Detección prenatal de anomalías del sistema nervioso central

ResumenLas anomalías del sistema nervioso central corresponden a un grupo frecuente de malformaciones congénitas; y el ultrasonido prenatal es la herramienta preferida para su pesquisa durante la gestación. El objetivo del presente artículo es proponer dos grupos relevantes de estructuras a ser incluidas en el examen rutinario de segundo trimestre, con el objetivo de maximizar la detección de malformaciones cerebrales.SummaryCentral nervous system defects are some of the most common congenital anomalies and ultrasound is the preferred modality to depict them during pregnancy. The scope of this article is to propose two relevant groups of midline structures, to be included in the basic examination in order to maximize detection of cerebral malformation

Ordering kinetics of stripe patterns

We study domain coarsening of two dimensional stripe patterns by numerically solving the Swift-Hohenberg model of Rayleigh-Benard convection. Near the bifurcation threshold, the evolution of disordered configurations is dominated by grain boundary motion through a background of largely immobile curved stripes. A numerical study of the distribution of local stripe curvatures, of the structure factor of the order parameter, and a finite size scaling analysis of the grain boundary perimeter, suggest that the linear scale of the structure grows as a power law of time with a craracteristic exponent z=3. We interpret theoretically the exponent z=3 from the law of grain boundary motion.Comment: 4 pages, 4 figure

Primera versión española del NEPSY para la evaluación neuropsicológica del desarrollo en una muestra de niños españoles

All the subtests of the first Spanish language version of the NEPSY were administered to a sample of 415 children aged 3 to 12 years old: 193 boys and 222 girls. For statistical analysis, the sample was divided into two groups: one comprising 98 children aged 3-4, and the other 317 children aged 5-12. First, the adjustment of the distribution of the different items of this Spanish version of the NEPSY subtests to the normal curve was checked. The usefulness of these subtests to assess the level of children’s development according to their chronological age was then tested using regression analysis. Finally, we checked that the raw scores on the subtest items of this Spanish version ofthe NEPSY differed significantly between 3 and 4 year olds and between 5 and 6 year olds: in each age pair, the mean scores of the older group increased inaccuracy and decreased in runtime and errors.Se administran todos los subtests de la primera versión en castellano del NEPSY a una muestra de 415 niños de 3 a 12 años de edad: 193 varones y 222 niñas. Para las tareas estadísticas, se separan en dos grupos: uno de 98 niños de 3-4 años y otro de 317 de 4-12 años. En primer lugar, se comprueba el ajuste de las distribuciones de las distintas variables de los subtest de esta versión española del NEPSY a la curva normal. Posteriormente se comprueba la utilidad de estos para verificar el nivel de desarrollo de los niños por su edad cronológica, mediante un análisis de regresión. Finalmente, se verifica que las diferencias en las puntuaciones directas de las distintas variables de los subtestsde esta versión española del NEPSY, entre los niños de 3 y 4 años y entre losde 5 y 6 años, son estadísticamente significativas, de forma que ambos grupos de niños mayores aumentan las medias en exactitud y disminuyen las del tiempo de ejecución y los errores en las diferentes tareas

A phenomenological model of weakly damped Faraday waves and the associated mean flow

A phenomenological model of parametric surface waves (Faraday waves) is introduced in the limit of small viscous dissipation that accounts for the coupling between surface motion and slowly varying streaming and large scale flows (mean flow). The primary bifurcation of the model is to a set of standing waves (stripes, given the functional form of the model nonlinearities chosen here). Our results for the secondary instabilities of the primary wave show that the mean flow leads to a weak destabilization of the base state against Eckhaus and Transverse Amplitude Modulation instabilities, and introduces a new longitudinal oscillatory instability which is absent without the coupling. We compare our results with recent one dimensional amplitude equations for this system systematically derived from the governing hydrodynamic equations.Comment: Complete paper with embedded figures (PostScript, 3 Mb) http://www.csit.fsu.edu/~vinals/mss/jmv1.p

Filtering directory lookups in CMPs

Coherence protocols consume an important fraction of power to determine which coherence action should take place. In this paper we focus on CMPs with a shared cache and a directory-based coherence protocol implemented as a duplicate of local caches tags. We observe that a big fraction of directory lookups produce a miss since the block looked up is not cached in any local cache. We propose to add a filter before the directory lookup in order to reduce the number of lookups to this structure. The filter identifies whether the current block was last accessed as a data or as an instruction. With this information, looking up the whole directory can be avoided for most accesses. We evaluate the filter in a CMP with 8 in-order processors with 4 threads each and a memory hierarchy with a shared L2 cache.We show that a filter with a size of 3% of the tag array of the shared cache can avoid more than 70% of all comparisons performed by directory lookups with a performance loss of just 0.2% for SPLASH2 and 1.5% for Specweb2005. On average, the number of 15-bit comparisons avoided per cycle is 54 out of 77 for SPLASH2 and 29 out of 41 for Specweb2005. In both cases, the filter requires less than one read of 1 bit per cycle.Postprint (published version

Modeling of Dislocation Structures in Materials

A phenomenological model of the evolution of an ensemble of interacting dislocations in an isotropic elastic medium is formulated. The line-defect microstructure is described in terms of a spatially coarse-grained order parameter, the dislocation density tensor. The tensor field satisfies a conservation law that derives from the conservation of Burgers vector. Dislocation motion is entirely dissipative and is assumed to be locally driven by the minimization of plastic free energy. We first outline the method and resulting equations of motion to linear order in the dislocation density tensor, obtain various stationary solutions, and give their geometric interpretation. The coupling of the dislocation density to an externally imposed stress field is also addressed, as well as the impact of the field on the stationary solutions.Comment: RevTeX, 19 pages. Also at http://www.scri.fsu.edu/~vinals/jeff1.p

