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Álgebras algébricas absolutamente valuadas / Absolute valued algebraic algebrasArrieta, Eddie Arrieta 14 November 2012 (has links)
O objetivo da dissertação é provar que toda álgebra, sobre o corpo dos números reais, algébrica e absolutamente valuada é de dimensão nita, e portanto isótopa a D . Observamos que H é a álgebra real dos Quatérnios e D R , C , H ou a álgebra real dos Octônios. A demonstração do resultado é feita gradualmente, considerando inicialmente álgebras reais absolutamente valuadas algébrica com unidade, a seguir com unidade e nalmente, algébrica. Na demonstração do teorema será necessário combinar resultados não triviais de álgebras não associativas, análise funcional, álgebras de Banach e técnicas de ultraprodutos de espaços normados. As álgebra absolutamente valuadas não são necessariamente associativas. Abraham Adrian 1947 mostrou que R , C , H e D são as únicas álgebras reais absolutamente valuadas dimensão nita e com unidade; o mesmo Albert dois anos depois, em 1949 , caracterizou Albert em de essas mesmas álgebras como as únicas que são absolutamente valuadas algébricas e com unidade sobre os reais. Em 1960 Fred B. Wright e Kazimierz Urbanik provaram que R , C , D são as únicas álgebra reais absolutamente valuadas e com unidade. Recentemente, em 1997 , Kaidi El-Amin, Maria Isabel Ramírez e Ángel Rodríguez Palacios mostraram que H e toda álgebra real absolutamente valuadas e algébrica é isótopa a uma de estas quatro. Nosso objetivo é desenvolver e unicar os resultados obtidos nestes 4 trabalhos. / Our goal here is to study the absolute valued algebraic real algebras. In order to reach our intention, we regard an absolute valued real algebra and on which one we impose: First, such one is nite-dimensional algebra; second; such one is algebraic algebra; third, such one is with unity; and in the end such one is algebraic algebra. In the latter case, our aim, it needs of certain classic results of functional analysis and others one of Banach algebras; then, we reach that such one real algebra is isotope to one of the classical absolute valued real algebras algebra and D R , C , H or D . Where H is the Quaternions real is the Octonions real algebra. The absolute valued algebras are not necessarily associative. Abraham Adrian Albert was the rst mathematician considering absolute valued algebras in a context not necessarily associative. In 1947 , he proved that any nite-dimensional absolute valued real algebra with unit element is isomorphic to either real eld H or the Octonions algebra D . Two years R , the complex eld C , the Quaternions algebra later, he demonstrated that R , C , H and D are the unique absolute valued algebraic real algebras with unit element. Recently, in 1997 , Kaidi El-Amin, Maria Isabel Ramírez and Ángel Rodríguez Palacios proved that any absolute valued algebraic real algebra is nite-dimensional.
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Quantitative Measurement of Cerebral Hemodynamics During Activation of Auditory Cortex With Single- and Multi-Distance Near Infrared SpectroscopyMohammad, Penaz Parveen Sultana 29 June 2018 (has links)
Functional Near Infrared Spectroscopy (fNIRS) is a safe, low-cost, non-invasive opti-cal technique to monitor focal changes in brain activity using neurovascular coupling and measurements of local tissue oxygenation, i.e., changes in concentrations of oxygenated hemoglobin (HbO) and deoxygenated hemoglobin (HbR)[42]. This thesis utilizes two fNIRS approaches to measure hemodynamic changes associated with functional stimulation of the human auditory cortex. The first approach, single-distance continuous wave NIRS (CW-NIRS) utilizes relatively simple instrumentation and the Modified-Beer Lambert (MBL) law to estimate activation induced changes in tissue oxygenation (∆CHbO and ∆CHbR)[17]. The second more complex approach, frequency domain NIRS (FD-NIRS), employs a photon diffusion model of light propagation through tissue to measure both baseline (CHbO and CHbR), and stimulus induced changes in oxygenated and deoxygenated hemoglobin[10]. FD-NIRS is more quantitative, but requires measurements at multiple light source-detector separations and thus its use in measuring focal changes in cerebral hemodynamics have been limited.
