ABSTRACT
We use joint observations by the Neil Gehrels Swift X-ray Telescope (XRT) and the Fermi Large Area Telescope (LAT) of gamma-ray burst (GRB) afterglows to investigate the nature of the long-lived high-energy emission observed by Fermi LAT. Joint broadband spectral modeling of XRT and LAT data reveal that LAT non-detections of bright X-ray afterglows are consistent with a cooling break in the inferred electron synchrotron spectrum below the LAT and/or XRT energy ranges. Such a break is sufficient to suppress the high-energy emission so as to be below the LAT detection threshold. By contrast, LAT-detected bursts are best fit by a synchrotron spectrum with a cooling break that lies either between or above the XRT and LAT energy ranges. We speculate that the primary difference between GRBs with LAT afterglow detections and the non-detected population may be in the type of circumstellar environment in which these bursts occur, with late-time LAT detections preferentially selecting GRBs that occur in low wind-like circumburst density profiles. Furthermore, we find no evidence of high-energy emission in the LAT-detected population significantly in excess of the flux expected from the electron synchrotron spectrum fit to the observed X-ray emission. The lack of excess emission at high energies could be due to a shocked external medium in which the energy density in the magnetic field is stronger than or comparable to that of the relativistic electrons behind the shock, precluding the production of a dominant synchrotron self-Compton (SSC) component in the LAT energy range. Alternatively, the peak of the SSC emission could be beyond the 0.1-100 GeV energy range considered for this analysis.
ABSTRACT
Pneumococcus is considered one of the main causes of the infections acquired in the community setting and also seems to be the most frequent cause of community-acquired pneumonia in children under 5 years of age. To establish suitable preventive measures as vaccination policy, it would be important to document the incidence of IPD. The main feature of this study was that it demanded a cooperative effort between family pediatricians and those working in the hospitals to estimate the real burden of IPD in children aged 0-36. From 1 January 2003 to 31 December 2003, a prospective active surveillance of clinical cases due to S. pneumoniae was conducted by 87 specifically-trained sentinel pediatricians [all family pediatricians] randomly selected from among those working in North-East Italy. Suspected pneumococcal infections were confirmed by blood cultures at the laboratories of the hospitals involved in the study. 32 cases were suspected, 12 of those proved positive on blood culture and 6 of these 12 confirmed cases were hospitalized. 2 were cases of meningitis, 1 of pneumonia and 9 of bacteremia. The cumulative annual incidence was 58.9 cases/100,000 infants aged 0-36 months (95% CI 30.38-102.71), meaning that North-East Italy can be classified as a mesoendemic area. This study demonstrated that the incidence of IPD in infants aged (0-36 months) is often under-estimated, documenting the importance of prospective active surveillance for assisting rational choices for public health issues.
Subject(s)
Pneumococcal Infections/epidemiology , Age Factors , Child, Preschool , Community-Acquired Infections/diagnosis , Community-Acquired Infections/epidemiology , Female , Hospitalization , Humans , Incidence , Infant , Infant, Newborn , Italy/epidemiology , Longitudinal Studies , Male , Meningitis, Pneumococcal/diagnosis , Meningitis, Pneumococcal/epidemiology , Pneumococcal Infections/diagnosis , Pneumonia, Pneumococcal/diagnosis , Pneumonia, Pneumococcal/epidemiology , Prospective StudiesABSTRACT
A hospital-based case-control study on soft tissue sarcomas (STS) was conducted in 1983-84 in Torino and in Padova (Italy). Cases (36 children with rhabdomyosarcoma (RMS) and 16 non RMS-STS) were compared to 326 controls. Histories of parental smoking habits and occupations, parental and children's exposure to ionizing radiation, children's diseases and some other variables were collected through interviews to the relatives attending the child in the hospital. A non statistically significant association was observed with both maternal age above 30 at child's birth (STS: OR = 1.5, C.I. = 0.8-2.9; RMS: OR = 1.9, C.I. = 0.9-4.0) and "in utero" exposure to diagnostic radiation (STS: OR = 1.9, C.I. = 0.5-6.5, based on 4 cases). No association was found with children's previous diseases. Paternal and maternal smoking habits were similar for RMS and STS cases and controls. Some positive associations with either maternal or paternal occupational histories were identified. They are difficult to interpret in view of the large number of comparisons and small absolute figures. They included maternal employment as medical doctor and nurse, farmer, textile worker and machine tool operator. An association was also observed with paternal occupation as butcher, building worker or employment in the production of domestic appliances. One case and no controls reported a maternal aunt affected by breast cancer.
Subject(s)
Rhabdomyosarcoma/etiology , Sarcoma/etiology , Soft Tissue Neoplasms/etiology , Case-Control Studies , Humans , Maternal Age , Risk Factors , Smoking/adverse effects , Socioeconomic FactorsABSTRACT
We report a girl with Niemann-Pick disease type B in whom short stature was recorded over a long period. Association of short stature with the presence of a polyglandular involvement in this patient is discussed.
