1,419 research outputs found

    La eficacia erosiva de la acción nival y su relación con la herencia geomorfológica: macizo de Peñalara, Sistema Central

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    [Resumen] [Abstract] An automatic station for monitoring bedload transport has been installed in a gravel-bed river. The station has two slot samplers with the pressure-pillow system (Birbeck-type) that allow a continuous measurement of bedload transport. The paper shows the bedload sampler operation, the load tests and the first results obtained. It is the first time that bedload transport is registered continuously in a river of the Iberian Peninsula.[Abstract] This article examines how snow plays a role in current erosive processes in a high mountain area (1800-2400 m a.s.l.) known as Peñalara, located in Spain's Central Range (40º 50' N; 3º 58' W). Snow depth and the movement of selected blocks at each site were recorded from October 1990 to June 1995. The relationship among late-lying snowpatches, geomorphologic heritage and current erosive processes was deternúned

    Enhancement of flavour properties in wines using sequential inoculations of non-Saccharomyces (Hansenula and Torulaspora) and Saccharomyces yeast

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    In order to produce wines with greater complexity of aroma and taste, fermentations were carried out by sequential inoculation of non-Saccharomyces (Hansenula anomala and Torulaspora delbrueckii) and Saccharomyces cerevisiae yeasts in 'Airén' variety white grape musts. The wines made by sequential inoculation had a higher pH and higher levels of acetates, compounds that supply a fruity note. The wines inoculated with Hansenula anomala presented a lower concentration of lineal alcohols and thioalcohols, which are respectively responsible for herbaceous and cooked notes. The fermentations performed by sequential inoculation of Torulaspora delbrueckii and Saccharomyces cerevisiae produced wines with lower levels of volatile acidity, acetaldehyde and carbonyl compounds. In preference tasting, the 'Airén' wines obtained by co-inoculation with the species Hansenula anomala scored highest for their sensory qualities and were particularly appreciated for their floral and/or fruity notes

    La obturación de valles por procesos de ladera: el origen de La Vega de Metztitlan (México)

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    [Resumen] En las estribaciones de la Sierra Madre Oriental (México) se localiza el lago de Metztitlán y la vega del mismo nombre. Su origen se debe a la obturación del valle por un importante deslizamiento y posteriormente un desprendimiento. En este trabajo se exponen los primeros resultados del estudio geomorfológico, se aporta una cartografía de detalle y se propone una primera explicación de la evolución del área.[Abstract] The lake and valley of Metztilán is located in Sierra Madre Oriental range (Mexico). Its origin is due to the slope collapse after great rockslide. This paper exposes the firsts geomorphologic analysis of the feature, and includes and detailed geomorphologic map. A different evolution phases is determined

    Perception of employers and employees regarding the attitude of businesses toward the environment: a qualitative analysis

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    Commitment and involvement from the different members of an organization are two key elements for an organization to achieve its environmental excellence. Firstly, businesses are aware of the close relationship between their activities and the environment, for they are not only polluting agents but also agents with the capacity to reduce adverse environmental impacts. Secondly, the fact that employees can play a relevant role in terms of the socially responsible measures to be taken by organizations has started to become an irrefutably important issue. This piece of research is intended to help gain knowledge concerning the attitude of the two main actors in productive activity toward the environmental, that is, employers and employees; as well, this research intends to identify factors determining behaviour towards the environmental. For this, we have gathered the ideas and assessments contained in the discourse of a group of small and medium-sized businesses, large company owners and officers, employees, and work related risk prevention representatives. Qualitative work consisted of in-depth interviews and the creation of discussion groups

    Investigating Piezochromic Properties of πconjugated Materials: a combined Raman and DFT Study

