2,228 research outputs found

    How isotropic can the UHECR flux be?

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    Modern observatories of ultra-high energy cosmic rays (UHECR) have collected over 10^4 events with energies above 10 EeV, whose arrival directions appear to be nearly isotropically distributed. On the other hand, the distribution of matter in the nearby Universe -- and, therefore, presumably also that of UHECR sources -- is not homogeneous. This is expected to leave an imprint on the angular distribution of UHECR arrival directions, though deflections by cosmic magnetic fields can confound the picture. In this work, we investigate quantitatively this apparent inconsistency. To this end we study observables sensitive to UHECR source inhomogeneities but robust to uncertainties on magnetic fields and the UHECR mass composition. We show, in a rather model-independent way, that if the source distribution tracks the overall matter distribution, the arrival directions at energies above 30 EeV should exhibit a sizeable dipole and quadrupole anisotropy, detectable by UHECR observatories in the very near future. Were it not the case, one would have to seriously reconsider the present understanding of cosmic magnetic fields and/or the UHECR composition. Also, we show that the lack of a strong quadrupole moment above 10 EeV in the current data already disfavours a pure proton composition, and that in the very near future measurements of the dipole and quadrupole moment above 60 EeV will be able to provide evidence about the UHECR mass composition at those energies.Comment: 9 pages, 8 figures; accepted versio

    Cosmogenic neutrinos and gamma-rays and the redshift evolution of UHECR sources

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    If ultra-high-energy cosmic rays (UHECRs) have extragalactic origins, as is widely assumed to be the case at least for the majority of cosmic rays with energies above a few EeV, secondary neutrinos and photons can be expected to be produced during the propagation of UHECRs through intergalactic space via interactions with cosmic background photons. The fluxes of such secondary particles are strongly dependent on the redshift evolution of the emissivity (number density times luminosity) of UHECR sources. We show how cosmic rays, neutrinos, and gamma rays can potentially provide complementary information about UHECR source evolution.Comment: 6 pages, 3 figures; published in the proceedings of the Neutrino Oscillation Workshop, 4-11 September 2016, Otranto, Ital

    Sildenafil improves clinical and functional status of an elderly postmenopausal female with ‘out of proportion’ PH associated with left heart disease

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    We report a case of an elderly woman with heart failure with preserved ejection fraction and pulmonary hypertension (HFpEF-PH), refractory to conventional therapy for left heart failure and successfully treated by sildenafil

    Reconstructing particles in jets using set transformer and hypergraph prediction networks

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    The task of reconstructing particles from low-level detector response data to predict the set of final state particles in collision events represents a set-to-set prediction task requiring the use of multiple features and their correlations in the input data. We deploy three separate set-to-set neural network architectures to reconstruct particles in events containing a single jet in a fully-simulated calorimeter. Performance is evaluated in terms of particle reconstruction quality, properties regression, and jet-level metrics. The results demonstrate that such a high dimensional end-to-end approach succeeds in surpassing basic parametric approaches in disentangling individual neutral particles inside of jets and optimizing the use of complementary detector information. In particular, the performance comparison favors a novel architecture based on learning hypergraph structure, HGPflow, which benefits from a physically-interpretable approach to particle reconstruction.Comment: 17 pages, 21 figure

    Astrophysical interpretation of Pierre Auger Observatory measurements of the UHECR energy spectrum and mass composition

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    We present a combined fit of a simple astrophysical model of UHECR sources to both the energy spectrum and mass composition data measured by the Pierre Auger Observatory. The fit has been performed for energies above 5 EeV, i.e. the region of the all-particle spectrum above the so-called "ankle" feature. The astrophysical model we adopted consists of identical sources uniformly distributed in a comoving volume, where nuclei are accelerated with a rigidity-dependent mechanism. The fit results suggest sources characterized by relatively low maximum injection energies and hard spectral indices. The impact of various systematic uncertainties on the above result is discussed.Comment: 4 pages, 1 figure, 1 table; published in the proceedings of the 6th Roma International Conference on Astroparticle Physics (RICAP16), 21-24 June 2016, Frascati (Rome), Ital

    Fluorescence-Guided Surgery in Glioblastoma: 5-ALA, SF or Both? Differences between Fluorescent Dyes in 99 Consecutive Cases

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    Background: Glioblastoma (GBM) is the most common primary brain tumor. The extent of resection (EOR) has been claimed as one of the most important prognostic factors. Fluorescent dyes aid surgeons in detecting a tumor’s borders. 5-aminolevulinic acid (5-ALA) and sodium fluorescein (SF) are the most used. Only a few studies have directly compared these two fluorophores. Methods: A single center retrospective analysis of patients treated for GBM in the period between January 2018 and January 2021 was built to find any differences in terms of EOR, Karnofsky Performance Status (KPS), and overall survival (OS) on the use of 5-ALA, SF, or both. Results: Overall, 99 patients affected by isocitrate dehydrogenase (IDH) wild-type Glioblastoma were included. 5-ALA was administered to 40 patients, SF to 44, and both to 15. No statistically significant associations were identified between the fluorophore and EOR (p = 0.783) or postoperative KPS (p = 0.270). Survival analyses did not show a selective advantage for the use of a given fluorophore (p = 0.184), although there appears to be an advantageous trend associated with the concomitant use of both dyes, particularly after stratification by MGMT (p = 0.071). Conclusions: 5-Ala and SF are equally useful in achieving gross total resection of the enhancing tumor volume. The combination of both fluorophores could lead to an OS advantage

    Prognostic role of neoplastic markers in Takotsubo syndrome

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    Takotsubo syndrome (TTS) is an acute heart failure syndrome with significant rates of in and out-of-hospital mayor cardiac adverse events (MACE). To evaluate the possible role of neoplastic biomarkers [CA-15.3, CA-19.9 and Carcinoembryonic Antigen (CEA)] as prognostic marker at short- and long-term follow-up in subjects with TTS. Ninety consecutive subjects with TTS were enrolled and followed for a median of 3 years. Circulating levels of CA-15.3, CA-19.9 and CEA were evaluated at admission, after 72 h and at discharge. Incidence of MACE during hospitalization and follow-up were recorded. Forty-three (46%) patients experienced MACE during hospitalization. These patients had increased admission levels of CEA (4.3 ± 6.2 vs. 2.2 ± 1.5 ng/mL, p = 0.03). CEA levels were higher in subjects with in-hospital MACE. At long term follow-up, CEA and CA-19.9 levels were associated with increased risk of death (log rank p < 0.01, HR = 5.3, 95% CI 1.9-14.8, HR = 7.8 95% CI 2.4-25.1, respectively, p < 0.01). At multivariable analysis levels higher than median of CEA, CA-19.9 or both were independent predictors of death at long term (Log-Rank p < 0.01). Having both CEA and CA-19.9 levels above median (> 2 ng/mL, > 8 UI/mL respectively) was associated with an increased risk of mortality of 11.8 (95% CI 2.6-52.5, p = 0.001) at follow up. Increased CEA and CA-19.9 serum levels are associated with higher risk of death at long-term follow up in patients with TTS. CEA serum levels are correlated with in-hospital MACE
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