2,001 research outputs found

    Studies on the Mannosylphosphate transfer in Saccharomyces cerevisiae

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    Thesis (Ph. D. in Science)--University of Tsukuba, (A), no. 1794, 1998.3.2

    On the nonexistence of Liouvillian first integrals for generalized Liénard polynomial differential systems

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    International audienceWe consider generalized Liénard polynomial differential systems. In their work, Llibre and Valls have shown that, except in some particular cases, such systems have no Liouvillian first integral. In this letter, we give a direct and shorter proof of this result

    Number and Amplitude of Limit Cycles emerging from {\it Topologically Equivalent} Perturbed Centers

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    We consider three examples of weekly perturbed centers which do not have {\it geometrical equivalence}: a linear center, a degenerate center and a non-hamiltonian center. In each case the number and amplitude of the limit cycles emerging from the period annulus are calculated following the same strategy: we reduce of all of them to locally equivalent perturbed integrable systems of the form: dH(x,y)+ϵ(f(x,y)dyg(x,y)dx)=0dH(x,y)+\epsilon(f(x,y)dy-g(x,y)dx)=0, with H(x,y)=1/2(x2+y2)H(x,y)={1/2}(x^2+y^2). This reduction allows us to find the Melnikov function, M(h)=H=hfdygdxM(h)=\int_{H=h}fdy-gdx, associated to each particular problem. We obtain the information on the bifurcation curves of the limit cycles by solving explicitly the equation M(h)=0M(h)=0 in each case.Comment: 17 pages, 0 figure

    Molecular Dynamics Simulation Study of Nonconcatenated Ring Polymers in a Melt: I. Statics

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    Molecular dynamics simulations were conducted to investigate the structural properties of melts of nonconcatenated ring polymers and compared to melts of linear polymers. The longest rings were composed of N=1600 monomers per chain which corresponds to roughly 57 entanglement lengths for comparable linear polymers. For the rings, the radius of gyration squared was found to scale as N to the 4/5 power for an intermediate regime and N to the 2/3 power for the larger rings indicating an overall conformation of a crumpled globule. However, almost all beads of the rings are "surface beads" interacting with beads of other rings, a result also in agreement with a primitive path analysis performed in the following paper (DOI: 10.1063/1.3587138). Details of the internal conformational properties of the ring and linear polymers as well as their packing are analyzed and compared to current theoretical models.Comment: 15 pages, 14 figure

    New α-amylase and trypsin inhibitors among the CM-proteins of barley (Hordeum vulgare)

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    Barley CM-proteins are a group of at least five salt-soluble components (CMa-e) that can be selectively extracted from endosperm with chloroform/methanol mixtures. N-terminal sequences of proteins CMa, CMb and CMc have been determined and found to be homologous to those previously determined for CMd and CMc, an observation which confirms that their structural genes are members of a dispersed multi-gene family. The purified CM-proteins were tested against trypsin and against α-amylases from saliva, pancreas, Aspergillus oryzae, Tenebrio molitor and barley. Besides CMe, which was known to be a trypsin inhibitor, CMc also showed antitrypsin activity, whereas CMa was specifically active against the α-amylase from T. molitor and no inhibitory activity was found for proteins CMb and CMd. The evolutionary implications of these findings are discusse

    Learning to Teach and Assess Problem Solving in Animal Sciences

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    Poster presented at the Assessment for Curricular Improvement Poster Exhibit 2023.Exploring curriculum assessment is an exciting but daunting activity, especially when you first dive in. Faculty are currently reviewing the Animal Sciences BS program to better meet the needs of their students in an ever-changing field. Student learning outcomes and curriculum mapping will be evaluated and updated in the spirit of simplification and streamlining. In one content-heavy course, problem-solving skills will be emphasized. Different methods of assessment of problem-solving skills will be utilized, and the results will be presented
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