995 resultados para Bacia do Araripe(NE)


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Las notas que siguen son un avance de los resultados obtenidos en el estudio que estamos llevando a cabo sobre el género Dianthus L. en el NE de la Península Ibérica, y versan sobre algunos de los táxones que consideramos más conflictivos.

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En el sector suroriental de la Cuenca del Ebro, la inclinación paleomagnética obtenida en las sucesiones aluviales oligocenas es considerablemente menor que la esperable, si se considera la paleolatitud de referencia calculada para esa región durante el Oligoceno. Este error de inclinación puede deberse a diversos factores, como el control hidrodinámica de las partículas magnéticas en el medio deposicional, la compactación diferencial del sedimento durante el enterramiento, o bien a la deformación tectónica. Este trabajo se ha centrado en su estudio en dos sucesiones dominantemente aluviales, donde previamente se había establecido su magnetoestratigrafia. Las litofacies aluviales y lacustres estudiadas se han agrupado en cinco grupos: areniscas grises, areniscas rojas y versicolores, limos rojos, lutitas rojas y calizas. Se ha demostrado la existencia de una correlación entre la abundancia de filosilicatos y el error de inclinación. De esta manera, las litofacies con un bajo porcentaje de filosilicatos (calizas y areniscas grises) presentan errores de unos 5', estadisticarnente no significativos, con respecto a la inclinación de referencia. Por el contrario, en materiales con un porcentaje más elevado de filosilicatos (limos y arcillas) el error puede llegar a los 25'. Este hecho no tiene repercusión en la interpretación de las polaridades magnéticas, pero si en las reconstmcciones palinspásticas y paleogeográficas basadas en los cálculos de paleolatitudes a partir de las paleoinclinaciones. Los resultados obtenidos demuestran la necesidad de cautela en la propuesta de conclusiones basadas exclusivamente en este tipo de información.

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Se estudia la composiciÛn y estructura de la comunidad de macroinvertebrados a lo largo de un transecto en profundidad en el lago Redó (Pirineos). Este estudio se enmarca dentro del proyecto de ámbito europeo MOLAR (Mountain Lake Research). Un equipo de buceadores muestreo dos tipos de substrato, piedras y fondos blandos, cada 2 m desde los 2 a los 20 m de profundidad. En la parte m·s profunda del lago las muestras se tomaron con draga Ekman (tres rÈplicas). Todas las muestras se tomaron el mismo día, el 15 de Julio de 1997. Los resultados, mediante un análisis de autocorrelación de Mantel, muestran que no existe un gradiente continuo en la sustituciÛn de unas especies por otras en la comunidad sobre substrato rocoso, sino que se distinguen dos discontinuidades claras, una a los 4 metros y otra a los 14 metros. La primera separa las especies propias de la zona litoral respecto a las de la zona sublitoral, mientras que la segunda coincide con la parte inferior de la termoclina, una zona siempre mas frÌa, con menos luz y con mayor acumulación de material fino sobre los sustratos duros a la vez que desaparece la cobertura algal que cubrÌa las piedras hasta esta profundidad. Respecto al sustrato existen especies que claramente prefieren el sustrato blando (oligoquetos, o los quironÛmidos Micropsectra radialis y Pseudodiamesa nivosa), mientras que otras eran más abundantes o exclusivas de los sustratos duros (Radix peregra, Plectrocnemia laetabilis, Psectrocladius octomaculatus). Estos resultados seran muy útiles para la interpretaciÛn de los datos paleolimnolÛgicos de los cores que actualmente se est·n estudiando en el lago.

