Contribución al estudio de la extracción química del Fe3+ contaminante de la madera arqueológica subacuática impregnada con polietilenglicol

Due to the large quantity of contamination by Fe in the waterlogged wood and the composites previously processed with poliethilenglycol, PEG , we have thought the possible extraction and formation of complexes Fe-L (L= 2-Phosphonobuta-1,2,4- tricarboxylic acid, (PBTC)) and their effect on (i) structure of the wood, (ii) structure and physiques characteristics of PEG and (iii) post-treatment contamination by Fe coming from atmospheric agents. This work is a project for to study the formation of these complexes and possible modifications in structures.

Differential sensitivity to tonal frequency and to the rate of modulation of broad-band noise by hearing-impaired listeners

This dissertation examined whether a hearing impairment of the auditory end-organ has the same or a differential effect on the place and periodicity processes. Differential sensitivities for four normally hearing listeners and for both ears of five patients with unilateral Meniere’s disease were measured for tonal frequency and rate of sinusoidally amplitude-modulated noise at common frequencies and rates of the stimulus.

El mal en la narrativa ecuatoriana moderna: Pablo Palacio y la generación de los 30

En este texto el lector podrá encontrar, en primer lugar, una introducción dedicada a explotar las relaciones entre la literatura y el mal en la modernidad, incluyendo una reflexión sobre el problema en la narrativa ecuatoriana surgida en los años veinte y treinta del siglo pasado. En estos años, aparecen en el país distintas propuestas éticas y estéticas que dan cuenta de las nuevas formas de concebir el mundo, y consecuentemente el mal, en tiempos de transformaciones política y social. En la narrativa pueden considerarse dos líneas más visibles que son las abarcadas por este estudio: la de una especie de realismo psicológico, del que se ha escogido a Pablo Palacio como autor representativo; y la narrativa social, representado aquí por los autores de la generación de los treinta. Sobre una selección de textos de estos autores, se sugieren posibilidades de lectura bajo la óptica de la problemática del mal, de esa atracción hacia la violación del orden que forma parte de lo humano. De diferentes formas, estos escritores expresarán las facetas de esta tendencia maldita, introduciendo con audacia lenguajes, motivos y personajes hasta ese momento marginados o maquillados por el arte y el pensamiento ecuatoriano.

FEINE, la organización de los indígenas evangélicos en Ecuador

El presente libro analiza los orígenes, el proceso organizativo e irrupción del Consejo de Pueblos y Organizaciones Indígenas Evangélicos del Ecuador (FEINE), un sector importante del movimiento indígena ecuatoriano que ha sido ignorado por su supuesta escasa significación. Las raíces de FEINE se remontan al proceso de evangelización protestante que se expandió entre los indígenas, caracterizado, en un primer momento, como conservador y, luego, como reformista al asumir el compromiso social en su práctica. Según este estudio, en el desarrollo de FEIN E ha incidido la cooperación privada externa, principalmente de iglesias protestantes, y la de organizaciones no gubernamentales de origen evangélico tanto de Norteamérica como de Europa; aunque también ha recibido fondos del Estado y de organismos internacionales públicos. La investigación evidencia que FEINE cuenta con organizaciones de base en las comunidades indígenas y barrios urbano-marginales de indígenas que han emigrado a las ciudades, y que se articuló, en su primer momento, como organización de iglesias, en las comunidades; luego, como organización social, en las provincias; y, durante los últimos años, ha actuado con características de movimiento social. De esta manera, concluye el autor, FEINE no sólo representa a los indígenas evangélicos agrupados en su seno, sino que, también, disputa la representación indígena y, por tanto, constituye una fuerza movilizadora del movimiento indígena.

