Interaction and imitation in a world of Quixotes and Sanchos

Producción CientíficaThis paper studies a two-population evolutionary game in a new setting in between a symmetric and an asymmetric evolutionary model. It distinguishes two types of agents: Sanchos, whose payoffs are defined by a prisoner’s dilemma game, and Quixotes, whose payoffs are defined by a snowdrift game. Considering an imitative revision protocol, a revising agent is paired with someone from his own population or the other population. When matched, they observe payoffs, but not identities. Thus, agents in one population interact and imitate agents from their own population and from the other population. In this setting we prove that a unique mixed-strategy asymptotically stable fixed point of the evolutionary dynamics exists. Taking as an example the compliance with social norms, and depending on the parameters, two type of equilibrium are possible, one with full compliance among Quixotes and partial compliance among Sanchos, or another with partial compliance among Quixotes and defection among Sanchos. In the former type, Sanchos comply above their Nash equilibrium (as they imitate compliant Quixotes). In the latter type, Quixotes comply below their Nash equilibrium (as they imitate defecting Sanchos)

Minimal formulation of the linear spatial analysis of capillary jets: Validity of the two-mode approach

A rigorous and complete formulation of the linear evolution of harmonically stimulated capillary jets should include infinitely many spatial modes to account for arbitrary exit conditions [J. Guerrero et al., J. Fluid Mech. 702, 354 (2012)]. However, it is not rare to find works in which only the downstream capillary dominant mode, the sole unstable one, is retained, with amplitude determined by the jet deformation at the exit. This procedure constitutes an oversimplification, unable to handle a flow rate perturbation without jet deformation at the exit (the most usual conditions). In spite of its decaying behavior, the other capillary mode (subdominant) must be included in what can be called a “minimal linear formulation.” Deformation and mean axial velocity amplitudes at the jet exit are the two relevant parameters to simultaneously find the amplitudes of both capillary modes. Only once these amplitudes are found, the calculation of the breakup length may be eventually simplified by disregarding the subdominant mode. Simple recipes are provided for predicting the breakup length, which are checked against our own numerical simulations. The agreement is better than in previous attempts in the literature. Besides, the limits of validity of the linear formulation are explored in terms of the exit velocity amplitude, the wave number, the Weber number, and the Ohnesorge number. Including the subdominant mode extends the range of amplitudes for which the linear model gives accurate predictions, the criterion for keeping this mode being that the breakup time must be shorter than a given formula. It has been generally assumed that the shortest intact length happens for the stimulation frequency with the highest growth rate. However, we show that this correlation is not strict because the amplitude of the dominant mode has a role in the breakup process and it depends on the stimulation frequency.Ministerio de Economía, Industria y Competitividad, Spain, under Contract No. FIS2014-25161Junta de Andalucía under Contract No. P11-FQM-791

Modificaciones producidas por tratamiento térmico en las propiedades fisicoquímicas de los silicatos de la serie isomorfa montmorillonita-beidelita. I.

