ESTUDIO ECOLÓGICO DE VITREA( VITREA) CONTRACTA (WESTERLUND, 1871) (MOLLUSCA: GASTROPODA: PULMONATA: STYLOMMATOPHORA) EN EL NOROESTE DE LA PENINSULA IBÉRICA

The relationships of Vitrea (Vitrea) contracta (Westerlund, 1871) with 3 biotopes and with 20 edaphic factors, in Asturias, León, Zamora and Salamanca (northwestern Iberian Peninsula) have been studied. The results showed that V.contracta appear in forest mairily, and prefer acid soils (pH in KC1 4.4-7.0), with medium to high values of nitrogen (0.23-1.4 %) and clay (1 1.6-55.0 %), high coarse silt values (1 1.6-37.0 %) and low coarse sand values (1 .O-21 .O %).Se estudia la relación de Vitrea (Vitrea contracta (Westerlund, 1871) con 3 biotopos y 20 factores edáficos, en Asturias, León, Zamora y Salamanca (noroeste de la Península Ibérica). Los resultados obtenidos indican que V.contracta se encuentra principalmente en arbolados o zonas boscosas, y tiene preferencia por suelos ácidos (pH de suelo en KC14.4-7.0), con valores medios-altos de nitrógeno (0.23-1.4 %) y arcilla (1 1.6- 55.0 %), altos de limo grueso (11.6-37.0 %) y bajos de arena gruesa (1.0-21.0 %)

Molybdenite as a rhenium carrier : first results of a spectroscopic approach using synchrotron radiation

The chemical and physical properties of rhenium render it a highly demanded metal for advanced applications in important industrial fields. This very scarce element occurs mainly in ores of porphyry copper-molybdenum deposits associated with the mineral molybdenite, MoS2, but it has also been found in granite pegmatites and quartz veins as well as in volcanic gases. Molybdenite is a typical polytype mineral which crystal structure is based on the stacking of [S-Mo-S] with molybdenum in prismatic coordination by sulphide anions; however, it is not yet clearly established if rhenium ions replace Mo4+ cations in a disordered way or else, if such replacement gives rise to dispersed nanodomains of a rhenium-rich phase. As a contribution to clarify this question, an X-ray absorption spectroscopy (XANES) study using synchrotron radiation was performed at the Re L3-edge of rhenium-containing molybdenite samples. Obtained results are described and discussed supporting the generally accepted structural perspective that rhenium is mainly carried by molybdenite through the isomorphous replacement of Mo, rather than by the formation of dispersed Re-specific nanophase(s)

Health and power: a study about hegemonical and subaltern speeches in multicultural contexts

The difficulty of communication between health professionals and popular communities are well known and appears mainly in the inefficacy of the treatments such as the official medicine prescribes them, as well as in the dissatisfaction, on the part of the users, with its results. In this article, we analyze this situation, placing in relief the ethical importance of listening to, for the professionals of the health, the speeches and extra-scientific knowledge on the illness and the health affirmed by such communities. Listening most sensible will be able to give visibility to the elements that hinder the communication accomplish, providing the restitution of the reciprocity in the communication, which means the refusal and the transformation of the relations of subalternity established there.A dificuldade de comunicação entre profissionais de saúde e as comunidades populares é notória e se expressa principalmente na ineficácia dos tratamentos tal como os prescreve a medicina oficial, assim como no descontentamento, por parte dos usuários, com os seus resultados. Este artigo refletir sobre tal situação, colocando em relevo a importância ética da escuta, pelos profissionais da saúde, dos discursos e saberes extra-científicos sobre a doença e a saúde afirmados por tais comunidades. A escuta mais sensível poderá dar visibilidade aos elementos que impedem a comunicação efetiva, proporcionando a restituição da reciprocidade comunicativa, o que significa a recusa e a transformação das relações de subalternidade aí estabelecidas

Selenium speciation in waste materials from an exhausted Iberian Pyrite Belt mine

Selenium is an essential nutrient for humans, animals and microorganisms, but it becomes toxic at concentrations slightly above the nutritional levels. This naturally occurring trace element can be released to the environment from various anthropogenic sources such as mining, agricultural, petrochemical and industrial processes and its toxicity is developed along a complex cycle involving adsorption by soil components and subsequent accumulation by plants. In the environment, selenium can occur in several oxidation states ranging from selenide (Se=) to elemental selenium (Se0), selenite (Se4+) and selenate (Se6+). Selenium contents above 900 ppm were recently assigned in mine wastes from the sulphur factory at the São Domingos exhausted pyrite mine exploited in the Iberian Pyrite Belt (south Portugal) since Roman times until 1966. Aiming at a sustainable remediation of this mining site, an X-ray absorption spectroscopy study using synchrotron radiation, combined with X-ray diffraction, was undertaken to clarify the speciation state of selenium and the nature of Se-carrier phase(s). The results show that selenium does not significantly replace sulphur under the form of selenate in the dominant sulphate phases and occasionally remains as a substituting selenide anion in debris of the original sulphides present in the mine waste materials

Relationships between terrestrial gastropod distribution and soil properties in Galicia (NW Spain)

Abstract This study investigated the influence of edaphic factors on the distribution of 17 terrestrial gastropod species over a large area of the northwest Iberian Peninsula. A total of 498 gastropod/soil samples were obtained, and a total of 19 edaphic variables determined. The resulting data matrix was analysed by detrended canonical correspondence analysis (DCCA). Our results indicate that the gastropods of the study area can be grouped on two types of criteria: first, chemical criteria (notably pH, cation exchange capacity, and Al content), and secondly physical criteria (notably texture and moisture content). In view of distribution with respect to these factors, two well-defined groups can be identified: one comprising Acanthinula aculeata, Euconulus fulvus, Punctum pygmaeum, Columella aspera and Oxychilus alliarius preferring coarse-textured acid soils, the other comprising Cochlicopa lubrica, Vertigo pygmaea, Zonitoides excavatus, Carychium tridentatum, Deroceras reticulatum and Deroceras lombricoides preferring wetter, finer-textured, less acid soils. Arion intermedius and Ponentina subvirescens were in general indifferent to the edaphic factors considered