198,844 research outputs found
Calcified amorphous tumor: A rare cause of central retinal artery occlusion.
PurposeWe report the case of a central retinal artery occlusion secondary to presumed embolus from a calcified amorphous tumor of the heart, a very rare non-neoplastic cardiac mass.ObservationsA 60-year-old female presented with acute unilateral vision loss of the left eye. Examination revealed hand motion visual acuity of the left eye and a left relative afferent pupillary defect. Fundoscopy showed whitening of the macula with a cherry red spot, consistent with a central retinal artery occlusion. Initial workup was unremarkable, including hypercoagulability labs, magnetic resonance imaging of the brain, and magnetic resonance angiography of the head and neck. Transthoracic echocardiogram (TTE) showed calcification of the mitral valve but no masses. Subsequently, transesophageal echocardiogram (TEE) was performed, which revealed a mobile calcified amorphous tumor of the heart.ConclusionsCalcified amorphous tumor of the heart is a very rare cardiac mass that may cause retinal artery occlusion. TEE is a more sensitive imaging modality to assess for potential cardio-embolic sources if TTE is unrevealing
Alternative schemes for measurement-device-independent quantum key distribution
Practical schemes for measurement-device-independent quantum key distribution
using phase and path or time encoding are presented. In addition to immunity to
existing loopholes in detection systems, our setup employs simple encoding and
decoding modules without relying on polarization maintenance or optical
switches. Moreover, by employing a modified sifting technique to handle the
dead-time limitations in single-photon detectors, our scheme can be run with
only two single-photon detectors. With a phase-postselection technique, a
decoy-state variant of our scheme is also proposed, whose key generation rate
scales linearly with the channel transmittance.Comment: 30 pages, 5 figure
The evolution-dominated hydrodynamic model and the pseudorapidity distributions in high energy physics
By taking into account the effects of leading particles, we discuss the
pseudorapidity distributions of the charged particles produced in high energy
heavy ion collisions in the context of evolution-dominated hydrodynamic model.
The leading particles are supposed to have a Gaussian rapidity distribution
normalized to the number of participants. A comparison is made between the
theoretical results and the experimental measurements performed by BRAHMS and
PHOBOS Collaboration at BNL-RHIC in Au-Au and Cu-Cu collisions at sqrt(s_NN)
=200 GeV and by ALICE Collaboration at CERN-LHC in Pb-Pb collisions at
sqrt(s_NN) =2.76 TeV.Comment: 17 pages,4 figures, 2 table
Complete relativistic equation of state for neutron stars
We construct the equation of state (EOS) in a wide density range for neutron
stars using the relativistic mean field theory. The properties of neutron star
matter with both uniform and non-uniform distributions are studied
consistently. The inclusion of hyperons considerably softens the EOS at high
densities. The Thomas-Fermi approximation is used to describe the non-uniform
matter, which is composed of a lattice of heavy nuclei. The phase transition
from uniform matter to non-uniform matter occurs around ,
and the free neutrons drip out of nuclei at about $2.4 \times 10^{-4}\
\rm{fm^{-3}}$. We apply the resulting EOS to investigate the neutron star
properties such as maximum mass and composition of neutron stars.Comment: 23 pages, REVTeX, 9 ps figures, to appear in Phys. Rev.
Heavy top quark from Fritzsch mass matrices
It is shown, contrary to common belief, that the Fritzsch ansatz for the
quark mass matrices admits a heavy top quark. With the ansatz prescribed at the
supersymmetric grand unified (GUT) scale, one finds that the top quark may be
as heavy as 145 GeV, provided that tan (the ratio of the vacuum
expectation values of the two higgs doublets) . Within a
non-supersymmetric GUT framework with two (one) light higgs doublets, the
corresponding approximate upper bound on the top mass is GeV. Our
results are based on a general one--loop renormalization group analysis of the
quark masses and mixing angles and are readily applied to alternative mass
matrix ans\"{a}tze.Comment: LaTeX, 14 figures (not included, available on request
The effects of peer influence on adolescent pedestrian road-crossing decisions
Objective: Adolescence is a high-risk period for pedestrian injury. It is also a time of heightened susceptibility to peer influence. The aim of this research was to examine the effects of peer influence on the pedestrian road-crossing decisions of adolescents.
Methods: Using 10 videos of road-crossing sites, 80 16- to 18-year-olds were asked to make pedestrian road-crossing decisions. Participants were assigned to one of 4 experimental conditions: negative peer (influencing unsafe decisions), positive peer (influencing cautious decisions), silent peer (who observed but did not comment), and no peer (the participant completed the task alone). Peers from the adolescentâs own friendship group were recruited to influence either an unsafe or a cautious decision.
Results: Statistically significant differences were found between peer conditions. Participants least often identified safe road-crossing
sites when accompanied by a negative peer and more frequently identified dangerous road-crossing sites when accompanied by a positive peer. Both cautious and unsafe comments from a peer influenced adolescent pedestriansâ decisions.
Conclusions: These findings showed that road-crossing decisions of adolescents were influenced by both unsafe and cautious comments from their peers. The discussion highlighted the role that peers can play in both increasing and reducing adolescent risk-taking
Using Flow Cytometry to Analyze Cryptococcus Infection of Macrophages.
Flow cytometry is a powerful analytical technique, which is increasingly being used to study the interaction between host cells and intracellular pathogens. Flow cytometry is capable of measuring a greater number of infected cells within a sample compared to alternative techniques such as fluorescence microscopy. This means that robust quantification of rare events during infection is possible. Our lab and others have developed flow cytometry methods to study interactions between host cells and intracellular pathogens, such as Cryptococcus neoformans, to quantify phagocytosis, intracellular replication, and non-lytic expulsion or "vomocytosis" from the phagosome. Herein we describe these methods and how they can be applied to the study of C. neoformans as well as other similar intracellular pathogens
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