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In the quest for high-performance quantum thermal machines, looking for an optimal thermodynamic efficiency is only part of the issue. Indeed, at the level of quantum devices, fluctuations become extremely relevant and need to be taken into account. In this paper we study the thermodynamic uncertainty relations for a quantum thermal machine with a quantum harmonic oscillator as a working medium, connected to two thermal baths, one of which is dynamically coupled. We show that parameters can be found such that the machine operates both as a quantum engine or refrigerator, with both sizeable efficiency and small fluctuations., Comment: Original submitted version of the manuscript: 13 pages, 4 figures

We discuss whether, and under which conditions, it is possible to realize a heat engine simply by dynamically modulating the couplings between the quantum working medium and thermal reservoirs. For that purpose, we consider the paradigmatic model of a quantum harmonic oscillator, exposed to a minimal modulation, that is, a monochromatic driving of the coupling to only one of the thermal baths. We demonstrate, at any order in the system/bath coupling strength, that in this setup non--Markovianity of the bath is a necessary condition to obtain a heat engine. In addition, we identify suitable structured environments for the engine to approach the ideal Carnot efficiency. Our results open up new possibilities for the use of non--Markovian open quantum systems for the construction and optimization of quantum thermal machines., Comment: Final revision as published on Physical Review Research: 19 pages, 7 color figures

Industry 4.0 represents a new industrial revolution that will dramatically change the landscape in many sectors, including manufacturing and logistics. Robotics, machine intelligence, and new forms of connectivity are key ingredients of this paradigm. 5G mobile networks are expected to play a crucial role, supporting a lower cost per transported bit in air and a lower latency compared with 4G. 5G radio ensures different performance levels in very heterogeneous coverage situations, including a mix of indoor and outdoor contexts. Mobile network evolution requires new transport networks to address the new challenging requirements: increasing transmission capacity, compatibility with latency-critical applications, significantly reduced cost with respect to conventional metro network segments, lower energy consumption, and, in some cases, switching capabilities. Optical communications and networking will play a key role in these new transport scenarios, where tailored transmission techniques and network architectures are needed. This paper discusses the requirements and challenges that Industry 4.0 scenarios pose to optical communications and networking architectures. Performance of optical transmission schemes, tailored to support these new radio access networks, are detailed and benchmarked. A network test bed, focused on transport for vertical use cases, is described. Experimental results demonstrate the compliance of the proposed optical transport network with a latency-critical cloud robotics application, which presents industry-grade connectivity needs. The authors acknowledge Stephane Lessard, Teresa Pepe, Marzio Puleri, Eris Seder, Stefano Stracca, Francesco Testa, and Fabio Ubaldi, for relevant discussions and information about their research work. This work has been partially supported by the EC H2020 5GPPP 5Growth project (grant 856709).

The increasing stress on mobi le radio access performance in a context of declining revenues for operators is requiring the evolution of transport networks (backhaul and fronthaul), which currently work decoupled. The heterogeneity of the nodes and transmission technologies inter-connecting the fronthaul and backhaul segments makes the network quite complex, costly and inefficient to manage flexibly and dynamically. In order to meet 5G requirements in a cost-effective manner, 5G-Crosshaul is designing a 5G transport network that unifies the data, control, and management planes . This paper presents one of the main concepts proposed within 5G-Crosshaul project, a novel multi-layer switch architecture that enables the multiplexing of fronthaul and backhaul traffic within the same transport network to achieve the proposed unified data-plane.

The charge and spin patterns of a quantum dot embedded into a spin-orbit coupled quantum wire subject to a magnetic field are investigated. A Luttinger liquid theory is developed, taking into account open boundaries and finite magnetic field. In the quasi-helical regime, when spin-orbit effects dominate over the Zeeman interaction, peculiar states develop at the Fermi surface of the dot. Anomalous Friedel oscillations with twice the expected wavelength develop in the wavefunction of collective excitations of such states, accompanied by peculiar spin patterns in their magnetization. Both effects are analyzed in detail and shown possible to be probed in transport experiments. The stability against electron interactions and magnetic field is investigated. We also discuss how signatures of such states survive in the total charge and spin densities.

We study the spin ordering of a quantum dot defined via magnetic barriers in an interacting quantum spin Hall edge. The spin-resolved density-density correlation functions are computed. We show that strong electron interactions induce a ground state with a highly correlated spin pattern. The crossover from the liquid-type correlations at weak interactions to the ground state spin texture found at strong interactions parallels the formation of a one-dimensional Wigner molecule in an ordinary strongly interacting quantum dot., Comment: Accepted for publication on Physica Status Solidi - Rapid Research Letters (early view)