Analysis of network-on-chip topologies for cost-efficient chip multiprocessors

Abstract not availableMarta Ortín-Obón, Darío Suárez-Gracia, María Villarroya-Gaudó, Cruz Izu, Víctor Viñals-Yúfer

PeRISCVcope: a tiny teaching-oriented RISC-V interpreter

The fast advances of computer systems translate into a growing demand of methodologies and tools to introduce those novelties into classes. Among the plethora of those advances, virtualization has become an essential technology in almost every relevant system stack, from connected cars to hyperscaled cloud servers. However, introducing those technologies into the classroom remains a challenging task because of the huge complexity of their software components that may hinder the learning process of students. peRISCVcope aims to help in this area by proposing a tiny yet powerful interpreter to dig into virtualization technologies, such as the implementation of trap&emulate hypervisors. With less than 2,000 lines of code, and thanks to the conciseness of the RV32I base instruction set of RISC-V, peRISCVcope enables students to make virtualization knowledge their own. This paper presents our experiences developing and testing a virtualization laboratory where students implement parts of an interpreter. After the practical experience, peRISCVcope has been proved as a useful pedagogical tool, and, most importantly, students have positively rated the experience

Creació d’unitats formatives i la seva programació per al mòdul de Pedra Natural

En el centre on es van realitzar les pràctiques es va estar, bàsicament, amb alumnes que cursaven el Cicle Formatiu de Grau Mitjà (CFGM) d’Obres de la Construcció de la família d’Edificació i Obra Civil. Aquest Cicle Formatiu durant aquest curs 2011/2012 s’ha impartit en el format que marca la Llei Orgànica General del Sistema Educatiu de 3 d’octubre del 1990 (LOGSE). Malgrat això, l’any vinent s’haurà d’impartir segons les pautes que marca la nova llei d’educació, la Llei Orgànica de l’Educació del 3 de maig del 2006 (LOE). Amb les Hores de Lliure Disposició dels centres docents (HLLD) que marca la normativa, el centre, quan va començar a impartir aquest cicle formatiu, va decidir invertir-les en la creació d’un nou crèdit: el crèdit de Pedra Natural. Un crèdit únic, que només s’imparteix en aquest centre docent. Amb el canvi de normativa, aquest també és objecte de canvis, i aquests són l’objectiu principal d’aquest Treball Final de Màster (TFM), l'adaptació d’aquest crèdit a un nou mòdul. Per tant, s’ha fet la programació del nou mòdul de Pedra Natural i el disseny del seu currículum, com la creació de 3 noves Unitats Formatives (UF), amb els seus Resultats d’Aprenentatge (RA), Criteris d’Avaluació (CA) i Continguts (C). S’ha aprofitat també per introduir en el currículum continguts d’especial interès en la actualitat, com la rehabilitació o el disseny. Finalment, s’han dissenyat les Activitats d’Ensenyament – Aprenentatge d’un Nucli Formatiu (NF). Per al disseny d’aquestes activitats s’ha fet servir un mètode d’innovació docent, el mètode del puzle de Aronson. Mètode el qual treballa el constructivisme i l’aprenentatge cooperatiu. Dins d’aquestes activitats s’hi ha englobat una sortida al Museu de Geologia Valentí Masachs de la Escola Politècnica Superior d’Enginyeria de Manresa (EPSEM) de la Universitat Politècnica de Catalunya (UPC)

L2C2: Last-level compressed-contents non-volatile cache and a procedure to forecast performance and lifetime

Several emerging non-volatile (NV) memory technologies are rising as interesting alternatives to build the Last-Level Cache (LLC). Their advantages, compared to SRAM memory, are higher density and lower static power, but write operations wear out the bitcells to the point of eventually losing their storage capacity. In this context, this paper presents a novel LLC organization designed to extend the lifetime of the NV data array and a procedure to forecast in detail the capacity and performance of such an NV-LLC over its lifetime. From a methodological point of view, although different approaches are used in the literature to analyze the degradation of an NV-LLC, none of them allows to study in detail its temporal evolution. In this sense, this work proposes a forecasting procedure that combines detailed simulation and prediction, allowing an accurate analysis of the impact of different cache control policies and mechanisms (replacement, wear-leveling, compression, etc.) on the temporal evolution of the indices of interest, such as the effective capacity of the NV-LLC or the system IPC. We also introduce L2C2, a LLC design intended for implementation in NV memory technology that combines fault tolerance, compression, and internal write wear leveling for the first time. Compression is not used to store more blocks and increase the hit rate, but to reduce the write rate and increase the lifetime during which the cache supports near-peak performance. In addition, to support byte loss without performance drop, L2C2 inherently allows N redundant bytes to be added to each cache entry. Thus, L2C2+N, the endurance-scaled version of L2C2, allows balancing the cost of redundant capacity with the benefit of longer lifetime. For instance, as a use case, we have implemented the L2C2 cache with STT-RAM technology. It has affordable hardware overheads compared to that of a baseline NV-LLC without compression in terms of area, latency and energy consumption, and increases up to 6-37 times the time in which 50% of the effective capacity is degraded, depending on the variability in the manufacturing process. Compared to L2C2, L2C2+6 which adds 6 bytes of redundant capacity per entry, that means 9.1% of storage overhead, can increase up to 1.4-4.3 times the time in which the system gets its initial peak performance degraded