3,674 research outputs found
Be Smart to Identify the Stroke-Like Migraine Attacks After Radiation Therapy (SMART) Syndrome
Stroke-like migraine attacks after radiation therapy (SMART) are uncommon, often occurring years or decades after brain radiation therapy. This syndrome is a diagnosis of exclusion, and only about 40 cases describing SMART have been published, each one describing a constellation of symptoms and findings. Because symptoms can arise years after initial radiation therapy, the ability of physicians to recognize SMART and rule out other possible causes of symptoms is critical for the long-term care of oncology patients who have undergone cranial radiation. Here we present the case of a 55-year-old man who experienced SMART nine years after radiation therapy and who was successfully treated with steroids
Quasi-decadal variability of Antarctic sea ice
第3回極域科学シンポジウム/第35回極域気水圏シンポジウム 11月29日(木) 国立国語研究所 2階多目的
Coefficient of restitution for elastic disks
We calculate the coefficient of restitution, , starting from a
microscopic model of elastic disks. The theory is shown to agree with the
approach of Hertz in the quasistatic limit, but predicts inelastic collisions
for finite relative velocities of two approaching disks. The velocity
dependence of is calculated numerically for a wide range of
velocities. The coefficient of restitution furthermore depends on the elastic
constants of the material via Poisson's number. The elastic vibrations absorb
kinetic energy more effectively for materials with low values of the shear
modulus.Comment: 25 pages, 12 Postscript figures, LaTex2
Gac two-component system in Pseudomonas syringae pv. tabaci is required for virulence but not for hypersensitive reaction
Pseudomonas syringae pv. tabaci 6605 causes wildfire disease on host tobacco plants. To investigate the regulatory mechanism of the expression of virulence, Gac two-Component system-defective mutants, Delta gacA and Delta gacS, and a double mutant, Delta gacA Delta gacS, were generated. These mutants produced smaller amounts of N-acyl homoserine lactones required for quorum sensing, had lost swarming motility, and had reduced expression of virulence-related hrp genes and the algT gene required for exopolysaccharide production. The ability of the mutants to cause disease symptoms in their host tobacco plant was remarkably reduced, while they retained the ability to induce hypersensitive reaction (HR) in the nonhost plants. These results indicated that the Gac two-component system of P. syringae pv. tabaci 6605 is indispensable for virulence on the host plant, but not for HR induction in the nonhost plants.</p
Phase Changes in an Inelastic Hard Disk System with a Heat Bath under Weak Gravity for Granular Fluidization
We performed numerical simulations on a two-dimensional inelastic hard disk
system under gravity with a heat bath to study the dynamics of granular
fluidization. Upon increasing the temperature of the heat bath, we found that
three phases, namely, the condensed phase, locally fluidized phase, and
granular turbulent phase, can be distinguished using the maximum packing
fraction and the excitation ratio, or the ratio of the kinetic energy to the
potential energy.It is shown that the system behavior in each phase is very
different from that of an ordinary vibrating bed.Comment: 4 pages, including 5 figure
Microcanonical Foundation for Systems with Power-Law Distributions
Starting from microcanonical basis with the principle of equal a priori
probability, it is found that, besides ordinary Boltzmann-Gibbs theory with the
exponential distribution, a theory describing systems with power-law
distributions can also be derived.Comment: 9 page
Angle of Repose and Angle of Marginal Stability: Molecular Dyanmics of Granular Particles
We present an implementation of realistic static friction in molecular
dynamics (MD) simulations of granular particles. In our model, to break
contacts between two particles, one has to apply a finite amount of force,
determined by the Coulomb criterion. Using a two dimensional model, we show
that piles generated by avalanches have a {\it finite} angle of repose
(finite slopes). Furthermore, these piles are stable under tilting
by an angle smaller than a non-zero tilting angle , showing that
is different from the angle of marginal stability ,
which is the maximum angle of stable piles. These measured angles are compared
to a theoretical approximation. We also measure by continuously
adding particles on the top of a stable pile.Comment: 14 pages, Plain Te
Topological Nature of Anomalous Hall Effect in Ferromagnet
The anomalous Hall effect in two-dimensional ferromagnets is discussed to be
the physical realization of the parity anomaly in (2+1)D, and the band crossing
points behave as the topological singularity in the Brillouin zone. This
appears as the sharp peaks and the sign changes of the transverse conductance
as a function of the Fermi energy and/or the magnetization. The
relevance to the experiments including the three dimensional systems is also
discussed.Comment: LaTeX 13 pages, 3 figure
Electronic and magnetic excitations in the "half-stuffed" Cu--O planes of BaCuOCl measured by resonant inelastic x-ray scattering
We use resonant inelastic x-ray scattering (RIXS) at the Cu L edge to
measure the charge and spin excitations in the "half-stuffed" Cu--O planes of
the cuprate antiferromagnet BaCuOCl. The RIXS line shape
reveals distinct contributions to the excitations from the two
structurally inequivalent Cu sites, which have different out-of-plane
coordinations. The low-energy response exhibits magnetic excitations. We find a
spin-wave branch whose dispersion follows the symmetry of a CuO sublattice,
similar to the case of the "fully-stuffed" planes of tetragonal CuO (T-CuO).
Its bandwidth is closer to that of a typical cuprate material, such as
SrCuOCl, than it is to that of T-CuO. We interpret this result as
arising from the absence of the effective four-spin inter-sublattice
interactions that act to reduce the bandwidth in T-CuO.Comment: 10 pages, 8 figure
- …