E-Connectedness, Finite Approximations, Shape Theory and Coarse Graining in Hyperspaces

We use upper semifinite hyperspaces of compacta to describe "-connectedness and to compute homology from finite approximations. We find another connection between "- connectedness and the so called Shape Theory. We construct a geodesically complete R-tree, by means of "-components at different resolutions, whose behavior at infinite captures the topological structure of the space of components of a given compact metric space. We also construct inverse sequences of finite spaces using internal finite approximations of compact metric spaces. These sequences can be converted into inverse sequences of polyhedra and simplicial maps by means of what we call the Alexandroff-McCord correspondence. This correspondence allows us to relate upper semifinite hyperspaces of finite approximation with the Vietoris-Rips complexes of such approximations at different resolutions. Two motivating examples are included in the introduction. We propose this procedure as a different mathematical foundation for problems on data analysis. This process is intrinsically related to the methodology of shape theory. Finally this paper reinforces Robins’s idea of using methods from shape theory to compute homology from finite approximations

Ultrametric spaces, valued and semivalued groups arising from the theory of shape

In this paper we construct many generalizad ultrametrics in the sets of shape morphisms between topological spaes. We recognize a topology in these sets which is independen on the shape representation of the spaces. We construct valuations an semivaluations on groups of shape equivalences and on n-th shape groups. We also connect shape theory, for arbitrary topological spaces, with the algebraic theory of generalized ultrametric spaces developed by S. Priess-Crampe and P. Ribenboim among other authors

El problema de la intersección de ANR’s de Borsuk y métricas en el hiperespacio del cubo de Hilbert

En este artículo relacionamos dos problemas abiertos en Homotopía y Teoría de la Forma planteados por Borsuk. Demostramos que la respuesta a, al menos,uno de ellos es negativa, y obtenemos algunas consecuencias

Role of magnetic anisotropy on the magnetic properties of Ni nanoclusters embedded in a ZnO matrix

We have investigated the magnetic properties of Ni nanoaggregates produced by ion implantation in ZnO single crystals. Several deviations from classical models usually adopted to describe the magnetic properties of nanoparticle systems were found. The strain between host and Ni nanoaggregates induces a magnetic anisotropy with a preferred direction. We show that these anisotropy effects can be misinterpreted as a ferromagnetic or antiferromagnetic coupling among the nanoaggregates similar to that of an oriented, interacting nanocrystal ensemble

Thermal behavior of hard-axis magnetization in noninteracting particles with uniaxial anisotropy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Experimental evidence is presented to support predictions made by an analytical model describing the temperature-dependent behavior of an assembly of noninteracting magnetic nanoparticles with uniaxial anisotropy under an external field. When the applied field is smaller than the anisotropy field of the particles and is oriented perpendicular to the easy axis, a maximum of the magnetization occurs at finite temperature. The theory shows good agreement with measurements of an array of CoCrPt nanoislands with uniaxial anisotropy. Deviations are discussed taking into account the thermal dependencies of the saturation magnetization and the anisotropy of the magnetic material.9520PIIC-DGIP-USMFondecyt Chile [1070224]Millennium Science Initiative ChileFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CONICYTNational Science Foundation [DMR 02-13282]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fondecyt Chile [1070224]National Science Foundation [DMR 02-13282

efecto de la mezcla ensilada de penisetum purpureum y tithonia diversifolia sobre la fermentacion ruminal in vitro y su emision de metano en el sistema rusitec

Los ganaderos del trópico tradicionalmente han usado dietas con base en gramineas con limitaciones nutricionales. Tal deficiencia, exigen el suplemento con especies leñosas de alta calidad proteica. Se evaluó el patrón de fermentación ruminal y la liberación de metano en un sistema de Simulación del Rumen (RUSITEC) utilizando como ensilaje control Pennisetum prurpureum al 100% (T1) versus ensilaje de una mezcla (67% Pennisetum prurpureum / 33% Tithonia diversifolia ) enriquecido, o no, con aditivos: (T2) sin aditivo; (T3) Lactobacillus paracasei T735; (T4) inóculo comercial SIL-ALL®4x4. Se hizo un suministro diario de MS para mantener constante el flujo en el sistema y evaluar los cuatro tratamientos, durante un periodo de ocho días. Los datos se analizaron mediante un diseño completamente al azar. No hubo efecto de los tratamientos (T2, T3 y T4) versus control (T1) en la concentración de NH4-N (p 0.05). La disminución en la emisión de CH4 por gramo de MS en ensilajes (PP/TD), posiblemente se explica por una menor degradación de la fibra y sugiere que habrá menos emisiones de CH4 por unidad de proteína comestible producida. Sin embargo, la cantidad total de metano que se libera no fue diferente estadísticamente

The correlation of RNase A enzymatic activity with the changes in the distance between Nepsilon2-His12 and N delta1-His119 upon addition of stabilizing and destabilizing salts.

The effect of stabilizing and destabilizing salts on the catalytic behavior of ribonuclease A (RNase A) was investigated at pH 7.5 and 25 degrees C, using spectrophotometric, viscometric and molecular dynamic methods. The changes in the distance between N(epsilon2) of His(12) and N(delta1) of His(119) at the catalytic center of RNase A upon the addition of sodium sulfate, sodium hydrogen sulfate and sodium thiocyanate were evaluated by molecular dynamic methods. The compactness and expansion in terms of Stokes radius of RNase A upon the addition of sulfate ions as kosmotropic salts, and thiocyanate ion as a chaotropic salt, were estimated by viscometric measurements. Enzyme activity was measured using cytidine 2', 3'-cyclic monophosphate as a substrate. The results from the measurements of distances between N(epsilon2) of His(12) and N(delta1) of His(119) and Stokes radius suggest (i) that the presence of sulfate ions decreases the distance between the catalytic His residues and increases the globular compactness, and (ii) that there is an expansion of the enzyme surface as well as elongation of the catalytic center in the presence of thiocyanate ion. These findings are in agreement with activity measurements