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Primate-specific Evolution of an LDLR Enhancer
Background: Sequence changes in regulatory regions have often been invoked to explain phenotypic divergence among species, but molecular examples of this have been difficult to obtain. Results: In this study we identified an anthropoid primate-specific sequence element that contributed to the regulatory evolution of the low-density lipoprotein receptor. Using a combination of close and distant species genomic sequence comparisons coupled with in vivo and in vitro studies, we found that a functional cholesterol-sensing sequence motif arose and was fixed within a pre-existing enhancer in the common ancestor of anthropoid primates. Conclusion: Our study demonstrates one molecular mechanism by which ancestral mammalian regulatory elements can evolve to perform new functions in the primate lineage leading to human
Demonstration and Comparison of Operation of Photomultiplier Tubes at Liquid Argon Temperature
Liquified noble gases are widely used as a target in direct Dark Matter
searches. Signals from scintillation in the liquid, following energy deposition
from the recoil nuclei scattered by Dark Matter particles (e.g. WIMPs), should
be recorded down to very low energies by photosensors suitably designed to
operate at cryogenic temperatures. Liquid Argon based detectors for Dark Matter
searches currently implement photo multiplier tubes for signal read-out. In the
last few years PMTs with photocathodes operating down to liquid Argon
temperatures (87 K) have been specially developed with increasing Quantum
Efficiency characteristics. The most recent of these, Hamamatsu Photonics Mod.
R11065 with peak QE up to about 35%, has been extensively tested within the R&D
program of the WArP Collaboration. During these testes the Hamamatsu PMTs
showed superb performance and allowed obtaining a light yield around 7
phel/keVee in a Liquid Argon detector with a photocathodic coverage in the 12%
range, sufficient for detection of events down to few keVee of energy
deposition. This shows that this new type of PMT is suited for experimental
applications, in particular for new direct Dark Matter searches with LAr-based
experiments
Search for anomalies in the {\nu}e appearance from a {\nu}{\mu} beam
We report an updated result from the ICARUS experiment on the search for
{\nu}{\mu} ->{\nu}e anomalies with the CNGS beam, produced at CERN with an
average energy of 20 GeV and travelling 730 km to the Gran Sasso Laboratory.
The present analysis is based on a total sample of 1995 events of CNGS neutrino
interactions, which corresponds to an almost doubled sample with respect to the
previously published result. Four clear {\nu}e events have been visually
identified over the full sample, compared with an expectation of 6.4 +- 0.9
events from conventional sources. The result is compatible with the absence of
additional anomalous contributions. At 90% and 99% confidence levels the limits
to possible oscillated events are 3.7 and 8.3 respectively. The corresponding
limit to oscillation probability becomes consequently 3.4 x 10-3 and 7.6 x 10-3
respectively. The present result confirms, with an improved sensitivity, the
early result already published by the ICARUS collaboration
Precision measurement of the neutrino velocity with the ICARUS detector in the CNGS beam
During May 2012, the CERN-CNGS neutrino beam has been operated for two weeks
for a total of 1.8 10^17 pot in bunched mode, with a 3 ns narrow width proton
beam bunches, separated by 100 ns. This tightly bunched beam structure allows a
very accurate time of flight measurement of neutrinos from CERN to LNGS on an
event-by-event basis. Both the ICARUS-T600 PMT-DAQ and the CERN-LNGS timing
synchronization have been substantially improved for this campaign, taking
ad-vantage of additional independent GPS receivers, both at CERN and LNGS as
well as of the deployment of the "White Rabbit" protocol both at CERN and LNGS.
