No description available.

No description available.

No description available.

It is widely accepted that the cortex can be divided into a series of spatially discrete areas based on their specific laminar patterns. It is of great interest to divide the cortex into different areas in terms of both neuronal functions and cellular composition. The division of cortical areas can be reflected by the cell arrangements or cellular composition. Therefore, the cortical structure can be represented by some functional neuronal density data. Techniques on functional data analysis help to develop some measures which indicate structural changes. / In order to separate roughness from structural variations and influences of the convolutions and foldings, a method called bivariate smoothing is proposed for the noisy density data. This smoothing method is applied to four sets of cortical density data provided by Prof Petrides [1] and Scott Mackey [2]. / The first or second order derivatives of the density function reflect the change and the rate of the change of the density, respectively. Therefore, derivatives of the density function are applied to analyze the structural features as an attempt to detect indicators for boundaries of subareas of the four cortex sections. / Finally, the accuracy and limitation of this smoothing method is tested using some simulated examples.

No description available.

We introduce the class AUMD of Banach spaces X for which X-valued analytic martingales converge unconditionally. We shew that various possible definitions of this class are equivalent by methods of martingale decomposition. We shew that such X have finite cotype and are q-complex uniformly convex in the sense of Garling. Using multipliers we shew that analytic martingales valued in L¹ converge unconditionally and that AUMD spaces have the analytic Radon-Nikodym property. We shew that X has the AUMD property if and only if strong Hbrmander-Mihlin multipliers are bounded on the Hardy space H¹_x(T). We achieve this by representing multipliers as martingale transforms. It is shewn that if X is in AUMD and is of cotype two then X has the Paley Theorem property. Using an isomorphism result we shew that if A is an injective operator system on a separable Hilbert space and P a completely bounded projection on A, then either PA or (I-P)A is completely boundedly isomorphic to A. The finite-dimensional version of this result is deduced from Ramsey's Theorem. It is shewn that B(e² is primary. It is shewn that weakly compact homomorphisms T from the 2 disc algebra into B(e² are necessarily compact. An explicit form for such T is obtained using spectral projections and it is deduced that such T are absolutely summing.

Bitter taste is one of the five basic taste modalities, and is mediated by 25 bitter taste receptors (T2Rs) in humans. How these few receptors recognize a wide range of structurally diverse bitter compounds is not known. To address this question, structural and functional studies on T2Rs are necessary. Quinine is a natural alkaloid and one of the most intense bitter tasting compounds. Previously it was shown that quinine activates T2R4, however, whether T2R4 has only one binding site for quinine, and the amino acids on the receptor involved in binding to quinine remain to be determined. In this study, the ligand binding pocket on T2R4 for quinine was characterized using a combination of approaches. These included molecular model guided site-directed mutagenesis, characterization of the expression of the mutants by flow cytometry, and functional characterization by cell based calcium imaging. Twelve mutations were made in T2R4 and their expression and function were characterized. Results show that the ligand binding pocket of T2R4 for quinine is situated on the extracellular side, and is formed by the residues present on the transmembrane regions TM3, TM4, and extracellular loop regions ECL2 and TM6-ECL3-TM7 interface. Further, this study identified the following amino acids : A90, F91, Y155 N173, T174, Y258 and K270 to play an important role in quinine binding to T2R4. The detailed study of residues interacting with ligand will help in understanding how various ligands interact with T2Rs, and facilitate the pharmacological characterization of potent antagonists or bitter taste blockers. The characterization of novel ligands, including bitter taste blockers will help in dissecting the signaling mechanism(s) of T2Rs, and help in the development of novel therapeutic tools for the food and drug industry.

