1,231 research outputs found
Neutrino signal from extended Galactic sources in IceCube
We explore the detectability of the neutrino flux from the entire Galactic
Plane or from a part of it with IceCube. We calculate the normalization and the
spectral index of the neutrino power law spectrum from different regions of the
Galactic plane, based on the observed spectral characteristics of the pion
decay gamma-ray diffuse emission observed by the Fermi/LAT telescope in the
energy band above 100 GeV. We compare the neutrino flux calculated in this way
with the sensitivity of IceCube for the detection of extended sources. Assuming
a binned extended source analysis method, we find that the only possible
evidence for neutrino emission for sources located in the Northern hemisphere
is from the Cygnus region after 20 years of exposure. For other parts of the
Galactic Plane even a 20 years exposure with IceCube is not sufficient for the
detection. Taking into account marginal significance of the detectable source
in the Cygnus region, we find a precise position and size of the source region
which optimizes the signal-to-noise ratio for neutrinos. We also calculate the
low-energy threshold above which the neutrino signal could be detected with the
highest signal-to-noise ratio. This calculation of precise source position,
size and energy range, based on the gamma-ray data, could be used to remove the
'trial factor' in the analysis of the real neutrino data of IceCube. We notice
that the diffuse neutrino emission from the inner Galactic Plane in the
Southern Hemisphere is much brighter. A neutrino detector with characteristics
equivalent to IceCube, but placed at the Northern Hemisphere (such as KM3NeT),
would detect several isolated neutrino sources in the Galactic Plane within
just 5 years exposure at 5{\sigma} level. These isolated sources of ~TeV
neutrinos would unambiguously localize sources of cosmic rays which operated
over the last 10 thousand years in the Galaxy.[abridged]Comment: submitted to A&
An exploration of hadronic interactions in blazars using IceCube
Context: Hadronic models, involving matter (proton or nuclei) acceleration in
blazar jets, imply high energy photon and neutrino emissions due to
interactions of high-energy protons with matter and/or radiation in the source
environment. Aims: This paper shows that the sensitivity of the IceCube
neutrino telescope in its 40-string configuration (IC-40) is already at the
level of constraining the parameter space of purely hadronic scenarios of
activity of blazars. Methods: Assuming that the entire source power originates
from hadronic interactions, and assuming that the models describe the data, we
estimate the expected neutrino flux from blazars based on the observed
gamma-ray flux by Fermi, simultaneously with IC-40 observations. We consider
two cases separately to keep the number of constrainable parameters at an
acceptable level: proton-proton or proton-gamma interactions are dominant.
Comparing the IC-40 sensitivity to the neutrino flux expected from some of the
brightest blazars, we constrain model parameters characterizing the parent
high-energy proton spectrum. Results: We find that when pp interactions
dominate, some constraints on the primary proton spectrum can be imposed. For
instance, for the tightest constrained source 3C 454.3, the very high energy
part of the spectra of blazars is constrained to be harder than E^-2 with
cut-off energies in the range of Ecut >10^18 eV. When interactions of
high-energy protons on soft photon fields dominate, we can find similarly tight
constraints on the proton spectrum parameters. [abridged]Comment: accepted for publication in A&
Results from the Blazar Monitoring Campaign at the Whipple 10m Gamma-ray Telescope
In September 2005, the observing program of the Whipple 10 m gamma-ray
telescope was redefined to be dedicated almost exclusively to AGN monitoring.
