Geiger-Mode Avalanche Photodiodes in Particle Detection

It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite sensitivity and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection remains still unexplored. In this contribution, we are going to expose the different steps that we have taken in order to prove the efficiency of Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present an array of pixels of 1mmx1mm fabricated with a standard CMOS technology for characterization in a test beam.Comment: 7 pages, 2 figures, Proceedings of LCWS1

First-principles predictions of low-energy phases of multiferroic BiFeO3

We used first-principles methods to perform a systematic search for potentially-stable phases of multiferroic BiFeO3. We considered a simulation cell compatible with the atomic distortions that are most common among perovskite oxides, and found a large number of local minima of the energy within 100 meV/f.u. of the ferroelectric ground state. We discuss the variety of low-symmetry structures discovered, as well as the implications of these findings as regards current experimental (e.g., on thin films displaying {\em super-tetragonal} phases) and theoretical (on models for BiFeO3's structural phase transitions) work on this compound.Comment: 14 pages, 9 figures, accepted in PRB (contains small changes in the text with respect to the first version

A System-on-Chip solution for a low power active capsule endoscope with therapeutic capabilities for clip application in the gastrointestinal tract

This paper addresses the circuit implementation challenges resulting from the integration of a therapeutic clip in a magnetically maneuverable wireless capsule intended for colonoscopy. To deal with the size constraints typical of a capsule endoscope, an Application Specific Integrated Circuit (ASIC) has been designed specifically to habilitate the release of the therapeutic clip. The ASIC is a complete System on Chip (SoC) that incorporates a circuit for the low power release of the clip, thus overcoming the limitations of the power supply system. With a size of 14mm2, the ASIC can be incorporated in practically any capsule endoscope, consuming only an idle-state power of 1.5mW

Reflexiones sobre elementos que impactan en la crisis de la codificación del Derecho Internacional.

El presente artículo consiste en una aproximación inicial al tema de la crisis de la codificación internacional. Aborda los factores que han incidido, a juicio de las autoras, en el declive del proceso codificador, en particular la influencia de la fragmentación y el surgimiento de actores no estatales

Reflexiones sobre elementos que impactan en la crisis de la codificación del Derecho Internacional.

El presente artículo consiste en una aproximación inicial al tema de la crisis de la codificación internacional. Aborda los factores que han incidido, a juicio de las autoras, en el declive del proceso codificador, en particular la influencia de la fragmentación y el surgimiento de actores no estatales

Deposition of ITO thin films onto PMMA substrates for waveguide based biosensing devices

Biosensors’ research filed has clearly been changing towards the production of multifunctional and innovative design concepts to address the needs related with sensitivity and selectivity of the devices. More recently, waveguide biosensors, that do not require any label procedure to detect biomolecules adsorbed on its surface, have been pointed out as one of the most promising technologies for the production of biosensing devices with enhanced performance. Moreover the combination of optical and electrochemical measurements through the integration of transparent and conducting oxides in the multilayer structures can greatly enhance the biosensors’ sensitivity. Furthermore, the integration of polymeric substrates may bring powerful advantages in comparison with silicon based ones. The biosensors will have a lower production costs being possible to disposable them after use (“one use sensor chip”). This research work represents a preliminary study about the influence of substrate temperature on the overall properties of ITO thin films deposited by DC magnetron sputtering onto 0,5 mm thick PMMA sheets.NANO/NMED-SD/0076/2007-"NanoMeDiag- Nanobioanalytical platforms for improved medical diagnosis of infections caused by pathogen microorganisms

Phase transition close to room temperature in BiFeO3 thin films

BiFeO3 (BFO) multiferroic oxide has a complex phase diagram that can be mapped by appropriately substrate-induced strain in epitaxial films. By using Raman spectroscopy, we conclusively show that films of the so-called supertetragonal T-BFO phase, stabilized under compressive strain, displays a reversible temperature-induced phase transition at about 100\circ, thus close to room temperature.Comment: accepted in J. Phys.: Condens. Matter (Fast Track Communication

