937 resultados para C-15-Acetogenin


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El objetivo general de esta investigación es analizar el proceso de incorporación del gobierno electrónico en Colombia, así como evaluar el impacto de las TIC en asuntos del gobierno y su relación con los ciudadanos, puesto que en la práctica se desea incrementar la participación en asuntos públicos y una inclusión ciudadana a través de las TIC. El éxito del Gobierno en Línea dependerá de la transparencia y confianza creciente entre el gobierno y los ciudadanos y toma como referencia la estrategia de Gobierno en Línea 2008-2010. Será usada, una metodología exploratoria y descriptiva sobre la base de documentos bibliográficos y publicaciones periódicas y académicas.

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En el estudio de caso se podrá encontrar información relacionada a la empresa ASTRO MAQUINARIA Ltda. la cual lleva más de 20 años en el mercado, generando soluciones a las necesidades de maquinaria y equipos, especialmente en el área de bombeo. Desde el principio la empresa ha estado importando desde Estados Unidos el portafolio de productos que ofrecen, actualmente tienen la representación comercial de la empresa Pentair Pump Group. Este estudio de caso pretende identificar cual es la estrategia de internacionalización empleada por la empresa, la toma de decisiones, la cadena de abastecimiento, relaciones comerciales, entre otras; las cuales han logrado la perdurabilidad y el crecimiento de la empresa desde su inicio. La metodología utilizada para el desarrollo de este estudio de caso se basara en variables cualitativas que permiten el análisis profundo y la indagación sobre el fenómeno, igualmente se utilizaran algunas variables cuantitativas para observar la situación actual de la empresa y el desempeño de la misma en el sector de comercialización de maquinaria pesada.

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Las redes sociales digitales han transformado la forma de comunicarse en el Siglo XXI. Twitter es la red social más destacada para los periodistas colombianos pues según un estudio de la consultora de comunicación Burson-Marsteller, el 47% de los comunicadores colombianos utilizan esta red social para construir noticias (Burson-Marsteller, 2013). Por su popularidad, los medios de comunicación han puesto la mirada sobre esta red social pues ven en esta un nuevo espacio de información, razón por la cual se han transformado para convertir a Twitter en un nuevo conducto para la transmisión de sucesos coyunturales. En Colombia, los medios periodísticos de tradición intentan modificar su estructura y rutinas para adecuarse al nuevo molde comunicativo que propone la inclusión de las redes sociales digitales. Este artículo intenta desvelar cuáles son esos cambios que ha sufrido el periodismo colombiano, teniendo como base su relación con Twitter.

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El objetivo de este trabajo es presentar un modelo de implementación, aplicación y medición de diferentes procesos de eco-innovación al interior de una empresa. Para lograr este fin, se presenta una estructura donde se evalúan los procesos productivos del sector industrial colombiano y su relación con la eco-innovación, esto para realizar un filtro dentro de la propuesta y poder dirigir el proyecto a empresas idóneas para adoptar un modelo eco-innovador. Este modelo está basado en diferentes métodos de desarrollo de conceptos como lo son la innovación, el desarrollo sostenible y un término que en los últimos tiempos ha venido tomando fuerza dentro del sector empresarial mundial, el término Eco-amigable. Este término será entonces una base para la relación de los procesos productivos con la adaptación de la eco-innovación para generar un desarrollo sostenible referente al ambiente y un posicionamiento empresarial industrial dentro de un mercado altamente competitivo.

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El interés de esta monografía es analizar el papel que han jugado las organizaciones de izquierda en las recientes movilizaciones agrarias. Para esto, se evaluará la relación entre el Polo Democrático Alternativo y el paro de los corteros de caña del 2008 y las movilizaciones lecheras en contra de los decretos que prohibían la comercialización de leche en cantina. El trabajo aborda un estudio histórico desde mitad del siglo XX que pretende evidenciar la relación gremio-gobierno y su, posterior, decaimiento; a su vez, la táctica que han empleado las organizaciones de izquierda para permear mayores sectores agrarios y, en especial, el mecanismo adoptado en la última década por el Polo Democrático Alternativo.

