3,662 research outputs found

    Characterization of Susceptible Landslide Zones by an Accumulated Index

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    In order to characterize the landslide susceptibility in the central zone of Guerrero State in Mexico, a spatial model has been designed and implemented, which automatically generates cartography. Conditioning factors as geomorphological, geological, and anthropic variables were considered, and as a detonating factor, the effect of the accumulated rain. The use of an inventory map of landslides that occurred in the past (IL) was also necessary, which was produced by an unsupervised detection method. Before the design of the model, an analysis of the contribution of each factor, related to the landslide inventory map, was performed by the Jackknife test. The designed model consists of a susceptibility index (SI) calculated pixel by pixel by the accumulation of the individual contribution of each factor, and the final index allows the susceptibility cartography to slide in the study area. The evaluation of the obtained map was performed by applying an analysis of the frequency ratio (FR) graphic, and an analysis of the receiver operating characteristic (ROC) curve was developed. Studies like this can help different safeguarding institutions, locating the areas where there is a greater vulnerability according to the considered factors, and integrating disaster attention management or prevention plans

    Influence of climate change on the flowering of temperate fruit trees

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    It is well known that winter chilling is necessary for the flowering of temperate trees. The chilling requirement is a criterion for choosing a species or variety at a given location. Also chemistry products can be used for reducing the chilling-hours needs but make our production more expensive. This study first analysed the observed values of chilling hours for some representative agricultural locations in Spain for the last three decades and their projected changes under climate change scenarios. Usually the chilling is measured and calculated as chilling-hours, and different methods have been used to calculate them (e.g. Richarson et al., 1974 among others) according to the species considered. For our objective North Carolina method (Shaltout and Unrath, 1983) was applied for apples, Utah method (Richardson et al. 1974) for peach and grapevine and the approach used by De Melo-Abreu et al. (2004) for olive trees. The influence of climate change in temperate trees was studied by calculating projections of chilling-hours with climate data from Regional Climate Models (RCMs) at high resolution (25 km) from the European Project ENSEMBLES (http://www.ensembles-eu.org/). These projections will allow for analysing the modelled variations of chill-hours between 2nd half of 20C and 1st half of 21C at the study locations

    Influence of the Water Vapour Permeability of Airtight Sheets on the Behaviour of Facade

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    The air-tightness of the thermal envelope of buildings is one of the measures to reduce their energy demands in order to achieve global warming reduction targets. To this end, airtight sheets with different water vapour permeability characteristics are used. The different products studied are highly dispersed in terms of equivalent air thickness values, leading to confusion. After the analysis carried out, it is concluded that all airtight sheets are vapour barriers. To clarify whether or not these sheets are necessary as vapour barriers, a condensation analysis was carried out on 13 different facades for 3 climate zones with severe winters as defined in Spanish regulations. The results reveal that interstitial condensation occurs in only 7 of the 39 case studies, with the traditional facades of brickwork with render causing the greatest problems if the appropriate products are not used. In these cases, airtight sheets with water vapour barrier characteristics must be applied on the interior face of the insulating material. In all other cases (32), the airtight sheets must be permeable to water vapour if it is looked for a more breathable wall to water vapour and a better control of the interior humidity conditions

    Estudio comparativo de distintas técnicas analíticas (espectroscopía de NIR y RMN y extracción mediante Soxhlet) para la determinación del contenido graso y de humedad en aceitunas y orujo de Jaén.

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    The suitability of two analytical techniques ( viz. near infrared spectroscopy and nuclear magnetic resonance spectroscopy) for the determination of moisture and fat content of olives and pomace was determined. The results obtained from the two techniques were similar in terms of accuracy and precision to those provided by the official method, which is based on Soxhlet extraction. On the other hand, the proposed methods involve less intensive sample handling, use reagents and solvents more sparingly and are faster than the official method. This allows for their adoption as standard laboratory methods for the determination of analytical parameters in both olives and pomace.Se ha estudiado la viabilidad de dos métodos analíticos (espectroscopía de infrarrojo cercano y espectroscopía de resonancia magnética nuclear) para la determinación de humedad y contenido graso en aceitunas y orujo. Los resultados obtenidos son similares, en términos de precisión y exactitud, con los conseguidos usando el Método Oficial basado en la extracción Soxhlet. Las ventajas que presentan ambos métodos con respecto al Oficial (reducción de la manipulación de la muestra, reducción del consumo de reactivos y disolventes, y disminución del tiempo de análisis) hace que se puedan proponer como métodos normalizados de un laboratorio para la determinación de ambos parámetros en aceitunas y orujo

