95 research outputs found

    A robust method for investigating galactic evolution in the submillimetre waveband: II the submillimetre background and source counts

    Get PDF
    This is the second of two papers describing a model of galactic evolution in the submillimetre waveband. The model incorporates a self-consistent treatment of the evolution of dust and stars, is normalized to the submillimetre properties of galaxies in the local universe, and can be used to make predictions for both disk and elliptical galaxies and for `closed-box', `inflow', and `outflow' models of galactic evolution. In Paper I we investigated whether it is possible to explain the extreme dust masses of high-redshift quasars and radio galaxies by galactic evolution. In this paper we use the model to make predictions of the submillimetre background and source counts. All our disk-galaxy models exceed at short wavelengths the submillimetre background recently measured by Puget et al. (1996). We also find that it is possible to fit the background over the entire wavelength range with a elliptical model but not with a disk model. We make source count predictions at 190 μ\mum for the ISOPHOT instrument on ISO and at 850 μ\mum for SCUBA. We show that the shape of the 850 μ\mu m source counts depends almost entirely on the mass spectrum of the radiating objects. Finally, we consider the limitations of the models. We find that one of the biggest uncertainties in the model is our lack of information about the submillimetre properties of nearby galaxies, in particular the lack of a direct measurement of the submillimetre luminosity function.Comment: 17 pages, 9 postscript figures, TEX, accepted by MNRA

    Regions of star formation: chemical issues. Discussion session

    Full text link
    This is an electronic version of the lecture presented at the Astronomical Society of the Pacific Conference held in Granada, Spain, 24-28 September, 2002

    Street Crime in London: Deterrence, Disruption and Displacement

    Get PDF
    In early 2002 the Government implemented the Street Crime Initiative (SCI) in response to a rapid rise in street crime and growing public and media concern. The report examines the nature of street crime in the capital during 2001/02 and the early stages of the government initiative designed to tackle it. The study takes an innovative approach combining offence statistics, information gathered from interviews with offenders and those involved in the Street Crime Initiative (SCI) and crime mapping techniques to assess the impact of the SCI. It pays particular attention to how these offences can displace into other forms of crime or shift across time or place. It was precisely these issues which led the Government Office for London ultimately to commission this study in order to understand the nature of street crime across the London region

    Street crime in London: deterrence, disruption and displacement

    Get PDF
    In early 2002 the Government implemented the Street Crime Initiative (SCI) in response to a rapid rise in street crime and growing public and media concern. The report examines the nature of street crime in the capital during 2001/02 and the early stages of the government initiative designed to tackle it. The study takes an innovative approach combining offence statistics, information gathered from interviews with offenders and those involved in the Street Crime Initiative (SCI) and crime mapping techniques to assess the impact of the SCI. It pays particular attention to how these offences can displace into other forms of crime or shift across time or place. It was precisely these issues which led the Government Office for London ultimately to commission this study in order to understand the nature of street crime across the London region

    Recommendations for dealing with waste contaminated with Ebola virus: a Hazard Analysis of Critical Control Points approach

    Get PDF
    Objective To assess, within communities experiencing Ebola virus outbreaks, the risks associated with the disposal of human waste and to generate recommendations for mitigating such risks. Methods A team with expertise in the Hazard Analysis of Critical Control Points framework identified waste products from the care of individuals with Ebola virus disease and constructed, tested and confirmed flow diagrams showing the creation of such products. After listing potential hazards associated with each step in each flow diagram, the team conducted a hazard analysis, determined critical control points and made recommendations to mitigate the transmission risks at each control point. Findings The collection, transportation, cleaning and shared use of blood-soiled fomites and the shared use of latrines contaminated with blood or bloodied faeces appeared to be associated with particularly high levels of risk of Ebola virus transmission. More moderate levels of risk were associated with the collection and transportation of material contaminated with bodily fluids other than blood, shared use of latrines soiled with such fluids, the cleaning and shared use of fomites soiled with such fluids, and the contamination of the environment during the collection and transportation of blood-contaminated waste. Conclusion The risk of the waste-related transmission of Ebola virus could be reduced by the use of full personal protective equipment, appropriate hand hygiene and an appropriate disinfectant after careful cleaning. Use of the Hazard Analysis of Critical Control Points framework could facilitate rapid responses to outbreaks of emerging infectious disease

    Using paired serology and surveillance data to quantify dengue transmission and control during a large outbreak in Fiji.

    Get PDF
    Dengue is a major health burden, but it can be challenging to examine transmission and evaluate control measures because outbreaks depend on multiple factors, including human population structure, prior immunity and climate. We combined population-representative paired sera collected before and after the 2013/14 dengue-3 outbreak in Fiji with surveillance data to determine how such factors influence transmission and control in island settings. Our results suggested the 10-19 year-old age group had the highest risk of infection, but we did not find strong evidence that other demographic or environmental risk factors were linked to seroconversion. A mathematical model jointly fitted to surveillance and serological data suggested that herd immunity and seasonally varying transmission could not explain observed dynamics. However, the model showed evidence of an additional reduction in transmission coinciding with a vector clean-up campaign, which may have contributed to the decline in cases in the later stages of the outbreak

    Role of Environmental Factors in Shaping Spatial Distribution of Salmonella enterica Serovar Typhi, Fiji.

    Get PDF
    Fiji recently experienced a sharp increase in reported typhoid fever cases. To investigate geographic distribution and environmental risk factors associated with Salmonella enterica serovar Typhi infection, we conducted a cross-sectional cluster survey with associated serologic testing for Vi capsular antigen-specific antibodies (a marker for exposure to Salmonella Typhi in Fiji in 2013. Hotspots with high seroprevalence of Vi-specific antibodies were identified in northeastern mainland Fiji. Risk for Vi seropositivity increased with increased annual rainfall (odds ratio [OR] 1.26/quintile increase, 95% CI 1.12-1.42), and decreased with increased distance from major rivers and creeks (OR 0.89/km increase, 95% CI 0.80-0.99) and distance to modeled flood-risk areas (OR 0.80/quintile increase, 95% CI 0.69-0.92) after being adjusted for age, typhoid fever vaccination, and home toilet type. Risk for exposure to Salmonella Typhi and its spatial distribution in Fiji are driven by environmental factors. Our findings can directly affect typhoid fever control efforts in Fiji.This study was supported by the World Health Organization, Division of Pacific Technical Support (grant 2013/334890-0); the Chadwick Trust; the Bill and Melinda Gates Foundation (grant OPP1033751); and the Wellcome Trust of Great Britain (grant 100087/Z/12/Z)
    corecore