Improvements of Adaptive Filtering by Optimal Projection to filter different artifact types on long duration EEG recordings

Adaptive Filtering by Optimal Projection (AFOP) is an automatic method for reducing ocular and muscular artifacts on electro-encephalographic (EEG) recordings. This paper presents two additions to this method: an improvement of the stability of ocular artifact filtering and an adaptation of the method for filtering electrode artifacts. With these improvements, it is possible to reduce almost all the current types of artifacts, while preserving brain signals, particularly those characterising epilepsy. This generalised method consists of dividing the signal into several time-frequency windows, and in applying different spatial filters to each. Two steps are required to define one of these spatial filters: the first step consists of defining artifact spatial projection using the Common Spatial Pattern (CSP) method and the second consists of defining EEG spatial projection via regression. For this second step, a progressive orthogonalisation process is proposed to improve stability. This method has been tested on long-duration EEG recordings of epileptic patients. A neurologist quantified the ratio of removed artifacts and the ratio of preserved EEG. Among the 330 artifacted pages used for evaluation, readability was judged better for 78% of pages, equal for 20% of pages, and worse for 2%. Artifact amplitudes were reduced by 80% on average. At the same time, brain sources were preserved in amplitude from 70% to 95% depending on the type of waves (alpha, theta, delta, spikes, etc.). A blind comparison with manual Independent Component Analysis (ICA) was also realised. The results show that this method is competitive and useful for routine clinical practice.     

Antifibrotic and hemodynamic effects of the early and chronic administration of octreotide in two models of liver fibrosis in rats

The aim of this study was to assess the effect of the early and chronic administration of octreotide in the prevention of hepatic fibrosis and portal hypertension (PHT). Two experimental models of liver fibrosis caused by bile duct ligation (BDL) or CCl4 were divided into 4 rat groups: sham, placebo, and octreotide (10 and 100 micrograms/kg twice daily, subcutaneously). Liver fibrosis was assessed by the area of fibrosis (image analysis), liver hydroxyproline and fibronectin mRNA contents, and serum hyaluronate. Systemic and splanchnic hemodynamic changes were also evaluated, including the splenorenal shunt blood flow by the transit-time ultrasound (TTU) technique. In both models, splenorenal shunt blood flow was significantly lower in the octreotide groups than in the placebo group (P <.05), while portal pressure was not significantly decreased. There was a significant decrease in fibrosis by octreotide in the CCl4 model only: area of fibrosis: 13.9% +/- 3.7% vs. 9.8% +/- 2.5% (P <.01), hydroxyproline: 1.8 +/- 0.6 vs. 1.3 +/- 0.4 mg/g wet liver (P <.05), respectively, placebo vs. octreotide 10 micrograms/kg. There was a significant correlation between the area of fibrosis and hydroxyproline liver content (r =.87 in the biliary model and r =.91 in the CCl4 model; P <.0001). The early and chronic administration of octreotide prevents the development of portocollateral blood flow without reducing portal pressure in two models of liver fibrosis and the development of liver fibrosis in the CCl4 model.     

A statistical model of FM-TV spectra for satellite interference and distortion prediction

The requirement for a model of FM-TV spectra in the planning procedure of satellite communication systems is introduced. Based on long-term measurements of live TV channels, statistical properties of video spectra are examined and probability distributions for the luminance and chrominance components are proposed. The spectrum of the frequency-modulated signal is then derived, and signal distortion due to bandlimiting is calculated. Adjacent and cochannel interference effects are also investigated, with example cases illustrating influences of subcarrier loading and energy dispersion. The proposed model, which describes FM-TV spectra in terms of random variables, makes it possible to examine relative effects of system parameters, and will, therefore, be of benefit in the planning of new satellite services.     

Compatibility of Video and Data Signals on the Same Satellite Television Channel

Satellite television systems may employ subcarriers for additional transmission of data via the same channel thus utilizing satellite transponders more efficiently. Data-rate and bit-error-rate of such systems are ultimately limited by maximal-permissible subcarrier levels which would not degrade the picture quality significantly.     

