Composition and Petrologic significance of Biotites and muscovites from the granitoids of the Boal-Los Ancares Metamorphic Belt (Westasturian Leonese Zone)

[Resumen] Las biotitas de los granitoides peralumínicos de la banda metamórfica Boal-Los Ancares se sitúan en el dominio de las biotitas s.s. con contenidos en Aliv que socilan entre 2.3 y 2.65 Yvalores de Fe/Fe + Mg entre 0.42 y 0.85. La variación composicional está controlada esencialmente por mecanismos de sustitución cati6nicaacoplada. La sustitución 3(R2+ti=2Alvi5+Ovi es más eficaz que la sustitución Al-Tschermak. La entraa3. de Ti en posiciones octaédricas está controlada por la sustitución 2Alvi=(Ti4+)vi +(R2+ Ji. La composición de las biotitas en base a sus contenidos en Al y Mg permite diferenciar tres grupos de granitoides, en concordancia con su mineralogía y composición de roca total. La variación composicional de la moscovita se produce principalmente a través de las sustituciones fengítica y paragonítica. El contenido máXimo en molécula cela~donítica es de 25 0A» Yel contenido máXimo en molécula paragonítica es de 12 %. Ni los caracteres texturales ni la composición química de este mineral constituyen un criterio definitivo en muchos casos para establecer su formación en el estadio magmático del sistema o bien en estadios posteriores. La composición de la moscovita en leucogranitos y aplitas sin biotita muestra notables particularidades con relación a la composición de este mineral en granitos de dos micas. Estas diferencias son manifiestas en las proporciones Ti:Mg:Na y Ti:Fe:Mg, las cuales muestran una buena correlación con algunos parámetros composicionales de roca total.[Abstract] Biotites from the peraluminous granitoids of the Boal-Los Ancares metamporphic band plot in the field ofbiotites s.s. with Aliv contents between 2.3 and 2.65 and Fe/Fe + Mg values ranging from 0.42 to 0.85. Compositional variation is basically controlled by coupled substitutional mechanisms. Substitution 3(R2+Yi =2Alvi+(Yi is more efficient than the Al-Tschermak substitution. Ti enters the octahedral sites via the 2Alvi = (Ti4+)vi+(R2+Yi substitution. The composition of biotites on the basis of Al and Mg contents pfudiscriminates three granitoid groups, this in agreement with their respective mineralogical composition and whole rock chemistry. Muscovite compositional variation is essentially due to the phengitic and paragonitic substitutions. The maxímum celaduníte content is 25 O/o and the maximum paragonite content is 12 %. Neither textural criteria nor chemical compositiori consitute unequivocal criteria for establishing the magmatic or submagmatic origin of the studied muscovites. Muscovite composition in biotite-free leucogranites and aplites shows distinctive features with respect to two-mica granites. This is particularly noticeable in the Ti:Mg:Na and Ti:Fe:Mg ratios, which correlate well with sorne whole rock compositional parameter

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In this study we report laser ablation–inductively coupled plasma–mass spectrometer U-Pb ages of granitoids from the so-called early granodiorites of the northwest Iberian Variscan belt. The U-Pb results attest to significant magmatic activity in Visean time (ca. 347–337 Ma) that generated a hitherto poorly constrained granitoid suite in the northwest Iberian tract of the western European Variscan belt realm. This early Carboniferous suite (ECS) is mainly composed of peraluminous cold and hot crustal granodiorites and monzogranites with minor associated mafic rocks that attest to minor involvement of mantle melting. Based on the geochronological and geochemical data, we compare the Visean granitoids with younger Variscan granitoids in northwest Iberia and, in view of the tectonothermal scenarios of the Variscan collision in northwest Iberia, propose a model for the genesis of the ECS in northwest Iberia that involves rapid melting upon fast exhumation of the thickened Gondwanan crust in the course of the protracted Variscan collision.This work has been funded by the Spanish Ministry of Economy and Competitiveness under the project ODRE III—Oroclines & Delamination: Relations & Effects (CGL2013-46061-P) and Происхождение, металлогения, климатические эффекты и цикличность Крупных Изверженных Провинций (КИП) (Origin, metallogeny, climatic effects, and cyclical large igneous provinces) (14.Y26.31.0012; Russian Federation) to Gutiérrez-Alonso and López-Carmona and CGL-2016-76438-P to Fernández-Suárez. López-Carmona was also funded by a “Juan de la Cierva” grant (reference FJCI-2014-20740).Peer reviewe

Differential Behavior Between Isolated and Aggregated Rabbit Auricular Chondrocytes on Plastic Surfaces

A knowledge of the behavior of chondrocytes in culture is relevant for tissue engineering. Chondrocytes dedifferentiate to a fibroblast-like phenotype on plastic surfaces. Dedifferentiation is reversible if these cells are then cultured in suspension. In this report a description is given of how when chondrocyte aggregates formed in suspension are next seeded on plastic, most of them attach as round or polygonal cells. This morphological differentiation, with synthesis of type II collagen, is stable for long culture periods. This simple method can be of use as a model for studies of chondrocyte behavior on plastic. The results indicate that in addition to culture conditions, such as cell isolation method or cell density, chondrocyte behavior on plastic depends on the presence of aggregates

Effects of Extracellular Matrix on the Morphology and Behaviour of Rabbit Auricular Chondrocytes in Culture

