Showing 641 - 650 of 733 Items
Date: 1993-01-01
Creator: M. Procario, S. Yang, R. Balest, K. Cho, M., Daoudi, W. T. Ford, D. R. Johnson, K. Lingel, M. Lohner, P. Rankin, J. G. Smith, J. P. Alexander, C. Bebek, K. Berkelman, D. Besson, T. E. Browder, D. G. Cassel, H. A. Cho, D. M. Coffman, P. S. Drell, R. Ehrlich, R. S. Galik, M. Garcia-Sciveres, B. Geiser, B. Gittelman, S. W. Gray, D. L. Hartill, B. K. Heltsley, K. Honscheid, C. D. Jones, S. L. Jones
Access: Open access
- With the CLEO-II detector at the Cornell Electron Storage Ring, we have measured branching fractions for tau lepton decay into one-prong final states with multiple π0's Bhnπ0, normalized to the branching fraction for tau decay into one charged particle and a single π0. We find Bh2π0/Bhπ0=0. 345±0.006±0.016, Bh3π0/Bhπ0=0.041 ±0.003±0. 005, and Bh4π0/Bhπ0=0.006±0.002±0.002. © 1993 The American Physical Society.
Date: 1991-01-01
Creator: K. Kinoshita, F. M. Pipkin, M. Procario, Richard Wilson, J., Wolinski, D. Xiao, Y. Zhu, R. Ammar, P. Baringer, D. Coppage, R. Davis, P. Haas, M. Kelly, N. Kwak, Ha Lam, S. Ro, Y. Kubota, J. K. Nelson, D. Perticone, R. Poling, S. Schrenk, G. Crawford, R. Fulton, T. Jensen, D. R. Johnson, H. Kagan, R. Kass, R. Malchow, F. Morrow, J. Whitmore, P. Wilson
Access: Open access
- We have made measurements of decay modes of neutral D mesons into exclusive final states containing photons using data collected with the CLEO detector at the Cornell Electron Storage Ring. We report observation of D0'K-+-+0 (charge conjugates are implicit), and present new measurements of the branching ratios for D0'K-+0, D0'K0+0-, D0'K00, K*0, and D0'K0. Where possible, results are compared with theoretical predictions for two-body D0 decays. © 1991 The American Physical Society.
Date: 1991-01-01
Creator: R. Fulton, T. Jensen, D. R. Johnson, H. Kagan, R., Kass, F. Morrow, J. Whitmore, P. Wilson, D. Bortoletto, W. Y. Chen, J. Dominick, R. L. McIlwain, D. H. Miller, C. R. Ng, S. F. Schaffner, E. I. Shibata, I. P.J. Shipsey, W. M. Yao, M. Battle, K. Sparks, E. H. Thorndike, C. H. Wang, M. S. Alam, I. J. Kim, W. C. Li, V. Romero, C. R. Sun, P. N. Wang, M. M. Zoeller, M. Goldberg, T. Haupt
Access: Open access
- We report new measurements of the branching fractions B. Combining these results with our previous measurement of BD*+l we find that the ratio of semileptonic widths for final states with a vector meson and pseudoscalar meson is (2.6-0.6-0.8+1.1+1.0) and the ratio of charged- to neutral-B-meson lifetimes is (0.89±0.19±0.13)(f00f+-) where (f00f+-) is the ratio of neutral- to charged-B-meson production at the branching fraction, we calculate |Vcb|=0.040±0.006±0.006, where the first error is statistical and the second is systematic and dominated by the uncertainty in the B-meson lifetime. © 1991 The American Physical Society.
Date: 1991-01-01
Creator: R. Ammar, P. Baringer, D. Coppage, R. Davis, P., Haas, M. Kelly, N. Kwak, H. Lam, S. Ro, Y. Kubota, J. K. Nelson, D. Perticone, R. Poling, S. Schrenk, G. Crawford, R. Fulton, T. Jensen, D. Johnson, H. Kagan, R. Kass, R. Malchow, F. Marrow, J. Whitmore, P. Wilson, D. Bortoletto, D. N. Brown, J. Dominick, R. L. McIlwain, D. H. Miller, M. Modesitt, C. R. Ng
Access: Open access
- CLEO has measured decay modes of the D0 and D+ into final states consisting of K's, s, K0's and 0's, using data taken with the CLEO detector at the Cornell Electron Storage Ring. We report new results on the decays of D0's into 4, K-K+-+, 0K+K-, 0K+-, K0K-+, 3KS0 and 0 together with some of their resonant substructure. We also present the first observation of the decay D00K+ and give limits on the doubly-Cabibbo-suppressed decays of the D0 into K+- and K+-+-. © 1991 The American Physical Society.
