On the Origin of the -4.4 eV Band in CdTe(100)"

We calculate the bulk- (infinite system), (100)-bulk-projected- and (100)-Surface-projected Green's functions using the Surface Green's Function Matching method (SGFM) and an empirical tight-binding hamiltonian with tight-binding parameters (TBP) that describe well the bulk band structure of CdTe. In particular, we analyze the band (B--4) arising at --4.4 eV from the top of the valence band at $\Gamma$ according to the results of Niles and H\"ochst and at -4.6 eV according to Gawlik {\it et al.} both obtained by Angle-resolved photoelectron spectroscopy (ARPES). We give the first theoretical description of this band.Comment: 17 pages, Rev-TEX, CIEA-Phys. 02/9

Análisis de los proyectos del sector agropecuario financiados por Colciencias durante el año 2010

Objetivo. Analizar los proyectos del sector agropecuario financiados por Colciencias durante el año 2010. Materiales y métodos. Se utilizó la base de datos de registro de proyectos correspondientes al Programa Nacional de Ciencia, Tecnología e Innovación Agropecuarias para identificar las propuestas presentadas, elegibles y financiadas de las convocatorias del año 2010. Los proyectos se clasificaron con base en la nomenclatura Internacional de la UNESCO para los campos de la ciencia y la tecnología. Se identificó la convocatoria, campos, disciplinas, rama productiva, entidades participantes, departamento de ejecución y montos financiados. Resultados. Durante el año 2010 Colciencias recibió un total de 4.725 propuestas para financiación, de éstas, 790 correspondieron al Programa Nacional de Ciencia, Tecnología e Innovación Agropecuaria. Las disciplinas de los proyectos financiados, fueron en su mayoría pertenecientes al subsector agrícola, seguido por el pecuario y el agroindustrial. Las universidades públicas fueron el tipo de entidad ejecutora al que se le financió un mayor número de proyectos. Los departamentos en los cuales se ejecutó la mayoría de las propuestas financiadas fueron Antioquia, Cundinamarca, Boyacá y Tolima. Conclusiones. El Programa Nacional de Ciencia Tecnología e Innovación Agropecuaria recibió el 16.7% del total de proyectos recibidos por Colciencias en sus convocatorias del año 2010. El mayor número de proyectos recibidos, elegibles y financiables fueron del subsector agrícola y estuvieron presentados y ejecutados por universidades públicas. La inversión total de Colciencias en proyectos del sector agropecuario fue de $32.923.594.000 con un aporte de contrapartida de$33.225.740.000

Vacuum Compatibility of 3D-Printed Materials

The fabrication fidelity and vacuum properties are tested for currently available 3D-printed materials including polyamide, glass, acrylic, and sterling silver. The silver was the only material found to be suitable to ultrahigh vacuum environments due to outgassing and sublimation observed in other materials.Comment: 3 pages, 2 figures, preprin

Authenticity of Formative Assessment Tasks Reported in Research

The current interest in formative assessment practices has led to a permanent innovation of formative assessment tasks. Although the process of rigorously designing and applying assessment tasks is crucial for the success of the formative assessment process, not much attention has been paid to the quality of tasks used within formative assessment practices. One way to judge the quality of assessment tasks is to analyze their authenticity features: realism, complexity, challenge, collaboration, reflection, and diversity. This article uses a narrative review method, retrieving articles from three scientific databases to analyze if tasks reported in formative assessment research practices are authentic. Also, it aims to describe, based on the tasks revised, the best practices to approach each of the authenticity criteria. Furthermore, this paper discusses how the structure of the tasks used (objective or subjective) influences authenticity features. Results indicate that in general, tasks need to be more complex, collaborative, reflective and diversified

Fabry-Perot method for the characterization of integrated optical directional couplers