Isolated chondrocytes dedifferentiate to a fibroblast-like shape on plastic substrata and proliferate extensively, but rarely form nodules. However, when dissociation is not complete and some cartilage remnants are included in the culture, proliferation decreases and cells grow in a reticular pattern with numerous nodules, which occasionally form small cartilage-like fragments. In an attempt to reproduce this stable chondrogenic state, we added a cartilage protein extract, a sugar extract, and hyaluronan to the medium of previously dedifferentiated chondrocytes. When protein extract was added, many cartilaginous nodules appeared. Hyaluronan produced changes in cell phenotype and behaviour, but not nodule formation. Protein extract has positive effects on the differentiation of previously proliferated chondrocytes and permits nodule formation and the extensive production of type-II collagen. A comparison with incompletely dissociated chondrocyte cultures suggests that the presence of some living cells anchored to their natural extracellular matrix provides some important additional factors for the phenotypical stability of chondrocytes on plastic surfaces. In order to elucidate if it is possible that the incidence of apoptosis is related to the results, we also characterized the molecular traits of apoptosis

Tumor en hueco poplíteo en 1 niño: diagnóstico diferencial a propósito de 1 caso

Se presenta 1 caso de tumoración en hueco poplíteo en 1 paciente de 15 años de edad. En la exploración clínica inicial encontramos una tumoración de consistencia dura sin signos inflamatorios. Los estudios con RNM y gammagrafía ósea nos orientaban hacia una patología benigna. El estudio anatomopatológico realizado tras la exéresis de la tumoración lo caracterizó como zona de necrosis isquémica con calcificación distrófica de la inserción muscular del tendón del músculo semitendinoso.A 15-year-old boy with a poplited tumor in the knee is presented. The initial exploration showed a firm mass without inflammatory signs. RNM and bone scintigraphy disclosed benign pathology. The pathological diagnosis showed a central area of isquemic necrosis, with distrofic calcification of the semitendinous muscle

Cepas del género Penicillium aisladas en Cataluña

En el presente trabajo intentamos la clasificación de 133 cepas pertenecientes a 37 especies del género Penicillium Link, aisladas en Cataluña, así como la descripción macro y microscópica de todas ellas para su posible inclusión en un índice de la flora micológica de nuestro país

Recreational water skiing in people with paraplegia: A study of three cases

Objetivos: se analizaron la condición cardiorrespiratoria y la intensidad de esfuerzo durante la práctica recreativa del esquí náutico de slalom. Metodología: participaron tres esquiadores náuticos con paraplejia moderadamente activos. Realizaron un test incremental en un ergómetro de brazos para determinar su VO2pico y los umbrales ventilatorios y completaron 3 sesiones de práctica de esquí náutico, separadas por 48h, registrándose la FC cada 5 s. Resultados: obtuvieron un VO2pico de 22,3 ± 0,6 mL·kg-1·min-1 y los umbrales ventilatorios se analizaron al ~80 y ~50% del VO2pico. La FC media en las sesiones de esquí náutico fue de 111 ppm, lo que representó una intensidad de ~45% de la FC de reserva (FCR), permaneciendo por encima del 40% de la FCR ~12 min. Conclusión: la intensidad moderada de la práctica recreativa de esquí náutico de slalom podría servir para mantener o mejorar la condición cardiorrespiratoria en estas tres personas con paraplejiaObjectives: the cardiorespiratory fitness and the intensity of effort were analyzed during the recreational practice of slalom water skiing. Methodology: three moderately active water skiers with paraplegia participated. They performed an incremental test on an arm ergometer to determine their VO2peak and ventilatory thresholds and completed 3 sessions of water skiing, separated by 48h, where the HR was recorded every 5 s. Results: they obtained a VO2peak of 22.3 ± 0.6 mL·kg-1·min-1 and the ventilatory thresholds were analyzed at ~80 and ~50% of the VO2peak. The average heart rate in the water ski sessions was 111 bpm, which represented an intensity of ~45% of the heart rate reserve (HRR), remaining above 40% of the HRR ~12 min. Conclusion: the moderate intensity of recreational slalom skiing could serve to maintain or improve the cardiorespiratory fitness in these three people with paraplegi

Episodic melting and magmatic recycling along 50 Ma in the Variscan belt linked to the orogenic evolution in NW Iberia

The advent of a large amount of more precise U-Pb age data on Variscan granitoids from NW Iberia in recent years has provided a more focused picture of the magmatic history of the Western European Variscan belt (WEVB). Based on these data, three main pulses of magmatic activity seem to be well established

Phase Transition in Liquid Drop Fragmentation

A liquid droplet is fragmented by a sudden pressurized-gas blow, and the resulting droplets, adhered to the window of a flatbed scanner, are counted and sized by computerized means. The use of a scanner plus image recognition software enables us to automatically count and size up to tens of thousands of tiny droplets with a smallest detectable volume of approximately 0.02 nl. Upon varying the gas pressure, a critical value is found where the size-distribution becomes a pure power-law, a fact that is indicative of a phase transition. Away from this transition, the resulting size distributions are well described by Fisher's model at coexistence. It is found that the sign of the surface correction term changes sign, and the apparent power-law exponent tau has a steep minimum, at criticality, as previously reported in Nuclear Multifragmentation studies [1,2]. We argue that the observed transition is not percolative, and introduce the concept of dominance in order to characterize it. The dominance probability is found to go to zero sharply at the transition. Simple arguments suggest that the correlation length exponent is nu=1/2. The sizes of the largest and average fragments, on the other hand, do not go to zero but behave in a way that appears to be consistent with recent predictions of Ashurst and Holian [3,4].Comment: 10 pages, 11 figures. LaTeX (revtex4) with psfig/epsfi