arXiv subjects

P. Oliva

Publications and source records attributed to P. Oliva.

At least 19 recordsLinked to original sources

arXiv2026

Compositional and morphological study of a Nuragic bronze figurine with neutron diffraction and neutron tomography

Nuragic figurines are rare and unique examples of the mastery achieved by Sardinian craftsmen in the early Iron Age. These bronze artefacts were most likely cast using the lost wax technique: the shapes were moulded with relative ease, and even complex figures could be represented. However, the manufacturing process was not always a single-step procedure: in some cases, the parts of the model were moulded separately and then assembled together. Therefore, the analytical study of Nuragic bronzes can help to understand the specific casting methods and to evaluate the techniques implemented by Sardinian craftsmen to produce such complex objects. In recent years, Time of Flight Neutron Diffraction (Tof-ND) and Neutron Imaging (NI) have proven to be among the most effective methods for non-invasive studies. Neutron diffraction and neutron imaging provide complementary quantitative and morphological information that can be the key to understanding the casting processes. In this work, the results of the analysis of a bronze figurine will be reported. The statuette represents a Nuragic warrior and was made available by the Soprintendenza Archeologia Belle Arti e Paesaggio per le province di Sassari e Nuoro (Sassari,Italy).

physics.app-ph↗

arXiv2019

A charming ICECUBE discover?

Last two years high energy neutrino data are studied. The two recent tau neutrino double bang candidate are discussed within their detectability, noise and expected rate. The neutrino flavor distribution mainly favoring equal electron and muon presence, is reminded. The angular distribution of highest muon neutrino tracks is analyzed. Their horizontal strong anisotropy and their remarkable up-down asymmetry, with the absence of clustering, is noticed. The main persistent missing of astrophysical X,gamma sources (as GRB and AGN flaring source) and all the above signatures led us to suggest a dominance of prompt charmed (atmospheric) events able to pollute, to smear and to hide any minor astronomical presence.

astro-ph.HE↗

arXiv2019

No guaranteed neutrino astronomy without (enough) double bang tau and downward HESE muon tracks: An update version

IceCube Neutrino Astronomy is considered. The tau neutrino flavor paucity and the asymmetry for the tracks suggest a dominant atmospheric charm noise. The correlated cascades and tracks asymmetry with relevant statistics enforce the charm noise dominance in the data. The charm signal may explain at once the absence of correlation for the tracks data with the galactic plane and with known brightest gamma sources.

astro-ph.HE↗

arXiv2017

Uncorrelated far AGN flaring with their delayed UHECRs events

The most distant AGN, within the allowed GZK cut-off radius, have been recently candidate by many authors as the best location for observed UHECR origination. Indeed, the apparent homogeneity and isotropy of recent UHECR signals seems to require a far cosmic isotropic and homogeneous scenario involving a proton UHECR courier: our galaxy or nearest local group or super galactic plane (ruled by Virgo cluster) are too much near and apparently too much anisotropic in disagreement with PAO and TA almost homogeneous sample data. However, the few and mild observed UHECR clustering, the North and South Hot Spots, are smeared in wide solid angles. Their consequent random walk flight from most far GZK UHECR sources, nearly at 100 Mpc, must be delayed (with respect to a straight AGN photon gamma flaring arrival trajectory) at least by a million years. During this time, the AGN jet blazing signal, its probable axis deflection (such as the helical jet in Mrk501), its miss alignment or even its almost certain exhaust activity may lead to a complete misleading correlation between present UHECR events and a much earlier active AGN ejection. UHECR maps maybe anyway related to galactic or nearest (Cen A, M82) AGN extragalactic UHECR sources shining in twin Hot Spot. Therefore we defend our (quite different) scenarios where UHECR are mostly made by lightest UHECR nuclei originated by nearby AGN sources, or few galactic sources, whose delayed signals reach us within few thousand years in the observed smeared sky areas.

astro-ph.HE↗

arXiv2017

2013-2016 review: HE Neutrino and UHECR Astronomy?

