37,832 research outputs found

    Production and nutritional composition of two annual ryegrass cultivars (Diploid and Tetraploid)

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    The feed cost represents the major cost in milk production. Direct grazing and forage produced on the dairy farm could allow the farmer to a better feed production cost control. Ryegrass have been extensively used for grazing and forage production. This study evaluates the production and nutritional composition of two ryegrass cultivars diploid and tetraploid alone or in a binary mixture (50:50). The results showed that the binary mixture is a good option because of its higher production of DM/ha, higher ME and NFC and lower content of NDF, ADF and ADL.info:eu-repo/semantics/publishedVersio

    Share the Fame or Share the Blame? The Reputational Implications of Partnerships

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    We use an adverse selection model to study the dynamics of ?rms?reputations when ?rms implement joint projects. We show that in contrast with projects implemented by a single ?rm, in the case of joint projects a ?rm?s reputation does not necessarily increase following a success and does not necessarily decrease following a failure. We also study how reputation considerations a¤ect ?rms? decisions to participate in joint projects. We show that a high quality partner may not be preferable to a low quality partner, and that a high reputation partner is not necessarily preferable to a low reputation partner. JEL codes: L14, L15, L24, D82, D85

    Local quantum ergodic conjecture

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    The Quantum Ergodic Conjecture equates the Wigner function for a typical eigenstate of a classically chaotic Hamiltonian with a delta-function on the energy shell. This ensures the evaluation of classical ergodic expectations of simple observables, in agreement with Shnirelman's theorem, but this putative Wigner function violates several important requirements. Consequently, we transfer the conjecture to the Fourier transform of the Wigner function, that is, the chord function. We show that all the relevant consequences of the usual conjecture require only information contained within a small (Planck) volume around the origin of the phase space of chords: translations in ordinary phase space. Loci of complete orthogonality between a given eigenstate and its nearby translation are quite elusive for the Wigner function, but our local conjecture stipulates that their pattern should be universal for ergodic eigenstates of the same Hamiltonian lying within a classically narrow energy range. Our findings are supported by numerical evidence in a Hamiltonian exhibiting soft chaos. Heavily scarred eigenstates are remarkable counter-examples of the ergodic universal pattern.Comment: 4 figure

    Testing the Equivalence of Regular Languages

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    The minimal deterministic finite automaton is generally used to determine regular languages equality. Antimirov and Mosses proposed a rewrite system for deciding regular expressions equivalence of which Almeida et al. presented an improved variant. Hopcroft and Karp proposed an almost linear algorithm for testing the equivalence of two deterministic finite automata that avoids minimisation. In this paper we improve the best-case running time, present an extension of this algorithm to non-deterministic finite automata, and establish a relationship between this algorithm and the one proposed in Almeida et al. We also present some experimental comparative results. All these algorithms are closely related with the recent coalgebraic approach to automata proposed by Rutten

    Radiative corrections in bumblebee electrodynamics

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    We investigate some quantum features of the bumblebee electrodynamics in flat spacetimes. The bumblebee field is a vector field that leads to a spontaneous Lorentz symmetry breaking. For a smooth quadratic potential, the massless excitation (Nambu-Goldstone boson) can be identified as the photon, transversal to the vacuum expectation value of the bumblebee field. Besides, there is a massive excitation associated with the longitudinal mode and whose presence leads to instability in the spectrum of the theory. By using the principal-value prescription, we show that no one-loop radiative corrections to the mass term is generated. Moreover, the bumblebee self-energy is not transverse, showing that the propagation of the longitudinal mode can not be excluded from the effective theory.Comment: Revised version: contains some more elaborated interpretation of the results. Conclusions improve

    A percolation system with extremely long range connections and node dilution

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    We study the very long-range bond-percolation problem on a linear chain with both sites and bonds dilution. Very long range means that the probability pijp_{ij} for a connection between two occupied sites i,ji,j at a distance rijr_{ij} decays as a power law, i.e. pij=ρ/[rijαN1α]p_{ij} = \rho/[r_{ij}^\alpha N^{1-\alpha}] when 0α<1 0 \le \alpha < 1, and pij=ρ/[rijln(N)]p_{ij} = \rho/[r_{ij} \ln(N)] when α=1\alpha = 1. Site dilution means that the occupancy probability of a site is 0<ps10 < p_s \le 1. The behavior of this model results from the competition between long-range connectivity, which enhances the percolation, and site dilution, which weakens percolation. The case α=0\alpha=0 with ps=1p_s =1 is well-known, being the exactly solvable mean-field model. The percolation order parameter PP_\infty is investigated numerically for different values of α\alpha, psp_s and ρ\rho. We show that in the ranges 0α1 0 \le \alpha \le 1 and 0<ps10 < p_s \le 1 the percolation order parameter PP_\infty depends only on the average connectivity γ\gamma of sites, which can be explicitly computed in terms of the three parameters α\alpha, psp_s and ρ\rho
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