1,222 research outputs found

    Fuel loading and flammability in the Mediterranean Basin woody species with different post-fire regenerative strategies

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    12 páginas, 5 figuras, 3 tablas.The flammability and combustibility of plant communities are determined by species features related to growth-form, structure and physiology. In some ecosystems, such as the Mediterranean ones, these characteristics may contribute to the existence of fire-prone species. We measured several parameters associated with the flammability and fuel loading of dominant woody species with different post-fire regenerative strategies ( seeders and non-seeders) in shrublands in the western Mediterranean Basin. Overall, seeder species show lower fuel load but are more prone to burning owing to a higher dead-to-live fuel ratio, live fine-fuel proportion and dead fine-fuel proportion. Moreover, they burst into flame at lower temperatures than non-seeders. In the Mediterranean Basin, most seeder species emerged mainly during the Quaternary, under a highly fluctuating Mediterranean climate and during recurrent fires. We propose that properties related to the combustibility and flammability of seeders may be the result of selective pressures associated with both fire and climate. These results suggest that ecosystems dominated by seeder species are more susceptible to fire risk than those dominated by non-seeder species in the Mediterranean Basin. Therefore, the proportion of these types of species resulting from previous fire or management history is likely to determine the characteristics of future fire events.We thank M. Jané, E. Martí, A. Vilà-Cabrera, J. Garcia, B. Moreira, S. Ribeiro and C. Beseler for helping in the field and in the laboratory work. Also, special thanks are due to J. Piñol for his advice and suggestions, and to J. Peñuelas and G. Alessio for supporting the flammability tests. This study was funded by the Department of Universities, Research and Information Society of the Generalitat de Catalunya, the European social funds, and the Spanish Ministerio de Ciencia y Tecnología (MCYT) projects REN 2003–07198 and CGL2006–01293/BOS. It also contributes to the European research group (GDRE) ‘Mediterranean and mountain ecosystems in a changing world’ funded by the Generalitat de Catalunya and CNRS (Centre National de la Recherche Scientifique). CEAM (Fundación Centro de Estudios Ambientales del Mediterráneo) is supported by the Generalitat Valenciana and Bancaixa.Peer reviewe

    Chromosomal Evolution In The South American Nymphalidae.

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    We give the chromosome numbers of about 80 species or subspecies of Biblidinae as well as of numbers of neotropical Libytheinae (one species), Cyrestinae (4) Apaturinae (7), Nymphalinae (about 40), Limenitidinae (16) and Heliconiinae (11). Libytheana has about n=32, the Biblidinae, Apaturinae and Nymphalinae have in general n=31, the Limenitidinae have n=30, the few Argynnini n=31 and the few species of Acraeni studied have also mostly n=31. The results agree with earlier data from the Afrotropical species of these taxa. We supplement these data with our earlier observations on Heliconiini, Danainae and the Neotropical Satyroid taxa. The lepidopteran modal n=29-31 represents clearly the ancestral condition among the Nymphalidae, from which taxa with various chromosome numbers have differentiated. The overall results show that Neotropical taxa have a tendency to evolve karyotype instability, which is in stark contrast to the otherwise stable chromosome numbers that characterize both Lepidoptera and Trichoptera.144137-4

    Addressing sustainable food management in hotels: proposing a framework and examining hotel groups

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    Purpose - Sustainable food practices have been recognised as a key issue in efforts to improve and report sustainable tourism practices, given the importance of the social, environmental and economic impacts of the food industry throughout its entire chain of production - from farm to fork. From this standpoint, the aim of the present paper is to propose a comprehensive framework for reporting or making decisions concerning sustainable food management in hotels, taking into account the various facets of the food supply chain. Design/methodology/approach - Several dimensions are proposed for dealing with sustainable food management, involving all aspects of food supply chains that may be relevant for hotel decision-making. Furthermore, some key criteria for creating and using indicators of different types (qualitative and quantitative) to address these various dimensions of sustainable food management are suggested. Subsequently, the proposed framework is validated with the sustainability criteria and indicators provided by the top eight hotel groups, according to the 2019 SAM Annual Corporate Sustainability Assessment. Findings - Hotels neglect a number of aspects of sustainable food management identified in the framework. The quality and the quantity of the information provided by hotels are limited. Practical implications - There is a need to improve sustainability in food management in the hotels under analysis in several areas. A comprehensive framework such as that proposed in this paper may be of great value in seeking to remedy this situation. It may also assist users of hotel services and communities in making more informed decisions. Originality/value - The proposed framework may be beneficial in advancing academic debate towards a more embracing and relevant understanding of sustainable food management in hotels and on the indicators required in this regard. Keywords Sustainability indicators, Sustainable supply chain, Food chain management, Food waste, Hotels Paper type Research pape

