681 research outputs found

    On kernel polynomials and self perturbation of orthogonal polynomials

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    20 pages, no figures.-- MSC2000 code: 42C05.MR#: MR1847402 (2002h:42049)Zbl#: Zbl 1034.42022Given an orthogonal polynomial system (Qn(x))n=0infty(Q_n(x))_{n=0} infty, define another polynomial system by where αn are complex numbers and t is a positive integer. We find conditions for (Pn(x))n=0infty(P_n(x))_{n=0} infty to be an orthogonal polynomial system. When t=1 and α1≠0, it turns out that (Qn(x))n=0infty(Q_n(x))_{n=0} infty must be kernel polynomials for (Pn(x))n=0infty(P_n(x))_{n=0} infty for which we study, in detail, the location of zeros and semi-classical character.The first author (KHK) was partially supported by the BK-21 project and KOSEF(98-0701-03-01-5). The second author (DWL) was partially supported by BK-21 project. The third author (FM) was partially supported by Dirección General de Enseñanza Superior (DGES) of Spain under grant PB96-0120-C03-01. The fourth author (SBP) was partially supported by the Hwarangdae Research Institute.Publicad

    Compatible pairs of orthogonal polynomials

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    19 pages, no figures.-- MSC1991 code: 33C45.MR#: MR1736624 (2001a:33009)Zbl#: Zbl 0944.33012We find necessary and sufficient conditions for an orthogonal polynomial system to be compatible with another orthogonal polynomial system. As applications, we find new characterizations of semi-classical and classical orthogonal polynomials.The work of D. H. Kim and K. H. Kwon was partially supported by KOSEF (98-0701-03-01-5) and GARC at Seoul National University. The work of F. Marcellán was partially supported by Dirección General de Enseñanza Superior (DGES) of Spain under grant PB96-0120-C03-0l.Publicad

    A Note on Tachyons in the D3+D3ˉD3+{\bar {D3}} System

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    The periodic bounce of Born-Infeld theory of D3D3-branes is derived, and the BPS limit of infinite period is discussed as an example of tachyon condensation. The explicit bounce solution to the Born--Infeld action is interpreted as an unstable fundamental string stretched between the brane and its antibrane.Comment: 10 pages, 2 figures. v2: minor changes, acknowledgement added; v3: explanations and references added. Final version to appear in Mod. Phys. Lett.

    Duality Symmetry in Momentum Frame

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    Siegel's action is generalized to the D=2(p+1) (p even) dimensional space-time. The investigation of self-duality of chiral p-forms is extended to the momentum frame, using Siegel's action of chiral bosons in two space-time dimensions and its generalization in higher dimensions as examples. The whole procedure of investigation is realized in the momentum space which relates to the configuration space through the Fourier transformation of fields. These actions correspond to non-local Lagrangians in the momentum frame. The self-duality of them with respect to dualization of chiral fields is uncovered. The relationship between two self-dual tensors in momentum space, whose similar form appears in configuration space, plays an important role in the calculation, that is, its application realizes solving algebraically an integral equation.Comment: 11 pages, no figures, to appear in Phys. Rev.

    Cellular requirements for antigen processing by antigen-presenting cells: Evidence for different pathways in forming the same antigenic determinants

