5,678 research outputs found

    Learning about the Energy of a Hurricane System through an Estimation Epistemic Game

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    As part of a study into students' problem solving behaviors, we asked upper-division physics students to solve estimation problems in clinical interviews. We use the Resources Framework and epistemic games to describe students' problem solving moves. We present a new epistemic game, the "estimation epistemic game". In the estimation epistemic game, students break the larger problem into a series of smaller, tractable problems. Within each sub-problem, they try to remember a method for solving the problem, and use estimation and reasoning abilities to justify their answers. We demonstrate how a single case study student plays the game to estimate the total energy in a hurricane. Finally, we discuss the implications of epistemic game analysis for other estimation problems.Comment: 4 pages. Submitted to Physics Education Research Conference 201

    Regurgitative food transfer among wild wolves

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    Few studies of monogamous canids have addressed regurgitation in the context of extended parental care and alloparental care within family groups. We studied food transfer by regurgitation in a pack of wolves on Ellesmere Island, North West Territories, Canada, during 6 summers from 1988 through 1996. All adult wolves, including yearlings and a post-reproductive female, regurgitated food. Although individuals regurgitated up to five times per bout, the overall ratio of regurgitations per bout was 1.5. Pups were more likely to receive regurgitations (81%) than the breeding female (14%) or auxiliaries (6%). The breeding male regurgitated mostly to the breeding female and pups, and the breeding female regurgitated primarily to pups. The relative effort of the breeding female was correlated with litter size (Kendall’s τ = 0.93, P = 0.01). Peu d’études ont abordĂ© la question de la rĂ©gurgitation en relation avec les soins parentaux et alloparentaux au sein des familles chez les canidĂ©s monogames. Nous avons Ă©tudiĂ© le transfert de la nourriture par rĂ©gurgitation au sein d’une meute de loups de l’üle d’Ellesmere, Territoires du Nord-Ouest, Canada, durant six Ă©tĂ©s, de 1988 Ă  la fin de 1996. Tous les loups adultes, y compris les jeunes de 1 an et les femelles post-parturientes, rĂ©gurgitaient de la nourriture. Certains individus rĂ©gurgitaient jusqu’à 5 fois par Ă©pisode, mais, dans l’ensemble, le nombre de rĂ©gurgitations par Ă©pisode Ă©tait de 1,5. Les petits Ă©taient plus susceptibles de recevoir des rĂ©gurgitations (81%) que les femelles reproductrices (14%) ou les auxiliaires (6%). Les mĂąles reproducteurs rĂ©gurgitaient Ă  leur partenaire et Ă  leurs petits et les femelles reproductrices rĂ©gurgitaient surtout Ă  leurs petits. L’effort relatif des femelles Ă©tait en corrĂ©lation avec le nombre de petits dans leur portĂ©e (τ de Kendall = 0,93, P = 0,01)

    Integrated design of superconducting accelerator magnets

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    This chapter introduces the main features of the ROXIE program which has been developed for the design of the superconducting magnets for the Large Hadron Collider (LHC) at CERN. The program combines numerical field calculation with a reduced vector-potential formulation, the application of vector-optimization methods, and the use of genetic as well as deterministic minimization algorithms. Together with the applied concept of features, the software is used as an approach towards integrated design of superconducting magnets. The main quadrupole magnet for the LHC, was chosen as an example for the integrated design process. (17 refs)

    Complete Nucleotide Sequence of the Chloroplast Genome from a Leptosporangiate Fer, Adiantum capillus-veneris L.

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    We determined the complete nucleotide sequence of the chloroplast genome of the leptosporangiate fern, Adiantum capillus-veneris L. (Pteridaceae). The circular genome is 150,568 bp, with a large single-copy region (LSC) of 82,282 bp, a small-single copy region (SSC) of 21,392 bp and inverted repeats (IR) of 23,447 bp each. We compared the sequence to other published chloroplast genomes to infer the location of putative genes. When the IR is considered only once, we assigned 118 genes, of which 85 encode proteins, 29 encode tRNAs and 4 encode rRNAs. Four protein-coding genes, all four rRNA genes and six tRNA genes occur in the IR. Most (57) putative protein-coding genes appear to start with an ATG codon, but we also detected five other possible start codons, some of which suggest tRNA editing. We also found 26 apparent stop codons in 18 putative genes, also suggestive of RNA editing. We found all but one of the tRNA genes necessary to encode the complete repertoire required for translation. The missing trnK gene appears to have been disrupted by a large inversion, relative to other published chloroplast genomes. We detected several structural rearrangements that may provide useful information for phylogenetic studies