    Antifungal ativity against Botryosphaeriaceae fungi of the hydro-methanolic extract of Silybum marianum capitula conjugated with stevioside

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    Silybum marianum (L.) Gaertn, viz. milk thistle, has been the focus of research efforts in the past few years, albeit almost exclusively restricted to the medicinal properties of its fruits (achenes). Given that other milk thistle plant organs and tissues have been scarcely investigated for the presence of bioactive compounds, in this study, we present a phytochemical analysis of the extracts of S. marianum capitula during the flowering phenological stage (stage 67). Gas chromatography–mass spectroscopy results evidenced the presence of high contents of coniferyl alcohol (47.4%), and secondarily of ferulic acid ester, opening a new valorization strategy of this plant based on the former high-added-value component. Moreover, the application of the hydro-methanolic extracts as an antifungal agent has been also explored. Specifically, their activity against three fungal species responsible for the so-called Botryosphaeria dieback of grapevine (Neofusicoccum parvum, Dothiorella viticola and Diplodia seriata) has been assayed both in vitro and in vivo. From the mycelial growth inhibition assays, the best results (EC90 values of 303, 366, and 355 μg·mL−1 for N. parvum, D. viticola, and D. seriata, respectively) were not obtained for the hydroalcoholic extract alone, but after its conjugation with stevioside, which resulted in a strong synergistic behavior. Greenhouse experiments confirmed the efficacy of the conjugated complexes, pointing to the potential of the combination of milk thistle extracts with stevioside as a promising plant protection product in organic Viticulture

    The nuclear and extended infrared emission of the Seyfert galaxy NGC 2992 and the interacting system Arp 245

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    We present subarcsecond resolution infrared (IR) imaging and mid-IR spectroscopic observations of the Seyfert 1.9 galaxy NGC 2992, obtained with the Gemini North Telescope and the Gran Telescopio CANARIAS (GTC). The N-band image reveals faint extended emission out to ~3 kpc, and the PAH features detected in the GTC/CanariCam 7.5-13 micron spectrum indicate that the bulk of this extended emission is dust heated by star formation. We also report arcsecond resolution MIR and far-IR imaging of the interacting system Arp 245, taken with the Spitzer Space Telescope and the Herschel Space Observatory. Using these data, we obtain nuclear fluxes using different methods and find that we can only recover the nuclear fluxes obtained from the subarcsecond data at 20-25 micron, where the AGN emission dominates. We fitted the nuclear IR spectral energy distribution of NGC 2992, including the GTC/CanariCam nuclear spectrum (~50 pc), with clumpy torus models. We then used the best-fitting torus model to decompose the Spitzer/IRS 5-30 spectrum (~630 pc) in AGN and starburst components, using different starburst templates. We find that, whereas at shorter mid-IR wavelengths the starburst component dominates (64% at 6 micron), the AGN component reaches 90% at 20 micron. We finally obtained dust masses, temperatures and star formation rates for the different components of the Arp 245 system and find similar values for NGC 2992 and NGC 2993. These measurements are within those reported for other interacting systems in the first stages of the interaction.Comment: 20 pages, 12 figures, accepted by MNRA

