1,721,172 research outputs found
The impact of ageing on trauma-related bleeding and coagulopathy
Full text linkThe epidemiology of major injury is changing as the population ages, revealing gaps in our understanding of the management of older patients with trauma-related bleeding. Physiology and haemostasis alter with normal ageing and could attenuate the response to bleeding in an older person. The aim of this thesis was to explore the impact of the ageing trauma demographic on the presentation and management of bleeding and coagulopathy in trauma.
I conducted a systematic review to explore the evidence across age for the use of blood transfusion strategies in acute trauma haemorrhage. I identified 10 randomised controlled trials; older patients were not well represented. There were no randomised trials in older people or trials that evaluated interventions for different age groups.
A Delphi study was undertaken to develop a new consensus research definition for major bleeding in trauma. This definition was applied to the Trauma Audit Research Network registry to assess the effect of age on risk factors for major bleeding. I found older patients with bleeding were less likely to present with tachycardia than younger patients. Multivariable logistic regression using seven risk factors (age, male gender, penetrating injury, mechanism of injury, hypotension and tachycardia and unstable pelvis) showed all were independently significantly associated with bleeding. I also
identified a negative interaction between age and penetrating injury, and age and mechanism of injury. Multiple imputation was used to handle missing data and the significance of the risk factors in the imputation model was broadly similar to the complete case analysis model.
The effect of age on coagulation and fibrinolytic parameters was assessed in a multicentre cohort study. In patients who did not receive tranexamic acid, after adjusting for key covariates including presence of bleeding and injury severity, I found older age was associated with heightened fibrinolytic activity and fibrinogen levels compared with younger age.
The programme of work in this thesis has provided new data showing that age has a significant effect on the clinical presentation and risk factors for bleeding. Furthermore, coagulation and fibrinolytic parameters appear altered across age. These data are exploratory and hypothesis-generating. They inform future research areas to assess the effectiveness of different interventions including tranexamic acid across age, develop age-adapted transfusion protocols and prediction models for bleeding that take age into consideration
Effectiveness and cost-effectiveness of a fully self-guided internet-based intervention for sub-clinical social anxiety symptoms: protocol for a randomised controlled trial
No full textDesign and objective: this paper describes the protocol for a large-scale pragmatic, randomised controlled trial and economic evaluation to investigate the effectiveness and cost-effectiveness of the self-directed E-Couch social anxiety module versus a waiting list control condition, for reducing sub-clinical social anxiety symptoms in the general population. Study population: community-based adults (aged 18+) with social anxiety symptoms that do not meet the criteria for social anxiety disorder recruited via a direct-to-consumer advertisement on national websites. Intervention and control: intervention is the self-guided E-Couch social anxiety module. Control group participants are placed on a waiting list to receive the intervention at the end of the trial. Both groups receive email and text message reminders.Outcome measures: the primary outcome will be change in self-reported social anxiety score using the Social Phobia Inventory (SPIN). Secondary outcomes will be the changes in the following self-report measures: Brief Fear of Negative Evaluation scale (BFNE-S); depression (CES-D); mental wellbeing (SWEMWEBS); health status (SF36); use of health services; safety events; and adherence, retention, and attrition rates. All measures will be administered at baseline, 6 weeks, and 3, 6 and 12 months. Analysis: a mixed effects model will be used to analyse the effect of the intervention on the primary and secondary outcomes (intention to treat analysis). Secondary analyses will explore moderators and mediators of effect. A prospective economic evaluation, conducted from a NHS and social care perspective, will provide estimates of cost utility and cost-effectiveness. An interview study will be conducted with 20 participants to explore issues including acceptability, adherence, retention and attrition
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effects of cognitive behavioural therapy for insomnia on the mental health of university students: study protocol for a randomized controlled trial
