试谈禾本科植物生殖器官主要性状的分类价值及其适用等级

生殖器官性状一直是禾本科植物分类的主要依据，但由于各个性状所附实体的形态特点，着生位置，发育程度和环境饰变的差异，其分类价值是不尽相同的，为了克服该类性状使用上的种种弊病，本文特对主要宏观性状的分类价值进行了评述，总结了它们在应用中各自适宜的等级范围，其中象花序的类型，小穗的着生，小花和果实的形状等价值较高，通常适合于族级以上烘群的划分，花序的形状，小穗的排列，果料的类型等价值偏低，通常 适合于属，种级类群的区分，而花序 的长短与粗细，小穗轴，内稃等价值较低，通常适合于种级或种级之下类群的鉴分。

层序地层分析在非油气领域的应用进展及前景评述

层序地层分析已在油气勘探中发挥重要作用。相比而言，其在非油气领域的应用尚处于起步阶段。文章论述了层序地层分析的基本内容及其在非油气领域的应用进展；从油气与非油气矿床成矿、富集规律的相似性和两者的共生性，以及层序界面、沉积体系域与成矿基本要素和条件的耦合性．评述了层序地层分析在非油气领域的应用具有广阔的前景；同时又针对油气与非油气矿床在成矿方面的差异性和海、陆相层序地层的差异性，指出了层序地层分析应用于非油气领域时应注意或需研究的一些问题.

An efficient approach to modify the catalyst activity for the hydrogenation of nitrobenzene

The addition of a suitable amount of PPh3 to PdCl2 or PdCl2(PhCN)(2) in situ can considerably increase the catalytic activity in the hydrogenation of nitrobenzene, while the catalytic activities of PdCl2 (reduced)+PPh3, PdCl2(PPh3)(2) and Pd(PPh3)(4) are very poor. The poisoning of catalyst by mercury indicates that the catalytically active species are composed of Pd(0) colloidal particles. Transmission electron micrographs show that the size of nanometric Pd(0) particles of PdCl2 with PPh3 added in situ is smaller than that of PhCl2(PPh3) or PdCl2 (reduced)+PPh3. A synergic effect of bimetallic catalysts such as PdCl2+nPPh(3)+NiCl2 (n= 0.5, 1) and PdCl2(PhCN)(2)+PPh3+FeCl3 gives rise to a further increase in the catalytic activity.

Birkhoff normal forms for Fourier integral operators II

Iantchenko, A.; Sj?strand, J., (2001) 'Birkhoff normal forms for Fourier integral operators II', American Journal of Mathematics 124(4) pp.817-850 RAE2008

Capacitación, asistencia técnica y seguimiento en la intervención de los procesos técnicos y tecnológicos de ripiado, secado, tinturado, majado, estufado, blanqueado de sombreros y otras artesanías en paja toquilla. Región Occidente, departamento de Nariño.

35 hojas : ilustraciones.

An immunoglobulin C kappa-reactive single chain antibody fusion protein induces tolerance through receptor editing in a normal polyclonal immune system.

Understanding immune tolerance mechanisms is a major goal of immunology research, but mechanistic studies have generally required the use of mouse models carrying untargeted or targeted antigen receptor transgenes, which distort lymphocyte development and therefore preclude analysis of a truly normal immune system. Here we demonstrate an advance in in vivo analysis of immune tolerance that overcomes these shortcomings. We show that custom superantigens generated by single chain antibody technology permit the study of tolerance in a normal, polyclonal immune system. In the present study we generated a membrane-tethered anti-Igkappa-reactive single chain antibody chimeric gene and expressed it as a transgene in mice. B cell tolerance was directly characterized in the transgenic mice and in radiation bone marrow chimeras in which ligand-bearing mice served as recipients of nontransgenic cells. We find that the ubiquitously expressed, Igkappa-reactive ligand induces efficient B cell tolerance primarily or exclusively by receptor editing. We also demonstrate the unique advantages of our model in the genetic and cellular analysis of immune tolerance.

Accurate ground-state potential energy surfaces of the C2H2–Kr and C2H2–Xe van der Waals complexes

Accurate ab initio intermolecular potential energy surfaces (IPES) have been obtained for the first time for the ground electronic state of the C 2H2-Kr and C2H2-Xe van der Waals complexes. Extensive tests, including complete basis set and all-electron scalar relativistic results, support their calculation at the CCSD(T) level of theory, using small-core relativistic pseudopotentials for the rare-gas atoms and aug-cc-pVQZ basis sets extended with a set of 3s3p2d1f1g mid-bond functions. All results are corrected for the basis set superposition error. The importance of the scalar relativistic and rare-gas outer-core (n.1)d correlation effects is investigated. The calculated IPES, adjusted to analytical functions, are characterized by global minima corresponding to skew T-shaped geometries, in which the Jacobi vector positioning the rare-gas atom with respect to the center of mass of the C2H2 moiety corresponds to distances of 4.064 and 4.229Å, and angles of 65.22° and 68.67° for C 2H2-Kr and C2H2-Xe, respectively. The interaction energy of both complexes is estimated to be -151.88 (1.817 kJ mol-1) and -182.76 cm-1 (2.186 kJ mol-1), respectively. The evolution of the topology of the IPES as a function of the rare-gas atom, from He to Xe, is also discussed. © 2012 Taylor and Francis.

La periodicidad en el sistema didáctico: una articulación a la luz de la socioepistemología

Este trabajo aporta elementos que robustecen la socioepistemología propuesta sobre lo periódico en la que la predicción es la práctica asociada a la construcción del conocimiento matemático. Además de trabajar en un contexto de funciones periódicas distancia-tiempo, se abordan otros contextos como las sucesiones periódicas de números y de figuras.

Los usos sociales de la matemática en las ciencias prácticas de la cultura maya: un estudio socioepistemológico

El presente trabajo plantea el estudio del conocimiento matemático de la cultura maya desde la aproximación socioepistemológica, ya que se aporta una visión diferente de las que suelen abordarse en la literatura: antropológica o etnográfica entre otras. Se plantea el estudio de prácticas sociales que se encuentran en la cultura maya y que son a la vez generadoras de conocimiento matemático.