Environmental gradients caused by hydrological changes, whether natural or maninduced, affect the planktonic taxonomic and functional composition in shallow water ecosystems. In this sense, our aim was to find out the main variables or variable ratios that are the driving forces of the major phytoplankton taxonomic groups in Mediterranean coastal lagoons. For this purpose, 11 waterbodies were c...

There are two major formulations of image alignment using gradient descent. The first estimates an additive increment to the parameters (the additive approach), the second an incremental warp (the compositional approach). We first prove that these two formulations are equivalent. A very efficient algorithm was recently proposed by Hager and Belhumeur using the additive approach that unfortunate...

Genomic DNA sequences display compositional heterogeneity on many scales. In this paper we analyzed tendencies and anomalies in the occurence of mono, di and trinucleotides in structural regions of plant genes. Representation of these trends as a function of position along genic sequences highlighted compositional features peculiar of either monocots or eudicots that were remarkably uniform wit...

Uphill diffusion, the diffusion of a component up its own concentration gradient, has often been observed in experimental studies of diffusion i synthetic multicomponent systems and natural silicate melts. To apply experimental data to natural processes, it is necessary toquantify this effect. A modified effective binary diffusion model is developed in this paper. The diffusive flux of a compon...

Abstract: A recently proposed fast image alignment algorithm is the inverse compositional algorithm based on LucasKanade. In this paper, we present an overview of different brightness and gradient constraints used with the inverse compositional algorithm. We also propose an efficient and robust data constraint for the estimation of global motion from image sequences. The constraint combines bri...

Phenomena with a constrained sample space appear frequently in practice. This is the case, for example, with strictly positive data, or with compositional data, such as percentages or proportions. If the natural measure of difference is not the absolute one, simple algebraic properties show that it is more convenient to work with a geometry different from the usual Euclidean geometry in real sp...