    Conservación de la conectividad del paisaje forestal bajo diferentes escenarios de cambio en las cubiertas del suelo

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    Managing forest landscapes to sustain functional connectivity is considered one of the key strategies to counteract the negative effects of climate and human-induced changes in forest species pools. With this objective, we evaluated whether a robust network of forest connecting elements can be identified so that it remains efficient when facing different types of potential land cover changes that may affect forest habitat networks and ecological fluxes. For this purpose we considered changes both in the forested areas and in the non-forest intervening landscape matrix. We combined some of the most recent developments in graph theory with models of land cover permeability and least-cost analysis through the forest landscape. We focused on a case of study covering the habitat of a forestdwelling bird (nuthatch, Sitta europaea) in the region of Galicia (NW Spain). Seven land-use change scenarios were analysed for their effects on connecting forest elements (patches and links): one was the simplest case in which the landscape is represented as a binary forest/non-forest pattern (and where matrix heterogeneity is disregarded), four scenarios in which forest lands were converted to other cover types (to scrubland due to wildfires, to extensive and intensive agriculture, and to urban areas), and two scenarios that only involved changes in the non-forested matrix (renaturalization and intensification). Our results show that while the network of connecting elements for the species was very robust to the conversion of the forest habitat patches to different cover types, the different change scenarios in the landscape matrix could more significantly weaken its long-term validity and effectiveness. This is particularly the case when most of the key connectivity providers for the nuthatch are located outside the protected areas or public forests in Galicia, where biodiversity-friendly measures might be more easily implemented. We discuss how the methodology can be applied to a wide range of forest landscape management situations, where both the conservation of the forest critical areas and an adequate management of the landscape matrix between them are of concern to achieve the sustainability of the ecological flows and ecosystem services at the wider forest landscape scale.La gestión de los bosques para mantener la conectividad ecológica se considera una de las estrategias clave para contrarrestar los efectos negativos provocados por el cambio climático y de los usos del suelo sobre las especies forestales. Con este objetivo, en este estudio evaluamos la posibilidad de identificar una red de elementos conectores forestales que sea robusta y eficiente ante cambios potenciales en las cubiertas del suelo que puedan afectar a las redes landde hábitats forestales y a los flujos ecológicos entre ellos. Para ello, consideramos cambios tanto en las áreas de bosque como en la matriz no arbolada del paisaje. Combinamos algunos desarrollos recientes en teoría de grafos con modelos de permeabilidad del paisaje forestal y análisis de mínimo coste. Centramos nuestro caso de estudio en el hábitat de un ave forestal (trepador azul, Sitta europaea) en Galicia (NO España). Analizamos siete escenarios de cambios de uso del suelo según sus efectos en los elementos conectores (teselas y enlaces): uno (el caso más simple) en el que el paisaje se representó como un patrón binario de bosque/no bosque (sin considerar la heterogeneidad de la matriz), cuatro escenarios en los que las teselas de bosque se transformaron en otros tipos de cubierta del suelo (matorral debido a incendios, agricultura extensiva e intensiva y zonas urbanas), y dos escenarios en los que los cambios se produjeron tan solo en la matriz no arbolada (renaturalización e intensificación). Nuestros resultados muestran que a pesar de que la red de elementos conectores para esta especie fue eficiente frente a la conversión de las teselas de hábitat forestal en diferentes tipos de cubierta, los cambios en la matriz del paisaje podrían debilitar considerablemente su validez y eficacia a largo plazo. Este es especialmente el caso dado que la mayor parte de los elementos conectores clave para el trepador azul están localizados fuera de las zonas protegidas o de los montes de utilidad pública en Galicia, donde las medidas para la conservación de la biodiversidad forestal podrían implementarse con mayor facilidad. Discutimos cómo esta metodología puede aplicarse en un amplio rango de escenarios de gestión del paisaje forestal, en los que tanto la conservación de las teselas de hábitat forestal críticas como un manejo adecuado de la matriz situada entre las mismas son de interés para conseguir la sostenibilidad de los flujos ecológicos y de los servicios de los ecosistemas en las escalas amplias en las que operan dichos procesos

