Analysis of an epidemic model with awareness decay on regular random networks

The existence of a die-out threshold (different from the classic disease-invasion one) defining a region of slow extinction of an epidemic has been proved elsewhere for susceptible-aware-infectious-susceptible models without awareness decay, through bifurcation analysis. By means of an equivalent mean-field model defined on regular random networks, we interpret the dynamics of the system in this region and prove that the existence of bifurcation for of this second epidemic threshold crucially depends on the absence of awareness decay. We show that the continuum of equilibria that characterizes the slow die-out dynamics collapses into a unique equilibrium when a constant rate of awareness decay is assumed, no matter how small, and that the resulting bifurcation from the disease-free equilibrium is equivalent to that of standard epidemic models. We illustrate these findings with continuous-time stochastic simulations on regular random networks with different degrees. Finally, the behaviour of solutions with and without decay in awareness is compared around the second epidemic threshold for a small rate of awareness decay

Child Development and Autism: Identifying Early Behavioral or Cognitive Markers

Los trastornos del espectro autista constituyen un grupo de alteraciones severas del desarrollo de base genética y neurológica cuyo diagnóstico aún no es sencillo en los primeros meses de vida. Diferentes métodos de investigación han sido empleados para intentar encontrar marcadores comportamentales o cognitivos que permitan su identificación ya en los primeros momentos. Entre los procedimientos utilizados se encuentran los informes familiares retrospectivos, el análisis de videos domésticos o el estudio prospectivo de hermanos de niños con autismo. Las investigaciones realizadas muestran diferencias conductuales a partir de los 12 meses de edad, aunque no antes, en comportamientos como la atención conjunta, la respuesta al nombre, la comunicación verbal y no-verbal, la exploración atípica de los objetos, el desarrollo motor, algunas conductas repetitivas, diferencias en el temperamento y menor capacidad imitativa. Ahora bien, aún persisten divergencias entre los diferentes estudios incluso en lo relativo al papel de estas conductas y, por otro lado, ningún marcador temprano concreto permite en estos momentos predecir de forma aislada y consistente un diagnóstico posterior de autismo.Autism spectrum disorder is a severe developmental disability of genetic and neurological etiology that cannot yet be diagnosed in the first months of life. Different research methods have been used to identify behavioral or cognitive markers that permit early identification of the disorder. Some of the procedures involve parental retrospective reports, analysis of home videos or prospective studies of siblings of children with autism. Research shows differences as from twelve months of age, but not earlier, in behaviors such as joint attention, response to name, delays in verbal and non-verbal communication, atypical exploring of objects, motor delay, certain repetitive behaviors, differences in temperament and reduced imitation. However, conflicting results are still apparent among different studies even in these behaviors. In addition, at this moment no single marker consistently predicts diagnoses of autism at a later age.Ministerio de Ciencia e Innovación de España (proyecto número PSI2010-17401 del Plan Nacional I+D+I

Prensa y movimientos sociales del pasado reciente en México. Cuando la información deviene ideología. El caso del movimiento estudiantil de la UNAM 1999-2000

1 archivo PDF (15 páginas)El movimiento estudiantil de la UNAM de 1999-2000 tuvo una de las coberturas mediáticas más amplias en la trayectoria de los movimientos sociales en el México reciente, considerando además que las llamadas “redes sociales electrónicas” aún no estaban en auge ni tan expandidas socialmente. La importancia académica y política de la UNAM en México, las disputas por el poder en su interior, la historia de luchas estudiantiles surgidas en su seno, las confrontaciones sociales en la época de la consolidación de los ajustes estructurales en la economía, las confrontaciones ideológicas, la consolidación de los medios de comunicación como factor de poder y las campañas electorales por la presidencia de la república en ciernes, que ya anunciaban la ilusión de la denominada “transición democrática”, fueron algunas de las circunstancias que propiciaron que este movimiento estudiantil llamara tanto la atención de los medios de comunicación masiva. El conjunto de estas circunstancias es denominado como “representación de contexto” por Irene Vasilachis y es la operación inicial del proceso de construcción de notas periodísticas por parte de la prensa, es: “… el que alude a la representación textual del contexto social, que está presente en el texto, que se dibuja en proceso de su producción y que se liga a las formas de representación discursiva de la realidad social […además] coexisten dos formas de representar el contexto social, una que lo asocia a una situación de gravedad, contexto catástrofe y otra que lo vincula a un proceso de cambio orientado hacia la modernidad". Por ejemplo, el encabezado de La Jornada del 21 de abril de 1999 dice:“Sin clases 388 mil alumnos de UNAM e IPN”, y abajo una fotografía de dos mujeres haciendo gestos de consternación. El contexto de la imagen, no corresponde al inicio del paro estudiantil, sino a una matanza de estudiantes en una secundaria en Denver, sin embargo, la primera impresión es asociar la fotografía con el encabezado." PALABRAS CLAVE: Student movements. Inquietud estudiantil. Desordenes en el Campus. Activismo estudiantil. Protesta estudiantil. Malestar estudiantil

