Context. Finding the sources responsible for the hydrogen reionization is one of the most pressing issues in observational cosmology. Bright quasi-stellar objects (QSOs) are known to ionize their ...surrounding neighborhood, but they are too few to ensure the required HI ionizing background. A significant contribution by faint active galactic nuclei (AGNs), however, could solve the problem, as recently advocated on the basis of a relatively large space density of faint active nuclei at z > 4. Aims. This work is part of a long-term project aimed at measuring the Lyman Continuum escape fraction for a large sample of AGNs at z ~ 4 down to an absolute magnitude of M1450 ~ −23. We have carried out an exploratory spectroscopic program to measure the HI ionizing emission of 16 faint AGNs spanning a broad U − I color interval, with I ~ 21–23, and 3.6 < z < 4.2. These AGNs are three magnitudes fainter than the typical SDSS QSOs (M1450 ≲−26) which are known to ionize their surrounding IGM at z ≳ 4. Methods. We acquired deep spectra of these faint AGNs with spectrographs available at the VLT, LBT, and Magellan telescopes, that is, FORS2, MODS1-2, and LDSS3, respectively. The emission in the Lyman Continuum region, close to 900 Å rest frame, has been detected with a signal to noise ratio of ~10–120 for all 16 AGNs. The flux ratio between the 900 Å rest-frame region and 930 Å provides a robust estimate of the escape fraction of HI ionizing photons. Results. We have found that the Lyman Continuum escape fraction is between 44 and 100% for all the observed faint AGNs, with a mean value of 74% at 3.6 < z < 4.2 and − 25.1 ≲ M1450 ≲−23.3, in agreement with the value found in the literature for much brighter QSOs (M1450 ≲−26) at the same redshifts. The Lyman Continuum escape fraction of our faint AGNs does not show any dependence on the absolute luminosities or on the observed U − I colors of the objects. Assuming that the Lyman Continuum escape fraction remains close to ~75% down to M1450 ~ − 18, we find that the AGN population can provide between 16 and 73% (depending on the adopted luminosity function) of the whole ionizing UV background at z ~ 4, measured through the Lyman forest. This contribution increases to 25–100% if other determinations of the ionizing UV background are adopted from the recent literature. Conclusions. Extrapolating these results to z ~ 5–7, there are possible indications that bright QSOs and faint AGNs can provide a significant contribution to the reionization of the Universe, if their space density is high at M1450 ~ −23.
The new technologies are changing every aspect of our life, socially and workwise. In the same way, digital tools are becoming increasingly important to protect, preserve, and valorise cultural ...heritage. The digitalization of the archive’s documents and ancient books, the realisation of augmented reality apps for museums, or even the creation of virtual realities set in cultural or landscape environments that are protected or not open to visitors, are examples of the use of the new technology in the field of cultural heritage.In this context, the projects “Cosmic Pages” and “Touch the Sky” were developed. One of the main goals of these projects is the realisation of the virtual exhibition “Look up!”. It is an effective virtual tool aimed at enhancing and giving maximum dissemination of the collection of the stellar atlases, cometographies and selenographies preserved in the Observatories of the Italian National Institute for Astrophysics. This virtual exhibit was conceived and realised allowing the visitors to discover, explore, and understand how our knowledge of the cosmos, the Moon and the planets have evolved and changed with the time. Using the most advanced technologies, virtual reality, 3D models, videos etc., visitors can explore the scientific and cultural contents of the stellar and cartographic atlases.
Abstract Objective The use of benzodiazepines (BDZs) represents a critical issue since a long-term treatment may lead to dependence. This study aimed at evaluating socio-demographic and clinical ...characteristics of BZD long-term users who followed a detoxification programme at a tertiary care centre. Method Two hundred-five inpatients were evaluated. Socio-demographic (e.g., gender, age, education) and clinical information (e.g., BZD used, dose, reason of prescription) were collected. BZDs dose was standardized as diazepam dose equivalents and was compared via the Defined Daily Dose (DDD). Chi-square, Fisher test, ANOVA and Bonferroni analyses were performed. Results Females were more frequently BDZ long-term users than males. Hypnotics BZDs were frequently prescribed for problems different from sleep disturbances. Lorazepam, alprazolam, and lormetazepam were the most prescribed drugs. Lorazepam was more frequently used by males, consumed for a long period, in pills, and prescribed for anxiety. Lormetazepam was more frequently consumed by females with a high school education, having a psychiatric disorder, taken in drops and prescribed for insomnia. Lormetazepam had the highest DDD. Conclusion A specific profile of BZD long-term user seems to exist and presents different socio-demographic and clinical characteristics according to the benzodiazepine taken into account.
In this paper, the development of efficient protective clothing against nanoparticulate aerosols is presented. Nanofibrous mats of polyamide 6 (PA6) were deposited onto a nonwoven viscose substrate ...by electrospinning technique. The influence of electrospinning parameters, including solution concentration, viscosity, and conductivity, was studied for the production of nonwovens with controlled fiber diameter showing a size distribution ranging from 66 to 195 nm. By varying several process parameters, textiles with different thickness of the nanofiber layer and thus air permeability were obtained. A hot-press lamination process using a thermoplastic resin as glue was applied to improve the adhesion of the nanofiber layer onto the textile support. After 1500 cycles of repeated compression and torsion, the nanofiber layer was still firmly attached to the support, while mechanical damage is visible in some areas. The penetration of NaCl particles with diameter ranging from 15 to 300 nm through the electrospun textiles was found to be strongly dependent on nanofiber layer thickness. A really thin nanofiber coating provides up to 80% retention of 20 nm size particles and over 50% retention of 200 nm size nanoparticles. Increasing the thickness of the nanofiber mat, the filtration efficiency was increased to over 99% along the whole nanoparticle range. The results obtained highlight the potential of nanofibers in the development of efficient personal protective equipments against nanoparticles.