SPADs for vertex tracker detectors in future colliders

Physics aims at the future linear colliders impose such stringent requirements on detector systems that exceed those met by any previous technology. Amongst other novel technologies, SPADs (Single Photon Avalanche Diodes) detectors are being developed to track high energy particles at ILC (International Linear Collider) and CLIC (Compact LInear Collider). These sensors offer outstanding qualities, such as an extraordinary high sensitivity, ultra-fast response time and virtually infinite gain, in addition to compatibility with standard CMOS technologies. As a result, SPAD detectors enable the direct conversion of a single particle event onto a CMOS digital signal in the sub-nanosecond time scale, which leads to the possibility of single BX (bunch crossing) resolution at some particle colliders. However, SPAD detectors suffer from two main problems, namely the noise pulses generated by the sensor and the low fill-factor. The noise pulses worsen the detector occupancy, while the low fill-factor reduces the detection efficiency. This work presents the development of an SPAD pixel detector in standard CMOS technologies as a proof of concept of such devices aimed at the vertex and tracker regions of the future linear colliders. To comply with the specifications imposed by ILC and CLIC, solutions to minimize the intrinsic noise pulses and increase the fill-factor are provided

Seedling emergence and growth of basil varieties under saline conditions

La albahaca presenta variabilidad en la tolerancia al estrés salino y se considera una planta sensible a la salinidad al inicio del crecimiento. El objetivo del estudio fue determinar el efecto del NaCl en la emergencia y crecimiento de albahaca. Se utilizaron veinte variedades sometidas a 0; 50 y 100 mM de NaCl, en un diseño completamente al azar con cuatro repeticiones. Las variables medidas fueron porcentaje y tasa de emergencia, longitud de radícula, altura de plántula, biomasa fresca y seca de radícula y de parte aérea. Los resultados mostraron que la variedad con mayor porcentaje de emergencia fue Thai, mientras que Sweet Genovese y Napoletano exhibieron los menores porcentajes. La variedad Thai mostró la mayor tasa de emergencia y Sweet Genovese la menor. Sweet Dani, Thai, Italian Large Leaf y Red Rubin presentaron mayor longitud de radícula, mientras que Sweet Dani, Italian Large Leaf, Dolly y Emily mostraron mayor biomasa fresca y seca de radícula. Sweet Dani, Licorice, Genovese y Napoletano exhibieron mayor altura de plántula, mientras que Sweet Genovese, Thai y Dolly presentaron mayor biomasa fresca y seca de parte aérea. Se discute la respuesta diferencial de las variedades al NaCl en la emergencia de plántulas.The basil presents variability in the tolerance to salt stress and it is considered a sensitive plant to the salinity at the beginning of the growing period. In this study the effect of NaCl on basil emergence and growth was investigated by subjecting twenty varieties to 3 salinity levels: 0, 50 and 100 mm of NaCl, in a completely randomized design with 4 replications. The variables measured were emergence rate and percentage, radicle length, plantlet height, fresh and dry biomass of radical and of aerial part. Thai showed the greatest emergence percentage while Sweet Genovese and Napoletano exhibited the smallest ones. Thai also showed the highest emergency rate and Sweet Genovese the lowest rate. Sweet Dani, Thai, Italian Large Leaf and Net Rubin presented the maximum radicle length, while Sweet Dani, Italian Large Leaf, Dolly and Emily showed the largest fresh and dry biomass of radicle. Sweet Dani, Licorice, Genovese and Napoletano had the maximun plantlet height, while Sweet Genovese, Thai and Dolly had the largest fresh and dry biomass of aerial part. The different varieties response to NaCl in the plantlets emergency is discussed.Fil: Reyes-Pérez, Juan José. La Paz (Baja California Sur, México). Centro de Investigaciones Biológicas del Noroeste.Fil: Murillo-Amador, Bernardo. La Paz (Baja California Sur, México). Centro de Investigaciones Biológicas del Noroeste.Fil: Nieto-Garibay, Alejandra. La Paz (Baja California Sur, México). Centro de Investigaciones Biológicas del Noroeste.Fil: Troyo-Diéguez, Enrique. La Paz (Baja California Sur, México). Centro de Investigaciones Biológicas del Noroeste.Fil: Reynaldo-Escobar, Inés María. Instituto Nacional de Ciencias Agrícolas (Cuba)Fil: Rueda-Puente, Edgar O.. Universidad de Sonora

Aproximación histórica a la crisis de la codificación del Derecho Internacional

El presente artículo ofrece una aproximación histórica inicial al tema de la crisis de la codificación del derecho internacional. Incluye una periodización realizada por las autoras, donde se esbozan las características de este fenómeno en cada etapa. Así mismo, se aborda el rol jugado por la Comisión de Derecho Internacional (CDI) en el proceso codificador del derecho internacional