How to base continuing medical education (CME) on the concepts of evidence and decision

In order to play its part fully, CME in France must be radically reformed, less in its methods than in its philosophy; it is important to ground CME on objective evaluation, evidence-based medicine and on medical decision making. These notions are often neglected, or even unrecognized, especially in medical education. Asset of actual situation are the recent decision of CME legal obligation, which will require validation of quality criterion in CME, and large network of associations and 'leader-practioners', that would let to most practicing physicians' participation.     

Comparative analysis and performance of two predictive fadedetection schemes for Ka-band fade countermeasures

The design of Ka-band satellite fade countermeasure (FCM) systems is conditioned by the detection/prediction algorithm to be included within practical DSP-based FCM controllers. It depends upon the ability of systems to efficiently integrate the dynamic and stochastic nature of the Ka-band fading process which is dominated by rain attenuation and amplitude scintillation. The paper analyzes the modeling and statistical performance of two predictive fade detection algorithms. Prediction is introduced as a way to minimize the impact of the finite response time on the BER/throughput of practical FCM systems. Both fixed (FDM) and variable (VDM) detection margin strategies are introduced and compared in terms of their margin requirements, FCM utilization factor, and channel capacity utilization. The VDM is shown to be more efficient than its fixed counterpart. The long-term BER availability and average user data throughput of a VDM/fixed-FEC/adaptive transmission rate FCM are then evaluated for a typical low-power low-rate Ka-band in-bound VSAT link     

Approaches to modelling FM video spectra for satellite signalinterference prediction

Three approaches to modelling FM video spectra which include energy dispersal are described. The first method is an analytical approach minimizing computer processing time. The second gives a more complete solution using numerical methods. In the third approach a statistical model is proposed with particular application to interference analysis. Each approach has both advantages and disadvantages, the most suitable method must be chosen depending on the application and availability of data. With limited data samples it is probable that one of the first two techniques can be used. The analytical approach minimizes computation time but is only effective around the carrier. The numerical analysis provides a more complete approach but requires substantial computer processing. Hence, for CCI (cochannel interference) analysis, the analytical method is acceptable. For an ACI (adjacent-channel interference) problem, the FFT (fast Fourier transform) approach is more realistic. The final method relies on the existence of the system to enable extensive data collection to be carried out     

Distribution of fasting serum insulin measured by enzyme immunoassay in an unselected population of 4,032 individuals. Reference values according to age and sex. D.E.S.I.R. Study Group. Données Epidémiologiques sur le Syndrome d''Insulino-Résistance

The effects of tumor necrosis factor alpha (TNF-alpha) on arachidonic acid (AA) metabolism were investigated by prelabeling the human osteoblastic osteosarcoma cell line, G292, with [3H]AA. TNF-alpha differentially stimulates cyclooxygenase and lipoxygenase pathways of AA metabolism in a dose response manner in the cells. The highest concentration of TNF-alpha (10(-8)M) significantly increased the cyclooxygenase pathway, with prostaglandin E2 (PGE2) being a major product. However, at the lowest concentration (10(-10)M) of TNF-alpha, 15-hydroxyeicosatetraenoic acid (HETE) production was significantly increased, with no significant effects on the other identifiable products. When the concentration of TNF-alpha was increased to 10(-9) M leukotriene B4 (LTB4), 15-, 12-, and 5-HETE were significantly increased. The calcium ionophore A23187 (10(-6) M) significantly increased 15-HETE production, without significantly affecting cyclooxygenase metabolites. However, a combination of TNF-alpha (10(-8)M) and A23187 (10(-6)M) caused an inhibitory effect on each agent-induced PGE2 or 15-HETE production.     

An attempt to improve blood pressure control in the French population: information and outcome awareness at the general practitioner level

To improve blood pressure (BP) control in general practice, 3122 general practitioners agreed to participate in a result awareness program. A survey carried out 6 months after participating physicians had been informed of the outcome of treatments they had given showed that blood pressure control (cut-off point: BP < 140/90 mm Hg) had not improved. However, using less stringent criteria, a slight improvement in blood pressure control could be observed. Although this improvement was marginal, results are sufficiently encouraging to warrant another study after a new awareness campaign among the medical population.