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Serotonin Syndrome versus Cannabis Toxicity in the Emergency Department
As more states legalize marijuana, the potential of marijuana abuse could lead to an increase in the number of emergency department (ED) visits. We describe two patients who presented to the ED with dilated pupils, rigidity in both lower extremities, and clonus in both feet after inhaling the vapor of a highly potent form of marijuana. Serotonin syndrome diagnosis was initially considered in the differential diagnosis. Ultimately, high-potency marijuana abuse was the final diagnosis. Therefore, marijuana toxicity should be considered in ED patients who present with signs and symptoms similar to that of serotonin syndrome
Production of quark pairs from classical gluon fields
We compute by numerical integration of the Dirac equation the number of
quark-antiquark pairs produced in the classical color fields of colliding
ultrarelativistic nuclei. Results for the dependence of the number of quarks on
the strength of the background field, the quark mass and time are presented. We
also perform several tests of our numerical method. While the number of qqbar
pairs is parametrically suppressed in the coupling constant, we find that in
this classical field model it could even be compatible with the thermal ratio
to the number of gluons.Comment: 8 pages, 12 figures, contribution to the proceedings of the Quark
Gluon Plasma Thermalization Workshop, Vienna, August 200
Quark-antiquark production from classical fields and chemical equilibration
We compute by numerical integration of the Dirac equation the number of
quark-antiquark pairs produced in the classical color fields of colliding
ultrarelativistic nuclei. The backreaction of the created pairs on the color
fields is not taken into account. While the number of qqbar pairs is
parametrically suppressed in the coupling constant, we find that in this
classical field model it could even be compatible with the thermal ratio to the
number of gluons. After isotropization one could thus have quark-gluon plasma
in chemical equilibrium.Comment: 4 pages, 6 figures, contribution to proceedings of Quark Matter 2005,
Budapest, Aug 4-
Ground-based variability surveys towards Centaurus A: worthwhile or not?
Context: Difference imaging has proven to be a powerful technique for
detecting and monitoring the variability of unresolved stellar sources in M 31.
Using this technique in surveys of galaxies outside the Local Group could have
many interesting applications. Aims: The goal of this paper is to test
difference imaging photometry on Centaurus A, the nearest giant elliptical
galaxy, at a distance of 4 Mpc. Methods: We obtained deep photometric data with
the Wide Field Imager at the ESO/MPG 2.2m at La Silla spread over almost two
months. Applying the difference imaging photometry package DIFIMPHOT, we
produced high-quality difference images and detected variable sources. The
sensitivity of the current observational setup was determined through
artificial residual tests. Results: In the resulting high-quality difference
images, we detect 271 variable stars. We find a difference flux detection limit
corresponding to m_R~24.5. Based on a simple model of the halo of Centaurus A,
we estimate that a ground-based microlensing survey would detect in the order
of 4 microlensing events per year due to lenses in the halo. Conclusions:
Difference imaging photometry works very well at the distance of Centaurus A
and promises to be a useful tool for detecting and studying variable stars in
galaxies outside the local group. For microlensing surveys, a higher
sensitivity is needed than achieved here, which would be possible with a large
ground-based telescope or space observatory with wide-field imaging
capabilities.Comment: 8 pages, 7 figures, accepted for publication in Astronomy and
Astrophysic
Multipole Expansion for Relativistic Coulomb Excitation
We derive a general expression for the multipole expansion of the
electro-magnetic interaction in relativistic heavy-ion collisions, which can be
employed in higher-order dynamical calculations of Coulomb excitation. The
interaction has diagonal as well as off-diagonal multipole components,
associated with the intrinsic and relative coordinates of projectile and
target. A simple truncation in the off-diagonal components gives excellent
results in first-order perturbation theory for distant collisions and for beam
energies up to 200 MeV/nucleon.Comment: 3 figures, Accepted for publication in Phys. Rev.
Solar Neutrinos and the Eclipse Effect
The solar neutrino counting rate in a real time detector like
Super--Kamiokanda, SNO, or Borexino is enhanced due to neutrino oscillations in
the Moon during a partial or total solar eclipse. The enhancement is calculated
as a function of the neutrino parameters in the case of three flavor mixing.
This enhancement, if seen, can further help to determine the neutrino
parameters.Comment: 24 Pages Revtex, 8 figures as one ps file. To appear in Phys. Rev. D;
Some typos corrected and a reference adde
Antiferromagnetic spintronics
Antiferromagnetic materials could represent the future of spintronic
applications thanks to the numerous interesting features they combine: they are
robust against perturbation due to magnetic fields, produce no stray fields,
display ultrafast dynamics and are capable of generating large
magneto-transport effects. Intense research efforts over the past decade have
been invested in unraveling spin transport properties in antiferromagnetic
materials. Whether spin transport can be used to drive the antiferromagnetic
order and how subsequent variations can be detected are some of the thrilling
challenges currently being addressed. Antiferromagnetic spintronics started out
with studies on spin transfer, and has undergone a definite revival in the last
few years with the publication of pioneering articles on the use of spin-orbit
interactions in antiferromagnets. This paradigm shift offers possibilities for
radically new concepts for spin manipulation in electronics. Central to these
endeavors are the need for predictive models, relevant disruptive materials and
new experimental designs. This paper reviews the most prominent spintronic
effects described based on theoretical and experimental analysis of
antiferromagnetic materials. It also details some of the remaining bottlenecks
and suggests possible avenues for future research
Supersymmetry and the Cosmic Ray Positron Excess
We explore several supersymmetric alternatives to explain predictions for the
cosmic ray positron excess. Light sneutrino or neutralino LSP's, and a
fine-tuned model designed to provide a delta-function input, can give adequate
statistical descriptions of the reported HEAT data if non-thermal production of
the relic cold dark matter density dominates and/or if ``boost factors''(that
could originate in uncertainties from propagation or local density
fluctuations) to increase the size of the signal are included. All the
descriptions can be tested at the Tevatron or LHC, and some in other WIMP
detecting experiments.Comment: 15 pages, 3 figure
HST Imaging of MEGA Microlensing Candidates in M31
We investigate /ACS and WFPC2 images at the positions of five candidate
microlensing events from a large survey of variability in M31 (MEGA). Three
closely match unresolved sources, and two produce only flux upper limits. All
are confined to regions of the color-magnitude diagram where stellar
variability is unlikely to be easily confused with microlensing. Red variable
stars cannot explain these events (although background supernova are possible
for two). If these lenses arise in M31's halo, they are due to masses (95% certainty, for a -function mass distribution),
brown dwarfs for disk lenses, and stellar masses for bulge lenses.Comment: Accepted for publication in ApJL. Higher resolution version available
at http://www.astro.columbia.edu/~patrick/hst/hst_ml.pd
Temperature dependence of polarization relaxation in semiconductor quantum dots
The decay time of the linear polarization degree of the luminescence in
strongly confined semiconductor quantum dots with asymmetrical shape is
calculated in the frame of second-order quasielastic interaction between
quantum dot charge carriers and LO phonons. The phonon bottleneck does not
prevent significantly the relaxation processes and the calculated decay times
can be of the order of a few tens picoseconds at temperature K,
consistent with recent experiments by Paillard et al. [Phys. Rev. Lett.
{\bf86}, 1634 (2001)].Comment: 4 pages, 4 figure
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