310 resultados para 5100


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The Amundsen Sea Embayment (ASE) drains approximately 35% of the West Antarctic Ice Sheet (WAIS) and is one of the most rapidly changing parts of the cryosphere. In order to predict future ice-sheet behaviour, modellers require long-term records of ice-sheet melting to constrain and build confidence in their simulations. Here, we present detailed marine geological and radiocarbon data along three palaeo-ice stream tributary troughs in the western ASE to establish vital information on the timing of deglaciation of the WAIS since the Last Glacial Maximum (LGM). We have undertaken multi-proxy analyses of the cores (core description, shear strength, x-radiographs, magnetic susceptibility, wet bulk density, total organic carbon/nitrogen, carbonate content and clay mineral analyses) in order to: (1) characterise the sedimentological facies and depositional environments; and (2) identify the horizon(s) in each core that would yield the most reliable age for deglaciation. In accordance with previous studies we identify three key facies, which offer the most reliable stratigraphies for dating deglaciation by recording the transition from a grounded ice sheet to open marine environments. These facies are: i) subglacial, ii) proximal grounding-line, and iii) seasonal open-marine. In addition, we incorporate ages from other facies (e.g., glaciomarine diamictons deposited at some distance from the grounding line, such as glaciogenic debris flows and iceberg rafted diamictons and turbates) into our deglacial model. In total, we have dated 78 samples (mainly the acid insoluble organic (AIO) fraction, but also calcareous foraminifers), which include 63 downcore and 15 surface samples. Through careful sample selection prior to dating, we have established a robust deglacial chronology for this sector of the WAIS. Our data show that deglaciation of the western ASE was probably underway as early as 22,351 calibrated years before present (cal 44 yr BP), reaching the mid-shelf by 13,837 cal yr BP and the inner shelf to within c.10-12 km of the present ice shelf front between 12,618 and 10,072 cal yr BP. The deglacial steps in the western ASE broadly coincide with the rapid rises in sea-level associated with global meltwater pulses 1a and 1b, although given the potential dating uncertainty, additional, more precise ages are required before these findings can be fully substantiated. Finally, we show that the rate of ice-sheet retreat increased across the deep (up to1,600 m) basins of the inner shelf, highlighting the importance of reverse slope and pinning points in accelerated phases of deglaciation.

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Digital Image Processing is a rapidly evolving eld with growing applications in Science and Engineering. It involves changing the nature of an image in order to either improve its pictorial information for human interpretation or render it more suitable for autonomous machine perception. One of the major areas of image processing for human vision applications is image enhancement. The principal goal of image enhancement is to improve visual quality of an image, typically by taking advantage of the response of human visual system. Image enhancement methods are carried out usually in the pixel domain. Transform domain methods can often provide another way to interpret and understand image contents. A suitable transform, thus selected, should have less computational complexity. Sequency ordered arrangement of unique MRT (Mapped Real Transform) coe cients can give rise to an integer-to-integer transform, named Sequency based unique MRT (SMRT), suitable for image processing applications. The development of the SMRT from UMRT (Unique MRT), forward & inverse SMRT algorithms and the basis functions are introduced. A few properties of the SMRT are explored and its scope in lossless text compression is presented.

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Ethanol, classified as a drug, affects the central nervous system, and its consumption has been linked to the development of several behaviours including tolerance and dependence. Alcohol tolerance is defined as the need for higher doses of alcohol to induce the same changes observed in the initial exposure or where repetitive exposures of the same alcohol dose induce a lower response. Ethanol has been shown to interact with numerous targets and ultimately influence both short and long term adaptation at the cellular and molecular level in brain [1]. These adaptation processes are likely to involve signalling molecules: our work has focussed on G proteins gene expression. Using both wild type and several mutant fruit fly (Drosophila melanogaster) as a model for behaviour and molecular studies, we observed significant increases in sedation time (ST50) in response to alcohol (P<0.001) Fig.A. We also observed a consistent and significant decrease of Gq protein mRNA expression in Drosophila dUNC and DopR2 mutants chronically exposed to alcohol (*P<0.05). Fig B. Method: Six male flies were observed in drosophila polystyrene 25 x 95mm transparent vial in between cotton plugs. To the top plug, 500uL of 100% ethanol was added. Time till 50% of the flies were sedated was recorded on each day following the schedule. Fig. C (n=4-6). Using RT-PCR, we also quantified G protein mRNA expression levels one hour post initial 30 minutes of ethanol expression on day 1 and day 3 relative to expression in naïve flies.(n=2) [A] Increase in sedation time indicative of tolerance in different mutant lines and wild type flies. Six male flies were used in each experiment and (n= 4-6. ***P<0.001 unpaired t tests). [B] RT-PCR results showing significant reduction in Gq mRNA in flies chronically exposed to alcohol. (n=2. *P<0.05) [C] Alcohol exposure schedule. (1) Kaun K.R., R. Azanchi, Z. Maung, J. Hirsh, U. Heberlein. (2011). A Drosophila model for alcohol reward. Nature Neuroscience. 14 (5), 612–619.

