83 research outputs found
Discusión sobre el matamorfismo regional del Guadarrama oriental (Sistema Central español)
Se aportan datos que confirman que el metamorfismo del Guadarrama oriental corresponde al tipo distena-sillimanita, con un desarrollo zona1 que tiene grandes analogías con el trictaniorfismo barrowiense. Las zonas encontradas: cloritacloritoide-estaurolita-distena-sillimani, y el desarrollo generalizado del almandino en la mayor parte del ámbito metatii0rfico indican unas condiciones de presión elevada y de un gradiente geotérmico relativamente reducido. Este tipo de sucesión metamórfica es considerablemente diferente del que existe en otros sectores del del Guadarrama central y occidental, donde aparecen tipos de más baja presión y (o) más alta temperatura con andalucita o cordierita como minerales sintomáticos en grados elevados de este metamorfismo. Para este sector no son aceptables muchos de los datos y las conclusiones publicadas por BARD et al. (1970, 1971)
Mineralogía y evolución de las pegmatitas graníticas de La Cabrera (Sistema Central Español)
En relación con el plutonismo granítico de La Cabrera se pueden distinguir varias clases de pegmatitas, atendiendo al tipo de granito que las origina, forma de emplazamiento y relación con el encajante. Estas pegmatitas están constituidas fundamentalmente por cuarzo, albita, feldespato potásico y micas, pudiendo ir acompañadas de cordierita, granate y turmalina. Ocasionalmente se ha constatado la presencia de apatito, rutilo, casiteria, gadolinita, thalenita y bavenita. Son características generales de estas pegmatitas la pobreza en ferromagnesianos, ausencia casi absoluta de minerales fosfatados, así como una gran escasez de moscovita que cuando aparece tiene un carácter tardío en relación con los principales minerales pegmatíticos s.s. Algunos cuerpos pegmatíticos presentan unos procesos evolutivos complejos que denotan una cierta actividad hidrotermal, continuada hasta una etapa de muy baja temperatura. Esta evolución cabe referirla a dos etapas principales: a) Etapa de formación de clinozoisita, prehnita, axinita. b) Etapa de formación de ceolitas. En relación con la primera de estas etapas y de una manera ocasional, pueden formarse algunos sulfuros, así como wolframita, schelita y fluorita. Aceptándose una presión menor de 2 kb durante la formación de estas pegmatitas, se discuten una serie de posibles reacciones para la formación de los nuevos minerales anteriormente citados, así como su posible intervalo termodinámico de cristalización
Metal-insulator transition in NdEuNiO compounds
Polycrystalline NdEuNiO () compounds
were synthesized in order to investigate the character of the metal-insulator
(MI) phase transition in this series. Samples were prepared through the sol-gel
route and subjected to heat treatments at 1000 C under oxygen
pressures as high as 80 bar. X-ray Diffraction (XRD) and Neutron Powder
Diffraction (NPD), electrical resistivity , and Magnetization
measurements were performed on these compounds. The results of NPD and XRD
indicated that the samples crystallize in an orthorhombic distorted perovskite
structure, space group . The analysis of the structural parameters
revealed a sudden and small expansion of 0.2% of the unit cell volume
when electronic localization occurs. This expansion was attributed to a small
increase of 0.003 \AA{} of the average Ni-O distance and a simultaneous
decrease of of the Ni-O-Ni superexchange angle. The
measurements revealed a MI transition occurring at temperatures
ranging from to 336 K for samples with and 0.50,
respectively. These measurements also show a large thermal hysteresis in
NdNiO during heating and cooling processes suggesting a first-order
character of the phase transition at . The width of this thermal
hysteresis was found to decrease appreciably for the sample
NdEuNiO. The results indicate that cation disorder
associated with increasing substitution of Nd by Eu is responsible for changing
the first order character of the transition in NdNiO.Comment: 19 pages, 9 figure
Vitamin D nutritional status and vitamin D regulated antimicrobial peptides in serum and pleural fluid of patients with infectious and noninfectious pleural effusions
