RED: Deep Recurrent Neural Networks for Sleep EEG Event Detection

The brain electrical activity presents several short events during sleep that can be observed as distinctive micro-structures in the electroencephalogram (EEG), such as sleep spindles and K-complexes. These events have been associated with biological processes and neurological disorders, making them a research topic in sleep medicine. However, manual detection limits their study because it is time-consuming and affected by significant inter-expert variability, motivating automatic approaches. We propose a deep learning approach based on convolutional and recurrent neural networks for sleep EEG event detection called Recurrent Event Detector (RED). RED uses one of two input representations: a) the time-domain EEG signal, or b) a complex spectrogram of the signal obtained with the Continuous Wavelet Transform (CWT). Unlike previous approaches, a fixed time window is avoided and temporal context is integrated to better emulate the visual criteria of experts. When evaluated on the MASS dataset, our detectors outperform the state of the art in both sleep spindle and K-complex detection with a mean F1-score of at least 80.9% and 82.6%, respectively. Although the CWT-domain model obtained a similar performance than its time-domain counterpart, the former allows in principle a more interpretable input representation due to the use of a spectrogram. The proposed approach is event-agnostic and can be used directly to detect other types of sleep events.Comment: 8 pages, 5 figures. In proceedings of the 2020 International Joint Conference on Neural Networks (IJCNN 2020

Infrared propagators of Yang-Mills theory from perturbation theory

We show that the correlation functions of ghosts and gluons for the pure Yang-Mills theory in Landau gauge can be accurately reproduced for all momenta by a one-loop calculation. The key point is to use a massive extension of the Faddeev-Popov action. The agreement with lattice simulation is excellent in d=4. The one-loop calculation also reproduces all the characteristic features of the lattice simulations in d=3 and naturally explains the pecularities of the propagators in d=2.Comment: 4 pages, 4 figures

Hi ha una història social de la llengua catalana?

La lingüística històrica ha produït al llarg de l'últimsegle estudis notables sobre l'evolució formal de la llengua catalana. A més, en les últimes dècades s'ha desenvolupat una sociolingüística catalana que connecta la teoria i la descripció empírica amb la política lingüística. No obstant això, no s'ha gestat una història social de la llengua, o una sociolingüística històrica en sentit estricte, més enllà d'alguns esforços individuals. Les raons d'aquest dèficit són internes (les limitacions de l'objecte d'estudi, la inèrcia i l'estancament dels estudis filològics...) i externes (els condicionants sociopolítics i de mercat que pesen sobre el català). Per això es proposa avançar cap a un nou paradigma en què la diacronia lingüística s'integri dins de les ciències socials, obertes a l'autocrítica i la superació de l'apriorisme ideològic.Does the Catalan language have a social history?. Over the last century, historical linguistics has produced notable studies on the formal evolution of the Catalan language.Moreover, in recent decades Catalan sociolinguistics has been developed, connecting theory and empirical description to language policy. However, a social history of the Catalan language has not been developed nor historical sociolinguistics, strictly speaking, bar a few random examples. The reasons for this deficit are both internal (the limitations of the subject matter, the inertia and the stagnation of philological studies…) and external (the socio-political andmarket constraints imposed on the Catalan language). We therefore propose to move towards a new paradigm in which the linguistic diachrony is integrated within social sciences, open to self-criticism and to overcoming ideological apriorism

Transport and invariant manifolds near L3 in the Earth-Moon Bicircular model

This paper focuses on the role of $\mathrm{L}_3$ to organise trajectories for a particle going from Earth to Moon and viceversa, and entering or leaving the Earth-Moon system. As a first model, we have considered the planar Bicircular problem to account for the gravitational effect of the Sun on the particle. The first step has been to compute a family of hyperbolic quasi-periodic orbits near $\mathrm{L}_3$. Then, the computation of their stable and unstable manifolds provides connections between Earth and Moon, and also generates trajectories that enter and leave the Earth-Moon system. Finally, by means of numerical simulations based on the JPL ephemeris we show that these connections can guide the journey of lunar ejecta towards the Earth