26 research outputs found

    Oldest pathology in a tetrapod bone illuminates the origin of terrestrial vertebrates

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    The origin of terrestrial tetrapods was a key event in vertebrate evolution, yet how and when it occurred remains obscure, due to scarce fossil evidence. Here, we show that the study of palaeopathologies, such as broken and healed bones, can help elucidate poorly understood behavioural transitions such as this. Using high-resolution finite element analysis, we demonstrate that the oldest known broken tetrapod bone, a radius of the primitive stem tetrapod Ossinodus pueri from the mid-Viséan (333 million years ago) of Australia, fractured under a high-force, impact-type loading scenario. The nature of the fracture suggests that it most plausibly occurred during a fall on land. Augmenting this are new osteological observations, including a preferred directionality to the trabecular architecture of cancellous bone. Together, these results suggest that Ossinodus, one of the first large (>2m length) tetrapods, spent a significant proportion of its life on land. Our findings have important implications for understanding the temporal, biogeographical and physiological contexts under which terrestriality in vertebrates evolved. They push the date for the origin of terrestrial tetrapods further back into the Carboniferous by at least two million years. Moreover, they raise the possibility that terrestriality in vertebrates first evolved in large tetrapods in Gondwana rather than in small European forms, warranting a re-evaluation of this important evolutionary event

    One thousand plant transcriptomes and the phylogenomics of green plants

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    Abstract: Green plants (Viridiplantae) include around 450,000–500,000 species1, 2 of great diversity and have important roles in terrestrial and aquatic ecosystems. Here, as part of the One Thousand Plant Transcriptomes Initiative, we sequenced the vegetative transcriptomes of 1,124 species that span the diversity of plants in a broad sense (Archaeplastida), including green plants (Viridiplantae), glaucophytes (Glaucophyta) and red algae (Rhodophyta). Our analysis provides a robust phylogenomic framework for examining the evolution of green plants. Most inferred species relationships are well supported across multiple species tree and supermatrix analyses, but discordance among plastid and nuclear gene trees at a few important nodes highlights the complexity of plant genome evolution, including polyploidy, periods of rapid speciation, and extinction. Incomplete sorting of ancestral variation, polyploidization and massive expansions of gene families punctuate the evolutionary history of green plants. Notably, we find that large expansions of gene families preceded the origins of green plants, land plants and vascular plants, whereas whole-genome duplications are inferred to have occurred repeatedly throughout the evolution of flowering plants and ferns. The increasing availability of high-quality plant genome sequences and advances in functional genomics are enabling research on genome evolution across the green tree of life

    Tinnitus handicap inventory for evaluating treatment effects: which changes are clinically relevant?

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    OBJECTIVE: To determine the minimum change of the Tinnitus Handicap Inventory (THI) score that could be considered clinically relevant, the authors compared the absolute change of the THI with the Clinical Global Impression–Improvement (CGI-I) score. STUDY DESIGN: International studies register with standardized data collection. SETTING: Tinnitus Research Initiative (TRI). SUBJECTS AND METHODS: Two hundred ten patients of the TRI database were eligible for this study. In the first analysis, the THI score change and CGI-I ratings were compared with equipercentile linking. In a second analysis, the authors categorized the CGI-I into the 4 groups much better or better, minimally better, no change, and worse and calculated the corresponding differences of the THI score and the effect sizes. An effect size separating the minimally better and the no-change groups was chosen, and the referring THI mean score difference was calculated. RESULTS: According to the linking method, a CGI-I value of 3 (minimally better) corresponded to a THI score reduction of 6 to 16, whereas the CGI-I value of 4 (no change) corresponded to the range between improvement by 5 points and worsening by 4 points. For separating the no-change and minimally better groups, an effect size d = 0.5 was determined, resulting in a minimal clinically relevant difference of ΔTHI = 7. CONCLUSION: Two different methods yielded comparable results in identifying a reduction in the THI score of 6 and 7 points, respectively, as the minimal clinically relevant change. This study provides a first orientation for sample size calculations and for planning the design of future studies

    Do masks terminate the icon?

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    Iconic memory is operationally defined by part-report experiments (Sperling, 1960). If a mask is presented after the target, the mask is thought to be superposed on the target in the iconic representation, or to displace it from the representation. But could a cue presented after a pattern mask still allow selection within the target array? A target array of letters was followed by a checkerboard mask. We compared two target-mask interstimulus intervals (ISIs; 0 and 100 ms), and six cue delays. At ISI = 0 ms, performance was at chance, for part report and whole report. At ISI = 100 ms, with the shortest cue delay, observers demonstrated a part-report advantage of 25-30%. As cue delay increased the part-report advantage decreased. These results are inconsistent with an iconic memory that is automatically displaced or overwritten by new information. We consider two alternatives: a second-stage store, which represents letters in terms of their high-level features and which the mask cannot penetrate, or a four-dimensional store that preserves separately the representations of the target and its aftercoming mask. We discuss the implications of our results for studies that use backward masking to "terminate the icon"
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