759 research outputs found
Knowledge Driven Behavioural Analysis in Process Intelligence
InthispaperweillustratehowtheknowledgedrivenBehaviourAnal- ysis, which has been used in the KITE.it process management framework, can support the evolution of analytics from descriptive to predictive. We describe how the methodology uses an iterative three-step process: first the descriptive knowledge is collected, querying the knowledge base, then the prescriptive and predictive knowledge phases allow us to evaluate business rules and objectives, extract unexpected business patterns, and screen exceptions. The procedure is iterative since this novel knowledge drives the definition of new descriptive an- alytics that can be combined with business rules and objectives to increase our level of knowledge on the combination between process behaviour and contex- tual information
First Measurement of the He3+He3-->He4+2p Cross Section down to the Lower Edge of the Solar Gamow Peak
We give the LUNA results on the cross section measurement of a key reaction
of the proton-proton chain strongly affecting the calculated neutrino
luminosity from the Sun: He3+He3-->He4+2p. Due to the cosmic ray suppression
provided by the Gran Sasso underground laboratory it has been possible to
measure the cross section down to the lower edge of the solar Gamow peak, i.e.
as low as 16.5 keV centre of mass energy. The data clearly show the cross
section increase due to the electron screening effect but they do not exhibit
any evidence for a narrow resonance suggested to explain the observed solar
neutrino flux.Comment: 5 pages, RevTeX, and 2 figures in PostScript Submitted for
publicatio
Solar neutrino detection in a large volume double-phase liquid argon experiment
Precision measurements of solar neutrinos emitted by specific nuclear
reaction chains in the Sun are of great interest for developing an improved
understanding of star formation and evolution. Given the expected neutrino
fluxes and known detection reactions, such measurements require detectors
capable of collecting neutrino-electron scattering data in exposures on the
order of 1 ktonne yr, with good energy resolution and extremely low background.
Two-phase liquid argon time projection chambers (LAr TPCs) are under
development for direct Dark Matter WIMP searches, which possess very large
sensitive mass, high scintillation light yield, good energy resolution, and
good spatial resolution in all three cartesian directions. While enabling Dark
Matter searches with sensitivity extending to the "neutrino floor" (given by
the rate of nuclear recoil events from solar neutrino coherent scattering),
such detectors could also enable precision measurements of solar neutrino
fluxes using the neutrino-electron elastic scattering events. Modeling results
are presented for the cosmogenic and radiogenic backgrounds affecting solar
neutrino detection in a 300 tonne (100 tonne fiducial) LAr TPC operating at
LNGS depth (3,800 meters of water equivalent). The results show that such a
detector could measure the CNO neutrino rate with ~15% precision, and
significantly improve the precision of the 7Be and pep neutrino rates compared
to the currently available results from the Borexino organic liquid
scintillator detector.Comment: 21 pages, 7 figures, 6 table
Mediterranean Sea large-scale low-frequency ocean variability and water mass formation rates from 1987 to 2007: A retrospective analysis
We describe a synthesis of the Mediterranean Sea circulation structure and dynamics from a 23-year- long reanalysis of the ocean circulation carried out by Adani et al. (2011). This mesoscale permitting dynamical reconstruction of past ocean variability in the Mediterranean Sea allows the study of the time-mean circulation and its low frequency, decadal, components. It is found that the time-mean circu- lation is composed of boundary and open ocean intensified jets at the border of cyclonic and anticyclonic gyres. The large scale basin circulation is generally characterized in the northern regions by cyclonic gyres and in its southern parts by anticyclonic gyres and eddy-dominated flow fields, with the exception of the Tyrrhenian and the northern Ionian Sea. The time-mean Tyrrhenian Sea circulation is dominated by cyclonic gyres of different intensity and intermittency. The northern Ionian Sea circulation, however, reverses in sign in two ten-year periods, the first in 1987–1996 and the second in 1997–2006, which is here called the Northern Ionian reversal phenomenon. This reversal is provoked by the excursion of the Atlantic-Ionian Stream from the middle to the northern parts of the basin. The decadal variability of other parts of the basin is characterized by changes in strength of the basin scale structures. The water mass formation rates and variability are dominated by event-like periods where the intermediate and deep waters are formed for 2–3 years at higher rates. The largest deep water formation events of the past 23 years occurred separately in the western and eastern Mediterranean basin: the first coincided with the Eastern Mediterranean Transient (Roether et al., 1996) and the second with the western Mediterranean deep water formation event in 2005–2006 (Smith et al., 2008). A new schematic of the basin-scale circu- lation is formulated and commented.Published318-3324A. Oceanografia e climaJCR Journa
R&D project for neutrinoless double beta decay in Borexino
