Improving California brush ranges /

C37

Detecting single-trial EEG evoked potential using a wavelet domain linear mixed model: application to error potentials classification

Objective. The main goal of this work is to develop a model for multi-sensor signals such as MEG or EEG signals, that accounts for the inter-trial variability, suitable for corresponding binary classification problems. An important constraint is that the model be simple enough to handle small size and unbalanced datasets, as often encountered in BCI type experiments. Approach. The method involves linear mixed effects statistical model, wavelet transform and spatial filtering, and aims at the characterization of localized discriminant features in multi-sensor signals. After discrete wavelet transform and spatial filtering, a projection onto the relevant wavelet and spatial channels subspaces is used for dimension reduction. The projected signals are then decomposed as the sum of a signal of interest (i.e. discriminant) and background noise, using a very simple Gaussian linear mixed model. Main results. Thanks to the simplicity of the model, the corresponding parameter estimation problem is simplified. Robust estimates of class-covariance matrices are obtained from small sample sizes and an effective Bayes plug-in classifier is derived. The approach is applied to the detection of error potentials in multichannel EEG data, in a very unbalanced situation (detection of rare events). Classification results prove the relevance of the proposed approach in such a context. Significance. The combination of linear mixed model, wavelet transform and spatial filtering for EEG classification is, to the best of our knowledge, an original approach, which is proven to be effective. This paper improves on earlier results on similar problems, and the three main ingredients all play an important role

Evaluating the use of cognitive-behavioral treatment programs in the federal probation system.

This study seeks to describe the number of United States Probation Offices using cognitive-behavioral treatment programs, which programs are being used, how referrals are made to the programs, if risk factors are considered in the referral process, how successful participants are in completing the programs, and how successful program completers are in successfully completing supervision. A survey was sent to U.S. Probation Offices across the country requesting information about those questions. In this study, the response rate was very low, approximately six percent, and the survey was submitted with varying degrees of information provided by respondents. This limited any conclusions that could be drawn from the data collected

What's an internal clock for? From temporal information processing to temporal processing of information

International audienceThe existence of an internal clock and its involvement in information processing has been investigated in humans using the experimental protocol of Treisman et al. (1990) [Treisman et al., 1990. Perception, 19, 705 – 743]. In this protocol, a periodical stimulation, which is assumed to drive an internal clock, is delivered during a reaction time (RT) task. The accelerating or slowing down effects of the periodical stimulation, according to its frequency, allowed an estimate to be made of a simple harmonic of the frequency of the internal clock. The estimate was close to 21 Hz. In the framework of the serial model of information processing, the present work investigates the involvement of the internal clock in the transmission of information between processing stages during RT. The data tend to support the idea that the internal clock allows the transfer of information from one stage to the next one at definite moments only, periodically distributed in time. According to our results, and recent data from the literature on electric cortical oscillations, we propose a model of an internal clock sending periodic inhibition, which would permit an increased signal/noise ratio in the processing and the transmission of information in the central nervous system

Ampliando a abertura dos bancos de germoplasma da Embrapa: experiências e atividades em andamento.

Edição dos resumos do IV Seminário de Agroecologia do Distrito Federal e Entorno, Brasília/DF

Predation Avoidance Mechanisms of Juvenile Arapaima spp.: Significance of Synchronized Breathing and Sound Production

Arapaima spp. are large, commercially important but poorly studied freshwater fishes endemic primarily to the Amazon and Essequibo rivers of South America. Arapaima are obligate air breathers with a modified lung-like swim bladder. Surfacing to respire exposes arapaima to a heightened predation risk, especially the small juveniles. Surfacing in synchrony could reduce predation risk of individual arapaima. Synchronous breathing has been observed with many air-breathing fish, but it has not been documented with arapaima. Many fishes also are known to produce characteristic sounds to startle predators when attacked, but such sounds have not been reported for arapaima. An investigation of predation defenses of juvenile arapaima was conducted by quantifying breathing frequency patterns over a diel cycle. Also, the ability to produce startle sounds was evaluated by simulating predation (i.e. grasping the fish). Young arapaima exhibited synchronized breathing throughout the day; mean number of arapaima per breathing event was significantly higher (