9,762 research outputs found

    ZRT1 harbors an excess of nonsynonymous polymorphism and shows evidence of balancing selection in Saccharomyces cerevisiae

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    Estimates of the fraction of nucleotide substitutions driven by positive selection vary widely across different species. Accounting for different estimates of positive selection has been difficult, in part because selection on polymorphism within a species is known to obscure a signal of positive selection between species. While methods have been developed to control for the confounding effects of negative selection against deleterious polymorphism, the impact of balancing selection on estimates of positive selection has not been assessed. In Saccharomyces cerevisiae, there is no signal of positive selection within protein coding sequences as the ratio of nonsynonymous to synonymous polymorphism is higher than that of divergence. To investigate the impact of balancing selection on estimates of positive selection we examined five genes with high rates of nonsynonymous polymorphism in S. cerevisiae relative to divergence from S. paradoxus. One of the genes, a high affinity zinc transporter ZRT1, shows an elevated rate of synonymous polymorphism indicative of balancing selection. The high rate of synonymous polymorphism coincides with nonsynonymous divergence between three haplotype groups, which we find to be functionally indistinguishable. We conclude that balancing selection is not likely to be a common cause of genes harboring a large excess of nonsynonymous polymorphism in yeast

    Self heating and nonlinear current-voltage characteristics in bilayer graphene

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    We demonstrate by experiments and numerical simulations that the low-temperature current-voltage characteristics in diffusive bilayer graphene (BLG) exhibit a strong superlinearity at finite bias voltages. The superlinearity is weakly dependent on doping and on the length of the graphene sample. This effect can be understood as a result of Joule heating. It is stronger in BLG than in monolayer graphene (MLG), since the conductivity of BLG is more sensitive to temperature due to the higher density of electronic states at the Dirac point.Comment: 9 pages, 7 figures, REVTeX 4.

    Characeae of Nebraska

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    The object of this resulting paper is to review the Characeae already published for the state and to report additional collections

    The Impact of Classical Configurations on Complexity Theory

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    The implications of low-energy models have been far-reaching and pervasive. Given the current status of optimal models, information theorists urgently desire the synthesis of fiber-optic cables, demonstrates the extensive importance of programming languages. This is essential to the success of our work. In order to overcome this issue, we validate that even though XML and the UNIVAC computer can interact to fulfill this ambition, voice-over- IP can be made event-driven, modular, and stable

    Seasonal Roads

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    Lynn Kimball Fay has been publishing for twenty-five years under the pen-name L. E. Kimball.As a writer, I’m interested in the way Truth seems to me—intuitively—nonlinea. I’m interested in story cycles that examine Truth from different points of view, usually nonlinearly; and I’m interested in the way setting reveals Truth and how it reveals character. I’m interested in Faith—a kind that is not irreconcilable with science, the kind it takes to put that foot in front of the other.The kind we have in one another.I have always, therefore, been fascinated with layers of Time, the nonlinear and synchronistic way in which we experience it. How the people and events in our lives float up to us periodically, much like those Halloween apples we bobbed for in our childhood, seemingly randomly, yet never quite that, informing and forever changing the direction of our lives, so that at times we don’t understand the significance of things until we’re “meant to.” The past, present and even implied future become part of an Einsteinian reality in ways we can never anticipate.My linked stories reflect these ideas.I write as I live

    Isomonodromic deformatiion with an irregular singularity and hyperelliptic curve

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    In this paper, we extend the result of Kitaev and Korotkin to the case where a monodromy-preserving deformation has an irregular singularity. For the monodromy-preserving deformation, we obtain the τ\tau-function whose deformation parameters are the positions of regular singularities and the parameter tt of an irregular singularity. Furthermore, the τ\tau-function is expressed by the hyperelliptic Θ\Theta function moving the argument \z and the period \B, where tt and the positions of regular singularities move zz and \B, respectively.Comment: 23 pages, 2 figure

    Bivariant long exact sequences II

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    Given a pair of short exact sequences 1) 0 → X → Y → Z → 0, 0 → A → B → C → 0 in an abelian category A, with sufficiently many projectives and injectives, and given an additive bifunctor T we show that T applied to the pair (1) gives rise to a diagram of a type described by C. T. C. Wall that contains 15 interlocking long exact sequences involving the derived functors of T at (A, X), (A, Y), etc. and also involving the derived functors of Tp and Tq which are two functors with domain A2 that arise through the failure of T to preserve pullbacks and pushouts. In the case of Hom (respectively þ) in the category of G-modules for a group G the derived functors of Tp (respectively Tq) are expressed in terms of group cohomology (respectively homology)

    Effect of spin orbit scattering on the magnetic and superconducting properties of nearly ferromagnetic metals: application to granular Pt

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    We calculate the effect of scattering on the static, exchange enhanced, spin susceptibility and show that in particular spin orbit scattering leads to a reduction of the giant moments and spin glass freezing temperature due to dilute magnetic impurities. The harmful spin fluctuation contribution to the intra-grain pairing interaction is strongly reduced opening the way for BCS superconductivity. We are thus able to explain the superconducting and magnetic properties recently observed in granular Pt as due to scattering effects in single small grains.Comment: 9 pages 3 figures, accepted for publication in Phys. Rev. Letter

    Harmonic Maa{\ss}-Jacobi forms of degree 1 with higher rank indices

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    We define and investigate real analytic weak Jacobi forms of degree 1 and arbitrary rank. En route we calculate the Casimir operator associated to the maximal central extension of the real Jacobi group, which for rank exceeding 1 is of order 4. In ranks exceeding 1, the notions of H-harmonicity and semi-holomorphicity are the same.Comment: 28 page
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