1,184 research outputs found
Neck atonia with a focal stimulation-induced seizure arising from the SMA: pathophysiological considerations.
A 28-year-old patient with pharmacoresistant non-lesional right frontal epilepsy underwent extra-operative intracranial EEG recordings and electrical cortical stimulation (ECS) to map eloquent cortex. Right supplementary motor area (SMA) ECS induced a brief seizure with habitual symptoms involving neck tingling followed by asymmetric tonic posturing. An additional feature was neck atonia. During atonia and sensory aura, discharges were seen in the mesial frontal electrodes and precentral gyrus. Besides motor signs, atonia, although rare and not described in the neck muscles, and sensations have been reported with SMA stimulation. The mechanisms underlying neck atonia in seizures arising from the SMA can be explained by supplementary negative motor area (SNMA) - though this was not mapped in electrodes overlying the ictal onset zone in our patient - or primary sensorimotor cortex activation through rapid propagation. Given the broad spectrum of signs elicited by SMA stimulation and rapid spread of seizures arising from the SMA, caution should be taken to not diagnose these as non-epileptic, as had previously occurred in this patient
RegPrecise: a database of curated genomic inferences of transcriptional regulatory interactions in prokaryotes
The RegPrecise database (http://regprecise.lbl.gov) was developed for capturing, visualization and analysis of predicted transcription factor regulons in prokaryotes that were reconstructed and manually curated by utilizing the comparative genomic approach. A significant number of high-quality inferences of transcriptional regulatory interactions have been already accumulated for diverse taxonomic groups of bacteria. The reconstructed regulons include transcription factors, their cognate DNA motifs and regulated genes/operons linked to the candidate transcription factor binding sites. The RegPrecise allows for browsing the regulon collections for: (i) conservation of DNA binding sites and regulated genes for a particular regulon across diverse taxonomic lineages; (ii) sets of regulons for a family of transcription factors; (iii) repertoire of regulons in a particular taxonomic group of species; (iv) regulons associated with a metabolic pathway or a biological process in various genomes. The initial release of the database includes âŒ11 500 candidate binding sites for âŒ400 orthologous groups of transcription factors from over 350 prokaryotic genomes. Majority of these data are represented by genome-wide regulon reconstructions in Shewanella and Streptococcus genera and a large-scale prediction of regulons for the LacI family of transcription factors. Another section in the database represents the results of accurate regulon propagation to the closely related genomes
PASTIS: Bayesian extrasolar planet validation II. Constraining exoplanet blend scenarios using spectroscopic diagnoses
The statistical validation of transiting exoplanets proved to be an efficient
technique to secure the nature of small exoplanet signals which cannot be
established by purely spectroscopic means. However, the spectroscopic diagnoses
are providing us with useful constraints on the presence of blended stellar
contaminants. In this paper, we present how a contaminating star affects the
measurements of the various spectroscopic diagnoses as function of the
parameters of the target and contaminating stars using the model implemented
into the PASTIS planet-validation software. We find particular cases for which
a blend might produce a large radial velocity signal but no bisector variation.
