450 research outputs found
Learning the Composition of Ultra High Energy Cosmic Rays
We apply statistical inference on the Pierre Auger Open Data to discern for
the first time the full mass composition of cosmic rays at different energies.
Working with longitudinal electromagnetic profiles of cosmic ray showers, in
particular their peaking depths , we employ central moments of the
distributions as features to discriminate between different
shower compositions. We find that already the first few moments entail the most
relevant information to infer the primary cosmic ray mass spectrum. Our
approach, based on an unbinned likelihood, allows us to consistently account
for sources of statistical uncertainties due to finite datasets, both measured
and simulated, as well as systematic effects. Finally, we provide a
quantitative comparison of different high energy hadronic interaction models
available in the atmospheric shower simulation codes.Comment: 28 pages + 16 page Appendix, 27 figure
Improving the Composition of Ultra High Energy Cosmic Rays with Ground Detector Data
We show that the maximum shower depth distributions of Ultra-High Energy
Cosmic Rays (UHECRs), as measured by fluorescence telescopes, can be augmented
by building a mapping to observables collected by surface detectors. The
resulting statistical improvement of such augmented dataset depends in a
universal way on the strength of the correlation exhibited by the mapping.
Building upon the publicly available data on "golden hybrid" events from the
Pierre Auger Observatory we project possible improvements in the inferred
composition of UHECRs for a range of possible mappings with varying correlation
strengths.Comment: 8 pages, 6 figures, method correcte
GPS time series at Campi Flegrei caldera (2000-2013)
The Campi Flegrei caldera is an active volcanic system associated to a high volcanic risk, and represents a well known and peculiar example of ground deformations (bradyseism), characterized by intense uplift periods, followed by subsidence phases with some episodic superimposed mini-uplifts. Ground deformation is an important volcanic precursor, and, its continuous monitoring, is one of the main tool for short time forecast
of eruptive activity. This paper provides an overview of the continuous GPS monitoring of the Campi Flegrei caldera from January 2000 to July 2013, including network operations, data recording and processing, and data products. In this period the GPS time series allowed continuous and accurate tracking of ground deformation of the area. Seven main
uplift episodes were detected, and during each uplift period, the recurrent horizontal displacement pattern, radial from the “caldera center”, suggests no significant change in deformation source geometry and location occurs. The complete archive of GPS time series at Campi Flegrei area is
reported in the Supplementary materials. These data can be usefull for the scientific community in improving the research on Campi Flegrei caldera dynamic and hazard assessment
Effect of layered double hydroxide intercalated with fluoride ions on the physical, biological and release properties of a dental composite resin
OBJECTIVES:
The aim of this work was the preparation of a new fluoride-releasing dental material characterized by a release of fluoride relatively constant over time without any initial toxic burst effect. This type of delivery is obtained by a matrix controlled elution and elicits the beneficial effect of a low amount of fluoride on human dental pulp stem cells (hDPSCs) towards mature phenotype.
METHODS:
The modified hydrotalcite intercalated with fluoride ions (LDH-F), used as filler, was prepared via ion exchange procedure and characterized by X-ray diffraction and FT-IR spectroscopy. The LDH-F inorganic particles (0.7, 5, 10, 20wt.%) were mixed with a photo-activated Bis-GMA/TEGDMA (45/55wt/wt) matrix and novel visible-light cured composites were prepared. The dynamic thermo-mechanical properties were determined by dynamic mechanical analyzer. The release of fluoride ions in physiological solution was determined using a ionometer. Total DNA content was measured by a PicoGreen dsDNA quantification kit to assess the proliferation rate of hDPSCs. Alkaline phosphatase activity (ALP) was measured in presence of fluoride resins.
RESULTS:
Incorporation of even small mass fractions (e.g. 0.7 and 5wt.%) of the fluoride LDH in Bis-GMA/TEGDMA dental resin significantly improved the mechanical properties of the pristine resin, in particular at 37°C. The observed reinforcement increases on increasing the filler concentration. The release of fluoride ions resulted very slow, lasting months. ALP activity gradually increased for 28 days in hDPSCs cell grown, demonstrating that low concentrations of fluoride contributed to the cell differentiation.
