Graph neural network for track reconstruction in space experiments

Development of tracking algorithm with deep learning techniques A range of models inspired by computer vision applications were investigated, which operated on data from tracking detectors in a format resembling images [A deep learning method for the trajectory reconstruction of cosmic rays with the DAMPE mission, Andrii Tykhonov et al,Astroparticle Physics 146, April 2023, 102795 102795]. Although these approaches demonstrated potential, image-based methods encountered difficulties in adapting to the scale of realistic data, primarily due to the high dimensionality and sparsity of the data. Tracking data are naturally represented as graph by identifying hits as nodes and tracks segments as (in general) directed edges. So that, we have explored the use of geometric deep learning techniques. Specifically, we have developed an algorithm that leverages the Graph Neural Network approach, which is a subset of geometric deep learning. This approach has been applied to the task of track reconstruction in a simplified model of space experiments. The details of our toy model simulations, the algorithm's development process, and the preliminary results are described in the accompanying slides

Small interfering RNAs in tendon homeostasis.

Background: Tenogenesis and tendon homeostasis are guided by genes encoding for the structural molecules of tendon fibres. Small interfering RNAs (siRNAs), acting on gene regulation, can therefore participate in the process of tendon healing.Sources of data: A systematic search of different databases to October 2020 identified 17 suitable studies.Areas of agreement: SiRNAs can be useful to study reparative processes of tendons and identify possible therapeutic targets in tendon healing.Areas of controversy: Many genes and growth factors involved in the processes of tendinopathy and tendon healing can be regulated by siRNAs. It is however unclear which gene silencing determines the expected effect.Growing points: Gene dysregulation of growth factors and tendon structural proteins can be influenced by siRNA.Areas timely for developing research: It is not clear whether there is a direct action of the siRNAs that can be used to facilitate the repair processes of tendons

Melatonin and adolescent idiopathic scoliosis: The present evidence

Adolescent idiopathic scoliosis (AIS) is a multifactorial condition with genetic predisposing factors, and several causes have been put forward for its aetiopathogenesis, including possible hormonal dysfunction. Melatonin seems to play significant role in AIS

Gli "ASTRI" di Horn: l'astronomo che ha progettato il futuro

Guido Horn d’Arturo (Trieste 1879-Bologna 1967), ebreo triestino, fu direttore dell’Osservatorio universitario di Bologna per un trentennio, interrotto solo dalle leggi razziali. Questa mostra, nata nel 2017 in occasione del cinquantesimo anniversario della sua morte, lo ricorda come scienziato geniale, pioniere della divulgazione scientifica, personaggio eclettico, patriota e viene oggi riproposta, riveduta e ampliata, in occasione della dedica a Guido Horn d’Arturo del telescopio ASTRI (Astrofisica con Specchi a Tecnologia Replicante), operativo a Serra La Nave e parte di un più grande progetto, Cherenkov Telescope Array, CTA, che, tra l’altro, ha i propri uffici a Bologna. Anche ASTRI, infatti, come i moderni grandi telescopi, tra i quali l’European Extremely Large Telescope dell’ESO -39 m con 798 tasselli- che sarà operativo in Cile nel 2024, e nello spazio il James Webb Space Telescope della Nasa -6,5 m con 18 tasselli- il cui lancio è previsto nel 2021, è l’erede di una metodologia del tutto nuova di costruzione e aggiustamento degli specchi dei telescopi: “lo specchio a tasselli” di Guido Horn d’Arturo. Ideato negli anni Trenta e costruito effettivamente solo negli anni Cinquanta, il prototipo, di 1,8 m di diametro complessivi e composto di 61 tasselli esagonali, rivoluzionò radicalmente lo sviluppo della moderna astronomia osservativa. La collocazione di ASTRI nel territorio di Catania, motivo di grande soddisfazione per l’intera città, è stata di incentivo a celebrare questa illustre figura anche attraverso la riedizione della mostra bolognese all’interno del Monastero dei Benedettini, antica sede dell’Osservatorio di Catania, luogo in cui avvennero gli esordi della carriera scientifica di Horn D’Arturo e in cui lo scienziato avrebbe tanto desiderato ritornare

