U-Pb zircon in situ dating with LA-MC-ICP-MS using a mixed detector configuration

The LA-MC-ICP-MS method applied to U-Pb in situ dating is still rapidly evolving due to improvements in both lasers and ICP-MS. To test the validity and reproducibility of the method, 5 different zircon samples, including the standard Temora-2, ranging in age between 2.2 Ga and 246 Ma, were dated using both LA-MC-ICP-MS and SHRIMP. The selected zircons were dated by SHRIMP and, after gentle polishing, the laser spot was driven to the same site or on the same zircon phase with a 213 nm laser microprobe coupled to a multi-collector mixed system. The data were collected with a routine spot size of 25 μm and, in some cases, of 15 and 40 μm. A careful cross-calibration using a diluted U-Th-Pb solution to calculate the Faraday reading to counting rate conversion factors and the highly suitable GJ-1 standard zircon for external calibrations were of paramount importance for obtaining reliable results. All age results were concordant within the experimental errors. The assigned age errors using the LA-MC-ICP-MS technique were, in most cases, higher than those obtained by SHRIMP, but if we are not faced with a high resolution stratigraphy, the laser technique has certain advantages.

Results from the HST/COS FUV detector "lifetime move"

We describe the planning, implementation, and initial results of the first planned move of the default position of spectra on the Hubble Space Telescope's Cosmic Origins Spectrograph (COS) Far Ultraviolet (FUV) cross-delay line detector. This was motivated by the limited amount of charge that can be extracted from the microchannel plate due to gain sag at any one position. Operations at a new location began on July 23, 2012, with a shift of the spectrum by +3.5"(corresponding to ~ 41 pixels or ~ 1 mm) in a direction orthogonal to the spectral dispersion. Operation at this second "lifetime position" allows for spectra to be collected which are not affected by detector artifacts and loss of sensitivity due to gain sag. We discuss programs designed to enable operations at the new lifetime position; these include determinations of operational high voltage, measuring walk corrections and focus, confirming spectrum placement and aperture centering, and target acquisition performance. We also present results related to calibration of the new lifetime position, including measurements of spectral resolution and wavelength calibration, flux and flat field calibration, carryover of time-dependent sensitivity monitoring, and operations with the Bright Object Aperture (BOA).

Genome sequence of Xanthomonas fuscans subsp. fuscans strain 4834-R reveals that flagellar motility is not a general feature of xanthomonads

Abstract Background Xanthomonads are plant-associated bacteria responsible for diseases on economically important crops. Xanthomonas fuscans subsp. fuscans (Xff) is one of the causal agents of common bacterial blight of bean. In this study, the complete genome sequence of strain Xff 4834-R was determined and compared to other Xanthomonas genome sequences. Results Comparative genomics analyses revealed core characteristics shared between Xff 4834-R and other xanthomonads including chemotaxis elements, two-component systems, TonB-dependent transporters, secretion systems (from T1SS to T6SS) and multiple effectors. For instance a repertoire of 29 Type 3 Effectors (T3Es) with two Transcription Activator-Like Effectors was predicted. Mobile elements were associated with major modifications in the genome structure and gene content in comparison to other Xanthomonas genomes. Notably, a deletion of 33 kbp affects flagellum biosynthesis in Xff 4834-R. The presence of a complete flagellar cluster was assessed in a collection of more than 300 strains representing different species and pathovars of Xanthomonas. Five percent of the tested strains presented a deletion in the flagellar cluster and were non-motile. Moreover, half of the Xff strains isolated from the same epidemic than 4834-R was non-motile and this ratio was conserved in the strains colonizing the next bean seed generations. Conclusions This work describes the first genome of a Xanthomonas strain pathogenic on bean and reports the existence of non-motile xanthomonads belonging to different species and pathovars. Isolation of such Xff variants from a natural epidemic may suggest that flagellar motility is not a key function for in planta fitness.

Monte Carlo Semi-Empirical Model for Si(Li) X-Ray Detector: Differences between Nominal and Fitted Parameters.

A detailed characterization of a X-ray Si(Li) detector was performed to obtain the energy dependence of efficiency in the photon energy range of 6.4 - 59.5 keV. which was measured and reproduced by Monte Carlo (MC) simulations. Significant discrepancies between MC and experimental values were found when lhe manufacturer parameters of lhe detector were used in lhe simulation. A complete Computerized Tomagraphy (CT) detector scan allowed to find the correct crystal dimensions and position inside the capsule. The computed efficiencies with the resulting detector model differed with the measured values no more than 10% in most of the energy range.

