234,343 research outputs found

    Extending the automated zoning procedure to reconcile incompatible zoning systems

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    This paper concerns the problem of matching incompatible zonal geographies, for example in the context of comparing census outputs over time. The automated zoning procedure (AZP) proposed by Openshaw (1977) is reviewed and extended to permit its application to the intersection of two zonal systems. A population stress statistic is proposed which may be used in the extended AZP algorithm in order to maximise the match between two zonal geographies. An implementation of this approach is described, and illustrated by reference to UK Census dat

    The GALEX Extended Mission: Surveying UV Tracers of the Hidden Side of Galaxy Evolution

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    The Galaxy Evolution Explorer (GALEX) continues its surveys of the ultraviolet sky. GALEX surveys have supported the following galaxy evolution investigations: calibrating UV as a star formation rate tracer, using wide and deep surveys to measure star formation history, studying the evolution of dust extinction and metallicity, selecting and analyzing galaxies in transitory states, finding local analogs to Lyman Break Galaxies, probing and time-dating star formation in a wide variety of physical regimes. Our continuing mission is focussed on relating star formation history and galaxy evolution paths to the properties of dark matter halos and their assembly history, and on beginning to relate the evolution of galaxies to that of black holes and the intergalactic medium. GALEX has proven that the UV is an ideal band to find and map star formation in low mass, low density objects, and potentially in primordial gas. With future UV missions it may be possible to map emission from the intergalactic and circum-galactic medium, and make a definitive connection between galaxy evolution and the cooling, accretion, heating, and enrichment of gas in the cosmic web

    Effect of the Magellanic Clouds on the Milky Way disk and VICE VERSA

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    The satellite-disk interaction provides limits on halo properties in two ways: (1) physical arguments motivate the excitation of observable Galactic disk structure in the presence of a massive halo, although precise limits on halo parameters are scenario-dependent; (2) conversely, the Milky Way as a whole has significant dynamical effect on LMC structure and this interaction also leads to halo limits. Together, these scenarios give strong corroboration of our current gravitational mass estimates and suggests a rapidly evolving LMC.Comment: 12 pages, 8 Postscript figures, uses paspconf.sty. To appear in the Third Stromlo Symposium: The Galactic Halo (ASP Conference Series), in press. HTML version available at: http://www-astro.phast.umass.edu/~weinberg/stroml

    Kinematic Signature of a Rotating Bar Near a Resonance

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    There have been several recent suggestions that the Milky Way has rotating bar-like features based on HI and star count data. In this paper, I show that such features cause distinctive stellar kinematic signatures near OLR and ILR. The effects of these resonances may be observable far from the peak density of the pattern and relatively nearby the solar position. The details of the kinematic signatures depend on the evolutionary history of the `bar' and therefore velocity data, both systemic and velocity dispersion, may be used to probe the evolutionary history as well as the present state of the Galaxy. Kinematic models for a variety of simple scenarios are presented. Models with evolving pattern speeds show significantly stronger dispersion signatures than those with static pattern speeds, suggesting that useful observational constraints are possible. The models are applied to the proposed rotating spheroid and bar models; we find: 1) none of these models chosen to represent the proposed large-scale rotating spheroid are consistent with the stellar kinematics; and 2) a Galactic bar with semimajor axis of 3\kpc will cause a large increase in velocity dispersion in the vicinity of OLR (\sim5\kpc) with little change in the net radial motion and such a signature is suggested by K-giant velocity data. Potential future observations and analyses are discussed.Comment: 24 pages, AAS LaTeX macros v3.0, 23 figures (available on request

    Encountering and Countering Tribal Conflict With Film and Dialogue

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    Martin explores the ability of group leaders to overcome resistance to reconciliation in group conflicts, whether innate or otherwise. He uses an example of a group conflict that occurred across religious lines with the pending release of a movie titled Theologians Under Hitler. Even if out-group biases make group conflicts harder to resolve, offsetting that complication might be a predisposition to attend to the views of a respected leader of the in-group

    Summary Talk: First Workshop on Forward Physics and Luminosity Determination at the LHC

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    An attempt is made to summarize the discussion at the Workshop, except for the panel discussion on the ability of the LHC detectors to accommodate forward reactions. The Workshop focused on two main topics. The first topic was forward physics at the LHC. Predictions were made for forward reactions, including elastic scattering and soft diffractive processes, intopic was forward physics at the LHC. Predictions were made for forward reactions, including elastic scattering and soft diffractive processes, in terms of (multi) Pomeron exchange, using knowledge gained at lower energies. The survival probability of rapidity gaps accompanying hard subprocesses was studied. The nature of the Pomeron, before and after QCD, was exposed, and some aspects of small x physics at the LHC were considered. The second topic of the Workshop concerned the accuracy of the luminosity measuring processes at the LHC. Attention concentrated on three methods. The classic approach based on the optical theorem, secondly, the observation of the pure QED process of lepton-pair (l^+l^-) production by photon-photon fusion and, finally, the measurement of inclusive W and Z production.Comment: 21 pages,10 figures, LaTeX, Workshop at Helsinki, 31 October - 3 November, 200

    Screening and advising by a venture capitalist with a time constraint

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    This paper proposes an intertemporal model of venture capital investment with screening and advising where the venture capitalist´s time endowment is the scarce input factor. Screening improves the selection of firms receiving finance, advising allows firms to develop a marketable product, both have a variable intensity. In our setup, optimal linear contracts solves the moral hazard problem. Screening however asks for an entrepreneur wage and does not allow for upfront payments which would cause severe adverse selection. Project characteristics have implications for screening and advising intensity and the distribution of profits. Finally, we develop a formal version of the "venture capital cycle" by extending the basic setup to a simple model of venture capital supply and demand

    Status of Structure Functions and Partons

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    We briefly review some of the developments in the study of parton distributions which have occurred since DIS2000, including discussion of uncertainties, shadowing, unintegrated and generalized distributions.Comment: 12 pages including 4 figures, summary of talk at DIS200
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