Controlo por fase única de conversores A/D de baixa tensão

Este trabalho apresenta a aplicação de um controlo de fase única a um conversor concorrencial de baixa tensão. Com vista à validação da análise e conclusão teóricas, um conversor concorrencial de 10-bit 4 MS/s foi projectado e simulado. Foi primeiramente simulado com um controlo clássico de 6 fases, e posteriormente com um esquema de fase única. Os resultados de simulação mostram que as características globais são mantidas, apontando para que o uso de esquemas de fase única em conversores de baixa tensão seja uma solução que reduz a complexidade dos sistemas clássicos não sobrepostos.info:eu-repo/semantics/publishedVersio

Follow-up of bone lesions in an experimental multiple myeloma mouse model: description of an in vivo technique using radiography dedicated for mammography.

The evolution of bone lesions in transplantable C57BL/KaLwRjj 5T mouse myeloma (MM) has been followed in vivo. Mice were anaesthetised and a radiograph of the pelvis and hind legs was performed by a radiograph dedicated for mammography. This is the first description of an in vivo technique under experimental conditions whereby the development of bone lesions owing to the MM growth was demonstrated

Power-and-area efficient 14-bit 1.5 MSample/s two-stage algorithmic ADC based on a mismatch-insensitive MDAC

IEEE International Symposium on Circuits and Systems, pp. 220 – 223, Seattle, EUAThis paper presents a 14-bit 1.5 MSample/s two-stage algorithmic ADC with a power-and-area efficiency better than 0.5 pJmm2 per conversion. This competes with the most efficient architectures available today namely, ΣΔ and self-calibrated pipeline. The 2 stages of the ADC are based on a new 1.5-bit mismatch-insensitive MDAC and simulations demonstrate that a THD of –79 dB and an ENOB better than 12 bits can be reached without self-calibration

Validation and assessment of variant calling pipelines for next-generation sequencing

Background: The processing and analysis of the large scale data generated by next-generation sequencing (NGS) experiments is challenging and is a burgeoning area of new methods development. Several new bioinformatics tools have been developed for calling sequence variants from NGS data. Here, we validate the variant calling of these tools and compare their relative accuracy to determine which data processing pipeline is optimal. Results: We developed a unified pipeline for processing NGS data that encompasses four modules: mapping, filtering, realignment and recalibration, and variant calling. We processed 130 subjects from an ongoing whole exome sequencing study through this pipeline. To evaluate the accuracy of each module, we conducted a series of comparisons between the single nucleotide variant (SNV) calls from the NGS data and either gold-standard Sanger sequencing on a total of 700 variants or array genotyping data on a total of 9,935 single-nucleotide polymorphisms. A head to head comparison showed that Genome Analysis Toolkit (GATK) provided more accurate calls than SAMtools (positive predictive value of 92.55% vs. 80.35%, respectively). Realignment of mapped reads and recalibration of base quality scores before SNV calling proved to be crucial to accurate variant calling. GATK HaplotypeCaller algorithm for variant calling outperformed the UnifiedGenotype algorithm. We also showed a relationship between mapping quality, read depth and allele balance, and SNV call accuracy. However, if best practices are used in data processing, then additional filtering based on these metrics provides little gains and accuracies of >99% are achievable. Conclusions: Our findings will help to determine the best approach for processing NGS data to confidently call variants for downstream analyses. To enable others to implement and replicate our results, all of our codes are freely available at http://metamoodics.org/wes

Design and testing of a radiation hardened 13-bit 80 MS/s pipeline ADC implemented in a 90nm standard CMOS process

Second International Workshop on Analog and Mixed Signal Integrated Circuits for Space Applications (AMICSA 2008), Sintra, Portugal, Setembro de 200

Light absorption properties of southeastern Bering Sea waters: Analysis, parameterization and implications for remote sensing.

The absorption coefficients of phytoplankton (aPHY(λ)), non-algal particles (NAP) (aNAP(λ)) and colored dissolved organic matter (CDOM) (aCDOM(λ)) were investigated and parameterized in the southeastern Bering Sea during July 2008. The absorption coefficients were well structured with respect to hydrographic and biogeochemical characteristics of the shelf. The highest values of aPHY(443) were observed offshore and the lowest values of aPHY(443) were found in the coastal domain, a low productivity region associated with limited macronutrients. Values of aDG(λ) (aCDOM(λ) + aNAP(λ)) revealed an east–west gradient pattern with higher values in the coastal domain, and lower values in the outer domain. Lower chlorophyll specific aPHY(λ) (a*PHY(λ)) observed relative to middle and lower latitude waters indicated a change in pigment composition and/or package effect, which was consistent with phytoplankton community structure. aCDOM(λ) was the dominant light absorbing coefficient at all wavelengths examined except at 676 nm. Modeling of remote-sensing reflectance (Rrs(λ)) and the diffuse attenuation coefficient (Kd(λ)) from inherent optical properties revealed the strong influence of aCDOM(λ) on Rrs(λ) and Kd(λ). Good optical closure was achieved between modeled and radiometer measured Rrs(λ) and Kd(λ) with average percent difference of less than 25% and 19% respectively, except at red wavelengths. The aCDOM(λ) accounted for > 50% of Kd(λ) which was vertically variable. Chlorophyll-a calculated by the NASA standard chlorophyll-a algorithm (OC4.v6) was overestimated due to higher aCDOM(λ) and underestimated due to lower a*PHY(λ) at low and high concentrations of chlorophyll-a, respectively

