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1.
Phys Rev Lett ; 132(15): 151001, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38682982

RESUMEN

We report on a measurement of astrophysical tau neutrinos with 9.7 yr of IceCube data. Using convolutional neural networks trained on images derived from simulated events, seven candidate ν_{τ} events were found with visible energies ranging from roughly 20 TeV to 1 PeV and a median expected parent ν_{τ} energy of about 200 TeV. Considering backgrounds from astrophysical and atmospheric neutrinos, and muons from π^{±}/K^{±} decays in atmospheric air showers, we obtain a total estimated background of about 0.5 events, dominated by non-ν_{τ} astrophysical neutrinos. Thus, we rule out the absence of astrophysical ν_{τ} at the 5σ level. The measured astrophysical ν_{τ} flux is consistent with expectations based on previously published IceCube astrophysical neutrino flux measurements and neutrino oscillations.

3.
Science ; 380(6652): 1338-1343, 2023 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-37384687

RESUMEN

The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth's atmosphere, is unknown. Because of deflection by interstellar magnetic fields, cosmic rays produced within the Milky Way arrive at Earth from random directions. However, cosmic rays interact with matter near their sources and during propagation, which produces high-energy neutrinos. We searched for neutrino emission using machine learning techniques applied to 10 years of data from the IceCube Neutrino Observatory. By comparing diffuse emission models to a background-only hypothesis, we identified neutrino emission from the Galactic plane at the 4.5σ level of significance. The signal is consistent with diffuse emission of neutrinos from the Milky Way but could also arise from a population of unresolved point sources.

6.
Science ; 378(6619): 538-543, 2022 11 04.
Artículo en Inglés | MEDLINE | ID: mdl-36378962

RESUMEN

A supermassive black hole, obscured by cosmic dust, powers the nearby active galaxy NGC 1068. Neutrinos, which rarely interact with matter, could provide information on the galaxy's active core. We searched for neutrino emission from astrophysical objects using data recorded with the IceCube neutrino detector between 2011 and 2020. The positions of 110 known gamma-ray sources were individually searched for neutrino detections above atmospheric and cosmic backgrounds. We found that NGC 1068 has an excess of [Formula: see text] neutrinos at tera-electron volt energies, with a global significance of 4.2σ, which we interpret as associated with the active galaxy. The flux of high-energy neutrinos that we measured from NGC 1068 is more than an order of magnitude higher than the upper limit on emissions of tera-electron volt gamma rays from this source.

7.
Phys Rev Lett ; 129(15): 151801, 2022 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-36269964

RESUMEN

We present a search for an unstable sterile neutrino by looking for a resonant signal in eight years of atmospheric ν_{µ} data collected from 2011 to 2019 at the IceCube Neutrino Observatory. Both the (stable) three-neutrino and the 3+1 sterile neutrino models are disfavored relative to the unstable sterile neutrino model, though with p values of 2.8% and 0.81%, respectively, we do not observe evidence for 3+1 neutrinos with neutrino decay. The best-fit parameters for the sterile neutrino with decay model from this study are Δm_{41}^{2}=6.7_{-2.5}^{+3.9} eV^{2}, sin^{2}2θ_{24}=0.33_{-0.17}^{+0.20}, and g^{2}=2.5π±1.5π, where g is the decay-mediating coupling. The preferred regions of the 3+1+decay model from short-baseline oscillation searches are excluded at 90% C.L.

8.
Phys Rev Lett ; 129(1): 011804, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35841552

RESUMEN

We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter ε_{µτ}. The best-fit value is consistent with no NSI at a p value of 25.2%. With a 90% confidence interval of -0.0041≤ε_{µτ}≤0.0031 along the real axis and similar strength in the complex plane, this result is the strongest constraint on any NSI parameter from any oscillation channel to date.

