32,538 research outputs found

    Inhibition of DNA ejection from bacteriophage by Mg+2 counterions

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    The problem of inhibiting viral DNA ejection from bacteriophages by multivalent counterions, specifically Mg+2^{+2} counterions, is studied. Experimentally, it is known that MgSO4_4 salt has a strong and non-monotonic effect on the amount of DNA ejected. There exists an optimal concentration at which the minimum amount of DNA is ejected from the virus. At lower or higher concentrations, more DNA is ejected from the capsid. We propose that this phenomenon is the result of DNA overcharging by Mg+2^{+2} multivalent counterions. As Mg+2^{+2} concentration increases from zero, the net charge of DNA changes from negative to positive. The optimal inhibition corresponds to the Mg+2^{+2} concentration where DNA is neutral. At lower/higher concentrations, DNA genome is charged. It prefers to be in solution to lower its electrostatic self-energy, which consequently leads to an increase in DNA ejection. By fitting our theory to available experimental data, the strength of DNA−-DNA short range attraction energies, mediated by Mg+2^{+2}, is found to be −-0.004 kBTk_BT per nucleotide base. This and other fitted parameters agree well with known values from other experiments and computer simulations. The parameters are also in aggreement qualitatively with values for tri- and tetra-valent counterions.Comment: 17 pages, 4 figures, improved manuscript. Submitted to J. Chem. Phys (2010

    Identities for hyperelliptic P-functions of genus one, two and three in covariant form

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    We give a covariant treatment of the quadratic differential identities satisfied by the P-functions on the Jacobian of smooth hyperelliptic curves of genera 1, 2 and 3

    Linking multiple biodiversity informatics platforms with Darwin Core Archives

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    This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article.NHM Repositor

    Acoustic-Phonetic Characteristics of Clear Speech in Bilinguals

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    This study examined the language-dependency of clear speech modifications by comparing the clear speech strategies of late bilinguals in both their L1 (Finnish) and L2 (English). Results generally supported the hypothesis of language-independent enhancement of global clear speech modifications, but language-dependent segmental enhancement. The global clear speech strategies produced by Finnish-English bilinguals in their L2 (English) were similar in the extent of the modifications to those of native English speakers, indicating a surprising flexibility of the non-native speech production system

    Deriving bases for Abelian functions

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    We present a new method to explicitly define Abelian functions associated with algebraic curves, for the purpose of finding bases for the relevant vector spaces of such functions. We demonstrate the procedure with the functions associated with a trigonal curve of genus four. The main motivation for the construction of such bases is that it allows systematic methods for the derivation of the addition formulae and differential equations satisfied by the functions. We present a new 3-term 2-variable addition formulae and a complete set of differential equations to generalise the classic Weierstrass identities for the case of the trigonal curve of genus four.Comment: 35page

    Exact solutions for a class of integrable Henon-Heiles-type systems

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    We study the exact solutions of a class of integrable Henon-Heiles-type systems (according to the analysis of Bountis et al. (1982)). These solutions are expressed in terms of two-dimensional Kleinian functions. Special periodic solutions are expressed in terms of the well-known Weierstrass function. We extend some of our results to a generalized Henon-Heiles-type system with n+1 degrees of freedom.Comment: RevTeX4-1, 13 pages, Submitted to J. Math. Phy
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