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Two novel benzodioxotetraaza macrocycles [2,9-dioxo-1,4,7,10-tetraazabicyclo[10.4.0]1,11-hexadeca-1(11),13,15-triene (H(2)L1) and 2,10-dioxo-1,4,8,11-tetraazabicyclo[11.4.0]1,12-heptadeca-1(12),14,16-triene (H(2)L2)] were synthesized by a [1 + 1] crablike cyclization. The protonation constants of both ligands were determined by H-1 NMR titration and by potentiometry at 25.0 degrees C in 0.10 M ionic strength in KNO3. The latter method was also used to ascertain the stability constants of their copper(II) complexes. These studies showed that the CuL1 complex has a much lower thermodynamic stability than the CuL2, and the H(2)L2 displays an excellent affinity for copper(II), due to the good fit of copper(II) into its cavity. The copper complexes of the novel ligands were characterized by electronic spectroscopy in solution and by crystal X-ray diffraction. These studies indicated that the copper center in the CuL1 complex adopts a square-pyramidal geometry with the four nitrogen atoms of the macrocycle forming the equatorial plane and a water molecule at axial position, and the copper in the CuL2 complex is square-planar. Several labeling conditions were tested, and only H(2)L2 could be labeled with Cu-67 efficiently (> 98%) in mild conditions (39 degrees C, 15 min) to provide a slightly hydrophilic radioligand (log D = -0.19 +/- 0.03 at pH 7.4). The in vitro stability was studied in the presence of different buffers or with an excess of diethylenetriamine-pentaethanoic acid. Very high stability was shown under these conditions for over 5 days. The incubation of the radiocopper complex in human serum showed 6% protein binding.

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The synthesis, characterisation, X-ray single crystal structures and magnetic properties of three new basal-apical mu(2)-1,1-azide-bridged complexes [(CuLN3)-N-1](2) (1), [(CuLN3)-N-2](2) (2) and [(CuLN3)-N-3](2) (3) with very similar tridentate Schiff-base blocking ligands {HL1 = N-[2-(ethylamino) ethyl] salicylaldimine; HL2 = 7-(ethylamino)-4-methyl-5-azahept-3-en-2-one; HL3 = 7-amino-4-methyl-5-azaoct-3-en-2-one} have been reported [complex 1: monoclinic, P2(1)/c, a = 8.390(2), b = 7.512(2), c = 19.822(6) Angstrom, beta = 91.45(5)degrees; complex 2: monoclinic, P2(1)/c, a = 8.070(9), b = 9.787(12), c = 15.743(17) A, beta = 98.467(10)degrees; complex 3: monoclinic, P2(1)/n, a = 5.884(7), b = 16.147(18), c = 11.901(12) Angstrom, beta = 90.050(10)degrees]. The structures consist of neutral dinuclear entities resulting from the pairing of two mononuclear units through end-on azide bridges connecting an equatorial position of one copper centre to an axial position of the other, The copper ions adopt a (4+1) square-based geometry in all the complexes. In complex 2, there is no inter-dimer hydrogen-bonding. However, complexes 1 and 3 form two different supramolecular structures in which the dinuclear entities are linked by H-bonds giving one-dimensional systems. Variable temperature (300-2 K) magnetic-susceptibility measurements and magnetisation measurements at 2 K reveal that all three complexes have antiferromagnetic coupling. Magneto-structural correlations have been made taking into consideration both the azido bridging ligands and the existence of intermolecular hydrogen bonds. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).

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The potential longevity of japonica rice (Oryza sativa L. subsp. japonica) seed is particularly sensitive to high temperature – and thus climate change – during development and maturation. Cultivar Taipei 309 was grown at 28/208C (12 h/12 h) and then from 19 DAA (days after 50% anthesis), when seeds were just over half filled, at 28/208C, 30/228C, 32/248C or 34/268C (12 h/12 h). Whereas ability to germinate ex planta had been achieved in almost all seeds by 24 DAA, only half the population were desiccation tolerant. Desiccation tolerance continued to increase over the subsequent 28 d, similarly at all four temperatures. Subsequent longevity, assessed by p50 (period in days to reduce viability to 50% in hermetic storage at 408C with c. 15% moisture content), increased progressively at 28/208C until 38 DAA, and remained constant until the final harvest (52 DAA). The three warmer temperature regimes provided similar longevity to 28/208C at any one harvest, except at 38 DAA where the warmest (34/268C) was poorer. That temperature regime also provided greater seed-to-seed variability within each survival curve. The results confirm that appreciable improvement in seed quality occurs during seed development and also subsequent maturation in japonica rice, but that increase in temperature from 28/208C to 34/268C during late seed filling onwards has comparatively little effect thereon. Comparison with previous investigations suggests that seed quality development may be less sensitive to high temperatures during late development and maturation than during the early seed development that precedes it.