The ICARUS-T600 detector has collected 25 beam-associated events; the
corresponding time of flight has been accurately evaluated, using all different
time synchronization paths. The measured neutrino time of flight is compatible
with the arrival of all events with speed equivalent to the one of light: the
difference between the expected value based on the speed of light and the
measured value is tof_c - tof_nu = (0.10 \pm 0.67stat. \pm 2.39syst.) ns. This
result is in agreement with the value previously reported by the ICARUS
collaboration, tof_c - tof_nu = (0.3 \pm 4.9stat. \pm 9.0syst.) ns, but with
improved statistical and systematic errors.Comment: 21 pages, 13 figures, 1 tabl
AGILE detection of delayed gamma-ray emission from GRB 080514B
GRB 080514B is the first gamma ray burst (GRB), since the time of EGRET, for
which individual photons of energy above several tens of MeV have been detected
with a pair-conversion tracker telescope. This burst was discovered with the
Italian AGILE gamma-ray satellite. The GRB was localized with a cooperation by
AGILE and the interplanetary network (IPN). The gamma-ray imager (GRID)
estimate of the position, obtained before the SuperAGILE-IPN localization, is
found to be consistent with the burst position. The hard X-ray emission
observed by SuperAGILE lasted about 7 s, while there is evidence that the
emission above 30 MeV extends for a longer duration (at least ~13 s). Similar
behavior was seen in the past from a few other GRBs observed with EGRET.
However, the latter measurements were affected, during the brightest phases, by
instrumental dead time effects, resulting in only lower limits to the burst
intensity. Thanks to the small dead time of the AGILE/GRID we could assess that
in the case of GRB 080514B the gamma-ray to X-ray flux ratio changes
significantly between the prompt and extended emission phase.Comment: A&A letters, in pres
A Proposal for a Three Detector Short-Baseline Neutrino Oscillation Program in the Fermilab Booster Neutrino Beam
A Short-Baseline Neutrino (SBN) physics program of three LAr-TPC detectors
located along the Booster Neutrino Beam (BNB) at Fermilab is presented. This
new SBN Program will deliver a rich and compelling physics opportunity,
including the ability to resolve a class of experimental anomalies in neutrino
physics and to perform the most sensitive search to date for sterile neutrinos
at the eV mass-scale through both appearance and disappearance oscillation
channels. Using data sets of 6.6e20 protons on target (P.O.T.) in the LAr1-ND
and ICARUS T600 detectors plus 13.2e20 P.O.T. in the MicroBooNE detector, we
estimate that a search for muon neutrino to electron neutrino appearance can be
performed with ~5 sigma sensitivity for the LSND allowed (99% C.L.) parameter
region. In this proposal for the SBN Program, we describe the physics analysis,
the conceptual design of the LAr1-ND detector, the design and refurbishment of
the T600 detector, the necessary infrastructure required to execute the
program, and a possible reconfiguration of the BNB target and horn system to
improve its performance for oscillation searches.Comment: 209 pages, 129 figure
Multiwavelength observations of 3C 454.3. I. The AGILE 2007 November campaign on the "Crazy Diamond"
[Abridged] We report on a multiwavelength observation of the blazar 3C 454.3
(which we dubbed "crazy diamond") carried out on November 2007 by means of the
astrophysical satellites AGILE, INTEGRAL, Swift, the WEBT Consortium, and the
optical-NIR telescope REM. 3C 454.3 is detected at a level
during the 3-week observing period, with an average flux above 100 MeV of
\phcmsec. The gamma-ray
spectrum can be fit with a single power-law with photon index between 100 MeV and 1 GeV. We detect significant
day-by-day variability of the gamma-ray emission during our observations, and
we can exclude that the fluxes are constant at the 99.6% ()
level. The source was detected typically around 40 degrees off-axis, and it was
substantially off--axis in the field of view of the AGILE hard X-ray imager.
However, a 5-day long ToO observation by INTEGRAL detected 3C 454.3 at an
average flux of about \phcmsec with
an average photon index of between 20--200
keV. Swift also detected 3C 454.3 with a flux in the 0.3--10 keV energy band in
the range \phcmsec{} and a photon index in the
range . In the optical band, both WEBT and REM
show an extremely variable behavior in the band. A correlation analysis
based on the entire data set is consistent with no time-lags between the
gamma-ray and the optical flux variations. Our simultaneous multifrequency
observations strongly indicate that the dominant emission mechanism between 30
MeV and 30 GeV is dominated by inverse Compton scattering of relativistic
electrons in the jet on the external photons from the broad line region.Comment: Accepted for publication in ApJ. Abridged Abstract. 37 pages, 14
Figures, 3 Table
AGILE observation of a gamma-ray flare from the blazar 3C 279
Context. We report the detection by the AGILE satellite of an intense
gamma-ray flare from the gamma-ray source 3EG J1255-0549, associated to the
Flat Spectrum Radio Quasar 3C 279, during the AGILE pointings towards the Virgo
Region on 2007 July 9-13.
