transition frequencies of two coupled bubbles by observing their pulsation amplitudes and directions of translational motion, both of which change as the driving frequency changes. The numerical results reproduce the recent theoretical predictions, validating the existence of the transition frequencies not corresponding to the natural frequency.Comment: 18 pages, 8 figures, in pres

    Atmospheric pressure plasma analysis by modulated molecular beam mass spectrometry

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    Fractional no. d. measurements for a radiofrequency plasma needle operating at atm. pressure were obtained using a mol. beam mass spectrometer (MBMS) system designed for diagnostics of atm. plasmas. The MBMS system comprises three differentially pumped stages and a mass/energy analyzer and includes an automated beam-to-background measurement facility as a software-controlled chopper mechanism. The automation of the beam modulation allows the neutral components in the plasma to be rapidly and accurately measured using the mass spectrometer by threshold ionization techniques. Data are reported for plasma generated by a needle plasma source operated using a He/air mixt. In particular, data for the conversion of atm. O and N into nitric oxide are discussed with ref. to its significance for medical applications such as disinfecting wounds and dental cavities and for microsurgery. [on SciFinder (R)

    CL100 expression is down-regulated in advanced epithelial ovarian cancer and its re-expression decreases its malignant potential

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    Although early stage ovarian cancer can be effectively treated with surgery and chemotherapy, the majority of cases present with advanced disease, which remains essentially incurable. Unfortunately, little is known about the genes important for the development and progression of this disease. In this study, the expression of 68 phosphatases was determined in immortalized ovarian epithelial cells (IOSE) and compared to ovarian cancer cell lines. CL100, a dual specificity phosphatase, displayed 10-25-fold higher expression in normal compared to malignant ovarian cell lines. Immunohistochemical staining of normal ovaries and 68 ovarian cancer specimens confirmed this differential expression. Re-expression of CL100 in ovarian cancer cells decreased adherent and non-adherent cell growth and induced phenotypic changes including loss of filopodia and lamellipodia with an associated decrease in cell motility. Induced expression of CL100 in ovarian cancer cells suppressed intraperitoneal tumor growth in nude mice. These results show for the first time that CL100 expression is altered in human ovarian cancer, that CL100 expression changes cell morphology and motility, and that it suppresses intraperitoneal growth of human ovarian epithelial cancer. These data suggest that down-regulation of CL100 may play a role in the progression of human ovarian cancer

    Observations on the release of gas-phase potassium during the combustion of single particles of biomass

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    One of the more significant characteristics of solid biomass fuels as compared to coal is the quantity of potassium that they contain. Potassium content influences ash deposition and corrosion mechanisms in furnaces, the effects of which may differ depending on phase transformations of potassium species in the gas phase and condensed phase. The fate of potassium from the fuel during the combustion process is therefore an important concern. To investigate this, an experimental method is presented in which the release patterns from single particles of various biomass fuels are measured by use of flame emission spectroscopy implemented using a custom-built photo-detector device. Single particles of fuel are combusted in a methane flame with a gas temperature of ∼1800 K. The observed potassium release patterns for thirteen solid biomass materials are presented. The data are analyzed to examine the relationships between: the level of potassium in the fuel particle; the fraction of potassium released at each stage of combustion and the peak rate of release of potassium to gas-phase during combustion. Correlations between these quantities are identified with key trends, patterns and differences highlighted. The analyses provide useful information for the development and validation of modelling of potassium release during combustion of biomass
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