Status and Recent Results of the Acoustic Neutrino Detection Test System AMADEUS

The AMADEUS system is an integral part of the ANTARES neutrino telescope in the Mediterranean Sea. The project aims at the investigation of techniques for acoustic neutrino detection in the deep sea. Installed at a depth of more than 2000m, the acoustic sensors of AMADEUS are based on piezo-ceramics elements for the broad-band recording of signals with frequencies ranging up to 125kHz. AMADEUS was completed in May 2008 and comprises six "acoustic clusters", each one holding six acoustic sensors that are arranged at distances of roughly 1m from each other. The clusters are installed with inter-spacings ranging from 15m to 340m. Acoustic data are continuously acquired and processed at a computer cluster where online filter algorithms are applied to select a high-purity sample of neutrino-like signals. 1.6 TB of data were recorded in 2008 and 3.2 TB in 2009. In order to assess the background of neutrino-like signals in the deep sea, the characteristics of ambient noise and transient signals have been investigated. In this article, the AMADEUS system will be described and recent results will be presented.Comment: 7 pages, 8 figures. Proceedings of ARENA 2010, the 4th International Workshop on Acoustic and Radio EeV Neutrino Detection Activitie

Calibration of the Logarithmic-Periodic Dipole Antenna (LPDA) Radio Stations at the Pierre Auger Observatory using an Octocopter

An in-situ calibration of a logarithmic periodic dipole antenna with a frequency coverage of 30 MHz to 80 MHz is performed. Such antennas are part of a radio station system used for detection of cosmic ray induced air showers at the Engineering Radio Array of the Pierre Auger Observatory, the so-called Auger Engineering Radio Array (AERA). The directional and frequency characteristics of the broadband antenna are investigated using a remotely piloted aircraft (RPA) carrying a small transmitting antenna. The antenna sensitivity is described by the vector effective length relating the measured voltage with the electric-field components perpendicular to the incoming signal direction. The horizontal and meridional components are determined with an overall uncertainty of 7.4^{+0.9}_{-0.3} % and 10.3^{+2.8}_{-1.7} % respectively. The measurement is used to correct a simulated response of the frequency and directional response of the antenna. In addition, the influence of the ground conductivity and permittivity on the antenna response is simulated. Both have a negligible influence given the ground conditions measured at the detector site. The overall uncertainties of the vector effective length components result in an uncertainty of 8.8^{+2.1}_{-1.3} % in the square root of the energy fluence for incoming signal directions with zenith angles smaller than 60{\deg}.Comment: Published version. Updated online abstract only. Manuscript is unchanged with respect to v2. 39 pages, 15 figures, 2 table

Acoustic and optical variations during rapid downward motion episodes in the deep north-western Mediterranean Sea

An Acoustic Doppler Current Profiler (ADCP) was moored at the deep-sea site of the ANTARES neutrino telescope near Toulon, France, thus providing a unique opportunity to compare high-resolution acoustic and optical observations between 70 and 170 m above the sea bed at 2475 m. The ADCP measured downward vertical currents of magnitudes up to 0.03 m s-1 in late winter and early spring 2006. In the same period, observations were made of enhanced levels of acoustic reflection, interpreted as suspended particles including zooplankton, by a factor of about 10 and of horizontal currents reaching 0.35 m s-1. These observations coincided with high light levels detected by the telescope, interpreted as increased bioluminescence. During winter 2006 deep dense-water formation occurred in the Ligurian subbasin, thus providing a possible explanation for these observations. However, the 10-20 days quasi-periodic episodes of high levels of acoustic reflection, light and large vertical currents continuing into the summer are not direct evidence of this process. It is hypothesized that the main process allowing for suspended material to be moved vertically later in the year is local advection, linked with topographic boundary current instabilities along the rim of the 'Northern Current'.Comment: 30 pages, 7 figure

The positioning system of the ANTARES Neutrino Telescope

The ANTARES neutrino telescope, located 40km off the coast of Toulon in the Mediterranean Sea at a mooring depth of about 2475m, consists of twelve detection lines equipped typically with 25 storeys. Every storey carries three optical modules that detect Cherenkov light induced by charged secondary particles (typically muons) coming from neutrino interactions. As these lines are flexible structures fixed to the sea bed and held taut by a buoy, sea currents cause the lines to move and the storeys to rotate. The knowledge of the position of the optical modules with a precision better than 10cm is essential for a good reconstruction of particle tracks. In this paper the ANTARES positioning system is described. It consists of an acoustic positioning system, for distance triangulation, and a compass-tiltmeter system, for the measurement of the orientation and inclination of the storeys. Necessary corrections are discussed and the results of the detector alignment procedure are described

