289,894 research outputs found

    Hare-lip surgery in the history of traditional Chinese medicine

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    There have been a few articles published in Chinese and English on hare-lip surgery in the history of traditional Chinese medicine. They are brief and some of them are inaccurate, although two recent English articles on this subject have presented an adequate picture on some aspects.' This article offers unreported information and evidence of both congenital and traumatic hare-lip surgery in the history of traditional Chinese medicine and also clarifies and corrects some of the facts and mistakes that have appeared in works previously published either in Chinese or English

    Influence of Overdrying on Dimensional Stability and Certain Strength Properties of Paper

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    In the past, the consequences of overdrying have been examined with the drying theory. This study was designed to look at the effects of overdrying on handsheets. Comparison of the dimensional change and strength properties was made between two sets of handsheets, one conditioned in the humidity room and the other overdried at 90°C for four hours. The handsheets used in this experiment were made from five types of furnishes: Hardwood Kraft, Softwood Kraft, Hardwood Kraft and Softwood Kraft combination, and two different percentages of TiO2 added to Softwood Kraft. The dimensional stability was measured by the Neenah Expansimeter. The Tappi Standard Testing Procedures were used to test the physical properties to the handsheets. The results of this study showed that overdrying improved the dimensional stability and tensile strength, yet reduced a certain amount of mullen, tear and fold in handsheets

    Comment on ``Signal of Quark Deconfinement in the Timing Structure of Pulsar Spin-Down''

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    This is a comment on a paper by Glendenning, Pei, and Weber (Phys. Rev. Lett., 79, 1603, 1997), where the authors gave an incorrect estimate of the event rate and neglected the important gravitational energy release. Previous work on the same subject is reviewed, and a new suggestion is made to link quark-hadron phase transitions with soft gamma-ray repeaters.Comment: 4 pages; to appear in Phys. Rev. Let

    Triplicity of Quarks and Leptons

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    Quarks come in three colors and have electric charges in multiples of one-third. There are also three families of quarks and leptons. Whereas the first two properties can be understood in terms of unification symmetries such as SU(5), SO(10), or E_6, why there should only be three families remains a mystery. I propose how all three properties involving the number three are connected in a fivefold application of the gauge symmetry SU(3).Comment: 10 pages, including 2 figure

    A Bi-Hamiltonian Formulation for Triangular Systems by Perturbations

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    A bi-Hamiltonian formulation is proposed for triangular systems resulted by perturbations around solutions, from which infinitely many symmetries and conserved functionals of triangular systems can be explicitly constructed, provided that one operator of the Hamiltonian pair is invertible. Through our formulation, four examples of triangular systems are exhibited, which also show that bi-Hamiltonian systems in both lower dimensions and higher dimensions are many and varied. Two of four examples give local 2+1 dimensional bi-Hamiltonian systems and illustrate that multi-scale perturbations can lead to higher-dimensional bi-Hamiltonian systems.Comment: 16 pages, to appear in J. Math. Phy

    Form Invariance of the Neutrino Mass Matrix

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    Consider the most general 3×33 \times 3 Majorana neutrino mass matrix M\cal M. Motivated by present neutrino-oscillation data, much theoretical effort is directed at reducing it to a specific texture in terms of a small number of parameters. This procedure is often {\it ad hoc}. I propose instead that for any M\cal M one may choose, it should satisfy the condition UMUT=MU {\cal M} U^T = {\cal M}, where U≠1U \neq 1 is a specific unitary matrix such that UNU^N represents a well-defined discrete symmetry in the νe,μ,τ\nu_{e,\mu,\tau} basis, NN being a particular integer not necessarily equal to one. I illustrate this idea with a number of examples, including the realistic case of an inverted hierarchy of neutrino masses.Comment: Version to appear in PR

    The Steady-State Response of a Class of Dynamical Systems to Stochastic Excitation

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    In this paper a class of coupled nonlinear dynamical systems subjected to stochastic excitation is considered. It is shown how the exact steady-state probability density function for this class of systems can be constructed. The result is then applied to some classical oscillator problems

    Deformations of Closed Strings and Topological Open Membranes

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    We study deformations of topological closed strings. A well-known example is the perturbation of a topological closed string by itself, where the associative OPE product is deformed, and which is governed by the WDVV equations. Our main interest will be closed strings that arise as the boundary theory for topological open membranes, where the boundary string is deformed by the bulk membrane operators. The main example is the topological open membrane theory with a nonzero 3-form field in the bulk. In this case the Lie bracket of the current algebra is deformed, leading in general to a correction of the Jacobi identity. We identify these deformations in terms of deformation theory. To this end we describe the deformation of the algebraic structure of the closed string, given by the BRST operator, the associative product and the Lie bracket. Quite remarkably, we find that there are three classes of deformations for the closed string, two of which are exemplified by the WDVV theory and the topological open membrane. The third class remains largely mysterious, as we have no explicit example.Comment: 50 pages, LaTeX; V2: minor changes, 2 references added, V3: typos corrected, signs added, modified discussion on higher correlator

    Calcified amorphous tumor: A rare cause of central retinal artery occlusion.

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    PurposeWe report the case of a central retinal artery occlusion secondary to presumed embolus from a calcified amorphous tumor of the heart, a very rare non-neoplastic cardiac mass.ObservationsA 60-year-old female presented with acute unilateral vision loss of the left eye. Examination revealed hand motion visual acuity of the left eye and a left relative afferent pupillary defect. Fundoscopy showed whitening of the macula with a cherry red spot, consistent with a central retinal artery occlusion. Initial workup was unremarkable, including hypercoagulability labs, magnetic resonance imaging of the brain, and magnetic resonance angiography of the head and neck. Transthoracic echocardiogram (TTE) showed calcification of the mitral valve but no masses. Subsequently, transesophageal echocardiogram (TEE) was performed, which revealed a mobile calcified amorphous tumor of the heart.ConclusionsCalcified amorphous tumor of the heart is a very rare cardiac mass that may cause retinal artery occlusion. TEE is a more sensitive imaging modality to assess for potential cardio-embolic sources if TTE is unrevealing
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