A novel algorithm developed within muon radiography to localize objects or cavities hidden inside large material volumes was recently proposed by some of the authors (Bonechi et al. 2015 J. Instrum. ...10, P02003 (doi:10.1088/1748-0221/10/02/P02003)). The algorithm, based on muon back projection, helps to estimate the three-dimensional position and the transverse extension of detected objects without the need for measurements from different points of view, which would be required to make a triangulation. This algorithm can now be tested owing to the availability of real data collected both in laboratory tests and from real-world measurements. The methodology and some test results are presented in this paper.
This article is part of the Theo Murphy meeting issue ‘Cosmic-ray muography’.
It is known that the 5%-10% of adults infected with hepatitis B virus (HBV) develop a chronic infection and that HBV infection acquired at birth by an hepatitis B surface antigen (HBsAg)/hepatitis B ..."e" antigen (HBeAg)-positive mother almost invariably leads to chronic infection. Little information is, however, available about the risk of HBV infection acquired in childhood becoming chronic. We have, therefore, studied the chronicity rate of HBV infection in the families of 60 consecutive HBsAg-positive chronic carrier children. Of parents 81.5% and 78.6% of children showed serological evidence of past or ongoing HBV infection. The chronicity rate was significantly higher among children (73.4%) than parents (35.6%). Such a high chronicity rate in these children was not correlated with vertical transmission, since this was reported in only 1.7% of them. It is noteworthy that the chronicity rate of HBV infection was not significantly different between children of HBsAg-positive mothers and those in whom infection must have been horizontally transmitted because their mothers were HBsAg-negative. Although the families studied represent a selected sample and the role of genetic factors could not be excluded, our results seem to show that the most important factor in determining the outcome of infection is the acquisition of hepatitis B during childhood.
We discuss the methodological aspects related to the evaluation of turn-over and up-down sizing as indicators of work-related stress, in complex organizations like a university hospital. To estimate ...the active workers population we developed an algorithm which integrated several administrative databases. The indicators were standardized to take into account some potential confounders (age, sex, work seniority) when considering different hospital structures and job mansions. Main advantages of our method include flexibility in the choice of the analysis detail (hospital units, job mansions, a combination of both) and the possibility to describe over-time trends to measure the success of preventive strategies.
Alcohol consumption during pregnancy is a significant public health problem and is an established cause of serious birth defects and developmental delay collectively described as fetal alcohol ...syndrome (FAS). FAS is caused by congenital alcohol-induced damages and is a cause of mental retardation. It is characterised by facial abnormalities and growth deficiency. Infants affected by the syndrome show intellectual impairment, and difficulties in learning, memory, problem-solving, and attention as well as experiencing additional problems with mental health and social interactions. However, an absence of the characteristic facial defects and growth deficiency may result in a failure to identify children with prenatal alcohol exposure, which can further present as alcohol-related neurodevelopment disorder (ARND) or alcohol-related birth defects (ARBD). Estimates of prevalence of FAS in U.S.A. range between 0.3 to 2.2 per 1,000 live births, but much higher rates occurring in some communities. Harmonisation of the methodology used for epidemiological studies, with research activities that establishes real baseline prevalence of FAS and identification of women who are at highest risk of bearing a FAS-affected child, are an essential prerequisite to prevention. In addition, it is essential to assess different FAS preventive approaches through carefully controlled studies. Universal, selected, and indicated preventive strategies have been identified, targeting different kind of populations. Since FAS and other adverse effects of drinking during pregnancy are theoretically completely preventable, it is vital to make more efforts to improve the application of the most appropriate interventions. Although in Italy alcohol consumption has constantly increased, mainly amongst the young (including women of childbearing age), knowledge on FAS and alcohol-related effects is completely lacking. Because of the high cost for care of individuals with this syndrome, it is essential to apply appropriate interventions to prevent this problem.
The MUon RAdiography of VESuvius (MURAVES) project aims at the study of the summital cone of Mt. Vesuvius, an active and hazardous volcano near Naples, Italy. A detailed Monte Carlo simulation ...framework is necessary in order to investigate the effects of the experimental constraints and to perform comparisons with the actual observations. Our Monte Carlo setup combines a variety of Monte Carlo programs that address different aspects of cosmic muon simulation, from muon generation in the Earth's upper atmosphere to the response of the detector, including the interactions with the material of the volcano. We will elaborate on the rationale for our technical choices, including trade-off between speed and accuracy, and on the lessons learned, which are of general interest for similar use cases in muon radiography.
The MUon RAdiography of VESuvius (MURAVES) project aims at the study of the summital cone of Mt. Vesuvius, an active volcano near Naples (Italy), by measuring its density profile through muon flux ...attenuation. Its data, combined with those from gravimetric and seismic measurement campaigns, will be used for better defining the volcanic plug at the bottom of the crater. We report on the development of an end-to-end simulation framework, in order to perform accurate investigations of the effects of the experimental constraints and to compare simulations, under various model hypotheses, with the actual observations. The detector simulation setup is developed using GEANT4 and a study of cosmic particle generators has been conducted to identify the most suitable one for our simulation framework. To mimic the real data, GEANT4 raw hits are converted to clusters through a simulated digitization: energy deposits are first summed per scintillator bar, and then converted to number of photoelectrons with a data-driven procedure. This is followed by the same clustering algorithm and same tracking code as in real data. We also report on the study of muon transport through rock using PUMAS and GEANT4. In this paper we elaborate on the rationale for our technical choices, including trade-off between speed and accuracy. The developments reported here are of general interest in muon radiography and can be applied in similar cases.
The MURAVES experiment aims at the muographic imaging of the internal structure of the summit of Mt. Vesuvius, exploiting muons produced by cosmic rays. Though presently quiescent, the volcano ...carries a dramatic hazard in its highly populated surroundings. The challenging measurement of the rock density distribution in its summit by muography, in conjunction with data from other geophysical techniques, can help the modeling of possible eruptive dynamics. The MURAVES apparatus consists of an array of three independent and identical muon trackers, with a total sensitive area of 3 square meters. In each tracker, a sequence of 4 XY tracking planes made of plastic scintillators is complemented by a 60 cm thick lead wall inserted between the two downstream planes to improve rejection of background from low energy muons. The apparatus is currently acquiring data. Preliminary results from the analysis of a first data sample are presented.
