632 research outputs found

    Sound the Alarm: Limitations of Liability in Alarm Service Contracts

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    Home and business owners increasingly rely on alarm systems to protect against theft and property damage. When a burglary or fire occurs and an alarm service customer discovers that the alarm company negligently failed to call the police or fire department, the customer understandably would expect redress for the company’s failure to provide its service. Many customers would be surprised, though, to discover that an alarm company’s liability is often contractually limited to a relatively token amount unrelated to the cost of the service, even when the alarm company is negligent. Some states view these limitations of liability as exculpatory clauses and determine their enforceability based on whether they are unconscionable or violate public policy. Other states view them as liquidated damages and apply a penalty test to determine their enforceability. This Note addresses the differences between these two approaches in the context of the unique remedy difficulties inherent in alarm service contracts. This Note then argues that the prevailing policy rationales for enforcing alarm service provisions that limit a party’s liability for its own negligence are misguided and advocates that these provisions should not be enforced as a matter of public policy

    Spectroscopic Confirmation of the Dwarf Galaxies Hydra II and Pisces II and the Globular Cluster Laevens 1

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    We present Keck/DEIMOS spectroscopy of stars in the recently discovered Milky Way satellites Hydra II, Pisces II, and Laevens 1. We measured a velocity dispersion of 5.4 (+3.6 -2.4) km/s for Pisces II, but we did not resolve the velocity dispersions of Hydra II or Laevens 1. We marginally resolved the metallicity dispersions of Hydra II and Pisces II but not Laevens 1. Furthermore, Hydra II and Pisces II obey the luminosity-metallicity relation for Milky Way dwarf galaxies ( = -2.02 +/- 0.08 and -2.45 +/- 0.07, respectively), whereas Laevens 1 does not ( = -1.68 +/- 0.05). The kinematic and chemical properties suggest that Hydra II and Pisces II are dwarf galaxies, and Laevens 1 is a globular cluster. We determined that two of the previously observed blue stars near the center of Laevens 1 are not members of the cluster. A third blue star has ambiguous membership. Hydra II has a radial velocity = 303.1 +/- 1.4 km/s, similar to the leading arm of the Magellanic stream. The mass-to-light ratio for Pisces II is 370 (+310 -240) M_sun/L_sun. It is not among the most dark matter-dominated dwarf galaxies, but it is still worthy of inclusion in the search for gamma rays from dark matter self-annihilation.Comment: Accepted to ApJ. v2 has been revised in response to the referee's repor

    Triangulum II: Not Especially Dense After All

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    Among the Milky Way satellites discovered in the past three years, Triangulum II has presented the most difficulty in revealing its dynamical status. Kirby et al. (2015a) identified it as the most dark matter-dominated galaxy known, with a mass-to-light ratio within the half-light radius of 3600 +3500 -2100 M_sun/L_sun. On the other hand, Martin et al. (2016) measured an outer velocity dispersion that is 3.5 +/- 2.1 times larger than the central velocity dispersion, suggesting that the system might not be in equilibrium. From new multi-epoch Keck/DEIMOS measurements of 13 member stars in Triangulum II, we constrain the velocity dispersion to be sigma_v < 3.4 km/s (90% C.L.). Our previous measurement of sigma_v, based on six stars, was inflated by the presence of a binary star with variable radial velocity. We find no evidence that the velocity dispersion increases with radius. The stars display a wide range of metallicities, indicating that Triangulum II retained supernova ejecta and therefore possesses or once possessed a massive dark matter halo. However, the detection of a metallicity dispersion hinges on the membership of the two most metal-rich stars. The stellar mass is lower than galaxies of similar mean stellar metallicity, which might indicate that Triangulum II is either a star cluster or a tidally stripped dwarf galaxy. Detailed abundances of one star show heavily depressed neutron-capture abundances, similar to stars in most other ultra-faint dwarf galaxies but unlike stars in globular clusters.Comment: accepted to ApJ, Table 5 available as a machine-readable table by clicking on "Other formats" on the right. Proof corrections reflected in version

