11 research outputs found

    Laumontita y Prehnita en la formación submarina del Complejo Basal de La Palma, Islas Canarias

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    Una zeolita perteneciente a la formación volcánica submarina del Complejo Basal de la isla de La Palma se ha caracterizado tanto por microsonda electrónica como por microscopía óptica, difracción de Rayos X, análisis térmico diferencial, termogravimetría y espectroscopía de infrarrojos. Los datos analíticos obtenidos confirman la identidad de esta zeolita como laumontita, que hasta el presente no se había citado en la formación antes citada. Asociada a la laumontita se encuentra también el mineral prehnita. Se ha construido un diagrama de actividad para los tres componentes: aSiO4H4, aCA++ y aH+ en el intervalo de temperatura de los 25 a los 300ºC. En él se representan los campos de estabilidad de heulandita, prehnita, laumontita, calcita y cuarzo. Este diagrama, junto con los diagramas de solubilidad de prehnita y laumontita nos ha permitido estimar las condiciones de formación de la paragénesis laumontita-prehnita-calcita existente en las muestras estudiadas

    Mineralogía y geoquímica de las sienitas nefelínicas de Montaña Blanca-Esquinzo, NO de Fuerteventura (Islas Canarias)

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    Nepheline-syenites from the northern, Montaña Blanca-Esquinzo sector of the Basal Complex in the island of Fuerteventura (Canary Islands) are the most differentiated rocks belonging to the alkaline-carbonatitic association in this area. These nepheline-syenites are peculiar when compared with their counterparts in other alkaline-carbonatitic bodies, due to their lack of hydrous minerals (amphiboles, micas) and their strong depletions in incompatible elements. In this work, we present both mineralógica! and geochemical data on these rocks in order to obtain information about their origin and relationship with the ultramafic and mafic terms (clinopyroxenites and melteigites-ijolites) of the alkaline silicate rocks belonging to this association of the Basal Complex. These data suggest that the Montaña Blanca-Esquinzo nepheline-syenites are the products of extensive fractionation + accumulation of the same magma that gave rise to the clinopyroxenites and melteigites-ijolites

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Escolecita de aglomerados basálticos del complejo basal de Fuerteventura (Islas Canarias)

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    Se caracteriza por análisis químico, microscopía óptica, difracción de Rayos X, análisis térmico diferencial, termogravimetría y espectroscopía de infrarrojos, una zeolita fibrosa perteneciente a la formación volcánica aglomerática del Complejo Basal de la isla de Fuerteventura. Los datos analíticos obtenidos confirman la identidad de esta zeolita fibrosa como escolecita. El análisis químico del mineral pone de manifiesto un elevado contenido en sodio, superior a los que aparecen en la bibliografía para distintas escolecitas y próximo al de mesolita. Los diagramas de difracción de rayos X y análisis térmico diferencial son intermedios a los correspondientes a mesolita y escolecita. Sin embargo, las propiedades ópticas del mineral, la curva termogravimétrica y el espectro de infrarrojo son concluyentes, confirmando la identidad de esta zeolita fibrosa como escolecita

    Isotope geochemistry and FOZO mantle component of the alkaline-carbonatitic association of Fuerteventura, Canary Islands, Spain

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    Carbonatites are very rare in oceanic environments, where they have been reported only at the Canary and Cape Verde islands in the Atlantic Ocean. In the Canary archipelago, calciocarbonatites occur only on the island of Fuerteventura, in clear spatial and temporal association to alkaline silicate rocks, ranging from ultramafic to salic, and comprising alkaline clinopyroxenites, melteigites–ijolites–urtites, nepheline-bearing gabbros and nepheline–syenites, together with their volcanic equivalents. Selected isotopic (Sr, Nd and Pb) data from representative samples of this alkaline–carbonatitic association show a very estricted range of isotopic compositions, with those of the calciocarbonatites overlapping those of the alkaline silicate rocks. Despite the fact that all these rocks display cumulate textures and cover a wide range of SiO2 and Sr, Nd, Pb contents, initial isotopic compositions are approximately constant and mantle-like, indicating that evolution of the alkaline–carbonatitic association of Fuerteventura must have taken place in the absence of crustal contamination processes. Regarding the mantle source for the alkaline–carbonatitic association, its depleted initial Sr (87Sr/86Sr=0.7032–0.7036) and Nd (143Nd/144Nd=0.5128–0.5129) compositions, fall on the same trend as the East African young (<40 Ma) carbonatites. In 143Nd/144Nd and 87Sr/86Sr vs. 206Pb/204Pb diagrams, the alkaline–carbonatitic association of Fuerteventura shows FOZO compositions for Sr and Nd, and slightly higher (towards HIMU) Pb compositions. Furthermore, these data fit the projection of the mantle plane defined by Sr, Nd and Pb isotopic compositions of the DMM, HIMU and EMI components, this fit not being found in sources containing crustal components. In view of this, we propose that the alkaline–carbonatitic association of Fuerteventura was derived mainly from a heterogeneous mantle plume with a deep-seated (FOZO) signature, mixed with HIMU component
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