6,458 research outputs found

    Hint for a TeV neutrino emission from the Galactic Ridge with ANTARES

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    International audienceInteractions of cosmic ray protons, atomic nuclei, and electrons in the interstellar medium in the inner part of the Milky Way produce a γ\gamma-ray flux from the Galactic Ridge. If the γ\gamma-ray emission is dominated by proton and nuclei interactions, a neutrino flux comparable to the γ\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∣<30deg⁡|l| < 30\deg, ∣b∣<2deg⁡|b| < 2\deg. The expected background in the search region is estimated using an off region with similar sky coverage. Neutrino signal originating from a power-law spectrum with slope ranging from Γν=1\Gamma_\nu=1 to 44 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 ∼96%\sim 96\% confidence level. The mild excess over the background is consistent with a neutrino flux with a power law with a slope 2.45−0.34+0.222.45^{+0.22}_{-0.34} and a flux normalization dNν/dEν=4.0−2.0+2.7×10−16GeV−1cm−2s−1sr−1dN_\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 γ\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

    The high-albedo, low polarization disk around HD 114082 harbouring a Jupiter-sized transiting planet

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    We present new optical and near-IR images of debris disk around the F-type star HD 114082. We obtained direct imaging observations and analysed the TESS photometric time series data of this target with a goal to search for planetary companions and to characterise the morphology of the debris disk and the scattering properties of dust particles. HD 114082 was observed with the VLT/SPHERE instrument: the IRDIS camera in the K band together with the IFS in the Y, J and H band using the ADI technique as well as IRDIS in the H band and ZIMPOL in the I_PRIME band using the PDI technique. The scattered light images were fitted with a 3D model for single scattering in an optically thin dust disk. We performed aperture photometry in order to derive the scattering and polarized phase functions, polarization fraction and spectral scattering albedo for the dust particles in the disk. This method was also used to obtain the reflectance spectrum of the disk to retrieve the disk color and study the dust reflectivity in comparison to the debris disk HD 117214. We also performed the modeling of the HD 114082 light curve measured by TESS using the models for planet transit and stellar activity to put constraints on radius of the detected planet and its orbit. The debris disk appears as an axisymmetric debris belt with a radius of ~0.37"" (35 au), inclination of ~83∘^\circ and a wide inner cavity. Dust particles in HD 114082 have a maximum polarization fraction of ~17% and a high reflectivity which results in a spectral scattering albedo of 0.65. The analysis of TESS photometric data reveals a transiting planetary companion to HD 114082 with a radius of ∼\sim1~RJ\rm R_{J} on an orbit with a semi-major axis of 0.7±0.40.7 \pm 0.4 au. Combining different data, we reach deep sensitivity limits in terms of companion masses down to ~5MJupM_{\rm Jup} at 50 au, and ~10 MJupM_{\rm Jup} at 30 au from the central star.Comment: 27 page

    Modifications of lung microbiota structure in traumatic brain injury ventilated patients according to time and enteral feeding formulas: a prospective randomized study

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    Abstract Background Specialized diets enriched with immune nutrients could be an important supplement in patients (pts) with acute traumatic brain injury (TBI). Omega-3 and arginine may interact with immune response and microbiota. No data are available about the role of the specialized diets in modulating the lung microbiota, and little is known about the influence of lung microbiota structure in development of ventilator-associated pneumonia (VAP) in TBI pts. The aims of this study are to evaluate the impact of specific nutrients on the lung microbiota and the variation of lung microbiota in TBI pts developing VAP. Methods A cohort of 31 TBI pts requiring mechanical ventilation in ICU was randomized for treatment with specialized (16pts) or standard nutrition (15pts). Alpha and beta diversity of lung microbiota were analyzed from bronco Alveolar Lavage (BAL) samples collected at admission and 7 days post-ICU admission in both groups. A further analysis was carried out on the same samples retrospectively grouped in VAP or no VAP pts. Results None developed VAP in the first week. Thereafter, ten out of thirty-one pts developed VAP. The BAL microbiota on VAP group showed significant differences in beta diversity and Staphylococcus and Acinetobacter Genera were high. The specialized nutrition had influence on beta diversity that reached statistical significance only in Bray–Curtis distance. Conclusion Our data suggest that TBI patients who developed VAP during ICU stay have different structures of BAL microbiota either at admission and at 7 days post-ICU admission, while no correlation has been observed between different enteral formulas and microbiota composition in terms of richness and evenness. These findings suggest that targeting the lung microbiota may be a promising approach for preventing infections in critically ill patients

    SARS-CoV-2 omicron (B.1.1.529)-related COVID-19 sequelae in vaccinated and unvaccinated patients with cancer: results from the OnCovid registry