9.
Phys Rev Lett ; 128(5): 051101, 2022 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-35179913

RESUMEN

We present an all-sky 90% confidence level upper limit on the cosmic flux of relativistic magnetic monopoles using 2886 days of IceCube data. The analysis was optimized for monopole speeds between 0.750c and 0.995c, without any explicit restriction on the monopole mass. We constrain the flux of relativistic cosmic magnetic monopoles to a level below 2.0×10^{-19} cm^{-2} s^{-1} sr^{-1} over the majority of the targeted speed range. This result constitutes the most strict upper limit to date for magnetic monopoles with ß≳0.8 and up to ß∼0.995 and fills the gap between existing limits on the cosmic flux of nonrelativistic and ultrarelativistic magnetic monopoles.

12.
Phys Rev Lett ; 125(14): 141801, 2020 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-33064514

RESUMEN

The results of a 3+1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented. A total of 305 735 muon neutrino events are analyzed in reconstructed energy-zenith space to test for signatures of a matter-enhanced oscillation that would occur given a sterile neutrino state with a mass-squared differences between 0.01 and 100 eV^{2}. The best-fit point is found to be at sin^{2}(2θ_{24})=0.10 and Δm_{41}^{2}=4.5 eV^{2}, which is consistent with the no sterile neutrino hypothesis with a p value of 8.0%.

13.
Phys Rev Lett ; 125(12): 121104, 2020 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-33016752

RESUMEN

We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010-2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated (∼90%) by electron and tau flavors. The flux, observed in the sensitive energy range from 16 TeV to 2.6 PeV, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be γ=2.53±0.07 and a flux normalization for each neutrino flavor of ϕ_{astro}=1.66_{-0.27}^{+0.25} at E_{0}=100 TeV, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices γ≤2.28 at ≥3σ significance level. Because of high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below ∼100 TeV compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p value ≥0.06). The sizable and smooth flux measured below ∼100 TeV remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi Large Area Telescope, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma rays.

14.
Sci Rep ; 10(1): 9139, 2020 06 04.
Artículo en Inglés | MEDLINE | ID: mdl-32499563

RESUMEN

Duchenne Muscular Dystrophy (DMD) is a lethal muscle disorder, caused by mutations in the DMD gene and affects approximately 1:5000-6000 male births. In this report, we identified dysregulation of members of the Dlk1-Dio3 miRNA cluster in muscle biopsies of the GRMD dog model. Of these, we selected miR-379 for a detailed investigation because its expression is high in the muscle, and is known to be responsive to glucocorticoid, a class of anti-inflammatory drugs commonly used in DMD patients. Bioinformatics analysis predicts that miR-379 targets EIF4G2, a translational factor, which is involved in the control of mitochondrial metabolic maturation. We confirmed in myoblasts that EIF4G2 is a direct target of miR-379, and identified the DAPIT mitochondrial protein as a translational target of EIF4G2. Knocking down DAPIT in skeletal myotubes resulted in reduced ATP synthesis and myogenic differentiation. We also demonstrated that this pathway is GC-responsive since treating mice with dexamethasone resulted in reduced muscle expression of miR-379 and increased expression of EIF4G2 and DAPIT. Furthermore, miR-379 seric level, which is also elevated in the plasma of DMD patients in comparison with age-matched controls, is reduced by GC treatment. Thus, this newly identified pathway may link GC treatment to a mitochondrial response in DMD.


Asunto(s)
Glucocorticoides/uso terapéutico , MicroARNs/metabolismo , Mitocondrias/metabolismo , Distrofia Muscular de Duchenne/tratamiento farmacológico , Adenosina Trifosfato/metabolismo , Animales , Sitios de Unión , Dexametasona/farmacología , Modelos Animales de Enfermedad , Perros , Factor 4G Eucariótico de Iniciación/química , Factor 4G Eucariótico de Iniciación/genética , Factor 4G Eucariótico de Iniciación/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Ratones , MicroARNs/química , ATPasas de Translocación de Protón Mitocondriales/antagonistas & inhibidores , ATPasas de Translocación de Protón Mitocondriales/genética , ATPasas de Translocación de Protón Mitocondriales/metabolismo , Músculo Esquelético/metabolismo , Distrofia Muscular de Duchenne/genética , Mioblastos Esqueléticos/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/metabolismo
15.
Phys Rev Lett ; 124(5): 051103, 2020 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-32083934