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El Comité Español de Representantes de Personas con Discapacidad (Cermi) presenta, un año más, su informe sobre discapacidad y derechos humanos, que analiza la aplicación en España de la Convención Internacional sobre los Derechos Humanos de este colectivo. Al igual que en ediciones anteriores, se ha tomado como fuente las consultas y denuncias de vulneración de derechos de personas con discapacidad recibidas ante el propio Cermi; las acciones emprendidas como consecuencia del trabajo propio de la entidad; las consultas y denuncias de personas y entidades colaboradoras, tanto del movimiento asociativo como pertenecientes a distintos ámbitos jurídicos; y las noticias publicadas en prensa o difundidas en redes sociales, así como la actividad de los diferentes operadores jurídicos.

El informe, correspondientea 2014, consta de cuatro partes. El capítulo central y el más extenso analiza la efectividad de los derechos de las personas con discapacidad, siguiendo el orden de los artículos de la Convención. El examen incorpora una síntesis del artículo, seguido de una descripción de la situación de las personas con discapacidad en ese ámbito; las vulneraciones o denuncias recibidas por el Cermi o por otros operadores jurídicos; los avances en el cumplimiento de los derechos, así como propuestas de mejora. El siguiente apartado del documento analiza los informes con consultas o quejas en torno a esta cuestión presentados por la Oficina de Atención a la Discapacidad (OADIS), y los Defensores del Pueblo estatal y autonómicos. Finalmente, se recogen dos observaciones del Comité de los Derechos de las Personas con Discapacidad de Naciones relativas al igual reconocimiento como persona ante la ley, y a la accesibilidad.

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The Atacama Desert has been pointed out as one of the places on earth where the highest surface irradiance may occur. This area is characterized by its high altitude, prevalent cloudless conditions and relatively low columns of ozone and water vapor. Aimed at the characterization of the solar spectrum in the Atacama Desert, we carried out in February-March 2015 ground-based measurements of the spectral irradiance (from the ultraviolet to the near infrared) at seven locations that ranged from the city of Antofagasta (on the southern pacific coastline) to the Chajnantor Plateau (5,100 m altitude). Our spectral measurements allowed us to retrieve the total ozone column, the precipitable water, and the aerosol properties at each location. We found that changes in these parameters, as well as the shorter optical path length at high-altitude locations, lead to significant increases in the surface irradiance with the altitude. Our measurements show that, in the range 0-5100 m altitude, surface irradiance increases with the altitude by about 27% in the infrared range, 6% in the visible range, and 20% in the ultraviolet range. Spectral measurements carried out at the Izana Observatory (Tenerife, Spain), in Hannover (Germany) and in Santiago (Chile), were used for further comparisons.

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Digital rock physics combines modern imaging with advanced numerical simulations to analyze the physical properties of rocks -- In this paper we suggest a special segmentation procedure which is applied to a carbonate rock from Switzerland -- Starting point is a CTscan of a specimen of Hauptmuschelkalk -- The first step applied to the raw image data is a nonlocal mean filter -- We then apply different thresholds to identify pores and solid phases -- Because we are aware of a nonneglectable amount of unresolved microporosity we also define intermediate phases -- Based on this segmentation determine porositydependent values for the pwave velocity and for the permeability -- The porosity measured in the laboratory is then used to compare our numerical data with experimental data -- We observe a good agreement -- Future work includes an analytic validation to the numerical results of the pwave velocity upper bound, employing different filters for the image segmentation and using data with higher resolution

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Dissertação de Mestrado apresentada no ISPA – Instituto Universitário para obtenção do grau de Mestre em Psicologia especialidade em Psicologia Social e das Organizações