14,234 research outputs found
Juries and Justice: Are Malpractice and Other Personal Injuries Created Equal?
A study analyzed the civil jury system and the difference in personal injury awards between automobile and deep-pocket defendants, especially in medical malpractice cases. Six conclusions were reached, including the finding that juries sometimes respond emotionally and award some objectively similar cases higher damages than others
Quantifying Resources in General Resource Theory with Catalysts
© 2018 American Physical Society. A question that is commonly asked in all areas of physics is how a certain property of a physical system can be used to achieve useful tasks and how to quantify the amount of such a property in a meaningful way. We answer this question by showing that, in a general resource-theoretic framework that allows the use of free states as catalysts, the amount of "resources" contained in a given state, in the asymptotic scenario, is equal to the regularized relative entropy of a resource of that state. While we need to place a few assumptions on our resource-theoretical framework, it is still sufficiently general, and its special cases include quantum resource theories of entanglement, coherence, asymmetry, athermality, nonuniformity, and purity. As a by-product, our result also implies that the amount of noise one has to inject locally to erase all the entanglement contained in an entangled state is equal to the regularized relative entropy of entanglement
An upper limit for the water outgassing rate of the main-belt comet 176P/LINEAR observed with Herschel/HIFI
176P/LINEAR is a member of the new cometary class known as main-belt comets
(MBCs). It displayed cometary activity shortly during its 2005 perihelion
passage that may be driven by the sublimation of sub-surface ices. We have
therefore searched for emission of the H2O 110-101 ground state rotational line
at 557 GHz toward 176P/LINEAR with the Heterodyne Instrument for the Far
Infrared (HIFI) on board the Herschel Space Observatory on UT 8.78 August 2011,
about 40 days after its most recent perihelion passage, when the object was at
a heliocentric distance of 2.58 AU. No H2O line emission was detected in our
observations, from which we derive sensitive 3-sigma upper limits for the water
production rate and column density of < 4e25 molec/s and of < 3e10 cm^{-2},
respectively. From the peak brightness measured during the object's active
period in 2005, this upper limit is lower than predicted by the relation
between production rates and visual magnitudes observed for a sample of comets
by Jorda et al. (2008) at this heliocentric distance. Thus, 176P/LINEAR was
likely less active at the time of our observation than during its previous
perihelion passage. The retrieved upper limit is lower than most values derived
for the H2O production rate from the spectroscopic search for CN emission in
MBCs.Comment: 5 pages, 2 figures. Minor changes to match published versio
Control landscapes for two-level open quantum systems
A quantum control landscape is defined as the physical objective as a
function of the control variables. In this paper the control landscapes for
two-level open quantum systems, whose evolution is described by general
completely positive trace preserving maps (i.e., Kraus maps), are investigated
in details. The objective function, which is the expectation value of a target
system operator, is defined on the Stiefel manifold representing the space of
Kraus maps. Three practically important properties of the objective function
are found: (a) the absence of local maxima or minima (i.e., false traps); (b)
the existence of multi-dimensional sub-manifolds of optimal solutions
corresponding to the global maximum and minimum; and (c) the connectivity of
each level set. All of the critical values and their associated critical
sub-manifolds are explicitly found for any initial system state. Away from the
absolute extrema there are no local maxima or minima, and only saddles may
exist, whose number and the explicit structure of the corresponding critical
sub-manifolds are determined by the initial system state. There are no saddles
for pure initial states, one saddle for a completely mixed initial state, and
two saddles for other initial states. In general, the landscape analysis of
critical points and optimal manifolds is relevant to the problem of explaining
the relative ease of obtaining good optimal control outcomes in the laboratory,
even in the presence of the environment.Comment: Minor editing and some references adde
Validation of nonlinear PCA
Linear principal component analysis (PCA) can be extended to a nonlinear PCA
by using artificial neural networks. But the benefit of curved components
requires a careful control of the model complexity. Moreover, standard
techniques for model selection, including cross-validation and more generally
the use of an independent test set, fail when applied to nonlinear PCA because
