880 research outputs found

    Writing and Adapting Instruction During the Time of Covid-19

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    Writing and teaching writing during the early parts of the Covid-19 pandemic presented a number of challenges. This article explores a few challenges and possibilities to address the teaching of writing

    Impact resistance of composite fan blades

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    The resistance of current-design Pratt and Whitney Aircraft low aspect ratio advanced fiber reinforced epoxy matrix composite fan blades to foreign object damage (FOD) at STOL operating conditions was investigated. Five graphite/epoxy and five boron/epoxy wide chord fan blades with nickel plated stainless steel leading edge sheath protection were fabricated and impact tested. The fan blades were individually tested in a vacuum whirlpit under FOD environments. The FOD environments were typical of those encountered in service operations. The impact objects were ice balls, gravel, stralings and gelatin simulated birds. Results of the damage sustained from each FOD impact are presented for both the graphite boron reinforced blades. Tests showed that the present design composite fan blades, with wrap around leading edge protection have inadequate FOD impact resistance at 244 m/sec (800 ft/sec) tip speed, a possible STOL operating condition

    Unpacking Writer Identity: How Beliefs and Practices Inform Writing Instruction

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    Although identity research is common in educational studies, little research explores the connections between identity and pedagogy, and far fewer specifically examine how writer identity influences writing pedagogy. Additional research exploring the connection between writer identity and writing pedagogy is necessary to offer nuanced teaching strategies to strengthen writing pedagogy. The present study explores the connections between writer identity and writing pedagogy for three preservice English teachers with strong writer identities during their respective student teaching experiences. Interview data were utilized to explore writer identity and analyse connections to writing pedagogy through In Vivo coding in this narrative inquiry. Findings revealed participant writer identities strongly influenced their writing pedagogy, influencing the design, beliefs, and goals for writing activity. This study supports the literature that drawing from personal writer identity is an effective way to approach the teaching of writing in secondary writing classrooms

    Metastasis: Wherefore Arf Thou?

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    SummaryThe small GTP-binding protein Arf6 is known to be an important regulator of the actin cytoskeleton and of cell motility associated with metastasis. A recent study identifies yet another role for Arf6 in metastasis — as a regulator of plasma-membrane-derived microvesicle release

    Preservice Teacher Writer Identities: Tensions and Implications

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    Because of recent attention underscoring the lack of preservice teachers’ (PSTs) writer identities , the purpose of this manuscript is to learn more about the writer identities of two PSTs, how to uncover the tensions that exist therein, and how they intend to enact that writer identity in the secondary classroom. This multiple case study examines the writer identity of two PSTs from a midwestern university in the United States. Data collection included a visual metaphorical representation, participant generated reflections in class, and participate generated reflections in practicum. The data suggest that contrasting writer identities exist among preservice ELA teachers and that PSTs can have multiple writer identities that are at odds with each other. One focal participant saw the potential harm of a structured approach to writing instruction that challenged her beliefs and values on writing and writing instruction. Another focal participant wrestled with a separate account of a structured approach to writing instruction, understanding the practical needs in an era of standardized testing while recognizing that such instruction can be limiting. This manuscript reveals the importance of identity work in preservice teacher education courses by asking PSTs to reflect on and later to interrogate their writer identities, contrasting their discoveries with the research on writer-teacher education

    Emergence and Phenomenology in Quantum Gravity

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    In this thesis we investigate two approaches to quantum gravity. The first is the emergence of gravity from a discrete fundamental theory, and the second is the direct quantisation of gravity. For the first we develop tools to determine with relatively high accuracy the speed of propagation of information in collective modes which ultimately should give us some information about the emergent causal structure. We found a way of finding the dependence on the relative interaction strengths of the Hamiltonian and we also managed to calculate this speed in the case where the operators in the Hamitonian were not necessarily bounded. For the second approach, we investigated the phenomenology of Loop Quantum Gravity. We found that ultra light black holes (lighter than the Planck mass) have interesting new properties on top of being non-singular. First their horizon is hidden behind a Plancksized wormhole, second their specific heat capacity is positive and they are quasi-stable, they take an infinite amount of time evaporate. We investigated the dynamics of their collapse and evaporation explicitly seeing that not only was there no singularity, but there is also no information loss problem. Looking at how primordial black holes were in existence, we found that they might account for a significant portion of dark matter. And if they did, their radiation spectrum is such that the black holes in the dark matter halo of our galaxy could be the source for the ultra high energy cosmic rays we observe on earth

    Lieb-Robinson bounds for commutator-bounded operators

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    We generalize the Lieb-Robinson theorem to systems whose Hamiltonian is the sum of local operators whose commutators are bounded

    Multiple endocytic pathways of G protein-coupled receptors delineated by GIT1 sensitivity.

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    Recently, we identified a GTPase-activating protein for the ADP ribosylation factor family of small GTP-binding proteins that we call GIT1. This protein initially was identified as an interacting partner for the G protein-coupled receptor kinases, and its overexpression was found to affect signaling and internalization of the prototypical beta(2)-adrenergic receptor. Here, we report that GIT1 overexpression regulates internalization of numerous, but not all, G protein-coupled receptors. The specificity of the GIT1 effect is not related to the type of G protein to which a receptor couples, but rather to the endocytic route it uses. GIT1 only affects the function of G protein-coupled receptors that are internalized through the clathrin-coated pit pathway in a beta-arrestin- and dynamin-sensitive manner. Furthermore, the GIT1 effect is not limited to G protein-coupled receptors because overexpression of this protein also affects internalization of the epidermal growth factor receptor. However, constitutive agonist-independent internalization is not regulated by GIT1, because transferrin uptake is not affected by GIT1 overexpression. Thus, GIT1 is a protein involved in regulating the function of signaling receptors internalized through the clathrin pathway and can be used as a diagnostic tool for defining the endocytic pathway of a receptor
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