Exact-Diagonalization Studies of Inelastic Light Scattering in Self-Assembled Quantum Dots

We report exact diagonalization studies of inelastic light scattering in few-electron quantum dots under the strong confinement regime characteristic of self-assembled dots. We apply the orthodox (second-order) theory for scattering due to electronic excitations, leaving for the future the consideration of higher-order effects in the formalism (phonons, for example), which seem relevant in the theoretical description of available experiments. Our numerical results stress the dominance of monopole peaks in Raman spectra and the breakdown of selection rules in open-shell dots. The dependence of these spectra on the number of electrons in the dot and the incident photon energy is explicitly shown. Qualitative comparisons are made with recent experimental results.Comment: 11 pages, 11 figure

Analysis of both the envelope sequence and the complete genome of a HIV-1 subtype f cluster of rapid expansion in Galicia: coreceptor use prediction and phylogeny

La epidemia por VIH-1 en España, al igual que en el resto de Europa occidental, está dominada por el subtipo B. Sin embargo, recientemente se ha descrito la rápida expansión de un cluster de subsubtipo F1 entre hombres que tienen relaciones sexuales con hombres en Galicia. Los objetivos de este trabajo son analizar la secuencia de la envoltura de los virus del mencionado cluster para predicción de utilización de correceptores y presencia de aminoácidos característicos, así como caracterizar secuencias de genomas completos, determinando las relaciones filogenéticas con virus de subtipo F de otros países. Los análisis filogenéticos permitieron determinar relaciones del cluster F con virus de Brasil, Suiza, Bélgica, Francia y Gran Bretaña. Por otra parte, se han encontrado posiciones características del cluster en la región V3, diferentes de otras cepas F1, así como en otras regiones de la envoltura. Aparte, se han identificado mutaciones características asociadas a tropismo X4. El cluster de VIH-1 de subtipo F recientemente expandido en Galicia procede de una variante ampliamente diseminada en Europa occidental. Los virus de dicho cluster presentan aminoácidos característicos en la envoltura, identificándose en algunos de ellos mutaciones asociadas a tropismo X4, de potencial relevancia biológicaThe HIV-1 epidemic in Spain, as in the rest of Western Europe, is dominated by subtype B. However, it has recently been reported that a subsubtype F1 cluster has rapidly expanded among men who have sex with men in Galicia. The objectives of this work are to analyze the virus envelope sequence of the aforementioned cluster to predict the use of coreceptors and to examine the presence of characteristic amino acids, as well as to characterize full-length genome sequences, determining the phylogenetic relations with subtype F viruses from other countries. The phylogenetic analyses allowed to determine the relation of the Galician F cluster with viruses from Brazil, Switzerland, Belgium, France and Great Britain. On the other hand, characteristic amino acid residues were found in the V3 loop of viruses of the cluster, differing from other F1 strains, as well as in other regions of the envelope. Additionally, characteristic mutations associated with X4 tropism were identified. The HIV-1 subtype F cluster recently expanded in Galicia derives from a variant widely disseminated in Western Europe. The viruses of the mentioned cluster show characteristic amino acids in the envelope, with mutations associated with X4 tropism having been identified in some of them, which are of potential biological relevance

Oracion funebre en las solemnissimas honras que la Santa Iglesia de Ciudad-Rodrigo consagro a la inmortal memoria de su ... prelado Don Iuan de Andaya y Sotomayor, el dia XVII de Nouiembre, segundo à su entierro, año de 1678

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-2010Port. con orla tip

Coverage-based quality metric of mutation operators for test suite improvement

The choice of mutation operators is a fundamental aspect in mutation testing to guide the tester to an effective test suite. Designing a set of mutation operators is subject to a trade-off between effectiveness and computational cost: a larger mutation population might uncover more faults, but will take longer to analyse. With the aim of resolving this trade-off, several authors have defined an assortment of metrics to determine the most valuable operators. In this work, we extend an existing quality metric by incorporating an additional source of data and coverage information and therefore investigate the extent to which mutants that are often covered but rarely killed can improve the evaluation of mutation operators for the refinement of the test suite. As a case study, we analyse C++ class-level operators based on the new coverage-based quality metric to assess whether the original metric is enhanced. The results when selecting the best-valued operators show that this metric has great potential to help the tester in finding effective mutation operators. In comparison with the metric from which it is derived, the use of coverage data allows to reduce the number of mutants but often loses fewer test cases and, in addition, retains those that seem hard to design

The dependence of oxygen and nitrogen abundances on stellar mass from the CALIFA survey