A commercial FD-NIRS instrument was used to measure the cerebral hemodynamics from the right auditory cortex of 9 adults (21 ± 35 years) with normal hearing, while presented with two types of auditory stimuli: a 1000 Hz Pure tone, and Broad band noise. Measured optical intensities were analyzed using both MBL and photon diffusion approaches. Oxygenated hemoglobin was found to increase by 0.351 ± 0.116 µM and 0.060 ± 0.084 µM for Pure tone and Broad band noise stimuli, when analyzed by the MBL method at the ‘best’ source-detector separation. On average (across all sources), MBL analysis estimated an increase in CHbO of 0.100±0.075 µM and 0.099±0.084 µM respectively for Pure tone and Broad band noise stimulation. In contrast, the frequency domain analysis method estimated CHbO to increase by −0.401 ± 0.384 µM and −0.031 ± 0.358 µM for Pure tone and Broad band noise stimulation respectively. These results suggest that although more quantitative, multi-distance FD-NIRS may underestimate focal changes in cerebral hemodynamics that occur due to functional activation. Potential reasons for this discrepancy, including the partial volume effect, are discussed.
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Nova álgebra de Lie simples de dimensão 30 sobre um corpo de característica 2 / A new 30 dimensional simple lie algebra on a field of characteristic 2Osorio, Oscar Daniel Lopez 05 December 2016 (has links)
S.Skryabin demonstrou que qualquer álgebra de Lie simples de dimensão finita sobre um corpo de característica 2 possui posto toroidal 2. Duas 2- álgebras de Lie de dimensão 31 foram estudadas. Neste trabalho, mostramos que a primeira delas contem uma base toroidal absoluta de dimensão três, assim como a segunda, que foi estudada por Grishkov e Guerreiro anteriormente. Utilizando uma decomposicão de Cartan, exibimos um isomorfismo entre as duas 2- álgebras de Lie de dimensão 31. Este resultado foi sugerido depois de encontrar uma sub álgebra de dimensão 12 n ao solúvel e 7 isomorfas 2-sub álgebras de Lie de dimensão 7 nas duas álgebras. Finalmente, exploramos uma 2- álgebra de Lie de dimensão 34 como o fim de encontrar base toroidal absoluta de dimensão 4. Apoiamos os cálculos com algumas códigos no linguajem de MATLAB que permitiram optimizar e acelerar a pesquisa. / S.Skryabin showed that any finite dimensional simple Lie algebra over a field of characteristic 2 has absolute toral rank 2. Two 31-dimensional 2-algebras were known. In this work, we show that the first of these algebras, contains a 3-dimensional maximal toral subalgebra, as the second one, which was studied by Grishkov e Guerreiro previously. Using a Cartan decomposition we establish an isomorphism between the two 31-dimensional 2-algebras. This result was suggested after finding a 12-dimensional not soluble subalgebra and seven 7-dimensional isomorphic 2-subalgebras in both algebras. Finally, a 34-dimensional 2-Lie algebra was studied in order to find 4-dimensional maximal toral subalgebras. Some computations in this work were performed with help of MATLAB.