    NGC 2419 -- Another Remnant of Accretion by the Milky Way

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    We isolate a sample of 43 upper RGB stars in the extreme outer halo Galactic globular cluster NGC 2419 from two Keck/DEIMOS slitmasks. The probability that there is more than one contaminating halo field star in this sample is extremely low. Analysis of moderate resolution spectra of these cluster members, as well as of our Keck/HIRES high resolution spectra of a subsample of them, demonstrates that there is a small but real spread in Ca abundance of ~ 0.2 dex within this massive metal-poor globular cluster. This provides additional support to earlier suggestions that NGC 2419 is the remnant of a dwarf galaxy accreted long ago by the Milky Way.Comment: Accepted to the Astrophysical Journa

    Triangulum II: Possibly a Very Dense Ultra-faint Dwarf Galaxy

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    Laevens et al. recently discovered Triangulum II (Tri II), a satellite of the Milky Way. Its Galactocentric distance is 36 kpc, and its luminosity is only 450 L_⊙. Using Keck/DEIMOS, we measured the radial velocities of six member stars within 1'.2 of the center of Tri II, and we found a velocity dispersion of σ_v = 5.1_(-1.4)^(+4.0) km s^(-1). We also measured the metallicities of three stars and found a range of 0.8 dex in [Fe/H]. The velocity and metallicity dispersions identify Tri II as a dark matter-dominated galaxy. The galaxy is moving very quickly toward the Galactic center v_(GSR) = -262 km s^(-1). Although it might be in the process of being tidally disrupted as it approaches pericenter, there is no strong evidence for disruption in our data set. The ellipticity is low, and the mean velocity, 〈|v_(helio)〉 =-382.1 ± 2.9 km s^(-1), rules out an association with the Triangulum–Andromeda substructure or the Pan-Andromeda Archaeological Survey stellar stream. If Tri II is in dynamical equilibrium, then it would have a mass-to-light ratio of 3600_(-2100)^(+3500) M}_⊙ L_⊙^(-1), the highest of any non-disrupting galaxy (those for which dynamical mass estimates are reliable). The density within the 3D half-light radius would be 4.8_(-3.5)^(+8.1) M⊙ pc^(-3), even higher than Segue 1. Hence, Tri II is an excellent candidate for the indirect detection of dark matter annihilation

    Dynamically Warped Theory Space and Collective Supersymmetry Breaking

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    We study deconstructed gauge theories in which a warp factor emerges dynamically and naturally. We present nonsupersymmetric models in which the potential for the link fields has translational invariance, broken only by boundary effects that trigger an exponential profile of vacuum expectation values. The spectrum of physical states deviates exponentially from that of the continuum for large masses; we discuss the effects of such exponential towers on gauge coupling unification. We also present a supersymmetric example in which a warp factor is driven by Fayet-Iliopoulos terms. The model is peculiar in that it possesses a global supersymmetry that remains unbroken despite nonvanishing D-terms. Inclusion of gravity and/or additional messenger fields leads to the collective breaking of supersymmetry and to unusual phenomenology.Comment: 28 pages LaTeX, JHEP format, 7 eps figures (v2: reference added

    Development and Validation of the Five-Factor LAMBI Measure of God Representations

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    God representations are complex and there is no standard, relatively short, and easy to administer measure reflecting both anthropomorphic and abstract representations of God. We developed a new measure with five dimensions: Limitless, Authoritarian, Mystical, Benevolent, and Ineffable (the LAMBI scale). In Study 1, we used exploratory factor analysis to examine the factor structure of a preliminary list of 41 common adjectives that people might use to describe God. In Study 2, we identified the 25 best-fitting items, using confirmatory factor analysis to show that a five-factor model fit well, and began to validate the new scale using measures of religious commitment, individualistic spirituality, and Quest. In Study 3, we found the scale has good test-retest reliability. In Study 4, we examined the contribution of the LAMBI scales in predicting conservatism, values, and beliefs, above and beyond two existing measures of God representations. In Study 5, we used latent profile analysis to identify four response patterns across the five dimensions: Relational, Abstract, Unbelief, and Amorphous (no differences across the five dimensions) and show little relation between these profiles and religious group membership. We conclude that the LAMBI scale assesses important individual differences in thinking about God and can potentially be used to predict beliefs and social attitudes

