Las matemáticas de lo secreto

En un mundo en que el que cada vez más los medios de comunicación son electrónicos, la seguridad de las transacciones electrónicas nos afecta a todos. La criptografía, la seguridad de la información en general, actualmente está basada en métodos matemáticos, son un campo de nuestra vida cotidiana en el que el aporte de las matemáticas es esencial. En este artículo se muestran algunos sistemas de cifrado artesanales de la criptografía clásica y se introducen los algoritmos de cifrado, de autentificación de documentos y firma digital hoy en día más utilizados: los RSA, que están basados en un resultado clásico de la teoría de números. El estilo del artículo es narrativo, todos los métodos se explican con ejemplos, con comentarios históricos. Su contenido se puede utilizar para diseñar un “taller de matemáticas” dirigido a estudiantes de nivel preuniversitario

El «extraño mal» de Teresa Wilms Montt. Romanticismo y transgresión de la normativa de género en la vanguardia chilena

El presente trabajo trata de explicar la naturaleza y el origen de uno de los sintagmas más recurrentes en la obra de Teresa Wilms Montt, el «extraño mal», que aparece tanto en sus Diarios, publicados en un volumen recopilatorio en 1994 por Ruth González Vergara, como en la obra literaria Inquietudes sentimentales de 1917. La investigación parte de la búsqueda de un aparato crítico que sustente el análisis del «extraño mal» como paradigma de su producción intimista que une vida, diarios y obra. Dicho sentimiento refleja la interacción de los factores históricos, psicológicos y sociales en su obra. Como veremos, el «extraño mal» no solo refleja la indiscutible ligazón entre la vida y la obra de la autora que nos concierne, sino que, plasma, asimismo, la unión entre los dos temas más tratados por ella: el amor y la muerte. Empezaremos con un ineludible, pero breve, apartado biográfico y una contextualización social y cultural que nos permita comprender mejor la situación de opresión en la que Teresa escribe, como mujer en la sociedad chilena de finales del siglo XIX y principios del XX. A pesar de que la paulatina modernización del país dará una lenta cabida a la mujer en el terreno público, esta será con desconfianza y represalias, lo cual se ve reflejado en el caso de Teresa. A continuación explicaremos la interrelación entre vida, diarios y obra, además del romanticismo transmitido en todas ellas, ya que fue precisamente esta personalidad romántica la que causó el choque con la sociedad y unas ansias de libertad e ideales superiores, cuya imposibilidad de realización crearon un núcleo melancólico que generó el «extraño mal», expresado primero en forma de enfermedad del amor por la incapacidad de encontrar relaciones sentimentales plenas; y, después, en forma de spleen, tedio, hastío, a causa de la Nada a la que se vio abocada por la frustración de todos sus intentos de encontrar amor y una realidad ideal más allá del mundo conocido

Metamaterials for radiactive cooling

The increasing pressure of society to decrease energy consumption and to enhance energetic efficiency has lead to search novel technologies to accomplish it. Notwithstanding the increasing electricity production of renewable energies, it is a fact that the energy expenses can be drastically reduced in most areas. Among these areas, cooling systems stand out for being energetically inefficient. Furthermore, both economical and energy cost of such systems are increasing due to the global warming, which is aggravated by the energy production for them, making a loop that is increasingly damaging the environment. A solution to this problem has emerged under the name of radiative cooling, which is a physical phenomenon by which any terrestrial object losses heat in form of radiation that is sent to outer space. This process can be explained by black body radiation theory and the atmospheric window. The former states that any object at some temperature above 0 K radiates energy at all wavelengths, with its radiation peak and spectral location modulated by its temperature. The latter is a frequency band in which the atmosphere is transparent to radiation, making possible for waves at certain frequencies to cross freely. These phenomena allows a direct heat transmission between earth and space, which is cold and almost infinite, making a great storage for excess warmth without wasting energy in the process. In this work, it has been studied one of the main technologies that can implement radiative cooling in practice, metamaterials, with the aim to understand how to improve its associated problems of manufacturing and design for radiative cooling applications. In Chapter 1, the fundamentals of radiative cooling are introduced along with the state of the art. Then, Chapter 2 presents the materials used in the literature and in this work to develop later analytical models for thin film multilayered metamaterials and a possible way to automatically design them. To better understand the analytical developments, two appendices introducing the underlying theory and equations are included. Also, the software used in this work is presented. Finally, the performance and analysis of three different radiative cooling devices is exposed in Chapter 3, one of them using the materials and methods of Chapter 2.Máster Universitario en Ingeniería de Telecomunicación por la Universidad Pública de NavarraNafarroako Unibertsitate Publikoko Unibertsitate Masterra Telekomunikazio Ingeniaritza