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El complejo de abanico costero de Sant Lloren$ del Munt se encuentra en el margen sureste de la cuenca del Ebro, en el noroeste de España. Durante el Paleógeno, este margen de la cuenca estuvo sometido a unas condiciones de tipo transpresivo durante las que se desarrollaron una serie de pliegues, cabalgarnientos y failas de desgarre. Esta estructuración dió lugar a un bloque tectónicamente elevado constituido por materiales del zócalo paleozoico y la cobertera mesozoica que alimentaba una serie de abanicos aluviales y costeros, como el de Sant Lloren$ del Munt, que se desarrollaron en el borde de la cuenca del Ebro. El complejo de Sant Lloren$ del Munt presenta depósitos tanto subaereos como submarinos bien desarrollados, donde se han podido diferenciar cinco principales asociaciones de facies : abanico aluvial proximal, abanico aluvial distal/llanura de abanico costero, frente deltaico, talud deltaico/offshore y plataforma carbonática. Se han tomado 32 muestras de las facies marinas del Bartoniense para el estudio de su contenido palinológico y en 19 de éstas se han encontrado granos de polen triásicos. La mayor parte de las muestras con porcentajes altos de palinomorfos triásicos se corresponden con facies detríticas ligadas a períodos con importantes aportes sedimentarios. Se ha determinado la presencia de más de 15 palinomorfos triásicos diferentes, la mayoría de los cuales nunca han sido encontrados en las muestras tomadas en los materiales triásicos que afloran en areas relativamente cercanas a la aquí estudiada. Se han encontrado palinomorfos típicos del Kamiense y Nonense (Tnásico superior). Los materiales del Triásico superior debieron aflorar extensamente durante el Bartoniense en el actual Valles occidental. El área fuente del complejo de Sant Lloren$ del Munt estuvo constituida tanto por materiales del zócalo paleozoico como de la cobertera Triásica, alcanzando esta última un desarrollo mucho más importante de lo que se había deducido hasta el momento. Existe una relación entre los tramos de las secuencias (fundamentales y compuestas), el contenido en palinomorfos triásicos resedimentados y el grado de conservación del polen. Existe también una relación entre el tipo de facies y el contenido en palinomorfos triásicos resedimentados.

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The magnetostratigraphic analysis of the middle to late Miocene continental deposits from the Valles-Penedes basin, combined with its well-documented fossil mammal record, provides a well-resoluted chronology for the upper basin infill. It is based on the biostratigraphic and magnetostratigraphic cross-correlation of 18 sections throughout the alluvial and transitional/shallow marine sequences in the Western Valles area. The biostratigraphic framework consists of 24 mammal localities of upper Aragonian and Vallesian age. Correlation of the studied sections to the geomagnetic polarity time scale (GPTS) is based on the distinctive pattern of local magnetozones, as well as the radiometric age of the late Vallesian fauna from the Bicorp Basin (9.6 + 0.3 Ma) and the known relationship of the late Vallesian assemblages with marine beds belonging to the planktonic forarninifera N16 zone. It has led to an absolute dating of the fauna1 events and a precise chronostratigraphy of the Vallesian marnrnal stage in its type area. The Hipparion First Appearance Datum (FAD) defines the lower Vallesian boundary and is dated at 11.1 Ma, at the base of chron C5r. ln. It is in good agreement with radiometric ages from the early Hipparion bearing sites in the Vienna Basin (1 1.1 * 0.5 Ma) and the classic Howenegg locality in Germany (10.8 * 0.3 Ma). It also agrees with the age of the turkish localities of Yailacilar (1 1.6 + 0.25 Ma) and Yenieskihisar-2 (1 1.1 * 0.2 Ma) with absence of Hipparion. Al1 these support the isochrony of the dispersa1 of Hipparion throughout the Mediterranean region. A possible isochrony at a larger geographical scale (Old World, Mesogea) must await more reliable ages of the Hipparion FAD in Asia and Africa. The Cricetulodon FAD that defines the MN9a/MN9b boundary occurs at the middle part of C5n. Assuming an on average constant sedimentation rate, this datum has an age of approximately 10.4 Ma. The earlyllate Vallesian boundary is marked by one of the most distinct fauna1 events of the late Neogene: the dispersa1 of the muridae Progonomys into Europe and North Africa, which coincides with an important macromarnmal turnover. The first extensive appearance of Progonomys in Europe (MN9íMN10 boundary) is dated at 9.7 Ma (C4Ar3r), showing a remarkable diachrony with the Himalayan region. F9i d lly, the FAD of Rotundomys bressnnus occurs in the upper part of C4Ar.ln (9.2-9.3 Ma). The Vallesian spans 2.4 Myr, from 11.1 Ma (CSr.ln) to 8.7 Ma (C4An), and correlates to the early Tortonian.