RESUMEN

This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above ∼1 TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. The most significant point in the northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of 2.9σ after accounting for statistical trials from the entire catalog. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506+056, suggests that, collectively, correlations with sources in the northern catalog are inconsistent with background at 3.3σ significance. The southern catalog is consistent with background. These results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.

17.
Phys Rev Lett ; 122(5): 051102, 2019 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-30822017

RESUMEN

High-energy neutrino emission has been predicted for several short-lived astrophysical transients including gamma-ray bursts (GRBs), core-collapse supernovae with choked jets, and neutron star mergers. IceCube's optical and x-ray follow-up program searches for such transient sources by looking for two or more muon neutrino candidates in directional coincidence and arriving within 100 s. The measured rate of neutrino alerts is consistent with the expected rate of chance coincidences of atmospheric background events and no likely electromagnetic counterparts have been identified in Swift follow-up observations. Here, we calculate generic bounds on the neutrino flux of short-lived transient sources. Assuming an E^{-2.5} neutrino spectrum, we find that the neutrino flux of rare sources, like long gamma-ray bursts, is constrained to <5% of the detected astrophysical flux and the energy released in neutrinos (100 GeV to 10 PeV) by a median bright GRB-like source is <10^{52.5} erg. For a harder E^{-2.13} neutrino spectrum up to 30% of the flux could be produced by GRBs and the allowed median source energy is <10^{52} erg. A hypothetical population of transient sources has to be more common than 10^{-5} Mpc^{-3} yr^{-1} (5×10^{-8} Mpc^{-3} yr^{-1} for the E^{-2.13} spectrum) to account for the complete astrophysical neutrino flux.

18.
Intensive Crit Care Nurs ; 48: 21-27, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30033213

RESUMEN

OBJECTIVES: To investigate the relationship between communication and job satisfaction and their association with intention to leave and burnout among intensive care unit nurses. RESEARCH METHODOLOGY/DESIGN: A multicentre questionnaire study. SETTING/PARTICIPANTS: Intensive care nurses (n = 303) from three Flemish hospitals. MAIN OUTCOME MEASURES: Communication satisfaction assessed by the Communication Satisfaction Questionnaire, intention to leave through the Turnover Intention Scale (from the Questionnaire for the Perception and Assessment of Labour) and burnout by the Maslach Burnout Inventory. Job satisfaction was measured by a visual analogue scale. RESULTS: Average job satisfaction was 7.66 ±â€¯1.34/10. Nurses were most satisfied about 'Communication with supervisor' (68.46%), and most dissatisfied about 'Organisational perspectives' (34.12%). Turnover intention was low among 49.5% (150/290) and high among 6.6% (20/290). Three percent (9/299) of intensive care nurses were at risk for burnout. All dimensions of communication satisfaction were moderately associated with job satisfaction, intention to leave and burnout. CONCLUSION: This study demonstrated high levels of communication and job satisfaction in a sample of nurses in Flanders. Intention to leave and burnout prevalence were low. To a certain extent, communication satisfaction might be associated with job satisfaction, intention to leave and burnout.