Seismic tomographic imaging of the Eastern Mediterranean Mantle: Implications for terminal-stage subduction, the uplift of Anatolia, and the development of the North Anatolian Fault

The Eastern Mediterranean captures the eastwest transition from active subduction of Earth'soldest oceanic lithosphere to continental collision, making it an ideal location to study terminalstagesubduction. Asthenospheric or subductionrelated processes are the main candidates for the region's ∼2kmuplift and Miocene volcanism; however, their relative importance is debated. To address these issues, wepresent new P and S wave relative arrivaltime tomographic models that reveal fast anomalies associatedwith an intact Aegean slab in the west, progressing to a fragmented, partially continental, Cyprean slabbelow central Anatolia. We resolve a gap between the Aegean and Cyprean slabs, and a horizontal tear in theCyprean slab below the Central Anatolian Volcanic Province. Below eastern Anatolia, the completelydetached “Bitlis” slab is characterized by fast wave speeds at ∼500 km depth. Assuming slab sinkingrates mirror ArabiaAnatolia convergence rates, the Bitlis slab's location indicates an Oligocene (∼26 Ma)breakoff. Results further reveal a strong velocity contrast across the North Anatolian Fault likelyrepresenting a 40–60 km decrease in lithospheric thickness from the Precambrian lithosphere north of thefault to a thinned Anatolian lithosphere in the south. Slow uppermostmantle wave speeds below activevolcanoes in eastern Anatolia, and ratios of P to S wave relative traveltimes, indicate a thin lithosphere andmelt contributions. Positive central and eastern Anatolian residual topography requires additional supportfrom hot/buoyant asthenosphere to maintain the 1–2 km elevation in addition to an almost absentlithospheric mantle. Smallscale fast velocity structures in the shallow mantle above the Bitlis slab maytherefore be drips of Anatolian lithospheric mantle

Light-particle emission from the fissioning nuclei 126Ba, 188Pt and (266,272,278)/110: theoretical predictions and experimental results

We present a comparison of our model treating fission dynamics in conjunction with light-particle (n, p, alpha) evaporation with the available experimental data for the nuclei 126Ba, 188Pt and three isotopes of the element Z=110. The dynamics of the symmetric fission process is described through the solution of a classical Langevin equation for a single collective variable characterizing the nuclear deformation along the fission path. A microscopic approach is used to evaluate the emission rates for pre-fission light particles. Entrance-channel effects are taken into account by generating an initial spin distribution of the compound nucleus formed by the fusion of two deformed nuclei with different relative orientations

Microstructure and magneto-dielectric properties of the chitosan/gelatin-YIG biocomposites

This work is devoted to the preparation of yttrium iron garnet (YIG) ferrimagnetic biocomposites based in biodegradable chitosan and gelatin. The aim was to produce composite films containing controlled amounts of YIG to obtain a new biological material with magneto-dielectric features. Structural characterization of the biocomposites was made by scanning electron microscopy, X-ray diffraction, infrared absorption spectroscopy and thermal analysis, while the dielectric and magnetic properties were obtained from dielectric spectroscopy and magnetic hysteresis loops, respectively. The versatility of the films obtained makes them possible candidates for use as biomaterials or electronic device

Imaging slab-transported fluids and their deep dehydration from seismic velocity tomography in the Lesser Antilles subduction zone

Volatiles play a pivotal role in subduction zone evolution, yet their pathways remain poorly constrained. Studying the Lesser Antilles subduction zone can yield new constraints, where old oceanic lithosphere formed by slow-spreading subducts slowly. Here we use local earthquakes recorded by the temporary VoiLA (Volatile recycling in the Lesser Antilles) deployment of ocean-bottom seismometers in the fore- and back-arc to characterize the 3-D seismic structure of the north-central Lesser Antilles subduction zone. Along the slab top, mapped based on seismicity, we find low Vp extending to 130–150 km depth, deeper than expected for magmatic oceanic crust. The slab\u27s most prominent, elevated Vp/Vs anomalies are beneath the fore- and back-arc offshore Guadeloupe and Dominica, where two subducted fracture zones lie with the obliquely subducting boundary between Proto-Caribbean and Equatorial Atlantic lithosphere. These structures, therefore, enhance hydration of the oceanic lithosphere as it forms and evolves and the subsequent dehydration of mantle serpentinite when subducted. Above the slab, we image the asthenosphere wedge as a high Vp/Vs and moderate Vp feature, indicating slab-dehydrated fluids rising through the overlying cold boundary layer that might induce melting further to the west. Our results provide new evidence for the impact of spatially-variable oceanic plate formation processes on slab dehydration and mantle wedge volatile transfer that ultimately impact volcanic processes at the surface, such as the relatively high magmatic output observed on the north-central islands in the Lesser Antilles