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    Background: COVID-19 sequelae can affect about 15% of patients with cancer who survive the acute phase of SARS-CoV-2 infection and can substantially impair their survival and continuity of oncological care. We aimed to investigate whether previous immunisation affects long-term sequelae in the context of evolving variants of concern of SARS-CoV-2. Methods: OnCovid is an active registry that includes patients aged 18 years or older from 37 institutions across Belgium, France, Germany, Italy, Spain, and the UK with a laboratory-confirmed diagnosis of COVID-19 and a history of solid or haematological malignancy, either active or in remission, followed up from COVID-19 diagnosis until death. We evaluated the prevalence of COVID-19 sequelae in patients who survived COVID-19 and underwent a formal clinical reassessment, categorising infection according to the date of diagnosis as the omicron (B.1.1.529) phase from Dec 15, 2021, to Jan 31, 2022; the alpha (B.1.1.7)–delta (B.1.617.2) phase from Dec 1, 2020, to Dec 14, 2021; and the pre-vaccination phase from Feb 27 to Nov 30, 2020. The prevalence of overall COVID-19 sequelae was compared according to SARS-CoV-2 immunisation status and in relation to post-COVID-19 survival and resumption of systemic anticancer therapy. This study is registered with ClinicalTrials.gov, NCT04393974. Findings: At the follow-up update on June 20, 2022, 1909 eligible patients, evaluated after a median of 39 days (IQR 24–68) from COVID-19 diagnosis, were included (964 [50·7%] of 1902 patients with sex data were female and 938 [49·3%] were male). Overall, 317 (16·6%; 95% CI 14·8–18·5) of 1909 patients had at least one sequela from COVID-19 at the first oncological reassessment. The prevalence of COVID-19 sequelae was highest in the pre-vaccination phase (191 [19·1%; 95% CI 16·4–22·0] of 1000 patients). The prevalence was similar in the alpha–delta phase (110 [16·8%; 13·8–20·3] of 653 patients, p=0·24), but significantly lower in the omicron phase (16 [6·2%; 3·5–10·2] of 256 patients, p&lt;0·0001). In the alpha–delta phase, 84 (18·3%; 95% CI 14·6–22·7) of 458 unvaccinated patients and three (9·4%; 1·9–27·3) of 32 unvaccinated patients in the omicron phase had sequelae. Patients who received a booster and those who received two vaccine doses had a significantly lower prevalence of overall COVID-19 sequelae than unvaccinated or partially vaccinated patients (ten [7·4%; 95% CI 3·5–13·5] of 136 boosted patients, 18 [9·8%; 5·8–15·5] of 183 patients who had two vaccine doses vs 277 [18·5%; 16·5–20·9] of 1489 unvaccinated patients, p=0·0001), respiratory sequelae (six [4·4%; 1·6–9·6], 11 [6·0%; 3·0–10·7] vs 148 [9·9%; 8·4–11·6], p=0·030), and prolonged fatigue (three [2·2%; 0·1–6·4], ten [5·4%; 2·6–10·0] vs 115 [7·7%; 6·3–9·3], p=0·037). Interpretation: Unvaccinated patients with cancer remain highly vulnerable to COVID-19 sequelae irrespective of viral strain. This study confirms the role of previous SARS-CoV-2 immunisation as an effective measure to protect patients from COVID-19 sequelae, disruption of therapy, and ensuing mortality. Funding: UK National Institute for Health and Care Research Imperial Biomedical Research Centre and the Cancer Treatment and Research Trust

    PIP4K2B is mechanoresponsive and controls heterochromatin-driven nuclear softening through UHRF1

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    Phosphatidylinositol-5-phosphate (PtdIns5P)-4-kinases (PIP4Ks) are stress-regulated phosphoinositide kinases able to phosphorylate PtdIns5P to PtdIns(4,5)P2. In cancer patients their expression is typically associated with bad prognosis. Among the three PIP4K isoforms expressed in mammalian cells, PIP4K2B is the one with more prominent nuclear localisation. Here, we unveil the role of PIP4K2B as a mechanoresponsive enzyme. PIP4K2B protein level strongly decreases in cells growing on soft substrates. Its direct silencing or pharmacological inhibition, mimicking cell response to softness, triggers a concomitant reduction of the epigenetic regulator UHRF1 and induces changes in nuclear polarity, nuclear envelope tension and chromatin compaction. This substantial rewiring of the nucleus mechanical state drives YAP cytoplasmic retention and impairment of its activity as transcriptional regulator, finally leading to defects in cell spreading and motility. Since YAP signalling is essential for initiation and growth of human malignancies, our data suggest that potential therapeutic approaches targeting PIP4K2B could be beneficial in the control of the altered mechanical properties of cancer cells

    Fermi-GBM Discovery of GRB 221009A: An Extraordinarily Bright GRB from Onset to Afterglow