Since the proposal of the Borexino project in the early nineties, the idea to perform a neutrinoless double beta decay experiment with 136Xe dissolved in the scintillator was considered. The beautiful results obtained by the Borexino experiment, which achieved a purity far exceeding design goals, and a new concept for dissolving large quantities of xenon in the scintillator by increasing its pressure make this possibility even more interesting for a new-generation experiment in the next decade. We present the ongoing R&D studies to look for neutrinoless double
beta decay using liquid scintillators, discussing the optical properties of the Borexino scintillator when xenon is dissolved in large quantity and with high pressure
AEGIS at CERN: Measuring Antihydrogen Fall
The main goal of the AEGIS experiment at the CERN Antiproton Decelerator is
the test of fundamental laws such as the Weak Equivalence Principle (WEP) and
CPT symmetry. In the first phase of AEGIS, a beam of antihydrogen will be
formed whose fall in the gravitational field is measured in a Moire'
deflectometer; this will constitute the first test of the WEP with antimatter.Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, June 28-July 2, 201
Annihilation of low energy antiprotons in silicon
The goal of the AEIS experiment at the Antiproton
Decelerator (AD) at CERN, is to measure directly the Earth's gravitational
acceleration on antimatter. To achieve this goal, the AEIS
collaboration will produce a pulsed, cold (100 mK) antihydrogen beam with a
velocity of a few 100 m/s and measure the magnitude of the vertical deflection
of the beam from a straight path. The final position of the falling
antihydrogen will be detected by a position sensitive detector. This detector
will consist of an active silicon part, where the annihilations take place,
followed by an emulsion part. Together, they allow to achieve 1 precision on
the measurement of with about 600 reconstructed and time tagged
annihilations.
We present here, to the best of our knowledge, the first direct measurement
of antiproton annihilation in a segmented silicon sensor, the first step
towards designing a position sensitive silicon detector for the
AEIS experiment. We also present a first comparison with
Monte Carlo simulations (GEANT4) for antiproton energies below 5 MeVComment: 21 pages in total, 29 figures, 3 table
The Cross Section of 3He(3He,2p)4He measured at Solar Energies
We report on the results of the \hethet\ experiment at the underground
accelerator facility LUNA (Gran Sasso). For the first time the lowest
projectile energies utilized for the cross section measurement correspond to
energies below the center of the solar Gamow peak (=22 keV). The
data provide no evidence for the existence of a hypothetical resonance in the
energy range investigated. Although no extrapolation is needed anymore (except
for energies at the low-energy tail of the Gamow peak), the data must be
corrected for the effects of electron screening, clearly observed the first
time for the \hethet\ reaction. The effects are however larger than expected
and not understood, leading presently to the largest uncertainty on the quoted
value for bare nuclides (=5.40 MeV b).Comment: 18 pages, 10 postscript figures, Calculations concerning hypothetical
resonanz added, Submitted to Phys. Rev. C., available at this URL:
HTTP://www.lngs.infn.it/lngs/htexts/luna/luna.htm
Prospects for measuring the gravitational free-fall of antihydrogen with emulsion detectors
The main goal of the AEgIS experiment at CERN is to test the weak equivalence
principle for antimatter. AEgIS will measure the free-fall of an antihydrogen
beam traversing a moir\'e deflectometer. The goal is to determine the
gravitational acceleration g for antihydrogen with an initial relative accuracy
of 1% by using an emulsion detector combined with a silicon micro-strip
detector to measure the time of flight. Nuclear emulsions can measure the
annihilation vertex of antihydrogen atoms with a precision of about 1 - 2
microns r.m.s. We present here results for emulsion detectors operated in
vacuum using low energy antiprotons from the CERN antiproton decelerator. We
compare with Monte Carlo simulations, and discuss the impact on the AEgIS
project.Comment: 20 pages, 16 figures, 3 table
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Solar neutrino with Borexino: results and perspectives
Borexino is a unique detector able to perform measurement of solar neutrinos
fluxes in the energy region around 1 MeV or below due to its low level of
radioactive background. It was constructed at the LNGS underground laboratory
with a goal of solar Be neutrino flux measurement with 5\% precision. The
goal has been successfully achieved marking the end of the first stage of the
experiment. A number of other important measurements of solar neutrino fluxes
have been performed during the first stage. Recently the collaboration
conducted successful liquid scintillator repurification campaign aiming to
reduce main contaminants in the sub-MeV energy range. With the new levels of
radiopurity Borexino can improve existing and challenge a number of new
measurements including: improvement of the results on the Solar and terrestrial
neutrino fluxes measurements; measurement of pp and CNO solar neutrino fluxes;
search for non-standard interactions of neutrino; study of the neutrino
oscillations on the short baseline with an artificial neutrino source (search
for sterile neutrino) in context of SOX project.Comment: 15 pages, 4 figure
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