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result(s) for
"Gay, Andre N."
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Acute Operative Management of Humeral Shaft Fractures: Analysis of the National Trauma Data Bank
2015
Advances in surgical techniques have increased the role of early surgical intervention for isolated diaphyseal humerus fractures. The goal of this study was to investigate the following: (1) the current trend of operative treatment; (2) factors that affect surgical treatment; and (3) the effect of surgical fixation on length of stay, complication rates, and hospital disposition. The National Trauma Data Bank from 2004 to 2006 was analyzed. All patients with multiple injuries that included closed humeral shaft fractures and all patients with isolated humeral shaft fractures were included. Of 2312 total closed humeral shaft fractures, 1662 had a documented procedure code. A total of 47% of patients underwent surgical treatment. Surgically treated patients were on average 3.5 years older than those treated nonoperatively ( P =.007). A total of 49% of white patients underwent early surgery vs 39% of nonwhite patients ( P <.001). The operative group had a mean Injury Severity Score of 8.33 vs 9.0 in the nonoperative group ( P =.04). Treatment at a Level I trauma center decreased the likelihood of surgery compared with treatment at a non-Level I trauma center (45% vs 57%, P <.001). Mean length of stay was 4.6 days for operative treatment vs 3.9 days for nonoperative treatment ( P =.02). Of patients who underwent surgery, 78% were discharged to home compared with 69% of those managed nonoperatively ( P <.001). Acute operative management of humeral shaft fractures correlated with a lower Injury Severity Score, a decreased length of stay, and less rehabilitation placement. Furthermore, older patients, white patients, and patients treated at a non-Level I trauma center were more likely to undergo acute surgical management. The reasons for these disparities are unclear and warrant further investigation. [ Orthopedics. 2015; 38(6):e485–e489.]
Journal Article
Measuring the atmospheric neutrino oscillation parameters and constraining the 3+1 neutrino model with ten years of ANTARES data
by
Bertin, V.
,
Le Breton, R.
,
Chabab, M.
in
Astrofísica
,
Astronomia i astrofísica
,
Classical and Quantum Gravitation
2019
A
bstract
The ANTARES neutrino telescope has an energy threshold of a few tens of GeV. This allows to study the phenomenon of atmospheric muon neutrino disappearance due to neutrino oscillations. In a similar way, constraints on the 3+1 neutrino model, which foresees the existence of one sterile neutrino, can be inferred. Using data collected by the ANTARES neutrino telescope from 2007 to 2016, a new measurement of Δ
m
32
2
and
θ
23
has been performed — which is consistent with world best-fit values — and constraints on the 3+1 neutrino model have been derived.
Journal Article
The cosmic ray shadow of the Moon observed with the ANTARES neutrino telescope
2018
One of the main objectives of the ANTARES telescope is the search for point-like neutrino sources. Both the pointing accuracy and the angular resolution of the detector are important in this context and a reliable way to evaluate this performance is needed. In order to measure the pointing accuracy of the detector, one possibility is to study the shadow of the Moon, i.e. the deficit of the atmospheric muon flux from the direction of the Moon induced by the absorption of cosmic rays. Analysing the data taken between 2007 and 2016, the Moon shadow is observed with \\[3.5\\sigma \\] statistical significance. The detector angular resolution for downward-going muons is \\[0.73^{\\circ }\\pm 0.14^{\\circ }.\\] The resulting pointing performance is consistent with the expectations. An independent check of the telescope pointing accuracy is realised with the data collected by a shower array detector onboard of a ship temporarily moving around the ANTARES location.
Journal Article
All-sky search for high-energy neutrinos from gravitational wave event GW170104 with the Antares neutrino telescope
by
Bertin, V.
,
Hernández-Rey, J. J.
,
Lotze, M.
in
Astrofísica
,
Astronomia i astrofísica
,
Astronomy
2017
Advanced
LIGO
detected a significant gravitational wave signal (GW170104) originating from the coalescence of two black holes during the second observation run on January 4th, 2017. An all-sky high-energy neutrino follow-up search has been made using data from the
Antares
neutrino telescope, including both upgoing and downgoing events in two separate analyses. No neutrino candidates were found within
±
500
s around the GW event time nor any time clustering of events over an extended time window of
±
3
months. The non-detection is used to constrain isotropic-equivalent high-energy neutrino emission from GW170104 to less than
∼
1.2
×
10
55
erg for a
E
-
2
spectrum. This constraint is valid in the energy range corresponding to the 5–95% quantiles of the neutrino flux [3.2 TeV; 3.6 PeV], if the GW emitter was below the
Antares
horizon at the alert time.