68 páginas, 21 figuras, 29 tablas, 64 referencias.[ES]: Continuando investigaciones de uno de nosotros publicadas en trabajos anteriores, se ha realizado un extenso estudio por métodos químicos, fisicoquímicos y difracción de rayos X, acerca de la influencia de la naturaleza del material, cationes de cambio y temperatura de tratamiento sobre la deshidratación reversible e irreversible de la montmorillonita. Las muestras de montmorillonita saturadas con cationes de campo electrostático intenso y gran capacidad de polarización (Li+, Mg++, Zn++, Ce+++. H+) se deshidratan irreversiblemente por calentamiento a temperaturas inferiores a las de eliminación de los OH reticulares. Las muestras saturadas con cationes de campo electrostático débil (Ba++, K+, Rb+) se deshidratan reversiblcmente en las mismas condiciones de tratamiento). La deshidratación irreversible de las muestras de la primera clase citada se debe a la fijación de las láminas por los cationes de cambio deshidratados, alcanzándose una situación estructural semejante a la de las micas. Paralelamente estas muestras experimentan una fuerte reducción en el número de cationes cambiables y en la capacidad de retención de etilenglicol. Se estudia la dependencia de estas reducciones con la temperatura, grado de deshidratación, clase de cationes cambiables y otros factores. Las muestras saturadas con cationes de la segunda clase citada no sufren por el indicado tratamiento reducción alguna sensible en su capacidad de hidratación, número de cationes cambiables ni retención de etilenglicol. La retención de etilenglicol por la montmorillonita depende, como su capacidad de hidratación, de la naturaleza de los cationes de cambio. Las muestras saturadas con los cationes Mg++, Zn++, Ba++, Ce+++, Li+, H+, forman solvatos conteniendo dos capas monomoleculares de glicol entre las láminas del silicato, con un espaciado (001) de 17 A. Las muestras saturadas con los cationes K + o Rb+ dan solvatos conteniendo una sola capa monomolecular de glicol entre las láminas, con un espaciado (001) de 13,2 A. La totalidad de los diagramas de rayos X de las muestras investigadas serán discutidos en otra publicación independiente.[EN]: As a continuation to investigations published in some previous works a extensive study by chemical, physicochemical and X-Ray difractions methods about reversible and irreversible dehydration of montmorillonite, has been carried out. The influence of matherial, exchangeable calions and temperature on the irreversible dehydration and other properties of the montmorillonite have been considered. Samples of montmorillonite saturated with cations having an intense electrostatic field (Li+, Mg++, Zn++, Ce+++, H+) show irreversible dehydration by thermal treatment at temperatures below to those producing the loss of the reticular OH. On the contrary, samples saturated with voluminous cations having a small electrostatic field (Ba++, K+, Rb+, etc.) show reversible dehydration by the same treatment. The relationship of the exchangeable cations to temperature and intensity of the irreversible dehydration, has been studied. Irreversible dehydration produces the fixation of the sheets by interaction with the partially dehydrated exchangeable cations. By this mean, a structural situation like as the micas is reached. Irreversible dehydration of the above mentioned samples reduces strongly the amount of exchangeable cations and the ethylene glicol retention capacity. The relationship of these reductions to temperature of thermal treatment, dehydration grade of the samples, king of exchangeable cations and other factors, are briefly discussed. Samples showing reversible dehydration reduce neither the amount of exchangeable cations nor the ethylene glicol retention. Ethylene glicol retention by montmorillonite depends -as the hydration capacity- on the kind of the exchangeable cations. Adsorption complexes formed by Mg++, Zn++, Ba++, Ce+++, Li+, or H+ montmorillonites, contain two monomolecular layers of ethylene glicol between the structural sheets of the clay mineral. Complexes formed by K+ or Rb+ montmorillonites, contain one monomolecular layer of ethylene glicol belween the structural sheets. These conclusions are confirmed by X-Ray and ethylene glicol retention dates. X-Ray diffractions diagrams of all thermal treated and original samples will be considered in another work.Peer reviewe

Un recorrido por los monstruos de Javier Tomeo

En su narrativa, el escritor Javier Tomeo recurre a lo deforme para que el hombre sea capaz de amar la monstruosidad. El monstruo es el ser que se aleja de la norma, del orden regular de la naturaleza, y llegar a amarlo supone una vía de perfeccionamiento interior que lleva al individuo a mejorar su forma de amar. El objetivo de este artículo es hacer un recorrido por los diversos monstruos que aparecen en la obra del autor, proponiendo una clasificación para estos seres en función de su deformidad y analizando los principales tipos de monstruos que podemos encontrar en cada una de las categorías propuestas.In his narrative, Javier Tomeo uses deformity in order to show the ability of humans to love monstrosity. A monster is a creature outside the norm, which violates the natural order and loving a monster implies an enhancement of our inner selves and a greater capacity for love. The aim of this article is to analyse the range of monsters in Javier Tomeo's work, proposing a classification for these beings according to their deformity and analyzing the main types of monsters that can be found in each of the proposed categories

'A parar la olla': learning from ollas comunes in times of crisis to enhance resilient and just food systems

