1,007 research outputs found
AGN triggering in the infall regions of distant X-ray luminous galaxy clusters at 0.9 < z <~ 1.6
Observational constraints on the average radial distribution profile of AGN
in distant galaxy clusters can provide important clues on the triggering
mechanisms of AGN activity in dense environments and are essential for a
completeness evaluation of cluster selection techniques in the X-ray and
mm-wavebands. The aim of this work is a statistical study with XMM-Newton of
the presence and distribution of X-ray AGN in the large-scale structure
environments of 22 X-ray luminous galaxy clusters in the redshift range 0.9 < z
\lesssim 1.6 compiled by the XMM-Newton Distant Cluster Project (XDCP). To this
end, the X-ray point source lists from detections in the soft-band (0.35-2.4
keV) and full-band (0.3-7.5 keV) were stacked in cluster-centric coordinates
and compared to average background number counts extracted from three
independent control fields in the same observations. A significant full-band
(soft-band) excess of \sim78 (67) X-ray point sources is found in the cluster
fields within an angular distance of 8' (4Mpc) at a statistical confidence
level of 4.0 sigma (4.2 sigma), corresponding to an average number of detected
excess AGN per cluster environment of 3.5\pm0.9 (3.0\pm0.7). The data point
towards a rising radial profile in the cluster region (r<1Mpc) of predominantly
low-luminosity AGN with an average detected excess of about one point source
per system, with a tentative preferred occurrence along the main cluster
elongation axis. A second statistically significant overdensity of brighter
soft-band detected AGN is found at cluster-centric distances of 4'-6' (2-3Mpc),
corresponding to about three times the average cluster radius R200 of the
systems. If confirmed, these results would support the idea of two different
physical triggering mechanisms of X-ray AGN activity in dependence of the
radially changing large-scale structure environment of the distant clusters.Comment: 18 pages, 7 color figures, accepted for publication in Advances in
Astronomy for the special issue 'Seeking for the Leading Actor on the Cosmic
Stage: Galaxies versus Supermassive Black Holes
Presence of class I integrons in multidrug-resistant, low-prevalence Salmonella serotypes, Italy.
In 1997 to 1999, we detected class I integrons in multidrug-resistant isolates of Salmonella enterica serovars Anatum, Blockley, Brandenburg, Bredeney, Derby, Heidelberg, Livingstone, Newport, Ohio, Panama, Paratyphi B, Saintpaul, Sandiego, and Stanley
Mechanical Response of He- Implanted Amorphous SiOC/ Crystalline Fe Nanolaminates
This study investigates the microstructural evolution and mechanical response of sputter-deposited amorphous silicon oxycarbide (SiOC)/crystalline Fe nanolaminates, a single layer SiOC film, and a single layer Fe film subjected to ion implantation at room temperature to obtain a maximum He concentration of 5 at. %. X-ray diffraction and transmission electron microscopy indicated no evidence of implantation-induced phase transformation or layer breakdown in the nanolaminates. Implantation resulted in the formation of He bubbles and an increase in the average size of the Fe grains in the individual Fe layers of the nanolaminates and the single layer Fe film, but the bubble density and grain size were found to be smaller in the former. By reducing the thicknesses of individual layers in the nanolaminates, bubble density and grain size were further decreased. No He bubbles were observed in the SiOC layers of the nanolaminates and the single layer SiOC film. Nanoindentation and scanning probe microscopy revealed an increase in the hardness of both single layer SiOC and Fe films after implantation. For the nanolaminates, changes in hardness were found to depend on the thicknesses of the individual layers, where reducing the layer thickness to 14 nm resulted in mitigation of implantation-induced hardening
Shigella sonnei biotype g carrying class 2 integrons in southern Italy: a retrospective typing study by pulsed field gel electrophoresis.
Background: Emergence and global dissemination of multiresistant strains of enteric pathogens is a very concerning
problem from both epidemiological and Public Health points of view. Shigella sonnei is the serogroup of Shigella most
frequently responsible for sporadic and epidemic enteritis in developed countries. The dissemination is associated most
often to human to human transmission, but foodborne episodes have also been described. In recent years the circulation
of multiresistant strains of S. sonnei biotype g carrying a class 2 integron has been reported in many countries worldwide.
