80 research outputs found

    Weyl group multiple Dirichlet series constructed from quadratic characters

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    We construct multiple Dirichlet series in several complex variables whose coefficients involve quadratic residue symbols. The series are shown to have an analytic continuation and satisfy a certain group of functional equations. These are the first examples of an infinite collection of unstable Weyl group multiple Dirichlet series in greater than two variables.Comment: incorporated referee's comment

    Peripheral and central employment of acid-sensing ion channels during early bilaterian evolution

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    Nervous systems are endowed with rapid chemosensation and intercellular signaling by ligand-gated ion channels (LGICs). While a complex, bilaterally symmetrical nervous system is a major innovation of bilaterian animals, the employment of specific LGICs during early bilaterian evolution is poorly understood. We therefore questioned bilaterian animals’ employment of acid-sensing ion channels (ASICs), LGICs that mediate fast excitatory responses to decreases in extracellular pH in vertebrate neurons. Our phylogenetic analysis identified an earlier emergence of ASICs from the overarching DEG/ENaC (degenerin/epithelial sodium channel) superfamily than previously thought and suggests that ASICs were a bilaterian innovation. Our broad examination of ASIC gene expression and biophysical function in each major bilaterian lineage of Xenacoelomorpha, Protostomia, and Deuterostomia suggests that the earliest bilaterian ASICs were probably expressed in the periphery, before being incorporated into the brain as it emerged independently in certain deuterostomes and xenacoelomorphs. The loss of certain peripheral cells from Ecdysozoa after they separated from other protostomes likely explains their loss of ASICs, and thus the absence of ASICs from model organisms Drosophila and Caenorhabditis elegans. Thus, our use of diverse bilaterians in the investigation of LGIC expression and function offers a unique hypothesis on the employment of LGICs in early bilaterian evolution.publishedVersio

    Vaginal Flora in Postmenopausal Women: The Effect of Estrogen Replacement

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    Objective:To determine the effect of estrogen replacement therapy (ERT) on the vaginal flora of postmenopausal women

    Molecular evidence for a single origin of ultrafiltration-based excretory organs

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    Under embargo until: 2021-06-23Excretion is an essential physiological process, carried out by all living organisms, regardless of their size or complexity.1, 2, 3 Both protostomes (e.g., flies and flatworms) and deuterostomes (e.g., humans and sea urchins) possess specialized excretory organs serving that purpose. Those organs exhibit an astonishing diversity, ranging from units composed of just few distinct cells (e.g., protonephridia) to complex structures, built by millions of cells of multiple types with divergent morphology and function (e.g., vertebrate kidneys).4,5 Although some molecular similarities between the development of kidneys of vertebrates and the regeneration of the protonephridia of flatworms have been reported,6,7 the molecular underpinnings of the development of excretory organs have never been systematically studied in a comparative context.4 Here, we show that a set of transcription factors (eya, six1/2, pou3, sall, lhx1/5, and osr) and structural proteins (nephrin, kirre, and zo1) is expressed in the excretory organs of a phoronid, brachiopod, annelid, onychophoran, priapulid, and hemichordate that represent major protostome lineages and non-vertebrate deuterostomes. We demonstrate that the molecular similarity observed in the vertebrate kidney and flatworm protonephridia6,7 is also seen in the developing excretory organs of those animals. Our results show that all types of ultrafiltration-based excretory organs are patterned by a conserved set of developmental genes, an observation that supports their homology. We propose that the last common ancestor of protostomes and deuterostomes already possessed an ultrafiltration-based organ that later gave rise to the vast diversity of extant excretory organs, including both proto- and metanephridia.acceptedVersio

    How Effective Were the Federal Reserve Emergency Liquidity Facilities?

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    Evidence from the Asset-Backed Commercial Paper Money Market Mutual Fund Liquidity Facilit

    Asymmetric function theory

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    The classical theory of symmetric functions has a central position in algebraic combinatorics, bridging aspects of representation theory, combinatorics, and enumerative geometry. More recently, this theory has been fruitfully extended to the larger ring of quasisymmetric functions, with corresponding applications. Here, we survey recent work extending this theory further to general asymmetric polynomials.Comment: 36 pages, 8 figures, 1 table. Written for the proceedings of the Schubert calculus conference in Guangzhou, Nov. 201

    Capacitating Community: The Writing Innovation Symposium

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    The topic of this symposium, capacitating community, invites CLJ readers to consider what makes a community possible. This piece showcases one means, small conferences, via a retrospective on the Writing Innovation Symposium (WIS), a regional event with national scope that has hosted writers and writing educators annually in Milwaukee, WI, since 2018. Through a quilted conversation pieced from hours of small-group discussion, twenty-nine participants across academic and nonacademic ranks, roles, and ranges of experience offer insight into the WIS as well as the nature and value of professional community
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