Mapping the Americanization of English in Space and Time

As global political preeminence gradually shifted from the United Kingdom to the United States, so did the capacity to culturally influence the rest of the world. In this work, we analyze how the world-wide varieties of written English are evolving. We study both the spatial and temporal variations of vocabulary and spelling of English using a large corpus of geolocated tweets and the Google Books datasets corresponding to books published in the US and the UK. The advantage of our approach is that we can address both standard written language (Google Books) and the more colloquial forms of microblogging messages (Twitter). We find that American English is the dominant form of English outside the UK and that its influence is felt even within the UK borders. Finally, we analyze how this trend has evolved over time and the impact that some cultural events have had in shaping it.Comment: 16 pages, 6 figures, 2 tables. Published versio

Optimal streaks in a Falkner-Skan boundary layer

This paper deals with the optimal streaky perturbations (which maximize the perturbed energy growth) in a wedge flow boundary layer. These three dimensional perturbations are governed by a system of linearized boundary layer equations around the Falkner-Skan base flow. Based on an asymptotic analysis of this system near the free stream and the leading edge singularity, we show that for acute wedge semi-angle, all solutions converge after a streamwise transient to a single streamwise-growing solution of the linearized equations, whose initial condition near the leading edge is given by an eigenvalue problem first formulated in this context by Tumin (2001). Such a solution may be regarded as a streamwise evolving most unstable streaky mode, in analogy with the usual eigenmodes in strictly parallel flows, and shows an approximate self-similarity, which was partially known and is completed in this paper. An important consequence of this result is that the optimization procedure based on the adjoint equations heretofore used to define optimal streaks is not necessary. Instead, a simple low-dimensional optimization process is proposed and used to obtain optimal streaks. Comparison with previous results by Tumin and Ashpis (2003) shows an excellent agreement. The unstable streaky mode exhibits transient growth if the wedge semi-angle is smaller than a critical value that is slightly larger than $\pi/6$, and decays otherwise. Thus the cases of right and obtuse wedge semi-angles exhibit less practical interest, but they show a qualitatively different behavior, which is briefly described to complete the analysis

PRINCIPIO DEMOCRÁTICO Y DERECHO A DECIDIR

En aquestes pàgines es tracta de reflexionar sobre la connexió, a primera vista evident, entre el principi democràtic i el dret a decidir. Tanmateix, es posen de manifest algunes de les contradiccions en què cauen alguns dels seus valedors i es defensa, al contrari, la necessitat d’establir que la relació entre el principi de l’Estat de dret i el principi democràtic no pot ser de preeminència de cap d’ells sobre l’altre. La raó es troba en el fet que no es pot entendre el principi democràtic com la mera suma de les voluntats particulars d’una determinada col·lectivitat, sinó com a expressió de les condicions que asseguren la conformació d’una voluntat política racional. El principi democràtic només es pot comprendre així des d’una concepció normativa i no fàctica del poder sobirà.En estas páginas se trata de reflexionar sobre la conexión, a primera vista evidente, entre el principio democrático y el derecho a decidir. Sin embargo, se ponen de manifiesto algunas de las contradicciones en las que caen algunos de sus valedores y se defiende, por el contrario, la necesidad de establecer que la relación entre el principio del Estado de derecho y el principio democrático no puede serlo de preeminencia de ninguno de ellos sobre el otro. La razón se encuentra en que no cabe entender el principio democrático como la mera suma de las voluntades particulares de una determinada colectividad, sino como expresión de las condiciones que aseguran la conformación de una voluntad política racional. El principio democrático sólo puede comprenderse así desde una concepción normativa y no fáctica del poder soberano.This article aims at reflecting upon the connection, evident at first sight, between the democratic principle and the right to decide. However, the article highlights some of the contradictions in which some supporters of such connection fall, and defends that the relationship between the principle of the rule of law and the democratic principle cannot give either preeminence over the other. The reason lies in the idea that the democratic principle cannot be understood as the mere sum of particular wills from a specific community, but rather as an expression of the conditions that ensure the formation of a rationally political will. The democratic principle can only be understood from a normative, and not factual, conception of sovereign power

The Sustainable Management of Metals: An Analysis of Global Research

The objective of this study was to analyze research trends in the field of sustainable management of metals on a global level between 1993 and 2017. To do so, a bibliometric analysis was carried out on a total of 6967 articles. The results revealed the growing interest in this research field, particularly over the last five year-period during which 63% of all articles were published. The three journals in which most articles had been published were the Journal of Cleaner Production, ACS Sustainable Chemistry and Engineering, and Chemsuschem. The countries that published the most articles were China, the United States, India, Germany, and the United Kingdom. A sizeable network of collaboration has been established between countries for the joint publication of studies. The main lines of research have been focused on metal decontamination in water and soil, waste management oriented towards reuse and recycling, and the innovation of processes for cleaner and more efficient production. The results revealed the need for comprehensive studies that integrate different disciplines within the same analytical framework, and to promote research that contributes to the different dimensions of sustainability (environmental, economic, and social)

Naturaleza de ciertas manchas que aparecen en tejidos de lana

La presencia de ciertas manchas que aparecen en determinados artículos de lana, es motivada por la existencia de fibras coloreadas en el vellón del cordero, las cuales no se encuentran localizadas en determinadas zonas del vellón. La coloración de las fibras se produce tanto por causas de tipo exógeno como por causas endógenas. Al proceder a la identificación del origen de la coloración según las reacciones propuestas por Seddon, se ha encontrado la presencia de cobre en las fibras verdes y ligeras trazas de hierro en las rojas, no habiéndose podido determinar el origen de las fibras azules. La coloración de las fibras, sólo ha podido ser eliminada de forma permanente, mediante tratamiento con soluciones oxidantes de composición similar a las empleadas en el blanqueo de la lana.Peer Reviewe

Naturaleza de ciertas manchas que aparecen en tejidos de lana

En el curso de este trabajo, se inicia el estudio sobre la naturaleza de determinadas manchas que aparecen en artículos de lanería de señora, fabricados con mezcla de puncha y lana. Se determina cual de las materias que intervienen, es el origen de la aparición de las manchas, así como las características más sobresalientes de las fibras que las motivan. Finalmente se efectúa el primer paso en la investigación del origen y naturaleza de las mismas.Peer Reviewe

Multi-Sensor System For Level Measurements With Optical Fibres

A system for measuring liquid level in multiple tanks using optical fibre technology has been developed. The oil field service industry can benefit from this intrinsically safe technology. Plastic optical fibre (POF) sensor heads are excited by a 650 nm laser. Laser diodes are housed in ST connectors to obtain compact and rough prototypes and these connectors are also used in the fibre pigtails. Optical multiplexing is used to increase the measuring safety area. POF splitters and connectors are used to combine all the receiving sensor head fibres in a single one. Frequency division multiplexing is used to address each sensor head. The global system is controlled through a user friendly software application running in a PC connected to the system via an RS-232 port. A scalable prototype with a range greater than 2 meter, good linearity, better than 1.5% FS (full scale), high accuracy and resolution is developed using a unique lens to collimate and focus the light. Measurements are taken to validate the designs. Up to 8 sensor heads can be connected in the present implementation. But a greater number of sensors can be allocated with minor modifications in the electronics.Universidad Carlos III de MadridPublicad