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    Π-conjugated materials have been studied for decades due to their great interest in organic electronics. Among them, piezochromic materials, which exhibit color changes resulting from external pressure or mechanical grinding, become very attractive from a scientific viewpoint owing to their potential applications as pressure-sensing and opticalrecording systems1. The main target of the present work is to develop a joint experimental and theoretical approach able to deliver crucial information for the understanding of the structural effects causing piezochromic changes. To this end, we will focus our attention on two families of -conjugated materials with potential application as sensors. The first one is a family of 9,10-Bis((E)-n(pyrid-2-yl)vinyl) anthracene, BPnVA (n=2 orto-,3 metha- and 4 para-) compounds, see Figure 1. Interestingly, these three compounds with varying position of the nitrogen on the external pyridyl group exhibit different molecular packing modes. Grinding and the application of external pressure on the powder also led to a strong change in their photoluminescence color.2 The second familiy is based on the N,N’-Bis-Boc-3,3’-di(pyren-1yl)-2,2’-biindole compound (compound 1c in Figure 1) which also shows photoluminescence under pressure application. However, the molecular packing induced by this phenomenon is still under study 3. In both cases, it will be also very interesting to determine how temperature affects the vibrational structure of these systems.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Female counsellors in the Spanish multinational listed companies (2012-2014)

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    One of the most important corporate governance controls widely studies the role performed by the board of directors and its consequences on the financial performance of companies. Different approaches analyse how a firm can improve its financial future and today parity on boards of directors represents a new research line. The presence of female counsellors may depend on legal and cultural approaches. As the institutional theory establishes, firms must be adapted to the countries where they operate in order to success when accessing financial markets. In this respect, this paper ads a new line of research based on whether a listed company operates in multiple countries or not and analyses the linkage between the multinational character of a company, the gender diversity of the board and the financial 2 performance of the firm. This paper focuses on Spain, which could be ground-breaking on female presence on boards, as Norway is, but only follow light recommendations. The method used is simple regression analysis. The results show that the multinational characteristic of listed companies has no effect on gender diversity but that gender has a negative relation with the financial performance of these firms. Our study also opens various lines of future research

    Redes neuronales artificiales en el control de procesos por variables: aplicación en la fabricación de tableros de partículas

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    Artificial neural networks are an efficient tool for modelling production control processes using data from the actual production as well as simulated or design of experiments data. In this study two artificial neural networks were combined with the control process charts and it was checked whether the data obtained by the networks were valid for variable process control in particleboard manufacture. The networks made it possible to obtain the mean and standard deviation of the internal bond strength of the particleboard within acceptable margins using known data of thickness, density, moisture content, swelling and absorption. The networks obtained met the acceptance criteria for test values from non-standard test methods, as well as the criteria for using these values in statistical process control.Las redes neuronales artificiales son una herramienta eficaz para el modelado de los procesos de control de producción, tanto partiendo de datos de la propia producción como de datos simulados o procedentes de diseños de experimentos. En este estudio se han combinado dos redes neuronales artificiales con los gráficos de control de procesos y se ha comprobado si los datos obtenidos con ellas eran válidos para el control de producción por variables en la fabricación de tableros de partículas. Las redes han permitido obtener valores de la media y la desviación típica de la cohesión interna del tablero de partículas dentro de unos márgenes aceptables a partir de datos conocidos de espesor, densidad, contenido de humedad, hinchazón y absorción. Las redes obtenidas han cumplido con los requisitos de aceptación de valores de ensayo por métodos alternativos al normalizado y con los requisitos impuestos para su utilización en el control estadístico de procesos

    Electronic transport and vibrational modes in the smallest molecular bridge: H2 in Pt nanocontacts

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    We present a state-of-the-art first-principles analysis of electronic transport in a Pt nanocontact in the presence of H2 which has been recently reported by Smit et al. in Nature 419, 906 (2002). Our results indicate that at the last stages of the breaking of the Pt nanocontact two basic forms of bridge involving H can appear. Our claim is, in contrast to Smit et al.'s, that the main conductance histogram peak at G approx 2e^2/h is not due to molecular H2, but to a complex Pt2H2 where the H2 molecule dissociates. A first-principles vibrational analysis that compares favorably with the experimental one also supports our claim .Comment: 5 pages, 3 figure
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