9,265 research outputs found

    Regularity of Eigenstates in Regular Mourre Theory

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    The present paper gives an abstract method to prove that possibly embedded eigenstates of a self-adjoint operator HH lie in the domain of the kthk^{th} power of a conjugate operator AA. Conjugate means here that HH and AA have a positive commutator locally near the relevant eigenvalue in the sense of Mourre. The only requirement is Ck+1(A)C^{k+1}(A) regularity of HH. Regarding integer kk, our result is optimal. Under a natural boundedness assumption of the multiple commutators we prove that the eigenstate 'dilated' by exp(iθA)\exp(i\theta A) is analytic in a strip around the real axis. In particular, the eigenstate is an analytic vector with respect to AA. Natural applications are 'dilation analytic' systems satisfying a Mourre estimate, where our result can be viewed as an abstract version of a theorem due to Balslev and Combes. As a new application we consider the massive Spin-Boson Model.Comment: 27 page

    Network Models

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    Networks can be combined in various ways, such as overlaying one on top of another or setting two side by side. We introduce "network models" to encode these ways of combining networks. Different network models describe different kinds of networks. We show that each network model gives rise to an operad, whose operations are ways of assembling a network of the given kind from smaller parts. Such operads, and their algebras, can serve as tools for designing networks. Technically, a network model is a lax symmetric monoidal functor from the free symmetric monoidal category on some set to Cat\mathbf{Cat}, and the construction of the corresponding operad proceeds via a symmetric monoidal version of the Grothendieck construction.Comment: 46 page

    Genetic Aspects of Female Longevity

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    Longevity of the breeding female has both economic and animal welfare implications for the swine industry. High culling levels lead to increased replacement rates and reduce lifetime productivity for individual breeding females and the breeding herd. Greater replacement rates increase production costs related to purchase (or development), isolation, and acclimation of replacement females. PigCHAMP [1-5] summaries (Table 1) from 1998 through 2003, report annualized replacement rates of \u3e 50% and average herd parity of only 2.5 litters. Breeding herd productivity and economic sustainability are compromised when females are culled early in life and prior to achieving a positive return on investment. Breeding program design and genetic selection decisions clearly influence sow longevity and establish the base for a profitable, sustainable breeding herd
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