1,672 research outputs found
Neutrino search from {\gamma}-ray bursts during the prompt and X-ray afterglow phases using 10 years of IceCube public data
Neutrino emission from gamma-ray bursts (GRBs) has been sought for a long
time, and stringent limits on the most accredited GRB emission models have been
obtained from IceCube. Multi-wavelength GRB observations of the last decades
improved our knowledge of the GRB emission parameters, such as the Lorentz
factor and the luminosity, which can vary from one GRB to another by several
orders of magnitude. Empirical correlations among such parameters have been
identified during the prompt phase, with direct implications on GRB models. In
this work, we use the PSLab open-access code, developed for IceCube data
analyses, to search for individual neutrino emission from the prompt and
afterglow phases of selected GRBs, and for stacking emission from the ensemble
of such GRBs. For the afterglow phase, we focus in particular on GRBs with
X-ray flares and plateaus. While past stacking searches assumed the same GRB
fluence at Earth, we present a stacking scheme based on physically motivated
GRB weights. Moreover, we conceive a new methodology for the prompt phase that
uses the empirical correlations to infer the GRB luminosity and Lorentz factor,
when redshift measurements are not available. We do not observe any significant
neutrino excess. Hence, we set constraints on the GRB neutrino fluxes and on
relevant GRB parameters, including the magnetic field in the jet. Notably, the
baryon loading is found to be <10 for typical GRB prompts, thus disfavoring a
baryonic-dominated origin of the GRB ejecta.Comment: Submitted for publication to A&A. Comments are welcom
Soil, humipedon, forest life and management
In recent years, three sections (Humipedon, Copedon and Lithopedon) were recognized in the soil profile. It was then possible to link the first and most biologically active section to the characteristics of the environment and soil genesis. In particular, it is now possible to distinguish organic horizons, mainly produced by arthropods and enchytraeids in cold and acidic or dry and arid environments, from organo-mineral horizons produced by earthworms in more temperate and mesotrophic environments. Each set of horizons can be associated with a humus system or form, with important implications for forestry. Anecic/endogeic earthworms and Mull or Amphi systems are more abundant in the early and late stages of sylvogenesis; by completely recycling litter, earthworms accelerate the availability of organic and inorganic soil nutrients to roots and pedofauna. On the other hand, arthropods and Moder or Tangel systems characterize the intermediate stages of sylvogenesis, where thickening in the organic horizons and the parallel impoverishment/reduction in the underlying organo-mineral horizons are observed. Recognizing the humus system at the right spatial and temporal scale is crucial for the biological management of a forest. This article includes a data review, new data from a doctoral thesis, and recent comparisons of Italian and French investigation
Prevalence of tobacco smoking and electronic cigarette use among adolescents in Italy: Global Youth Tobacco Surveys (GYTS), 2010, 2014, 2018
Effect of black soldier fly (Hermetia illucens) meal in sturgeon (Acipenser baerii) juvenils feeds: preliminary results.
A bright megaelectronvolt emission line in -ray burst GRB 221009A
The highly variable and energetic pulsed emission of a long gamma-ray burst
(GRB) is thought to originate from local, rapid dissipation of kinetic or
magnetic energy within an ultra-relativistic jet launched by a newborn compact
object, formed during the collapse of a massive star. The spectra of GRB pulses
are best modelled by power-law segments, indicating the dominance of
non-thermal radiation processes. Spectral lines in the X-ray and soft
-ray regime for the afterglow have been searched for intensively, but
never confirmed. No line features ever been identified in the high energy
prompt emission. Here we report the discovery of a highly significant () narrow emission feature at around MeV in the brightest ever GRB
221009A. By modelling its profile with a Gaussian, we find a roughly constant
width MeV and temporal evolution both in energy ( MeV
to MeV) and luminosity ( erg/s to erg/s) over 80 seconds. We interpret this feature as a blue-shifted
annihilation line of relatively cold ()
electron-positron pairs, which could have formed within the jet region where
the brightest pulses of the GRB were produced. A detailed understanding of the
conditions that can give rise to such a feature could shed light on the so far
poorly understood GRB jet properties and energy dissipation mechanism.Comment: Submitte
Running Effects on Lepton Mixing Angles in Flavour Models with Type I Seesaw
We study renormalization group running effects on neutrino mixing patterns
when a (type I) seesaw model is implemented by suitable flavour symmetries. We
are particularly interested in mass-independent mixing patterns to which the
widely studied tribimaximal mixing pattern belongs. In this class of flavour
models, the running contribution from neutrino Yukawa coupling, which is
generally dominant at energies above the seesaw threshold, can be absorbed by a
small shift on neutrino mass eigenvalues leaving mixing angles unchanged.
