408 research outputs found
New palynological and isotopic data for the Triassic of the western Cantabrian Mountains (Spain)
Triassic carbonate rocks of the western Cantabrian Mountains, northern Spain, have long been attributed to the Muschelkalk facies, and as such have been correlated with other Middle Triassic carbonate units of the Iberian Peninsula. Data on palynological assemblages here presented, point to a Ladinian-lower Carnian age of the upper part of the Buntsandstein facies in this area. In addition, the 87Sr/86Sr ratio of the limestones formerly attributed to the Muschelkalk facies indicates a Norian or Norian-Rhaetian boundary age. These findings also imply that the position of the marine coast during the Middle Triassic Tethys transgression should be moved to a more easterly position, in the Basque Country.Las rocas carbonatadas triásicas que afloran en la zona occidental de la Cordillera Cantábrica en el norte de España, han sido tradicionalmente atribuidas al Muschelkalk por correlación con las unidades carbonatadas del Triásico Medio de otras áreas de la PenÃnsula Ibérica. Las asociaciones palinológicas encontradas en la parte superior de las facies Buntsandstein que afloran en esta área, indican una edad Ladiniense-Carniense inferior. La relación 87Sr/86Sr de los niveles de calizas atribuidos anteriormente al Muschelkalk, son propios de los carbonatos de edad Noriense o Noriense-Rhetiense. Estos datos implican, además, que la posición de la lÃnea de máximo avance del mar del Tethys hacia occidente durante el Triásico Medio se situó en una posición más oriental y dentro del PaÃs Vasco
Nuevos datos palinológicos e isotópicos del Triásico de la Cordillera Cantábrica occidental (España)
Triassic carbonate rocks of the western Cantabrian Mountains, northern Spain, have long been attributed to the Muschelkalk faciès, and as such have been correlated with other Middle Triassic carbonate units of the Iberian Peninsula. Data on palynological assemblages here presented, point to a Ladinian-lower Carnian age of the upper part of the Buntsandstein faciès in this area. In addition, the 87Sr/86Sr ratio of the limestones formerly attributed to the Muschelkalk faciès indicates a Norian or Norian-Rhaetian boundary age. These findings also imply that the position of the marine coast during the Middle Triassic Tethys transgression should be moved to a more easterly position, in the Basque Country.Las rocas carbonatadas triásicas que afloran en la zona occidental de la Cordillera Cantábrica en el norte de España, han sido tradicionalmente atribuidas al Muschelkalk por correlación con las unidades carbonatadas del Triásico Medio de otras áreas de la PenÃnsula Ibérica. Las asociaciones palinológicas encontradas en la parte superior de las facies Buntsandstein que afloran en esta área, indican una edad Ladiniense-Carniense inferior. La relación 87Sr/86Sr de los niveles de calizas atribuidos anteriormente al Muschelkalk, son propios de los carbonatos de edad Noriense o Noriense-Rhetiense. Estos datos implican, además, que la posición de la lÃnea de máximo avance del mar del Tethys hacia occidente durante el Triásico Medio se situó en una posición más oriental y dentro del PaÃs Vasco.Depto. de Geodinámica, EstratigrafÃa y PaleontologÃaFac. de Ciencias GeológicasTRUEMinisterio de Educación y Cienciapu
PalinologÃa del Cretácico Inferior de la sección de Montoria-La Mina (Cuenca Vasco-Cantábrica, España): polen de angiospermas primitivas
La sección del Cretácico Inferior de Montoria-La Mina se encuentra en el margen sur de la Cuenca Vasco-Cantábrica (España). Sus materiales están integrados por una sucesión de lutitas y arcillas con niveles de lignitos y areniscas que se depositaron en un cinturón deltáico, pudiéndose atribuir a la Formación Escucha. Se han obtenido asociaciones palinológicas bien conservadas con un número
significativo de palinomorfos que ha permitido realizar estudios de tipo cuantitativo en ocho de los doce niveles analizados. Se ha puesto de manifiesto la existencia de una flora diversa, integrada por cuarenta y cuatro tipos diferentes de criptógamas vasculares y veintiocho de fanerógamas de las divisiones Bryophyta, Lycophyta, Pteridophyta, Pteridospermophyta, Coniferophyta,
Cycadophyta/Ginkgophyta, Gnetophyta y Magnoliophyta. Las asociaciones palinológicas se encuentran dominadas por granos de polen anemófilo de Corollina obidosensis e Inaperturopollenites dubius y por esporas psiladas de Cyathidites australis, que indican la existencia de climas cálidos y secos. Es relevante el registro de polen de angiospermas primitivas en las asociaciones estudiadas, correspondiendo a formas de tamaño pequeño, reticuladas y, por lo general, columeladas. Se describen formas inaperturadas, operculadas, monosulcadas y tricotomosulcadas que se han atribuido a los grupos Pre-Afropollis, Clavatipollenites, Liliacidites, Retimonocolpites y Retimonoporites. La aparición de estos grupos polÃnicos permite relacionar las asociaciones registradas con las de la parte inferior de la Zona I del Grupo Potomac (Maryland, USA) y con las del Cretácico Inferior de Israel.
