11,769 research outputs found

    The Manchester occulting mask imager (MOMI) - first results on the environment of P Cygni

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    The design and first use of the Manchester occulting mask imager (MOMI) is described. This device, when combined with the Cassegrain or Ritchey-Chretien foci of large telescopes, is dedicated to the imagery of faint line emission regions around bright central sources. Initial observations, with MOMI on the Nordic Optical telescope (NOT), of the V=4.8 mag P~Cygni environment, have revealed a \geq~5~arcmin long [NII] 6584A emitting filament projecting from the outer nebular shell of this luminous blue variable (LBV) star. The presence of a mono-polar lobe older than both the inner (22 arcsec diameter) and outer (1.6 arcmin diameter) shells is suggested.Comment: 4 pages, 4 figures, accepted MNRAS 1998 June 1

    London or New York: where and when does the gold price originate?

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    We investigate the Information Shares (ISs) of the two main centres of gold trading, over a 25-year period, using nonoverlapping 4-month windows. We find that neither London nor New York is dominant in terms of price IS, that the dominant market switches from time to time and that these switches do not appear to be very clearly linkable to macroeconomic or political events

    Critical Temperature and Amplitude Ratios from a Finite-Temperature Renormalization Group

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    We study \l\f^4 theory using an environmentally friendly finite-temperature renormalization group. We derive flow equations, using a fiducial temperature as flow parameter, develop them perturbatively in an expansion free from ultraviolet and infrared divergences, then integrate them numerically from zero to temperatures above the critical temperature. The critical temperature, at which the mass vanishes, is obtained by integrating the flow equations and is determined as a function of the zero-temperature mass and coupling. We calculate the field expectation value and minimum of the effective potential as functions of temperature and derive some universal amplitude ratios which connect the broken and symmetric phases of the theory. The latter are found to be in good agreement with those of the three-dimensional Ising model obtained from high- and low-temperature series expansions.Comment: 14 pages of LaTeX. Postscript figures available upon request form [email protected]

    Where are the veterinarian shortage areas anyway?

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    This paper describes an econometric model to evaluate factors associated with a county’s likelihood of being designated as a private practice shortage area under the United States' Veterinary Medicine Loan Repayment Program (VMLRP). Study determinants of equilibrium food animal veterinarian location choices were also evaluated and used as a benchmark to assess the shortage designation process. On the whole the program appears to perform quite well. For several states, however, VMLRP shortage designations are inconsistent with the model of food animal veterinarian shortages. Comparative shortage is generally more severe in states that have no VMLRP designated private practice shortage counties than in states that do.economic externalities, food animal veterinarians, loan repayment program, Agricultural and Food Policy, Livestock Production/Industries,

    The Specific Heat of a Ferromagnetic Film.

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    We analyze the specific heat for the O(N)O(N) vector model on a dd-dimensional film geometry of thickness LL using ``environmentally friendly'' renormalization. We consider periodic, Dirichlet and antiperiodic boundary conditions, deriving expressions for the specific heat and an effective specific heat exponent, \alpha\ef. In the case of d=3d=3, for N=1N=1, by matching to the exact exponent of the two dimensional Ising model we capture the crossover for \xi_L\ra\infty between power law behaviour in the limit {L\over\xi_L}\ra\infty and logarithmic behaviour in the limit {L\over\xi_L}\ra0 for fixed LL, where ξL\xi_L is the correlation length in the transverse dimensions.Comment: 21 pages of Plain TeX. Postscript figures available upon request from [email protected]

    Transfer Learning for Multi-language Twitter Election Classification

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    Both politicians and citizens are increasingly embracing social media as a means to disseminate information and comment on various topics, particularly during significant political events, such as elections. Such commentary during elections is also of interest to social scientists and pollsters. To facilitate the study of social media during elections, there is a need to automatically identify posts that are topically related to those elections. However, current studies have focused on elections within English-speaking regions, and hence the resultant election content classifiers are only applicable for elections in countries where the predominant language is English. On the other hand, as social media is becoming more prevalent worldwide, there is an increasing need for election classifiers that can be generalised across different languages, without building a training dataset for each election. In this paper, based upon transfer learning, we study the development of effective and reusable election classifiers for use on social media across multiple languages. We combine transfer learning with different classifiers such as Support Vector Machines (SVM) and state-of-the-art Convolutional Neural Networks (CNN), which make use of word embedding representations for each social media post. We generalise the learned classifier models for cross-language classification by using a linear translation approach to map the word embedding vectors from one language into another. Experiments conducted over two election datasets in different languages show that without using any training data from the target language, linear translations outperform a classical transfer learning approach, namely Transfer Component Analysis (TCA), by 80% in recall and 25% in F1 measure