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Triangular facets, related drainage basins, alluvial fans and subtle scarps reveal the recent activity of the normal Amer fault (NE Spain). The 1427 earthquakes which reached epicentral intensities ranging between VI1 and VI11 have been attributed to the Amer fault. However, the geomorphologic and geologic characteristics of this fault (30 km length) suggest that it might be capable of producing larger earthquakes than those occurred during de 15th century.

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This paper presents sorne examples of didactic resources created to contribute to the spreading of hydrothermalism in the Province of Girona

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The abandonment of agricultural land in mountainous areas has been an outstanding problem along the last century and has captured the attention of scientists, technicians and administrations, for the dramatic consequences sometimes occurred due to soil instability, steep slopes, rainfall regimes and wildfires. Hidromorfological and pedological alterations causing exceptional floods and accelerated erosion processes has therefore been studied, identifying the cause in the loss of landscape heterogeneity. Through the disappearance of agricultural works and drainage maintenance, slope stability has resulted severely affected. The mechanization of agriculture has caused the displacement of vines, olives and corks trees cultivation in terraced areas along the Mediterranean catchment towards more economically suitable areas. On the one hand, land use and management changes have implicated sociological changes as well, transforming areas inhabited by agricultural communities into deserted areas where the colonization of disorganized spontaneous vegetation has buried a valuable rural patrimony. On the other hand, lacking of planning and management of the abandoned areas has produced badlands and infertile soils due to wildfire and high erosion rates strongly degrading the whole ecosystems. In other cases, after land abandonment a process of soil regeneration has been recorded. Investigations have been conducted in a part of NE Spain where extended areas of terraced soils previously cultivated have been abandoned in the last century. The selected environments were semi-abandoned vineyards, semi-abandoned olive groves, abandoned stands of cork trees, abandoned stands of pine trees, scrubland of Cistaceaea, scrubland of Ericaceaea, and pasture. The research work was focused on the study of most relevant physical, chemical and biological soil properties, as well as runoff and erosion under soils with different plant cover to establish the abandonment effect on soil quality, due to the peculiarity and vulnerability of these soils with a much reduced depth. The period of observation was carried out from autumn 2009 to autumn 2010. The sediment concentration of soil erosion under vines was recorded as 34.52 g/l while under pasture it was 4.66 g/l. In addition, the soil under vines showed the least amount of organic matter, which was 12 times lower than all other soil environments. The carbon dioxide (CO2) and total glomalin (TG) ratio to soil organic carbon (SOC) in this soil was 0.11 and 0.31 respectively. However, the soil under pasture contained a higher amount of organic matter and showed that the CO2 and TG ratio to SOC was 0.02 and 0.11 respectively indicating that the soil under pasture better preserves the soil carbon pool. A similar trend was found in the intermediate soils in the sequence of land use change and abandonment. Soil structural stability increased in the two soil fractions investigated (0.25-2.00 mm, 2.0-5.6 mm) especially in those soils that did not undergo periodical perturbations like wildfires. Soil quality indexes were obtained by using relevant physical and chemical soil parameters. Factor analysis carried out to study the relationship between all soil parameters allowed to related variables and environments and identify those areas that better contribute to soil quality towards others that may need more attention to avoid further degradation processes

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OBJETIVO: No grupo pediátrico, o diagnóstico radiológico dos tumores dos ossos ilíacos, ísquios e púbis apresenta dificuldades e peculiaridades próprias, mas a literatura revisada não trata especificamente desse tema. Este trabalho pretende investigar a existência de padrões radiológicos confiáveis para o diagnóstico diferencial desses tumores. MATERIAIS E MÉTODOS: Foram revistos os achados radiológicos de tumores dos ossos do quadril em dez pacientes com idades entre 8 e 19 anos. RESULTADOS: Reação óssea (esclerose ou lise), reação periosteal (lamelar em camada única, múltiplas camadas ou radial), extensão do tumor no osso e grau de invasão das partes moles revelaram baixa especificidade. As calcificações nas partes moles, consideradas em conjunto, foram inespecíficas. Contudo, separando as próximas do osso comprometido, que apresentam formas e tamanhos variados - padrão I -, daquelas afastadas do osso, finas e amorfas - padrão II -, observamos que o padrão I foi totalmente inespecífico e o padrão II foi identificado nos três casos de osteossarcoma (100%) e em apenas um dos casos de Ewing (16,6%). CONCLUSÃO: Neste material, as calcificações padrão II revelaram sensibilidade de 100% e especificidade de 90% para osteossarcoma. Contudo, sua importância pode não se limitar ao diagnóstico radiológico. As calcificações padrão II indicam, provavelmente, os sítios ideais para biópsia.