In southern Italy a strain with similar properties has been responsible for a large community outbreak occurred in 2003
in Palermo, Sicily.
The objective of this study was to date the emergence of the biotype g strain carrying the class 2 integron in southern
Italy and to evaluate the genetic heterogeneity of biotype g S. sonnei isolated throughout an extended interval of time.
Methods: A total of 31 clinical isolates of S. sonnei biotype g identified in southern Italy during the years 1971\u20132000 were
studied. The strains were identified at the serogroup level, characterized by biochemical tests and submitted to
antimicrobial susceptibility testing. Molecular typing was performed by pulsed field gel electrophoresis (PFGE) after
digestion of DNA by XbaI. Carriage of class 2 integrons was investigated by polymerase chain reaction (PCR) with specific
primers and confirmed by restriction endonuclease analysis of amplicons.
Results: The 15 isolates of S. sonnei biotype g identified in the decade 1971\u20131980 showed highly heterogeneous drug
resistance profiles and pulsotypes. None of the isolates was simultaneous resistant to streptomycin and trimethoprim
and none was class 2 integron positive. On the contrary, this resistance phenotype and class 2 integron carriage were
very common among the 16 strains of biotype g identified in the following two decades. Moreover, all the more recent
isolates, but one, showed closely related pulsotypes.
Conclusion: Although our findings refer to a limited geographic area, they provide a snapshot of integron acquisition
by an enteric pathogen responsible for several outbreaks in the years 2001\u20132003 in Italy. Molecular typing, indeed,
suggests that the emergence of biotype g class 2 integron carrying S. sonnei in southern Italy should be backdated to at
least the late 1980s. In the following decades, the circulation of biotype g appears to be sustained by multiresistant highly
related strains. Similar trend are described in several countries, but the questions about mechanism of emergence and
worldwide spread of this pathogen remain ope
Identifying Video Game Preferences Among Adults Interested in Quitting Smoking Cigarettes: Survey Study.
BACKGROUND: Smoking is the most prevalent cause of morbidity and mortality in the United States. Although most individuals who smoke express a desire to quit smoking, only a small percentage are successful. Serious games have become popular in health sectors as a potential avenue for delivering a scalable treatment that is both accessible and engaging for the smoking population. Several smoking cessation games have already been developed, but these games feature a broad range of gameplay elements and are not necessarily based on existing video game preferences in the general or smoking population.
OBJECTIVE: To better inform treatment development, this study aims to evaluate video game genre preferences among treatment-seeking individuals who smoke (N=473).
METHODS: Participants responded to a screening survey to enroll in a larger, serious game intervention for smoking cessation. During this screening survey, participants were asked to disclose their favorite video games, which resulted in 277 unique game titles. These titles were coded for genre categories based on publisher listings and game features. The genres were then analyzed for the frequency of reporting overall and across age groups.
RESULTS: Action, Role-Playing, and Action-Adventure were the most reported genres among adults aged ≤34 years; Action, Action-Adventure, and Logic were the most reported genres among adults aged 35-44 years; and Logic and Action were the most reported genres among adults aged ≥45 years.
CONCLUSIONS: These data indicate that treatment-seeking individuals who smoke have different game preferences across age groups, and the data provide novel information to inform the development of future serious games targeting the smoking population that are tailored to the preferences of their age group.
