Alan A. Sola

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Disematostoma colpidioides, until now, Wenrichia colpidioides, is a reniform ciliate with a strong torsion at the equatorial plane. The nuclear apparatus consists of a long macronucleus and a spherical micronucleus. The oral infraciliature is made up by a paroral kinety and three peniculi with 4,4, and 3 rows of kinetosomes, respectively. At the right slope(More)
Most of the so-called "lower hypostomes", nassophorean ciliates in the most recent classifications of the phylum Ciliophora, have been little studied in modern times (e.g., employing methods of silver impregnation, a technique widely considered indispensable in comparative taxonomic work on these protists today). In this paper, we present descriptions of(More)
Abstract. We consider a variation of the standard HastingsLevitov model HL(0), in which growth is anisotropic. Two natural scaling limits are established and we give precise descriptions of the effects of the anisotropy. We show that the limit shapes can be realised as Loewner hulls and that the evolution of harmonic measure on the cluster boundary can be(More)
We give a complete characterization of polynomials in two complex variables that are cyclic with respect to the coordinate shifts acting on Dirichlet-type spaces in the bidisk, which include the Hardy space and the Dirichlet space of the bidisk. The cyclicity of a polynomial depends on both the size and nature of the zero set of the polynomial on the(More)
The reproducing kernel function of a weighted Bergman space over domains in C is known explicitly in only a small number of instances. Here, we introduce a process of orthogonal norm expansion along a subvariety of codimension 1, which also leads to a series expansion of the reproducing kernel in terms of reproducing kernels defined on the subvariety. The(More)
We study connections between orthogonal polynomials, reproducing kernel functions, and polynomials p minimizing Dirichlet-type norms ‖pf − 1‖α for a given function f . For α ∈ [0, 1] (which includes the Hardy and Dirichlet spaces of the disk) and general f , we show that such extremal polynomials are non-vanishing in the closed unit disk. For negative α,(More)
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