1,071 research outputs found
Possible observation of phase separation near a quantum phase transition in doubly connected ultrathin superconducting cylinders of aluminum
The kinetic energy of superconducting electrons in an ultrathin, doubly
connected superconducting cylinder, determined by the applied flux, increases
as the cylinder diameter decreases, leading to a destructive regime around
half-flux quanta and a superconductor to normal metal quantum phase transition
(QPT). Regular step-like features in resistance vs. temperature curves taken at
fixed flux values were observed near the QPT in ultrathin Al cylinders. It is
proposed that these features are most likely resulted from a phase separation
near the QPT in which normal regions nucleate in a homogeneous superconducting
cylinder.Comment: 4 pages, 4 figures, to appear in Phys. Rev. Let
Anatomic Relationships Between the Coronary Venous System, Surrounding Structures, and the Site of Origin of Epicardial Ventricular Arrhythmias
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109967/1/jce12497.pd
A Framework to Manage the Complex Organisation of Collaborating: Its Application to Autonomous Systems
In this paper we present an analysis of the complexities of large group
collaboration and its application to develop detailed requirements for
collaboration schema for Autonomous Systems (AS). These requirements flow from
our development of a framework for collaboration that provides a basis for
designing, supporting and managing complex collaborative systems that can be
applied and tested in various real world settings. We present the concepts of
"collaborative flow" and "working as one" as descriptive expressions of what
good collaborative teamwork can be in such scenarios. The paper considers the
application of the framework within different scenarios and discuses the
utility of the framework in modelling and supporting collaboration in complex
organisational structures
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Detecting, Locating, and Characterizing Remote Power Sources
A feasibility study to determine range and back-azimuth detection methods for an isolated generator powering common loads was completed. The study deployed 3-component E and B field sensors with sampling rates of 100 kHz in a low noise test location in Southern California. Scripted power and load cycling was recorded at ranges of 40 meters to 4 km from the generator/load source. Three loads were tested: a 100 meter string of lights, an inverter powering an air blower, and a resistive heater. No E-field or B-field radiated signals were detected at ranges greater than 40 meters with a signal-to-noise ratio greater than one. Large variations in the broadband background electromagnetic noise were observed and may have been responsible for null detections at some measurement locations. At the 40-meter station, a frequency shift upon generator loading was observed for all load types. Harmonics from the detuned generator (operating at 56.7 Hz) could be observed for all load types but were most pronounced for the inverter source. A back-azimuth estimation methodology was applied to detected harmonics with stable and consistent results. For the inverter source, consistent back azimuths to the source were determined for the fundamental and higher detected harmonics up to the 31st. The method was applied to narrow band ''noise'' at 60 Hz and produced bimodal directions that roughly pointed to large population centers. Details of the method are withheld in this report pending a record of invention submittal. Although the generator/load combinations, which utilized wiring that tended to minimize stray signals, cannot yet be detected at large stand-off range without application of noise-filtering methods, the back-azimuth method appears promising and should be applied to other source types and frequency ranges where an E and B field can be detected. A record of invention describing this new back-azimuth method has been submitted to the Intellectual Property Law Group
Here one year, gone the next? Investigating persistence of frequent emergency department attendance: a retrospective study in Australia
Objectives Patients are presenting to emergency departments (EDs) with increasing complexity at rates beyond population growth and ageing. Intervention studies target patients with 12 months or less of frequent attendance. However, these interventions are not well targeted since most patients do not remain frequent attenders. This paper quantifies temporary and ongoing frequent attendance and contrasts risk factors for each group.
Design Retrospective population-based study using 10 years of longitudinal data.
Setting An Australian geographic region that includes metropolitan and rural EDs.
Participants 332â100 residents visited any ED during the study period.
Main outcome measure Frequent attendance was defined as seven or more visits to any ED in the region within a 12-month period. Temporary frequent attendance was defined as meeting this threshold only once, and ongoing more than once. Risk factors for temporary and ongoing frequent attenders were identified using logistic regression models for adults and children.
