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Sample records for assimilating seizure dynamics

  1. Assimilating seizure dynamics.

    Science.gov (United States)

    Ullah, Ghanim; Schiff, Steven J

    2010-05-01

    Observability of a dynamical system requires an understanding of its state-the collective values of its variables. However, existing techniques are too limited to measure all but a small fraction of the physical variables and parameters of neuronal networks. We constructed models of the biophysical properties of neuronal membrane, synaptic, and microenvironment dynamics, and incorporated them into a model-based predictor-controller framework from modern control theory. We demonstrate that it is now possible to meaningfully estimate the dynamics of small neuronal networks using as few as a single measured variable. Specifically, we assimilate noisy membrane potential measurements from individual hippocampal neurons to reconstruct the dynamics of networks of these cells, their extracellular microenvironment, and the activities of different neuronal types during seizures. We use reconstruction to account for unmeasured parts of the neuronal system, relating micro-domain metabolic processes to cellular excitability, and validate the reconstruction of cellular dynamical interactions against actual measurements. Data assimilation, the fusing of measurement with computational models, has significant potential to improve the way we observe and understand brain dynamics. PMID:20463875

  2. Assimilating seizure dynamics.

    Directory of Open Access Journals (Sweden)

    Ghanim Ullah

    2010-05-01

    Full Text Available Observability of a dynamical system requires an understanding of its state-the collective values of its variables. However, existing techniques are too limited to measure all but a small fraction of the physical variables and parameters of neuronal networks. We constructed models of the biophysical properties of neuronal membrane, synaptic, and microenvironment dynamics, and incorporated them into a model-based predictor-controller framework from modern control theory. We demonstrate that it is now possible to meaningfully estimate the dynamics of small neuronal networks using as few as a single measured variable. Specifically, we assimilate noisy membrane potential measurements from individual hippocampal neurons to reconstruct the dynamics of networks of these cells, their extracellular microenvironment, and the activities of different neuronal types during seizures. We use reconstruction to account for unmeasured parts of the neuronal system, relating micro-domain metabolic processes to cellular excitability, and validate the reconstruction of cellular dynamical interactions against actual measurements. Data assimilation, the fusing of measurement with computational models, has significant potential to improve the way we observe and understand brain dynamics.

  3. Assimilation Dynamic Network (ADN) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Assimilation Dynamic Network (ADN) is a dynamic inter-processor communication network that spans heterogeneous processor architectures, unifying components,...

  4. [Seizure].

    Science.gov (United States)

    Saito, Ayumi; Terayama, Yasuo

    2013-06-01

    Seizure is defined as "a strong shrinkage state of the skeletal muscle which is involuntary, and occurs spasmodically" and it is often accompanied by disturbance of consciousness. The typical disease which causes seizure is epilepsy. But there is many conditions causing seizure. Therefore, diagnosis of epilepsy should be careful. Seizure among eldery increases in an era of an aging population in Japan. The risk of recurrence of seizure or epilepsy in elderly is higher than that in youth. In considering of the treatment of seizure among elderly, differential diagnosis from various condition must be done. PMID:23855204

  5. Seizures

    Science.gov (United States)

    ... After a seizure — particularly if it is a first or unexplained seizure — call your doctor or emergency medical services for instructions. Your child will usually need to be seen by a doctor as soon as possible. Reviewed by: Rupal Christine Gupta, MD Date reviewed: June ... ON THIS TOPIC Breath-Holding Spells First Aid: Seizures First Aid: Fainting First Aid: Febrile ...

  6. NEURONAL AND NETWORK DYNAMICS PRECEDING EXPERIMENTAL SEIZURES

    Czech Academy of Sciences Publication Activity Database

    Jiruška, Přemysl; Mormann, F.; Jefferys, J. G. R.

    Singapore : World Scientific Publ, 2013 - (Tetzlaff, R.; Elger, C.; Lehnertz, K.), s. 16-29 ISBN 978-981-4525-35-0. [International Workshop on Seizure Prediction /5./. Dresden (DE), 18.09.2011-23.09.2011] Institutional research plan: CEZ:AV0Z50110509 Institutional support: RVO:67985823 Keywords : seizure prediction * epilepsy * critical transition Subject RIV: FH - Neurology

  7. Plasticity-modulated seizure dynamics for seizure termination in realistic neuronal models

    Science.gov (United States)

    Koppert, M. M. J.; Kalitzin, S.; Lopes da Silva, F. H.; Viergever, M. A.

    2011-08-01

    In previous studies we showed that autonomous absence seizure generation and termination can be explained by realistic neuronal models eliciting bi-stable dynamics. In these models epileptic seizures are triggered either by external stimuli (reflex epilepsies) or by internal fluctuations. This scenario predicts exponential distributions of the duration of the seizures and of the inter-ictal intervals. These predictions were validated in rat models of absence epilepsy, as well as in a few human cases. Nonetheless, deviations from the predictions with respect to seizure duration distributions remained unexplained. The objective of the present work is to implement a simple but realistic computational model of a neuronal network including synaptic plasticity and ionic current dynamics and to explore the dynamics of the model with special emphasis on the distributions of seizure and inter-ictal period durations. We use as a basis our lumped model of cortical neuronal circuits. Here we introduce 'activity dependent' parameters, namely post-synaptic voltage-dependent plasticity, as well as a voltage-dependent hyperpolarization-activated current driven by slow and fast activation conductances. We examine the distributions of the durations of the seizure-like model activity and the normal activity, described respectively by the limit cycle and the steady state in the dynamics. We use a parametric γ-distribution fit as a quantifier. Our results show that autonomous, activity-dependent membrane processes can account for experimentally obtained statistical distributions of seizure durations, which were not explainable using the previous model. The activity-dependent membrane processes that display the strongest effect in accounting for these distributions are the hyperpolarization-dependent cationic (Ih) current and the GABAa plastic dynamics. Plastic synapses (NMDA-type) in the interneuron population show only a minor effect. The inter-ictal statistics retain their

  8. Optogenetically induced seizure and the longitudinal hippocampal network dynamics.

    Directory of Open Access Journals (Sweden)

    Shin-Ichiro Osawa

    Full Text Available Epileptic seizure is a paroxysmal and self-limited phenomenon characterized by abnormal hypersynchrony of a large population of neurons. However, our current understanding of seizure dynamics is still limited. Here we propose a novel in vivo model of seizure-like afterdischarges using optogenetics, and report on investigation of directional network dynamics during seizure along the septo-temporal (ST axis of hippocampus. Repetitive pulse photostimulation was applied to the rodent hippocampus, in which channelrhodopsin-2 (ChR2 was expressed, under simultaneous recording of local field potentials (LFPs. Seizure-like afterdischarges were successfully induced after the stimulation in both W-TChR2V4 transgenic (ChR2V-TG rats and in wild type rats transfected with adeno-associated virus (AAV vectors carrying ChR2. Pulse frequency at 10 and 20 Hz, and a 0.05 duty ratio were optimal for afterdischarge induction. Immunohistochemical c-Fos staining after a single induced afterdischarge confirmed neuronal activation of the entire hippocampus. LFPs were recorded during seizure-like afterdischarges with a multi-contact array electrode inserted along the ST axis of hippocampus. Granger causality analysis of the LFPs showed a bidirectional but asymmetric increase in signal flow along the ST direction. State space presentation of the causality and coherence revealed three discrete states of the seizure-like afterdischarge phenomenon: 1 resting state; 2 afterdischarge initiation with moderate coherence and dominant septal-to-temporal causality; and 3 afterdischarge termination with increased coherence and dominant temporal-to-septal causality. A novel in vivo model of seizure-like afterdischarge was developed using optogenetics, which was advantageous in its reproducibility and artifact-free electrophysiological observations. Our results provide additional evidence for the potential role of hippocampal septo-temporal interactions in seizure dynamics in vivo

  9. A novel dynamic update framework for epileptic seizure prediction.

    Science.gov (United States)

    Han, Min; Ge, Sunan; Wang, Minghui; Hong, Xiaojun; Han, Jie

    2014-01-01

    Epileptic seizure prediction is a difficult problem in clinical applications, and it has the potential to significantly improve the patients' daily lives whose seizures cannot be controlled by either drugs or surgery. However, most current studies of epileptic seizure prediction focus on high sensitivity and low false-positive rate only and lack the flexibility for a variety of epileptic seizures and patients' physical conditions. Therefore, a novel dynamic update framework for epileptic seizure prediction is proposed in this paper. In this framework, two basic sample pools are constructed and updated dynamically. Furthermore, the prediction model can be updated to be the most appropriate one for the prediction of seizures' arrival. Mahalanobis distance is introduced in this part to solve the problem of side information, measuring the distance between two data sets. In addition, a multichannel feature extraction method based on Hilbert-Huang transform and extreme learning machine is utilized to extract the features of a patient's preseizure state against the normal state. At last, a dynamic update epileptic seizure prediction system is built up. Simulations on Freiburg database show that the proposed system has a better performance than the one without update. The research of this paper is significantly helpful for clinical applications, especially for the exploitation of online portable devices. PMID:25050381

  10. A Novel Dynamic Update Framework for Epileptic Seizure Prediction

    Directory of Open Access Journals (Sweden)

    Min Han

    2014-01-01

    Full Text Available Epileptic seizure prediction is a difficult problem in clinical applications, and it has the potential to significantly improve the patients’ daily lives whose seizures cannot be controlled by either drugs or surgery. However, most current studies of epileptic seizure prediction focus on high sensitivity and low false-positive rate only and lack the flexibility for a variety of epileptic seizures and patients’ physical conditions. Therefore, a novel dynamic update framework for epileptic seizure prediction is proposed in this paper. In this framework, two basic sample pools are constructed and updated dynamically. Furthermore, the prediction model can be updated to be the most appropriate one for the prediction of seizures’ arrival. Mahalanobis distance is introduced in this part to solve the problem of side information, measuring the distance between two data sets. In addition, a multichannel feature extraction method based on Hilbert-Huang transform and extreme learning machine is utilized to extract the features of a patient’s preseizure state against the normal state. At last, a dynamic update epileptic seizure prediction system is built up. Simulations on Freiburg database show that the proposed system has a better performance than the one without update. The research of this paper is significantly helpful for clinical applications, especially for the exploitation of online portable devices.

  11. Dynamics of muscle activation during tonic-clonic seizures

    DEFF Research Database (Denmark)

    Conradsen, Isa; Moldovan, Mihai; Jennum, Poul;

    2013-01-01

    The purpose of our study was to elucidate the dynamics of muscle activation during generalised tonic-clonic seizures (GTCS). We recorded surface electromyography (EMG) from the deltoid muscle during 26 GTCS from 13 patients and compared it with GTCS-like events acted by 10 control subjects. GTCS...... consisted of a sequence of phases best described quantitatively by dynamics of the low frequency (LF) wavelet component (2-8Hz). Contrary to the traditional view, the tonic phase started with a gradual increase in muscle activity. A longer clonic phase was associated with a shorter onset of the tonic phase......) of exponentially increasing duration - features that could not be reproduced voluntarily. The last SP was longer in seizures with higher EMG peak frequency whereas the energy of the last clonus was higher in seizures with a short clonic phase. We found specific features of muscle activation dynamics...

  12. The dynamic radiation environment assimilation model (DREAM)

    International Nuclear Information System (INIS)

    The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate results than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.

  13. The dynamic radiation environment assimilation model (DREAM)

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Geoffrey D [Los Alamos National Laboratory; Koller, Josef [Los Alamos National Laboratory; Tokar, Robert L [Los Alamos National Laboratory; Chen, Yue [Los Alamos National Laboratory; Henderson, Michael G [Los Alamos National Laboratory; Friedel, Reiner H [Los Alamos National Laboratory

    2010-01-01

    The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate results than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.

  14. Assimilating uncertain, dynamic and intermittent streamflow observations in hydrological models

    Science.gov (United States)

    Mazzoleni, Maurizio; Alfonso, Leonardo; Chacon-Hurtado, Juan; Solomatine, Dimitri

    2015-09-01

    Catastrophic floods cause significant socio-economical losses. Non-structural measures, such as real-time flood forecasting, can potentially reduce flood risk. To this end, data assimilation methods have been used to improve flood forecasts by integrating static ground observations, and in some cases also remote sensing observations, within water models. Current hydrologic and hydraulic research works consider assimilation of observations coming from traditional, static sensors. At the same time, low-cost, mobile sensors and mobile communication devices are becoming also increasingly available. The main goal and innovation of this study is to demonstrate the usefulness of assimilating uncertain streamflow observations that are dynamic in space and intermittent in time in the context of two different semi-distributed hydrological model structures. The developed method is applied to the Brue basin, where the dynamic observations are imitated by the synthetic observations of discharge. The results of this study show how model structures and sensors locations affect in different ways the assimilation of streamflow observations. In addition, it proves how assimilation of such uncertain observations from dynamic sensors can provide model improvements similar to those of streamflow observations coming from a non-optimal network of static physical sensors. This can be a potential application of recent efforts to build citizen observatories of water, which can make the citizens an active part in information capturing, evaluation and communication, helping simultaneously to improvement of model-based flood forecasting.

  15. Dynamical analogy between epileptic seizures and seismogenic electromagnetic emissions by means of nonextensive statistical mechanics

    CERN Document Server

    Eftaxias, Konstantinos; Potirakis, Stelios M; Balasis, George

    2012-01-01

    The field of study of complex systems considers that the dynamics of complex systems are founded on universal principles that may be used to describe a great variety of scientific and technological approaches of different types of natural, artificial, and social systems. Several authors have suggested that earthquake dynamics and neurodynamics can be analyzed within similar mathematical frameworks. Recently, authors have shown that a dynamical analogy supported by scale-free statistics exists between seizures and earthquakes, analysing populations of different seizures and earthquakes, respectively. The purpose of this paper is to suggest a shift in emphasis from the large to the small scale: our analyses focus on a single epileptic seizure generation and the activation of a single fault (earthquake) and not on the statistics of sequences of different seizures and earthquakes. We apply the concepts of the nonextensive statistical physics to support the suggestion that a dynamical analogy exists between the tw...

  16. Interaction between synaptic inhibition and glial-potassium dynamics leads to diverse seizure transition modes in biophysical models of human focal seizures.

    Science.gov (United States)

    Y Ho, E C; Truccolo, Wilson

    2016-10-01

    How focal seizures initiate and evolve in human neocortex remains a fundamental problem in neuroscience. Here, we use biophysical neuronal network models of neocortical patches to study how the interaction between inhibition and extracellular potassium ([K (+)] o ) dynamics may contribute to different types of focal seizures. Three main types of propagated focal seizures observed in recent intracortical microelectrode recordings in humans were modelled: seizures characterized by sustained (∼30-60 Hz) gamma local field potential (LFP) oscillations; seizures where the onset in the propagated site consisted of LFP spikes that later evolved into rhythmic (∼2-3 Hz) spike-wave complexes (SWCs); and seizures where a brief stage of low-amplitude fast-oscillation (∼10-20 Hz) LFPs preceded the SWC activity. Our findings are fourfold: (1) The interaction between elevated [K (+)] o (due to abnormal potassium buffering by glial cells) and the strength of synaptic inhibition plays a predominant role in shaping these three types of seizures. (2) Strengthening of inhibition leads to the onset of sustained narrowband gamma seizures. (3) Transition into SWC seizures is obtained either by the weakening of inhibitory synapses, or by a transient strengthening followed by an inhibitory breakdown (e.g. GABA depletion). This reduction or breakdown of inhibition among fast-spiking (FS) inhibitory interneurons increases their spiking activity and leads them eventually into depolarization block. Ictal spike-wave discharges in the model are then sustained solely by pyramidal neurons. (4) FS cell dynamics are also critical for seizures where the evolution into SWC activity is preceded by low-amplitude fast oscillations. Different levels of elevated [K (+)] o were important for transitions into and maintenance of sustained gamma oscillations and SWC discharges. Overall, our modelling study predicts that the interaction between inhibitory interneurons and [K (+)] o glial buffering under

  17. Application of statistical dynamical turbulence closures to data assimilation

    International Nuclear Information System (INIS)

    We describe the development of an accurate yet computationally tractable statistical dynamical closure theory for general inhomogeneous turbulent flows, coined the quasi-diagonal direct interaction approximation closure (QDIA), and its application to problems in data assimilation. The QDIA provides prognostic equations for evolving mean fields, covariances and higher-order non-Gaussian terms, all of which are also required in the formulation of data assimilation schemes for nonlinear geophysical flows. The QDIA is a generalization of the class of direct interaction approximation theories, initially developed by Kraichnan (1959 J. Fluid Mech. 5 497) for isotropic turbulence, to fully inhomogeneous flows and has been further generalized to allow for both inhomogeneous and non-Gaussian initial conditions and long integrations. A regularization procedure or empirical vertex renormalization that ensures correct inertial range spectra is also described. The aim of this paper is to provide a coherent mathematical description of the QDIA turbulence closure and closure-based data assimilation scheme we have labeled the statistical dynamical Kalman filter. The mathematical formalism presented has been synthesized from recent works of the authors with some additional material and is presented in sufficient detail that the paper is of a pedagogical nature.

  18. Nonlinear error dynamics for cycled data assimilation methods

    International Nuclear Information System (INIS)

    We investigate the error dynamics for cycled data assimilation systems, such that the inverse problem of state determination is solved at tk, k = 1, 2, 3, …, with a first guess given by the state propagated via a dynamical system model Mk from time tk−1 to time tk. In particular, for nonlinear dynamical systems Mk that are Lipschitz continuous with respect to their initial states, we provide deterministic estimates for the development of the error ‖ek‖ ≔ ‖x(a)k − x(t)k‖ between the estimated state x(a) and the true state x(t) over time. Clearly, observation error of size δ > 0 leads to an estimation error in every assimilation step. These errors can accumulate, if they are not (a) controlled in the reconstruction and (b) damped by the dynamical system Mk under consideration. A data assimilation method is called stable, if the error in the estimate is bounded in time by some constant C. The key task of this work is to provide estimates for the error ‖ek‖, depending on the size δ of the observation error, the reconstruction operator Rα, the observation operator H and the Lipschitz constants K(1) and K(2) on the lower and higher modes of Mk controlling the damping behaviour of the dynamics. We show that systems can be stabilized by choosing α sufficiently small, but the bound C will then depend on the data error δ in the form c‖Rα‖δ with some constant c. Since ‖Rα‖ → ∞ for α → 0, the constant might be large. Numerical examples for this behaviour in the nonlinear case are provided using a (low-dimensional) Lorenz ‘63 system. (paper)

  19. Local driving and global interactions in the progression of seizure dynamics

    CERN Document Server

    Singer, B H; Carlen, P L; Zochowski, M; Singer, Benjamin H.; Derchansky, Miron; Carlen, Peter L.; Zochowski, Michal

    2005-01-01

    The dynamics underlying epileptic seizures are well understood. We present a novel analysis of seizure-like events (SLEs) in an \\textit{ex vivo} whole hippocampus, as well as a modeling study that sheds light on the underlying network dynamics. We show that every SLE can be divided into two phases. During the first, SLE dynamics are driven by the intra-network interaction of a network exhibiting high internal synchrony. The second phase is characterized by lead switching, with the leading region exhibiting low internal synchrony. We show that the second phase dynamics are driven by inter-network feedback among multiple regions of the hippocampus.

  20. Data assimilation for xenon dynamics in nuclear plant

    International Nuclear Information System (INIS)

    Xenon-135 is a nuclear fission product which is known to be source of undesired roughly one day period density axial oscillations in pressurized water reactors. Xenon dynamics are non linearly coupled to another fission product the iodine-135. Such a coupling represents a challenge for the oscillation prediction. In order to improve xenon estimation, we investigate the feasibility of using variational data assimilation methods. The aim is to obtain a better estimation of initial 1D concentrations of xenon and iodine. Data assimilation techniques are widely used in meteorology and oceanography to improve initial states and forecasts. Such methods combine all kind of information about the system (model, a prior estimate of the true state and data). These information are weighted according to their accuracy expressed in error covariance matrices. The state resulting from the assimilation process is called analysis. 3DVAR and 4DVAR schemes for xenon dynamics are developed within the framework of twin experiments. This means that observations are obtained through numerical computation. Such a procedure allows an evaluation of produced analysis quality. The model developed for this purpose (CIREP1D) includes a mono-dimensional xenon dynamics linked to a mono-dimensional thermic and thermohydraulic model. Linear tangent and adjoint of this model are obtained through automatic differentiation. Observations are of three kinds: integrated powers over several nodes, power axial offset and boron concentration. This work figures out improvements on the estimation of iodine and xenon initial concentrations. Such encouraging results allow to set up tuning tool for an operator guiding system. (author)

  1. Preictal Dynamics of EEG Complexity in Intracranially Recorded Epileptic Seizure

    Czech Academy of Sciences Publication Activity Database

    Bob, P.; Roman, R.; Světlák, M.; Kukleta, M.; Chládek, Jan; Brázdil, M.

    2014-01-01

    Roč. 93, č. 23 (2014), el151:1-4. ISSN 0025-7974 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : EEG * epileptic Seizure Subject RIV: FS - Medical Facilities ; Equipment Impact factor: 5.723, year: 2014

  2. Application of approximate entropy on dynamic characteristics of epileptic absence seizure

    Institute of Scientific and Technical Information of China (English)

    Yi Zhou; Ruimei Huang; Ziyi Chen; Xin Chang; Jialong Chen; Lingli Xie

    2012-01-01

    Electroencephalogram signals are time-varying complex electrophysiological signals. Existing studies show that approximate entropy, which is a nonlinear dynamics index, is not an ideal method for electroencephalogram analysis. Clinical electroencephalogram measurements usually contain electrical interference signals, creating additional challenges in terms of maintaining robustness of the analytic methods. There is an urgent need for a novel method of nonlinear dynamical analysis of the electroencephalogram that can characterize seizure-related changes in cerebral dynamics. The aim of this paper was to study the fluctuations of approximate entropy in preictal, ictal, and postictal electroencephalogram signals from a patient with absence seizures, and to improve the algorithm used to calculate the approximate entropy. The approximate entropy algorithm, especially our modified version, could accurately describe the dynamical changes of the brain during absence seizures. We could also demonstrate that the complexity of the brain was greater in the normal state than in the ictal state. The fluctuations of the approximate entropy before epileptic seizures observed in this study can form a goodbasis for further study on the prediction of seizures with nonlinear dynamics.

  3. Dynamics of the employment assimilation of first-generation immigrant men in Sweden: comparing dynamic and static assimilation models with longitudinal data

    OpenAIRE

    Akay, Alpaslan

    2009-01-01

    We analyse the dynamics of employment assimilation of first-generation immigrant men in Sweden using a high-quality, register-based panel data set. It is discussed that when there are significant differences between employment status persistence of immigrants and natives, the standard static assimilation model produces biased predictions for the relative labour market outcomes for immigrants. We find significant persistence of employment status which differs between immigrants and natives, an...

  4. Information theoretic measures of network coordination in high-frequency scalp EEG reveal dynamic patterns associated with seizure termination.

    Science.gov (United States)

    Stamoulis, Catherine; Schomer, Donald L; Chang, Bernard S

    2013-08-01

    How a seizure terminates is still under-studied and, despite its clinical importance, remains an obscure phase of seizure evolution. Recent studies of seizure-related scalp EEGs at frequencies >100 Hz suggest that neural activity, in the form of oscillations and/or neuronal network interactions, may play an important role in preictal/ictal seizure evolution (Andrade-Valenca et al., 2011; Stamoulis et al., 2012). However, the role of high-frequency activity in seizure termination, is unknown, if it exists at all. Using information theoretic measures of network coordination, this study investigated ictal and immediate postictal neurodynamic interactions encoded in scalp EEGs from a relatively small sample of 8 patients with focal epilepsy and multiple seizures originating in temporal and/or frontal brain regions, at frequencies ≤ 100 Hz and >100 Hz, respectively. Despite some heterogeneity in the dynamics of these interactions, consistent patterns were also estimated. Specifically, in several seizures, linear or non-linear increase in high-frequency neuronal coordination during ictal intervals, coincided with a corresponding decrease in coordination at frequencies <100 Hz, suggesting a potential interference role of high-frequency activity, to disrupt abnormal ictal synchrony at lower frequencies. These changes in network synchrony started at least 20-30s prior to seizure offset, depending on the seizure duration. Opposite patterns were estimated at frequencies ≤ 100 Hz in several seizures. These results raise the possibility that high-frequency interference may occur in the form of progressive network coordination during the ictal interval, which continues during the postictal interval. This may be one of several possible mechanisms that facilitate seizure termination. In fact, inhibition of pairwise interactions between EEGs by other signals in their spatial neighborhood, quantified by negative interaction information, was estimated at frequencies ≤ 100 Hz

  5. Sequential assimilation of multi-mission dynamical topography into a global finite-element ocean model

    Directory of Open Access Journals (Sweden)

    S. Skachko

    2008-12-01

    Full Text Available This study focuses on an accurate estimation of ocean circulation via assimilation of satellite measurements of ocean dynamical topography into the global finite-element ocean model (FEOM. The dynamical topography data are derived from a complex analysis of multi-mission altimetry data combined with a referenced earth geoid. The assimilation is split into two parts. First, the mean dynamic topography is adjusted. To this end an adiabatic pressure correction method is used which reduces model divergence from the real evolution. Second, a sequential assimilation technique is applied to improve the representation of thermodynamical processes by assimilating the time varying dynamic topography. A method is used according to which the temperature and salinity are updated following the vertical structure of the first baroclinic mode. It is shown that the method leads to a partially successful assimilation approach reducing the rms difference between the model and data from 16 cm to 2 cm. This improvement of the mean state is accompanied by significant improvement of temporal variability in our analysis. However, it remains suboptimal, showing a tendency in the forecast phase of returning toward a free run without data assimilation. Both the mean difference and standard deviation of the difference between the forecast and observation data are reduced as the result of assimilation.

  6. Opinion Dynamics with Heterogeneous Interactions and Information Assimilation

    Science.gov (United States)

    Mir Tabatabaei, Seydeh Anahita

    2013-01-01

    In any modern society, individuals interact to form opinions on various topics, including economic, political, and social aspects. Opinions evolve as the result of the continuous exchange of information among individuals and of the assimilation of information distributed by media. The impact of individuals' opinions on each other forms a network,…

  7. Dynamic imaging of coherent sources reveals different network connectivity underlying the generation and perpetuation of epileptic seizures.

    Directory of Open Access Journals (Sweden)

    Lydia Elshoff

    Full Text Available The concept of focal epilepsies includes a seizure origin in brain regions with hyper synchronous activity (epileptogenic zone and seizure onset zone and a complex epileptic network of different brain areas involved in the generation, propagation, and modulation of seizures. The purpose of this work was to study functional and effective connectivity between regions involved in networks of epileptic seizures. The beginning and middle part of focal seizures from ictal surface EEG data were analyzed using dynamic imaging of coherent sources (DICS, an inverse solution in the frequency domain which describes neuronal networks and coherences of oscillatory brain activities. The information flow (effective connectivity between coherent sources was investigated using the renormalized partial directed coherence (RPDC method. In 8/11 patients, the first and second source of epileptic activity as found by DICS were concordant with the operative resection site; these patients became seizure free after epilepsy surgery. In the remaining 3 patients, the results of DICS / RPDC calculations and the resection site were discordant; these patients had a poorer post-operative outcome. The first sources as found by DICS were located predominantly in cortical structures; subsequent sources included some subcortical structures: thalamus, Nucl. Subthalamicus and cerebellum. DICS seems to be a powerful tool to define the seizure onset zone and the epileptic networks involved. Seizure generation seems to be related to the propagation of epileptic activity from the primary source in the seizure onset zone, and maintenance of seizures is attributed to the perpetuation of epileptic activity between nodes in the epileptic network. Despite of these promising results, this proof of principle study needs further confirmation prior to the use of the described methods in the clinical praxis.

  8. Assimilation of Thermodynamic and Dynamic Boundary Layer Profiler Data

    Science.gov (United States)

    Crowell, S.; Turner, D. D.; Otkin, J.

    2012-12-01

    In 2009, the National Research Council issued a report stating that a fundamental limitation to our understanding of mesoscale meteorological phenomena is the absence of adequate observations in the atmospheric boundary layer. In Otkin et al (2011) and Hartung et al (2011), an Observing Systems Simulation Experiment was described that concluded that the inclusion of thermodynamic retrievals from instruments like the Atmospheric Emitted Radiance Interferometer, together with wind observations from a Doppler lidar, could improve precipitation forecast skill scores using an ensemble Kalman filter (DART) together with the Weather Research and Forecasting Model (WRF). Here we discuss a second set of experiments in which the density of the proposed profiler network was doubled. Surprisingly, the results were only marginally better, and in some cases were degraded. This can be seen to be an effect of decreasing spread in the location of the strongest atmospheric gradients. An alternate set of experiments was performed with the 3D Variational framework, with the background error correlation length scales being tuned to match the EnKF localization as closely as possible. Interestingly, the 3DVar solutions exhibit qualitatively different responses to the assimilation of the observations than the EnKF solutions, with the placement and magnitude of the precipitation being improved, as determined by examining model precipitation on transects passing orthogonal to the front. A second case study will also be presented, in which we explore the relative importance of model error and observations for a springtime convective cased modeled on the May 24, 2011 tornado outbreak that passed through Texas, Oklahoma and Kansas. The sensitivity of convective processes to subgrid physics parameterizations can be seen to be a challenging problem for a data assimilation system, regardless of the quality of the observations being assimilated. Rather than using precipitation as the metric for

  9. Assimilation of geomagnetic observations in dynamical models of the secular variation

    International Nuclear Information System (INIS)

    Complete text of publication follows. Satellite data contribute to a better description of the secular variation of the main geomagnetic field. To make the best use of that (and upcoming) wealth of data, we consider the possibility to resort to data assimilation, as now routinely used in the fields of meteorology and oceanography. Geomagnetic data assimilation aims at identifying the physics of the Earth's core responsible for the secular variation recorded by satellites and in long-lived, ground observatories. Data assimilation should yield a more accurate forecast of the secular variation, and enable the reanalysis of historical observations. The physics at the heart of our assimilation scheme is based on the assumption that the dynamics responsible for the fast (i.e. interannual) variations of the main magnetic field is quasi-geostrophic. In addition, we describe similarly the magnetic field, in the core interior, using a magnetic flux function, whose dynamics is also two-dimensional. In this presentation, we will focus on the methodological aspects of our assimilation scheme. In particular, we illustrate how the accumulation of successive observations can be used to construct dynamically consistent, time-dependent maps of the magnetic field inside the core.

  10. A data assimilation tool for the Pagasitikos Gulf ecosystem dynamics: Methods and benefits

    KAUST Repository

    Korres, Gerasimos

    2012-06-01

    Within the framework of the European INSEA project, an advanced assimilation system has been implemented for the Pagasitikos Gulf ecosystem. The system is based on a multivariate sequential data assimilation scheme that combines satellite ocean sea color (chlorophyll-a) data with the predictions of a three-dimensional coupled physical-biochemical model of the Pagasitikos Gulf ecosystem presented in a companion paper. The hydrodynamics are solved with a very high resolution (1/100°) implementation of the Princeton Ocean Model (POM). This model is nested within a coarser resolution model of the Aegean Sea which is part of the Greek POSEIDON forecasting system. The forecast of the Aegean Sea model, itself nested and initialized from a Mediterranean implementation of POM, is also used to periodically re-initalize the Pagatisikos hydrodynamics model using variational initialization techniques. The ecosystem dynamics of Pagasitikos are tackled with a stand-alone implementation of the European Seas Ecosystem Model (ERSEM). The assimilation scheme is based on the Singular Evolutive Extended Kalman (SEEK) filter, in which the error statistics are parameterized by means of a suitable set of Empirical Orthogonal Functions (EOFs).The assimilation experiments were performed for year 2003 and additionally for a 9-month period over 2006 during which the physical model was forced with the POSEIDON-ETA 6-hour atmospheric fields. The assimilation system is validated by assessing the relevance of the system in fitting the data, the impact of the assimilation on non-observed biochemical processes and the overall quality of the forecasts. Assimilation of either GlobColour in 2003 or SeaWiFS in 2006 chlorophyll-a data enhances the identification of the ecological state of the Pagasitikos Gulf. Results, however, suggest that subsurface ecological observations are needed to improve the controllability of the ecosystem in the deep layers. © 2011 Elsevier B.V.

  11. Neural networks for emulation variational method for data assimilation in nonlinear dynamics

    International Nuclear Information System (INIS)

    Description of a physical phenomenon through differential equations has errors involved, since the mathematical model is always an approximation of reality. For an operational prediction system, one strategy to improve the prediction is to add some information from the real dynamics into mathematical model. This additional information consists of observations on the phenomenon. However, the observational data insertion should be done carefully, for avoiding a worse performance of the prediction. Technical data assimilation are tools to combine data from physical-mathematics model with observational data to obtain a better forecast. The goal of this work is to present the performance of the Neural Network Multilayer Perceptrons trained to emulate a Variational method in context of data assimilation. Techniques for data assimilation are applied for the Lorenz systems; which presents a strong nonlinearity and chaotic nature.

  12. Assimilative modeling of ionospheric dynamics for nowcasting of HF propagation channels in the presence of TIDs

    Science.gov (United States)

    Nickisch, L. J.; Fridman, Sergey; Hausman, Mark; Kraut, Shawn; Zunich, George

    2016-03-01

    The ionospheric data assimilation algorithm called GPS Ionospheric Inversion (GPSII; pronounced "gypsy") has been extended and employed to model the dynamic ionosphere, including medium-scale traveling ionospheric disturbances (MS-TIDs). MS-TIDs are characterized by periods of 10-30 min. GPSII can assimilate many forms of ionospheric-related data, including ionogram data and GPS L1/L2 beacon data. For this present effort, GPSII was extended to assimilate propagation time delay, integrated Doppler shift, and angle-of-arrival (AoA) measurements of HF transmissions from known reference points (KRPs). GPSII applies a regularization technique that constrains the solver to find the smoothest 3-D ionosphere model that still reproduces the input data to within their respective errors of measurement. A companion paper documents the development of the assimilation capability for KRPs. In this paper we show test results of the model's performance in reproducing measured AoA variations in the presence of medium-scale traveling ionospheric disturbances (MS-TIDs) using near vertical incidence skywave data collected at White Sands Missile Range by the Intelligence Advanced Research Projects Activity HFGeo Program Government team. We find that using three KRPs within approximately 50 km of reference/check/nonassimilated transmitters, we can reproduce the measured AoAs of the nonassimilated transmitters to within 1.9° with 90% confidence even in the presence of highly dynamic MS-TIDs.

  13. Epilepsy or seizures - discharge

    Science.gov (United States)

    Focal seizure - discharge; Jacksonian seizure - discharge; Seizure - partial (focal) - discharge; TLE - discharge; Seizure - temporal lobe - discharge; Seizure - tonic-clonic - discharge; Seizure - grand mal - discharge; Grand mal seizure - discharge; Seizure - generalized - discharge

  14. Continuous dynamic assimilation of the inner region data in hydrodynamics modelling: optimization approach

    Directory of Open Access Journals (Sweden)

    F. I. Pisnitchenko

    2008-11-01

    Full Text Available In meteorological and oceanological studies the classical approach for finding the numerical solution of the regional model consists in formulating and solving a Cauchy-Dirichlet problem. The boundary conditions are obtained by linear interpolation of coarse-grid data provided by a global model. Errors in boundary conditions due to interpolation may cause large deviations from the correct regional solution. The methods developed to reduce these errors deal with continuous dynamic assimilation of known global data available inside the regional domain. One of the approaches of this assimilation procedure performs a nudging of large-scale components of regional model solution to large-scale global data components by introducing relaxation forcing terms into the regional model equations. As a result, the obtained solution is not a valid numerical solution to the original regional model. Another approach is the use a four-dimensional variational data assimilation procedure which is free from the above-mentioned shortcoming. In this work we formulate the joint problem of finding the regional model solution and data assimilation as a PDE-constrained optimization problem. Three simple model examples (ODE Burgers equation, Rossby-Oboukhov equation, Korteweg-de Vries equation are considered in this paper. Numerical experiments indicate that the optimization approach can significantly improve the precision of the regional solution.

  15. Assimilation of geodetic dynamic ocean topography with ensemble based Kalman filter

    OpenAIRE

    Janjic Pfander, Tijana; A. Albertella; Schröter, Jens; R. Savcenko; Rummel, R.; Bosch, W.

    2012-01-01

    We use the geodetic method to obtain the dynamical ocean topography (DOT). This method combines the multi-mission-altimeter sea surface height and the GRACE/GOCE gravity field. Using the new global filtering approach, the spectral consistency of both fields is achieved by filtering the sea surface height and the geoid. The new global filtering approach reduces the artificats near the coast lines. Further, results of assimilation of multi-mission-altimeter data and the GRACE/GOCE g...

  16. Enhancement of xenon dynamical forecasts for PWR guiding systems using variational data assimilation

    International Nuclear Information System (INIS)

    In pressurised water reactors, the concentration of the nuclear fission product xenon-135 can exhibit axial oscillations which have to be controlled for safety reasons, related to spatial oscillations of in-core power. The evolution of the xenon concentration depends non-linearly on the concentration of the fission product iodine-135. This non-linearity represents a challenge for the prediction of oscillations. We investigate two variational data assimilation methods to improve the accuracy of the prediction of the xenon concentration. Data assimilation techniques are widely used in meteorology and oceanography to obtain more precise estimates of initial states. These methods combine all available pieces of information about the system such as the model prediction, a prior estimate of the true state, and physical measurements. The different sources of information are weighted according to their accuracy by the means of error covariance matrices. In our work, we propose one 3DVAR and one 4DVAR scheme for xenon dynamics. These schemes were tested in a twin experiment setting using the CIREP1D simulation code. CIREP1D implements a mono-dimensional coupled model of xenon dynamics, thermal, and thermal-hydraulic processes. Numerical experiments show that the proposed data assimilation schemes improve the accuracy of the xenon forecast. (authors)

  17. Variational Assimilation for Xenon Dynamical Forecasts in Neutronic using Advanced Background Error Covariance Matrix

    CERN Document Server

    Ponçot, Angélique; Bouriquet, Bertrand; Erhard, Patrick; Gratton, Serge; Thual, Olivier

    2013-01-01

    Data assimilation method consists in combining all available pieces of information about a system to obtain optimal estimates of initial states. The different sources of information are weighted according to their accuracy by the means of error covariance matrices. Our purpose here is to evaluate the efficiency of variational data assimilation for the xenon induced oscillations forecasts in nuclear cores. In this paper we focus on the comparison between 3DVAR schemes with optimised background error covariance matrix B and a 4DVAR scheme. Tests were made in twin experiments using a simulation code which implements a mono-dimensional coupled model of xenon dynamics, thermal, and thermal-hydraulic processes. We enlighten the very good efficiency of the 4DVAR scheme as well as good results with the 3DVAR one using a careful multivariate modelling of B.

  18. Continuing dynamic assimilation of the inner region data in hydrodynamics modelling: Optimization approach

    CERN Document Server

    Pisnichenko, F I; Martínez, J M; Santos, S A

    2008-01-01

    In meteorological and oceanological studies the classical approach for finding the numerical solution of the regional model consists in formulating and solving the Cauchy-Dirichlet problem. The related boundary conditions are obtained by linear interpolation of data available on a coarse grid (global data), to the boundary of regional model. Errors, in boundary conditions, appearing owing to linear interpolation may lead to increasing errors in numerical solution during integration. The methods developed to reduce these errors deal with continuous dynamic assimilation of known global data available inside the regional domain. Essentially, this assimilation procedure performs a nudging of large-scale component of regional model solution to large-scale global data component by introducing the relaxation forcing terms into the regional model equations. As a result, the obtained solution is not a valid numerical solution of the original regional model. In this work we propose the optimization approach which is fr...

  19. The Los Alamos dynamic radiation environment assimilation model (DREAM) for space weather specification and forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Geoffrey D [Los Alamos National Laboratory; Friedel, Reiner H W [Los Alamos National Laboratory; Chen, Yue [Los Alamos National Laboratory; Koller, Josef [Los Alamos National Laboratory; Henderson, Michael G [Los Alamos National Laboratory

    2008-01-01

    The Dynamic Radiation Environment Assimilation Model (DREAM) was developed at Los Alamos National Laboratory to assess, quantify, and predict the hazards from the natural space environment and the anthropogenic environment produced by high altitude nuclear explosions (HANE). DREAM was initially developed as a basic research activity to understand and predict the dynamics of the Earth's Van Allen radiation belts. It uses Kalman filter techniques to assimilate data from space environment instruments with a physics-based model of the radiation belts. DREAM can assimilate data from a variety of types of instruments and data with various levels of resolution and fidelity by assigning appropriate uncertainties to the observations. Data from any spacecraft orbit can be assimilated but DREAM was designed to function with as few as two spacecraft inputs: one from geosynchronous orbit and one from GPS orbit. With those inputs, DREAM can be used to predict the environment at any satellite in any orbit whether space environment data are available in those orbits or not. Even with very limited data input and relatively simple physics models, DREAM specifies the space environment in the radiation belts to a high level of accuracy. DREAM has been extensively tested and evaluated as we transition from research to operations. We report here on one set of test results in which we predict the environment in a highly-elliptical polar orbit. We also discuss long-duration reanalysis for spacecraft design, using DREAM for real-time operations, and prospects for 1-week forecasts of the radiation belt environment.

  20. Hypnopompic seizures.

    Science.gov (United States)

    Awad, Amer M; Lüders, Hans O

    2010-12-01

    The relationship between epilepsy and sleep is complex and bidirectional. Ictal awakening is probably a common and well-described phenomenon. In this small observational study we describe arousal from sleep as the only, or at least main, manifestation of some epileptic seizures. We coin the term "hypnopompic seizures" to describe this entity. Five patients with intractable epilepsy were monitored by continuous video-electroencephalogram. Four of them had left temporal lobe epilepsy and one patient had generalised epilepsy. Hypnopompic seizures accounted for 30-100% of their seizure types captured during monitoring. All the seizures occurred during stage II sleep and were brief. Hypnopompic seizures are extremely subtle and may be underdiagnosed and underreported. Future larger studies are needed to shed some light on this unique entity and its neuropathophysiology. Epileptologists should be aware of this type of seizure and careful review of electroencephalograms during the transition from sleep to arousal is imperative to capture these seizures. Physicians, patients and families also need to be aware of such a subtle manifestation of seizures. Improved awareness of hypnopompic seizures and subtle seizures, in general, help guide accurate and early diagnosis, thorough monitoring and appropriate management. PMID:21030341

  1. Assimilative model for ionospheric dynamics employing delay, Doppler, and direction of arrival measurements from multiple HF channels

    Science.gov (United States)

    Fridman, Sergey V.; Nickisch, L. J.; Hausman, Mark; Zunich, George

    2016-03-01

    We describe the development of new HF data assimilation capabilities for our ionospheric inversion algorithm called GPSII (GPS Ionospheric Inversion). Previously existing capabilities of this algorithm included assimilation of GPS total electron content data as well as assimilation of backscatter ionograms. In the present effort we concentrated on developing assimilation tools for data related to HF propagation channels. Measurements of propagation delay, angle of arrival, and the ionosphere-induced Doppler from any number of known propagation links can now be utilized by GPSII. The resulting ionospheric model is consistent with all assimilated measurements. This means that ray tracing simulations of the assimilated propagation links are guaranteed to be in agreement with measured data within the errors of measurement. The key theoretical element for assimilating HF data is the raypath response operator (RPRO) which describes response of raypath parameters to infinitesimal variations of electron density in the ionosphere. We construct the RPRO out of the fundamental solution of linearized ray tracing equations for a dynamic magnetoactive plasma. We demonstrate performance and internal consistency of the algorithm using propagation delay data from multiple oblique ionograms (courtesy of Defence Science and Technology Organisation, Australia) as well as with time series of near-vertical incidence sky wave data (courtesy of the Intelligence Advanced Research Projects Activity HFGeo Program Government team). In all cases GPSII produces electron density distributions which are smooth in space and in time. We simulate the assimilated propagation links by performing ray tracing through GPSII-produced ionosphere and observe that simulated data are indeed in agreement with assimilated measurements.

  2. Dynamic control of modeled tonic-clonic seizure states with closed-loop stimulation

    Directory of Open Access Journals (Sweden)

    Bryce eBeverlin II

    2013-02-01

    Full Text Available Seizure control using deep brain stimulation (DBS provides an alternative therapy to patients with intractable and drug resistant epilepsy. This paper presents novel DBS stimulus protocols to disrupt seizures. Two protocols are presented: open-loop stimulation and a closed-loop feedback system utilizing measured firing rates to adjust stimulus frequency. Stimulation suppression is demonstrated in a computational model using 3000 excitatory Morris-Lecar model neurons connected with depressing synapses. Cells are connected using second order network topology to simulate network topologies measured in cortical networks. The network spontaneously switches from tonic to clonic as synaptic strengths and tonic input to the neurons decreases. To this model we add periodic stimulation pulses to simulate DBS. Periodic forcing can synchronize or desynchronize an oscillating population of neurons, depending on the stimulus frequency and amplitude. Therefore, it is possible to either extend or truncate the tonic or clonic phases of the seizure. Stimuli applied at the firing rate of the neuron generally synchronize the population while stimuli slightly slower than the firing rate prevent synchronization. We present an adaptive stimulation algorithm that measures the firing rate of a neuron and adjusts the stimulus to maintain a relative stimulus frequency to firing frequency and demonstrate it in a computational model of a tonic-clonic seizure. This adaptive algorithm can affect the duration of the tonic phase using much smaller stimulus amplitudes than the open-loop control.

  3. Dynamical and Microphysical Retrieval from Simulated Doppler Radar Observations Using the 4DVAR Assimilation Technique

    Institute of Scientific and Technical Information of China (English)

    XU Xiaoyong; LIU Liping; ZHENG Guoguang

    2005-01-01

    Based on a cloud model and the four-dimensional variational (4DVAR) data assimilation method developed by Sun and Crook (1997), simulated experiments of dynamical and microphysical retrieval from Doppler radar data were performed. The 4DVAR data assimilation technique was applied to a cloud scale model with a warm rain parameterization scheme. The 3D wind, thermodynamical, and microphysical fields were determined by minimizing a cost function, defined by the difference between both radar observed radial velocities and reflectivities and their model predictions. The adjoint of the numerical model was used to provide the gradient of the cost function with respect to the control variables. Experiments have demonstrated that the 4DVAR assimilation method is able to retrieve the detailed structure of wind, thermodynamics, and microphysics by using either dual-Doppler or single-Doppler information. The quality of retrieval depends strongly on the magnitude of constraint with respect to the variables. Retrieving the temperature field,cloud water and water vapor is more difficult than the recovery of the wind field and rainwater. Accurate thermodynamic retrieval requires a longer assimilation period. The inclusion of a background term, even mean fields from a single sounding, helped reduce the retrieval errors. Less accurate velocity fields were obtained when single-Doppler data were used. It was found that the retrieved velocity is sensitive to the location of the retrieval domain relative to the radars while the other fields have very little changes. Two radar volumetric scans are generally adequate for providing the evolution, although the use of additional volumes improves the retrieval. As the amount of the observations decreases, the performance of the retrieval is degraded. However, the missing observations can be compensated by adding a background term to the cost function. The technique is robust to random errors in radial velocity and calibration errors in

  4. Transfer of Real-time Dynamic Radiation Environment Assimilation Model; Research to Operation

    Science.gov (United States)

    Cho, K. S. F.; Hwang, J.; Shin, D. K.; Kim, G. J.; Morley, S.; Henderson, M. G.; Friedel, R. H.; Reeves, G. D.

    2015-12-01

    Real-time Dynamic Radiation Environment Assimilation Model (rtDREAM) was developed by LANL for nowcast of energetic electrons' flux at the radiation belt to quantify potential risks from radiation damage at the satellites. Assimilated data are from multiple sources including LANL assets (GEO, GPS). For transfer from research to operation of the rtDREAM code, LANL/KSWC/NOAA makes a Memorandum Of Understanding (MOU) on the collaboration between three parts. By this MOU, KWSC/RRA provides all the support for transitioning the research version of DREAM to operations. KASI is primarily responsible for providing all the interfaces between the current scientific output formats of the code and useful space weather products that can be used and accessed through the web. In the second phase, KASI will be responsible in performing the work needed to transform the Van Allen Probes beacon data into "DREAM ready" inputs. KASI will also provide the "operational" code framework and additional data preparation, model output, display and web page codes back to LANL and SWPC. KASI is already a NASA partnering ground station for the Van Allen Probes' space weather beacon data and can here show use and utility of these data for comparison between rtDREAM and observations by web. NOAA has offered to take on some of the data processing tasks specific to the GOES data.

  5. The dynamic nature of assimilation and accommodation procedures in the brains of Chinese-English and English-Chinese bilinguals.

    Science.gov (United States)

    Sun, Yafeng; Peng, Danling; Ding, Guosheng; Qi, Ting; Desroches, Amy S; Liu, Li

    2015-10-01

    The framework of assimilation and accommodation has been proposed to explain the brain mechanisms supporting second language reading acquisition (Perfetti et al. [2007]: Bilingual Lang Cogn 10:131). Assimilation refers to using the procedures of the native language network in the acquisition of a new writing system, whereas accommodation refers to using second language procedures for reading the newly acquired writing system. We investigated assimilation and accommodation patterns in the brains of bilingual individuals by recruiting a group of Chinese-English bilinguals and a group of English-Chinese bilinguals to perform lexical decision tasks in both English and Chinese. The key question was whether the assimilation/accommodation procedures supporting second language reading in the brains of Chinese-English and English-Chinese bilinguals were dynamic, i.e., modulated by proficiency in the second language and perceptual features of the second language's script. Perceptual features of the scripts were manipulated through orthographic degradation by inserting spaces between the radicals of a Chinese character or between the syllables of an English word. This manipulation disrupts the visual configuration of the orthography but does not change its more fundamental design principles. We found that for English-Chinese bilinguals, higher proficiency was associated with greater accommodation, suggesting that the accommodation procedure in a bilingual individual's brain is modulated by second language proficiency. Most interestingly, we found that the assimilation/accommodation effects vanished or diminished when orthographically degraded scripts were processed by both Chinese-English and English-Chinese bilinguals, suggesting that the assimilation/accommodation procedures in a bilingual individual's brain are modulated by perceptual features of orthography. This work therefore offers a new, dynamic perspective for our understanding of the assimilation

  6. Insights on radiation belt physics from the dynamics radiation environment assimilation model, DREAM

    International Nuclear Information System (INIS)

    Complete text of publication follows. The Dynamic Radiation Environment Assimilation Model (DREAM) is a coupled, inner magnetosphere model with modules that include the ring current, the radiation belts, self-consistent global magnetic fields, Kalman filter data assimilation, and customized user applications. DREAM was developed at Los Alamos National Laboratory with the goals of specifying, predicting and understanding the near-Earth space environment. Here we will focus on new understanding of physics of the inner magnetosphere that DREAM has provided and, even more specifically, on the physics of radiation belt acceleration, transport, and loss. One early and important contribution was providing definitive evidence that local acceleration processes acting inside or near geosynchronous orbit are required in order to explain radiation belt dynamics. Another critical process we investigated was loss of radiation belt electrons by radial diffusion or transport to the magnetopause. A critical calculation here is accurate determination of the adiabatic redistribution of particles due to the storm-time ring current (the 'Dst' effect) which can cause both apparent 'loss' of particles at a given satellite. At different times and at different energies, DREAM can determine whether the region outside the trapping boundary acts as a source (the plasma sheet) a sink (the magnetopause) or a combination of both. Another fundamental sink of radiation belt electrons is the atmospheric loss cone where pitch angle scattering can remove electrons trough precipitation. In the final topic for this talk we will describe how we use DREAM to determine the relationship between trapped and precipitating populations and how we relate LEO measurements to high-altitude measurements using observed and modeled characteristics of magnetospheric wave populations.

  7. Local changes in neocortical circuit dynamics coincide with the spread of seizures to thalamus in a model of epilepsy

    Directory of Open Access Journals (Sweden)

    Florian B Neubauer

    2014-09-01

    Full Text Available During the generalization of epileptic seizures, pathological activity in one brain area recruits distant brain structures into joint synchronous discharges. However, it remains unknown whether specific changes in local circuit activity are related to the aberrant recruitment of anatomically distant structures into epileptiform discharges. Further, it is not known whether aberrant areas recruit or entrain healthy ones into pathological activity. Here we study the dynamics of local circuit activity during the spread of epileptiform discharges in the zero-magnesium in vitro model of epilepsy. We employ high-speed multi-photon imaging in combination with dual whole-cell recordings in acute thalamocortical slices of the juvenile mouse to characterize the generalization of epileptic activity between neocortex and thalamus. We find that, although both structures are exposed to zero-magnesium, the initial onset of focal epileptiform discharge occurs in cortex. This suggests that local recurrent connectivity that is particularly prevalent in cortex is important for the initiation of seizure activity. Subsequent recruitment of thalamus into joint, generalized discharges is coincident with an increase in the coherence of local cortical circuit activity that itself does not depend on thalamus. Finally, the intensity of population discharges is positively correlated between both brain areas. This suggests that during and after seizure generalization not only the timing but also the amplitude of epileptiform discharges in thalamus is entrained by cortex. Together these results suggest a central role of neocortical activity for the onset and the structure of pathological recruitment of thalamus into joint synchronous epileptiform discharges.

  8. Wavelet-based Gaussian-mixture hidden Markov model for the detection of multistage seizure dynamics: A proof-of-concept study

    Directory of Open Access Journals (Sweden)

    Carlen Peter L

    2011-04-01

    validated with experimental intracellular electrical recordings of seizures. Conclusions The HMM implementation of a seizure dynamics detector is an improvement over existing approaches using visual detection and complexity measures. The subjectivity involved in partitioning the observed data prior to training can be eliminated. It can also decipher the probabilities of seizure state transitions using the magnitude and rate of change wavelet information of the LFPs.

  9. System characterization of neuronal excitability in the hippocampus and its relevance to observed dynamics of spontaneous seizure-like transitions

    Science.gov (United States)

    Zalay, Osbert C.; Serletis, Demitre; Carlen, Peter L.; Bardakjian, Berj L.

    2010-06-01

    Most forms of epilepsy are marked by seizure episodes that arise spontaneously. The low-magnesium/high-potassium (low-Mg2+/high-K+) experimental model of epilepsy is an acute model that produces spontaneous, recurring seizure-like events (SLEs). To elucidate the nature of spontaneous seizure transitions and their relationship to neuronal excitability, whole-cell recordings from the intact hippocampus were undertaken in vitro, and the response of hippocampal CA3 neurons to Gaussian white noise injection was obtained before and after treatment with various concentrations of low-Mg2+/high-K+ solution. A second-order Volterra kernel model was estimated for each of the input-output response pairs. The spectral energy of the responses was also computed, providing a quantitative measure of neuronal excitability. Changes in duration and amplitude of the first-order kernel correlated positively with the spectral energy increase following treatment with low-Mg2+/high-K+ solution, suggesting that variations in neuronal excitability are coded by the system kernels, in part by differences to the profile of the first-order kernel. In particular, kernel duration was more sensitive than amplitude to changes in spectral energy, and correlated more strongly with kernel area. An oscillator network model of the hippocampal CA3 was constructed to investigate the relationship of kernel duration to network excitability, and the model was able to generate spontaneous, recurrent SLEs by increasing the duration of a mode function analogous to the first-order kernel. Results from the model indicated that disruption to the dynamic balance of feedback was responsible for seizure-like transitions and the observed intermittency of SLEs. A physiological candidate for feedback imbalance consistent with the network model is the destabilizing interaction of extracellular potassium and paroxysmal neuronal activation. Altogether, these results (1) validate a mathematical model for epileptiform

  10. Capturing Dynamics in the Power Grid: Formulation of Dynamic State Estimation through Data Assimilation

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Ning; Huang, Zhenyu; Meng, Da; Elbert, Stephen T.; Wang, Shaobu; Diao, Ruisheng

    2014-03-31

    With the increasing complexity resulting from uncertainties and stochastic variations introduced by intermittent renewable energy sources, responsive loads, mobile consumption of plug-in vehicles, and new market designs, more and more dynamic behaviors are observed in everyday power system operation. To operate a power system efficiently and reliably, it is critical to adopt a dynamic paradigm so that effective control actions can be taken in time. The dynamic paradigm needs to include three fundamental components: dynamic state estimation; look-ahead dynamic simulation; and dynamic contingency analysis (Figure 1). These three components answer three basic questions: where the system is; where the system is going; and how secure the system is against accidents. The dynamic state estimation provides a solid cornerstone to support the other 2 components and is the focus of this study.

  11. Febrile Seizures

    Science.gov (United States)

    ... Order Brochures News From NINDS Funding Information Research Programs Training & Career Awards Enhancing Diversity Find People About NINDS Febrile Seizures Fact Sheet See a list of all NINDS Disorders Get Web page suited for printing Email this to a friend ...

  12. Febrile Seizures

    OpenAIRE

    Mewasingh, Leena D

    1982-01-01

    Febrile seizure (FS) is the most common seizure disorder of childhood, and occurs in an age-related manner. FS are classified into simple and complex. FS has a multifactorial inheritance, suggesting that both genetic and environmental factors are causative. Various animal models have elucidated the pathophysiological mechanisms of FS. Risk factors for a first FS are a family history of the disorder and a developmental delay. Risk factors for recurrent FS are a family history, age below 18 mon...

  13. Assimilation of Images

    OpenAIRE

    Vidard, Arthur; Titaud, Olivier

    2014-01-01

    International audience Data assimilation aims at determining as accurately as possible the state of a dynamical system by combining heterogeneous sources of information in an optimal way. Generally speaking, the mathematical methods of data assimilation describe algorithms for forming optimal combinations of observations of a system, a numerical model that describes its evolution, and appropriate prior information. Data assimilation has a long history of application to high-dimensional geo...

  14. Impact of assimilating physical oceanographic data on modeled ecosystem dynamics in the California Current System

    Science.gov (United States)

    Raghukumar, Kaustubha; Edwards, Christopher A.; Goebel, Nicole L.; Broquet, Gregoire; Veneziani, Milena; Moore, Andrew M.; Zehr, Jon P.

    2015-11-01

    A method to model ocean ecosystems using data-constrained physical circulation estimates is investigated. Physical oceanographic data is assimilated into a Regional Ocean Modeling System implementation of the California Current System using an incremental 4-Dimensional Variational method. The resulting state estimate drives a complex, self-assembling ocean ecosystem model for the year 2003, and results are evaluated against SeaWiFS surface and CalCOFI subsurface observations and with ecosystem model output driven by an unconstrained physical model. While physical data assimilation improves correlation with observations, this method also drives elevated levels of phytoplankton standing stock, leading to a large bias particularly in regions of low mean concentration. We identify two causes for this increase: biological rectification of fluctuating vertical nutrient transport due to gravity wave generation at assimilation cycle initialization and increased nutrient variance on density surfaces. We investigate one and propose other possible remedies for these deleterious side-effects of this data assimilation method.

  15. Controlling Seizures

    Science.gov (United States)

    Henderson, Nancy

    2008-01-01

    This article describes how an implantable device could greatly improve the quality of life for people with epilepsy. Gabe Anderson was diagnosed with bilateral heterotopia, a congenital condition that can lead to the onset of complex partial seizures stemming from both hemispheres of the brain. In early 2004, Gabe became one of the first 35…

  16. The assimilation of spectral sensing and the WOFOST model for the dynamic simulation of cadmium accumulation in rice tissues

    Science.gov (United States)

    Wu, Ling; Liu, Xiangnan; Wang, Ping; Zhou, Botian; Liu, Meiling; Li, Xuqing

    2013-12-01

    The accurate detection of heavy metal-induced stress on crop growth is important for food security and agricultural, ecological and environmental protection. Spectral sensing offers an efficient and undamaged observation tool to monitor soil and vegetation contamination. This study proposed a methodology for dynamically estimating the total cadmium (Cd) accumulation in rice tissues by assimilating spectral information into WOFOST (World Food Study) model. Based on the differences among ground hyperspectral data of rice in three experiments fields under different Cd concentration levels, the spectral indices MCARI1, NREP and RH were selected to reflect the rice stress condition and dry matter production of rice. With assimilating these sensitive spectral indices into the WOFOST + PROSPECT + SAIL model to optimize the Cd pollution stress factor fwi, the dynamic dry matter production processes of rice were adjusted. Based on the relation between dry matter production and Cd accumulation, we dynamically simulating the Cd accumulation in rice tissues. The results showed that the method performed well in dynamically estimating the total amount of Cd accumulation in rice tissues with R2 over 85%. This study suggests that the proposed method of integrating the spectral information and the crop growth model could successfully dynamically simulate the Cd accumulation in rice tissues.

