179 research outputs found
Cartografía geomorfológica y procesos de activos en la cuenca media-alta del río Eria mediante técnicas de SIG.( Provincia de León, España)
El objetivo es la elaboración de la cartografía geomorfológica y de procesos geológicos activos de un tramo del
curso medio de la cuenca del río Eria, en el sector suroccidental de la provincia de León utilizando técnicas de SIG.
El trabajo se ha basado en la fotointerpretación de fotos aéreas en visión estereoscópica, estudio bibliográfico y
aplicación de técnicas de SIG para el análisis de modelos digitales de terreno y mapas derivados (pendientes,
alturas…) y para la representación cartográfica.
Como resultado se distinguen tres dominios de relieve caracterizados por diferentes procesos geológicos: dominio
de los relieves sobre sustrato paleozoico, dominio de los relieves de origen fluvial y dominio de las formas de origen
antrópico. En el primero tienen gran relevancia las formas del relieve relacionadas con la estructura geológica
hercínica, en donde aparecen procesos activos ligados a procesos gravitacionales, originando formas del relieve
como canchales, coluviones, depósitos de piedemonte y. Debido a lo escarpado de este dominio, apenas existen
infraestructuras humanas, por lo que la interferencia de los procesos activos con las mismas es baja. En el segundo
dominio aparecen formas del relieve originadas por procesos activos relacionados con el encajamiento de la red
fluvial y de sedimentación, pudiendo afectar a infraestructuras humanas. En el tercero aparecen actuaciones
susceptibles de interferir con los procesos activos naturales, provocando efectos adversos para la población.
La información cartográfica obtenida supone la base para un análisis de susceptibilidad espacial de los distintos
peligros de origen geológico, útil para la planificación territorial.The aim of this work is to represent by means of GIS techniques the geomorphological and active geological
processes map of the middle course of the Eria river, located in the southwestern León province, Spain. This study is
based on aerial photointerpretation, bibliographic analysis of previous works, and on the application of GIS
techniques. These techniques were used for the representation of the mapping units, and for analyzing a DTM and
derived maps (slop, aspect, etc.), creating a spatial and attribute database.Three main relief domains were differentiated based on the predominant active geological processes: the domain
of landforms developed on the Palaeozoic metamorphic rocks, the domain of fluvial landforms, and the domain of
anthropogenic landforms. The first one is mainly related to active gravitational processes, but because of the low
human occupation, the interaction with human infrastructures is almost negligible. The second one is mainly related
to incision and sedimentation of the drainage network, interacting with some human infrastructures developed on
the floodplains, alluvial fans and close to the river side. The third one is formed by human elements affecting and
modifying at different levels the strength of the active geological processes.
The resulting map act as a basis for further spatial susceptibility for geological hazards analysis, which is useful
for land use planning
Aplicación de técnicas de teledetección para la caracterización geomorfológica del sector suroccidental de la provincia de León, España
Proporciones aúreas de la mezquita del Cristo de la Luz
Con el objeto de favorecer la formación de los alumnos y reducir al mínimo el trauma que supone cada examen, en la cátedra de Construcción que D. Román Ferreras imparte en la E.I.T.O.P., se solicita de aquellos la presentación de un estudio, que al suponer trabajo personal tiene gran repercusión en la calificación final. De entre los realizados últimamente hemos seleccionado el presente, que contiene aportaciones de indudable interés al conocimiento de nuestro acervo arquitectónico y refleja las posibilidades del análisis armónico como herramientas de diseño
Quantum Magnetic Deflagration in Mn12 Acetate
We report controlled ignition of magnetization reversal avalanches by surface
acoustic waves in a single crystal of Mn12 acetate. Our data show that the
speed of the avalanche exhibits maxima on the magnetic field at the tunneling
resonances of Mn12. Combined with the evidence of magnetic deflagration in Mn12
acetate (Suzuki et al., cond-mat/0506569) this suggests a novel physical
phenomenon: deflagration assisted by quantum tunneling.Comment: 4 figure
Keratitis after Implantation of Intrastromal Corneal Rings with Spontaneous Extrusion of the Segment
Purpose: To report a case of bacterial keratitis in a patient with a history of intrastromal corneal ring segments (INTACS®) implantation to correct keratoconus. Methods: The patient’s history, clinical presentation, pathological analysis and therapeutic management were reviewed. Results: A 36-year-old-man was referred to our department due to decreased vision and intense pain in his left eye, 40 days after INTACS® implantation for keratoconus. Slit-lamp examination revealed epithelial defects and stromal infiltrates in the lower channel without evidence of the inferior ring. The anterior chamber also showed a significant fibrin reaction to hypopyon. A low-tension suture was removed at the site of the incision. Microbiological study of the conjunctival swab was positive for Staphylococcus epidermidis, but the corneal culture was sterile. The patient was treated with topical fortified and systemic antibiotics. The infection slowly resolved, leaving opacity at the inferior segment site. Conclusions: Infectious keratitis following INTACS implantation is an infrequent complication that can have important consequences without suitable and early therapeutic management
