62 research outputs found
Population structure of pink salmon (Oncorhynchus gorbuscha) in British Columbia and Washington, determined with microsatellites
Population structure of pink salmon (Oncorhynchus gorbuscha)
from British Columbia and Washington was examined with a survey of microsatellite variation to describe the distribution of genetic variation. Variation at 16 microsatellite loci was surveyed for approximately 46,500
pink salmon sampled from 146 locations in the odd-year broodline and from 116 locations in the even-year broodline. An index of genetic differentiation, FST, over all populations and loci in the odd-year broodline was
0.005, with individual locus values ranging from 0.002 to 0.025. Population differentiation was less in the even-year broodline, with a FST value of 0.002 over all loci, and with individual locus values ranging from 0.001 to 0.005. Greater genetic diversity was observed in the odd-year broodline. Differentiation in pink salmon allele frequencies between broodlines was approximately 5.5 times greater than regional differentiation within broodlines. A regional structuring of populations was the general pattern
observed, and a greater regional structure in the odd-year broodline than in the even-year broodline. The geographic distribution of microsatellite variation in populations of pink salmon likely ref lects a distribution of broodlines from separate refuges after the last glaciation period
Age determination of Rocky Mountain Ridged Mussels (Gonidea angulata) in the Okanagan Basin, Canada
Freshwater ecosystems and the biodiversity they support are facing unprecedented threats, exemplified by broad declines of freshwater mussels within a global biodiversity hotspot. The Rocky Mountain Ridged Mussel (Gonidea angulata) is an at-risk species in Canada, with limited information on population age structure. Maximum age of the species was found to be 50 years, by counting winter annuli and validated by isotopic oxygen analysis. Employing a Bayesian Generalized Linear Mixed Model (GLMM), results showed mussels from river habitat were predicted to have faster growth rates than mussels from lake habitats, highlighting the impact of local environmental conditions, including temperature variations, primary productivity, and water quality, on mussel growth dynamics. Of concern was the limited evidence of juvenile recruitment, with the majority of specimens potentially representing an ageing population. This pattern potentially signals an early warning of impending population decline. Our results underscore the necessity of monitoring age structure as a vital component of assessing population health of freshwater mussels and the importance of understanding local environmental conditions when determining age
Late Ebola virus relapse causing meningoencephalitis: a case report
Background:
There are thousands of survivors of the 2014 Ebola outbreak in west Africa. Ebola virus can persist in survivors for months in immune-privileged sites; however, viral relapse causing life-threatening and potentially transmissible disease has not been described. We report a case of late relapse in a patient who had been treated for severe Ebola virus disease with high viral load (peak cycle threshold value 13·2).
Methods:
A 39-year-old female nurse from Scotland, who had assisted the humanitarian effort in Sierra Leone, had received intensive supportive treatment and experimental antiviral therapies, and had been discharged with undetectable Ebola virus RNA in peripheral blood. The patient was readmitted to hospital 9 months after discharge with symptoms of acute meningitis, and was found to have Ebola virus in cerebrospinal fluid (CSF). She was treated with supportive therapy and experimental antiviral drug GS-5734 (Gilead Sciences, San Francisco, Foster City, CA, USA). We monitored Ebola virus RNA in CSF and plasma, and sequenced the viral genome using an unbiased metagenomic approach.
Findings:
On admission, reverse transcriptase PCR identified Ebola virus RNA at a higher level in CSF (cycle threshold value 23·7) than plasma (31·3); infectious virus was only recovered from CSF. The patient developed progressive meningoencephalitis with cranial neuropathies and radiculopathy. Clinical recovery was associated with addition of high-dose corticosteroids during GS-5734 treatment. CSF Ebola virus RNA slowly declined and was undetectable following 14 days of treatment with GS-5734. Sequencing of plasma and CSF viral genome revealed only two non-coding changes compared with the original infecting virus.
Interpretation:
Our report shows that previously unanticipated, late, severe relapses of Ebola virus can occur, in this case in the CNS. This finding fundamentally redefines what is known about the natural history of Ebola virus infection. Vigilance should be maintained in the thousands of Ebola survivors for cases of relapsed infection. The potential for these cases to initiate new transmission chains is a serious public health concern
Decay spectroscopy of Cd-129
Excited states of In populated following the -decay of
Cd were experimentally studied with the GRIFFIN spectrometer at the
ISAC facility of TRIUMF, Canada. A 480-MeV proton beam was impinged on a
uranium carbide target and Cd was extracted using the Ion Guide Laser
Ion Source (IG-LIS). - and -rays following the decay of
Cd were detected with the GRIFFIN spectrometer comprising the plastic
scintillator SCEPTAR and 16 high-purity germanium (HPGe) clover-type detectors.
%, along with the -particles were detected with SCEPTAR. From the
-- coincidence analysis, 32 new transitions and 7 new
excited states were established, expanding the previously known level scheme of
In. The values deduced from the -feeding intensities
suggest that some of the high-lying states were populated by the allowed Gamow-Teller (GT) transition, which
indicates that the allowed GT transition is more dominant in the Cd
decay than previously reported. Observation of fragmented Gamow-Teller
strengths is consistent with theoretical calculations.Comment: 13 pages, 9 figures, to be published in Physical Review
Variable alterations of the microbiota, without metabolic or immunological change, following faecal microbiota transplantation in patients with chronic pouchitis
© 2015 The Authors. Published by Springer Nature. This is an open access article available under a Creative Commons licence.
The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1038/srep12955Faecal microbiota transplantation (FMT) is effective in the treatment of Clostridium difficile infection, where efficacy correlates with changes in microbiota diversity and composition. The effects of FMT on recipient microbiota in inflammatory bowel diseases (IBD) remain unclear. We assessed the effects of FMT on microbiota composition and function, mucosal immune response, and clinical outcome in patients with chronic pouchitis. Eight patients with chronic pouchitis (current PDAI ‰7) were treated with FMT via nasogastric administration. Clinical activity was assessed before and four weeks following FMT. Faecal coliform antibiotic sensitivities were analysed, and changes in pouch faecal and mucosal microbiota assessed by 16S rRNA gene pyrosequencing and 1 H NMR spectroscopy. Lamina propria dendritic cell phenotype and cytokine profiles were assessed by flow cytometric analysis and multiplex assay. Following FMT, there were variable shifts in faecal and mucosal microbiota composition and, in some patients, changes in proportional abundance of species suggestive of a 'healthier' pouch microbiota. However, there were no significant FMT-induced metabolic or immunological changes, or beneficial clinical response. Given the lack of clinical response following FMT via a single nasogastric administration our results suggest that FMT/bacteriotherapy for pouchitis patients requires further optimisation.Published versio
Shell evolution approaching the N=20 island of inversion : Structure of Mg 29
The island of inversion for neutron-rich nuclei in the vicinity of N=20 has become the testing ground par excellence for our understanding and modeling of shell evolution with isospin. In this context, the structure of the transitional nucleus Mg29 is critical. The first quantitative measurements of the single-particle structure of Mg29 are reported, using data from the d(Mg28, p γ)Mg29 reaction. Two key states carrying significant 3 (f-wave) strength were identified at 2.40±0.10 (Jπ=5/2-) and 4.28±0.04 MeV (7/2-). New state-of-the-art shell-model calculations have been performed and the predictions are compared in detail with the experimental results. While the two lowest 7/2- levels are well described, the sharing of single-particle strength disagrees with experiment for both the 3/2- and 5/2- levels and there appear to be general problems with configurations involving the p3/2 neutron orbital and core-excited components. These conclusions are supported by an analysis of the neutron occupancies in the shell-model calculations
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