  17. Seizures and Teens: Stress, Sleep, & Seizures

    Science.gov (United States)

    Shafer, Patricia Osborne

    2007-01-01

    Most parents are used to erratic sleep patterns and mood swings in their teenagers. When these occur in an adolescent with seizures, however, the parent may wonder if sleep and mood problems are related to seizures. Sorting out the cause and effects of sleep in an adolescent with seizures can be confusing. Since stress can be a contributor to both…

  18. In vivo imaging of seizure activity in a novel developmental seizure model.

    Science.gov (United States)

    Hewapathirane, D Sesath; Dunfield, Derek; Yen, Wesley; Chen, Simon; Haas, Kurt

    2008-06-01

    The immature brain is exceptionally susceptible to seizures. However, it remains unclear whether seizures occurring during development affect critical processes underlying neural circuit formation, leading to long-term functional consequences. Here we characterize a novel in vivo model system of developmental seizures based on the transparent albino Xenopus laevis tadpole, which allows direct examination of seizure activity, and seizure-induced effects on neuronal development within the intact unanesthetized brain. Pentylenetetrazol (PTZ), kainic acid, bicuculline, picrotoxin, 4-aminopyridine, and pilocarpine were tested for their ability to induce behavioral seizures in freely swimming tadpoles when bath applied. All six chemoconvulsants consistently induced similar patterns of abnormal behavior in a dose-dependent manner, characterized by convulsive clonus-like motor patterns with periods of behavioral arrest. Extracellular field recordings demonstrated rhythmic synchronous epileptiform electrographic responses induced by convulsants irrespective of mechanism of action, that could be terminated by the anti-epileptic drug valproate. PTZ-induced seizures were further characterized using in vivo two-photon fluorescence imaging of neuronal calcium dynamics, in unanesthetized immobilized tadpoles. Imaging of calcium dynamics during PTZ-induced seizures revealed waves of neural activity propagating through large populations of neurons within the brain. Analysis of single-cell responses demonstrated distinct synchronized high-amplitude calcium spikes not observed under baseline conditions. Similar to other developmental seizure models, prolonged seizures failed to induce marked neuronal death within the brain, detected by cellular propidium iodide incorporation in vivo or TUNEL labeling. This novel developmental seizure model system has distinct advantages for controlled seizure induction, and direct visualization of both seizure activity and seizure-induced effects on

  19. Visualization of spatiotemporal energy dynamics of hippocampal neurons by mass spectrometry during a kainate-induced seizure.

    Directory of Open Access Journals (Sweden)

    Yuki Sugiura

    Full Text Available We report the use of matrix-assisted laser desorption/ionization (MALDI imaging mass spectrometry combined with capillary electrophoresis (CE mass spectrometry to visualize energy metabolism in the mouse hippocampus by imaging energy-related metabolites. We show the distribution patterns of ATP, ADP, and AMP in the hippocampus as well as changes in their amounts and distribution patterns in a murine model of limbic, kainate-induced seizure. As an acute response to kainate administration, we found massive and moderate reductions in ATP and ADP levels, respectively, but no significant changes in AMP levels--especially in cells of the CA3 layer. The results suggest the existence of CA3 neuron-selective energy metabolism at the anhydride bonds of ATP and ADP in the hippocampal neurons during seizure. In addition, metabolome analysis of energy synthesis pathways indicates accelerated glycolysis and possibly TCA cycle activity during seizure, presumably due to the depletion of ATP. Consistent with this result, the observed energy depletion significantly recovered up to 180 min after kainate administration. However, the recovery rate was remarkably low in part of the data-pixel population in the CA3 cell layer region, which likely reflects acute and CA3-selective neural death. Taken together, the present approach successfully revealed the spatiotemporal energy metabolism of the mouse hippocampus at a cellular resolution--both quantitatively and qualitatively. We aim to further elucidate various metabolic processes in the neural system.

  20. Stratospheric Assimilation of Chemical Tracer Observations Using a Kalman Filter. Pt. 2; Chi-Square Validated Results and Analysis of Variance and Correlation Dynamics

    Science.gov (United States)

    Menard, Richard; Chang, Lang-Ping

    1998-01-01

    A Kalman filter system designed for the assimilation of limb-sounding observations of stratospheric chemical tracers, which has four tunable covariance parameters, was developed in Part I (Menard et al. 1998) The assimilation results of CH4 observations from the Cryogenic Limb Array Etalon Sounder instrument (CLAES) and the Halogen Observation Experiment instrument (HALOE) on board of the Upper Atmosphere Research Satellite are described in this paper. A robust (chi)(sup 2) criterion, which provides a statistical validation of the forecast and observational error covariances, was used to estimate the tunable variance parameters of the system. In particular, an estimate of the model error variance was obtained. The effect of model error on the forecast error variance became critical after only three days of assimilation of CLAES observations, although it took 14 days of forecast to double the initial error variance. We further found that the model error due to numerical discretization as arising in the standard Kalman filter algorithm, is comparable in size to the physical model error due to wind and transport modeling errors together. Separate assimilations of CLAES and HALOE observations were compared to validate the state estimate away from the observed locations. A wave-breaking event that took place several thousands of kilometers away from the HALOE observation locations was well captured by the Kalman filter due to highly anisotropic forecast error correlations. The forecast error correlation in the assimilation of the CLAES observations was found to have a structure similar to that in pure forecast mode except for smaller length scales. Finally, we have conducted an analysis of the variance and correlation dynamics to determine their relative importance in chemical tracer assimilation problems. Results show that the optimality of a tracer assimilation system depends, for the most part, on having flow-dependent error correlation rather than on evolving the

  1. An eddy-permitting, dynamically consistent adjoint-based assimilation system for the tropical Pacific: Hindcast experiments in 2000

    KAUST Repository

    Hoteit, Ibrahim

    2010-03-02

    An eddy-permitting adjoint-based assimilation system has been implemented to estimate the state of the tropical Pacific Ocean. The system uses the Massachusetts Institute of Technology\\'s general circulation model and its adjoint. The adjoint method is used to adjust the model to observations by controlling the initial temperature and salinity; temperature, salinity, and horizontal velocities at the open boundaries; and surface fluxes of momentum, heat, and freshwater. The model is constrained with most of the available data sets in the tropical Pacific, including Tropical Atmosphere and Ocean, ARGO, expendable bathythermograph, and satellite SST and sea surface height data, and climatologies. Results of hindcast experiments in 2000 suggest that the iterated adjoint-based descent is able to significantly improve the model consistency with the multivariate data sets, providing a dynamically consistent realization of the tropical Pacific circulation that generally matches the observations to within specified errors. The estimated model state is evaluated both by comparisons with observations and by checking the controls, the momentum balances, and the representation of small-scale features that were not well sampled by the observations used in the assimilation. As part of these checks, the estimated controls are smoothed and applied in independent model runs to check that small changes in the controls do not greatly change the model hindcast. This is a simple ensemble-based uncertainty analysis. In addition, the original and smoothed controls are applied to a version of the model with doubled horizontal resolution resulting in a broadly similar “downscaled” hindcast, showing that the adjustments are not tuned to a single configuration (meaning resolution, topography, and parameter settings). The time-evolving model state and the adjusted controls should be useful for analysis or to supply the forcing, initial, and boundary conditions for runs of other models.

  2. Assimilation of space-based passive microwave soil moisture retrievals and the correction for a dynamic open water fraction

    Directory of Open Access Journals (Sweden)

    B. T. Gouweleeuw

    2012-01-01

    Full Text Available The large observation footprint of low-frequency satellite microwave emissions complicates the interpretation of near-surface soil moisture retrievals. While the effect of sub-footprint lateral heterogeneity is relatively limited under unsaturated conditions, open water bodies, if not accounted for, cause a strong positive bias in the satellite-derived soil moisture retrieval. This bias is generally assumed static and associated with large, continental lakes and coastal areas. Temporal changes in the extent of smaller water bodies as small as a few percent of the sensor footprint size, however, can cause significant and dynamic biases. We analysed the influence of such small open water bodies near-surface soil moisture retrieval data from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E for three areas in Oklahoma, USA. Differences between on-ground observations, model estimates and AMSR-E retrievals were compared to dynamic estimates of open water fraction, one retrieved from a global daily record based on higher frequency AMSR-E data and another derived from the Moderate Resolution Imaging Spectroradiometer (MODIS. The comparisons demonstrates that seasonally varying biases of up to 30 vol.% soil water content can be attributed to the presence of relatively small areas (<5% of open water in or near the sensor footprint. These errors need to be addressed, either through elimination or accurate characterization, if the soil moisture retrievals are to be used effectively in a data assimilation scheme.

  3. Code blue: seizures.

    Science.gov (United States)

    Hoerth, Matthew T; Drazkowski, Joseph F; Noe, Katherine H; Sirven, Joseph I

    2011-06-01

    Eyewitnesses frequently perceive seizures as life threatening. If an event occurs on the hospital premises, a "code blue" can be called which consumes considerable resources. The purpose of this study was to determine the frequency and characteristics of code blue calls for seizures and seizure mimickers. A retrospective review of a code blue log from 2001 through 2008 identified 50 seizure-like events, representing 5.3% of all codes. Twenty-eight (54%) occurred in inpatients; the other 22 (44%) events involved visitors or employees on the hospital premises. Eighty-six percent of the events were epileptic seizures. Seizure mimickers, particularly psychogenic nonepileptic seizures, were more common in the nonhospitalized group. Only five (17.9%) inpatients had a known diagnosis of epilepsy, compared with 17 (77.3%) of the nonhospitalized patients. This retrospective survey provides insights into how code blues are called on hospitalized versus nonhospitalized patients for seizure-like events. PMID:21546315

  4. Reconstructing three-dimensional reentrant cardiac electrical wave dynamics using data assimilation

    Science.gov (United States)

    Hoffman, M. J.; LaVigne, N. S.; Scorse, S. T.; Fenton, F. H.; Cherry, E. M.

    2016-01-01

    For many years, reentrant scroll waves have been predicted and studied as an underlying mechanism for cardiac arrhythmias using numerical techniques, and high-resolution mapping studies using fluorescence recordings from the surfaces of cardiac tissue preparations have confirmed the presence of visible spiral waves. However, assessing the three-dimensional dynamics of these reentrant waves using experimental techniques has been limited to verifying stable scroll-wave dynamics in relatively thin preparations. We propose a different approach to recovering the three-dimensional dynamics of reentrant waves in the heart. By applying techniques commonly used in weather forecasting, we combine dual-surface observations from a particular experiment with predictions from a numerical model to reconstruct the full three-dimensional time series of the experiment. Here, we use model-generated surrogate observations from a numerical experiment to evaluate the performance of the ensemble Kalman filter in reconstructing such time series for a discordant alternans state in one spatial dimension and for scroll waves in three dimensions. We show that our approach is able to recover time series of both observed and unobserved variables matching the truth. Where nearby observations are available, the error is reduced below the synthetic observation error, with a smaller reduction with increased distance from observations. Our findings demonstrate that state reconstruction for spatiotemporally complex cardiac electrical dynamics is possible and will lead naturally to applications using real experimental data.

  5. Novel bursting mode leads to seizure termination

    OpenAIRE

    Giri Krishnan; Andrey Shilnikov

    2012-01-01

    Many types of seizure manifest themselves in stereotype patterns of electrical activity characterized by alternations of the spike/polyspike and wave (SW/PSW) EEG discharges and fast runs of EEG spikes. This includes absence seizures (typical and atypical), absence status epilepticus, Lennox Gastault syndrome, West syndrome, and posttraumatic epilepsy [Niedermeyer, 2005]. However, the dynamics and the mechanisms of transitions between fast spiking (tonic activity) and SW/PSW complexes (bursti...

  6. : Seizure onset zone imaging

    OpenAIRE

    David, Olivier; Blauwblomme, Thomas; Job, Anne-Sophie; Chabardès, Stéphan; Hoffmann, Dominique,; Minotti, Lorella; Kahane, Philippe

    2011-01-01

    International audience Stereo-electroencephalography is used to localize the seizure onset zone and connected neuronal networks in surgical candidates suffering from intractable focal epilepsy. The concept of an epileptogenicity index has been proposed recently to represent the likelihood of various regions being part of the seizure onset zone. It quantifies low-voltage fast activity, the electrophysiological signature of seizure onset usually assessed visually by neurologists. Here, we re...

  7. Inhomogeneous cortical synchronization and partial epileptic seizures

    Directory of Open Access Journals (Sweden)

    Lorena Carolina Vega

    2014-09-01

    Full Text Available Objective: Interictal synchronization clusters have recently been described in several publications using diverse techniques, including neurophysiological recordings and fMRI, in patients suffering from epilepsy. However, little is known about the role of these hyper-synchronous areas during seizures. In this work, we report an analysis of synchronization clusters jointly with several network measures during seizure activity; we then discuss our findings in the context of prior literature. Methods: Subdural activity was recorded by electrocorticography (with sixty electrodes placed at temporal and parietal lobe locations in a patient with temporal lobe epilepsy with partial seizures with and without secondary generalization. Both interictal and ictal activities (during four seizures were investigated and characterized using local synchronization and complex network methodology. The modularity, density of links, average clustering coefficient and average path lengths were calculated to obtain information about the dynamics of the global network. Functional connectivity changes during the seizures were compared with the time-evolution of highly synchronized areas.Results: Our findings reveal temporal changes in local synchronization areas during seizures and a tight relationship between the cortical locations of these areas and the patterns of their evolution over time. Seizure evolution and secondary generalization appear to be driven by two different underlying mechanisms.

  8. FEBRILE SEIZURE AND ANEMIA

    Directory of Open Access Journals (Sweden)

    A. Talebian

    2008-11-01

    Full Text Available ObjectiveConsidering the controversial results in present day literature regarding the relationship between febrile seizures and anemia and the high rate of such seizures in children, this study was conducted to evaluate the association between pediatric febrile seizures and anemia.Material and MethodsIn this case-control study, conducted in 2003, 60 children with febrile seizure(cases and 60 febrile children without seizure(controls were evaluated in the Kashan Shahid Beheshti hospital; all patients were matched for age, sex, type of feeding, and use of supplemental iron. Thirty-six (60% and 39 (65% of the patients in case and control groups respectively were male, and the remaining female. Levels of hemoglobin, hematocrit, and red blood cell indices were determined in all children and Chi-square and Fisher exact tests were used to analyze data.ResultsOf the case group, 13.3% (6 male, 2 female and of controls, 20% (9 male, 3 female of children had anemia (p= 0.327, the condition being more common in male children aged over 6 months. Febrile seizures were found to occur mostly between the ages of 6 to 24 months.ConclusionThe risk of febrile seizure occurrence in anemic children seems to be less than that in children who do not suffer from the condition.Keywords:Febrile seizure, Anemia, Children

  9. Pharmacology of seizure drugs

    Czech Academy of Sciences Publication Activity Database

    Kubová, Hana

    Vol.2. Oxford : Academic Press, 2009 - (Schwartzkroin, P.), s. 780-786 ISBN 978-0-12-373688-8 R&D Projects: GA MŠk(CZ) LC554; GA MŠk ME08045 Institutional research plan: CEZ:AV0Z50110509 Keywords : seizure drug * epileptic seizure * postnataly development Subject RIV: FH - Neurology

  10. Management of provoked seizure

    Directory of Open Access Journals (Sweden)

    Misra Usha

    2011-01-01

    Full Text Available A provoked seizure may be due to structural damage (resulting from traumatic brain injury, brain tumor, stroke, tuberculosis, or neurocysticercosis or due to metabolic abnormalities (such as alcohol withdrawal and renal or hepatic failure. This article is a part of the Guidelines for Epilepsy in India. This article reviews the problem of provoked seizure and its management and also provides recommendations based on currently available information. Seizure provoked by metabolic disturbances requires correction of the triggering factors. Benzodiazepines are recommended for treatment of seizure due to alcohol withdrawal; gabapentin for seizure seen in porphyria; and antiepileptic drugs (AED, that are not inducer of hepatic enzymes, in the seizures seen in hepatic dysfunction. In severe traumatic brain injury, with or without seizure, phenytoin (PHT may be given for 7 days. In ischemic or hemorrhagic stroke one may individualize the AED therapy. In cerebral venous sinus thrombosis (CVST, AED may be prescribed if there is seizure or computed tomographic (CT abnormalities or focal weakness; the treatment, in these cases, has to be continued for 1 year. Prophylactic AED is not recommended in cases of brain tumor and neurosurgical procedures and if patient is on an AED it can be stopped after 1 week.

  11. Viruses and febrile seizures

    NARCIS (Netherlands)

    Zeijl, J.H. van

    2004-01-01

    We conclude that viral infections are the main cause of febrile seizures, with an important role for influenza A, HHV-6 and HHV-7. We showed that several viral infections not only contribute to initial febrile seizures, but also to recurrences. Viruses could not be detected in the CSF of children wi

  12. Particle Filter-based assimilation algorithms for improved estimation of root-zone soil moisture under dynamic vegetation conditions

    Science.gov (United States)

    Nagarajan, Karthik; Judge, Jasmeet; Graham, Wendy D.; Monsivais-Huertero, Alejandro

    2011-04-01

    In this study, we implement Particle Filter (PF)-based assimilation algorithms to improve root-zone soil moisture (RZSM) estimates from a coupled SVAT-vegetation model during a growing season of sweet corn in North Central Florida. The results from four different PF algorithms were compared with those from the Ensemble Kalman Filter (EnKF) when near-surface soil moisture was assimilated every 3 days using both synthetic and field observations. In the synthetic case, the PF algorithm with the best performance used residual resampling of the states and obtained resampled parameters from a uniform distribution and provided reductions of 76% in root mean square error (RMSE) over the openloop estimates. The EnKF provided the RZSM and parameter estimates that were closer to the truth than the PF with an 84% reduction in RMSE. When field observations were assimilated, the PF algorithm that maintained maximum parameter diversity offered the largest reduction of 16% in root mean square difference (RMSD) over the openloop estimates. Minimal differences were observed in the overall performance of the EnKF and PF using field observations since errors in model physics affected both the filters in a similar manner, with maximum reductions in RMSD compared to the openloop during the mid and reproductive stages.

  13. Dynamics of Control and Resistance: Reactions to the Modern Policy of Assimilation of the Travellers in Norway

    Directory of Open Access Journals (Sweden)

    Rune Halvorsen

    2004-07-01

    Full Text Available For much of the 20th century, the Norwegian authorities pursued a strict assimilation policy towards Travellers (tatere/ romanifolket and their culture. As was the case in many other countries, Travellers were constructed as "the other" (Riggins 1997, MacLaughlin 1999. When compared to other Western European countries, it is, however, surprising that Norwegian Travellers were seen as such a serious problem and threat during the 20th century. The 1845 census counted 1145 Travellers out of a total population of 1.3 million in Norway (Sundt 1852, SSB 1968: Table 13. A private charity organisation acting on behalf of the state registered 5129 "itinerants" in their archives from 1900 to 1959 (Haave 2000. These were the figures that worried the elites. This paper examines the modern assimilation policy and Travellers' reactions to this policy. In particular the paper analyses the internal relation between the modern assimilation policy and the emergence of collective demands for recognition as an ethnic minority and moral redress among Travellers in the 1990s.

  14. On the mathematics of data assimilation

    OpenAIRE

    Talagrand, Olivier

    2011-01-01

    The problem of convergence of a “forward-backward” assimilation is considered for the most general dynamical system. Using elementary techniques of stability theory, it is shown that the variation, over one assimilation cycle, of the difference between the assimilating model and the state to be reconstructed is, to the first order, determined by a perfectly defined amplification matrix. This leads to a straightforward criterion for convergence, depending on the eigenvalues of that matrix. Th...

  15. Mechanism of Seizure Termination

    OpenAIRE

    J Gordon Millichap

    2008-01-01

    Physiological mechanisms contributing to seizure termination and organized according to membranes, synapses, networks, and circuits are reviewed by researchers from Albert Einstein College of Medicine, and Montefiore Medical Center, Bronx, New York.

  16. Epileptic Seizures: Quakes of the brain?

    CERN Document Server

    Osorio, Ivan; Sornette, Didier; Milton, John; Lai, Ying-Cheng

    2007-01-01

    The concept of universality proposes that dynamical systems with the same power law behaviors are equivalent at large scales. We test this hypothesis on the Earth's crust and the epileptic brain, and discover that power laws also govern the distributions of seizure energies and recurrence times. This robust correspondence is extended over seven statistics, including the direct and inverse Omori laws. We also verify in an animal seizure model the earthquake-driven hypothesis that power law statistics co-exist with characteristic scales, as coupling between constitutive elements increases towards the synchronization regime. These observations point to the universality of the dynamics of coupled threshold oscillators for systems even as diverse as Earth and brain and suggest a general strategy for forecasting seizures, one of neurosciences' grails.

  17. Fibromyalgia and seizures.

    Science.gov (United States)

    Tatum, William O; Langston, Michael E; Acton, Emily K

    2016-06-01

    The purpose of this case-matched study was to determine how frequently fibromyalgia is associated with different paroxysmal neurological disorders and explore the utility of fibromyalgia as a predictor for the diagnosis of psychogenic non-epileptic seizures. The billing diagnosis codes of 1,730 new, non-selected patient encounters were reviewed over a three-year period for an epileptologist in a neurology clinic to identify all patients with historical diagnoses of fibromyalgia. The frequency with which epileptic seizures, psychogenic non-epileptic seizures, and physiological non-epileptic events were comorbid with fibromyalgia was assessed. Age and gender case-matched controls were used for a between-group comparison. Wilcoxon tests were used to analyse interval data, and Chi-square was used to analyse categorical data (pFibromyalgia was retrospectively identified in 95/1,730 (5.5%) patients in this cohort. Females represented 95% of the fibromyalgia sample (age: 53 years; 95% CI: 57, 51). Forty-three percent of those with fibromyalgia had a non-paroxysmal, neurological primary clinical diagnosis, most commonly chronic pain. Paroxysmal events were present in 57% of fibromyalgia patients and 54% of case-matched controls. Among patients with fibromyalgia and paroxysmal disorders, 11% had epileptic seizures, 74% had psychogenic non-epileptic seizures, and 15% had physiological non-epileptic events, compared to case-matched controls with 37% epileptic seizures, 51% psychogenic non-epileptic events, and 12% physiological non-epileptic events (p = 0.009). Fibromyalgia was shown to be a predictor for the diagnosis of psychogenic non-epileptic seizures in patients with undifferentiated paroxysmal spells. However, our results suggest that the specificity and sensitivity of fibromyalgia as a marker for psychogenic non-epileptic seizures in a mixed general neurological population of patients is less than previously described. PMID:27238051

  18. Seizures Induced by Music

    Directory of Open Access Journals (Sweden)

    A. O. Ogunyemi

    1993-01-01

    Full Text Available Musicogenic epilepsy is a rare disorder. Much remains to be learned about the electroclinical features. This report describes a patient who has been followed at our institution for 17 years, and was investigated with long-term telemetered simultaneous video-EEG recordings. She began to have seizures at the age of 10 years. She experienced complex partial seizures, often preceded by elementary auditory hallucination and complex auditory illusion. The seizures occurred in relation to singing, listening to music or thinking about music. She also had occasional generalized tonic clonic seizures during sleep. There was no significant antecedent history. The family history was negative for epilepsy. The physical examination was unremarkable. CT and MRI scans of the brain were normal. During long-term simultaneous video-EEG recordings, clinical and electrographic seizure activities were recorded in association with singing and listening to music. Mathematical calculation, copying or viewing geometric patterns and playing the game of chess failed to evoke seizures.

  19. Dynamic pattern of gene expression of ZnT-4, caspase-3, LC3, and PRG-3 in rat cerebral cortex following flurothyl-induced recurrent neonatal seizures.

    Science.gov (United States)

    Ni, Hong; Feng, Xing; Xiao, Zhuo-jun; Tao, Lu-yang; Jin, Mei-fang

    2011-12-01

    Zinc transporters, plasticity-related genes, and autophagic/apoptotic pathway both are associated with developmental seizure-induced brain excitotoxicity. Here, for the first time, we report the timing of expression pattern of zinc transporter 4 (ZnT-4), plasticity-related gene 3 (PRG-3), specific marker of autophagic vacuoles (LC3), and apoptotic marker caspase-3 in cerebral cortex following neonatal seizures. A seizure was induced by inhalant flurothyl daily in neonatal Sprague-Dawley rats from postnatal day 6 (P6). Rats were assigned into the recurrent-seizure group (RS, seizures induced in six consecutive days) and the control group. At 1.5 h, 3 h, 6 h, 12 h, 24 h, 48 h, 7 days, and 14 days after the last seizure, the mRNA level of the four genes in cerebral cortex was detected using RT-PCR method. At an early period 6 h or 12 h after the last seizures, both ZnT-4 and LC3 showed significantly up-regulated mRNA level while PRG-3 showed significantly down-regulated mRNA level at 12 h in cerebral cortex of RS group than those at the corresponding time point in control group. In the long-term time point of 7 days after the last seizure, the mRNA level of caspase-3 down-regulated; meanwhile, there was up-regulated mRNA level of LC-3 in RS group when compared to the control rats. This is the first report investigating the gene expression pattern of ZnT-4, PRG-3, LC-3, and caspase-3 in the developing brain. The results suggest that the disturbed expression pattern of the four genes might play a role in the pathophysiology of recurrent neonatal seizure-induced acute and long-term brain damage. PMID:21286846

  20. Assortative mixing in functional brain networks during epileptic seizures

    CERN Document Server

    Bialonski, Stephan

    2013-01-01

    We investigate assortativity of functional brain networks before, during, and after one-hundred epileptic seizures with different anatomical onset locations. We construct binary functional networks from multi-channel electroencephalographic data recorded from 60 epilepsy patients, and from time-resolved estimates of the assortativity coefficient we conclude that positive degree-degree correlations are inherent to seizure dynamics. While seizures evolve, an increasing assortativity indicates a segregation of the underlying functional network into groups of brain regions that are only sparsely interconnected, if at all. Interestingly, assortativity decreases already prior to seizure end. Together with previous observations of characteristic temporal evolutions of global statistical properties and synchronizability of epileptic brain networks, our findings may help to gain deeper insights into the complicated dynamics underlying generation, propagation, and termination of seizures.

  1. Epileptic seizures in supratentorial gliomas.

    Directory of Open Access Journals (Sweden)

    Tandon P

    2001-01-01

    Full Text Available Two hundred patients with supratentorial glioma; astrocytoma (pilocytic, fibrillary, gemistocytic 82, mixed glioma (oligoastrocytoma 46, oligodendroglioma 8, malignant (anaplastic astrocytoma 33 and glioblastoma multiforme 31, surgically treated for the tumours and followed up for one to sixteen years, were retrospectively analysed for the incidence of pre and postoperative epileptic seizures. 122 patients (61% had seizures preoperatively. 62 (50.8% of them had at least one or more seizures during follow up. Seizures were persistent in 22 patients. Doubtful, or one or two minor seizures occurred in 19 cases. Six patients in this group had seizure only at the time of CT confirmed recurrence, after a seizure free interval of one to nine years. Amongst 78 patients who did not have seizures preoperatively, 24 (30.6% developed seizures during the postoperative follow up period. Recurrent attacks were reported only by 5 patients while 15 patients had seizure(s only at the time of recurrence of tumour. Two patients had a few seizures in the early postoperative period and none thereafter, while doubtful seizures were reported by two patients.

  2. An application of Data Assimilation to a dynamic global vegetation model: fusing CLM(ED) model results with streams of observed data

    Science.gov (United States)

    Massoud, Elias; Xu, Chonggang; Fisher, Rosie; Vrugt, Jasper

    2016-04-01

    We implement a data assimilation approach for a Dynamic Global Vegetation Model (DGVM), named the CLM(ED) for its combined strengths of a Community Land Model (CLM) and an implementation of the Ecosystem Demography (ED) concept. This unique model combination allows for scaling the behavior of forest ecosystems by aggregating individual trees into representative "cohorts", and thus allows for the prediction of plant distribution (including stem distribution, mortality, and growth) directly from their given physiological traits. The model is constantly improving as it evolves, as less simple empirical models are used and more physically based ones are included to represent the physiological and biogeochemical processes taking place on the land-air surface. For example, very recently a mechanistic model simulating the photosynthetic capacity was implemented for a better representation of a leaf's nitrogen allocation. Some possible outputs of CLM(ED) include GPP, NPP, LAI, and interestingly, predictions of biome boundaries. In this study, we first conduct a global sensitivity analysis by estimating the range of model parameters from literature. Then, an application of Data Assimilation (DA) is introduced, where we attempt to fuse the model simulations with observed data, such as GPP. The updated system properties achieved through DA allow for better parameterization and more accurate overall predictions of vegetation dynamics. More importantly, this study addresses structural uncertainties within the model, and by combining model estimates with observed measurements, we aim to improve the overall representation of the underlying processes by explicitly pinpointing deficiencies in the model structure. We advocate the use of DA in Earth System Models for many reasons, including the direct benefit linked to the recent availability of ecological data sets, the efficient implementation within models thanks to improvements in computational power, and the proven ability of DA

  3. Seizures and epilepsy in cats

    OpenAIRE

    Moore SA

    2014-01-01

    Sarah A Moore Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH, USA Abstract: Seizures are a common presenting complaint in cats, although causes and options for the treatment of seizures in this species have been historically poorly described in the veterinary literature. Seizure manifestation in cats may be different than what is typically seen in dogs, but the underlying causes of seizure activity are the same. These include primary epilepsies, structura...

  4. [Dynamics of ultrastructure changes in sheet plate fiber flax with braking transport assimilate by nitrate-anion].

    Science.gov (United States)

    Abdrakhimov, F A; Batasheva, S N; Bakirova, G G; Chikov, V I

    2008-01-01

    Changes in leaf mesophyll cell ultrastructure under nitrate feeding into the apoplast of common flax (Linum usitatissimum L.) in the form of 50 mM KNO3 solution were studied. In 30 min after the beginning of nitrate feeding through the transpiration water stream, swelling of mitochondrial and microbodies, clarification of their matrices, and curling of dictyosome discs into annular structures were observed. These events characterized symplastic domain formed by mesophyll, bundle sheath and phloem parenchyma cells, and were not found in companion cell-sieve element complex. Simultaneously, formation of large central vacuoles in companion cells was noted. Restoration of organelle structures in assimilating cells and phloem parenchyma in 1-2 h after treatment was accompanied by enhancement of morphological changes in phloem elements and companion cells and signs of plasmolysis in the mesophyll cells. It was supposed that the two-phase character of changes in leaf organelle ultrastructure and photosynthesis might reflect duality of leaf cell response to nitrate ion. The rapid alterations of the structure can be coupled with direct influence of the anion on cell metabolism and(or) with signal-regulatory functions of oxidized nitrogen forms, while the slower ones reflect the result of suppression of photoassimilate export from leaves by the anion. PMID:18822790

  5. Seizure prediction and its applications.

    Science.gov (United States)

    Iasemidis, Leon D

    2011-10-01

    Epilepsy is characterized by intermittent, paroxysmal, hypersynchronous electrical activity that may remain localized and/or spread and severely disrupt the brain's normal multitask and multiprocessing function. Epileptic seizures are the hallmarks of such activity. The ability to issue warnings in real time of impending seizures may lead to novel diagnostic tools and treatments for epilepsy. Applications may range from a warning to the patient to avert seizure-associated injuries, to automatic timely administration of an appropriate stimulus. Seizure prediction could become an integral part of the treatment of epilepsy through neuromodulation, especially in the new generation of closed-loop seizure control systems. PMID:21939848

  6. Voltage synchronizations between multichannel electroencephalograms during epileptic seizures

    CERN Document Server

    Tuncay, Caglar

    2010-01-01

    The underlying dynamics for the electroencephalographic (EEG) recordings from humans but especially epilepsy patients are usually not completely known. However, the ictal activity is claimed to be characterized by synchronous oscillations in the brain voltages in the literature. These time dependent interdependencies (synchronization, coupling) between the EEG voltages from epileptogenic and non epileptogenic brain sites of nineteen focal epileptic patients are investigated in this work. It is found that strong synchronizationdesynchronization events occur in alternation during most of the investigated seizures. Thus, these seizures are detected with considerable sensitivity (71 of the 79 seizures).

  7. The ictal wavefront is the spatiotemporal source of discharges during spontaneous human seizures.

    Science.gov (United States)

    Smith, Elliot H; Liou, Jyun-You; Davis, Tyler S; Merricks, Edward M; Kellis, Spencer S; Weiss, Shennan A; Greger, Bradley; House, Paul A; McKhann Ii, Guy M; Goodman, Robert R; Emerson, Ronald G; Bateman, Lisa M; Trevelyan, Andrew J; Schevon, Catherine A

    2016-01-01

    The extensive distribution and simultaneous termination of seizures across cortical areas has led to the hypothesis that seizures are caused by large-scale coordinated networks spanning these areas. This view, however, is difficult to reconcile with most proposed mechanisms of seizure spread and termination, which operate on a cellular scale. We hypothesize that seizures evolve into self-organized structures wherein a small seizing territory projects high-intensity electrical signals over a broad cortical area. Here we investigate human seizures on both small and large electrophysiological scales. We show that the migrating edge of the seizing territory is the source of travelling waves of synaptic activity into adjacent cortical areas. As the seizure progresses, slow dynamics in induced activity from these waves indicate a weakening and eventual failure of their source. These observations support a parsimonious theory for how large-scale evolution and termination of seizures are driven from a small, migrating cortical area. PMID:27020798

  8. The ictal wavefront is the spatiotemporal source of discharges during spontaneous human seizures

    Science.gov (United States)

    Smith, Elliot H.; Liou, Jyun-you; Davis, Tyler S.; Merricks, Edward M.; Kellis, Spencer S.; Weiss, Shennan A.; Greger, Bradley; House, Paul A.; McKhann II, Guy M.; Goodman, Robert R.; Emerson, Ronald G.; Bateman, Lisa M.; Trevelyan, Andrew J.; Schevon, Catherine A.

    2016-01-01

    The extensive distribution and simultaneous termination of seizures across cortical areas has led to the hypothesis that seizures are caused by large-scale coordinated networks spanning these areas. This view, however, is difficult to reconcile with most proposed mechanisms of seizure spread and termination, which operate on a cellular scale. We hypothesize that seizures evolve into self-organized structures wherein a small seizing territory projects high-intensity electrical signals over a broad cortical area. Here we investigate human seizures on both small and large electrophysiological scales. We show that the migrating edge of the seizing territory is the source of travelling waves of synaptic activity into adjacent cortical areas. As the seizure progresses, slow dynamics in induced activity from these waves indicate a weakening and eventual failure of their source. These observations support a parsimonious theory for how large-scale evolution and termination of seizures are driven from a small, migrating cortical area. PMID:27020798

  9. Galactosemia and phantom absence seizures

    OpenAIRE

    Zeynep Aydin-Özemir; Pinar Tektürk; Zehra Oya Uyguner; Betül Baykan

    2014-01-01

    Generalized and focal seizures can rarely be seen in galactosemia patients, but absence seizures were not reported previously. An 18-year-old male was diagnosed as galactosemia at the age of 8 months. No family history of epilepsy was present. His absence seizures realized at the age of 9 years. Generalized 3-4 Hz spike-wave discharges were identified in his electroencephalography. Homozygous mutation at exon 6 c. 563A > G was identified. The electroencephalogram of his sibling was unremarkab...

  10. Seizures induced by playing music.

    Science.gov (United States)

    Sutherling, W W; Hershman, L M; Miller, J Q; Lee, S I

    1980-09-01

    A 67-year-old organist and minister with diabetes mellitus had stereotyped focal seizures of the left lower face, jaw, and neck. Attacks occurred spontaneously or were induced when he played a specific hymn on the organ. The seizures were not induced by reading, singing, hearing, or playing the hymn silently. The patient had interictal weakness of the left lower face and left side of the tongue. Focal seizures were recorded on an electroencephalogram (EEG) at the right temporofrontal area. This patient illustrates partial seizures induced by playing music. PMID:6775246

  11. Seizures and Teens: Using Technology to Develop Seizure Preparedness

    Science.gov (United States)

    Shafer, Patricia O.; Schachter, Steven C.

    2007-01-01

    Most people learn about seizures from their doctors, but others know only what they have seen on television. Unfortunately, visits to doctor's office aren't long enough to learn all that is needed, and often times, doctors and nurses aren't available to teach this information. Seizures are often represented inaccurately and too dramatically on…

  12. Assimilation in multilingual cities

    OpenAIRE

    Ortega, Javier

    2011-01-01

    Using the Public Use Microdata Files of the 2001 and 2006 Canadian Censuses, we study the determinants of the assimilation of language minorities into the city majority language. We show that official minority members (i.e. francophones in English-speaking cities and anglophones in French-speaking cities) assimilate less than the "allophones" (the individuals with a mother tongue other than English or French), and that immigrants generally assimilate less than natives. In addition, the langua...

  13. Detection and Prediction of Epileptic Seizures

    DEFF Research Database (Denmark)

    Duun-Henriksen, Jonas

    monitoring of their brain waves. More specifically, three issues were investigated: The feasibility of automatic seizure prediction, optimization of automatic seizure detection algorithms, and the link between intra- and extracranial EEG. Regarding feasibility of automatic seizure prediction, neither the...

  14. LAUGHING SEIZURES: A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Deb K

    2015-12-01

    Full Text Available BACKGROUND Normal laughter is a human behavioral response to pleasant feeling, whereas pathological laughter is disproportionate to the emotional context. Hypothalamic hamartoma usually presented with laughing seizures. We are presenting a case of laughing seizure with hypothalamic hamartoma detected on MR Imaging in a 21 years female.

  15. Recurrent seizures after lidocaine ingestion.

    Science.gov (United States)

    Aminiahidashti, Hamed; Laali, Abolghasem; Nosrati, Nazanin; Jahani, Fatemeh

    2015-01-01

    Lidocaine has a concentration-dependent effect on seizures. Concentrations above 15 μg/mL frequently result in seizures in laboratory animals and human. We report a case of central nervous system (CNS) lidocaine toxicity and recurrent seizure after erroneous ingestion of lidocaine solution. A 4-year-old boy presented to the Emergency Department of Imam Hospital of Sari in December 2013 due to tonic-clonic generalized seizures approximately 30 min ago. 3 h before seizure, his mother gave him 2 spoons (amount 20-25 cc) lidocaine hydrochloride 2% solution instead of pediatric gripe by mistake. Seizure with generalized tonic-clonic occurred 3 times in home. Neurological examination was essentially unremarkable except for the depressed level of consciousness. Personal and medical history was unremarkable. There was no evidence of intracranial ischemic or hemorrhagic lesions in computed tomography scan. There were no further seizures, the condition of the patient remained stable, and he was discharged 2 days after admission. The use of viscous lidocaine may result in cardiovascular and CNS toxicity, particularly in children. Conservative management is the best option for treatment of lidocaine induced seizure. PMID:25709968

  16. MMR Vaccination and Febrile Seizures

    DEFF Research Database (Denmark)

    Vestergaard, Mogens; Hviid, Anders; Madsen, Kreesten Meldgaard;

    2004-01-01

    CONTEXT: The rate of febrile seizures increases following measles, mumps, and rubella (MMR) vaccination but it is unknown whether the rate varies according to personal or family history of seizures, perinatal factors, or socioeconomic status. Furthermore, little is known about the long-term outcome...

  17. Predicting epileptic seizures in advance.

    Directory of Open Access Journals (Sweden)

    Negin Moghim

    Full Text Available Epilepsy is the second most common neurological disorder, affecting 0.6-0.8% of the world's population. In this neurological disorder, abnormal activity of the brain causes seizures, the nature of which tend to be sudden. Antiepileptic Drugs (AEDs are used as long-term therapeutic solutions that control the condition. Of those treated with AEDs, 35% become resistant to medication. The unpredictable nature of seizures poses risks for the individual with epilepsy. It is clearly desirable to find more effective ways of preventing seizures for such patients. The automatic detection of oncoming seizures, before their actual onset, can facilitate timely intervention and hence minimize these risks. In addition, advance prediction of seizures can enrich our understanding of the epileptic brain. In this study, drawing on the body of work behind automatic seizure detection and prediction from digitised Invasive Electroencephalography (EEG data, a prediction algorithm, ASPPR (Advance Seizure Prediction via Pre-ictal Relabeling, is described. ASPPR facilitates the learning of predictive models targeted at recognizing patterns in EEG activity that are in a specific time window in advance of a seizure. It then exploits advanced machine learning coupled with the design and selection of appropriate features from EEG signals. Results, from evaluating ASPPR independently on 21 different patients, suggest that seizures for many patients can be predicted up to 20 minutes in advance of their onset. Compared to benchmark performance represented by a mean S1-Score (harmonic mean of Sensitivity and Specificity of 90.6% for predicting seizure onset between 0 and 5 minutes in advance, ASPPR achieves mean S1-Scores of: 96.30% for prediction between 1 and 6 minutes in advance, 96.13% for prediction between 8 and 13 minutes in advance, 94.5% for prediction between 14 and 19 minutes in advance, and 94.2% for prediction between 20 and 25 minutes in advance.

  18. On Variational Data Assimilation in Continuous Time

    CERN Document Server

    Bröcker, Jochen

    2010-01-01

    Variational data assimilation in continuous time is revisited. The central techniques applied in this paper are in part adopted from the theory of optimal nonlinear control. Alternatively, the investigated approach can be considered as a continuous time generalisation of what is known as weakly constrained four dimensional variational assimilation (WC--4DVAR) in the geosciences. The technique allows to assimilate trajectories in the case of partial observations and in the presence of model error. Several mathematical aspects of the approach are studied. Computationally, it amounts to solving a two point boundary value problem. For imperfect models, the trade off between small dynamical error (i.e. the trajectory obeys the model dynamics) and small observational error (i.e. the trajectory closely follows the observations) is investigated. For (nearly) perfect models, this trade off turns out to be (nearly) trivial in some sense, yet allowing for some dynamical error is shown to have positive effects even in th...

  19. Using ensemble data assimilation to forecast hydrological flumes

    OpenAIRE

    Amour, I.; Mussa, Z.; Bibov, A.; Kauranne, T.

    2013-01-01

    Data assimilation, commonly used in weather forecasting, means combining a mathematical forecast of a target dynamical system with simultaneous measurements from that system in an optimal fashion. We demonstrate the benefits obtainable from data assimilation with a dam break flume simulation in which a shallow-water equation model is complemented with wave meter measurements. Data assimilation is conducted with a Variational Ensemble Kalman Filter (VEnKF) algorithm. The resu...

  20. An Ensemble Algorithm Based Component for Geomagnetic Data Assimilation

    OpenAIRE

    Zhibin Sun and Weijia Kuang

    2015-01-01

    Geomagnetic data assimilation is one of the most recent developments in geomagnetic studies. It combines geodynamo model outputs and surface geomagnetic observations to provide more accurate estimates of the core dynamic state and provide accurate geomagnetic secular variation forecasting. To facilitate geomagnetic data assimilation studies, we develop a stand-alone data assimilation component for the geomagnetic community. This component is used to calculate the forecast error covariance mat...

  1. NEONATAL SEIZURES: ETIOLOGY AND FREQUENCY

    Directory of Open Access Journals (Sweden)

    F. Eghbalian

    2008-11-01

    Full Text Available ObjectiveThe aim of the present study was to evaluate the etiology and frequency of neonatal seizure in hospitalized neonates.Materials and MethodsIn this descriptive, cross-sectional study, we evaluated 1295 neonates with seizures admitted to neonatal and NICU wards in our center. Data was collected on age, sex, birth weight, serum levels of calcium, glucose, and sodium, CT scan findings, history of maternal opium abuse, blood and cerebrospinal fluid culture, and analyzed using SPSS 13.ResultsOf a total of 1295 patients, 34 (2.62% had seizure. Mean age was 14.03 ± 10.05 days (range, 1 to 29 days; twenty-five (73.5% neonates were boys and 9 (26.5% were girls. Of 34 neonates with neonatal seizures, 12 (35.3%, 11 (32.4%, 9 (26.5%, 7 (20.6%, and 3 (8.8% had hypocalcemia, asphyxia, hypoglycemia, intracranial hemorrhage, and hypernatremia, respectively.Maternal addiction, meningitis, and sepsis were found in 3 (8.8%, 1 (2.9% and 1 (2.9% of neonates, respectively.ConclusionThe incidence rate of neonatal seizure in the neonates in our NICU and neonatal ward was 2.62%. Common causes of seizure in this study included hypocalcemia, asphyxia, hypoglycemia, intracranial hemorrhage, and hypernatremia. Maternal ddiction, meningitis and sepsis had the lowest prevalence.Keywords:Neonate, Seizure, Etiologies.

  2. Cannabidiol Rescues Acute Hepatic Toxicity and Seizure Induced by Cocaine

    Directory of Open Access Journals (Sweden)

    Luciano Rezende Vilela

    2015-01-01

    Full Text Available Cocaine is a commonly abused illicit drug that causes significant morbidity and mortality. The most severe and common complications are seizures, ischemic strokes, myocardial infarction, and acute liver injury. Here, we demonstrated that acute cocaine intoxication promoted seizure along with acute liver damage in mice, with intense inflammatory infiltrate. Considering the protective role of the endocannabinoid system against cell toxicity, we hypothesized that treatment with an anandamide hydrolysis inhibitor, URB597, or with a phytocannabinoid, cannabidiol (CBD, protects against cocaine toxicity. URB597 (1.0 mg/kg abolished cocaine-induced seizure, yet it did not protect against acute liver injury. Using confocal liver intravital microscopy, we observed that CBD (30 mg/kg reduced acute liver inflammation and damage induced by cocaine and prevented associated seizure. Additionally, we showed that previous liver damage induced by another hepatotoxic drug (acetaminophen increased seizure and lethality induced by cocaine intoxication, linking hepatotoxicity to seizure dynamics. These findings suggest that activation of cannabinoid system may have protective actions on both liver and brain induced by cocaine, minimizing inflammatory injury promoted by cocaine, supporting its further clinical application in the treatment of cocaine abuse.

  3. Cannabidiol rescues acute hepatic toxicity and seizure induced by cocaine.

    Science.gov (United States)

    Vilela, Luciano Rezende; Gomides, Lindisley Ferreira; David, Bruna Araújo; Antunes, Maísa Mota; Diniz, Ariane Barros; Moreira, Fabrício de Araújo; Menezes, Gustavo Batista

    2015-01-01

    Cocaine is a commonly abused illicit drug that causes significant morbidity and mortality. The most severe and common complications are seizures, ischemic strokes, myocardial infarction, and acute liver injury. Here, we demonstrated that acute cocaine intoxication promoted seizure along with acute liver damage in mice, with intense inflammatory infiltrate. Considering the protective role of the endocannabinoid system against cell toxicity, we hypothesized that treatment with an anandamide hydrolysis inhibitor, URB597, or with a phytocannabinoid, cannabidiol (CBD), protects against cocaine toxicity. URB597 (1.0 mg/kg) abolished cocaine-induced seizure, yet it did not protect against acute liver injury. Using confocal liver intravital microscopy, we observed that CBD (30 mg/kg) reduced acute liver inflammation and damage induced by cocaine and prevented associated seizure. Additionally, we showed that previous liver damage induced by another hepatotoxic drug (acetaminophen) increased seizure and lethality induced by cocaine intoxication, linking hepatotoxicity to seizure dynamics. These findings suggest that activation of cannabinoid system may have protective actions on both liver and brain induced by cocaine, minimizing inflammatory injury promoted by cocaine, supporting its further clinical application in the treatment of cocaine abuse. PMID:25999668

  4. Wavelet Approximation in Data Assimilation

    Science.gov (United States)

    Tangborn, Andrew; Atlas, Robert (Technical Monitor)

    2002-01-01

    Estimation of the state of the atmosphere with the Kalman filter remains a distant goal because of high computational cost of evolving the error covariance for both linear and nonlinear systems. Wavelet approximation is presented here as a possible solution that efficiently compresses both global and local covariance information. We demonstrate the compression characteristics on the the error correlation field from a global two-dimensional chemical constituent assimilation, and implement an adaptive wavelet approximation scheme on the assimilation of the one-dimensional Burger's equation. In the former problem, we show that 99%, of the error correlation can be represented by just 3% of the wavelet coefficients, with good representation of localized features. In the Burger's equation assimilation, the discrete linearized equations (tangent linear model) and analysis covariance are projected onto a wavelet basis and truncated to just 6%, of the coefficients. A nearly optimal forecast is achieved and we show that errors due to truncation of the dynamics are no greater than the errors due to covariance truncation.

  5. Occipital seizures imitating migraine aura.

    OpenAIRE

    Panayiotopoulos, C P; Sharoqi, I A; Agathonikou, A

    1997-01-01

    Three cases are reported in which symptoms of occipital seizures resembled the visual aura of migraine. Careful recording of the characteristics and timing of such visual effects will often resolve the diagnostic dilemma.

  6. Galactosemia and phantom absence seizures

    Directory of Open Access Journals (Sweden)

    Zeynep Aydin-Özemir

    2014-01-01

    Full Text Available Generalized and focal seizures can rarely be seen in galactosemia patients, but absence seizures were not reported previously. An 18-year-old male was diagnosed as galactosemia at the age of 8 months. No family history of epilepsy was present. His absence seizures realized at the age of 9 years. Generalized 3-4 Hz spike-wave discharges were identified in his electroencephalography. Homozygous mutation at exon 6 c. 563A > G was identified. The electroencephalogram of his sibling was unremarkable. Our aim was to present the long-term follow-up of a patient diagnosed with galactosemia, who had phantom absence seizures and typical 3-4 Hz spike-wave discharges in his electroencephalogram to draw attention to this rare association.

  7. Galactosemia and phantom absence seizures.

    Science.gov (United States)

    Aydin-Özemir, Zeynep; Tektürk, Pınar; Uyguner, Zehra Oya; Baykan, Betül

    2014-01-01

    Generalized and focal seizures can rarely be seen in galactosemia patients, but absence seizures were not reported previously. An 18-year-old male was diagnosed as galactosemia at the age of 8 months. No family history of epilepsy was present. His absence seizures realized at the age of 9 years. Generalized 3-4 Hz spike-wave discharges were identified in his electroencephalography. Homozygous mutation at exon 6 c. 563A > G was identified. The electroencephalogram of his sibling was unremarkable. Our aim was to present the long-term follow-up of a patient diagnosed with galactosemia, who had phantom absence seizures and typical 3-4 Hz spike-wave discharges in his electroencephalogram to draw attention to this rare association. PMID:25624930

  8. The Genetics of Febrile Seizures

    OpenAIRE

    Dipak Ram; Richard Newton

    2016-01-01

    Investigators from Virginia Commonwealth University, Norwegian Center for Epilepsy and University of Southern Denmark carried out twin studies to analyse the genetic influence of developing epilepsy after febrile seizures.

  9. Management of Reflex Anoxic Seizures

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2013-10-01

    Full Text Available Investigators at the Roald Dahl EEG Unit, Alder Hey Children’s NHS Foundation, Liverpool, UK, review the definition, pathophysiology, clinical presentation, and management of reflex anoxic seizures (RAS in children.

  10. Ranolazine overdose-induced seizures.

    Science.gov (United States)

    Akil, Nour; Bottei, Edward; Kamath, Sameer

    2015-12-01

    Ranolazine is a new anti-anginal medication that was approved by the US Food and Drug Administration (FDA) in 2006 for patients with symptomatic chronic angina despite optimized therapy. This paper presents a case report of a fifteen year old male patient admitted to the pediatric intensive care unit after ranolazine overdose ingestion. He had recurrent new onset seizures that are most likely due to ranolazine overdose. Seizures have never been reported with ranolazine use or abuse. PMID:26072257

  11. Data Assimilation in Marine Models

    DEFF Research Database (Denmark)

    Frydendall, Jan

    This thesis consists of six research papers published or submitted for publication in the period 2006-2009 together with a summary report. The main topics of this thesis are nonlinear data assimilation techniques and estimation in dynamical models. The focus has been on the nonlinear filtering te...... for the Fokker-Planck equation on a 2 dimensional flexible mesh system. The report details the construction of the finite element solver and investigates the potential benefits of a parallel FORTRAN implementation through a series of experiments....

  12. Cumulative ozone effect on canopy stomatal resistance and the impact on boundary layer dynamics and CO2 assimilation at the diurnal scale: A case study for grassland in the Netherlands

    Science.gov (United States)

    Super, Ingrid; Vilà-Guerau de Arellano, Jordi; Krol, Maarten C.

    2015-07-01

    Biological, chemical, and dynamical processes occurring at the surface strongly interact at diurnal scales. Therefore, this study examines the seasonal ozone impact on stomatal resistance, surface energy balance, boundary layer dynamics, and CO2 assimilation at this (sub)diurnal scale under changing conditions. We combine a seasonal canopy resistance module with a surface-boundary layer model that solves the diurnal evolution of dynamical and chemical variables in a well-mixed, convective boundary layer. The model is constrained with observations from Cabauw (Netherlands) for the dry year 2003, representing a well-mixed boundary layer at midlatitudes over water-stressed grassland. To quantify the ozone impact, the Cumulative Uptake of Ozone is calculated over a growing season, which gives an estimate of the reduction in stomatal aperture and photosynthesis. From a sensitivity analysis with mixed-layer temperature and soil moisture content we conclude that drought is the dominant factor that determines the surface energy partitioning and limits CO2 assimilation. Although drought causes stomatal closure, the results indicate that ozone damage, nevertheless, occurs. A second sensitivity analysis with CO2 and ozone shows that ozone damage causes an increase in stomatal resistance of up to 40% under high ozone levels and that CO2-induced stomatal closure limits ozone damage. The impact on boundary layer development through the effect of CO2 and ozone on the stomatal resistance is much smaller. At the diurnal scale soil moisture influences the surface energy partitioning, which affects the entrainment of ozone-rich air. Due to ozone damage, the CO2 assimilation flux is reduced by about 15%.

  13. Displacement Data Assimilation

    CERN Document Server

    Rosenthal, W Steven; Mariano, Arthur J; Restrepo, Juan M

    2016-01-01

    We show that modifying a Bayesian data assimilation scheme by incorporating kinematically-consistent displacement corrections produces a scheme that is demonstrably better at estimating partially observed state vectors in a setting where feature information important. While the displacement transformation is not tied to any particular assimilation scheme, here we implement it within an ensemble Kalman Filter and demonstrate its effectiveness in tracking stochastically perturbed vortices.

  14. Assimilative Capacity Revisited

    OpenAIRE

    Cairns, John

    2008-01-01

    Assimilative capacity is the ability of natural systems to assimilate humankind's wastes. Wastes (output) of some species in natural systems are the resources (input) of other species. Before the Industrial Revolution, this concept of input and output held true for human activity, but industrialization created wastes that were qualitatively and quantitatively different from those of natural systems. The unique nature of some persistent wastes that accumulate in organisms over long periods of ...

  15. [Martin Luther's seizure disorder].

    Science.gov (United States)

    Feldmann, H

    1989-01-01

    Martin Luther's diseases are well documented, because he used to discuss them freely in his letters. There is also a wealth of evidence through reports by his friends. Most of his diseases were common and well known to the contemporary physicians, who accordingly interpreted them correctly: bladder stones, chronic constipation, hemorrhoids. Luther's death obviously was due to a coronary thrombosis. During the last 19 years of his life, in addition to these "natural diseases", Luther also suffered from recurring attacks of a peculiar symptomatology. Luther himself and his friends considered these seizures to be no "natural disease", but Satan punching his flesh, and he compared them to St. Paul's disease (2. Cor. 12). The first of these attacks occurred on July 6, 1527, when Luther was 43 years of age. It began with a roaring tinnitus in his left ear, which increased dramatically and seemed to occupy the left half of his head. Then a state of sickness and collapse followed, however, consciousness was retained throughout the whole period. After a night's rest all the symptoms had subsided, except the tinnitus, which, from that day on, continued for all the following years in varying intensity. Similar attacks with increase of the tinnitus and vertigo as the leading symptoms, seized Luther at irregular intervals and distressed him extremely. Former investigators of Luther's diseases interpreted these attacks as manifestations of a psychiatric disorder and a chronic inflammatory disease of the middle ear. The present detailed study reveals that it was a typical case of Menière's disease of the left ear manifesting itself more than 330 years before Menière's classical observation. PMID:2529669

  16. Osthole suppresses seizures in the mouse maximal electroshock seizure model.

    Science.gov (United States)

    Luszczki, Jarogniew J; Andres-Mach, Marta; Cisowski, Wojciech; Mazol, Irena; Glowniak, Kazimierz; Czuczwar, Stanislaw J

    2009-04-01

    The aim of this study was to determine the anticonvulsant effects of osthole {[7-methoxy-8-(3-methyl-2-butenyl)-2H-1-benzopyran-2-one]--a natural coumarin derivative} in the mouse maximal electroshock-induced seizure model. The antiseizure effects of osthole were determined at 15, 30, 60, and 120 min after its systemic (i.p.) administration. Time course of anticonvulsant action of osthole revealed that the natural coumarin derivative produced a clear-cut antielectroshock activity in mice and the experimentally-derived ED(50) values for osthole ranged from 259 to 631 mg/kg. In conclusion, osthole suppresses seizure activity in the mouse maximal electroshock-induced seizure model. It may become a novel treatment option following further investigation in other animal models of epilepsy and preclinical studies. PMID:19236860

  17. A novel genetic programming approach for epileptic seizure detection.

    Science.gov (United States)

    Bhardwaj, Arpit; Tiwari, Aruna; Krishna, Ramesh; Varma, Vishaal

    2016-02-01

    The human brain is a delicate mix of neurons (brain cells), electrical impulses and chemicals, known as neurotransmitters. Any damage has the potential to disrupt the workings of the brain and cause seizures. These epileptic seizures are the manifestations of epilepsy. The electroencephalograph (EEG) signals register average neuronal activity from the cerebral cortex and label changes in activity over large areas. A detailed analysis of these electroencephalograph (EEG) signals provides valuable insights into the mechanisms instigating epileptic disorders. Moreover, the detection of interictal spikes and epileptic seizures in an EEG signal plays an important role in the diagnosis of epilepsy. Automatic seizure detection methods are required, as these epileptic seizures are volatile and unpredictable. This paper deals with an automated detection of epileptic seizures in EEG signals using empirical mode decomposition (EMD) for feature extraction and proposes a novel genetic programming (GP) approach for classifying the EEG signals. Improvements in the standard GP approach are made using a Constructive Genetic Programming (CGP) in which constructive crossover and constructive subtree mutation operators are introduced. A hill climbing search is integrated in crossover and mutation operators to remove the destructive nature of these operators. A new concept of selecting the Globally Prime offspring is also presented to select the best fitness offspring generated during crossover. To decrease the time complexity of GP, a new dynamic fitness value computation (DFVC) is employed to increase the computational speed. We conducted five different sets of experiments to evaluate the performance of the proposed model in the classification of different mixtures of normal, interictal and ictal signals, and the accuracies achieved are outstandingly high. The experimental results are compared with the existing methods on same datasets, and these results affirm the potential use of

  18. Dynamics and Predictability of Tropical Cyclone Genesis Evaluated through a Coupled EnKF and 4DVar Data Assimilation Method during GRIP and PREDICT 2010.

    Science.gov (United States)

    Reyes, A.; Jenkins, G. S.; Poterjoy, J.; Zhang, F.

    2014-12-01

    The genesis of Hurricane Karl (2010) and Tropical Storm Mathew (2010) are examined and compared using a coupled ensemble Kalman filter and four-dimension variational data assimilation method (E4DVar) to assimilate conventional and field campaign observations. This research makes use of dropsonde and sounding observations, which were collected during both the Genesis and Rapid Intensification Processes (GRIP) and the Pre-Depression Investigation of Cloud Systems in the Tropics (PREDICT) field campaigns. E4DVar uses a mix of climatological and flow-dependent background error covariance obtained from ensemble forecasts together with the tangent linear model and its adjoint to perform the four-dimensional data assimilation. As a result, E4DVar analyses are able to capture multi-scale features of the developing disturbances accurately, such as the evolving thermodynamic and kinematic structure of pre-genesis Karl and Mathew. Preliminary diagnostics shows that the genesis of both storms followed a bottom-up process with several mesoscale convective vorticies (MCVs) observed in the pre-genesis stages. To determine the role of these MCVs and to better understand the initial development of the surface cyclone, a two-dimensional spectral decomposition and filtering of model variables, together with a vorticity budget, are performed on high-resolution (1.5 km) simulations of both systems.

  19. A Systematic Appraisal of Neurosurgical Seizure Prophylaxis: Guidance for Critical Care Management.

    Science.gov (United States)

    Turnbull, David; Singatullina, Nataliya; Reilly, Charles

    2016-07-01

    assimilate the applicable literature regarding seizure prophylaxis. The final guidance is a forum upon which further clinical research could evaluate a new seizure prophylaxis paradigm. PMID:26192247

  20. Data assimilation a mathematical introduction

    CERN Document Server

    Law, Kody; Zygalakis, Konstantinos

    2015-01-01

    This book provides a systematic treatment of the mathematical underpinnings of work in data assimilation, covering both theoretical and computational approaches. Specifically the authors develop a unified mathematical framework in which a Bayesian formulation of the problem provides the bedrock for the derivation, development and analysis of algorithms; the many examples used in the text, together with the algorithms which are introduced and discussed, are all illustrated by the MATLAB software detailed in the book and made freely available online. The book is organized into nine chapters: the first contains a brief introduction to the mathematical tools around which the material is organized; the next four are concerned with discrete time dynamical systems and discrete time data; the last four are concerned with continuous time dynamical systems and continuous time data and are organized analogously to the corresponding discrete time chapters. This book is aimed at mathematical researchers interested in a sy...