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Carbamazepine forms a 1:1 solvate with trifluoroacetic acid (systematic name: 5H-dibenzo[b,f] azepine-5-carboxamide trifluoroacetic acid solvate), C(15)H(12)N(2)O center dot C(2)HF(3)O(2). The compound crystallizes with one molecule of carbamazepine and one of trifluoroacetic acid in the asymmetric unit to form an R(2)(2)(8) motif. The solvent molecule is disordered over two sites, with site-occupancy factors 0.53 (1) and 0.47 (1).

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The preparation, the IR and ligand field spectra and the structures of the mixed-ligand addition compounds [(N,N-dimethyl-1,2-diaminoethane)bis(1-(2-thienyl)-4,4,4-trifluoro-1,3-butanedionato)cobalt(II)], [Co(thtf)2me2en], and [(N,N,N′,N′-tetramethyl-1,2-diaminoethane)bis(1-(2-thienyl)-4,4,4-trifluoro-1,3-butanedionato)cobalt(II)], [Co(thtf)2me4en], are reported. The structures were determined by single crystal X-ray diffraction analysis (monoclinic, space group P21/c, Z=4 with a=10.708(6), b=19.531(6), c=13.352(6) Å, β=111.64(10)°, R1=0.0642 and wR2=0.1719 for [Co(thtf)2(me2en)] and a=12.033(6), b=15.565(6), c=15.339(6) Å, β=92.57(6)°, R1=0.0612 and wR2=0.1504 for [Co(thtf)2me4en]). The structures are distorted octahedral and the shortest cobalt–cobalt separation distances are 5.388(2) Å in [Co(thtf)2me2en] and 8.675(3) Å in [Co(thtf)2me4en]. In both compounds the diamine molecules attain the gauche conformation. The U(Z,Z) conformation of the β-dione leads to a semi-chair conformation of the β-dionato chelate rings. The relative orientation of the groups attached to the β-dionato moiety depends on the extent of stereoelectronic effects the N-substitution of the diamine entails. In [Co(thtf)2me2en] the intraligand distance separating the trifluoromethyl carbon atoms is 5.281(18) Å while in [Co(thtf)2me2en] it increases to 8.338(9) Å. The cobalt–cobalt separation distance, the orientation of the chelate rings and the extent of N-substitution seem to affect hydrogen bonding. While in [Co(thtf)2me2en] inter- and intraligand hydrogen bonding is implicated, it is totally absent in [Co(thtf)2me4en].

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Bioaccessibility tests can be used to improve contaminated land risk assessments. For organic pollutants a ‘sink’ is required within these tests to better mimic their desorption under the physiological conditions prevailing in the intestinal tract, where a steep diffusion gradient for the removal of organic pollutants from the soil matrix would exist. This is currently ignored in most PBET systems. By combining the CEPBET bioaccessibility test with an infinite sink, the removal of PAH from spiked solutions was monitored. Less than 10% of spiked PAH remained in the stomach media after 1 h, 10% by 4 h in the small intestine compartment and c.15% after 16 h in the colon. The addition of the infinite sink increased bioaccessibility estimates for field soils by a factor of 1.2–2.8, confirming its importance for robust PBET tests. TOC or BC were not the only factors controlling desorption of the PAH from the soils.