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    We report the discovery of GRB 221009A, the highest flux gamma-ray burst ever observed by the Fermi Gamma-ray Burst Monitor (GBM). This GRB has continuous prompt emission lasting more than 600 seconds which smoothly transitions to afterglow visible in the GBM energy range (8 keV--40 MeV), and total energetics higher than any other burst in the GBM sample. By using a variety of new and existing analysis techniques we probe the spectral and temporal evolution of GRB 221009A. We find no emission prior to the GBM trigger time (t0; 2022 October 9 at 13:16:59.99 UTC), indicating that this is the time of prompt emission onset. The triggering pulse exhibits distinct spectral and temporal properties suggestive of the thermal, photospheric emission of shock-breakout, with significant emission up to ∼\sim15 MeV. We characterize the onset of external shock at t0+600 s and find evidence of a plateau region in the early-afterglow phase which transitions to a slope consistent with Swift-XRT afterglow measurements. We place the total energetics of GRB 221009A in context with the rest of the GBM sample and find that this GRB has the highest total isotropic-equivalent energy (Eγ,iso=1.0×1055\textrm{E}_{\gamma,\textrm{iso}}=1.0\times10^{55} erg) and second highest isotropic-equivalent luminosity (Lγ,iso=9.9×1053\textrm{L}_{\gamma,\textrm{iso}}=9.9\times10^{53} erg/s) based on redshift of z = 0.151. These extreme energetics are what allowed us to observe the continuously emitting central engine of GBM from the beginning of the prompt emission phase through the onset of early afterglow.Comment: 26 pages 7 figures - accepted for publication in ApJ

    KM3NeT broadcast optical data transport system

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    International audienceThe optical data transport system of the KM3NeT neutrino telescope at the bottom of the Mediterranean Sea will provide more than 6000 optical modules in the detector arrays with a point-to-point optical connection to the control stations onshore. The ARCA and ORCA detectors of KM3NeT are being installed at a depth of about 3500 m and 2500 m, respectively and their distance to the control stations is about 100 kilometers and 40 kilometers. In particular, the two detectors are optimised for the detection of cosmic neutrinos with energies above about 1 TeV (ARCA) and for the detection of atmospheric neutrinos with energies in the range 1 GeV–1 TeV (ORCA). The expected maximum data rate is 200 Mbps per optical module. The implemented optical data transport system matches the layouts of the networks of electro-optical cables and junction boxes in the deep sea. For efficient use of the fibres in the system the technology of Dense Wavelength Division Multiplexing is applied. The performance of the optical system in terms of measured bit error rates, optical budget are presented. The next steps in the implementation of the system are also discussed

    Probing invisible neutrino decay with KM3NeT-ORCA

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    International audienceIn the era of precision measurements of the neutrino oscillation parameters, upcoming neutrino experiments will also be sensitive to physics beyond the Standard Model. KM3NeT/ORCA is a neutrino detector optimised for measuring atmospheric neutrinos from a few GeV to around 100 GeV. In this paper, the sensitivity of the KM3NeT/ORCA detector to neutrino decay has been explored. A three-flavour neutrino oscillation scenario, where the third neutrino mass state ν3\nu_3 decays into an invisible state, e.g. a sterile neutrino, is considered. We find that KM3NeT/ORCA would be sensitive to invisible neutrino decays with 1/α3=τ3/m3<1801/\alpha_3=\tau_3/m_3 < 180~ps/eV\mathrm{ps/eV} at 90%90\% confidence level, assuming true normal ordering. Finally, the impact of neutrino decay on the precision of KM3NeT/ORCA measurements for θ23\theta_{23}, Δm312\Delta m^2_{31} and mass ordering have been studied. No significant effect of neutrino decay on the sensitivity to these measurements has been found

    Searches for neutrinos in the direction of radio-bright blazars with the ANTARES telescope

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    International audienceActive galaxies, especially blazars, are among the most promising neutrino source candidates. To date, ANTARES searches for these objects considered GeV-TeV γ\gamma-ray bright blazars. Here, a statistically complete radio-bright blazar sample is used as the target for searches of origins of neutrinos collected by the ANTARES neutrino telescope over 13 years of operation. The hypothesis of a neutrino-blazar directional correlation is tested by pair counting and by a complementary likelihood-based approach. The resulting post-trial pp-value is 3.0%3.0\% (2.2σ2.2\sigma in the two-sided convention), possibly indicating a correlation. Additionally, a time-dependent analysis is performed to search for temporal clustering of neutrino candidates as a mean of detecting neutrino flares in blazars. None of the investigated sources alone reaches a significant flare detection level. However, the presence of 18 sources with a pre-trial significance above 3σ3\sigma indicates a p=1.4%p=1.4\% (2.5σ2.5\sigma in the two-sided convention) detection of a time-variable neutrino flux. An \textit{a posteriori} investigation reveals an intriguing temporal coincidence of neutrino, radio, and γ\gamma-ray flares of the J0242+1101 blazar at a p=0.5%p=0.5\% (2.9σ2.9\sigma in the two-sided convention) level. Altogether, the results presented here suggest a possible connection of neutrino candidates detected by the ANTARES telescope with radio-bright blazars
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