16,598 research outputs found
People Who Punish or Reward Tend to Moralize Even Conventional Behaviour
Managers who have to reward or punish
others may be prone to moralizing. This
can create problems because it may
make the manager less tolerant of
errant behavior while others in the social
group, who may be wary of moralizing
attitudes, may react against the
manager.York's Knowledge Mobilization Unit provides services and funding for faculty, graduate students, and community organizations seeking to maximize the impact of academic research and expertise on public policy, social programming, and professional practice. It is supported by SSHRC and CIHR grants, and by the Office of the Vice-President Research & Innovation.
[email protected]
www.researchimpact.c
Entanglement distribution by an arbitrarily inept delivery service
We consider the scenario where a company C manufactures in bulk pure
entangled pairs of particles, each pair intended for a distinct pair of distant
customers. Unfortunately, its delivery service is inept - the probability that
any given customer pair receives its intended particles is S, and the customers
cannot detect whether an error has occurred. Remarkably, no matter how small S
is, it is still possible for C to distribute entanglement by starting with
non-maximally entangled pairs. We determine the maximum entanglement
distributable for a given S, and also determine the ability of the parties to
perform nonlocal tasks with the qubits they receive.Comment: 5 pages, 3 figures. v2 includes minor change
The Energy Spectrum of Primary Cosmic Ray Electrons in Clusters of Galaxies and Inverse Compton Emission
Models for the evolution of the integrated energy spectrum of primary cosmic
ray electrons in clusters of galaxies have been calculated, including the
effects of losses due to inverse Compton (IC), synchrotron, and bremsstrahlung
emission, and Coulomb losses to the intracluster medium (ICM). The combined
time scale for these losses reaches a maximum of ~3e9 yr for electrons with a
Lorentz factor ~300. Only clusters in which there has been a substantial
injection of relativistic electrons since z <~ 1 will have any significant
population of primary cosmic ray electrons at present. In typical models, there
is a broad peak in the electron energy distribution extending to gamma~300, and
a steep drop in the electron population beyond this. In clusters with current
particle injection, there is a power-law tail of higher energy electrons with
an abundance determined by the current rate of injection. A significant
population of electrons with gamma~300, associated with the peak in the
particle loss time, is a generic feature of the models. The IC and synchrotron
emission from these models was calculated. In the models, EUV and soft X-ray
emission are nearly ubiquitous. This emission is produced by electrons with
gamma~300. The spectra are predicted to drop rapidly in going from the EUV to
the X-ray band. The IC emission also extends down the UV, optical, and IR bands
with a fairly flat spectrum. Hard X-ray (HXR) and diffuse radio emission due to
high energy electrons (gamma~10e4) is present only in clusters which have
current particle acceleration. Assuming that the electrons are accelerated in
ICM shocks, one would only expect diffuse HXR/radio emission in clusters which
are currently undergoing a large merger.Comment: Accepted for publication in the Astrophysical Journal, with minor
revisons to wording for clarity and one additional reference. 19 pages with
16 embedded Postscript figures in emulateapj.sty. Abbreviated abstract belo
Evaluation of the effectiveness of Eladi Keram for the treatment of acne vulgaris: a randomised controlled pilot study
Introduction: Acne is a multifactorial and common skin disease which can significantly affect the quality of life of sufferers. In this study, a topical herbal preparation traditionally used in Ayurvedic medicine was evaluated as a treatment for individuals with acne on their shoulders and backs.
Methods: Study participants were randomly assigned either to treatment (Eladi Keram) or vehicle control (coconut oil) groups under double blind conditions and instructed on its daily home application. Standardised lesion counting and acne grading were conducted in accordance with US Food and Drug Administration guidelines and with reference to the Leeds Acne Grading Technique. Participants were assessed for severity of the condition at commencement and on day 28 of treatment.
Results: The treatment group showed improvements of 42% (p < 0.005) on the Investigators Global Assessment scale, a 60% (p < 0.05) reduction in inflammatory lesions, a 59% (p < 0.05) reduction in non-inflammatory lesions, and a 59% (p < 0.005) reduction in combined lesion count. The control group showed no statistically significant changes for these criteria.
Conclusion: This study is the first reported clinical evaluation of Eladi Keram as a treatment for acne and findings suggest that it could be effective in reducing inflammatory and non-inflammatory lesions, warranting further investigation by means of a larger scale clinical trial
Turbulence and particle acceleration in collisionless supernovae remnant shocks: II- Cosmic-ray transport
Supernovae remnant shock waves could be at the origin of cosmic rays up to
energies in excess of the knee (eV) if the magnetic
field is efficiently amplified by the streaming of accelerated particles in the
shock precursor. This paper follows up on a previous paper \citep{pell05} which
derived the properties of the MHD turbulence so generated, in particular its
anisotropic character, its amplitude and its spectrum. In the present paper, we
calculate the diffusion coefficients, also accounting for compression through
the shock, and show that the predicted three-dimensional turbulence spectrum
(with and the
wavenumber components along and perpendicular to the shock normal) generally
leads to Bohm diffusion in the parallel direction. However, if the anisotropy
is constrained by a relation of the form ,
which arises when the turbulent energy cascade occurs at a constant rate
independent of scale, then the diffusion coefficient loses its Bohm scaling and
scales as in isotropic Kolmogorov turbulence. We show that these diffusion
coefficients allow to account for X-ray observations of supernova remnants.