    Effects on Rotational Dynamics of Azo and Hydrazodicarboxamide-Based Rotaxanes

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    © 2017 by the authors. Licensee MDPI, Basel, Switzerland. This manuscript version is made available under the CC-BY 4.0 license https://creativecommons.org/licenses/by/4.0/ This document is the Published Manuscript version of a Published Work that appeared in final form in Molecules. To access the final edited and published work see https://doi.org/10.3390/molecules22071078The synthesis of novel hydrogen-bonded [2]rotaxanes having two pyridine rings in the macrocycle and azo- and hydrazodicarboxamide-based templates decorated with four cyclohexyl groups is described. The different affinity of the binding sites for the benzylic amide macrocycle and the formation of programmed non-covalent interactions between the interlocked components have an important effect on the dynamic behavior of these compounds. Having this in mind, the chemical interconversion between the azo and hydrazo forms of the [2]rotaxane was investigated to provide a chemically-driven interlocked system enable to switch its circumrotation rate as a function of the oxidation level of the binding site. Different structural modifications were carried out to further functionalize the nitrogen of the pyridine rings, including oxidation, alkylation or protonation reactions, affording interlocked azo-derivatives whose rotation dynamics were also analyzed

    Análisis de datos de expresión con R como herramienta para el estudio de familias génicas

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    Las proteínas B-box de Arabidopsis thaliana constituyen una familia de 32 miembros (BBX1 a BBX32) que están implicadas en múltiples procesos a lo largo de toda la vida de la planta. Participan en procesos de desetiolación, floración y germinación entre otros. También, actúan en respuestas ambientales como en las respuestas a la percepción de plantas vecinas o a la salinidad. Los datos proporcionados por microarreglos y RNAseq hechos en plantas bajo diversas condiciones experimentales pueden suministrar información importante y robusta acerca de la expresión de los genes de interés y pueden servir para plantear nuevas hipótesis de trabajo. En la actualidad, la base de datos existente es extensa y variada. Los datos publicados pueden estar crudos, procesados y también de ambas formas. Como consecuencia, realizar análisis con herramientas convencionales como tablas Excel es complejo y lento, pudiendo cometer múltiples errores en los numerosos pasos del proceso. El objetivo del siguiente trabajo es analizar la familia de proteínas B-box mediante el software R en microarreglos y RNAseq de plantas en distintas condiciones experimentales.Sociedad Argentina de Informática e Investigación Operativ

    Oxidación a 1123 K de sistemas multicapa AISI 304-Ni/Al-Al2O3/TiO2 depositados mediante proyección por llama