TRIAL REGISTRATION: ClinicalTrials.gov NCT03929003; https://clinicaltrials.gov/ct2/show/NCT03929003
Self-Organized Ordering of Nanostructures Produced by Ion-Beam Sputtering
We study the self-organized ordering of nanostructures produced by ion-beam
sputtering (IBS) of targets amorphizing under irradiation. By introducing a
model akin to models of pattern formation in aeolian sand dunes, we extend
consistently the current continuum theory of erosion by IBS. We obtain new
non-linear effects responsible for the in-plane ordering of the structures,
whose strength correlates with the degree of ordering found in experiments. Our
results highlight the importance of redeposition and surface viscous flow to
this nanopattern formation process.Comment: 4 pages, 2 figure
Coupling of morphology to surface transport in ion-beam irradiated surfaces. I. Oblique incidence
We propose and study a continuum model for the dynamics of amorphizable
surfaces undergoing ion-beam sputtering (IBS) at intermediate energies and
oblique incidence. After considering the current limitations of more standard
descriptions in which a single evolution equation is posed for the surface
height, we overcome (some of) them by explicitly formulating the dynamics of
the species that transport along the surface, and by coupling it to that of the
surface height proper. In this we follow recent proposals inspired by
``hydrodynamic'' descriptions of pattern formation in aeolian sand dunes and
ion-sputtered systems. From this enlarged model, and by exploiting the
time-scale separation among various dynamical processes in the system, we
derive a single height equation in which coefficients can be related to
experimental parameters. This equation generalizes those obtained by previous
continuum models and is able to account for many experimental features of
pattern formation by IBS at oblique incidence, such as the evolution of the
irradiation-induced amorphous layer, transverse ripple motion with non-uniform
velocity, ripple coarsening, onset of kinetic roughening and other.
Additionally, the dynamics of the full two-field model is compared with that of
the effective interface equation.Comment: 23 pages, 14 figures. Movies of figures 6, 7, and 8 available at
http://gisc.uc3m.es/~javier/Movies
Enhanced surveillance of invasive listeriosis in the Lombardy region, Italy, in the years 2006-2010 reveals major clones and an increase in serotype 1/2a.
Background
Invasive listeriosis is a rare, life-threatening foodborne disease. Lombardy, an Italian region accounting for 16% of the total population, reported 55% of all listeriosis cases in the years 2006-2010. The aim of our study was to provide a snapshot of listeriosis epidemiology in this region after the implementation of a voluntary laboratory-based surveillance system.
Methods
We characterized by serotyping, pulsed-field gel electrophoresis, multilocus sequence typing and detection of epidemic clone markers, 134 isolates from 132 listeriosis cases, including 15 pregnancy-related cases, occurring in the years 2006-2010 in Lombardy. Demographic and clinical characteristics of cases have also been described.
Results
The mean age of non pregnancy-associated cases was 64.7\u2009years, with 55.9% of cases being older than 65\u2009years. Cases having no underlying medical conditions accounted for 11.6%. The all-cause fatality rate of 83 cases with a known survival outcome was 25.3%.
Serotypes 1/2a and 4b comprised 52.2% and 38.8% of isolates, respectively. Seventy-three AscI pulsotypes and 25 sequence types assigned to 23 clonal complexes were recognized. Moreover, 53 (39.5%) isolates tested positive for the epidemic clone markers. Twelve molecular subtype clusters including at least three isolates were detected, with cluster 11 (1/2a/ST38) including 31 isolates identified during the entire study period. No outbreaks were notified to public health authorities during this period.
Conclusions
The findings of our study proved that epidemiology of listeriosis in Lombardy is characterized by a high prevalence of major clones and the increasing role of serotype 1/2a. Molecular subtyping is an essential tool in the epidemiology and surveillance of listeriosis. Rapid molecular cluster detection could alert about putative outbreaks, thus increasing the chance of detecting and inactivating routes of transmission
Exploitation of multi-objective optimization in retrofit analysis: a case study for the iron and steel production
Abstract Over the past few decades the issues related to the energy consumption and the climate change have been increased and they have achieved a significant position on the sustainability agenda of the steel industry. Steel production is among the largest energy-intensive industrial processes in the world, as well as one of the most important CO 2 emission sources. However, the major role of steel utilisation in the modern society is undeniable. The challenges of industrial energy systems aim at achieving CO 2 minimization, without neglecting energy efficiency as well as the development of effective models and strategies for process optimization. The application of Process Integration (PI) methods to the integrated steelmaking route, aims at achieving a reduction in the CO 2 emission by optimizing material and energy systems. The work presented in this paper is devoted to the development of a model for optimal exploitation of energy resources and by-products in integrated steelworks through application of multi-objective optimisation techniques. Cases of exploitation of the system within the management of the process gases are presented in a retrofit scenario and compared to the case of nominal operation
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