Date: 1982-11-11
Creator: Bruce D. Kohorn, Peter M.m. Rae
Access: Open access
- Tandem repeats of ribosomal RNA transcription units in Drosophila melanogaster are separated by a nontranscribed spacer that is comprised in part of serial repeats of a 0.24 kb sequence. DNA sequence analysis shows that such repeats are imperfect copies of a region that includes the site of in vivo rRNA transcription initiation (ca. -240 to +30). Subclones of the rDNA spacer that are copies of the sequence extending from -34 through the initiation site support detectable in vitro transcription in a mixture involving a Drosophila cell-free extract, but accurate in vitro transcription is considerably enhanced when a nontranscribed spacer template includes a copy of the sequence extending upstream of -34. From a comparison of the sequence and transcription template-effectiveness of various rDNA subclones, we infer that a major promoter of RNA polymerase I activity lies between -150 and -30 in the rDNA nontranscribed spacer. The nontranscribed spacer copies of the initiation region are less effective templates for transcription than is the region of in vivo initiation and there are differences between spacer repeates and the authentic sequence downstream of -240 that may account for this. © 1982 IRL Press Limited.
Date: 1995-06-01
Creator: F. Montes de Oca, M. L. Zeeman
Access: Open access
- We generalise and unify some recent results about extinction in nth-order nonautonomous competitive Lotka-Volterra systems. For each r ≤ n, we show that if the coefficients are continuous, bounded by strictly positive constants, and satisfy certain inequalities, then any solution with strictly positive initial values has the property that n - r of its components vanish, whilst the remaining r components asymptotically approach a canonical solution of an r-dimensional restricted system. In other words, r of the species being modeled survive whilst the remaining n - r are driven to extinction. © 1995 Academic Press, Inc.
Date: 2011-12-01
Creator: Azer Akhmedov, Melanie Stein, Jennifer Taback
Access: Open access
- We produce a sequence of markings Sk of Thompson's group F within the space Gn of all marked n-generator groups so that the sequence (F, Sk) converges to the free group on n generators, for n ≥ 3. In addition, we give presentations for the limits of some other natural (convergent) sequences of markings to consider on F within G3, including (F, {x0, x1, xn}) and (F, {x0, x1, x0n}) © 2011 Springer Science+Business Media B.V.
Date: 2005-09-22
Creator: Sean Cleary, Jennifer Taback
Access: Open access
- We explore the geometry of the Cayley graphs of the lamplighter groups and a wide range of wreath products. We show that these groups have dead end elements of arbitrary depth with respect to their natural generating sets. An element w in a group G with finite generating set X is a dead end element if no geodesic ray from the identity to w in the Cayley graph Γ(G, X) can be extended past w. Additionally, we describe some non-convex behaviour of paths between elements in these Cayley graphs and seesaw words, which are potential obstructions to these graphs satisfying the k-fellow traveller property. © The Author 2005. Published by Oxford University Press. All rights reserved.
Date: 2009-12-01
Creator: Bruce D. Kohorn, Susan Johansen, Akira Shishido, Tanya Todorova, Rhysly, Martinez, Elita Defeo, Pablo Obregon
Access: Open access
- The angiosperm extracellular matrix, or cell wall, is composed of a complex array of cellulose, hemicelluose, pectins and proteins, the modification and regulated synthesis of which are essential for cell growth and division. The wall associated kinases (WAKs) are receptor-like proteins that have an extracellular domain that bind pectins, the more flexible portion of the extracellular matrix, and are required for cell expansion as they have a role in regulating cellular solute concentrations. We show here that both recombinant WAK1 and WAK2 bind pectin in vitro. In protoplasts pectins activate, in a WAK2-dependent fashion, the transcription of vacuolar invertase, and a wak2 mutant alters the normal pectin regulation of mitogen-activated protein kinases. Microarray analysis shows that WAK2 is required for the pectin activation of numerous genes in protoplasts, many of which are involved in cell wall biogenesis. Thus, WAK2 plays a major role in signaling a diverse array of cellular events in response to pectin in the extracellular matrix. © 2009 Blackwell Publishing Ltd.
Date: 2003-02-03
Creator: Stephen G. Naculich, Howard J. Schnitzer, Niclas Wyllard
Access: Open access
- We study the pp-wave limits of various elliptic models with orientifold planes and D7-branes, as well as the pp-wave limit of an orientifold of AdS5 × T11. Many of the limits contain both open and closed strings. We also present pp-wave limits of theories which give rise to a compact null direction and contain open strings. Maps between the string theory states and gauge theory operators are proposed. © 2002 Elsevier Science B.V. All rights reserved.