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絕對主體性與主客交互性--黑格爾邏輯學之「存有」、「本質」與「概念」諸範疇之必然連結關係的一種詮釋 / The absolute Subjectivity and the Interactivity between Subject and Object -An Interpretation about the Necessity of logical Connection between Being, Essence and Concept in Hegel's Science of Logic黃柏誠, Huang, Po Cheng Unknown Date (has links)
本篇研究論文所展現的研究任務和結果主要分為兩個方面,有如論文題目所呈現的:第一是黑格爾邏輯學之存有、本質與概念之必然連結如何可能;第二是範疇運動的最終目的之定位:絕對主體性與主客交互性。
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Agnostic democracy : the decentred "I" of the 1990sKang, Kathryn Muriel January 2005 (has links)
The thesis concerns the dynamics during the 1990s of political action by many groups of people, in what came to be called the movement of movements. The activists, who held that corporations were overstepping some mark, worked on alternative arrangements for self-rule. The thesis views the movement as micropolitics, using concepts devised by Deleuze and Guattari. It sets out particulars of the rhizomic make -up of the movement. A key point is that the movement trains participants in decentred organisation, which entails the forming of subject-groups as opposed to subjugated groups. The thesis records how the movement was shaped by earlier events in political action and thinking, especially from the 1960s on. The movement had previously been read as a push for absolute democracy (Hardt and Negri). The thesis shows that reading to have been incomplete: the movement is, in part, a push for agonistic democracy. More a practice than a form of rule, agonistic democracy is found where state power is bent on not moulding peoples into any unified polity. It is found where state power fosters conflicted-self-rule, so that every citizen may engage in the polity as a decentred "I". The thesis throws light on relations between the movement and the constitutionalist state. Part of the movement, while cynical about the existing form of state rule, wears a mask of obedience to constituted authority. When one upholds the fiction of legitimate rule, one can use the fiction as a restraint on the cynics-in-power. The play creates a shadow social contract, producing detente within the polity and within the �I.� The thesis also reports on a search in mainstream cinema for some expression of the movement's dynamics. The search leads to a cycle of thrillers, set in a nonfiction frame story about a coverup of gross abuse of state power.
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Advanced Techniques in Mass Spectrometry for Qualitative and Quantitative Protein CharacterizationDykstra, Andrew Boissy 01 August 2011 (has links)
Though mass spectrometry has earned a central role in the field of proteomics due to its versatility in a wide range of experiments, challenges and complications are still encountered when using mass spectrometry to characterize protein structures, post-translational modifications (PTMs), and abundances. In this dissertation, analytical methods utilizing mass spectrometry have been developed to address challenges associated with both qualitative and quantitative protein characterization. The effectiveness of using multiple pepsin-like proteases, both separately and in mixtures, combined with online proteolysis using a special triaxial probe has been demonstrated on an amyloid beta peptide related to the onset of Alzheimer’s disease. These findings have broad implications in protein structural characterization studies using hydrogen-deuterium exchange mass spectrometry. A wider range of proteases (Lys-C, Glu-C, and trypsin) and multiple fragmentation methods (collisionally activated dissociation, electron transfer dissociation, and decision tree) have been utilized in the discovery-based PTM characterization of extracellular cellulosome proteins of the bioenergy-relevent organism Clostridium thermocellum, resulting in the identification of 85 previously unknown modification sites in 28 cellulosome proteins. These modifications may contribute to the structure and/or function of the cellulosome protein complex. By using peptide internal standards and a triple quadrupole mass spectrometer operating in selected reaction monitoring mode, a method has been developed for the absolute quantitation of the Clostridium thermocellum cellulosome protein machine in samples ranging in complexity from purified cellulosome samples to whole cell lysates as an alternative to a previously-developed enzyme-linked immunosorbent assay method of cellulosome quantitation. The precision of the cellulosome mass concentration in technical replicates is better than 5% relative standard deviation for all samples, indicating high precision of cellulosome mass concentration for this method. Though methods and results presented in this dissertation have implications in the study of Alzheimer’s disease and bioenergy research, more broadly this dissertation focuses on development of methods to contend with some of the more complex challenges associated with protein characterization currently presented to the field of proteomics.
