Radiation in (2+1)-dimensions

In this paper we discuss the radiation equation of state $p=\rho/2$ in (2+1)-dimensions. In (3+1)-dimensions the equation of state $p=\rho/3$ may be used to describe either actual electromagnetic radiation (photons) as well as a gas of massless particles in a thermodynamic equilibrium (for example neutrinos). In this work it is shown that in the framework of (2+1)-dimensional Maxwell electrodynamics the radiation law $p=\rho/2$ takes place only for plane waves, i.e. for $E = B$. Instead of the linear Maxwell electrodynamics, to derive the (2+1)-radiation law for more general cases with $E \neq B$, one has to use a conformally invariant electrodynamics, which is a 2+1-nonlinear electrodynamics with a trace free energy-momentum tensor, and to perform a volumetric spatial average of the corresponding Maxwell stress-energy tensor with its electric and magnetic components at a given instant of time $t$.Comment: 7 pages. Accepted for publication in Phys. Lett.

Ciudadanía, participación, y derechos civiles y políticos de los jóvenes y adolescentes en Iberoamérica

El concepto de ciudadanía-ejercicio de derechos y deberes- es coemergente con el de democracia. No existe democracia sin ciudadanía ni ciudadanía sin democracia. De allí que el análisis de la ciudadanía (estado en el que se encuentran el ejercicio de los derechos y deberes) está obligadamente ligado al análisis de la democracia (características de las normas sobre la toma de decisiones de interés público). La democracia es posible solamente donde existen ciudadanos, es decir, sujetos con iguales derechos y deberes. De la misma manera, el reconocimiento y ejercicio de la ciudadanía solo es posible donde las decisiones de carácter público se las toma según las reglas de la democracia. Históricamente, la ampliación de la ciudadanía a todos los individuos ha resultado en la profundización de la democracia y esta última se ha consolidado como resultado de las luchas por la ampliación de los derechos a todas las personas. Ciudadanía y democracia son dos caras de una misma moneda

Inflation Targeting in Financially Stable Economies: Has it been Flexible Enough?

The events surrounding the financial crisis and recession of 2008-2009 required significant policy responses by central banks. For formal inflation targeters (IT) a natural question arises about whether IT frameworks were flexible enough to address this unprecedented policy environment. In this paper we tackle this question by assessing the policy responses to the crisis of nine IT central banks that did not face systemic problems in their banking or financial systems. We first document substantial deviations of actual policy responses from prescriptions of conventional monetary policy reaction functions, beginning in the second half of 2008. Although several explanations for the deviations are offered, highlighting the extreme challenges at the time, we can more easily reconcile the findings with a decline in the persistence of monetary policy, again, in all cases. Second, we document the banks’ non-monetary-policy measures adopted at the time, and estimate their impact on local money markets (both in local currency and US dollars) and on exchange rates. While these measures helped broadly to normalize markets, firm conclusions on the effectiveness of specific measures are elusive, owing to the difficulty in comparing the different mix of measures adopted across countries and the significant heterogeneity in specific economies’ responses to these non-monetary policy measures.

Integration of Photonic Crystals into Flexible Dye Solar Cells: A Route toward Bendable and Adaptable Optoelectronic Devices Displaying Structural Color and Enhanced Efficiency

Herein is presented what is believed to be the fi rst example of integration of photonic structures in a fl exible optoelectronic device. The resulting devices may be designed to display any color in the visible range and, simultaneously, present enhanced power conversion effi ciency as a consequence of the increased light harvesting caused by the colored back refl ection. The achievement results from the incorporation of nanoparticle-based multilayers with photonic crystal properties that are modifi ed to be compatible with the chemical and physical processing of fl exible nanocrystalline titania electrodes of dye solar cells. The photovoltaic performance of these colored fl exible cells remains unaltered after one hundred bending cycles, thus showing the high-mechanical stability of the ensemble. These devices reunite most characteristics required for building integration or for the construction of solar window panes, such as light weight, stability upon bending, adaptability, and color. This work may trigger promising applications of these highly adaptable and versatile photonic crystals in other fl exible devicesEuropean Union 307081, 622533Ministerio de Economía y Competitividad MAT2014-54852-

Ressenyes

Obra ressenyada: Francisco HERREROS, ¿Por qué confiar? El problema de la creación de capital social. Madrid: Centro de Estudios Avanzados en Ciencias Sociales. Instituto Juan March de Estudios e Investigaciones, 2002

Constitucionalismo aspiracional

Dentro de las principales características que transversalizan los distintos procesos de renovación constitucional que se han realizado en América Latina, fundamentalmente durante las últimas dos décadas, se encuentra el hecho de que se trata de un constitLaw as hope is an idea which embraces one of the mains features of several constitutional renewal processes developed in Latin America in the last two decades. Latin American constitutionalism bring about the conception conforms to law is a system of soc

Apuntes sobre codificación y costumbre en la historia del derecho colombiano

This essay refers to the authoritarianism and to the inefficiency of Colombian and Latin American law. Here it is intended to show that these traits have been maintained in spite of political revolutions and changes in writing and conception of law. The change from a situation in which juridical custom prevailed (in the colonial period) to another one in which code and legislation prevailed (the Republic), did not help in either to lessen or eliminate above mentioned characteristics.Este ensayo se refiere al autoritarismo y a la ineficacia del derecho en Colombia y América Latina. Aquí se intenta mostrar que estos rasgos se han mantenido, no obstante las revoluciones políticas y los cambios en la letra y la concepción del derecho. El paso de una situación en la que predominaba la costumbre jurídica - en la Colonia - a otra en la que predominaba el código y la legislación - la República - no sirvió para atenuar y menos aún para eliminar las características anotadas