288 research outputs found

    Vanishing of the integral of the Hurwitz zeta function

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    A proof is given that the improper Riemann integral of ÎŽ(s, a) with respect to the real parameter a, taken over the interval (0, 1], vanishes for all complex s with R(s) < 1. The integral does not exist (as a finite real number) when R(s) ≄ 1

    The Chang-Los-Suszko Theorem in a Topological Setting

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    The Chang-Ɓoƛ-Suszko theorem of first-order model theory characterizes universal-existential classes of models as just those elementary classes that are closed under unions of chains. This theorem can then be used to equate two model-theoretic closure conditions for elementary classes; namely unions of chains and existential substructures. In the present paper we prove a topological analogue and indicate some applications

    Reflection using the derivability conditions

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    Reflection principles are a way to build non-conservative true extensions of a theory. However the application of a reflection principle needs a proof predicate, and the effort needed to provide this is so great as to be not really practical. We look at a possible way to avoid this effort by using, instead of a proof predicate, a predicate defined using only necessary `modal' properties. Surprisingly, we can produce powerful non-conservative extensions this way. But a reflection principle based on such a predicate is essentially weaker, and we also consider its limitations

    Inequality Preserving Rationing

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    The present paper considers rationing problems interpreted as e.g. bankruptcy problems or taxation problems. We demonstrate that among the continuous and order-preserving rationing methods, theproportional method is the only rationing method that preserves inequality in both gains and losses.rationing; inequality preservation; taxation; manipulation; proportional method

    Marinomonas brasilensis sp. nov., isolated from the coral Mussismilia hispida, and reclassification of Marinomonas basaltis as a later heterotypic synonym of Marinomonas communis

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    A Gram-negative, aerobic bacterium, designated strain R-40503(T), was isolated from mucus of the reef-builder coral Mussismilia hispida, located in the Sao Sebastiao Channel, Sao Paulo, Brazil. Phylogenetic analyses revealed that strain R-40503(T) belongs to the genus Marinomonas. The 16S rRNA gene sequence similarity of R-40503(T) was above 97% with the type strains of Marinomonas vaga, M. basaltis, M. communis and M. pontica, and below 97% with type strains of the other Marinomonas species. Strain R-40503(T) showed less than 35% DNA-DNA hybridization (DDH) with the type strains of the phylogenetically closest Marinomonas species, demonstrating that it should be classified into a novel species. Amplified fragment length polymorphism (AFLP), chemotaxonomic and phenotypic analyses provided further evidence for the proposal of a novel species. Concurrently, a close genomic relationship between M. basaltis and M. communis was observed. The type strains of these two species showed 78% DDH and 63% AFLP pattern similarity. Their phenotypic features were very similar, and their DNA G+C contents were identical (46.3 mol%). Collectively, these data demonstrate unambiguously that Marinomonas basaltis is a later heterotypic synonym of Marinomonas communis. Several phenotypic features can be used to discriminate between Marinomonas species. The novel strain R-40503(T) is clearly distinguishable from its neighbours. For instance, it shows oxidase and urease activity, utilizes L-asparagine and has the fatty acid C(12:1) 3-OH but lacks C(10:0) and C(12:0). The name Marinomonas brasilensis sp. nov. is proposed, with the type strain R-40503(T) (=R-278(T) =LMG 25434(T) =CAIM 1459(T)). The DNA G+C content of strain R-40503(T) is 46.5 mol%

    Classical and numerical approaches to determining V-section band clamp axial stiffness

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    V-band clamp joints are used in a wide range of applications to connect circular flanges, for ducts, pipes and the turbocharger housing. Previous studies and research on V-bands are either purely empirical or analytical with limited applicability on the variety of V-band design and working conditions. In this paper models of the V-band are developed based on the classical theory of solid mechanics and the finite element method to study the behaviour of the V-bands under axial loading conditions. The good agreement between results from the developed FEA and the classical model support the suitability of the latter to model V-band joints with diameters greater than 110 mm under axial loading. The results from both models suggest that the axial stiffness for this V-band cross section reaches a peak value for V-bands with radius of approximately 150 mm across a wide range of coefficients of friction. Also, it is shown that the coefficient of friction and the wedge angle have a significant effect on the axial stiffness of V-bands

    On the construction of group invariant non expansive operators

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    In questa tesi vengono illustrati metodi di topologia computazionale negli ambiti di topological data analysis e shape comparison. Nello specifico, dato uno spazio topologico X e un sottogruppo G di Homeo(X), viene studiato un set di dati Ί composto da funzioni definite su X, continue e limitate, a valori reali. Per farlo si utilizzano degli operatori G-invarianti non espansivi (GINO), che si sono dimostrati efficaci per approssimare la pseudo-distanza naturale. In particolare in questo lavoro vengono studiati metodi per la costruzione di tali operatori, sfruttando le proprietĂ  algebriche delle variabili del problema. È importante osservare che il gruppo G viene sempre considerato come variabile, in quanto un cambio dell’osservatore puĂČ generalmente coincidere con un cambio dell’invarianza a cui si Ăš interessati

    Infinitely many securities and the fundamental theorem of asset pricing

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    Several authors have pointed out the possible absence of martingale measures for static arbitrage-free markets with an infinite number of available securities. This paper addresses this caveat by drawing on projective systems of probability measures. Firstly, it is shown that there are two distinct sorts of models whose treatment is necessarily different. Secondly, and more important, we analyze those situations for which one can provide a projective system of Ăł .additive measures whose projective limit may be interpreted as a risk-neutral probability. Hence, the Fundamental Theorem of Asset Pricing is extended so that it can apply for models with infinitely many assets

    The Relation Between Ejecta Velocity, Intrinsic Color, and Host-Galaxy Mass for High-Redshift Type Ia Supernovae

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    Recently, using a large low-redshift sample of Type Ia supernovae (SNe Ia), we discovered a relation between SN Ia ejecta velocity and intrinsic color that improves the distance precision of SNe Ia and reduces potential systematic biases related to dust reddening. No SN Ia cosmological results have yet made a correction for the "velocity-color" relation. To test the existence of such a relation and constrain its properties at high redshift, we examine a sample of 75 SNe Ia discovered and observed by the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey and Supernova Legacy Survey (SNLS). From each spectrum, we measure ejecta velocities at maximum brightness for the Ca H&K and Si II 6355 features, v_Ca^0 and v_Si^0, respectively. Using SN light-curve parameters, we determine the intrinsic B_max - V_max for each SN. Similar to what was found at low-redshift, we find that SNe Ia with higher ejecta velocity tend to be intrinsically redder than SNe Ia with lower ejecta velocity. The distributions of ejecta velocities for SNe Ia at low and high redshift are similar, indicating that current cosmological results should have little bias related to the velocity-color relation. Additionally, we find a slight (2.4-sigma significant) trend between SN Ia ejecta velocity and host-galaxy mass such that SNe Ia in high-mass host galaxies tend to have lower ejecta velocities as probed by v_Ca^0. These results emphasize the importance of spectroscopy for SN Ia cosmology.Comment: 13 pages, 11 figures, accepted by Ap
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