Hambre, mortalidad y crecimiento demográfico en las poblaciones de la Europa preindustrial

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Mecanismos demográficos y oscilaciones a largo plazo de la población europea (1200-1850)

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Góngora: mediador turístico

ES: El objetivo de este artículo es ofrecer las herramientas necesarias para elaborar una guíaturística de la ciudad de Granada a partir de un romance del escritor andaluz Luis deGóngora.Pese a la inseguridad inicial que puede provocar el uso de este tipo de textos en el aula de ELE,nuestra experiencia docente nos ha demostrado que es posible trabajar con textos literarios delSiglo de Oro incluso en cursos iniciales, siendo responsabilidad del profesorado diseñar lamejor adaptación y explotación para cada uno de los niveles de enseñanza. Estos textos no solosirven para sumergir al alumnado en una época importante de la literatura española, sinotambién para darle a conocer aspectos lingüísticos y culturales de manera más motivadoraThe aim of this article is to provide the necessary tools to create a tourist guide to the city ofGranada from an Andalusian romance by the writer Luis de Góngora.Despite the initial uncertainty that the use of such texts may cause in the ELE (Spanish as aforeign language) classroom, our teaching experience has shown us that it is possible to workwith literary texts of the Siglo de Oro even in initial levels with teachers holding responsibilityfor the best design and adaptation of the syllabus to each of the teaching levels. These textsserve not only to immerse students in an important period of Spanish literature, but also tointroduce them to linguistic and cultural aspects in a more motivating way

Saturated hydrocarbon content in olive fruits and crude olive pomace oils

40 Páginas; 14 Tablas; 5 FigurasOlive fruits contain an n-alkane series of saturated hydrocarbons mainly in the pulp. Lower amounts of a complex mixture of paraffins, unresolved by gas chromatography (UCM – unresolved complex mixture), have been found in cuticle, stone (woody shell and seed), olive leaves, and talc used as an aid to olive oil extraction. The amounts of both kinds of hydrocarbons are related to the olive cultivar and are transferred to oils in a proportion depending on the oil-obtaining process (centrifugation or solvent extraction). In olive oil obtained by centrifugation, only n-alkanes were detected. However, in olive oil extracted by second centrifugation, small amounts of UCM paraffins were detected together with the n-alkanes. Olive pomace oils showed a very variable content of both types of hydrocarbons according to the different obtaining process, such as double centrifugation, solvent extraction or centrifugation followed by solvent extraction. ‘White mineral oil’ used in oil extraction machinery is the source of the high concentrations of UCM paraffins found in some olive and olive pomace oils. In the case of second centrifugation olive oil, a maximum limit of 50 mg kg−1 of UCM is suggested, whereas in the case of crude olive pomace oil, it amounts to 250 mg kg−1 plus an additional minimum of 1.0 for the n-alkanes/UCM ratio.The technical expertise of Mrs Rosario González Cordones is acknowledged for her assistance in the laboratory. This work was supported by a grant of the Spanish Ministry of Agriculture, Food, and EnvironmentPeer reviewe

Separate digestion of liquid and solid fractions of thermally pretreated secondary sludge. Assessment and global evaluation

Producción CientíficaThe fractioning into separate liquid and solid fractions obtained by centrifugation of thickened fresh and thermally pretreated (170 ºC, 50 minutes) secondary sludge showed that 30% of the particulate organic matter was released during the pretreatment, correspondingly increasing the methane production of the particulate matter by 30% (from 259 to 329 mL CH4/g VSfed). The responsible of this enhancement was the liquid fraction, as the biodegradability of the solid fraction remained constant after the pretreatment. Mass balances showed that 34% of the VS were released to the liquid fraction, generating nearly 50% of the total methane produced, with much faster kinetics compared to the solid fraction. These results support the hypothesis of a separate liquid-solid digestion of thermally pretreated sludge, which would result in decreasing the digestion volume to half while duplicating the methane productivity per kilogram of sludge fed to digestion