Consulting citizens: technologies of elicitation and the mobility of publics

The new centrality of “the public” to the governance of science and technology has been accompanied by a widespread use of public consultation mechanisms designed to elicit from citizens relevant opinions on technoscientific matters. This paper explores the configuration of legitimate constituencies in two such exercises: the UK “GM Nation?” public debate on food biotechnology, and a Swedish “Transparency Forum” on the risks of mobile telephones. We consider the apparently paradoxical combination in these two examples of a tendency to produce static images of the public with a high valuation of mobility—of citizens and their opinions—as the key outcome of deliberation. We discuss the organizers' careful delineation of a distinction between “stakeholders” and the “general public,” and their aversion to any sort of “eventfulness” in public deliberations. Finally, we introduce the classical notion of the “idiot”—the individual who minds exclusively his or her own private affairs— and argue for the need to develop a new vocabulary to evaluate the politics of “listening to the public.

Publics and counter-publics of net-zero

The proliferation of pledges to reach net-zero emissions has revealed a wide range of understandings of what such a pledge entails. The lack of international standards to define decarbonisation pathways and the many kinds of speculative offsets available for net-zero calculations have generated a multiplication of public commitments not tethered to any specific mechanism of accountability. Many have criticised this state of affairs as a governance vacuum allowing extravagant forms of ‘greenwashing,’ with corporations and countries asserting ostensibly ambitious goals without adopting verifiable instruments for their delivery. This paper addresses the situation from a slightly different perspective, exploring instead how net-zero pledges create new climate publics and counter-publics. Drawing on three case studies (UK national net-zero policy, the Race to Zero campaign, and the Science Based Targets Initiative), and informed by a pragmatist understanding of ‘public’ and ‘public formation,’ we examine how the adoption of a formal but ambiguous target leads to a collective consideration of consequences, thus expanding the range of actors engaged in disputes over alternative climate futures

Finding hospitaleras in Vitoria (Spain), an application of the sacramental records

[ES] El objetivo principal de este trabajo es conocer el nombre de las hospitaleras del Hospital Santiago de Vitoria y aportar datos demográficos relacionados con los hospitaleros. Metodología: Consulta de los Registros Sacramentales de Bautismo, Matrimonio y Defunción en Álava entre 1500 y 1820. Resultados principales: Se obtienen nuevos datos de 22 de los 40 hospitaleros conocidos (55%). Se descubre el nombre de 11 nuevas hospitaleras y se relacionan 5 grupos familiares que abarcan 170 años de los 320 a estudio (53'12%). Se obtiene fecha de bautismo de 3 (7,5%) y de defunción de 6 (15%). Conclusión principal: Los registros sacramentales son útiles para el fin propuesto, pasándose de 3 a 14 hospitaleras conocidas. A partir de 1667 es común que los hospitaleros tengan hijos mientras ejercen, siendo excepcional antes. El oficio de hospitalero tenía un gran atractivo en Vitoria.[EN] Aim: To identify the hospitaleras of the Hospital of Santiago in Vitoria, and offer a demographic description of this population. Methodology: The Sacramental Records of Baptism, Marriage and Decease of Alava between the years 1500 and 1820 were reviewed. Results: A further 22 hospitaleros (55%) were identified during this process, which add to the existing 40 known individuals. The names of 11 hospitaleras were obtained. Additionally, 5 families were involved directly in this hospital during 170 years (53,12%) out of the 320 years studied. The date of Baptism of three individuals (7,5%) and the date of Decease of 6 people (15%) were identified. Conclusions: Sacramental records are useful for the intended purpose, as 11 new hospitaleras were identified, adding to the 3 who were already known. From 1667, it was frequent for hospitaleros to marry and have children whilst practicing their profession, where as this was exceptional before this date. The occupation of hospitalero was highly desirable in Vitoria

Perceptions of bioenergy with carbon capture and storage in different policy scenarios

There is growing interest in bioenergy with carbon capture and storage (BECCS) as a possible technology for removing CO2 from the atmosphere. In the first study of its kind, we investigate whether and how different forms of incentivisation impact on public perceptions of this technology. We develop a new experimental method to triangulate perceptions of BECCS in different policy scenarios through quantitative measurement and qualitative elicitation. Here we show that the type of policy instrument used to incentivise BECCS significantly affects perceptions of the technology itself. While we find approval of coercive and persuasion-based policy scenarios for incentivisation, supportive instruments proved polarising. Payments based on the amount of CO2 removed from the atmosphere were approved, but guarantees of higher prices for producers selling energy derived from BECCS were strongly opposed. We conclude that public support for BECCS is inextricably linked to attitudes towards the policies through which it is incentivised