2,445 research outputs found

    The Rate of Short-Duration Gamma-Ray Bursts in the Local Universe

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    Following the faint gamma-ray burst, GRB 170817A, coincident with a gravitational wave-detected binary neutron star merger at d40d\sim40 Mpc, we consider the constraints on a local population of faint short duration GRBs (defined here broadly as T90<4T_{90}<4 s). We review proposed low-redshift short-GRBs and consider statistical limits on a d200d\lessapprox200 Mpc population using Swift/Burst Alert Telescope (BAT), Fermi/Gamma-ray Burst Monitor (GBM), and Compton Gamma-Ray Observatory (CGRO) Burst and Transient Source Experiment (BATSE) GRBs. Swift/BAT short-GRBs give an upper limit for the all-sky rate of <4<4 y1^{-1} at d<200d<200 Mpc, corresponding to <5<5% of SGRBs. Cross-correlation of selected CGRO/BATSE and Fermi/GBM GRBs with d<100d<100 Mpc galaxy positions returns a weaker constraint of 12 y1\lessapprox12\ {\rm y^{-1}}. A separate search for correlations due to SGR giant flares in nearby (d<11d<11 Mpc) galaxies finds an upper limit of <3 y1<3\ {\rm y^{-1}}. Our analysis suggests that GRB 170817A-like events are likely to be rare in existing SGRB catalogues. The best candidate for an analogue remains GRB 050906, where the Swift/BAT location was consistent with the galaxy IC0327 at d132d\approx132 Mpc. If binary neutron star merger rates are at the high end of current estimates, then our results imply that at most a few percent will be accompanied by detectable gamma-ray flashes in the forthcoming LIGO/Virgo science runs.Comment: 16 pages, 4 figures, 1 table. Published in Galaxies as part of the Special Issue, "Observations and Theory of Short GRBs at the Dawn of the Gravitational Wave Era

    Malaria-filaria coinfection in mice makes malarial disease more severe unless filarial infection achieves patency

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    Coinfections are common in natural populations, and the literature suggests that helminth coinfection readily affects how the immune system manages malaria. For example, type 1–dependent control of malaria parasitemia might be impaired by the type 2 milieu of preexisting helminth infection. Alternatively, immunomodulatory effects of helminths might affect the likelihood of malarial immunopathology. Using rodent models of lymphatic filariasis (Litomosoides sigmodontis) and noncerebral malaria (clone AS Plasmodium chabaudi chabaudi), we quantified disease severity, parasitemia, and polyclonal splenic immune responses in BALB/c mice. We found that coinfected mice, particularly those that did not have microfilaremia (Mf), had more severe anemia and loss of body mass than did mice with malaria alone. Even when controlling for parasitemia, malaria was most severe in Mf coinfected mice, and this was associated with increased interferon-g responsiveness. Thus, in Mf mice, filariasis upset a delicate immunological balance in malaria infection and exacerbated malaria-induced immunopathology. Helminth infections are prevalent throughout tropical regions where malaria is transmitted [1–5]. Interactions among infections commonly alter disease severity [6, 7], and malaria-helminth coinfection can either exac

    Remote Sensing - based precision agriculture tool for the sugar industry

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    This project aimed to develop remote sensing applications that were both relevant and of commercial benefit to the Australian sugar industry and therefore adoptable. Such applications included the in season mapping of crop vigour so as to guide future management strategies, the identification of specific abiotic and biotic cropping constraints, and the conversion of GNDVI variability maps into yield at the block, farm and regional level. In order to achieve these applications the project team reviewed an array of remote sensing platforms, timing of imagery capture, software and analysis protocols; as well as distribution formats of derived imagery products, to a range of end users. The project developed strong collaborative linkages with all levels of the industry including mills, productivity services, agronomists, growers and researchers and increased its initial coverage from three individual farms in Bundaberg, Burdekin and the Herbert, coinciding with project CSE022, to include over 33,000 crops grown across 6 growing regions (Mulgrave, Herbert, Burdekin, Bundaberg, ISIS and Condong) during the 2011/2012 season