CONCLUSIONS:
The prepared composites containing different amount of hydrotalcite filler showed improved mechanical properties, slow fluoride release and promoted hDPSCs cell proliferation and cell differentiation
New Physics in CP Violating and Flavour Changing Quark Dipole Transitions
We explore CP-violating (CPV) effects of heavy New Physics in
flavour-changing quark dipole transitions, within the framework of Standard
Model Effective Field Theory (SMEFT). First, we establish the relevant
dimension six operators and consider the Renormalisation Group (RG) evolution
of the appropriate Wilson coefficients. We investigate RG-induced correlations
between different flavour-violating processes and electric dipole moments
(EDMs) within the Minimal Flavour Violating and quark flavour models.
At low energies, we set bounds on the Wilson coefficients of the dipole
operators using CPV induced contributions to observables in non-leptonic and
radiative , and decays as well as the neutron and electron EDMs.
This enables us to connect observable CPV effects at low energies and general
NP appearing at high scales. We present bounds on the Wilson coefficients of
the relevant SMEFT operators at the high scale , and
discuss most sensitive CPV observables for future experimental searches.Comment: 41 pages, 4 figures, 7 table
Characterization of GPS time series at the Neapolitan volcanic area by statistical analysis
The GPS time series recorded at the Neapolitan volcanic area reveals a very peculiar
behavior. When a clear deformation is observed, the amplitude distribution evolves from a
super‐Gaussian to a broader distribution. This behavior can be characterized by evaluating
the kurtosis. Spurious periodic components were evidenced by independent component
analysis and then removed by filtering the original signal. The time series for all stations was
modeled with a fifth‐order polynomial fit, which represents the deformation history at
that place. Indeed, when this polynomial is subtracted from the time series, the distributions
again become super‐Gaussian. A simulation of the deformation time evolution was
performed by superposing a Laplacian noise and a synthetic deformation history. The
kurtosis of the obtained signals decreases as the superposition increases, enlightening the
insurgence of the deformation. The presented approach represents a contribution aimed
at adding further information to the studies about the deformation at the Neapolitan volcanic
area by revealing geologically relevant data
Spatial and temporal distribution of vertical ground movements at Mt. Vesuvius in the period 1973-2009
Since the early ’70s vertical ground movements at Mount Vesuvius area have been investigated and monitored by the Osservatorio Vesuviano (Istituto Nazionale di Geofisica Vulcanologia - Osservatorio Vesuviano since 2001). This monitoring began with the installation of a high-precision
leveling line in the region at medium-high elevations on the volcano. The deformation pattern and expected strain field assessment methods in the volcanic structure induced by inner sources has demanded in subsequent
years the expansion of the leveling network up to cover the whole volcanic area, enclosing part of leveling lines of other institutions. As a result of this expansion, the Mt. Vesuvius Area Leveling Network (VALN) has today reached a length of about 270 km and consists of 359 benchmarks. It is configured in 21 circuits and is connected, westward, to the Campi Flegrei leveling network and, northward, to the Campania Plain leveling network. The data collected have been carefully re-analyzed for random
and systematic errors and for error propagation along the leveling lines to
identify the areas affected by significant ground movements. For each survey,
the data were rigorously adjusted and vertical ground movements were evaluated by differentiating the heights calculated by the various measurements conducted by the Osservatorio Vesuviano from 1973 to 2009
S.A.G.NET: Rete GPS dell'Appennino meridionale.
The Matese carbonatic massive occupies the northernmost part of the campanian Apennine while Sannio mounts, located to the East of massive, consists primarily of quaternary deposits and represent the area of Apennine chain degrading to East towards the Bradanica foredeep. The area was affected in historical time by several destructive earthquakes. The first ground deformation studies in this area started from 1990-2000 with the definition of geodetic networks, covering all or part of the massive Matese, with the aim of evaluating seismogenic sources responsible for the seismicity of the area. In 2002, a careful inspection of the existing GPS benchmarks was carried out; those which had a good state of preservation and a good level of reliability were included into a new geodetic Matese network, consisting of 38 3D benchmarks. Several surveys were conducted in 2000, 2002 and 2004,with the aim of defining the strain field, defined by plano-altimetric components. In 2005, an intensive work of gathering and validating available data started, integrating data collected by previous surveys with those collected during the new survey carried out in 2006. This work describes in detail the various stages of implementing the final network S.A.G.NET, whose geometry was also bound to the distribution of the known seismogenic sources present in the area. We also show the first results obtained from data collected from2000 to 2006 and the resulting kinematic model for this area
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