1. The second knee in the cosmic ray spectrum observed with the surface detector of the Pierre Auger ObservatoryGabriel Brichetto Orquera, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci Opis: The determination of the energy spectrum features with low systematic uncertainty is crucial for interpreting the nature of cosmic rays. In this study, we conducted a measurement of the energy spectrum at the Pierre Auger Observatory using a surface detector with a calorimetric
energy scale indirectly set by a fluorescence detector. The surface detector consists of an array of water-Cherenkov detectors that extends over 3000 km^2 with 1500m spacing. Additionally,
two nested arrays of the same kind with 750m and 433m spacing were utilized to lower the energy threshold of the measurements. This contribution presents, for the first time, the spectrum measured with the 433m array, which reduces the energy threshold down to 63 PeV, nearly half the energy at which we previously published a steepening using the 750m array. Our measurements include a characterization of the spectral features of the flux steepening around 230 PeV, known
as the second-knee. The study benefits from a nearly 100% duty cycle and geometrical exposure. Notably, this is the first simultaneous measurement of the second knee energy and spectral indexes before and after the break, using a surface detector with an energy scale predominantly independent of air shower simulations and assumptions regarding hadronic interaction models. Ključne besede: ultra-high energy cosmic rays, Pierre Auger Observatory, hadronic interaction model, water-Cherenkov detectors Objavljeno v RUNG: 23.01.2024; Ogledov: 398; Prenosov: 4 Celotno besedilo (1,48 MB) Gradivo ima več datotek! Več... |
2. Measurement of the Proton-Air Cross Section with Telescope Arrays Black Rock, Long Ridge, and Surface Array in Hybrid Mode.R. Abbasi, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci Opis: Ultra High Energy Cosmic Ray (UHECR) detectors have been reporting on the proton-air cross section measurement beyond the capability of particle accelerators since 1984. The knowledge of this fundamental particle property is vital for our understanding of high energy particle interactions and could possibly hold the key to new physics. The data used in this work was collected over eight years using the hybrid events of Black Rock (BR) and Long Ridge (LR) fluorescence detectors as well as the Telescope Array Surface Detector (TASD). The proton-air cross section is determined at s√=73~TeV by fitting the exponential tail of the Xmax distribution of these events. The proton-air cross section is then inferred from the exponential tail fit and from the most updated high energy interaction models. σ^inel_p−air is observed to be 520.1±35.8 [Stat.] +25.3−42.9 [Sys.] mb. This is the second proton-air cross section work reported by the Telescope Array collaboration. Ključne besede: Telescope Array, indirect detection, hybrid detection, ground array, fluorescence detection, ultra-high energy, cosmic rays, Xmax, proton-air cross-section, high energy particle interaction Objavljeno v RUNG: 04.10.2023; Ogledov: 728; Prenosov: 4 Celotno besedilo (1,47 MB) Gradivo ima več datotek! Več... |
3. Measurement of the fluctuations in the number of muons in extensive air showers with the Pierre Auger ObservatoryA. Aab, Andrej Filipčič, Gašper Kukec Mezek, Jon Paul Lundquist, Samo Stanič, Marta Trini, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2021, izvirni znanstveni članek Ključne besede: ultra-high energy cosmic rays, extensive air showers (EAS), EAS muonic component, hadronic interaction models, Pierre Auger Observatory Objavljeno v RUNG: 29.04.2021; Ogledov: 2223; Prenosov: 0 Gradivo ima več datotek! Več... |
4. podMAST / Jenny Brockmann : Leaving the audience unsatisfied through unstable systems, to create communication about urgent questions in societyPeter Purg, Lange Teena, radijska ali televizijska oddaja, podkast, intervju, novinarska konferenca Ključne besede: Experiment, inbetween, balance, architecture, speculative, transdisciplinary, embodiment, knowledge sharing, conversation, unsatisfied audience, process based, shaping interaction spaces, encounter, care, integrity., inbetween, balance, architecture, speculative, transdisciplinary, embodiment, knowledge sharing, conversation, unsatisfied audience, process based, shaping interaction spaces, encounter, care, integrity. Objavljeno v RUNG: 06.11.2020; Ogledov: 2434; Prenosov: 71 Povezava na celotno besedilo Gradivo ima več datotek! Več... |
5. Structural and functional determinants of TDP-43 aggregation : DissertationSanja Škaro, 2019, doktorska disertacija Opis: TDP-43 (TAR DNA-binding protein) is an hnRNP that was identified as the main component of the brain inclusions characteristically found in patients suffering of Amyotrophic Lateral Sclerosis and Frontotemporal Lobar Degeneration. As an hnRNP protein, TDP-43 fulfills diverse roles in mRNA metabolism, localization and transport. Structurally, TDP-43 is composed of a well conserved N terminal domain (NTD), two RRM domains of which RRM1 is necessary for recognizing and binding to its target, UG rich RNA sequences, and the C-terminal domain (CTD) which is a Glycine rich domain. The CTD also contains a Q/N rich region that plays a key role in protein aggregation and interaction with another hnRNP proteins and polyglutamine repeats. This thesis focus on the structural determinants involved in the different TDP-43 interactions with itself and with other hnRNPs. Both the carboxyl and amino terminal domains are