2,069 research outputs found

    Dominance-related seasonal song production is unrelated to circulating testosterone in a subtropical songbird

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    PublishedJournal ArticleCirculating testosterone (T) is widely considered to play a key role in the production of sexual displays by male vertebrates. While numerous studies support a role for circulating T in promoting the production of song in male birds, this understanding is based primarily on evidence from seasonally breeding northern temperate species, leaving it unclear whether this mechanism generalizes to other regions of the world. Here we investigate whether variation in circulating levels of T can explain the marked within- and among-individual variation in male song performance observed in a subtropical population of the year-round territorial white-browed sparrow weaver (Plocepasser mahali mahali). Our findings reveal that both circulating T and male song production peaked at a similar time point, halfway through the population-level breeding season. However, while dominant males were more likely to sing and sang for longer than subordinate males, within-group paired comparisons revealed no dominance-related differences in circulating T. Moreover, comparisons both among and within individual dominant males revealed that song duration, syllable rate and proportion of time spent singing were all unrelated to circulating T. Together, our findings suggest that natural variation in male song production, at least in this population of white-browed sparrow weavers, is achieved principally through mechanisms other than variation in circulating T concentration. More widely, our results are in line with the view that male song production is not exclusively regulated by gonadally synthesized steroids.J.E.Y. was supported by a University of Bristol Post-Graduate Scholarship, A.J.Y. and A.N.R. were supported by BBSRC David Phillips Research Fellowships (BB/H022716/1 and BB/C520555/1)

    The relationship timeline: A method for the study of shared lived experiences in relational contexts

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    Lifeline methods—graphic illustrations of the pathways of lived experience traveled by individuals from birth to anticipated death—have been useful in the study of lived experience. Existing lifeline methods and research focus on the individual experience; absent from this literature are the collective experiences of those in intimate relationships. In this paper, based on our research with 120 same-sex couples, we present a method to allow for the joint creation of relationship timelines, which serve as the basis for eliciting dyadic data in multiple forms: graphic representations of relationship development through couples’ creation of a timeline of key events and periods; qualitative narratives of couples’ shared experiences; and quantitative ratings of significant events and periods in their lives together. Lessons learned from the application of this Relationship Timeline Method are discussed, as are implications for future study of shared lived experiences in relational contexts

    Correlation between imaging and pathology in ductal carcinoma in situ of the breast

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    BACKGROUND: It is helpful in planning treatment for patients with ductal carcinoma in situ (DCIS) if the size and grade could be reliably predicted from the mammography. The aims of this study were to determine if the type of calcification can be best used to predict histopathological grade from the mammograms, to examine the association of mammographic appearance of DCIS with grade and to assess the correlation between mammographic size and pathological size. METHODS: Mammographic films and pathological slides of 115 patients treated for DCIS between 1986 and 2000 were reviewed and reclassified by a single radiologist and a single pathologist respectively. Prediction models for the European Pathologist Working Group (EPWG) and Van Nuys classifications were generated by ordinal regression. The association between mammographic appearance and grade was tested with the χ(2)-test. Relation of mammographic size with pathological size was established using linear regression. The relation was expressed by the correlation coefficient (r). RESULTS: The EPWG classification was correctly predicted in 68%, and the Van Nuys classification in 70% if DCIS was presented as microcalcifications. High grade was associated with presence of linear calcifications (p < 0.001). Association between mammograhic- and pathological size was better for DCIS presented as microcalcifications (r = 0.89, p < 0.001) than for DCIS presented as a density (r = 0.77, p < 0.001). CONCLUSIONS: Prediction of histopathological grade of DCIS presenting as microcalcifications is comparable using the Van Nuys and EPWG classification. There is no strict association of mammographic appearance with histopathological grade. There is a better linear relation between mammographic- and pathological size of DCIS presented as microcalcifications than as a density, although both relations are statistically significant

    Evaluation of ecosystem-based marine management strategies based on risk assessment

