5,376 research outputs found

    Shallow-water residency and limited dispersal of Atlantic halibut in the Gulf of Maine

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    • Atlantic halibut (Hippoglossus hippoglossus), once abundant in the Gulf of Maine (GOM) on the northeast coast, were overfished until the stock collapsed in the 1940s. • In 2007, a three-year tagging study using electronic tags was done by the Maine Dept. of Marine Resources. • The objective of the study was to determine if GOM halibut migrate to spawning grounds on the Scotian Shelf and mix with Canadian halibut stock

    An End to Federal Funding of For-Profit Charter Schools?

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    In Arizona State Board for Charter Schools v. U.S. Department of Education, the Ninth Circuit validated a U.S. Department of Education policy that for-profit charter schools are ineligible for federal funding under the Individuals with Disabilities Education Act and Title I of the Elementary and Secondary Education Act. That policy now threatens to chill the growth of charter schools in states that would have otherwise encouraged their expansion. This Note examines the details of the Ninth Circuit\u27s decision, its effect on states that allow for-profit charter schools, and its impact on the charter school movement

    Validation and Improvement of the Beef Production Sub-index in Ireland for Beef Cattle

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    End of project reportThe objectives of the following study were to: a. Quantify the effect of sire genetic merit for BCI on: 1. feed intake, growth and carcass traits of progeny managed under bull or steer beef production systems. 2. live animal scores, carcass composition and plasma hormone and metabolite concentrations in their progeny. b. Compare the progeny of : 1. Late-maturing beef with dairy breeds and 2. Charolais (CH), Limousin (LM), Simmental (SM) and Belgian Blue (BB) sires bred to beef suckler dams, for feed intake, blood hormones and metabolites, live animal measurements, carcass traits and carcass value in bull and steer production systems

    An Infinite Dimensional Symmetry Algebra in String Theory

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    Symmetry transformations of the space-time fields of string theory are generated by certain similarity transformations of the stress-tensor of the associated conformal field theories. This observation is complicated by the fact that, as we explain, many of the operators we habitually use in string theory (such as vertices and currents) have ill-defined commutators. However, we identify an infinite-dimensional subalgebra whose commutators are not singular, and explicitly calculate its structure constants. This constitutes a subalgebra of the gauge symmetry of string theory, although it may act on auxiliary as well as propagating fields. We term this object a {\it weighted tensor algebra}, and, while it appears to be a distant cousin of the WW-algebras, it has not, to our knowledge, appeared in the literature before.Comment: 14 pages, Plain TeX, report RU93-8, CTP-TAMU-2/94, CERN-TH.7022/9

    Averaging Property of Wedge Product and Naturality in Discrete Exterior Calculus

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    In exterior calculus on smooth manifolds, the exterior derivative and wedge product are natural with respect to smooth maps between manifolds, that is, these operations commute with pullback. In discrete exterior calculus (DEC), simplicial cochains play the role of discrete forms, the coboundary operator serves as the discrete exterior derivative, and the antisymmetrized cup product provides a discrete wedge product. We show that these discrete operations in DEC are natural with respect to abstract simplicial maps. A second contribution is a new averaging interpretation of the discrete wedge product in DEC. We also show that this wedge product is the same as Wilson's cochain product defined using Whitney and de Rham maps.Comment: arXiv admin note: substantial text overlap with arXiv:2104.10277. Note from authors in response to arXiv admin note: The material in this submission was split off from arXiv:2104.10277 and version 2 of arXiv:2104.10277 does not contain the material in this submission. This revision includes material about cochain product using Whitney forms and connection to C-infinity algebra

    Characterization of hepcidin response to holotransferrin in novel recombinant TfR1 HepG2 cells

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    Hepcidin is the key regulator of systemic iron homeostasis. The iron-sensing mechanisms and the role of intracellular iron in modulating hepatic hepcidin secretion are unclear. Therefore, we created a novel cell line, recombinant-TfR1 HepG2,expressing iron-response-element-independent TFRC mRNA to promote cellular iron overload and examined the effect of excess holotransferrin (5 g/L) on cell-surface TfR1, iron content, hepcidin secretion and mRNA expressions of TFRC, HAMP, SLC40A1,HFE and TFR2. Results showed that the recombinant cells exceeded levels of cell surface TfR1 in wild-type cells under basal (2.8-fold; p<0.03) and holotransferrin supplemented conditions for 24 h and 48 h (4.4- and 7.5-fold, respectively; p<0.01). Also, these cells showed higher intracellular iron content than wild-type cells under basal (3-fold; p<0.03) and holotransferrin-supplemented conditions (6.6-fold at 4 h; p<0.01). However, hepcidin secretion was not higher than wild-type cells. Moreover, holotransferrin treatment to recombinant cells did not elevate HAMP responses compared to untreated or wild-type cells. In conclusion, increased intracellular iron content in recombinant cells did not increase hepcidin responses compared to wild-type cells, resembling hemochromatosis. Furthermore, TFR2 expression altered within 4 h of treatment, while HFE expression altered later at 24 h and 48 h, suggesting that TFR2 may function prior to HFE in HAMP regulation
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