  1. Explosive Blast Neuropathology and Seizures

    Directory of Open Access Journals (Sweden)

    S. Krisztian eKovacs

    2014-04-01

    Full Text Available Traumatic brain injury (TBI due to explosive blast exposure is a leading combat casualty. It is also implicated as a key contributor to war related mental health diseases. A clinically important consequence of all types of TBI is a high risk for development of seizures and epilepsy. Seizures have been reported in patients who have suffered blast injuries in the Global War on Terror but the exact prevalence is unknown. The occurrence of seizures supports the contention that explosive blast leads to both cellular and structural brain pathology. Unfortunately, the exact mechanism by which explosions cause brain injury is unclear, which complicates development of meaningful therapies and mitigation strategies. To help improve understanding, detailed neuropathological analysis is needed. For this, histopathological techniques are extremely valuable and indispensable. In the following we will review the pathological results, including those from immunohistochemical and special staining approaches, from recent preclinical explosive blast studies.

  2. Risk of Seizure Recurrence with Neurocysticercosis

    OpenAIRE

    J Gordon Millichap

    2002-01-01

    The risk of seizure recurrence after a first seizure due to neurocysticercosis (NC) was evaluated in a prospective study of 77 patients at the School of Medicine and Research Institute, University of Cuenca, Ecuador, and Columbia University, New York.

  3. Optimality in Data Assimilation

    Science.gov (United States)

    Nearing, Grey; Yatheendradas, Soni

    2016-04-01

    It costs a lot more to develop and launch an earth-observing satellite than it does to build a data assimilation system. As such, we propose that it is important to understand the efficiency of our assimilation algorithms at extracting information from remote sensing retrievals. To address this, we propose that it is necessary to adopt completely general definition of "optimality" that explicitly acknowledges all differences between the parametric constraints of our assimilation algorithm (e.g., Gaussianity, partial linearity, Markovian updates) and the true nature of the environmetnal system and observing system. In fact, it is not only possible, but incredibly straightforward, to measure the optimality (in this more general sense) of any data assimilation algorithm as applied to any intended model or natural system. We measure the information content of remote sensing data conditional on the fact that we are already running a model and then measure the actual information extracted by data assimilation. The ratio of the two is an efficiency metric, and optimality is defined as occurring when the data assimilation algorithm is perfectly efficient at extracting information from the retrievals. We measure the information content of the remote sensing data in a way that, unlike triple collocation, does not rely on any a priori presumed relationship (e.g., linear) between the retrieval and the ground truth, however, like triple-collocation, is insensitive to the spatial mismatch between point-based measurements and grid-scale retrievals. This theory and method is therefore suitable for use with both dense and sparse validation networks. Additionally, the method we propose is *constructive* in the sense that it provides guidance on how to improve data assimilation systems. All data assimilation strategies can be reduced to approximations of Bayes' law, and we measure the fractions of total information loss that are due to individual assumptions or approximations in the

  4. Seizures in Corticobasal Degeneration: A Case Report

    OpenAIRE

    Douglas, Vanja C.; DeArmond, Stephen J.; Aminoff, Michael J.; Miller, Bruce L.; Rabinovici, Gil D

    2009-01-01

    Seizures are relatively common in Alzheimer disease (AD) and other neurodegenerative disorders. To our knowledge, however, there have been no reports of seizures associated with corticobasal degeneration (CBD). We describe a patient with brain biopsy features suggestive of CBD whose course was complicated by complex partial seizures with secondary generalization. Thus, the occurrence of seizures in a patient with dementia should not exclude the diagnosis of CBD.

  5. Neonatal Seizures. Advances in Mechanisms and Management.

    OpenAIRE

    Glass, HC

    2013-01-01

    Seizures occur in approximately 1–5 per 1,000 live births, and are among the most common neurologic conditions managed by a neonatal neurocritical care service. There are several, age-specific factors that are particular to the developing brain, which influence excitability and seizure generation, response to medications, and impact of seizures on brain structure and function. Neonatal seizures are often associated with serious underlying brain injury such as hypoxia-ischemia, stroke or hemor...

  6. On Assimilation of English Sounds

    Institute of Scientific and Technical Information of China (English)

    刘恩华

    2015-01-01

    This paper makes a careful study of assimilation in English speaking, meanwhile a systematic knowledge of assimilation wil be helpful for the pronunciations of English learners, facilitate English fluency and improve listening comprehension.

  7. Seizures after stroke : a prospective clinical study.

    Directory of Open Access Journals (Sweden)

    Dhanuka A

    2001-01-01

    Full Text Available Stroke is one of the most common causes of epilepsy in elderly. However, there have been very few prospective studies to define the incidence, pattern and outcome of seizures in stroke. Most studies are based on retrospective analysis of hospital records. Hence, we planned this prospective study to see the clinical, radiological and electroencephalographic characteristics of seizures in stroke and their outcome, from a north Indian tertiary care centre. Over a span of approximately 6 years, 269 consecutive patients with stroke were studied and followed up. Thirty-five (13% of these developed seizures, primarily related to stroke, during mean follow up period of 15.9 months. Twenty of these had infarctions while 15 had haemorrhages. Involvement of the cortical region was seen in most of the patients with seizures. In these patients, 86% of the lesions involved cortical areas exclusively or in addition to subcortical areas on CT scan of the brain. Twenty-seven (77% developed early seizures, two third of them had immediate post-stroke seizures. None of the patients with early onset seizures developed recurrent seizures or epilepsy, while 50% of late onset seizures developed epilepsy. No specific EEG pattern was found in those who later developed epilepsy. In the present study, early onset seizures after stroke were rather common and did not affect outcome and did not recur even when not treated with anti-epileptics. Late onset seizures were less common but were associated with recurrent seizures.

  8. Types of Seizures Affecting Individuals with TSC

    Science.gov (United States)

    ... head from injury. Turn on side to keep airway clear. Reassure when consciousness returns. Time the event If single seizure lasted less than 5 minutes, ask the person if hospital evaluation is wanted. If multiple seizures, or if one seizure lasts ...

  9. SST data assimilation experiments using an adaptive variational method

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An adaptive variational data assimilation method is proposed by Zhu and Kamachi[1]. This method can adaptively adjust the model state without knowing explicitly the model error covariance matrix. The method enables very flexible ways to form some reduced order problems. A proper reduced order problem not only reduces computational burden but also leads to corrections that are more consistent with the model dynamics that trends to produce better forecast. These features make the adaptive variational method a good candidate for SST data assimilation because the model error of an ocean model is usually difficult to estimate. We applied this method to an SST data assimilation problem using the LOTUS data sets and an ocean mixed layer model (Mellor-Yamada level 2.5). Results of assimilation experiments showed good skill of improvement subsurface temperatures by assimilating surface observation alone.

  10. Are Epileptic Seizures Quakes of the Brain? An Approach by Means of Nonextensive Tsallis Statistics

    CERN Document Server

    Eftaxias, K; Athanasopoulou, L; Kalimeri, M; Potirakis, S M; Balasis, G

    2011-01-01

    The field of study of complex systems holds that the dynamics of complex systems are founded on universal principles that may used to describe a great variety of scientific and technological approaches of different types of natural, artificial, and social systems. Authors have suggested that earthquake dynamics and neurodynamics can be analyzed within similar mathematical frameworks, a claim further supported by recent evidence. The purpose of this paper is to suggest a shift in emphasis from the large to the small in the search for a dynamical analogy between seizure and earthquake. Our analyses focus on a single epileptic seizure generation and the activation of a single fault (earthquake) and not on the statistics of sequences of different seizures and earthquakes. A central property of the epileptic seizure / earthquake generation is the occurrence of coherent large-scale collective behaviour with very rich structure, resulting from repeated nonlinear interactions among the constituents of the system, res...

  11. Nonlinear analysis of EEG for epileptic seizures

    Energy Technology Data Exchange (ETDEWEB)

    Hively, L.M.; Clapp, N.E.; Daw, C.S.; Lawkins, W.F. [Oak Ridge National Lab., TN (United States); Eisenstadt, M.L. [Knoxville Neurology Clinic, St. Mary`s Medical Center, Knoxville, TN (United States)

    1995-04-01

    We apply chaotic time series analysis (CTSA) to human electroencephalogram (EEG) data. Three epoches were examined: epileptic seizure, non-seizure, and transition from non-seizure to seizure. The CTSA tools were applied to four forms of these data: raw EEG data (e-data), artifact data (f-data) via application of a quadratic zero-phase filter of the raw data, artifact-filtered data (g- data) and that was the residual after subtracting f-data from e-data, and a low-pass-filtered version (h-data) of g-data. Two different seizures were analyzed for the same patient. Several nonlinear measures uniquely indicate an epileptic seizure in both cases, including an abrupt decrease in the time per wave cycle in f-data, an abrupt increase in the Kolmogorov entropy and in the correlation dimension for e-h data, and an abrupt increase in the correlation dimension for e-h data. The transition from normal to seizure state also is characterized by distinctly different trends in the nonlinear measures for each seizure and may be potential seizure predictors for this patient. Surrogate analysis of e-data shows that statistically significant nonlinear structure is present during the non-seizure, transition , and seizure epoches.

  12. Glycolysis in energy metabolism during seizures

    Institute of Scientific and Technical Information of China (English)

    Heng Yang; Jiongxing Wu; Ren Guo; Yufen Peng; Wen Zheng; Ding Liu; Zhi Song

    2013-01-01

    Studies have shown that glycolysis increases during seizures, and that the glycolytic metabolite lactic acid can be used as an energy source. However, how lactic acid provides energy for seizures and how it can participate in the termination of seizures remains unclear. We reviewed possible mechanisms of glycolysis involved in seizure onset. Results showed that lactic acid was involved in seizure onset and provided energy at early stages. As seizures progress, lactic acid reduces the pH of tissue and induces metabolic acidosis, which terminates the seizure. The specific mechanism of lactic acid-induced acidosis involves several aspects, which include lactic acid-induced inhibition of the glycolytic enzyme 6-diphosphate kinase-1, inhibition of the N-methyl-D-aspartate receptor, activation of the acid-sensitive 1A ion channel, strengthening of the receptive mechanism of the inhibitory neurotransmitter γ-aminobutyric acid, and changes in the intra- and extracellular environment.

  13. Epileptic Seizures in Multiple Sclerosis Patients

    Directory of Open Access Journals (Sweden)

    Kamber Zeqiraj

    2013-06-01

    Full Text Available Objective: The presence of epileptic seizures in patients with multiple sclerosis (MS is a well-known phenomenon. The aims of our study, performed in our clinic are to point out the correlation of the mean age/gender and age of MS patients with the onset of seizures, to identify the types of epileptic seizures in MS patients by sex/age, to identify the correlation between relapses and seizures, and to identify the main electrophysiological / imaging changes. Material and Met-hod: The medical records of 300 MS patients observed between January 2000 and December 2009 in the Neurological Clinic of University Clinical Centre of Kosova were reviewed. All patients fulfilled the McDonald MS criteria Epilepsy diagnosis was based on the ILAE (International League against Epilepsy (1983 criteria while epileptic seizures were classified based on the ILAE classification (1981. Results: Out of 300 MS patients enrolled in this study, 49 (16.33% were identified with seizures or epilepsy. In 23 (47% patients out of 49, seizures or epilepsy appeared after the MS diagnosis. In 6 patients (12.2%, epileptic attacks preceded the MS diagnosis, while in 20 patients (40.8%, epilepsy was diagnosed before multiple sclerosis. These patients were treated with antiepileptics. Out of 23 patients (47% in whom the epileptic seizures appeared after the MS diagnosis, 17 (74% had simple partial seizures, and 6 (26% had complex partial seizures. Based to our study, the epileptic seizures in MS patients appeared about 2.2 years after the MS diagnosis. Discussion: Simple partial seizures were 2.8 times more frequent compared to complex partial seizures. In female patients the prevalence of complex partial seizures was higher than in male patients with multiple sclerosis. (Turkish Journal of Neurology 2013; 19: 40-3

  14. Assimilation in multilingual cities

    OpenAIRE

    Ortega, Javier; Verdugo, Gregory

    2015-01-01

    International audience We characterise how the assimilation patterns of minorities into the strong and the weak language differ in a situation of asymmetric bilingualism. Using large variations in language composition in Canadian cities from the 2001 and 2006 Censuses, we show that the differences in the knowledge of English by immigrant allophones (i.e. the immigrants with a mother tongue other than English and French) in English-majority cities are mainly due to sorting across cities. In...

  15. Assimilation characteristics of vanadium ferroalloys in liquid steel

    International Nuclear Information System (INIS)

    The assimilation characteristics of various vanadium ferroalloys were identified in a ''dynamic way'' using the load cell technique. The ferrovanadium alloys which have a vanadium content less than 68 wt % belong to class 1 ferroalloys. They utilize a melting mechanism during their assimilation in liquid steel. The ferrovanadium alloys which have a vanadium content greater than 68 wt % belong to class 2 ferroalloys. These follow a dissolution mechanism during their assimilation in liquid steel. Their mass transfer kinetics is at least seven times slower than the previously mentioned ferrovanadium alloys

  16. [Recurrent seizures of unknown aetiology].

    Science.gov (United States)

    Krauß, Martha; Berkermann, Heiner; Ghadimi, Michael; Gaedcke, Jochen; Bürger, Tobias

    2016-04-01

    History and admission findings | A 41year old woman presented at our internistic clinic after treatment by an emergency doctor because of confusion and amnesia accompanied by a hypoglycaemic episode while driving her car. Only by giving continuous glucose intravenously a stable clinical state could be achieved. In her medical history she took Lamotrigin for 12 years since she had seizures of unknown aetiology. 16 years ago she had similar sudden attacks with confusion and hypoglycaemia. At that time thorough diagnostics at the clinic for internal medicine did not reveal any evidence for hyperinsulinaemia. While taking Lamotrigin the patient had no seizures or similar symptoms for 12 years. Treatment and course | In the present case we detected a tumor in the pancreas and a two-fold increased insulin secretion. Histopathological work-up of the removed tissue confirmed the suspected diagnosis of insulinoma. Postoperatively, Lamotrigin treatment was terminated. Since then the patient remained asymptomatic. PMID:27123728

  17. A novel seizure detection algorithm informed by hidden Markov model event states

    Science.gov (United States)

    Baldassano, Steven; Wulsin, Drausin; Ung, Hoameng; Blevins, Tyler; Brown, Mesha-Gay; Fox, Emily; Litt, Brian

    2016-06-01

    Objective. Recently the FDA approved the first responsive, closed-loop intracranial device to treat epilepsy. Because these devices must respond within seconds of seizure onset and not miss events, they are tuned to have high sensitivity, leading to frequent false positive stimulations and decreased battery life. In this work, we propose a more robust seizure detection model. Approach. We use a Bayesian nonparametric Markov switching process to parse intracranial EEG (iEEG) data into distinct dynamic event states. Each event state is then modeled as a multidimensional Gaussian distribution to allow for predictive state assignment. By detecting event states highly specific for seizure onset zones, the method can identify precise regions of iEEG data associated with the transition to seizure activity, reducing false positive detections associated with interictal bursts. The seizure detection algorithm was translated to a real-time application and validated in a small pilot study using 391 days of continuous iEEG data from two dogs with naturally occurring, multifocal epilepsy. A feature-based seizure detector modeled after the NeuroPace RNS System was developed as a control. Main results. Our novel seizure detection method demonstrated an improvement in false negative rate (0/55 seizures missed versus 2/55 seizures missed) as well as a significantly reduced false positive rate (0.0012 h versus 0.058 h‑1). All seizures were detected an average of 12.1 ± 6.9 s before the onset of unequivocal epileptic activity (unequivocal epileptic onset (UEO)). Significance. This algorithm represents a computationally inexpensive, individualized, real-time detection method suitable for implantable antiepileptic devices that may considerably reduce false positive rate relative to current industry standards.

  18. Smartphone applications for seizure management.

    Science.gov (United States)

    Pandher, Puneet Singh; Bhullar, Karamdeep Kaur

    2016-06-01

    Technological advancements continue to provide innovative ways of enhancing patient care in medicine. In particular, the growing popularity of smartphone technology has seen the recent emergence of a myriad of healthcare applications (or apps) that promise to help shape the way in which health information is delivered to people worldwide. While limited research already exists on a range of such apps, our study is the first to examine the salient features of smartphone applications as they apply to the area of seizure management. For the purposes of this review, we conducted a search of the official online application stores of the five major smartphone platforms: iPhone, Android, Blackberry, Windows Mobile and Nokia-Symbian. Apps were included if they reported to contain some information or tools relating to seizure management and excluded if they were aimed exclusively at health professionals. A total of 28 applications met these criteria. Overall, we found an increasing number of epilepsy apps available on the smartphone market, but with only a minority offering comprehensive educational information alongside tools such as seizure diaries, medication tracking and/or video recording. PMID:25038202

  19. Autoregressive Models of Background Errors for Chemical Data Assimilation

    OpenAIRE

    Constantinescu, Emil M.; Chai, Tianfeng; Sandu, Adrian; Gregory R. Carmichael

    2006-01-01

    The task of providing an optimal analysis of the state of the atmosphere requires the development of dynamic data-driven systems that efficiently integrate the observational data and the models. Data assimilation (DA) is the process of adjusting the states or parameters of a model in such a way that its outcome (prediction) is close, in some distance metric, to observed (real) states. It is widely accepted that a key ingredient of successful data assimilation is a realistic estimation of th...

  20. Visual reflex seizures induced by complex stimuli.

    Science.gov (United States)

    Zifkin, Benjamin G; Inoue, Yushi

    2004-01-01

    Visual reflex seizures induced by complex stimuli may be triggered by patterned and flashing displays that are now ubiquitous. The seizures may be clinically generalized, but unilateral and bilateral myoclonic attacks also may be triggered, especially in patients with juvenile myoclonic epilepsy, and recently, clearly focal reflex occipital lobe seizures have been described. Some seizure-triggering properties of video displays can be identified, such as perceived brightness, pattern, flicker frequency, and color. Knowledge of these is useful in planning individual treatment and in designing regulations for screen content of television broadcasts or for other video displays. Some subjects will also be sensitive to cognitive or action-programming activation, especially when playing video games, and this can increase the chance of seizure triggering. Nonspecific factors such as sleep deprivation, prolonged exposure, and drug or alcohol use also may play a role in reflex seizure occurrence. PMID:14706042

  1. EPSP depression following neocortical seizures in cat.

    Science.gov (United States)

    Nita, Dragos A; Cissé, Youssouf; Timofeev, Igor

    2008-04-01

    To study the possible mechanism(s) underlying unresponsiveness following neocortical seizures, we recorded excitatory postsynaptic potentials (EPSPs) of cortical neurons evoked by ipsilateral cortical stimulation before and after spontaneous or elicited seizures. Regular-spiking neurons (n = 32) were intracellularly recorded in association area five of cats under ketamine-xylazine or barbiturate anesthesia. Compared with control responses, cortically evoked EPSPs were characterized by decreased amplitude after electrographic seizures. Synaptic responses and intrinsic properties were measured by applying extracellular electrical stimuli followed by intracellular hyperpolarizing current pulses. The input resistance decreased during seizures but quickly recovered to control level after the paroxysms, whereas the amplitude of evoked EPSPs remained lower following seizures, generally for 2-12 min, suggesting that the decreased EPSPs were not due to an alteration of intrinsic response. Data demonstrate a long-lasting decreased synaptic responsiveness following generalized spike-wave seizures slowly recovering in time. PMID:18031546

  2. Channel selection for automatic seizure detection

    DEFF Research Database (Denmark)

    Duun-Henriksen, Jonas; Kjaer, Troels Wesenberg; Madsen, Rasmus Elsborg; Remvig, Line Sofie; Thomsen, Carsten Eckhart; Sørensen, Helge Bjarup Dissing

    2012-01-01

    Objective: To investigate the performance of epileptic seizure detection using only a few of the recorded EEG channels and the ability of software to select these channels compared with a neurophysiologist. Methods: Fifty-nine seizures and 1419 h of interictal EEG are used for training and testing...... of an automatic channel selection method. The characteristics of the seizures are extracted by the use of a wavelet analysis and classified by a support vector machine. The best channel selection method is based upon maximum variance during the seizure. Results: Using only three channels, a seizure...... recorded directly on the epileptic focus. Conclusions: Based on our dataset, automatic seizure detection can be done using only three EEG channels without loss of performance. These channels should be selected based on maximum variance and not, as often done, using the focal channels. Significance: With...

  3. Data assimilation in hydrological modelling

    OpenAIRE

    Drecourt, Jean-Philippe; Rosbjerg, Dan

    2004-01-01

    Data assimilation is an invaluable tool in hydrological modelling as it allows to efficiently combine scarce data with a numerical model to obtain improved model predictions. In addition, data assimilation also provides an uncertainty analysis of the predictions made by the hydrological model. In this thesis, the Kalman filter is used for data assimilation with a focus on groundwater modelling. However the developed techniques are general and can be applied also in other modelling domains. Mo...

  4. Assimilation: central and peripheral effects

    OpenAIRE

    Weert, C.M.M. de; Kruysbergen, N.A.W.H. van

    1997-01-01

    Assimilation and contrast have opposite effects: Contrast leads to an increase of perceived differences between neighbouring fields, whereas assimilation leads to a reduction. It is relatively easy to demonstrate these effects, but the precise localisation of these effects in the perceptual system is not yet possible. In an experiment the strength of assimilation effects was modified by adding spatial noise. By varying the localisation in perceived space of the added noise (by presentation of...

  5. Moxifloxacin Induced Seizures -A Case Report

    OpenAIRE

    Jiana Shi; Huimin Xu

    2014-01-01

    Abstract A 73-year-old female patient developed a generalized tonic-clonic seizure on the 6th day after treatment with moxifloxacin 400 mg daily intravenously for appendicitis. This patient had atrial fibrillation and history of a surgery for intracerebral hemorrhage, with impaired renal function and liver function, but without history of seizures. Moxifloxacin was discontinued and switched to cefuroxime. The patient remained seizure-free at discharge four days later. The naranjo adverse drug...

  6. Seizures and X-linked intellectual disability

    OpenAIRE

    Stevenson, Roger E.; Holden, Kenton R; Rogers, R. Curtis; Schwartz, Charles E

    2012-01-01

    Intellectual disability occurs as an isolated X-linked trait and as a component of recognizable X-linked syndromes in the company of somatic, metabolic, neuromuscular, or behavioral abnormalities. Seizures accompany intellectual disability in almost half of these X-linked disorders. The spectrum of seizures found in the X-linked intellectual disability syndromes is broad, varying in time of onset, type of seizure, and response to anticonvulsant therapy. The majority of the genes associated wi...

  7. Breakthrough seizures after starting vilazodone for depression.

    Science.gov (United States)

    McKean, James; Watts, Hannah; Mokszycki, Robert

    2015-03-01

    Vilazodone is a new selective serotonin reuptake inhibitor (SSRI) and serotonin 5-HT1a partial agonist that is approved by the United States Food and Drug Administration to treat major depression. SSRI-induced seizures are rare and are more likely to be associated with larger doses and severe symptoms such as those present in serotonin syndrome. Several case reports have implicated SSRIs, buspirone, or the combination of these agents as the cause of seizures, but these reports were confounded with either coingestions or doses that exceeded FDA recommendations. We describe a 22-year-old woman with a history of seizure disorder who had been seizure free for the previous 8 years and experienced two breakthrough seizures shortly after starting vilazodone. Her dose of vilazodone had recently been titrated to 40 mg/day when she experienced the first seizure. She was instructed to taper vilazodone over the next several days, then discontinue the drug, and then follow up with her neurologist. Based on the patient's history, physical examination, and recent dose increase, it was plausible that vilazodone was the cause of the seizures. Use of the Naranjo adverse drug reaction probability scale indicated a possible relationship (score of 4) between her development of seizures and vilazodone therapy. The pharmacodynamics of this particular class of SSRI has both proconvulsive and anticonvulsive mechanisms. This is of particular concern in patients with a history of seizure disorder who are starting antidepressive therapy. In persons with epilepsy who are taking vilazodone and experience breakthrough seizures, practitioners should consider this drug as a potential cause of these seizures. Thus, until future research and experience with vilazodone can provide a definitive answer, clinicians should be cautious when prescribing this medication to treat depression in patients with a history of seizure disorder. PMID:25809181

  8. Orgasm Induced Seizures: A Rare Phenomenon.

    Science.gov (United States)

    Chaukimath, S P; Patil, P S

    2015-01-01

    A variety of stimuli can cause reflex seizures, Some triggers include light, music and cognitive phenomenon. There are case reports however where the phenomenon of sexual activity has been a trigger for epileptic seizures. Most of these cases reported are in women so far, and were found to be localized to right cerebral hemisphere. We report a case of a 36-year-old male with orgasm-induced seizures, with other atypical features compared to majority of previous reports. PMID:27057393

  9. Integrated Data Assimilation Architecture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Integrated Data Assimilation Architecture (IDAA) addresses the fundamental problem of command, control, and communications systems interoperability....

  10. Integrated Data Assimilation Architecture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Integrated Data Assimilation Architecture (IDAA) is a middleware architecture that facilitates the incorporation of heterogeneous sensing and control devices...

  11. Dynamical Downscaling of Climate Change Impacts on Wind Energy Resources in the Contiguous United States by Using a Limited-Area Model with Scale-Selective Data Assimilation

    Directory of Open Access Journals (Sweden)

    Bin Liu

    2014-01-01

    Full Text Available By using a limited-area model (LAM in combination with the scale-selective data assimilation (SSDA approach, wind energy resources in the contiguous United States (CONUS were downscaled from IPCC CCSM3 global model projections for both current and future climate conditions. An assessment of climate change impacts on wind energy resources in the CONUS region was then conducted. Based on the downscaling results, when projecting into future climate under IPCC’s A1B scenario, the average annual wind speed experiences an overall shift across the CONUS region. From the current climate to the 2040s, the average annual wind speed is expected to increase from 0.1 to 0.2 m s−1 over the Great Plains, Northern Great Lakes Region, and Southwestern United States located southwest of the Rocky Mountains. When projecting into the 2090s from current climate, there is an overall increase in the Great Plains Region and Southwestern United States located southwest of the Rockies with a mean wind speed increase between 0 and 0.1 m s−1, while, the Northern Great Lakes Region experiences an even greater increase from current climate to 2090s than over the first few decades with an increase of mean wind speed from 0.1 to 0.4 m s−1.

  12. Mesospheric Precursors to the Major Stratospheric Sudden Warming of 2009: Validation and Dynamical Attribution using a Ground-to-Edge-of-Space Data Assimilation System

    Directory of Open Access Journals (Sweden)

    Lawrence Coy

    2011-10-01

    Full Text Available Global meteorological analyses from an assimilation of operational and research observations spanning the ~0-90~km altitude range confirm earlier tentative suggestions that high-altitude winds throughout the upper mesosphere reversed a week before the major stratospheric sudden warming (SSW of January 2009. Analyzed winds reveal descent of mean easterlies from the upper mesosphere to the lower stratosphere, followed by more easterly winds throughout the Arctic troposphere in the weeks after the SSW, indicating that these descending Northern Annular Mode (NAM anomalies reached the surface.  Eliassen-Palm fluxes reveal that the mesospheric precursor to this event was driven by transient nonstationary wave-2 planetary waves that propagated rapidly from the troposphere into the upper mesosphere, where they dissipated and produced easterly mean-flow accelerations.  This early SSW phase was characterized by both descending mesospheric easterlies and poleward expansion of subtropical stratospheric easterlies, which eventually merged in the extratropical upper stratosphere. These wind structures may in turn have focused transient wave-2 PW activity emerging from the troposphere in ways that intensified the SSW.

  13. Regional Ocean Data Assimilation

    Science.gov (United States)

    Edwards, Christopher A.; Moore, Andrew M.; Hoteit, Ibrahim; Cornuelle, Bruce D.

    2015-01-01

    This article reviews the past 15 years of developments in regional ocean data assimilation. A variety of scientific, management, and safety-related objectives motivate marine scientists to characterize many ocean environments, including coastal regions. As in weather prediction, the accurate representation of physical, chemical, and/or biological properties in the ocean is challenging. Models and observations alone provide imperfect representations of the ocean state, but together they can offer improved estimates. Variational and sequential methods are among the most widely used in regional ocean systems, and there have been exciting recent advances in ensemble and four-dimensional variational approaches. These techniques are increasingly being tested and adapted for biogeochemical applications.

  14. Regional Ocean Data Assimilation

    KAUST Repository

    Edwards, Christopher A.

    2015-01-03

    This article reviews the past 15 years of developments in regional ocean data assimilation. A variety of scientific, management, and safety-related objectives motivate marine scientists to characterize many ocean environments, including coastal regions. As in weather prediction, the accurate representation of physical, chemical, and/or biological properties in the ocean is challenging. Models and observations alone provide imperfect representations of the ocean state, but together they can offer improved estimates. Variational and sequential methods are among the most widely used in regional ocean systems, and there have been exciting recent advances in ensemble and four-dimensional variational approaches. These techniques are increasingly being tested and adapted for biogeochemical applications.

  15. Epileptic Seizures in Multiple Sclerosis Patients

    OpenAIRE

    Kamber Zeqiraj; Nexhat Shatri; Jera Kruja; Afrim Blyta; Enver Isaku; Nazim Dakaj

    2013-01-01

    Objective: The presence of epileptic seizures in patients with multiple sclerosis (MS) is a well-known phenomenon. The aims of our study, performed in our clinic are to point out the correlation of the mean age/gender and age of MS patients with the onset of seizures, to identify the types of epileptic seizures in MS patients by sex/age, to identify the correlation between relapses and seizures, and to identify the main electrophysiological / imaging changes. Material and Met-hod: The medi...

  16. Effective actions for statistical data assimilation

    International Nuclear Information System (INIS)

    Data assimilation is a problem in estimating the fixed parameters and state of a model of an observed dynamical system as it receives inputs from measurements passing information to the model. Using methods developed in statistical physics, we present effective actions and equations of motion for the mean orbits associated with the temporal development of a dynamical model when it has errors, there is uncertainty in its initial state, and it receives information from noisy measurements. If there are statistical dependences among errors in the measurements they can be included in this approach.

  17. Middle Atmosphere Transport Properties of Assimilated Datasets

    Science.gov (United States)

    Pawson, Steven; Rood, Richard

    1999-01-01

    One of the most compelling reasons for performing data assimilation in the middle atmosphere is to obtain global, balanced datasets for studies of trace gas transport and chemistry. This is a major motivation behind the Goddard Earth observation System-Data Assimilation System (GEOS-DAS). Previous studies have shown that while this and other data assimilation systems can generally obtain good estimates of the extratropical rotational velocity field, the divergent part of the dynamical field is deficient; this impacts the "residual circulation" and leads to spurious trace gas transport on seasonal and interannual timescales. These problems are impacted by the quality and the method of use of the observational data and by deficiencies in the atmospheric general circulation model. Whichever the cause at any place and time, the "solution" is to introduce non-physical forcing terms into the system (the so-called incremental analysis updates); these can directly (thermal) or indirectly (mechanical) affect the residual circulation. This paper will illustrate how the divergent circulation is affected by deficiencies in both observations and models. Theoretical considerations will be illustrated with examples from the GEOS-DAS and from simplified numerical experiments. These are designed to isolate known problems, such as the inability of models to sustain a quasi-biennial oscillation and sparse observational constraints on tropical dynamics, or radiative inconsistencies in the presence of volcanic aerosols.

  18. Middle Atmospheric Transport Properties of Assimilated Datasets

    Science.gov (United States)

    Pawson, Steven; Rood, Richard

    1999-01-01

    One of the most compelling reasons for performing data assimilation in the middle atmosphere is to obtain global, balanced datasets for studies of trace gas transport and chemistry. This is a major motivation behind the Goddard Earth observation System-Data Assimilation System (GEOS-DAS). Previous studies have shown that while this and other data assimilation systems can generally obtain good estimates of the extratropical rotational velocity field, the divergent part of the dynamical field is deficient; this impacts the "residual circulation" and leads to spurious trace gas transport on seasonal and interannual timescales. These problems are impacted by the quality and the method of use of the observational data and by deficiencies in the atmospheric general circulation model. Whichever the cause at any place and time, the "solution" is to introduce non-physical forcing terms into the system (the so-called incremental analysis updates); these can directly (thermal) or indirectly (mechanical) affect the residual circulation. This paper will illustrate how the divergent circulation is affected by deficiencies in both observations and models. Theoretical considerations will be illustrated with examples from the GEOS-DAS and from simplified numerical experiments. These are designed to isolate known problems, such as the inability of models to sustain a quasi-biennial oscillation and sparse observational constraints on tropical dynamics, or radiative inconsistencies in the presence of volcanic aerosols.

  19. Probabilistic forecasting and Bayesian data assimilation

    CERN Document Server

    Reich, Sebastian

    2015-01-01

    In this book the authors describe the principles and methods behind probabilistic forecasting and Bayesian data assimilation. Instead of focusing on particular application areas, the authors adopt a general dynamical systems approach, with a profusion of low-dimensional, discrete-time numerical examples designed to build intuition about the subject. Part I explains the mathematical framework of ensemble-based probabilistic forecasting and uncertainty quantification. Part II is devoted to Bayesian filtering algorithms, from classical data assimilation algorithms such as the Kalman filter, variational techniques, and sequential Monte Carlo methods, through to more recent developments such as the ensemble Kalman filter and ensemble transform filters. The McKean approach to sequential filtering in combination with coupling of measures serves as a unifying mathematical framework throughout Part II. Assuming only some basic familiarity with probability, this book is an ideal introduction for graduate students in ap...

  20. Assimilate Partitioning and Plant Development

    Institute of Scientific and Technical Information of China (English)

    Yong-Ling Ruan; John W.Patrick; Hans Weber

    2010-01-01

    @@ It has been a pleasure to organize this special issue of Molecular Plant on 'Assimilate Partitioning and Plant Development'. Assimilate, a collective term describing organic carbon (C) and nitrogen (N), is of paramount importance for plant development and realization of crop productivity.

  1. Data assimilation in hydrological modelling

    DEFF Research Database (Denmark)

    Drecourt, Jean-Philippe

    Data assimilation is an invaluable tool in hydrological modelling as it allows to efficiently combine scarce data with a numerical model to obtain improved model predictions. In addition, data assimilation also provides an uncertainty analysis of the predictions made by the hydrological model. In...

  2. Stability and task complexity: a neural network model of genetic assimilation

    OpenAIRE

    Watson, J.; Geard, N; Wiles, J

    2002-01-01

    Since Hinton and Nowlan introduced the Baldwin effect to the evolutionary computation community, agent-based studies of genetic assimilation have uncovered many details of the dynamic processes involved. In a previous paper, we demonstrated genetic assimilation with a simple food/toxin discrimination task using neural network agents that could evolve their learning rate. The study reported in this paper investigated the genetic assimilation of more complex learning tasks. Kauffman's NK landsc...

  3. The HBM-PDAF assimilation system for operational forecasts in the North and Baltic Seas

    OpenAIRE

    Nerger, Lars; Loza, Svetlana; Brüning, Thorger; Janssen, Frank

    2014-01-01

    To improve hydrographic forecasts in the North and Baltic Seas, the HIROMB-BOOS Model (HBM) has been coupled with the Parallel Data Assimilation Framework PDAF (http://pdaf.awi.de). The forecast system assimilates satellite sea surface temperature as well as in situ data of temperature and salinity profiles to initialize forecasts up to 5 days. The assimilation uses a fully-featured ensemble Kalman filter, which dynamically estimates the uncertainty of the state estimate with an ensemble mode...

  4. Effect of Seizure Clustering on Epilepsy Outcome

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2008-05-01

    Full Text Available A prospective, long-term population-based study was performed to determine whether seizure clustering (3 or more afebrile seizures during a 24 hour period is associated with drug resistance and increased mortality in childhood-onset epilepsy, in a study at University of Turku, Finland, and the Epilepsy Research Group, Berlin, Germany.

  5. Risk of Seizure Recurrence with Neurocysticercosis

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2002-12-01

    Full Text Available The risk of seizure recurrence after a first seizure due to neurocysticercosis (NC was evaluated in a prospective study of 77 patients at the School of Medicine and Research Institute, University of Cuenca, Ecuador, and Columbia University, New York.

  6. Occipital seizures presenting with bilateral visual loss

    OpenAIRE

    Hadjikoutis S; Sawhney I

    2003-01-01

    Transient visual loss may occur with occipital seizures as an ictal or post-ictal phenomenon. Its duration varies from less than one minute to days, or can be permanent. We describe a 61-year-old man presenting with headache, vomiting and bilateral visual loss. EEG revealed persistent spike discharge in the occipital lobes suggesting occipital seizures. His vision improved with carbamazepine.

  7. Diagnosing Functional Seizures in Children and Adolescent

    DEFF Research Database (Denmark)

    Wichaidit, Bianca Taaning; Rask, Charlotte Ulrikka; Ostergaard, John R

    2014-01-01

    Functional seizures (FS) is a condition where the child experiences seizure-like events, without abnormal electrical discharge as measured by EEG, and with high risk of misdiagnosis. Diagnosing FS contains: 1) video-EEG, 2) anamnestic evaluation, focusing on the presence of psychosocial stressors...

  8. ROLE OF MRI IN EVALUATION OF SEIZURES

    Directory of Open Access Journals (Sweden)

    Avadhesh Pratap Singh

    2015-12-01

    Full Text Available BACKGROUND Seizure is a paroxysmal alteration in neurologic function resulting from abnormal excessive neuronal electrical activity. Epilepsy is a chronic condition characterized by recurrent seizures unprovoked by an acute systemic or neurologic insult.1 An epileptic seizure is a clinical manifestation of abnormal, excessive neuronal activity arising in the grey matter of the cerebral cortex. MATERIALS AND METHODS Prospective studies of 100 patients with clinical impression of seizures were examined by 1.5 Tesla magnetic resonance imaging. RESULT A total of 100 patients satisfying the inclusion criteria were included in the study. The age range of patients was from neonate to elderly with male predominance, male 64 (64% and female 36 (36%. GTCS was the most common clinical diagnosis constituting (80% cases. The common abnormalities were cerebral infarction with gliosis (16%, infections – NCC (7% and tuberculoma (10%, cerebral atrophy (1%, developmental cortical malformations (2%, venous thrombosis (4%, low-grade glioma (9%, meningioma (3%. CONCLUSION MRI is the investigation of choice in patients with seizure disorder. The sensitivity of MRI in detecting abnormalities in patients with seizure disorder is in part associated to the underlying pathologies and by the MRI techniques and experience of the interpreting physician. Accurate diagnosis of the cause of seizure is crucial for finding an effective treatment. With its high spatial resolution, excellent inherent soft tissue contrast, multiplanar imaging capability and lack of ionizing radiation, MR imaging has emerged as a versatile tool in the evaluation of patients with seizure disorder.

  9. Seizures and Epilepsy: Hope through Research

    Science.gov (United States)

    ... control with their medication. Seizure triggers include alcohol consumption or alcohol withdrawal, dehydration or missing meals, stress, ... treatment of epilepsy was approved by the U.S. Food and Drug Administration ... stimulation or a fast-acting drug to prevent the seizure from occurring. ...

  10. Seizure phenotypes, periodicity, and sleep-wake pattern of seizures in Kcna-1 null mice.

    Science.gov (United States)

    Wright, Samantha; Wallace, Eli; Hwang, Youngdeok; Maganti, Rama

    2016-02-01

    This study was undertaken to describe seizure phenotypes, natural progression, sleep-wake patterns, as well as periodicity of seizures in Kcna-1 null mutant mice. These mice were implanted with epidural electroencephalography (EEG) and electromyography (EMG) electrodes, and simultaneous video-EEG recordings were obtained while animals were individually housed under either diurnal (LD) condition or constant darkness (DD) over ten days of recording. The video-EEG data were analyzed to identify electrographic and behavioral phenotypes and natural progression and to examine the periodicity of seizures. Sleep-wake patterns were analyzed to understand the distribution and onset of seizures across the sleep-wake cycle. Four electrographically and behaviorally distinct seizure types were observed. Regardless of lighting condition that animals were housed in, Kcna-1 null mice initially expressed only a few of the most severe seizure types that progressively increased in frequency and decreased in seizure severity. In addition, a circadian periodicity was noted, with seizures peaking in the first 12h of the Zeitgeber time (ZT) cycle, regardless of lighting conditions. Interestingly, seizure onset differed between lighting conditions where more seizures arose out of sleep in LD conditions, whereas under DD conditions, the majority occurred out of the wakeful state. We suggest that this model be used to understand the circadian pattern of seizures as well as the pathophysiological implications of sleep and circadian disturbances in limbic epilepsies. PMID:26724401

  11. Seizure detection algorithms based on EMG signals

    DEFF Research Database (Denmark)

    Conradsen, Isa

    Background: the currently used non-invasive seizure detection methods are not reliable. Muscle fibers are directly connected to the nerves, whereby electric signals are generated during activity. Therefore, an alarm system on electromyography (EMG) signals is a theoretical possibility. Objective......: to show whether medical signal processing of EMG data is feasible for detection of epileptic seizures. Methods: EMG signals during generalised seizures were recorded from 3 patients (with 20 seizures in total). Two possible medical signal processing algorithms were tested. The first algorithm was...... patients, while the frequency-based algorithm was efficient for detecting the seizures in the third patient. Conclusion: Our results suggest that EMG signals could be used to develop an automatic seizuredetection system. However, different patients might require different types of algorithms /approaches....

  12. Febrile seizures and risk of schizophrenia

    DEFF Research Database (Denmark)

    Vestergaard, Mogens; Pedersen, Carsten Bøcker; Christensen, Jakob;

    2005-01-01

    BACKGROUND: Febrile seizure is a benign condition for most children, but experiments in animals and neuroimaging studies in humans suggest that some febrile seizures may damage the hippocampus, a brain area of possible importance in schizophrenia. METHODS: A population-based cohort of all children...... with schizophrenia. A history of febrile seizures was associated with a 44% increased risk of schizophrenia [relative risk (RR)=1.44; 95% confidence interval (CI), 1.07-1.95] after adjusting for confounding factors. The association between febrile seizures and schizophrenia remained virtually unchanged when...... restricting the analyses to people with no history of epilepsy. A history of both febrile seizures and epilepsy was associated with a 204% increased risk of schizophrenia (RR=3.04; 95% CI, 1.36-6.79) as compared with people with no such history. CONCLUSIONS: We found a slightly increased risk of schizophrenia...

  13. Moxifloxacin Induced Seizures -A Case Report.

    Directory of Open Access Journals (Sweden)

    Jiana Shi

    2014-09-01

    Full Text Available A 73-year-old female patient developed a generalized tonic-clonic seizure on the 6th day after treatment with moxifloxacin 400 mg daily intravenously for appendicitis. This patient had atrial fibrillation and history of a surgery for intracerebral hemorrhage, with impaired renal function and liver function, but without history of seizures. Moxifloxacin was discontinued and switched to cefuroxime. The patient remained seizure-free at discharge four days later. The naranjo adverse drug reaction probability scale score was 4, indicating a possible adverse reaction to moxifloxacin. The potential risk factors related to moxifloxacin-induced seizures are discussed. It highlights that preexisting central nervous system disease, elderly female with lower bodyweight and severe renal impairment may be the risk factors involved in moxifloxacin-induced seizures.

  14. Spatial Assimilation in Denmark?

    DEFF Research Database (Denmark)

    Andersen, Hans Skifter

    2010-01-01

    In most European countries ethnic minorities have had a tendency to settle in certain parts of cities, and often in social housing, together with other immigrants in so-called multiethnic neighbourhoods. An explanation for this could be low income combined with lack of knowledge of the housing...... market and discrimination, which limits the housing possibilities for ethnic minorities. Another explanation could be that immigrants for different reasons choose to settle in so-called ethnic enclaves where they can find an ethnic social network, which can support them in their new country. In...... traditional research literature about immigration it has been shown that for many immigrants living in enclaves has been a temporary situation. The 'spatial assimilation theory' says that this situation ends when the family has become more integrated in the new society and then moves to other parts of the...

  15. Nonlinear data assimilation

    CERN Document Server

    Van Leeuwen, Peter Jan; Reich, Sebastian

    2015-01-01

    This book contains two review articles on nonlinear data assimilation that deal with closely related topics but were written and can be read independently. Both contributions focus on so-called particle filters. The first contribution by Jan van Leeuwen focuses on the potential of proposal densities. It discusses the issues with present-day particle filters and explorers new ideas for proposal densities to solve them, converging to particle filters that work well in systems of any dimension, closing the contribution with a high-dimensional example. The second contribution by Cheng and Reich discusses a unified framework for ensemble-transform particle filters. This allows one to bridge successful ensemble Kalman filters with fully nonlinear particle filters, and allows a proper introduction of localization in particle filters, which has been lacking up to now.

  16. The Life Time Prevalence of Childhood Seizure

    Directory of Open Access Journals (Sweden)

    P AlizadehTaheri

    2009-03-01

    Full Text Available "nBackground: Seizure is the most common pediatric neurologic disorder. Epidemiological studies of childhood epilepsy are of importance to compare incidence and prevalence rates, age distribution, inheritance, seizure types, epilepsy syn­dromes and treatment strategies. Since there is little information about prevalence of childhood seizure in Iran, this study was aimed to determine the life time prevalence of childhood seizure and some of its determining factors in Tehran, Iran."nMethods: In this cross sectional study, 2500 male and female students, aged 12 years or younger, studying in fifth grade of primary schools in district one of Ministry of Education were assessed by filling a preliminary questionnaire. Those who were categorized by the author as having a history of any form of seizure were assessed by a second questionnaire. The clinical form of seizure, the presumptive cause, positive family history and use of anti-convulsant drugs were recorded."nResults: The life time prevalence of seizure was 32/1000 population which was more prevalent in boys .Generalized seizure was the most common clinical form. Approximately 60% of cases reported febrile convulsion as the presumptive cause stated by the physician. Positive family history was reported in 29.6% of cases. Anti epileptic drugs were taken by 54% of students with a positive history of seizure."nConclusion: The results of this study show that the life time prevalence of seizure is relatively high in Iranian community, although the other factors were in concordance with other communities.

  17. Randomized, controlled trial of ibuprofen syrup administered during febrile illnesses to prevent febrile seizure recurrences

    NARCIS (Netherlands)

    M. van Stuijvenberg (Margriet); G. Derksen-Lubsen (Gerarda); E.W. Steyerberg (Ewout); J.D.F. Habbema (Dik); H.A. Moll (Henriëtte)

    1998-01-01

    textabstractOBJECTIVES: Febrile seizures recur frequently. Factors increasing the risk of febrile seizure recurrence include young age at onset, family history of febrile seizures, previous recurrent febrile seizures, time lapse since previous seizure <6 months, relativ

  18. Data assimilation and model evaluation experiment datasets

    Science.gov (United States)

    Lai, Chung-Cheng A.; Qian, Wen; Glenn, Scott M.

    1994-01-01

    The Institute for Naval Oceanography, in cooperation with Naval Research Laboratories and universities, executed the Data Assimilation and Model Evaluation Experiment (DAMEE) for the Gulf Stream region during fiscal years 1991-1993. Enormous effort has gone into the preparation of several high-quality and consistent datasets for model initialization and verification. This paper describes the preparation process, the temporal and spatial scopes, the contents, the structure, etc., of these datasets. The goal of DAMEE and the need of data for the four phases of experiment are briefly stated. The preparation of DAMEE datasets consisted of a series of processes: (1) collection of observational data; (2) analysis and interpretation; (3) interpolation using the Optimum Thermal Interpolation System package; (4) quality control and re-analysis; and (5) data archiving and software documentation. The data products from these processes included a time series of 3D fields of temperature and salinity, 2D fields of surface dynamic height and mixed-layer depth, analysis of the Gulf Stream and rings system, and bathythermograph profiles. To date, these are the most detailed and high-quality data for mesoscale ocean modeling, data assimilation, and forecasting research. Feedback from ocean modeling groups who tested this data was incorporated into its refinement. Suggestions for DAMEE data usages include (1) ocean modeling and data assimilation studies, (2) diagnosis and theoretical studies, and (3) comparisons with locally detailed observations.

  19. A multimodel data assimilation framework via the ensemble Kalman filter

    Science.gov (United States)

    Xue, Liang; Zhang, Dongxiao

    2014-05-01

    The ensemble Kalman filter (EnKF) is a widely used data assimilation method that has the capacity to sequentially update system parameters and states as new observations become available. One noticeable feature of the EnKF is that it not only can provide real-time updates of model parameters and state variables, but also can give the uncertainty associated with them in each assimilation step. The natural system is open and complex, rendering it prone to multiple interpretations and mathematical descriptions. In this paper, a multimodel data assimilation method is proposed by embedding the EnKF into the Bayesian model averaging framework to account for the uncertainty stemming from the model itself. An illustrative example, considering both hydrogeological and groundwater flow uncertainties, is employed to demonstrate the proposed multimodel data assimilation approach via the EnKF. Results show that statistical bias and uncertainty underestimation can occur when the data assimilation process relies on a single postulated model. The posterior model weight can adjust itself dynamically in time according to its consistency with observations. The performances of log conductivity estimation and head prediction are compared to the standard EnKF method based on the postulated single model and the proposed multimodel EnKF method. Comparisons show that the multimodel EnKF performs better in terms of statistical measures, such as log score and coverage, when sufficient observations have been assimilated in this case.

  20. Efficacy of lacosamide by focal seizure subtype.

    Science.gov (United States)

    Sperling, Michael R; Rosenow, Felix; Faught, Edward; Hebert, David; Doty, Pamela; Isojärvi, Jouko

    2014-10-01

    The purpose of this post hoc exploratory analysis was to determine the effects of the antiepileptic drug, lacosamide, on focal (partial-onset) seizure subtypes. Patient data from the three lacosamide pivotal trials were grouped and pooled by focal seizure subtype at Baseline: simple partial seizures (SPS), complex partial seizures (CPS), and secondarily generalized partial seizures (SGPS). Both efficacy outcomes (median percent change from Baseline to Maintenance Phase in seizure frequency per 28 days and the proportion of patients experiencing at least a 50% reduction in seizures) were evaluated by lacosamide dose (200, 400, or 600 mg/day) compared to placebo for each seizure subtype. An additional analysis was performed to determine whether a shift from more severe focal seizure subtypes to less severe occurred upon treatment with lacosamide. In patients with CPS or SGPS at Baseline, lacosamide 400 mg/day (maximum recommended daily dose) and 600 mg/day reduced the frequency of CPS and SGPS compared to placebo. Likewise, a proportion of patients with CPS and SGPS at Baseline experienced at least a 50% reduction in the frequency of CPS and SGPS (≥50% responder rate) in the lacosamide 400 and 600 mg/day groups compared with placebo. For both outcomes, numerically greatest responses were observed in the lacosamide 600 mg/day group among patients with SGPS at Baseline. In patients with SPS at Baseline, no difference between placebo and lacosamide was observed for either efficacy outcome. An additional exploratory analysis suggests that in patients with SPS at Baseline, CPS and SGPS may have been shifted to less severe SPS upon treatment with lacosamide. The results of these exploratory analyses revealed reductions in CPS and SGPS frequency with adjunctive lacosamide. Reduction in CPS and SGPS may confound assessment of SPS since the CPS or SGPS may possibly change to SPS by effective treatment. PMID:25082395

  1. Deterministic treatment of model error in geophysical data assimilation

    CERN Document Server

    Carrassi, Alberto

    2015-01-01

    This chapter describes a novel approach for the treatment of model error in geophysical data assimilation. In this method, model error is treated as a deterministic process fully correlated in time. This allows for the derivation of the evolution equations for the relevant moments of the model error statistics required in data assimilation procedures, along with an approximation suitable for application to large numerical models typical of environmental science. In this contribution we first derive the equations for the model error dynamics in the general case, and then for the particular situation of parametric error. We show how this deterministic description of the model error can be incorporated in sequential and variational data assimilation procedures. A numerical comparison with standard methods is given using low-order dynamical systems, prototypes of atmospheric circulation, and a realistic soil model. The deterministic approach proves to be very competitive with only minor additional computational c...

  2. Ambroxol-induced focal epileptic seizure.

    Science.gov (United States)

    Lapenta, Leonardo; Morano, Alessandra; Fattouch, Jinane; Casciato, Sara; Fanella, Martina; Giallonardo, Anna Teresa; Di Bonaventura, Carlo

    2014-01-01

    It is well known that in epileptic patients some compounds and different drugs used for the treatment of comorbidities can facilitate or provoke seizures, this evidence regarding a wide spectrum of pharmacological categories. The potential facilitating factors usually include direct toxic effects or pharmacological interactions of either active ingredients or excipients. We report the case of a patient with drug-resistant epilepsy who experienced focal epileptic seizures, easily and constantly reproducible, after each administration of a cough syrup. This is, to our knowledge, the first electroencephalogram-documented case of focal epileptic seizures induced by cough syrup containing ambroxol as active ingredient. PMID:24824664

  3. Biotelemetry system for Epilepsy Seizure Control

    Energy Technology Data Exchange (ETDEWEB)

    Smith, LaCurtise; Bohnert, George W.

    2009-07-02

    The Biotelemetry System for Epilepsy Seizure Control Project developed and tested an automated telemetry system for use in an epileptic seizure prevention device that precisely controls localized brain temperature. This project was a result of a Department of Energy (DOE) Global Initiatives for Proliferation Prevention (GIPP) grant to the Kansas City Plant (KCP), Argonne National Laboratory (ANL), and Pacific Northwest National Laboratory (PNNL) to partner with Flint Hills Scientific, LLC, Lawrence, KS and Biophysical Laboratory Ltd (BIOFIL), Sarov, Russia to develop a method to help control epileptic seizures.

  4. WAVE ASSIMILATION AND NUMERICAL PREDICTION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An adjoint variational method for wave data assimilation in the LAGFD-WAM wave model is proposed. The adjoint equation of the wavenumber energy spectrum balance equation is derived. And fortunately, its characteristic equations are the same as those in the LAGFD-WAM wave model. Simple experiments on the functional optimization and assimilation effectiveness during the prediction period indicated that the adjoint variational method is effective for wave assimilation and that the initial optimization of the wave model is important for the short-range wave prediction. All of this is under the assumption that the wind field is accurate, the method is the important first step for combined wind and wave data assimilation systems.

  5. Global Data Assimilation System (GDAS)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Data Assimilation System (GDAS) is the system used by the Global Forecast System (GFS) model to place observations into a gridded model space for the...

  6. Global Land Data Assimilation System

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The goal of the Global Land Data Assimilation System (GLDAS) is to ingest satellite- and ground-based observational data products, using advanced land surface...

  7. Development of an EUV data assimilation technique for plasmasphere modeling

    International Nuclear Information System (INIS)

    Complete text of publication follows. The structure of the plasmasphere is strongly controlled by the electric field imposed on the magnetosphere. In order to model the dynamics of the plasmasphere, it is important to know the spatial structure of the electric potential in the inner magnetosphere. However, since it is difficult to know the global electric potential distribution in the magnetosphere due to the lack of observation, it is difficult to grasp the dynamics of the plasmasphere using in-situ measurements. Recently we have developed a data assimilation technique which incorporates a remote observation of energetic neutral atoms (ENAs) from the IMAGE satellite into a ring current model. This ENA data assimilation technique provides estimates of the distributions of the ring current ions and electric potential in the inner magnetosphere. The present study is conducted aiming at applying a similar approach for modeling the plasmasphere. We are now engaged in the development of a data assimilation technique for providing estimates of the spatial structures of the plasmasphere and electric potential. The estimation is performed by incorporating remote imaging data of extreme ultra-violet (EUV) from the IMAGE satellite into a simulation model of the plasmasphere. We assume the magnetospheric electric potential distribution to be unknown, and estimate it in the course of the assimilation process. The plasmaspheric ion distribution is estimated according to the estimated electric potential and the plasmasphere simulation model. At present, we are conducting data assimilation experiments using artificial EUV data sets to evaluate the EUV data assimilation approach. The experimental result suggests that the data assimilation of the EUV imaging data provides useful information for understanding the temporal and spatial variations of the plasmasphere.

  8. Diurnal dynamics of photosynthetic parameters of Norway spruce trees cultivated under ambient and elevated CO2: the reasons of midday depression in CO2 assimilation

    Czech Academy of Sciences Publication Activity Database

    Špunda, V.; Kalina, J.; Urban, Otmar; Luis, V.C.; Sibisse, I.; Puértolas, J.; Šprtová, Miroslava; Marek, Michal V.

    2005-01-01

    Roč. 168, č. 5 (2005), s. 1371-1381. ISSN 0168-9452 R&D Projects: GA MŠk(CZ) LN00A141; GA MŠk(CZ) 1P04OCE21.001; GA AV ČR(CZ) IBS6087005; GA MŽP SM/640/18/03 Grant ostatní: EU(CZ) HPRI-CT-2002-00197 Institutional research plan: CEZ:AV0Z60870520 Keywords : daily course of photosynthesis * elevated CO2 * dynamics of acclimation depression of photosynthesis Subject RIV: ED - Physiology Impact factor: 1.605, year: 2005

  9. Data Assimilation Applications in Hydrology

    OpenAIRE

    Deliu, Ciprian; Giurma, Ion

    2014-01-01

    In this paper we review some data assimilation applications in hydrology and we investigate the benefits of applying the ensemble Kalman filter methods on a specific hydrodynamic model of a river network using the MIKE 11 software. We explore the efects of assimilating measurements from different locations (generated by a reference model) into a model forced with erroneous boundary conditions and also examine the effect of using coloured noise for describing uncertainty in the upstream bounda...

  10. Ethnic goods and immigrant assimilation

    OpenAIRE

    Abdulloev, Ilhom; Epstein, Gil S.; Ira N. Gang

    2014-01-01

    Some immigrants try to keep their ethnicity hidden while others become ever deeply more mired in their home culture. We argue that among immigrants this struggle manifests itself in the ethnic goods they choose to consume. Different types of ethnic goods have vastly different effects on immigrant assimilation. We develop a simple theoretical model useful for capturing the consequences of this struggle, illustrating it with examples of Central Asian assimilation into the Muscovite economy.

  11. Pathophysiology of Tonic Muscle Activation During Epileptic Seizures

    DEFF Research Database (Denmark)

    Beniczky, S.; Conradsen, Isa; Wolf, P.; Sams, Thomas; Sørensen, Helge Bjarup Dissing

    Tonic seizures and the tonic phase of tonic-clonic epileptic seizures are defined as a “sustained tonic” muscle contraction. Visual inspection of the surface electromyograms (sEMG) during seizures significantly contributed to a better understanding and diagnosis of several seizure types. However,...

  12. Neonatal seizures triple the risk of a remote seizure after perinatal ischemic stroke.

    OpenAIRE

    Fox, CK; Glass, HC; Sidney, S; Smith, SE; Fullerton, HJ

    2016-01-01

    To determine incidence rates and risk factors of remote seizure after perinatal arterial ischemic stroke.We retrospectively identified a population-based cohort of children with perinatal arterial ischemic stroke (presenting acutely or in a delayed fashion) from a large Northern Californian integrated health care system. We determined incidence and predictors of a remote seizure (unprovoked seizure after neonatal period, defined as 28 days of life) by survival analyses, and measured epilepsy ...

  13. Seizures in Adults (Beyond the Basics)

    Science.gov (United States)

    ... triggers, such as strong emotions, intense exercise, loud music, or flashing lights. When these triggers are at ... may not believe it because you have no memory of the event. The period following a seizure ...

  14. Seizures associated with Lupus during pregnancy

    OpenAIRE

    Aoki, Shigeru; KOBAYASHI, Natsuko; Mochimaru, Aya; Takahashi, Tsuneo; Hirahara, Fumiki

    2016-01-01

    Key Clinical Message A sudden flare of previously stable SLE may give rise to CNS lupus. During pregnancy, seizures associated with CNS lupus can cause hypoxic‐ischemic encephalopathy (HIE) in the infant.

  15. Serum Prolactin in Diagnosis of Epileptic Seizures

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2005-09-01

    Full Text Available The results of studies in databases and references concerning serum prolactin levels (PRL in patients with suspected seizures were rated for quality and analyzed by members of the Therapeutics Subcommittee of the American Academy of Neurology.

  16. Seizures and Munchausen Syndrome by Proxy

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2002-05-01

    Full Text Available The prevalence, morbidity and mortality, diagnosis and management of cases of fabricated seizures and child abuse (Munchausen syndrome by proxy (MSbp are assessed by pediatricians at the University of Wales College of Medicine, Cardiff, UK.