Positron annihilation spectroscopy techniques applied to the study of an HPGe detector.

Doppler Broadening Spectroscopy of the large Ge crystal of an HPGe detector was perforrned using positrons from pair production of 6.13 MeV ϒ-rays from the 19F(p,αϒ) 16O reaction. Two HPGe detectors facing opposite sides of the Ge crystal acting as target provided both coincidence and singles spectra. Changes in the shape of the annihilation peak were observed when the high voltage applied to the target detector was switched on or off, amounting to somewhat less than 20% when the areas of equivalent energy intervals in the corresponding normalized spectra are compared.

SED Stroop Effect Detector prototype

[ES] El Detector de Efectos Stroop (SED - Stroop Effect Detector), es una herramienta informática de asistencia, desarrollada a través del programa de investigación de Desarrollo Tecnológico Social de la Universidad de Las Palmas de Gran Canaria, que ayuda a profesionales del sector neuropsicológico a identificar problemas en la corteza orbitofrontal de un individuo, usándose para ello la técnica ideada por Schenker en 1998. Como base metodológica, se han utilizado los conocimientos adquiridos en las diferentes materias de la adaptación al grado en Ingeniería Informática como Gestión del Software, Arquitectura del Software y Desarrollo de Interfaces de Usuario así como conocimiento adquirido con anterioridad en asignaturas de Programación e Ingeniería del Software I y II. Como para realizar este proyecto sólo el conocimiento informático no era suficiente, he realizado una labor de investigación acerca del problema, teniendo que recopilar información de otros documentos científicos que abordan el tema, consultas a profesionales del sector como son el Doctor Don Ayoze Nauzet González Hernández, neurólogo del hospital Doctor Negrín de Las Palmas de Gran Canaria y el psicólogo Don José Manuel Rodríguez Pellejero que habló de este problema en clase del máster de Formación del Profesorado y que actualmente estoy cursando. Este trabajo presenta el test de Stroop con las dos versiones de Schenker: RCN (Reading Color Names) y NCW (Naming Colored Words). Como norma general, ambas pruebas presentan ante los sujetos estudios palabras (nombres de colores) escritas con la tinta de colores diferentes. De esta forma, el RCN consiste en leer la palabra escrita omitiendo la tonalidad de su fuente e intentando que no nos influya. Por el contrario, el NCW requiere enunciar el nombre del color de la tinta con la que está escrita la palabra sin que nos influya que ésta última sea el nombre de un color.

A subpixel edge detector applied to aortic dissection detection

[EN] The aortic dissection is a disease that can cause a deadly situation, even with a correct treatment. It consists in a rupture of a layer of the aortic artery wall, causing a blood flow inside this rupture, called dissection. The aim of this paper is to contribute to its diagnosis, detecting the dissection edges inside the aorta. A subpixel accuracy edge detector based on the hypothesis of partial volume effect is used, where the intensity of an edge pixel is the sum of the contribution of each color weighted by its relative area inside the pixel. The method uses a floating window centred on the edge pixel and computes the edge features. The accuracy of our method is evaluated on synthetic images of different hickness and noise levels, obtaining an edge detection with a maximal mean error lower than 16 percent of a pixel.

Caracterización computacional de un detector de germanio hiperpuro de rango extendido (HPGe- XtRa) con simulación Montecarlo y optimización con un algoritmo evolutivo

Máster Universitario en Sistemas Inteligentes y Aplicaciones Numéricas en Ingeniería (SIANI)

A comparison of face and facial feature detectors based on the viola-jones general object detection framework

[EN]The human face provides useful information during interaction; therefore, any system integrating Vision- BasedHuman Computer Interaction requires fast and reliable face and facial feature detection. Different approaches have focused on this ability but only open source implementations have been extensively used by researchers. A good example is the Viola–Jones object detection framework that particularly in the context of facial processing has been frequently used.

Combining face and facial feature detectors for face detection performance improvement

[EN]In this paper, we experimentally study the combination of face and facial feature detectors to improve face detection performance. The face detection problem, as suggeted by recent face detection challenges, is still not solved. Face detectors traditionally fail in large-scale problems and/or when the face is occluded or di erent head rotations are present. The combination of face and facial feature detectors is evaluated with a public database. The obtained results evidence an improvement in the positive detection rate while reducing the false detection rate. Additionally, we prove that the integration of facial feature detectors provides useful information for pose estimation and face alignment.