1,457 research outputs found

    Height Protest

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    They called her Mitzi...

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    Textbook Affordability Open Course: Facilitator Guide and D2L Course Materials

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    This guide will help facilitators of the Textbook Affordability Open Course organize and implement the content in their own learning environment. The designers of the course have included items that need to be updated and personalized for each implementation of the course as well as helpful tips for successful implementation. This course is an introduction to textbook affordability, open educational resources, and other open practices that impact equity in our classrooms. While it is geared towards higher education faculty, the concepts and practices covered here can be used in any teaching and learning scenario. This course will explore concepts tied to the one cost factor teachers can control - course materials - and relate that directly to increasing equitable practice in the classroom. By the end of the course, you will have explored your own library for options for course materials, searched for open educational resources in your content area, discovered other open practices that may be useful to your own teaching, and defined how equity and course material cost are related

    Diet of Mesozoic toothed birds (Longipterygidae) inferred from quantitative analysis of extant avian diet proxies

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    BackgroundBirds are key indicator species in extant ecosystems, and thus we would expect extinct birds to provide insights into the nature of ancient ecosystems. However, many aspects of extinct bird ecology, particularly their diet, remain obscure. One group of particular interest is the bizarre toothed and long-snouted longipterygid birds. Longipterygidae is the most well-understood family of enantiornithine birds, the dominant birds of the Cretaceous period. However, as with most Mesozoic birds, their diet remains entirely speculative.ResultsTo improve our understanding of longipterygids, we investigated four proxies in extant birds to determine diagnostic traits for birds with a given diet: body mass, claw morphometrics, jaw mechanical advantage, and jaw strength via finite element analysis. Body mass of birds tended to correspond to the size of their main food source, with both carnivores and herbivores splitting into two subsets by mass: invertivores or vertivores for carnivores, and granivores + nectarivores or folivores + frugivores for herbivores. Using claw morphometrics, we successfully distinguished ground birds, non-raptorial perching birds, and raptorial birds from one another. We were unable to replicate past results isolating subtypes of raptorial behaviour. Mechanical advantage was able to distinguish herbivorous diets with particularly high values of functional indices, and so is useful for identifying these specific diets in fossil taxa, but overall did a poor job of reflecting diet. Finite element analysis effectively separated birds with hard and/or tough diets from those eating foods which are neither, though could not distinguish hard and tough diets from one another. We reconstructed each of these proxies in longipterygids as well, and after synthesising the four lines of evidence, we find all members of the family but Shengjingornis (whose diet remains inconclusive) most likely to be invertivores or generalist feeders, with raptorial behaviour likely in Longipteryx and Rapaxavis.ConclusionsThis study provides a 20% increase in quantitatively supported fossil bird diets, triples the number of diets reconstructed in enantiornithine species, and serves as an important first step in quantitatively investigating the origins of the trophic diversity of living birds. These findings are consistent with past hypotheses that Mesozoic birds occupied low trophic levels

    Neighborhood Conditions and Psychosocial Outcomes Among Middle-Aged African Americans: A Cross-sectional Analysis

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    Objective: We examined associations between observed neighborhood conditions (good/adverse) and psychosocial outcomes (stress, depressive symptoms, resilience, and sense of control) among middle-aged and older African Americans. Methods: The sample included 455 middle-aged and older African Americans examined in Wave 10 of the African American Health (AAH) study. Linear regression was adjusted for attrition, self-selection into neighborhoods, and potential confounders, and stratified by the duration at current address (5 years at current residence despite being associated with better psychosocial outcomes

    Daughterless homodimer synergizes with Eyeless to induce Atonal expression and retinal neuron differentiation