Gleam: the GLAST Large Area Telescope Simulation Framework

This paper presents the simulation of the GLAST high energy gamma-ray telescope. The simulation package, written in C++, is based on the Geant4 toolkit, and it is integrated into a general framework used to process events. A detailed simulation of the electronic signals inside Silicon detectors has been provided and it is used for the particle tracking, which is handled by a dedicated software. A unique repository for the geometrical description of the detector has been realized using the XML language and a C++ library to access this information has been designed and implemented.Comment: 10 pages, Late

Notulae to the Italian native vascular flora: 5.

In this contribution, new data concerning the distribution of native vascular flora in Italy are presented. It includes new records and confirmations to the Italian administrative regions for taxa in the genera Allium, Arabis, Campanula, Centaurea, Chaerophyllum, Crocus, Dactylis, Dianthus, Festuca, Galanthus, Helianthemum, Lysimachia, Milium, Pteris, and Quercus. Nomenclature and distribution updates, published elsewhere, and corrections are provided as supplementary material

A population of gamma-ray emitting globular clusters seen with the Fermi Large Area Telescope

Globular clusters with their large populations of millisecond pulsars (MSPs) are believed to be potential emitters of high-energy gamma-ray emission. Our goal is to constrain the millisecond pulsar populations in globular clusters from analysis of gamma-ray observations. We use 546 days of continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope to study the gamma-ray emission towards 13 globular clusters. Steady point-like high-energy gamma-ray emission has been significantly detected towards 8 globular clusters. Five of them (47 Tucanae, Omega Cen, NGC 6388, Terzan 5, and M 28) show hard spectral power indices $(0.7 < \Gamma <1.4)$ and clear evidence for an exponential cut-off in the range 1.0-2.6 GeV, which is the characteristic signature of magnetospheric emission from MSPs. Three of them (M 62, NGC 6440 and NGC 6652) also show hard spectral indices $(1.0 < \Gamma < 1.7)$, however the presence of an exponential cut-off can not be unambiguously established. Three of them (Omega Cen, NGC 6388, NGC 6652) have no known radio or X-ray MSPs yet still exhibit MSP spectral properties. From the observed gamma-ray luminosities, we estimate the total number of MSPs that is expected to be present in these globular clusters. We show that our estimates of the MSP population correlate with the stellar encounter rate and we estimate 2600-4700 MSPs in Galactic globular clusters, commensurate with previous estimates. The observation of high-energy gamma-ray emission from a globular cluster thus provides a reliable independent method to assess their millisecond pulsar populations that can be used to make constraints on the original neutron star X-ray binary population, essential for understanding the importance of binary systems in slowing the inevitable core collapse of globular clusters.Comment: Accepted for publication in A&A. Corresponding authors: J. Kn\"odlseder, N. Webb, B. Pancraz

Vaccines against toxoplasma gondii : challenges and opportunities

Development of vaccines against Toxoplasma gondii infection in humans is of high priority, given the high burden of disease in some areas of the world like South America, and the lack of effective drugs with few adverse effects. Rodent models have been used in research on vaccines against T. gondii over the past decades. However, regardless of the vaccine construct, the vaccines have not been able to induce protective immunity when the organism is challenged with T. gondii, either directly or via a vector. Only a few live, attenuated T. gondii strains used for immunization have been able to confer protective immunity, which is measured by a lack of tissue cysts after challenge. Furthermore, challenge with low virulence strains, especially strains with genotype II, will probably be insufficient to provide protection against the more virulent T. gondii strains, such as those with genotypes I or II, or those genotypes from South America not belonging to genotype I, II or III. Future studies should use animal models besides rodents, and challenges should be performed with at least one genotype II T. gondii and one of the more virulent genotypes. Endpoints like maternal-foetal transmission and prevention of eye disease are important in addition to the traditional endpoint of survival or reduction in numbers of brain cysts after challenge

Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye