75 research outputs found

    A tale of two tables

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    Células cebadas en pulmón y nervio periférico en la intoxicación crónica con karwinskia humboldtiana en rata wistar: estudios histológico e histoquímico = Lung and peripheral nerve mast cells in chronic intoxication with karwinskia humboldtiana in wistar rat: histological and histochemical Studies

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    Karwinskia humboldtiana (Kh) es un arbusto venenoso responsable de numerosos casos de intoxicación accidental en humanos. En estudios previos en nuestro laboratorio reportamos un incremento de células cebadas en nervio periférico (NP) durante la intoxicación con Kh, este hallazgo no ha sido reportado previamente en otros órganos durante esta intoxicación por lo que en el presente estudio buscamos la presencia de estas células en otros órganos, además de distinguir subpoblaciones de células cebadas mediante reacciones histoquímicas para la identificación de los gránulos de secreción. El objetivo de este estudio fue evaluar la presencia de células cebadas en órganos distintos al NP y diferenciar histoquímicamente la composición de sus gránulos. Se utilizaron 32 ratas Wistar, se dividieron en cuatro grupos (n= 8) en donde 5 ratas de cada grupo fueron intoxicadas y 3 fueron control no intoxicadas. A las ratas intoxicadas se les administraron por vía oral 3,5 g/kg del fruto seco y molido de Kh fraccionados en 5 dosis de 1,5; 0,5, 0,5; 0,5 y 0,5 g/kg los días 0, 3, 7, 10 y 14 respectivamente. Las ratas control solo recibieron agua. Cada grupo fue sacrificado a diferentes tiempos según la evolución de la parálisis. Se obtuvieron muestras de Hígado, Riñón, Pulmón y SNP, se procesaron hasta obtener bloques de parafina, se obtuvieron cortes y se tiñeron con azul de toluidina, PAS, Azul alciano/PAS y Azul alciano/Safranina. Se identificó la presencia de células cebadas en NP y pulmón con la tinción de azul de toluidina y se realizo un estudio morfométrico observando un incremento progresivo del número de células cebadas por grupo así como variaciones histoquímicas en sus gránulos en cada etapa y órgano analizado, lo que sugiere la participación de las células cebadas y sus secreciones en cada una de las etapas de la intoxicación crónica con el fruto maduro de Kh

    Kinetic energy bounds for particles confined in spherically-symmetric traps with non-standard dimensions

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    The kinetic energy of non-relativistic single-particle systems with arbitrary D-dimensional central potentials is found to be bounded from below by means of the orbital hyperangular quantum number, the dimensionality and some radial and logarithmic expectation values of the form langrkrang and langrk (ln r)mrang. Beyond the intrinsic physico-mathematical interest of this problem, we want to contribute to the current development of the theory of independent particles confined in spherically symmetric traps with non-standard dimensions. The latter has been motivated by the recent experimental achievements of the evaporative cooling of dilute (i.e. almost non-interacting) fermions in magnetic traps.We are very grateful for partial support from Junta de Andalucía (under the grants FQM-0207 and FQM-481), Ministerio de Educación y Ciencia (under the project FIS2005-00973), and the European Research Network NeCCA (under the project INTAS-03-51-6637). RGF acknowledges the support of Junta de Andalucía under the program of Retorno de Investigadores a Centros de Investigación Andaluces, and PSM the support of Ministerio de Educación y Ciencia under the program FPU

    Mathematical Aspects of the Periodic Law

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    We review different studies of the Periodic Law and the set of chemical elements from a mathematical point of view. This discussion covers the first attempts made in the 19th century up to the present day. Mathematics employed to study the periodic system includes number theory, information theory, order theory, set theory and topology. Each theory used shows that it is possible to provide the Periodic Law with a mathematical structure. We also show that it is possible to study the chemical elements taking advantage of their phenomenological properties, and that it is not always necessary to reduce the concept of chemical elements to the quantum atomic concept to be able to find interpretations for the Periodic Law. Finally, a connection is noted between the lengths of the periods of the Periodic Law and the philosophical Pythagorean doctrine.Comment: 20 pages, PDF fil

    A Unified Near Infrared Spectral Classification Scheme for T Dwarfs

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    A revised near infrared classification scheme for T dwarfs is presented, based on and superseding prior schemes developed by Burgasser et al. and Geballe et al., and defined following the precepts of the MK Process. Drawing from two large spectroscopic libraries of T dwarfs identified largely in the Sloan Digital Sky Survey and the Two Micron All Sky Survey, nine primary spectral standards and five alternate standards spanning spectral types T0 to T8 are identified that match criteria of spectral character, brightness, absence of a resolved companion and accessibility from both northern and southern hemispheres. The classification of T dwarfs is formally made by the direct comparison of near infrared spectral data of equivalent resolution to the spectra of these standards. Alternately, we have redefined five key spectral indices measuring the strengths of the major H2_2O and CH4_4 bands in the 1-2.5 micron region that may be used as a proxy to direct spectral comparison. Two methods of determining T spectral type using these indices are outlined and yield equivalent results. These classifications are also equivalent to those from prior schemes, implying that no revision of existing spectral type trends is required. The one-dimensional scheme presented here provides a first step toward the observational characterization of the lowest luminosity brown dwarfs currently known. Future extensions to incorporate spectral variations arising from differences in photospheric dust content, gravity and metallicity are briefly discussed. A compendium of all currently known T dwarfs with updated classifications is presented.Comment: 52 pages, 11 figures; accepted for publication to Ap

    Defining a General Structure of Four Inferential Processes by Means of Four Pairs of Choices Concerning Two Basic Dichotomies

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    In previous papers I have characterized four ways of reasoning in Peirce’s philosophy, and four ways of reasoning in Computability Theory. I have established their correspondence on the basis of the four pairs of choices regarding two dichotomies, respectively the dichotomy between two kinds of Mathematics and the dichotomy between two kinds of Logic. In the present paper I introduce four principles of reasoning in theoretical Physics and I interpret also them by means of the four pairs of choices regarding the above two dichotomies. I show that there exists a meaningful correspondence among the previous three fourfold sets of elements. This convergence of the characteristic ways of reasoning within three very different fields of research - Peirce’s philosophy, Computability theory and physical theories - suggests that there exists a general-purpose structure of four ways of reasoning. This structure is recognized as applied by Mendeleev when he built his periodic table. Moreover, it is shown that a chemist-, applies all the above ways of reasoning at the same time. Peirce’s professional practice as a chemist applying at the same time this variety of reasoning explains his stubborn research into the variety of the possible inferences

    On the Question of the Psychology of Scientific Creativity

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