Contribuições para a análise de sinais neuronais e biomédicos

Following the new tendency of interdisciplinarity of modern science, a new field called neuroengineering has come to light in the last decades. After 2000, scientific journals and conferences all around the world have been created on this theme. The present work comprises three different subareas related to neuroengineering and electrical engineering: neural stimulation; theoretical and computational neuroscience; and neuronal signal processing; as well as biomedical engineering. The research can be divided in three parts: (i) A new method of neuronal photostimulation was developed based on the use of caged compounds. Using the inhibitory neurotransmitter GABA caged by a ruthenium complex it was possible to block neuronal population activity using a laser pulse. The obtained results were evaluated by Wavelet analysis and tested by non-parametric statistics. (ii) A mathematical method was created to identify neuronal assemblies. Neuronal assemblies were proposed as the basis of learning by Donald Hebb remain the most accepted theory for neuronal representation of external stimuli. Using the Marcenko-Pastur law of eigenvalue distribution it was possible to detect neuronal assemblies and to compute their activity with high temporal resolution. The application of the method in real electrophysiological data revealed that neurons from the neocortex and hippocampus can be part of the same assembly, and that neurons can participate in multiple assemblies. (iii) A new method of automatic classification of heart beats was developed, which does not rely on a data base for training and is not specialized in specific pathologies. The method is based on Wavelet decomposition and normality measures of random variables. Throughout, the results presented in the three fields of knowledge represent qualification in neural and biomedical engineering

A metafísica de Isaac Newton

The general objective of this dissertation is to analyze the metaphysical aspects of "rational mechanics" of Isaac Newton, clarifying, by scientific and philosophical discourse, their main elements, with emphasis to the presence of one entity infinitely rational behind all the phenomena of nature, and to the Newton's insight as certain empiricist which, however, accepts deductions metaphysics; a philosopher-scientist. The specific objectives are detailed below: a) brief presentation of the development of modern science, since the Pre-Socratics, seeking to understand the historical conjecture that enabled the rise of Newtonian mechanics; b) presentation of the elements of scientific methodology and philosophical, aimed at comprehension of certain "Newtonian methodology", understanding how this specific methodology able to present empirical aspects, mathematics, philosophic and religious in communion; c) to understand, from the Newtonian concepts, both concerning man's role in the world as the "notional notions" of mass, space, time and movement, necessary for analysis and understanding of certain metaphysical aspects in the Newtonian physics; d) to present the Newtonian concepts related to the ether, to understand why it necessarily assumes metaphysics characteristics and mediation between the bodies; e) to present and understand the factors that lead the empiricist Newton to assume the religion in his mechanics, as well as, the existence and functions of God in nature, to object to the higher content of his metaphysics; f) to highlight the metaphysical elements of his classical mechanics, that confirm the presence of concepts like God Creator and Preserver of the natural laws; g) at last, to analyze the importance of Newton to the modern metaphysics and the legacy to philosophy of science at sec. XVII to science contemporary

Heidegger e a técnica moderna

The general objective of this research is to clarify and discuss the original contribution of Martin Heidegger's philosophical reflection on the essence of modern technique. For this purpose, it was structured the interpretative course of this dissertation in two essential moments. At first, we present Heidegger's interpretation of the essence of the modern age which, in turn, will be recognized from the metaphysical foundation that establishes the essence of modern science: the subjectivity that represents, calculates, manages and produces the real. We will see which, in this context, modern science was still thought close to the modern technology, what will change considerably from the writings of the post-war, in which Heidegger thinks modern science from a much broader and essential process in that the essence of the technique has already been unfolding. Thus, in a second moment, we will analyze how, for Heidegger, the modern metaphysics of subjectivity reached its completion at the time of modern art from the principle of control and planning of entities in general (Gestell), revealing the nontechnical sense of the technique (beyond the anthropological, humanistic and instrumental view) as well as the threatening character of modern technique in its conversion project of the entity from the reserve fund (Bestand).

Lacan, Gödel, a ciência e a verdade

Jaques Lacan, the thinker who proposes a return to the fundamentals of psychoanalysis in Freud states that the math would face as a privileged way of transmission of knowledge by the science. Although he was a follower of the mathematization of nature as the foundation of modern science, for him this principle does not imply eliminating the subject that produces it. That would be equivalent to saying that there can not be a language, whatever, even the math, that may "erases" the subject assumption in science. In the text The science and the truth we will try to introduce the idea, not so simple, by the way, the truth as the cause. Citing the framework of the causes in Aristotle, Lacan will speak of a homology between the truth as formal cause, in the case of science, and the truth as material cause, on the side of psychoanalysis. Among its aims with this text, he wants to establish that the unconscious of the subject would be none other than the subject of science. The famous incompleteness theorems of logical-mathematical Kurt Gödel enter here as a chapter of this issue. Recognized as true watershed, these theorems have to be remembered as revealing even outside the mathematical environment, and Lacan himself is not indifferent to this. He makes mention of Gödel's name and draws some observations apparently modest support for his own theory. Since some technical sophisticated knowledges awaits the reader who intends understand this supposed corroboration that Gödel provides to psychoanalysis, introduce the student of Lacan in the use he makes of the incompleteness theorems is the objective of this work. In The science and the truth, which fits us to locate the name of Gödel, one must question how seize such an idea without incurring the extrapolation and abuse of mathematical knowledge, almost trivial in this case. Thus, this paper aims to introduce the reader to the reasoning behind the theorems of Gödel, acquaint him about the Lacan’s mathematical claims, and indicate how to proceed using this implicit math in the text The science and the truth.