It might also produce a bisector variation anti-correlated with the radial
velocity one, as in the case of stellar spots. In those cases, the full width
half maximum variation provides complementary constraints. These results can be
used to constrain blend scenarios for transiting planet candidates or radial
velocity planets. We review all the spectroscopic diagnoses reported in the
literature so far, especially the ones to monitor the line asymmetry. We
estimate their uncertainty and compare their sensitivity to blends. Based on
that, we recommend the use of BiGauss which is the most sensitive diagnosis to
monitor line-profile asymmetry. In this paper, we also investigate the
sensitivity of the radial velocities to constrain blend scenarios and develop a
formalism to estimate the level of dilution of a blended signal. Finally, we
apply our blend model to re-analyse the spectroscopic diagnoses of HD16702, an
unresolved face-on binary which exhibits bisector variations.Comment: Accepted for publication in MNRA
Novel Single Photon Detectors for UV Imaging
There are several applications which require high position resolution UV
imaging. For these applications we have developed and successfully tested a new
version of a 2D UV single photon imaging detector based on a microgap RPC. The
main features of such a detectors is the high position resolution - 30 micron
in digital form and the high quantum efficiency (1-8% in the spectral interval
of 220-140 nm). Additionally, they are spark- protected and can operate without
any feedback problems at high gains, close to a streamer mode. In attempts to
extend the sensitivity of RPCs to longer wavelengths we have successfully
tested the operation of the first sealed parallel-plate gaseous detectors with
CsTe photocathodes. Finally, the comparison with other types of photosensitive
detectors is given and possible fields of applications are identified.Comment: Presented at the 5th International Workshop on RICH detectors Playa
del Carmen, Mexico, November 200
The Energy Level Shifts, Wave Functions and the Probability Current Distributions for the Bound Scalar and Spinor Particles Moving in a Uniform Magnetic Field
We discuss the equations for the bound one-active electron states based on
the analytic solutions of the Schrodinger and Pauli equations for a uniform
magnetic field and a single attractive -potential. It is vary
important that ground electron states in the magnetic field differ essentially
from the analogous state of spin-0 particles, whose binding energy was
intensively studied more than forty years ago. We show that binding energy
equations for spin-1/2 particles can be obtained without using the language of
boundary conditions in the -potential model developed in pioneering
works. We use the obtained equations to calculate the energy level
displacements analytically and demonstrate nonlinear dependencies on field
intensity. We show that the magnetic field indeed plays a stabilizing role in
considered systems in a case of the weak intensity, but the opposite occurs in
the case of strong intensity. These properties may be important for real
quantum mechanical fermionic systems in two and three dimensions. We also
analyze the exact solution of the Pauli equation for an electron moving in the
potential field determined by the three-dimensional -well in the
presence of a strong magnetic field. We obtain asymptotic expressions for this
solution for different values of the problem parameters. In addition, we
consider electron probability currents and their dependence on the magnetic
field. We show that including the spin in the framework of the nonrelativistic
approach allows correctly taking the effect of the magnetic field on the
electric current into account. The obtained dependencies of the current
distribution, which is an experimentally observable quantity, can be manifested
directly in scattering processes, for example.Comment: 31 pages, 10 figure
Estimating the Dark Halo Mass from the Relative Thickness of Stellar Disks
We analyze the relationship between the mass of a spherical component and the
minimum possible thickness of stable stellar disks. This relationship for real
galaxies allows the lower limit on the dark halo mass to be estimated (the
thinner the stable stellar disk is, the more massive the dark halo must be). In
our analysis, we use both theoretical relations and numerical N-body
simulations of the dynamical evolution of thin disks in the presence of
spherical components with different density profiles and different masses. We
conclude that the theoretical relationship between the thickness of disk
galaxies and the mass of their spherical components is a lower envelope for the
model data points. We recommend using this theoretical relationship to estimate
the lower limit for the dark halo mass in galaxies. The estimate obtained turns
out to be weak. Even for the thinnest galaxies, the dark halo mass within four
exponential disk scale lengths must be more than one stellar disk mass.Comment: 20 pages including 6 figures. To be published in Astronomy Letters
(v. 32, No. 10, pp. 649-660, 2006
Out-of-Equilibrium Admittance of Single Electron Box Under Strong Coulomb Blockade
We study admittance and energy dissipation in an out-of-equlibrium single
electron box. The system consists of a small metallic island coupled to a
massive reservoir via single tunneling junction. The potential of electrons in
the island is controlled by an additional gate electrode. The energy
dissipation is caused by an AC gate voltage. The case of a strong Coulomb
blockade is considered. We focus on the regime when electron coherence can be
neglected but quantum fluctuations of charge are strong due to Coulomb
interaction. We obtain the admittance under the specified conditions. It turns
out that the energy dissipation rate can be expressed via charge relaxation
resistance and renormalized gate capacitance even out of equilibrium. We
suggest the admittance as a tool for a measurement of the bosonic distribution
corresponding collective excitations in the system
- âŠ