Consequently, in the whole running energy range, the change in mixing angles is
due to the contribution coming from charged lepton sector. Subsequently, we
analyze in detail these effects in an explicit flavour model for tribimaximal
neutrino mixing based on an A4 discrete symmetry group. We find that for
normally ordered light neutrinos, the tribimaximal prediction is essentially
stable under renormalization group evolution. On the other hand, in the case of
inverted hierarchy, the deviation of the solar angle from its TB value can be
large depending on mass degeneracy.Comment: 36 pages, 4 figures; few references added and minor correction
Notulae to the Italian alien vascular flora: 11
In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates published elsewhere are provided as Suppl. material 1
Hepatitis D double reflex testing of all hepatitis B carriers in low-HBV- and high-HBV/HDV-prevalence countries
Hepatitis D virus (HDV) infection occurs as a coinfection with hepatitis B and increases the risk of hepatocellular carcinoma, decompensated cirrhosis, and mortality compared to hepatitis B virus (HBV) monoinfection. Reliable estimates of the prevalence of HDV infection and disease burden are essential to formulate strategies to find coinfected individuals more effectively and efficiently. The global prevalence of HBV infections was estimated to be 262,240,000 in 2021. Only 1,994,000 of the HBV infections were newly diagnosed in 2021, with more than half of the new diagnoses made in China. Our initial estimates indicated a much lower prevalence of HDV antibody (anti-HDV) and HDV RNA positivity than previously reported in published studies. Accurate estimates of HDV prevalence are needed. The most effective method to generate estimates of the prevalence of anti-HDV and HDV RNA positivity and to find undiagnosed individuals at the national level is to implement double reflex testing. This requires anti-HDV testing of all hepatitis B surface antigen-positive individuals and HDV RNA testing of all anti-HDV-positive individuals. This strategy is manageable for healthcare systems since the number of newly diagnosed HBV cases is low. At the global level, a comprehensive HDV screening strategy would require only 1,994,000 HDV antibody tests and less than 89,000 HDV PCR tests. Double reflex testing is the preferred strategy in countries with a low prevalence of HBV and those with a high prevalence of both HBV and HDV. For example, in the European Union and North America only 35,000 and 22,000 cases, respectively, will require anti-HDV testing annually
The commissioning of the CUORE experiment: the mini-tower run
CUORE is a ton-scale experiment approaching the data taking phase in Gran Sasso National Laboratory. Its primary goal is to search for the neutrinoless double-beta decay in 130Te using 988 crystals of tellurim dioxide. The crystals are operated as bolometers at about 10 mK taking advantage of one of the largest dilution cryostat ever built. Concluded in March 2016, the cryostat commissioning consisted in a sequence of cool down runs each one integrating new parts of the apparatus. The last run was performed with the fully configured cryostat and the thermal load at 4 K reached the impressive mass of about 14 tons. During that run the base temperature of 6.3 mK was reached and maintained for more than 70 days. An array of 8 crystals, called mini-tower, was used to check bolometers operation, readout electronics and DAQ. Results will be presented in terms of cooling power, electronic noise, energy resolution and preliminary background measurements
Results from the Cuore Experiment
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers, each of them made of 52 crystals. The construction of the experiment was completed in August 2016 and the data taking started in spring 2017 after a period of commissioning and tests. In this work we present the neutrinoless double beta decay results of CUORE from examining a total TeO2 exposure of 86.3kg yr, characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts/ (keV kg yr). In this physics run, CUORE placed a lower limit on the decay half- life of neutrinoless double beta decay of 130Te > 1.3.1025 yr (90% C. L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130Te 2vo3p decay with a resulting half- life of T2 2. [7.9 :- 0.1 (stat.) :- 0.2 (syst.)] x 10(20) yr which is the most precise measurement of the half- life and compatible with previous results
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