Hamiltonian traffic dynamics in microfluidic-loop networks

Recent microfluidic experiments revealed that large particles advected in a fluidic loop display long-range hydrodynamic interactions. However, the consequences of such couplings on the traffic dynamics in more complex networks remain poorly understood. In this letter, we focus on the transport of a finite number of particles in one-dimensional loop networks. By combining numerical, theoretical, and experimental efforts, we evidence that this collective process offers a unique example of Hamiltonian dynamics for hydrodynamically interacting particles. In addition, we show that the asymptotic trajectories are necessarily reciprocal despite the microscopic traffic rules explicitly break the time reversal symmetry. We exploit these two remarkable properties to account for the salient features of the effective three-particle interaction induced by the exploration of fluidic loops

La força dels microbis

Abstract not availabl

An adaptive admission control and load balancing algorithm for a QoS-aware Web system

The main objective of this thesis focuses on the design of an adaptive algorithm for admission control and content-aware load balancing for Web traffic. In order to set the context of this work, several reviews are included to introduce the reader in the background concepts of Web load balancing, admission control and the Internet traffic characteristics that may affect the good performance of a Web site. The admission control and load balancing algorithm described in this thesis manages the distribution of traffic to a Web cluster based on QoS requirements. The goal of the proposed scheduling algorithm is to avoid situations in which the system provides a lower performance than desired due to servers' congestion. This is achieved through the implementation of forecasting calculations. Obviously, the increase of the computational cost of the algorithm results in some overhead. This is the reason for designing an adaptive time slot scheduling that sets the execution times of the algorithm depending on the burstiness that is arriving to the system. Therefore, the predictive scheduling algorithm proposed includes an adaptive overhead control. Once defined the scheduling of the algorithm, we design the admission control module based on throughput predictions. The results obtained by several throughput predictors are compared and one of them is selected to be included in our algorithm. The utilisation level that the Web servers will have in the near future is also forecasted and reserved for each service depending on the Service Level Agreement (SLA). Our load balancing strategy is based on a classical policy. Hence, a comparison of several classical load balancing policies is also included in order to know which of them better fits our algorithm. A simulation model has been designed to obtain the results presented in this thesis

Sobre la modernitat artística o el passat en el present

Abstract not availabl

El Derecho próximo: una reflexión sobre el entorno jurídico

Abstract not availabl

La química, una ciència central

Abstract not availabl

Canards, Folded Nodes, and Mixed-Mode Oscillations in Piecewise-Linear Slow-Fast Systems

Canard-induced phenomena have been extensively studied in the last three decades, from both the mathematical and the application viewpoints. Canards in slow-fast systems with (at least) two slow variables, especially near folded-node singularities, give an essential generating mechanism for mixed-mode oscillations (MMOs) in the framework of smooth multiple timescale systems. There is a wealth of literature on such slow-fast dynamical systems and many models displaying canard-induced MMOs, particularly in neuroscience. In parallel, since the late 1990s several papers have shown that the canard phenomenon can be faithfully reproduced with piecewise-linear (PWL) systems in two dimensions, although very few results are available in the three-dimensional case. The present paper aims to bridge this gap by analyzing canonical PWL systems that display folded singularities, primary and secondary canards, with a similar control of the maximal winding number as in the smooth case. We also show that the singular phase portraits are compatible in both frameworks. Finally, we show using an example how to construct a (linear) global return and obtain robust PWL MMOs

Darwinisme i genètica: un segle de sinergies i algun fals desencontre

Abstract not availabl

Entre el desconhort i el desencís: el llarg camí de recobrament de la universitat furtada

Abstract not availabl

Función y biogénesis mitocondrial

El objetivo principal de esta tesis se ha centrado en el estudio de las diferencias entre ratas macho y hembra en la morfología, la función y la biogénesis mitocondrial del tejido adiposo marrón (TAM) y del hígado, mediante el análisis de distintas subpoblaciones mitocondriales obtenidas a través del fraccionamiento de la población mitocondrial total. Los resultados han puesto de manifiesto que las diferencias entre géneros a nivel mitocondrial tanto en el TAM y como en el hígado podrían ser atribuidas a la existencia de una subpoblación mitocondrial altamente diferenciada en las hembras, hecho que podría ser indicativo de un proceso de biogénesis mitocondrial distinto entre ambos géneros. Los resultados sugieren la existencia de un factor común a ambos tejidos que influiría en la regulación de dicho proceso. En este sentido, las hormonas sexuales podrían ser uno de los factores candidatos responsables de las diferencias observadas en el presente trabajo.The main goal of this thesis has been focused on the study of gender differences in the mitochondrial morphology, function and biogenesis both in brown adipose tissue (BAT) and in liver, through the analysis of the several mitochondrial subpopulations isolated by means of the fractionation of the whole mitochondrial population. Results have reflected that the gender dimorphism stated in mitochondrial population both in BAT and in liver could be attributed to the existence to more highly differentiated mitochondria in female rats, which could be the result of a different mitochondrial biogenesis process between genders. Since the existence of a common factor which influences this process in both tissues could be hypothesized, sexual hormones could be one of the main factors responsible for the differences described in the present work