Sparse Linear Models applied to Power Quality Disturbance Classification

Power quality (PQ) analysis describes the non-pure electric signals that are usually present in electric power systems. The automatic recognition of PQ disturbances can be seen as a pattern recognition problem, in which different types of waveform distortion are differentiated based on their features. Similar to other quasi-stationary signals, PQ disturbances can be decomposed into time-frequency dependent components by using time-frequency or time-scale transforms, also known as dictionaries. These dictionaries are used in the feature extraction step in pattern recognition systems. Short-time Fourier, Wavelets and Stockwell transforms are some of the most common dictionaries used in the PQ community, aiming to achieve a better signal representation. To the best of our knowledge, previous works about PQ disturbance classification have been restricted to the use of one among several available dictionaries. Taking advantage of the theory behind sparse linear models (SLM), we introduce a sparse method for PQ representation, starting from overcomplete dictionaries. In particular, we apply Group Lasso. We employ different types of time-frequency (or time-scale) dictionaries to characterize the PQ disturbances, and evaluate their performance under different pattern recognition algorithms. We show that the SLM reduce the PQ classification complexity promoting sparse basis selection, and improving the classification accuracy

Pseudo-Sylvester domains and skew laurent polynomials over firs

Building on recent work of Jaikin-Zapirain, we provide a homological criterion for a ring to be a pseudo-Sylvester domain, that is, to admit a division ring of fractions over which all stably full matrices become invertible. We use the criterion to study skew Laurent polynomial rings over free ideal rings (firs). As an application of our methods, we prove that crossed products of division rings with free-by-{infinite cyclic} and surface groups are pseudo-Sylvester domains unconditionally and Sylvester domains if and only if they admit stably free cancellation. This relies on the recent proof of the Farrell--Jones conjecture for normally poly-free groups and extends previous results of Linnell--L\"uck and Jaikin-Zapirain on universal localizations and universal fields of fractions of such crossed products

Correlation between capacitances of porous carbons in acidic and aprotic EDLC electrolytes

5 pages, 4 figures, 2 tables.-- Printed version published Jun 2007.A study based on a total of 41 nanoporous carbons shows that there exists a good correlation between the limiting gravimetric capacitances Co at low current densities j (1 mA cm−2) measured in aprotic (1 M (C2H5)4 NBF4 in acetonitrile) and in acidic (2 M aqueous H2SO4) electrolytes. The comparison of the surface-related capacitances (F m−2) of well characterized samples with the amount of thermodesorbed CO suggests a strong contribution of CO generating surface groups to charge storage in the acidic electrolyte, but a negligible contribution in the aprotic medium. It also appears that the decrease of the capacitance with current density is similar in both electrolytes. This confirms that the average micropore width and the CO2 generating surface groups are the main factors which limit the ionic mobility in both electrolytes.Peer reviewe

Multidisciplinary consensus on optimising the detection of NTRK gene alterations in tumours

Fusions de gens; Oncologia molecular; NeoplàsiaFusiones de genes; Oncología molecular; NeoplasiaGene fusions; Molecular oncology; NeoplasmThe recent identification of rearrangements of neurotrophic tyrosine receptor kinase (NTRK) genes and the development of specific fusion protein inhibitors, such as larotrectinib and entrectinib, have revolutionised the diagnostic and clinical management of patients presenting with tumours with these alterations. Tumours that harbour NTRK fusions are found in both adults and children; and they are either rare tumours with common NTRK fusions that may be diagnostic, or more prevalent tumours with rare NTRK fusions. To assess currently available evidence on this matter, three key Spanish medical societies (the Spanish Society of Medical Oncology (SEOM), the Spanish Society of Pathological Anatomy (SEAP), and the Spanish Society of Paediatric Haematology and Oncology (SEHOP) have brought together a group of experts to develop a consensus document that includes guidelines on the diagnostic, clinical, and therapeutic aspects of NTRK-fusion tumours. This document also discusses the challenges related to the routine detection of these genetic alterations in a mostly public Health Care System.SEOM, SEAP and SEHOP have received financial support for this project in the form of unrestricted collaboration in the logistics of expert meeting from Bayer and Roche

Datos sobre el tesorillo tardorromano de monedas de El Pedregal (Chantada, Lugo)

Se presentan los datos sobre el contexto de aparición del Tesorillo Tardorromano de monedas de bronce de El Pedregal, descubierto a raíz de unas obras de canalización. Se ha realizado un estudio sobre una pequeña muestra entre las monedas mejor conservadas de las más de 10.000 monedas que lo componían, identificando la cronología y el metal empleado. En los análisis de composición se ha utilizado la técnica no destructiva de espectrometría por fluorescencia de rayos X.The paper deals with the archaeological context of the hoard of Late Roman bronze coins found in El Pedregal after some public works. The hoard contains more than ten thousand coins. A small group choosen among the better preserved coins has been studied to define the chronology and the metal used. Non-destructive x-ray fluorescence (XRF) spectrometry was used for elemental analysis

An anodeless (bare) tether experiment

NETT (New Electrodynamic Tether Technology) is an experiment proposed to ESA in 1991 as part of the Columbus Precursor Flights. It was originally intended to fly as an exposed payload in the Shuttle cargo bay. The main purpose was to demonstrate the electrodynamical capabilities of the innovative "bare tether" concept. The proposed conceptual design was recommended by a Scientific Panel of ESA, meeting in Heidelberg in March 1992. Unfortunately, the Precursor Flights have all but been scuttled, particularly as far as exposed payloads are concerned. The experiment, horever, is being considered in accomodation studies (APLSS, PIERS) for the European modulus of the future Space Station. Additionally, it might be possible to fly the bare tether in a Russian spacecraft