Background: Vitamin D and vitamin D dependent antimicrobial peptides such as Cathelicidin (LL-37) and ?-defensin 2 have an important role in innate and adaptative immunity, but their role in pleural effusions has not been studied before. Methods: Serum and pleural fluid samples from 152 patients with pleural effusion were collected, corresponding to 45 transudates and 107 exudates, 51 infectious effusions (14 complicated and 37 non-complicated), 44 congestive heart failure effusions and 38 malignant effusions. The levels of 25 OH-vitamin D, 1,25-(OH)2-vitamin D, Vitamin D Binding Protein (VDBP), LL-37 and ?-defensin 2, both in serum and pleural fluid were evaluated in this prospective study. Differences between groups were analysed using unpaired t tests or Mann?Whitney tests. Correlations between data sets were examined using Pearson correlation coefficient or Spearman rank correlation coefficient. Diagnostic accuracy was estimated using ROC curve analysis. Results: Low serum 25 OH vitamin D levels were found in all groups. Infectious effusions (IE) had higher serum and pleural fluid LL-37 levels compared to congestive heart failure or malignant effusions. Among IE, complicated had higher serum and pleural fluid LL-37 levels, and lower serum ?-defensin-2 levels. Positive correlations were found between serum 25 OH-vitamin D levels and serum or pleural 1,25-(OH)2-vitamin D levels, and between 1,25-(OH) 2-vitamin D and LL-37 serum. Diagnostic accuracy of the different molecules was moderate at best. Conclusions: Hypovitaminosis D is highly prevalent in pleural effusions. LL-37 is produced intrapleurally in IE. This production is higher in complicated IE. No evidence of pleural production of ?-defensin 2 was found in any of the groups. Diagnostic accuracy of the different molecules is at the best moderate for discriminating different types of effusions
Diagnostic, etiologic, and genetic aspects of congenital ichthyoses at birth: Characteristics of the ECEMC cases
Dismorfología, Citogenética y Clínica: Resultados de estudios sobre los datos del ECEMCThe Ichthyoses constitutes a large family of genetic skin diseases characterized by dry skin and variable degrees of blisters and scales. There are at least twenty varieties of ichthyosis, with a wide range of severity and associated symptoms, and genetic heterogeneity (autosomal dominant, autosomal recessive, and X-linked inheritance). The clinical symptoms, which are non-specific, may not be apparent. We have attempted to provide a classification of the ichthyoses and some guidance for the diagnosis and management of these conditions. The present classification is based in the type of alteration of the skin layer, the molecular findings, the biochemical characteristics, and the family history.There are three main categories, which include different subgroups of ichthyoses: 1) Those that are caused by an altered process of keratinocytic diferenciation (altered intermediate filaments/keratins). This category includes the following subgroups: a) Harlequin fetus; b) bullous erythroderma ichthyosiformis congenital; c) Ichthyosis bullosa of Siemens; d) Ichthyosis hystrix of Curth-Macklin; and e) Ichthyosis vulgaris. 2) Those that are caused by a deficient formation of the cornified envelope (transglutaminase 1 enzyme deficiency). In this category we include two main subgrups: a) Lamellar ichthyosis AR, which includes i) ichthyosis lamellar (IL1, IL2, IL3, IL4, and IL5), and ii) ichthyosiform erythroderma congenital nonbullous, and b) Nonlamellar ichthyosis and nonerythrodermic congenital ichthyosis AR. 3) Those caused by an abnormal steroid sulfatase (X-linked Ichtyosis). In spite of having only data at birth and the lack of molecular analysis, we attempted to classify the ECEMC cases according to this classification using available clinical data. We also calculated the frequency of this disease identified at birth, and provide some guidance for the clinical diagnosis, the management of the affected newborn, and the information that should be offered to the parents.N
Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)
This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and
Technology (CICYT), the
Spanish National Parks agency, the European Commission, the
Spanish Ministry of Science, and the European
Social Fund
Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)
This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and
Technology (CICYT), the
Spanish National Parks agency, the European Commission, the
Spanish Ministry of Science, and the European
Social Fund
Cellulose Biosynthesis Inhibitors: Comparative Effect on Bean Cell Cultures
