Screening of the quantum-confined Stark effect in AlN/GaN nanowire superlattices by Germanium doping

We report on electrostatic screening of polarization-induced internal electric fields in AlN/GaN nanowire heterostructures with Germanium-doped GaN nanodiscs embedded between AlN barriers. The incorporation of Germanium at concentrations above $10^{20}\,\text{cm}^{-3}$ shifts the photoluminescence emission energy of GaN nanodiscs to higher energies accompanied by a decrease of the photoluminescence decay time. At the same time, the thickness-dependent shift in emission energy is significantly reduced. In spite of the high donor concentration a degradation of the photoluminescence properties is not observed.Comment: Manuscript including Supplemental material (15 pages, 5 figures

Comparison of diagenetic and low-grade metamorphic evolution of chlorite in associated metapelites and metabasites: an integrated TEM and XRD study

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73635/1/j.1525-1314.2000.00272.x.pd

Effects of imperfections for Shor's factorization algorithm

We study effects of imperfections induced by residual couplings between qubits on the accuracy of Shor's algorithm using numerical simulations of realistic quantum computations with up to 30 qubits. The factoring of numbers up to N=943 show that the width of peaks, which frequencies allow to determine the factors, grow exponentially with the number of qubits. However, the algorithm remains operational up to a critical coupling strength $\epsilon_c$ which drops only polynomially with $\log_2 N$. The numerical dependence of $\epsilon_c$ on $\log_2 N$ is explained by analytical estimates that allows to obtain the scaling for functionality of Shor's algorithm on realistic quantum computers with a large number of qubits.Comment: 10 pages, 10 figures, 1 table. Added references and new data. Erratum added as appendix. 1 Figure and 1 Table added. Research is available at http://www.quantware.ups-tlse.fr

General amino acid control in fission yeast is regulated by a nonconserved transcription factor, with functions analogous to Gcn4/Atf4

Eukaryotes respond to amino acid starvation by enhancing the translation of mRNAs encoding b-ZIP family transcription factors (GCN4 in Saccharomyces cerevisiae and ATF4 in mammals), which launch transcriptional programs to counter this stress. This pathway involves phosphorylation of the eIF2 translation factor by Gcn2-protein kinases and is regulated by upstream ORFs (uORFs) in the GCN4/ATF4 5′ leaders. Here, we present evidence that the transcription factors that mediate this response are not evolutionarily conserved. Although cells of the fission yeast Schizosaccharomyces pombe respond transcriptionally to amino acid starvation, they lack clear Gcn4 and Atf4 orthologs. We used ribosome profiling to identify mediators of this response in S. pombe, looking for transcription factors that behave like GCN4. We discovered a transcription factor (Fil1) translationally induced by amino acid starvation in a 5′ leader and Gcn2-dependent manner. Like Gcn4, Fil1 is required for the transcriptional response to amino acid starvation, and Gcn4 and Fil1 regulate similar genes. Despite their similarities in regulation, function, and targets, Fil1 and Gcn4 belong to different transcription factor families (GATA and b-ZIP, respectively). Thus, the same functions are performed by nonorthologous proteins under similar regulation. These results highlight the plasticity of transcriptional networks, which maintain conserved principles with nonconserved regulators

Mathematical Models for Estimating the Risk of vCJD Transmission

We present two different simple models for vCJD transmission by blood transfusion. Both models indicate that transfusions alone are unlikely to cause more than a few infections, unless the number of primary cases increases. To improve our models, future work should pursue data collection, empirical estimation of the model parameters, and examination of the underlying assumptions of our frameworks. Further improvements could also include examining susceptibility to vCJD infection by age group and iatrogenic infections introduced through surgical instruments. Regarding the latter, it may be worthwhile to conduct experiments to quantify the transmission of prions from an infected surgical instrument after repeated sterilization procedures

Comparación de Resultados del electromiograma y de la saculorradiculografía en el Diagnóstico de las Hernias Discales

Los autores presentan un estudio comparativo de E.M.G. y Saculorradiculografía en relación con los hallazgos quirúrgicos de 100 Hernias Discales intervenidas. Para el E.M.G. se ha conseguido una exactitud global del 83% y para la saculorradiculografía del 79%. La saculorradiculografía ha demostrado mayor exactitud para la raiz S1 que paral a L5 (85,7% frente a 70,4%) y el E.M.G. mayor para la L5 que para la S1 (88,6% frente a 78,5%). El E.M.G. tiene una especial utilidad para el diagnóstico y despistaje de neuropatías y para la comprobación de recuperación post-quirúrgica de lesiones sin axonotmesis. La exactitud de los resultados en el E.M.G. están en relación directa con la habilidad del examinador a la hora de conseguir e interpretar los resultados.The authors made a comparative study between the Electromyography (EMG) and the radiculography with the surgical findings in 100 Herniated intervertebral disk (H.I.D.) operated on. With the E.M.G. they had obtained a correct diagnostic in 83% of case s and 79% with the radiculography. The radiculography showed the bigger accurancy in S1 than L5 (85'7% - 70'4%) and E.M.G. showed bigger accurancy B in L5 than S1 (88'6% - 78'5%). The E.M.G. had an special utility in the diagnosis of neuropathie s and the review and follow up after surgical procedure. It's very important the trainning of the E.M.G. examine r to obtain correct information

Química mineral de encraves ultramáficos nas lavas da erupção de 2014 na Ilha do Fogo (Cabo Verde) : resultados preliminares

Resumo alargad