A FORMAÇÃO DO EU E SUA RELAÇÃO COM A FINITUDE

No texto A transitoriedade, Freud discorre sobre a finitude, à qual todas as coisas estão destinadas. A discussão psicanalítica a respeito do tema pode ser tratada com o texto Introdução ao Narcisismo, no qual Freud apresenta uma teoria da formação do Eu. É a partir da renúncia advinda da impossibilidade de satisfação pulsional infinita, que uma nova instância psíquica é inaugurada: justamente o Eu. Com esta renúncia, o objeto primevo de satisfação da pulsão existe apenas em sua condição de irrepresentável, só pode ser conhecido através de substitutos - esses sim, finitos. Nesse sentido, a transitoriedade aponta para uma incapacidade humana por estrutura de abdicar de uma questão que é constitutiva do sujeito: a de jamais conhecer a si mesmo plenamente. Esse processo é fundamental para que se experimente a transitoriedade, ou seja, a vida enquanto finita. O objetivo do presente trabalho é investigar, à luz desses dois textos de Freud, de que maneira a reflexão sobre a morte é estruturante na vida psíquica. Mais particularmente procuramos abordá-la no contexto hospitalar de pessoas acometidas pelo câncer. Partindo muitas vezes da iminência da morte, visamos a debater o importante tema de como a constituição narcísica, ou seja, o Eu, preside as relações dos pacientes oncológicos com o que lhe está acontecendo. A pesquisa Corpo e Finitude, é uma parceria entre o Instituto de Psicologia e o Instituto Nacional do Câncer e busca compreender os efeitos para o funcionamento psíquico daqueles que sofrem alterações corporais devido ao câncer. Deste modo, a metodologia que utilizamos é a da primazia clínica apresentada pelos profissionais da saúde em confluência com os estudos teóricos da psicanálise. A partir desse movimento contínuo de retorno ao tratamento singular de cada caso, construímos, a cada vez, o aprimoramento de uma direção de cuidado

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Hepatitis C virus in vitro replication is efficiently inhibited by acridone Fac4

Hepatitis C Virus (HCV) affects about 170 million people worldwide. The current treatment has a high cost and variable response rates according to the virus genotype. Acridones, a group of compounds extracted from natural sources, showed potential antiviral actions against HCV. Thus, this study aimed to evaluate the effect of a panel of 14 synthetic acridones on the HCV life cycle. The compounds were screened using an Huh7.5 cell line stably harboring the HCV genotype 2a subgenomic replicon SGR-JFH1-FEO. Cells were incubated in the presence or absence of compounds for 72 hours and cell viability and replication levels were assessed by MTT and luciferase assays, respectively. The acridone Fac4 at 5 μM inhibited approximately 90% of HCV replication with 100 % of cell viability. The effects of Fac4 on virus replication, entry and release steps were evaluated in Huh7.5 cells infected with the JFH-1 isolate of HCV (HCVcc). Fac4 inhibited approximately 70 % of JFH-1 replication, while no effect was observed on virus entry. The antiviral activity of Fac4 was also observed on the viral release, with almost 80% of inhibition. No inhibitory effect was observed against genotype 3 replication. Fac4 demonstrated 40% of intercalation into dsRNA, however did not inhibit T7 polymerase activity, as well as translation by IRES interaction. Although its mode of action is partly understood, the Fac4 presents significant inhibition of Hepatitis C virus replication and can therefore be considered as a candidate for the development of a future anti-HCV treatment

Coinfection with Different Trypanosoma cruzi Strains Interferes with the Host Immune Response to Infection

A century after the discovery of Trypanosoma cruzi in a child living in Lassance, Minas Gerais, Brazil in 1909, many uncertainties remain with respect to factors determining the pathogenesis of Chagas disease (CD). Herein, we simultaneously investigate the contribution of both host and parasite factors during acute phase of infection in BALB/c mice infected with the JG and/or CL Brener T. cruzi strains. JG single infected mice presented reduced parasitemia and heart parasitism, no mortality, levels of pro-inflammatory mediators (TNF-α, CCL2, IL-6 and IFN-γ) similar to those found among naïve animals and no clinical manifestations of disease. On the other hand, CL Brener single infected mice presented higher parasitemia and heart parasitism, as well as an increased systemic release of pro-inflammatory mediators and higher mortality probably due to a toxic shock-like systemic inflammatory response. Interestingly, coinfection with JG and CL Brener strains resulted in intermediate parasitemia, heart parasitism and mortality. This was accompanied by an increase in the systemic release of IL-10 with a parallel increase in the number of MAC-3+ and CD4+ T spleen cells expressing IL-10. Therefore, the endogenous production of IL-10 elicited by coinfection seems to be crucial to counterregulate the potentially lethal effects triggered by systemic release of pro-inflammatory mediators induced by CL Brener single infection. In conclusion, our results suggest that the composition of the infecting parasite population plays a role in the host response to T. cruzi in determining the severity of the disease in experimentally infected BALB/c mice. The combination of JG and CL Brener was able to trigger both protective inflammatory immunity and regulatory immune mechanisms that attenuate damage caused by inflammation and disease severity in BALB/c mice

Study of the sensitisation process of a duplex stainless steel (UNS 1.4462) by means of confocal microscopy and localised electrochemical techniques

When duplex stainless steels are heated, they can become sensitised and intermetallic phases can appear. In this work, samples of duplex stainless steel, UNS 1.4462, have been heated (850 degrees C for 1 and 2 h) in a heating unit that can be accommodated to a confocal microscope in order to study the morphological changes in-situ. The electrochemical behaviour of the samples has been analysed by means of conventional and localised electrochemical techniques. According to the results, there is a general decrease in the steel resistance to localised corrosion; this decrease can be related to defects in the formed passive film.We wish to express our gratitude to MICINN (CTQ2009-07518), to Universitat Politecnica de Valencia (CEI-01-11), to the Generalitat Valenciana for its help in the CLSM acquisition (MY08/ISIRM/S/100), to Professor Alda Simoes and Andreia Marques for the help on LEIS measurements and to Dr. Asuncion Jaime for her translation assistance.Leiva García, R.; Fernandes, JS.; Muñoz-Portero, M.; Garcia-Anton, J. (2015). Study of the sensitisation process of a duplex stainless steel (UNS 1.4462) by means of confocal microscopy and localised electrochemical techniques. Corrosion Science. 94:327-341. https://doi.org/10.1016/j.corsci.2015.02.016S3273419