Strategies for the Integration of quantum networks for a future quantum internet

The great scientific and technological advances that are being carried out in the field of quantum communications, accompanied by large investment programs such as EuroQCI, are driving the deployment of quantum network throughout the world. One of the final long-term objectives is to achieve the development of a quantum internet that provides greater security in its services and new functionalities that the current internet does not have. This article analyzes the possible integration strategies of already deployed networks or in the process of being deployed in order to reach a future global quantum network. Two strategies based on the SDN paradigm are proposed, based on a hierarchical controller scheme and on a distributed model. Each of these approaches shows pros and cons and could be applicable in different use cases. To define these strategies, the most relevant deployments of quantum communications networks carried out to date has been analyzed, as well as the different approaches for a quantum network architecture and topology, and the various proposed definitions of what quantum internet is and what are the components that would make it up in an ideal scenario. Finally, several detected opportunities and challenges regarding security and technological aspects are presented

Evidence for quasicritical brain dynamics

Much evidence seems to suggest cortex operates near a critical point, yet a single set of exponents defining its universality class has not been found. In fact, when critical exponents are estimated from data, they widely differ across species, individuals of the same species, and even over time, or depending on stimulus. Interestingly, these exponents still approximately hold to a dynamical scaling relation. Here we show that the theory of quasicriticality, an organizing principle for brain dynamics, can account for this paradoxical situation. As external stimuli drive the cortex, quasicriticality predicts a departure from criticality along a Widom line with exponents that decrease in absolute value, while still holding approximately to a dynamical scaling relation. We use simulations and experimental data to confirm these predictions and describe new ones that could be tested soon.Comment: 5 pages, 4 figure

Tracking the COVID-19 Crisis with High-Resolution Transaction Data

We exploit high-frequency/high-resolution transaction data from BBVA, the second-largest bank in Spain, to analyse the dynamics of expenditure in Spain during the ongoing COVID-19 pandemic. Our main dataset consists of the universe of BBVA-mediated sales transactions from both credit cards and point-of-sales terminals, and totals 1.4 billion individual transactions since 2019. This dataset provides a unique opportunity to study the impact of the ongoing crisis in Spain—and the policies put in place to control it—on a daily basis. We find little shift in expenditure prior to the national lockdown, but then immediate, very large, and sustained expenditure reductions thereafter. Transaction metadata also allows us to study variation in these reductions across geography, sectors, and mode of sale (e.g. online/offline). We conclude that transaction data captures many salient patterns in how an economy reacts to shocks in real time, which makes its potential value to policy makers and researchers high

One year follow-up of a randomized trial with a dilemma-focused intervention for depression: Exploring an alternative to problem-oriented strategies

© 2018 Feixas et al.Cognitive behavioural therapy (CBT) is aimed to counteract cognitions and behaviours that are considered as dysfunctional. The aim of the study is to test whether the inclusion of a non-counteractive approach (dilemma-focused intervention, DFI) in combination with CBT group therapy will yield better short- and long-term outcomes than an intervention conducted entirely using CBT.Peer reviewedFinal Published versio

Determining future aflatoxin contamination risk scenarios for corn in Southern Georgia, USA using spatio-temporal modelling and future climate simulations

© The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.Aflatoxins (AFs) are produced by fungi in crops and can cause liver cancer. Permitted levels are legislated and batches of grain are rejected based on average concentrations. Corn grown in Southern Georgia (GA), USA, which experiences drought during the mid-silk growth period in June, is particularly susceptible to infection by Aspergillus section Flavi species which produce AFs. Previous studies showed strong association between AFs and June weather. Risk factors were developed: June maximum temperatures > 33 °C and June rainfall  33 °C and rainfall < 50 mm increased and then plateaued for both emissions scenarios. The percentage of years thresholds were exceeded was greater for RCP 8.5 than RCP 4.5. The spatial distribution of high-risk counties changed over time. Results suggest corn growth distribution should be changed or adaptation strategies employed like planting resistant varieties, irrigating and planting earlier. There were significantly more counties exceeding thresholds in 2010-2040 compared to 2000-2030 suggesting that adaptation strategies should be employed as soon as possible.Peer reviewe

HetSAGE: Heterogenous Graph Neural Network for Relational Learning

This paper aims to bridge this gap between neuro-symbolic learning (NSL) and graph neural networks (GNN) approaches and provide a comparative study. We argue that the natural evolution of NSL leads to GNNs, while the logic programming foundations of NSL can bring powerful tools to improve the way how information is represented and pre-processed for the GNN. In order to make this comparison, we propose HetSAGE, a GNN architecture that can efficiently deal with the resulting heterogeneous graphs that represent typical NSL learning problems. We show that on CORA, MUTA188 and MovieLens our approach outperforms the state-of-the-art in NSL

Generation of arbitrary complex quasi-non-diffracting optical patterns

Due to their unique ability to maintain an intensity distribution upon propagation, non-diffracting light fields are used extensively in various areas of science, including optical tweezers, nonlinear optics and quantum optics, in applications where complex transverse field distributions are required. However, the number and type of rigorously non-diffracting beams is severely limited because their symmetry is dictated by one of the coordinate system where the Helmholtz equation governing beam propagation is separable. Here, we demonstrate a powerful technique that allows the generation of a rich variety of quasi-non-diffracting optical beams featuring nearly arbitrary intensity distributions in the transverse plane. These can be readily engineered via modifications of the angular spectrum of the beam in order to meet the requirements of particular applications. Such beams are not rigorously non-diffracting but they maintain their shape over large distances, which may be tuned by varying the width of the angular spectrum. We report the generation of unique spiral patterns and patterns involving arbitrary combinations of truncated harmonic, Bessel, Mathieu, or parabolic beams occupying different spatial domains. Optical trapping experiments illustrate the opto-mechanical properties of such beams.Comment: 11 pages, 7 figures, to be published in Optics Expres

Fermi level tuning and double-dome superconductivity in the kagome metal CsV3Sb5-xSnx

The recently reported AV3Sb5 (A = K, Rb, Cs) family of kagome metals are candidates for unconventional superconductivity and chiral charge density wave (CDW) order; both potentially arise from nested saddle points in their band structures close to the Fermi energy. Here, we use chemical substitution to introduce holes into CsV3Sb5 and unveil an unconventional coupling of the CDW and superconducting states. Specifically, we generate a phase diagram for CsV3Sb5−xSnx that illustrates the impact of hole doping the system and lifting the nearest van Hove singularity toward and above EF. Superconductivity exhibits a nonmonotonic evolution with the introduction of holes, resulting in two “domes” peaked at 3.6 and 4.1 K and the rapid suppression of three-dimensional CDW order. The evolution of CDW and superconducting order is compared with the evolution of the electronic band structure of CsV3Sb5−xSnx, where the complete suppression of superconductivity seemingly coincides with an electronlike band comprised of Sb pz orbitals pushed above EF

Status of IGEX dark matter search at Canfranc Underground Laboratory

One IGEX 76Ge double-beta decay detector is currently operating in the Canfranc Underground Laboratory in a search for dark matter WIMPs, through the Ge nuclear recoil produced by the WIMP elastic scattering. In this talk we report on the on-going efforts to understand and eventually reject the background at low energy. These efforts have led to the improvement of the neutron shielding and to partial reduction of the background, but still the remaining events are not totally identified. A tritium contamination or muon-induced neutrons are considered as possible sources, simulations and experimental test being still under progress. According to the success of this study we comment the prospects of the experiment as well as those of its future extension, the GEDEON dark matter experiment.Comment: 6 pages, 3 figures, talk given at 4th International Workshop on the Identification of Dark Matter, York, September 200