A Low-Cost FPGA-Based Test and Diagnosis Architecture for SRAMs

The continues improvement of manufacturing technologies allows the realization of integrated circuits containing an ever increasing number of transistors. A major part of these devices is devoted to realize SRAM blocks. Test and diagnosis of SRAM circuits are therefore an important challenge for improving quality of next generation integrated circuits. This paper proposes a flexible platform for testing and diagnosis of SRAM circuits. The architecture is based on the use of a low cost FPGA based board allowing high diagnosability while keeping costs at a very low leve

Defective Behaviour of an 8T SRAM Cell with Open Defects

The defective behaviour of an 8T SRAM cell with open defects is analyzed. Full and resistive open defects have been considered in the electrical characterization of the defective cell. Due to the similarity between the classical 6T SRAM cell and the 8T cell, only defects affecting the read port transistors have been considered. In the work, it is shown how an open in a defective cell may influence the correct operation of a victim cell sharing the same read circuitry. Also, it is shown that the sequence of bits written on the defective cell prior to a read action can mask the presence of the defect. Different orders of critical resistance have been found depending on the location of the open defect. A 45nm technology has been used for the illustrative example presented in the wor

Walkway on coastal dunes negatively affects mobility of the spiny–footed lizard Acanthodactylus erythrurus

Las pasarelas en las dunas costeras perjudican la movilidad de la lagartija colirroja Acanthodactylus erythrurus Los sistemas dunares son los ecosistemas más degradados de toda la costa europea y la actividad humana ha causado una profunda transformación en la costa mediterránea de España. En Torredembarra (Tarragona, España) habita una población de lagartija colirroja Acanthodactylus erythrurus en algunas de las dunas naturales y parches de vegetación que aún existen, donde la fauna silvestre coexiste con unas intensas actividades turísticas. Nuestro objetivo fue conocer si las pasarelas instaladas sobre las dunas estaban afectando a la movilidad de la lagartija colirroja. Se comparó la movilidad de lagartijas marcadas entre dos zonas con hábitat similar, pero una con pasarelas y otra sin. Se observó que las pasarelas acortaron las distancias entre reavistamientos consecutivos y que afectaban más a los juveniles de lagartija colirroja que a los adultos. Llegamos a la conclusión de que la pasarela puede estar afectando a las interacciones sociales naturales de la especie.Dune systems are the most degraded ecosystems of the entire European coast, and human activity on the Mediterranean coast of Spain has caused dramatic transformation. In Torredembarra (Tarragona, Spain), a population of spiny–footed lizards Acanthodactylus erythrurus inhabits the few remaining natural dunes and vegetation patches where wildlife coexists with intensive tourism activities. Our aim was to know whether walkways installed across the dunes were affecting the mobility of the spiny–footed lizard. We compared the mobility of marked lizards in two areas with a similar habitat, one with and one without a walkway. We found that the walkway reduced the distances between consecutive resightings, affecting juveniles more than adults. We conclude that the walkway may affect social interactions in the species.Las pasarelas en las dunas costeras perjudican la movilidad de la lagartija colirroja Acanthodactylus erythrurus Los sistemas dunares son los ecosistemas más degradados de toda la costa europea y la actividad humana ha causado una profunda transformación en la costa mediterránea de España. En Torredembarra (Tarragona, España) habita una población de lagartija colirroja Acanthodactylus erythrurus en algunas de las dunas naturales y parches de vegetación que aún existen, donde la fauna silvestre coexiste con unas intensas actividades turísticas. Nuestro objetivo fue conocer si las pasarelas instaladas sobre las dunas estaban afectando a la movilidad de la lagartija colirroja. Se comparó la movilidad de lagartijas marcadas entre dos zonas con hábitat similar, pero una con pasarelas y otra sin. Se observó que las pasarelas acortaron las distancias entre reavistamientos consecutivos y que afectaban más a los juveniles de lagartija colirroja que a los adultos. Llegamos a la conclusión de que la pasarela puede estar afectando a las interacciones sociales naturales de la especie

Absolute magnitudes and kinematics of CP stars from Hipparcos data

The position in the HR diagram and the kinematic characteristics of different kinds of CP stars of the upper main sequence are obtained using the LM method (Luri et al., 1996). Most of the CP stars are main sequence stars occupying the whole width of the sequence. From a kinematic point of view, they belong to the young disk population (ages < 1.5 Gyr). It has also been found that, on kinematic grounds, the behaviour of lambda Bootis stars is similar to the one observed for normal stars of the same spectral range. On the other hand, roAp and noAp stars show the same kinematic characteristics. The peculiar velocity distribution function has been decomposed into a sum of three dimensional gaussians and the presence of Pleiades, Sirius and Hyades moving groups has been clearly established. Finally, a small number of CP stars are found to be high-velocity objects.Comment: 8 pages, 1 figure, to appear in: Proc. of the 26th workshop of the European Working Group on CP stars, eds. P. North, A. Schnell and J. Ziznovsky, Contrib. Astr. Obs. Skalnate Pleso Vol. 27, No

Estudio refractométrico y conoscópico de las gemas facetadas transparentes birrefringentes de la colección del Museu de Geologia de Barcelona

This work is a revision of faceted transparent birrefringent gems detailed in the catalogue of the collection of the Museu de Geologia published in 2000. The process use figures of interference as especially convincing method for a correct identification of these kind of gems. The Conoscope Figueras 93 is especially suitable for a clear and correct observation of figures of interference. The gemmological refractometer has been used for refractometric readings. Key words: Faceted gems, Figures of interference, Conoscope, Birrefringence, Refractometry, Catalogue, Museu de Geologia, Barcelona, Spain.Este trabajo recoge una revisión de las gemas facetadas birrefringentes del Museo de Geología de Barcelona, detalladas en un catálogo publicado en el año 2000. En el proceso de revisión se utilizan las figuras de interferencia como método más convincente para la correcta identificación de este tipo de gemas, estando el conoscopio Figueras 93 especialmente indicado para la mejor observación de estas figuras. Para las lecturas refractométricas se ha usado el refractómetro gemológico. Palabras clave: Gemas facetadas, Figuras de interferencia, Conoscopio, Birrefringencia, Refractometría, Catálogo, Museu de Geologia, Barcelona, España

The spatial relation between the event horizon and trapping horizon

The relation between event horizons and trapping horizons is investigated in a number of different situations with emphasis on their role in thermodynamics. A notion of constant change is introduced that in certain situations allows the location of the event horizon to be found locally. When the black hole is accreting matter the difference in area between the two different horizons can be many orders of magnitude larger than the Planck area. When the black hole is evaporating the difference is small on the Planck scale. A model is introduced that shows how trapping horizons can be expected to appear outside the event horizon before the black hole starts to evaporate. Finally a modified definition is introduced to invariantly define the location of the trapping horizon under a conformal transformation. In this case the trapping horizon is not always a marginally outer trapped surface.Comment: 16 pages, 1 figur