3,656 research outputs found

    Legal Nationalism:Lord Cooper, Legal History and Comparative Law

    Get PDF
    Considers the linkages between Lord Cooper's analysis of Scottish legal history and his view of the importance of comparative law for modern Scots law development

    Statistical Evidence for Three classes of Gamma-ray Bursts

    Full text link
    Two different multivariate clustering techniques, the K-means partitioning method and the Dirichlet process of mixture modeling, have been applied to the BATSE Gamma-ray burst (GRB) catalog, to obtain the optimum number of coherent groups. In the standard paradigm, GRB are classified in only two groups, the long and short bursts. However, for both the clustering techniques, the optimal number of classes was found to be three, a result which is consistent with previous statistical analysis. In this classification, the long bursts are further divided into two groups which are primarily differentiated by their total fluence and duration and hence are named low and high fluence GRB. Analysis of GRB with known red-shifts and spectral parameters suggests that low fluence GRB have nearly constant isotropic energy output of 10^{52} ergs while for the high fluence ones, the energy output ranges from 10^{52} to 10^{54} ergs. It is speculated that the three kinds of GRBs reflect three different origins: mergers of neutron star systems, mergers between white dwarfs and neutron stars, and collapse of massive stars.Comment: 7 pages, accepted for publication in the Astrophysical Journal. Minor editorial change

    Significance analysis and statistical mechanics: an application to clustering

    Full text link
    This paper addresses the statistical significance of structures in random data: Given a set of vectors and a measure of mutual similarity, how likely does a subset of these vectors form a cluster with enhanced similarity among its elements? The computation of this cluster p-value for randomly distributed vectors is mapped onto a well-defined problem of statistical mechanics. We solve this problem analytically, establishing a connection between the physics of quenched disorder and multiple testing statistics in clustering and related problems. In an application to gene expression data, we find a remarkable link between the statistical significance of a cluster and the functional relationships between its genes.Comment: to appear in Phys. Rev. Let

    Soccer Player With Sun Allergy

    Get PDF
    Please view the clinical abstract in the attached PDF fil

    Elemental Abundances of Solar Sibling Candidates

    Get PDF
    Dynamical information along with survey data on metallicity and in some cases age have been used recently by some authors to search for candidates of stars that were born in the cluster where the Sun formed. We have acquired high resolution, high signal-to-noise ratio spectra for 30 of these objects to determine, using detailed elemental abundance analysis, if they could be true solar siblings. Only two of the candidates are found to have solar chemical composition. Updated modeling of the stars' past orbits in a realistic Galactic potential reveals that one of them, HD162826, satisfies both chemical and dynamical conditions for being a sibling of the Sun. Measurements of rare-element abundances for this star further confirm its solar composition, with the only possible exception of Sm. Analysis of long-term high-precision radial velocity data rules out the presence of hot Jupiters and confirms that this star is not in a binary system. We find that chemical tagging does not necessarily benefit from studying as many elements as possible, but instead from identifying and carefully measuring the abundances of those elements which show large star-to-star scatter at a given metallicity. Future searches employing data products from ongoing massive astrometric and spectroscopic surveys can be optimized by acknowledging this fact.Comment: ApJ, in press. Tables 2 and 4 are available in full in the "Other formats: source" downloa

    Revisiting rho 1 Cancri e: A New Mass Determination Of The Transiting super-Earth

    Get PDF
    We present a mass determination for the transiting super-Earth rho 1 Cancri e based on nearly 700 precise radial velocity (RV) measurements. This extensive RV data set consists of data collected by the McDonald Observatory planet search and published data from Lick and Keck observatories (Fischer et al. 2008). We obtained 212 RV measurements with the Tull Coude Spectrograph at the Harlan J. Smith 2.7 m Telescope and combined them with a new Doppler reduction of the 131 spectra that we have taken in 2003-2004 with the High-Resolution-Spectrograph (HRS) at the Hobby-Eberly Telescope (HET) for the original discovery of rho 1 Cancri e. Using this large data set we obtain a 5-planet Keplerian orbital solution for the system and measure an RV semi-amplitude of K = 6.29 +/- 0.21 m/s for rho 1 Cnc e and determine a mass of 8.37 +/- 0.38 M_Earth. The uncertainty in mass is thus less than 5%. This planet was previously found to transit its parent star (Winn et al. 2011, Demory et al. 2011), which allowed them to estimate its radius. Combined with the latest radius estimate from Gillon et al. (2012), we obtain a mean density of rho = 4.50 +/- 0.20 g/cm^3. The location of rho 1 Cnc e in the mass-radius diagram suggests that the planet contains a significant amount of volitales, possibly a water-rich envelope surrounding a rocky core.Comment: 16 pages, 5 figures, accepted for publication in the Astrophysical Journal (the 300+ RV measurements will be published as online tables or can be obtained from the author

    Essais d'introduction de quatre espèces de bousiers Scarabaeinae en Nouvelle Calédonie et au Vanuatu

    Get PDF
    La Nouvelle Calédonie et le Vanuatu étaient initialement dépourvus de gros mammifères et leur entomofaune ne comportait pas de bousiers susceptibles de fractionner et d'enfouir les déjections des ruminants importés par l'homme. En prolongement d'une vaste opération d'introduction de bousiers effectuée en Australie par le CSIRO, on a essayé d'implanter dans ces deux archipels quatre espèces de #Scarabaeinae appartenant aux tribus des Onthophagini (#Onthophagus gazella), des Oniticellini (#Euoniticellus intermedius et #Liatongus militaris) et des Sisyphini (#Sisyphus spinipes). Cinq ans après ces tentatives, on peut estimer que trois espèces se sont établies dans chacun de ces ensembles d'îles : #O. gazella, #E. intermedius et #S. spinipes en Nouvelle Calédonie; #O. gazella, #E. intermedius et #L. militaris au Vanuatu. Les enquêtes effectuées ont également permis de récolter deux espèces probablement introduites antérieurement : #Onthophagus consentaneus en Nouvelle Calédonie et #Copris incertus$ au Vanuatu. (Résumé d'auteur
    corecore