18,798 research outputs found
Deformed General Relativity and Effective Actions from Loop Quantum Gravity
Canonical methods can be used to construct effective actions from deformed
covariance algebras, as implied by quantum-geometry corrections of loop quantum
gravity. To this end, classical constructions are extended systematically to
effective constraints of canonical quantum gravity and applied to model systems
as well as general metrics, with the following conclusions: (i) Dispersion
relations of matter and gravitational waves are deformed in related ways,
ensuring a consistent realization of causality. (ii) Inverse-triad corrections
modify the classical action in a way clearly distinguishable from curvature
effects. In particular, these corrections can be significantly larger than
often expected for standard quantum-gravity phenomena. (iii) Finally, holonomy
corrections in high-curvature regimes do not signal the evolution from collapse
to expansion in a "bounce," but rather the emergence of the universe from
Euclidean space at high density. This new version of signature-change cosmology
suggests a natural way of posing initial conditions, and a solution to the
entropy problem.Comment: 44 page
Statutory Limitation of Innkeepers\u27 Liability
Many of the earliest cases of which reports are extant deal with the liability of the innkeeper to his guest, and the earliest known Roman law gave an action against the innkeeper if the baggage of the guest was in any way damaged, lost or stolen. At common law the innkeeper was the insurer of the baggage of his guest. He was under an absolute liability unless he could prove that the loss was caused by an Act of God, the public enemy, by the act of the guest or of the guest\u27s servants. This absolute liability was extended to include all movable goods, and even those goods upon which a felony could not be committed. The Washington Court has fully approved of this common law rule and has applied it strictly. This stringent rule of the common law developed through necessity. There being many ruffians and robbers abroad at night throughout the land, the wayfarer had to put up at an inn or else likely suffer the loss of all his goods and possibly his life. Often the innkeeper was sorely tempted to cast his lot with that of the highwayman, with the natural result that the traveler could never feel secure. This led to the common law placing an absolute liability upon the innkeeper, thus taking all the profits out of such conspiracy with the highwayman
Accelerated epigenetic aging in Werner syndrome.
Individuals suffering from Werner syndrome (WS) exhibit many clinical signs of accelerated aging. While the underlying constitutional mutation leads to accelerated rates of DNA damage, it is not yet known whether WS is also associated with an increased epigenetic age according to a DNA methylation based biomarker of aging (the "Epigenetic Clock"). Using whole blood methylation data from 18 WS cases and 18 age matched controls, we find that WS is associated with increased extrinsic epigenetic age acceleration (p=0.0072) and intrinsic epigenetic age acceleration (p=0.04), the latter of which is independent of age-related changes in the composition of peripheral blood cells. A multivariate model analysis reveals that WS is associated with an increase in DNA methylation age (on average 6.4 years, p=0.011) even after adjusting for chronological age, gender, and blood cell counts. Further, WS might be associated with a reduction in naïve CD8+ T cells (p=0.025) according to imputed measures of blood cell counts. Overall, this study shows that WS is associated with an increased epigenetic age of blood cells which is independent of changes in blood cell composition. The extent to which this alteration is a cause or effect of WS disease phenotypes remains unknown
Cup products in the etale cohomology of number fields
This paper concerns cup product pairings in \'etale cohomology related to
work of M. Kim and of W. McCallum and R. Sharifi. We will show that by
considering Ext groups rather than cohomology groups, one arrives at a pairing
which combines invariants defined by Kim with a pairing defined by McCallum and
Sharifi. We also prove a formula for Kim's invariant in terms of Artin maps in
the case of cyclic unramified Kummer extensions. One consequence is that for
all , there are infinitely many number fields over which there are
both trivial and non-trivial Kim invariants associated to cyclic groups of
order .Comment: 21 pages; in version 3 we changed the title of the paper and we
restructured the pape
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