Determinación de hidrocarburos alifáticos saturados en aceites vegetales

The aim of this work is to inform about the development of a simple and reliable off-line method for the determination of saturated hydrocarbons (SH) in vegetable oils. SH can be used as markers for fuel or for mineral oil contamination in edible oils and fats. The method consists of the isolation of the fraction by LC on deactivated silver-silica gel and subsequent on-column GC-FID analysis. This stationary phase was prepared avoiding any kind of activation. The method was developed and validated through the participation in both a proficiency test organized by the Joint Research Centre of the European Commission, and a collaborative trial carried out with trained Spanish laboratories according to the standard ISO 5725. Results showed acceptable repeatability and reproducibility values, and Horrat index, being this protocol in use with satisfactory results ever since. The method’s LOQ is 15 mg.kg–1 and its LOD 5 mg.kg–1, which make it suitable to quantify the 50 mg.kg–1 limit established by the EU, and to detect mineral oil content within the 10–500 mg.kg–1 range. Although other procedures with lower LOD have been developed throughout the years, the use of just regular laboratory equipment such as GC-FID makes the proposed method appropriate for application on a routine basis.El objetivo de este trabajo es el de dar cuenta del desarrollo de un método sencillo y fiable para la determinación de hidrocarburos saturados (HS) en aceites vegetales. Los HS pueden utilizarse como marcadores de contaminación de aceites y grasas comestibles con fuel-oil y aceites minerales El procedimiento consiste en el aislamiento de la fracción correspondiente por cromatografía en columna de gel de sílice argentada sin activar y posterior análisis mediante GC (on-column)-FID. El método se desarrolló y validó mediante la participación en una prueba de competencia organizada por el Joint Research Centre de la Comisión Europea, además de con un ensayo colaborativo llevado a cabo por laboratorios españoles de acuerdo con la norma ISO 5725. Los resultados mostraron valores de repetibilidad y de reproducibilidad aceptables, así como del índice de Horrat, por lo que dicho protocolo se está utilizando con resultados muy satisfactorios. El límite de detección (LDD) es de 5 mg.kg–1, y su límite de cuantificación (LDQ) de 15 mg.kg–1, lo que lo hacen muy adecuado para evaluaciones alrededor del límite de 50 mg.kg–1 establecido por la Unión Europea (UE). Asimismo es fiable para determinar el contenido de aceite mineral en el intervalo entre 10 y 500 mg.kg–1. Si bien se han desarrollado otros procedimientos con menor LDD a lo largo de los años, el uso de equipos habituales de laboratorio tales como GC-FID ha hecho que el método propuesto sea el de elección para su aplicación en cualquier laboratorio de forma rutinaria

Characterization of some olive oil quality aspects by nirs analysis of its fatty acids and triglycerides

The development of new rapid techniques to characterize aspects of the quality of olive oils is of great interest, specially when they do not depend on the use of solvents and reagents. Two main areas of application of these techniques are 1) determining the varietal origin and 2) olive oil authentication against fraudulent mixtures of plant oils. In this work we have developed predictive models based on spectroscopy Vis/NIR that allow analysis of the composition of fatty acids (FAMES) in olive oil and accurately estimating their triglyceride composition. Strategies for developing fraud detection techniques on olive oils, based on the Vis/NIR analysis of their triglycerides composition and 'Equivalent Number of Carbon' (ECN), are being studied.Peer Reviewe

Optimization of a Thermal Hydrolysis process for sludge pre-treatment

Producción CientíficaAt industrial scale, thermal hydrolysis is the most used process to enhance biodegradability of the sludge produced in wastewater treatment plants. Through statistically guided Box-Behnken experimental design, the present study analyses the effect of TH as pre-treatment applied to activated sludge. The selected process variables were temperature (130-180ºC), time (5-50 minutes) and decompression mode (slow or steam-explosion effect), and the parameters evaluated were sludge solubilisation and methane production by anaerobic digestion. A quadratic polynomial model was generated to compare the process performance for the 15 different combinations of operation conditions by modifying the process variables evaluated. The statistical analysis performed exhibited that methane production and solubility were significantly affected by pre-treatment time and temperature. During high intensity pre-treatment (high temperature and long times), the solubility increased sharply while the methane production exhibited the opposite behaviour, indicating the formation of some soluble but non-biodegradable materials. Therefore, solubilisation is not a reliable parameter to quantify the efficiency of a thermal hydrolysis pre-treatment, since it is not directly related to methane production. Based on the operational parameters optimization, the estimated optimal thermal hydrolysis conditions to enhance of sewage sludge digestion were: 140-170°C heating temperature, 5-35min residence time, and one sudden decompression

Glyceridic and Unsaponifiable Components of Microencapsulated Sacha Inchi (Plukenetia huayllabambana L. And Plukenetia volubilis L.) Edible Oils

Sacha inchi (Plukenetia huayllabambana L. and Plukenetia volubilis L.) edible oils were microencapsulated and the lipid fraction of the microparticles was characterized. Hi-cap®, Capsule®, Arabic gum, and the binary combination of Arabic gum + maltodextrin and the ternary combination of Arabic gum + maltodextrin + whey protein isolate, were used as coating materials for the encapsulation process using spray-drying. The surface and the total oils obtained from the microparticles were evaluated in terms of fatty acid composition, minor glyceride polar compounds, polymers, oxidized triglycerides, diglycerides, monoglycerides, and free fatty acids, along with their unsaponifiable components, sterols, and tocopherols. Differences between the original oils and the microencapsulated ones were determined. The most remarkable results included the presence of polymers when there were none in the original oils, the slight loss in ¿3-fatty acids, up to 6%, the loss in tocopherols, in some of the cases around 30%, the maintaining of the phytosterol in their initial levels and the presence of cholesterol in the oils encapsulated with whey protein isolate