of its inherent unsupervised characteristics. This paper presents a new
approach for validating the complexity of nonlinear PCA models by using the
error in missing data estimation as a criterion for model selection. It is
motivated by the idea that only the model of optimal complexity is able to
predict missing values with the highest accuracy. While standard test set
validation usually favours over-fitted nonlinear PCA models, the proposed model
validation approach correctly selects the optimal model complexity.Comment: 12 pages, 5 figure
Stabilization of Multiple Robots on Stable Orbits via Local Sensing
We develop decentralized controllers for a team of disk-shaped robots to converge to and circulate along the boundary of a desired two-dimensional geometric pattern specified by a smooth function with collision avoidance. The proposed feedback controllers rely solely on each robot\u27s range and bearing sensors which allow them to obtain information about positions of neighbors within a given range. This is relevant for applications such as perimeter surveillance or containing hazardous regions where limited bandwidth must be preserved for situational awareness. The computational complexity of the decentralized controller for each agent is linear in the number of neighboring agents, making it scalable to robot swarms. We establish stability and convergence properties of the controllers and verify the feasibility of the method through computer simulations
Don't bleach chaotic data
A common first step in time series signal analysis involves digitally
filtering the data to remove linear correlations. The residual data is
spectrally white (it is ``bleached''), but in principle retains the nonlinear
structure of the original time series. It is well known that simple linear
autocorrelation can give rise to spurious results in algorithms for estimating
nonlinear invariants, such as fractal dimension and Lyapunov exponents. In
theory, bleached data avoids these pitfalls. But in practice, bleaching
obscures the underlying deterministic structure of a low-dimensional chaotic
process. This appears to be a property of the chaos itself, since nonchaotic
data are not similarly affected. The adverse effects of bleaching are
demonstrated in a series of numerical experiments on known chaotic data. Some
theoretical aspects are also discussed.Comment: 12 dense pages (82K) of ordinary LaTeX; uses macro psfig.tex for
inclusion of figures in text; figures are uufile'd into a single file of size
306K; the final dvips'd postscript file is about 1.3mb Replaced 9/30/93 to
incorporate final changes in the proofs and to make the LaTeX more portable;
the paper will appear in CHAOS 4 (Dec, 1993
Decoupling social status and status certainty effects on health in macaques: a network approach.
BackgroundAlthough a wealth of literature points to the importance of social factors on health, a detailed understanding of the complex interplay between social and biological systems is lacking. Social status is one aspect of social life that is made up of multiple structural (humans: income, education; animals: mating system, dominance rank) and relational components (perceived social status, dominance interactions). In a nonhuman primate model we use novel network techniques to decouple two components of social status, dominance rank (a commonly used measure of social status in animal models) and dominance certainty (the relative certainty vs. ambiguity of an individual's status), allowing for a more complex examination of how social status impacts health.MethodsBehavioral observations were conducted on three outdoor captive groups of rhesus macaques (N = 252 subjects). Subjects' general physical health (diarrhea) was assessed twice weekly, and blood was drawn once to assess biomarkers of inflammation (interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP)).ResultsDominance rank alone did not fully account for the complex way that social status exerted its effect on health. Instead, dominance certainty modified the impact of rank on biomarkers of inflammation. Specifically, high-ranked animals with more ambiguous status relationships had higher levels of inflammation than low-ranked animals, whereas little effect of rank was seen for animals with more certain status relationships. The impact of status on physical health was more straightforward: individuals with more ambiguous status relationships had more frequent diarrhea; there was marginal evidence that high-ranked animals had less frequent diarrhea.DiscussionSocial status has a complex and multi-faceted impact on individual health. Our work suggests an important role of uncertainty in one's social status in status-health research. This work also suggests that in order to fully explore the mechanisms for how social life influences health, more complex metrics of social systems and their dynamics are needed
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