Kipus: revista andina de letras. 27 (Reseñas)

Presenta las reseñas de los siguientes libros: VICENTE ROBALINO, La invención del cielo, Quito, Eskeletra, 2008, 54 pp. -- JUAN VALDANO, Juegos de Proteo, Quito, Eskeletra, 2008, 267 pp. -- CRISTÓBAL ZAPATA, Jardín de arena, Arequipa, Cascahuesos Editores, 2009, 57 pp. -- CAROLINA ANDRADE Frágiles, Guayaquil, b@ezeditor.es, 2009, 123 pp. -- Luis Carlos Mussó, Evohé, Guayaquil, Casa de la Cultura Ecuatoriana, Núcleo del Guayas, 2008. -- JORGE VELASCO MACKENZIE, Tatuaje de náufragos, Quito, Ministerio de Cultura del Ecuador/Abya-Yala, 2008, 425 pp. -- RAÚL SERRANO SÁNCHEZ, En la ciudad se ha perdido un novelista. La narrativa de vanguardia de Humberto Salvador, Quito, Ministerio de Cultura de Ecuador/Universidad Andina Simón Bolívar, Sede Ecuador, 2009, 237 pp. -- ALFONSO ORAMAS VELASCO El sacrilegio de Maruja Hernández Guayaquil, b@ezeditor.es, 2010, 109 pp.

La construcción moderna de los maestros y de la infancia en el Ecuador (1925-1948): "la cuestión social", la "escuela activa" y las nuevas ciencias humanas

Este trabajo consta de cuatro capítulos. El primero, “Crisis política, diversificación económica y cambio social”, ofrece una visión de conjunto del período objeto de nuestro estudio. El repaso de las condiciones sociales, económicas y políticas que le caracterizaron permite entender los desplazamientos de los fines de la educación primaria y el marco de las condiciones dentro de las cuales se configuraron los sujetos: maestros y niños escolarizados. El segundo, “Deconstrucción y construcción de identidades: los maestros entre 1925 – 1948”, se arma sobre la base de una serie de preguntas tendientes a dilucidar en última instancia si el sujeto maestro fue capaz de gestionar respuestas a los “regímenes de verdad” establecidos y adoptar posiciones discursivas anti-hegemónicas, en un momento de irrupción de las ideas socialistas que convocaron acciones políticas contestatarias. El tercero, “Niños e imaginarios: los nuevos saberes subjetivizantes”, se introduce en la manera cómo los niños fueron objeto de estudio e intervención. En medio de la enorme influencia que sobre los intelectuales ejercieron las modernas ciencias humanas y los saberes que se desarrollaron sobre el niño, este capítulo analiza sobre todo los dispositivos que se pusieron en marcha para intervenir sobre la mente y el cuerpo de los niños con fines de regeneración racial. El cuarto, “La ‘Escuela Nueva’ y las otras miradas en torno a lo escolar”, refiere a las nuevas pedagogías desde finales del siglo XIX y principios del XX y a la manera cómo éstas operaron sobre los niños rurales y urbanos institucionalizados. En este capítulo se debate en torno a la formación del individuo y a los fines económicos, sociales, morales y políticos vinculados con lo educativo. Cierra el capítulo una mirada sobre la centralización y tecnificación del Ministerio de Educación, que bajo la influencia de la Escuela Nueva armó una organización administrativa escolar fuertemente inspirada en sus planteamientos pedagógicos.

Cholinergic modulation of intrinsic fibre-evoked excitatory transmission contains a nicotinic component in immature but not adult rat piriform cortex, in vitro

The piriform cortex (PC) is highly prone to epileptogenesis, particularly in immature animals, where decreased muscarinic modulation of PC intrinsic fibre excitatory neurotransmission is implicated as a likely cause. However, whether higher levels of acetylcholine (ACh) release occur in immature vs. adult PC remains unclear. We investigated this using in vitro extracellular electrophysiological recording techniques. Intrinsic fibre-evoked extracellular field potentials (EFPs) were recorded from layers II to III in PC brain slices prepared from immature (P14-18) and adult (P>40) rats. Adult and immature PC EFPs were suppressed by eserine (1muM) or neostigmine (1muM) application, with a greater suppression in immature ( approximately 40%) than adult ( approximately 30%) slices. Subsequent application of atropine (1muM) reversed EFP suppression, producing supranormal ( approximately 12%) recovery in adult slices, suggesting that suppression was solely muscarinic ACh receptor-mediated and that some 'basal' cholinergic 'tone' was present. Conversely, atropine only partially reversed anticholinesterase effects in immature slices, suggesting the presence of additional non-muscarinic modulation. Accordingly, nicotine (50muM) caused immature field suppression ( approximately 30%) that was further enhanced by neostigmine, whereas it had no effect on adult EFPs. Unlike atropine, nicotinic antagonists, mecamylamine and methyllycaconitine, induced immature supranormal field recovery ( approximately 20%) following anticholinesterase-induced suppression (with no effect on adult slices), confirming that basal cholinergic 'tone' was also present. We suggest that nicotinic inhibitory cholinergic modulation occurs in the immature rat PC intrinsic excitatory fibre system, possibly to complement the existing, weak muscarinic modulation, and could be another important developmentally regulated system governing immature PC susceptibility towards epileptogenesis.

