539 research outputs found
What factors inhibit learning on the part of new mothers during the postpartal stay in the hospital
Thesis (M.S.)--Boston Universit
Near-Horizon Extremal Geometries: Coadjoint Orbits and Quantization
The NHEG algebra is an extension of Virasoro introduced in
[arXiv:1503.07861]; it describes the symplectic symmetries of
-dimensional Near Horizon Extremal Geometries with isometry. In this work we construct the NHEG group and classify the
(coadjoint) orbits of its action on phase space. As we show, the group consists
of maps from an -torus to the Virasoro group, so its orbits are bundles of
standard Virasoro coadjoint orbits over . We also describe the unitary
representations that are expected to follow from the quantization of these
orbits, and display their characters. Along the way we show that the NHEG
algebra can be built from u(1) currents using a twisted Sugawara construction.Comment: 22 pages, one figure. v2: Title expanded, various minor
clarifications added. Published in JHE
Spin squeezing of atomic ensembles by multi-colour quantum non-demolition measurements
We analyze the creation of spin squeezed atomic ensembles by simultaneous
dispersive interactions with several optical frequencies. A judicious choice of
optical parameters enables optimization of an interferometric detection scheme
that suppresses inhomogeneous light shifts and keeps the interferometer
operating in a balanced mode that minimizes technical noise. We show that when
the atoms interact with two-frequency light tuned to cycling transitions the
degree of spin squeezing scales as where is the
resonant optical depth of the ensemble. In real alkali atoms there are loss
channels and the scaling may be closer to Nevertheless
the use of two-frequencies provides a significant improvement in the degree of
squeezing attainable as we show by quantitative analysis of non-resonant
probing on the Cs D1 line. Two alternative configurations are analyzed: a
Mach-Zehnder interferometer that uses spatial interference, and an interaction
with multi-frequency amplitude modulated light that does not require a spatial
interferometer.Comment: 7 figure
A systematic review of criteria used to report complications in soft tissue and oncologic surgical clinical research studies in dogs and cats.
ObjectiveTo evaluate reporting of surgical complications and other adverse events in clinical research articles describing soft tissue and oncologic surgery in dogs and cats.Study designSystematic literature review.SampleEnglish-language articles describing soft tissue and oncologic surgeries in client-owned dogs and cats published in peer-reviewed journals from 2013 to 2016.MethodsCAB, AGRICOLA, and MEDLINE databases were searched for eligible articles. Article characteristics relevant to complications were abstracted and summarized, including reported events, definitions, criteria used to classify events according to severity and time frame, and relevant citations.ResultsOne hundred fifty-one articles involving 10 522 animals were included. Canine retrospective case series of dogs predominated. Ninety-two percent of articles mentioned complications in study results, but only 7.3% defined the term complication. Articles commonly described complications according to time frame and severity, but terminology and classification criteria were highly variable, conflicting between studies, or not provided. Most (58%) reported complications could have been graded with a published veterinary adverse event classification scheme, although common intraoperative complications were notable exceptions.ConclusionDefinitions and criteria used to classify and report soft tissue and oncologic surgical complications are often absent, incomplete, or contradictory among studies.Clinical significanceLack of consistent terminology contributes to inadequate communication of important information about surgical complications. Standardization of terminology and consistency in severity scoring will improve comparative evaluation of clinical research results
HD 174005: another binary classified as lambda Boo
We demonstrate that HD 174005, a star recently classified as belonging to the
lambda Boo group, is in reality a double lined spectroscopic binary; at some
phases, the observed composite spectrum may be similar to that of a single star
with weak metal lines.Comment: Accepted by A&
Diffraction effects on light-atomic ensemble quantum interface
We present a simple method to include the effects of diffraction into the
description of a light-atomic ensemble quantum interface in the context of
collective variables. Carrying out a scattering calculation we single out the
purely geometrical effect. We apply our method to the experimentally relevant
case of Gaussian shaped atomic samples stored in single beam optical dipole
traps and probed by a Gaussian beam. We derive analytical scaling relations for
the effect of the interaction geometry and compare our findings to results from
1-dimensional models of light propagation.Comment: 13 pages, 7 figures, comments welcom
Non-Destructive Probing of Rabi Oscillations on the Cesium Clock Transition near the Standard Quantum Limit
We report on non-destructive observation of Rabi oscillations on the Cs clock
transition. The internal atomic state evolution of a dipole-trapped ensemble of
cold atoms is inferred from the phase shift of a probe laser beam as measured
using a Mach-Zehnder interferometer. We describe a single color as well as a
two-color probing scheme. Using the latter, measurements of the collective
pseudo-spin projection of atoms in a superposition of the clock states are
performed and the observed spin fluctuations are shown to be close to the
standard quantum limit.Comment: 4 pages, 4 figures, accepted for publication in Physical Review
Letter
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