Nanotransistors quàntics

La nanoelectrònica dóna la benvinguda als transistors. Aviat es podrà treballar amb freqüències de Terahertzs (1012 operacions per segon). Per aconseguir aquest objectiu, l'estudi del seu corrent no només es mesurarà mitjançant el corrent de conducció, sinó també mitjançant el corrent de desplaçament. Un sistema complex donada la quantitat d'electrons amb què es treballa i que l'article següent resol amb un model numèric que calcula el corrent total, és a dir, conducció més desplaçament. Basada en el càlcul quàntic, aquesta proposta numèrica facilitarà l'entrada triomfant dels nanotransistors que, sembla ser, podran oferir una electrònica més barata i petita amb múltiples aplicacions.La nanoelectrónica da la bienvenida a los transistores. En breve se podrá trabajar con frecuencias de Terahertzs (1012 operaciones por segundo). Para conseguir este objetivo, el estudio de su corriente no solamente se medirá mediante la corriente de conducción, sino también mediante la corriente de desplazamiento. Un sistema complejo dada la cantidad de electrones con que se trabaja, y que el siguiente artículo resuelve con un modelo numérico que calcula la corriente total, es decir, conducción más desplazamiento. Basada en el cálculo cuántico, esta propuesta numérica facilitará la entrada triunfante de los nanotransistores que, parece ser, podrán ofrecer una electrónica más barata y pequeña con múltiples aplicaciones

Resonant Solutions and Turning Points in an Elliptic Problem with Oscillatory Boundary Conditions

We consider the elliptic equation -Δu + u = 0 with nonlinear boundary conditions ∂u/∂n = λu + g(λ,x,u), where the nonlinear term g is oscillatory and satisfies g(λ,x,s)/s→0 as |s|→0. We provide sufficient conditions on g for the existence of sequences of resonant solutions and turning points accumulating to zero

Infinitely Many Stability Switches in a Problem with Sublinear Oscillatory Boundary Conditions

We consider the elliptic equation −u+u = 0 with nonlinear boundary condition ∂u ∂n = λu + g(λ, x, u), where g(λ,x,s) s → 0, as |s|→∞ and g is oscillatory. We provide sufficient conditions on g for the existence of unbounded sequences of stable solutions, unstable solutions, and turning points, even in the absence of resonant solutions

A Demand-Side Theory of Labor Informality: Workers\u27 Trust and States\u27 Credible Commitment

Labor informality is a vexing issue across Latin America, with negative implications for policy areas from economic growth to social safety nets. Despite decades of efforts by national governments and international organizations, informality levels remain stubbornly high across the region. Insights from the extant literature suggest informality arises because creating formal sector jobs is too costly or the costs of formality for workers are too high. In contrast to most previous works on informality, this project steps back from standard materialistic assumptions and aims to uncover how the overall relationship between states and citizens impacts workers\u27 incentives to work formally. This work posits workers\u27 resistance to formality, despite the stability and protections it promises, derives from a lack of trust and long-standing view that the state has repeatedly failed to provide credible and reliable benefits/services or improvements in their living standards. The empirical results from this dissertation support the contention. At the country level, across Latin American countries, aspects affecting the nature and quality of the state\u27s relationship with citizens relate to higher levels of labor informality. In addition, these factors, particularly corruption, condition the effectiveness of mainstream labor reform policies – labor market flexibilization and businesses regulations– to reduce informality levels. Furthermore, primary and secondary data at the individual level in the Colombian context suggest first, individuals feel comfortable with the conditions of informality and choose informality voluntarily. And second, there is an empirical link between trust in the state and an individuals’ decision to demand an informal job over a comparable formal job alternative. All in all, this dissertation suggests putting the state and the quality of the relationship with its citizens as a central analytical element to understand the issue of informality is essential

Two new species of Golofa Hope, 1837 (Coleoptera : Melolonthidae : Dynastinae) from the colombian andes, south America.