Asunto(s)
Agotamiento Profesional , Comunicación , Enfermería de Cuidados Críticos , Satisfacción en el Trabajo , Personal de Enfermería en Hospital/psicología , Adulto , Bélgica , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reorganización del Personal , Encuestas y Cuestionarios
19.
Phys Rev Lett ; 120(7): 071801, 2018 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-29542976

RESUMEN

We present a measurement of the atmospheric neutrino oscillation parameters using three years of data from the IceCube Neutrino Observatory. The DeepCore infill array in the center of IceCube enables the detection and reconstruction of neutrinos produced by the interaction of cosmic rays in Earth's atmosphere at energies as low as ∼5 GeV. That energy threshold permits measurements of muon neutrino disappearance, over a range of baselines up to the diameter of the Earth, probing the same range of L/E_{ν} as long-baseline experiments but with substantially higher-energy neutrinos. This analysis uses neutrinos from the full sky with reconstructed energies from 5.6 to 56 GeV. We measure Δm_{32}^{2}=2.31_{-0.13}^{+0.11}×10^{-3} eV^{2} and sin^{2}θ_{23}=0.51_{-0.09}^{+0.07}, assuming normal neutrino mass ordering. These results are consistent with, and of similar precision to, those from accelerator- and reactor-based experiments.

20.
Clin Microbiol Infect ; 24 Suppl 1: e1-e38, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29544767

RESUMEN

The European Society for Clinical Microbiology and Infectious Diseases, the European Confederation of Medical Mycology and the European Respiratory Society Joint Clinical Guidelines focus on diagnosis and management of aspergillosis. Of the numerous recommendations, a few are summarized here. Chest computed tomography as well as bronchoscopy with bronchoalveolar lavage (BAL) in patients with suspicion of pulmonary invasive aspergillosis (IA) are strongly recommended. For diagnosis, direct microscopy, preferably using optical brighteners, histopathology and culture are strongly recommended. Serum and BAL galactomannan measures are recommended as markers for the diagnosis of IA. PCR should be considered in conjunction with other diagnostic tests. Pathogen identification to species complex level is strongly recommended for all clinically relevant Aspergillus isolates; antifungal susceptibility testing should be performed in patients with invasive disease in regions with resistance found in contemporary surveillance programmes. Isavuconazole and voriconazole are the preferred agents for first-line treatment of pulmonary IA, whereas liposomal amphotericin B is moderately supported. Combinations of antifungals as primary treatment options are not recommended. Therapeutic drug monitoring is strongly recommended for patients receiving posaconazole suspension or any form of voriconazole for IA treatment, and in refractory disease, where a personalized approach considering reversal of predisposing factors, switching drug class and surgical intervention is also strongly recommended. Primary prophylaxis with posaconazole is strongly recommended in patients with acute myelogenous leukaemia or myelodysplastic syndrome receiving induction chemotherapy. Secondary prophylaxis is strongly recommended in high-risk patients. We strongly recommend treatment duration based on clinical improvement, degree of immunosuppression and response on imaging.


Asunto(s)
Antifúngicos/uso terapéutico , Aspergilosis/diagnóstico , Aspergilosis/tratamiento farmacológico , Aspergillus/aislamiento & purificación , Manejo de la Enfermedad , Anticuerpos Antifúngicos/sangre , Antifúngicos/farmacología , Aspergilosis/complicaciones , Aspergilosis/inmunología , Aspergillus/efectos de los fármacos , Aspergillus/inmunología , Biopsia/métodos , Lavado Broncoalveolar , Diagnóstico Precoz , Flucitosina/farmacología , Flucitosina/uso terapéutico , Galactosa/análogos & derivados , Humanos , Huésped Inmunocomprometido , Pruebas Inmunológicas , Aspergilosis Pulmonar Invasiva/diagnóstico , Itraconazol/farmacología , Itraconazol/uso terapéutico , Leucemia Mieloide Aguda/complicaciones , Leucemia Mieloide Aguda/terapia , Imagen por Resonancia Magnética , Mananos/análisis , Pruebas de Sensibilidad Microbiana , Síndromes Mielodisplásicos/complicaciones , Síndromes Mielodisplásicos/terapia , Nitrilos/farmacología , Nitrilos/uso terapéutico , Piridinas/farmacología , Piridinas/uso terapéutico , Tomografía Computarizada por Rayos X , Triazoles/farmacología , Triazoles/uso terapéutico , Voriconazol/farmacología , Voriconazol/uso terapéutico
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