High Aluminum Resistance in Buckwheat1 : I. Al-induced Specific Secretion of Oxalic Acid from Root Tips

High Al resistance in buckwheat (Fagopyrum esculentum Moench. cv Jianxi) has been suggested to be associated with both internal and external detoxification mechanisms. In this study the characteristics of the external detoxification mechanism, Al-induced secretion of oxalic acid, were investigated. Eleven days of P depletion failed to induce secretion of oxalic acid. Exposure to 50 μm LaCl3 also did not induce the secretion of oxalic acid, suggesting that this secretion is a specific response to Al stress. Secretion of oxalic acid was maintained for 8 h by a 3-h pulse treatment with 150 μm Al. A nondestructive method was developed to determine the site of the secretion along the root. Oxalic acid was found to be secreted in the region 0 to 10 mm from the root tip. Experiments using excised roots also showed that secretion was located on the root tip. Four kinds of anion-channel inhibitors showed different effects on Al-induced secretion of oxalic acid: 10 μm anthracene-9-carboxylic acid and 4,4′-diisothiocyanatostilbene-2,2′-disulfonate had no effect, niflumic acid stimulated the secretion 4-fold, and phenylglyoxal inhibited the secretion by 50%. Root elongation in buckwheat was not inhibited by 25 μm Al or 10 μm phenylglyoxal alone but was inhibited by 40% in the presence of Al and phenylglyoxal, confirming that secretion of oxalic acid is associated with Al resistance.

Los intérpretes en la corte de Al-Ḥakam II de Córdoba

Este artículo ofrece un análisis de datos históricos sobre los intérpretes de embajadas en la corte del califa de Córdoba Al-Ḥakam II (961-976). El objetivo principal es caracterizar, en la medida de lo posible, las funciones de los intérpretes en esa época. Entre los temas tratados en este estudio se destacan la relación entre los intérpretes y el monarca, las lenguas traducidas en una sociedad plurilingüe y diglósica, las modalidades de interpretación utilizadas, el perfil de los intérpretes –no solo como mediadores orales sino también como traductores de documentos oficiales–, y, por fin, su procedencia social y cultural, lo que nos daría una idea de su competencia traductora.

Noticias de ataques y destrucciones en Orihuela durante el período andalusí (ss. VIII-XIII)

Tras resumirse "Los elementos esenciales de la trama urbana de Orihuela", se estudian los principales hechos históricos durante el período islámico de la ciudad de Orihuela "s. VIII-XIII) en que hay noticia de ataques militares a la ciudad y destrucciones : El ataque de los normandos a Orihuela en 245 H ./859 e.C.; Aceifa del califa ‘Abd al-Raḥmān III al-Nāṣir contra Orihuela y sus rebeldes; La "fitnat al-barbar" o guerra civil que acabó con el califato andalusí; El terremoto posterior a 440 H/1048-9 e.C. que asoló toda la vega del río Segura y finalmente la conquista cristiana de Orihuela. Como conclusiones para el estudio del urbanismo musulmán de Orihuela se demuestra que solo hubo destrucciones en el trazado urbano de importancia como resultado del mencionado terremoto que asoló y destruyó las ciudades de Murcia, Orihuela y toda la Vega Baja del río Segura.

Teaching-learning process of historical heritage: a Journey as a beginning, path and end

The implantation of new university degrees within the European Higher Education Area implies the need of innovative methodologies in teaching and learning to improve the skills and competencies of students and to answer the growing needs that society continuously demands to heritage management experts. The present work shows an application of the teaching methodology proposed during the international workshop entitled “I International Planning Preservation Workshop. Learning from Al Andalus”, which included the participation of the University of Alicante and Granada, Università Politecnico di Milano and Hunter College City University of New York; where we tried to dissolve traditional boundaries derived of interuniversity cooperation programs. The main objective of the workshop was to discuss and debate the role of urban Historical Centers within the Global Heritage by the integrated work through multidisciplinary teams and the creation of a permanent international working group between these universities to both teach and research. The methodology of this workshop was very participatory and considered the idea of a new learning process generated by "a journey experience." A trip from global to local (from the big city to the small village) but also a trip from the local (historical) part of a big city to the global dimension of contemporary historical villages identified by the students through a system of exhibition panels in affinity groups, specific projects proposed by lecturers and teachers or the generation of publications in various areas (texts, photographs, videos, etc.). So, the participation of the students in this multidisciplinary meeting has enhanced their capacity for self-criticism in several disciplines and has promoted their ability to perform learning and research strategies in an autonomous way. As a result, it has been established a permanent international work structure for the development of projects of the Historical City. This relationship has generated the publication of several books whose contents have reflected the conclusions developed in the workshop and several teaching proposals shared between those institutions. All these aspects have generated a new way of understanding the teaching process through a journey, in order to study the representative role of university in the historical heritage and to make students (from planning, heritage management, architecture, geography, sociology, history or engineering areas) be compromised on searching strategies for sustainable development in the Contemporary City.

