467,744 research outputs found

    Wobbling of a liquid column between unequal discs

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    One of the most puzzling results of an experiment on the stability of long liquid columns under microgravity, performed aboard Spacelab-D2 in 1993 and named STACO, aiming at the analysis of deformations of nearly cylindrical liquid columns under several mechanical disturbances, is revisited here. It corresponds to the unexplained breakage of an 85 mm long liquid bridge of low viscosity silicone oil, established between unequal discs of 30 and 28 mm, intended to counterbalance the expected deformation by residual acceleration found in previous flights, and left idle because the vibrations and oscillations to be applied afterwards were not started, for fear of premature breakage. A detailed image analysis is performed to extract the maximum amount of data, to be able to check against available theories for axisymmetric and non-axisymmetric deformations of a liquid column

    To Split or Not to Split, That Is the Question in Some Shallow Water Equations

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    In this paper we analyze the use of time splitting techniques for solving shallow water equation. We discuss some properties that these schemes should satisfy so that interactions between the source term and the shock waves are controlled. This paper shows that these schemes must be well balanced in the meaning expressed by Greenberg and Leroux [5]. More specifically, we analyze in what cases it is enough to verify an Approximate C-property and in which cases it is required to verify an Exact C-property (see [1], [2]). We also include some numerical tests in order to justify our reasoning

    The number of maximal torsion cosets in subvarieties of tori

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    We present sharp bounds on the number of maximal torsion cosets in a subvariety of the complex algebraic torus Gmn\mathbb{G}_{\textrm{m}}^n. Our first main result gives a bound in terms of the degree of the defining polynomials. A second result gives a bound in terms of the toric degree of the subvariety. As a consequence, we prove the conjectures of Ruppert and of Aliev and Smyth on the number of isolated torsion points of a hypersurface. These conjectures bound this number in terms of the multidegree and the volume of the Newton polytope of a polynomial defining the hypersurface, respectively.Comment: 21 page

    Lyric - keeper of the past : on the poetics of popular poetry in T. Percy's "Reliques of ancient poetry" and J. G. Herder's "Volkslieder"

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    Both Percy and Herder establish popular poetry within the horizon of modern literature, accentuating its strangeness compared to learned poetry or "Kunstdichtung". But there is a decisive difference between Percy's and Herder's handling of this strangeness. Percy tries to bridge the gap by way of historico-philological explanation and reconstruction. In the „Reliques“, he not only chooses, corrects and groups his poems. He also adds four historical essays to his edition […] and provides numerous introductory remarks, footnotes, bibliographical references, and glossaries of archaic words and idioms. Contrary to Percy, Herder preserves and even enforces the strangeness of the texts. On the other hand, he also wants his reader to bridge the gap […] through the modern reader's empathic grasping of the supposed archaic face-to-face-communication between poet-singer and audience. In order to reach this goal, the reader must try to supplement the fragmentary text through the intuition of the authentic situation in which the text originally was communicated. Such a supplement seems possible because popular poetry deals with stock situations common to all people. […] In order to reach this goal, by the way, Herder simulates in the „Auszug aus einem Briefwechsel“ and in the introduction to the „Volkslieder“ the same attitude which he wants to convey to his readers. Both essays display the rhetoric of an emphatic, fragmentary and consensual dialogue between friends

    Teleosemantics and Productivity

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    There has been much discussion of so-called teleosemantic approaches to the naturalisation of content. Such discussion, though, has been largely confined to simple, innate mental states with contents such as There is a fly here. Even assuming we can solve the issues that crop up at this stage, an account of the content of human mental states will not get too far without an account of productivity: the ability to entertain indefinitely many thoughts. \ud The best-known teleosemantic theory, Millikan’s biosemantics, offers an account of productivity in thought. This paper raises a basic worry about this account: that the use of mapping functions in the theory is unacceptable from a naturalistic point of view
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