We present a detailed study of the stellar and H I structure of the dwarf irregular galaxies Sextans A and Sextans B, members of the NGC 3109 association. We use newly obtained deep and wide-field g ...and r photometry to extend the surface brightness (SB) profiles of the two galaxies down to mu sub nu=31.0 mag/arcsecsup 2. We find that both galaxies are significantly more extended than previously traced with surface photometry, out to ~4 kpc from their centres along their major axes. Older stars are found to have more extended distribution than younger populations. We discuss these, as well as other evidence of tidal disturbance, in the framework of a past passage of the NGC 3109 association close to the Milky Way, which has been hypothesised by several authors and is also supported by the recently discovered filamentary configuration of the association itself.
A measles outbreak occurred from November 2015 to April 2016 in two northern Italian regions, affecting the Roma/Sinti ethnic population and nosocomial setting. Overall, 67 cases were reported. ...Median age of 43 cases in three Roma/Sinti camps was four years, nosocomial cases were mainly adults. The outbreak was caused by a new measles virus B3.1 variant. Immunisation resources and strategies should be directed at groups with gaps in vaccine coverage, e.g. Roma/Sinti and healthcare workers.
In 2017, Italy experienced a large measles epidemic with 5408 cases and four deaths. As Subnational Reference Laboratory of the Measles and Rubella surveillance NETwork (MoRoNET), the EpiSoMI ...(Epidemiology and Molecular Surveillance of Infections) Laboratory (University of Milan) set up rapid and active surveillance for the complete characterisation of the Measles virus (Mv) responsible for the large measles outbreak in Milan and surrounding areas (Lombardy, Northern Italy). The aims of this study were to describe the genetic profile of circulating viruses and to track the pathway of measles transmission. Molecular analysis was performed by sequencing the highly variable 450 nucleotides region of the N gene (N-450) of Mv genome. Two-hundred and ninety-nine strains of Mv were analysed. The phylogenetic analysis showed five different variants, two not previously described in the studied area, belonging to D8 and B3 genotypes. Three events of continuous transmission of autochthonous variants (D8-Osaka, D8-London and B3-Milan variants) and two events of continuous transmission of imported variants (B3-Dublin and D8-Hulu Langat) tracked five different transmission pathways. These pathways outlined two epidemic peaks: the first in April and the second in July 2017. The correlation between Mv variant and the epidemiological data may enable us to identify the sources of virus importation and recognise long-lasting virus transmission pathways.
A contact investigation following a case of infectious tuberculosis (TB) reported in a call centre in Milan (Italy) led to the identification of three additional cases that had occurred in employees ...of the same workplace during the previous 5 years, one of whom was the probable source case. Thirty-three latent infections were also identified. At the time of diagnosis, the source case, because of fear of stigma related to TB, claimed to be unemployed and a contact investigation was not performed in the workplace. Cases were linked through genotyping of Mycobacterium tuberculosis. TB stigma has been described frequently, mainly in high-incidence settings, and is known to influence health-seeking behaviours and treatment adherence. The findings in this report highlight that TB-associated stigma may also lead to incomplete contact investigations. Little is known about the causes and impact of TB-related stigma in low-incidence countries and this warrants further exploration. Research is also needed to evaluate the effectiveness of specific interviewing techniques and training interventions for staff in reducing feelings of stigma in TB patients. Finally, the outbreak emphasizes the importance of integrating routine contact investigations with genotyping.
Summary The investigation of an outbreak of hepatitis C virus in an Italian haemodialysis (HD) centre showed that three patients acquired infection with the same strain, affecting a chronically ...hepatitis C virus (HCV)-infected patient receiving HD in the same room and during the same shifts. Through our observational analysis many possible modes of transmission were identified, but none could be definitively identified as the route of HCV spread in this small cluster. This outbreak confirms that repeated opportunities for nosocomial HCV transmission may occur among HD patients due to several breaches in the standard precautions for bloodborne infections by healthcare staff.
Novel nanocomposite sorbents of superparamagnetic iron oxide nanoparticles (SPION) supported onto electrospun polyacrylonitrile nanofibers were synthesized by a simple and scalable method. The ...influence of both nanofiber size and SPION loading on As( v ) adsorption capacity was studied and optimization was conducted. A maximum uptake capacity of 32.5 mmol As( v ) per gram SPION in batch mode tests using an extremely low loading of only 2.9 mg of SPION per gram of adsorbent was achieved. This represents a remarkable improvement of 36 times compared with SPION in suspension. The optimal material was tested in continuous flow operation mode, reaching an adsorption capacity of 851.7 mg As( v ) per gram of adsorbent at pH 3.8. It is also demonstrated that the new adsorbents can retain high performance when tested under real conditions using polluted wastewater from a lixiviation dump containing a large amount of competing anions (Cl − and F − ) and interfering cations (K + , Na + , Mg 2+ , and Ca 2+ ). Furthermore, there was no release of nanoparticles observed during the operation and the spent porous material can be compressed, generating a small amount of solid waste that can be easily treated or stored.
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