645 research outputs found
Divergence of opinion and risk : an empirical analysis of the Ex Ante beliefs of institutional investors
Bibliography: p. [24-25
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Enhancing engagement in evidence-based tobacco cessation treatment for smokers with mental illness: A pilot randomized trial.
ObjectiveTo evaluate the efficacy of a brief telephone-delivered Motivational Interviewing (MI)-based intervention to facilitate engagement in evidence-based cessation treatment for Veterans with mental illness referred to smoking cessation treatment.Methods86 military Veteran smokers with mental illness were recruited from a tobacco cessation consult clinic and randomized to receive either a MI-based treatment engagement intervention (TE; n = 48) or a non-MI assessment and information control (CON; n = 38) condition. Intervention was delivered during a single brief telephone contact. Primary engagement outcomes were 1) attending a treatment session within 30 days and 2) combination treatment (attending session plus using pharmacotherapy). Cessation outcomes included self-reported 24 h cessation attempts and 7 day point abstinence at 3 months post-intervention. Outcomes were assessed at 1 and 3 months post intervention.ResultsOutcome analyses included 85 participants (47 TE, 38 CON) using an intent-to-treat analytic approach. Participants were on average 49.5 (13.4) years old, 88% Male, 59% white, 18% African American and 14% Hispanic/Latino(a). Following intervention delivery TE and CON participants did not differ on likelihood of attending a treatment session during the subsequent 30 days (47% vs 45%, respectively). A significant difference was observed when classified as utilizing combination treatment, 40% of TE versus 18% of CON reported use of smoking cessation medication and behavioral counseling (p = 0.04). No statistical differences were observed for cessation outcomes, although more TE than CON participants reported 7 day point abstinence at 3 months post-intervention (30% vs 18%).ConclusionsThe present pilot study provides initial evidence for the feasibility, acceptability and efficacy of a telephone delivered TE intervention for enhancing engagement in combinationevidence evidence-based treatment in a sample of Veteran smokers with mental illness referred to smoking cessation treatment. Smokers with mental illness typically have greater difficulty stopping smoking than those without mental illness. Increased engagement in combination treatment thus has the potential to increase quit rates and ultimately reduce the burden of tobacco use for this population
Strong atom-field coupling for Bose-Einstein condensates in an optical cavity on a chip
An optical cavity enhances the interaction between atoms and light, and the
rate of coherent atom-photon coupling can be made larger than all decoherence
rates of the system. For single atoms, this strong coupling regime of cavity
quantum electrodynamics (cQED) has been the subject of spectacular experimental
advances, and great efforts have been made to control the coupling rate by
trapping and cooling the atom towards the motional ground state, which has been
achieved in one dimension so far. For N atoms, the three-dimensional ground
state of motion is routinely achieved in atomic Bose-Einstein condensates
(BECs), but although first experiments combining BECs and optical cavities have
been reported recently, coupling BECs to strong-coupling cavities has remained
an elusive goal. Here we report such an experiment, which is made possible by
combining a new type of fibre-based cavity with atom chip technology. This
allows single-atom cQED experiments with a simplified setup and realizes the
new situation of N atoms in a cavity each of which is identically and strongly
coupled to the cavity mode. Moreover, the BEC can be positioned
deterministically anywhere within the cavity and localized entirely within a
single antinode of the standing-wave cavity field. This gives rise to a
controlled, tunable coupling rate, as we confirm experimentally. We study the
heating rate caused by a cavity transmission measurement as a function of the
coupling rate and find no measurable heating for strongly coupled BECs. The
spectrum of the coupled atoms-cavity system, which we map out over a wide range
of atom numbers and cavity-atom detunings, shows vacuum Rabi splittings
exceeding 20 gigahertz, as well as an unpredicted additional splitting which we
attribute to the atomic hyperfine structure.Comment: 20 pages. Revised version following referees' comments. Detailed
notes adde
Editorial Focus on thermoelectric effects in nanostructures
Abstract The field of nanoscale thermoelectrics began with a clear motivation for better performances of waste heat recovery processes by lowering the system dimensionality. Although this original inspiration still drives many recent developments, the field has also evolved to address fundamental questions on charge and energy transport across quantum conductors in the presence of both voltage and temperature differences. This 'focus on' collection provides new perspectives in the field and reports on the latest developments, both theoretically and experimentally. We are pleased to present a collection of 23 research papers that discuss the latest developments in the field of thermoelectric effects in nanostructures. Thermoelectrics is devoted to cross effects that lead to the generation of electric current upon the application of thermal gradients (Seebeck effect) or the manipulation of heat flow using electric fields (Peltier effect). The interest in nanoscale thermoelectrics was triggered in the early 1990s by the pioneering works of Hicks and Dresselhaus [1], who envisaged a dramatic enhancement of the energy harvesting performance by means of tailored nanostructures with high power factors and low thermal conductivity. This proposal boosted the number of both articles and patents based on small systems. Two decades later, nanothermoelectrics has firmly established as a subfield in condensed matter physics in its own right. Specifically, this community addresses now also Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI
Implementing an Insect Brain Computational Circuit Using III–V Nanowire Components in a Single Shared Waveguide Optical Network
Recent developments in photonics include efficient nanoscale optoelectronic
components and novel methods for sub-wavelength light manipulation. Here, we
