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537.635 --- Academic collection --- 537.635 Magnetic resonances --- Magnetic resonances --- # BIBC : Academic collection
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Theoretical spectroscopy. Spectroscopic techniques --- fysicochemie --- Atomic physics --- 537.635 --- #WNAT:didaktiek --- Magnetic resonances --- 537.635 Magnetic resonances
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Deze thesis behandelt twee nieuwe bijdragen tot de analyse van fMRI ( functional Magnetic Resonance Imaging ) signalen. De signalen werden verkregen door de hersenen van een primaat gedurende een bepaalde tijd te observeren met behulp van een MRI scanner. Een eerste bijdrage bestaat uit een nieuwe clustermethode. K-means en Fuzzy Cluster Analysis , zijn al langer in gebruik voor fMRI analyse, maar ze steunen op lineaire concepten. Onze nieuwe methode maakt gebruik van het Procaccia-Grassberger theorema uit het domein van de niet-lineaire toestandsdynamica. De bekomen resultaten tonen aan dat onze methode beter overweg kan met het niet-lineaire karakter van fMRI signalen, en dat onze methode minder ruisgevoelig is en meer focusseert op die delen van de hersenen die mogelijk op verschillende wijze geactiveerd worden door de aangelegde stimuli. De tweede bijdrage is een uitbreiding voor de Mann-Whitney statistische test, de Kolmogorov-Smirnov test (KS) en de Cramèr-von Mises test (CvM) om een niet-parametrische statistische analyse van fMRI signalen mogelijk te maken. Statistische testen worden gebruikt om na te gaan of een bepaald hersengebied op een significante wijze responsief is op een bepaalde (set van) stimuli. Onze uitbreiding corrigeert voor de aanwezigheid van autocorrelaties in fMRI signalen en maakt hierdoor de toepassing van de genoemde niet-parametrische testen mogelijk. Ten opzichte van de huidige parametrische testen, zoals de Student t -test, die enkel een verschil in de gemiddelde activatie kunnen nagaan, kunnen we door middel van de KS en CvM testen nu ook nagaan of er een verschil is in de aard van de activatie. Dit laatste, in combinatie met de andere klassieke testen, levert ons extra informatie op aangaande de werking van de hersenen. Samen met onze modelvrije clustermethode, levert deze contributie een beter inzicht in de werking van ons brein. This thesis discusses two new contributions to the analysis of fMRI ( functional Magnetic Resonance Imaging ) signals. The signals were obtained by scanning the brains of primates using an MRI scanner. The first contribution is an enhanced cluster tool. K-means and Fuzzy Cluster Analysis are often used for fMRI signal analysis to detect activity patterns in the brain, but they are based on linear concepts. Conversely, our novel cluster tool is based on the Procaccia-Grassberger theorem, which is well-known in the field of non-linear state dynamics. The obtained results show that our method is better adapted to handle the non-linear nature of fMRI signals, and that it is less sensitive to noise, which makes that the obtained clusters are more related to brain regions that are responding differentially to the applied stimuli. The second contribution is an extension to nonparametric statistical tests such as the Mann-Whitney test, the Kolmogorov-Smirnov test (KS) and the Cramèr-von Mises test (CvM). Statistical tests are used to check whether a given brain region is significantly responsive to a (set of) stimuli. Our extension corrects for the omni-present autocorrelations in fMRI signals, which consequently enables the use of these nonparametric tests for fMRI signals analysis. With respect to the current, parametric tests like the Student t -test, which can only detect a difference in the average activation, the KS and CvM tests can detect differences in the nature of the activation. In combination with the traditionally-used statistical tests, this is a source of additional information. Together with the novel cluster tool we developed, this contribution is expected to increase our insight into the functioning of the brain. Het onderwerp van deze thesis bespreekt een verbetering en een aanvulling van de technieken die momenteel gebruikt worden om de hersenactiviteit te analyseren die opgemeten is door middel van functionele Magnetische Resonantie Imaging (fMRI). Dergelijke analyses laten ons toe om de werking van de hersenen in vivo te bestuderen. Een goede analyse en interpretatie van de opgemeten signalen maakt dat we niet alleen beter (de werking van) onze hersenen begrijpen, maar dat we ook beter gaan verstaan wat er juist verkeerd gaat als een bepaalde cerebrale aandoening voorvalt. De verbetering besproken in deze thesis behandelt een nieuwe exploratieve data-analyse methode welke gebaseerd is op niet-lineaire principes. Aldus kan het gedrag van de hersenen beter waargenomen worden aangezien hun gedrag ook niet-lineair is. Een tweede deel behandelt een uitbreiding welke de toepassing van niet -parametrische statistische testen toelaat. Statistische testen worden gebruikt om de mate van responsiviteit van de hersenen op bepaalde externe factoren wiskundig te kwantificeren. Het voordeel van het gebruik van niet-parametrische testen ten opzichte van parametrische is dat deze eersten meer details van de hersenactiviteit in rekening brengen. Beide technieken zijn complementair maar bieden elk al afzonderlijk een meerwaarde door het feit dat elk meer details in ogenschouw neemt om tot resultaten te komen. Aldus wordt ons inzicht in de werking van de hersenen vergroot. This thesis discusses both an improvement and an extension of the tools that are being used nowadays to analyse brain-activity by means of functional Magnetic Resonance Imaging (fMRI). These analyses allow one to explore the functioning of the brain in vivo . A good analysis and interpretation of the recorded signals improves not only our knowledge of the healthy brain, but helps us also to understand the different mechanisms that are at the basis of some cerebral diseases. The mentioned improvement is the development of a new explorative data analysis method that is based on non-linear principles. Consequently, we can better detect the behaviour of the brain which is shown to be non-linear as well. A second part of this thesis deals with an extension for nonparametric statistical tests to allow their application to fMRI signals. Statistical tests are used to express the response of the brain to some external stimuli in a mathematical way. The advantage of the application of nonparametric tests is the fact that the outcome is based on more details of the nature of the brain activity than when parametric tests would have been used. Both methods are complementary, but are already very valuable since the results obtained with them are based on more details, i.e ., information. Consequently, this additional information increases our insight into the functioning of the brain.