Full text linkBackground: Insomnia, defined as repeated difficulties getting or staying asleep, is common in the general population. Such sleep difficulties are a problem in their own right, but increasingly it is being recognised that they may also be a contributory factor in the development of a wide range of mental health problems. Our focus is upon the relationship between insomnia and psychotic experiences, such as paranoia and hallucinations. Psychotic experiences commonly occur in mild forms in the general population and have been linked to disrupted sleep. These psychotic-like experiences raise the risk of development of a clinical disorder. Our aim is to reduce insomnia in a large general population group, and examine the effect on paranoia and hallucinations at the age when mental health problems typically emerge. The primary hypotheses are that cognitive behaviour therapy (CBT) for insomnia will reduce insomnia and also levels of paranoia and hallucinations. The theoretical links will be substantiated by a planned mediation analysis. Improvements in a number of other mental health outcomes are also predicted.Methods/Design: We will carry out a parallel group, randomised controlled trial of 2,614 students with insomnia in universities across the UK. In the Oxford Access for Students Improving Sleep (OASIS) trial, participants will be randomised to digital CBT for insomnia (in addition to treatment as usual) or treatment as usual. Online assessments will take place at zero, three, 10 (post-treatment), and 22 (follow-up) weeks. Primary outcomes are insomnia and psychotic-like experiences (paranoia or hallucinatory experiences) at 10 weeks. Secondary outcomes are levels of mania, depression, anxiety, nightmares, psychological wellbeing, and the development of mental health disorders. All main analyses will be carried out at the end of the last follow-up assessment and will be based on the intention-to-treat principle. The trial is funded by the Wellcome Trust.Discussion: This study will be the first large-scale causal test of the relationship between sleep disturbance and psychotic experiences. It will provide evidence concerning the clinical effects of treating insomnia in young adults.<br/
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Pneumococcal serotype-specific antibodies persist through early childhood after infant immunization: follow-up from a randomized controlled trial
Full text linkBACKGROUND: In a previous UK multi-center randomized study 278 children received three doses of 7-valent (PCV-7) or 13-valent (PCV-13) pneumococcal conjugate vaccine at 2, 4 and 12 months of age. At 13 months of age, most of these children had pneumococcal serotype-specific IgG concentrations ?0.35 µg/ml and opsonophagocytic assay (OPA) titers ?8.METHODS:Children who had participated in the original study were enrolled again at 3.5 years of age. Persistence of immunity following infant immunization with either PCV-7 or PCV-13 and the immune response to a PCV-13 booster at pre-school age were investigated.RESULTS: In total, 108 children were followed-up to the age of 3.5 years and received a PCV-13 booster at this age. At least 76% of children who received PCV-7 or PCV-13 in infancy retained serotype-specific IgG concentrations ?0.35 µg/ml against each of 5/7 shared serotypes. For serotypes 4 and 18C, persistence was lower at 22-42%. At least 71% of PCV-13 group participants had IgG concentrations ?0.35 µg/ml against each of 4/6 of the additional PCV-13 serotypes; for serotypes 1 and 3 this proportion was 45% and 52%. In the PCV-7 group these percentages were significantly lower for serotypes 1, 5 and 7F. A pre-school PCV-13 booster was highly immunogenic and resulted in low rates of local and systemic adverse effects.CONCLUSION: Despite some decline in antibody from 13 months of age, these data suggest that a majority of pre-school children maintain protective serotype-specific antibody concentrations following conjugate vaccination at 2, 4 and 12 months of age
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The impact of adjustment for covariates on meta-analysis of randomised intervention studies for binary outcome
Full text linkBackground Covariate adjustment analysis is often used in epidemiological studies but is less common in randomised controlled trials (RCTs) and RCT meta-analyses. There is a lack of consensus on whether the analysis of RCT data should adjust for important baseline covariates. The estimated treatment effect of a binary covariate can differ when logistic regression is carried out, even when the covariate is balanced between treatment groups. Objectives The objectives of this study were to examine the factors that affect the impact of adjusted analysis in different RCT scenarios and to explore the impact of adjusted analysis in RCT meta-analysis. Methods Simulation and sampling studies were conducted to identify the factors that affect the impact of using an adjusted logistic regression model. Two covariates, one continuous and one binary, were considered simultaneously. The event rate, treatment effect, binary and continuous variable distributions, covariate prognostic strengths, and correlation between the covariates were varied during the simulations. The impact of adjustment on RCT meta-analysis was investigated using individual participant data obtained from the Perinatal Antiplatelet Review of International Studies. Different methods of performing unadjusted and adjusted meta-analysis were compared. Results The simulation results suggest that adjustment only has a notable effect in extreme scenarios, such as a very large treatment effect or highly prognostic covariates. The relative difference between the unadjusted and adjusted odds ratios was found to be larger than 50% under these extreme scenarios. Covariate adjustment is likely to have a small effect on meta-analyses with many studies. Summary Adjusted analysis should be carried out by design. Performing adjusted analysis in a meta-analysis can be challenging as sufficient information about the covariates is often not available
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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