Results Of 8577 frequent attenders, 80.1% were temporary and 19.9% ongoing (12.9% repeat, 7.1% persistent). Among adults, ongoing were more likely than temporary frequent attenders to be young to middle aged (aged 25-64 years), and less likely to be from a high socioeconomic area or be admitted. Ongoing frequent attenders had higher rates of non-injury presentations, in particular substance-related (OR=2.5, 99%âCI 1.1 to 5.6) and psychiatric illness (OR=2.9, 99%âCI 1.8 to 4.6). In comparison, children who were ongoing were more likely than temporary frequent attenders to be aged 5-15 years, and were not more likely to be admitted (OR=2.7, 99%âCI 0.7 to 10.9).
Conclusions Future intervention studies should distinguish between temporary and ongoing frequent attenders, develop specific interventions for each group and include rigorous evaluation
Improved Experimental Limits on the Production of Magnetic Monopoles
We present new limits on low mass accelerator-produced point-like Dirac
magnetic monopoles trapped and bound in matter surrounding the D\O collision
region of the Tevatron at Fermilab (experiment E-882). In the context of a
Drell-Yan mechanism, we obtain cross section limits for the production of
monopoles with magnetic charge values of 1, 2, 3, and 6 times the minimum Dirac
charge of the order of picobarns, some hundred times smaller than found in
similar previous Fermilab searches. Mass limits inferred from these cross
section limits are presented.Comment: 5 pages, 4 eps figures, REVTe
Pion-Muon Asymmetry Revisited
Long ago an unexpected and unexplainable phenomena was observed. The
distribution of muons from positive pion decay at rest was anisotropic with an
excess in the backward direction relative to the direction of the proton beam
from which the pions were created. Although this effect was observed by several
different groups with pions produced by different means, the result was not
accepted by the physics community, because it is in direct conflict with a
large set of other experiments indicating that the pion is a pseudoscalar
particle. It is possible to satisfy both sets of experiments if helicity-zero
vector particles exist and the pion is such a particle. Helicity-zero vector
particles have direction but no net spin. For the neutral pion to be a vector
particle requires an additional modification to conventional theory as
discussed herein. An experiment is proposed which can prove that the asymmetry
in the distribution of muons from pion decay is a genuine physical effect
because the asymmetry can be modified in a controllable manner. A positive
result will also prove that the pion is NOT a pseudoscalar particle.Comment: 9 pages, 3 figure
PSR J1856+0245: Arecibo Discovery of a Young, Energetic Pulsar Coincident with the TeV Gamma-ray Source HESS J1857+026
We present the discovery of the Vela-like radio pulsar J1856+0245 in the
Arecibo PALFA survey. PSR J1856+0245 has a spin period of 81ms, a
characteristic age of 21kyr, and a spin-down luminosity Edot = 4.6 x 10^36
ergs/s. It is positionally coincident with the TeV gamma-ray source HESS
J1857+026, which has no other known counterparts. Young, energetic pulsars
create wind nebulae, and more than a dozen pulsar wind nebulae have been
associated with very-high-energy (100GeV-100TeV) gamma-ray sources discovered
with the HESS telescope. The gamma-ray emission seen from HESS J1857+026 is
potentially produced by a pulsar wind nebula powered by PSR J1856+0245; faint
X-ray emission detected by ASCA at the pulsar's position supports this
hypothesis. The inferred gamma-ray efficiency is epsilon_gamma = L_gamma/Edot =
3.1% (1-10TeV, for a distance of 9kpc), comparable to that observed in similar
associations.Comment: 13 pages, 1 figure, accepted for publication in The Astrophysical
Journal Letter
An Exploratory Study into the Factors Impeding Ethical Consumption
Although consumers are increasingly engaged with ethical factors when forming opinions about products and making purchase decisions, recent studies have highlighted significant differences between consumersâ intentions to consume ethically, and their actual purchase behaviour. This article contributes to an understanding of this âethical purchasing gapâ through a review of existing literature, and the inductive analysis of focus group discussions. A model is suggested which includes exogenous variables such as moral maturity and age which have been well covered in the literature, together with further impeding factors identified from the focus group discussions. For some consumers, inertia in purchasing behaviour was such that the decision-making process was devoid of ethical considerations. Several manifested their ethical views through post-purchase dissonance and retrospective feelings of guilt. Others displayed a reluctance to consume ethically due to personal constraints, a perceived negative impact on image or quality, or an outright negation of responsibility. Those who expressed a desire to consume ethically often seemed deterred by cynicism, which caused them to question the impact they, as an individual, could achieve. These findings enhance the understanding of ethical consumption decisions and provide a platform for future research in this area
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