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    AbstractClass I Basic Helix-Loop-Helix (bHLH) transcription factors form homodimers or heterodimers with class II bHLH proteins. While bHLH heterodimers are known to have diverse roles, little is known about the role of class I homodimers. In this manuscript, we show that a linked dimer of Daughterless (Da), the only Drosophila class I bHLH protein, activates Atonal (Ato) expression and retinal neuron differentiation synergistically with the retinal determination factor Eyeless (Ey). The HLH protein Extramacrocheate (Emc), which forms heterodimer with Da, antagonizes the synergistic activation from Da but not the Da–Da linked dimer with Ey. We show that Da directly interacts with Ey and promotes Ey binding to the Ey binding site in the Ato 3׳ enhancer. Interestingly, the Ey binding site in the Ato 3׳ enhancer contains an embedded E-box that is also required for the synergistic activation by Ey and Da. Finally we show that mammalian homologs of Ey and Da can functionally replace their Drosophila counterparts to synergistically activate the Ato enhancer, suggesting that the observed function is evolutionary conserved

    Trophic diversity and evolution in Enantiornithes: a synthesis including new insights from Bohaiornithidae

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    Enantiornithines were the dominant birds of the Mesozoic, but understanding of their diet is still tenuous. We introduce new data on the enantiornithine family Bohaiornithidae, famous for their large size and powerfully built teeth and claws. In tandem with previously published data, we comment on the breadth of enantiornithine ecology and potential patterns in which it evolved. Body mass, jaw mechanical advantage, finite element analysis of the jaw, and traditional morphometrics of the claws and skull are compared between bohaiornithids and living birds. We find bohaiornithids to be more ecologically diverse than any other enantiornithine family: Bohaiornis and Parabohaiornis are similar to living plant-eating birds; Longusunguis resembles raptorial carnivores; Zhouornis is similar to both fruit-eating birds and generalist feeders; and Shenqiornis and Sulcavis plausibly ate fish, plants, or a mix of both. We predict the ancestral enantiornithine bird to have been a generalist which ate a wide variety of foods. However, more quantitative data from across the enantiornithine tree is needed to refine this prediction. By the Early Cretaceous, enantiornithine birds had diversified into a variety of ecological niches like crown birds after the K-Pg extinction, adding to the evidence that traits unique to crown birds cannot completely explain their ecological success

    Quantitative investigation of pengornithid enantiornithine diet reveals macrocarnivorous ecology evolved in birds by Early Cretaceous

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    The diet of Mesozoic birds is poorly known, limiting evolutionary understanding of birds’ roles in modern ecosystems. Pengornithidae is one of the best understood families of Mesozoic birds, hypothesized to eat insects or only small amounts of meat. We investigate these hypotheses with four lines of evidence: estimated body mass, claw traditional morphometrics, jaw mechanical advantage, and jaw finite element analysis. Owing to limited data, the diets of Eopengornis and Chiappeavis remain obscure. Pengornis, Parapengornis, and Yuanchuavis show adaptations for vertebrate carnivory. Pengornis also has talons similar to living raptorial birds like caracaras that capture and kill large prey, which represents the earliest known adaptation for macrocarnivory in a bird. This supports the appearance of this ecology ∼35 million years earlier than previously thought. These findings greatly increase the niche breadth known for Early Cretaceous birds, and shift the prevailing view that Mesozoic birds mainly occupied low trophic levels

    Disassociated rhamphotheca of fossil bird Confuciusornis informs early beak reconstruction, stress regime, and developmental patterns

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    Soft tissue preservation in fossil birds provides a rare window into their anatomy, function, and development. Here, we present an exceptionally-preserved specimen of Confuciusornis which, through Laser-Stimulated Fluorescence imaging, is identified as preserving a disassociated rhamphotheca. Reconstruction of the in vivo position of the rhamphotheca validates the association of the rhamphotheca with two previous confuciusornithid specimens while calling that of a third specimen into question. The ease of dissociation is discussed and proposed with a fourth specimen alongside finite element analysis as evidence for preferential soft-food feeding. However, this proposition remains tentative until there is a better understanding of the functional role of beak attachment in living birds. Differences in post-rostral extent and possibly rhamphotheca curvature between confuciusornithids and modern birds hint at developmental differences between the two. Together, this information provides a wealth of new information regarding the nature of the beak outside crown Aves

    Towards Semantic Service Request of Web Service Composition

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