On the stability of the primordial closed string gas

We recast the study of a closed string gas in a toroidal container in the physical situation in which the single string density of states is independent of the volume because energy density is very high. This includes the gas for the well known Brandenberger-Vafa cosmological scenario. We describe the gas in the grandcanonical and microcanonical ensembles. In the microcanonical description, we find a result that clearly confronts the Brandenberger-Vafa calculation to get the specific heat of the system. The important point is that we use the same approach to the problem but a different regularization. By the way, we show that, in the complex temperature formalism, at the Hagedorn singularity, the analytic structure obtained from the so-called F-representation of the free energy coincides with the one computed using the S-representation.Comment: 20 pages and 1 figure. The final version that appeared in JHE

Cómo definir los nombres de instrumentos musicales. Propuesta lexicográfica

Este trabajo se enmarca en dos proyectos de investigación (FFI2009-10817 y FFI2009-12191), financiados por el Ministerio de Ciencia e Innovación

Caracterización lingüística de los nombres de instrumentos de medida. Repercusiones lexicográficas

Este artículo ha sido parcialmente financiado a través de sendas ayudas del Ministerio de Ciencia e Innovación concedidas a los proyectos FFI-2009-10817 y FFI-2009-1219

Mass media ethics vs. ethnicity : the Cuban American National Foundation\u27s battle with the Miami Herald

In 1992, a prominent Cuban-American organization, the Cuban American National Foundation, launched a full-scale campaign against the Miami Herald following an editorial against the Cuban Democracy Act, sponsored by Congressman Robert Torricelli, (D-NJ). The bill, which the Foundation endorsed and helped craft, was aimed at tightening the loopholes on the U.S. embargo against Cuba. Two men-CANF Chairman Jorge Mas Canosa and Herald publisher David Lawrence-represented opposing sides of the feud. CANF galvanized the exile community to support its side of the debate. The Herald used its opinion and editorial pages to argue against Mas\u27s charges that the newspaper attacked the values and culture of the Cuban-American people. The opposing sides symbolized two distinct paradigms of culture and politics that were vying for control over setting the agenda in Miami\u27s public opinion sphere. The battle between a powerful Cuban exile organization and Miami\u27s daily newspaper is a defining moment for journalism in the twenty-first century. It also serves as a cautionary tale for daily newspapers in highly multicultural and heavily populated metropolitan areas of the nation still struggling to meet the needs of their audiences while adhering to the tenets of American journalism. A historical analysis sets the groundwork for future qualitative and quantitative analyses

Internet en la clase de lengua y literatura. Usos y estrategias didácticas

Los avances tecnológicos han transformado las sociedades actuales y han repercutido de manera muy intensa en todos los aspectos de nuestras vidas. El proceso de enseñanza-aprendizaje también ha participado de estos cambios, de manera que profesor y alumno se han visto embarcados en una aventura cuyo objetivo más inmediato es mejorar y perfeccionar las formas de acceder al conocimiento. Sin duda Internet es uno de los recursos que permite una mayor explotación didáctica; por eso conviene conocer muy bien los pormenores de su utilización en el aula.The technological progress has transformed the society today and has had a very strong impact on all aspects of our lives. The teaching-learning process has also been involved in these changes so teachers and students take part in an adventure whose immediate objective is to improve and refine the ways of accesing knowledge. Undoubtedly the Internet is one of the resources that enables greater didactic exploitation. Therefore it is advisable to know well the details of its use in the classroom

Thermodynamic nonextensivity in a closed string gas

Well known results in string thermodynamics show that there is always a negative specific heat phase in the microcanonical description of a gas of closed free strings whenever there are no winding modes present. We will carefully compute the number of strings in the gas to show how this negative specific heat is related to the fact that the system does not have thermodynamic extensivity. We will also discuss the consequences for a system of having a microcanonical negative specific heat versus the exact result that such a thing cannot happen in any canonical (fixed temperature) description.Comment: Title + 13 pages, more typos correcte

High Frequency Electrical Transport Properties of Carbon Nanotubes

Carbon nanotubes (CNTs) have extraordinary electronic properties owing to the unique band structure of graphene and their one-dimensional nature. Their small size and correspondingly small capacitances make them candidates for novel high-frequency devices with cut-off frequencies approaching one terahertz, but their high individual impedance hampers measurements of their high-frequency transport properties. In this dissertation, I describe the fabrication of carbon nanotube Schottky diodes on high-frequency compatible substrates and the measurement of their rectification at frequencies up to 40GHz as a method of examining the high-frequency transport of individual CNTs despite their high impedance. The frequency dependence of the rectified signal is then used to extract the Schottky junction capacitance as a function of applied bias and ambient doping and to look for resonances which might be a signature of a room-temperature Luttinger Liquid