    Explanation and Elaboration Document for the STROBE-Vet Statement: Strengthening the Reporting of Observational Studies in Epidemiology—Veterinary Extension

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    The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement was first published in 2007 and again in 2014. The purpose of the original STROBE was to provide guidance for authors, reviewers and editors to improve the comprehensiveness of reporting; however, STROBE has a unique focus on observational studies. Although much of the guidance provided by the original STROBE document is directly applicable, it was deemed useful to map those statements to veterinary concepts, provide veterinary examples and highlight unique aspects of reporting in veterinary observational studies. Here, we present the examples and explanations for the checklist items included in the STROBE-Vet Statement. Thus, this is a companion document to the STROBE-Vet Statement Methods and process document, which describes the checklist and how it was developed

    Dimensional Crossover in the Large N Limit

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    We consider dimensional crossover for an O(N)O(N) Landau-Ginzburg-Wilson model on a dd-dimensional film geometry of thickness LL in the large NN-limit. We calculate the full universal crossover scaling forms for the free energy and the equation of state. We compare the results obtained using ``environmentally friendly'' renormalization with those found using a direct, non-renormalization group approach. A set of effective critical exponents are calculated and scaling laws for these exponents are shown to hold exactly, thereby yielding non-trivial relations between the various thermodynamic scaling functions.Comment: 25 pages of PlainTe

    Comparison of Subjective Responses to Oral and Intravenous Alcohol Administration under Similar Systemic Exposures

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    Objective To test whether an individual's subjective responses to alcohol are similar when the breath alcohol concentration (BrAC) trajectory resulting from oral administration is matched by intravenous administration. Background Individuals perceive the effects of alcohol differently, and the variation is commonly used in research assessing the risk for developing an alcohol use disorder. Such research is supported by both oral and intravenous alcohol administration techniques, and any differences attributable to the route employed should be understood. Methods We conducted a 2‐session, within‐subject study in 44 young adult, healthy, non‐dependent drinkers (22 females and 22 males). In the first session, subjects ingested a dose of alcohol which was individually calculated, on the basis of total body water, to yield a peak BrAC near 80 mg/dl, and the resulting BrAC trajectory was recorded. A few days later, subjects received an intravenous alcohol infusion rate profile, pre‐computed to replicate each individual's oral alcohol BrAC trajectory. In both sessions, we assessed 4 subjective responses to alcohol: SEDATION, SIMULATION, INTOXICATION, and HIGH; at baseline and frequently for 4 hours. We compared the individuals’ baseline‐corrected responses at peak BrAC and at half‐peak BrAC on both the ascending and descending limbs. We also computed and compared Pearson‐product moment correlations of responses by route of administration, the Mellanby measure of acute adaptation to alcohol, and the area under the entire response curve for each subjective response. Results No significant differences in any measure could be attributed to the route of alcohol administration. Eleven of 12 response comparisons were significantly correlated across the routes of alcohol administration, with 9 surviving correction for multiple measures, as did the Mellanby effect and area under the response curve correlations. Conclusion The route of alcohol administration has a minimal effect on subjective responses to alcohol when an individual's BrAC exposure profiles are similar

    Modular Invariance of Finite Size Corrections and a Vortex Critical Phase

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    We analyze a continuous spin Gaussian model on a toroidal triangular lattice with periods L0L_0 and L1L_1 where the spins carry a representation of the fundamental group of the torus labeled by phases u0u_0 and u1u_1. We find the {\it exact finite size and lattice corrections}, to the partition function ZZ, for arbitrary mass mm and phases uiu_i. Summing Z1/2Z^{-1/2} over phases gives the corresponding result for the Ising model. The limits m0m\rightarrow0 and ui0u_i\rightarrow0 do not commute. With m=0m=0 the model exhibits a {\it vortex critical phase} when at least one of the uiu_i is non-zero. In the continuum or scaling limit, for arbitrary mm, the finite size corrections to lnZ-\ln Z are {\it modular invariant} and for the critical phase are given by elliptic theta functions. In the cylinder limit L1L_1\rightarrow\infty the ``cylinder charge'' c(u0,m2L02)c(u_0,m^2L_0^2) is a non-monotonic function of mm that ranges from 2(1+6u0(u01))2(1+6u_0(u_0-1)) for m=0m=0 to zero for mm\rightarrow\infty.Comment: 12 pages of Plain TeX with two postscript figure insertions called torusfg1.ps and torusfg2.ps which can be obtained upon request from [email protected]
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