2,228 research outputs found
How isotropic can the UHECR flux be?
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
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
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
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
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
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
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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