28 research outputs found

    Palaeoenvironmental control on distribution of crinoids in the Bathonian (Middle Jurassic) of England and France

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    Bulk sampling of a number of different marine and marginal marine lithofacies in the British Bathonian has allowed us to assess the palaeoenvironmental distribution of crinoids for the first time. Although remains are largely fragmentary, many species have been identified by comparison with articulated specimens from elsewhere, whilst the large and unbiased sample sizes allowed assessment of relative proportions of different taxa. Results indicate that distribution of crinoids well corresponds to particular facies. Ossicles of Chariocrinus and Balanocrinus dominate in deeper-water and lower-energy facies,with the former extending further into shallower-water facies than the latter. Isocrinus dominates in shallower water carbonate facies, accompanied by rarer comatulids, and was also present in the more marine parts of lagoons. Pentacrinites remains are abundant in very high-energy oolite shoal lithofacies. The presence of millericrinids within one, partly allochthonous lithofacies suggests the presence of an otherwise unknown hard substrate from which they have been transported. These results are compared to crinoid assemblages from other Mesozoic localities, and it is evident that the same morphological ad-aptations are present within crinoids from similar lithofacies throughout the Jurassic and Early Cretaceous

    Non-invasive moisture monitoring within an earth embankment : a precursor to failure

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    An experimental monitoring system is described using electrical resistivity as a proxy for imaging changing moisture content distribution in engineered earthworks. The approach is illustrated using a case history concerning a road embankment constructed of tropical red soil in western Kenya. Tropical red soils have highly variable properties, governed by their soil fabric and mineralogy. As earthworks materials, their geotechnical behaviour is extremely sensitive to changes in moisture content and compaction. The relationship between moisture content and electrical resistivity was established in the laboratory on core obtained using a monitored drilling and sampling technique. The non-invasive nature of electrical resistivity surveys was exploited in the design of a monitoring system placed below the pavement in the topmost layers of compacted soil. Monitoring over a period of 18 months is reported, starting prior to the construction of the pavement following the completion of soil compaction. Initially substantial variability in moisture content was inferred from surface monitoring, and even larger changes were seen in corresponding downhole measurements. The moisture content within the body of the embankment stabilised after 6 months, while a moist layer ‘trapped’ beneath the pavement dissipated over the following 10 months. Two surveys were undertaken during the ‘December rains’; they showed large changes in moisture content had occurred quickly in the surface layers on one side of the embankment. This area subsequently failed as a small landslip and was remediated by additional drainage

    Randomized controlled trial of olanzapine or chlorpromazine as addition to lithium in the treatment of a first manic episode with psychotic features: an 8-week, flexible dose, single-blind trial

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    Background: Association of mood stabiliser and antipsychotic medication is indicated in psychotic mania, but specific guidelines for the treatment of a first episode of psychotic mania are needed. Aims: To compare safety and efficacy profiles of chlorpromazine and olanzapine augmentation of lithium treatment in a first episode of psychotic mania. Methods: A total of 83 patients were randomised to either lithium + chlorpromazine or lithium + olanzapine in an 8-week trial. Data was collected on side effects, vital signs and weight modifications, as well as on clinical variables. Results: There were no differences in the safety profiles of both medications, but patients in the olanzapine group were significantly more likely to have reached mania remission criteria after 8 weeks. Mixed effects models repeated measures analysis of variance showed that patients in the olanzapine group reached mania remission significantly earlier than those in the chlorpromazine group. Conclusions: These results suggest that while olanzapine and chlorpromazine have a similar safety profile in a cohort of patients with first episode of psychotic mania, the former has a greater efficacy on manic symptoms. On this basis, it may be a better choice for such conditions

    A single-blind, randomised controlled trial on the effects of lithium and quetiapine monotherapy on the trajectory of cognitive functioning in first episode mania: A 12-month follow-up study.

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    BACKGROUND: Cognitive deficits have been reported during the early stages of bipolar disorder; however, the role of medication on such deficits remains unclear. The aim of this study was to compare the effects of lithium and quetiapine monotherapy on cognitive performance in people following first episode mania. METHODS: The design was a single-blind, randomised controlled trial on a cohort of 61 participants following first episode mania. Participants received either lithium or quetiapine monotherapy as maintenance treatment over a 12-month follow-up period. The groups were compared on performance outcomes using an extensive cognitive assessment battery conducted at baseline, month 3 and month 12 follow-up time-points. RESULTS: There was a significant interaction between group and time in phonemic fluency at the 3-month and 12-month endpoints, reflecting greater improvements in performance in lithium-treated participants relative to quetiapine-treated participants. After controlling for multiple comparisons, there were no other significant interactions between group and time for other measures of cognition. CONCLUSION: Although the effects of lithium and quetiapine treatment were similar for most cognitive domains, the findings imply that early initiation of lithium treatment may benefit the trajectory of cognition, specifically verbal fluency in young people with bipolar disorder. Given that cognition is a major symptomatic domain of bipolar disorder and has substantive effects on general functioning, the ability to influence the trajectory of cognitive change is of considerable clinical importance
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