Development of an acoustic transceiver for the KM3NeT positioning system

[EN] In this paper we describe an acoustic transceiver developed for the KM3NeT positioning system. The acoustic transceiver is composed of a commercial free flooded transducer, which works mainly in the 20-40 kHz frequency range and withstands high pressures (up to 500 bars). A sound emission board was developed that is adapted to the characteristics of the transducer and meets all requirements: low power consumption, high intensity of emission, low intrinsic noise, arbitrary signals for emission and the capacity of acquiring the receiving signals with very good timing precision. The results of the different tests made with the transceiver in the laboratory and shallow sea water are described, as well as, the activities for its integration in the Instrumentation Line of the ANTARES neutrino telescope and in a NEMO tower for the in situ tests. © 2012 Elsevier B.V. All rights reserved.This work has been supported by the Ministerio de Ciencia e Innovacion (Spanish Government), Project references FPA2009-13983-C02-02, ACI2009-1067, AIC10-D-00583, and Consolider-Ingenio Multidark (CSD2009-00064). It has also been funded by Generalitat Valenciana, Prometeo/2009/26, and the European 7th Framework Programme, Grant no. 212525.Larosa, G.; Ardid Ramírez, M.; Llorens Alvarez, CD.; Bou Cabo, M.; Martínez Mora, JA.; Adrián Martínez, S.; KM3NeT Consortium (2013). Development of an acoustic transceiver for the KM3NeT positioning system. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 725:215-218. https://doi.org/10.1016/j.nima.2012.11.167S21521872

Ultrasonic transmitter for positioning of the large underwater neutrino telescope KM3NeT

This article belongs to a special issue: 43rd Annual UIA Symposium 23—25 April 2014 CSIC Madrid, Spain. Edited By Margaret Lucas and Enrique Riera[EN] Underwater ultrasonic transducers are commonly used for marine applications including communication and positioning systems. In this work, an ultrasonic transmitter transducer developed for the very large underwater neutrino telescope KM3NeT positioning is presented. The telescope infrastructure will have some degree of motion due to sea current; hence a positioning system is needed in order to monitor the position of the optical sensors. For this purpose, a reliable and affordable positioning based on acoustic systems is used. The ultrasound transmitter prototype developed as part of the positioning system is composed of a commercial FFR transducer and specifically designed electronics to optimize the system and fulfil the requirements of the KM3NeT infrastructure. The transmitter is able to generate high-power short signals with arbitrary waveform in a range of 20 kHz - 40 kHz and withstand high pressures. Signal processing techniques such as advanced cross-correlation methods and filtering as well as broad-band ultrasound signals are also applied for optimizing the acoustic emission and position detection. The work done for a precise laboratory testing and optimization of the system is described. The prototype has been integrated in the ANTARES neutrino telescope for testing its accuracy and the reach in situ. The test results obtained are also presented in this communication.This work has been supported by the Ministerio de Economía y Competitividad (Spanish Government), project ref. FPA2012-37528-C02-02, Multidark (CSD2009-00064) and the European 7th Framework Programme, Grant no. 212525.Saldaña Coscollar, M.; Adrián Martínez, S.; Bou Cabo, M.; Felis Enguix, I.; Larosa, G.; Llorens Alvarez, CD.; Martínez Mora, JA.... (2015). Ultrasonic transmitter for positioning of the large underwater neutrino telescope KM3NeT. Physics Procedia. 63:195-200. https://doi.org/10.1016/j.phpro.2015.03.032S1952006

A compact array calibrator to study the feasibility of acoustic neutrino detection

[EN] Underwater acoustic detection of ultra-high-energy neutrinos was proposed already in 1950s: when a neutrino interacts with a nucleus in water, the resulting particle cascade produces a pressure pulse that has a bipolar temporal structure and propagates within a flat disk-like volume. A telescope that consists of thousands of acoustic sensors deployed in the deep sea can monitor hundreds of cubic kilometres of water looking for these signals and discriminating them from acoustic noise. To study the feasibility of the technique it is critical to have a calibrator able to mimic the neutrino signature that can be operated from a vessel. Due to the axial-symmetry of the signal, their very directive short bipolar shape and the constraints of operating at sea, the development of such a calibrator is very challenging. Once the possibility of using the acoustic parametric technique for this aim was validated with the first compact array calibrator prototype, in this paper we describe the new design for such a calibrator composed of an array of piezo ceramic tube transducers emitting in axial direction.We acknowledge the financial support of the Spanish Ministerio de Economía y Competitividad, Grants FPA2012-37528-C02-02, and Consolider MultiDark CSD2009-00064, of the Generalitat Valenciana, Grants ACOMP/2015/175 PrometeoII/2014/079 and of the European FEDER funds.Ardid Ramírez, M.; Camarena Femenia, F.; Felis-Enguix, I.; Herrero Debón, A.; Llorens Alvarez, CD.; Martínez Mora, JA.; Saldaña-Coscollar, M. (2016). A compact array calibrator to study the feasibility of acoustic neutrino detection. EPJ Web of Conferences. 116(03001):1-4. https://doi.org/10.1051/epjconf/201611603001S141160300

A compact acoustic calibrator for ultra-high energy neutrino detection

With the aim to optimize and test the method of acoustic detection of ultra-high energy neutrinos in underwater telescopes a compact acoustic transmitter array has been developed. The acoustic parametric effect is used to reproduce the acoustic signature of an ultra-high-energy neutrino interaction. Different R&D studies are presented in order to show the viability of the parametric sources technique to deal with the difficulties of the acoustic signal generation: a very directive transient bipolar signal with 'pancake' directivity. The design, construction and characterization of the prototype are described, including simulation of the propagation of an experimental signal, measured in a pool, over a distance of 1 km. Following these studies, next steps will be testing the device in situ, in underwater neutrino telescope, or from a vessel in a sea campaign. (c) 2012 Elsevier B.V. All rights reserved.This work has been supported by the Ministerio de Ciencia e Innovacion (Spanish Government), project references FPA2009-13983-C02-02, ACI2009-1067, Consolider-Ingenio Multidark (CSD2009-00064). It has also been funded by Generalitat Valenciana, Prometeo/2009/26.Adrián Martínez, S.; Ardid Ramírez, M.; Bou Cabo, M.; Larosa, G.; Llorens Alvarez, CD.; Martínez Mora, JA. (2013). A compact acoustic calibrator for ultra-high energy neutrino detection. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 725:219-222. https://doi.org/10.1016/j.nima.2012.11.142S21922272

Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

[no abstract available

Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3b

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC-2020 March 27 17:00 UTC). We conduct two independent searches: A generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate. © 2022. The Author(s). Published by the American Astronomical Society

Comparación de distintas estrategias para la predicción de muerte a corto plazo en el paciente anciano infectado

Objective. The aim of this study was to determine the utility of a post hoc lactate added to SIRS and qSOFA score to predict 30-day mortality in older non-severely dependent patients attended for infection in the Emergency Department (ED). Methods. We performed an analytical, observational, prospective cohort study including patients of 75 years of age or older, without severe functional dependence, attended for an infectious disease in 69 Spanish ED for 2-day three seasonal periods. Demographic, clinical and analytical data were collected. The primary outcome was 30-day mortality after the index event. Results. We included 739 patients with a mean age of 84.9 (SD 6.0) years; 375 (50.7%) were women. Ninety-one (12.3%) died within 30 days. The AUC was 0.637 (IC 95% 0.587-0.688; p= 2 and 0.698 (IC 95% 0.635- 0.761; p= 2. Comparing receiver operating characteristic (ROC) there was a better accuracy of qSOFA vs SIRS (p=0.041). Both scales improve the prognosis accuracy with lactate inclusion. The AUC was 0.705 (IC95% 0.652-0.758; p<0.001) for SIRS plus lactate and 0.755 (IC95% 0.696-0.814; p<0.001) for qSOFA plus lactate, showing a trend to statistical significance for the second strategy (p=0.0727). Charlson index not added prognosis accuracy to SIRS (p=0.2269) or qSOFA (p=0.2573). Conclusions. Lactate added to SIRS and qSOFA score improve the accuracy of SIRS and qSOFA to predict short-term mortality in older non-severely dependent patients attended for infection. There is not effect in adding Charlson index