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Problems in the Classification Theory of Non-Associative Simple AlgebrasDarpö, Erik January 2009 (has links)
In spite of its 150 years history, the problem of classifying all finite-dimensional division algebras over a field k is still unsolved whenever k is not algebraically closed. The present thesis concerns some different aspects of this problem, and the related problems of classifying all composition and absolute valued algebras. A tripartition of the class of all fields is given, based on the dimensions in which division algebras over a field exist. Moreover, all finite-dimensional flexible real division algebras are classified. This class includes in particular all finite-dimensional commutative real division algebras, of which two different classifications, along different lines, are presented. It is shown that every vector product algebra has dimension zero, one, three or seven, and that its isomorphism type is determined by its adherent quadratic form. This yields a new and elementary proof for the corresponding, classical result for unital composition algebras. A rotation in a Euclidean space is an orthogonal map that locally acts as a plane rotation with a fixed angle. All pairs of rotations in finite-dimensional Euclidean spaces are classified up to orthogonal similarity. A description of all composition algebras having an LR-bijective idempotent is given. On the basis of this description, all absolute valued algebras having a one-sided unity or a non-zero central idempotent are classified.
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Global stability and feedback control of boundary layer flowsÅkervik, Espen January 2008 (has links)
In this thesis the stability of generic boundary layer flows is studied from a global viewpoint using optimization methods. Global eigenmodes of the incompressible linearized Navier-Stokes equations are computed using the Krylov subspace Arnoldi method. These modes serve as a tool both to study asymptotic stability and as a reduced basis to study transient growth. Transient growth is also studied using adjoint iterations. The knowledge obtained from the stability analysis is used to device systematic feedback control in the Linear Quadratic Gaussian framework. The dynamics is assumed to be described by the linearized Navier-Stokes equations. Actuators and sensors are designed and a Kalman filtering technique is used to reconstruct the unknown flow state from noisy measurements. This reconstructed flow state is used to determine the control feedback which is applied to the Navier-Stokes equations through properly designed actuators. Since the control and estimation gains are obtained through an optimization process, and the Navier-Stokes equations typically forms a very high-dimensional system when discretized there is an interest in reducing the complexity of the equations. A standard method to construct a reduced order model is to perform a Galerkin projection of the full equations onto the subspace spanned by a suitable set of vectors, such as global eigenmodes and balanced truncation modes. / QC 20100924
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The Success of Long-Short Equity Strategies versus Traditional Equity Strategies & Market ReturnsBuchanan, Lauren J. 01 January 2011 (has links)
This study examines the performance of long-short equity trading strategies from January 1990 to December 2010. This study combines two financial screens that will yield candidates for both long and short positions for each month during the aforementioned time period. Two long-short strategies are tested: (1) perfectly-hedged, or equal allocation to long and short positions, and (2) net-long. The results of this thesis reveal that if a long-short equity manager is able to successfully determine what companies are overvalued and undervalued and actively rebalance their portfolio, perfectly-hedged and net-long strategies can generate superior risk-adjusted alpha.
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Prediction Performance of Survival ModelsYuan, Yan January 2008 (has links)
Statistical models are often used for the prediction of
future random variables. There are two types of prediction, point
prediction and probabilistic prediction. The prediction accuracy is
quantified by performance measures, which are typically based on
loss functions. We study the estimators of these performance
measures, the prediction error and performance scores, for point and
probabilistic predictors, respectively. The focus of this thesis is
to assess the prediction performance of survival models that analyze
censored survival times. To accommodate censoring, we extend the
inverse probability censoring weighting (IPCW) method, thus
arbitrary loss functions can be handled. We also develop confidence
interval procedures for these performance measures.
We compare model-based, apparent loss based and cross-validation
estimators of prediction error under model misspecification and
variable selection, for absolute relative error loss (in chapter 3)
and misclassification error loss (in chapter 4). Simulation results
indicate that cross-validation procedures typically produce reliable
point estimates and confidence intervals, whereas model-based
estimates are often sensitive to model misspecification. The methods
are illustrated for two medical contexts in chapter 5. The apparent
loss based and cross-validation estimators of performance scores for
probabilistic predictor are discussed and illustrated with an
example in chapter 6. We also make connections for performance.
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