A method to measure the loss and the power-transfer ratio of directional couplers is presented. It is based on the Fabry-Perot resonances from end-facet reflections. The dependence of the accuracy of the measurements on the facet tilts is described. For low facet misalignments, an uncertainty <0.3 dB in the loss measurements and power-transfer-ratio measurement errors <1% are obtained. For arbitrary facet tilts the errors depend on the extinction ratios. Experimental measurements are reported to verify the method, and its application to multimode interference couplers is shown.Publicad

Efficient state-based CRDTs by delta-mutation

CRDTs are distributed data types that make eventual consistency of a distributed object possible and non ad-hoc. Specifically, state-based CRDTs ensure convergence through disseminating the entire state, that may be large, and merging it to other replicas; whereas operation-based CRDTs disseminate operations (i.e., small states) assuming an exactly-once reliable dissemination layer. We introduce Delta State Conflict-Free Replicated Datatypes (δ-CRDT) that can achieve the best of both worlds: small messages with an incremental nature, disseminated over unreliable communication channels. This is achieved by defining δ-mutators to return a delta-state, typically with a much smaller size than the full state, that is joined to both: local and remote states. We introduce the δ-CRDT framework, and we explain it through establishing a correspondence to current state-based CRDTs. In addition, we present an anti-entropy algorithm that ensures causal consistency, and two δ-CRDT specifications of well-known replicated datatypes.This work is co-financed by the North Portugal Regional Operational Programme (ON.2, O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF), within project NORTE07-0124-FEDER-000058; and by EU FP7 SyncFree project (609551)

SPARC Controls Melanoma Cell Plasticity through Rac1.

Cell transition to a more aggressive mesenchymal-like phenotype is a hallmark of cancer progression that involves different steps and requires tightly regulated cell plasticity. SPARC (Secreted Protein Acidic and Rich in Cysteine) is a matricellular protein that promotes this transition in various malignant cell types, including melanoma cells. We found that suppression of SPARC expression in human melanoma cells compromised cell migration, adhesion, cytoskeleton structure, and cell size. These changes involved the Akt/mTOR pathway. Re-expression of SPARC or protein addition restored all the cell features. Suppression of SPARC expression was associated with increased Rac1-GTP levels and its membrane localization. Expression of the dominant negative mutant of Rac1 counteracted almost all the changes observed in SPARC-deficient cells. Overall, these data suggest that most of the SPARC-mediated effects occurred mainly through the blockade of Rac1 activity.Fil: Salvatierra Colussi, Edgardo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Alvarez, Mariano J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Leishman, Claudia C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Rivas Baquero, Elvia Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Lutzky, Viviana P.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; Argentina. The Royal Brisbane Hospital; AustraliaFil: Chuluyan, Hector Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Podhajcer, Osvaldo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentin

Performance of the modified Becke-Johnson potential

Very recently, in the 2011 version of the Wien2K code, the long standing shortcome of the codes based on Density Functional Theory, namely, its impossibility to account for the experimental band gap value of semiconductors, was overcome. The novelty is the introduction of a new exchange and correlation potential, the modified Becke-Johnson potential (mBJLDA). In this paper, we report our detailed analysis of this recent work. We calculated using this code, the band structure of forty one semiconductors and found an important improvement in the overall agreement with experiment as Tran and Blaha [{\em Phys. Rev. Lett.} 102, 226401 (2009)] did before for a more reduced set of semiconductors. We find, nevertheless, within this enhanced set, that the deviation from the experimental gap value can reach even much more than 20%, in some cases. Furthermore, since there is no exchange and correlation energy term from which the mBJLDA potential can be deduced, a direct optimization procedure to get the lattice parameter in a consistent way is not possible as in the usual theory. These authors suggest that a LDA or a GGA optimization procedure is used previous to a band structure calculation and the resulting lattice parameter introduced into the 2011 code. This choice is important since small percentage differences in the lattice parameter can give rise to quite higher percentage deviations from experiment in the predicted band gap value.Comment: 10 pages, 2 figures, 5 Table