Estudio sobre la capacidad coordinante de Bases de Schiff derivadas de orto- y meta-fenilendiaminas

Estudios de la capacidad coordinante de bases de Schiff derivadas de orto- y meta-diaminas aromáticas: 1. en DMSO-agua 80:20 P/P, se ha estudiado la capacidad coordinante de bases de Schiff frente a diferentes cationes metálicos mediante la técnica potenciométrica, determinando las correspondientes constantes de estabilidad de las especies complejas formadas: a) las bases orto forman complejos monómeros muy estables, lo que es confirmado al determinar por difracción de rayos X las estructuras cristalinas de los complejos fe(sal-o-phen) c1 y ni(sal-3,4-toluen); b) las bases meta forman especies monómeras, especies dímeras más estables, especies con exceso de ligando y especies con exceso de metal; la formacion de las especies dimeras se ha confirmado tambien con la determinacion estructural del complejo co2(sal-m-o-phen)2. los complejos dímeros de co(II), ni(II) y cu(II) presentan débiles interacciones antiferromagnéticas. 2. los complejos con bases orto del tipo (fe(Bs.)imd2) y, con grupo coordinante n4o2 son susceptibles de exhibir variedad de comportamientos magnéticos: alto spin, bajo spin y transición de spin. Se presentan ejemplos de los tres casos y se determina la estructura cristalina de tres complejos

Hydroxylated phosphines as ligands for chalcogenide clusters: self assembly, transformations and stabilization

This contribution is a documentation of recent advances in the chemistry of chalcogenide polynuclear transition metal complexes coordinated with mono- and di-phosphines functionalized with hydroxo groups. A survey of complexes containing tris(hydroxymethyl)phosphine (THP) is presented. The influence of the alkyl chain in bidentate phosphines, bearing the P–(CH2)x–OH arms, is also analyzed. Finally, isolation and structure elucidation of the complexes with HP(OH)2, P(OH)3, As(OH)3, PhP(OH)2, stabilized by coordination to Ni(0) and Pd(0) centers embedded into chalcogenide clusters, is discussed

Combined kinetic and DFT studies on the stabilization of the pyramidal form of H3PO2 at the heterometal site of [Mo3M’S4(H2O)10]4+ clusters (M’= Pd, Ni)

Kinetic and DFT studies have been carried out on the reaction of the [Mo3M’S4(H2O)10]4+ clusters (M’= Pd, Ni) with H3PO2 to form the [Mo3M’(pyr-H3PO2)S4(H2O)9]4+ complexes, in which the rare pyramidal form of H3PO2 is stabilized by coordination to the M’ site of the clusters. The reaction proceeds with biphasic kinetics, both steps showing a first order dependence with respect to H3PO2. These results are interpreted in terms of a mechanism that involves an initial substitution step in which one tetrahedral H3PO2 molecule coordinates to M’ through the oxygen atom of the P=O bond, followed by a second step that consists in tautomerization of coordinated H3PO2 assisted by a second H3PO2 molecule. DFT studies have been carried out to obtain information on the details of both kinetic steps, the major finding being that the role of the additional H3PO2 molecule in the second step consists in catalysing a hydrogen shift from phosphorus to oxygen in O-coordinated H3PO2, which is made possible by its capability of accepting a proton from P-H to form H4PO2 + and then transfer it to the oxygen. DFT studies have been also carried out on the reaction at the Mo centres to understand the reasons that make these metal centres ineffective for promoting tautomerizatio

Epidemiología básica. Material docente para prácticas en ciencias de la salud

Material docente teórico práctico para apoyar la enseñanza de la epidemiología. Consta de 4 unidades, cada una de ellas con una introducción teórica y unos ejercicios basados en artículos publicados en inglés en revistas científicas

Big data en educación: tipologías de los estudiantes a partir del estudio de las interacciones dentro del triángulo pedagógico

Fac. de Comercio y TurismoFALSEsubmitte

The management of Solid Resources for the creation of optimal learning environments