[ABSTRACT]
The Lower Cretaceous Montoria-La Mina section is located in the extreme southern part of the Basque–Cantabrian Basin (Spain). The succession might be included into the Escucha Formation and contains siltstones and clays with interbedded deltaic lignite and sandstone rocks. The palynological analysis of these rocks shows well preserved miospore assemblages with significant numbers of specimens in eight of the twelve analysed horizons. A diverse flora composed of forty four vascular cryptogams and twenty eight fanerogams are identified, included in the divisions Bryophyta, Lycophyta, Pteridophyta, Pteridospermophyta, Coniferophyta, Cycadophyta/Ginkgophyta, Gnetophyta
and Magnoliophyta. The palynological assemblages are dominated by anemophilous pollen grains of Corollina obidosensis and Inaperturopollenites dubius, as well as psilate spores of Cyathidites australis, which suggest warm and dry climatic conditions. The occurrence of pollen grains of ancient angiosperms is significant in the studied assemblages. They were identified as small-sized, reticulate and generally collumelate miospores. Inaperturate, operculate, monosulcate and trichotomosulcate forms attributed to the Pre-Afropollis, Clavatipollenites,
Liliacidites, Retimonocolpites and Retimonoporites pollen groups are described. The appearance of these palynological groups are compared to those in the lower part of Zone I of Potomac Group (Maryland, USA) and in the Lower Cretaceous of Israel
Multiresidue determination of quinolones regulated by the European Union in bovine and porcine plasma. Application of chromatographic and capillary electrophoretic methodologies
This paper presents the multiresidue determination of the series of quinolones regulated by the European Union (marbofloxacin, ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid and flumequine) in bovine and porcine plasma using capillary electrophoresis and liquid chromatography with ultraviolet detection (CE-UV, LC-UV), liquid chromatography-mass spectrometry and -tandem mass spectrometry (LC-MS, LC-MS/MS) methods. These procedures involve a sample preparation by solid-phase extraction for clean-up and preconcentration of the analytes before their injection into the separation system. All methods give satisfactory results in terms of linearity, precision, accuracy and limits of quantification. The suitability of the methods to determine quinolones was evaluated by determining the concentration of enrofloxacin and ciprofloxacin in real samples from pig plasma and cow plasm
Neutron Beam Effects on Spin Exchange Polarized He-3
We have observed depolarization effects when high intensity cold neutron
beams are incident on alkali-metal-spin-exchange polarized He-3 cells used as
neutron spin filters. This was first observed as a reduction of the maximum
attainable He-3 polarization and was attributed to a decrease of alkali-metal
polarization, which led us to directly measure alkali-metal polarization and
spin relaxation over a range of neutron fluxes at LANSCE and ILL. The data
reveal a new alkali-metal spin-relaxation mechanism that approximately scales
as the square root of the neutron capture-flux density incident on the cell.
This is consistent with an effect proportional to the recombination-limited ion
concentration, but is much larger than expected from earlier work.Comment: submitted to Physical Review Letter
Necrotic loxoscelism in lower limb and reconstruction with skin autograft
Loxesceles are small spiders, from 9 to 25 mm, with a dark brown spot on the dorsal part in the shape of an inverted violin. They are common in northwestern Mexico and can live at temperatures of 8 to 40°C. These spiders are considered of medical importance because their venom is dermonecrotic, with proteolytic and necrotic action, which is generated in two apocrine glands. The cutaneous clinical picture is the most frequent, with edema, erythema and ischemia that tends to evolve to ulceration and deep necrosis. The key to treatment is early debridement to avoid complications. We presented the case of a 57-year-old female patient who developed an inflammatory condition secondary to a fiddler spider bite involving the left lower extremity. Her evolution to necrosis and late diagnosis required surgical debridement and use of negative pressure therapy (VAC), followed by harvesting and placement of partial thickness skin autograft, obtaining a successful aesthetic and functional result
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