Finding Optimal Modular Robots for Aerial Tasks

Traditional aerial vehicles have limitations in their capabilities due to actuator constraints, such as motor saturation. The hardware components and their arrangement are designed to satisfy specific requirements and are difficult to modify during operation. To address this problem, we introduce a versatile modular multi-rotor vehicle that can change its capabilities by reconfiguration. Our modular robot consists of homogeneous cuboid modules, propelled by quadrotors with tilted rotors. Depending on the number of modules and their configuration, the robot can expand its actuation capabilities. In this paper, we build a mathematical model for the actuation capability of a modular multi-rotor vehicle and develop methods to determine if a vehicle is capable of satisfying a task requirement. Based on this result, we find the optimal configurations for a given task. Our approach is validated in realistic 3D simulations, showing that our modular system can adapt to tasks with varying requirements

Saddle-node bifurcation of limit cycles in an epidemic model with two levels of awareness

In this paper we study the appearance of bifurcations of limit cycles in an epidemic model with two types of aware individuals. All the transition rates are constant except for the alerting decay rate of the most aware individuals and the rate of creation of the less aware individuals, which depend on the disease prevalence in a non-linear way. For the ODE model, the numerical computation of the limit cycles and the study of their stability are made by means of the Poincar\'e map. Moreover, sufficient conditions for the existence of an endemic equilibrium are also obtained. These conditions involve a rather natural relationship between the transmissibility of the disease and that of awareness. Finally, stochastic simulations of the model under a very low rate of imported cases are used to confirm the scenarios of bistability (endemic equilibrium and limit cycle) observed in the solutions of the ODE model.Comment: 18 page

Robustness of behaviourally-induced oscillations in epidemic models under a low rate of imported cases

This paper is concerned with the robustness of the sustained oscillations predicted by an epidemic ODE model defined on contact networks. The model incorporates the spread of awareness among individuals and, moreover, a small inflow of imported cases. These cases prevent stochastic extinctions when we simulate the epidemics and, hence, they allow to check whether the average dynamics for the fraction of infected individuals are accurately predicted by the ODE model. Stochastic simulations confirm the existence of sustained oscillations for different types of random networks, with a sharp transition from a non-oscillatory asymptotic regime to a periodic one as the alerting rate of susceptible individuals increases from very small values. This abrupt transition to periodic epidemics of high amplitude is quite accurately predicted by the Hopf-bifurcation curve computed from the ODE model using the alerting rate and the infection transmission rate for aware individuals as tuning parameters.Comment: 17 pages, 11 figure

The Role of Multiple Articulatory Channels of Sign-Supported Speech Revealed by Visual Processing

Purpose The use of sign-supported speech (SSS) in the education of deaf students has been recently discussed in relation to its usefulness with deaf children using cochlear implants. To clarify the benefits of SSS for comprehension, 2 eye-tracking experiments aimed to detect the extent to which signs are actively processed in this mode of communication. Method Participants were 36 deaf adolescents, including cochlear implant users and native deaf signers. Experiment 1 attempted to shift observers' foveal attention to the linguistic source in SSS from which most information is extracted, lip movements or signs, by magnifying the face area, thus modifying lip movements perceptual accessibility (magnified condition), and by constraining the visual field to either the face or the sign through a moving window paradigm (gaze contingent condition). Experiment 2 aimed to explore the reliance on signs in SSS by occasionally producing a mismatch between sign and speech. Participants were required to concentrate upon the orally transmitted message. Results In Experiment 1, analyses revealed a greater number of fixations toward the signs and a reduction in accuracy in the gaze contingent condition across all participants. Fixations toward signs were also increased in the magnified condition. In Experiment 2, results indicated less accuracy in the mismatching condition across all participants. Participants looked more at the sign when it was inconsistent with speech. Conclusions All participants, even those with residual hearing, rely on signs when attending SSS, either peripherally or through overt attention, depending on the perceptual conditions.Unión Europea, Grant Agreement 31674

Folding Knots Using a Team of Aerial Robots

From ancient times, humans have been using cables and ropes to tie, carry, and manipulate objects by folding knots. However, automating knot folding is challenging because it requires dexterity to move a cable over and under itself. In this paper, we propose a method to fold knots in midair using a team of aerial vehicles. We take advantage of the fact that vehicles are able to fly in between cable segments without any re-grasping. So the team grasps the cable from the floor, and releases it once the knot is folded. Based on a composition of catenary curves, we simplify the complexity of dealing with an infinite-dimensional configuration space of the cable, and formally propose a new knot representation. Such representation allows us to design a trajectory that can be used to fold knots using a leader-follower approach. We show that our method works for different types of knots in simulations. Additionally, we show that our solution is also computationally efficient and can be executed in real-time.Comment: International Conference on Intelligent Robots and Systems, IROS 2022, Kyoto, Japan, Oct 23 - Oct. 27, 202

Erratum to: A Network Epidemic Model with Preventive Rewiring: Comparative Analysis of the Initial Phase

Erratum de l'article: https://doi.org/10.1007/s11538-016-0227-