Journal Article
Acoustic positioning for deep sea neutrino telescopes with a system of piezo sensors integrated into glass spheres
by
El Hedri, S.
,
Bertin, V.
,
Chabab, M.
in
Astrophysics
,
Instrumentation and Methods for Astrophysic
,
Physics
2025
Abstract Position calibration in the deep sea is typically done by means of acoustic multilateration using three or more acoustic emitters installed at known positions. Rather than using hydrophones as receivers that are exposed to the ambient pressure, the sound signals can be coupled to piezo ceramics glued to the inside of existing containers for electronics or measuring instruments of a deep sea infrastructure. The ANTARES neutrino telescope operated from 2006 until 2022 in the Mediterranean Sea at a depth exceeding 2000 m . It comprised nearly 900 glass spheres with 432 mm diameter and 15 mm thickness, equipped with photomultiplier tubes to detect Cherenkov light from tracks of charged elementary particles. In an experimental setup within ANTARES, piezo sensors have been glued to the inside of such – otherwise empty – glass spheres. These sensors recorded signals from acoustic emitters with frequencies from 46545 to 60235 Hz . Two waves propagating through the glass sphere are found as a result of the excitation by the waves in the water. These can be qualitatively associated with symmetric and asymmetric Lamb-like waves of zeroth order: a fast (early) one with $$\\varvec{v_e \\approx 5\\,{\\textbf {mm}}/\\mu \\text {s}}$$ v e ≈ 5 mm / μ s and a slow (late) one with $$\\varvec{v_\\ell \\approx \\,2\\,{\\textbf {mm}}/\\mu \\text {s}}$$ v ℓ ≈ 2 mm / μ s . Taking these findings into account improves the accuracy of the position calibration. The results can be transferred to the KM3NeT neutrino telescope, currently under construction at multiple sites in the Mediterranean Sea, for which the concept of piezo sensors glued to the inside of glass spheres has been adapted for monitoring the positions of the photomultiplier tubes.
Journal Article
Long-term monitoring of the ANTARES optical module efficiencies using \\^{40}\\mathrm{{K}}\\ decays in sea water
2018
Cherenkov light induced by radioactive decay products is one of the major sources of background light for deep-sea neutrino telescopes such as ANTARES. These decays are at the same time a powerful calibration source. Using data collected by the ANTARES neutrino telescope from mid 2008 to 2017, the time evolution of the photon detection efficiency of optical modules is studied. A modest loss of only 20% in 9 years is observed. The relative time calibration between adjacent modules is derived as well.
Journal Article
All-sky search for high-energy neutrinos from gravitational wave event GW170104 with the Antares neutrino telescope
2017
Advanced LIGO detected a significant gravitational wave signal (GW170104) originating from the coalescence of two black holes during the second observation run on January 4th, 2017. An all-sky high-energy neutrino follow-up search has been made using data from the Antares neutrino telescope, including both upgoing and downgoing events in two separate analyses. No neutrino candidates were found within [Formula omitted] s around the GW event time nor any time clustering of events over an extended time window of [Formula omitted] months. The non-detection is used to constrain isotropic-equivalent high-energy neutrino emission from GW170104 to less than [Formula omitted] erg for a [Formula omitted] spectrum. This constraint is valid in the energy range corresponding to the 5-95% quantiles of the neutrino flux [3.2 TeV; 3.6 PeV], if the GW emitter was below the Antares horizon at the alert time.
Journal Article
Constraints on the energy spectrum of the diffuse cosmic neutrino flux from the ANTARES neutrino telescope
2024
High-significance evidences of the existence of a high-energy diffuse flux of cosmic neutrinos have emerged in the last decade from several observations by the IceCube Collaboration. The ANTARES neutrino telescope took data for 15 years in the Mediterranean Sea, from 2007 to 2022, and collected a high-purity all-flavour neutrino sample. The search for a diffuse cosmic neutrino signal using this dataset is presented in this article. This final analysis did not provide a statistically significant observation of the cosmic diffuse flux. However, this is converted into limits on the properties of the cosmic neutrino spectrum. In particular, given the sensitivity of the ANTARES neutrino telescope between 1 and 50 TeV, constraints on single-power-law hypotheses are derived for the cosmic diffuse flux below 20 TeV, especially for power-law fits of the IceCube data with spectral index softer than 2.8.