explore the potential offered by such devices as a substrate for neuromorphic
computing. We propose an artificial neural network in which the weighted
connectivity between nodes is achieved by emitting and receiving overlapping
light signals inside a shared quasi 2D waveguide. This decreases the circuit
footprint by at least an order of magnitude compared to existing optical
solutions. The reception, evaluation and emission of the optical signals are
performed by a neuron-like node constructed from known, highly efficient III-V
nanowire optoelectronics. This minimizes power consumption of the network. To
demonstrate the concept, we build a computational model based on an
anatomically correct, functioning model of the central-complex navigation
circuit of the insect brain. We simulate in detail the optical and electronic
parts required to reproduce the connectivity of the central part of this
network, using experimentally derived parameters. The results are used as input
in the full model and we demonstrate that the functionality is preserved. Our
approach points to a general method for drastically reducing the footprint and
improving power efficiency of optoelectronic neural networks, leveraging the
superior speed and energy efficiency of light as a carrier of information.Comment: 28 pages, 6 figures; supplementary information 15 pages, 8 figure
Implementation of a symmetric surface electrode ion trap with field compensation using a modulated Raman effect
We describe the fabrication and characterization of a new surface-electrode Paul ion trap designed for experiments in scalable quantum information processing with Ca+. A notable feature is a symmetric electrode pattern which allows rotation of the normal modes of ion motion, yielding efficient Doppler cooling with a single beam parallel to the planar surface. We propose and implement a technique for micromotion compensation in all directions using an infrared repumper laser beam directed into the trap plane. Finally, we employ an alternate repumping scheme that increases ion fluorescence and simplifies heating rate measurements obtained by time-resolved ion fluorescence during Doppler cooling
Brainstem Shape is Affected by Clinical Course in the Neonatal Intensive Care Unit
The brainstem, critical for motor function, autonomic regulation, and many neurocognitive functions, undergoes rapid development from the third trimester. Accordingly, we hypothesized it would be vulnerable to insult during this period, and that a difficult clinical course in the neonatal intensive care unit (NICU) would affect development, and be reflected through atypical shape. Our study population consisted of 66 neonates - all inpatients from the NICU at Victoria Hospital, London Health Sciences Centre, ON, Canada, of which 45 entered the final analysis. The cohort varied in gestational age (GA) and ranged from neurologically healthy to severely brain-injured. Structural MRI was used to quantify brainstem shape at term-equivalent age. From these images, brainstems were semi-automatically segmented and co-registered across subjects. The anterior-posterior dimensions on a sagittal maximum intensity projection were used as the basis for shape comparison. Factor analysis was used to summarize variation in shape and in clinical course to determine three shape factors and three clinical factors, and their relationship assessed using correlation. A factor driven by low GA and associated complications correlated with alterations in the posterior medulla, while a factor driven by complications independent of GA correlated with alterations in the midbrain. Additionally, single clinical measures most representative of their respective clinical factor (days in NICU; days on ventilation) predicted the changes. Thus, different clinical courses in the NICU may have different effects on the shape of the brainstem, and may mediate some of the distinct neurodevelopmental profiles observed in premature and brain-injured neonates
Evaluating Affordable Cranial Ultrasonography in East African Neonatal Intensive Care Units
Neuroimaging is a valuable diagnostic tool for the early detection of neonatal brain injury, but equipment and radiologic staff are expensive and unavailable to most hospitals in developing countries. We evaluated an affordable, portable ultrasound machine as a quantitative and qualitative diagnostic tool and to establish whether a novice sonographer could effectively operate the equipment and obtain clinically important information. Cranial ultrasonography was performed on term healthy, pre-term and term asphyxiated neonates in Rwandan and Kenyan hospitals. To evaluate the detection of ventriculomegaly and compression injuries, we measured the size of the lateral ventricles and corpus callosum. The images were also assessed for the presence of other cerebral abnormalities. Measurements were reliable across images, and cases of clinically relevant ventriculomegaly were detected. A novice sonographer had good-to-excellent agreement with an expert. This study demonstrates that affordable equipment and cranial ultrasound protocols can be used in low-resource settings to assess the newborn brain
Evaluating Affordable Cranial Ultrasonography in East African Neonatal Intensive Care Units
Neuroimaging is a valuable diagnostic tool for the early detection of neonatal brain injury, but equipment and radiologic staff are expensive and unavailable to most hospitals in developing countries. We evaluated an affordable, portable ultrasound machine as a quantitative and qualitative diagnostic tool and to establish whether a novice sonographer could effectively operate the equipment and obtain clinically important information. Cranial ultrasonography was performed on term healthy, pre-term and term asphyxiated neonates in Rwandan and Kenyan hospitals. To evaluate the detection of ventriculomegaly and compression injuries, we measured the size of the lateral ventricles and corpus callosum. The images were also assessed for the presence of other cerebral abnormalities. Measurements were reliable across images, and cases of clinically relevant ventriculomegaly were detected. A novice sonographer had good-to-excellent agreement with an expert. This study demonstrates that affordable equipment and cranial ultrasound protocols can be used in low-resource settings to assess the newborn brain
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