3,943 research outputs found

    Non-rigidity of spherical inversive distance circle packings

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    We give a counterexample of Bowers-Stephenson's conjecture in the spherical case: spherical inversive distance circle packings are not determined by their inversive distances.Comment: 6 pages, one pictur

    Minimal surfaces and particles in 3-manifolds

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    We use minimal (or CMC) surfaces to describe 3-dimensional hyperbolic, anti-de Sitter, de Sitter or Minkowski manifolds. We consider whether these manifolds admit ``nice'' foliations and explicit metrics, and whether the space of these metrics has a simple description in terms of Teichm\"uller theory. In the hyperbolic settings both questions have positive answers for a certain subset of the quasi-Fuchsian manifolds: those containing a closed surface with principal curvatures at most 1. We show that this subset is parameterized by an open domain of the cotangent bundle of Teichm\"uller space. These results are extended to ``quasi-Fuchsian'' manifolds with conical singularities along infinite lines, known in the physics literature as ``massive, spin-less particles''. Things work better for globally hyperbolic anti-de Sitter manifolds: the parameterization by the cotangent of Teichm\"uller space works for all manifolds. There is another description of this moduli space as the product two copies of Teichm\"uller space due to Mess. Using the maximal surface description, we propose a new parameterization by two copies of Teichm\"uller space, alternative to that of Mess, and extend all the results to manifolds with conical singularities along time-like lines. Similar results are obtained for de Sitter or Minkowski manifolds. Finally, for all four settings, we show that the symplectic form on the moduli space of 3-manifolds that comes from parameterization by the cotangent bundle of Teichm\"uller space is the same as the 3-dimensional gravity one.Comment: 53 pages, no figure. v2: typos corrected and refs adde

    Distributed utterances

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    I propose an apparatus for handling intrasentential change in context. The standard approach has problems with sentences with multiple occurrences of the same demonstrative or indexical. My proposal involves the idea that contexts can be complex. Complex contexts are built out of (“simple”) Kaplanian contexts by ordered n-tupling. With these we can revise the clauses of Kaplan’s Logic of Demonstratives so that each part of a sentence is taken in a different component of a complex context. I consider other applications of the framework: to agentially distributed utterances (ones made partly by one speaker and partly by another); to an account of scare-quoting; and to an account of a binding-like phenomenon that avoids what Kit Fine calls “the antinomy of the variable.

    Refusing to Endorse. A must Explanation for Pejoratives.

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    In her analysis of pejoratives, Eva Picardi rejects a too sharp separation between descriptive and expressive content. I reconstruct some of her arguments, endorsing Eva’s criticism of Williamson’s analysis of Dummett and developing a suggestion by Manuel Garcia Carpintero on a speech act analysis of pejoratives. Eva’s main concern is accounting for our instinctive refusal to endorse an assertion containing pejoratives because it suggests a picture of reality we do not share. Her stance might be further developed claiming that uses of pejoratives not only suggest, but also promote a wrong picture of reality. Our refusal to endorse implies rejecting not only a wrong picture of reality but also a call for participation to what that picture promotes

    Non-fermi-liquid single particle lineshape of the quasi-one-dimensional non-CDW metal Li_{0.9}Mo_{6}O_{17} : comparison to the Luttinger liquid

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    We report the detailed non-Fermi liquid (NFL) lineshape of the dispersing excitation which defines the Fermi surface (FS) for quasi-one-dimensional Li_{0.9}Mo_{6}O_{17}. The properties of Li_{0.9}Mo_{6}O_{17} strongly suggest that the NFL behavior has a purely electronic origin. Relative to the theoretical Luttinger liquid lineshape, we identify significant similarities, but also important differences.Comment: 5 pages, 3 eps figure

    Coherent amplitudon generation in K_0.3MoO_3 through ultrafast inter-band quasi particle decay

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    The charge density wave system K_0.3MoO_3 has been studied using variable energy pump-probe spectroscopy, ellipsometry, and inelastic light scattering. The observed transient reflectivity response exhibits quite a complex behavior, containing contributions due to quasi particle excitations, coherent amplitudons and phonons, and heating effects. The generation of coherent amplitudons is discussed in terms of relaxation of photo-excited quasi particles, and is found to be resonant with the interband plasmon frequency. Two additional coherent excitations observed in the transients are assigned to zone-folding modes of the charge density wave state

    Minimizing complications during retropubic radical prostatectomy - is ureteral stenting necessary?

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    <p>Abstract</p> <p>Objectives and aims</p> <p>To avoid damage to the ureters during bladder neck preparation in radical prostatectomy for prostate cancer, it may be helpful to insert ureteral stents temporarily or to intravenously administer indigo carmine dye for enhanced visualisation of ureteric orifices. We evaluated our bladder neck preserving technique at radical prostatectomy with regard to ureteric injuries.</p> <p>Patients and methods</p> <p>We analysed 369 consecutive radical prostatectomies operated in our clinic in a bladder neck preserving technique. The following parameters were assessed in this retrospective study: number of prophylactic ureteric stent insertions, application of indigo carmine dye, observed injuries of the ureters by the surgeon, postoperative increase of serum creatinine and postoperative status of kidney ultrasound.</p> <p>Results</p> <p>In 7/369 prostatectomies (1.90%) a ureteric stent insertion was performed, indigo carmine was not applied to any patient at all, yet no intraoperative injury of a ureter was observed by a surgeon. No revision was necessary due to a ureteral injury within the observation period of one year after surgery. In 17 patients with preoperative normal creatinine value a pathological value was observed on the first postoperative day (mean 1.4 mg/dl). In these patients no consecutive postrenal acute renal failure was observed, no hydronephrosis was monitored by ultrasound and no further intervention was necessary.</p> <p>Conclusions</p> <p>Bladder neck preserving operation technique does not implicate the need of prophylactic ureteric stent insertions and has no higher incidence of ureteric injuries.</p

    Monsters in Kaplan’s Logic of Demonstratives

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    Kaplan (1989a) insists that natural languages do not contain displacing devices that operate on character-such displacing devices are called monsters. This thesis has recently faced various empirical challenges (e.g., Schlenker 2003; Anand and Nevins 200
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