A nivel mundial existe una problemática de contaminación ambiental, generada por las actividades humanas, en gran medida por el manejo inapropiado de residuos sólidos, por lo cual se pretende que desde las instituciones educativas se generen estrategias pedagógicas que fomenten en los estudiantes actitudes pro ambientales, para preservar su entorno. El estudio tuvo como propósito fomentar el manejo de recursos sólidos para la creación de ambientes óptimos de aprendizaje. La metodología se orientó bajo el enfoque cualitativo, utilizando el tipo de investigación acción, desde un diseño descriptivo, exploratorio. Para la recolección de datos se utilizaron técnicas como; observación participante y diario de campo. Se escogió una muestra de veinticuatro (24) estudiantes desde primero de primaria hasta octavo de básica secundaria de la Institución Educativa Departamental Macondo de la Sede Escuela Rural de varones José celestino Mutis. Se evidencio un manejo integral de los residuos sólidos como parte del proceso de aprendizaje de la institución, llegando a conclusiones con una importancia en la trasformación de los residuos sólidos que mejoren el ambiente escolar.At a global level there is a problem of environmental pollution, generated by human activities, largely due to the improper handling of solid waste, which is why educational institutions are expected to generate pedagogical strategies that encourage students to adopt environmental attitudes, to preserve its environment. The purpose of the study was to promote the management of solid resources for the creation of optimal learning environments. The methodology was oriented under the qualitative approach, using the type of action research, from a descriptive, exploratory design. For the collection of data, techniques such as; participant observation and field diary. A sample of twenty-four (24) students from elementary school to eleventh secondary school was chosen from the Macondo Departmental Educational Institution of the Jose Celestino Mutis Rural School for males. An integral management of solid waste was evidenced as part of the learning process of the institution, reaching conclusions with an importance in the transformation of solid waste that improve the school environment

Kinetic and DFT Studies on the Mechanism of C−S Bond Formation by Alkyne Addition to the [Mo3S4(H2O)9]4+ Cluster

Reaction of [Mo3(μ3-S)(μ-S)3] clusters with alkynes usually leads to formation of two C−S bonds between the alkyne and two of the bridging sulfides. The resulting compounds contain a bridging alkenedithiolate ligand, and the metal centers appear to play a passive role despite reactions at those sites being well illustrated for this kind of cluster. A detailed study including kinetic measurements and DFT calculations has been carried out to understand the mechanism of reaction of the [Mo3(μ3-S)(μ-S)3(H2O)9]4+ (1) cluster with two different alkynes, 2-butyne-1,4-diol and acetylenedicarboxylic acid. Stoppedflow experiments indicate that the reaction involves the appearance in a single kinetic step of a band at 855 or 875 nm, depending on the alkyne used, a position typical of clusters with two C−S bonds. The effects of the concentrations of the reagents, the acidity, and the reaction medium on the rate of reaction have been analyzed. DFT and TD-DFT calculations provide information on the nature of the product formed, its electronic spectrum and the energy profile for the reaction. The structure of the transition state indicates that the alkyne approaches the cluster in a lateral way and both C−S bonds are formed simultaneously

Analyzing factors that influence the folk use and phytonomy of 18 medicinal plants in Navarra

BACKGROUND: This article analyzes whether the distribution or area of use of 18 medicinal plants is influenced by ecological and cultural factors which might account for their traditional use and/or phytonymy in Navarra. This discussion may be helpful for comparative studies, touching as it does on other ethnopharmacological issues: a) which cultural and ecological factors affect the selection of medicinal plants; b) substitutions of medicinal plants in popular medicine; c) the relation between local nomenclature and uses. To analyze these questions, this paper presents an example of a species used for digestive disorders (tea and camomile: Jasonia glutinosa, J. tuberosa, Sideritis hyssopifolia, Bidens aurea, Chamaemelum nobile, Santolina chamaecyparissus...), high blood pressure (Rhamnus alaternus, Olea europaea...) or skin diseases (Hylotelephium maximum, H. telephium, Anagallis arvensis, A. foemina). METHODS: Fieldwork began on January 2004 and continued until December 2006. During that time we interviewed 505 informants in 218 locations in Navarra. Information was collected using semi-structured ethnobotanical interviews, and we subsequently made maps using Arc-View 8.0 program to determine the area of use of each taxon. Each map was then compared with the bioclimatic and linguistic map of Navarra, using the soil and ethnographic data for the region, and with other ethnobotanical and ethnopharmacological studies carried out in Europe. RESULTS: The results clearly show that ecological and cultural factors influence the selection of medicinal plants in this region. Climate and substrate are the most important ecological factors that influence the distribution and abundance of plants, which are the biological factors that affect medicinal plant selection. CONCLUSION: The study of edaphological and climatological factors, on the one hand, and culture, on the other, can help us to understand why a plant is replaced by another one for the same purposes, either in the same or in a different area. In many cases, the cultural factor means that the use of a species is more widespread than its ecological distribution. This may also explain the presence of synonyms and polysemies which are useful for discussing ethnopharmacological data

Big data en educación II: metodologías adaptativas en el proceso de enseñanza-aprendizaje desde el diagnóstico del estudiante

Fac. de Comercio y TurismoFALSEsubmitte