Experimental data obtained using three scintillation detectors are analyzed. The characteristics of cosmogenic neutrons in underground experiments their analytic dependences are considered. The ...behavior of background counting rate for the LVD detector for two measuring thresholds (0.5 and 5 MeV) are discussed.
In this paper we show the capabilities of the Large Volume Detector (INFN Gran Sasso National Laboratory) to identify a neutrino burst associated with a supernova explosion, in the absence of an ...“external trigger”, e.g., an optical observation. We describe how the detector trigger and event selection have been optimized for this purpose, and we detail the algorithm used for the on-line burst recognition. The on-line sensitivity of the detector is defined and discussed in terms of supernova distance and
ν
¯
e
intensity at the source.
We report the measurement of the time of flight of ∼17 GeV ν(μ) on the CNGS baseline (732 km) with the Large Volume Detector (LVD) at the Gran Sasso Laboratory. The CERN-SPS accelerator has been ...operated from May 10th to May 24th 2012, with a tightly bunched-beam structure to allow the velocity of neutrinos to be accurately measured on an event-by-event basis. LVD has detected 48 neutrino events, associated with the beam, with a high absolute time accuracy. These events allow us to establish the following limit on the difference between the neutrino speed and the light velocity: -3.8 × 10(-6) < (v(ν)-c)/c < 3.1 × 10(-6) (at 99% C.L.). This value is an order of magnitude lower than previous direct measurements.
Cosmic radiation is a potential additional tool for atmospheric monitoring. High-energy cosmic rays, interacting in the atmosphere, produce secondary particles, the production and propagation of ...which are ruled by the state of the atmosphere. Atmospheric muons carry information on the stratosphere, as its temperature modulates their intensity. Here, we present a comprehensive investigation of the 24-year series of the muon flux recorded underground with the Large Volume Detector in the Gran Sasso Laboratory in Italy. Using advanced spectral-analysis methods, we reveal, in addition to the well-known annual cycle, two significant variations with periods of about four and ten years. These two multiannual components, however, are not present in the series of the so-called effective temperature—an average parameter commonly used to describe the entire atmospheric profile in relationship to the detected muon flux—but we find them in the series of the raw temperatures in the lower-stratospheric levels. We show that the weaker multiannual cycles emerge in the temperature series thanks to the dampening of the dominant annual radiative cycle at these levels, which are affected by higher-frequency variability related to transport and wave processes. We also show that the multiannual variations are not typical only of the Gran Sasso area but are present at large scales throughout the Northern Hemisphere. The analysis of the series of the muon flux also reveals evidence of daily to monthly scale variations, especially during the highly variable winter period. Although such short-term modulations are also found in the series of the effective temperature, we show that the variations of the two series are brought to better agreement when considering only specific layers of the atmosphere depending on the event. The amplitudes of the multiannual variations are significantly larger than those expected based on the temperature modulations. Such differences may be due to acknowledged difficulties of the adopted temperature reanalysis dataset to thoroughly represent long-term variability scales, so that long-term modulations in the raw temperature series and, consequently, in the effective temperature record would result as artificially attenuated. The muon flux therefore may be envisaged as a high time-resolution integrated proxy of lower-stratospheric temperatures.
The throat and belly of both sexes of the common wall lizard Podarcis muralis exhibit a polymorphic coloration with three morphs (white, yellow and red). We documented the occurrence of this ...polymorphism in 11 populations of northern Italy, and investigated the morphometric features of the three morphs in both sexes. The white morph was more frequent (56.6%), while yellow and red morphs accounted for 28.7 and 14.7% of the lizards, respectively. Moreover, the red morphotype was more frequent among males while the white one was more frequent among females. The occurrence of the three morphs varied microgeographically from populations with a higher proportion of white individuals to those where all morphs were more equally represented. The comparisons of morphometry between morphs did not reveal any significant difference among males, while snout-vent length and head height in females increased from the white-throated to the yellow-throated morph, and from the yellow-throated morph to the red-throated one. Possible functions of this polymorphic coloration are discussed.