Radiometric dating of the Siloam Tunnel, Jerusalem

The historical credibility of texts from the Bible is often debated when compared with Iron Age archaeological finds (refs. 1, 2 and references therein). Modern scientific methods may, in principle, be used to independently date structures that seem to be mentioned in the biblical text, to evaluate its historical authenticity. In reality, however, this approach is extremely difficult because of poor archaeological preservation, uncertainty in identification, scarcity of datable materials, and restricted scientific access into well-identified worship sites. Because of these problems, no well-identified Biblical structure has been radiometrically dated until now. Here we report radiocarbon and U-Th dating of the Siloam Tunnel(3-10), proving its Iron Age II date; we conclude that the Biblical text presents an accurate historic record of the Siloam Tunnel's construction. Being one of the longest ancient water tunnels lacking intermediate shafts(11,12), dating the Siloam Tunnel is a key to determining where and when this technological breakthrough took place. Siloam Tunnel dating also refutes a claim(13) that the tunnel was constructed in the second century BC.

Local modes and x,K relations for ethene and propadiene

The results recently obtained by Mills and Robiette on local-mode effects in H2O, NH3 and CH4 type molecules are extended to ethene (C2H4) and propadiene (C3H4) type molecules. General relations among the anharmonic xrs constants and the Darling-Dennison Krrss constants for the stretching vibrations are derived, called “x,K relations”, which allow local-mode effects to be generated by adding the appropriate anharmonic and Darling-Dennison constants to the familiar normal-mode model of molecular vibrations. The general utility of x,K relations is discussed, and the results are reviewed for the molecular types for which they have so far been derived.

Influence of exogenous fibrolytic enzyme level and incubation pH on the in vitro ruminal fermentation of alfalfa stems

A series of in vitro experiments was carried out to examine the impact of enzyme application rate and incubation medium pH on the rate and extent of fermentation of alfalfa stems. In Experiment 1, a commercial enzyme product (Liquicell 2500, Specialty Enzyme and Biochemicals, Fresno, CA, USA) was added to alfalfa stems at six levels: 0, 0.51, 1.02, 2.55, 5.1, and 25.5 mu l/g (control and L1-L5, respectively) to forage DM in a completely randomized design, with a factorial arrangement of treatments. Rate and extent of fermentation and apparent organic matter degradation (OMD) were determined in vitro, using a gas production technique. Addition of enzyme linearly increased (P < 0.01) gas production for up to 12 h (68.9, 70.9, 67.6, 67.9, 71.9, and 74.9 ml/g OM for control, L1-L5, respectively) and OMD for up to 19 h incubation (0.425, 0.444, 0.433, 0.446, 0.443, and 0.451 for control, L1-L5, respectively), but no increases (P > 0.05) were detected thereafter. In Experiment 2, the effect of the same enzyme as used previously (added at 0.51 mu l/g forage DM, directly into the incubation medium), and buffer pH were examined using the ANKOM system, in a completely randomized design. Incubation medium pH was altered using 1 M citric acid, in order to obtain target initial pH values of 6.8 (control, no citric acid added), 6.2, 5.8, and 5.4. Actual initial pH values achieved were 6.72, 6.50, 6.20, and 5.72. Lowering the pH decreased (P < 0.01) dry matter disappearance (DMD) at 18 h incubation (0.339, 0.341, 0.314, and 0.291 for 6.72, 6.50, 6.20, and 5.72, respectively), whereas enzyme addition increased (P < 0.05) DMD at 24 h (0.363 versus 0.387 for control and enzyme-treated, respectively). Addition of enzyme increased (P < 0.05) neutral detergent fibre (NDF), acid detergent fibre (ADF), and hemicellulose (HC) degradation at pH 6.50 (0.077 versus 0.117; 0.020 versus 0.051; 0.217 versus 0.270 for control and enzyme-treated NDF, ADF and hemicellulose degradation, respectively) and 6.72 (0.091 versus 0.134; 0.041 versus 0.079; 0.205 versus 0.261 for control and enzyme-treated NDF, ADF and HC degradation, respectively). It is concluded that the positive effects of this enzyme product were independent of the pre-treatment period, but pH influenced the responses to enzyme supplementation. Under the conditions of this experiment, exogenous fibrolytic enzymes seemed to work better at close to neutrality ruminal pH conditions. (C) 2006 Elsevier B.V. All rights reserved.

