1,374 research outputs found
Kanamycin resistance during in vitro development of pollen from transgenic tomato plants
Effects of kanamycin on pollen germination and tube growth of pollen from non-transformed plants and from transgenic tomato plants containing a chimaeric kanamycin resistance gene were determined. Germination of pollen was not affected by the addition of kanamycin to the medium in both genotypes. Kanamycin, however, severely affected tube growth of pollen from non-transformed plants, while pollen from plants containing the chimaeric gene were less sensitive and produced significantly longer tubes at kanamycin concentrations between 200-400 mg l-1. Apparently, this resistance for kanamycin correlates with the expression of the chimaeric gene during male gametophytic development.
Restricted locality of quark-hadron duality in exclusive meson photoproduction reactions above the resonance region
We show how deviations from the dimensional scaling laws for exclusive
processes may be related to a breakdown in the locality of quark-hadron
duality, i.e. the "restricted locality". For exclusive reactions like meson
photo- and electroproduction above the resonance region, we explore the effects
arising from such a local duality breaking and propose that it can be a
possible source for oscillations about the smooth quark counting rule predicted
by pQCD in the 90-degree differential cross sections.Comment: Contribution to the 10th International Symposium on Meson-Nucleon
Physics and the Structure of the Nucleon (MENU2004), Beijing, 2004; presented
by Q
Reaction ⁶Li(p, Δ⁺⁺)⁶He At 1.04 GeV And The Δ−N Interaction
The reaction ⁶Li(p, Δ⁺⁺)⁶He has been studied at 1.04 GeV for transferred momenta ranging from 0.11 to 0.35 (GeV/c)2. An exponential decrease of the cross section is observed. A Glauber-type calculation is presented. The possibility of extracting information on σ(ΔN) and α(ΔN) is discussed
Pion photoproduction on the nucleon
The and reactions are essential
probes of the transition from meson-nucleon degrees of freedom to quark-gluon
degrees of freedom in exclusive processes. The cross sections of these
processes are also advantageous, for the investigation of oscillatory behavior
around the quark counting prediction, since they decrease relatively slower
with energy compared with other photon-induced processes. In this talk, we
discuss recent results on the and processes from Jefferson Lab experiment E94-104. We also discuss a
new experiment in which singles measurement from
hydrogen, and coincidence measurements at the
quasifree kinematics from deuterium for center-of-mass energies between 2.3 GeV
to 3.4 GeV in fine steps at a center-of-mass angle of are planned.
The proposed measurement will allow a detailed investigation of the oscillatory
scaling behavior in photopion production processes.Comment: 6 pages, 5 figures, Plenary talk presented at the HiX2004 Workshop,
July 26-28, Marseille, France. References adde
Higher and missing resonances in omega photoproduction
We study the role of the nucleon resonances () in
photoproduction by using the quark model resonance parameters predicted by
Capstick and Roberts. The employed and
amplitudes include the configuration mixing effects due to the residual
quark-quark interactions. The contributions from the nucleon resonances are
found to be important in the differential cross sections at large scattering
angles and various spin observables. In particular, the parity asymmetry and
beam-target double asymmetry at forward scattering angles are suggested for a
crucial test of our predictions. The dominant contributions are found to be
from , a missing resonance, and which is
identified as the of the Particle Data Group.Comment: 8 pages, LaTeX with ws-p8-50x6-00.cls, 4 figures (5 eps files), Talk
presented at the NSTAR2001 Workshop on the Physics of Excited Nucleons,
Mainz, Germany, Mar. 7-10, 200
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