78 research outputs found

    Lamb Wave Propagation in Thermally Damaged Composites

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    The use of composites in primary and secondary structures of aerospace vehicles is important for increased performance with little weight penalty. Determining the response to thermal damage is necessary for a complete understanding of the total use environment of these materials. The objective of the research presented here is to provide a method of quantifying the amount of thermal damage in composite materials. Components which have non-visible damage, but have degraded performance on the order of several percent, are of interest. At this level of damage the safety margin designed into the structure may be compromised

    Tight coupling of leaf area index to canopy nitrogen and phosphorus across heterogeneous tallgrass prairie communities

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    Nitrogen (N) and phosphorus (P) are limiting nutrients for many plant communities worldwide. Foliar N and P along with leaf area are among the most important controls on photosynthesis and hence productivity. However, foliar N and P are typically assessed as species level traits, whereas productivity is often measured at the community scale. Here, we compared the community-level traits of leaf area index (LAI) to total foliar nitrogen (TFN) and total foliar phosphorus (TFP) across nearly three orders of magnitude LAI in grazed and ungrazed tallgrass prairie in north-eastern Kansas, USA. LAI was strongly correlated with both TFN and TFP across communities, and also within plant functional types (grass, forb, woody, and sedge) and grazing treatments (bison or cattle, and ungrazed). Across almost the entire range of LAI values and contrasting communities, TFN:TFP ratios indicated co-limitation by N and P in almost all communities; this may further indicate a community scale trend of an optimal N and P allocation per unit leaf area for growth. Previously, results from the arctic showed similar tight relationships between LAI:TFN, suggesting N is supplied to canopies to maximize photosynthesis per unit leaf area. This tight coupling between LAI, N, and P in tallgrass prairie suggests a process of optimal allocation of N and P, wherein LAI remains similarly constrained by N and P despite differences in species composition, grazing, and canopy density

    How do patient reported outcome measures (PROMs) support clinician-patient communication and patient care? A realist synthesis

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    Background: In this paper, we report the findings of a realist synthesis that aimed to understand how and in what circumstances patient reported outcome measures (PROMs) support patient-clinician communication and subsequent care processes and outcomes in clinical care. We tested two overarching programme theories: (1) PROMs completion prompts a process of self-reflection and supports patients to raise issues with clinicians and (2) PROMs scores raise clinicians’ awareness of patients’ problems and prompts discussion and action. We examined how the structure of the PROM and care context shaped the ways in which PROMs support clinician-patient communication and subsequent care processes. Results: PROMs completion prompts patients to reflect on their health and gives them permission to raise issues with clinicians. However, clinicians found standardised PROMs completion during patient assessments sometimes constrained rather than supported communication. In response, clinicians adapted their use of PROMs to render them compatible with the ongoing management of patient relationships. Individualised PROMs supported dialogue by enabling the patient to tell their story. In oncology, PROMs completion outside of the consultation enabled clinicians to identify problematic symptoms when the PROM acted as a substitute rather than addition to the clinical encounter and when the PROM focused on symptoms and side effects, rather than health related quality of life (HRQoL). Patients did not always feel it was appropriate to discuss emotional, functional or HRQoL issues with doctors and doctors did not perceive this was within their remit. Conclusions: This paper makes two important contributions to the literature. First, our findings show that PROMs completion is not a neutral act of information retrieval but can change how patients think about their condition. Second, our findings reveal that the ways in which clinicians use PROMs is shaped by their relationships with patients and professional roles and boundaries. Future research should examine how PROMs completion and feedback shapes and is influenced by the process of building relationships with patients, rather than just their impact on information exchange and decision making

    What’s wrong with evolutionary biology?

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    There have been periodic claims that evolutionary biology needs urgent reform, and this article tries to account for the volume and persistence of this discontent. It is argued that a few inescapable properties of the field make it prone to criticisms of predictable kinds, whether or not the criticisms have any merit. For example, the variety of living things and the complexity of evolution make it easy to generate data that seem revolutionary (e.g. exceptions to well-established generalizations, or neglected factors in evolution), and lead to disappointment with existing explanatory frameworks (with their high levels of abstraction, and limited predictive power). It is then argued that special discontent stems from misunderstandings and dislike of one well-known but atypical research programme: the study of adaptive function, in the tradition of behavioural ecology. To achieve its goals, this research needs distinct tools, often including imaginary agency, and a partial description of the evolutionary process. This invites mistaken charges of narrowness and oversimplification (which come, not least, from researchers in other subfields), and these chime with anxieties about human agency and overall purpose. The article ends by discussing several ways in which calls to reform evolutionary biology actively hinder progress in the field

    Metagenomic sequencing as a pathogen-agnostic clinical diagnostic tool for infectious diseases: a systematic review and meta-analysis of diagnostic test accuracy studies

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    Background: Metagenomic sequencing is frequently claimed to have the potential to revolutionise microbiology through rapid species identification and antimicrobial resistance (AMR) prediction. We assess progress towards this. Methods: We perform a systematic review and meta-analysis of all published literature on culture-independent metagenomic sequencing for pathogen-agnostic infectious disease diagnostics to August 12, 2020. Methodologic bias and applicability were assessed using QUADAS-2. (PROSPERO CRD42020163777) Results: A total of 2023 clinical samples from 13/21 eligible diagnostic test accuracy studies were included in the meta-analysis. Reference standards were culture, molecular testing, clinical decision or a composite measure. Sensitivity and specificity in the most widely investigated sample types were 90%(78-96%) and 86%(45-98%) for blood, 75%(95%CI, 54-89%) and 96%(72-100%) for CSF, and 84%(79-88%) and 67%(38-87%) for orthopaedic samples respectively. We identified limited use of controls, especially negative controls which were used in only 62%(13/21) studies. AMR prediction and comparison to phenotypic results was undertaken in four studies: categorical agreement was 88%(80%-97%), very major and major error rates were 24%(8-40%) and 5%(0-12%) respectively. Better human DNA depletion methods are required: a median 91%(IQR 82-98%)[range 76-98%] of sequences were classified as human. The median(IQR)[range] time from sample to result was 29(24-94)[4-144] hours. The reported consumables cost per sample ranged from 130−130-685. Conclusions: There is scope for improving the quality of reporting in clinical metagenomic studies. Although our results are limited by the heterogeneity displayed, our results reflect a promising outlook for clinical metagenomics. Methodological improvements, and convergence around protocols and best practises may improve performance in future.</p
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