We analysed the optical spectra of HII regions extracted from a sample of 350 galaxies of the CALIFA survey. We calculated total O/H abundances and, for the first time, N/O ratios using the semi-empirical routine HII-CHI-mistry, which, according to P\'erez-Montero (2014), is consistent with the direct method and reduces the uncertainty in the O/H derivation using [NII] lines owing to the dispersion in the O/H-N/O relation. Then we performed linear fittings to the abundances as a function of the de-projected galactocentric distances. The analysis of the radial distribution both for O/H and N/O in the non-interacting galaxies reveals that both average slopes are negative, but a non-negligible fraction of objects have a flat or even a positive gradient (at least 10\% for O/H and 4\% for N/O). The slopes normalised to the effective radius appear to have a slight dependence on the total stellar mass and the morphological type, as late low-mass objects tend to have flatter slopes. No clear relation is found, however, to explain the presence of inverted gradients in this sample, and there is no dependence between the average slopes and the presence of a bar. The relation between the resulting O/H and N/O linear fittings at the effective radius is much tighter (correlation coefficient $\rho_s$ = 0.80) than between O/H and N/O slopes ($\rho_s$ = 0.39) or for O/H and N/O in the individual \hii\ regions ($\rho_s$ = 0.37). These O/H and N/O values at the effective radius also correlate very tightly (less than 0.03 dex of dispersion) with total luminosity and stellar mass. The relation with other integrated properties, such as star formation rate, colour, or morphology, can be understood only in light of the found relation with mass.Comment: Accepted for publication in A&A. 20 pages, 19 figure

The Low Redshift survey at Calar Alto (LoRCA)

The Baryon Acoustic Oscillation (BAO) feature in the power spectrum of galaxies provides a standard ruler to measure the accelerated expansion of the Universe. To extract all available information about dark energy, it is necessary to measure a standard ruler in the local, z<0.2, universe where dark energy dominates most the energy density of the Universe. Though the volume available in the local universe is limited, it is just big enough to measure accurately the long 100 Mpc/h wave-mode of the BAO. Using cosmological N-body simulations and approximate methods based on Lagrangian perturbation theory, we construct a suite of a thousand light-cones to evaluate the precision at which one can measure the BAO standard ruler in the local universe. We find that using the most massive galaxies on the full sky (34,000 sq. deg.), i.e. a K(2MASS)<14 magnitude-limited sample, one can measure the BAO scale up to a precision of 4\% and 1.2\% using reconstruction). We also find that such a survey would help to detect the dynamics of dark energy.Therefore, we propose a 3-year long observational project, named the Low Redshift survey at Calar Alto (LoRCA), to observe spectroscopically about 200,000 galaxies in the northern sky to contribute to the construction of aforementioned galaxy sample. The suite of light-cones is made available to the public.Comment: 15 pages. Accepted in MNRAS. Please visit our website: http://lorca-survey.ft.uam.es

Linear stability of the Lagrangian triangle solutions for quasihomogeneous potentials

In this paper we study the linear stability of the relative equilibria for homogeneous and quasihomogeneous potentials. Firstly, in the case the potential is a homogeneous function of degree $-a$, we find that any relative equilibrium of the $n$-body problem with $a>2$ is spectrally unstable. We also find a similar condition in the quasihomogeneous case. Then we consider the case of three bodies and we study the stability of the equilateral triangle relative equilibria. In the case of homogeneous potentials we recover the classical result obtained by Routh in a simpler way. In the case of quasihomogeneous potentials we find a generalization of Routh inequality and we show that, for certain values of the masses, the stability of the relative equilibria depends on the size of the configuration.Comment: 21 pages 4 figure

Class mutation operators for C++ object-oriented systems

Mutation testing is a fault injection testing technique around which a great variety of studies and tools for different programming languages have been developed. Nevertheless, the mutation testing research with respect to C++ is pending. This paper proposes a set of class mutation operators related to this language and its particular object-oriented (OO) features. In addition, an implementation technique to apply mutation testing based on the traversal of the abstract syntax tree (AST) is presented. Finally, an experiment is conducted to study the operator behaviour with different C++ programs, suggesting their usefulness in the creation of complete test suites. The analysis includes a Web service (WS) library, one of the domains where this technique can prove useful, considering its challenging testing phase and that C++ is still a reference language for critical distributed systems WS

Voltage controlled sub-THz detection with gated planar asymmetric nanochannels

[EN]This letter reports on room temperature sub-THz detection using self-switching diodes based on an AlGaN/GaN heterostructure on a Si substrate. By means of free-space measurements at 300 GHz, we demonstrate that the responsivity and noise equivalent power (NEP) of sub-THz detectors based on planar asymmetric nanochannels can be improved and voltage controlled by means of a top gate electrode. A simple quasi-static model based on the DC measurements of the current-voltage curves is able to predict the role of the gate bias in its performance. The best values of voltage responsivity and NEP are achieved when the gate bias approaches the threshold voltage, around 600 V/W and 50 pW/Hz1/2, respectively. A good agreement is found between modeled results and those obtained from RF measurements under probes at low frequency (900MHz) and in free-space at 300 GHz