1,669 research outputs found

    Leaves of High Yielding Perennial Ryegrass Contain Less Aggregated Rubisco Than S23

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    Breeding diploid perennial ryegrass for improved dry matter yield under nitrogen-limiting conditions has reduced the nitrogen (N) concentration of the herbage (Wilkins et al., 2003). Reduced N concentration in the ruminant diet is one potential way to reduce losses of N to the environment by reducing the amount of N that animals excrete. The underlying physiological basis of this increased N-use efficiency in ryegrass was investigated

    Leaves of High Yielding Perennial Ryegrass Contain Less Aggregated Rubisco than S23

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    Breeding diploid perennial ryegrass for improved dry matter yield under nitrogen-limiting conditions has reduced the nitrogen (N) concentration of the herbage (Wilkins et al., 2003). Reduced N concentration in the ruminant diet is one potential way to reduce losses of N to the environment by reducing the amount of N that animals excrete. The underlying physiological basis of this increased N-use efficiency in ryegrass was investigated

    Smart cable for design of high density metallic cross connect systems

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    The present invention to provide a smart cable system for high density metallic cross connect systems. In particular, this invention relates to the physical structure of cables and associated hardware needed to form the smart cable system for interconnecting cards in shelves and racks of high density metallic cross connect switching systems. This invention provides the cable installer the ability to connect cables to cards with minimal errors by using visual indicators. The visual indicators guide the cable installer such that he/she can properly install the cables into the appropriate connectors. The present invention also provides a means for detecting when and where the cables are connected within the cross connect system

    Group classification of heat conductivity equations with a nonlinear source

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    We suggest a systematic procedure for classifying partial differential equations invariant with respect to low dimensional Lie algebras. This procedure is a proper synthesis of the infinitesimal Lie's method, technique of equivalence transformations and theory of classification of abstract low dimensional Lie algebras. As an application, we consider the problem of classifying heat conductivity equations in one variable with nonlinear convection and source terms. We have derived a complete classification of nonlinear equations of this type admitting nontrivial symmetry. It is shown that there are three, seven, twenty eight and twelve inequivalent classes of partial differential equations of the considered type that are invariant under the one-, two-, three- and four-dimensional Lie algebras, correspondingly. Furthermore, we prove that any partial differential equation belonging to the class under study and admitting symmetry group of the dimension higher than four is locally equivalent to a linear equation. This classification is compared to existing group classifications of nonlinear heat conductivity equations and one of the conclusions is that all of them can be obtained within the framework of our approach. Furthermore, a number of new invariant equations are constructed which have rich symmetry properties and, therefore, may be used for mathematical modeling of, say, nonlinear heat transfer processes.Comment: LaTeX, 51 page

    Reduction Operators of Linear Second-Order Parabolic Equations

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    The reduction operators, i.e., the operators of nonclassical (conditional) symmetry, of (1+1)-dimensional second order linear parabolic partial differential equations and all the possible reductions of these equations to ordinary differential ones are exhaustively described. This problem proves to be equivalent, in some sense, to solving the initial equations. The ``no-go'' result is extended to the investigation of point transformations (admissible transformations, equivalence transformations, Lie symmetries) and Lie reductions of the determining equations for the nonclassical symmetries. Transformations linearizing the determining equations are obtained in the general case and under different additional constraints. A nontrivial example illustrating applications of reduction operators to finding exact solutions of equations from the class under consideration is presented. An observed connection between reduction operators and Darboux transformations is discussed.Comment: 31 pages, minor misprints are correcte

    Group Analysis of Variable Coefficient Diffusion-Convection Equations. I. Enhanced Group Classification

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    We discuss the classical statement of group classification problem and some its extensions in the general case. After that, we carry out the complete extended group classification for a class of (1+1)-dimensional nonlinear diffusion--convection equations with coefficients depending on the space variable. At first, we construct the usual equivalence group and the extended one including transformations which are nonlocal with respect to arbitrary elements. The extended equivalence group has interesting structure since it contains a non-trivial subgroup of non-local gauge equivalence transformations. The complete group classification of the class under consideration is carried out with respect to the extended equivalence group and with respect to the set of all point transformations. Usage of extended equivalence and correct choice of gauges of arbitrary elements play the major role for simple and clear formulation of the final results. The set of admissible transformations of this class is preliminary investigated.Comment: 25 page

    Enhanced Group Analysis and Exact Solutions of Variable Coefficient Semilinear Diffusion Equations with a Power Source

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    A new approach to group classification problems and more general investigations on transformational properties of classes of differential equations is proposed. It is based on mappings between classes of differential equations, generated by families of point transformations. A class of variable coefficient (1+1)-dimensional semilinear reaction-diffusion equations of the general form f(x)ut=(g(x)ux)x+h(x)umf(x)u_t=(g(x)u_x)_x+h(x)u^m (m0,1m\ne0,1) is studied from the symmetry point of view in the framework of the approach proposed. The singular subclass of the equations with m=2m=2 is singled out. The group classifications of the entire class, the singular subclass and their images are performed with respect to both the corresponding (generalized extended) equivalence groups and all point transformations. The set of admissible transformations of the imaged class is exhaustively described in the general case m2m\ne2. The procedure of classification of nonclassical symmetries, which involves mappings between classes of differential equations, is discussed. Wide families of new exact solutions are also constructed for equations from the classes under consideration by the classical method of Lie reductions and by generation of new solutions from known ones for other equations with point transformations of different kinds (such as additional equivalence transformations and mappings between classes of equations).Comment: 40 pages, this is version published in Acta Applicanda Mathematica

    SNFing HIV transcription

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    The SWI/SNF chromatin remodeling complex is an essential regulator of transcription of cellular genes. HIV-1 infection induces exit of a core component of SWI/SNF, Ini1, into the cytoplasm and its association with the viral pre-integration complex. Several recent papers published in EMBO Journal, Journal of Biological Chemistry, and Retrovirology provide new information regarding possible functions of Ini1 and SWI/SNF in HIV life cycle. It appears that Ini1 has an inhibitory effect on pre-integration steps of HIV replication, but also contributes to stimulation of Tat-mediated transcription. This stimulation involves displacement of the nucleosome positioned at the HIV promoter

    New results on group classification of nonlinear diffusion-convection equations

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    Using a new method and additional (conditional and partial) equivalence transformations, we performed group classification in a class of variable coefficient (1+1)(1+1)-dimensional nonlinear diffusion-convection equations of the general form f(x)ut=(D(u)ux)x+K(u)ux.f(x)u_t=(D(u)u_x)_x+K(u)u_x. We obtain new interesting cases of such equations with the density ff localized in space, which have large invariance algebra. Exact solutions of these equations are constructed. We also consider the problem of investigation of the possible local trasformations for an arbitrary pair of equations from the class under consideration, i.e. of describing all the possible partial equivalence transformations in this class.Comment: LaTeX2e, 19 page

    State-of-the-art in product service-systems

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    A Product Service-System (PSS) is an integrated combination of products and services. This western concept embraces a service-led competitive strategy, environmental sustainability, and the basis to differentiate from competitors who simply offer lower priced products. This paper aims to report the state-of-the-art of PSS research by presenting a clinical review of literature currently available on this topic. The literature is classified and the major outcomes of each study are addressed and analysed. On this basis, this paper defines the PSS concept, reports on its origin and features, gives examples of applications along with potential benefits and barriers to adoption, summarises available tools and methodologies, and identifies future research challenges
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