Bulk Fermi surface coexistence with Dirac surface state in Bi2_2Se3_3: a comparison of photoemission and Shubnikov-de Haas measurements

Shubnikov de Haas (SdH) oscillations and Angle Resolved PhotoEmission Spectroscopy (ARPES) are used to probe the Fermi surface of single crystals of Bi2Se3. We find that SdH and ARPES probes quantitatively agree on measurements of the effective mass and bulk band dispersion. In high carrier density samples, the two probes also agree in the exact position of the Fermi level EF, but for lower carrier density samples discrepancies emerge in the position of EF. In particular, SdH reveals a bulk three-dimensional Fermi surface for samples with carrier densities as low as 10^17cm-3. We suggest a simple mechanism to explain these differences and discuss consequences for existing and future transport studies of topological insulators.Comment: 5 mages, 5 figure

3. SISTEMA INTELIGENTE DE CONTROL Y GESTIÓN EN PRÁCTICAS CONTABLES, JURÍDICAS Y TRIBUTARIAS BASADO EN TECNOLOGIAS MÓVILES Y WEB

En la actualidad existen 2,9 millones de personas naturales que declaran en Colombia un nivel de recaudo de 2.32 billones de pesos, la cual requiere un estudio para optimizar los procesos destinados a las áreas tributarias, contables y jurídicas. Por tal motivo se implementa una solución tecnológica que busca ofertar información de calidad, actualizada y certificada por medio de profesionales especializados en la materia. Para ello se presenta un diseño y desarrollo de una solución Tecnológica que contribuya al control y gestión de prácticas contables, agilizar procesos jurídicos y tributarios como el intercambio de información en una comunidad  de expertos. La implementación del proyecto se encuentra distribuida en 4 etapas, análisis, diseño, desarrollo y prueba que permiten validar la hipótesis de la investigación y la puesta en marcha del prototipo en el mercado

Transverse magnetization in Cu/Ni/Cu epitaxial nanorings

The micromagnetic structure in epitaxial (001)-oriented Cu/Ni(14 nm)/Cu rings fabricated by electron beam and focused ion beam lithographies with external diameter of 3 µm and linewidths between 100 and 500 nm is presented. We found that a state with radial orientation of the magnetization prevails at remanence. The evaluation of the magnetoelastic, magnetocrystalline and magnetostatic energies shows that a value as low as 1.5 × 10-3 for the anisotropic relaxation of the in-plane strain components is enough to induce an effective radial easy magnetization direction

3. SISTEMA INTELIGENTE DE CONTROL Y GESTIÓN EN PRÁCTICAS CONTABLES, JURÍDICAS Y TRIBUTARIAS BASADO EN TECNOLOGIAS MÓVILES Y WEB

En la actualidad existen 2,9 millones de personas naturales que declaran en Colombia un nivel de recaudo de 2.32 billones de pesos, la cual requiere un estudio para optimizar los procesos destinados a las áreas tributarias, contables y jurídicas. Por tal motivo se implementa una solución tecnológica que busca ofertar información de calidad, actualizada y certificada por medio de profesionales especializados en la materia. Para ello se presenta un diseño y desarrollo de una solución Tecnológica que contribuya al control y gestión de prácticas contables, agilizar procesos jurídicos y tributarios como el intercambio de información en una comunidad  de expertos. La implementación del proyecto se encuentra distribuida en 4 etapas, análisis, diseño, desarrollo y prueba que permiten validar la hipótesis de la investigación y la puesta en marcha del prototipo en el mercado

Efecto de la asociación patilla (Citrullus lanatus) con maíz (Zea mays) sobre la población y el daño causado por tres insectos plaga y el rendimiento de estos cultivos en la Ciénaga Grande de Lorica, Córdoba.

Maíz-Zea may

Asturiux: detection system of computational anomalies

Everyday in network management, it is complex the process to correlate events in different dimensions: legal violation, intrusions, monitoring failures, violation to security policies or breach of standards; to which face professionals, teaching and students in this area in Colombia. This article presents the technological aspects for the design and development of a distributed system for the computational anomalies detection that was termed “Asturiux”, which arises as a product from a research project in the teleinformatics area. To addressing this problematic it use the network security administration, and anomalies detection. The system was fully developed with free software, in which were integrated different technologies for the communication, authentication, persistence, computational intelligence and remote alerts. The verification instruments and the realized tests, reflect a high level of system efficiency, and acceptation from the actors involved

Insight into the conformational space of n-benzyl-n-(furan-2-ylmethyl) acetamide by NMR spectroscopy and DFT calculations