The last few years, 2013-2016, the high energy neutrino events in ICECUBE and the last rich UHECR maps by AUGER and TA were hopefully opening a new High Energy astronomy age. Unfortunately the foreseen correlation between neutrino with best gamma X sources has not (yet) been found. The most celebrated GRB gamma sources do not correlate to any neutrino events. The expected Local Group anisotropy in UHECR within the nuleon GZK cut off, has just fade away. UHECR events from Virgo are almost absent. Above two hundred TeV energy tau neutrino might shine by double bang in detectable way in ICECUBE. Within a dozen of events no tau neutrino arised (yet) in ICECUBE. Finally GRBs Fireball models calling since decades for HE neutrinos correlated imprint at TeVs energy are not (yet) found. So many absences are making a huge question mark: is there a new reading key?

astro-ph.HE↗

arXiv2016

Why not any tau double bang in Icecube, yet?

High Energy Neutrino Astronomy has been revealed by a sudden change in the flavor composition around maximal energies since three years of recording in ice km detector. However these discover didn' t led to any clear promised Neutrino Astronomy land yet. No correlation with hard gamma sources was found. Moreover the astrophysical spectra expected at Fermi value, seem to converge to a softer value, also required to avoid any Glashow resonant neutrino signal. We suggest a main solution within a composite flux ruled by prompt atmospheric neutrinos. Nevertheless the recent discover of twentyone crossing muons at hundreds TeVs had shown a first narrow overlapped doublet and a correlated track with a peculiar hard UHECR event clustering pointing to a well known microjet in bynary precession; these first connections hint for a non negligible astrophysical component making neutrino astronomy anyway already more than a hope.

astro-ph.HE↗

arXiv2014

Crossing muons in Icecube at highest energy: Cornerstone to neutrino astronomy

Highest energy neutrino events (contained) in cubic km ICECUBE detector resulted in last three years to be as many as $37-2=35$ signals (two of those having been recently discharged); these tens-hundred TeV (32 energetic events) up to rarest (only 3) PeV cascade showers, proved to have an extraterrestrial origin. The UHE neutrino flavor transition from a $ν_μ$ atmospheric dominance (over $ν_{e}$ showers at TeV energy), toward a higher energy shower cascade ($ν_{e}$, $ν_τ$) events at few tens TeV up to PeV energy is a hint of such a fast extraterrestrial injection. The majority (28 out of 35) of all these events are spherical cascade; their consequent smeared map is inconclusive. The additional rarest $9-2=7$ muon tracks, while being sharp in arrival directions, did not offer any correlated clustering nor any overlapping within known sources. We recently suggested that the highest energy (tens-TeV) crossing muon along the ICECUBE, mostly at horizons or upcoming, are the ideal tool able to reveal soon such clustering or even any narrow angle pointing to known (IR, X, Radio or $γ$) sources or self-correlation in rare doublet or triplet: a last hope for a meaningful and short-time $ν$ Astronomy. Any crossing muons clustering along galactic sources or within UHECR arrivals might also probe rarest UHECR event made by nuclei or neutrons. Within three years of ICECUBE data all the non-contained crossing highest energy muons above few tens TeV may be several dozens, possibly around $54$ (27 for upward ones), mostly enhanced along horizontal edges, painting known sources and/or self-correlating in doublets or rarest triplet (if steady or transient nearby source are at sight). Recent preliminary ICECUBE presentation on crossing muons are consistent with present preliminary muon rate estimate.

astro-ph.HE↗

arXiv2009

The XRF080109-SN2008D and a decade of GRB-Jet-SN connection

Last and nearest GRB-XRF 080109 has been an exceptional lesson on GRB nature. After a decade (since 25 April 08) we know that Supernovae may often contain a Jet. Its persistent activity may shine on axis as a GRBs. Such a persistent, thin beamed gamma jet may be powered by either a BH (Black Holes) or Pulsars. Late stages of these jets may loose the SN traces and appear as a short GRB or a long orphan GRB (depending on jet angular velocity and view angle). XRF are peripherical viewing of the jets. These precessing and spinning gamma jet are originated by Inverse Compton and-or Synchrotron Radiation at pulsars or micro-quasars sources, by ultra-relativistic electrons. These Jets are most powerful at Supernova birth, blazing, once on axis, to us and flashing GRB detector. The trembling of the thin jet explains naturally the observed erratic multi-explosive structure of different GRBs. The jets are precessing (by binary companion or inner disk asymmetry) and decaying by power on time scales of few hours, but they keep staying inside the observer cone view only a few seconds duration times (GRB); the jet is thinner in gamma and wider in X band. This explain the wider and longer X GRB afterglow duration and the rare presence of X-ray precursors.