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This paper explores the nature and chronology of La Tène and early Roman unenclosed agglomerations in central-eastern France. It has been prompted by the discovery of a c. 115 ha La Tène D2b/Augustan (c. 50 bc to ad 15) site close to Bibracte in the Morvan, located around the source of the River Yonne. This complex provides a new perspective on the chronology and role of Late La Tène and early Roman unenclosed settlements, adding further complexity to the story of the development of Late La Tène oppida. It indicates that these ‘agglomerations’ followed remarkably varied chronological trajectories, raising important issues concerning the nature of landscape and social change at the end of the Iron Age. Dieser Aufsatz untersucht den Charakter und die Datierung von latènezeitlichen und frührömischen offenen Siedlungen im östlichen Zentralfrankreich. Die Anregung dazu erfolgte durch die Entdeckung einer Latène D2b-zeitlichen bis augusteischen (ca. 50 v. Chr. – 15 n. Chr.) Anlage im Morvan bei Bibracte, die ca. 115 ha Fläche bedeckt und sich um die Quellen des Flusses Yonne erstreckt. Es wird vorgeschlagen, dass dieser Siedlungskomplex eine Ergänzung, aber auch einen Kontrast zu den üblichen Interpretationsmodellen von spätlatènezeitlichen und frührömischen, offenen Großsiedlungen und ihrer zeitlichen Entwicklung darstellt, und weiter zur Komplexität der Entwicklung spätlatènezeitlicher Oppida beiträgt. Es deutet sich an, dass einige der ‘Agglomerationen’ anderen Entwicklungslinien folgen, die wichtige Fragen zur Landschaftsgenese und zum sozialen Wandel am Ende der Eisenzeit aufwerfen. Cet article a pour but d'explorer la nature ainsi que la chronologie des agglomérations ouvertes apparaissant à La Tène Final et au début de la période gallo-romaine du Centre-Est de la France. Il fut inspiré et écrit suite à la découverte dans le Morvan d'un site de 115 ha datant de La Tène D2b et de la période Augustéenne (50 av. J.C. à 15 ap. J.C.) s'étirant autour des Sources de l'Yonne. Cette agglomération apporte de nouvelles perspectives sur la chronologie et sur le rôle des habitats ouverts à la fin de l'Âge du Fer ainsi qu'au début de l'époque gallo-romaine apportant des éléments amenés à renforcer le caractère complexe de l'histoire du développement des oppida à La Tène Final. Cette synthèse tend à démontrer que ces agglomérations suivaient des trajectoires chronologiques variées, élevant un certain nombre de questions, et donc des nouvelles problématiques, concernant la nature du paysage et du changement social à la fin de l'Âge du Fer.

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The solvothermal synthesis and characterization of two indium selenides with stoichiometry [NH4][InSe2] is described. Yellow [NH4][InSe2] (1), which exhibits a layered structure, was initially prepared in an aqueous solution of trans-1,4-diaminocyclohexane, and subsequently using a concentrated ammonia solution. A red polymorph of one-dimensional character, [NH4][InSe2] (2), was obtained using 3,5-dimethylpyridine as solvent. [NH4][InSe2] (1) crystallizes in the non-centrosymmetric space group Cc (a=11.5147(6), b=11.3242(6), c=15.9969(9) Å and β=100.354(3)°). The structural motif of the layers is the In4Se10 adamantane unit, composed of four corner-linked InSe4 tetrahedra. These units are linked by their corners, forming [InSe2]− layers which are stacked back to back along the c-direction, and interspaced by [NH4]+cations. The one-dimensional polymorph, (2), crystallizes in the tetragonal space group, I4/mcm (a=8.2519(16), c=6.9059 (14) Å). This structure contains infinite chains of edge-sharing InSe4 tetrahedra separated by [NH4]+ cations.

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The effect of high pressure homogenisation (HPH) and heat treatments on physicochemical properties and physical stability of almond and hazelnut milks was studied. Vegetable milks were obtained and homogenised by applying 62, 103 and 172 MPa (MF1, MF2 and MF3, respectively). Untreated and MF3 samples were also submitted to two different heat treatments (85 °C/30 min (LH) or 121 °C/15 min (HH)). Physical and structural properties of the products were greatly affected by heat treatments and HPH. In almond milk, homogenised samples showed a significant reduction in particle size, which turned from bimodal and polydisperse to monodisperse distributions. Particle surface charge, clarity and Whiteness Index were increased and physical stability of samples was improved, without affecting either viscosity or protein stability. Hazelnut beverages showed similar trends, but HPH notably increased their viscosity while change their rheological behaviour, which suggested changes in protein conformation. HH treatments caused an increment of particle size due to the formation oil droplet-protein body clusters, associated with protein denaturation. Samples submitted to the combined treatment MF3 and LH showed the greatest stability.