171,835 research outputs found
Wavelet analysis of oddball P300
No full textThe comparative wavelet analysis presented in details by Demiralp et al. (1999), Ademoglu (1995) and by Basar ct al. (2001) will be now applied to oddball P300 results (see Basar-Eroglu et al., 2001). The results obtained basically confirm those obtained by using adaptive digital filtering: The delta response dominates the P300 potential while the theta response is prolonged in a second late window. (C) 2001 Elsevier Science B.V. All rights reserved
Event-related theta oscillations: an integrative and comparative approach in the human and animal brain
No full textThis report provides a synthesis of results in both cat and human brains in order to point out the importance of theta responses during cognitive processes and P300 paradigms. The unique features of this report consisted of the fact that human and cat data during several cognitive paradigms were compared. The results open the way to formulate the selectively distributed theta system in the: brain as analyzed by Basar, Schurmann and Sakowitz (this issue). (C) 2001 Elsevier Science B.V. All rights reserved
Topological distribution of oddball 'P300' responses
No full textThis report describes the frequency response of the oddball paradigm upon auditory stimuli. Other reports related to wavelet analysis of the same ERPs (Demiralp et al., 1999) and the application of visual signals (Schurmann et al., this volume) indicate that the P300 response has a dominant delta response oscillation, independent of the modality of the stimulation. Moreover, the adaptive digital filtering and the wavelet analysis lead to very similar results, confirming that delta responses are real brain responses as already mentioned, by Basar et al. (this volume). The theta response has a second late response window in comparison to auditory evoked potentials. Moreover, the functional significance of the selectively distributed theta and delta systems of the brain will be clearly demonstrated. Signal detection, short-term memory, and decision-making processes are discussed. (C) 2001 Elsevier Science B.V. All rights reserved
Vittorino da Peltre as an Ideal Teacher
No full textVittorino da Feltre is presented here as an example of the lay teacher in Italy before the Reformation. He represents the type of schoolmaster now little known or almost forgotten, for which the Italy of that century was truly remarkable. Vittorino is not, however, to be considered merely as a teacher famous in Italy in the fifteenth century; he is offered here as an exemplary teacher for all times. Vittorino had that mysterious and indefinable quality which makes a born teacher. One of those men who devote their whole life to a cause for which their natural gifts constitute a special vocation, Vittorino synthesizes in his life and profession all that Is best in educational principles. Educators to-day might well look to him as an educational diagnostician and find in his theory remedies for the modern malignant diseases of triviality, vocationalism, and materialism.ProQuest Traditional Publishing Optio
Beta oscillations in face recognition
No full textThis report presents an analysis of the brain's beta oscillations in face recognition. We performed experiments on 26 subjects with a strategy consisting of two types of stimulations: (1) the picture of an elder anonymous lady (unknown face) and (2) the picture of the subject's own grandmother (known face). The subjects were healthy, young people between the ages of 15-32 years. Data were analyzed by means of amplitude frequency characteristics and digital filtering. Our results show the significant role of beta response in face recognition and the differentiation of known and unknown faces. Furthermore, this report supports our former view that the presentation of grandmother face evokes selectively distributed multiple oscillations in the brain. Together with the scope of other frequencies (e.g., delta, theta, and alpha), this method can serve as a tool for research studies or clinical studies in memory and cognition. (C) 2004 Elsevier B.V. All rights reserved
Oscillatory brain dynamics, wavelet analysis, and cognition
No full textOn the basis of a systems theoretical approach it was hypothesized that event-related potentials (ERPs) are superpositions of stimulus-evoked and time-locked EEG rhythms reflecting resonance properties of the brain (Basar, 1980). This approach led to frequency analysis of ERPs as a way of analyzing evoked rhythms. The present article outlines the basic features of ERP frequency analysis in comparison to ERP wavelet analysis, a recently introduced method of time-frequency analysis. Both methods were used in an investigation of the functional correlates of evoked rhythms where auditory and visual ERPs were recorded from the cat brain. Intracranial electrodes were located in the primary auditory cortex and in the primary visual cortex thus permitting ''cross-modality'' experiments. Responses to adequate stimulation (e.g., visual ERP recorded from the visual cortex) were characterized by high amplitude alpha (8-16 Hz) responses which were not observed for inadequate stimulation. This result is interpreted as a hint at a special role of alpha responses in primary sensory processing. The results of frequency analysis and of wavelet analysis were quite similar, with possible advantages of wavelet methods for single-trial analysis. The results of frequency analysis as performed earlier were thus confirmed by wavelet analysis. This supports the view that ERP frequency components correspond to evoked rhythms with a distinct biological significance. (C) 1999 Academic Press
Subdivision of the spectra for difference operator over certain sequence space
No full textIn a series of papers, B. Altay, F. Basar and A. M. Akhmedov recently investigated the spectra and fine spectra for difference operator, considered as bounded operator over various sequence spaces. In the present paper approximation point spectrum, defect spectrum and compression spectrum of difference operator ? over the sequence spaces c 0, c, ? p and b? p are determined, where b? p denotes the space of all sequences (x k) such that (x k-x k-1) belongs to the sequence space ? p and 1 < p <?.Basar, F.; Department of Mathematics, Fatih University, Istanbul, Turkey; email: [email protected]
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Some Euler spaces of difference sequences of order m
No full textKizmaz [13] studied the difference sequence spaces l(infinity)(Delta), c(Delta), and c(o)(Delta). Several article dealt with the sets of sequences of m-th order difference of which are bounded, convergent, or convergent to zero. Altay and Basar [5] and Altay, Basar, and Mursaleen [7] introduced the Euler sequence spaces e(o)(r), e(c)(r), and e(infinity)(r), respectively. The main purpose of this article is to introduce the spaces e(o)(r)(Delta((m))), e(c)(r)(Delta((m))), and e(infinity)(r)(Delta((m))) consisting of all sequences whose m(th) order differences are in the Euler spaces e(o)(r), e(c)(r), and e(infinity)(r), respectively. Moreover, the authors give some topological properties and inclusion relations, and determine the alpha-, beta-, and gamma-duals of the spaces e(o)(r)(Delta((m))), e(c)(r)(Delta((m))), and e(infinity)(r)(Delta((m))), and the Schauder basis of the spaces e(o)(r)(Delta((m))), e(c)(r)(Delta((m))). The last section of the article is devoted to the characterization of some matrix mappings on the sequence space e(c)(r)(Delta((m)))
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