    Most of the response elicited against Wolbachia surface protein in filarial nematode infection is due to the infective larval stage

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    Immune responses to the intracellular Wolbachia bacteria of filarial nematodes are thought to contribute to the pathologic process of filarial infection. Here, we compare antibody responses of subjects living in an area where lymphatic filariasis is endemic with antibody responses elicited in a murine model of filarial infection, to provide evidence that the infective larval stage (L3), not adult nematodes, are the primary inducer of responses against Wolbachia. In human subjects, antibody responses to Brugia malayi Wolbachia surface protein (WSP) are most often correlated with antibody responses to the L3 stage of B. malayi. Analysis of anti-WSP responses induced in mice by different stages of the rodent filariae Litomosoides sigmodontis shows that the strongest anti-WSP response is elicited by the L3 stage. Although adult filarial nematode death may play a role in the generation of an anti-WSP response, it is the L3 stage that is the major source of immunogenic material, and incoming L3 provide a continual boosting of the anti-WSP response. Significant exposure to the endosymbiotic bacteria may occur earlier in nematode infection than previously thought, and the level of exposure to infective insect bites may be a key determinant of disease progression

    Inflammation as a Central Mechanism in Alzheimer\u27s Disease

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    Alzheimer\u27s disease (AD) is a progressive neurodegenerative disorder that is characterized by cognitive decline and the presence of two core pathologies, amyloid β plaques and neurofibrillary tangles. Over the last decade, the presence of a sustained immune response in the brain has emerged as a third core pathology in AD. The sustained activation of the brain\u27s resident macrophages (microglia) and other immune cells has been demonstrated to exacerbate both amyloid and tau pathology and may serve as a link in the pathogenesis of the disorder. In the following review, we provide an overview of inflammation in AD and a detailed coverage of a number of microglia-related signaling mechanisms that have been implicated in AD. Additional information on microglia signaling and a number of cytokines in AD are also reviewed. We also review the potential connection of risk factors for AD and how they may be related to inflammatory mechanisms

    Death or survival from invasive pneumococcal disease in Scotland: associations with serogroups and multilocus sequence types

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    We describe associations between death from invasive pneumococcal disease (IPD) and particular serogroups and sequence types (STs) determined by multilocus sequence typing (MLST) using data from Scotland. All IPD episodes where blood or cerebrospinal fluid (CSF) culture isolates were referred to the Scottish Haemophilus, Legionella, Meningococcal and Pneumococcal Reference Laboratory (SHLMPRL) from January 1992 to February 2007 were matched to death certification records by the General Register Office for Scotland. This represented 5959 patients. The median number of IPD cases in Scotland each year was 292. Deaths, from any cause, within 30 days of pneumococcal culture from blood or CSF were considered to have IPD as a contributing factor. Eight hundred and thirty-three patients died within 30 days of culture of Streptococcus pneumoniae from blood or CSF [13.95%; 95% confidence interval (13.10, 14.80)]. The highest death rates were in patients over the age of 75. Serotyping data exist for all years but MLST data were only available from 2001 onward. The risk ratio of dying from infection due to particular serogroups or STs compared to dying from IPD due to all other serogroups or STs was calculated. Fisher's exact test with Bonferroni adjustment for multiple testing was used. Age adjustment was accomplished using the Cochran-Mantel-Haenszel test and 95% confidence intervals were reported. Serogroups 3, 11 and 16 have increased probability of causing fatal IPD in Scotland while serogroup 1 IPD has a reduced probability of causing death. None of the 20 most common STs were significantly associated with death within 30 days of pneumococcal culture, after age adjustment. We conclude that there is a stronger association between a fatal outcome and pneumococcal capsular serogroup than there is between a fatal outcome and ST
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