    Predicate Abstraction for Linked Data Structures

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    We present Alias Refinement Types (ART), a new approach to the verification of correctness properties of linked data structures. While there are many techniques for checking that a heap-manipulating program adheres to its specification, they often require that the programmer annotate the behavior of each procedure, for example, in the form of loop invariants and pre- and post-conditions. Predicate abstraction would be an attractive abstract domain for performing invariant inference, existing techniques are not able to reason about the heap with enough precision to verify functional properties of data structure manipulating programs. In this paper, we propose a technique that lifts predicate abstraction to the heap by factoring the analysis of data structures into two orthogonal components: (1) Alias Types, which reason about the physical shape of heap structures, and (2) Refinement Types, which use simple predicates from an SMT decidable theory to capture the logical or semantic properties of the structures. We prove ART sound by translating types into separation logic assertions, thus translating typing derivations in ART into separation logic proofs. We evaluate ART by implementing a tool that performs type inference for an imperative language, and empirically show, using a suite of data-structure benchmarks, that ART requires only 21% of the annotations needed by other state-of-the-art verification techniques

    Multi-Element Abundance Measurements from Medium-Resolution Spectra. II. Catalog of Stars in Milky Way Dwarf Satellite Galaxies

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    We present a catalog of Fe, Mg, Si, Ca, and Ti abundances for 2961 red giant stars that are likely members of eight dwarf satellite galaxies of the Milky Way (MW): Sculptor, Fornax, Leo I, Sextans, Leo II, Canes Venatici I, Ursa Minor, and Draco. For the purposes of validating our measurements, we also observed 445 red giants in MW globular clusters and 21 field red giants in the MW halo. The measurements are based on Keck/DEIMOS medium-resolution spectroscopy combined with spectral synthesis. We estimate uncertainties in [Fe/H] by quantifying the dispersion of [Fe/H] measurements in a sample of stars in monometallic globular clusters. We estimate uncertainties in Mg, Si, Ca, and Ti abundances by comparing our medium-resolution spectroscopic measurements to high-resolution spectroscopic abundances of the same stars. For this purpose, our DEIMOS sample included 132 red giants with published high-resolution spectroscopy in globular clusters, the MW halo field, and dwarf galaxies. The standard deviations of the differences in [Fe/H] and [alpha/Fe] (the average of [Mg/Fe], [Si/Fe], [Ca/Fe], and [Ti/Fe]) between the two samples is 0.15 and 0.16, respectively. This catalog represents the largest sample of multi-element abundances in dwarf galaxies to date. The next papers in this series draw conclusions on the chemical evolution, gas dynamics, and star formation histories from the catalog presented here. The wide range of dwarf galaxy luminosity reveals the dependence of dwarf galaxy chemical evolution on galaxy stellar mass.Comment: 26 pages, 22 figures, 4 machine-readable tables (available in the source file; click "Other formats"); accepted for publication in ApJ Supplements; updated acknowledgments in v

    Black Diamonds at Brane Junctions

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    We discuss the properties of black holes in brane-world scenarios where our universe is viewed as a four-dimensional sub-manifold of some higher-dimensional spacetime. We consider in detail such a model where four-dimensional spacetime lies at the junction of several domain walls in a higher dimensional anti-de Sitter spacetime. In this model there may be any number p of infinitely large extra dimensions transverse to the brane-world. We present an exact solution describing a black p-brane which will induce on the brane-world the Schwarzschild solution. This exact solution is unstable to the Gregory-Laflamme instability, whereby long-wavelength perturbations cause the extended horizon to fragment. We therefore argue that at late times a non-rotating uncharged black hole in the brane-world is described by a deformed event horizon in p+4 dimensions which will induce, to good approximation, the Schwarzschild solution in the four-dimensional brane world. When p=2, this deformed horizon resembles a black diamond and more generally for p>2, a polyhedron.Comment: 13 pages, 1 figure, latex, JHEP.cl
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