The variety of bioassays developed to evaluate different inhibition responses for cellulose biosynthesis inhibitors makes it difficult to compare the results obtained. This work aims (i) to test a single inhibitory assay for comparing active concentrations of a set of putative cellulose biosynthesis inhibitors and (ii) to characterize their effect on cell wall polysaccharides biosynthesis following a short-term exposure. For the first aim, dose-response curves for inhibition of dry-weight increase following a 30 days exposure of bean callus-cultured cells to these inhibitors were obtained. The compound concentration capable of inhibiting dry weight increase by 50% compared to control (I50) ranged from subnanomolar (CGA 325′615) to nanomolar (AE F150944, flupoxam, triazofenamide and oxaziclomefone) and micromolar (dichlobenil, quinclorac and compound 1) concentrations. In order to gain a better understanding of the effect of the putative inhibitors on cell wall polysaccharides biosynthesis, the [14C]glucose incorporation into cell wall fractions was determined after a 20 h exposure of cell suspensions to each inhibitor at their I50 value. All the inhibitors tested decreased glucose incorporation into cellulose with the exception of quinclorac, which increased it. In some herbicide treatments, reduction in the incorporation into cellulose was accompanied by an increase in the incorporation into other fractions. In order to appreciate the effect of the inhibitors on cell wall partitioning, a cluster and Principal Component Analysis (PCA) based on the relative contribution of [14C]glucose incorporation into the different cell wall fractions were performed, and three groups of compounds were identified. The first group included quinclorac, which increased glucose incorporation into cellulose; the second group consisted of compound 1, CGA 325′615, oxaziclomefone and AE F150944, which decreased the relative glucose incorporation into cellulose but increased it into tightly-bound cellulose fractions; and the third group, comprising flupoxam, triazofenamide and dichlobenil, decreased the relative glucose incorporation into cellulose and increased it into a pectin rich fraction
Very low frequency Syndromes
Dismorfología, Citogenética y Clínica: Resultados de estudios sobre los datos del ECEMCThe aim of this chapter is to summarize updated knowledge about the clinical characteristics, etiology, genetic and molecular aspects, as well as mechanisms involved in syndromes having very low frequency, in order to promote their better recognition. During the last five years, a total of 30 syndromes have been published in this chapter of the Boletín del ECEMC. This issue includes the following selected syndromes: Crouzon, Pfeiffer, Apert, Saethre-Chotzen, Carpenter and Muenke. All share craniosynostosis as the main clinical feature but also present with other birth defects, the most important being limb malformations, specially syndactyly and polydactyly. Over 100 syndromes with craniosynostosis have been described, usually involving multiple sutures, and several of them are associated with limb malformations. The clinical overlapping between those syndromes makes difficult to perform a neonatal diagnosis, based on their clinical findings. However, molecular genetic testing, specifically of the FRGR1-3 and TWIST1 genes, could help to establish the diagnosis of some of them. Early diagnosis is important for establishing the most suitable treatment for each patient, as well as to offer an accurate genetic counselling and the possibility of preimplantational and/or prenatal diagnosis.N
Survival and long-term maintenance of tertiary trees in the Iberian Peninsula during the Pleistocene. First record of Aesculus L.
The Italian and Balkan peninsulas have been places traditionally highlighted as Pleistocene glacial refuges. The Iberian Peninsula, however, has been a focus of controversy between geobotanists and palaeobotanists as a result of its exclusion from this category on different occasions. In the current paper, we synthesise geological, molecular, palaeobotanical and geobotanical data that show the importance of the Iberian Peninsula in the Western Mediterranean as a refugium area. The presence of Aesculus aff. hippocastanum L. at the Iberian site at Cal Guardiola (Tarrasa, Barcelona, NE Spain) in the Lower– Middle Pleistocene transition helps to consolidate the remarkable role of the Iberian Peninsula in the survival of tertiary species during the Pleistocene. The palaeodistribution of the genus in Europe highlights a model of area abandonment for a widely-distributed species in the Miocene and Pliocene, leading to a diminished and fragmentary presence in the Pleistocene and Holocene on the southern Mediterranean peninsulas. Aesculus fossils are not uncommon within the series of Tertiary taxa. Many appear in the Pliocene and suffer a radical impoverishment in the Lower–Middle Pleistocene transition. Nonetheless some of these tertiary taxa persisted throughout the Pleistocene and Holocene up to the present in the Iberian Peninsula. Locating these refuge areas on the Peninsula is not an easy task, although areas characterised by a sustained level of humidity must have played an predominant role
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