Academic collection --- 537.635 --- 612.8 --- 537.635 Magnetic resonances --- Magnetic resonances --- Nervous system. Sensory organs --- Theses
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WAVE --- RADIOWAVE RADIATION --- ELECTROMAGNETIC WAVES --- STANDING WAVES, ACOUSTIC --- ELECTROSTATICS --- RESONANCES --- OPTICAL PROPERTIES --- RADIOMETERS --- WAVE --- RADIOWAVE RADIATION --- ELECTROMAGNETIC WAVES --- STANDING WAVES, ACOUSTIC --- ELECTROSTATICS --- RESONANCES --- OPTICAL PROPERTIES --- RADIOMETERS
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This second edition of the well-known work stresses important aspects of magnetic resonance theory that are of increasing importance to the research worker. Presents mathematical background and the basic prototype two-spin 1/2-1/2 Hamiltonian treatment as a building block to the more specialized subjects developed: higher spins and anistropies, applications to atomic spectra, crystal field theory, Mossbauer resonance, types of double resonance, and dynamic polarization. Specialized extensions are then discussed at length, with the advantage of showing clearly their relationships to the main body of magnetic resonance theory: ENDOR, ELDOR, polarization, spin labels, saturation transfer and fourier transform methods, and NMR imaging. Much of this material is treated by means of the uniform formalism based on the direct product matrix expansion technique.
Electromagnetism. Ferromagnetism --- Magnetic properties of solids --- Magnetic resonance --- 537.635 --- 541.67 --- #WSCH:AAS2 --- Resonance, Magnetic --- Atoms --- Magnetic fields --- Nuclear spin --- Magnetic resonances --- Relation of chemical structure to electrical and magnetic properties --- Magnetic resonance. --- 541.67 Relation of chemical structure to electrical and magnetic properties --- 537.635 Magnetic resonances
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A clear and comprehensive account of the basic principles involved in all quantum optical resonance phenomena, directed to graduate students and research physicists, and hailed in Contemporary Physics as "a valuable contribution to the literature of non-linear optics." 53 illustrations. Preface. Index. Lists of references.
Optics. Quantum optics --- Lasers --- Optical resonance --- 535.374 --- 537.635 --- Luminescence --- Quantum optics --- Resonance --- Light amplification by stimulated emission of radiation --- Masers, Optical --- Optical masers --- Light amplifiers --- Light sources --- Optoelectronic devices --- Nonlinear optics --- Optical parametric oscillators --- Amplification of radiation by stimulated emission --- Magnetic resonances --- Lasers. --- Optical resonance. --- 537.635 Magnetic resonances --- 535.374 Amplification of radiation by stimulated emission --- Acqui 2006
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Nuclear magnetic resonance --- 543.422.25 --- 537.635 --- 537 --- Using high frequency electromagnetic waves (radio waves). Nuclear manetic resonance spectroscopy. NMR spectroscopy --- Magnetic resonances --- Electricity. Magnetism. Electromagnetism --- 537 Electricity. Magnetism. Electromagnetism --- 537.635 Magnetic resonances --- 543.422.25 Using high frequency electromagnetic waves (radio waves). Nuclear manetic resonance spectroscopy. NMR spectroscopy
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537.635 --- Magnetic resonances --- Magnetic resonance imaging. --- Magnetic Resonance Imaging --- Mathematics. --- methods. --- 537.635 Magnetic resonances --- Magnetic resonance imaging --- Clinical magnetic resonance imaging --- Diagnostic magnetic resonance imaging --- Functional magnetic resonance imaging --- Imaging, Magnetic resonance --- Medical magnetic resonance imaging --- MR imaging --- MRI (Magnetic resonance imaging) --- NMR imaging --- Nuclear magnetic resonance --- Nuclear magnetic resonance imaging --- Cross-sectional imaging --- Diagnostic imaging --- Diagnostic use --- Methods.
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Nuclear magnetic resonance spectroscopy. --- Polymers --- Additives --- Spectra. --- Nuclear magnetic resonance spectroscopy --- 535.33 --- 537.635 --- Polymere --- Polymeride --- Polymers and polymerization --- Macromolecules --- NMR spectroscopy --- Spectroscopy, NMR --- Spectroscopy, Nuclear magnetic resonance --- Nuclear spectroscopy --- Knight shift --- Additives&delete& --- Spectra --- 537.635 Magnetic resonances --- Magnetic resonances --- 535.33 Spectra in general. Emission spectra --- Spectra in general. Emission spectra
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