13,675 research outputs found

    Opportunities for the development of organic data collection and processing based on Finnish experiences

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    The Plant Production Inspection Centre is one of the Finnish state authorities in charge of implementation of the inspection system laid down in Council Regulation 2092/91. It keeps the register of all organic farms and co-ordinates the inspection work managed by regional control bodies

    Improved Estimates for the Parameters of the Heavy Quark Expansion

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    We give improved estimates for the non-perturbative parameters appearing in the heavy quark expansion for inclusive decays. While the parameters appearing in low orders of this expansion can be extracted from data, the number of parameters in higher orders proliferates strongly, making a determination of these parameters from data impossible. Thus, one has to rely on theoretical estimates which may be obtained from an insertion of intermediate states. In this paper we refine this method and attempt to estimate the uncertainties of this approach.Comment: 18 pages (v2: Fixed sign error in section 3. conclusions unchanged

    Topologically non-trivial magnon bands in artificial square spin ices subject to Dzyaloshinskii-Moriya interaction

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    Systems that exhibit topologically protected edge states are interesting both from a fundamental point of view as well as for potential applications, the latter because of the absence of back-scattering and robustness to perturbations. It is desirable to be able to control and manipulate such edge states. Here, we show that artificial square ices can incorporate both features: an interfacial Dzyaloshinksii-Moriya gives rise to topologically non-trivial magnon bands, and the equilibrium state of the spin ice is reconfigurable with different configurations having different magnon dispersions and topology. The topology is found to develop as odd-symmetry bulk and edge magnon bands approach each other, so that constructive band inversion occurs in reciprocal space. Our results show that topologically protected bands are supported in square spin ices.Comment: 27 pages, 6 figure

    Flat forms, bi-Lipschitz parametrizations, and smoothability of manifolds

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    We give a sufficient condition for a metric (homology) manifold to be locally bi-Lipschitz equivalent to an open subset in \rn. The condition is a Sobolev condition for a measurable coframe of flat 1-forms. In combination with an earlier work of D. Sullivan, our methods also yield an analytic characterization for smoothability of a Lipschitz manifold in terms of a Sobolev regularity for frames in a cotangent structure. In the proofs, we exploit the duality between flat chains and flat forms, and recently established differential analysis on metric measure spaces. When specialized to \rn, our result gives a kind of asymptotic and Lipschitz version of the measurable Riemann mapping theorem as suggested by Sullivan

    How sharp are PV measures?

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    Properties of sharp observables (normalized PV measures) in relation to smearing by a Markov kernel are studied. It is shown that for a sharp observable PP defined on a standard Borel space, and an arbitrary observable MM, the following properties are equivalent: (a) the range of PP is contained in the range of MM; (b) PP is a function of MM; (c) PP is a smearing of MM.Comment: 9 page

    Acceptance of mobile services - insights from the Swedish market for mobile telephony

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    The main purpose of the paper is to investigate young peoples’ perspectives on mobile services in order to shed light on the acceptance of mobile services. The knowledge of and interest in mobile services of individuals using such services is analyzed. A second objective is to investigate the reasons for using/not using mobile services. In-depth focus group interviews and secondary empirical data provide the main data. Concerning the youth’s general knowledge of and interest in mobile services, the results point to six things: young people show a low demand for many mobile services, there is a demand for extended, established mobile services, like SMS, the interest in the new services vary, there is low interest in active information search, there is little knowledge of the enabling technology, and the understanding of the pricing is generally low. As concerns reasons for and against usage of mobile services, results point to four central aspects: many individuals could present clearly defined needs for certain services, many indicated an interest in "community usage" of mobile services, they experienced the prices of mobile services to be a hinder for usage, and technology placed limitations on the usage. The paper discusses practical implications on the acceptance of mobile services.Mobile services; mobility; focus groups; telecommunications; wireless; knowledge
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