Sedimentary evidence spanning the last 3500 years from cores taken from the centre of Gormire Lake, Cleveland, northeast England, points to two periods of deforestation and catchment erosion. The first, mainly late Iron Age/Romano-British phase, began c. 200 BC and ended c. AD 600. The second began c. AD 1200, the time of early Monastic activity, and continued into the nineteenth century. The chronology for the core rests on 137Cs, 210Pb and 14C measurements and on the history of lead accumulation in the sediments. The majority of the AMS 14C dates are shown to be too old to varying degrees, depending on the source of the organic matter in the sediments. The record of vegetation change is derived from pollen analysis. Evidence for changes in sediment composition and source and for catchment erosion comes from magnetic measurements, element analyses using XRF, and organic biogeochemical analyses. There is a high degree of coherence between all these lines of evidence. Interpretation of the magnetic record is complicated as a result of the formation of biogenic magnetite by magnetotactic bacteria, especially during periods of minimal erosion, by the presence of the authigenic magnetic sulphide greigite and by probable magnetite dissolution. Despite these modifications to the magnetic mineral assemblage in the sediments, magnetic indications of catchment erosion are clearly distinguishable, especially in the record of the antiferromagnetic minerals haematite and goethite. Partial estimates of catchment erosion rates are presented, based on the evidence from the sediments from the deepest part of the lake.
Studies of Antarctic fauna have led to tentative identification of a range of potential pathogens for both animals and humans. The rapid increase in visitors on tourist ships to the continent, now exceeding 10,000 per year, raises the concern that humans might transmit pathogens into and between wildlife colonies. The authors investigated the feasibility and efficacy of chemical disinfection of the microbial contamination on visitors' boots. During three voyages to penguin colonies in the Ross Sea, swabs were collected from the boots of visitors prior to landing, immediately on return to the ship, after a water wash, and after a chemical disinfectant wash using Virkon S. For the first two visits, abundant growth of bacteria was identified on boots at all three stages prior to disinfection. Following disinfection, the growth of bacteria was virtually eliminated. On the third visit, previously disinfected boots grew virtually no bacteria. After this landing the bacterial growth was substantially reduced by disinfection. These results indicate that consideration should be given to including disinfection in cleaning the boots of visitors to wildlife sites in the Antarctic to reduce the risk of translocation of microbial pathogens.
ObjectiveTo describe antibiotic resistance patterns in Helicobacter pylori.
DesignCulture and antibiotic sensitivity testing of antral and gastric body biopsy samples from patients having gastroscopy.
ParticipantsConsecutive consenting patients aged 18 years or more presenting for gastroscopy from 1 July 1998 to 30 June 1999.
SettingAn open‐access gastroscopy service at an urban university tertiary hospital.
Main outcome measuresNumber of H. pylori isolates showing resistance to antibiotics; correlates of such resistance with demographic and clinical information.
ResultsOf 1580 patients undergoing endoscopy, 434 agreed to participate in the study. 108 (24.9%) had positive cultures for H. pylori, and 88 of these isolates (81%) were available for further testing. Resistance to metronidazole and clarithromycin was detected in 36% and 11%, respectively. No resistance was found to tetracycline or amoxycillin. Metronidazole resistance was commoner in younger patients (P = 0.0004) and macrolide resistance was commoner in those born outside Australia or New Zealand (P = 0.03).
ConclusionsWe found substantial resistance to metronidazole, and emerging clarithromycin resistance, but complete susceptibility to amoxycillin, tetracycline, gentamicin and cefaclor. These factors may influence the effectiveness of presently recommended eradication regimens.
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