Aims. The simultaneous optical, X-ray and gamma-ray covering allows us to
study the spectral energy distribution (SED) and the theoretical models
relative to the flaring episode of mid-July.
Methods. AGILE observed the source during its Science Performance
Verification Phase with its two co-aligned imagers: the Gamma- Ray Imaging
Detector (GRID) and the hard X-ray imager (Super-AGILE) sensitive in the 30 MeV
- 50 GeV and 18 - 60 keV respectively. During the AGILE observation the source
was monitored simultaneously in optical band by the REM telescope and in the
X-ray band by the Swift satellite through 4 ToO observations.
Results. During 2007 July 9-13 July 2007, AGILE-GRID detected gamma-ray
emission from 3C 279, with the source at ~2 deg from the center of the Field of
View, with an average flux of (210+-38) 10^-8 ph cm^-2 s^-1 for energy above
100 MeV. No emission was detected by Super-AGILE, with a 3-sigma upper limit of
10 mCrab. During the observation lasted about 4 days no significative gamma-ray
flux variation was observed.
Conclusions. The Spectral Energy Distribution is modelled with a homogeneous
one-zone Synchrotron Self Compton emission plus the contributions by external
Compton scattering of direct disk radiation and, to a lesser extent, by
external Compton scattering of photons from the Broad Line Region.Comment: Accepted for publication in Astronomy and Astrophysic
First AGILE Catalog of High Confidence Gamma-Ray Sources
We present the first catalog of high-confidence gamma-ray sources detected by
the AGILE satellite during observations performed from July 9, 2007 to June 30,
2008. Catalogued sources are detected by merging all the available data over
the entire time period. AGILE, launched in April 2007, is an ASI mission
devoted to gamma-ray observations in the 30 MeV - 50 GeV energy range, with
simultaneous X-ray imaging capability in the 18-60 keV band. This catalog is
based on Gamma-Ray Imaging Detector (GRID) data for energies greater than 100
MeV. For the first AGILE catalog we adopted a conservative analysis, with a
high-quality event filter optimized to select gamma-ray events within the
central zone of the instrument Field of View (radius of 40 degrees). This is a
significance-limited (4 sigma) catalog, and it is not a complete flux-limited
sample due to the non-uniform first year AGILE sky coverage. The catalog
includes 47 sources, 21 of which are associated with confirmed or candidate
pulsars, 13 with Blazars (7 FSRQ, 4 BL Lacs, 2 unknown type), 2 with HMXRBs, 2
with SNRs, 1 with a colliding-wind binary system, 8 with unidentified sources.Comment: Revised version, 15 pages, 3 figures, 3 tables. To be published in
Astronomy and Astrophysics. Text improved and clarified. Refined analysis of
complex regions of the Galactic plane yields a new list of high-confidence
sources including 47 sources (compared with the 40 sources appearing in the
first version
Search for anomalies in the neutrino sector with muon spectrometers and large LArTPC imaging detectors at CERN
A new experiment with an intense ~2 GeV neutrino beam at CERN SPS is proposed
in order to definitely clarify the possible existence of additional neutrino
states, as pointed out by neutrino calibration source experiments, reactor and
accelerator experiments and measure the corresponding oscillation parameters.
The experiment is based on two identical LAr-TPCs complemented by magnetized
spectrometers detecting electron and muon neutrino events at Far and Near
positions, 1600 m and 300 m from the proton target, respectively. The ICARUS
T600 detector, the largest LAr-TPC ever built with a size of about 600 ton of
imaging mass, now running in the LNGS underground laboratory, will be moved at
the CERN Far position. An additional 1/4 of the T600 detector (T150) will be
constructed and located in the Near position. Two large area spectrometers will
be placed downstream of the two LAr-TPC detectors to perform charge
identification and muon momentum measurements from sub-GeV to several GeV
energy range, greatly complementing the physics capabilities. This experiment
will offer remarkable discovery potentialities, collecting a very large number
of unbiased events both in the neutrino and antineutrino channels, largely
adequate to definitely settle the origin of the observed neutrino-related
anomalies.Comment: Contribution to the European Strategy for Particle Physics - Open
Symposium Preparatory Group, Kracow 10-12 September 201
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