The spatial damping of magnetohydrodynamic waves in a flowing partially ionised prominence plasma

Solar prominences are partially ionised plasmas displaying flows and oscillations. These oscillations show time and spatial damping and, commonly, have been explained in terms of magnetohydrodynamic (MHD) waves. We study the spatial damping of linear non-adiabatic MHD waves in a flowing partially ionised plasma, having prominence-like physical properties. We consider single fluid equations for a partially ionised hydrogen plasma including in the energy equation optically thin radiation, thermal conduction by electrons and neutrals, and heating. Keeping the frequency real and fixed, we have solved the obtained dispersion relations for the complex wavenumber, k, and have analysed the behaviour of the damping length, wavelength and the ratio of the damping length to the wavelength, versus period, for Alfven, fast, slow and thermal waves.Comment: 28 pages, 9 figure

Un reto en la fundamentación del conocimiento escolar. Propuesta de contextualización de los procesos y técnicas de la Ciencia en la Educación Científica Básica.

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Geochemical clistribution of An in granites with locle mineralizations in As, W ancl Au (NW of Salamanca)

[Resumen] Ante las pruebas de la existencia de altas incidencias de cáncer de próstata en una zona de la provincia de Salamanca y habiendo descartado los factores etiológicos más comunes como su posible causa (MAYOR ARENAL, 1988), se concluye que el único factor de riesgo posible se debería a la existencia de algún factor carcinógeno ambiental. Se realizó una prospección geoquímica de Cd en esta zona dada la relación etiológica de este elemento con dicha enfermedad y se ha constatado que efectivamente existe una anomalía de Cd en los sedimentos de arroyo, que no se corresponde con actividades antropogénicas, sino que son anomalías regionales de los contenidos propios de este elemento en el sustrato, evidenciándose así como potencial factor de riesgo los contenidos de Cd en los suelos desarrollados sobre rocas anómalas en dicho elemento.[Abstract] A high ineidence of prostate cancer has been observed in certain areas of the province of Salamanca. Spain. Mter ruling out the most common etiological factors as the cause (MAYOR ARENAL, 1988) it is concluded that the only possible risk factor must be due to the presence of some environmental carcinogen. In view of the etiological relationship between Cd and the patological state, a study was carried out on the geochemistry of this element in this area. Anomalous amounts of Cd were found in stream sediments and it was observed that this anomaly does not correspond to human activity but rather to high regional amounts of cadmium in the substrate. Thus, the contents of Cd in soils developed over substrates containing naturally-ocurring anomalous amounts of cadmiun should be considered as a real new risk factor

Interaction of dexamethasone and montmorillonite

3 pages, 1 figure, 7 references.-- Congreso celebrado del 7-10 septiembre 1987 en Sevilla, España.-- EUROCLAY'87.Clay-drug interactions have been widely studied during the last decade. However, the reaction mechanisms responsible of these interactions only have been elucidated in sorne cases (1,2), most of them when cationic drugs are ínvolved. Neutral molecules are known to interact with clays by physical adsorption (3), and/or by hydrogen bonding (4). Dioxin is adsorbed onto montmorillonite by a reversible adsorption mechanism (5) and degrades by acid-catalyzed hydrolisis. The mechanism of ad sorption and degradation of the neutral steroid hydrocortisone by palygorskite and sepio1ite has be en recently studied (6,7). Two types of ferric iron present in these clays may be responsible for the different degradation rates of hydrocortisone.Peer reviewe

Sustainable tourism research towards twenty-five years of the journal of sustainable tourism

© 2018 Advances in Hospitality and Tourism Research. All Rights Reserved. The Journal of Sustainable Tourism (JOST) is a main journal in 'Geography, Planning and Development'. The concept of sustainable tourism has gained importance over time. This paper presents a general overview of the journal over its lifetime by using bibliometric indicators. Moreover, in order to establish the position of sustainable tourism research, this paper identifies the trends in research through bibliometric studies. It uses the Scopus database to analyse the bibliometric data. This analysis includes key issues such as the publication and citation structure of the journal; the most cited articles; the leading authors, institutions, and countries in the journal; and the keywords that are most often used. This paper also uses the visualization of similarities to graphically map the bibliographic material. This analysis provides further insights into how JOST links to other journals and how it links researchers across the globe. These results indicate that JOST is one of the leading journals in the areas where the journal is indexed, with a wide range of authors from institutions and countries from all over the world publishing in it. The results of the current study can provide insights into topics related to sustainable tourism that can be researched in the future

Un reto en la fundamentación del conocimiento escolar. Propuesta de contextualización de los procesos y técnicas de la Ciencia en la Educación Científica Básica.

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Los cargos eclesiásticos y religiosos como estrategia de recuperación del poder de los descendientes de Pedro I de Castilla.

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Partial protection against collagen antibody-induced arthritis in PARP-1 deficient mice

Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear DNA-binding protein that participates in the regulation of DNA repair and maintenance of genomic integrity. In addition, PARP-1 has a role in several models of inflammation disease, where its absence or inactivation confers protection. The aim of this study was to analyze the impact of selective PARP-1 suppression in collagen antibody-induced arthritis. We show that PARP-1 deficiency partially reduces the severity of arthritis, although the incidence of disease was similar in control and deficient mice. Decreased clinical scores were accompanied by partial reduction of histopathological findings. Interestingly, quantitative real-time PCR and ELISA analysis revealed that the absence of PARP-1 down-regulated IL-1β and monocyte chemotactic protein 1 expression in arthritic joints whereas tumor necrosis factor-α transcription was not impaired. Our results provide evidence of the contribution of PARP-1 to the progression of arthritis and identify this protein as a potential therapeutic target for the treatment of rheumatoid arthritis