Given a compensated Poisson process $(X_t)_{t \geq 0}$ based on $(\Omega, \mathcal{F}, \mathbb{P})$, the Wiener-Poisson isomorphism $\mathcal{W} : \mathfrak{F}_+(L^2 (\mathbb{R}_+)) \to L^2 (\Omega, \mathcal{F}, \mathbb{P})$ is constructed. We restrict the isomorphism to $\mathfrak{F}_+(L^2 [0,1])$ and prove some novel properties of the Poisson exponentials $\mathcal{E}(f) := \mathcal{W}(e(f))$. A new proof of the result $\Lambda_t + A_t + A^{\dagger}_t = \mathcal{W}^{-1}\widehat{X_t} \mathcal{W}$ is also given. The analogous results for $\mathfrak{F}_+(L^2 (\mathbb{R}_+))$ are briefly mentioned. The concept of a compensated Poisson process over $\mathbb{R}_+$ is generalised to any measure space $(M, \mathcal{M}, \mu)$ as an isometry $I : L^2(M, \mathcal{M}, \mu) \to L^2 (\Omega,\mathcal{F}, \mathbb{P})$ satisfying certain properties. For such a generalised Poisson process we recall the construction of the generalised Wiener-Poisson isomorphism, $\mathcal{W}_I : \mathfrak{F}_+(L^2(M)) \to L^2 (\Omega, \mathcal{F}, \mathbb{P})$, using Charlier polynomials. Two alternative constructions of $\mathcal{W}_I$ are also provided, the first using exponential vectors and then deducing the connection with Charlier polynomials, and the second using the theory of reproducing kernel Hilbert spaces. Given any measure space $(M, \mathcal{M}, \mu)$, we construct a canonical generalised Poisson process $I : L^2 (M, \mathcal{M}, \mu) \to L^2(\Delta, \mathcal{B}, \mathbb{P})$, where $\Delta$ is the maximal ideal space, with $\mathcal{B}$ the completion of its Borel $\sigma$-field with respect to $\mathbb{P}$, of a $C^*$-algebra $\mathcal{A} \subseteq \mathfrak{B}(\mathfrak{F}_+(L^2(M)))$. The Gelfand transform $\mathcal{A} \to \mathfrak{B}(L^2(\Delta))$ is unitarily implemented by the Wiener-Poisson isomorphism $\mathcal{W}_I: \mathfrak{F}_+(L^2(M)) \to L^2(\Delta)$. This construction only uses operator algebra theory and makes no a priori use of Poisson measures. A new Fock space proof of the quantum Ito formula for $(\Lambda_t + A_t + A^{\dagger}_t)_{0 \leq t \leq 1}$ is given. If $(F_{\ \! \! t})_{0 \leq t \leq 1}$ is a real, bounded, predictable process with respect to a compensated Poisson process $(X_t)_{0 \leq t \leq 1}$, we show that if $M_t = \int_0^t F_s dX_s$, then on $\mathsf{E}_{\mathrm{lb}} := \mathrm{linsp} \{ e(f) : f \in L^2_{\mathrm{lb}}[0,1] \}$, $\mathcal{W}^{-1} \widehat{M_t} \mathcal{W} = \int_0^t \mathcal{W}^{-1} \widehat{F_s} \mathcal{W} (d\Lambda_s + dA_s + dA^{\dagger}_s),$ and that $(\mathcal{W}^{-1} \widehat{M_t} \mathcal{W})_{0 \leq t \leq 1}$ is an essentially self-adjoint quantum semimartingale. We prove, using the classical Ito formula, that if $(J_t)_{0 \leq t \leq 1}$ is a regular self-adjoint quantum semimartingale, then $(\mathcal{W} \widehat{M_t} \mathcal{W}^{-1} + J_t)_{0 \leq t \leq 1}$ is an essentially self-adjoint quantum semimartingale satisfying the quantum Duhamel formula, and hence the quantum Ito formula. The equivalent result for the sum of a Brownian and Poisson martingale, provided that the sum is essentially self-adjoint with core $\mathsf{E}_{\mathrm{lb}}$, is also proved.

No description available.

The following thesis is divided into two main parts. In the first part we study the problem of characterizing algebras of functions living on analytic varieties. Specifically, we consider the restrictions M_V of the multiplier algebra M of Drury-Arveson space to a holomorphic subvariety V of the unit ball as well as the algebras A_V of continuous multipliers under the same restriction. We find that M_V is completely isometrically isomorphic to cM_W if and only if W is the image of V under a biholomorphic automorphism of the ball. In this case, the isomorphism is unitarily implemented. Furthermore, when V and W are homogeneous varieties then A_V is isometrically isomorphic to A_W if and only if the defining polynomial relations are the same up to a change of variables. The problem of characterizing when two such algebras are (algebraically) isomorphic is also studied. In the continuous homogeneous case, two algebras are isomorphic if and only if they are similar. However, in the multiplier algebra case the problem is much harder and several examples will be given where no such characterization is possible. In the second part we study the triangular subalgebras of UHF algebras which provide new examples of algebras with the Dirichlet property and the Ando property. This in turn allows us to describe the semicrossed product by an isometric automorphism. We also study the isometric automorphism group of these algebras and prove that it decomposes into the semidirect product of an abelian group by a torsion free group. Various other structure results are proven as well.