    High Frequency of Extra-Pair Paternity in Eastern Kingbirds

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    Genetic parentage in the socially monogamous and territorial Eastern Kingbird( Tyrannust tyrannus) was examined in a central New York population by multilocus DNA fingerprinting. Extra-pair young were identified in 60% (12 of 20) of nests. Of the 64 nestlings profiled, 42% were sired by extra-pair males, but no cases of conspecific brood parasitism were detected. These results are markedly different from a previous electrophoretic study of the same species in a Michigan population, which reported 39% of nestlings were unrelated to one (typically the mother, quasiparasitismo)r both (conspecificb roodp arasitism) of the putative parents. In the New York population, extra-pairp aternityw as most common among females that returned to breed on a former territory. Among females that were new to a breeding territory, extrapair paternity increased directly with breeding density. Although the power of the tests was low, neither breeding synchrony nor male experience with a breeding territory appeared to be associated with the occurrence of extra-pair young

    Improved test of Lorentz Invariance in Electrodynamics using Rotating Cryogenic Sapphire Oscillators

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    We present new results from our test of Lorentz invariance, which compares two orthogonal cryogenic sapphire microwave oscillators rotating in the lab. We have now acquired over 1 year of data, allowing us to avoid the short data set approximation (less than 1 year) that assumes no cancelation occurs between the Îș~e−\tilde{\kappa}_{e-} and Îș~o+\tilde{\kappa}_{o+} parameters from the photon sector of the standard model extension. Thus, we are able to place independent limits on all eight Îș~e−\tilde{\kappa}_{e-} and Îș~o+\tilde{\kappa}_{o+} parameters. Our results represents up to a factor of 10 improvement over previous non rotating measurements (which independently constrained 7 parameters), and is a slight improvement (except for Îș~e−ZZ\tilde{\kappa}_{e-}^{ZZ}) over results from previous rotating experiments that assumed the short data set approximation. Also, an analysis in the Robertson-Mansouri-Sexl framework allows us to place a new limit on the isotropy parameter PMM=ή−ÎČ+1/2P_{MM}=\delta-\beta+{1/2} of 9.4(8.1)×10−119.4(8.1)\times10^{-11}, an improvement of a factor of 2.Comment: Accepted for publication in Phys. Rev.

    Factors to Consider in Improving Prescription Drug Pharmacy Leaflets

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    Today, when consumers receive prescription drug pharmacy leaflets (also known as ‘consumer medication information’ or CMI), they often appear in small font size, with cluttered layouts, and distracting information. This problem has attracted the attention of the U.S. Food and Drug Administration in advocating for more comprehendible, accurate, and easy-to-access CMI formats. Our study of four different CMI prototypes shows that an expanded Over-the-Counter (OTC) Drug Facts prototype is the best for improving comprehension accuracy, and is especially effective for those with lower health literacy and health motivation. A simpler OTC prototype did not aid accuracy scores due in part to its lack of complexity; whereas the most complex prototype (the revised medication guide – similar to most CMI today) reduced leaflet likability and usage intentions. Finally, continued leaflet availability improved accuracy scores for lower health literacy and health motivation respondents. Implications for marketing and public health policy are offered

    The Selaginella Genome Identifies Changes in Gene Content Associated With the Evolution of Vascular Plants

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    Vascular plants appeared ~410 million years ago, then diverged into several lineages of which only two survive: the euphyllophytes (ferns and seed plants) and the lycophytes. We report here the genome sequence of the lycophyte Selaginella moellendorffii (Selaginella), the first nonseed vascular plant genome reported. By comparing gene content in evolutionarily diverse taxa, we found that the transition from a gametophyte- to a sporophyte-dominated life cycle required far fewer new genes than the transition from a nonseed vascular to a flowering plant, whereas secondary metabolic genes expanded extensively and in parallel in the lycophyte and angiosperm lineages. Selaginella differs in posttranscriptional gene regulation, including small RNA regulation of repetitive elements, an absence of the trans-acting small interfering RNA pathway, and extensive RNA editing of organellar genes
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