    A Substantial Amount of Hidden Magnetic Energy in the Quiet Sun

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    Deciphering and understanding the small-scale magnetic activity of the quiet solar photosphere should help to solve many of the key problems of solar and stellar physics, such as the magnetic coupling to the outer atmosphere and the coronal heating. At present, we can see only ∼1{\sim}1% of the complex magnetism of the quiet Sun, which highlights the need to develop a reliable way to investigate the remaining 99%. Here we report three-dimensional radiative tranfer modelling of scattering polarization in atomic and molecular lines that indicates the presence of hidden, mixed-polarity fields on subresolution scales. Combining this modelling with recent observational data we find a ubiquitous tangled magnetic field with an average strength of ∼130{\sim}130 G, which is much stronger in the intergranular regions of solar surface convection than in the granular regions. So the average magnetic energy density in the quiet solar photosphere is at least two orders of magnitude greater than that derived from simplistic one-dimensional investigations, and sufficient to balance radiative energy losses from the solar chromosphere.Comment: 21 pages and 2 figures (letter published in Nature on July 15, 2004

    Cap al desenvolupament de circuits multifuncionals utilitzant dispositius emergents basats en carboni

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    Durant els últims anys la demanda de sistemes de comunicació robustos ha anat en augment com a resposta a les necessitats de la població per més i millors opcions de connectivitat. Les tecnologies de semiconductors emergents, com per exemple dispositius a base de carboni, han sorgit com a alternativa a curt termini per incrementar els límits d'acompliment de circuits integrats. En particular, els nanotubs de carboni (CNTs) apareixen com a una opció per a ser utilitzats en el canal de transistors d'efecte de camp (FETs) de nova generació, tot obrint la porta per ser utilitzats en el disseny de circuits de radiofreqüència, explotant les característiques intrínseques dels CNTs, com la ambipolaritat, per dissenyar circuits multifuncionals d'alt acompliment.Durante los últimos años la demanda de sistemas de comunicación robustos ha ido en aumento como respuesta a las necesidades de la población por más y mejores opciones de conectividad. Las tecnologías de semiconductores emergentes, como por ejemplo dispositivos a base de carbono, han surgido como una alternativa en el corto plazo para incrementar los límites de desempeño de circuitos integrados. En particular, los nanotubos de carbono (CNTs) aparecen como una opción para ser utilizados en el canal de transistores de efecto de campo (FETs) de nueva generación, abriendo la puerta para ser utilizados en el diseño de circuitos de radiofrecuencia, explotando las características intrínsecas de los CNTs, como la ambipolaridad, para diseñar circuitos multifuncionales de alto desempeño.During the last years, the claim of high-performance communication systems has increased as a result of the requirements of the population for more and better connectivity options. Emerging semiconductor technologies, e.g., carbon-based devices, have emerged as a short-term alternative to increase the performance limits of the integrated circuits. In particular, carbon nanotubes (CNTs) appeared as an option to use on the channel of new-generation field-effect transistors (FETs). Opening the door to being used during the design of radiofrequency circuits, using the intrinsic characteristics of the CNTs, such as ambipolarity, in order to design high-performance multifunctional circuits

    Influence of annealing conditions on formation of regular lattices of voids and Ge quantum dots in amorphous alumina matrix

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    In this work, the influence of air pressure during the annealing of Ge quantum dot (QD) lattices embedded in an amorphous Al2O3 matrix on the structural, morphological and compositional properties of the film is studied. The formation of a regularly ordered void lattice after performing a thermal annealing process is explored. Our results show that both the Ge desorption from the film and the regular ordering of the QDs are very sensitive to the annealing parameters. The conditions for the formation of a void lattice, a crystalline Ge QD lattice and a disordered QD lattice are presented. The observed effects are explained in terms of oxygen interaction with the Ge present in the film.This study has been partially funded through the projects (i) FEDER funds through the COMPETE program ‘Programa Operacional Factores de Competitividade’ and by Portuguese funds through the Portuguese foundation for Science and Technology (FCT) in the frame of the project PTDC/FIS/70194/2006 and PEst-C-FIS/UI607/2011–2012; (ii) ELETTRA Synchrotron Radiation Center through the European Community’s Seventh Framework Programme (FP7/2007–2013) under grant agreement no 226716. SRCP is grateful for financial support through the FCT grant SFRH/BPD/73548/2010 and JMS is grateful for financial support through the Spanish CSIC JAE-DOC program. MB acknowledges support from the Croatian Ministry of Science, Higher Education and Sport (project number 098-0982886-2859).We thank Dr Anabela Rolo and Engineer Jos´e Santos for all the valuable discussions and the sample preparation
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