Objetivo: Realizar la descripción de dos nuevas especies del género Golofa. Alcance: Ampliar el listado de especies de la tribu Dynastini para Colombia. Metodología: Se revisaron los especímenes del género Golofa depositados en la Colección Familia PardoLocarno CFPL-COL, estableciéndose diferencias entre las especies ya identificadas y los ejemplares tipo usados para la descripción de las dos nuevas especies que se revisan en el presente manuscrito. Principales resultados: Se describen dos nuevas especie de Golofa Hope, 1837, presentándose registros fotográficos con valor diagnóstico. Se amplía a nueve el número de especies para Colombia, quedando la sinopsis de especies conformada así: Golofa aegeon Drury, 1773, Golofa antiqua Arrow, 1911, Golofa claviger Linnaeus, 1771, Golofa eacus Burmeister, 1847, Golofa paradoxa Dechambre, 1975, Golofa pelagon Burmeister, 1847, Golofa porteri Hope, 1837, Golofa farallonensis n. sp. Pardo-Locarno & Villalobos-Moreno y Golofa veliae n. sp. Pardo-Locarno & Villalobos-Moreno. Conclusiones: Estos registros ratifican la distribución tropandina del grupo, evidenciándose el poco conocimiento biológico y biogeográfico de este grupo en Colombia. Los resultados indican una gran diversidad del género en el país. Se recomienda ampliar el estudio de la distribución de las especies mencionadas.Objective: To describe two new species of the genus Golofa. Scope: To expand the list of species of the tribe Dynastini for Colombia. Methodology: We reviewed the specimens of the genus Golofa deposited in the Colección Familia Pardo-Locarno CFPL-COL, establishing differences between the species already identified and the specimens type used for the description of the two new species reviewed in this manuscript. Main results: We described two new species of Golofa Hope, 1837, showing photographic records with diagnostic value. The number of species for Colombia is increased to nine, thus, the synopsis of species is formed as follows: Golofa aegeon Drury, 1773, Golofa antiqua Arrow, 1911, Golofa claviger Linnaeus, 1771, Golofa eacus Burmeister, 1847, Golofa paradoxa Dechambre, 1975, Golofa pelagon Burmeister, 1847, Golofa porteri Hope, 1837, Golofa farallonensis n. sp. Pardo-Locarno & Villalobos-Moreno y Golofa veliae n. sp. Pardo-Locarno & Villalobos-Moreno. Conclusions: These records ratify the Tropandean distribution of the group, evidencing the little biological and biogeographic knowledge of this group in Colombia. The results indicate a great diversity of the genus in the country, so that, the study of species distribution is recommended

High-J v=0 SiS Maser Emission in IRC+10216: A New Case of Infrared Overlaps

We report on the first detection of maser emission in the J=11-10, J=14-13 and J=15-14 transitions of the v=0 vibrational state of SiS toward the C-rich star IRC+10216. These masers seem to be produced in the very inhomogeneous region between the star and the inner dust formation zone, placed at 5-7 R*, with expansion velocities below 10 km/s. We interpret the pumping mechanism as due to overlaps between v=1-0 ro-vibrational lines of SiS and mid-IR lines of C2H2, HCN and their 13C isotopologues. The large number of overlaps found suggests the existence of strong masers for high-J v=0 and v=1 SiS transitions, located in the submillimeter range. In addition, it could be possible to find several rotational lines of the SiS isotopologues displaying maser emission.Comment: 4 pages, 1 figure, published in the ApJ Letter

Development and urban sustainability: An analysis of efficiency using data envelopment analysis

In recent decades, the majority of cities in developing countries have grown rapidly and have experienced increasing environmental problems. These changes have generated a broad discussion on urban sustainability and development. In this discussion, it is fundamental to establish methods for measuring urban sustainability using a quantitative approach. This research seeks to estimate and evaluate the environmental, social, and economic efficiency of cities in a developing country, Colombia, using data envelopment analysis to determine the changes that occurred between 2005 and 2013. In this study, indicators related to economic, environmental, and social performance are used with the objective of analyzing efficiency from urban sustainability. The results indicate differences among cities, where the efficient cities show adequate resource use, lower environmental impacts, improved social conditions, and guaranteed economic growth and development. Moreover, as the city scale increases, urban sustainability declines. All these findings are important in the formulation and design of adequate urban policies to improve and strengthen sustainability and social welfare over the long term, particularly in cities in developing countries. © 2016 by the authors