Since then the five Northern Hemisphere blazars that had already been detected
at Whipple are monitored routinely each night that they are visible. Thanks to
the efforts of a large number of multiwavelength collaborators, the first year
of this program has been very successful. We report here on the analysis of
Markarian 421 observations taken from November, 2005 to May, 2006 in the
gamma-ray, X-ray, optical and radio bands.Comment: 4 pages; contribution to the 30th International Cosmic Ray
Conference, Merida, Mexico, July 200
Pediatric endoscopic pilonidal sinus treatment (PEPSiT): what we learned after a 3-year experience in the pediatric population
This paper aimed to report a multi-institutional 3-year experience with pediatric endoscopic pilonidal sinus treatment (PEPSiT) and describe tips and tricks of the technique. We retrospectively reviewed all patients < 18 years, with primary or recurrent pilonidal sinus disease (PSD), undergoing PEPSiT in the period 2017–2020. All patients received pre-operative laser therapy, PEPSiT and post-operative dressing and laser therapy. Success rate, healing rate/time, post-operative management, short- and long-term outcome and patient satisfaction were assessed. A total of 152 patients (98 boys) were included. Median patient’s age was 17.1 years. Fifteen/152 patients (9.8%) presented a recurrent PSD. All patients resumed full daily activities 1 day after surgery. The post-operative course was painless in 100% of patients (median VAS pain score < 2/10). Patient satisfaction was excellent (median score 4.8). The median follow-up was 12.8 months (range 1–36). Complete healing in 8 weeks was achieved in 145/152 (95.4%) and the median healing time was 24.6 days (range 16–31). We reported post-operatively immediate Clavien grade 2 complications (3 oedema, 2 burns) in 5/152 (3.3%) and delayed Clavien grade 2 complications (3 granulomas, 8 wound infections) in 11/152 (7.2%). Disease recurrence occurred in 7/152 (4.6%), who were re-operated using PEPSiT. PEPSiT should be considered the standard of care for surgical treatment of PSD in children and teenagers. PEPSiT is technically easy, with short and painless post-operative course and low recurrence rate (4.6%). Standardized treatment protocol, correct patient enrollment and information, and intensive follow-up are key points for the success of the procedure
A simulation code to assist designing space missions of the Airwatch type
The design of an Airwatch type space mission can greatly benefit from a flexible simulation code for establishing the values of the main parameters of the experiment. We present here a code written for this purpose. The cosmic ray primary spectrum at very high energies, the atmosphere modelling, the fluorescence yield, the photon propagation and the detector response are taken into account in order to optimize the fundamental design parameters of the experiment, namely orbit height, field of view, mirror radius, number of pixels of the focal plane, threshold of photo-detection. The optimization criterion will be to maximize counting rates versus mission cost, which imposes limits both on weight and power consumption. Preliminary results on signals with changing energy and zenith angle of incident particles are shown
SENSE: A comparison of photon detection efficiency and optical crosstalk of various SiPM devices
This paper describes a comparison of photon detection efficiency and optical
crosstalk measurements performed by three partners: Geneva University, Catania
Observatory and Nagoya University. The measurements were compared for three
different SiPM devices with different active areas: from 9 up to 93.6
produced by Hamamatsu. The objective of this work is to establish the
measurements and analysis procedures for calculating the main SiPM parameters
and their precision. This work was done in the scope of SENSE project which
aims to build roadmap for the last developments in field of sensors for low
light level detection
Sella turcica and craniofacial morphology in patients with palatally displaced canines: a retrospective study
Background: The aim of the study was to evaluate the sella and craniofacial morphological features in growing patients with palatally displaced canines compared to controls.
Materials and methods: Twenty-two subjects with palatally displaced canines were retrospectively selected and compared to 22 controls matched for age and gender. Lateral cephalograms were collected and sagittal and vertical cephalometric variables were measured, together with sella interclinoid distance, sella depth, and sella diameter. The independent samples T-test or Mann-Whitney U-test were used to compare all the variables between the two groups. A Pearson correlation was computed for the craniofacial and sella variables that differed significantly (p < 0.05) between the groups.
Results: Patients with palatally displaced canines showed a smaller interclinoid distance and a greater SNA angle than control subjects. The interclinoid distance and the SNA angle were negatively correlated (–0.52, p = 0.017) in the experimental group.
Conclusions: Growing patients with palatally displaced canines had smaller sella interclinoid distances and a greater SNA angle than control subjects
A new calculation of atmospheric neutrino flux: the FLUKA approach.
Abstract Preliminary results from a full 3-D calculation of atmospheric neutrino fluxes using the FLUKA interaction model are presented and compared to previous existing calculations. This effort is motivated mainly by the 3-D capability and the satisfactory degree of accuracy of the hadron-nucleus models embedded in the FLUKA code. Here we show examples of benchmarking tests of the model with cosmic ray experiment results. A comparison of our calculation of the atmospheric neutrino flux with that of the Bartol group, for E ν > 1 GeV, is presented
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