1,138 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
Atmospheric number size distributions of soot particles and estimation of emission factors
International audienceNumber fractions of externally mixed particles of four different sizes (30, 50, 80, and 150 nm in diameter) were measured using a Volatility Tandem DMA. The system was operated in a street canyon (Eisenbahnstrasse, EI) and at an urban background site (Institute for Tropospheric Research, IfT), both in the city of Leipzig, Germany as well as at a rural site (Melpitz (ME), a village near Leipzig). Intensive campaigns of 3?5 weeks each took place in summer 2003 as well as in winter 2003/2004. The data set thus obtained provides mean number fractions of externally mixed soot particles of atmospheric aerosols in differently polluted areas and different seasons (e.g. at 80 nm on working days, 60% (EI), 22% (IfT), and 6% (ME) in summer and 26% (IfT), and 13% (ME) in winter). Furthermore, a new method is used to calculate the size distribution of these externally mixed soot particles from parallel number size distribution measurements. A decrease of the externally mixed soot fraction with decreasing urbanity and a diurnal variation linked to the daily traffic changes demonstrate, that the traffic emissions have a significant impact on the soot fraction in urban areas. This influence becomes less in rural areas, due to atmospheric mixing and transformation processes. For estimating the source strength of soot particles emitted by vehicles (veh), soot particle emission factors were calculated using the Operational Street Pollution Model (OSPM). The emission factor for an average vehicle was found to be (1.5±0.4)·1014 #/(km·veh). The separation of the emission factor into passenger cars ((5.8±2)·1013 #/(km·veh)) and trucks ((2.5±0.9)·1015 #/(km·veh)) yielded in a 40-times higher emission factor for trucks compared to passenger cars
Preoperative language mapping using navigated TMS compared with extra-operative direct cortical stimulation using intracranial electrodes: A case report
Highlights
1. rTMS provides a non-invasive means of performing pre-operative language mapping.
2. Sensitivity and specificity in epilepsy patients is lower than reported in tumour surgery.
3. Future methodological improvements may improve this
Coherent Control for a Two-level System Coupled to Phonons
The interband polarizations induced by two phase-locked pulses in a
semiconductor show strong interference effects depending on the time tau_1
separating the pulses. The four-wave mixing signal diffracted from a third
pulse delayed by tau is coherently controlled by tuning tau_1. The four-wave
mixing response is evaluated exactly for a two-level system coupled to a single
LO phonon. In the weak coupling regime it shows oscillations with the phonon
frequency which turn into sharp peaks at multiples of the phonon period for a
larger coupling strength. Destructive interferences between the two
phase-locked pulses produce a splitting of the phonon peaks into a doublet. For
fixed tau but varying tau_1 the signal shows rapid oscillations at the
interband-transition frequency, whose amplitude exhibits bursts at multiples of
the phonon period.Comment: 4 pages, 4 figures, RevTex, content change
Visual and semiautomated evaluation of epileptogenicity in focal cortical dysplasias - An intracranial EEG study
INTRODUCTION: The aim of the study was the evaluation of the added value of depth to subdural electrodes in delineating epileptogenicity of focal cortical dysplasias (FCDs) and to test the Epileptogenicity Index (EI) in this setting. MATERIAL AND METHODS: Fifteen patients with FCD underwent iEEG with subdural and depth electrodes. Visual/EI analysis was performed in up to three habitual seizures per patient. RESULTS: Visual analysis: Grid onset seizures (n=10) started in electrodes overlying the lesion in 7 and remote from it in 3 cases. Depth onset seizures (n=7) affected only intralesional contacts in 4, intra- and extralesional in 2, and exclusively extralesional in 1 patient. Seizures started in depth and grid contacts simultaneously in 2 cases. EI analysis: The EI completely confirmed visual localization of seizure onset in 8 cases and depicted ictal onset-time accurately in 13. Beta/gamma ictal patterns were most reliably captured. Impact on surgical decision: Resection outline differed from MRI lesion in 7 patients based on grid and in three based on depth electrode information. DISCUSSION: In FCD, seizures can be generated within gyral/deep tissue appearing normal on imaging. CONCLUSION: Investigating FCD with subdural and depth electrodes is efficient to outline the seizure onset zone. The EI is a helpful additional tool to quantify epileptogenicity. Specific ictal patterns are prerequisite for reliable results
Feasibility of multimodal 3D neuroimaging to guide implantation of intracranial EEG electrodes
Since intracranial electrode implantation has limited spatial sampling and carries significant risk, placement has to be effective and efficient. Structural and functional imaging of several different modalities contributes to localising the seizure onset zone (SoZ) and eloquent cortex. There is a need to summarise and present this information throughout the pre/intra/post-surgical course
La controvertida nacionalidad de Ricardo Maduro Joest, candidato a la Presidencia de la República de Honduras.
Con independencia de una eventual aplicación retroactiva de los preceptos sobre nacionalidad de la vigente Constitución hondureña, el relato fáctico puesto en relación con los sucesivos cambios legislativos acaecidos en Honduras y con la incorporación a Convenios internacionales de este país, es totalmente favorable a la consideración de que Ricardo Maduro Joest posee la nacionalidad hondureña por nacimiento y que junto a otras circunstancias personales que en él concurren esta en plenitud, por ende, de los derechos de ciudadanía que tal modalidad de nacionalidad confiere
Conclusive quantum steering with superconducting transition edge sensors
Quantum steering allows two parties to verify shared entanglement even if one
measurement device is untrusted. A conclusive demonstration of steering through
the violation of a steering inequality is of considerable fundamental interest
and opens up applications in quantum communication. To date all experimental
tests with single photon states have relied on post-selection, allowing
untrusted devices to cheat by hiding unfavourable events in losses. Here we
close this "detection loophole" by combining a highly efficient source of
entangled photon pairs with superconducting transition edge sensors. We achieve
an unprecedented ~62% conditional detection efficiency of entangled photons and
violate a steering inequality with the minimal number of measurement settings
by 48 standard deviations. Our results provide a clear path to practical
applications of steering and to a photonic loophole-free Bell test.Comment: Preprint of 7 pages, 3 figures; the definitive version is published
in Nature Communications, see below. Also, see related experimental work by
A. J. Bennet et al., arXiv:1111.0739 and B. Wittmann et al., arXiv:1111.076
Entropy in general physical theories
Information plays an important role in our understanding of the physical
world. We hence propose an entropic measure of information for any physical
theory that admits systems, states and measurements. In the quantum and
classical world, our measure reduces to the von Neumann and Shannon entropy
respectively. It can even be used in a quantum or classical setting where we
are only allowed to perform a limited set of operations. In a world that admits
superstrong correlations in the form of non-local boxes, our measure can be
used to analyze protocols such as superstrong random access encodings and the
violation of `information causality'. However, we also show that in such a
world no entropic measure can exhibit all properties we commonly accept in a
quantum setting. For example, there exists no`reasonable' measure of
conditional entropy that is subadditive. Finally, we prove a coding theorem for
some theories that is analogous to the quantum and classical setting, providing
us with an appealing operational interpretation.Comment: 20 pages, revtex, 7 figures, v2: Coding theorem revised, published
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