astro-ph.HE↗

arXiv2007

Reflecting on Cherenkov reflections

Magic Telescope may observe and reveal at horizons lights from air-shower Cherenkov reflections. The ground, the sea, the cloudy sky (below the mountain) may reflect PeVs-EeV UHECR Cherenkov lights observable by MAGIC telescopes. Even rarest UHE neutrino skimming the atmosphere or skimming the Earth may induce upward-horizontal airshowers: a new Neutrino Astronomy. These fluorescence signals or the Cherenkov reflections in upper cloudy sky may flash in correlated BL-Lac or GRB shining at opposite edges. Geomagnetic splitting of Horizontal Air-showers may offer a new spectroscopy of UHECR from the knee up to GZK energy edges.

astro-ph↗

arXiv2007

Cherenkov Flashes and Fluorescence Flares on Telescopes: New lights on UHECR Spectroscopy while unveiling Neutrinos Astronomy

Cherenkov Telescopes (as Magic, Hess and Veritas), while pointing horizontally should reveal also the fluorescence flare tails of nearby down-going air-showers. Such air-showers, born at higher (tens km) altitudes, are growing and extending up to lowest atmospheres (EeVs) or up to higher (few km) quotas (PeVs). Viceversa, as it has been foreseen and only recently observed, the opposite takes place. Fluorescence Telescopes made for UHECR detection may be blazed by inclined Cherenkov lights. The geomagnetic splitting may tag the energy as well as the inclined shower footprint as seen in a recent peculiar event in AUGER. Additional stereoscopic detection may define the event origination distance and its consequent primary composition, extending our understanding on UHECR composition, while unveling a novel tau Neutrino Astronomy.

astro-ph↗

arXiv2007

Splitting neutrino masses and showering into Sky

Neutrino masses might be as light as a few time the atmospheric neutrino mass splitting. High Energy ZeV cosmic neutrinos (in Z-Showering model) might hit relic ones at each mass in different resonance energies in our nearby Universe. This non-degenerated density and energy must split UHE Z-boson secondaries (in Z-Burst model) leading to multi injection of UHECR nucleons within future extreme AUGER energy. Secondaries of Z-Burst as neutral gamma, below a few tens EeV are better surviving local GZK cut-off and they might explain recent Hires BL-Lac UHECR correlations at small angles. A different high energy resonance must lead to Glashow's anti-neutrino showers while hitting electrons in matter. In air, Glashow's anti-neutrino showers lead to collimated and directional air-showers offering a new Neutrino Astronomy. At greater energy around PeV, Tau escaping mountains and Earth and decaying in flight are effectively showering in air sky. These Horizontal showering is splitting by geomagnetic field in forked shapes. Such air-showers secondaries release amplified and beamed gamma bursts (like observed TGF), made also by muon and electron pair bundles, with their accompanying rich Cherenkov flashes. Also planet' s largest (Saturn, Jupiter) atmosphere limbs offer an ideal screen for UHE GZK and Z-burst tau neutrino, because their largest sizes. Titan thick atmosphere and small radius are optimal for discovering up-going resonant Glashow resonant showers. Earth detection of Neutrino showering by twin Magic Telescopes on top mountains, or by balloons and satellites arrays facing the limbs are the simplest and cheapest way toward UHE Neutrino Astronomy .

