Volcanoes muon imaging using Cherenkov telescopes

A detailed understanding of a volcano inner structure is one of the key-points for the volcanic hazards evaluation. To this aim, in the last decade, geophysical radiography techniques using cosmic muon particles have been proposed. By measuring the differential attenuation of the muon flux as a function of the amount of rock crossed along different directions, it is possible to determine the density distribution of the interior of a volcano. Up to now, a number of experiments have been based on the detection of the muon tracks crossing hodoscopes, made up of scintillators or nuclear emulsion planes. Using telescopes based on the atmospheric Cherenkov imaging technique, we propose a new approach to study the interior of volcanoes detecting the Cherenkov light produced by relativistic cosmic-ray muons that survive after crossing the volcano. The Cherenkov light produced along the muon path is imaged as a typical annular pattern containing all the essential information to reconstruct particle direction and energy. Our new approach offers the advantage of a negligible background and an improved spatial resolution. To test the feasibility of our new method, we have carried out simulations with a toy-model based on the geometrical parameters of ASTRI SST-2M, i.e. the imaging atmospheric Cherenkov telescope currently under installation onto the Etna volcano. Comparing the results of our simulations with previous experiments based on particle detectors, we gain at least a factor of 10 in sensitivity. The result of this study shows that we resolve an empty cylinder with a radius of about 100 m located inside a volcano in less than 4 days, which implies a limit on the magma velocity of 5 m/h.Comment: 21 pages, 21 figures, in press on Nuclear Inst. and Methods in Physics Research, A. Final version published online: 3-NOV-201

Effective pointing of the ASTRI-Horn telescope using the Cherenkov camera with the Variance method

Cherenkov telescope cameras are not suitable to perform astrometrical pointing calibration since they are not designed to produce images of the sky, but rather to detect nanosecond atmospheric flashes due to very high-energy cosmic radiation. Indeed, these instruments show only a moderate angular resolution (fractions of degrees) and are almost blind to the steady or slow-varying optical signal of starlight. For this reason, auxiliary optical instruments are typically adopted to calibrate the telescope pointing. However, secondary instruments are possible sources of systematic errors. Furthermore, the Cherenkov camera is the only one framing exactly the portion of the sky under study, and hence its exploitation for pointing calibration purposes would be desirable. In this contribution, we present a procedure to assess the pointing accuracy of the ASTRI-Horn telescope by means of its innovative Cherenkov camera. This instrument is endowed with a statistical method, the so-called Variance method, implemented in the logic board and able to provide images of the night sky background light as ancillary output. Taking into account the convolution between the optical point spread function and the pixel distribution, Variance images can be used to evaluate the position of stars with sub-pixel precision. In addition, the rotation of the field of view during observations can be exploited to verify the alignment of the Cherenkov camera with the optical axis of the telescope, with a precision of a few arcminutes, as upper limit. This information is essential to evaluate the effective pointing of the telescope, enhancing the scientific accuracy of the system.Comment: 7 pages, 5 figures, Proceedings of the 37th International Cosmic Ray Conference (ICRC 2021), Berlin, German

Use of the Peak-Detector mode for gain calibration of SiPM sensors with ASIC CITIROC read-out

The Cherenkov Imaging Telescope Integrated Read Out Chip (CITIROC) is a 32-channel fully analogue front-end ASIC dedicated to the read-out of silicon photo-multiplier (SiPM) sensors that can be used in a variety of experiments with different applications: nuclear physics, medical imaging, astrophysics, etc. It has been adopted as front-end for the focal plane detectors of the ASTRI-Horn Cherenkov telescope and, in this context, it was modified implementing the peak detector reading mode to satisfy the instrument requirements. For each channel, two parallel AC coupled voltage preamplifiers, one for the high gain and one for the low gain, ensure the read-out of the charge from 160 fC to 320 pC (i.e. from 1 to 2000 photo-electrons with SiPM gain = 10$^{6}$, with a photo-electron to noise ratio of 10). The signal in each of the two preamplifier chains is shaped and the maximum value is captured by activating the peak detector for an adjustable time interval. In this work, we illustrate the peak detector operation mode and, in particular, how this can be used to calibrate the SiPM gain without the need of external light sources. To demonstrate the validity of the method, we also present and discuss some laboratory measurements.Comment: 11 pages, 9 figures, 15th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD19) 14-17 October 2019 Siena, Italy (Submitted to JINST peer review on 05 January 2020

