Event classification in MAGIC through Convolutional Neural Networks

The Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes are able to detect gamma rays from the ground with energies beyond several tens of GeV emitted by the most energetic known objects, including Pulsar Wind Nebulae, Active Galactic Nuclei, and Gamma-Ray Bursts. Gamma rays and cosmic rays are detected by imaging the Cherenkov light produced by the charged superluminal leptons in the extended air shower originated when the primary particle interacts with the atmosphere. These Cherenkov flashes brighten the night sky for short times in the nanosecond scale. From the image topology and other observables, gamma rays can be separated from the unwanted cosmic rays, and thereafter incoming direction and energy of the primary gamma rays can be reconstructed. The standard algorithm in MAGIC data analysis for the gamma/hadron separation is the so-called Random Forest, that works on a parametrization of the stereo events based on the shower image parameters. Until a few years ago, these algorithms were limited by the computational resources but modern devices, such as GPUs, make it possible to work efficiently on the pixel maps information. Most neural network applications in the field perform the training on Monte Carlo simulated data for the gamma-ray sample. This choice is prone to systematics arising from discrepancies between observational data and simulations. Instead, in this thesis I trained a known neural network scheme with observation data from a giant flare of the bright TeV blazar Mrk421 observed by MAGIC in 2013. With this method for gamma/hadron separation, the preliminary results compete with the standard MAGIC analysis based on Random Forest classification, which also shows the potential of this approach for further improvement. In this thesis first an introduction to the High-Energy Astrophysics and the Astroparticle physics is given. The cosmic messengers are briefly reviewed, with a focus on the photons, then astronomical sources of γ rays are described, followed by a description of the detection techniques. In the second chapter the MAGIC analysis pipeline starting from the low level data acquisition to the high level data is described. The MAGIC Instrument Response Functions are detailed. Finally, the most important astronomical sources used in the standard MAGIC analysis are listed. The third chapter is devoted to Deep Neural Network techniques, starting from an historical Artificial Intelligence excursus followed by a Machine Learning description. The basic principles behind an Artificial Neural Network and the Convolutional Neural Network used for this work are explained. Last chapter describes my original work, showing in detail the data selection/manipulation for training the Inception Resnet V2 Convolutional Neural Network and the preliminary results obtained from four test sources

MAGIC and H.E.S.S. detect VHE gamma rays from the blazar OT081 for the first time: a deep multiwavelength study

https://pos.sissa.it/395/815/pdfPublished versio

On the development of an instrument for in-line and real-time monitoring of blood-pH in extracorporeal-circulation

The possibility of real-time monitor critical care analytes such as pH is recognized to provide relevant information for the diagnosis and treatment of a variety of disorders and would be of considerable support for the management of extracorporeal circulation (ECC). However, despite blood pH can be measured from a long time by using electrodes or point-of-care instruments such as blood-gas analyzers, costs and complications associated with such measurement methods limit their use, thus blood pH is generally not monitored during routinary ECC. In this paper, we propose to exploit the tubing composing the ECC line to realize a low-cost and disposable pH-sensor and to interrogate such fluorescent sensor by using optical radiations. The proposed measuring system avoids complications related to blood sampling and may allow achieving single-patient cost requirements. Preliminary tests performed on a real ECC bloodline demonstrate that the system can operate with blood in ECC. Indeed, a 6 hours ECC treatment simulated using bovine blood revealed a deviation with respect to the reference pH-meter typically of about a few thousandths pH and with a maximum of about 0.01 pH

Infant communicative signals elicit differential brain dynamics in fathers and non-fathers

Responses to infant signals are critical to infant development and well-being. However, brain mechanisms underlying paternal responses to infant crying are still largely unknown. Here using EEG, we investigated brain activations in two different groups, 10 fathers and 10 non-fathers, in response to infant-related sounds: typically developing infants’ cry(TD), ASD infants’ cry(ASD), infants’ laughter(LAU), and white noise(WN). Event Related Potentials in the first second after stimuli onset were analyzed. Analysis revealed a significant interaction between group and stimulus type in the left dorsolateral frontal cluster of electrodes, a brain area involved in motor programming and communicative signals’ processing. A main effect of group in response to all auditory stimuli, irrespective of stimulus duration, emerged in the right temporal and parietal clusters. The different levels of familiarity and distinct processing strategies found in response to infant vocalizations shed light on the physiological mechanisms underlying adaptive paternal responses to infants’ behaviours.Accepted versio

Label-Free Optical Sensing and Medical Grade Resins: An Advanced Approach to Investigate Cell–Material Interaction and Biocompatibility

The Corning Epic® label-free (ELF) system is an innovative technology widely used in drug discovery, immunotherapy, G-protein-associated studies, and biocompatibility tests. Here, we challenge the use of ELF to further investigate the biocompatibility of resins used in manufacturing of blood filters, a category of medical devices representing life-saving therapies for the increasing number of patients with kidney failure. The biocompatibility assays were carried out by developing a cell model aimed at mimicking the clinical use of the blood filters and complementing the existing cytotoxicity assay requested by ISO10993-5. Experiments were performed by putting fibroblasts in both direct contact with two types of selected resins, and indirect contact by means of homemade customized well inserts that were precisely designed and developed for this technology. For both types of contact, fibroblasts were cultured in medium and human plasma. ELF tests confirmed the biocompatibility of both resins, highlighting a statistically significant different biological behavior of a polyaromatic resin compared to control and ion-exchanged resin, when materials were in indirect contact and soaking with plasma. Overall, the ELF test is able to mimic clinical scenarios and represents a promising approach to investigate biocompatibility, showing peculiar biological behaviors and suggesting the activation of specific intracellular pathways

Physiological responses of Siberian sturgeon (Acipenser baerii) juveniles fed on full-fat insect-based diet in an aquaponic system

Over the last years, the potential use of Black Soldier Fly meal (BSF) as a new and sustainable aquafeed ingredient has been largely explored in several fish species. However, only fragmentary information is available about the use of BSF meal-based diets in sturgeon nutrition. In consideration of a circular economy concept and a more sustainable aquaculture development, the present research represents the first comprehensive multidisciplinary study on the physiological effects of a BSF diet during sturgeon culture in an aquaponic system. Siberian sturgeon (Acipenser baerii) juveniles were fed over a 60-days feeding trial on a control diet (Hi0) and a diet containing 50% of full-fat BSF meal respect to fish meal (Hi50). Physiological responses of fish were investigated using several analytical approaches, such as gas chromatography-mass spectrometry, histology, Fourier Transformed Infrared Spectroscopy (FTIR), microbiome sequencing and Real-time PCR. While aquaponic systems performed optimally during the trial, Hi50 group fish showed lower diet acceptance that resulted in growth and survival reduction, a decrease in hepatic lipids and glycogen content (FTIR), a higher hepatic hsp70.1 gene expression and a worsening in gut histological morphometric parameters. The low feed acceptance showed by Hi50 group sturgeon highlighted the necessity to improve the palatability of BSF-based diet designed for sturgeon culture