astro-ph↗

arXiv2006

Solving GRBs and SGRs puzzles by precessing Jets

A persistent, thin, micro-nano sr. beamed gamma jet, may be ejected from BH and Pulsars, powered by ultra-relativistic electron pairs. These jet while precessing and spinning are originated by Inverse Compton and-or Synchrotron Radiation at pulsars or micro-quasars sources. They are most powerful at Supernova birth, blazing, once on axis, to us and flashing GRB detector. The trembling of thin jets explains naturally the observed erratic multi-explosive structure of different GRBs. The jets are precessing and decaying on time scales of a few hours surviving as long as thousands of years, linking huge GRB-SN jet apparent Luminosity to more modest SGR relic Jets. Therefore long-life SGR may be repeating and if they are around our galaxy they might be observed again as the few known ones and a few rarer extragalactic XRFs. The orientation of the beam respect to the line of sight plays a key role in differentiating the wide GRB morphology. The relativistic cone is as small as the inverse of the electron progenitor Lorentz factor. The hardest and brightest gamma spectra are hidden inside the inner gamma jet axis. To observe the inner beamed GRB events one needs the widest SN sample and largest cosmic volumes. The most beamed are hardest.The nearest ones, within tens Mpc distances, are mostly observable on cone jet periphery leading to longest SN-GRB duration, with lowest fluency and the softest spectra, as in earliest GRB98425 and recent GRB 060218 signature. Conical shape of few nebulae describe in space the model signature. Recent X-ray precursor, like in GRB060124, ten minutes before the GRB event, or in SGR1806-20 two minutes before the main giant burst cannot be understood otherwise.

astro-ph↗

arXiv2006

Updated Z-Burst Neutrinos at Horizons

Recent homogeneous and isotropic maps of UHECR, suggest an isotropic cosmic origin almost uncorrelated to nearby Local Universe prescribed by GZK (tens Mpc) cut-off. Z-Burst model based on UHE neutrino resonant scattering on light relic ones in nearby Hot neutrino Dark Halo, may overcome the absence of such a local imprint and explain the recent correlation with BL Lac at distances of a few hundred Mpc. Z-Burst multiple imprint, due to very possible lightest non-degenerated neutrino masses, may inject energy and modulate UHECR ZeV edge spectra. The Z-burst (and GZK) ultra high energy neutrinos (ZeV and EeV band) may also shine, by UHE neutrinos mass state mixing, and rise in corresponding UHE Tau neutrino flavor, whose charged current tau production and its decay in flight, maybe the source of UHE showering on Earth. The Radius and the atmosphere size of our planet constrains the tau maximal distance and energy to make a shower. These terrestrial tau energies are near GZK energy limit. Higher distances and energies are available in bigger planets; eventual solar atmosphere horizons may amplify the UHE tau flight allowing tau showering at ZeV energies offering a novel way to reveal the expected Z-Burst extreme neutrino fluxes.

astro-ph↗

arXiv2006

UHE Cosmic Rays and Neutrinos Showering on Planet Edges

Ultra High Energy (UHE) Cosmic Rays, UHECR, may graze high altitude atmosphere leading to horizontal upward air-showers. Also PeVs electron antineutrino hitting electron in atmosphere may air-shower at W boson resonant mass. On the other side ultra high energy muon and electron neutrinos may also lead, by UHE neutrinos mass state mixing, to the rise of a corresponding UHE Tau neutrino flavor; the consequent UHE tau neutrinos, via charge current interactions in matter, may create UHE taus at horizons (Earth skimming neutrinos or Hor-taus) whose escape in atmosphere and whose consequent decay in flight, may be later amplified by upward showering on terrestrial, planetary atmospheres. Indeed because of the finite terrestrial radius, its thin atmosphere size its dense crust, the UHE tau cannot extend much more than 360 kilometers in air, corresponding to an energy of about 7.2 EeV, near but below GZK cut-off ones; on the contrary Jupiter (or even Saturn) may offer a wider, less dense and thicker gaseous layer at the horizons where Tau may loose little energy, travel longer before decay and rise and shower at 4-6 10^{19} eV or ZeV extreme energy. Titan atmosphere may open a rare window of opportunity for Up-ward Taus at PeVs. Also solar atmosphere may play a role, but unfortunately tau-showers secondaries maybe are too noisy to be disentangled, while Jupiter atmosphere, or better, Saturn one, may offer a clearer imprint for GZK (and higher Z-Burst) Tau showering, well below the horizons edges.