  17. Febrile Seizures and Epilepsy: Possible Outcomes

    Science.gov (United States)

    ... status epilepticus in children: The FEB- STAT Study. Neurology 2012;79:871– 877. 2. Graves RC, Oehler ... Am J Epidemiol 2007;165:911–918. e82 Neurology 79 August 28, 2012 Febrile seizures: Possible outcomes ...

  18. Improving carbon model phenology using data assimilation

    Science.gov (United States)

    Exrayat, Jean-François; Smallman, T. Luke; Bloom, A. Anthony; Williams, Mathew

    2015-04-01

    Carbon cycle dynamics is significantly impacted by ecosystem phenology, leading to substantial seasonal and inter-annual variation in the global carbon balance. Representing inter-annual variability is key for predicting the response of the terrestrial ecosystem to climate change and disturbance. Existing terrestrial ecosystem models (TEMs) often struggle to accurately simulate observed inter-annual variability. TEMs often use different phenological models based on plant functional type (PFT) assumptions. Moreover, due to a high level of computational overhead in TEMs they are unable to take advantage of globally available datasets to calibrate their models. Here we describe the novel CARbon DAta MOdel fraMework (CARDAMOM) for data assimilation. CARDAMOM is used to calibrate the Data Assimilation Linked Ecosystem Carbon version 2 (DALEC2) model using Bayes' Theorem within a Metropolis Hastings - Markov Chain Monte Carlo (MH-MCMC). CARDAMOM provides a framework which combines knowledge from observations, such as remotely sensed LAI, and heuristic information in the form of Ecological and Dynamical Constraints (EDCs). The EDCs are representative of real world processes and constrain parameter interdependencies and constrain carbon dynamics. We used CARDAMOM to bring together globally spanning datasets of LAI and the DALEC2 and DALEC2-GSI models. These analyses allow us to investigate the sensitivity ecosystem processes to the representation of phenology. DALEC2 uses an analytically solved model of phenology which is invariant between years. In contrast DALEC2-GSI uses a growing season index (GSI) calculated as a function of temperature, vapour pressure deficit (VPD) and photoperiod to calculate bud-burst and leaf senescence, allowing the model to simulate inter-annual variability in response to climate. Neither model makes any PFT assumptions about the phenological controls of a given ecosystem, allowing the data alone to determine the impact of the meteorological

  19. Aging Models of Acute Seizures and Epilepsy

    OpenAIRE

    Kelly, Kevin M.

    2010-01-01

    Aged animals have been used by researchers to better understand the differences between the young and the aged brain and how these differences may provide insight into the mechanisms of acute seizures and epilepsy in the elderly. To date, there have been relatively few studies dedicated to the modeling of acute seizures and epilepsy in aged, healthy animals. Inherent challenges to this area of research include the costs associated with the purchase and maintenance of older animals and, at tim...

  20. Seizures and Praziquantel. A case report

    OpenAIRE

    Jaime R. Torres R.; Oscar Noya G.; Belkysyolé A. de Noya; Alejandro Mondolfi G.

    1988-01-01

    A 27 year Old male developed seizures after receiving a single 20 mg/kg dose of praziquantel for the treatment of an intestinal Hymenolepis nana infection. On further clinical and laboratorial evaluations, he was found to suffer from an until then asymptomatic parenchymal brain cysticercosis. Praziquantel must be used with caution in those areas where cysticercosis represents a mayor public health problem. The occurrence of unexpected seizures in an individual being treated with the compound,...

  1. Cerebrospinal fluid findings after epileptic seizures.

    Science.gov (United States)

    Chatzikonstantinou, Anastasios; Ebert, Anne D; Hennerici, Michael G

    2015-12-01

    We aimed to evaluate ictally-induced CSF parameter changes after seizures in adult patients without acute inflammatory diseases or infectious diseases associated with the central nervous system. In total, 151 patients were included in the study. All patients were admitted to our department of neurology following acute seizures and received an extensive work-up including EEG, cerebral imaging, and CSF examinations. CSF protein elevation was found in most patients (92; 60.9%) and was significantly associated with older age, male sex, and generalized seizures. Abnormal CSF-to-serum glucose ratio was found in only nine patients (5.9%) and did not show any significant associations. CSF lactate was elevated in 34 patients (22.5%) and showed a significant association with focal seizures with impaired consciousness, status epilepticus, the presence of EEG abnormalities in general and epileptiform potentials in particular, as well as epileptogenic lesions on cerebral imaging. Our results indicate that non-inflammatory CSF elevation of protein and lactate after epileptic seizures is relatively common, in contrast to changes in CSF-to-serum glucose ratio, and further suggest that these changes are caused by ictal activity and are related to seizure type and intensity. We found no indication that these changes may have further-reaching pathological implications besides their postictal character. PMID:26575850

  2. Millimeter-scale epileptiform spike propagation patterns and their relationship to seizures

    Science.gov (United States)

    Vanleer, Ann C.; Blanco, Justin A.; Wagenaar, Joost B.; Viventi, Jonathan; Contreras, Diego; Litt, Brian

    2016-04-01

    Objective. Current mapping of epileptic networks in patients prior to epilepsy surgery utilizes electrode arrays with sparse spatial sampling (∼1.0 cm inter-electrode spacing). Recent research demonstrates that sub-millimeter, cortical-column-scale domains have a role in seizure generation that may be clinically significant. We use high-resolution, active, flexible surface electrode arrays with 500 μm inter-electrode spacing to explore epileptiform local field potential (LFP) spike propagation patterns in two dimensions recorded from subdural micro-electrocorticographic signals in vivo in cat. In this study, we aimed to develop methods to quantitatively characterize the spatiotemporal dynamics of epileptiform activity at high-resolution. Approach. We topically administered a GABA-antagonist, picrotoxin, to induce acute neocortical epileptiform activity leading up to discrete electrographic seizures. We extracted features from LFP spikes to characterize spatiotemporal patterns in these events. We then tested the hypothesis that two-dimensional spike patterns during seizures were different from those between seizures. Main results. We showed that spatially correlated events can be used to distinguish ictal versus interictal spikes. Significance. We conclude that sub-millimeter-scale spatiotemporal spike patterns reveal network dynamics that are invisible to standard clinical recordings and contain information related to seizure-state.

  3. Comparison of different assimilation schemes in a sequential Kalman filter assimilation system

    OpenAIRE

    Yan, Yajing; Barth, Alexander; Beckers, Jean-Marie

    2014-01-01

    In this paper, four assimilation schemes, including an intermittent assimilation scheme (INT) and three incremental assimilation schemes (IAU 0, IAU 50 and IAU 100), are compared in the same assimilation experiments with a nonlinear ocean circulation model using the Ensemble Kalman Filter as assimilation method. The three IAU schemes differ from each other in the position of the increment update window that has the same size as the assimilation window. 0, 50 and 100 correspond to the degree o...

  4. Mozart K.448 listening decreased seizure recurrence and epileptiform discharges in children with first unprovoked seizures: a randomized controlled study

    OpenAIRE

    Lin, Lung-Chang; Lee, Mei-Wen; Wei, Ruey-Chang; Mok, Hin-Kiu; Yang, Rei-Cheng

    2014-01-01

    Background Increasing numbers of reports show the beneficial effects of listening to Mozart music in decreasing epileptiform discharges as well as seizure frequency in epileptic children. There has been no effective method to reduce seizure recurrence after the first unprovoked seizure until now. In this study, we investigated the effect of listening to Mozart K.448 in reducing the seizure recurrence rate in children with first unprovoked seizures. Methods Forty-eight children who experienced...

  5. Physically-based data assimilation

    Directory of Open Access Journals (Sweden)

    G. Levy

    2010-05-01

    Full Text Available Ideally, a validation and assimilation scheme should maintain the physical principles embodied in the model and be able to evaluate and assimilate lower dimensional features (e.g., discontinuities contained within a bulk simulation, even when these features are not directly observed or represented by model variables. We present such a scheme and suggest its potential to resolve or alleviate some outstanding problems that stem from making and applying required, yet often non-physical, assumptions and procedures in common operational data assimilation. As proof of concept, we use a sea-ice model with remotely sensed observations of leads in a one-step assimilation cycle. Using the new scheme in a sixteen day simulation experiment introduces model skill (against persistence several days earlier than in the control run, improves the overall model skill and delays its drop off at later stages of the simulation. The potential and requirements to extend this scheme to different applications, and to both empirical and statistical multivariate and full cycle data assimilation schemes, are discussed.

  6. Physically-based data assimilation

    Directory of Open Access Journals (Sweden)

    G. Levy

    2010-11-01

    Full Text Available Ideally, a validation and assimilation scheme should maintain the physical principles embodied in the model and be able to evaluate and assimilate lower dimensional features (e.g., discontinuities contained within a bulk simulation, even when these features are not directly observed or represented by model variables. We present such a scheme and suggest its potential to resolve or alleviate some outstanding problems that stem from making and applying required, yet often non-physical, assumptions and procedures in common operational data assimilation. As proof of concept, we use a sea-ice model with remotely sensed observations of leads in a one-step assimilation cycle. Using the new scheme in a sixteen day simulation experiment introduces model skill (against persistence several days earlier than in the control run, improves the overall model skill and delays its drop off at later stages of the simulation. The potential and requirements to extend this scheme to different applications, and to both empirical and statistical multivariate and full cycle data assimilation schemes, are discussed.

  7. Physically-based data assimilation

    Science.gov (United States)

    Levy, G.; Coon, M.; Nguyen, G.; Sulsky, D.

    2010-11-01

    Ideally, a validation and assimilation scheme should maintain the physical principles embodied in the model and be able to evaluate and assimilate lower dimensional features (e.g., discontinuities) contained within a bulk simulation, even when these features are not directly observed or represented by model variables. We present such a scheme and suggest its potential to resolve or alleviate some outstanding problems that stem from making and applying required, yet often non-physical, assumptions and procedures in common operational data assimilation. As proof of concept, we use a sea-ice model with remotely sensed observations of leads in a one-step assimilation cycle. Using the new scheme in a sixteen day simulation experiment introduces model skill (against persistence) several days earlier than in the control run, improves the overall model skill and delays its drop off at later stages of the simulation. The potential and requirements to extend this scheme to different applications, and to both empirical and statistical multivariate and full cycle data assimilation schemes, are discussed.

  8. Improving the Horizontal Transport in the Lower Troposphere with Four Dimensional Data Assimilation

    Science.gov (United States)

    The physical processes involved in air quality modeling are governed by dynamically-generated meteorological model fields. This research focuses on reducing the uncertainty in the horizontal transport in the lower troposphere by improving the four dimensional data assimilation (F...

  9. Seizures and Teens: When Seizures Aren't the Only Problem

    Science.gov (United States)

    Kanner, Andres M.; Shafer, Patricia O.

    2006-01-01

    Some teenagers with epilepsy only have to deal with seizures, which can be tough enough, but for other teens, seizures are not the only problem. Parents and caregivers often report changes in their teens' abilities to think clearly, learn in school, or remain focused in class. Mood and other behavioral problems may also be seen. It is critical…

  10. Impact of Assimilated and Interactive Aerosol on Tropical Cyclogenesis

    Science.gov (United States)

    Reale, O.; Lau, K. M.; daSilva, A.; Matsui, T.

    2014-01-01

    This article investigates the impact 3 of Saharan dust on the development of tropical cyclones in the Atlantic. A global data assimilation and forecast system, the NASA GEOS-5, is used to assimilate all satellite and conventional data sets used operationally for numerical weather prediction. In addition, this new GEOS-5 version includes assimilation of aerosol optical depth from the Moderate Resolution Imaging Spectroradiometer (MODIS). The analysis so obtained comprises atmospheric quantities and a realistic 3-d aerosol and cloud distribution, consistent with the meteorology and validated against Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and CloudSat data. These improved analyses are used to initialize GEOS-5 forecasts, explicitly accounting for aerosol direct radiative effects and their impact on the atmospheric dynamics. Parallel simulations with/without aerosol radiative effects show that effects of dust on static stability increase with time, becoming highly significant after day 5 and producing an environment less favorable to tropical cyclogenesis.

  11. Data Assimilation Cycling for Weather Analysis

    Science.gov (United States)

    Tran, Nam; Li, Yongzuo; Fitzpatrick, Patrick

    2008-01-01

    This software package runs the atmospheric model MM5 in data assimilation cycling mode to produce an optimized weather analysis, including the ability to insert or adjust a hurricane vortex. The program runs MM5 through a cycle of short forecasts every three hours where the vortex is adjusted to match the observed hurricane location and storm intensity. This technique adjusts the surrounding environment so that the proper steering current and environmental shear are achieved. MM5cycle uses a Cressman analysis to blend observation into model fields to get a more accurate weather analysis. Quality control of observations is also done in every cycle to remove bad data that may contaminate the analysis. This technique can assimilate and propagate data in time from intermittent and infrequent observations while maintaining the atmospheric field in a dynamically balanced state. The software consists of a C-shell script (MM5cycle.driver) and three FORTRAN programs (splitMM5files.F, comRegrid.F, and insert_vortex.F), and are contained in the pre-processor component of MM5 called "Regridder." The model is first initialized with data from a global model such as the Global Forecast System (GFS), which also provides lateral boundary conditions. These data are separated into single-time files using splitMM5.F. The hurricane vortex is then bogussed in the correct location and with the correct wind field using insert_vortex.F. The modified initial and boundary conditions are then recombined into the model fields using comRegrid.F. The model then makes a three-hour forecast. The three-hour forecast data from MM5 now become the analysis for the next short forecast run, where the vortex will again be adjusted. The process repeats itself until the desired time of analysis is achieved. This code can also assimilate observations if desired.

  12. Storm surge variational assimilation model

    Directory of Open Access Journals (Sweden)

    Shi-li HUANG

    2010-06-01

    Full Text Available To eliminate errors caused by uncertainty of parameters and further improve capability of storm surge forecasting, the variational data assimilation method is applied to the storm surge model based on unstructured grid with high spatial resolution. The method can effectively improve the forecasting accuracy of storm surge induced by typhoon through controlling wind drag force coefficient parameter. The model is first theoretically validated with synthetic data. Then, the real storm surge process induced by the TC 0515 typhoon is forecasted by the variational data assimilation model, and results show the feasibility of practical application.

  13. Febrile Seizures: Etiology, Prevalence, and Geographical Variation

    Directory of Open Access Journals (Sweden)

    Ali DELPISHEH

    2014-07-01

    Full Text Available How to Cite This Article: Delpisheh A, Veisani Y, Sayehmiri K, Fayyazi A. Febrile Seizures: Etiology, Prevalence, and Geographical Variation. Iran J Child Neurol. 2014 Summer; 8(3:30-37. AbstractObjectiveFebrile seizures (FSs are the most common neurological disorder observed in the pediatric age group. The present study provides information about epidemiological and clinical characteristics as well as risk factors associated with FS among Iranian children.Materials & MethodsOn the computerized literature valid databases, the FS prevalence and 95% confidence intervals were calculated using a random effects model. A metaregression analysis was introduced to explore heterogeneity between studies. Data manipulation and statistical analyses were performed using Stata10.ResultsThe important viral or bacterial infection causes of FSs were; recent upper respiratory infection 42.3% (95% CI: 37.2%–47.4%, gastroenteritis21.5% (95% CI: 13.6%–29.4%, and otitis media infections15.2% (95% CI: 9.8%- 20.7% respectively. The pooled prevalence rate of FS among other childhood convulsions was 47.9% (95% CI: 38.8–59.9%. The meta–regression analysis showed that the sample size does not significantly affect heterogeneity for the factor ‘prevalence FS’.ConclusionsAlmost half of all childhood convulsions among Iranian children are associated with Febrile seizure. ReferencesFelipe L, Siqueira M. febrile seizures: update on diagnosis and management. Siqueira LFM. 2010;56 (4:489–92.Oka E, Ishida S, Ohtsuka Y, Ohtahara S. Neuroepidemiological Study of Childhood Epilepsy by Application of International Classification of Epilepsies and Epileptic Syndromes (ILAE, 1989. Epilepsia. 1995;36 (7:658–61.Shi X, Lin Z, Ye X, Hu Y, Zheng F, Hu H. An epidemiological survey of febrile convulsions among pupils in the Wenzhou region. Zhongguo Dang Dai Er Ke Za Zhi. 2012 Feb;14 (2:128–30.Waruiru C, Appleton R. Febrile seizures: an update. Arch Dis Child

  14. Quantitative analysis of surface electromyography during epileptic and nonepileptic convulsive seizures

    DEFF Research Database (Denmark)

    Beniczky, Sándor; Conradsen, Isa; Moldovan, Mihai;

    2014-01-01

    tonic-clonic seizures (GTCS) from 14 patients with epilepsy, and 18 convulsive PNES from 12 patients (one patient had both GTCS and PNES). The healthy controls were simulating GTCS. To quantitatively characterize the signals we calculated the following parameters: root mean square (RMS) of the amplitude...... seizure, and separation between the tonic and the clonic phases distinguished at group-level but not at individual level between convulsive PNES and GTCS. RMS, temporal dynamics of the HF/LF ratio, and the evolution of the silent periods differentiated between epileptic and nonepileptic convulsive...

  15. Data assimilation the ensemble Kalman filter

    CERN Document Server

    Evensen, Geir

    2006-01-01

    Covers data assimilation and inverse methods, including both traditional state estimation and parameter estimation. This text and reference focuses on various popular data assimilation methods, such as weak and strong constraint variational methods and ensemble filters and smoothers.

  16. Non-invasive imaging of epileptic seizures in vivo using photoacoustic tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Qizhi; Carney, Paul R; Yuan Zhen; Jiang Huabei [J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611 (United States); Liu Zhao [Department of Pediatrics, Division of Pediatric Neurology, University of Florida, Gainesville, FL 32610 (United States); Chen Huanxin; Roper, Steven N [Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0265 (United States)], E-mail: hjiang@bme.ufl.edu

    2008-04-07

    Non-invasive laser-induced photoacoustic tomography (PAT) is an emerging imaging modality that has the potential to image the dynamic function of the brain due to its unique ability of imaging biological tissues with high optical contrast and ultrasound resolution. Here we report the first application of our finite-element-based PAT for imaging of epileptic seizures in an animal model. In vivo photoacoustic images were obtained in rats with focal seizures induced by microinjection of bicuculline, a GABA{sub A} antagonist, into the neocortex. The seizure focus was accurately localized by PAT as confirmed with gold-standard electroencephalogram (EEG). Compared to the existing neuroimaging modalities, PAT not only has the unprecedented advantage of high spatial and temporal resolution in a single imaging modality, but also is portable and low in cost, making it possible to bring brain imaging to the bedside.

  17. Epileptic Seizure Prediction by a System of Particle Filter Associated with a Neural Network

    Directory of Open Access Journals (Sweden)

    Derong Liu

    2009-01-01

    Full Text Available None of the current epileptic seizure prediction methods can widely be accepted, due to their poor consistency in performance. In this work, we have developed a novel approach to analyze intracranial EEG data. The energy of the frequency band of 4–12 Hz is obtained by wavelet transform. A dynamic model is introduced to describe the process and a hidden variable is included. The hidden variable can be considered as indicator of seizure activities. The method of particle filter associated with a neural network is used to calculate the hidden variable. Six patients' intracranial EEG data are used to test our algorithm including 39 hours of ictal EEG with 22 seizures and 70 hours of normal EEG recordings. The minimum least square error algorithm is applied to determine optimal parameters in the model adaptively. The results show that our algorithm can successfully predict 15 out of 16 seizures and the average prediction time is 38.5 minutes before seizure onset. The sensitivity is about 93.75% and the specificity (false prediction rate is approximately 0.09 FP/h. A random predictor is used to calculate the sensitivity under significance level of 5%. Compared to the random predictor, our method achieved much better performance.

  18. Febrile Seizure: Demographic Features and Causative Factors

    Directory of Open Access Journals (Sweden)

    Hamed ESMAILI GOURABI

    2013-01-01

    Full Text Available How to cite this article: Esmaili Gourabi H, Bidabadi E, Cheraghalipour  F, Aarabi  Y, Salamat F. Febrile Seizure: Demographic Features and Causative Factors. Iran J Child Neurol Autumn 2012; 6(4:33-37.Abstract Objective Because of geographical and periodical variation, we prompted to determine the demographic features and causative factors for febrile seizure in Rasht. Materials & Methods In this cross-sectional study, all 6–month- to 6-year-old children with the diagnosis of febrile seizure admitted to 17 Shahrivar hospital in Rasht, from August, 2009 to August, 2010 were studied. Age, sex, family history of the disease, seizure types, body temperature upon admission and infectious causes of the fever were recorded. All statistical analysis was performed with SPSS software, version 16. Results Of the 214 children (mean age, 25.24±15.40 months, 124 were boys and 109 had a positive family history. Complex seizures were seen in 39 cases. In patients with a complex febrile seizure, 59% had the repetitive type, 20.5% had the focal type and 20.5% had more than 15 minutes duration of seizures. Most of the repetitive seizures (78.3% occurred in patients under 2 years old; the difference between under and over 2-year-old patients was statistically significant (P=0.02. Study results did not show significant differences between the two genders for simple or complex seizures. The mean body temperature upon admission was 38.2±1.32◦C (38.31±0.82 degrees in boys and 38.04±1.78 in girls. Upper respiratory infections were seen in most patients (74.29%. All cases of lower respiratory infections were boys. There was a statistically significant difference between boys and girls in causes of fever. Conclusion Most of the children had a positive family history and the most common causative factor was upper respiratory infection.  References: Huang MC, Huang CC, Thomas K. Febrile convulsions: development and validation of a questionnaire to measure

  19. Data Assimilation by delay-coordinate nudging

    Science.gov (United States)

    Pazo, Diego; Lopez, Juan Manuel; Carrassi, Alberto

    2016-04-01

    A new nudging method for data assimilation, delay-coordinate nudging, is presented. Delay-coordinate nudging makes explicit use of present and past observations in the formulation of the forcing driving the model evolution at each time-step. Numerical experiments with a low order chaotic system show that the new method systematically outperforms standard nudging in different model and observational scenarios, also when using an un-optimized formulation of the delay-nudging coefficients. A connection between the optimal delay and the dominant Lyapunov exponent of the dynamics is found based on heuristic arguments and is confirmed by the numerical results, providing a guideline for the practical implementation of the algorithm. Delay-coordinate nudging preserves the easiness of implementation, the intuitive functioning and the reduced computational cost of the standard nudging, making it a potential alternative especially in the field of seasonal-to-decadal predictions with large Earth system models that limit the use of more sophisticated data assimilation procedures.

  20. Continuous data assimilation with stochastically noisy data

    International Nuclear Information System (INIS)

    We analyse the performance of a data-assimilation algorithm based on a linear feedback control when used with observational data that contains measurement errors. Our model problem consists of dynamics governed by the two-dimensional incompressible Navier–Stokes equations, observational measurements given by finite volume elements or nodal points of the velocity field and measurement errors which are represented by stochastic noise. Under these assumptions, the data-assimilation algorithm consists of a system of stochastically forced Navier–Stokes equations. The main result of this paper provides explicit conditions on the observation density (resolution) which guarantee explicit asymptotic bounds, as the time tends to infinity, on the error between the approximate solution and the actual solutions which is corresponding to these measurements, in terms of the variance of the noise in the measurements. Specifically, such bounds are given for the limit supremum, as the time tends to infinity, of the expected value of the L2-norm and of the H1 Sobolev norm of the difference between the approximating solution and the actual solution. Moreover, results on the average time error in mean are stated. (paper)

  1. Data assimilation applied to a chaotic toy climate

    CERN Document Server

    Harris, Kameron Decker; Hitt, Darren L; Danforth, Christopher M

    2011-01-01

    A simplified model of natural convection, similar to the 1963 Lorenz system, is derived and compared to computational fluid dynamics simulations as a test bed for data assimilation methods. The thermosyphon is represented by a long time flow simulation, which serves as a reference "truth". Forecasts are then made using the Lorenz-like model and synchronized to noisy and limited observations of the truth, a realistic \\textit{in silico} forecasting scenario, using three dimensional variational filtering, the extended Kalman filter, the ensemble square root filter, and the ensemble transform Kalman filter. We find that these data assimilation algorithms successfully couple the simplified model to observations of the computational fluid dynamics simulation and, in fact, can infer dynamics absent from the model.

  2. Febrile Seizures and Febrile Seizure Syndromes: An Updated Overview of Old and Current Knowledge

    Directory of Open Access Journals (Sweden)

    Abdulhafeez M. Khair

    2015-01-01

    Full Text Available Febrile seizures are the most common paroxysmal episode during childhood, affecting up to one in 10 children. They are a major cause of emergency facility visits and a source of family distress and anxiety. Their etiology and pathophysiological pathways are being understood better over time; however, there is still more to learn. Genetic predisposition is thought to be a major contributor. Febrile seizures have been historically classified as benign; however, many emerging febrile seizure syndromes behave differently. The way in which human knowledge has evolved over the years in regard to febrile seizures has not been dealt with in depth in the current literature, up to our current knowledge. This review serves as a documentary of how scientists have explored febrile seizures, elaborating on the journey of knowledge as far as etiology, clinical features, approach, and treatment strategies are concerned. Although this review cannot cover all clinical aspects related to febrile seizures at the textbook level, we believe it can function as a quick summary of the past and current sources of knowledge for all varieties of febrile seizure types and syndromes.

  3. Reducing premature KCC2 expression rescues seizure susceptibility and spine morphology in atypical febrile seizures.

    Science.gov (United States)

    Awad, Patricia N; Sanon, Nathalie T; Chattopadhyaya, Bidisha; Carriço, Josianne Nunes; Ouardouz, Mohamed; Gagné, Jonathan; Duss, Sandra; Wolf, Daniele; Desgent, Sébastien; Cancedda, Laura; Carmant, Lionel; Di Cristo, Graziella

    2016-07-01

    Atypical febrile seizures are considered a risk factor for epilepsy onset and cognitive impairments later in life. Patients with temporal lobe epilepsy and a history of atypical febrile seizures often carry a cortical malformation. This association has led to the hypothesis that the presence of a cortical dysplasia exacerbates febrile seizures in infancy, in turn increasing the risk for neurological sequelae. The mechanisms linking these events are currently poorly understood. Potassium-chloride cotransporter KCC2 affects several aspects of neuronal circuit development and function, by modulating GABAergic transmission and excitatory synapse formation. Recent data suggest that KCC2 downregulation contributes to seizure generation in the epileptic adult brain, but its role in the developing brain is still controversial. In a rodent model of atypical febrile seizures, combining a cortical dysplasia and hyperthermia-induced seizures (LHS rats), we found a premature and sustained increase in KCC2 protein levels, accompanied by a negative shift of the reversal potential of GABA. In parallel, we observed a significant reduction in dendritic spine size and mEPSC amplitude in CA1 pyramidal neurons, accompanied by spatial memory deficits. To investigate whether KCC2 premature overexpression plays a role in seizure susceptibility and synaptic alterations, we reduced KCC2 expression selectively in hippocampal pyramidal neurons by in utero electroporation of shRNA. Remarkably, KCC2 shRNA-electroporated LHS rats show reduced hyperthermia-induced seizure susceptibility, while dendritic spine size deficits were rescued. Our findings demonstrate that KCC2 overexpression in a compromised developing brain increases febrile seizure susceptibility and contribute to dendritic spine alterations. PMID:26875662

  4. A framework for variational data assimilation with superparameterization

    Science.gov (United States)

    Grooms, I.; Lee, Y.

    2015-10-01

    Superparameterization (SP) is a multiscale computational approach wherein a large scale atmosphere or ocean model is coupled to an array of simulations of small scale dynamics on periodic domains embedded into the computational grid of the large scale model. SP has been successfully developed in global atmosphere and climate models, and is a promising approach for new applications, but there is currently no practical data assimilation framework that can be used with these models. The authors develop a 3D-Var variational data assimilation framework for use with SP; the relatively low cost and simplicity of 3D-Var in comparison with ensemble approaches makes it a natural fit for relatively expensive multiscale SP models. To demonstrate the assimilation framework in a simple model, the authors develop a new system of ordinary differential equations similar to the two-scale Lorenz-'96 model. The system has one set of variables denoted {Yi}, with large and small scale parts, and the SP approximation to the system is straightforward. With the new assimilation framework the SP model approximates the large scale dynamics of the true system accurately.

  5. S100B proteins in febrile seizures

    DEFF Research Database (Denmark)

    Mikkonen, Kirsi; Pekkala, Niina; Pokka, Tytti; Romner, Bertil; Uhari, Matti; Rantala, Heikki

    2011-01-01

    may also give an indication of an ongoing pathological process in the brain with respect to febrile seizures (FS) and the likelihood of their recurrence. To evaluate this, we measured S100B protein concentrations in serum and cerebrospinal fluid from 103 children after their first FS. 33 children with...... the hospital after FS and S100B concentration in serum (r=-0.130, P=0.28) or in cerebrospinal fluid samples (r=-0.091, P=0.52). Our findings indicate that FS does not cause significant blood-brain barrier openings, and increase the evidence that these seizures are relatively harmless for the...

  6. Febrile Seizures: Etiology, Prevalence, and Geographical Variation

    OpenAIRE

    Delpisheh, Ali; Veisani, Yousef; SAYEHMIRI, Kourosh; FAYYAZI, Afshin

    2014-01-01

    How to Cite This Article: Delpisheh A, Veisani Y, Sayehmiri K, Fayyazi A. Febrile Seizures: Etiology, Prevalence, and Geographical Variation. Iran J Child Neurol. 2014 Summer; 8(3):30-37. AbstractObjectiveFebrile seizures (FSs) are the most common neurological disorder observed in the pediatric age group. The present study provides information about epidemiological and clinical characteristics as well as risk factors associated with FS among Iranian children.Materials & MethodsOn the comp...

  7. Seizures due to high dose camphor ingestion.

    Science.gov (United States)

    Tekin, Hande Gazeteci; Gökben, Sarenur; Serdaroğlu, Gül

    2015-12-01

    Camphor is a cyclic ketone of the hydro aromatic terpene group. Today it is frequently used as a prescription or non-prescription topical antitussive, analgesic, anesthetic and antipruritic agent. Camphor which is considered an innocent drug by parents and physicians is a common household item which can lead to severe poisoning in children even when taken in small amounts. Neurotoxicity in the form of seizures can ocur soon after ingestion. A two-year old female patient who presented with a complaint of generalized tonic-clonic seizures after oral ingestion of camphor is presented. PMID:26884696

  8. 19 CFR 162.92 - Notice of seizure.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Civil Asset Forfeiture Reform Act § 162.92 Notice of seizure. (a... or physical safety of an individual; (ii) Flight from prosecution; (iii) Destruction of or...

  9. FACTORS TRIGGERING EPILEPTIC SEIZURES IN PATIENTS OVER 50 YEARS

    OpenAIRE

    Demir, Serkan; Rifat Erdem TOGROL; Sonkaya, Ali Riza; Kendirli, Mustafa Tansel; Alay, Semih; Celik, Tugba Yanar; Delil, Sakir; Ozdag, Mehmet Fatih

    2016-01-01

    Objective:In this study the factors that trigger the seizures in epileptic patients over the age of 50 was investigated and the frequency of seizures was analyzed regarding different age, gender, type of seizure and etiological groups. Method:  For this purpose, 387 patients were included in the study who were admitted to neurology outpatient clinic with the diagnosis of epilepsy. The patients are divided into groups based on those characteristics: male / female, generalized seizure / partial...

  10. An example of Ensemble Kalman Filter data assimilation in a Babcock-Leighton solar dynamo model

    Science.gov (United States)

    Dikpati, Mausumi; Anderson, Jeffrey L.

    2016-05-01

    Atmospheric and oceanic prediction models have been greatly advanced over the past 40 years by using modern data assimilation techniques. Application of similar techniques in solar models started about 7 years ago. However, acceptance of such techniques by the solar community has been slow to develop. In order to make accurate predictions of solar activity as well as reconstruction of certain model parameters that cannot be directly measured, it will be essential to implement sophisticated data assimilation techniques as used by atmospheric and oceanic models. We will present here an example of parameter reconstruction, namely the time variation in meridional flow-speed, done by assimilating data into a Babcock-Leighton solar dynamo model in the framework of NCAR's Data Assimilation Research Testbed (NCAR-DART). By performing many 'Observing System Simulation Experiments' (OSSEs) we find that an optimally good reconstruction in time series of meridional circulation can be obtained by using 16 ensemble members and assimilating one magnetic observation with less than 40 percent observational error. However, the RMS error in reconstruction reduces with increase in ensemble size, increase in number of observations and decrease in observational error. We also find that assimilation of magnetic field observations taken from low-to-mid latitudes at the surface compared to any other locations produces the best reconstruction. We will close by showing that assimilation cycle of 15 days is optimal; generally a longer assimilation cycle deteriorates the results, but the Dynamo DART system needs a minimum time to develop the dynamics.

  11. Development of a Chinese land data assimilation system: its progress and prospects

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The objective of land data assimilation is to merge multi-source observations into the dynamics of land surface model for improving the estimation of land surface states. We have developed a land data assimilation system for China's land territory. In this system, the Common Land Model and Simple Biosphere Model 2 are used to simulate land surface processes. The radiative transfer models of thawed and frozen soil, snow, lake, and vegetation are used as observation operators to transfer model predictions into estimated brightness temperatures. A Monte-Carlo based sequential filter, the ensemble Kalman filter, is implemented as data assimilation method to integrate modeling and observation. The system is capable of assimilating passive microwave remotely sensed data such as special sensor microwave/imager (SSM/I), TRMM microwave imager (TMI), and advanced microwave scanning radiometer enhanced for EOS (AMSRE) and the conventional in situ measurements of soil and snow. A spatiotemporally consistent assimilated dataset for soil moisture, soil temperature, snow and frozen soil, with a spatial resolution of 0.25 degree and temporal resolution of one hour, has been produced. This paper introduces the development of Chinese land data assimilation system and the progress made on data assimilation algorithms, land surface modeling, microwave remote sensing of land surface hydrological variables, and the preparation of atmospheric forcing data. The distinct characteristics and challenges of developing land data assimilation system and the perspectives for future development are also discussed .

  12. Psychogenic seizures in brain injury: diagnosis, treatment and case study.

    Science.gov (United States)

    Conder, R L; Zasler, N D

    1990-01-01

    Psychogenic seizures are a functional phenomena in which a person experiences a paroxysmal event that may be interpreted as epileptiform in nature. By definition, psychogenic seizures imply a sudden episode of change in behaviour or psychic state that is not associated with an identifiable process, either vasculogenic or neurogenic, and during which there is an absence of characteristic epileptiform changes on the electroencephalogram. Prevalence rates range from 5% to 50% in outpatient populations seen in epilepsy clinics. However, approximately 20% of true seizure patients also have psychogenic seizures. As psychogenic seizures are not a pathophysiological phenomena, pharmacological interventions do not alter their aetiology and can cloud the cognitive skills necessary to ameliorate the psychogenic seizure behaviour. In non-aphasic true seizure patients, as well as psychogenic seizure patients, self-control relaxation paradigms have been successful where pharmacological intervention has failed. This case involved an aphasic brain-injured patient who had both psychogenic and true seizures. For this patient, the self-control paradigm was modified to include use of gesture and prosody to achieve similar psychotherapeutic effects. Additionally, family therapy was instituted to provide a constructive means for the patient's family to participate in the reduction of psychogenic seizures. As seizures are a common sequelae of brain injury, the differential diagnosis of seizures and knowledge of standard and alternative treatment is essential for rehabilitation professionals. PMID:1701326

  13. Out-of-body experiences associated with seizures

    Directory of Open Access Journals (Sweden)

    Bruce eGreyson

    2014-02-01

    Full Text Available Alterations of consciousness are critical factors in the diagnosis of epileptic seizures. With these alterations in consciousness, some persons report sensations of separating from the physical body, experiences that may in rare cases resemble spontaneous out-of-body experiences. This study was designed to identify and characterize these out-of-body-like subjective experiences associated with seizure activity. 55% of the patients in this study recalled some subjective experience in association with their seizures. Among our sample of 100 patients, 7 reported out-of-body experiences associated with their seizures. We found no differentiating traits that were associated with patients’ reports of out-of-body experiences, in terms of either demographics; medical history, including age of onset and duration of seizure disorder, and seizure frequency; seizure characteristics, including localization, lateralization, etiology, and type of seizure, and epilepsy syndrome; or ability to recall any subjective experiences associated with their seizures. Reporting out-of-body experiences in association with seizures did not affect epilepsy-related quality of life. It should be noted that even in those patients who report out-of-body experiences, such sensations are extremely rare events that do not occur routinely with their seizures. Most patients who reported out-of-body experiences described one or two experiences that occurred an indeterminate number of years ago, which precludes the possibility of associating the experience with the particular characteristics of that one seizure or with medications taken or other conditions at the time.

  14. 28 CFR 0.86 - Seizure of gambling devices.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Seizure of gambling devices. 0.86 Section... Bureau of Investigation § 0.86 Seizure of gambling devices. The Director, Associate Director, Assistants... General to make seizures of gambling devices (18 U.S.C. 1955(d), 15 U.S.C. 1171 et seq.) and wire or...

  15. 8 CFR 1280.21 - Seizure of aircraft.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Seizure of aircraft. 1280.21 Section 1280... REGULATIONS IMPOSITION AND COLLECTION OF FINES § 1280.21 Seizure of aircraft. Seizure of an aircraft under the authority of section 239 of the Act and § 1280.2 will not be made if such aircraft is damaged to an...

  16. Seizure-like activity during fentanyl anesthesia. A case report.

    OpenAIRE

    Webb, M. D.

    1990-01-01

    Fentanyl induced seizures have been described previously in the literature. Clinical observations has labeled the movements seen in fentanyl anesthesia as seizure activity but electroencephalographic studies have not supported this. A case of seizure-like activity after the administration of fentanyl in a 20-year-old female is reported.

  17. Drug treatment-related factors of inadequate seizure control.

    NARCIS (Netherlands)

    Handoko, K.B.; Rijkom, JE Zwart-van; Visee, H.F.; Hermens, W.A.; Hekster, Y.A.; Egberts, T.C.G.

    2008-01-01

    To optimize seizure control it is important to identify modifiable factors. We conducted a case-control study to explore to what extent drug treatment-related factors are associated with seizures. Eighty-six patients with epilepsy were evaluated: 45 cases (recently experienced a seizure) and 41 cont

  18. Rapidly Learned Identification of Epileptic Seizures from Sonified EEG

    Directory of Open Access Journals (Sweden)

    Psyche eLoui

    2014-10-01

    Full Text Available Sonification refers to a process by which data are converted into sound, providing an auditory alternative to visual display. Currently, the prevalent method for diagnosing seizures in epilepsy is by visually reading a patient’s electroencephalogram (EEG. However, sonification of the EEG data provides certain advantages due to the nature of human auditory perception. We hypothesized that human listeners will be able to identify seizures from EEGs using the auditory modality alone, and that accuracy of seizure identification will increase after a short training session. Here we describe an algorithm we have used to sonify EEGs of both seizure and non-seizure activity, followed by a training study in which subjects listened to short clips of sonified EEGs and determine whether each clip was of seizure or normal activity, both before and after a short training session. Results show that before training subjects performed at chance level in differentiating seizures vs. non-seizures, but there was a significant improvement of accuracy after the training session. After training, subjects successfully distinguished seizures from non-seizures using the auditory modality alone. Further analyses using signal detection theory demonstrated improvement in sensitivity and reduction in response bias as a result of training. This study demonstrates the potential of sonified EEGs to be used for the detection of seizures. Future studies will attempt to increase accuracy using novel training and sonification modifications, with the goals of managing, predicting, and ultimately controlling seizures using sonification as a possible biofeedback-based intervention for epilepsy.

  19. Immunological perspectives of temporal lobe seizures.

    Science.gov (United States)

    Liimatainen, Suvi; Lehtimäki, Kai; Kai, Lehtimäki; Palmio, Johanna; Johanna, Palmio; Alapirtti, Tiina; Tiina, Alapirtti; Peltola, Jukka; Jukka, Peltola

    2013-10-15

    The temporal lobes are affected in many different neurological disorders, such as neurodegenerative diseases, viral and immunological encephalitides, and epilepsy. Both experimental and clinical evidence suggests a different inflammatory response to seizures in patients with temporal lobe epilepsy (TLE) in comparison to those with extra-TLE (XTLE). Proinflammatory cytokines and several autoantibodies have been shown to be associated with TLE compared to other epilepsy types suggesting the specific role and structure of the temporal lobe. Abundant experience suggests that activation of both innate and adaptive immunity is associated with epilepsy, particularly refractory focal epilepsy. Limbic encephalitis often triggers temporal lobe seizures, and a proportion of these disorders are immune-mediated. Histological evidence shows activation of specific inflammatory pathways in resected temporal lobes of epileptic patients, and certain epileptic disorders have shown increased incidence in patients with autoimmune diseases. Rapid activation of proinflammatory cytokines is observed after single seizures, but there is also evidence of chronic overproduction of cytokines and other inflammatory mediators in patients with TLE, suggesting a neuromodulatory role of inflammation in epilepsy. In this review we summarize current data on the presence and the role of immunological factors in temporal lobe seizures, and their possible involvement in epileptogenesis. PMID:23998423

  20. Seizures and Epilepsy in Sotos Syndrome

    OpenAIRE

    J Gordon Millichap

    2012-01-01

    Clinicians from the Child Neurology Division, Sapienza University of Rome, and 7 other pediatric neurology centers in Italy report a series of 19 Sotos syndrome (SS) patients with febrile seizures (FS) and/or epilepsy during childhood and a long-term follow-up.

  1. Cardiac arrhythmias during or after epileptic seizures.

    Science.gov (United States)

    van der Lende, Marije; Surges, Rainer; Sander, Josemir W; Thijs, Roland D

    2016-01-01

    Seizure-related cardiac arrhythmias are frequently reported and have been implicated as potential pathomechanisms of Sudden Unexpected Death in Epilepsy (SUDEP). We attempted to identify clinical profiles associated with various (post)ictal cardiac arrhythmias. We conducted a systematic search from the first date available to July 2013 on the combination of two terms: 'cardiac arrhythmias' and 'epilepsy'. The databases searched were PubMed, Embase (OVID version), Web of Science and COCHRANE Library. We attempted to identify all case reports and case series. We identified seven distinct patterns of (post)ictal cardiac arrhythmias: ictal asystole (103 cases), postictal asystole (13 cases), ictal bradycardia (25 cases), ictal atrioventricular (AV)-conduction block (11 cases), postictal AV-conduction block (2 cases), (post)ictal atrial flutter/atrial fibrillation (14 cases) and postictal ventricular fibrillation (3 cases). Ictal asystole had a mean prevalence of 0.318% (95% CI 0.316% to 0.320%) in people with refractory epilepsy who underwent video-EEG monitoring. Ictal asystole, bradycardia and AV-conduction block were self-limiting in all but one of the cases and seen during focal dyscognitive seizures. Seizure onset was mostly temporal (91%) without consistent lateralisation. Postictal arrhythmias were mostly found following convulsive seizures and often associated with (near) SUDEP. The contrasting clinical profiles of ictal and postictal arrhythmias suggest different pathomechanisms. Postictal rather than ictal arrhythmias seem of greater importance to the pathophysiology of SUDEP. PMID:26038597

  2. Electrical stimulation-induced models of seizures

    Czech Academy of Sciences Publication Activity Database

    Mareš, Pavel; Kubová, Hana

    Burlington: Academic Press, 2006 - (Pitkänen, A.; Schwartzkroin, P.; Moshé, S.), s. 153-159 ISBN 0-12-088554-9 Institutional research plan: CEZ:AV0Z50110509 Keywords : epilepsy * electroshock seizures Subject RIV: ED - Physiology

  3. Analysis of Epileptic Seizures with Complex Network

    Directory of Open Access Journals (Sweden)

    Yan Ni

    2014-01-01

    Full Text Available Epilepsy is a disease of abnormal neural activities involving large area of brain networks. Until now the nature of functional brain network associated with epilepsy is still unclear. Recent researches indicate that the small world or scale-free attributes and the occurrence of highly clustered connection patterns could represent a general organizational principle in the human brain functional network. In this paper, we seek to find whether the small world or scale-free property of brain network is correlated with epilepsy seizure formation. A mass neural model was adopted to generate multiple channel EEG recordings based on regular, small world, random, and scale-free network models. Whether the connection patterns of cortical networks are directly associated with the epileptic seizures was investigated. The results showed that small world and scale-free cortical networks are highly correlated with the occurrence of epileptic seizures. In particular, the property of small world network is more significant during the epileptic seizures.

  4. Targeting Pannexin1 Improves Seizure Outcome

    Science.gov (United States)

    Santiago, Marcelo F.; Veliskova, Jana; Patel, Naman K.; Lutz, Sarah E.; Caille, Dorothee; Charollais, Anne; Meda, Paolo; Scemes, Eliana

    2011-01-01

    Imbalance of the excitatory neurotransmitter glutamate and of the inhibitory neurotransmitter GABA is one of several causes of seizures. ATP has also been implicated in epilepsy. However, little is known about the mechanisms involved in the release of ATP from cells and the consequences of the altered ATP signaling during seizures. Pannexin1 (Panx1) is found in astrocytes and in neurons at high levels in the embryonic and young postnatal brain, declining in adulthood. Panx1 forms large-conductance voltage sensitive plasma membrane channels permeable to ATP that are also activated by elevated extracellular K+ and following P2 receptor stimulation. Based on these properties, we hypothesized that Panx1 channels may contribute to seizures by increasing the levels of extracellular ATP. Using pharmacological tools and two transgenic mice deficient for Panx1 we show here that interference with Panx1 ameliorates the outcome and shortens the duration of kainic acid-induced status epilepticus. These data thus indicate that the activation of Panx1 in juvenile mouse hippocampi contributes to neuronal hyperactivity in seizures. PMID:21949881

  5. Targeting pannexin1 improves seizure outcome.

    Directory of Open Access Journals (Sweden)

    Marcelo F Santiago

    Full Text Available Imbalance of the excitatory neurotransmitter glutamate and of the inhibitory neurotransmitter GABA is one of several causes of seizures. ATP has also been implicated in epilepsy. However, little is known about the mechanisms involved in the release of ATP from cells and the consequences of the altered ATP signaling during seizures. Pannexin1 (Panx1 is found in astrocytes and in neurons at high levels in the embryonic and young postnatal brain, declining in adulthood. Panx1 forms large-conductance voltage sensitive plasma membrane channels permeable to ATP that are also activated by elevated extracellular K(+ and following P2 receptor stimulation. Based on these properties, we hypothesized that Panx1 channels may contribute to seizures by increasing the levels of extracellular ATP. Using pharmacological tools and two transgenic mice deficient for Panx1 we show here that interference with Panx1 ameliorates the outcome and shortens the duration of kainic acid-induced status epilepticus. These data thus indicate that the activation of Panx1 in juvenile mouse hippocampi contributes to neuronal hyperactivity in seizures.

  6. Snow multivariable data assimilation for hydrological predictions in mountain areas

    Science.gov (United States)

    Piazzi, Gaia; Campo, Lorenzo; Gabellani, Simone; Rudari, Roberto; Castelli, Fabio; Cremonese, Edoardo; Morra di Cella, Umberto; Stevenin, Hervé; Ratto, Sara Maria

    2016-04-01

    The seasonal presence of snow on alpine catchments strongly impacts both surface energy balance and water resource. Thus, the knowledge of the snowpack dynamics is of critical importance for several applications, such as water resource management, floods prediction and hydroelectric power production. Several independent data sources provide information about snowpack state: ground-based measurements, satellite data and physical models. Although all these data types are reliable, each of them is affected by specific flaws and errors (respectively dependency on local conditions, sensor biases and limitations, initialization and poor quality forcing data). Moreover, there are physical factors that make an exhaustive reconstruction of snow dynamics complicated: snow intermittence in space and time, stratification and slow phenomena like metamorphism processes, uncertainty in snowfall evaluation, wind transportation, etc. Data Assimilation (DA) techniques provide an objective methodology to combine observational and modeled information to obtain the most likely estimate of snowpack state. Indeed, by combining all the available sources of information, the implementation of DA schemes can quantify and reduce the uncertainties of the estimations. This study presents SMASH (Snow Multidata Assimilation System for Hydrology), a multi-layer snow dynamic model, strengthened by a robust multivariable data assimilation algorithm. The model is physically based on mass and energy balances and can be used to reproduce the main physical processes occurring within the snowpack: accumulation, density dynamics, melting, sublimation, radiative balance, heat and mass exchanges. The model is driven by observed forcing meteorological data (air temperature, wind velocity, relative air humidity, precipitation and incident solar radiation) to provide a complete estimate of snowpack state. The implementation of an Ensemble Kalman Filter (EnKF) scheme enables to assimilate simultaneously ground

  7. Curcumin inhibits amygdaloid kindled seizures in rats

    Institute of Scientific and Technical Information of China (English)

    DU Peng; LI Xin; LIN Hao-jie; PENG Wei-feng; LIU Jian-ying; MA Yu; FAN Wei; WANG Xin

    2009-01-01

    Background Curcumin can reduce the severity of seizures induced by kainate acid (KA), but the role of curcumin in amygdaloid kindled models is still unknown. This study aimed to explore the effect of curcumin on the development of kindling in amygdaloid kindled rats.Methods With an amygdaloid kindled Sprague-Dawley (SD) rat model and an electrophysiological method, differentdoses of curcumin (10 mg·kg-1·d-1 and 30 mg·kg-1·d-1as low dose groups, 100 mg·kg-1·d-1 and 300 mg·kg-1·d-1 as high dose groups) were administrated intraperitoneally during the whole kindling days, by comparison with the course of kindling, afterdischarge (AD) thresholds and the number of Ads to reach the stages of class Ⅰ to Ⅴ seizures in the rats between control and experimental groups. One-way or two-way ANOVA and Fisher's least significant difference post hoc test were used for statistical analyses.Results Curcumin (both 100 mg·kg-1·d-1 and 300 mg·kg-1·d-1) significantly inhibited the behavioral seizure development in the (19.80±9.25) and (21.70±9.21) stimulations respectively required to reach the kindled state. Rats treated with 100 mg·kg-1·d-1 curcumin 30 minutes before kindling stimulation showed an obvious increase in the stimulation current intensity required to evoke AD from (703.3±85.9) μA to (960.0±116.5) μA during the progression to class Ⅴ seizures. Rats treated with 300 mg·kg-1·d-1 curcumin showed a significant increase in the stimulation current intensity required to evoke AD from (735.0±65.2) μA to (86±7.093.4) μA during the progression to class Ⅴ seizures. Rats treated with 300 mg·kg-1·d-1 curcumin required much more evoked Ads to reach the stage of class both Ⅳ (as (199.83±12.47) seconds) and Ⅴ seizures (as (210.66±10.68) seconds). Rats treated with 100 mg·kg-1·d-1 curcumin required much more evoked Ads to reach the stage of class V seizures (as (219.56±18.24) seconds). Conclusion Our study suggests that curcumin has a potential

  8. Assimilation of remote sensing observations into a sediment transport model of China's largest freshwater lake: spatial and temporal effects.

    Science.gov (United States)

    Zhang, Peng; Chen, Xiaoling; Lu, Jianzhong; Zhang, Wei

    2015-12-01

    Numerical models are important tools that are used in studies of sediment dynamics in inland and coastal waters, and these models can now benefit from the use of integrated remote sensing observations. This study explores a scheme for assimilating remotely sensed suspended sediment (from charge-coupled device (CCD) images obtained from the Huanjing (HJ) satellite) into a two-dimensional sediment transport model of Poyang Lake, the largest freshwater lake in China. Optimal interpolation is used as the assimilation method, and model predictions are obtained by combining four remote sensing images. The parameters for optimal interpolation are determined through a series of assimilation experiments evaluating the sediment predictions based on field measurements. The model with assimilation of remotely sensed sediment reduces the root-mean-square error of the predicted sediment concentrations by 39.4% relative to the model without assimilation, demonstrating the effectiveness of the assimilation scheme. The spatial effect of assimilation is explored by comparing model predictions with remotely sensed sediment, revealing that the model with assimilation generates reasonable spatial distribution patterns of suspended sediment. The temporal effect of assimilation on the model's predictive capabilities varies spatially, with an average temporal effect of approximately 10.8 days. The current velocities which dominate the rate and direction of sediment transport most likely result in spatial differences in the temporal effect of assimilation on model predictions. PMID:26199002

  9. FEBRILE SEIZURE: RECURRENCE AND RISK FACTORS

    Directory of Open Access Journals (Sweden)

    A. TALEBIAN

    2006-06-01

    Full Text Available Background:Febrile Convulsion is the most common convulsive disorder in children,occurring in 2 to 4% of the pediatric population and recurring in 30-50% of cases. Considering the varying recurrence rates reported, thisstudy was conducted at the pediatric ward of the Shaheed BeheshtiGeneral Hospital, between 2000-2001 to determine the frequencyof recurrence and related risk factors in children presenting with theirfirst episode of febrile convulsionMaterials & Methods:A two–year cohort study was performed on 50 children presentingwith the first attack of febrile convulsion. Patient demographic dataincluding age, sex, type and duration of seizure, family history offebrile seizure or epilepsy and the interval between fever onset andoccurrence of seizure were recorded in questionnaires. Those patients,for whom prophylactic medication was not administered, werefollowed at three–month intervals for up to one year. Findings werestatistically analyzed using Fisher’s exact testResults:Recurrence was observed in twelve children (24% out of the fifty,being most common in patients aged less than one year (54.4%.Recurrence rates among children with a positive family history offebrile convulsion, presence of complex febrile seizure and positivefamily history of epilepsy were 42.1%, 42.8% and 25% respectively.From among those children with a “less than one hour” intervalbetween fever onset and occurrence of seizure, recurrence occurredin 43-7% of cases, while in those with a “more than one hourinterval”, 14.7% experienced recurrence.Conclusion:Recurrence rates are increased by certain factors including age-belowone year-, positive family history of febrile convulsion, and a “lessthan one hour” interval between time of fever onset and seizureoccurrence.

  10. Evaluation of Seizure Attacks in Patients with Cerebrovascular Accident

    Directory of Open Access Journals (Sweden)

    Ebrahim Koochaki

    2013-04-01

    Full Text Available Background: The most common reason for seizure in elderly duration is the stroke. This study was conducted aiming to assess the frequency of seizure attack occurrence in those patients. Materials and Methods: This investigation was carried out through a cross-sectional method for one year on 330 patients admitted to the neurology ward as diagnosed with stroke. The required data was collected through the researcher-made questionnaire from the patients suffering from stoke which was diagnosed based on clinical findings, CT-Scan and MRI as required. Results: Among 330 patient suffering from stroke (162 men and 168 women, 48 cases (14.5% were suffering from seizure. Six percent of the patients had early seizure and another 8.5% had late seizure. Among 162 men suffering from the stroke, 32 ones were without seizures and 30 men were suffering the seizure. A number of 150 women out of total 168 ones suffering from the stroke, had no seizure and 18 others had seizures; frequency of seizure occurrence was more in male samples (p=0.044. In the people under 60 year, there were mostly early types of seizure (45% and in the age range above 60 year, it was mostly late type (89.3%. A 68.5% of the patients suffering from the seizure had experienced ischemic stroke. However, the frequency of seizure occurrence in the patients with hemorrhagic stroke was statistically greater (p=0.003. Conclusion: This examination showed that occurrence of seizure attacks in the people with stroke is 14.5% and it is seen more in the hemorrhagic strokes than ischemic ones. The frontoparietal area is the most common location involved and tonic clonic was the most common seizure in the patients suffering from it who have experienced the stroke

  11. Interictal spikes and epileptic seizures: their relationship and underlying rhythmicity.

    Science.gov (United States)

    Karoly, Philippa J; Freestone, Dean R; Boston, Ray; Grayden, David B; Himes, David; Leyde, Kent; Seneviratne, Udaya; Berkovic, Samuel; O'Brien, Terence; Cook, Mark J

    2016-04-01

    We report on a quantitative analysis of electrocorticography data from a study that acquired continuous ambulatory recordings in humans over extended periods of time. The objectives were to examine patterns of seizures and spontaneous interictal spikes, their relationship to each other, and the nature of periodic variation. The recorded data were originally acquired for the purpose of seizure prediction, and were subsequently analysed in further detail. A detection algorithm identified potential seizure activity and a template matched filter was used to locate spikes. Seizure events were confirmed manually and classified as either clinically correlated, electroencephalographically identical but not clinically correlated, or subclinical. We found that spike rate was significantly altered prior to seizure in 9 out of 15 subjects. Increased pre-ictal spike rate was linked to improved predictability; however, spike rate was also shown to decrease before seizure (in 6 out of the 9 subjects). The probability distribution of spikes and seizures were notably similar, i.e. at times of high seizure likelihood the probability of epileptic spiking also increased. Both spikes and seizures showed clear evidence of circadian regulation and, for some subjects, there were also longer term patterns visible over weeks to months. Patterns of spike and seizure occurrence were highly subject-specific. The pre-ictal decrease in spike rate is not consistent with spikes promoting seizures. However, the fact that spikes and seizures demonstrate similar probability distributions suggests they are not wholly independent processes. It is possible spikes actively inhibit seizures, or that a decreased spike rate is a secondary symptom of the brain approaching seizure. If spike rate is modulated by common regulatory factors as seizures then spikes may be useful biomarkers of cortical excitability.media-1vid110.1093/brain/aww019_video_abstractaww019_video_abstract. PMID:26912639

  12. Assimilate partitioning during reproductive growth

    International Nuclear Information System (INIS)

    Leaves having various phyllotactic relationships to fruitlets were labeled for 1 hour with 10/sub r/Ci of 14CO2. Fruitlets were also labeled. Fruitlets did fix 14CO2. Translocation of radioactivity from the peel into the fruit occurred slowly and to a limited extent. No evidence of translocation out of the fruitlets was observed. Assimilate partitioning in avocado was strongly influenced by phyllotaxy. If a fruit and the labeled leaf had the same phyllotaxy then greater than 95% of the radiolabel was present in this fruit. When the fruit did not have the same phyllotaxy as the labeled leaf, the radiolabel distribution was skewed with 70% of the label going to a single adjacent position. Avocado fruitlets exhibit uniform labeling throughout a particular tissue. In avocado, assimilates preferentially move from leaves to fruits with the same phyllotaxy

  13. Assimilation, Criminality and Ethnic Conflict

    OpenAIRE

    Dasgupta, Indraneel; Mukherjee, Diganta

    2014-01-01

    We examine the consequences, of integrating large minorities into productivity-relevant majority ethno-linguistic norms, for distribution, ethnic conflict and crime. We develop a two-community model where such assimilation generates social gains by: (a) facilitating economic interaction, and (b) dampening religious or racial conflict over symbolic and normative contents of the public sphere. However, integration shifts the distribution of both material and symbolic goods against the minority....

  14. Financial assimilation of immigrants conference

    OpenAIRE

    anonymous

    2003-01-01

    On June 24, the Consumer and Community Affairs division of the Federal Reserve Bank of Chicago convened, “An Informed Discussion of the Financial Assimilation of Immigrants” in Des Moines, Iowa. The conference was part of the larger, long-term program by the Chicago Reserve Bank to study the ways and means by which immigrants to the United States access mainstream financial services. This Special Edition of PNV comprises summaries of each of the conference presentations.

  15. An open framework for hydrological data assimilation

    Science.gov (United States)

    Madsen, H.; Ridler, M. E.; Velzen, N. V.; Hummel, S.; Sandholt, I.; Falk, A. K.; Heemink, A.

    2013-12-01

    Accurate and reliable real-time hydrological forecasts are essential for protection against water-related hazards, operation of infrastructure, and water resources management. Recent advances in radar rainfall estimation and forecasting, numerical weather predictions, satellite and in-situ monitoring, and faster computing facilities are opening up new opportunities in real-time hydrological forecasting. More effective use of the different information sources via data assimilation will provide the basis for producing more accurate and more reliable forecasts. In this regard, development and implementation of robust and computationally efficient data assimilation algorithms that are feasible for real-time applications remains one of the key challenges. Thus far, many of the efforts on implementation of data assimilation in hydrological modeling have been model specific. This requires access to as well as an in-depth knowledge of the numerical core of the models. A means to deal with the interaction between model and data assimilation algorithm in a more generic way is the use of the Open Model Interface (OpenMI). This open source standard interface allows models to exchange data during runtime, thus transforming a complex numerical model to a plug and play like component. For data assimilation, the OpenDA data assimilation toolbox is an open interface standard that includes a set of tools, assimilation algorithms, and numerical techniques to quickly implement data assimilation in numerical models. This paper presents a new generic data assimilation framework that uses OpenMI to interface models within OpenDA. This enables the many OpenMI hydrological models already available access to a robust and flexible data assimilation library. A synthetic test case is presented that highlights the potential of this new framework. An ensemble based Kalman filter is demonstrated for assimilation of groundwater levels in the MIKE SHE distributed and integrated hydrological

  16. Analysis of the Martian ozone cycle by assimilation of SPICAM observations

    OpenAIRE

    Holmes, J. A.; Lewis, S. R.; Patel, M.R.; Lefèvre, F.; Forget, F.

    2013-01-01

    Observations of ozone, a trace gas on Mars, have the potential to constrain atmospheric dynamical and physical processes. Current Mars Global Circulation Models (MGCMs) are able to represent the photochemistry occuring in the atmosphere, with comparisons to observations used to confine particular species. However, a long term comparison using data assimilation provides a more robust constraint on the model. We have assimilated total-ozone observations from SPICAM into an MGCM to study the Mar...

  17. SEIZURE SEVERITY AS AN ALTERNATIVE MEASURE OF OUTCOME IN EPILEPSY

    Directory of Open Access Journals (Sweden)

    Koraliya S. Todorova

    2013-07-01

    Full Text Available Seizure severity emerges as an important aspect of epilepsy. This is most relevant in refractory patients in whom complete remission of seizures is unlikely and reduced seizure severity may be a significant determinant of psychosocial well-being with a consequent improvement in quality of life (QOL. Thus a valid measure of seizure severity can serve both as an indicator of clinical outcome and as an evaluation tool of the interaction between seizures and the psychosocial complications of epilepsy.After a brief review of the most frequently used scales measuring seizure severity in adults with epilepsy we have explored the relationship between seizure severity and QOL in a set of 103 patients. Two self-evaluation questionnaires were applied: the Seizure Severity Questionnaire (SSQ and the Quality of Life in Epilepsy Inventory (QOLIE-31. The severity of the coexisting depression, an important confounder in the relationship between seizure severity and QOL, was assessed by the Hamilton Depression Rating Scale (HAMD-17.All domains of the Quality-of-Life in Epilepsy Inventory (QOLIE-31 correlated highly significantly with seizure severity (p≤0.01. The correlation was strong for the Overall score (r=-0.70; p≤0.001 and the Seizure worry domain (r=-0.71; p≤0.001. When the potentially confounding effect of depression was controlled for, the regression of seizure severity with the QOLIE-31 Overall score (P=0.001; R²=0.56 and the Seizure worry domain (P=0.001; R²=0.50 remained significant. These findings indicate that seizure severity is strongly associated with QOL in epilepsy and could be used as an alternative indicator of outcome in clinical research.

  18. Impact of assimilation window length on diurnal features in a Mars atmospheric analysis

    Directory of Open Access Journals (Sweden)

    Yongjing Zhao

    2015-05-01

    Full Text Available Effective simulation of diurnal variability is an important aspect of many geophysical data assimilation systems. For the Martian atmosphere, thermal tides are particularly prominent and contribute much to the Martian atmospheric circulation, dynamics and dust transport. To study the Mars diurnal variability and Mars thermal tides, the Geophysical Fluid Dynamics Laboratory Mars Global Climate Model with the 4D-local ensemble transform Kalman filter (4D-LETKF is used to perform an analysis assimilating spacecraft temperature retrievals. We find that the use of a ‘traditional’ 6-hr assimilation cycle induces spurious forcing of a resonantly enhanced semi-diurnal Kelvin waves represented in both surface pressure and mid-level temperature by forming a wave 4 pattern in the diurnal averaged analysis increment that acts as a ‘topographic’ stationary forcing. Different assimilation window lengths in the 4D-LETKF are introduced to remove the artificially induced resonance. It is found that short assimilation window lengths not only remove the spurious resonance, but also push the migrating semi-diurnal temperature variation at 50 Pa closer to the estimated ‘true’ tides even in the absence of a radiatively active water ice cloud parameterisation. In order to compare the performance of different assimilation window lengths, short-term to mid-range forecasts based on the hour 00 and 12 assimilation are evaluated and compared. Results show that during Northern Hemisphere summer, it is not the assimilation window length, but the radiatively active water ice clouds that influence the model prediction. A ‘diurnal bias correction’ that includes bias correction fields dependent on the local time is shown to effectively reduce the forecast root mean square differences between forecasts and observations, compensate for the absence of water ice cloud parameterisation and enhance Martian atmosphere prediction. The implications of these results for

  19. Ensemble Data Assimilation: Algorithms and Software

    OpenAIRE

    Nerger, Lars

    2014-01-01

    Ensemble data assimilation is nowadays applied to various problems to estimate a model state and model parameters by combining the model predictions with observational data. At the Alfred Wegener Institute, the assimilation focuses on ocean-sea ice models and coupled ocean-biogeochemical models. The high dimension of realistic models requires particularly efficient algorithms that are also usable on supercomputers. For the application of such filters, the Parallel Data Assimilation Framework ...

  20. Assimilation and integration of immigrants in Europe

    OpenAIRE

    Aleksynska, Mariya; ALGAN, Yann

    2010-01-01

    This paper documents assimilation of immigrants in European destinations along cultural, civic, and economic dimensions, distinguishing by immigrants' generation, duration of stay, and origin. Based on the European Social Survey, it suggests that assimilation may have multiple facets, and take place at different speed depending on the outcome in question. While assimilation along some economic and cultural outcomes may be correlated, such correlations are not systematic, and imply that progre...

  1. Outline of an Economic Theory of Assimilation

    OpenAIRE

    Schaeffer, Peter V.

    2006-01-01

    In an age of mass immigration, assimilation is critical not only to the success of the immigrants but also to the success of their descendants and of the host society. This paper presents an outline for an economic theory of assimilation based on the assumption that both immigrants and natives invest in assimilation, that both may in fact move in the direction of the "other," and that the notion of "distance" is subjective and reversible.

  2. Immigrant Job Search Assimilation in Canada

    OpenAIRE

    Bowlus, Audra J.; Miyairi, Masashi; Robinson, Chris

    2013-01-01

    Immigrant assimilation is a major issue in many countries. While most of the literature studies assimilation through a human capital framework, we examine the role of job search assimilation. To do so, we estimate an equilibrium search model of immigrants operating in the same labor market as natives, where newly arrived immigrants have lower job offer arrival rates than natives but can acquire the same arrival rates according to a stochastic process. Using Canadian panel data, we find substa...

  3. Phenobarbitone versus phenytoin monotherapy for partial onset seizures and generalized onset tonic-clonic seizures

    Science.gov (United States)

    Taylor, Stephen; Smith, Catrin Tudur; Williamson, Paula R; Marson, Anthony G

    2014-01-01

    Background This is an updated version of the original Cochrane review published in Issue 4, 2001. Worldwide, phenytoin and phenobarbitone are commonly used antiepileptic drugs. They are more likely to be used in the developing world than the developed world, primarily because they are inexpensive. The aim of this review is to summarize data from existing trials comparing phenytoin and phenobarbitone. Objectives To review the effects of phenobarbitone compared to phenytoin when used as monotherapy in patients with partial onset seizures or generalized tonic-clonic seizures with or without other generalized seizure types. Search methods We searched the Cochrane Epilepsy Group trials register (20 October 2009), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2009) and MEDLINE (1950 to October week 2, 2009). In addition, we handsearched relevant journals, and contacted pharmaceutical companies and researchers in the field to seek any ongoing or unpublished studies. Selection criteria Randomized controlled trials in children or adults with partial onset seizures or generalized onset tonic-clonic seizures. Trials must have included a comparison of phenobarbitone monotherapy with phenytoin monotherapy. Data collection and analysis This was an individual patient data review. Outcomes were time to (a) withdrawal of allocated treatment, (b) 12-month remission and (c) first seizure post randomization. Data were analyzed using a stratified logrank analysis with results expressed as hazard ratios (HR) and 95% confidence intervals (95% CI), where a HR > 1 indicates an event is more likely to occur earlier on phenobarbitone than phenytoin. Main results To date, data have been obtained for four of ten studies meeting the inclusion criteria, amounting to 599 individuals, or approximately 65% of the potential data. The main overall results (HR) were (a) time to treatment withdrawal 1.62 (95% confidence interval 1.22 to 2.14); (b) time to 12-month

  4. Physics of the Brain: Interaction of the Optical-Fiber-Guided Multi-Ultraviolet-Photon Beams with the Epilepsy Topion, (the Seizure Onset Area)

    Science.gov (United States)

    Stefan, V. Alexander

    A novel method for the possible prevention of epileptic seizures is proposed, based on the multi-ultraviolet-photon beam interaction with the epilepsy topion, (nonlinear coupling of an ultra high frequency mode to the brain beta phonons). It is hypothesized that epilepsy is a chaotic-dynamics phenomenon: small electrical changes in the epilepsy-topion lead, (within the 10s of milliseconds), to the onset of chaos, (seizure--excessive electrical discharge), and subsequent cascading into adjacent areas. The ultraviolet photons may control the imbalance of sodium and potassium ions and, consequently, may prove to be efficient in the prevention of epileptic seizures. Supported by Nikola Tesla Labs, Stefan University.

  5. The Presence of Consciousness in Absence Seizures

    OpenAIRE

    Bayne, Tim

    2011-01-01

    This paper examines three respects in which the study of epileptic absence seizures promises to inform our understanding of consciousness. Firstly, it has the potential to bear on debates concerning the behavioural and cognitive functions associated with consciousness. Secondly, it has the potential to illuminate the relationship between background states (or ‘levels’) of consciousness and the contents of consciousness. Thirdly, it has the potential to bear on our understanding of the unity o...

  6. Searches and Seizures in a Networked World

    OpenAIRE

    Zittrain, Jonathan L.

    2006-01-01

    This essay responds to Orin S. Kerr, Searches and Seizures in a Digital World, 119 Harv. L. Rev. 531 (2005), http://ssrn.com/abstract=697541. Professor Kerr has published a thorough and careful article on the application of the Fourth Amendment to searches of computers in private hands - a treatment that has previously escaped the attentions of legal academia. Such a treatment is perhaps so overdue that it has been overtaken by two phenomena: first, the emergence of an overriding concern...

  7. Seizures After Overdoses of Bupropion Intake

    OpenAIRE

    Kara, Hasan; AK, Ahmet; Bayır, Ayşegül; Acar, Demet; İstanbulluoğlu, Rabia; Değirmenci, Selim

    2013-01-01

    Background: Bupropion is a new-generation monocyclic antidepressant that has been accidentally found to have potential effects on reducing nicotine addiction. It is structurally similar to stimulants such as amphetamine and inhibits dopamine and noradrenalin reuptake selectively. Case Reports: We report two cases with no history of epilepsy who took oral bupropion for depression and had generalised tonic-clonic type of seizures in their follow-ups. Conclusion: After an ov...

  8. A gut feeling about insular seizures

    OpenAIRE

    Dionisio, S; A. Koenig; Murray, J.; Somerville, E

    2011-01-01

    A 43-year-old man presented to the Prince of Wales Hospital, Sydney, New South Wales, Australia, after experiencing his first tonic-clonic seizure. For the previous 2 years he had undergone gastroenterological investigation of episodes of gagging associated with hypersalivation and lachrymation, occurring three or four times per week. EEG showed epileptiform discharges in the right anterior temporal region; brain MRI revealed a lesion in the right insular cortex. Video-EEG telemetry demonstra...

  9. Seizure Following Topical Gammabenzene Hexachloride Therapy

    Directory of Open Access Journals (Sweden)

    Biswas Animesh

    2002-01-01

    Full Text Available Development of short-lived, self-limiting major epileptic seizures following an improper application of gammabenzene hexachloride (GBHC lotion in a 15 month old boy suffering from scabies with secondary bacterial infection is reported here due to its rarity in clinical practice and, more particularly, to stress the need of correct instructions on the use of GBHC application for the prevention of iatrogenic neurotoxicity.

  10. A virtual reality catchment for data assimilation experiments

    Science.gov (United States)

    Schalge, Bernd; Rihani, Jehan; Haese, Barbara; Baroni, Gabriele; Erdal, Daniel; Neuweiler, Insa; Hendricks-Franssen, Harrie-Jan; Geppert, Gernot; Ament, Felix; Kollet, Stefan; Cirpka, Olaf; Saavedra, Pablo; Han, Xujun; Attinger, Sabine; Kunstmann, Harald; Vereecken, Harry; Simmer, Clemens

    2016-04-01

    Current data assimilation (DA) systems often lack the possibility to assimilate measurements across compartments to accurately estimate states and fluxes in subsurface-land surface-atmosphere systems (SLAS). In order to develop a new DA framework that is able to realize this cross-compartmental assimilation a comprehensive testing environment is needed. Therefore a virtual reality (VR) catchment is constructed with the Terrestrial System Modeling Platform (TerrSysMP). This catchment mimics the Neckar catchment in Germany. TerrSysMP employs the atmospheric model COSMO, the land surface model CLM and the hydrological model ParFlow coupled with the external coupler OASIS. We will show statistical tests to prove the plausibility of the VR. The VR is running in a fully-coupled mode (subsurface - land surface - atmosphere) which includes the interactions of subsurface dynamics with the atmosphere, such as the effects of soil moisture, which can influence near-surface temperatures, convection patterns or the surface heat fluxes. A reference high resolution run serves as the "truth" from which virtual observations are extracted with observation operators like virtual rain gauges, synoptic stations and satellite observations (amongst others). This effectively solves the otherwise often encountered data scarcity issues with respect to DA. Furthermore an ensemble of model runs at a reduced resolution is performed. This ensemble serves also for open loop runs to be compared with data assimilation experiments. The model runs with this ensemble served to identify sets of parameters that are especially sensitive to changes and have the largest impact on the system. These parameters were the focus of subsequent ensemble simulations and DA experiments. We will show to what extend the VR states can be re-constructed using data assimilation methods with only a limited number of virtual observations available.

  11. Ictal alterations of consciousness during ecstatic seizures.

    Science.gov (United States)

    Picard, Fabienne; Kurth, Florian

    2014-01-01

    Patients with ecstatic epileptic seizures report an altered consciousness, which they describe as a sense of heightened perception of themselves – they “feel very present” – and an increased vividness of sensory perceptions. Recently, the anterior insula has been proposed as the region where these seizures originate, based on the results of ictal nuclear imaging in three patients, the first induction of ecstatic auras by electrical stimulation, and the functional characteristics of the anterior insula in neuroimaging literature. Specifically, the anterior insula is thought to play a key role in integrating information from within the body, the external world, as well as the emotional states. In addition, the anterior insula is thought to convert this integrated information into successive global emotional moments, thus enabling both the construct of a sentient self as well as a mechanism for predictive coding. As part of the salience network, this region is also involved in switching from mind wandering toward attentional and executive processing. In this review, we will summarize previous patient reports and recap how insular functioning may be involved in the phenomenon of ecstatic seizures. Furthermore, we will relate these hypotheses to the results from research on meditation and effects of drug abuse. PMID:24436968

  12. Eslicarbazepine acetate for partial-onset seizures.

    Science.gov (United States)

    Rauchenzauner, Markus; Luef, Gerhard

    2011-12-01

    Eslicarbazepine acetate (ESL), a new voltage-gated sodium channel blocker that is chemically related to carbamazepine and partially metabolized to oxcarbazepine, has attracted attention as results of previous Phase II and III studies demonstrated and confirmed efficacy and tolerability of ESL 800 and 1200 mg once daily as add-on therapy for adult patients with drug-resistant partial-onset seizures. In children, efficacy data point towards a dose-dependent decrease in seizure frequency and tolerability analyses showed a low incidence of mild drug-related adverse effects at 5 and 15 mg/kg/day. The most frequently reported adverse effects were dizziness, somnolence, headache, diplopia, nausea and vomiting. The convenience of once-daily dosing and a short/simple titration regimen in combination with a comparative efficacy and tolerability profile might promote ESL as a valid alternative to the current adjunctive antiepileptic drug therapy armamentarium for drug-resistant partial seizures in adults. Since clinical trials in children and adolescents on ESL efficacy and safety are ongoing and data already published are far from conclusive, the therapeutic value of ESL in this special population has to be established in the near future. PMID:22091592

  13. Towards Operational Data Assimilation in the North and Baltic Seas with the Parallel Data Assimilation Framework

    OpenAIRE

    Nerger, Lars; Loza, Svetlana; Schröter, Jens; Hiller, Wolfgang; F. Janssen

    2010-01-01

    Within the GMES-related project DeMarine Environment, the operational circulation model of the German Maritime and Hydrographic Agency (BSH) is extended into a data assimilation system. The aim of the data assimilation is to improve the forecast of sea surface height, temperatura, currents and salinity in the North and Baltic Seas. For the data assimilation component, the Parallel Data Assimilation Framework (PDAF, http://pdaf.awi.de) is coupled to the operational circulation model. PDAF prov...

  14. Altimeter data assimilation in the tropical Indian Ocean using water property conserving scheme

    Indian Academy of Sciences (India)

    Bhasha M Mankad; Rashmi Sharma; Sujit Basu; P K Pal

    2012-02-01

    Altimeter data have been assimilated in an ocean general circulation model using the water property conserving scheme. Two runs of the model have been conducted for the year 2004. In one of the runs, altimeter data have been assimilated sequentially, while in another run, assimilation has been suppressed. Assimilation has been restricted to the tropical Indian Ocean. An assessment of the strength of the scheme has been carried out by comparing the sea surface temperature (SST), simulated in the two runs, with in situ derived as well as remotely sensed observations of the same quantity. It has been found that the assimilation exhibits a significant positive impact on the simulation of SST. The subsurface effect of the assimilation could be judged by comparing the model simulated depth of the 20°C isotherm (hereafter referred to as D20), as a proxy of the thermocline depth, with the same quantity estimated from ARGO observations. In this case also, the impact is noteworthy. Effect on the dynamics has been judged by comparison of simulated surface current with observed current at a moored buoy location, and finally the impact on model sea level forecast in a free run after assimilation has been quantified in a representative example.

  15. Impacts of physical data assimilation on the Global Ocean Carbonate System

    Directory of Open Access Journals (Sweden)

    L. Visinelli

    2014-04-01

    Full Text Available Prognostic simulations of ocean carbon distribution are largely dependent on an adequate representation of physical dynamics. In this work we show that the assimilation of temperature and salinity in a coupled ocean-biogeochemical model significantly improves the reconstruction of the carbonate system variables over the last two decades. For this purpose, we use the NEMO ocean global circulation model, coupled to the Biogeochemical Flux Model (BFM in the global PELAGOS configuration. The assimilation of temperature and salinity is included into the coupled ocean-biogeochemical model by using a variational assimilation method. The use of ocean physics data assimilation improves the simulation of alkalinity and dissolved organic carbon against the control run as assessed by comparing with independent time series and gridded datasets. At the global scale, the effects of the assimilation of physical variables in the simulation of pCO2 improves the seasonal cycle in all basins, getting closer to the SOCAT estimates. Biases in the partial pressure of CO2 with respect to data that are evident in the control run are reduced once the physical data assimilation is used. The root mean squared errors in the pCO2 are reduced by up to 30% depending on the ocean basin considered. In addition, we quantify the relative contribution of biological carbon uptake on surface pCO2 by performing another simulation in which biology is neglected in the assimilated run.

  16. Perspectives on seizure clusters: Gaps in lexicon, awareness, and treatment.

    Science.gov (United States)

    Buelow, Janice M; Shafer, Patricia; Shinnar, Ruth; Austin, Joan; Dewar, Sandra; Long, Lucretia; O'Hara, Kathryn; Santilli, Nancy

    2016-04-01

    Seizure clusters in epilepsy can result in serious outcomes such as missed work or school, postictal psychosis, emergency room visits, or hospitalizations, and yet they are often not included in discussions between health-care professionals (HCPs) and their patients. The purpose of this paper was to describe and compare consumer (patient and caregivers) and professional understanding of seizure clusters and to describe how consumers and HCPs communicate regarding seizure clusters. We reviewed social media discussion sites to explore consumers' understanding of seizure clusters. We analyzed professional (medical) literature to explore the HCPs' understanding of seizure clusters. Major themes were revealed in one or both groups, including: communication about diagnosis; frequency, duration, and time frame; seizure type and pattern; severity; and self-management. When comparing discussions of professionals and consumers, both consumers and clinicians discussed the definition of seizure clusters. Discussions of HCPs were understandably clinically focused, and consumer discussions reflected the experience of seizure clusters; however, both groups struggled with a common lexicon. Seizure cluster events remain a problem associated with serious outcomes. Herein, we outline the lack of a common understanding and recommend the development of a common lexicon to improve communication regarding seizure clusters. PMID:26906403

  17. Post-stroke seizures in consecutive elderly stroke patients

    Institute of Scientific and Technical Information of China (English)

    Yue Chen; Lufang Chen; Yiqing Tao; Maomao Han; Chunlan Cui; Shichao Liu

    2011-01-01

    This prospective study sought to investigate the clinical, radiological and electroencephalographic (EEG) characteristics of seizures in elderly stroke patients, and their outcomes. Over a 2-year study period, 158 consecutive eldedy patients with stroke were examined and followed up. Of these patients, 32 (20%) developed seizures, primarily related to stroke, within a follow up period between 5 months and 2 years. Of these 32 cases, 20 experienced infarctions, and 12 experienced hemorrhages. Involvement of cortical regions was detected in most of the patients exhibiting seizures. In these patients, 44% of the lesions involved cortical areas exclusively or in addition to subcortical areas observed on computed tomography (CT) images. Twenty-five patients (78%)developed early seizures (within 2 weeks after stroke), and half exhibited immediate post-stroke seizures. None of the patients exhibiting early onset seizures developed recurrent seizures or epilepsy, while 57% of late onset seizures (four cases) developed epilepsy. No specific EEG patterns were apparent in those who later developed epilepsy. Overall, early onset seizures after stroke were found to be relatively common, and did not affect outcome. Late onset seizures were less common, but were associated with chronic epilepsy.

  18. Epileptic seizures in patients with a posterior circulation infarct

    Directory of Open Access Journals (Sweden)

    Yüksel Kaplan

    2014-08-01

    Full Text Available OBJECTIVE: The aim of this study was to investigate the frequency of seizures and the clinical features of patients with seizures related to a posterior circulation infarct (POCI. METHODS: We reviewed all ischemic stroke patients admitted to our clinic between January 2011 and January 2012. The patients’ database information was retrospectively analyzed. Fifty-five patients with a POCI were included in the study. We reviewed all patients with epileptic seizures related to a POCI. Age, gender, recurrent stroke, risk factors, etiology, radiographic localization, the seizure type and onset time, and the electroencephalographic findings of patients were evaluated. We excluded all patients who had precipitating conditions during seizures such as taking drugs, acid-base disturbances, electrolyte imbalance, and history of epilepsy. RESULTS: Seizures were observed in four patients (3 male, 1 female with a POCI related epileptic seizures (7.2%. The etiology of strokes was cardiac-embolic in 3 patients and vertebral artery dissection in 1 patient. Seizures occurred in 2 patients as presenting finding, in 1 patient within 7 days, and 1 patient within 28 days. Primary generalized tonic-clonic seizures occurred in 3 patients and simple partial seizures with secondary generalization in 1 patient. Three patients had cerebellum infarction at the left hemisphere. One patient had lateral medullary infarction at the right side. The electroencephalographic findings of patients were normal. CONCLUSION: Studies involving patients with seizures related to a POCI are novel and few in number. Three patients with seizure had cerebellum infarction. The cerebellum in these patients may contribute via different mechanisms over seizure activity.

  19. Compensation for Complete Assimilation in Speech Perception: The Case of Korean Labial-to-Velar Assimilation

    Science.gov (United States)

    Mitterer, Holger; Kim, Sahyang; Cho, Taehong

    2013-01-01

    In connected speech, phonological assimilation to neighboring words can lead to pronunciation variants (e.g., "garden bench" [arrow right] "garde'm' bench"). A large body of literature suggests that listeners use the phonetic context to reconstruct the intended word for assimilation types that often lead to incomplete assimilations (e.g., a…

  20. A data assimilation methodology for reconstructing turbulent flows around aircraft

    Science.gov (United States)

    Kato, Hiroshi; Yoshizawa, Akira; Ueno, Genta; Obayashi, Shigeru

    2015-02-01

    This paper proposes a new approach for the study of complex turbulent flows of aeronautics that integrates experimental fluid dynamics (EFD), employing methods such as wind tunnel experiments, and computational fluid dynamics (CFD) by using a data assimilation technique. The approach aims at representing complex turbulent flows more properly than conventional EFD and CFD approaches by estimating the proper angle of attack, the proper Mach number, and the proper turbulent viscosity, which are the three uncertainty factors in EFD and CFD. To this end, the ensemble transform Kalman filter (ETKF), a sequential advanced data assimilation method, is employed for the estimation and applied to transonic flows around the RAE 2822 airfoil (two-dimensional flow) and transonic flows around the ONERA M6 wing (three-dimensional flow). The results computed using the angles of attack, Mach numbers, and turbulent viscosities estimated by the ETKF diminish the discrepancies between the results of standard computations and experiments. These findings show the effectiveness of this approach, which combines EFD and CFD using data assimilation to represent complex turbulent flows.

  1. Data assimilation with inequality constraints

    Science.gov (United States)

    Thacker, W. C.

    If values of variables in a numerical model are limited to specified ranges, these restrictions should be enforced when data are assimilated. The simplest option is to assimilate without regard for constraints and then to correct any violations without worrying about additional corrections implied by correlated errors. This paper addresses the incorporation of inequality constraints into the standard variational framework of optimal interpolation with emphasis on our limited knowledge of the underlying probability distributions. Simple examples involving only two or three variables are used to illustrate graphically how active constraints can be treated as error-free data when background errors obey a truncated multi-normal distribution. Using Lagrange multipliers, the formalism is expanded to encompass the active constraints. Two algorithms are presented, both relying on a solution ignoring the inequality constraints to discover violations to be enforced. While explicitly enforcing a subset can, via correlations, correct the others, pragmatism based on our poor knowledge of the underlying probability distributions suggests the expedient of enforcing them all explicitly to avoid the computationally expensive task of determining the minimum active set. If additional violations are encountered with these solutions, the process can be repeated. Simple examples are used to illustrate the algorithms and to examine the nature of the corrections implied by correlated errors.

  2. Data Assimilation - Advances and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Brian J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-07-30

    This presentation provides an overview of data assimilation (model calibration) for complex computer experiments. Calibration refers to the process of probabilistically constraining uncertain physics/engineering model inputs to be consistent with observed experimental data. An initial probability distribution for these parameters is updated using the experimental information. Utilization of surrogate models and empirical adjustment for model form error in code calibration form the basis for the statistical methodology considered. The role of probabilistic code calibration in supporting code validation is discussed. Incorporation of model form uncertainty in rigorous uncertainty quantification (UQ) analyses is also addressed. Design criteria used within a batch sequential design algorithm are introduced for efficiently achieving predictive maturity and improved code calibration. Predictive maturity refers to obtaining stable predictive inference with calibrated computer codes. These approaches allow for augmentation of initial experiment designs for collecting new physical data. A standard framework for data assimilation is presented and techniques for updating the posterior distribution of the state variables based on particle filtering and the ensemble Kalman filter are introduced.

  3. Detection of Epilepsy from EEG Signal during Seizure Using Entropy-Based Fuzzy c-Means

    Directory of Open Access Journals (Sweden)

    Tahir Ahmad

    2012-09-01

    Full Text Available One of the major roles of Electrocephalography (EEG is an aid to diagnose epilepsy. Abnormal patterns such as spikes, sharp wave complexes can be seen. Our main interest is to extract information about the dynamics from a few observations of this record signal. In this study, the entropy-based fuzzy c-Means is used to cluster EEG signal of patients during an epileptic seizure.We obtained signatures of general epilepsy by superimposing results of the method.

  4. Data Assimilation by Conditioning of Driving Noise on Future Observations

    KAUST Repository

    Lee, Wonjung

    2014-08-01

    Conventional recursive filtering approaches, designed for quantifying the state of an evolving stochastic dynamical system with intermittent observations, use a sequence of i) an uncertainty propagation step followed by ii) a step where the associated data is assimilated using Bayes\\' rule. Alternatively, the order of the steps can be switched to i) one step ahead data assimilation followed by ii) uncertainty propagation. In this paper, we apply this smoothing-based sequential filter to systems driven by random noise, however with the conditioning on future observation not only to the system variable but to the driving noise. Our research reveals that, for the nonlinear filtering problem, the conditioned driving noise is biased by a nonzero mean and in turn pushes forward the filtering solution in time closer to the true state when it drives the system. As a result our proposed method can yield a more accurate approximate solution for the state estimation problem. © 1991-2012 IEEE.

  5. Advanced Data Assimilation for Geosciences : Lecture Notes of the Les Houches School of Physics

    CERN Document Server

    Bocquet, Marc; Cosme, Emmanuel; Cugliandolo, Leticia F

    2014-01-01

    This book gathers notes from lectures and seminars given during a three-week school on theoretical and applied data assimilation held in Les Houches in 2012. Data assimilation aims at determining as accurately as possible the state of a dynamical system by combining heterogeneous sources of information in an optimal way. Generally speaking, the mathematical methods of data assimilation describe algorithms for forming optimal combinations of observations of a system, a numerical model that describes its evolution, and appropriate prior information. Data assimilation has a long history of application to high-dimensional geophysical systems dating back to the 1960s, with application to the estimation of initial conditions for weather forecasts. It has become a major component of numerical forecasting systems in geophysics, and an intensive field of research, with numerous additional applications in oceanography and atmospheric chemistry, with extensions to other geophysical sciences. The physical complexity and ...

  6. Downscaling wind energy resource from mesoscale to microscale model and data assimilating field measurements

    International Nuclear Information System (INIS)

    The main objective of this research work is to develop and evaluate several coupling methods between operational Numerical Weather Prediction (NWP) model and Computational Fluid Dynamics (CFD) model and data assimilate the field measurements into the CFD model. To address the problem of high spatial variation of the topography on the domain lateral boundaries between NWP and CFD domain boundaries, 3 methods – translation, extrapolation and Cressman interpolation are used to impose the NWP model data on the CFD domain lateral boundaries. Newtonian relaxation data assimilation technique is used to incorporate the field measurement data into the CFD simulations. These techniques are studied in a complex site located in southern France. Comparison of wind profiles between the CFD simulation, measurements and CFD simulation with data assimilation are discussed. This combination of state-of-the-art techniques in NWP, CFD, and field data assimilation will provide the basis of a more accurate wind resource assessment method

  7. Montelukast inhibits pentylenetetrazol-induced seizures in rats.

    OpenAIRE

    Çevik, Betül; Solmaz, Volkan; Aksoy, Dürdane; Erbaş, Oytun

    2015-01-01

    Background: Montelukast is an antiinflammatory drug with an antioxidant property. In this study, we aimed to reveal whether montelukast has a preventive effect against seizures and post-seizure oxidative stress in pentylenetetrazol (PTZ)-induced seizures in rats. Material and Methods: Of the 48 male Sprague-Dawley rats used in the study, 24 were assigned to EEG recordings (group A) and 24 were assigned to behavioral studies (group B). In group A, the electrodes were implanted on dura over ...

  8. Montelukast reduces seizures in pentylenetetrazol-kindled mice

    OpenAIRE

    Fleck, J.; F.R. Temp; Marafiga, J.R.; A.C. Jesse; Milanesi, L.H.; L.M. Rambo; C.F. Mello

    2016-01-01

    Cysteinyl leukotrienes (CysLTs) have been implicated in seizures and kindling; however, the effect of CysLT receptor antagonists on seizure frequency in kindled animals and changes in CysLT receptor expression after pentylenetetrazol (PTZ)-induced kindling have not been investigated. In this study, we evaluated whether the CysLT1 inverse agonist montelukast, and a classical anticonvulsant, phenobarbital, were able to reduce seizures in PTZ-kindled mice and alter CysLT receptor expression. Mon...

  9. Montelukast Inhibits Pentylenetetrazol-Induced Seizures in Rats

    OpenAIRE

    Cevik, Betul; Solmaz, Volkan; Aksoy, Durdane; Erbas, Oytun

    2015-01-01

    Background Montelukast is an antiinflammatory drug with an antioxidant property. In this study, we aimed to reveal whether montelukast has a preventive effect against seizures and post-seizure oxidative stress in pentylenetetrazol (PTZ)-induced seizures in rats. Material/Methods Of the 48 male Sprague-Dawley rats used in the study, 24 were assigned to EEG recordings (group A) and 24 were assigned to behavioral studies (group B). In group A, the electrodes were implanted on dura over the left ...

  10. Seizure Prediction and Detection via Phase and Amplitude Lock Values

    OpenAIRE

    Mark H Myers; Padmanabha, Akshay; Hossain, Gahangir; de Jongh Curry, Amy L.; Blaha, Charles D.

    2015-01-01

    A robust seizure prediction methodology would enable a “closed-loop” system that would only activate as impending seizure activity is detected. Such a system would eliminate ongoing stimulation to the brain, thereby eliminating such side effects as coughing, hoarseness, voice alteration, and paresthesias (Murphy et al., 1998; Ben-Menachem, 2001), while preserving overall battery life of the system. The seizure prediction and detection algorithm uses Phase/Amplitude Lock Values (PLV/ALV) which...

  11. Seizure Prediction and Detection via Phase and Amplitude Lock Values

    OpenAIRE

    Mark H Myers; Ashay ePadmanabha; Gahangir eHossain; Amy ede Jongh Curry; Blaha, Charles D.

    2016-01-01

    A robust seizure prediction methodology would enable a ‘closed-loop’ system that would only activate as impending seizure activity is detected. Such a system would eliminate ongoing stimulation to the brain, thereby eliminating such side effects as coughing, hoarseness, voice alteration, and paresthesias (Murphy et al., 1998, Ben-Menachem, 2001), while preserving overall battery life of the system. The seizure prediction and detection algorithm uses Phase/Amplitude Lock Values (PLV/ALV) whi...

  12. Semistructured Interview for Seizure Classification: Agreement with Physicians’ Diagnoses

    OpenAIRE

    Ottman, Ruth; Hauser, W. Allen; Stallone, Lillian

    1990-01-01

    A semi-structured interview was developed for classification of seizures in accordance with the 1981 International League Against Epilepsy (ILAE) criteria. The interview was administered over the telephone by trained lay interviewers. Interview-based diagnoses for 50 patients were compared with independent diagnoses by neurologists who also use the ILAE system for seizure classification. Interview diagnoses agreed with those of physicians for broad seizure-type classifications (i.e., partial ...

  13. Noradrenergic mechanism in the regulation of seizures in GEPR.

    Institute of Scientific and Technical Information of China (English)

    Kwang-HoKo; Dong-OokSeo; Jae-RyunRyu; Chan-YoungShin

    2004-01-01

    Genetically epilepsy prone rat (GEPR) is a model of generalized tonic/clonic epilepsy and a useful tool in the understanding of basic mechanisms of human epilepsy. GEPR is susceptible to audiogenic seizure, hyperthermia induced seizure,and has lower threshold for electrical and chemical stimuli. Several strains of GEPR, from GEPR-3 to GEPR-9, are available depending on the degree of the intensity of audiogenic seizure.

  14. Seizure in later life: an ode to the elderly

    OpenAIRE

    Raminderpal Singh Sibia; Amith Kumar S; Honey Sharma

    2014-01-01

    Background: Seizure disorder and epilepsy are one of the common presenting symptoms to an emergency department for geriatric population. Cerebrovascular accident, metabolic derangement, trauma, neurodegenerative diseases, tumor, infections and psychiatric illnesses add up to the frequent etiological spectrum of seizure in elderly. Objective of current study was to describe clinical and etiological spectrum of seizures in later life. Methods: This retrospective study was conducted from medi...

  15. 8 CFR 280.21 - Seizure of aircraft.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Seizure of aircraft. 280.21 Section 280.21... OF FINES § 280.21 Seizure of aircraft. Seizure of an aircraft under the authority of section 239 of the Act and § 280.2 will not be made if such aircraft is damaged to an extent that its value is...

  16. INTERMITTENT CLONAZEPAM IN THE PREVENTION OF RECURRENT FEBRILE SEIZURES

    OpenAIRE

    Touran MAHMOUDIAN; Omid YAGHINI; Shirin BAJOGHLI

    2010-01-01

    ObjectiveTo evaluate the efficacy and common side effects of intermittent clonazepam in febrile  seizures.Materials & MethodsThis study was an experimental trial designed to determine the efficacy of intermittent clonazepam in febrile seizures .Thirty patients with an age range of 6 months to 5 years (60% male, 40% female) were studied. Children with a history of psychomotor delay, abnormal  neurological examination, a history of antiepileptic drug consumption, and afebrile seizures were excl...

  17. Febrile Seizure Related with Adenovirus Gastroenteritis: A Case Report

    OpenAIRE

    Arslan, Müjgan; Ermiştekin, Halime; Güngör, Serdal

    2015-01-01

    Febrile seizure is the most common, age-dependant, benign, and fever-related convulsion of childhood. Its pathogenesis is still not clear. Fever causing febrile seizures is usually associated with viral infections, mostly upper respiratory tract infections, otitis media, tonsillitis, or urinary tract infections. The incidence of febrile convulsions during gastroenteritis is lower and gastroenteritis is thought to exert a protective feature in febril seizures. Although the most common pathogen...

  18. Predictive factors for generalized seizures after deliberate citalopram overdose

    OpenAIRE

    Waring, W Stephen; Gray, Julie A; Graham, Ann

    2008-01-01

    WHAT IS ALREADY KNOWN ABOUT THIS SUBJECTCitalopram is a common means of self-poisoning in young adults.Generalized seizures are a recognised complication after selective serotonin reuptake inhibitor overdose (including citalopram overdose). WHAT THIS STUDY ADDSThe minimum stated citalopram dose associated with seizures in the absence of co-ingested drugs was 400 mg.Co-ingestion of a tricyclic antidepressant or venlafaxine confers a 15-fold increased risk of seizures.

  19. Mortality predictors of epilepsy and epileptic seizures among hospitalized elderly

    OpenAIRE

    Telma M.R. de Assis; Aroldo Bacellar; Gersonita Costa; Nascimento, Osvaldo J.M.

    2015-01-01

    Epilepsy and epileptic seizures are common brain disorders in the elderly and are associated with increased mortality that may be ascribed to the underlying disease or epilepsy-related causes. Objective To describe mortality predictors of epilepsy and epileptic seizures in elderly inpatients.Method Retrospective analysis was performed on hospitalized elderly who had epilepsy or epileptic seizures, from January 2009 to December 2010. One hundred and twenty patients were enrolled.Results The mo...

  20. Camphor poisoning: An unusual cause of seizure in children

    Directory of Open Access Journals (Sweden)

    Chaitali Patra

    2015-01-01

    Full Text Available Camphor is a pleasant-smelling cyclic ketone with propensity to cause neurologic side-effect, especially seizures. We report a case of 1½-year-old child who after inadvertent consumption of camphor, experienced an episode of generalized tonic clonic seizure. This case highlights the importance of enquiring any intake of material (medicinal or otherwise in every patient presenting with seizure and notifying presence of typical smell, if any.

  1. Does Naloxone Prevent Seizure in Tramadol Intoxicated Patients?

    OpenAIRE

    Nastaran Eizadi-Mood; Dilek Ozcan; Ali Mohammad Sabzghabaee; Parisa Mirmoghtadaee; Mahrang Hedaiaty

    2014-01-01

    Background: Tramadol poisoning has increased in recent years. Seizure is one of the side-effects of tramadol toxicity. There is a controversy about possible preventive effect of naloxone in tramadol poisoning induced seizure. Therefore, this study was performed to compare seizure incidence in tramadol poisoning patients who received and did not receive naloxone, as an opioid antagonist. Methods: This study involved prospective data collection followed by retrospective analysis on 104 tram...

  2. Surface acoustic wave probe implant for predicting epileptic seizures

    Science.gov (United States)

    Gopalsami, Nachappa; Kulikov, Stanislav; Osorio, Ivan; Raptis, Apostolos C.

    2012-04-24

    A system and method for predicting and avoiding a seizure in a patient. The system and method includes use of an implanted surface acoustic wave probe and coupled RF antenna to monitor temperature of the patient's brain, critical changes in the temperature characteristic of a precursor to the seizure. The system can activate an implanted cooling unit which can avoid or minimize a seizure in the patient.

  3. A missed orthopaedic injury following a seizure: a case report

    Directory of Open Access Journals (Sweden)

    O'Connor-Read Laurence

    2007-05-01

    Full Text Available Abstract Numerous orthopaedic injuries can follow a seizure and are often diagnosed late. This is the first documented case of a missed bilateral anterior shoulder dislocation following a seizure. The possible reasons for the greater incidence of posterior dislocations are examined and why bilateral anterior dislocations following a seizure are so rare. The article discusses the reasons for the delay and highlights potential pitfalls and learning points for junior emergency department doctors.

  4. Prediction of geomagnetic secular variation using data assimilation techniques

    International Nuclear Information System (INIS)

    Complete text of publication follows. An important part of geopotential research is to develop models of the time-varying geomagnetic field, not only for scientific use but for practical purposes. The IGRF is the most commonly used model of the field; a very important aspect of this model is the secular variation (SV) model, from which predictions of the field are calculated up to 5 years after the initial epoch. This predictive model is currently calculated from observations alone. Here we propose a new approach, assimilating geomagnetic observations to geodynamo models for SV prediction. Assimilation of measurements and numerical models has been widely used in atmospheric and oceanic studies to better estimate the true dynamical states and to predict more accurately the changes of the observables in future. Similar approaches could be very useful for geomagnetic field modeling, in particular prediction of geomagnetic secular variation (SV) on decadal time scales. We have developed a geomagnetic data assimilation system (MoSSTDAS) to combine geomagnetic field model output for the past 7000 years and our numerical core dynamics model to better constrain the (numerical) core state, and to predict geomagnetic field and secular variations up to 20 years. Our forecast is very accurate. For 5-year forecast, the correlation between the field morphologies at the core-mantle boundary is greater than 99.5% over the 20th century, while the correlation between SVs is larger than 95%. To examine the broad applicability, we are modifying the assimilation process to best emulate the standard practice (e.g. IGRF) in the geomagnetic community, and to benchmark our results with those documented and published in the past.

  5. The Race Race: Assimilation in America

    Science.gov (United States)

    Balis, Andrea; Aman, Michael

    2013-01-01

    Can race and assimilation be taught? Interdisciplinary pedagogy provides a methodology, context, and use of nontraditional texts culled from American cultural history such as from, theater and historical texts. This approach and these texts prove useful for an examination of race and assimilation in America. The paper describes a course that while…

  6. The Future of Seizure Prediction and Intervention: Closing the loop

    Science.gov (United States)

    Nagaraj, Vivek; Lee, Steven; Krook-Magnuson, Esther; Soltesz, Ivan; Benquet, Pascal; Irazoqui, Pedro; Netoff, Theoden

    2014-01-01

    The ultimate goal of epilepsy therapies is to provide seizure control for all patients while eliminating side effects. Improved specificity of intervention through on-demand approaches may overcome many of the limitations of current intervention strategies. This article reviews progress in seizure prediction and detection, potential new therapies to provide improved specificity, and devices to achieve these ends. Specifically, we discuss 1) potential signal modalities and algorithms for seizure detection and prediction, 2) closed-loop intervention approaches, and 3) hardware for implementing these algorithms and interventions. Seizure prediction and therapies maximize efficacy while minimizing side-effects through improved specificity may represent the future of epilepsy treatments. PMID:26035672

  7. Validation of an automated seizure detection algorithm for term neonates

    OpenAIRE

    Mathieson, Sean R; Stevenson, Nathan J.; Low, Evonne; Marnane, William P.; Rennie, Janet M.; Temko, Andrey; Lightbody, Gordon; Geraldine B. Boylan

    2016-01-01

    Objective The objective of this study was to validate the performance of a seizure detection algorithm (SDA) developed by our group, on previously unseen, prolonged, unedited EEG recordings from 70 babies from 2 centres. Methods EEGs of 70 babies (35 seizure, 35 non-seizure) were annotated for seizures by experts as the gold standard. The SDA was tested on the EEGs at a range of sensitivity settings. Annotations from the expert and SDA were compared using event and epoch based metrics. The ef...

  8. Treatment Outcome Of Seizures Associated With Intracranial Cavernous Angiomas

    Directory of Open Access Journals (Sweden)

    Nievera Conrad C

    1999-01-01

    Full Text Available Seizures are among the typical presentations of intracranial cavernous angiomas (ICA. Twenty-one patients (age range: 2 to 53 years treated for seizures associated with ICA between 1983 and 1997 were restrospectively studied to evaluate their outcome following medical or surgical intervention. The mean interval between seizure onset and initial presentation at our institution was 7.6 years. Seizures were simple partial in 3 patients, complex partial in 15 and secondarily generalized tonic-clonic in 13. The commonest site of the lesion was the temporal lobe (52%. Multiple angiomas were observed in 5 (24% patients. Seven (32% patients were medically-managed with antiepileptic therapy and 14 (68% underwent either lesionectomy with resection of the epileptogenic zone (9 patients or temporal lobectomy (5 patients. Mean follow-up time was 4 years (range: 3 months to 14 years. Of the medically-managed patients, 3 (43% remained seizure-free whereas 4 (57% continued to have seizures with an average frequency of one per day. Of the surgically-managed patients, 12 (86% became seizure-free and 2 (14% had no more than two seizures per year. Surgery appears to be extremely effective in the management of seizures associated with ICA and should receive a strong and early consideration in patients who fail medical therapy.

  9. Abnormal radionuclide cerebral angiograms and scans due to seizures

    International Nuclear Information System (INIS)

    The effect of recent seizures on the brain scan was determined in a retrospective study of patients who had had seizures. All patients who underwent brain scanning within eight days of seizures and who did not have a specific intracranial lesion were included. The /sup 99m/Tc-pertechnetate cerebral angiogram and/or delayed scan was abnormal in 73 percent of 22 patients. The data suggest that if seizures occur within six days of the brain imaging, the image is likely to be abnormal. (auth)

  10. Maternal immune activation increases seizure susceptibility in juvenile rat offspring.

    Science.gov (United States)

    Yin, Ping; Zhang, Xin-Ting; Li, Jun; Yu, Lin; Wang, Ji-Wen; Lei, Ge-Fei; Sun, Ruo-Peng; Li, Bao-Min

    2015-06-01

    Epidemiological data suggest a relationship between maternal infection and a high incidence of childhood epilepsy in offspring. However, there is little experimental evidence that links maternal infection with later seizure susceptibility in juvenile offspring. Here, we asked whether maternal immune challenge during pregnancy can alter seizure susceptibility and seizure-associated brain damage in adolescence. Pregnant Sprague-Dawley rats were treated with lipopolysaccharide (LPS) or normal saline (NS) on gestational days 15 and 16. At postnatal day 21, seizure susceptibility to kainic acid (KA) was evaluated in male offspring. Four groups were studied, including normal control (NS-NS), prenatal infection (LPS-NS), juvenile seizure (NS-KA), and "two-hit" (LPS-KA) groups. Our results demonstrated that maternal LPS exposure caused long-term reactive astrogliosis and increased seizure susceptibility in juvenile rat offspring. Compared to the juvenile seizure group, animals in the "two-hit" group showed exaggerated astrogliosis, followed by worsened spatial learning ability in adulthood. In addition, prenatal immune challenge alone led to spatial learning impairment in offspring but had no effect on anxiety. These data suggest that prenatal immune challenge causes a long-term increase in juvenile seizure susceptibility and exacerbates seizure-induced brain injury, possibly by priming astroglia. PMID:25982885

  11. Instability detector of a fragile neural network: application to seizure detection in epilepsy.

    Science.gov (United States)

    Ehrens, Daniel; Sritharan, Duluxan; Sarma, Sridevi V

    2014-01-01

    It has recently been proposed that the epileptic cortex is fragile in the sense that seizures manifest through small perturbations in the synaptic connections that render the entire cortical network unstable. Therefore, one method for detecting seizures is to detect when the neuronal network has gone unstable. This is important for implementing a closed-loop therapy to suppress seizures. In this paper, we consider a widely used nonlinear stochastic model of a neuronal network, and assume that spiking dynamics during non-seizure periods correspond to certain synaptic connections that render its fixed point stable. We then apply a minimum energy perturbation theory we recently developed for networks to determine the changes in the most fragile node's synaptic connections that make the same fixed point unstable (our model during seizure). Then a detector is designed as follows. First a 2-state HMM is constructed (stable=state 1 and unstable=state 2) with fixed state transition probabilities, where the output observation is the firing rate of the most fragile node in the network. The output density functions are assumed to be Gaussian with parameters computed using maximum likelihood estimation on data generated from the nonlinear network model in each state. Then, to detect a transition from stable to unstable, spiking activity is simulated in all nodes from the nonlinear model. The detector first measures the firing rate of the fragile node, and computes the derivative of the cumulative likelihood ratio of the observed firing rate from the HMM's output distributions. When the derivative exceeds a certain threshold, a transition to the unstable state is detected. Various thresholds were tested when firing rate was computed by averaging over a different number of windows of different lengths. High performance was achieved and a tradeoff was found between the accuracy of the detector and the detection delay. PMID:25571501

  12. Assimilation de données: les propriétés asymptotiques du filtre de Kalman d'ensemble

    OpenAIRE

    Tran, Vu Duc

    2009-01-01

    This thesis is concerned with the data assimilation methods which combine the dynamical model with the observations. We present the well-known methods: statistical interpolation, variational data assimilation methods and sequential data assimilation methods. We are particularly interested in the Ensemble Kalman Filter (EnKF) which is more and more used in the oceanographic applications. The Ensemble Kalman Filter has been initially proposed as approximation of the Kalman filter in the case of...

  13. Seizure recurrence after a first febrile convulsion.

    Science.gov (United States)

    Laditan, A A

    1994-01-01

    In this study, 140 children aged from 6 months to 6 years who presented with a first febrile convulsion at the King Fahad Hofuf Hospital, Al-Hassa, Saudi Arabia were retrospectively identified. Information about these children was obtained from their medical records covering a follow-up period of 3 years from July 1989 to June 1992. Recurrent febrile convulsions occurred in 60 of them (43%). Relevant risk factors that were observed to be significantly associated with seizure recurrence included an age of less than 18 months (odds ratio [OR] = 3.82; 95% confidence interval [CI] = 9.26, 1.58), an initial febrile convulsion that was complex (OR = 4.41; CI = 9.50, 2.05) and a positive family history of febrile convulsions (OR = 4.12; CI = 10.74; 1.58), while a decreased risk of recurrence occurred with a temperature of over 39 degrees C (OR = 4.60; CI = 9.44; 2.24). There was no association between seizure recurrence and the duration of the initial febrile convulsion (OR = 0.93; CI = 2.33; -2.04) or family history of epilepsy (OR = 0.88; CI = 4.22, -3.27). An important observation in the present study is the close association (ORM-H = 2.36; X2M-H = 9.65) between the development of an afebrile convulsion and seizure recurrence among the group of children with CFC. Anticonvulsant prophylaxis should therefore be considered for children whose initial febrile convulsions are complex in nature. PMID:7880092

  14. Carbamazepine Clearance and Seizure Stability during Pregnancy

    OpenAIRE

    Johnson, Emily L.; Stowe, Zachary N.; Ritchie, James C; Newport, D. Jeffrey; Newman, Melanee L.; Knight, Bettina; Pennell, Page B

    2014-01-01

    The aims of this study were to characterize the alterations in total and free carbamazepine (CBZ) and total and free carbamazepine-epoxide (CBZ-EPO) clearances during pregnancy; to calculate the change in free fractions of CBZ and CBZ-EPO during pregnancy; and to determine whether seizure worsening is associated with a low ratio to non-pregnant baseline concentration of total or free CBZ or CBZ-EPO. Women on CBZ were enrolled before conception or during pregnancy in this prospective, observat...

  15. Lipopolysaccharide potentiates hyperthermia-induced seizures

    OpenAIRE

    Eun, Baik-Lin; Abraham, Jayne; Mlsna, Lauren; Kim, Min Jung; Koh, Sookyong

    2015-01-01

    Background Prolonged febrile seizures (FS) have both acute and long-lasting effects on the developing brain. Because FS are often associated with peripheral infection, we aimed to develop a preclinical model of FS that simulates fever and immune activation in order to facilitate the implementation of targeted therapy after prolonged FS in young children. Methods The innate immune activator lipopolysaccharide (LPS) was administered to postnatal day 14 rat (200 μg/kg) and mouse (100 μg/kg) pups...

  16. Multi-modal Intelligent Seizure Acquisition (MISA) system - A new approach towards seizure detection based on full body motion measures

    DEFF Research Database (Denmark)

    Conradsen, Isa; Beniczky, Sándor; Wolf, Peter; Terney, Daniella; Sams, Thomas; Sørensen, Helge Bjarup Dissing

    hazards. Today no reliable alarm systems are available. A Multi-modal Intelligent Seizure Acquisition (MISA) system based on full body motion data seems as a good approach towards detection of epileptic seizures. The system is the first to provide a full body description for epilepsy applications. Three......) and audio and video recording. The results showed that a non-subject specific MISA system developed on data from the modalities: accelerometer (ACM), gyroscope and EMG is able to detect 98% of the simulated seizures and at the same time mistakes only 4 of the normal movements for seizures. If the...

  17. SERUM CHEMISTRY ABNORMALITIES IN CHILDREN WITH UNPROVOKED SEIZURES

    Directory of Open Access Journals (Sweden)

    J. Akhondian MD

    2009-01-01

    Full Text Available ObjectiveMost children brought to the emergency department (ED for evaluation of seizures undergo an extensive laboratory workup. Since results are usually negative, the value of such routine laboratory workups has been questioned. A group of children with unprovoked seizures was prospectively studied to determine the diagnostic values of routine serum chemistries and to identify risk factors predictive of abnormal findings.Materials & MethodsAll patients evaluated at the ED of the Ghaem hospital during a consecutive 12 months period between Jan 2004 through Jan 2005 were studied. We collected data for patient's demographics, details of the history of present illness (including vomiting, diarrhea, apnea, medication use, past history of seizures, family history of seizures, metabolic disorders or other chronic medical illnesses, neonatal history and neurological examination as well as nutritional status, type and time of seizure. The role of abnormal serum chemistries as a seizure trigger factor was assessed in patients with a history of seizure.ResultsA total of 210 patients (mean age 19.2 months with unprovoked seizures were evaluated. Twenty- three serum abnormalities were noted in the patients (12 cases of hyponatremia, 7 of hypoglycemia, 4 of hypokalemia, 4 of uremia. The incidence of abnormal serum biochemical values was higher in patients with a first seizure, younger patients, and those with gastrointestinal symptoms.ConclusionAccording to the present study, one can conclude that in children younger than 2 years and having no structural CNS abnormality, electrolyte and glucose screening is recommended only for a first unprovoked seizure, when gastrointestinal symptoms or symptoms suggesting electrolyte disturbances are present.Keywords:Unprovoked, Seizure, Biochemistry, Children

  18. An integrative view of mechanisms underlying generalized spike-and-wave epileptic seizures and its implication on optimal therapeutic treatments.

    Directory of Open Access Journals (Sweden)

    Boyuan Yan

    Full Text Available Many types of epileptic seizures are characterized by generalized spike-and-wave discharges. In the past, notable effort has been devoted to understanding seizure dynamics and various hypotheses have been proposed to explain the underlying mechanisms. In this paper, by taking an integrative view of the underlying mechanisms, we demonstrate that epileptic seizures can be generated by many different combinations of synaptic strengths and intrinsic membrane properties. This integrative view has important medical implications: the specific state of a patient characterized by a set of biophysical characteristics ultimately determines the optimal therapeutic treatment. Through the same view, we further demonstrate the potentiation effect of rational polypharmacy in the treatment of epilepsy and provide a new angle to resolve the debate on polypharmacy. Our results underscore the need for personalized medicine and demonstrate that computer modeling and simulation may play an important role in assisting the clinicians in selecting the optimal treatment on an individual basis.

  19. Variational assimilation of Lagrangian data in oceanography

    CERN Document Server

    Nodet, Maëlle

    2008-01-01

    We consider the assimilation of Lagrangian data into a primitive equations circulation model of the ocean at basin scale. The Lagrangian data are positions of floats drifting at fixed depth. We aim at reconstructing the four-dimensional space-time circulation of the ocean. This problem is solved using the four-dimensional variational technique and the adjoint method. In this problem the control vector is chosen as being the initial state of the dynamical system. The observed variables, namely the positions of the floats, are expressed as a function of the control vector via a nonlinear observation operator. This method has been implemented and has the ability to reconstruct the main patterns of the oceanic circulation. Moreover it is very robust with respect to increase of time-sampling period of observations. We have run many twin experiments in order to analyze the sensitivity of our method to the number of floats, the time-sampling period and the vertical drift level. We compare also the performances of th...

  20. A New Approach to Data Assimilation

    Institute of Scientific and Technical Information of China (English)

    Wang Bin; ZHAO Ying

    2006-01-01

    A significant attempt to design a timesaving and efficient four-dimensional variational data assimilation dimensional variational data assimilation of mapped observation (3DVM)' is proposed, based on the new concept of mapped observation and the new idea of backward 4DVar. Like the available 4DVar, 3DVM produces an optimal initial condition (IC) that is consistent with the prediction model due to the inclusion of model constraints and best fits the observations in the assimilation window through the model solution trajectory. Different from the 4DVar, the IC derived from 3DVM is located at the end of the assimilation window rather than at the beginning conventionally. This change greatly reduces the computing cost for the new approach, which is almost the same as that of the three-dimensional variational data assimilation (3DVar). Especially, such a change is able to improve assimilation accuracy because it does not need the tangential linear and adjoint approximations to calculate the gradient of cost function. Therefore,in numerical test, the new approach produces better IC than 4DVar does for 72-h simulation of TY9914(Dan), by assimilating the three-dimensional fields of temperature and wind retrieved from the Advanced Microwave Sounding Unit-A (AMSU-A) observations. Meanwhile, it takes only 1/7 of the computing cost that the 4DVar requires for the same initialization with the same retrieved data.

  1. Skill Assessment in Ocean Biological Data Assimilation

    Science.gov (United States)

    Gregg, Watson W.; Friedrichs, Marjorie A. M.; Robinson, Allan R.; Rose, Kenneth A.; Schlitzer, Reiner; Thompson, Keith R.; Doney, Scott C.

    2008-01-01

    There is growing recognition that rigorous skill assessment is required to understand the ability of ocean biological models to represent ocean processes and distributions. Statistical analysis of model results with observations represents the most quantitative form of skill assessment, and this principle serves as well for data assimilation models. However, skill assessment for data assimilation requires special consideration. This is because there are three sets of information in the free-run model, data, and the assimilation model, which uses Data assimilation information from both the flee-run model and the data. Intercom parison of results among the three sets of information is important and useful for assessment, but is not conclusive since the three information sets are intertwined. An independent data set is necessary for an objective determination. Other useful measures of ocean biological data assimilation assessment include responses of unassimilated variables to the data assimilation, performance outside the prescribed region/time of interest, forecasting, and trend analysis. Examples of each approach from the literature are provided. A comprehensive list of ocean biological data assimilation and their applications of skill assessment, in both ecosystem/biogeochemical and fisheries efforts, is summarized.

  2. Congenital hypothyroidism with seizures: a case report

    Directory of Open Access Journals (Sweden)

    Ann Vivian Sproul

    2016-03-01

    Full Text Available Congenital hypothyroidism (CH is defined as thyroid hormone deficiency, present at birth. It is seen in 1:4,000 births and is caused by an anatomical defect, known as thyroid dysgenesis (underdevelopment or unusual location of the thyroid gland, by abnormal biosynthesis of the thyroid hormones (dyshormogenesis, inborn errors of metabolism, genetic mutations or iodine deficiency. If untreated, severe neurological impairment develops. However, newborn screening programs have improved outcomes greatly, through early diagnosis and treatment. Clinical manifestations are often subtle at birth, due to the placental transfer of thyroxine (T4, thus making diagnosis in the first few days of life difficult. Increased levels of thyroid stimulating hormone (TSH and low levels of T4 are confirmatory for this disorder. We describe the case of a baby with CH who presented with neonatal seizures: a rare clinical presentation. Our case highlights the need to eliminate CH, as a cause of seizures, so that treatment can be initiated even more promptly to optimize neurological sequelae and outcome.

  3. All together now: Analogies between chimera state collapses and epileptic seizures

    Science.gov (United States)

    Andrzejak, Ralph G.; Rummel, Christian; Mormann, Florian; Schindler, Kaspar

    2016-03-01

    Conceptually and structurally simple mathematical models of coupled oscillator networks can show a rich variety of complex dynamics, providing fundamental insights into many real-world phenomena. A recent and not yet fully understood example is the collapse of coexisting synchronous and asynchronous oscillations into a globally synchronous motion found in networks of identical oscillators. Here we show that this sudden collapse is promoted by a further decrease of synchronization, rather than by critically high synchronization. This strikingly counterintuitive mechanism can be found also in nature, as we demonstrate on epileptic seizures in humans. Analyzing spatiotemporal correlation profiles derived from intracranial electroencephalographic recordings (EEG) of seizures in epilepsy patients, we found a pronounced decrease of correlation at the seizure onsets. Applying our findings in a closed-loop control scheme to models of coupled oscillators in chimera states, we succeed in both provoking and preventing outbreaks of global synchronization. Our findings not only advance the understanding of networks of coupled dynamics but can open new ways to control them, thus offering a vast range of potential new applications.

  4. Application of data assimilation methods for analysis and integration of observed and modeled Arctic Sea ice motions

    Science.gov (United States)

    Meier, Walter Neil

    This thesis demonstrates the applicability of data assimilation methods to improve observed and modeled ice motion fields and to demonstrate the effects of assimilated motion on Arctic processes important to the global climate and of practical concern to human activities. Ice motions derived from 85 GHz and 37 GHz SSM/I imagery and estimated from two-dimensional dynamic-thermodynamic sea ice models are compared to buoy observations. Mean error, error standard deviation, and correlation with buoys are computed for the model domain. SSM/I motions generally have a lower bias, but higher error standard deviations and lower correlation with buoys than model motions. There are notable variations in the statistics depending on the region of the Arctic, season, and ice characteristics. Assimilation methods are investigated and blending and optimal interpolation strategies are implemented. Blending assimilation improves error statistics slightly, but the effect of the assimilation is reduced due to noise in the SSM/I motions and is thus not an effective method to improve ice motion estimates. However, optimal interpolation assimilation reduces motion errors by 25--30% over modeled motions and 40--45% over SSM/I motions. Optimal interpolation assimilation is beneficial in all regions, seasons and ice conditions, and is particularly effective in regimes where modeled and SSM/I errors are high. Assimilation alters annual average motion fields. Modeled ice products of ice thickness, ice divergence, Fram Strait ice volume export, transport across the Arctic and interannual basin averages are also influenced by assimilated motions. Assimilation improves estimates of pollutant transport and corrects synoptic-scale errors in the motion fields caused by incorrect forcings or errors in model physics. The portability of the optimal interpolation assimilation method is demonstrated by implementing the strategy in an ice thickness distribution (ITD) model. This research presents an

  5. Using trend templates in a neonatal seizure algorithm improves detection of short seizures in a foetal ovine model

    International Nuclear Information System (INIS)

    Seizures below one minute in duration are difficult to assess correctly using seizure detection algorithms. We aimed to improve neonatal detection algorithm performance for short seizures through the use of trend templates for seizure onset and end. Bipolar EEG were recorded within a transiently asphyxiated ovine model at 0.7 gestational age, a common experimental model for studying brain development in humans of 30–34 weeks of gestation. Transient asphyxia led to electrographic seizures within 6–8 h. A total of 3159 seizures, 2386 shorter than one minute, were annotated in 1976 h-long EEG recordings from 17 foetal lambs. To capture EEG characteristics, five features, sensitive to seizures, were calculated and used to derive trend information. Feature values and trend information were used as input for support vector machine classification and subsequently post-processed. Performance metrics, calculated after post-processing, were compared between analyses with and without employing trend information. Detector performance was assessed after five-fold cross-validation conducted ten times with random splits. The use of trend templates for seizure onset and end in a neonatal seizure detection algorithm significantly improves the correct detection of short seizures using two-channel EEG recordings from 54.3% (52.6–56.1) to 59.5% (58.5–59.9) at FDR 2.0 (median (range); p < 0.001, Wilcoxon signed rank test). Using trend templates might therefore aid in detection of short seizures by EEG monitoring at the NICU. (paper)

  6. Effect of berberine on pentylenetetrazol-induced seizures in rats

    Directory of Open Access Journals (Sweden)

    Hamid Reza Sadeghnia

    2011-09-01

    Results: Intraperitoneal administration of lower doses of berberine (100 and 200 mg/kg had no significant effects on minimal clonic seizures (MCS and generalized tonic-clonic seizures (GTCS latencies, while injection of 400 mg/kg caused significant increase in both MCS and GTCS latencies (p

  7. Seizure Onset Detection based on one sEMG channel

    DEFF Research Database (Denmark)

    Conradsen, Isa; Beniczky, Sandor; Hoppe, Karsten; Wolf, Peter; Sams, Thomas; Sørensen, Helge Bjarup Dissing

    We present a new method to detect seizure onsets of tonic-clonic epileptic seizures based on surface electromyography (sEMG) data. The proposed method is generic and based on a single channel making it ideal for a small detection or monitoring device. The sEMG signal is high-pass filtered with a...

  8. Seizure Prediction and Detection via Phase and Amplitude Lock Values.

    Science.gov (United States)

    Myers, Mark H; Padmanabha, Akshay; Hossain, Gahangir; de Jongh Curry, Amy L; Blaha, Charles D

    2016-01-01

    A robust seizure prediction methodology would enable a "closed-loop" system that would only activate as impending seizure activity is detected. Such a system would eliminate ongoing stimulation to the brain, thereby eliminating such side effects as coughing, hoarseness, voice alteration, and paresthesias (Murphy et al., 1998; Ben-Menachem, 2001), while preserving overall battery life of the system. The seizure prediction and detection algorithm uses Phase/Amplitude Lock Values (PLV/ALV) which calculate the difference of phase and amplitude between electroencephalogram (EEG) electrodes local and remote to the epileptic event. PLV is used as the seizure prediction marker and signifies the emergence of abnormal neuronal activations through local neuron populations. PLV/ALVs are used as seizure detection markers to demarcate the seizure event, or when the local seizure event has propagated throughout the brain turning into a grand-mal event. We verify the performance of this methodology against the "CHB-MIT Scalp EEG Database" which features seizure attributes for testing. Through this testing, we can demonstrate a high degree of sensivity and precision of our methodology between pre-ictal and ictal events. PMID:27014017

  9. Seizure Prediction and Detection via Phase and Amplitude Lock Values

    Directory of Open Access Journals (Sweden)

    Mark H Myers

    2016-03-01

    Full Text Available A robust seizure prediction methodology would enable a ‘closed-loop’ system that would only activate as impending seizure activity is detected. Such a system would eliminate ongoing stimulation to the brain, thereby eliminating such side effects as coughing, hoarseness, voice alteration, and paresthesias (Murphy et al., 1998, Ben-Menachem, 2001, while preserving overall battery life of the system. The seizure prediction and detection algorithm uses Phase/Amplitude Lock Values (PLV/ALV which calculate the difference of phase and amplitude between EEG electrodes local and remote to the epileptic event. PLV is used as the seizure prediction marker and signifies the emergence of abnormal neuronal activations through local neuron populations. PLV/ALVs are used as seizure detection markers to demarcate the seizure event, or when the local seizure event has propagated throughout the brain turning into a grand-mal event. We verify the performance of this methodology against the ‘CHB-MIT Scalp EEG Database’ which features seizure attributes for testing. Through this testing, we can demonstrate a high degree of sensivity and precision of our methodology between pre-ictal and ictal events.

  10. 14 CFR 13.17 - Seizure of aircraft.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Seizure of aircraft. 13.17 Section 13.17... INVESTIGATIVE AND ENFORCEMENT PROCEDURES Legal Enforcement Actions § 13.17 Seizure of aircraft. (a) Under... by the Regional Administrator of the region, or by the Chief Counsel, may summarily seize an...

  11. Detection of Epileptic Seizures with Multi-modal Signal Processing

    DEFF Research Database (Denmark)

    Conradsen, Isa

    The main focus of this dissertation lies within the area of epileptic seizure detection. Medically refractory epileptic patients suffer from the unawareness of when the next seizure sets in, and what the consequences will be. A wearable device based on uni- or multi-modalities able to detect and ...

  12. Detection of early seizures by diffuse optical tomography

    Science.gov (United States)

    Zhang, Tao; Hajihashemi, M. Reza; Zhou, Junli; Carney, Paul R.; Jiang, Huabei

    2015-03-01

    In epilepsy it has been challenging to detect early changes in brain activity that occurs prior to seizure onset and to map their origin and evolution for possible intervention. Besides, preclinical seizure experiments need to be conducted in awake animals with images reconstructed and displayed in real-time. We demonstrate using a rat model of generalized epilepsy that diffuse optical tomography (DOT) provides a unique functional neuroimaging modality for noninvasively and continuously tracking brain activities with high spatiotemporal resolution. We developed methods to conduct seizure experiments in fully awake rats using a subject-specific helmet and a restraining mechanism. For the first time, we detected early hemodynamic responses with heterogeneous patterns several minutes preceding the electroencephalographic seizure onset, supporting the presence of a "pre-seizure" state both in anesthetized and awake rats. Using a novel time-series analysis of scattering images, we show that the analysis of scattered diffuse light is a sensitive and reliable modality for detecting changes in neural activity associated with generalized seizure. We found widespread hemodynamic changes evolving from local regions of the bilateral cortex and thalamus to the entire brain, indicating that the onset of generalized seizures may originate locally rather than diffusely. Together, these findings suggest DOT represents a powerful tool for mapping early seizure onset and propagation pathways.

  13. 27 CFR 478.152 - Seizure and forfeiture.

    Science.gov (United States)

    2010-04-01

    ...) of the Act, where the firearm or ammunition intended to be used in such offense is involved in a... firearm or ammunition is intended to be used in such offense by the transferor of such firearm or... Exemptions, Seizures, and Forfeitures § 478.152 Seizure and forfeiture. (a) Any firearm or...

  14. 19 CFR 162.63 - Arrests and seizures.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Arrests and seizures. 162.63 Section 162.63 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Controlled Substances, Narcotics, and Marihuana §...

  15. Seizures in Fragile X Syndrome: Characteristics and Comorbid Diagnoses

    Science.gov (United States)

    Berry-Kravis, Elizabeth; Raspa, Melissa; Loggin-Hester, Lisa; Bishop, Ellen; Holiday, David; Bailey, Donald B., Jr.

    2010-01-01

    A national survey of caregivers of individuals with fragile X syndrome addressed characteristics of epilepsy and co-occurring conditions. Of the 1,394 individuals (1,090 males and 304 females) with the full mutation, 14% of males and 6% of females reported seizures. Seizures were more often partial, began between ages 4 and 10 years, and were…

  16. Responding to Seizures (A Cup of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2015-11-26

    As traumatic as epilepsy can be for the person experiencing seizures, it can be just as troubling for witnesses who want to try and help. In this podcast, Rosemarie Kobau discusses the appropriate way to help someone who is experiencing a seizure.  Created: 11/26/2015 by MMWR.   Date Released: 11/26/2015.

  17. Responding to Seizures (A Minute of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2015-11-26

    When helping someone with a seizure, it’s important to remain calm. This podcast discusses what to do if you witness someone having a seizure.  Created: 11/26/2015 by MMWR.   Date Released: 11/26/2015.

  18. Temporal epileptic seizures and occupational exposure to solvents

    DEFF Research Database (Denmark)

    Jacobsen, M; Bælum, Jesper; Bonde, J P

    1994-01-01

    Long term exposure to organic solvents is usually not considered as a possible cause of chronic epileptic seizures. A case that shows a remarkable coincidence between exposure to organic solvents and occurrence of epileptic seizures is reported. The man was a 58 year old sign writer with lifelong...

  19. Assimilation of temperature into an isopycnal ocean general circulation model using a parallel ensemble Kalman filter

    Science.gov (United States)

    Keppenne, Christian L.; Rienecker, Michele M.

    2003-04-01

    Temperature data from the Tropical Atmosphere and Ocean (TAO) array are assimilated into the Pacific basin configuration of the Poseidon quasi-isopycnal ocean general circulation model (OGCM) using a multivariate ensemble Kalman filter (EnKF) implemented on a massively parallel computer architecture. An assimilation algorithm whereby each processing element (PE) solves a localized analysis problem is used. The algorithm relies on a locally supported error-covariance model to avoid the introduction of spurious long-range covariances associated with small ensemble sizes and to facilitate its efficient parallel implementation on a computing platform with distributed memory. Each time data are assimilated, multivariate background-error statistics estimated from the phase-space distribution of an ensemble of model states are used to calculate the Kalman gain matrix and the analysis increments. The resulting cross-field covariances are used to compute temperature, salinity and current increments. The layer thicknesses are left unchanged by the analysis. Instead, they are dynamically adjusted by the model between successive analyses. Independent acoustic Doppler current profiler data are used to assess the performance of the temperature data assimilation. The temperature analyses are also compared to analyses obtained with a univariate optimal interpolation (UOI) algorithm and to a control run without temperature assimilation. The results demonstrate that the multivariate EnKF is both practical and effective for assimilating in situ and remotely sensed observations into a high resolution ocean model in a quasi-operational framework.

  20. Assimilation of microwave brightness temperatures for soil moisture estimation using particle filter

    International Nuclear Information System (INIS)

    Soil moisture plays a significant role in global water cycles. Both model simulations and remote sensing observations have their limitations when estimating soil moisture on a large spatial scale. Data assimilation (DA) is a promising tool which can combine model dynamics and remote sensing observations to obtain more precise ground soil moisture distribution. Among various DA methods, the particle filter (PF) can be applied to non-linear and non-Gaussian systems, thus holding great potential for DA. In this study, a data assimilation scheme based on the residual resampling particle filter (RR-PF) was developed to assimilate microwave brightness temperatures into the macro-scale semi-distributed Variance Infiltration Capacity (VIC) Model to estimate surface soil moisture. A radiative transfer model (RTM) was used to link brightness temperatures with surface soil moisture. Finally, the data assimilation scheme was validated by experimental data obtained at Arizona during the Soil Moisture Experiment 2004 (SMEX04). The results show that the estimation accuracy of soil moisture can be improved significantly by RR-PF through assimilating microwave brightness temperatures into VIC model. Both the overall trends and specific values of the assimilation results are more consistent with ground observations compared with model simulation results

  1. Montelukast reduces seizures in pentylenetetrazol-kindled mice.

    Science.gov (United States)

    Fleck, J; Temp, F R; Marafiga, J R; Jesse, A C; Milanesi, L H; Rambo, L M; Mello, C F

    2016-01-01

    Cysteinyl leukotrienes (CysLTs) have been implicated in seizures and kindling; however, the effect of CysLT receptor antagonists on seizure frequency in kindled animals and changes in CysLT receptor expression after pentylenetetrazol (PTZ)-induced kindling have not been investigated. In this study, we evaluated whether the CysLT1 inverse agonist montelukast, and a classical anticonvulsant, phenobarbital, were able to reduce seizures in PTZ-kindled mice and alter CysLT receptor expression. Montelukast (10 mg/kg, sc) and phenobarbital (20 mg/kg, sc) increased the latency to generalized seizures in kindled mice. Montelukast increased CysLT1 immunoreactivity only in non-kindled, PTZ-challenged mice. Interestingly, PTZ challenge decreased CysLT2 immunoreactivity only in kindled mice. CysLT1 antagonists appear to emerge as a promising adjunctive treatment for refractory seizures. Nevertheless, additional studies are necessary to evaluate the clinical implications of this research. PMID:26909785

  2. Seizure in Pregnancy Following Cerebral Venous Sinus Thrombosis

    Science.gov (United States)

    Farzi, Farnoush; Abdollahzadeh, Mehrsima; Faraji, Roya; Chavoushi, Tahereh

    2015-01-01

    Introduction: Seizure involves less than 1% of pregnancies; however it is associated with increased maternal and fetal complications. Cerebral venous sinus thrombosis is a rare, but potentially life-threatening cause of seizure during pregnancy, presenting primarily as seizure in 12% - 31.9% of cases. Pregnancy and puerperium are known as the risk factors of cerebral venous sinus thrombosis. Case Presentation: Here is presented a case of seizure after delivery by cesarean section in an otherwise healthy woman. The final diagnosis was cerebral venous sinus thrombosis probably due to hypercoagulable state in pregnancy. Conclusions: If seizure occurs during the peripartum period, along with providing complete cardiovascular and respiratory support, advanced diagnostic measures are needed and cerebral venous sinus thrombosis should be considered as a possible diagnosis. PMID:26161329

  3. Binge Drinking During Pregnancy and Risk of Seizures in Childhood:

    DEFF Research Database (Denmark)

    Sun, Yuelian; Strandberg-Larsen, Katrine; Vestergaard, Mogens;

    2009-01-01

    Seizures are often found in children with fetal alcohol syndrome, but it is not known whether binge drinking during pregnancy by nonalcoholic women is associated with an increased risk of seizure disorders in children. The authors conducted a population-based cohort study of 80,526 liveborn...... singletons in the Danish National Birth Cohort (1996-2002). Information on maternal binge drinking (intake of >/=5 drinks on a single occasion) was collected in 2 computer-assisted telephone interviews during pregnancy. Children were followed for up to 8 years. Information on neonatal seizures, epilepsy, and...... febrile seizures was retrieved from the Danish National Hospital Register. Results showed that exposure to binge drinking episodes during pregnancy was not associated with an increased risk of seizure disorders in children, except for those exposed at 11-16 gestational weeks. These children had a 3...

  4. Surface Temperature Assimilation in the Global Land Data Assimilation System (GLDAS)

    Science.gov (United States)

    Bosilovich, Michael G.; Radakovich, Jon D.; daSilva, Arlindo; Houser, Paul R.; Atlas, Robert M. (Technical Monitor)

    2002-01-01

    The Global Land Data Assimilation System (GLDAS) is a global land parameterization that uses prescribed meteorology as forcing in order to determine regular gridded land surface states (temperature and moisture) and other properties (e.g. water and heat fluxes). In the present experiment, the assimilation of surface skin temperature is incorporated into the land parameterizations. The meteorological forcing was derived from the Goddard Earth Observing System (GEOS-3) Data Assimilation System (DAS) for the full year of 1998 GLDAS can use several land parameterizations, but here we use the Mosaic land surface model and the Common Land Model (CLM). TOVS surface temperature observations are assimilated into GLDAS. The TOVS observations are less frequent that observations used in previous experiments (ISCCP). The purpose of this presentation is to evaluate the impact of the TOVS assimilation on both Mosaic and CLM. We will especially consider the impact of coarse temporal observations on the assimilation and bias correction.

  5. Inter-modality comparisons of seizure focus lateralization in complex partial seizures

    International Nuclear Information System (INIS)

    Anterior temporal lobectomy offers a high chance of seizure-free outcome in patients suffering from drug-refractory complex partial seizure (CPS) originating from the temporal lobe. Other than EEG, several functional and morphologic imaging methods are used to define the spatial seizure origin. The present study was undertaken to compare the merits of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), magnetic resonance imaging (MRI) and single-voxel proton MR spectroscopy (MRS) for the lateralization of temporal lobe seizure foci. The clinical charts and imaging data of 43 consecutive CPS patients were reviewed. Based on surface EEG, 31 patients were classified with temporal lobe epilepsy (TLE; 25 lateralized, 6 not lateralized) and 12 with non-temporal lobe epilepsy. All were examined by FDG-PET, MRS and MRI within 6 weeks. FDG-PET and MRI were interpreted visually, while the N-acetyl-aspartate to creatine ratio was used for MRS interpretation. One FDG-PET scan was invalid due to seizure activity post injection. The MR spectra could not be evaluated in five cases bilaterally and three cases unilaterally for technical reasons. A total of 15 patients underwent anterior temporal lobectomy. All showed a beneficial postoperative outcome. When the proportions of agreement between FDG-PET (0.77), MRI (0.58) and MRS (0.56) and surface EEG in TLE cases were compared, there were no significant differences (P>0.10). However, FDG-PET showed a significantly higher agreement (0.93) than MRI (0.60; P=0.03) with the side of successful temporal lobectomy. The concordance of MRS with the side of successful temporal lobectomy was intermediate (0.75). When the results of functional and morphologic imaging were combined, no significant differences were found between the rates of agreement of FDG-PET/MRI and MRS/MRI with EEG (0.80 vs 0.68; P=0.50) and with the side of successful temporal lobectomy (0.87 vs 0.92; P=0.50) in TLE cases. However, MRS/MRI showed

  6. Inter-modality comparisons of seizure focus lateralization in complex partial seizures

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, P.T.; Cortes-Blanco, A.; Pourdehnad, M.; Desiderio, L.; Jang, S.; Alavi, A. [Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Radiology; Levy-Reis, I. [Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Neurology

    2001-10-01

    Anterior temporal lobectomy offers a high chance of seizure-free outcome in patients suffering from drug-refractory complex partial seizure (CPS) originating from the temporal lobe. Other than EEG, several functional and morphologic imaging methods are used to define the spatial seizure origin. The present study was undertaken to compare the merits of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), magnetic resonance imaging (MRI) and single-voxel proton MR spectroscopy (MRS) for the lateralization of temporal lobe seizure foci. The clinical charts and imaging data of 43 consecutive CPS patients were reviewed. Based on surface EEG, 31 patients were classified with temporal lobe epilepsy (TLE; 25 lateralized, 6 not lateralized) and 12 with non-temporal lobe epilepsy. All were examined by FDG-PET, MRS and MRI within 6 weeks. FDG-PET and MRI were interpreted visually, while the N-acetyl-aspartate to creatine ratio was used for MRS interpretation. One FDG-PET scan was invalid due to seizure activity post injection. The MR spectra could not be evaluated in five cases bilaterally and three cases unilaterally for technical reasons. A total of 15 patients underwent anterior temporal lobectomy. All showed a beneficial postoperative outcome. When the proportions of agreement between FDG-PET (0.77), MRI (0.58) and MRS (0.56) and surface EEG in TLE cases were compared, there were no significant differences (P>0.10). However, FDG-PET showed a significantly higher agreement (0.93) than MRI (0.60; P=0.03) with the side of successful temporal lobectomy. The concordance of MRS with the side of successful temporal lobectomy was intermediate (0.75). When the results of functional and morphologic imaging were combined, no significant differences were found between the rates of agreement of FDG-PET/MRI and MRS/MRI with EEG (0.80 vs 0.68; P=0.50) and with the side of successful temporal lobectomy (0.87 vs 0.92; P=0.50) in TLE cases. However, MRS/MRI showed

  7. DAO's Finite-volume/Physical-space Data Assimilation System: Stratospheric Applications

    Science.gov (United States)

    daSilva, Arlindo; Lin, S.-J.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    In this talk we describe the next-generation data assimilation system being developed at NASA's Data Assimilation Office (DAO), with emphasis on the applications to stratospheric forecasts and stratospheric constituent transport. This data assimilation system includes the General Circulation Model jointly developed by the DAO and the Climate and Global Dynamics Division (CGDD) at NCAR. This model is based on the finite-volume dynamical core) developed at DAO with physical parameterizations from the NCAR Climate Community Model. The Physical-space Statistical Analysis System (PSAS) is used to combine a first guess from the NASA-NCAR GCM with observational data to provide an updated estimate of the state of the atmosphere. Case studies for the (northern) Winter of 2000 will be discussed.

  8. SERUM CHEMISTRY ABNORMALITIES IN CHILDREN WITH UNPROVOKED SEIZURES

    Directory of Open Access Journals (Sweden)

    J. Akhondian MD,

    2007-02-01

    Full Text Available ObjectiveMost children brought to the emergency department (ED for evaluation of seizures undergo an extensive laboratory workup. Since results are usually negative, the value of such routine laboratory workups has been questioned. A group of children with unprovoked seizures was prospectively studied to determine the diagnostic values of routine serum chemistries and to identify risk factors predictive of abnormal findings.Materials & MethodsAll patients evaluated at the ED of the Ghaem hospital during a consecutive 12 months period between Jan 2004 through Jan 2005 were studied. We collected data for patient's demographics, details of the history of present illness (including vomiting, diarrhea, apnea, medication use, past history of seizures, family history of seizures, metabolic disorders or other chronic medical illnesses, neonatal history and neurological examination as well as nutritional status, type and time of seizure. The role of abnormal serum chemistries as a seizure trigger factor was assessed in patients with a history of seizure.ResultsA total of 210 patients (mean age 19.2 months with unprovoked seizures were evaluated. Twenty- three serum abnormalities were noted in the patients (12 cases of hyponatremia, 7 of hypoglycemia, 4 of hypokalemia, 4 of uremia. The incidence of abnormal serum biochemical values was higher in patients with a first seizure, younger patients, and those with gastrointestinal symptoms.ConclusionAccording to the present study, one can conclude that in children younger than 2 years and having no structural CNS abnormality, electrolyte and glucose screening is recommended only for a first unprovoked seizure, when gastrointestinal symptoms or symptoms suggesting electrolyte disturbances are present.

  9. Why Are Seizures Rare in Rapid Eye Movement Sleep? Review of the Frequency of Seizures in Different Sleep Stages

    Directory of Open Access Journals (Sweden)

    Marcus Ng

    2013-01-01

    Full Text Available Since the formal characterization of sleep stages, there have been reports that seizures may preferentially occur in certain phases of sleep. Through ascending cholinergic connections from the brainstem, rapid eye movement (REM sleep is physiologically characterized by low voltage fast activity on the electroencephalogram, REMs, and muscle atonia. Multiple independent studies confirm that, in REM sleep, there is a strikingly low proportion of seizures (~1% or less. We review a total of 42 distinct conventional and intracranial studies in the literature which comprised a net of 1458 patients. Indexed to duration, we found that REM sleep was the most protective stage of sleep against focal seizures, generalized seizures, focal interictal discharges, and two particular epilepsy syndromes. REM sleep had an additional protective effect compared to wakefulness with an average 7.83 times fewer focal seizures, 3.25 times fewer generalized seizures, and 1.11 times fewer focal interictal discharges. In further studies REM sleep has also demonstrated utility in localizing epileptogenic foci with potential translation into postsurgical seizure freedom. Based on emerging connectivity data in sleep, we hypothesize that the influence of REM sleep on seizures is due to a desynchronized EEG pattern which reflects important connectivity differences unique to this sleep stage.

  10. Compensation for complete assimilation in speech perception: The case of Korean labial-to-velar assimilation

    OpenAIRE

    Mitterer, H.; Kim, S.; Cho, T.

    2013-01-01

    In connected speech, phonological assimilation to neighboring words can lead to pronunciation variants (e.g., 'garden bench'→ "gardem bench"). A large body of literature suggests that listeners use the phonetic context to reconstruct the intended word for assimilation types that often lead to incomplete assimilations (e.g., a pronunciation of "garden" that carries cues for both a labial [m] and an alveolar [n]). In the current paper, we show that a similar context effect is observed for an as...

  11. Scalable sequential data assimilation with the Parallel Data Assimilation Framework PDAF

    OpenAIRE

    Nerger, Lars; Hiller, Wolfgang; Schröter, Jens

    2011-01-01

    Data assimilation applications with high-dimensional numerical models exhibit extreme requirements on computational resources. Good scalability of the assimilation system is necessary to make these applications feasible. Sequential data assimilation methods based on ensemble forecasts, like ensemble-based Kalman filters, provide such good scalability, because the forecast of each ensemble member can be performed independently. However, this parallelism has to be combined with the paralleli...

  12. IS ASSIMILATION THEORY DEAD? THE EFFECT OF ASSIMILATION ON ADOLESCENT WELL-BEING

    OpenAIRE

    Greenman, Emily; Xie, Yu

    2008-01-01

    The relationship between assimilation and the well-being of immigrant children has been the focus of debate in the recent sociological literature. Much of this work has questioned whether classical theories of immigrant adaptation, which assumed assimilation to be an integral part of the process of upward mobility for immigrants, are still applicable to today’s immigrant children. This study reevaluates the applicability of classical assimilation theory with a comprehensive empirical assessme...

  13. Extending NEMO for ensemble data assimilation on supercomputers with the parallel data assimilation framework PDAF

    OpenAIRE

    Nerger, Lars; Kirchgessner, Paul

    2014-01-01

    The NEMO model is a state-of-the-art ocean circulation model. For data assimilation applications with ensemble Kalman filters like the SEEK filter, e.g. for operational ocean forecasting, NEMO is typically run separately from the assimilation algorithm. Thus, NEMO is used to generate a set of restart files on disks that hold the ensemble of model forecasts providing the error covariance matrix information for the ensemble Kalman filter. These files need to be read by a separate assimilation p...

  14. THE SOCIAL CONTEXT OF ASSIMILATION: TESTING IMPLICATIONS OF SEGMENTED ASSIMILATION THEORY*

    OpenAIRE

    Xie, Yu; Greenman, Emily

    2011-01-01

    Segmented assimilation theory has been a popular explanation for the diverse experiences of assimilation among new waves of immigrants and their children. While the theory has been interpreted in many different ways, we emphasize its implications for the important role of social context: both processes and consequences of assimilation should depend on the local social context in which immigrants are embedded. We derive empirically falsifiable hypotheses about the interaction effects between s...

  15. Assimilative and non-assimilative color spreading in the watercolor configuration.

    Science.gov (United States)

    Kimura, Eiji; Kuroki, Mikako

    2014-01-01

    A colored line flanking a darker contour will appear to spread its color onto an area enclosed by the line (watercolor effect). The watercolor effect has been characterized as an assimilative effect, but non-assimilative color spreading has also been demonstrated in the same spatial configuration; e.g., when a black inner contour (IC) is paired with a blue outer contour (OC), yellow color spreading can be observed. To elucidate visual mechanisms underlying these different color spreading effects, this study investigated the effects of luminance ratio between the double contours on the induced color by systematically manipulating the IC and the OC luminance (Experiment 1) as well as the background luminance (Experiment 2). The results showed that the luminance conditions suitable for assimilative and non-assimilative color spreading were nearly opposite. When the Weber contrast of the IC to the background luminance (IC contrast) was smaller in size than that of the OC (OC contrast), the induced color became similar to the IC color (assimilative spreading). In contrast, when the OC contrast was smaller than or equal to the IC contrast, the induced color became yellow (non-assimilative spreading). Extending these findings, Experiment 3 showed that bilateral color spreading, i.e., assimilative spreading on one side and non-assimilative spreading on the other side, can also be observed in the watercolor configuration. These results suggest that the assimilative and the non-assimilative spreading were mediated by different visual mechanisms. The properties of the assimilative spreading are consistent with the model proposed to account for neon color spreading (Grossberg and Mingolla, 1985) and extended for the watercolor effect (Pinna and Grossberg, 2005). However, the present results suggest that additional mechanisms are needed to account for the non-assimilative color spreading. PMID:25285074

  16. Assimilative and non-assimilative color spreading in the watercolor configuration

    Directory of Open Access Journals (Sweden)

    Eiji eKimura

    2014-09-01

    Full Text Available A colored line flanking a darker contour will appear to spread its color onto an area enclosed by the line (watercolor effect. The watercolor effect has been characterized as an assimilative effect, but non-assimilative color spreading has also been demonstrated in the same spatial configuration; e.g., when a black inner contour (IC is paired with a blue outer contour (OC, yellow color spreading can be observed. To elucidate visual mechanisms underlying these different color spreading effects, this study investigated the effects of luminance ratio between the double contours on the induced color by systematically manipulating the IC and OC luminances (Experiment 1 as well as the background luminance (Experiment 2. The results showed that the luminance conditions suitable for assimilative and non-assimilative color spreading were nearly opposite. When the Weber contrast of the IC to the background luminances (IC contrast was smaller than that of the OC (OC contrast, the induced color became similar to the IC color (assimilative spreading. In contrast, when the OC contrast was smaller than or equal to the IC contrast, the induced color became yellow (non-assimilative spreading. Extending these findings, Experiment 3 showed that bilateral color spreading, e.g., assimilative spreading on one side and non-assimilative spreading on the other side, can also be observed in the watercolor configuration. These results suggest that the assimilative and non-assimilative spreading were mediated by different visual mechanisms. The properties of the assimilative spreading are consistent with the model proposed to account for neon color spreading [Grossberg, S. & Mingolla, E. (1985 Percept. Psychophys., 38, 141-171] and extended for the watercolor effect [Pinna, B., & Grossberg, S. (2005 J. Opt. Soc. Am. A, 22, 2207-2221]. However, the present results suggest that additional mechanisms are needed to account for the non-assimilative color spreading.

  17. Data assimilation techniques in modeling ocean processes

    Digital Repository Service at National Institute of Oceanography (India)

    Mahadevan, R.; Fernandes, A.A.; Naqvi, S.W.A.

    Three main classes of procedures in data analysis and assimilation viz. Objective Analysis, Optimal Interpolation and variational method, used to process the observed data on atmospheric and ocean parameters are briefly reviewed. The variational...

  18. ERP ASSIMILATION: AN END-USER APPROACH

    Directory of Open Access Journals (Sweden)

    Hurbean Luminita

    2013-07-01

    The paper discusses the ERP adoption based on the IT assimilation theory. The ERP lifecycle is associated with the IT assimilation steps. We propose a distribution of these steps along the lifecycle. Derived from the findings in the reviewed literature we will focus the cultural factors, in particular those related to the end-users (determined as a major impact factor in our previous study: Negovan et al., 2011. Our empirical study is centred on the end-users perspective and it tries to determine if and how their behaviour affects the achievement of the ERP assimilation steps. The paper reasons that organizations that understand the IT assimilation steps correlated to the ERP implementation critical factors are more likely to implement and use ERP successfully.

  19. Assimilation of ammonia in Paracoccus denitrificans.

    Science.gov (United States)

    Mikes, V; Chválová, H; Mátlová, L

    1991-01-01

    Two pathways serve for assimilation of ammonia in Paracoccus denitrificans. Glutamate dehydrogenase (NADP+) catalyzes the assimilation at a high NH4+ concentration. If nitrate serves as the nitrogen source, glutamate is synthesized by glutamate-ammonia ligase and glutamate synthase (NADPH). At a very low NH4+ concentration, all three enzymes are synthesized simultaneously. No direct relationship exists between glutamate dehydrogenase (NADP+) and glutamate-ammonia ligase in P. denitrificans, while the glutamate synthase (NADPH) activity changes in parallel with that of the latter enzyme. Ammonia does not influence the induction or repression of glutamate dehydrogenase (NADP+). The inner concentration of metabolites indicates a possible repression of glutamate dehydrogenase (NADP+) by the high concentration of glutamine or its metabolic products as in the case when NH4+ is formed by assimilative nitrate reduction. No direct effect of the intermediates of nitrate assimilation on the synthesis of glutamate dehydrogenase (NADP+) was observed. PMID:1688163

  20. Management of potential transuranium assimilation cases

    International Nuclear Information System (INIS)

    This review deals primarily with the duties of Health Protection personnel assigned to Savannah River's operatig facilities - as opposed to the role of bioassay and dosimetry specialists - in handling potential transuranium assimilation cases

  1. Data assimilation for air quality models

    DEFF Research Database (Denmark)

    Silver, Jeremy David

    2014-01-01

    higher uncertainties. It is possible, however, to combine information from measurements and models to more accurately estimate the state of the atmosphere using a statistically consistent framework known as “data assimilation”. In this study, three data assimilation schemes are implemented and evaluated....... The data assimilation schemes are coupled to the Danish Eulerian Hemispheric Model (DEHM), a large-scale three-dimensional off-line CTM, and the data ingested were retrievals of atmospheric composition from polar-orbiting satellites. The three assimilation techniques applied were: a three......-dimensional optimal interpolation procedure (OI), an Ensemble Kalman Filter (EnKF), and a three-dimensional variational scheme (3D-var). The three assimilation procedures are described and tested. A multi-faceted approach is taken for the verification, using independent measurements from surface air...

  2. ITERATIVE ALGORITHMS FOR DATA ASSIMILATION PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Iterative algorithms for solving the data assimilation problems are considered, based on the main and adjoint equations. Spectral properties of the control operators of the problem are studied, the iterative algorithms are justified.

  3. Development of a data assimilation algorithm

    DEFF Research Database (Denmark)

    Thomsen, Per Grove; Zlatev, Zahari

    2008-01-01

    efficiently observations in a large-scale model (for example, in order to obtain more reliable initial values). Variational data assimilation techniques are based on a combination of three very important components • numerical methods for solving differential equations, • splitting procedures and......It is important to incorporate all available observations when large-scale mathematical models arising in different fields of science and engineering are used to study various physical and chemical processes. Variational data assimilation techniques can be used in the attempts to utilize...... assimilation technique is applied. Therefore, it is important to study the interplay between the three components of the variational data assimilation techniques as well as to apply powerful parallel computers in the computations. Some results obtained in the search for a good combination of numerical methods...

  4. Psychogenic nonepileptic seizures in children: a review.

    Science.gov (United States)

    Reilly, Colin; Menlove, Leanne; Fenton, Virginia; Das, Krishna B

    2013-10-01

    One of the considerations when a child presents with paroxysmal events is psychogenic nonepileptic seizures (PNES). PNES are discernible changes in behavior or consciousness that resemble epileptic seizures but are not accompanied by electrophysiologic changes. They are usually understood as the manifestation of a conversion disorder that reflects underlying psychological distress. There is a lack of population-based data on the prevalence or incidence of PNES in pediatric populations. The prevalence of PNES in children would appear to be lower than that in the adult population, but the prevalence of PNES seems to increase with age, and nonepileptic paroxysmal events are more likely to be PNES in adolescence than earlier in childhood. In terms of manifestation, PNES in childhood have been described using various categorizations and terminology, making comparisons across studies difficult. There is some evidence that events are more likely to involve unresponsiveness in younger children and prominent motor symptoms in older children. The most common precipitating factors would appear to be school-related difficulties and interpersonal conflict within the child's family. In terms of psychopathology, children with PNES are at high risk for symptoms of depression and anxiety. Accurate diagnosis of PNES in children is likely to involve taking a comprehensive description of the episodes, garnering the child's medical/developmental history, video-electroencephalography (video-EEG) to rule out epileptic seizures, and an evaluation of family functioning. The importance of effective and sensitive communication of the diagnosis of PNES has been emphasized and management approaches will typically involve multidisciplinary efforts to safely manage the events at home and at school. Interventions to reduce the effect of precipitating psychosocial stressors and the involvement of a mental health professional to treat comorbid psychopathology will also form part of an effective

  5. Synchronicity in predictive modelling: a new view of data assimilation

    Science.gov (United States)

    Duane, G. S.; Tribbia, J. J.; Weiss, J. B.

    2006-11-01

    The problem of data assimilation can be viewed as one of synchronizing two dynamical systems, one representing "truth" and the other representing "model", with a unidirectional flow of information between the two. Synchronization of truth and model defines a general view of data assimilation, as machine perception, that is reminiscent of the Jung-Pauli notion of synchronicity between matter and mind. The dynamical systems paradigm of the synchronization of a pair of loosely coupled chaotic systems is expected to be useful because quasi-2D geophysical fluid models have been shown to synchronize when only medium-scale modes are coupled. The synchronization approach is equivalent to standard approaches based on least-squares optimization, including Kalman filtering, except in highly non-linear regions of state space where observational noise links regimes with qualitatively different dynamics. The synchronization approach is used to calculate covariance inflation factors from parameters describing the bimodality of a one-dimensional system. The factors agree in overall magnitude with those used in operational practice on an ad hoc basis. The calculation is robust against the introduction of stochastic model error arising from unresolved scales.

  6. Synchronicity in predictive modelling: a new view of data assimilation

    Directory of Open Access Journals (Sweden)

    G. S. Duane

    2006-01-01

    Full Text Available The problem of data assimilation can be viewed as one of synchronizing two dynamical systems, one representing "truth" and the other representing "model", with a unidirectional flow of information between the two. Synchronization of truth and model defines a general view of data assimilation, as machine perception, that is reminiscent of the Jung-Pauli notion of synchronicity between matter and mind. The dynamical systems paradigm of the synchronization of a pair of loosely coupled chaotic systems is expected to be useful because quasi-2D geophysical fluid models have been shown to synchronize when only medium-scale modes are coupled. The synchronization approach is equivalent to standard approaches based on least-squares optimization, including Kalman filtering, except in highly non-linear regions of state space where observational noise links regimes with qualitatively different dynamics. The synchronization approach is used to calculate covariance inflation factors from parameters describing the bimodality of a one-dimensional system. The factors agree in overall magnitude with those used in operational practice on an ad hoc basis. The calculation is robust against the introduction of stochastic model error arising from unresolved scales.

  7. Conditioning of the Weak-Constraint 4D-Variational Data Assimilation Problem

    Science.gov (United States)

    Nichols, Nancy; El-Said, Adam; Lawless, Amos

    2014-05-01

    Four-dimensional data assimilation (4DVar) has become a standard method in use by major operational weather forecasting centres. The aim of the method is to determine the most likely state of a dynamical system given observations of the system. Under certain statistical assumptions, the maximum a posteriori likelihood Bayesian estimate is obtained as the solution to a weighted nonlinear least squares problem subject to the model equations as strong constraints. The model equations do not provide a perfect representation of the real dynamical system, however, and methods to allow for 'model errors' in the assimilation are a goal of current research. The aim is now to find an optimal estimate of the states over the assimilation window, given the error statistics in the background, observations and model. Various formulations of the weak-constraint objective function can be derived, which possess different characteristics and properties. Here we consider two formulations: one aims to estimate all of the states at each time in the assimilation window; the alternative aims to estimate the initial state and simultaneously the 'model error adjustments' over the assimilation window. We gain insight into the well-posedness of the two formulations, and also the speed of the iteration methods used to solve them, by studying the conditioning of the first order Hessian of the objective function. For our two different formulations of the problem, we derive the structure of the Hessians and establish theoretical bounds on their condition numbers. The behaviour of the conditioning as a function of correlation length-scales, variances and observation configurations is investigated. We show how the conditioning depends on the number of assimilation time steps within a window and hence demonstrate how the different systems behave over longer assimilation windows. We present numerical results to illustrate the behaviour of the two formulations of the problem using simplified models.

  8. A wildland fire model with data assimilation

    OpenAIRE

    Mandel, Jan; Bennethum, Lynn S.; Beezley, Jonathan D.; Coen, Janice L.; Douglas, Craig C.; Kim, Minjeong; Vodacek, Anthony

    2007-01-01

    A wildfire model is formulated based on balance equations for energy and fuel, where the fuel loss due to combustion corresponds to the fuel reaction rate. The resulting coupled partial differential equations have coefficients that can be approximated from prior measurements of wildfires. An ensemble Kalman filter technique with regularization is then used to assimilate temperatures measured at selected points into running wildfire simulations. The assimilation technique is able to modify the...

  9. CHOLESTEROL ASSIMILATION BY COMMERCIAL YOGHURT STARTER CULTURES

    OpenAIRE

    Małgorzata Ziarno; Ewa Sękul; Alvaro Aguado Lafraya

    2007-01-01

    The ability to in vitro cholesterol level reduction in laboratory media has been shown for numerous strains of lactic acid bacteria, but not for all strains of lactic bacteria used in the dairy industry. The aim of this work was the determination of the ability of selected thermophilic lactic acid bacteria to cholesterol assimilation during 24 h culture in MRS broth. Commercial starter cultures showed various ability to cholesterol assimilation from laboratory medium. In case of starter cultu...

  10. Migration, Friendship Ties, and Cultural Assimilation

    OpenAIRE

    Facchini, Giovanni; Patacchini, Eleonora; Steinhardt, Max

    2014-01-01

    In this paper we contribute to the analysis of the assimilation process of migrants by analyzing the extent to which friendship with natives can be seen as a measure of cultural assimilation and investigating the formation of social ties in the host country. Using novel information from the German Socio-Economic Panel, we find that migrants with a German friend are more similar to natives than those without a local companion along several important dimensions, including concerns about the eco...

  11. Effective assimilation of global precipitation: simulation experiments

    OpenAIRE

    Lien, Guo-Yuan; Kalnay, Eugenia; Miyoshi, Takemasa

    2013-01-01

    Past attempts to assimilate precipitation by nudging or variational methods have succeeded in forcing the model precipitation to be close to the observed values. However, the model forecasts tend to lose their additional skill after a few forecast hours. In this study, a local ensemble transform Kalman filter (LETKF) is used to effectively assimilate precipitation by allowing ensemble members with better precipitation to receive higher weights in the analysis. In addition, two other changes i...

  12. On errors in meteorological data assimilation

    OpenAIRE

    Lindskog, Magnus

    2007-01-01

    Data assimilation in Numerical Weather Prediction (NWP) optimally blends observations with atmospheric model data in order to obtain the best possible initial state for an atmospheric model prediction. Specification of error characteristics is an important part of data assimilation. This thesis is concerned with representation of background error standard deviations, with handling of observations, and with observation error characteristics. The research includes both the study of basic assimi...

  13. Wage and occupational assimilation by skill level

    OpenAIRE

    Alcobendas, Miguel Angel; Rodríguez-Planas, Núria; Vegas, Raquel

    2012-01-01

    While much of the literature on immigrants' assimilation has focused on countries with a large tradition of receiving immigrants and with flexible labor markets, very little is known on how immigrants adjust to other types of host economies. With its severe dual labor market, and an unprecedented immigration boom, Spain presents a quite unique experience to analyze immigrations' assimilation process. Using alternative datasets and methodologies, this paper provides evidence of a differential ...

  14. Computational methods for data evaluation and assimilation

    CERN Document Server

    Cacuci, Dan Gabriel

    2013-01-01

    Data evaluation and data combination require the use of a wide range of probability theory concepts and tools, from deductive statistics mainly concerning frequencies and sample tallies to inductive inference for assimilating non-frequency data and a priori knowledge. Computational Methods for Data Evaluation and Assimilation presents interdisciplinary methods for integrating experimental and computational information. This self-contained book shows how the methods can be applied in many scientific and engineering areas. After presenting the fundamentals underlying the evaluation of experiment

  15. Evidence of New Immigrant Assimilation in Canada

    OpenAIRE

    Mary L. Grant

    1999-01-01

    Previous studies of the labour market experience of male immigrants to Canada have uncovered two disturbing trends: declining entry earnings for successive new immigrant cohorts and low assimilation rates. These findings suggest that many of these cohorts may never assimilate. The 1991 Census provides a first look at the immigrant cohorts arriving in the 1980s. These immigrants appear to avoid the plight of their predecessors; entry earnings have stopped falling, and those immigrants arriving...

  16. Employment Assimilation of Immigrants in the Netherlands

    OpenAIRE

    Zorlu, Aslan; Hartog, Joop

    2008-01-01

    This discussion Paper led to a publication in International Journal of Population Research , Vol. 2012, article ID 634276. Using two Dutch labour force surveys, employment assimilation of immigrants is examined. We observe marked differences between immigrants by source country. Non-western immigrants never reach parity with native Dutch. Even second generation immigrants never fully catch up. Caribbean immigrants, who share a colonial history with the Dutch, assimilate relatively quick compa...

  17. Immigrants on Welfare: Assimilation and Benefit Substitution

    OpenAIRE

    Ekhaugen, Tyra

    2005-01-01

    Non-western immigrants in Norway are shown to rely heavily on welfare transfers for several years after immigration. While refugee immigrants assimilate slightly out of welfare, other non-western immigrants assimilate rapidly into welfare. Re-migration is selective for both non-western and western immigrants, insofar as the probability of re-migration correlates negatively with the probability of receiving welfare. We argue that previous studies may have reached biased estimates of welfare as...

  18. The heterogeneity in immigrants unhealthy assimilation

    OpenAIRE

    Barbieri, Paolo Nicola

    2016-01-01

    Immigrants upon their arrival in the United States are in better health condition with respect to their American counterpart however such advantage erodes over time. In this paper, we study the heterogeneity of such unhealthy behaviours assimilation among different arrival cohorts. We focus our analysis on binge drinking and cigarette consumption as a proxy for unhealthy behaviour assimilation by immigrants. Regarding binge drinking we show that more recent immigrant cohorts arriv...

  19. Interethnic Marriages and Economic Assimilation of Immigrants

    OpenAIRE

    Kantarevic, Jasmin

    2004-01-01

    This paper examines the relationship between interethnic marriages and economic assimilation among immigrants in the United States. Two competing hypotheses are evaluated: the productivity hypothesis, according to which immigrants married to native-born spouses assimilate faster than comparable immigrants married to foreign-born spouses because spouses play an integral role in the human capital accumulation of their partners; and the selection hypothesis, according to which the relationship b...

  20. The Acceleration of Immigrant Unhealthy Assimilation

    OpenAIRE

    Giuntella, Osea; Stella, Luca

    2016-01-01

    It is well-known that immigrants tend to be healthier than US natives and that this advantage erodes with time spent in the US. However, we know less about the heterogeneity of these trajectories among arrival cohorts. Recent studies have shown that later arrival cohorts of immigrants have lower entry wages and experience less economic assimilation. In this paper, we investigate whether similar cohort effects can be observed in the weight assimilation of immigrants in the US. Focusing on obes...

  1. Resected Brain Tissue, Seizure Onset Zone and Quantitative EEG Measures: Towards Prediction of Post-Surgical Seizure Control.

    Directory of Open Access Journals (Sweden)

    Christian Rummel

    Full Text Available Epilepsy surgery is a potentially curative treatment option for pharmacoresistent patients. If non-invasive methods alone do not allow to delineate the epileptogenic brain areas the surgical candidates undergo long-term monitoring with intracranial EEG. Visual EEG analysis is then used to identify the seizure onset zone for targeted resection as a standard procedure.Despite of its great potential to assess the epileptogenicty of brain tissue, quantitative EEG analysis has not yet found its way into routine clinical practice. To demonstrate that quantitative EEG may yield clinically highly relevant information we retrospectively investigated how post-operative seizure control is associated with four selected EEG measures evaluated in the resected brain tissue and the seizure onset zone. Importantly, the exact spatial location of the intracranial electrodes was determined by coregistration of pre-operative MRI and post-implantation CT and coregistration with post-resection MRI was used to delineate the extent of tissue resection. Using data-driven thresholding, quantitative EEG results were separated into normally contributing and salient channels.In patients with favorable post-surgical seizure control a significantly larger fraction of salient channels in three of the four quantitative EEG measures was resected than in patients with unfavorable outcome in terms of seizure control (median over the whole peri-ictal recordings. The same statistics revealed no association with post-operative seizure control when EEG channels contributing to the seizure onset zone were studied.We conclude that quantitative EEG measures provide clinically relevant and objective markers of target tissue, which may be used to optimize epilepsy surgery. The finding that differentiation between favorable and unfavorable outcome was better for the fraction of salient values in the resected brain tissue than in the seizure onset zone is consistent with growing evidence that

  2. Data Assimilation: Making Sense of Earth Observation

    Directory of Open Access Journals (Sweden)

    WilliamAlbertLahoz

    2014-05-01

    Full Text Available Climate change, air quality and environmental degradation are important societal challenges for the 21st Century. These challenges require an intelligent response from society, which in turn requires access to information about the Earth System. This information comes from observations and prior knowledge, the latter typically embodied in a model describing relationships between variables of the Earth System. Data assimilation provides an objective methodology to combine observational and model information to provide an estimate of the most likely state and its uncertainty for the whole Earth System. This approach adds value to the observations – by filling in the spatio-temporal gaps in observations; and to the model – by constraining it with the observations. In this review paper we motivate data assimilation as a methodology to fill in the gaps in observational information; illustrate the data assimilation approach with examples that span a broad range of features of the Earth System (atmosphere, including chemistry; ocean; land surface; and discuss the outlook for data assimilation, including the novel application of data assimilation ideas to observational information obtained using Citizen Science. Ultimately, a strong motivation of data assimilation is the many benefits it provides to users. These include: providing the initial state for weather and air quality forecasts; providing analyses and reanalyses for studying the Earth System; evaluating observations, instruments and models; assessing the relative value of elements of the Global Observing System (GOS; and assessing the added value of future additions to the GOS.

  3. Seizure Clustering during Drug Treatment Affects Seizure Outcome and Mortality of Childhood-Onset Epilepsy

    Science.gov (United States)

    Sillanpaa, Matti; Schmidt, Dieter

    2008-01-01

    To provide evidence of whether seizure clustering is associated with drug resistance and increased mortality in childhood-onset epilepsy, a prospective, long-term population-based study was performed. One hundred and twenty patients who had been followed since disease onset (average age 37.0 years, SD 7.1, median 40.0, range 11-42; incident cases)…

  4. POD/DEIM reduced-order strategies for efficient four dimensional variational data assimilation

    International Nuclear Information System (INIS)

    This work studies reduced order modeling (ROM) approaches to speed up the solution of variational data assimilation problems with large scale nonlinear dynamical models. It is shown that a key requirement for a successful reduced order solution is that reduced order Karush–Kuhn–Tucker conditions accurately represent their full order counterparts. In particular, accurate reduced order approximations are needed for the forward and adjoint dynamical models, as well as for the reduced gradient. New strategies to construct reduced order based are developed for proper orthogonal decomposition (POD) ROM data assimilation using both Galerkin and Petrov–Galerkin projections. For the first time POD, tensorial POD, and discrete empirical interpolation method (DEIM) are employed to develop reduced data assimilation systems for a geophysical flow model, namely, the two dimensional shallow water equations. Numerical experiments confirm the theoretical framework for Galerkin projection. In the case of Petrov–Galerkin projection, stabilization strategies must be considered for the reduced order models. The new reduced order shallow water data assimilation system provides analyses similar to those produced by the full resolution data assimilation system in one tenth of the computational time

  5. POD/DEIM reduced-order strategies for efficient four dimensional variational data assimilation

    Energy Technology Data Exchange (ETDEWEB)

    Ştefănescu, R., E-mail: rstefane@vt.edu [Computational Science Laboratory, Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060 (United States); Sandu, A., E-mail: sandu@cs.vt.edu [Computational Science Laboratory, Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060 (United States); Navon, I.M., E-mail: inavon@fsu.edu [The Florida State University, Department of Scientific Computing, Tallahassee, FL 32306 (United States)

    2015-08-15

    This work studies reduced order modeling (ROM) approaches to speed up the solution of variational data assimilation problems with large scale nonlinear dynamical models. It is shown that a key requirement for a successful reduced order solution is that reduced order Karush–Kuhn–Tucker conditions accurately represent their full order counterparts. In particular, accurate reduced order approximations are needed for the forward and adjoint dynamical models, as well as for the reduced gradient. New strategies to construct reduced order based are developed for proper orthogonal decomposition (POD) ROM data assimilation using both Galerkin and Petrov–Galerkin projections. For the first time POD, tensorial POD, and discrete empirical interpolation method (DEIM) are employed to develop reduced data assimilation systems for a geophysical flow model, namely, the two dimensional shallow water equations. Numerical experiments confirm the theoretical framework for Galerkin projection. In the case of Petrov–Galerkin projection, stabilization strategies must be considered for the reduced order models. The new reduced order shallow water data assimilation system provides analyses similar to those produced by the full resolution data assimilation system in one tenth of the computational time.

  6. Body Packing: From Seizures to Laparotomy

    Directory of Open Access Journals (Sweden)

    Joanna M. Janczak

    2015-01-01

    Full Text Available Body packing is a common method for illegal drug trafficking. Complications associated with body packing can be severe and even lead to rapid death. Thus, a timely diagnosis is warranted. As most body packers initially do not show any symptoms, making a correct diagnosis can be rather challenging. We describe a case of a 41-year-old male, who was admitted with an epileptic seizure and who turned out to be a cocaine intoxicated body packer. Due to neurological and cardiovascular deterioration an emergency surgery was performed. Four bags of cocaine could be removed. We discuss the current management regimen in symptomatic and asymptomatic body packers and highlight pearls and pitfalls with diagnosis and treatment.

  7. Body packing: from seizures to laparotomy.

    Science.gov (United States)

    Janczak, Joanna M; Beutner, Ulrich; Hasler, Karin

    2015-01-01

    Body packing is a common method for illegal drug trafficking. Complications associated with body packing can be severe and even lead to rapid death. Thus, a timely diagnosis is warranted. As most body packers initially do not show any symptoms, making a correct diagnosis can be rather challenging. We describe a case of a 41-year-old male, who was admitted with an epileptic seizure and who turned out to be a cocaine intoxicated body packer. Due to neurological and cardiovascular deterioration an emergency surgery was performed. Four bags of cocaine could be removed. We discuss the current management regimen in symptomatic and asymptomatic body packers and highlight pearls and pitfalls with diagnosis and treatment. PMID:25883813

  8. Epileptic Seizure Forewarning by Nonlinear Techniques

    International Nuclear Information System (INIS)

    Nicolet Biomedical Inc. (NBI) is collaborating with Oak Ridge National Laboratory (ORNL) under a Cooperative Research and Development Agreement (CRADA) to convert ORNL's patented technology for forewarning of epileptic seizures to a clinical prototype. This technical report describes the highlights of the first year's effort. The software requirements for the clinical device were specified from which the hardware specifications were obtained. ORNL's research-class FORTRAN was converted to run under a graphical user interface (GUI) that was custom-built for this application by NBI. The resulting software package was cloned to desktop computers that are being tested in five different clinical sites. Two hundred electroencephalogram (EEG) datasets from those clinical sites were provided to ORNL for detailed analysis and improvement of the forewarning methodology. Effort under this CRADA is continuing into the second year as planned

  9. Failure of adaptive self-organized criticality during epileptic seizure attacks.

    Science.gov (United States)

    Meisel, Christian; Storch, Alexander; Hallmeyer-Elgner, Susanne; Bullmore, Ed; Gross, Thilo

    2012-01-01

    Critical dynamics are assumed to be an attractive mode for normal brain functioning as information processing and computational capabilities are found to be optimal in the critical state. Recent experimental observations of neuronal activity patterns following power-law distributions, a hallmark of systems at a critical state, have led to the hypothesis that human brain dynamics could be poised at a phase transition between ordered and disordered activity. A so far unresolved question concerns the medical significance of critical brain activity and how it relates to pathological conditions. Using data from invasive electroencephalogram recordings from humans we show that during epileptic seizure attacks neuronal activity patterns deviate from the normally observed power-law distribution characterizing critical dynamics. The comparison of these observations to results from a computational model exhibiting self-organized criticality (SOC) based on adaptive networks allows further insights into the underlying dynamics. Together these results suggest that brain dynamics deviates from criticality during seizures caused by the failure of adaptive SOC. PMID:22241971

  10. Failure of adaptive self-organized criticality during epileptic seizure attacks.

    Directory of Open Access Journals (Sweden)

    Christian Meisel

    2012-01-01

    Full Text Available Critical dynamics are assumed to be an attractive mode for normal brain functioning as information processing and computational capabilities are found to be optimal in the critical state. Recent experimental observations of neuronal activity patterns following power-law distributions, a hallmark of systems at a critical state, have led to the hypothesis that human brain dynamics could be poised at a phase transition between ordered and disordered activity. A so far unresolved question concerns the medical significance of critical brain activity and how it relates to pathological conditions. Using data from invasive electroencephalogram recordings from humans we show that during epileptic seizure attacks neuronal activity patterns deviate from the normally observed power-law distribution characterizing critical dynamics. The comparison of these observations to results from a computational model exhibiting self-organized criticality (SOC based on adaptive networks allows further insights into the underlying dynamics. Together these results suggest that brain dynamics deviates from criticality during seizures caused by the failure of adaptive SOC.

  11. Assessing Immigrant Assimilation: New Empirical and Theoretical Challenges

    OpenAIRE

    Waters, Mary; Jimenez, Tomas R.

    2005-01-01

    This review examines research on the assimilation of immigrant groups. We review research on four primary benchmarks of assimilation: socioeconomic status, spatial concentration, language assimilation, and intermarriage. The existing literature shows that today's immigrants are largely assimilating into American society along each of these dimensions. This review also considers directions for future research on the assimilation of immigrant groups in new southern and midwestern gateways and h...

  12. Cocaine-Associated Seizures and Incidence of Status Epilepticus

    Directory of Open Access Journals (Sweden)

    Majlesi, Nima DO

    2010-05-01

    Full Text Available Objectives: Acute complications from cocaine abuse are commonly treated in the emergency department (ED; one of the most consequential is status epilepticus. The incidence of this complication is not clearly defined in the prior literature on cocaine-associated sequelae. We evaluated the incidence of status epilepticus in patients with seizures secondary to suspected cocaine use.Methods: We performed a retrospective multi-center study of patients with seizures resulting from cocaine use. We identified study subjects at 15 hospitals by record review and conducted a computer-assisted records search to identify patients with seizures for each institution over a four-year period. We selected subjects from this group on the basis of cocaine use and determined the occurrence of status epilepticus among them. Data were collected on each subject using a standardized data collection form.Results: We evaluated 43 patients in the ED for cocaine-associated seizures. Their age range was 17 to 54, with a mean age was 31 years; 53% were male. Of 43 patients, 42 experienced a single tonic-clonic seizure and one developed status epilepticus. All patients had either a history of cocaine use or positive urine drug screen for cocaine.Conclusion: Despite reported cases of status epilepticus with cocaine-induced seizures, the incidence of this complication was unclear based on prior literature. This study shows that most cocaine-associated seizures are self-limited. [West J Emerg Med. 2010; 11(2:157-160.

