632 research outputs found
Sound the Alarm: Limitations of Liability in Alarm Service Contracts
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 companyâs failure to provide its service. Many customers would be surprised, though, to discover that an alarm companyâs 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 partyâs 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
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
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
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
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_â. 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 Ď_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, ă|v_(helio)ă =-382.1 Âą 2.9 km s^(-1), rules out an association with the TriangulumâAndromeda 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}_â L_â^(-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) Mâ 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
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
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
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
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
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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