astro-ph↗

arXiv2005

Pre-processing methods for nodule detection in lung CT

The use of automatic systems in the analysis of medical images has proven to be very useful to radiologists, especially in the framework of screening programs, in which radiologists make their first diagnosis on the basis of images only, most of those corresponding to healthy patients, and have to distinguish pathological findings from non-pathological ones at an early stage. In particular, we are developing preprocessing methods to be applied for pulmonary nodule Computer Aided Detection in low-dose lung Multi Slice CT (Computed Tomography) images.

physics.med-ph↗

arXiv2004

CADe tools for early detection of breast cancer

A breast neoplasia is often marked by the presence of microcalcifications and massive lesions in the mammogram: hence the need for tools able to recognize such lesions at an early stage. Our collaboration, among italian physicists and radiologists, has built a large distributed database of digitized mammographic images and has developed a Computer Aided Detection (CADe) system for the automatic analysis of mammographic images and installed it in some Italian hospitals by a GRID connection. Regarding microcalcifications, in our CADe digital mammogram is divided into wide windows which are processed by a convolution filter; after a self-organizing map analyzes each window and produces 8 principal components which are used as input of a neural network (FFNN) able to classify the windows matched to a threshold. Regarding massive lesions we select all important maximum intensity position and define the ROI radius. From each ROI found we extract the parameters which are used as input in a FFNN to distinguish between pathological and non-pathological ROI. We present here a test of our CADe system, used as a second reader and a comparison with another (commercial) CADe system.

physics.med-ph↗

arXiv2004

GPCALMA: a Grid-based tool for Mammographic Screening

The next generation of High Energy Physics (HEP) experiments requires a GRID approach to a distributed computing system and the associated data management: the key concept is the Virtual Organisation (VO), a group of distributed users with a common goal and the will to share their resources. A similar approach is being applied to a group of Hospitals which joined the GPCALMA project (Grid Platform for Computer Assisted Library for MAmmography), which will allow common screening programs for early diagnosis of breast and, in the future, lung cancer. HEP techniques come into play in writing the application code, which makes use of neural networks for the image analysis and proved to be useful in improving the radiologists' performances in the diagnosis. GRID technologies allow remote image analysis and interactive online diagnosis, with a potential for a relevant reduction of the delays presently associated to screening programs. A prototype of the system, based on AliEn GRID Services, is already available, with a central Server running common services and several clients connecting to it. Mammograms can be acquired in any location; the related information required to select and access them at any time is stored in a common service called Data Catalogue, which can be queried by any client. The result of a query can be used as input for analysis algorithms, which are executed on nodes that are in general remote to the user (but always local to the input images) thanks to the PROOF facility. The selected approach avoids data transfers for all the images with a negative diagnosis (about 95% of the sample) and allows an almost real time diagnosis for the 5% of images with high cancer probability.

physics.med-ph↗

arXiv2004

GPCALMA: A Tool For Mammography With A GRID-Connected Distributed Database

The GPCALMA (Grid Platform for Computer Assisted Library for MAmmography) collaboration involves several departments of physics, INFN sections, and italian hospitals. The aim of this collaboration is developing a tool that can help radiologists in early detection of breast cancer. GPCALMA has built a large distributed database of digitised mammographic images (about 5500 images corresponding to 1650 patients) and developed a CAD (Computer Aided Detection) software which is integrated in a station that can also be used for acquire new images, as archive and to perform statistical analysis. The images are completely described: pathological ones have a consistent characterization with radiologist's diagnosis and histological data, non pathological ones correspond to patients with a follow up at least three years. The distributed database is realized throught the connection of all the hospitals and research centers in GRID tecnology. In each hospital local patients digital images are stored in the local database. Using GRID connection, GPCALMA will allow each node to work on distributed database data as well as local database data. Using its database the GPCALMA tools perform several analysis. A texture analysis, i.e. an automated classification on adipose, dense or glandular texture, can be provided by the system. GPCALMA software also allows classification of pathological features, in particular massive lesions analysis and microcalcification clusters analysis. The performance of the GPCALMA system will be presented in terms of the ROC (Receiver Operating Characteristic) curves. The results of GPCALMA system as "second reader" will also be presented.

physics.med-ph↗