Negative Differential Resistance and Steep Switching in Chevron Graphene Nanoribbon Field Effect Transistors

Ballistic quantum transport calculations based on the non-equilbrium Green's function formalism show that field-effect transistor devices made from chevron-type graphene nanoribbons (CGNRs) could exhibit negative differential resistance with peak-to-valley ratios in excess of 4800 at room temperature as well as steep-slope switching with 6 mV/decade subtheshold swing over five orders of magnitude and ON-currents of 88$\mu$A/$\mu$m. This is enabled by the superlattice-like structure of these ribbons that have large periodic unit cells with regions of different effective bandgap, resulting in minibands and gaps in the density of states above the conduction band edge. The CGNR ribbon used in our proposed device has been previously fabricated with bottom-up chemical synthesis techniques and could be incorporated into an experimentally-realizable structure

Las crisis durante el juego : el gol psicológico en el fútbol

The objective of this study is to delve empirically and theoretically into the relationship between an essential situational variable in football scoring a goal in the last stretch of the first period and its consequences in terms of the matchs final score. A theoretical framework was devised and the results of data from two top-level championships the Spanish and Argentine national leagues confirm the existence of this effect. The discussion analyses the importance of the players cognitive interpretation of the situation to explain the phenomenon

Bilateral Hip Arthroplasty: When Is It Safe to Operate the Second Hip? A Systematic Review

Introduction. Patients with degenerative hip disease frequently present with bilateral involvement that requires surgical management. The main goal when treating these patients is to achieve the maximum efficiency without increasing risk of perioperative complications; therefore, the decision regarding the best moment to operate the second hip becomes relevant. Although studies have addressed this topic, whether a simultaneous or staged surgery should be performed remains controversial. The purpose of this study was to determine, based on available evidence, the optimum strategy in terms of safety to operate the second hip in patients with bilateral involvement. Materials and Methods. A meta-analysis was planned. A systematic review of the literature was performed including clinical trials or observational analytical studies comparing the safety of bilateral arthroplasty performed simultaneously or staged by measuring major and minor complications. The appropriateness of a meta-analysis was evaluated through the detailed analysis of the risk of bias and clinical heterogeneity of the included studies. Results. Thirteen studies were selected after the systematic review. A wide variability in the methodological designs was found with a critical risk of bias in most of them. Considerable heterogeneity was detected in defining staged surgery in the cointerventions and how the outcomes were defined and measured. In response to these findings, a meta-analysis was considered not appropriate. The results showed no differences in the risk of mortality or systemic complications in young and healthy patients between simultaneous or staged surgeries. However, increased risk of complications for staged surgeries performed during the same hospitalization was observed. Conclusions. Available evidence is very heterogeneous and the quality of evidence is low. The available evidence supports the performance of simultaneous hip arthroplasty in selected patients (not older than 65 years, ASA 1-2, without cardiovascular comorbidities) and suggests the avoidance of staged surgeries within the same hospitalization

STATISTICAL ANALYSIS AND A CONCEPTUAL CLUSTERING METHOD TO RANK CLIENTS OF A FINANCIAL BANK

En este artículo, se presenta una propuesta de clasificación para la categorización de clientes del banco Tatra Bank (Eslovaquia). En esta propuesta se realiza un análisis estadístico para extraer información útil acerca de los clientes del banco, seguido por una estrategia de clasificación basada en el algoritmo LAMDA (Learning Algorithm for Multivariable Data Analysis). Mediante esta propuesta, los datos de los clientes del banco son pretratados para conformar un archivo de entrenamiento, el cual es usado como entrada en el proceso de aprendizaje. La clasificación de los clientes se desarrolla durante el proceso de reconocimiento. La estrategia planteada tiene dos posibilidades, auto aprendizaje y aprendizaje supervisado

Paz Territorial y Tierras. Una Mirada Crítica Frente a los Acuerdos de la Habana

A review ofMarquartdt, Bernd; Martínez, José y Sánchez, Mariela (eds.) (2018) Paz Territorial y Tierras. Una Mirada Crítica Frente a los Acuerdos de la Habana, Bogotá, Editorial Ibáñez.En reseña deMarquartdt, Bernd; Martínez, José y Sánchez, Mariela (eds.) (2018) Paz Territorial y Tierras. Una Mirada Crítica Frente a los Acuerdos de la Habana, Bogotá, Editorial Ibáñez

European Multidisciplinary and Water-Column Observatory - European Research Infrastructure Consortium (EMSO ERIC): challenges and opportunities for strategic European marine sciences

EMSO (European Multidisciplinary Seafloor and water-column Observatory, www.emso-eu.org) is a large‐scale European Research Infrastructure I. It is a distributed infrastructure of strategically placed, deep‐sea seafloor and water column observatory nodes with the essential scientific objective of real‐time, longterm observation of environmental processes related to the interaction between the geosphere, biosphere, and hydrosphere. The geographic locations of the EMSO observatory nodes represent key sites in European waters, from the Arctic, through the Atlantic and Mediterranean, to the Black Sea (Figure 1), as defined through previous studies performed in FP6 and FP7 EC projects such as ESONET‐CA, ESONET‐NoE, EMSO-PP (Person et al., 2015)Peer Reviewe

Vivir en el Centro Histórico de Bogotá : patrimonio construido y actores urbanos

192 páginas : ilustraciones, fotografías, planos, mapas.El Centro Histórico hasta los años 80 / Amparo de Urbina -- Rasgos físicos-espaciales y usos en el Centro Histórico / Amparo de Urbina y Thierry Lulle -- Las dinámicas poblacionales en la Candelaria / Carlos Augusto Moreno y Thierry Lulle. -- ¿Recuperación del Centro Histórico a pesar del patrimonio? / Amparo de Urbina -- Centro histórico, políticas públicas y dispositivos normativos de protección del patrimonio / Juan Pablo Pinilla y Laura Llinás -- Economía inmobiliaria de la conservación y el deterioro del patrimonio arquitectónico / Oscar Alfredo Alfonso -- Radiografía del habitar. Transformaciones recientes en viviendas de La Candelaria / Luis Alejandro Forero y Amparo de Urbina -- Ciudadanías, territorio e hibridación del patrimonio de uso residencial en el Centro Histórico / Dolly Cristina Palacio.Primera edició