277 research outputs found
The Swift X-ray Telescope Cluster Survey III: Cluster Catalog from 2005-2012 Archival Data
We present the Swift X-ray Cluster Survey (SWXCS) catalog obtained using
archival data from the X-ray telescope (XRT) on board the Swift satellite
acquired from 2005 to 2012, extending the first release of the SWXCS. The
catalog provides positions, soft fluxes, and, when possible, optical
counterparts for a flux-limited sample of X-ray group and cluster candidates.
We consider the fields with Galactic latitude |b| > 20 degree to avoid high HI
column densities. We discard all of the observations targeted at groups or
clusters of galaxies, as well as particular extragalactic fields not suitable
to search for faint extended sources. We finally select ~3000 useful fields
covering a total solid angle of ~400 degree^2. We identify extended source
candidates in the soft-band (0.5-2keV) images of these fields using the
software EXSdetect, which is specifically calibrated for the XRT data.
Extensive simulations are used to evaluate contamination and completeness as a
function of the source signal, allowing us to minimize the number of spurious
detections and to robustly assess the selection function. Our catalog includes
263 candidate galaxy clusters and groups down to a flux limit of 7E-15
erg/cm^2/s in the soft band, and the logN-logS is in very good agreement with
previous deep X-ray surveys. The final list of sources is cross-correlated with
published optical, X-ray, and SZ catalogs of clusters. We find that 137 sources
have been previously identified as clusters, while 126 are new detections.
Currently, we have collected redshift information for 158 sources (60% of the
entire sample). Once the optical follow-up and the X-ray spectral analysis of
the sources are complete, the SWXCS will provide a large and well-defined
catalog of groups and clusters of galaxies to perform statistical studies of
cluster properties and tests of cosmological models.Comment: 41 pages, 16 figures, 3 tables, published on ApJS in Jan 201
Waterborne outbreak of Norwalk-like virus gastroenteritis at a tourist resort, Italy.
In July 2000, an outbreak of gastroenteritis occurred at a tourist resort in the Gulf of Taranto in southern Italy. Illness in 344 people, 69 of whom were staff members, met the case definition. Norwalk-like virus (NLV) was found in 22 of 28 stool specimens tested. The source of illness was likely contaminated drinking water, as environmental inspection identified a breakdown in the resort water system and tap water samples were contaminated with fecal bacteria. Attack rates were increased (51.4%) in staff members involved in water sports. Relative risks were significant only for exposure to beach showers and consuming drinks with ice. Although Italy has no surveillance system for nonbacterial gastroenteritis, no outbreak caused by NLV has been described previously in the country
Severe pertussis infection in infants less than 6 months of age: clinical manifestations and molecular characterization
We conducted a study to determine the main traits of pertussis among unimmunized infants less than 6 months of age. From August 2012 to March 2015, 141 nasopharyngeal aspirates (NPAs) were collected from infants with respiratory symptoms attending 2 major hospitals in Rome. Clinical data were recorded and analyzed. Lab-confirmation was performed by culture and realtime PCR. B. pertussis virulence-associated genes (ptxP, ptxA and prn), together with multilocus variable-number tandem repeat analysis (MLVA), were also investigated by the sequence-based analysis on the DNAs extracted from positive samples. Antibiotic susceptibility with Etest was defined on 18 viable B. pertussis isolates. Samples from 73 infants resulted positives for B. pertussis. The median age of the patients was 45 d (range 7–165); 21 infants were treated with macrolides before hospital admission. Cough was reported for a median of 10 d before admission and 18 d after hospital discharge among infected infants, 84% of whom showed paroxysmal cough. No resistance to macrolides was detected. Molecular analysis identified MT27 as the predominant MLVA profile, combined with ptxP3-ptxA1-prn2 associated virulence genes. Although our data may not be generalized to the whole country, they provide evidence of disease severity among infants not vaccinated against pertussis. Moreover, genetically related B. pertussis strains, comprising allelic variants of virulence associated genes, were identified
Attitude of Italian physicians toward pertussis diagnosis.
