Room temperature ferromagnetic-like behavior in Mn-implanted and post-annealed InAs layers deposited by Molecular Beam Epitaxy

We report on the magnetic and structural properties of Ar and Mn implanted InAs epitaxial films grown on GaAs (100) by Molecular Beam Epitaxy (MBE) and the effect of Rapid Thermal Annealing (RTA) for 30 seconds at 750C. Channeling Particle Induced X- ray Emission (PIXE) experiments reveal that after Mn implantation almost all Mn atoms are subsbtitutional in the In-site of the InAs lattice, like in a diluted magnetic semiconductor (DMS). All of these samples show diamagnetic behavior. But, after RTA treatment the Mn-InAs films exhibit room-temperature magnetism. According to PIXE measurements the Mn atoms are no longer substitutional. When the same set of experiments were performed with As as implantation ion all of the layers present diamagnetism without exception. This indicates that the appearance of room-temperature ferromagnetic-like behavior in the Mn-InAs-RTA layer is not related to lattice disorder produce during implantation, but to a Mn reaction produced after a short thermal treatment. X-ray diffraction patterns (XRD) and Rutherford Back Scattering (RBS) measurements evidence the segregation of an oxygen deficient-MnO2 phase (nominally MnO1.94) in the Mn-InAs-RTA epitaxial layers which might be on the origin of room temperature ferromagnetic-like response observed.Comment: 16 pages, 5 figures. Acepted in J. Appl. Phy

InAs/InP single quantum wire formation and emission at 1.5 microns

Isolated InAs/InP self-assembled quantum wires have been grown using in situ accumulated stress measurements to adjust the optimal InAs thickness. Atomic force microscopy imaging shows highly asymmetric nanostructures with average length exceeding more than ten times their width. High resolution optical investigation of as-grown samples reveals strong photoluminescence from individual quantum wires at 1.5 microns. Additional sharp features are related to monolayer fluctuations of the two dimensional InAs layer present during the early stages of the quantum wire self-assembling process.Comment: 4 pages and 3 figures submitted to Applied Physics Letter

A software-hardware hybrid steering mechanism for clustered microarchitectures

Clustered microarchitectures provide a promising paradigm to solve or alleviate the problems of increasing microprocessor complexity and wire delays. High- performance out-of-order processors rely on hardware-only steering mechanisms to achieve balanced workload distribution among clusters. However, the additional steering logic results in a significant increase on complexity, which actually decreases the benefits of the clustered design. In this paper, we address this complexity issue and present a novel software-hardware hybrid steering mechanism for out-of-order processors. The proposed software- hardware cooperative scheme makes use of the concept of virtual clusters. Instructions are distributed to virtual clusters at compile time using static properties of the program such as data dependences. Then, at runtime, virtual clusters are mapped into physical clusters by considering workload information. Experiments using SPEC CPU2000 benchmarks show that our hybrid approach can achieve almost the same performance as a state-of-the-art hardware-only steering scheme, while requiring low hardware complexity. In addition, the proposed mechanism outperforms state-of-the-art software-only steering mechanisms by 5% and 10% on average for 2-cluster and 4-cluster machines, respectively.Peer ReviewedPostprint (published version

Quaternary glacial evolution in the Central Cantabrian Mountains (Northern Spain)

Peer reviewedPostprin

Reconocimiento y tratamiento precoz del paciente grave. Actuación de enfermería

La parada cardiorrespiratoria (PCR) ocasiona secuelas a corto y largo plazo, ingresos en unidades de cuidados intensivos y/o fallecimientos. El soporte vital inmediato, es decir, la prevención de la parada cardiorrespiratoria trata de adelantarse a dicho acontecimiento poniendo en marcha la cadena de prevención a través de la cual se fomenta la formación del personal sanitario, la monitorización de los signos vitales, el reconocimiento de los signos y síntomas del deterioro fisiológico, la presencia de protocolos de alerta y la respuesta frente a la activación de dichos protocolos. Otra medida que complementa al soporte vital inmediato es la utilización de la aproximación ABCDE (A: Vía aérea; B: Respiración; C: Circulación; D: Discapacidad; E: Exposición). A través de estas medidas se podrá realizar un reconocimiento y tratamiento temprano del deterioro fisiológico de un paciente. El personal de enfermería es primordial para la observación precoz y aplicación de las medidas oportunas. En el presente trabajo se realiza una revisión bibliográfica sobre las distintas causas que pueden originar una parada cardiorrespiratoria, así como una descripción detallada de todos los eslabones que componen la cadena de prevención y sobre las escalas de alerta precoz.Grado en Enfermerí

The Dunford-Pettis property on tensor products

We show that, in some cases, the projective and the injective tensor products of two Banach spaces do not have the Dunford-Pettis property (DPP). As a consequence, we obtain that $(c_0\hat{\otimes}_\pi c_0)^{**}$ fails the DPP. Since $(c_0\hat{\otimes}_\pi c_0)^{*}$ does enjoy it, this provides a new space with the DPP whose dual fails to have it. We also prove that, if $E$ and $F$ are ${\mathscr L}_1$-spaces, then $E\hat{\otimes}_\epsilon F$ has the DPP if and only if both $E$ and $F$ have the Schur property. Other results and examples are given.Comment: 9 page