Low temperature microwave emission from molecular clusters
We investigate the experimental detection of the electromagnetic radiation
generated in the fast magnetization reversal in Mn12-acetate at low
temperatures. In our experiments we used large single crystals and assemblies
of several small single crystals of Mn12-acetate placed inside a cylindrical
stainless steel waveguide in which an InSb hot electron device was also placed
to detect the radiation. All this was set inside a SQUID magnetometer that
allowed to change the magnetic field and measure the magnetic moment and the
temperature of the sample as the InSb detected simultaneously the radiation
emitted from the molecular magnets. Our data show a sequential process in which
the fast inversion of the magnetic moment first occurs, then the radiation is
detected by the InSb device, and finally the temperature of the sample
increases during 15 ms to subsequently recover its original value in several
hundreds of milliseconds.Comment: changed conten
Quantifying Li-content for compositional tailoring of lithium ferrite ceramics
Owing to their multiple applications, lithium ferrites are relevant materials
for several emerging technologies. For instance, LiFeO2 has been spotted as an
alternative cathode material in Li-ion batteries, while LiFe5O8 is the lowest
damping ferrite, holding promise in the field of spintronics. The Li-content in
lithium ferrites has been shown to greatly affect the physical properties, and
in turn, the performance of functional devices based on these materials.
Despite this, lithium content is rarely accurately quantified, as a result of
the low number of electrons in Li hindering its identification by means of
routine materials characterization methods. In the present work, magnetic
lithium ferrite powders with Li:Fe ratios of 1:1, 1:3 and 1:5 have been
synthesized, successfully obtaining phase-pure materials (LiFeO2 and LiFe5O8),
as well as a controlled mixture of both phases. The powders have been compacted
and subsequently sintered by thermal treatment (Tmax = 1100 {\deg}C) to
fabricate dense pellets which preserve the original Li:Fe ratios. Li-content on
both powders and pellets has been determined by two independent methods: (i)
Rutherford backscattering spectroscopy combined with nuclear reaction analysis
and (ii) Rietveld analysis of powder X-ray diffraction data. With good
agreement between both techniques, it has been confirmed that the Li:Fe ratios
employed in the synthesis are maintained in the sintered ceramics. The same
conclusion is drawn from spatially-resolved confocal Raman microscopy
experiments on regions of a few microns. Field emission scanning electron
microscopy has evidenced the substantial grain growth taking place during the
sintering process - mean particle sizes rise from about 600 nm in the powders
up to 3.8(6) um for dense LiFeO2 and 10(2) um for LiFe5O8 ceramics
Interpenetrated Luminescent Metal-Organic Frameworks based on 1H-Indazole-5-carboxylic Acid
Herein we report the formation and characterization of two novel Zn-based multifunctional metal-organic frameworks (MOFs) based on 1H-indazole-5-carboxylic acid and bipyridine-like linkers, synthesized by soft solvothermal routes. These materials possess isoreticular 2-fold interpenetrated three-dimensional structures that afford a flexible character and allow porosity modulation of the MOFs as confirmed by CO2 sorption measurements. Apart from this attractive structural feature, the MOFs exhibit fascinating luminescent properties involving both luminescence thermometry and long-lasting phosphorescence
Management of fibro-osseous lesions of the craniofacial area: presentation of 19 cases and review of the literature
Introduction: Fibro-osseous lesions constitute a rare benign type of pathology with a non-odontogenic lineage that
affect the craniofacial area. According to Waldrom's classification, these lesions are divided into: fibrous dysplasia
(FD), cemento-ossifying fibroma (COF) and desmoplastic fibroma (DF).
Material and Methods: A retrospective study was performed on patients diagnosed with fibro-osseous lesions of
the craniofacial area at the Hospital Universitario La Fe, Valencia, during 1987-2009. A total of 19 cases were collected: 15 cases compatible with an FD diagnosis, 3 cases with a COF diagnosis and 1 case with a DF diagnosis.
Results: In the differential diagnosis, entities having similar clinical manifestations in the maxillofacial area with
possible involvement of teeth or manifestations present as an asymptomatic radiolucent image should be ruled out.
We hereby present the management and development of patients treated in our hospital for fibro-osseous lesions.
Conclusions: Fibro-osseous lesions share many clinical and radiological characteristics in common, with histological features confirming the nature of the lesion. Management of patients should be individualized and casespecific, assessing the clinical evolution of each case and taking into account the benign nature and growth
behavior of this type of tumors
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