involved in these interactions. We have mapped the regions more relevant for the function of TDP-43 and for the aggregation process characteristic of the pathological pathway leading to neurodegeneration. We have started to further study the N-terminal domain. Previous results in our laboratory using a cellular aggregation model have shown that the N-terminal domain is also necessary for sequestering the endogenous TDP-43 into the aggregates. In particular, the intact NTD, specifically residues 1 to 77, have been shown to be needed to efficiently recruit TDP-43 monomers into these aggregates. We have extended our knowledge of NTD structure and function, by assessing the behavior of a series of proteins in which key structural features (α-helix and β-sheets) were modified and TDP-43 splicing function together with structure via NMR were analyzed. It was found that by disrupting protein secondary structure in the NTD (mutation in α-helix NTD-31V/R-32T/R) the capacity of the aggregates to sequester enough TDP-43 to induce loss of function was lost.In fact, this protein is also unable to recovery TDP-43 functionality when it is disrupted due to sequestration of the endogenous TDP-43 in add back experiments. Disturbing protein stability through substitution of residues in α-helix also affects its ability to form an active conformation. On the other hand, synthesis of hybrid peptides containing certain NTD and CTD segments was performed in order to see if they are capable to bind to the TDP-43 aggregates. However, it has been shown that these synthetic peptides have a greater ability to induce TDP-43 aggregation than to bind to them, probably due to specific functional characteristics of NTD and CTD segments used for their synthesis.The main focus of the thesis was on the C-terminal domain sequences involved in protein-protein interaction, misfolding and aggregation.A comparison of human, mouse, zebrafish, Annelida, flatworms and Drosophila showed a very strong conservation of the NTD and RRMs, but the C terminal regions of human and other TDP-43 orthologues are very different.I have studied Human and Drosophila melanogaster orthologues, because Drosophila orthologue contains different paralogs of TDP-43.Through a series of deletions and mutations it was shown that the shorter paralog of Drosophila TDP-43 (TBPH-RA) is more active than the longer one (TBPH-RC), and that this is due to a combination of two factors: 1. TBPH-RC by itself aggregates more than TBPH-RA, 2. The functionality of TBPH-RC is downregulated by intramolecular interactions in the C terminal domain. Apparently there is a cation-π interaction involving Tryptophan and Arginine in TBPH-RC that has a high relevance to the protein function and is lacking in the TBPH-RA.Overall this data has identified structural features essential for the proper function of TDP-43.In addition, we have also identified sequences that are critical in the pathological aggregation process of TDP-43 that lead to the characteristic brain inclusions in ALS and FTLD and to the loss of functionality Ključne besede: TDP-43 structural determinants, hybrid peptides, protein-protein interactions, intramolecular interaction, cation-π interaction, Drosophila orthologues. Objavljeno v RUNG: 22.07.2019; Ogledov: 3358; Prenosov: 190 Celotno besedilo (6,84 MB) |
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7. Shower universality reconstruction of data from the Pierre Auger Observatory and validations with hadronic interaction modelsAriel Bridgeman, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2017, objavljeni znanstveni prispevek na konferenci Ključne besede: Pierre Auger Observatory, shower universality reconstruction, hadronic interaction models Objavljeno v RUNG: 16.02.2018; Ogledov: 3379; Prenosov: 150 Celotno besedilo (1,60 MB) |
8. Report from the Multi-Messenger Working Group at UHECR-2014 ConferenceTimo Karg, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2016, objavljeni znanstveni prispevek na konferenci Ključne besede: ultra-high energy cosmic rays (UHECR), UHECR interaction products, multi-messenger studies, neutron, neutrino, photon, IceCube neutrino observatory, Pierre Auger Observatory, Telescope Array Objavljeno v RUNG: 17.11.2016; Ogledov: 4489; Prenosov: 0 Gradivo ima več datotek! Več... |
9. Extension of the measurement of the proton-air cross section with the Pierre Auger ObservatoryRalf Ulrich, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, objavljeni znanstveni prispevek na konferenci Opis: With hybrid data of the Pierre Auger Observatory it is possible
to measure the cross section of proton-air collisions at
energies far beyond the reach of the LHC. Since the first
measurement by the Pierre Auger Collaboration the event
statistics has increased significantly. The proton-air
cross section is now estimated in the two energy intervals in
lg(E/eV) from 17.8 to 18 and from 18 to 18.5. These energies
are chosen so that they maximise the available event statistics
and at the same time lie in the region most compatible with a
significant primary proton fraction. Of these data, only the
20% of most proton-like events are considered for the
measurement. Furthermore, with a new generation of hadronic
interaction models which have been tuned to LHC data, the
model-dependent uncertainties of the measurement are re-visited. Ključne besede: Pierre Auger Observatory, extensive air showers, proton-air cross section, hadronic interaction models Objavljeno v RUNG: 03.03.2016; Ogledov: 4563; Prenosov: 196 Celotno besedilo (114,02 KB) |
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