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Soitinnus: piano, 4-kät.

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The presence of Dactyloidites ottoi is first recorded in the Eocene Sant Llorenç del Munt fan-delta complex. This constitutes the first citation for the Paleogene. The ichnospecies occurs in the lower part of a prograding fan-delta front sequence, associated to other traces produced by sediment-feeders. This association is substituted in the upper part of the sequence by abundant vertical Ophiomorpha indicating an increase of energetic conditions. The paleoenvironmental setting interpreted for Dactyloidites is consistent with that of previous described occurrences.

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The northwestern margin of the Valencia trough is an area of low strain characterized by slow normal faults and low to moderate seismicity. Since the mid 1990s this area has been the subject of a number of studies on active tectonic which have proposed different approaches to the location of active faults and to the calculation of the parameters that describe their seismic cycle. Fifty-six active faults have been found and a classification has been made in accordance with their characteristics: a) faults with clear evidence of large paleo-, historic or instrumental earthquakes (2/56); b) faults with evidence of accumulated activity during the Plio-Quaternary and with associated instrumental seismicity (7/56); c) faults with evidence of accumulated activity during the Plio-Quaternary and without associated instrumental seismicity (17/56); d) faults with associated instrumental seismicity and without evidence of accumulated activity during the Plio-Quaternary (30/56), and e) faults without evidence of activity or inactive faults. The parameters that describe the seismic cycle of these faults have been evaluated by different methods that use the geological data obtained for each fault except when paleoseismological studies were available. This classification can be applied to other areas with low slip faults because of the simplicity of the approaches adopted. This study reviews the different approaches proposed and describes the active faults located, highlighting the need a) to better understand active faults in slow strain zones through paleoseismological studies, and b) to include them in seismic hazard studies.

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En raison de sa prescription croissante pour des indications d'aide à la réduction des consommations ou au maintien de l'abstinence à l'alcool, le risque d'intoxication volontaire ou accidentelle au baclofène s'accroît et favorise l'admission aux urgences ou en réanimation de comas profonds. La difficulté diagnostique repose sur une relative méconnaissance de cette substance et sur le fait que le baclofène ne fait pas partie des substances mises en évidence par les examens toxicologiques de dépistage habituels. La modification de la pharmaco- cinétique du baclofène en cas de surdosage expose le patient à un coma prolongé, nécessitant dès lors un soutien ventilatoire de longue durée. De manière paradoxale, le baclofène expose également à un risque potentiel de convulsions. En cas de prise en charge adéquate, le pronostic est excellent dans la majorité des cas. En partant d'un cas clinique illustratif et d'une revue de littérature, nous proposons une synthèse des principes de prise en charge d'une intoxication aiguë au baclofène. Baclofen is widely used for the treatment of neurological spastic syndromes and has been recently proposed for the treatment of alcohol dependence. The risk of accidental or self- intoxication with baclofen may therefore increase in the future. Baclofen overdose affects the autonomic nervous system and produces an inhibitory effect on the central nervous system. The classic clinical presentation involves prolonged impaired consciousness or coma and neurovegetative symptoms. Paradoxically, baclofen overdose may also promote the occurrence of seizures. The emergency management is mainly supportive and, in the majority of cases, the prognosis appears excellent. Herein we report a case of baclofen self-intoxication and review the literature regarding the toxicity of baclofen, the clinical presentation of an acute baclofen poisoning and the related principles of management.

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