The NEMO Collaboration installed and operated an underwater detector including prototypes of the critical elements of a possible underwater km(3) neutrino telescope: a four-floor tower (called Mini-Tower) and a Junction Box. The detector was developed to test some of the main systems of the km(3) detector, including the data transmission, the power distribution, the timing calibration and the acoustic positioning systems as well as to verify the capabilities of a single tridimensional detection structure to reconstruct muon tracks. We present results of the analysis of the data collected with the NEMO MiniTower. The position of photomultiplier tubes (PMTs) is determined through the acoustic position system. Signals detected with PMTs are used to reconstruct the tracks of atmospheric muons. The angular distribution of atmospheric muons was measured and results compared to Monte Carlo simulations. (C) 2010 Elsevier B.V. All rights reserved
A recent analysis of the Fermi Large Area Telescope data provided evidence for a high-intensity emission of high-energy gamma rays with a E −2 spectrum from two large areas, spanning 50 • above and below the Galactic centre (the "Fermi bubbles"). A hadronic mechanism was proposed for this gamma-ray emission making the Fermi bubbles promising source candidates of high-energy neutrino emission. In this work Monte Carlo simulations regarding the detectability of high-energy neutrinos from the Fermi bubbles 4 with the future multi-km 3 neutrino telescope KM3NeT in the Mediterranean Sea are presented. Under the hypothesis that the gamma-ray emission is completely due to hadronic processes, the results indicate that neutrinos from the bubbles could be discovered in about one year of operation, for a neutrino spectrum with a cutoff at 100 TeV and a detector with about 6 km 3 of instrumented volume. The effect of a possible lower cutoff is also considered.
Within the framework of the EU Life+ project named LIFE09 NAT/IT/000190 ARION, a permanent automated real-time passive acoustic monitoring system for the improvement of the conservation status of the transient and resident population of bottlenose dolphin (Tursiops truncatus) has been implemented and installed in the Portofino Marine Protected Area (MPA), Ligurian Sea. The system is able to detect the simultaneous presence of dolphins and boats in the area and to give their position in real time. This information is used to prevent collisions by diffusing warning messages to all the categories involved (tourists, professional fishermen and so on). The system consists of two gps-synchronized acoustic units, based on a particular type of marine buoy (elastic beacon), deployed about 1 km off the Portofino headland. Each one is equipped with a four-hydrophone array and an onboard acquisition system which can record the typical social communication whistles emitted by the dolphins and the sound emitted by boat engines. Signals are pre-filtered, digitized and then broadcast to the ground station via wi-fi. The raw data are elaborated to get the direction of the acoustic target to each unit, and hence the position of dolphins and boats in real time by triangulation.
Abstract. The interplay of bio-aerosol dispersion and impact,
meteorology, and air quality is gaining increasing interest in the wide spectrum
of atmospheric sciences. Experiments conducted inside confined artificial
environments, such as atmospheric simulation chambers (ASCs), where
atmospheric conditions and composition are controlled, can provide valuable
information on bio-aerosol viability, dispersion, and impact. We focus here
on the reproducible aerosolization and injection of viable microorganisms
into an ASC, the first and crucial step of any experimental protocol to
expose bio-aerosols to different atmospheric conditions. We compare the
performance of three nebulizers specifically designed for bio-aerosol
applications: the Collison nebulizer, the Blaustein Atomizing Modules (BLAM), and the Sparging Liquid Aerosol Generator (SLAG), all manufactured and commercialized by CH TECHNOLOGIES. The comparison refers to operating
conditions and the concentration of viable bacteria at the nebulizer outlet,
with the final goal being to measure the reproducibility of the nebulization
procedures and assess their application in experiments inside ASCs. A typical
bacterial test model, Escherichia coli (ATCC® 25922™), was
selected for such characterization. Bacteria suspensions with a
concentration around 108 CFU mL−1 were first aerosolized at
different air pressures and collected by a liquid impinger to obtain a
correlation curve between airflow and nebulized bacteria for each
generator. Afterwards, bacteria were aerosolized inside the atmospheric
simulation chamber ChAMBRe (Chamber for Aerosol Modelling and Bio-aerosol
Research) to measure the reproducibility of the whole procedure. An overall
reproducibility of 11 % (i.e., standard deviation of the results obtained with the three nebulizers) was obtained with each nebulizer through a set of
baseline experiments.
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