Nada que ver. Una obra de paisajes

Este trabajo pertenece al proyecto de investigación llamado“Envolvente sonora y la conexión con estadosemocionales en la formación y entrenamiento del actor”,llevado a cabo por docentes/investigadores dirigidos porel Dr. Juan Carlos Catalano, realizado en el Centro deInvestigaciones Dramáticas (CID) de la Facultad de Artede la U.N.C.P.B.A. El proyecto tiene una duración de unaño y pretende estudiar la relación entre el sonido y laemoción en la formación y entrenamiento expresivo deactores.Nos proponemos analizar la puesta en escena de la obrade teatro “Nada que ver”, dirigida por Marcela Juárez enel Club de Teatro de la ciudad de Tandil (Buenos Aires,Argentina). Se trata de una propuesta que se gesta a partirde una creación colectiva de tipo exploratoria en laque se suprime el sentido de la vista para dar paso a laelaboración de la vivencia en el público a través de lossentidos del oído, gusto, olfato y tacto. Analizamos enparticular el estímulo sonoro dentro la puesta en escenaen tanto sensación que se verifica a nivel psicofísico ysociocultural registrándose como fenómeno intrínsecamentesubjetivo, creador de sentido. El análisis se centraa partir de la indagación de los mapas sonoros presentesen la obra

“Nada que ver” y la construcción de sentido en primera persona

Este trabajo pertenece al proyecto de investigación llamado “Envolvente sonora y la conexión con estados emocionales en la formación y entrenamiento del actor”, llevado a cabo por docentes/investigadores dirigidos por el Dr. Juan Carlos Catalano, realizado en el Centro de Investigaciones Dramáticas (CID) de la Facultad de Arte de la U.N.C.P.B.A. El proyecto tiene una duración de un año y su objetivo principal es encontrar y definir los campos de construcción sonora (mapas sensoriales) dentro de un margen básico de predictibilidad para la posterior utilización en el marco de la indagación, la investigación y la creación artística, pretendiendo así estudiar la relación entre el sonido y la emoción en la formación y entrenamiento expresivo de actores. Nos proponemos analizar la puesta en escena de la obra de teatro “Nada que ver”, dirigida por Marcela Juárez en el Club de Teatro de la ciudad de Tandil (Buenos Aires, Argentina). Se trata de una propuesta que se gesta a partir de la creación colectiva de tipo exploratoria en la que se suprime el sentido de la vista para dar paso a la elaboración de la vivencia en el público a través de los sentidos del oído, el gusto, el olfato y el tacto. Por la cercanía con nuestro objeto de estudio analizaremos en particular la presencia del estímulo sonoro dentro la pieza, en tanto sensación que se verifica a nivel psicofísico y sociocultural registrándose como fenómeno intrínsecamente subjetivo, creador de sentido

Molecular Insights into the Local Anesthetic Receptor within Voltage-Gated Sodium Channels Using Hydroxylated Analogs of Mexiletine

We previously showed that the β-adrenoceptor modulators, clenbuterol and propranolol, directly blocked voltage-gated sodium channels, whereas salbutamol and nadolol did not (Desaphy et al., 2003), suggesting the presence of two hydroxyl groups on the aromatic moiety of the drugs as a molecular requisite for impeding sodium channel block. To verify such an hypothesis, we synthesized five new mexiletine analogs by adding one or two hydroxyl groups to the aryloxy moiety of the sodium channel blocker and tested these compounds on hNav1.4 channels expressed in HEK293 cells. Concentration–response relationships were constructed using 25-ms-long depolarizing pulses at −30 mV applied from an holding potential of −120 mV at 0.1 Hz (tonic block) and 10 Hz (use-dependent block) stimulation frequencies. The half-maximum inhibitory concentrations (IC50) were linearly correlated to drug lipophilicity: the less lipophilic the drug, minor was the block. The same compounds were also tested on F1586C and Y1593C hNav1.4 channel mutants, to gain further information on the molecular interactions of mexiletine with its receptor within the sodium channel pore. In particular, replacement of Phe1586 and Tyr1593 by non-aromatic cysteine residues may help in the understanding of the role of π–π or π–cation interactions in mexiletine binding. Alteration of tonic block suggests that the aryloxy moiety of mexiletine may interact either directly or indirectly with Phe1586 in the closed sodium channel to produce low-affinity binding block, and that this interaction depends on the electrostatic potential of the drug aromatic tail. Alteration of use-dependent block suggests that addition of hydroxyl groups to the aryloxy moiety may modify high-affinity binding of the drug amine terminal to Phe1586 through cooperativity between the two pharmacophores, this effect being mainly related to drug lipophilicity. Mutation of Tyr1593 further impaired such cooperativity. In conclusion, these results confirm our former hypothesis by showing that the presence of hydroxyl groups to the aryloxy moiety of mexiletine greatly reduced sodium channel block, and provide molecular insights into the intimate interaction of local anesthetics with their receptor