  13. INTERMITTENT CLONAZEPAM IN THE PREVENTION OF RECURRENT FEBRILE SEIZURES

    Directory of Open Access Journals (Sweden)

    Touran MAHMOUDIAN

    2010-10-01

    Full Text Available ObjectiveTo evaluate the efficacy and common side effects of intermittent clonazepam in febrile  seizures.Materials & MethodsThis study was an experimental trial designed to determine the efficacy of intermittent clonazepam in febrile seizures .Thirty patients with an age range of 6 months to 5 years (60% male, 40% female were studied. Children with a history of psychomotor delay, abnormal  neurological examination, a history of antiepileptic drug consumption, and afebrile seizures were excluded from the study. Patients received a single dose of prophylactic Clonazepam (0.05 mg/kg/ day on the first day of febrile illness and twice daily during the course of fever.An antipyretic medication (Acetaminophen was advised if fever exceeded 38oC. Patients were followed up for one year after the study inclusion date.ResultsThree patients were excluded from study since they didnot follow the tritment and three patients experienced afebrile seizures. Twenty four patients had 162 febrile episodes during the course of the study and all patients were seizure-free after 1 year.ConclusionClonazepam was 100% effective but lethargy and ataxia were common side effects in patients. Fortunately, their parents continued treatment because they had prior awareness of the  possible side effects of clonazepam. Clonazepam is efficacious as an intermittent therapy for febrile seizures if parents are informed of its side effects.Keywords: recurrent febrile seizures, clonazepam, intermittent prophylaxis

  14. The oxidative and antioxidative status of simple febrile seizure patients

    International Nuclear Information System (INIS)

    Objective: To evaluate the oxidative status following a seizure in children experiencing a simple febrile seizure. Methods: The cross-sectional study was conducted at Harran University, Turkey, between January and September 2011. It comprised 32 paediatric patients who, within the preceding 8 hours, had experienced a seizure due to upper respiratory tract infection and had been diagnosed with simple febrile seizure, and 30 healthy children as the control group. Blood was taken from the patients 8 hours after the seizure. Total oxidant level and Total anti-oxidant level were measured according to the Erel technique and the oxidative stress index was calculated. Data was analysed using SPSS 11.5. Results: The mean values of the total oxidant level and the oxidative stress index of the cases were found to be significantly high compared to the controls and the total anti-oxidant level was found to be significantly low (p<0.01, p<0.01, p<0.03 respectively). Conclusion: The increased total oxidant level and decreased total anti-oxidant level resulting in increased oxidative stress associated with febrile seizure patients may increase the risk of experiencing febrile seizures. (author)

  15. Seizure in later life: an ode to the elderly

    Directory of Open Access Journals (Sweden)

    Raminderpal Singh Sibia

    2014-08-01

    Methods: This retrospective study was conducted from medical records of 227 cases of elderly subjects presenting with seizure to emergency department, during a period of 3 years (2010-2013. Results: Most common age group involved was 65-75 years. Mean age of subjects included in the study was 68.13 +/- 23.38 years. The most common etiology was cerebrovascular disorders 132 (58.14%, followed by CNS tumor in 16 (07.04%, hypoglycemia in 14 (06.16%, infections 14 (06.16%, substance abuse 12 (05.28% and trauma 10 (04.40%. The most common presentation was with focal seizures, with 119 (52.42% subjects whereas 82 (36.12% presented with generalized tonic clonic seizure, 20 (08.81% with generalized tonic seizure and 05 (02.20% with absence seizures. Conclusion: The present study aims at pointing out the different clinical features and etiologies of geriatric seizures, thereby lets the reader have a head start with the management of an elderly patient presenting with seizure. [Int J Res Med Sci 2014; 2(4.000: 1393-1395

  16. A case of seizures induced by abstract reasoning.

    Science.gov (United States)

    Tatsuzawa, Yasutaka; Yoshino, Aihide; Nomura, Soichiro

    2010-04-01

    We describe a case of reflex seizures induced by abstract reasoning but not other cognitive processes. The patient, a 46-year-old man, experienced myoclonic seizures whenever he played shogi (Japanese chess). To identify the critical thought processes responsible for inducing his seizures, we monitored his clinical seizures and epileptiform discharges while he performed comprehensive neuropsychological tests, including the Wechsler Adult Intelligence Scale-Revised (WAIS-R), spatial working memory, mental rotation, and Wisconsin Card Sorting Test (WCST) tasks. A myoclonic seizure occurred only during the WCST. Generalized 3- to 5-Hz spike-and-slow-wave bursts occurred repeatedly during the Block Design subtest of the WAIS-R and the WCST, whereas no discharges occurred during other subtests of the WAIS-R including the calculation, spatial working memory, and mental rotation tasks. These results indicate that abstract reasoning, independent of other cognitive processes, could induce the patient's epileptiform discharges, suggesting that his reflex seizures might be a distinct subtype of nonverbal thinking-induced seizures. PMID:20171146

  17. Seizure suppression by gain-of-function escargot mutations.

    Science.gov (United States)

    Hekmat-Scafe, Daria S; Dang, Kim N; Tanouye, Mark A

    2005-03-01

    Suppressor mutations provide potentially powerful tools for examining mechanisms underlying neurological disorders and identifying novel targets for pharmacological intervention. Here we describe mutations that suppress seizures in a Drosophila model of human epilepsy. A screen utilizing the Drosophila easily shocked (eas) "epilepsy" mutant identified dominant suppressors of seizure sensitivity. Among several mutations identified, neuronal escargot (esg) reduced eas seizures almost 90%. The esg gene encodes a member of the snail family of transcription factors. Whereas esg is normally expressed in a limited number of neurons during a defined period of nervous system development, here normal esg was expressed in all neurons and throughout development. This greatly ameliorated both the electrophysiological and the behavioral epilepsy phenotypes of eas. Neuronal esg appears to act as a general seizure suppressor in the Drosophila epilepsy model as it reduces the susceptibility of several seizure-prone mutants. We observed that esg must be ectopically expressed during nervous system development to reduce seizure susceptibility in adults. Furthermore, induction of esg in a small subset of neurons (interneurons) will reduce seizure susceptibility. A combination of microarray and computational analyses revealed 100 genes that represent possible targets of neuronal esg. We anticipate that some of these genes may ultimately serve as targets for novel antiepileptic drugs. PMID:15654097

  18. Variational data assimilation problem for the Baltic Sea thermodynamics

    Science.gov (United States)

    Zakharova, Natalia; Agoshkov, Valery; Parmuzin, Eugene

    2015-04-01

    The most versatile and promising technology for solving problems of monitoring and analysis of the natural environment is a four-dimensional variational data assimilation of observation data. In such problems not only the development and justification of algorithms for numerical solution of variational data assimilation problems but the properties of the optimal solution play an important role. In this work the variational data assimilation problems in the Baltic Sea water area were formulated and studied. Numerical experiments on restoring the ocean heat flux and obtaining solution of the system (temperature, salinity, velocity, and sea surface height) in the Baltic Sea primitive equation hydrodynamics model with assimilation procedure were carried out. In the calculations we used daily sea surface temperature observation from Danish meteorological Institute, prepared on the basis of measurements of the radiometer (AVHRR, AATSR and AMSRE) and spectroradiometer (SEVIRI and MODIS). The spatial resolution of the model grid with respect to the horizontal variables amounted to 0.0625x0.03125 degree. The results of the numerical experiments are presented. This study was supported by the Russian Foundation for Basic Research (project 13-01-00753, project 14-01-31195) and project 14-11-00609 by the Russian Science Foundation. References: 1 E.I. Parmuzin, V.I. Agoshkov, Numerical solution of the variational assimilation problem for sea surface temperature in the model of the Black Sea dynamics. Russ. J. Numer. Anal. Math. Modelling (2012) 27, No.1, 69-94 2 Zakharova N.B., Agoshkov V.I., Parmuzin E.I., The new method of ARGO buoys system observation data interpolation. Russian Journal of Numerical Analysis and Mathematical Modelling. Vol. 28, Issue 1, 2013. 3 Zalesny V.B., Gusev A.V., Chernobay S.Yu., Aps R., Tamsalu R., Kujala P., Rytkönen J. The Bal-tic Sea circulation modelling and assessment of marine pollution, Russ. J. Numer. Analysis and Math. Modelling, 2014, V 29

  19. Approach To The First Unprovoked Seizure- PART II

    Directory of Open Access Journals (Sweden)

    Mohammad GHOFRANI

    2013-11-01

    Full Text Available How to Cite This Article: Ghofrani M. Approach To The First Unprovoked Seizure- PART II. Iran J Child Neurol. 2013 Autumn; 7(4:1-5.Abstract The approach to a child who has experienced a first unprovoked generalized tonic-clonic seizure is challenging and at the same time controversial.How to establish the diagnosis, ways and means of investigation and whether treatment is appropriate, are different aspects of this subject. In this writing the above mentioned matters are discussed. References31.Berg AT, Testa FM., Levy SR, Shinnar S. Neuroimaging in children with newly diagnosed epilepsy. A community based study. Pediatrics 2000;106:527-532.32.Shinnar S, Odell C. Treating childhood seizure; when and for how long. In: Shinnar S, Amir N, Branski D (Eds. Childhood seizure. S Karger Basel. 1995. P.100-110.33.Shinnar S, Berg AT, Moshe Sl, et al. Risk of Seizure recurrence following a first unprovoked seizure in childhood; A prospective study. Pediatrics 1990;85:1076-2085.34.Shinnar S, Berg At, Moshe SL, et al. The risk of seizure recurrence after a first unprovoked febrile seizure in childhood: An extended follow up. Pediatrics 1996:98:216-225.35.Hauser WA, Rich SS, Annegers JF, Anderson VE. Seizure recurrence after a first unprovoked seizure: An extended follow up. Neurology 1990;40:1163-1170.36.Stroink H, Brouwer O F, Arts WF, Greets AT, Peter AC, Van Donselaar CA. The First unprovoked, untreated seizure in childhood: A hospital based study of the accuracy of diagnosis, rate of recurrence, and long term outcome after recurrence. Dutch study of epilepsy in childhood. J Neurol Neurosurg Psychiatry 1998;64:595-600. 37.Shinnar S, Berg AT, O’Dell C. Newstein D, et al. Predictors of multiple seizure in a cohort of children prospectively followed from the time of their first unprovoked seizure, Ann Neurol 2000; 48:140-147.38.Martinovie Z, Jovic N. Seizure recurrence after a first generalized tonic-clonic seizure in children

  20. Automatic Epileptic Seizure Onset Detection Using Matching Pursuit

    DEFF Research Database (Denmark)

    Sorensen, Thomas Lynggaard; Olsen, Ulrich L.; Conradsen, Isa;

    2010-01-01

    An automatic alarm system for detecting epileptic seizure onsets could be of great assistance to patients and medical staff. A novel approach is proposed using the Matching Pursuit algorithm as a feature extractor combined with the Support Vector Machine (SVM) as a classifier for this purpose. The...... combination of Matching Pursuit and SVM for automatic seizure detection has never been tested before, making this a pilot study. Data from red different patients with 6 to 49 seizures are used to test our model. Three patients are recorded with scalp electroencephalography (sEEG) and three with intracranial...

  1. A new approach towards predictability of epileptic seizures: KLT dimension.

    Science.gov (United States)

    Venugopal, Rajeshkumar; Narayanan, K; Prasad, Awadhesh; Spanias, A; Sackellares, J C; Iasemidis, L D

    2003-01-01

    This paper proposes a measure of complexity of the epileptic electroencephalogram (EEG) based on the dimensionality of the Karhunen-Loeve Transform (KLT) in the time domain. We estimate the KLT dimensionality by assuming the same observation noise level in the EEG during the interictal period (between the seizures) as the one during an epileptic seizure (ictal period). Utilizing an optimality criterion based on the T-index [1] and the predictability time, derived from the created KLT dimensionality profiles, we show that 10 out of 15 seizures in one patient with temporal lobe epilepsy were predictable with an average predictability time of about 36 minutes. PMID:12724880

  2. Clinical decision making in seizures and status epilepticus.

    Science.gov (United States)

    Teran, Felipe; Harper-Kirksey, Katrina; Jagoda, Andy

    2015-01-01

    Seizures and status epilepticus are frequent neurologic emergencies in the emergency department, accounting for 1% of all emergency department visits. The management of this time-sensitive and potentially life-threatening condition is challenging for both prehospital providers and emergency clinicians. The approach to seizing patients begins with differentiating seizure activity from mimics and follows with identifying potential secondary etiologies, such as alcohol-related seizures. The approach to the patient in status epilepticus and the patient with nonconvulsive status epilepticus constitutes a special clinical challenge. This review summarizes the best available evidence and recommendations regarding diagnosis and resuscitation of the seizing patient in the emergency setting. PMID:25902572

  3. A database of synthetic observations for geomagnetic data assimilation practice

    Science.gov (United States)

    Fournier, A.; Aubert, J.; Thebault, E.; Schaeffer, N.

    2012-04-01

    Data assimilation aims at producing an optimal estimate of the state of the dynamical system one is interested in by combining two sources of information : physical laws (in the form of a numerical model) and observations. A mandatory step during the development of a data assimilation framework involves a validation phase using synthetic data. In this well-controlled environment, the true dynamical trajectory of the system is known (it results from the integration of the numerical model), and it is used to generate synthetic observations. Those are subsequently used to assess the efficacy, and to highlight possible shortcomings, of the chosen methodology. Data assimilation has recently come to the fore in geomagnetism (e.g. Fournier et al., 2010), a surge motivated by our increased ability to observe the geomagnetic field (thanks to dedicated satellite missions), and by the concurrent progress in the numerical description of core dynamics. Open questions are related to the type of physical models one should resort to, and to the choice of a suitable algorithm, able to integrate the highly heterogeneous geomagnetic record at our disposal, and to deal with the non-linearities of the problem at hand (e.g. Aubert & Fournier, 2011; Fournier et al., 2011). Here we report on the construction of a database of synthetic observations meant at reproducing the heterogeneity of the geomagnetic record (in terms of temporal and spatial coverage). This database relies on two dynamical trajectories: a long-term dynamical trajectory (spanning the equivalent of the past few millenia) computed from a three-dimensional, convection-driven, dynamo model, able to represent accurately the long-term variability of the geomagnetic field a short-term dynamical trajectory (spanning the equivalent of a few decades), computed from a high-resolution three-dimensional model, able to represent interannual to decadal core processes (e.g. Gillet et al., 2011), and whose basic state is determined from

  4. Assimilating in-situ Measurements into a Reduced-Dimensionality Model of an Estuary- Plume System.

    Science.gov (United States)

    Frolov, S.; Baptista, A.; Leen, T.; Lu, Z.; van der Merwe, R.

    2006-12-01

    A very fast, model independent, fully non-linear extension to the reduced space Kalman filter has been recently proposed and demonstrated for the assimilation of the non-linear circulation in both a synthetic estuary and in the river-dominated Columbia River estuary. Here, we extend the application to another complex problem the simulation of a coupled estuary-plume system. Our data assimilation method is based on the same three stages as in our previous work: (1) generate a database of hindcast runs with a forward numerical circulation model like SELFE; (2) use examples from the hindcast database to train a fast, non-linear neural network model surrogate that approximates the dynamics of the forward model; and (3) use a Sigma Point Kalman filter, incorporating the model surrogate dynamics, to estimate the true state of the system. Both model surrogates (2) and state estimation (3) operate in the reduced space spanned by the Empirical Orthogonal Functions (EOFs, aka principal components). The key modifications that we are introducing are the improved EOF analysis for more accurate dimension reduction in the plume region, a more compact noise model for faster DA, and the improved treatment of wetting and drying. The resulting data assimilation system is ~100 faster than the forward model and ~10000 faster than the existing variational and sequential methods for data assimilation. As a test of the system, we assimilate in-situ data from four offshore moorings and 14 estuarine stations during May-September of 2004. For validation of the experiments we use cross-validation against in-situ data, data from research cruises, and satellite imagery. We show that data assimilation is effective for improving the simulation of at least three highly non-linear processes: the dynamics of the estuarine salt-wedge, the response of the plume to wind shifts, the propagation of the shallow water tides, and wetting and drying of tidal flats.

  5. The social context of assimilation: testing implications of segmented assimilation theory.

    Science.gov (United States)

    Xie, Yu; Greenman, Emily

    2011-05-01

    Segmented assimilation theory has been a popular explanation for the diverse experiences of assimilation among new waves of immigrants and their children. While the theory has been interpreted in many different ways, we emphasize its implications for the important role of social context: both processes and consequences of assimilation should depend on the local social context in which immigrants are embedded. We derive empirically falsifiable hypotheses about the interaction effects between social context and assimilation on immigrant children's well-being. We then test the hypotheses using data from the National Longitudinal Study of Adolescent Health. Our empirical analyses yield two main findings. First, for immigrant adolescents living in non-poverty neighborhoods, we find assimilation to be positively associated with educational achievement and psychological well-being but also positively associated with at-risk behavior. Second, there is little empirical evidence supporting our hypotheses derived from segmented assimilation theory. We interpret these results to mean that future research would be more fruitful focusing on differential processes of assimilation rather than differential consequences of assimilation. PMID:21572546

  6. Assimilation of the Microwave Limb Sounder Radiances

    Science.gov (United States)

    Wargan, K.; Read, W.; Livesey, N.; Wagner, P.; Nguyen. H.; Pawson, S.

    2012-01-01

    It has been shown that the assimilation of limb-sounder data can significantly improve the representation of ozone in NASA's GEOS Data Assimilation Systems (GEOS-DAS), particularly in the stratosphere. The studies conducted so far utilized retrieved data from the MIPAS, POAM, ILAS and EOS Microwave Limb Sounder (EOS MLS) instruments. Direct assimilation of the radiance data can be seen as the natural next step to those studies. The motivation behind working with radiances is twofold. First, retrieval algorithms use a priori data which are either climatological or are obtained from previous analyses. This introduces additional uncertainty and, in some cases, may lead to "self-contamination"- when the a priori is taken from the same assimilation system in which subsequently ingests the retrieved observations. Second, radiances can be available in near real time thus providing an opportunity for operational assimilation, which could help improve the use of infrared radiance instruments from operational satellite instruments. In this presentation we summarize our ongoing work on an implementation of the assimilation of EOS MLS radiances into the GEOS-5 DAS. This work focuses on assimilation of band 7 brightness temperatures which are sensitive to ozone. Our implementation uses the MLS Callable Forward Model developed by the MLS team at NASA JPL as the observation operator. We will describe our approach and recent results which are not yet final. In particular, we will demonstrate that this approach has a potential to improve the vertical structure of ozone in the lower tropical stratosphere as compared with the retrieved MLS product. We will discuss the computational efficiency of this implementation.

  7. Increased Seizure Latency and Decreased Severity of Pentylenetetrazol-Induced Seizures in Mice after Essential Oil Administration

    Directory of Open Access Journals (Sweden)

    Eleni Koutroumanidou

    2013-01-01

    Full Text Available The effect of pretreatment with essential oils (EOs from eight aromatic plants on the seizure latency and severity of pentylenetetrazol- (PTZ- induced seizures in mice was evaluated. Weight-dependent doses of Rosmarinus officinalis, Ocimum basilicum, Mentha spicata, Mentha pulegium, Lavandula angustifolia, Mentha piperita, Origanum dictamnus, and Origanum vulgare, isolated from the respective aromatic plants from NE Greece, were administered 60 minutes prior to intraperitoneal (i.p. injection of a lethal dose of PTZ to eight respective groups of Balb-c mice. Control group received only one i.p. PTZ injection. Motor and behavioral activity of the animals after EOs administration, development of tonic-clonic seizures, seizure latency and severity, and percentage of survival after PTZ administration were determined for each group. All groups of mice treated with the EOs showed reduced activity and stability after the administration of the oil, except for those treated with O. vulgare (100% mortality after the administration of the oil. After PTZ administration, mice from the different groups showed increased latency and reduced severity of seizures (ranging from simple twitches to complete seizures. Mice who had received M. piperita demonstrated no seizures and 100% survival. The different drastic component and its concentration could account for the diversity of anticonvulsant effects.

  8. Increased seizure latency and decreased severity of pentylenetetrazol-induced seizures in mice after essential oil administration.

    Science.gov (United States)

    Koutroumanidou, Eleni; Kimbaris, Athanasios; Kortsaris, Alexandros; Bezirtzoglou, Eugenia; Polissiou, Moschos; Charalabopoulos, Konstantinos; Pagonopoulou, Olga

    2013-01-01

    The effect of pretreatment with essential oils (EOs) from eight aromatic plants on the seizure latency and severity of pentylenetetrazol- (PTZ-) induced seizures in mice was evaluated. Weight-dependent doses of Rosmarinus officinalis, Ocimum basilicum, Mentha spicata, Mentha pulegium, Lavandula angustifolia, Mentha piperita, Origanum dictamnus, and Origanum vulgare, isolated from the respective aromatic plants from NE Greece, were administered 60 minutes prior to intraperitoneal (i.p.) injection of a lethal dose of PTZ to eight respective groups of Balb-c mice. Control group received only one i.p. PTZ injection. Motor and behavioral activity of the animals after EOs administration, development of tonic-clonic seizures, seizure latency and severity, and percentage of survival after PTZ administration were determined for each group. All groups of mice treated with the EOs showed reduced activity and stability after the administration of the oil, except for those treated with O. vulgare (100% mortality after the administration of the oil). After PTZ administration, mice from the different groups showed increased latency and reduced severity of seizures (ranging from simple twitches to complete seizures). Mice who had received M. piperita demonstrated no seizures and 100% survival. The different drastic component and its concentration could account for the diversity of anticonvulsant effects. PMID:23819045

  9. Blockade of T-type calcium channels prevents tonic-clonic seizures in a maximal electroshock seizure model.

    Science.gov (United States)

    Sakkaki, Sophie; Gangarossa, Giuseppe; Lerat, Benoit; Françon, Dominique; Forichon, Luc; Chemin, Jean; Valjent, Emmanuel; Lerner-Natoli, Mireille; Lory, Philippe

    2016-02-01

    T-type (Cav3) calcium channels play important roles in neuronal excitability, both in normal and pathological activities of the brain. In particular, they contribute to hyper-excitability disorders such as epilepsy. Here we have characterized the anticonvulsant properties of TTA-A2, a selective T-type channel blocker, in mouse. Using the maximal electroshock seizure (MES) as a model of tonic-clonic generalized seizures, we report that mice treated with TTA-A2 (0.3 mg/kg and higher doses) were significantly protected against tonic seizures. Although no major change in Local Field Potential (LFP) pattern was observed during the MES seizure, analysis of the late post-ictal period revealed a significant increase in the delta frequency power in animals treated with TTA-A2. Similar results were obtained for Cav3.1-/- mice, which were less prone to develop tonic seizures in the MES test, but not for Cav3.2-/- mice. Analysis of extracellular signal-regulated kinase 1/2 (ERK) phosphorylation and c-Fos expression revealed a rapid and elevated neuronal activation in the hippocampus following MES clonic seizures, which was unchanged in TTA-A2 treated animals. Overall, our data indicate that TTA-A2 is a potent anticonvulsant and that the Cav3.1 isoform plays a prominent role in mediating TTA-A2 tonic seizure protection. PMID:26456350

  10. Experimental febrile seizures are precipitated by a hyperthermia-induced respiratory alkalosis

    OpenAIRE

    Schuchmann, Sebastian; Schmitz, Dietmar; Rivera, Claudio; Vanhatalo, Sampsa; Salmen, Benedikt; Mackie, Ken; Sipilä, Sampsa T; Voipio, Juha; Kaila, Kai

    2006-01-01

    Febrile seizures are frequent during early childhood, and prolonged (complex) febrile seizures are associated with an increased susceptibility to temporal lobe epilepsy. The pathophysiological consequences of febrile seizures have been extensively studied in rat pups exposed to hyperthermia. The mechanisms that trigger these seizures are unknown, however. A rise in brain pH is kn...

  11. Effect of Immunotherapy on Seizure Outcome in Patients with Autoimmune Encephalitis: A Prospective Observational Registry Study.

    Directory of Open Access Journals (Sweden)

    Jung-Ick Byun

    Full Text Available To evaluate the seizure characteristics and outcome after immunotherapy in adult patients with autoimmune encephalitis (AE and new-onset seizure.Adult (age ≥18 years patients with AE and new-onset seizure who underwent immunotherapy and were followed-up for at least 6 months were included. Seizure frequency was evaluated at 2-4 weeks and 6 months after the onset of the initial immunotherapy and was categorized as "seizure remission", "> 50% seizure reduction", or "no change" based on the degree of its decrease.Forty-one AE patients who presented with new-onset seizure were analysed. At 2-4 weeks after the initial immunotherapy, 51.2% of the patients were seizure free, and 24.4% had significant seizure reduction. At 6 months, seizure remission was observed in 73.2% of the patients, although four patients died during hospitalization. Rituximab was used as a second-line immunotherapy in 12 patients who continued to have seizures despite the initial immunotherapy, and additional seizure remission was achieved in 66.6% of them. In particular, those who exhibited partial response to the initial immunotherapy had a better seizure outcome after rituximab, with low adverse events.AE frequently presented as seizure, but only 18.9% of the living patients suffered from seizure at 6 months after immunotherapy. Aggressive immunotherapy can improve seizure outcome in patients with AE.

  12. Diagnostic decision-making after a first and recurrent seizure in adults

    NARCIS (Netherlands)

    Askamp, J.; Putten, van M.J.A.M.

    2013-01-01

    Purpose The role of EEG after a first seizure has been debated. Epileptiform EEG activity is a good predictor of seizure recurrence, but is reported in only 8-50% of first-seizure adult patients. Even if the EEG is abnormal, the opinions about treatment after a first seizure differ. The role of EEG

  13. Relation between stress-precipitated seizures and the stress response in childhood epilepsy

    NARCIS (Netherlands)

    Van Campen, Jolien S.; Jansen, Floor E.; Pet, Milou A.; Otte, Willem M.; Hillegers, Manon H J; Joels, Marian; Braun, Kees P J

    2015-01-01

    The majority of patients with epilepsy report that seizures are sometimes triggered or provoked. Stress is the most frequently self-reported seizure-precipitant. The mechanisms underlying stress-sensitivity of seizures are currently unresolved. We hypothesized that stress-sensitivity of seizures rel

  14. GENERALIZED VARIATIONAL DATA ASSIMILATION METHOD AND NUMERICAL EXPERIMENT FOR NON-DIFFERENTIAL SYSTEM

    Institute of Scientific and Technical Information of China (English)

    黄思训; 杜华栋; 韩威

    2004-01-01

    The generalized variational data assimilation for non-differential dynamical systems is studied.There is no tangent linear model for non-differential systems and thus the general adjoint model can not be derived in the traditional way.The weak form of the original system was introduced, and then the generalized adjoint model was derived. The generalized variational data assimilation methods were developed for non-differential low dimensional system and non-differential high dimensional system with global and local observations. Furthermore, ideas in inverse problems are introduced to 4DVAR (Four-dimensional variational) of non-differential partial differential system with local observations.

  15. Influence of assimilating transports and in situ data from the Rapid-MOCHA array into the GECCO2 ocean synthesis

    Science.gov (United States)

    Köhl, Armin

    2015-12-01

    By assimilating information required for the estimation of the Atlantic meridional overturning circulation (AMOC) by the Rapid-MOCHA array, we investigate how transports should be constrained. For the period 2004-2011, we find that even the large adjustments in Florida Strait transport (FST) imposed by assimilating FST data do not impact the AMOC strength at 26.5° N while the AMOC away from this section changes due to the baroclinic response. Moreover, the high correlation between the FST and AMOC previously reported cannot be confirmed for this longer period. When assimilating FST and AMOC transports in conjunction, simulated transports can both be brought easily into consistency with the Rapid estimates while the representation of the hydrographic data at the mooring locations improves mainly at the eastern boundary. The dynamical constraint through the equations of motion conditions that the errors of the components are correlated and the total AMOC error is a much smaller than the sum of its components. Although Ekman and mid-ocean transports improve when AMOC is assimilated, the excellent AMOC representation relies on error compensation through adjustments of mainly the Ekman component. Assimilating the mooring data together with FST does not improve the representation of the AMOC. Density information is difficult to extract via assimilating temperature and salinity because of the strong density compensation in the subtropical gyre. Alternatively assimilating density from the mooring data directly was of limited success.

  16. Quantifying Interannual Variability of the UTLS Ozone Using Assimilation of Satellite Data

    Science.gov (United States)

    Wargan, K.; Pawson, S.; Olsen, M.; Douglass, A.; Witte, J.; Strahan, S.; Bharitia, P. K.

    2012-01-01

    An accurate representation of spatial and temporal variability of the Upper Troposphere Lower Stratosphere (UTLS) ozone is essential for understanding both the tropospheric ozone budget and ozone s contribution to radiative forcing. The complex, dynamically driven structure of trace gas fields in the UTLS presents a challenge to data-based and modelling studies. Small features are not fully resolved in data from limb-sounding instruments such as the Microwave Limb Sounder on EOS-Aura (the EOS-MLS), but are captured in assimilation of those data as vertical structure is added from the assimilated meteorology. This will be demonstrated using a multi-year assimilation of EOS-MLS observations in the Goddard Earth Observing System, Version 5 (GEOS-5) data assimilation system. The results demonstrate the realism of the seasonal and year to year variability of laminar structures in the mid-latitudinal ozone field between years 2005-2007, for which independent validation data are available from the HIRDLS instrument. The analysis is done in the context of the underlying large scale dynamics. The lifetimes of most research instruments are too short for them to be used throughout the duration of long-term (at least 3 decades) reanalyses. For example, the EOS-MLS instrument has operated since mid-2004 until present. By contrast, Solar Backscatter Ultra Violet (SBUV) measurements provide continuous data since late 1978, but their vertical resolution is insufficient to represent the profile shape in the UTLS. Assimilation of these SBUV/2 observations in the GEOS-5 data assimilation system has hitherto not captured a realistic ozone structure in the UTLS, even though transport studies using GEOS-5 wind fields do show such structures. We show that careful construction of the background error covariance structure in GEOS-5 can lead to more realistic UTLS ozone fields when assimilating SBUV/2 observations. The reasoning behind this will be discussed, emphasizing the need to retain

  17. CHOLESTEROL ASSIMILATION BY COMMERCIAL YOGHURT STARTER CULTURES

    Directory of Open Access Journals (Sweden)

    Małgorzata Ziarno

    2007-03-01

    Full Text Available The ability to in vitro cholesterol level reduction in laboratory media has been shown for numerous strains of lactic acid bacteria, but not for all strains of lactic bacteria used in the dairy industry. The aim of this work was the determination of the ability of selected thermophilic lactic acid bacteria to cholesterol assimilation during 24 h culture in MRS broth. Commercial starter cultures showed various ability to cholesterol assimilation from laboratory medium. In case of starter cultures used for production of traditional yoghurt, consisting of Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, the quantity of assimilated cholesterol did not exceed 27% of its initial contents (0.7 g in 1 dm3. Starter cultures used for bioyoghurt production, containing also probiotic strains (came from Lactobacillus acidophilus species or Bifidobacterium genus assimilated from almost 18% to over 38% of cholesterol. For one monoculture of Lb. acidophilus, cholesterol assimilation ability of 49-55% was observed, despite that the number of bacterial cells in this culture was not different from number of bacteria in other cultures.

  18. Estimating Evapotranspiration with Land Data Assimilation Systems

    Science.gov (United States)

    Peters-Lidard, C. D.; Kumar, S. V.; Mocko, D. M.; Tian, Y.

    2011-01-01

    Advancements in both land surface models (LSM) and land surface data assimilation, especially over the last decade, have substantially advanced the ability of land data assimilation systems (LDAS) to estimate evapotranspiration (ET). This article provides a historical perspective on international LSM intercomparison efforts and the development of LDAS systems, both of which have improved LSM ET skill. In addition, an assessment of ET estimates for current LDAS systems is provided along with current research that demonstrates improvement in LSM ET estimates due to assimilating satellite-based soil moisture products. Using the Ensemble Kalman Filter in the Land Information System, we assimilate both NASA and Land Parameter Retrieval Model (LPRM) soil moisture products into the Noah LSM Version 3.2 with the North American LDAS phase 2 (NLDAS-2) forcing to mimic the NLDAS-2 configuration. Through comparisons with two global reference ET products, one based on interpolated flux tower data and one from a new satellite ET algorithm, over the NLDAS2 domain, we demonstrate improvement in ET estimates only when assimilating the LPRM soil moisture product.

  19. Epileptiform EEG Discharges and Risk of Epilepsy Following Febrile Seizure

    OpenAIRE

    J Gordon Millichap

    2013-01-01

    Investigators at Kangnam and Masan Samsung Changwon Hospitals, Korea, studied the relation between epileptiform discharges on the EEG after febrile seizures (FS) and the risk of developing epilepsy and recurrence of FS.

  20. Disparity in regional cerebral blood flow during electrically induced seizure

    DEFF Research Database (Denmark)

    Sestoft, D; Meden, P; Hemmingsen, R; Hancke, B; Madsen, P L; Friberg, L

    1993-01-01

    This is a presentation of 2 cases in which the intraictal regional cerebral blood flow distribution was measured with the 99mTc-HMPAO single photon emission computerized tomography technique during an electrically induced seizure. Although the seizure was verified as generalized on electroencepha......This is a presentation of 2 cases in which the intraictal regional cerebral blood flow distribution was measured with the 99mTc-HMPAO single photon emission computerized tomography technique during an electrically induced seizure. Although the seizure was verified as generalized on...... electroencephalography, the regional neuronal activity expressed as rCBF unexpectedly was markedly asymmetrical in one of the cases. These findings demonstrated that the 99mTc-HMPAO technique makes it possible to discriminate intraictal variation in cortical and subcortical activation between the hemispheres during...

  1. Recurrent seizures: An unusual manifestation of vitamin B12 deficiency

    Directory of Open Access Journals (Sweden)

    Kumar S

    2004-01-01

    Full Text Available The present report highlights an unusual presentation of vitamin B12 deficiency— recurrent seizures in a 26-year-old man. His symptoms responded to parenteral vitamin B12 therapy. The relevant literature is reviewed.

  2. Ontology and Knowledge Management System on Epilepsy and Epileptic Seizures

    CERN Document Server

    Almeida, Pedro; Sales, Francisco; Nogueira, Ana; Dourado, António

    2010-01-01

    A Knowledge Management System developed for supporting creation, capture, storage and dissemination of information about Epilepsy and Epileptic Seizures is presented. We present an Ontology on Epilepsy and a Web-based prototype that together create the KMS.

  3. Focal seizure-induced premature myelination: speculation from serial MRI

    International Nuclear Information System (INIS)

    Local changes in the white matter underlying a focus of cortical thickening were monitored using MRI in an epileptic 2-month-old boy. We hypothesise that these changes reflected seizure-induced premature myelination. (orig.) (orig.)

  4. Appearing and disappearing CT scan abnormalities and seizures.

    OpenAIRE

    P K Sethi; Kumar, B.R.; Madan, V S; Mohan, V

    1985-01-01

    A group of patients presenting with seizures (focal or generalised) and abnormal CT scans who, on follow up, showed complete resolution of the CT scan changes, without any treatment other than anticonvulsants, are described.

  5. Focal inhibitory seizures: a cause of recurrent transient weakness.

    Science.gov (United States)

    Chowdhury, Fahmida A; Connor, Steve; Ferner, Rosalie; Leschziner, Guy

    2015-12-01

    Focal seizures are usually manifest with stereotyped positive phenomena. However, seizures may also give negative phenomena, such as paralysis, speech arrest, neglect, atonia and numbness. We report a 39-year-old man with neurofibromatosis 2 who had recurrent stereotyped episodes of weakness affecting his right leg and right arm. His MR scan of brain showed numerous meningiomas, the largest of which was near the vertex, adjacent to the left side of the falx. Interictal electroencephalogram, MR cerebral angiogram and Doppler carotid artery ultrasound scan were normal. He was diagnosed with epilepsy and started on levetiracetam, with no subsequent attacks. We postulate his negative motor seizures related to a meningioma overlying the supplementary negative motor area in the mesial superior frontal gyrus, and discuss diagnostic criteria for inhibitory seizures. PMID:26245512

  6. Nitric Oxide Regulates Neurogenesis in the Hippocampus following Seizures

    Directory of Open Access Journals (Sweden)

    Bruno P. Carreira

    2015-01-01

    Full Text Available Hippocampal neurogenesis is changed by brain injury. When neuroinflammation accompanies injury, activation of resident microglial cells promotes the release of inflammatory cytokines and reactive oxygen/nitrogen species like nitric oxide (NO. In these conditions, NO promotes proliferation of neural stem cells (NSC in the hippocampus. However, little is known about the role of NO in the survival and differentiation of newborn cells in the injured dentate gyrus. Here we investigated the role of NO following seizures in the regulation of proliferation, migration, differentiation, and survival of NSC in the hippocampus using the kainic acid (KA induced seizure mouse model. We show that NO increased the proliferation of NSC and the number of neuroblasts following seizures but was detrimental to the survival of newborn neurons. NO was also required for the maintenance of long-term neuroinflammation. Taken together, our data show that NO positively contributes to the initial stages of neurogenesis following seizures but compromises survival of newborn neurons.

  7. Maternal thyroid dysfunction and risk of seizure in the child

    DEFF Research Database (Denmark)

    Andersen, Stine Linding; Laurberg, Peter; Wu, Chun Sen;

    2013-01-01

    Thyroid hormones are essential for brain development, and maternal thyroid disease may affect child neurocognitive development. Some types of seizures may also depend upon early exposure of the developing central nervous system, and we hypothesized that maternal thyroid dysfunction could increase...... the risk of seizure in the child. In a Danish population-based study we included 1,699,693 liveborn singletons, and from the Danish National Hospital Register we obtained information on maternal diagnosis of hyper- or hypothyroidism and neonatal seizure, febrile seizure, and epilepsy in the child....... Maternal diagnosis of thyroid dysfunction before or after birth of the child was registered in two percent of the singleton births. In adjusted analyses, maternal hyperthyroidism and hypothyroidism first time diagnosed after birth of the child were associated with a significant increased risk of epilepsy...

  8. Experimenting with the GMAO 4D Data Assimilation

    Science.gov (United States)

    Todling, R.; El Akkraoui, A.; Errico, R. M.; Guo, J.; Kim, J.; Kliest, D.; Parrish, D. F.; Suarez, M.; Trayanov, A.; Tremolet, Yannick; Whitaker, J.

    2012-01-01

    The Global Modeling and Assimilation Office (GMAO) has been working to promote its prototype four-dimensional variational (4DVAR) system to a version that can be exercised at operationally desirable configurations. Beyond a general circulation model (GeM) and an analysis system, traditional 4DV AR requires availability of tangent linear (TL) and adjoint (AD) models of the corresponding GeM. The GMAO prototype 4DVAR uses the finite-volume-based GEOS GeM and the Grid-point Statistical Interpolation (GSI) system for the first two, and TL and AD models derived ITom an early version of the finite-volume hydrodynamics that is scientifically equivalent to the present GEOS nonlinear GeM but computationally rather outdated. Specifically, the TL and AD models hydrodynamics uses a simple (I-dimensional) latitudinal MPI domain decomposition, which has consequent low scalability and prevents the prototype 4DV AR ITom being used in realistic applications. In the near future, GMAO will be upgrading its operational GEOS GCM (and assimilation system) to use a cubed-sphere-based hydrodynamics. This versions of the dynamics scales to thousands of processes and has led to a decision to re-derive the TL and AD models for this more modern dynamics, thus taking advantage of a two-dimensional MPI decomposition and improved scalability properties. With the aid of the Transformation of Algorithms in FORTRAN (l'AF) automatic adjoint generation tool and some hand-coding, a version of the cubed-sphere-based TL and AD models, with a simplified vertical diffusion scheme, is now available, enabling multiple configurations of standard implementations of 4DV AR in GEOS. Concurrent to this development, collaboration with the National Centers for Environmental Prediction (NCEP) and the Earth System Research Laboratory (ESRL) has allowed GMAO to implement a hybrid-ensemble capability within the GEOS data assimilation system. Both 3Dand 4D-ensemble capabilities are presently available thus allowing

  9. Clinical and psychosocial characteristics of children with nonepileptic seizures

    Directory of Open Access Journals (Sweden)

    Chinta Sri

    2008-01-01

    Full Text Available Objective: The aim of this study is to present a comprehensive profile of clinical and psychosocial characteristics of children with psychogenic nonepileptic seizures and to assess the short-term outcome of these patients. Materials and Methods: The subjects were consecutive cases of children with a diagnosis of nonepileptic seizures (N=17, mean age = 10.7 years, S.D. = 1.26 and two groups of control groups matched on age and sex: true seizure group and healthy controls. All the children were recruited from the out-patient services of the Department of Pediatrics of a tertiary care teaching hospital in North India. Detailed history taking and clinical examination was done in the case of every child. A standard 18 channel EEG was done in all the children and a video EEG was done in 12 cases of children with nonepileptic seizures. The Childhood Psychopathology Measurement Schedule (CPMS and Life Events Scale for Indian Children (LESIC were used to measure the children′s emotional and behavioral functioning at home, and the number of life events and the stress associated with these events in the preceding year and the year before that. Short-term outcome was examined three to six months after the diagnosis of nonepileptic seizures was made. Results: Unresponsiveness without marked motor manifestations was the most common "ictal" characteristic of the nonepileptic seizures. Pelvic thrusting, upper and lower limb movements, head movements, and vocalization were observed in less than one-third of the patients. Increased psychosocial stress and significantly higher number of life events in the preceding year were found to characterize children with nonepileptic seizures, as compared to the two control groups. The nonepileptic seizures and true seizures groups had a higher proportion of children with psychopathology scores in the clinically significant maladjustment range, as compared to those in the healthy control group. A majority of the patients

  10. Randomized, controlled trial of ibuprofen syrup administered during febrile illnesses to prevent febrile seizure recurrences

    OpenAIRE

    van Stuijvenberg, Margriet; Derksen-Lubsen, Gerarda; Steyerberg, Ewout; Habbema, Dik; Moll, Henriëtte

    1998-01-01

    textabstractOBJECTIVES: Febrile seizures recur frequently. Factors increasing the risk of febrile seizure recurrence include young age at onset, family history of febrile seizures, previous recurrent febrile seizures, time lapse since previous seizure /=38.5 degrees C). Parents were instructed to take the child's rectal temperature immediately when the child seemed ill or feverish and to promptly administer the study medication when the temperature was >/=38.5 degrees C. Doses were to be admi...

  11. Unit Activity of Hippocampal Interneurons before Spontaneous Seizures in an Animal Model of Temporal Lobe Epilepsy

    OpenAIRE

    Toyoda, Izumi; Fujita, Satoshi; Thamattoor, Ajoy K.; Buckmaster, Paul S.

    2015-01-01

    Mechanisms of seizure initiation are unclear. To evaluate the possible roles of inhibitory neurons, unit recordings were obtained in the dentate gyrus, CA3, CA1, and subiculum of epileptic pilocarpine-treated rats as they experienced spontaneous seizures. Most interneurons in the dentate gyrus, CA1, and subiculum increased their firing rate before seizures, and did so with significant consistency from seizure to seizure. Identification of CA1 interneuron subtypes based on firing characteristi...

  12. Time to First EEG Seizure During Continuous Video/EEG Telemetry

    OpenAIRE

    Hećimović, Hrvoje; Gilliam, Frank

    2005-01-01

    Correlation between time to first scalp EEG seizure during video/EEG telemetry and self-reported seizure frequency was determined in refractory epilepsy patients. Eighty two consecutive epilepsy patients were preoperatively evaluated, as part of a larger study, during their video/EEG monitoring at the Adult Epilepsy Center at Washington University. Self-reported seizure frequency, time to first seizure in the monitoring unit, and clinical variables of age, sex and seizure focus localization w...

  13. Risk factors for developing epilepsy after neonatal seizures

    OpenAIRE

    2013-01-01

    Neonatal seizures are the most frequent neurological disorder in the neonatal period. The incidence is reported to be higher than at any other period in life. Because of the unique nature of neonatal brain anatomy, connections and the paradoxical nature of neurotransmitters, seizures in this age group vary in semiology from those in older children. They may cause irreversible changes to the synapses in the immature brain and progress to epilepsy. The aim of the study was to analys...

  14. Copeptin as a serum biomarker of febrile seizures.

    Directory of Open Access Journals (Sweden)

    Benjamin Stöcklin

    Full Text Available Accurate diagnosis of febrile seizures in children presenting after paroxysmal episodes associated with fever, is hampered by the lack of objective postictal biomarkers. The aim of our study was to investigate whether FS are associated with increased levels of serum copeptin, a robust marker of arginine vasopressin secretion.This was a prospective emergency-setting cross-sectional study of 161 children between six months and five years of age. Of these, 83 were diagnosed with febrile seizures, 69 had a febrile infection without seizures and nine had epileptic seizures not triggered by infection. Serum copeptin and prolactin levels were measured in addition to standard clinical, neurophysiological, and laboratory assessment.NCT01884766.Circulating copeptin was significantly higher in children with febrile seizures (median [interquartile range] 18.9 pmol/L [8.5-36.6] compared to febrile controls (5.6 pmol/L [4.1-9.4]; p < 0.001, with no differences between febrile and epileptic seizures (21.4 pmol/L [16.1-46.6]; p = 0.728. In a multivariable regression model, seizures were the major determinant of serum copeptin (beta 0.509; p < 0.001, independently of clinical and baseline laboratory indices. The area under the receiver operating curve for copeptin was 0.824 (95% CI 0.753-0.881, significantly higher compared to prolactin (0.667 [0.585-0.742]; p < 0.001. The diagnostic accuracy of copeptin increased with decreasing time elapsed since the convulsive event (at 120 min: 0.879 [0.806-0.932] and at <60 min: 0.975 [0.913-0.997].Circulating copeptin has high diagnostic accuracy in febrile seizures and may be a useful adjunct for accurately diagnosing postictal states in the emergency setting.

  15. A case of Hashimoto's encephalopathy presenting with seizures and psychosis

    OpenAIRE

    Min-Joo Lee; Hae-Sang Lee; Jin-Soon Hwang; Da-Eun Jung

    2012-01-01

    Hashimoto’s encephalopathy (HE) is a rare, poorly understood, autoimmune disease characterized by symptoms of acute or subacute encephalopathy associated with increased anti-thyroid antibody levels. Here, we report a case of a 14-year-old girl with HE and briefly review the literature. The patient presented with acute mental changes and seizures, but no evidence of infectious encephalitis. In the acute stage, the seizures did not respond to conventional antiepileptic drugs, including valproic...

  16. Benign occipital lobe seizures: Natural progression and atypical evolution

    OpenAIRE

    Prithika Chary; Bhuvaneshwari Rajendran

    2013-01-01

    Benign occipital seizure syndromes are benign childhood epilepsy syndromes and are mainly of two types, Panayiotopoulos syndrome, an autonomic epilepsy and idiopathic childhood occipital epilepsy of Gastaut (ICOE-G) including the idiopathic photosensitive occipital lobe epilepsy. Although both these types are categorized as occipital seizures, they are distinct in presentation and management. They can also be tricky to diagnose as visual symptoms may not always be the presenting feature and i...

  17. PREVALENCE OF SEIZURE IN PKU:AN ANALYTIC HISTORICAL STUDY

    OpenAIRE

    Feisal RAHIMPOUR; AALAEI Mohammad Reza; KARIMZADEH, Parvaneh

    2010-01-01

    ObjectivePhenylketonuria (PKU) is an autosomal recessive metabolic genetic disorder characterized by a deficiency in the hepatic enzyme phenylalanine hydroxylase (PAH) which can cause problems with brain development, leading to progressive mental retardation, brain damage, and seizures. In this study we evaluated the frequency of seizure, EEG abnormality and behavioral disorders.Materials & Methods In this case study, 94 PKU children aged between 1 month and 23 years who were referred to Mofi...

  18. Robust Deep Network with Maximum Correntropy Criterion for Seizure Detection

    OpenAIRE

    2014-01-01

    Effective seizure detection from long-term EEG is highly important for seizure diagnosis. Existing methods usually design the feature and classifier individually, while little work has been done for the simultaneous optimization of the two parts. This work proposes a deep network to jointly learn a feature and a classifier so that they could help each other to make the whole system optimal. To deal with the challenge of the impulsive noises and outliers caused by EMG artifacts in EEG signals,...

  19. Automated differentiation between epileptic and non-epileptic convulsive seizures

    DEFF Research Database (Denmark)

    Beniczky, Sándor; Conradsen, Isa; Moldovan, Mihai;

    2015-01-01

    algorithm: 25 generalized tonic-clonic seizures (GTCSs) from 11 patients, and 19 episodes of convulsive PNES from 13 patients. The gold standard was the interpretation of the video-electroencephalographic recordings by experts blinded to the EMG results. The algorithm correctly classified 24 GTCSs (96%) and...... 18 PNESs (95%). The overall diagnostic accuracy was 95%. This algorithm is useful for distinguishing between epileptic and psychogenic convulsive seizures....

  20. A Spectral Based Forecasting Tool of Epileptic Seizures

    Directory of Open Access Journals (Sweden)

    Hedi Khammari

    2012-05-01

    Full Text Available A new approach to recognize and predict succedent epileptic seizure by using single channel electroencephalogram (EEG analysis is proposed. Spectral analysis of a brain time series of the left frontal FP1-F7 (LF scalp location signal is devoted for seizure prediction and analysis. Important findings showing the presence of preictal spectral changes in studied brain signal are described. Spectral features occurring during the preictal epoch are extracted from the application of sliding spectral windows of raw EEG at different moments in time preceding the seizure onset. The same method is then applied to a couple of Intrinsic Mode Functions (IMF1 and IMF2 of the raw EEG (FP1-F7 decomposed by the algorithm of empirical mode decomposition. The main prediction features are derived from the changes of amplitudes, frequency and the number of spikes which are of diagnostic values. The sliding spectral windows were computed to trace the amplitude changes of higher harmonics during time interval preceding the seizure onset. Choosing different moments in time aims to identify the best prediction time of seizure onset. Obviously an early prediction time is always desirable but the seizure may result from an abrupt change and so the spectral 'signs of an imminent seizure occur during a very short prediction time. From another viewpoint, it may be advantageous to consider a successive prediction times showing the increase of spike numbers and the predominance of certain waves rather than others when approaching seizure onset. The common prediction features extracted from the analysis of FP1-F7 signal for both patients were mainly the increasing number of spikes of low frequency waves namely delta and theta waves.

  1. Cannabidiol Rescues Acute Hepatic Toxicity and Seizure Induced by Cocaine

    OpenAIRE

    Luciano Rezende Vilela; Lindisley Ferreira Gomides; Bruna Araújo David; Maísa Mota Antunes; Ariane Barros Diniz; Fabrício de Araújo Moreira; Gustavo Batista Menezes

    2015-01-01

    Cocaine is a commonly abused illicit drug that causes significant morbidity and mortality. The most severe and common complications are seizures, ischemic strokes, myocardial infarction, and acute liver injury. Here, we demonstrated that acute cocaine intoxication promoted seizure along with acute liver damage in mice, with intense inflammatory infiltrate. Considering the protective role of the endocannabinoid system against cell toxicity, we hypothesized that treatment with an anandamide hyd...

  2. Placental ischemia increases seizure susceptibility and cerebrospinal fluid cytokines.

    Science.gov (United States)

    Warrington, Junie P

    2015-11-01

    Eclampsia is diagnosed in preeclamptic patients who develop unexplained seizures and/or coma during pregnancy or postpartum. Eclampsia is one of the leading causes of maternal and infant morbidity and mortality, accounting for ~13% of maternal deaths worldwide. Little is known about the mechanisms contributing to the pathophysiology of eclampsia, partly due to the lack of suitable animal models. This study tested the hypothesis that placental ischemia, induced by reducing utero-placental perfusion, increases susceptibility to seizures, cerebrospinal fluid (CSF) inflammation, and neurokinin B (NKB) expression in brain and plasma. Pentylenetetrazol (PTZ), a pro-convulsive drug, was injected into pregnant and placental ischemic rats (40 mg/kg, i.p.) on gestational day 19 followed by video monitoring for 30 min. Seizure scoring was blindly conducted. Placental ischemia hastened the onset of seizures compared to pregnant controls but had no effect on seizure duration. Placental ischemia increased CSF levels of IL-2, IL-17, IL-18 and eotaxin (CCL11), had no effect on plasma NKB; however, PTZ increased plasma NKB in both pregnant and placental ischemic rats. NKB was strongly correlated with latency to seizure in normal pregnant rats (R(2) = 0.88 vs. 0.02 in placental ischemic rats). Lastly, NKB decreased in the anterior cerebrum in response to placental ischemia and PTZ treatment but was unchanged in the posterior cerebrum. These data demonstrate that placental ischemia is associated with increased susceptibility to seizures and CSF inflammation; thus provides an excellent model for elucidating mechanisms of eclampsia-like symptoms. Further studies are required to determine the role of CSF cytokines/chemokines in mediating increased seizure susceptibility. PMID:26603461

  3. ASPM mutations identified in patients with primary microcephaly and seizures

    OpenAIRE

    Shen, J; Eyaid, W; Mochida, G; Al-Moayyad, F; Bodell, A; Woods, C; Walsh, C

    2005-01-01

    Background: Human autosomal recessive primary microcephaly (MCPH) is a heterogeneous disorder with at least six genetic loci (MCPH1–6), with MCPH5, caused by ASPM mutation, being the most common. Despite the high prevalence of epilepsy in microcephaly patients, microcephaly with frequent seizures has been excluded from the ascertainment of MCPH. Here, we report a pedigree with multiple affected individuals with microcephaly and seizures.

  4. Improving Sediment Transport Prediction by Assimilating Satellite Images in a Tidal Bay Model of Hong Kong

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2014-03-01

    Full Text Available Numerical models being one of the major tools for sediment dynamic studies in complex coastal waters are now benefitting from remote sensing images that are easily available for model inputs. The present study explored various methods of integrating remote sensing ocean color data into a numerical model to improve sediment transport prediction in a tide-dominated bay in Hong Kong, Deep Bay. Two sea surface sediment datasets delineated from satellite images from the Moderate Resolution Imaging Spectra-radiometer (MODIS were assimilated into a coastal ocean model of the bay for one tidal cycle. It was found that remote sensing sediment information enhanced the sediment transport model ability by validating the model results with in situ measurements. Model results showed that root mean square errors of forecast sediment both at the surface layer and the vertical layers from the model with satellite sediment assimilation are reduced by at least 36% over the model without assimilation.

  5. Hippocampal closed-loop modeling and implications for seizure stimulation design

    Science.gov (United States)

    Sandler, Roman A.; Song, Dong; Hampson, Robert E.; Deadwyler, Sam A.; Berger, Theodore W.; Marmarelis, Vasilis Z.

    2015-10-01

    Objective. Traditional hippocampal modeling has focused on the series of feedforward synapses known as the trisynaptic pathway. However, feedback connections from CA1 back to the hippocampus through the entorhinal cortex (EC) actually make the hippocampus a closed-loop system. By constructing a functional closed-loop model of the hippocampus, one may learn how both physiological and epileptic oscillations emerge and design efficient neurostimulation patterns to abate such oscillations. Approach. Point process input-output models where estimated from recorded rodent hippocampal data to describe the nonlinear dynamical transformation from CA3 → CA1, via the schaffer-collateral synapse, and CA1 → CA3 via the EC. Each Volterra-like subsystem was composed of linear dynamics (principal dynamic modes) followed by static nonlinearities. The two subsystems were then wired together to produce the full closed-loop model of the hippocampus. Main results. Closed-loop connectivity was found to be necessary for the emergence of theta resonances as seen in recorded data, thus validating the model. The model was then used to identify frequency parameters for the design of neurostimulation patterns to abate seizures. Significance. Deep-brain stimulation (DBS) is a new and promising therapy for intractable seizures. Currently, there is no efficient way to determine optimal frequency parameters for DBS, or even whether periodic or broadband stimuli are optimal. Data-based computational models have the potential to be used as a testbed for designing optimal DBS patterns for individual patients. However, in order for these models to be successful they must incorporate the complex closed-loop structure of the seizure focus. This study serves as a proof-of-concept of using such models to design efficient personalized DBS patterns for epilepsy.

  6. Variational data assimilation for a forced, inertia-free magnetohydrodynamic dynamo model

    OpenAIRE

    Li, K; A. Jackson; Livermore, P. W.

    2014-01-01

    Variational data assimilation (4DVar) is a powerful technique for tuning dynamic models to observations, in order not only to forecast future time evolution of the system, but to make inferences about quantities that are otherwise unconstrained by observation. We apply this technique, well-grounded in meteorology and oceanography, to the Earth's core where incompressible fluid motions in an electrically conducting medium are responsible for magnetic field generation. Our dynamic model's momen...

  7. Inflow and initial conditions for direct numerical simulation based on adjoint data assimilation

    OpenAIRE

    Gronskis, A; Heitz, D.; Mémin, E.

    2011-01-01

    A method for generating inflow conditions for direct numerical simulations (DNS) of spatially-developing flows is presented. The proposed method is based on variational data assimilation and adjoint-based optimization. The estimation is conducted through an iterative process involving a forward integration of a given dynamical model followed by a backward integration of an adjoint system defined by the adjoint of the discrete scheme associated to the dynamical system. The ap...

  8. Data assimilation with the ensemble Kalman filter in a numerical model of the North Sea

    Science.gov (United States)

    Ponsar, Stéphanie; Luyten, Patrick; Dulière, Valérie

    2016-07-01

    Coastal management and maritime safety strongly rely on accurate representations of the sea state. Both dynamical models and observations provide abundant pieces of information. However, none of them provides the complete picture. The assimilation of observations into models is one way to improve our knowledge of the ocean state. Its application in coastal models remains challenging because of the wide range of temporal and spatial variabilities of the processes involved. This study investigates the assimilation of temperature profiles with the ensemble Kalman filter in 3-D North Sea simulations. The model error is represented by the standard deviation of an ensemble of model states. Parameters' values for the ensemble generation are first computed from the misfit between the data and the model results without assimilation. Then, two square root algorithms are applied to assimilate the data. The impact of data assimilation on the simulated temperature is assessed. Results show that the ensemble Kalman filter is adequate for improving temperature forecasts in coastal areas, under adequate model error specification.

  9. Data assimilation with the ensemble Kalman filter in a numerical model of the North Sea

    Science.gov (United States)

    Ponsar, Stéphanie; Luyten, Patrick; Dulière, Valérie

    2016-08-01

    Coastal management and maritime safety strongly rely on accurate representations of the sea state. Both dynamical models and observations provide abundant pieces of information. However, none of them provides the complete picture. The assimilation of observations into models is one way to improve our knowledge of the ocean state. Its application in coastal models remains challenging because of the wide range of temporal and spatial variabilities of the processes involved. This study investigates the assimilation of temperature profiles with the ensemble Kalman filter in 3-D North Sea simulations. The model error is represented by the standard deviation of an ensemble of model states. Parameters' values for the ensemble generation are first computed from the misfit between the data and the model results without assimilation. Then, two square root algorithms are applied to assimilate the data. The impact of data assimilation on the simulated temperature is assessed. Results show that the ensemble Kalman filter is adequate for improving temperature forecasts in coastal areas, under adequate model error specification.

  10. Assimilation of remote sensing observations into a continuous distributed hydrological model: impacts on the hydrologic cycle

    Science.gov (United States)

    Laiolo, Paola; Gabellani, Simone; Campo, Lorenzo; Cenci, Luca; Silvestro, Francesco; Delogu, Fabio; Boni, Giorgio; Rudari, Roberto

    2015-04-01

    The reliable estimation of hydrological variables (e.g. soil moisture, evapotranspiration, surface temperature) in space and time is of fundamental importance in operational hydrology to improve the forecast of the rainfall-runoff response of catchments and, consequently, flood predictions. Nowadays remote sensing can offer a chance to provide good space-time estimates of several hydrological variables and then improve hydrological model performances especially in environments with scarce in-situ data. This work investigates the impact of the assimilation of different remote sensing products on the hydrological cycle by using a continuous physically based distributed hydrological model. Three soil moisture products derived by ASCAT (Advanced SCATterometer) are used to update the model state variables. The satellite-derived products are assimilated into the hydrological model using different assimilation techniques: a simple nudging and the Ensemble Kalman Filter. Moreover two assimilation strategies are evaluated to assess the impact of assimilating the satellite products at model spatial resolution or at the satellite scale. The experiments are carried out for three Italian catchments on multi year period. The benefits on the model predictions of discharge, LST, evapotranspiration and soil moisture dynamics are tested and discussed.

  11. Radiocarbon isotopic evidence for assimilation of atmospheric CO2 by the seagrass Zostera marina

    Directory of Open Access Journals (Sweden)

    K. Watanabe

    2015-05-01

    Full Text Available Submerged aquatic vegetation assimilates dissolved inorganic carbon (DIC in the water column as a carbon source across its thin cuticle layer. However, it is expected that marine macrophytes also use atmospheric CO2 when exposed to the air during low tide, although assimilation of atmospheric CO2 has never been quantitatively evaluated. Using the radiocarbon isotopic signatures (Δ14C of the seagrass Zostera marina and DIC, we show quantitatively that Z. marina takes up and assimilates atmospheric modern CO2 in a shallow coastal ecosystem. The Δ14C values of the seagrass (−36 to −8‰ were significantly higher than those of aquatic DIC (−45 to −18‰, indicating that the seagrass uses a 14C-rich carbon source (atmospheric CO2, +17‰. A carbon-source mixing model indicated that the seagrass assimilated ~ 46% (mean: 22% of its inorganic carbon as atmospheric CO2. CO2 exchange between the air and the seagrass may be enhanced by the presence of a very thin water film over the air-exposed leaves during low tide. Our radiocarbon isotope analysis, showing assimilation of atmospheric modern CO2 as an inorganic carbon source, offers better understanding of the role of seagrass meadows in coastal carbon dynamics.