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    The oxidation behaviour of alumina/titania (97/3, 87/13 and 60/40) ceramic coatings using a Ni-Al coupling layer was studied in a thermobalance. Both layers were deposited on an AISI 304 stainless steel base metal by the flame spray technique. The coated steel was heated from room temperature to 1,123 K at 40 K min–1, oxidized in air for 50 h, and then cooled to room temperature at 40 K min–1. The mass gain was mainly attributed to the oxidation of Ni-Al coupling layer. Kinetic laws, DW·S–1 (mg.mm–2) vs. time (hours) were close to a parabolic plot for each sample. Surface composition of ceramic top layer and the cross section of multilayer system were analysed using a wide range of experimental techniques including Scanning Electron Microscopy (SEM), equipped with a link energy dispersive X-Ray spectroscopy (EDX) and X-Ray diffraction (XRD) before and after the oxidation process. Coatings 97/3 and 87/13 presented a stable structure after flame spray deposition and they did not evolve with the oxidation process, while most of the 60/40 coating changed to a metastable structure after deposition and to a more stable structure after oxidation with high micro-cracks content. SEM and EDX microanalysis of the cross-sections showed that significant oxidation and a weak intergranular precipitation had been produced in the coupling layer and on the stainless steel base metal, respectively.El comportamiento a oxidación de recubrimientos cerámicos alúmina/titania (97/3, 87/13, 60/40) usando una capa de anclaje Ni-Al se ha estudiado mediante una termobalanza. Ambas capas se han depositado sobre un acero inoxidable AISI 304 utilizando la técnica de proyección llama (FS). El acero recubierto se ha calentado desde la temperatura ambiente hasta 1.123 K a 40 K min–1, se ha oxidado al aire durante 50 h, y luego se ha enfriado hasta la temperatura ambiente a 40 K min–1. La ganancia en masa se atribuye a la oxidación de la capa de enganche Ni-Al. La cinética DW·S–1 (mg.mm–2) vs. tiempo (horas) se ha ajustado a una ley parabólica para todas las muestras. La composición super- ficial de la capa cerámica y la sección transversal del sistema multicapa se han analizado mediante las técnicas de Microscopía Electrónica de Barrido (SEM), Espectroscopia de Energías Dispersivas de Rayos X (EDX), Difracción de Rayos X (XRD) antes y después del proceso de oxidación. Los recubrimientos 97/3 y 87/13 han presentado una estruc- tura estable tras el proceso de deposición por proyección por llama y esta estructura tampoco ha evolucionado después de la oxidación, mientras la mayor parte del recubrimiento 60/40 ha cambiado a una estructura metaestable después la deposición y finalmente ha evolucionado a una estructura más estable después de la oxidación con alto contenido de microagrietamiento. El microanálisis mediante SEM y EDX de las secciones transversales han mostrado una oxidación significativa en la capa de enganche y una débil precipitación intergranular en el material base AISI 30

    Performance of NiCrAlY Coatings Deposited by Oxyfuel Thermal Spraying in High Temperature Chlorine Environment

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    A microcrystalline Ni-22Cr-10Al-1Y (wt.%) coating was deposited on AISI 304 stainless steel by the oxyfuel thermal spray technique. The deposited coating was subjected to heat treatment to improve the microstructure characteristics and its corresponding high-temperature properties. The isothermal high-temperature corrosion behavior at 650 and 700 °C in synthetic air and in the presence of 1% Cl2 was investigated using thermogravimetric analysis, x-ray diffraction, and scanning electron microscopy with energy-dispersive x-ray spectroscopy. The results indicated that the deposited NiCrAlY coating possessed acceptable oxidation-corrosion resistance at 650 °C owing to the formation of extensive amounts of the protective oxide of Cr2O3; NiO and a lesser amount of a Cr1.12 Ni2,88 metallic phase are also formed. At 700 °C, the coating lost its protective characteristic because of the excessive consumption of thermodynamically stable phases by oxidation-chlorination process. In this case, the steel base and the coating were attacked by chlorine during the exposure time; the mass gain of the NiCrAlY coating was slightly higher and provided only a limited protection up to 11 h; thereafter, breakdown of the layer of oxides occurred and this is attributed to the formation of non-protective oxides mainly β-Fe2O3 and Fe21.33O32 and the depletion of chromium

    Análisis de datos de expresión con R como herramienta para el estudio de familias génicas

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    Las proteínas B-box de Arabidopsis thaliana constituyen una familia de 32 miembros (BBX1 a BBX32) que están implicadas en múltiples procesos a lo largo de toda la vida de la planta. Participan en procesos de desetiolación, floración y germinación entre otros. También, actúan en respuestas ambientales como en las respuestas a la percepción de plantas vecinas o a la salinidad. Los datos proporcionados por microarreglos y RNAseq hechos en plantas bajo diversas condiciones experimentales pueden suministrar información importante y robusta acerca de la expresión de los genes de interés y pueden servir para plantear nuevas hipótesis de trabajo. En la actualidad, la base de datos existente es extensa y variada. Los datos publicados pueden estar crudos, procesados y también de ambas formas. Como consecuencia, realizar análisis con herramientas convencionales como tablas Excel es complejo y lento, pudiendo cometer múltiples errores en los numerosos pasos del proceso. El objetivo del siguiente trabajo es analizar la familia de proteínas B-box mediante el software R en microarreglos y RNAseq de plantas en distintas condiciones experimentales.Sociedad Argentina de Informática e Investigación Operativ
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