This paper aims to explore the relationship between resilience and justice, focusing on how grassroots movements can contribute to more resilient food systems, while simultaneously building pathways towards socioenvironmental justice. To address this question, the paper considers a case study situated in the resurgence of ollas comunes in Santiago during the COVID-19 pandemic, in order to learn the relevance of local communities to react, recover and prepare before food insecurity shocks. Using an environmental justice analytical framework, the paper examines the significance of food justice and sovereignty agendas as pathways to developing community resilience, while mobilising changes in the political sphere to reach food justice. At the same time, ollas comunes represent a caring, collective and creative citizen movement that effectively responds to the food emergency of the most vulnerable. Yet, they are often excluded from political decision-making, in which misrecognition and maldistribution impact the capacity of those more exposed to risks in building resilience against future threats in times of multiple crises

The relative nature of fertilization success: Implications for the study of post-copulatory sexual selection

<p>Abstract</p> <p>Background</p> <p>The determination of genetic variation in sperm competitive ability is fundamental to distinguish between post-copulatory sexual selection models based on good-genes vs compatible genes. The sexy-sperm and the good-sperm hypotheses for the evolution of polyandry require additive (intrinsic) effects of genes influencing sperm competitiveness, whereas the genetic incompatibility hypothesis invokes non-additive genetic effects. A male's sperm competitive ability is typically estimated from his fertilization success, a measure that is dependent on the ability of rival sperm competitors to fertilize the ova. It is well known that fertilization success may be conditional to genotypic interactions among males as well as between males and females. However, the consequences of effects arising from the random sampling of sperm competitors upon the estimation of genetic variance in sperm competitiveness have been overlooked. Here I perform simulations of mating trials performed in the context of sibling analysis to investigate whether the ability to detect additive genetic variance underlying the sperm competitiveness phenotype is hindered by the relative nature of fertilization success measurements.</p> <p>Results</p> <p>Fertilization success values render biased sperm competitive ability values. Furthermore, asymmetries among males in the errors committed when estimating sperm competitive abilities are likely to exist as long as males exhibit variation in sperm competitiveness. Critically, random effects arising from the relative nature of fertilization success lead to an underestimation of underlying additive genetic variance in sperm competitive ability.</p> <p>Conclusion</p> <p>The results show that, regardless of the existence of genotypic interactions affecting the output of sperm competition, fertilization success is not a perfect predictor of sperm competitive ability because of the stochasticity of the background used to obtain fertilization success measures. Random effects need to be considered in the debate over the maintenance of genetic variation in sperm competitiveness, and when testing good-genes and compatible-genes processes as explanations of polyandrous behaviour using repeatability/heritability data in sperm competitive ability. These findings support the notion that the genetic incompatibility hypothesis needs to be treated as an alternative hypothesis, rather than a null hypothesis, in studies that fail to detect intrinsic sire effects on the sperm competitiveness phenotype.</p