  12. INTERMITTENT CLONAZEPAM IN THE PREVENTION OF RECURRENT FEBRILE SEIZURES

    Directory of Open Access Journals (Sweden)

    BAJOGHLI Shirin MD

    2010-09-01

    Full Text Available ObjectiveTo evaluate the efficacy and common side effects of intermittent clonazepamin febrile seizures.Materials & MethodsThis study was an experimental trial designed to determine the efficacy ofintermittent clonazepam in febrile seizures .Thirty patients with an age rangeof 6 months to 5 years (60% male, 40% female were studied. Children with ahistory of psychomotor delay, abnormal neurological examination, a history ofantiepileptic drug consumption, and afebrile seizures were excluded from thestudy. Patients received a single dose of prophylactic Clonazepam (0.05 mg/kg/day on the first day of febrile illness and twice daily during the course of fever.An antipyretic medication (Acetaminophen was advised if fever exceeded38oC. Patients were followed up for one year after the study inclusion date.ResultsThree patients were excluded from study since they didnot follow the tritmentand three patients experienced afebrile seizures. Twenty four patients had 162febrile episodes during the course of the study and all patients were seizure-freeafter 1 year.ConclusionClonazepam was 100% effective but lethargy and ataxia were common sideeffects in patients. Fortunately, their parents continued treatment because theyhad prior awareness of the possible side effects of clonazepam. Clonazepam isefficacious as an intermittent therapy for febrile seizures if parents are informedof its side effects.

  13. A physiology-based seizure detection system for multichannel EEG.

    Directory of Open Access Journals (Sweden)

    Chia-Ping Shen

    Full Text Available BACKGROUND: Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures. Electroencephalogram (EEG signals play a critical role in the diagnosis of epilepsy. Multichannel EEGs contain more information than do single-channel EEGs. Automatic detection algorithms for spikes or seizures have traditionally been implemented on single-channel EEG, and algorithms for multichannel EEG are unavailable. METHODOLOGY: This study proposes a physiology-based detection system for epileptic seizures that uses multichannel EEG signals. The proposed technique was tested on two EEG data sets acquired from 18 patients. Both unipolar and bipolar EEG signals were analyzed. We employed sample entropy (SampEn, statistical values, and concepts used in clinical neurophysiology (e.g., phase reversals and potential fields of a bipolar EEG to extract the features. We further tested the performance of a genetic algorithm cascaded with a support vector machine and post-classification spike matching. PRINCIPAL FINDINGS: We obtained 86.69% spike detection and 99.77% seizure detection for Data Set I. The detection system was further validated using the model trained by Data Set I on Data Set II. The system again showed high performance, with 91.18% detection of spikes and 99.22% seizure detection. CONCLUSION: We report a de novo EEG classification system for seizure and spike detection on multichannel EEG that includes physiology-based knowledge to enhance the performance of this type of system.

  14. School involvement in the treatment of seizure disorders.

    Science.gov (United States)

    Gadow, K D

    1982-04-01

    In has long been recognized that school personnel can play an important role in the treatment of seizure disorders. In order to better understand their involvement in the treatment process, two state-wide studies of special education programs were conducted. Teachers completed questionnaires for 315 pupils in their classrooms who were receiving drug therapy for a seizure disorder, and the mothers of 130 of these children were interviewed by telephone. The two investigations yielded similar results. Teachers were often not informed about the overt features of the seizures, side effects of the medication, or seizure management, even in the case of students who experienced seizures and/or side effects in school. In 70% of the cases, teachers were involved in either evaluating the response to treatment, administering medication, or managing (coping with) seizures in the classroom. They usually interacted with parents or other school personnel; direct communication with the physician was virtually nonexistent. Over one-third of the students were rated as more drowsy or sleepy than their peers, and, according to teachers, drug-induced impairments in adaptive behavior were a common problem. Collectively, these data suggest that in many cases, no one has assumed responsibility for coordinating the delivery of services for psychosocial treatment needs. PMID:7075574

  15. Long-term effects of febrile convulsion on seizure susceptibility in P77PMC rat--resistant to acoustic stimuli but susceptible to kainate-induced seizures.

    Science.gov (United States)

    Zhao, D Y; Wu, X R; Pei, Y Q; Zuo, Q H

    1985-06-01

    A new audiogenic seizure (AGS)-susceptible strain of rats (P77PMC) was evaluated as a possible model of human febrile seizures. The long-term effects of experimental febrile seizures were observed. All 30-day-old rat pups exhibited clonic seizures during exposure to an ambient temperature of 45 +/- 0.5 degree C. The mean latency from the beginning of the hyperthermic stimulus to the onset of convulsion was 16.9 +/- 2.2 min. The rats survived this hyperthermic seizure, developed a resistance to acoustic stimulations, but were more susceptible at the age of 50 to 60 days to kainate-induced limbic seizures than controls. The results of this study imply that febrile seizures of developing P77PMC rats can change later seizure susceptibility, and there may be some correlation between febrile convulsion and temporal lobe epilepsy. PMID:3996515

  16. Dark Matter Assimilation into the Baryon Asymmetry

    CERN Document Server

    D'Eramo, Francesco; Thaler, Jesse

    2011-01-01

    Pure singlets are typically disfavored as dark matter candidates, since they generically have a thermal relic abundance larger than the observed value. In this paper, we propose a new dark matter mechanism called "assimilation", which takes advantage of the baryon asymmetry of the universe to generate the correct relic abundance of singlet dark matter. Through assimilation, dark matter itself is efficiently destroyed, but dark matter number is stored in new quasi-stable heavy states which carry the baryon asymmetry. The subsequent annihilation and late-time decay of these heavy states yields (symmetric) dark matter as well as (asymmetric) standard model baryons. We study in detail the case of pure bino dark matter by augmenting the minimal supersymmetric standard model with vector-like chiral multiplets. In the parameter range where this mechanism is effective, the LHC can discover long-lived charged particles which were responsible for assimilating dark matter.

  17. Effect of electroconvulsive seizures on pattern separation.

    Science.gov (United States)

    Svensson, Maria; Grahm, Matilda; Ekstrand, Joakim; Movahed-Rad, Pouya; Johansson, Mikael; Tingström, Anders

    2015-11-01

    Strategies employing different techniques to inhibit or stimulate neurogenesis have implicated a role for adult-born neurons in the therapeutic effect of antidepressant drugs, as well as a role in memory formation. Electroconvulsive seizures (ECS), an animal model of electroconvulsive therapy, robustly stimulate hippocampal neurogenesis, but it is not known how this relates to either therapeutic efficacy or unwanted cognitive side effects. We hypothesized that the ECS-derived increase in adult-born neurons would manifest in improved pattern separation ability, a memory function that is believed to be both hippocampus-dependent and coupled to neurogenesis. To test this hypothesis, we stimulated neurogenesis in adult rats by treating them with a series of ECS and compared their performances in a trial-unique delayed nonmatching-to-location task (TUNL) to a control group. TUNL performance was analyzed over a 12-week period, during which newly formed neurons differentiate and become functionally integrated in the hippocampal neurocircuitry. Task difficulty was manipulated by modifying the delay between sample and choice, and by varying the spatial similarity between target and distracter location. Although animals learned the task and improved the number of correct responses over time, ECS did not influence spatial pattern separation ability. PMID:25850383

  18. Correction of deposition predictions with data assimilation

    International Nuclear Information System (INIS)

    Model predictions for rapid assessment and prognosis of possible radiological consequences after an accidental release of radionuclides play an important role in nuclear emergency management. Radiological measurements (e. g., dose rate measurements) can be used to improve such model predictions. This paper describes a method for combining model predictions and measurements (data assimilation) in the deposition model of the European radiological decision support system RODOS. The data assimilation approach is based on the Ensemble Kalman Filter, a Monte Carlo variant of the Kalman filter. (orig.)

  19. Increased Seizure Latency and Decreased Severity of Pentylenetetrazol-Induced Seizures in Mice after Essential Oil Administration

    OpenAIRE

    Eleni Koutroumanidou; Athanasios Kimbaris; Alexandros Kortsaris; Eugenia Bezirtzoglou; Moschos Polissiou; Konstantinos Charalabopoulos; Olga Pagonopoulou

    2013-01-01

    The effect of pretreatment with essential oils (EOs) from eight aromatic plants on the seizure latency and severity of pentylenetetrazol- (PTZ-) induced seizures in mice was evaluated. Weight-dependent doses of Rosmarinus officinalis, Ocimum basilicum, Mentha spicata, Mentha pulegium, Lavandula angustifolia, Mentha piperita, Origanum dictamnus, and Origanum vulgare, isolated from the respective aromatic plants from NE Greece, were administered 60 minutes prior to intraperitoneal (i.p.) inject...

  20. ANALYSIS OF MAIN REASONS FOR MISTAKES IN DIAGNOSTICS OF EPILEPTIC SEIZURES AND EPILEPTIC SYNDROMES (CLINICAL PECULIARITIES OF EPILEPTIC SEIZURES

    Directory of Open Access Journals (Sweden)

    M. B. Mironov

    2015-04-01

    Full Text Available Epilepsy is a chronic brain disease that requires long therapy and continuous careful supervision of the status of the patient. In connection with this, both overdiagnosis and underdiagnosis of this disease is extremely dangerous. Overdiagnosis causes ungrounded social "label", limitation in rights, significant decreasing quality of life of the patient, family problems, prescription of long-term anti-epileptic therapy that may cause potential side effects. Underdiagnosis of epilepsy frequently causes further resistance of seizures to therapy, they become more frequent, there appears the possibility of development of epileptic status, life threatening situations, possibility of development of cognitive disorders associated with the disease. A significant progress in epileptology and medical technologies (video electroencephalographic (EEG monitoring, neuroimaging methods, genetic studies that has been marked in recent decades has allowed minimizing errors of physicians. Despite this, certain difficulties still remain in diagnostics of epilepsy. In the author's opinion, there is a range of epileptic seizures visual assessment of which is extremely difficult and is literally impossible without video EEG monitoring. Short, phantom, atypical absences, absences on the outside, epileptic myoclonus of the eyelids with or without absences, myoclonic, tonic, gelastic, focal hyperkinetic seizures, epileptic aura, reversing focal seizures, epileptic spasms, ictal syncopes, negative myoclonus, focal epileptic myoclonus, epileptic seizures arising when closing the eyes, and self-induced seizures can be attributed to such seizures with difficulties in diagnosis. The author reviews each of these types epileptic seizures in details focusing the attention on their diagnostic criteria and characteristics of the clinical and the EEF features that are of utmost importance in the course of performance of differential diagnostics. Own experience of the

  1. Predictive factors of seizure control in childhood onset epilepsy

    Directory of Open Access Journals (Sweden)

    Eli Shahar

    2008-01-01

    Full Text Available Background: Prediction of the long-term outcomes of childhood-onset epilepsy remains crucial for the future well-being of the affected children and their families and for planning proper therapeutic and educational programs. Objective: To identify and analyze the early predictive factors of seizure control in childhood-onset epilepsies referred at the age of 1 month up to the age of 18 years to the Epilepsy Service at the Meyer Children Hospital, Rambam Medical Center, Haifa, Israel. Materials and Methods: In this study, children who were newly diagnosed with epileptic disorders and treated with antiepileptic drug therapy - who became either completely controlled for at least twelve months or those remaining intractable - were included. Partially responding children were excluded from the analysis. The etiology was segregated into either symptomatic or nonsymptomatic epilepsy, referred to as idiopathic epilepsy. Results: Overall, 74 children (mean age: 4.27 ± 4 years at the first seizure were found eligible for analysis followed for a mean period of 4.5 years. Fifty-three (72% children became seizure-free for a mean period of 20 months on antiepileptic drug (AED therapy and 21 (28% remained uncontrolled. Sixty out of 74 children (81% had idiopathic epilepsy and 14 (19% had symptomatic epilepsy. In those with idiopathic epilepsy, 46 (77% children gained complete seizure control in comparison to 7 out of 14 (50% children in the symptomatic group ( P < 0.01. Thirty-nine out of 47 (83% children who had normal cognition became seizure-free, and 14 (52% out of 27 mentally retarded children also became seizure-free ( P < 0.01. The outcome of seizure control was not affected by age at onset and seizure type itself during the presentation. Conclusion: The present study reveals that the single most predictive factor of a favorable seizure control is preserved cognitive function in accordance with idiopathic epilepsy. However, a fairly high number of

  2. Differentiation between Trichophyton mentagrophytes and T. rubrum by sorbitol assimilation.

    OpenAIRE

    Rezusta, A; Rubio, M C; Alejandre, M C

    1991-01-01

    Trichophyton rubrum was easily differentiated from T. mentagrophytes by its ability to assimilate sorbitol with an API 20C AUX strip. One hundred percent of 36 T. rubrum strains and none of 147 T. mentagrophytes strains assimilated sorbitol.

  3. Zinc Status in Febrile Seizure: A Case-Control Study

    Directory of Open Access Journals (Sweden)

    MohammadReza SALEHIOMRAN

    2013-11-01

    Full Text Available How to Cite This Article: Salehiomran MR, Mahzari M. Zinc Status in Febrile Seizure: A Case-Control Study. Iran J Child Neurol. 2013 Autumn; 7(4:20-23.ObjectiveFebrile seizure is the most common type of seizure in children. Their incidence is 2-5%. There are different hypotheses about relationship between neurotransmitters and trace elements (such as zinc and febrile seizure. Zinc, asa major element of some enzymes, plays an important role in the central nervous system (CNS and can affect some inhibitory mechanisms of CNS. The aim of the present study was to determine whether there were any changes in serumzinc level in children with febrile seizure in comparison with febrile children without seizure.Materials & MethodsThis case-control study was performed on 100 patients aged 6 months to 6 years.This study was conducted between January and August 2012, on 50 children with febrile seizures (case and 50 febrile children without seizures (control, that were referred to Amirkola Children Hospital (a referral hospital in the northof Iran. Two groups were matched for age and sex. The serum zinc levels in the both groups were determined by atomic absorption spectrophotometry method.ResultsThe mean serum zinc level was 0.585±0.166 mg/L and 0.704±0.179 mg/L in the case group and the control group, respectively (p=0.001. The mean serum zinc level was significantly lower in the febrile seizure group compared to thecontrol groups.  ConclusionOur findings revealed that serum zinc level was significantly lower in children with simple febrile seizure in comparison with febrile children without seizure. It can emphasize the hypothesis that there is a relation between serum zinc level and febrile seizure in children. ReferencesVarma RR. Febrile seizures. Indian J Pediatr 2002; 69(8; 697-700.Talebian A, Vakili Z, Talar SA, Kazemi M, Mousavi GA. Assessment of the relation between serum zinc and magnesium levels in children with febrile

  4. Economic and Cultural Assimilation and Integration of Immigration in Europe

    OpenAIRE

    Mariya Aleksynska; Yann Algan

    2010-01-01

    This paper documents assimilation of immigrants in 16 European countries along cultural, civic, and economic dimensions, distinguishing by immigrants’ generation, duration of stay, and origin. It suggests that assimilation may have multiple facets, and take place at different speed depending on the outcome in question. While assimilation along some economic outcomes may be correlated with assimilation along some cultural outcomes, such correlations are not systematic, and imply that progress ...

  5. Assimilation violation and spoken-language processing: A supplementary report

    OpenAIRE

    Weber, A

    2002-01-01

    Previous studies have shown that spoken-language processing is inhibited by violation of obligatory regressive assimilation. Weber (2001) replicated this inhibitory effect in a phoneme-monitoring study examining regressive place assimilation of nasals, but found facilitation for violation of progressive assimilation. German listeners detected the velar fricative [x] more quickly when fricative assimilation was violated (e.g., *[bIxt] or *[blInx@n]) than when no violation occurred (e.g., [baxt...

  6. ASSIMILATION SYSTEM AT DHMZ: DEVELOPMENT AND FIRST VERIFICATION RESULTS

    OpenAIRE

    Stanešić, Antonio

    2011-01-01

    Abstract: In this paper, a description of the setup for a local assimilation system for a limited area model, ALADIN (Aire Limiteé Adaptation Dynamique dévelopement InterNational), is given with a comprehensive description of the assimilation techniques used. The assimilation system at DHMZ (Meteorological and Hydrological Service of Croatia) consisted of two parts: the surface assimilation, which was used to change the state of a model land surface variables, and the upper air assimilatio...

  7. The Long-term Risk of Epilepsy after Febrile Seizures in susceptible subgroups

    DEFF Research Database (Denmark)

    Vestergaard, Mogens; Pedersen, Carsten Bøcker; Sidenius, Per Christian; Olsen, Jørn; Christensen, Jakob

    2007-01-01

    A family history of seizures, preexisting brain damage, or birth complications may modify the long-term risk of epilepsy after febrile seizures. The authors evaluated the association between febrile seizures and epilepsy in a population-based cohort of 1.54 million persons born in Denmark (1978......-2002), including 49,857 persons with febrile seizures and 16,481 persons with epilepsy. Overall, for children with febrile seizures compared with those without such seizures, the rate ratio for epilepsy was 5.43 (95% confidence interval: 5.19, 5.69). The risk remained high during the entire follow-up but was...... particularly high shortly after the first febrile seizure, especially in children who experienced early (<1 year of age) or late (>3 years of age) onset of febrile seizures. At 23 years of follow-up, the overall cumulative incidence of epilepsy after febrile seizures was 6.9% (95% confidence interval: 6.5, 7...

  8. Patterns of muscle activation during generalized tonic and tonic–clonic epileptic seizures

    DEFF Research Database (Denmark)

    Conradsen, Isa; Wolf, Peter; Sams, Thomas; Sørensen, Helge Bjarup Dissing; Beniczky, Sándor

    2011-01-01

    Purpose: Tonic seizures and the tonic phase of tonic–clonic epileptic seizures are defined as “sustained tonic” muscle contraction lasting a few seconds to minutes. Visual inspection of the surface electromyogram (EMG) during seizures contributed considerably to a better understanding and accurate...... diagnosis of several seizure types. However, quantitative analysis of the surface EMG during the epileptic seizures has received surprisingly little attention until now. The aim of our study was to elucidate the pathomechanism of the tonic muscle activation during epileptic seizures. Methods: Surface EMG...... was recorded from the deltoid muscles, on both sides, during 63 seizures from 20 patients with epilepsy (10 with generalized tonic and 10 with tonic–clonic seizures). Twenty age‐ and gender‐matched normal controls simulated 100 generalized tonic seizures. To characterize the signal properties we...

  9. Thalamus lesions in chronic and acute seizure disorders

    Energy Technology Data Exchange (ETDEWEB)

    Tschampa, Henriette J.; Greschus, Susanne; Urbach, Horst [University of Bonn, Department of Radiology (Neuroradiology), Bonn (Germany); Sassen, Robert; Bien, Christian G. [University of Bonn, Department of Epileptology, Bonn (Germany)

    2011-04-15

    Transient signal changes in the pulvinar have been described following status epilepticus. However, we observed persistent thalamus changes after seizures. The purpose of this study was to characterize thalamus changes in patients with seizure disorders and to correlate imaging findings with clinical features. We searched among 5,500 magnetic resonance imaging (MRI) exams performed in patients with seizures and identified 43 patients. The MRI scans of these patients were reviewed and correlated with clinical data. We identified four patterns of thalamus lesions: (a) fluid attenuated inversion recovery-hyperintense pulvinar lesions (20 patients), as known from status epilepticus. Ten patients in this group had a status epilepticus. Among the remaining patients, three had frequent seizures and seven had sporadic seizures. Twelve patients had follow-up exams for a median of 11 months. The lesions had persisted in 11/12 cases in the last available exam and were reversible in one case only. In seven cases, cone-shaped thalamus atrophy resulted, (b) linear defects in the medial and anterior thalamus (five patients), accompanied by atrophy of the mamillary body and the fornix in patients with chronic epilepsy, (c) extensive bilateral thalamus lesions in two patients with a syndrome caused by mutation in the mitochondrial polymerase gamma, and (d) other thalamus lesions not associated with the seizure disorder (16 patients). The spectrum of thalamus lesions in patients with seizure disorders is wider than previously reported. Postictal pulvinar lesions can persist and may result in thalamic atrophy. Linear defects in the anterior thalamus are associated with limbic system atrophy. (orig.)

  10. Thalamus lesions in chronic and acute seizure disorders

    International Nuclear Information System (INIS)

    Transient signal changes in the pulvinar have been described following status epilepticus. However, we observed persistent thalamus changes after seizures. The purpose of this study was to characterize thalamus changes in patients with seizure disorders and to correlate imaging findings with clinical features. We searched among 5,500 magnetic resonance imaging (MRI) exams performed in patients with seizures and identified 43 patients. The MRI scans of these patients were reviewed and correlated with clinical data. We identified four patterns of thalamus lesions: (a) fluid attenuated inversion recovery-hyperintense pulvinar lesions (20 patients), as known from status epilepticus. Ten patients in this group had a status epilepticus. Among the remaining patients, three had frequent seizures and seven had sporadic seizures. Twelve patients had follow-up exams for a median of 11 months. The lesions had persisted in 11/12 cases in the last available exam and were reversible in one case only. In seven cases, cone-shaped thalamus atrophy resulted, (b) linear defects in the medial and anterior thalamus (five patients), accompanied by atrophy of the mamillary body and the fornix in patients with chronic epilepsy, (c) extensive bilateral thalamus lesions in two patients with a syndrome caused by mutation in the mitochondrial polymerase gamma, and (d) other thalamus lesions not associated with the seizure disorder (16 patients). The spectrum of thalamus lesions in patients with seizure disorders is wider than previously reported. Postictal pulvinar lesions can persist and may result in thalamic atrophy. Linear defects in the anterior thalamus are associated with limbic system atrophy. (orig.)

  11. Eslicarbazepine Acetate Monotherapy: A Review in Partial-Onset Seizures.

    Science.gov (United States)

    Shirley, Matt; Dhillon, Sohita

    2016-04-01

    Eslicarbazepine acetate (Aptiom(®)) is a once-daily, orally administered antiepileptic drug (AED) approved previously in the EU, USA and several other countries for use as adjunctive therapy for the treatment of partial-onset seizures. Based on the findings of two randomized, dose-blinded, conversion-to-monotherapy phase III trials in patients with uncontrolled partial epilepsy, the US license for eslicarbazepine acetate has recently been expanded to include use as monotherapy for partial-onset seizures. The pivotal trials demonstrated that seizure control following conversion from other AEDs was superior for eslicarbazepine acetate monotherapy (1200 or 1600 mg once daily) compared with a pseudo-placebo historical control. Other efficacy outcomes appeared to support the benefit of treatment, with up to 10 % of patients remaining seizure free and up to 46 % of patients experiencing a ≥50 % reduction from baseline in standardized seizure frequency during the monotherapy periods of the trials. Eslicarbazepine acetate monotherapy was generally well tolerated, with most treatment-emergent adverse events being mild to moderate in severity. Its tolerability profile was generally consistent with the established profile of the drug based on its use as adjunctive therapy. Thus, once-daily eslicarbazepine acetate, either as monotherapy or adjunctive therapy, represents a useful option for the treatment of patients with partial-onset seizures. The recent licensing of the drug in the USA as monotherapy expands the range of treatment options for patients with partial-onset seizures and increases the opportunity to tailor therapy to the individual patient. PMID:27055527

  12. Communicating the diagnosis of psychogenic nonepileptic seizures: The patient perspective.

    Science.gov (United States)

    Arain, Amir; Tammaa, Maamoon; Chaudhary, Faria; Gill, Shazil; Yousuf, Syed; Bangalore-Vittal, Nandakumar; Singh, Pradumna; Jabeen, Shagufta; Ali, Shahid; Song, Yanna; Azar, Nabil J

    2016-06-01

    Psychogenic nonepileptic seizures (PNES) are a common cause of refractory seizures. Video-electroencephalographic (EEG) monitoring has allowed PNES to be effectively distinguished from epileptic seizures. Once the diagnosis of PNES is established, neurologists face the challenge of explaining it to patients. Patients may not always receive the diagnosis well. The aim of this study is to evaluate how effectively patients receive and perceive the diagnosis of PNES. This prospective study was conducted in an eight-bed epilepsy monitoring unit (EMU). Adult patients with newly confirmed PNES were included. After receiving written consent, a self-administered questionnaire was given to patients after the attending physician had communicated the diagnosis of PNES. A total of 75 patients were recruited. All patients had their typical seizures recorded on video-EEG (range 1-12, mean 2.18). Seventy patients were satisfied with the diagnosis of PNES. Nine patients did not agree that PNES has a psychological cause. Nineteen patients thought that the EMU doctors had no clue as to the cause of their seizures and 20 thought that there was no hope for a cure of their seizures. A significant number of patients with PNES feel that there is no hope for cure of their seizures. Thorough education about PNES, properly preparing patients before discussing the diagnosis of PNES, and preferably earlier diagnosis may prevent this miscommunication and result in better outcomes. A comprehensive approach including psychological counseling and psychiatric input, evaluation and treatment, in order to bring the illness from the subconscious to the conscious level, and effective follow-up may be helpful. PMID:26860851

  13. Descriptions of clinical semiology of seizures in literature.

    Science.gov (United States)

    Wolf, Peter

    2006-03-01

    Literary texts are an important part of the cultural history of many fields of medicine. Accounts of epilepsy are frequent, and descriptions of seizure semiology are often included with varying detail. This review looks at these, and considers the authors' background knowledge of epilepsy. The first group of writers suffered seizures themselves. Some of them provide remarkable and novel insights into the subjective symptoms and experiences in and around seizures.A second group draws from their own observations of seizures in others who may have been close relatives or fortuitous strangers. Here, the outside view prevails, and seizures may be described with clinical objectiveness. Commonly, the reactions of onlookers become part of the narrative beyond the seizure description. The third group writes from second-hand knowledge, which may be other observer reports, interviews with people with epilepsy or with experts, information being available in dictionaries, medical textbooks and the like. The professional standard of most writers means that the resulting descriptions are quite accurate, but there are also examples of poor use of such information. Many authors' sources are not known, but can be assumed to belong to one of the above categories, and we can sometimes guess. It appears that even authors with no first-hand knowledge are often aware of seizure types other than the most widely known, generalised tonic-clonic, and there is a widespread interest in warnings and how the afflicted respond to them. The quality of an author's fictional account of epilepsy should not be judged from a translation, because specific aspects and the language involved in the description may have been misunderstood by the translator. PMID:16567320

  14. Data assimilation for computing model evidence: The attribution problem

    Science.gov (United States)

    Carrassi, Alberto; Bocquet, Marc; Hannart, Alexis; Ghil, Michael

    2016-04-01

    A new approach potentially useful for near real time, systematic causal attribution of weather and climate-related events is described. The method is purposely designed to allow its operability at meteorological centers by synergizing causal attribution with Data Assimilation (DA) methods usually designed to deal with large nonlinear models. The concept of contextual model evidence is introduced and its link with causal attribution is stressed. It is then shown how contextual model evidence can be obtained as a side-product of the statistical inference performed for the assimilation of data. Three strategies are considered: DA-based ensemble forecasting, filtering and smoothing. The theoretical rationale of this approach is explained along with the advantages, drawbacks and limits of applicability of each strategy depending on the degree of instabilities of the underlying dynamics. The prominent features of a DA-based detection and attribution procedure are discussed. The proposal is illustrated numerically with low-order nonlinear models, and is compared with standard methods for detection and attribution showing promising performance. The convergence of the different DA-based estimates of the model evidence toward the unknown true value is explored numerically in some specific case. The method stresses on the concept of model evidence, and open questions on how to compute and interpret the response to forcing whose effects one wants to contrast with respect to model error and other source of uncertainties. Practical obstacles that need to be addressed to make the proposal readily operational within weather forecasting centers are finally laid out.

  15. Data ingestion and assimilation in ionospheric models

    Czech Academy of Sciences Publication Activity Database

    Burešová, Dalia; Nava, B.; Galkin, I.; Angling, M.; Stankov, S. M.; Coisson, P.

    2009-01-01

    Roč. 52, 3/4 (2009), s. 235-253. ISSN 1593-5213 R&D Projects: GA ČR GA205/08/1356; GA MŠk OC 091 Institutional research plan: CEZ:AV0Z30420517 Keywords : ionosphere * models * data assimilation * data ingestion Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.548, year: 2009

  16. The Silent Minority: Assimilated or Marginal?

    Science.gov (United States)

    Howell, Gladys David

    In this paper, the concept of "invisible ethnic" is used to refer to an individual who is identified as different by dominant members of society and who is caught between an ancestral identity and culture on the one hand, and a wish to be assimilated, on the other. This concept is discussed in relation to Stonequist's "marginal man" and the social…

  17. A new sequential data assimilation method

    Institute of Scientific and Technical Information of China (English)

    HAN YueQi; ZHANG YaoCun; WANG YunFeng; YE Song; FANG HanXian

    2009-01-01

    A new sequential data assimilation method named "Monte Carlo H∞ filter" is Introduced based on H∞ filter technique and Monte Carlo method in this paper. This method applies to nonlinear systems in condition of lacking the statistical properties of observational errors. In order to compare the assimilation capability of Monte Carlo H= filter with that of the ensemble Kalman filter (EnKF) in solving practical problems caused by temporal correlation or spatial correlation of observational errors, two numerical experiments are performed by using Lorenz (1963) system and shallow-water equations respectively. The result is that the assimilation capability of the new method is better than that of EnKF method. It is also shown that Monte Carlo H∞ filter assimilation method is effective and suitable to nonlinear systems in that it does not depend on the statistical properties of observational errors and has better robustnesa than EnKF method when the statistical properties of observational errors are varying. In addition, for the new method, the smallest level factor founded by search method is flow-dependent.

  18. Approach To The First Unprovoked Seizure- PART I

    Directory of Open Access Journals (Sweden)

    Mohammad GHOFRANI

    2013-08-01

    Full Text Available How to Cite This Article: Ghofrani M. Approach To The First Unprovoked Seizure- PART I. Iran J Child Neurol. 2013 Summer; 7(3: 1- 5. The approach to a child who has experienced a first unprovoked generalized tonic-clonic seizure is challenging and at the same time controversial.How to establish the diagnosis, ways and means of investigation and whether treatment is appropriate, are different aspects of this subject.In this writing the above mentioned matters are discussed.References1. Bluvstein JS, Moshe SL. First unprovoked seizure CurrentManagement in child Neurology, third ed. 2005.P.89-92.2. Hirtz D, Berg A, Bettis D, et al. Practice Parameter: treatment of the child with a first unprovoked seizure. American Academy of Neurology 2003;60:166-175.3. Verity GM, Ross EN, Golding J. Epilepsy in the first ten years of life: finding of the child health and education study. Br Med J 1992;305:857-861.4. Camfiled CS, Camfield PB, Gordon K, et al. Incidence of epilepsy in childhood and adolescence: A populationbasedstudy in Nova Scotia from 1977 to 1985. Epilepsia 1996;37:19-23.5. Hauser W, Annegers J, Kurland L. Incidence of epilepsy and unprovoked seizure in Rochester, Minnisota, 1935- 1984. Epilepsia 1993;34:453-468.6. Jallon P, Goumaz M, Haenggeli G, Morabia A. Incidenceof first epileptic seizure in the canton of Geneve Switzerland. Epilepsia 1997;38:547-552.7. Camfiled PR, Camfiled CS. Pediatric Epilepsy: An overview. Swaiman’s pediatric Neurology, 5th ed, 2012. P.703-710.8. Gowers WB. Epilepsy and other chronic convulsive diseases; their causes, symptoms and treatment. London: J&A Churchill,1881. P.242.9. Goddard GV, Mc Intyre DC, Leech CK. A permanent change in brain function resulting from daily electrical stimulation- Exp Neural 1969;25:295-330.10. Berg AT, Shinnar S. Do seizures beget seizure? An assessment of the clinical evidence in human. J ClinicalNeurophysiol 1993: 14: 102-110.11. Wasterlain CG. Recurrent seizures in developing brain

  19. Strengths and Limitations of Data Assimilation Models

    Science.gov (United States)

    Schunk, R. W.; Scherliess, L.; Sojka, J. J.; Thompson, D. C.; Zhu, L.

    2006-12-01

    As part of the Global Assimilation of Ionospheric Measurements (USU-GAIM) program, we developed two Kalman filter data assimilation models of the global ionosphere, including Gauss-Markov (GM) and Full Physics (FP) models. Our Gauss-Markov model uses a physics-based ionospheric model and a Kalman filter as a basis for assimilating the measurements. The physics-based model is the Ionosphere Forecast Model (IFM), which is a multi-ion global model that covers the E-region, F-region, and topside from 90 to 1400 km. The GM model has both regional and global capabilities and the output of the model is a 3-dimensional Ne distribution at specified times. With the GM model the ionospheric densities obtained from the IFM constitute a background ionospheric density field on which perturbations are superimposed based on the available data sources and their errors. The density perturbations and the associated errors evolve over time via a statistical Gauss-Markov process. Our full physics data assimilation model is more sophisticated than the Gauss-Markov model. This model is based on a physics-based ionosphere-plasmasphere-polar wind model, which includes six ion species (NO+, O2+, N2+, O+, H+, and He+) and covers the low-mid latitudes from 90 to 20,000 km. In addition to the global Ne distribution, the full physics model also provides global distributions of the self-consistent drivers (neutral winds and composition, electric fields, and particle precipitation). Both models can assimilate in situ electron densities from 4 DMSP satellites, bottomside Ne profiles from 30 ionosondes, slant TECs from up to 1000 ground GPS/TEC receivers, occultation data and line-of-sight UV emissions. The USU-GAIM models are now being widely used, but as with all physics-based data assimilation models, care must be exercised because these models have both strengths and limitations. Some of the important issues relate to the quality, amount and distribution of the data, the ability to obtain

  20. Estimation of friction parameters in gravity currents by data assimilation in a model hierarchy

    Directory of Open Access Journals (Sweden)

    A. Wirth

    2011-01-01

    Full Text Available This paper is the last in a series of three investigating the friction laws and their parametrisation in idealised gravity currents in a rotating frame. Results on the dynamics of a gravity current (Wirth, 2009 and on the estimation of friction laws by data assimilation (Wirth and Verron, 2008 are combined to estimate the friction parameters and discriminate between friction laws in non-hydrostatic numerical simulations of gravity current dynamics, using data assimilation and a reduced gravity shallow water model.

    I demonstrate, that friction parameters and laws in gravity currents can be estimated using data assimilation. The results clearly show that friction follows a linear Rayleigh law for small Reynolds numbers and the estimated value agrees well with the analytical value obtained for non-accelerating Ekman layers. A significant and sudden departure towards a quadratic drag law at an Ekman layer based Reynolds number of around 800 is shown, in agreement with classical laboratory experiments. The drag coefficient obtained compare well to friction values over smooth surfaces. I show that data assimilation can be used to determine friction parameters and discriminate between friction laws and that it is a powerful tool in systematically connection models within a model hierarchy.

  1. Estimation of friction parameters in gravity currents by data assimilation in a model hierarchy

    Directory of Open Access Journals (Sweden)

    A. Wirth

    2011-04-01

    Full Text Available This paper is the last in a series of three investigating the friction laws and their parametrisation in idealised gravity currents in a rotating frame. Results on the dynamics of a gravity current (Wirth, 2009 and on the estimation of friction laws by data assimilation (Wirth and Verron, 2008 are combined to estimate the friction parameters and discriminate between friction laws in non-hydrostatic numerical simulations of gravity current dynamics, using data assimilation and a reduced gravity shallow water model.

    I demonstrate, that friction parameters and laws in gravity currents can be estimated using data assimilation. The results clearly show that friction follows a linear Rayleigh law for small Reynolds numbers and the estimated value agrees well with the analytical value obtained for non-accelerating Ekman layers. A significant and sudden departure towards a quadratic drag law at an Ekman layer based Reynolds number of around 800 is shown, in agreement with classical laboratory experiments. The drag coefficient obtained compares well to friction values over smooth surfaces. I show that data assimilation can be used to determine friction parameters and discriminate between friction laws and that it is a powerful tool in systematically connecting models within a model hierarchy.

  2. Assimilative and non-assimilative color spreading in the watercolor configuration

    OpenAIRE

    Eiji eKimura; Mikako eKuroki

    2014-01-01

    A colored line flanking a darker contour will appear to spread its color onto an area enclosed by the line (watercolor effect). The watercolor effect has been characterized as an assimilative effect, but non-assimilative color spreading has also been demonstrated in the same spatial configuration; e.g., when a black inner contour (IC) is paired with a blue outer contour (OC), yellow color spreading can be observed. To elucidate visual mechanisms underlying these different color spreading effe...

  3. The Parallel Data Assimilation Framework PDAF - a flexible software framework for ensemble data assimilation

    OpenAIRE

    Nerger, Lars; Hiller, Wolfgang; Schröter, Jens

    2012-01-01

    Ensemble filter algorithms can be implemented in a generic way such that they can be applied with various models with only a minimum amount of recoding. This is possible due to the fact that ensemble filters can operate on abstract state vectors and require only limited information about the numerical model and the observational data used for a data assimilation application. To build an assimilation system, the analysis step of a filter algorithm needs to be connected to t...

  4. Montelukast reduces seizures in pentylenetetrazol-kindled mice

    Directory of Open Access Journals (Sweden)

    J. Fleck

    2016-01-01

    Full Text Available Cysteinyl leukotrienes (CysLTs have been implicated in seizures and kindling; however, the effect of CysLT receptor antagonists on seizure frequency in kindled animals and changes in CysLT receptor expression after pentylenetetrazol (PTZ-induced kindling have not been investigated. In this study, we evaluated whether the CysLT1 inverse agonist montelukast, and a classical anticonvulsant, phenobarbital, were able to reduce seizures in PTZ-kindled mice and alter CysLT receptor expression. Montelukast (10 mg/kg, sc and phenobarbital (20 mg/kg, sc increased the latency to generalized seizures in kindled mice. Montelukast increased CysLT1 immunoreactivity only in non-kindled, PTZ-challenged mice. Interestingly, PTZ challenge decreased CysLT2 immunoreactivity only in kindled mice. CysLT1 antagonists appear to emerge as a promising adjunctive treatment for refractory seizures. Nevertheless, additional studies are necessary to evaluate the clinical implications of this research.

  5. Clinical features, pathogenesis and management of drug-induced seizures.

    Science.gov (United States)

    Zaccara, G; Muscas, G C; Messori, A

    1990-01-01

    Many classes of pharmacological agents have been implicated in cases of drug-induced seizures. The list includes antidepressant drugs, lithium salts, neuroleptics, antihistamines (H1-receptor antagonists), anticonvulsants, central nervous system stimulants, general and local anaesthetics, antiarrhythmic drugs, narcotic and non-narcotic analgesics, non-steroidal anti-inflammatory drugs, antimicrobial agents, antifungal agents, antimalarial drugs, antineoplastic drugs, immunosuppressive drugs, radiological contrast agents and vaccines. For each of these classes of drugs, this article offers a revision of the literature and emphasises in particular the frequency of the adverse reaction, its clinical presentation, its presumed epileptogenic mechanism and the therapeutic strategy for the management of drug-induced seizures. An attempt is also made to distinguish seizures induced by standard dosages from those provoked by accidental or self-induced intoxication. For some classes of drugs such as antidepressants, neuroleptics, central nervous system stimulants (e.g. theophylline, cocaine, amphetamines) and beta-lactam antibiotics, seizures are a well recognised adverse reaction, and a large body of literature has been published discussing exhaustively the major aspects of the issue; sufficient data are available also for the other classes of pharmacological agents mentioned above. In contrast, several other drugs [e.g. allopurinol, digoxin, cimetidine, protirelin (thyrotrophin releasing hormone), bromocriptine, domperidone, insulin, fenformin, penicillamine, probenecid, verapamil, methyldopa] have not been studied thoroughly under this aspect, and the only source of information is the occasional case report. This review does not address the issue of seizures induced by drug withdrawal. PMID:2182049

  6. The Best Time for EEG Recording in Febrile Seizure

    Directory of Open Access Journals (Sweden)

    Parvaneh KARIMZADEH

    2014-01-01

    Full Text Available How to Cite This Article: Karimzadeh P, Rezayi A, Togha M, Ahmadabadi F, Derakhshanfar H, Azargashb E, Khodaei F. The Best Time for EEG Recording in Febrile Seizure. Iran J Child Neurol. 2014 Winter; 8(1:20-25.ObjectiveSome studies suggest that detection of epileptic discharge is unusual during the first postictal week of febrile seizure and others believe that EEGs carried out on the day of the seizure are abnormal in as many as 88% of the patients. In thisstudy, we intend to compare early and late EEG abnormalities in febrile seizure.Materials & Methods EEG was recorded during daytime sleep, 24-48 hours (early EEG and 2 weeks (late EEG after the seizure in 36 children with febrile seizure (FS, aged between 3 months and 6 years. EEGs that showed generalized or focal spikes, sharp, spike wave complex, and slowing were considered as abnormal EEG.Abnormalities of the first EEG were compared with those of second EEG.ResultsThe most common abnormal epileptiform discharges recorded in the early EEG were slow waves (27.6% and sharp waves in late EEG (36%. Distribution of abnormalities in early and late EEG showed no significant statistical difference.ConclusionThe early and late EEG recording had the same results in patient with febrile seizure. Reference:Hauser WA, Kurland LT. The epidemiology of epilepsy in Rochester, Minnesota, 1935 through 1967. Epilepsia 1975;16(1:1-66.Freeman JM. Febrile seizures: a consensus of their significance, evaluation, and treatment. Pediatrics 1980;66(6:1009.Waruiru C, Appleton R. Febrile seizures: an update. Arch Dis Child 2004;89(8:751-6.ILAE. Guidelines for epidemiologic studies on epilepsy, International League against Epilepsy. Epilepsia 1993;34(4:592-6.Annegers JF, Hauser WA, Shirts SB, Kurland LT. Factors prognostic of unprovoked seizures after febrile convulsions. N Engl J Med 1987;316(9:493-8.Berg AT, Shinnar S, Darefsky AS, Holford TR, Shapiro ED, Salomon ME, et al. Predictors of recurrent febrile

  7. Refractory Seizures in Tramadol Poisoning: A Case Report

    Directory of Open Access Journals (Sweden)

    Mohammad Majidi

    2014-09-01

    Full Text Available Background: Tramadol, an analgesic drug abused by opioid addicts, is also abused accidentally or for suicidal purposes. Tramadol poisoning can induce CNS depression, seizures, coma, and ultimately death. Case: In this report, a 30-year-old male was admitted to the emergency department due to suicidal attempt with ingestion of 14000 mg (140 tablet 100 mg of tramadol. He had history of suicidal attempts in past years as well as depression in his past medical history, but he had not abused tramadol and other drugs in his history. There was no history of epilepsy or head trauma in. He presented with generalized seizures two hours post ingestion, and, then, he was referred to hospital four hours later. Generalized seizures were poorly controlled by multiple medications. Due to respiratory arrest, endotracheal tube was inserted and he was admitted to the ICU immediately. At admission, he experienced hypovolemic shock, hypoglycemia, coma, apnea, refractory seizures, muscle spasms, acute respiratory distress syndrome, coagolative disorder, rhabdomyolysis, and acute renal failure. Despite medical managements, he died 38 days after ingestion. Conclusion: In this report, despite using inhalational anesthetic drugs, seizures continued and were very poorly controlled. Cause of death in this patient can be seen as the side effects of tramadol poisoning.

  8. The effects of inferior olive lesion on strychnine seizure

    International Nuclear Information System (INIS)

    Bilateral inferior olive lesions, produced by systemic administration of the neurotoxin 3-acetylpyridine (3AP) produce a proconvulsant state specific for strychnine-induced seizures and myoclonus. We have proposed that these phenomena are mediated through increased excitation of cerebellar Purkinje cells, through activation of glutamate receptors, in response to climbing fiber deafferentation. An increase in quisqualic acid (QA)-displaceable [3H]AMPA [(RS)-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid] binding in cerebella from inferior olive-lesioned rats was observed, but no difference in [3H]AMPA binding displaced by glutamate, kainic acid (KA) or glutamate diethylester (GDEE) was seen. The excitatory amino acid antagonists GDEE and MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclo-hepten-5,10 imine] were tested as anticonvulsants for strychnine-induced seizures in 3AP inferior olive-lesioned and control rats. Neither drug effected seizures in control rats, however, both GDEE and MK-801 produced a leftward shift in the strychnine-seizure dose-response curve in 3AP inferior olive-lesioned rats. GDEE also inhibited strychnine-induced myoclonus in the lesioned group, while MK-801 had no effect on myoclonus. The decreased threshold for strychnine-induced seizures and myoclonus in the 3AP-inferior olive-lesioned rats may be due to an increase in glutamate receptors as suggested by the [3H]AMPA binding data

  9. Impacts of XBT, TAO, Altimetry and ARGO Observations on the Tropical Pacific Ocean Data Assimilation

    Institute of Scientific and Technical Information of China (English)

    YAN Changxiang; ZHU Jiang; ZHOU Guangqing

    2007-01-01

    This study aims at assessing the relative impacts of four major components of the tropical Pacific Ocean observing system on assimilation of temperature and salinity fields. Observations were collected over a period between January 2001 through June 2003 including temperature data from the expendable bathythermographs (XBT), thermistor data from the Tropical Ocean Global Atmosphere Tropical Atmosphere-Ocean (TOGA-TAO) mooring array, sea level anomalies from the Topex/Poseidon and Jason-1 altimetry (T/P-J),and temperature and salinity profiles from the Array for Real-time Geostrophic Oceanography (ARGO) floats.An efficient three-dimensional variational analysis-based method was introduced to assimilate the above data into the tropical-Pacific circulation model. To evaluate the impact of the individual component of the observing system, four observation system experiments were carried out. The experiment that assimilated all four components of the observing system was taken as the reference. The other three experiments were implemented by withholding one of the four components. Results show that the spatial distribution of the data influences its relative contribution. XBT observations produce the most distinguished effects on temperature analyses in the off-equatorial region due to the large amount of measurements and high quality.Similarly, the impact of TAO is dominant in the equatorial region due to the focus of the spatial distribution.The Topex/Poseidon-Jason-1 can be highly complementary where the XBT and TAO observations are sparse.The contribution of XBT or TAO on the assimilated salinity is made by the model dynamics because no salinity observations from them are assimilated. Therefore, T/P-J, as a main source for providing salinity data, has been shown to have greater impacts than either XBT or TAO on the salinity analysis. Although ARGO includes the subsurface observations, the relatively smaller number of observation makes it have the smallest

  10. UNIFICATION AND APPLICATIONS OF MODERN OCEANIC/ATMOSPHERIC DATA ASSIMILATION ALGORITHMS

    Institute of Scientific and Technical Information of China (English)

    QIAO Fang-li; ZHANG Shao-qing; YUAN Ye-li

    2004-01-01

    The key mathematics and applications of various modern atmospheric/oceanic data assimilation methods including Optimal Interpolation(OI),4-dimensional variational approach(4D-Var)and filters were systematically reviewed and classified.Based on the data assimilation philosophy,I.e.,using model dynamics to extract the observational information,the common character of the problem,such as the probabilistic nature of the evolution of the atmospheric/oceanic system,noisy and irregularly spaced observations,and the advantages and disadvantages of these data assimilation algorithms,were discussed.In the filtering framework,all modern data assimilation algorithms were unified: OI/3D-Var is a stationary filter,4D-Var is a linear(Kalman)filter and an ensemble of Kalman filters is able to construct a nonlinear filter.The nonlinear filter such as the Ensemble Kalman Filter(ENKF),Ensemble Adjustment Kalman Filter(EAKF)and Ensemble Transformation Kalman Filter(ETKF)can,to some extent,account for the non-Gaussian information of the prior distribution from the model.The flow-dependent covariance estimated by an ensemble filter may be introduced to OI and 4D-Var to improve these traditional algorithms.In practice,the performance of algorithms may depend on the specific numerical model and the choice of algorithm may depend on the specific problem.However,the unification of algorithms allows us to establish a unified test system to evaluate these algorithms,which provides more insights into data assimilation philosophies and helps improve data assimilation techniques.

  11. Data-assimilation by delay-coordinate nudging

    CERN Document Server

    Pazó, D; López, J M

    2015-01-01

    A new nudging method for data assimilation, delay-coordinate nudging, is presented. Delay-coordinate nudging makes explicit use of present and past observations in the formulation of the forcing driving the model evolution at each time-step. Numerical experiments with a low order chaotic system show that the new method systematically outperforms standard nudging in different model and observational scenarios, also when using an un-optimized formulation of the delay-nudging coefficients. A connection between the optimal delay and the dominant Lyapunov exponent of the dynamics is found based on heuristic arguments and is confirmed by the numerical results, providing a guideline for the practical implementation of the algorithm. Delay-coordinate nudging preserves the easiness of implementation, the intuitive functioning and the reduced computational cost of the standard nudging, making it a potential alternative especially in the field of seasonal-to-decadal predictions with large Earth system models that limit ...

  12. Sample size reduction in groundwater surveys via sparse data assimilation

    KAUST Repository

    Hussain, Z.

    2013-04-01

    In this paper, we focus on sparse signal recovery methods for data assimilation in groundwater models. The objective of this work is to exploit the commonly understood spatial sparsity in hydrodynamic models and thereby reduce the number of measurements to image a dynamic groundwater profile. To achieve this we employ a Bayesian compressive sensing framework that lets us adaptively select the next measurement to reduce the estimation error. An extension to the Bayesian compressive sensing framework is also proposed which incorporates the additional model information to estimate system states from even lesser measurements. Instead of using cumulative imaging-like measurements, such as those used in standard compressive sensing, we use sparse binary matrices. This choice of measurements can be interpreted as randomly sampling only a small subset of dug wells at each time step, instead of sampling the entire grid. Therefore, this framework offers groundwater surveyors a significant reduction in surveying effort without compromising the quality of the survey. © 2013 IEEE.

  13. Nonlinear balance constraints in 3DVAR data assimilation

    Institute of Scientific and Technical Information of China (English)

    ZHU; Jiang; YAN; Changxiang

    2006-01-01

    In many applications of 3DVAR, the balance constraints can be considered via two main approaches: weak constraint method which adds penalty terms to the cost function; and proper definition of the background error covariance matrix with non-zero cross-correlation sub-matrices. The weak constraint approach requires determining the weighting matrices of the penalty terms. The background error covariance approach does not require determining those additional weighting matrices. However, it is only applicable to those linear or linearized balance constraints. A novel approach is proposed based on the background error covariance approach by generalizing the so-called Derber-Bouttier formulation. An assimilation experiment of estimating temperature and salinity from the sea surface dynamic height observation is given to illustrate the proposed treatments of nonlinear balance constraints.

  14. Absence of seizures in Rasmussen encephalitis with active inflammation.

    Science.gov (United States)

    Samanta, Debopam; Gokden, Murat; Albert, Gregory W

    2016-06-01

    Severe focal motor epilepsy is considered a clinical hallmark of Rasmussen encephalitis (RE). The authors report a 6-year-old girl with progressive right sided hemiparesis, loss of language skills, left sided hemispheric atrophy, and brain pathologic features characteristic for RE. The patient did not experience seizures over a 2year period after symptom onset and for several months during follow-up. This report expands the clinical spectrum of RE and suggests that seizures are not a universal symptom of RE. Our patient's quite remarkable neurologic deficits along with active inflammation in the absence of epilepsy supports that, at least in some individuals, unilateral hemispheric progressive inflammation can occur without active seizure activity. PMID:26775150

  15. Seizure prediction using adaptive neuro-fuzzy inference system.

    Science.gov (United States)

    Rabbi, Ahmed F; Azinfar, Leila; Fazel-Rezai, Reza

    2013-01-01

    In this study, we present a neuro-fuzzy approach of seizure prediction from invasive Electroencephalogram (EEG) by applying adaptive neuro-fuzzy inference system (ANFIS). Three nonlinear seizure predictive features were extracted from a patient's data obtained from the European Epilepsy Database, one of the most comprehensive EEG database for epilepsy research. A total of 36 hours of recordings including 7 seizures was used for analysis. The nonlinear features used in this study were similarity index, phase synchronization, and nonlinear interdependence. We designed an ANFIS classifier constructed based on these features as input. Fuzzy if-then rules were generated by the ANFIS classifier using the complex relationship of feature space provided during training. The membership function optimization was conducted based on a hybrid learning algorithm. The proposed method achieved highest sensitivity of 80% with false prediction rate as low as 0.46 per hour. PMID:24110134

  16. Global Assimilation of EOS-Aura Data as a Means of Mapping Ozone Distribution in the Lower Stratosphere and Troposphere

    Science.gov (United States)

    Wargan, Krzysztof; Olsen, M.; Douglass, A.; Witte, J.; Strahan, S.; Livesey, N.

    2012-01-01

    Ozone in the lower stratosphere and the troposphere plays an important role in forcing the climate. However, the global ozone distribution in this region is not well known because of the sparse distribution of in-situ data and the poor sensitivity of satellite based observations to the lowermost of the atmosphere. The Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) instruments on EOS-Aura provide information on the total ozone column and the stratospheric ozone profile. This data has been assimilated into NASA s Global Earth Observing System, Version 5 (GEOS-5) data assimilation system (DAS). We will discuss the results of assimilating three years of OMI and MLS data into GEOS-5. This data was assimilated alongside meteorological observations from both conventional sources and satellite instruments. Previous studies have shown that combining observations from these instruments through the Trajectory Tropospheric Ozone Residual methodology (TTOR) or using data assimilation can yield useful, yet low biased, estimates of the tropospheric ozone budget. We show that the assimilated ozone fields in this updated version of GEOS-5 exhibit an excellent agreement with ozone sonde and High Resolution Dynamics Limb Sounder (HIRDLS) data in the lower stratosphere in terms of spatial and temporal variability as well as integrated ozone abundances. Good representation of small-scale vertical features follows from combining the MLS data with the assimilated meteorological fields. We then demonstrate how this information can be used to calculate the Stratosphere - Troposphere Exchange of ozone and its contribution to the tropospheric ozone column in GEOS-5. Evaluations of tropospheric ozone distributions from the assimilation will be made by comparisons with sonde and other in-situ observations.

  17. SERUM ZINC LEVELS IN CHILDREN WITH FEBRILE SEIZURES

    Directory of Open Access Journals (Sweden)

    Srinivasa

    2014-03-01

    Full Text Available Febrile seizures are the most common cause of convulsions in children and a frequent cause of emergency hospital admissions. Indian studies suggested that up to 10% of children experience a febrile seizure. Febrile seizures are defined as an event in infancy or childhood usually occurring between 6 months to 6 years of age associated with fever but without evidence of intracranial infection or defined cause. OBJECTIVES: To determine the frequency of low serum zinc level in children presenting with febrile seizures at tertiary care hospital, Bangalore. METHOD: This is an observational cross sectional study conducted at the Department of Pediatric Medicine, tertiary care hospital, Bangalore, from January 2013 to January 2014. Children (6 months to 6 years of age presenting with febrile seizures who satisfied inclusion and exclusion criteria were enrolled for the study. Cause of fever was determined after detailed history, physical examination and relevant investigations. Three milliliters centrifuged blood sample was preserved in acid washed test tube. Separated serum was used to measure serum zinc level by calorimetric method. RESULTS: Out of 100 children enrolled, male to female ratio was 1.4:1, 56% of children were below the age of 2 years with mean age of the children was 24 months. Upper respiratory tract infection was the most frequent cause of fever apparent in 70 children (70%, followed by dengue fever 11 children (11%, acute gastroenteritis 6 (6%, urinary tract infection and otitis media in 4 children each (8%, Viral fever in 5 child (5%. Frequency of low serum zinc level was 62% in children with febrile seizures. INTERPRETATION AND CONCLUSION: This study reveals that there is positive correlation between low serum zinc levels and febrile convulsions.

  18. Potent anti-seizure effects of D-leucine.

    Science.gov (United States)

    Hartman, Adam L; Santos, Polan; O'Riordan, Kenneth J; Stafstrom, Carl E; Hardwick, J Marie

    2015-10-01

    There are no effective treatments for millions of patients with intractable epilepsy. High-fat ketogenic diets may provide significant clinical benefit but are challenging to implement. Low carbohydrate levels appear to be essential for the ketogenic diet to work, but the active ingredients in dietary interventions remain elusive, and a role for ketogenesis has been challenged. A potential antiseizure role of dietary protein or of individual amino acids in the ketogenic diet is understudied. We investigated the two exclusively ketogenic amino acids, L-leucine and L-lysine, and found that only L-leucine potently protects mice when administered prior to the onset of seizures induced by kainic acid injection, but not by inducing ketosis. Unexpectedly, the D-enantiomer of leucine, which is found in trace amounts in the brain, worked as well or better than L-leucine against both kainic acid and 6Hz electroshock-induced seizures. However, unlike L-leucine, D-leucine potently terminated seizures even after the onset of seizure activity. Furthermore, D-leucine, but not L-leucine, reduced long-term potentiation but had no effect on basal synaptic transmission in vitro. In a screen of candidate neuronal receptors, D-leucine failed to compete for binding by cognate ligands, potentially suggesting a novel target. Even at low doses, D-leucine suppressed ongoing seizures at least as effectively as diazepam but without sedative effects. These studies raise the possibility that D-leucine may represent a new class of anti-seizure agents, and that D-leucine may have a previously unknown function in eukaryotes. PMID:26054437

  19. Imaging the seizure onset zone with stereo-electroencephalography.

    Science.gov (United States)

    David, Olivier; Blauwblomme, Thomas; Job, Anne-Sophie; Chabardès, Stéphan; Hoffmann, Dominique; Minotti, Lorella; Kahane, Philippe

    2011-10-01

    Stereo-electroencephalography is used to localize the seizure onset zone and connected neuronal networks in surgical candidates suffering from intractable focal epilepsy. The concept of an epileptogenicity index has been proposed recently to represent the likelihood of various regions being part of the seizure onset zone. It quantifies low-voltage fast activity, the electrophysiological signature of seizure onset usually assessed visually by neurologists. Here, we revisit epileptogenicity in light of neuroimaging tools such as those provided in statistical parametric mapping software. Our goal is to propose a robust approach, allowing easy exploration of patients' brains in time and space. The procedure is based upon statistical parametric mapping, which is an established framework for comparing multi-dimensional image data that allows one to correct for inherent multiple comparisons. Statistics can also be performed at the group level, between seizures in the same patient or between patients suffering from the same type of epilepsy using normalization of brains to a common anatomic atlas. Results are obtained from three case studies (insular reflex epilepsy, cryptogenic frontal epilepsy and lesional occipital epilepsy) where tailored resection was performed, and from a group of 10 patients suffering from mesial temporal lobe epilepsy. They illustrate the basics of the technique and demonstrate its very good reproducibility and specificity. Most importantly, the proposed approach to the quantification of the seizure onset zone allows one to summarize complex signals in terms of a time-series of statistical parametric maps that can support clinical decisions. Quantitative neuroimaging of stereo-electroencephalographic features of seizures might thus help to provide better pre-surgical assessment of patients undergoing resective surgery. PMID:21975587

  20. Evaluation of Risk Factors Associated with First Episode Febrile Seizure

    Science.gov (United States)

    Sharawat, Indar Kumar; Singh, Jitender; Singh, Amitabh

    2016-01-01

    Introduction Febrile seizure (FS) is the single most common type of seizure seen in children between 6 months to 5 years of age. The purpose of our study was to identify the risk factors associated with the first episode of febrile seizures, which would help in the better management and preventive measures in children at risk for FS episodes. Aim To evaluate the risk factors associated with the first episode of febrile seizures in Indian children. Materials and Methods This was a hospital based, case control study. The purpose of this study was to identify the risk factors associated with the first FS episode in children. Seventy (70) children between age 6 months to 5 years with their first episode of FS were compared with 70 children with fever but without seizures based on various risk factors. Results The mean age was 24.90±16.11 months in cases and 26.34±16.93 months in controls. Male: female ratio was 2:1. A positive family history was found in 31.4% of first degree and 11.4% in second degree relatives. Mean maximum temperature was 102.06±1.1°F and URI (upper respiratory infection) was most common cause of fever. Antenatal complication was significantly higher in the case group. RBC (Red Blood Cells) indices like lower mean haemoglobin, MCV (Mean Corpuscular Volume), MCH (Mean Corpuscular Haemoglobin concentration) and higher RDW (Red Cell Distribution Width) values were seen in patients. Serum sodium, Serum calcium and random blood sugar values of the cases were significantly lower than those of controls (pblood sugar and microcytic hypochromic anaemia are the risk factors associated with the occurrence of first episode of febrile seizure and, thus, preventive measures in removing these risk factors could lead to a decrease in incidence of FS.