Hint for a TeV neutrino emission from the Galactic Ridge with ANTARES
2023
Interactions of cosmic ray protons, atomic nuclei, and electrons in the interstellar medium in the inner part of the Milky Way produce a \\(\\gamma\\)-ray flux from the Galactic Ridge. If the \\(\\gamma\\)-ray emission is dominated by proton and nuclei interactions, a neutrino flux comparable to the \\(\\gamma\\)-ray flux is expected from the same sky region. Data collected by the ANTARES neutrino telescope are used to constrain the neutrino flux from the Galactic Ridge in the 1-100 TeV energy range. Neutrino events reconstructed both as tracks and showers are considered in the analysis and the selection is optimized for the search of an excess in the region \\(|l| < 30\\deg\\), \\(|b| < 2\\deg\\). The expected background in the search region is estimated using an off-zone region with similar sky coverage. Neutrino signal originating from a power-law spectrum with spectral index ranging from \\(\\Gamma_\\nu=1\\) to \\(4\\) is simulated in both channels. The observed energy distributions are fitted to constrain the neutrino emission from the Ridge. The energy distributions in the signal region are inconsistent with the background expectation at \\(\\sim 96\\%\\) confidence level. The mild excess over the background is consistent with a neutrino flux with a power law with a spectral index \\(2.45^{+0.22}_{-0.34}\\) and a flux normalization \\(dN_\\nu/dE_\\nu = 4.0^{+2.7}_{-2.0} \\times 10^{-16} \\text{GeV}^{-1} \\text{cm}^{-2} \\text{s}^{-1} \\text{sr}^{-1}\\) at 40 TeV reference energy. Such flux is consistent with the expected neutrino signal if the bulk of the observed \\(\\gamma\\)-ray flux from the Galactic Ridge originates from interactions of cosmic ray protons and nuclei with a power-law spectrum extending well into the PeV energy range.
Search for neutrino counterparts to the gravitational wave sources from LIGO/Virgo O3 run with the ANTARES detector
2023
Since 2015 the LIGO and Virgo interferometers have detected gravitational waves from almost one hundred coalescences of compact objects (black holes and neutron stars). This article presents the results of a search performed with data from the ANTARES telescope to identify neutrino counterparts to the gravitational wave sources detected during the third LIGO/Virgo observing run and reported in the catalogues GWTC-2, GWTC-2.1, and GWTC-3. This search is sensitive to all-sky neutrinos of all flavours and of energies \\(>100\\) GeV, thanks to the inclusion of both track-like events (mainly induced by \\(\\nu_\\mu\\) charged-current interactions) and shower-like events (induced by other interaction types). Neutrinos are selected if they are detected within \\(\\pm 500\\) s from the GW merger and with a reconstructed direction compatible with its sky localisation. No significant excess is found for any of the 80 analysed GW events, and upper limits on the neutrino emission are derived. Using the information from the GW catalogues and assuming isotropic emission, upper limits on the total energy \\(E_{\\rm tot, \\nu}\\) emitted as neutrinos of all flavours and on the ratio \\(f_\\nu = E_{\\rm tot, \\nu}/E_{\\rm GW}\\) between neutrino and GW emissions are also computed. Finally, a stacked analysis of all the 72 binary black hole mergers (respectively the 7 neutron star - black hole merger candidates) has been performed to constrain the typical neutrino emission within this population, leading to the limits: \\(E_{\\rm tot, \\nu} < 4.0 \\times 10^{53}\\) erg and \\(f_\\nu < 0.15\\) (respectively, \\(E_{\\rm tot, \\nu} < 3.2 \\times 10^{53}\\) erg and \\(f_\\nu < 0.88\\)) for \\(E^{-2}\\) spectrum and isotropic emission. Other assumptions including softer spectra and non-isotropic scenarios have also been tested.