The evolution of the cosmic ray primary composition in the energy range 106–107 GeV (i.e. the “knee” region) is studied by means of the e.m. and muon data of the Extensive Air Shower EAS-TOP array ...(Campo Imperatore, National Gran Sasso Laboratories). The measurement is performed through: (a) the correlated muon number (Nμ) and shower size (Ne) spectra, and (b) the evolution of the average muon numbers and their distributions as a function of the shower size. From analysis (a) the dominance of helium primaries at the knee, and therefore the possibility that the knee itself is due to a break in their energy spectrum (at EkHe=(3.5±0.3)×106 GeV) are deduced. Concerning analysis (b), the measurement accuracies allow the classification in terms of three mass groups: light (p,He), intermediate (CNO), and heavy (Fe). At primary energies E0≈106 GeV the results are consistent with the extrapolations of the data from direct experiments. In the knee region the obtained evolution of the energy spectra leads to: (i) an average steep spectrum of the light mass group (γp,He>3.1), (ii) a spectrum of the intermediate mass group harder than the one of the light component (γCNO≃2.75, possibly bending at EkCNO≈(6–7)×106 GeV), (iii) a constant slope for the spectrum of the heavy primaries (γFe≃2.3–2.7) consistent with the direct measurements. In the investigated energy range, the average primary mass increases from 〈lnA〉=1.6–1.9 at E0≃1.5×106 GeV to 〈lnA〉=2.8–3.1 at E0≃1.5×107 GeV. The result supports the standard acceleration and propagation models of galactic cosmic rays that predict rigidity dependent cut-offs for the primary spectra of the different nuclei. The uncertainties connected to the hadronic interaction model (QGSJET in CORSIKA) used for the interpretation are discussed.
Ultrasound imaging is a promising technique for studying the reproductive biology of reptiles, but it has yet to be validated for small lizards in field research. This study aimed both at assessing ...the reliability of ultrasound imaging in field research and the measurement of the breeding effort and timing of reproduction in the northern Italian female population of the common wall lizard, Podarcis muralis. To this end, we kept 22 gravid females in captivity in April and June 2010 and used ultrasonography to predict the number of eggs they laid. The following year, we applied the same technique to monitor the breeding performance of females in their natural habitat. We collected 119 females between March and June 2011 and used ultrasonography to evaluate clutch size and egg developmental stage. Our results showed that 20 out of 22 females (91%) laid the exact number of eggs predicted. The field research showed that the percentage of gravid females varied over the season, showing a clear bimodal pattern with two peaks in late April and late May. These peaks corresponded to the first and second clutch depositions, respectively. Furthermore, female common wall lizards reach sexual maturity at a body size of 50–51 mm snout–vent length, at around 2 years of age. Mean clutch size in our population ranged from 2 to 5.5 eggs, with an average of 3.6 eggs. There was a strong positive relationship between clutch and female size, which was only statistically significant in the first deposition. The female lizards in our study were smaller than those in French and central European populations, they reached maturity at 50.9 mm and they laid few eggs. In this paper, we discuss some potential explanations for such differences.
Males and females of Hermann's tortoise (Testudo hermanni) exhibit a conspicuous yellow patch on both their cheeks, whose origin and potential function are totally unknown. In this study, we measured ...the extent and the colour intensity of these patches in 29 male and 19 female tortoises in order to test for sexual difference in these features. In addition, we analysed the relationships between patch features and body condition to investigate the possible function of these ornaments as status signals. We detected symmetric yellow patches in all sampled females, while five males did not show at all the ornament, and two had a yellow patch only on the left cheek. Although head and scale size, as well as RGB values, did not differ between sexes, female patches were significantly larger than those of males. In addition, the extent of cheek patches was correlated to female body condition, suggesting that these ornaments may have evolved as honest signals of quality through sexual selection processes driven by female–female contests over rank or by male mate choice.
The LVD detector, located in the INFN Gran Sasso National Laboratory (Italy), studies supernova neutrinos through the interactions with protons and carbon nuclei in the liquid scintillator and ...interactions with the iron nuclei of the support structure. We investigate the effect of neutrino oscillations in the signal expected in the LVD detector. The MSW effect has been studied in detail for neutrinos travelling through the collapsing star and the Earth. We show that the expected number of events and their energy spectrum are sensitive to the oscillation parameters, in particular to the mass hierarchy and the value of
θ
13
, presently unknown. Finally we discuss the astrophysical uncertainties, showing their importance and comparing it with the effect of neutrino oscillations on the expected signal. We do not discuss in this paper the determination of oscillation parameters from the results of the observations; this task seems to be very difficult until astrophysical uncertainties are significantly reduced.
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