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    In this report we examined the antigen-presenting cell (APC) requirements for activation of T-cell hybridomas specific for the protein antigen PPD (purified protein derivative of tuberculin). During the course of these studies we observed that glutaraldehyde fixation of Ia-positive A20.2JAD (A20) and P388D1 stimulator cells had different effects on T-cell activation. A20 cells fixed with glutaraldehyde stimulated the T cells in the presence of PPD as efficiently as nonfixed A20 cells. By contrast, glutaraldehyde treatment of Ia-positive P388D1 cells dramatically inhibited their ability to process and/or present PPD to T cells. This was not due to nonspecific effects on the P388D1 cells since cells prepulsed with PPD prior to glutaraldehyde treatment stimulated T cells as efficiently as non-glutaraldehyde-treated P388D1 cells. In addition, there was no apparent difference in "fixing" of the two cell types as determined by the uptake of radiolabeled thymidine. These observations suggested that P388D1, but not A20, cells required PPD internalization to form the relevant antigenic determinants. This was substantiated by showing that treatment of P388D1 cells with chloroquine prior to PPD pulsing eliminated their stimulatory capacity, but had no effect on P388D1 cells previously pulsed with PPD. Chloroquine treatment had no effect on stimulation by A20 cells. Since PPD internalization appeared not to be required for presentation by A20 cells, we next determined if isolated A20 plasma membranes would substitute for the intact cell. We observed that the isolated plasma membranes from PPD-pulsed A20 cells stimulated the T hybridoma cells, and that this stimulation was antigen-specific and was inhibited by anti-Ia monoclonal antibodies. Taken together, the results presented here suggest that for the PPD-specific T-cell responses examined here, different APC utilize distinct pathways to present the same antigenic determinant for T-cell recognition.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25474/1/0000014.pd

    Prediction on lengths of stay in the postanesthesia care unit following general anesthesia: preliminary study of the neural network and logistic regression modelling.

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    The length of stay in the postanesthesia care unit (PACU) following general anesthesia in adults is an important issue. A model, which can predict the results of PACU stays, could improve the utilization of PACU and operating room resources through a more efficient arrangement. The purpose of study was to compare the performance of neural network to logistic regression analysis using clinical sets of data from adult patients undergoing general anesthesia. An artificial neural network was trained with 409 clinical sets using backward error propagation and validated through independent testing of 183 records. Twenty-two inputs were used to find determinants and to predict categorical values. Logistic regression analysis was performed to provide a comparison. The neural network correctly predicted in 81.4% of situations and identified discriminating variables (intubated state, sex, neuromuscular blocker and intraoperative use of opioid), whereas the figure was 65.0% in logistic regression analysis. We concluded that the neural network could provide a useful predictive model for the optimization of limited resources. The neural network is a new alternative classifying method for developing a predictive paradigm, and it has a higher classifying performance compared to the logistic regression model

    KMT-2016-BLG-1107: A New Hollywood-Planet Close/Wide Degeneracy

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    We show that microlensing event KMT-2016-BLG-1107 displays a new type of degeneracy between wide-binary and close-binary Hollywood events in which a giant-star source envelops the planetary caustic. The planetary anomaly takes the form of a smooth, two-day "bump" far out on the falling wing of the light curve, which can be interpreted either as the source completely enveloping a minor-image caustic due to a close companion with mass ratio q=0.036q=0.036, or partially enveloping a major-image caustic due to a wide companion with q=0.004q=0.004. The best estimates of the companion masses are both in the planetary regime (3.31.8+3.5Mjup3.3^{+3.5}_{-1.8}\,M_{\rm jup} and 0.0900.037+0.096Mjup0.090^{+0.096}_{-0.037}\,M_{\rm jup}) but differ by an even larger factor than the mass ratios due to different inferred host masses. We show that the two solutions can be distinguished by high-resolution imaging at first light on next-generation ("30m") telescopes. We provide analytic guidance to understand the conditions under which this new type of degeneracy can appear.Comment: 23 pages, 7 figures, accepted for publication in A

    KMT-2018-BLG-1990Lb: A Nearby Jovian Planet From A Low-Cadence Microlensing Field

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    We report the discovery and characterization of KMT-2018-BLG-1990Lb, a Jovian planet (mp=0.570.25+0.79MJ)(m_p=0.57_{-0.25}^{+0.79}\,M_J) orbiting a late M dwarf (M=0.140.06+0.20M)(M=0.14_{-0.06}^{+0.20}\,M_\odot), at a distance (D_L=1.23_{-0.43}^{+1.06}\,\kpc), and projected at 2.6±0.62.6\pm 0.6 times the snow line distance, i.e., a_{\rm snow}\equiv 2.7\,\au (M/M_\odot), This is the second Jovian planet discovered by KMTNet in its low cadence (0.4hr10.4\,{\rm hr}^{-1}) fields, demonstrating that this population will be well characterized based on survey-only microlensing data.Comment: 24 pages, 7 figures, 4 table
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