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Abstract  

Sodium titanium germanate with a semicrystalline framework (STG) of the formula Na3H(TiO)3(GeO)(GeO4)3·7H2O was synthesized under mild hydrothermal conditions and its proton form, H4(TiO)3(GeO)(GeO4)3·8H2O (STG-H), was prepared by acid treatment of the sodium compound. The STG was characterized by elemental analysis, TGA, FT-IR, and X-ray powder diffraction. A comparative ion exchange examination of the STG-H towards alkali and alkaline earth metals in a broad pH and concentration range was carried out. It was found that the STG is a moderately weak cation exchanger, possessing high ion exchange capacity (up to 4.0 meq/g) and showing preference for heavy alkali and alkaline earth metals. The STG selectivity towards Cs+ and Sr2+ ions in the presence of competitive metal ions and certain organic compounds was also studied. The data obtained suggest that the sodium titanium germanate is a more selective exchanger for Sr2+ ion than its titanium silicate analogue, K3H(TiO)4(SiO4)3·4H2O.

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Estudios Sobre Rubiáceas Mexicanas XV

Una espécie nueva del género Guettarda de Chiapas

Acta Botanica Hungarica
Authors: A. Borhidi and A. Reyes-García

A new species of the genus Guettarda (Guettardeae, Rubiaceae) from Chiapas, South Mexico, was collected by the second author. Guettarda quadrifida sp. n. is closely related to G. subcapitata C. M. Taylor, but differs from it by having short 4-lobed inflorescence axes and flowers occulted by long bracteoles.

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Estudios Sobre Rubiáceas Mexicanas XI

Revisión del género Csapodya Borhidi (Rondeletieae), endémico de Chiapas con tres especies

Acta Botanica Hungarica
Authors: A. Borhidi and A. Reyes-García

From the excellent collection of Albert Reyes-García made in Sierra Morena (southwestern part of the Sierra Madre de Chiapas) appeared some plants of high interest; among them two beautiful new species, belonging to the recently described Csapodya genus considered formerly as a monotypic endemic one. The present paper contains the description of the two new species named Csapodya challengeri and C. sousae , and the amplified description of the genus.

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The new Psychotria species belongs to the panamensis-mexiae complex with its large long deciduous ferrugineous terminal stipules, but differs from them by having shorter inflorescence, 2–3 times larger flowers, smaller leaves and less numerous secondary nerves. It is of allopatric distribution being endemic to Jalisco state, while the area of P. mexiae Standl. extends from Veracruz to Costa Rica and the populations of P. panamensis Standl. are found from Veracruz to Colombia.

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Estudios Sobre Rubiáceas Mexicanas XXIV

Contribuciones al conocimiento de Randia lanuginosa Borhidi et I. García-González

Acta Botanica Hungarica
Authors: A. Borhidi and I. García-González

Randia lanuginosa was described in 2006 based on a fruited specimen collected by the experts of INEGI in Jalisco. Two years later, several unidentified specimens arrived to the MEXU from the collection of the Estación de Investigaciones Biológicas de la UNAM in Chamela. Several flowering specimens of this collection permitted to the authors to complete the original description of this notable species endemic to state Jalisco.

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Estudios sobre Rubiáceas Mexicanas, X.

Dos espécies nuevas de Rubiáceas en el herbario de Inegi (Aguascalientes), México

Acta Botanica Hungarica
Authors: A. Borhidi and I. García Gonzalez

The valuable plant collection of INEGI has not been considered according to its merit. A preliminary study of the Rubiaceae family led to the discovery of two new species: Bouvardia castilloi and Randia lanuginosa.

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Abstract  

We characterize the supports of the measures having quadrature formulae with similar exactness as Gauss’ theorem. Indeed we obtain the supports of the measures from which an m-point quadrature formula can be obtained such that it exactly integrates functions in the space ℙmk,mk[
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage{bbm} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\bar z$$ \end{document}
, z]. We also give a method for obtaining the nodes and the quadrature coefficients in all the cases and, as a consequence, we solve the same problem in the space of trigonometric polynomials.
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Abstract  

The Mössbauer parameters of anhydrous monoclinic tin/II/ phosphate, Sn3/PO4/2, are reported and briefly discussed. The results agree with the interactions expected from the crystalline structure but differ from previously reported data.

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