Showing 5531 - 5540 of 5713 Items

Measurement of the B̄→D*lν̄ branching fractions and -Vcb-

Date: 1995-01-01

Creator: B. Barish, M. Chadha, S. Chan, D. F. Cowen, G., Eigen, J. S. Miller, C. O'Grady, J. Urheim, A. J. Weinstein, D. Acosta, M. Athanas, G. Masek, H. P. Paar, J. Gronberg, R. Kutschke, S. Menary, R. J. Morrison, S. Nakanishi, H. N. Nelson, T. K. Nelson, C. Qiao, J. D. Richman, A. Ryd, H. Tajima, D. Sperka, M. S. Witherell, M. Procario, R. Balest, K. Cho, M. Daoudi, W. T. Ford

Access: Open access

We study the exclusive semileptonic B meson decays B-→D*0l-ν̄ and B̄0→D*+l-ν̄ using data collected with the CLEO II detector at the Cornell Electron-positron Storage Ring (CESR). We present measurements of the branching fractions scrB(B̄0→D*+l-ν̄)= (0.5/f00)[4.49±0.32(stat.)±0.39 (syst.)]% and scrB(B-→D*0l-(ν̄)= (0.5/f+-)[5.13±0.54 (stat) ±0.64 (syst)]%, where f00 and f+- are the neutral and charged B meson production fractions at the Υ(4S) resonance, respectively. Assuming isospin invariance and taking the ratio of charged to neutral B meson lifetimes measured at higher energy machines, we determine the ratio f+-/f00=1.04±0.13 (stat) ±0.12 (syst) ±0.10 (lifetime); further assuming f+-+f00=1 we also determine the partial width Γ(B̄→D*lν̄)=[29.9±1.9 (stat) ±2.7 (syst.) ±2.0 (lifetime)] ns-1 (independent of f+-/f00). From this partial width we calculate B̄→D*lν̄ branching fractions that do not depend on f+-/f00 or the individual B lifetimes, but only on the charged to neutral B lifetime ratio. The product of the CKM matrix element -Vcb- times the normalization of the decay form factor at the point of no recoil of the D* meson, scrF(y=1), is determined from a linear fit to the combined differential decay rate of the exclusive B̄→D*lν̄ decays: -Vcb-scrF(1)=0.0351±0.0019 (stat) ±0.0018 (syst) ±0.0008 (lifetime). The value for -Vcb- is extracted using theoretical calculations of the form factor normalization. © 1995 The American Physical Society.


Report of the President, Bowdoin College 1961-1962

Date: 1962-01-01

Access: Open access



The twin spot generator for differential Drosophila lineage analysis

Date: 2009-07-28

Creator: Ruth Griffin, Anne Sustar, Marianne Bonvin, Richard Binari, Alberto, del Valle Rodriguez, Amber M. Hohl, Jack R. Bateman, Christians Villalta, Elleard Heffern, Didier Grunwald, Chris Bakal, Claude Desplan, Gerold Schubiger, C. Ting Wu, Norbert Perrimon

Access: Open access

In Drosophila melanogaster, widely used mitotic recombination-based strategies generate mosaic flies with positive readout for only one daughter cell after division. To differentially label both daughter cells, we developed the twin spot generator (TSG) technique, which through mitotic recombination generates green and red twin spots that are detectable after the first cell division as single cells. We propose wide applications of TSG to lineage and genetic mosaic studies.


Bowdoin College Catalogue (1830 Apr)

Date: 1830-04-01

Access: Open access



The tyrosine kinase Abl and its substrate enabled collaborate with the receptor phosphatase Dlar to control motor axon guidance

Date: 1999-01-01

Creator: Zachary Wills, Jack Bateman, Christopher A. Korey, Allen Comer, David, Van Vactor

Access: Open access

Genetic analysis of growth cone guidance choice points in Drosophila identified neuronal receptor protein tyrosine phosphatases (RPTPs) as key determinants of axon pathfinding behavior. We now demonstrate that the Drosophila Abl tyrosine kinase functions in the intersegmental nerve b (ISNb) motor choice point pathway as an antagonist of the RPTP Dlar. The function of Abl in this pathway is dependent on an intact catalytic domain. We also show that the Abl phosphoprotein substrate Enabled (Ena) is required for choice point navigation. Both Abl and Ena proteins associate with the Dlar cytoplasmic domain and serve as substrates for Dlar in vitro, suggesting that they play a direct role in the Dlar pathway. These data suggest that Dlar, Abl, and Ena define a phosphorylation state-dependent switch that controls growth cone behavior by transmitting signals at the cell surface to the actin cytoskeleton.


Bowdoin College Catalogue (1924-1925)

Date: 1925-01-01

Access: Open access

Bowdoin College Bulletin no. 137


Report of the President, Bowdoin College 1967-1968

Date: 1968-01-01

Access: Open access



Partitioning of the global fossil CO2 sink using a 19-year trend in atmospheric O2

Date: 1999-07-01

Creator: R. L. Langenfelds, R. J. Francey, L. P. Steele, M. Battle, R. F., Keeling, W. F. Budd

Access: Open access

O2/N2 is measured in the Cape Grim Air Archive (CGAA), a suite of tanks filled with background air at Cape Grim, Tasmania (40.7°S, 144.8°E) between April 1978 and January 1997. Derived trends are compared with published O2/N2 records and assessed against limits on interannual variability of net terrestrial exchanges imposed by trends of δ13C in CO2. Two old samples from 1978 and 1987 and eight from 1996/97 survive critical selection criteria and give a mean 19-year trend in δ(O2/N2) of -16.7 ± 0.5 per meg yr-1, implying net storage of +2.3 ± 0.7 GtC (1015 g carbon) yr-1 of fossil fuel CO2 in the oceans and +0.2 ± 0.9 GtC yr-1 in the terrestrial biosphere. The uptake terms are consistent for both O2/N2 and δ13C tracers if the mean 13C isotopic disequilibrium flux, combining terrestrial and oceanic contributions, is 93 ± 15 GtC ‰ yr-1. Copyright 1999 by the American Geophysical Union.


Report of the President, Bowdoin College 1965-1966

Date: 1966-01-01

Access: Open access



Bowdoin College - Medical School of Maine Catalogue (1916-1917)

Date: 1918-01-01

Access: Open access

Bowdoin College Bulletin no. 68