Resurgence of pertussis has been observed in several countries whereas Italy continues to be a low incidence country. We hypothesize that the low reported incidence of pertussis in Italy could be biased by the attitude of physicians to suspect and diagnose pertussis in different age groups. We investigated the attitude of Italian physicians toward pertussis diagnosis through clinical scenarios. A cross-sectional study was conducted in June 2012 sending online questionnaires to pediatricians and general practitioners (GPs) involved in ambulatory primary care. The questionnaire included five clinical scenarios of patients of different ages (45 d, 5 y, 11 y, 24 y, 58 y) with prolonged cough of at least 2 weeks. Respondents were asked to choose a diagnosis among a list of 14. We observed a decreasing trend of suspected pertussis diagnosis with increasing age of the patient (from 46% at 45 d to 0 at 58 y). In Italy pertussis is seldom suspected in the differential diagnosis of cough particularly in adults. This may cause a significant under-notification of pertussis, with a higher impact in older age groups. Educational programs should be reinforced to consider the differential diagnosis of pertussis in individuals with atypical presentation and in older age groups
Metabolic Syndrome in Italian Obese Children and Adolescents: Stronger Association with Central Fat Depot than with Insulin Sensitivity and Birth Weight
Aim. To evaluate whether body fat distribution, birth weight, and family history for diabetes (FHD) were associated with metabolic syndrome (MetS) in children and adolescents. Methods. A total of 439 Italian obese children and adolescents (5–18 years) were enrolled. Subjects were divided into 2 groups: prepubertal and pubertal. MetS was diagnosed according to the adapted National Cholesterol Education Program criteria. Birth weight percentile, central obesity index (measured by dual-energy X-ray absorptiometry), insulin sensitivity (ISI), and disposition index were evaluated. Multivariate logistic regression models were used to determine variables associated with MetS. Results. The prevalence of MetS was 17%, with higher percentage in adolescents than in children (21 versus 12%). In the overall population, central obesity index was a stronger predictor of MetS than insulin sensitivity and low birth weight. When the two groups were considered, central fat depot remained the strongest predictor of MetS, with ISI similarly influencing the probability of MetS in the two groups and birth weight being negatively associated to MetS only in pubertal individuals. Neither FHD nor degree of fatness was a significant predictor of MetS. Conclusion. Simple clinical parameters like increased abdominal adiposity and low birth weight could be useful tools to identify European obese adolescents at risk for metabolic complications
An infectious disease model on empirical networks of human contact: bridging the gap between dynamic network data and contact matrices
The integration of empirical data in computational frameworks to model the
spread of infectious diseases poses challenges that are becoming pressing with
the increasing availability of high-resolution information on human mobility
and contacts. This deluge of data has the potential to revolutionize the
computational efforts aimed at simulating scenarios and designing containment
strategies. However, the integration of detailed data sources yields models
that are less transparent and general. Hence, given a specific disease model,
it is crucial to assess which representations of the raw data strike the best
balance between simplicity and detail. We consider high-resolution data on the
face-to-face interactions of individuals in a hospital ward, obtained by using
wearable proximity sensors. We simulate the spread of a disease in this
community by using an SEIR model on top of different mathematical
representations of the contact patterns. We show that a contact matrix that
only contains average contact durations fails to reproduce the size of the
epidemic obtained with the high-resolution contact data and also to identify
the most at-risk classes. We introduce a contact matrix of probability
distributions that takes into account the heterogeneity of contact durations
between (and within) classes of individuals, and we show that this
representation yields a good approximation of the epidemic spreading properties
obtained by using the high-resolution data. Our results mark a step towards the
definition of synopses of high-resolution dynamic contact networks, providing a
compact representation of contact patterns that can correctly inform
computational models designed to discover risk groups and evaluate containment
policies. We show that this novel kind of representation can preserve in
simulation quantitative features of the epidemics that are crucial for their
study and management
Varicella Skin Complications in Childhood: A Case Series and a Systematic Review of the Literature
Prevalence of psychiatric symptoms in children and adolescents one year after the 2009 L'Aquila earthquake
Background: In 2009, an earthquake devastated the Abruzzo region in Italy. Despite the occurrence of several disasters in this country, no study on mental health of Italian children has ever been conducted in complex emergencies. Objective of the study was to assess the prevalence of psychiatric symptoms among children in the affected area 12 to 17 months after the event.Methods: A community sample of 1839 3-14 years children was identified from the general population assigned to 37 paediatricians of the National Health System, including children living in the earthquake epicentre, the surrounding earthquake zone, and the adjacent non-affected areas. Psychiatric symptoms were assessed with the Child Behavior Checklist (CBCL) and the Youth Self Report (YSR), completed by 452 children aged 11-14 years. The association between symptoms and sociodemographic, health, family, and earthquake-related factors was examined.Results: The prevalence of CBCL-defined cases was 14.9% in the epicentre, 13.0% in the remainder earthquake zone, 13.9% in the unaffected area (p =876). No differences among areas were found when comparing the YSR results. Prevalence of CBCL-defined post-traumatic stress (PTS) cases was 8.4% in the epicentre, 4.0% in the remainder earthquake zone, 2.2% in the unaffected area (p =002). PTS and anxiety were significantly more frequent in the epicentre than in other areas only in the 6-10 year-old children group (respectively p =009 and p =014). In multivariate logistic analyses, factors associated with PTS were living in the epicentre (OR = 3.6) and child or maternal history of mental health care prior to the earthquake (respectively OR = 7.1 and OR = 4.5).Conclusions: Children living in the epicentre, particularly those 6-10 years old, had the highest prevalence of CBCL-defined cases, and of PTS and anxiety symptoms one year after the earthquake. No signs of increased psychopathology were detected in younger (3-5 years) or older children (11-14 years). Family and health related factors showed stronger association with psychiatric outcomes than earthquake-related factors. The identification of populations at higher risk of developing psychiatric symptoms has implications for public health interventions in complex emergencies
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