A predictive model for early-warning of Septoria leaf blotch on winter wheat

Disease-weather relationships influencing Septoria leaf blotch (SLB) preceding growth stage (GS) 31 were identified using data from 12 sites in the UK covering 8 years. Based on these relationships, an early-warning predictive model for SLB on winter wheat was formulated to predict the occurrence of a damaging epidemic (defined as disease severity of 5% or > 5% on the top three leaf layers). The final model was based on accumulated rain > 3 mm in the 80-day period preceding GS 31 (roughly from early-February to the end of April) and accumulated minimum temperature with a 0A degrees C base in the 50-day period starting from 120 days preceding GS 31 (approximately January and February). The model was validated on an independent data set on which the prediction accuracy was influenced by cultivar resistance. Over all observations, the model had a true positive proportion of 0.61, a true negative proportion of 0.73, a sensitivity of 0.83, and a specificity of 0.18. True negative proportion increased to 0.85 for resistant cultivars and decreased to 0.50 for susceptible cultivars. Potential fungicide savings are most likely to be made with resistant cultivars, but such benefits would need to be identified with an in-depth evaluation.

Thioquinolobactin, a pseudomonas siderophore with antifungal and anti-pythium activity

Under conditions of iron limitation Pseudomonas fluorescens ATCC 17400 produces two siderophores, pyoverdine, and a second siderophore quinolobactin, which itself results from the hydrolysis of the unstable molecule 8-hydroxy-4-methoxy-2-quinoline thiocarboxylic acid (thioquinolobactin). Pseudomonas fluorescens ATCC 17400 also displays a strong in vitro antagonism against the Oomycete Pythium, which is repressed by iron, suggesting the involvement of a siderophore(s). While a pyoverdine-negative mutant retains most of its antagonism, a thioquinolobactin-negative mutant only slowed-down Pythium growth, and a double pyoverdine-, thioquinolobactin-negative mutant, which does not produce any siderophore, totally lost its antagonism against Pythium. The siderophore thioquinolobactin could be purified and identified from spent medium and showed anti-Pythium activity, but it was quickly hydrolysed to quinolobactin, which we showed has no antimicrobial activity. Analysis of antagonism-affected transposon mutants revealed that genes involved in haem biosynthesis and sulfur assimilation are important for the production of thioquinolobactin and the expression of antagonism.

The measurement of maternal plasma corticotropin-releasing factor (CRF) and CRF-binding protein improves the early prediction of preeclampsia

In the present study we measured maternal plasma concentrations of two placental neurohormones, corticotropin-releasing factor (CRF) and CRF-binding protein (CRF-BP), in 58 at-risk pregnant women consecutively enrolled between 28 and 29 wk of pregnancy to evaluate whether their evaluation may predict third trimester-onset preeclampsia ( PE). The statistical significance was assessed by t test. The cut-off points for defining altered CRF and CRF-BP levels for prediction of PE were chosen by receiving operator characteristics curve analysis, and the probability of developing PE was calculated for several combinations of hormone testing results. CRF and CRF-BP levels were significantly ( both P < 0.0001) higher and lower, respectively, in the patients (n = 20) who later developed PE than in those who did not present PE at follow-up. CRF at the cut-off 425.95 pmol/liter achieved a sensitivity of 94.8% and a specificity of 96.9%, whereas CRF-BP at the cut-off 125.8 nmol/liter combined a sensitivity of 92.5% and a specificity of 82.5% as single markers for prediction of PE. The probability of PE was 34.5% in the whole study population, 93.75% when both CRF and CRF-BP levels were changed, and 0% if both hormone markers were unaltered. The measurement of CRF and CRF-BP levels may add significant prognostic information for predicting PE in at-risk pregnant women.