In this study, the conformational behavior of N-benzyl-N-(furan-2-ylmethyl) acetamide in chloroform was addressed by using a combined experimental/theoretical strategy using NMR spectroscopy and quantum chemical calculations. The 1H and 13C one-dimensional NMR spectra, as well as the two-dimensional HSQC-DEPT and HMBC-DEPT NMR spectra, evinced the presence of a hindered cis(E)-trans(Z) rotational equilibrium in solution. DFT calculations were performed at different theoretical levels using the polarizable continuum model (PCM) and predicted nine (four Z and five E structures) stable conformations. The interconversion dynamics among the different confirmations were established in terms of four different rotational equilibria in CDCl3. The chemical shifts in the 1H and 13C NMR spectra of the compound are similar to the values calculated for the two most abundant conformational equilibria at room temperature, one caused by two Z rotamers and the other by two E rotamers. The compound was also characterized for the first time by FTIR, Raman spectroscopy, and GC/MS spectrometry. Additionally, several acylation methodologies for synthesizing the title compound from N-benzyl-1-(furan-2-yl)methanamine were tested which resulted in high yields (> 90%) under very convenient conditions (10 min, at room temperature).Fil: Corredor Montaña, Jeisson D.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Loaiza, Alix. Pontificia Universidad Javeriana; ColombiaFil: Romanelli, Gustavo Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: de Waele, Isabelle. University Of Lille.; FranciaFil: Tobón Correa, Yeny Alexandra. University Of Lille.; FranciaFil: Gomez Castaño, Jovanny Arles. Universidad Pedagógica y Tecnológica de Colombia; Colombi

Insight into the conformational space of n-benzyl-n-(furan-2-ylmethyl)acetamide by NMR spectroscopy and DFT calculations

In this study, the conformational behavior of N-benzyl-N-(furan-2-ylmethyl) acetamide in chloroform was addressed by using a combined experimental/theoretical strategy using NMR spectroscopy and quantum chemical calculations. The 1H and 13C one‑dimensional NMR spectra, as well as the two-dimensional HSQC-DEPT and HMBC-DEPT NMR spectra, evinced the presence of a hindered cis(E)-trans(Z) rotational equilibrium in solution. DFT calculations were performed at different theoretical levels using the polarizable continuum model (PCM) and predicted nine (four Z and five E structures) stable conformations. The interconversion dynamics among the different confirmations were established in terms of four different rotational equilibria in CDCl3. The chemical shifts in the 1H and 13C NMR spectra of the compound are similar to the values calculated for the two most abundant conformational equilibria at room temperature, one caused by two Z rotamers and the other by two E rotamers. The compound was also characterized for the first time by FTIR, Raman spectroscopy, and GC/MS spectrometry. Additionally, several acylation methodologies for synthesizing the title compound from N-benzyl-1-(furan-2-yl)methanamine were tested which resulted in high yields (> 90%) under very convenient conditions (10 min, at room temperature).Centro de Investigación y Desarrollo en Ciencias Aplicada

Technical and clinical evaluation of a closed loop TIVA system with SEDLineTM spectral density monitoring: Multicentric prospective cohort study

Introduction: Closed loop total intravenous anesthesia is a technique in which the patient’s hemodynamic and anesthetic depth variables are monitored, and based on this information, a computer controls the infusion rate of drugs to keep them within pre-established clinical parameters. Objective: To describe the technical and clinical performance of a closed loop system for total intravenous anesthesia with propofol and remifentanil, using the SEDLineTM monitor Design: Multicentric prospective cohort study Setting: Surgery room Patients: ASA I-II undergoing elective surgery Measurements: The authors designed a closed loop system that implements a control algorithm based on anesthetic depth monitoring and the Patient State Index (PSITM) of the SEDLine monitor for propofol, and on hemodynamic variables for remifentanil. The measurement of clinical performance was made based on the percentage of PSITM maintenance time in the range 20–50. Precision analysis was evaluated by measuring median performance error (MDPE) can be defined as the median difference between actual and desired values, which refers to the degree of precision in which the controller is able to maintain the control variable within the objective set by the anesthesiologist; it represents the direction (over-prediction or underprediction) of performance error (PE) rather than size of errors, which is represented by MDAPE, median absolute percentage error, Wobble index, which is used for measuring the intrasubject variability in performance error. Results: Data were obtained from 93 patients in three healthcare centers. The percentage of PSITM maintenance time in the 20–50 range was 92% (80.7–97.0). MDPE was 10.7 (− 11.0–18.0), MDAPE 21.0 (14.2– 26.8) and wobble 10.7 (7.0–16.9). No adverse surgical or anesthetic events were found