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    Abstract This study presents a comprehensive and generic framework that provides a typology for the identification and selection of consistently defined ecosystem-based management measures and allows a coherent evaluation of these measures based on their performance to achieve policy objectives. The performance is expressed in terms of their reduction of risk of an adverse impact on the marine ecosystem. This typology consists of two interlinked aspects of a measure, i.e. the “Focus” and the “Type”. The “Focus” is determined by the part of the impact chain (Driver–Pressure–State) the measure is supposed to mitigate or counteract. The “Type” represents the physical measure itself in terms of how it affects the impact chain directly; we distinguish Spatio-temporal distribution controls, Input and Output controls, Remediation and Restoration measures. The performance of these measures in terms of their reduction in risk of adverse impacts was assessed based on an explicit consideration of three time horizons: past, present and future. Application of the framework in an integrated management strategy evaluation of a suite of measures, shows that depending on the time horizon, different measures perform best. “Past” points to measures targeting persistent pressures (e.g. marine litter) from past activities. “Present” favors measures targeting a driver (e.g. fisheries) that has a high likelihood of causing adverse impacts. “Future” involves impacts that both have a high likelihood of an adverse impact, as well as a long time to return to pre-impacted condition after the implementation of appropriate management, e.g. those caused by permanent infrastructure or persistent pressures such as marine litter or specific types of pollution

    Ruthenacycles and Iridacycles as Catalysts for Asymmetric Transfer Hydrogenation and Racemisation

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    Ruthenacycles, which are easily prepared in a single step by reaction between enantiopure aromatic amines and [Ru(arene)Cl2]2 in the presence of NaOH and KPF6, are very good asymmetric transfer hydrogenation catalysts. A range of aromatic ketones were reduced using isopropanol in good yields with ee’s up to 98%. Iridacycles, which are prepared in similar fashion from [IrCp*Cl2]2 are excellent catalysts for the racemisation of secondary alcohols and chlorohydrins at room temperature. This allowed the development of a new dynamic kinetic resolution of chlorohydrins to the enantiopure epoxides in up to 90% yield and 98% enantiomeric excess (ee) using a mutant of the enzyme Haloalcohol dehalogenase C and an iridacycle as racemisation catalyst.

    Dialogue games for explaining medication choices

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    SMT solvers can be used efficiently to search for optimal paths across multiple graphs when optimising for certain resources. In the medical context, these graphs can represent treatment plans for chronic conditions where the optimal paths across all plans under consideration are the ones which minimize adverse drug interactions. The SMT solvers, however, work as a black-box model and there is a need to justify the optimal plans in a human-friendly way. We aim to fulfill this need by proposing explanatory dialogue protocols based on computational argumentation to increase the understanding and trust of humans interacting with the system. The protocols provide supporting reasons for nodes in a path and also allow counter reasons for the nodes not in the graph, highlighting any potential adverse interactions during the dialogue.Postprin

    A Review of the Theoretical Basis, Effects, and Cost Effectiveness of Online Smoking Cessation Interventions in the Netherlands: A Mixed-Methods Approach

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    Background: Tobacco smoking is a worldwide public health problem. In 2015, 26.3% of the Dutch population aged 18 years and older smoked, 74.4% of them daily. More and more people have access to the Internet worldwide; approximately 94% of the Dutch population have online access. Internet-based smoking cessation interventions (online cessation interventions) provide an opportunity to tackle the scourge of tobacco. Objective: The goal of this paper was to provide an overview of online cessation interventions in the Netherlands, while exploring their effectivity, cost effectiveness, and theoretical basis. Methods: A mixed-methods approach was used to identify Dutch online cessation interventions, using (1) a scientific literature search, (2) a grey literature search, and (3) expert input. For the scientific literature, the Cochrane review was used and updated by two independent researchers (n=651 identified studies), screening titles, abstracts, and then full-text studies between 2013 and 2016 (CENTRAL, MEDLINE, and EMBASE). For the grey literature, the researchers conducted a Google search (n=100 websites), screening for titles and first pages. Including expert input, this resulted in six interventions identified in the scientific literature and 39 interventions via the grey literature. Extracted data included effectiveness, cost effectiveness, theoretical factors, and behavior change techniques used. Results: Overall, many interventions (45 identified) were offered. Of the 45 that we identified, only six that were included in trials provided data on effectiveness. Four of these were shown to be effective and cost effective. In the scientific literature, 83% (5/6) of these interventions included changing attitudes, providing social support, increasing self-efficacy, motivating smokers to make concrete action plans to prepare their attempts to quit and to cope with challenges, supporting identity change and advising on changing routines, coping, and medication use. In all, 50% (3/6) of the interventions included a reward for abstinence. Interventions identified in the grey literature were less consistent, with inclusion of each theoretical factor ranging from 31% to 67% and of each behavior change technique ranging from 28% to 54%. Conclusions: Although the Internet may provide the opportunity to offer various smoking cessation programs, the user is left bewildered as far as efficacy is concerned, as most of these data are not available nor offered to the smokers. Clear regulations about the effectiveness of these interventions need to be devised to avoid disappointment and failed quitting attempts. Thus, there is a need for policy regulations to regulate the proliferation of these interventions and to foster their quality in the Netherlands.Mir
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