This paper also calculates the modification of the Fermi cycle due to the
energy lost by cosmic rays in generating upstream turbulence and the
concomittant steepening of the energy spectrum. Finally we confirm that cosmic
rays can produced an amplified turbulence in young SNr during their free
expansion phase such that the maximal energy is close to the knee and the
spectral index is close to 2.3 in the warm phase of the interstellar mediumComment: 13 pages, 4 figures, accepted for publication in Astronomy &
Astrophysics main journa
The Identification of Infrared Synchrotron Radiation from Cassiopeia A
We report the discovery of polarized flux at 2.2 micron from the bright shell
of the approximately 320 year old supernova remnant Cas A. The fractional
polarizations are comparable at 6 cm and 2.2 micron, and the polarization
angles are similar, demonstrating that synchrotron radiation from the same
relativistic plasma is being observed at these widely separated wavebands. The
relativistic electrons radiating at 2.2 micron have an energy of ~ 150 GeV,
(gamma ~ 3e5), assuming an ~500 microGauss magnetic field. The total intensity
at 2.2 micron lies close to the power law extrapolation from radio frequencies,
showing that relativistic particle acceleration is likely an ongoing process;
the infrared emitting electrons were accelerated no longer than ~80 years ago.
There is a small but significant concave curvature to the spectrum, as expected
if the accelerating shocks have been modified by the back pressure of the
cosmic rays; given calibration uncertainties, this conclusion must be
considered tentative at present. The 2.2 micron polarization angles and the
emission-line filaments observed by HST are both offset from the local radial
direction by 10 - 20 degrees, providing evidence that the magnetic fields in
Cas A are generated by Rayleigh-Taylor instabilities in the decelerating
ejecta.Comment: 11 pages, 3 figures, accepted for publication Ap
Implications of Variability Patterns observed in TeV Blazars on the Structure of the Inner Jet
The recent long look X-ray observations of TeV blazars have revealed many
important new features concerning their time variability. In this paper, we
suggest a physical interpretation for those features based on the framework of
the internal and external shock scenarios. We present a simplified model
applicable to TeV blazars, and investigate through simulations how each of the
model parameters would affect to the observed light curve or spectrum. In
particular, we show that the internal shock scenario naturally leads to all the
observed variability properties including the structure function, but for it to
be applicable, the fractional fluctuation of the initial bulk Lorentz factors
must be small, with sigma_gamma / gamma_average < 0.01. This implies very low
dynamical efficiency of the internal shock scenario. We also suggest that
several observational quantities -- such as the characteristic time scale, the
relative amplitude of flares as compared to the steady (``offset'') component,
and the slope of the structure function -- can be used to probe the inner jet.
The results are applied to the TeV blazar Mrk421, and this, within the context
of the model, leads to the determination of several physical parameters: the
ejection of a shell with average thickness of ~1E13 cm occurs on average every
10 minutes, and the shells collide ~1E17 cm away from the central source.Comment: 12 pages, 13 figures, to appear in Ap
The Density Spike in Cosmic-Ray-Modified Shocks: Formation, Evolution, and Instability
We examine the formation and evolution of the density enhancement (density
spike) that appears downstream of strong, cosmic-ray-modified shocks. This
feature results from temporary overcompression of the flow by the combined
cosmic-ray shock precursor/gas subshock. Formation of the density spike is
expected whenever shock modification by cosmic-ray pressure increases strongly.
That occurence may be anticipated for newly generated strong shocks or for
cosmic-ray-modified shocks encountering a region of higher external density,
for example. The predicted mass density within the spike increases with the
shock Mach number and with shocks more dominated by cosmic-ray pressure. We
find this spike to be linearly unstable under a modified Rayleigh-Taylor
instability criterion at the early stage of its formation. We confirm this
instability numerically using two independent codes based on the two-fluid
model for cosmic-ray transport. These two-dimensional simulations show that the
instability grows impulsively at early stages and then slows down as the
gradients of total pressure and gas density decrease. Observational discovery
of this unstable density spike behind shocks, possibly through radio emission
enhanced by the amplified magnetic fields would provide evidence for the
existence of strongly cosmic-ray modified shock structures.Comment: 26 pages in Latex and 6 figures. Accepted to Ap
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