Agua, derecho de uso y utilidad en el regadío de tradición andalusí del Reino de Valencia

El origen de la normativa escrita sobre el uso de las aguas en el territorio peninsular levantino plantea diversas incógnitas. Las primera de ellas sobre los quienes fueron los protagonistas en la redacción y determinación de ese derecho. La segunda sobre el papel que la costumbre de los sarracenos desempeñó en la preservación de tradiciones jurídicas, mantenimiento de infraestructuras y gestión del agua. La tercera tiene que ver con el modo de aunar intereses de comunidades distintas desde el punto de vista religioso y jurídico sobre el derecho de uso de forma equitativa y proporcional a necesidades no necesariamente coincidentes. Lo cierto es que las fuentes conservadas sobre el proceso de reconquista y población siguen siendo una de las mejores referencias para despejar incógnitas y justificar la tradición y pervivencia de un derecho inmemorial y vigente en algunas de sus formas y manifestaciones, no solo en el marco levantino sino en otros muchos espacios de la cuenca mediterránea con idénticas características medioambientales y geo-climáticas.

Significación de los relatos de ‘ağā’ib dentro de la riḥla de Ibn al-Ṣabbāḥ

La obra de Ibn al-Ṣabbāḥ concita en su interior diversos géneros, y en especial el género riḫla. Sin embargo, como toda obra árabe medieval, posee características de otros géneros, como el geográfico, el autobiográfico y, en el caso del presente estudio, reúne relatos de ‘ağā’ib o ‘maravillas”. El artículo muestra ejemplos de cómo el unicum titulado Niṣāb al-ajbār wa-taḏkirat al-ajyār recoge la tradición de la literatura de maravillas o de ‘ağā’ib de la literatura árabe clásica.

Dificultades en la traducción de al-Farāfīr de Yūsuf Idrīs

En este artículo hablamos en primer lugar de la obra teatral al-Farāfīr de Yūsuf Idrīs. Abordamos las dificultades de la traducción del árabe dialectal egipcio al castellano. Nos hemos acercado al término al-Farāfīr desde un punto de vista lingüístico y pragmático. Exponemos la dificultad de la traducción literaria entre dos lenguas pertenecientes a ámbitos socio-culturales muy diferentes.

Al-Qaeda and the Islamic State: A comparative study of the Jihadi narratives

Thesis (Master's)--University of Washington, 2016-06

Stress corrosion cracking and hydrogen embrittlement of an Al-Zn-Mg-Cu alloy

The age hardening, stress corrosion cracking (SCC) and hydrogen embrittlement (HE) of an Al-Zn-Mg-Cu 7175 alloy were investigated experimentally. There were two peak-aged states during ageing. For ageing at 413 K, the strength of the second peak-aged state was slightly higher than that of the first one, whereas the SCC susceptibility was lower, indicating that it is possible to heat treat 7175 to high strength and simultaneously to have high SCC resistance. The SCC susceptibility increased with increasing Mg segregation at the grain boundaries. Hydrogen embrittlement (HE) increased with increased hydrogen charging and decreased with increasing ageing time for the same hydrogen charging conditions. Computer simulations were carried out of (a) the Mg grain boundary segregation using the embedded atom method and (b) the effect of Mg and H segregation on the grain boundary strength using a quasi-chemical approach. The simulations showed that (a) Mg grain boundary segregation in Al-Zn-Mg-Cu alloys is spontaneous, (b) Mg segregation decreases the grain boundary strength, and (c) H embrittles the grain boundary more seriously than does Mg. Therefore, the SCC mechanism of Al-Zn-Mg Cu alloys is attributed to the combination of HE and Mg segregation induced grain boundary embrittlement. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Influence of calcium on the microstructure and properties of an Al-7Si-0.3Mg-xFe alloy

The effect of Ca addition on the microstructure, physical characteristics (density/porosity), and mechanical properties (tensile and impact strength) has been investigated in an Al-7Si-0.3Mg-xFe (x = 0.2, 0.4, and 0.7) alloy. The size of Al-Fe intermetallic platelets (beta-Al5FeSi) increased with increasing Fe content. The addition of Ca modified the eutectic microstructure and also reduced the size of intermetallic Fe-platelets, causing improved elongation and impact strengths. A low level of Ca addition (39 ppm) reduced the porosity of the alloys. The tensile strength was decreased marginally with Ca addition. However, Ca addition improved the ductility of the alloy by 18.3, 16.7, and 44 pet and the impact strength by 44, 48, and 15.8 pct for Fe contents of 0.2, 0.4, and 0.7 pct, respectively.

