8,478 research outputs found

    Investigating presentational change in UK annual reports: a longitudinal perspective

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    This article examines structural and format changes in annual reports of U.K. listed companies from 1965 to 2004 with a particular focus on graph use. The article compares a new sample of 2004 annual reports with preexisting samples by Lee and by Beattie and Jones. Lee's identified trends continue. There has been a sharp increase in page length, voluntary information, and narrative information, particularly among large listed companies. A detailed analysis of voluntary disclosure indicates changes in the incidence and pattern of generic sections. Graph usage is now universal. However, key financial graph use has slightly declined, replaced by graphs depicting other operating issues. Impression management through selectivity, graphical measurement distortion, and manipulation of the length of time series graphed are common. Overall, annual reports continue to exhibit many features of public relations documents rather than financially driven, statutory documents, and the analysis of graph usage suggests a need for policy guidelines to protect users

    Model correlation and damage location for large space truss structures: Secant method development and evaluation

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    On-orbit testing of a large space structure will be required to complete the certification of any mathematical model for the structure dynamic response. The process of establishing a mathematical model that matches measured structure response is referred to as model correlation. Most model correlation approaches have an identification technique to determine structural characteristics from the measurements of the structure response. This problem is approached with one particular class of identification techniques - matrix adjustment methods - which use measured data to produce an optimal update of the structure property matrix, often the stiffness matrix. New methods were developed for identification to handle problems of the size and complexity expected for large space structures. Further development and refinement of these secant-method identification algorithms were undertaken. Also, evaluation of these techniques is an approach for model correlation and damage location was initiated

    Interpolatory Weighted-H2 Model Reduction

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    This paper introduces an interpolation framework for the weighted-H2 model reduction problem. We obtain a new representation of the weighted-H2 norm of SISO systems that provides new interpolatory first order necessary conditions for an optimal reduced-order model. The H2 norm representation also provides an error expression that motivates a new weighted-H2 model reduction algorithm. Several numerical examples illustrate the effectiveness of the proposed approach

    Isolation of tributyltin-degrading bacteria citrobacter braakii and enterobacter cloacae from butyltin-polluted sediment

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    Tributyltin compound (TBT) released into the aquatic environment is generally degraded by bacteria in water and sediment. The isolation of TBT-degrading bacteria from TBT polluted sediment leads to the indication of specific potential TBT degraders. Two new strains of bacteria designated as B2 and B3 were successfully isolated using glycerol medium containing tributyltin chloride (TBTC) at 130 μM from contaminated sediment collected from Bowling Basin in Glasgow. The observed degradation after 14 days of the microcosm from the sediment and the isolated bacteria were investigated at an initial concentration of 1 μM TBTC. It was found that TBT was degraded by the bacterial strains B2 and B3 at 8.3 and 16.9 %, respectively. The results indicate that B2 and B3 are effective as TBT degraders. EC50 of B2 and B3 in water were 88.73 and 112.53 μM TBTC, which were significantly higher than the concentration of TBT measured at the basin, suggesting a low effect of TBT on the growth and activity of bacteria. After identification using API 20E and 16S sequencing, the bacterial isolate strain B2 is Citrobacter braakii and B3 is Enterobacter cloacae. Therefore, this study has discovered two species of high resistance TBT degrader which have never been previously studied or isolated based upon TBT degradation ability

    How are normal sleeping controls selected? A systematic review of cross-sectional insomnia studies, and a standardised method to select healthy controls for sleep research

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    There appears to be some inconsistency in how normal sleepers (controls) are selected and screened for participation in research studies for comparison with insomnia patients. The purpose of the current study is to assess and compare methods of identifying normal sleepers in insomnia studies, with reference to published standards. We systematically reviewed the literature on insomnia patients which included control subjects. The resulting 37 articles were systematically reviewed with reference to the five criteria for normal sleep specified by Edinger et al. (2004). In summary, these criteria are: evidence of sleep disruption; sleep scheduling; general health; substance/medication use; and other sleep disorders. We found sleep diaries, PSG, and clinical screening examinations to be widely used with both control subjects and insomnia participants. However, there are differences between research groups in the precise definitions applied to the components of normal sleep. We found that none of reviewed studies applied all of the Edinger et al. criteria, and 16% met four criteria. In general, screening is applied most rigorously at the level of a clinical disorder, whether physical, psychiatric, or sleep. While the Edinger et al. criteria seem to be applied in some form by most researchers, there is scope to improve standards and definitions in this area. Ideally, different methods such as sleep diaries and questionnaires would be used concurrently with objective measures to ensure normal sleepers are identified, and descriptive information for control subjects would be reported. Here, we have devised working criteria and methods to be used for assessment of normal sleepers. This would help clarify the nature of the control group, in contrast to insomnia subjects and other patient groups

    Social interactions, emotion and sleep: a systematic review and research agenda

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    Sleep and emotion are closely linked, however the effects of sleep on socio-emotional task performance have only recently been investigated. Sleep loss and insomnia have been found to affect emotional reactivity and social functioning, although results, taken together, are somewhat contradictory. Here we review this advancing literature, aiming to 1) systematically review the relevant literature on sleep and socio-emotional functioning, with reference to the extant literature on emotion and social interactions, 2) summarize results and outline ways in which emotion, social interactions, and sleep may interact, and 3) suggest key limitations and future directions for this field. From the reviewed literature, sleep deprivation is associated with diminished emotional expressivity and impaired emotion recognition, and this has particular relevance for social interactions. Sleep deprivation also increases emotional reactivity; results which are most apparent with neuro-imaging studies investigating amygdala activity and its prefrontal regulation. Evidence of emotional dysregulation in insomnia and poor sleep has also been reported. In general, limitations of this literature include how performance measures are linked to self-reports, and how results are linked to socio-emotional functioning. We conclude by suggesting some possible future directions for this field
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