903 research outputs found

    A water policy-land use computer simulation model

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    This paper describes the philosophy, algorithms, and implementation of a computer-oriented land use forecasting-water policy simulation model. The model is applicable to SMSA's organized on a census tract basis by counties. The forecasts are macro to the census tract level for industrial, residential, commercial and public land uses, and are dynamically altered by hypothesized water management policies. Modeling is based on an economic data base of the region, and is extremely flexible for the user. An example set of simulations is included for illustratlve purposes.Project # B-088-MO Agreement # 14-31-0001-390

    Harmonic Vibrational Excitations in Disordered Solids and the "Boson Peak"

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    We consider a system of coupled classical harmonic oscillators with spatially fluctuating nearest-neighbor force constants on a simple cubic lattice. The model is solved both by numerically diagonalizing the Hamiltonian and by applying the single-bond coherent potential approximation. The results for the density of states g(ω)g(\omega) are in excellent agreement with each other. As the degree of disorder is increased the system becomes unstable due to the presence of negative force constants. If the system is near the borderline of stability a low-frequency peak appears in the reduced density of states g(ω)/ω2g(\omega)/\omega^2 as a precursor of the instability. We argue that this peak is the analogon of the "boson peak", observed in structural glasses. By means of the level distance statistics we show that the peak is not associated with localized states

    A search for new particles in proton‐nucleus collisions at 400 GeV/c

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    We report preliminary results from a search for new particles produced in proton‐nucleus collisions at 400 GeV/c. A double‐arm spectrometer is used to detect two‐body final states where each spectrometer arm has the capability of uniquely identifying Π±, K±, p, ?, Ό±, and ϕ. The Jψ is measured in the ÎŒ+Ό− mode.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87398/2/30_1.pd

    Observations of TeV photons at the Whipple Observatory

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    The Whipple Observatory 10 m gamma‐ray telescope has been used to search for TeV gamma‐ray emission from a number of objects. This paper reports observations of six galactic and three extragalactic objects using the Cherenkov image technique. With the introduction of a high‐resolution camera (1/4° pixel) in 1988, the Crab Nebula was detected at a significance level of 20 σ in 30 hours of on‐source observation. Upper limits at a fraction of the Crab flux are set for most of the other objects, based on the absence of any significant dc excess or periodic effect when an a priori Monte Carlo determined imaging selection criterion (the ‘‘azwidth cut’’) is employed. There are weak indications that one source, Hercules X‐1, may be an episodic emitter. The Whipple detection system will be improved shortly with the addition of a second reflector 11 m in diameter (GRANITE) for stereoscopic viewing of showers. The combination of the two‐reflector system should have a signal‐to‐noise advantage of 103 over a simple nonimaging Cherenkov receiver.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87437/2/47_1.pd

    Governmental Context Determines Institutional Value: Independently Certified Performance and Failure in the Spanish Newspaper Industry

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    Many societies demand that independent professionals (e.g. auditors) certify the performance of firms. The value placed on such certification (i.e. the public perception of reliability/unreliability that may impact on an organization's success/failure) is not uniform, however, but contingent upon changing political contexts. This study presents and analyses data on the entire population of newspapers in Spain from 1966 to 1993, a time of peaceful transition from military dictatorship to capitalist democracy. Our results highlight the contingent nature of institutional life, demonstrating how changes in political contexts are associated with varying understandings of institutions. In particular, our findings support the prediction that, under a dictatorship, independently certified performance is not instrumental in organizational success or failure whereas, in a modern democracy, the certification process has a positive effect on the survival chances of firms.Publicad

    Design and Creative Methods as a Practice of Liminality in Community-Academic Research Projects

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    This paper aims to explore the types of spaces and experiences that are created by design and creative practices. More specifically, it focuses on how design and creative practices can engender transformations in the mindset, knowledge, emotions and social relations of people who participate in such practices. To do this, the paper investigates the concepts of liminality and liminal spaces, and the relationships between design/creative methods and liminal spaces using insights from four case studies. The results reveal that design and creative practices may create liminal spaces in many ways, such as neutralizing the working environments, encouraging people to experiment with new ideas and helping them express themselves more freely

    TEV gamma ray emission from the active galactic nucleus Markarian 421

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    TeV energy gamma ray emission from the blazar Markarian 421 was detected with the Whipple 10 meter imaging Cherenkov telescope initially during the observation period March‐June 1992 at an average photon flux of 1.5×10−11 cm2 s−1. The photon spectrum in the TeV range lies on the extrapolation of the data points observed by EGRET during viewing phase I and indicates that the emission follows an unchanged power law between 100 MeV and 10 TeV with no significant intergalactic absorption. More recent observations from the spring of 1993 confirm the 1992 measurements. Here we give an update on the status of the observations, the analysis for time variability, and the results from the analysis to determine the spectral index for Markarian 421 at TeV energies.The search for TeV emission from other extragalactic sources detected by the EGRET instrument on the Compton Gamma Ray Observatory at GeV energies have so far been negative.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87648/2/597_1.pd