Design and implementation of a traffic control framework in Firefox OS

Today's smartphones include a rich feature-set as well as various wireless interfaces that provide extra services rather than just voice communication or messaging, as it occurred with traditional mobile phones. Additionally, the widespread use of mobile devices using Third Generation (3G) and Long Term Evolution (LTE) networks has led to the development of various applications (apps) that take advantage of the always-on Internet connectivity provided by these networks (e.g. instant messaging and social network services). Unlike traditional Internet apps (e.g. web surfing and file transfer), the emerging apps that rely on always-on connectivity are often constantly running in the background to receive messages and status updates. This behavior causes that apps continuously generate short app signaling messages such as keep-alive and ping requests to maintain the always-on connectivity. Although the traffic volume of keep-alive messages is not large, frequent short messages can incur a large amount of related signaling traffic in the mobile network. In 3G or LTE networks, the User Equipment (UE) and the Radio Access Network (RAN) keep the Radio Resource Control (RRC) states. The UE stays in Connected mode when it transmits or receives data during active periods and stays in Idle mode during inactive periods. To send even a small data packet, the UE changes the state to the Connected mode prior to transmission. This radio state change generates a lot of network signaling messages, resulting in a rapid increase in traffic loading. Large amounts of network signaling traffic leads to two major problems: rapid drainage of the mobile device's battery and a signaling traffic surge in the mobile network. Since the air interface is a spare resource and the traffic for mobile end devices will grow enormously, it is important that the wireless resources are used in the most efficient way. However, this is not true for current networks as there is not alignment between devices, apps and the network.This document proposes a traffic control framework which acts as an interface between the apps and the network and allows the network operator to aggregate packets prior to transmission. The aggregated packets are sent out at once after a configurable amount of time which means for instance that resources on the wireless link have to be reserved only once for a number of app signaling packets and not for each packet separately. By this the packet transmission will be bursty which will improve network efficiency as the amount of signaling messages is minimized. In addition, battery runtime is improved as lower signaling overhead will reduce the activity time and energy consumption within devices.Hoy en día los smartphones incorporan un amplio conjunto de utilidades, así como varias interfaces inalámbricas que proporcionan servicios adicionales a los ofrecidos por los teléfonos móviles convencionales. Por otra parte, el uso generalizado de las redes 3G y LTE ha originado el desarrollo de numerosas aplicaciones que aprovechan las ventajas que ofrecen dichas redes, un ejemplo son las aplicaciones de redes sociales. Estas aplicaciones, a diferencia de otras como la navegación web o la descarga de archivos, están constantemente ejecutándose en segundo plano y recibiendo notificaciones de actualización de estado. Este comportamiento propicia el intercambio de pequeños mensajes de señalización para mantener la conexión, tales como mensajes "keep alive" o "ping requests". A pesar de que el volumen de estos mensajes no es elevado, su constante intercambio puede ocasionar una gran cantidad de tráfico de señalización en la red. En las redes 3G o LTE, el equipo de usuario (UE) y la red de acceso radio terrestre (RAN) mantienen los estados RRC. El equipo de usuario permanece en el estado activo cuando transmite o recibe datos y retorna al estado de reposo durante los periodos inactivos. El envío de un pequeño paquete de datos supone la transición desde el estado de reposo al estado activo. Este comportamiento genera muchos mensajes de señalización e implica un rápido incremento en el tráfico de la red. Este incremento del tráfico de señalización ocasiona dos grandes problemas: la sobrecarga de la red y un impacto negativo en el consumo de batería de los dispositivos móviles. Es de vital importancia que se haga un uso eficiente de los recursos de red, ya que el aire, en este caso el canal de comunicación, es un medio compartido. Además, se espera que el tráfico generado por los dispositivos móviles crezca enormemente en los próximos años. Las redes móviles actuales no son utilizadas de un modo eficiente debido a la falta de interacción entre la red, los dispositivos móviles y las aplicaciones. Este documento presenta una plataforma de control de tr a co que actúa como interfaz entre las aplicaciones y la red, permitiendo al operador de red agregar los paquetes antes de su transmisión. Esto permite, por ejemplo, que los recursos de red sean reservados s olo una vez para la ráfaga de paquetes y no para cada paquete individualmente, lo cual minimiza la cantidad de mensajes de señalización. Esta propuesta no sólo ayuda a mejorar la eficiencia de la red, sino que además optimiza el uso de la batería, ya que una disminución del tráfico de señalización provoca una reducción del tiempo de actividad y consumo de energía de los dispositivos móviles.Ingeniería Telemátic

Efficiency in the management of urban water services. What have we learned after four decades of research?

The analysis of efficiency in the management of urban water services offers valuable information both for the managers of this service and for public bodies in order to introduce improvements in business practices and in the design of public policies. Since the pioneering study carried out by Ford and Wardford (1969), there have been many attempts to follow this line of research. Due to the importance of the subject and the volume of publications in this field, we believe it is necessary to provide a balance of the work carried out over the last four decades. In this overview, we look at the main questions which have arisen over this period, we provide a synthesis of the results obtained and, finally, we point out some challenges for future research.Water utilities; Efficiency; Firm behaviour; Water