161 p. Brain stroke is the second cause of death worldwide. Among the cerebrovascular accidents, ischemic stroke is the most common. It is caused by an interruption of blood flow, and it is characterized by sudden neuronal death (necrosis in the core) and apoptotic neuronal loss in the penumbra. After the generation of the glial scar surrounding the penumbra, ischemia in animal model can activate the neurogenic machinery in the subventricular zone (SVZ). However, the rapid formation of the glial scar after brain ischemia represents a double edged sword for brain survival. On one side, the ischemic scar isolates the healthy tissues from deadly factors released in the ischemic core but on the other hand, it impedes the neuronal regeneration from the SVZ. Previous results in our laboratory demonstrated that high levels of extracellular adenosine, one of the factors released after brain ischemia, could activate theSVZ and generate new astrocytes. In this PhD project, we used a mice model of transient brain ischemia by middle cerebral artery occlusion (MCAO) to accomplish the following objectives:1) To characterize the SVZ activation and astrogliogenesis following brain ischemia;2) To investigate the role of newborn astrocytes generated from the SVZ.By combining immunofluorescence with genetic cellular tracing (in vivo electroporation of neural progenitor cells) we demonstrated that brain ischemia induced the generation of newborn astrocytes from the SVZ. Newborn astrocytes expressed the specific marker Thbs4 and were derived from the activated Type B cells at the dorsal SVZ. The neural stem cells and the Thbs4 astrocytes generated from the SVZ, deviated their physiological route to the olfactory bulb and reached the ischemic scar. Here, astrocytes generated after brain ischemia could degrade and synthetize the hyaluronic acid of the extracellular matrix suggesting a dual role in the modulation of the ischemic glial scar. We demonstrated for the first time that astrocytes derived from SVZ can produce, uptake and degrade the hyaluronic acid of the extracellular matrix. Our results can open a new pharmacological strategy to modulate the formation and the remodeling of the glial scar, facilitate the tissue regeneration after brain ischemia, and propose astroglia as a possible pharmacological target Achucarro: Basque Center for Neuroscience

135 p. La enfermedad de Parkinson (EP) se caracteriza principalmente por la presencia de inclusiones citoplasmáticas llamadas cuerpos de Lewy, cuyo principal componente es la ¿-sinucleína y la pérdida de neuronas dopaminérgicas en la sustancia negra. Los astrocitos constituyen el subtipo glial más abundante en el cerebro, que cubre funciones esenciales para la homeostasis cerebral y la salud neuronal. La disfunción de la biología de los astrocitos en el mesencéfalo puede derivar en el daño de las neuronas dopaminérgicas y una mayor propagación de la EP.En este estudio, hemos utilizado dos modelos diferentes con el objetivo de comprender el papel de los astrocitos en el inicio y la propagación de la EP y descifrar el mecanismo celular que caracteriza el metabolismo de astrocitos en la patología. Por un lado hemos utilizado una quimera in vitro tratando células de rata con extractos de LB humanos. Por otro lado hemos generado y caracterizado astrocitos humanos derivados de iPS de pacientes con EP que portan la mutación LRRK2G2019S.Hemos podido concluir que los astrocitos disfuncionales cubren un papel esencial en el inicio y la progresión de la EP. Tanto la acumulación de ¿-syn como la mutación LRRK2G2019S inducen un desequilibrio mitocondrial que conduce al daño celular y a la degeneración neuronal final. Este estudiopropone un nuevo objetivo terapéutico posible dirigido a mantener la funcionalidad astrocítica. Se necesitan más experimentos para establecer las vías mediante las que los astrocitos podrían inducir la muerte dopaminérgica

268 p. : il., Este trabajo de Tesis Doctoral presenta el desarrollo, la caracterización y la validación de un nuevo soporte polimérico capaz de inducir la diferenciación neuronal in vitro, combinando técnicas de fotolitografía y de tecnología de matrices extracelulares. Además, se ha estudiado su capacidad de liberación de moléculas señalizadoras para comprobar la optimización de este nuevo sistema frente a los sistemas clásicos de cultivo. La biocompatibilidad y eficiencia en la diferenciación neuronal y dopaminérgica sobre el soporte desarrollado, se ha comprobado tanto a nivel de línea celular establecida (PC12) como a nivel de cultivos primarios. En este caso, se han utilizado tres tipos de células: (i) células de hipocampo de rata embrionaria (E18), (ii) células precursoras neurales de zona subventricular de rata neonata (P2-P3), y (iii) células precursoras derivadas de piel de rata adulta. Con estos tres tipos celulares se ha pretendido demostrar, respectivamente, (i) la capacidad de diferenciación neuronal de células ya determinadas al linaje neuronal en estadíos tempranos de desarrollo (embrionario); (ii) la capacidad de diferenciación no sólo neuronal sino también dopaminérgica de células pluripotentes neurales, con capacidad de plasticidad y relacionadas con la neurogénesis adulta; y (iii) la respuesta de células de origen no neural, descritas en la literatura como una fuente importante de células precursoras neurales con potencialidad en transplantes autólogos. Como conclusión global al trabajo presentado, se puede decir que el cultivo de células precursoras neurales en sustratos tridimensionales con componentes similares a la propia matriz extracelular neural, representa un medio eficaz para el desarrollo de nuevos tejidos neurales transplantables, pudiendo servir como una estrategia prometedora en el tratamiento de Enfermedades Neurodegenerativas como, por ejemplo, la Enfermedad de Parkinson. Además, el cultivo de otros tipos celulares en el soporte desarrollado puede servir como modelo de liberación controlada de moléculas implicadas en la diferenciación celular, o como modelo para el estudio de moléculas implicadas en diferentes enfermedades.