1,248 research outputs found

    Techniques for augmenting the visualisation of dynamic raster surfaces

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    Despite their aesthetic appeal and condensed nature, dynamic raster surface representations such as a temporal series of a landform and an attribute series of a socio-economic attribute of an area, are often criticised for the lack of an effective information delivery and interactivity.In this work, we readdress some of the earlier raised reasons for these limitations -information-laden quality of surface datasets, lack of spatial and temporal continuity in the original data, and a limited scope for a real-time interactivity. We demonstrate with examples that the use of four techniques namely the re-expression of the surfaces as a framework of morphometric features, spatial generalisation, morphing, graphic lag and brushing can augment the visualisation of dynamic raster surfaces in temporal and attribute series

    Regularization matrices for discrete ill-posed problems in several space-dimensions

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    Many applications in science and engineering require the solution of large linear discrete ill-posed problems that are obtained by the discretization of a Fredholm integral equation of the first kind in several space dimensions. The matrix that defines these problems is very ill conditioned and generally numerically singular, and the right-hand side, which represents measured data, is typically contaminated by measurement error. Straightforward solution of these problems is generally not meaningful due to severe error propagation. Tikhonov regularization seeks to alleviate this difficulty by replacing the given linear discrete ill-posed problem by a penalized least-squares problem, whose solution is less sensitive to the error in the right-hand side and to roundoff errors introduced during the computations. This paper discusses the construction of penalty terms that are determined by solving a matrix nearness problem. These penalty terms allow partial transformation to standard form of Tikhonov regularization problems that stem from the discretization of integral equations on a cube in several space dimensions

    Biophysical Characterization Of A Proline Mutant Of Neural Cadherin

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    Cadherins are calcium dependent glycoproteins whose homophilic interactions mediate cell-cell adhesion in solid tissues. They are comprised of an extracellular region, a transmembrane region and a cytoplasmic region. The extracellular region plays a critical role in cadherin-mediated cell adhesion, and has five tandemly repeated ectodomains (ec1-ec5), with three calcium binding sites situated in each interface between the domains. Dimerization of cadherin occurs through formation of adhesive interactions between extracellular domains of cadherins from neighboring cells. Adhesive interaction occurs at the interfaces of ec1 domains of two molecules originating from different cell surfaces. Dimerization is critically dependent on the binding of calcium. Neural and epithelial cadherin (ncad and ecad) are very similar in sequence comparison, but differ in kinetics of dimer assembly and dimer affinity in the presence or absence of calcium. The single most obvious difference in the strand swapped interface is a proline in ncad and a glutamate in ecad in position 16. Our hypothesis is that the slow kinetics of dimer disassembly of ncad is due to the steric restrictions of proline in position 16 of ncad. The purpose of this research is to mutate the proline, in position 16 to alanine (p16a), in ncad to decrease the steric hindrance and study the effects of the mutation. Stability studies assess the effect the mutation has on the folding properties of the protein. Calcium binding experiments demonstrate whether the mutation affects the binding affinity of calcium. From the results, p16a lowers the stability of the protein, ca2+ binding affinity, and dimerization kinetics of ncad
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