EEG–fMRI of idiopathic and secondarily generalized epilepsies

We used simultaneous EEG and functional MRI (EEG–fMRI) to study generalized spike wave activity (GSW) in idiopathic and secondary generalized epilepsy (SGE). Recent studies have demonstrated thalamic and cortical fMRI signal changes in association with GSW in idiopathic generalized epilepsy (IGE). We report on a large cohort of patients that included both IGE and SGE, and give a functional interpretation of our findings. Forty-six patients with GSW were studied with EEG–fMRI; 30 with IGE and 16 with SGE. GSW-related BOLD signal changes were seen in 25 of 36 individual patients who had GSW during EEG–fMRI. This was seen in thalamus (60%) and symmetrically in frontal cortex (92%), parietal cortex (76%), and posterior cingulate cortex/precuneus (80%). Thalamic BOLD changes were predominantly positive and cortical changes predominantly negative. Group analysis showed a negative BOLD response in the cortex in the IGE group and to a lesser extent a positive response in thalamus. Thalamic activation was consistent with its known role in GSW, and its detection in individual cases with EEG–fMRI may in part be related to the number and duration of GSW epochs recorded. The spatial distribution of the cortical fMRI response to GSW in both IGE and SGE involved areas of association cortex that are most active during conscious rest. Reduction of activity in these regions during GSW is consistent with the clinical manifestation of absence seizures

Development of a Reference Wafer for On-Wafer Testing of Extreme Impedance Devices

This paper describes the design, fabrication, and testing of an on-wafer substrate that has been developed specifically for measuring extreme impedance devices using an on-wafer probe station. Such devices include carbon nano-tubes (CNTs) and structures based on graphene which possess impedances in the κ Ω range and are generally realised on the nano-scale rather than the micro-scale that is used for conventional on-wafer measurement. These impedances are far removed from the conventional 50- reference impedance of the test equipment. The on-wafer substrate includes methods for transforming from the micro-scale towards the nano-scale and reference standards to enable calibrations for extreme impedance devices. The paper includes typical results obtained from the designed wafer

Walking in Sync: Two is Company, Three's a Crowd.

Eventual gait synchronization between two individuals while walking and talking with each other has been shown to be an indicator of agreeableness and companionship. The inferred physical signal from this subconscious phenomenon can po-tentially be an indicator of cooperation or relation between two individuals. In this paper we investigate this effect, and whether having a third person actively engaging in the same act or conversation can reduce this synchronization level. Using high frequency accelerometer data from a ded-icated smartphone app, we perform a number of controlled experiments on a number of individuals in different group configuration. Our results bring an interesting insight: it is the non-verbal social signals such as the gaze, head orienta-tion and gestures that is the key factor in synchronization, not necessarily the number or configuration of the walkers. These early results can lead us on detecting relationships between individuals or detecting the group formation and numbers for crowd-sensing applications when only partial data is available. Categories and Subject Descriptors Human-centered computing [Ubiquitous and mobile com-puting]: Empirical studies in ubiquitous and mobile com-putin

Feeding habits of sturgeon fishes in shallow coastal waters of Guilan Province, southern Caspian Sea

We collected sturgeon specimens from seven fishing stations operating 30 to 35 Km away from each other in Guilan province over the years 1999 MD 2000. Trawl nets six meters long were drawn using motorboats at each station, repeated three times for each season. Among the studied premature sturgeons, 121 Acipenser persicus specimens with an average age of less than two years and a length of 10 to 49.9 ± 0.77 cm showed full stomachs (57.17 % fullness). Among the mature specimens with an average age of 11 years and a length range of 90 to 194 cm, only three showed full stomachs (11.54 % fullness). The highest gut index in this study belonged to premature A. persicus. A one-way analysis of variance showed no significant difference in condition factor and gastro-somatic index among the different length groups (P<0.05). We found that the food consumed by premature A. persicus was comprised of eight genera of benthic invertebrates Hypania sp., Hypaniola sp., Pterocuma sp., Stenocuma sp., Abra ovata, Paramysis sp., Gammarus sp. and Nereis sp. Adult sturgeons were found feeding mainly on fish species belonging to Gobidae, Atherinidae and Clupeidae families. The main preys of premature A. persicus were polychaet worms Hypania sp. and Hypaniola sp. belonging to the class Sedantaria. Crustaceans Stenocuma sp. and Pterocuma sp. of the class Cumacea were also seen in the diet of the premature sturgeons. The main preys of adult A. persicus were fishes belonging to the family Gobiidae and secondary prey were fishes of the family Atherinidae

RF wafer probing with improved contact repeatability using nanometer positioning

International audienceThis paper presents an improved technique for monitoring and controlling the contact condition of on-wafer RF probes with nanometer accuracy to enhance the measurement repeatability. The set-up consists of a vector network analyzer, a modified probe station with a planar calibration substrate aligned under microwave GSG probe through a closed-loop nanopositioner and a camera system. A fully one-port SOL calibration is performed in the frequency range 0.05-50 GHz. A repeatability study based on standard deviations of the measured data considering both conventional and proposed approaches is described. From these experimental results, the improvement of the technique proposed is achieved by accurately controlling the probe contacts

Parameterization Models for Traceable Characterization of Planar CPW SOL Calibration Standards

International audienceMethods for traceable characterization and uncertainty evaluation of planar 1-port CPW short-open-load (SOL) devices are developed. The agreement of modelling and verification measurement results greatly supports the application of the proposed parameterization models and used FEM-based EM modelling of CPW structures for traceable characterization of planar CPW-based SOL devices in the frequency range between a few kHz up to 50 GHz

Multiport Vector Network Analyzer Configured in RF Interferometric Mode for Reference Impedance Renormalization

International audienceA novel active microwave interferometric technique is implemented on a multiport vector network analyzer for renormalizing the reference impedance 50 Ohms into any desired complex impedance. The resulting measured reflection coefficient around the new reference impedance is around zero, resulting in high measurement sensitivity. The method proposed avoids any external component commonly found in interferometric setups. In addition, a zeroing process including vector calibration is developed for broad frequency range and requires only a software procedure to be implemented in the system framework