8,201 research outputs found
Implications of parasitic absorption of electron cyclotron waves on ITER operation around half-field
Three obstructions: forms of causation, chronotopoids, and levels of reality
The thesis is defended that the theories of causation, time and space, and levels of reality are mutually interrelated in such a way that the difficulties internal to theories of causation and to theories of space and time can be understood better, and perhaps dealt with, in the categorial context furnished by the theory of the levels of reality. The structural condition for this development to be possible is that the first two theories be opportunely generalized
An evolutionary approach to feature selection and classification in P300-based BCI
We explore the use of evolutionary algorithms in the selection of features and the classification of P300 signals in BCI. As a result we have found new ways to process and combine EEG signals to improve detection
Ricerca ed innovazione migliorano la qualità della vita (occorre coraggio impegno e talvolta ribellione).
Coraggio, impegno e talvolta ribellione, non disgiunti dal necessario rispetto, sono le doti adatte a praticare ricerca ed innovazione. Meno importante è il campo di elezione, dalla scienza alla tecnica, come dalle lettere alle arti, con interessanti contaminazioni e fruttuose ibridazioni. La filosofia scientifica e la storia della scienza e della tecnica servono a mostrare, quanto fruttifera sia la via e quanto ben distinta dai retaggi spiritualisti, idealisti e storicisti. Infatti queste dottrine pretendono di fornire spiegazioni a priori e certezze assolute, quando la conoscenza della realtà è possibile solo con approssimazioni probabilistiche. In questo contesto, si colloca anche una concezione moderna delle discipline del rilevamento che devono sempre tener conto della grande complessità ed estrema variabilità della realtà fisica ed antropica
Analogue P300-based BCI pointing device
We propose a P300-based BCI mouse. The system is analogue: the pointer is controlled by directly combining the amplitudes of the outputs produced by a filter in the presence of different stimuli. The system is optimised by a genetic algorithm
Possible sources of perceptual errors in P300-based speller paradigm
Some perceptual phenomena can interfere with character identification in Farwell and Donchin's P300-based speller paradigm: attentional blink, repetition blindness and other effects caused by attentional limits. In the paper we discuss these and provide empirical evidence for one class of perceptual errors
Neural correlates of visuospatial working memory in the ‘at-risk mental state’
Background. Impaired spatial working memory (SWM) is a robust feature of schizophrenia and has been linked to
the risk of developing psychosis in people with an at-risk mental state (ARMS). We used functional magnetic
resonance imaging (fMRI) to examine the neural substrate of SWM in the ARMS and in patients who had just
developed schizophrenia.
Method. fMRI was used to study 17 patients with an ARMS, 10 patients with a first episode of psychosis and 15 agematched
healthy comparison subjects. The blood oxygen level-dependent (BOLD) response was measured while
subjects performed an object–location paired-associate memory task, with experimental manipulation of mnemonic
load.
Results. In all groups, increasing mnemonic load was associated with activation in the medial frontal and medial
posterior parietal cortex. Significant between-group differences in activation were evident in a cluster spanning the
medial frontal cortex and right precuneus, with the ARMS groups showing less activation than controls but greater
activation than first-episode psychosis (FEP) patients. These group differences were more evident at the most
demanding levels of the task than at the easy level. In all groups, task performance improved with repetition of the
conditions. However, there was a significant group difference in the response of the right precuneus across repeated
trials, with an attenuation of activation in controls but increased activation in FEP and little change in the ARMS.
Conclusions. Abnormal neural activity in the medial frontal cortex and posterior parietal cortex during an SWM task
may be a neural correlate of increased vulnerability to psychosis
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