Reactive processing of polymers:functionalisation of ethylene-propylene diene terpolymer (EPDM) in the presence and absence of a co-agent and effect of functionalised EPDM on compatibilisation of poly(ethylene terephthalate)/EPDM blends

Ethylene-propylene diene terpolymer (EPDM) was functionalized with glycidyl methacrylate (GMA) during melt processing by free radical grafting with peroxide initiation in the presence and absence of a reactive comonomer trimethylolpropane triacrylate (Tris). Increasing the peroxide concentration resulted in an increase in the GMA grafting yield, albeit the overall grafting level was low and was accompanied by higher degree of crosslinking of EPDM which was found to be the major competing reaction. The presence of Tris in the grafting system gave rise to higher grafting yield produced at a much lower peroxide concentration though the crosslinking reactions remained high but without the formation of GMA-homopolymer in either of the two systems. The use of these functionalized EPDM (f-EPDM) samples with PET as compatibilisers in binary and ternary blends of PET/EPDM/f-EPDM was evaluated. The influence of the different functionalisation routes of the rubber phase (in presence and absence of Tris) and the effect of the level of functionality and microstructure of the resultant f-EPDM on the extent of the interfacial reaction, morphology and mechanical properties was also investigated. It is suggested that the mechanical properties of the blends are strongly influenced by the performance of the graft copolymer, which is in turn, determined by the level of functionality, molecular structure of the functionalized rubber and the interfacial concentration of the graft copolymer across the interface. The cumulative evidence obtained from torque rheometry, scanning electron microscopy, SEM, dynamic mechanical analysis (DMA), tensile mechanical tests and Fourier transform infrared (FTIR) supports this. It was shown that binary and ternary blends prepared with f-EPDM in the absence of Tris and containing lower levels of g-GMA effected a significant improvement in mechanical properties. This increase, particularly in elongation to break, could be accounted for by the occurrence of a reaction between the epoxy groups of GMA and the hydroxyl/carboxyl end groups of PET that would result in a graft copolymer which could, most probably, preferentially locate at the interface, thereby acting as an 'emulsifier' responsible for decreasing the interfacial tension between the otherwise two immiscible phases. This is supported by results from FTIR analysis of the fractionated PET phase of these blends which confirm the formation of an interfacial reaction, DMA results which show a clear shift in the T s of the blend components and SEM results which reveal very fine morphology, suggesting effective compatibilisation that is concomitant with the improvement observed in their tensile properties. Although Tris has given rise to highest amount of g-GMA, it resulted in lower mechanical properties than the optimized blends produced in the absence of Tris. This was attributed to the difference in the microstructure of the graft and the level of functionality in these samples resulting in less favourable structure responsible for the coarser dispersion of the rubber phase observed by SEM, the lower extent of T shift of the PET phase (DMA), the lower height of the torque curve during reactive blending and FTIR analysis of the separated PET phase that has indicated a lower extent of the interfacial chemical reaction between the phases in this Tris-containing blend sample. © 2005 Elsevier Ltd. All rights reserved.

La alquería de Pereila, un poblamiento andalusí en la Algarbía malagueña

El poblamiento rural de origen andalusí en la antigua Algarbía malagueña es un gran desconocido para la historiografía medieval. Las excavaciones y prospecciones con metodología arqueológica son prácticamente inexistentes y el recurso a la documentación escrita, en concreto la de origen castellana, ha dado un resultado muy limitado. Como excepción tenemos la información correspondiente al antiguo espacio residencial de Pereila y su territorio. La alquería estaba situada dentro del actual término municipal de Coín (Málaga) y un pleito en el 1537 entre el cabildo Catedralicio de Málaga y los beneficiados de Coín por el cobro del diezmo de dicho lugar, nos ha aportado una información valiosa sobre los límites territoriales del poblamiento, y en menor medida, de sus espacios de trabajo. También utilizaremos la metodología propia de la arqueología extensiva y los principios de la arqueología hidráulica que nos servirán para complementar la información aportada por la documentación escrita.

¿Fue la crisis política del Occidente musulmán del siglo XIII debida a un cambio climático? Una aproximación histórica al fin del Periodo Cálido Medieval

Durante el siglo XIII se produjo una sucesión de revueltas que supuso la desaparición del Imperio almohade y su sustitución por poderes regionales en al-Andalus, el Magreb y el Magreb al-Aqsà. La historiografía ha presentado el surgimiento y pugna entre estos poderes como un fenómeno social, político e, incluso, cultural y religioso, con el que se ha podido explicar su aniquilación o marginalización. Este trabajo pretende contextualizar los hechos desde una perspectiva medioambiental, de forma que la desintegración del califato almohade, el surgimiento de aquellos poderes y la progresión de los reinos cristianos en la península ibérica puedan entenderse desde una visión global de cambio climático y una posible crisis agrícola.