363 research outputs found
Scaling law for the electromagnetic form factors of the proton
The violation of the scaling law for the electric and magnetic form factors
of the proton are examined within the cloudy bag model. The suppression of the
ratio of the electric and magnetic form factors is natural in the bag model.
The pion cloud plays a moderate role in understanding the recent data from
TJNAF.Comment: 8 pages, REVTeX, 2 figures include
High- Elastic -scattering and QCD predictions
In the framework of pertubative QCD it is argued that in the elastic
-scattering at few the light-cone-frame
helicity-flip amplitudes could not be omitted. The obtained ratio
of Rosenbluth structure functions is shown to be in a good agreement with
experimental data. The high behavior of tensor analysing power
is discussed.Comment: 6 pages + 2 ps figures not included, LaTeX, ITP-93-33
Pilot study of DNA extraction from archival unstained bone marrow slides: comparison of three rapid methods
DNA can be isolated from a variety of human sample sources including anti-coagulant whole blood, bloodstains, hairs, tissue samples and buccal epithelial cells. The purpose of this study was to compare yield and quality of DNA samples obtained with the use of three different methods. The ability of these procedures to provide DNA for polymerase chain reaction (PCR) amplification from archival unstained bone marrow slides was tested on 35 different patients’ slides. Boiling in distilled water (A), proteinase K/Tween 35 method coupled with simplified phenol/chloroform isoamyl alcohol protocol (B) and modified commercial nucleon extraction and purification protocol (C, Amersham Life Science) gave extraction efficiencies of 57, 74 and 100% respectively. Our results demonstrate that rough DNA extraction methods have decreased efficiencies compared to complete DNA extraction protocols and that the latter are required to ensure highly reproducible results from archival unstained bone marrow slides.Key words: DNA, polymerase chain reaction, bone marrow slides, reagent ki
Comparison of Relativistic Nucleon-Nucleon Interactions
We investigate the difference between those relativistic models based on
interpreting a realistic nucleon-nucleon interaction as a perturbation of the
square of a relativistic mass operator and those models that use the method of
Kamada and Gl\"ockle to construct an equivalent interaction to add to the
relativistic mass operator. Although both models reproduce the phase shifts and
binding energy of the corresponding non-relativistic model, they are not
scattering equivalent. The example of elastic electron-deuteron scattering in
the one-photon-exchange approximation is used to study the sensitivity of
three-body observables to these choices. Our conclusion is that the differences
in the predictions of the two models can be understood in terms of the
different ways in which the relativistic and non-relativistic -matrices are
related. We argue that the mass squared method is consistent with conventional
procedures used to fit the Lorentz-invariant cross section as a function of the
laboratory energy.Comment: Revtex 13 pages, 5 figures, corrected some typo
Does The 3N-Force Have A Hard Core?
The meson-nucleon dynamics that generates the hard core of the RuhrPot
two-nucleon interaction is shown to vanish in the irreducible 3N force. This
result indicates a small 3N force dominated by conventional light
meson-exchange dynamics and holds for an arbitrary meson-theoretic Lagrangian.
The resulting RuhrPot 3N force is defined in the appendix. A completely
different result is expected when the Tamm-Dancoff/Bloch-Horowitz procedure is
used to define the NN and 3N potentials. In that approach, (e.g. full Bonn
potential) both the NN {\it and} 3N potentials contain non-vanishing
contributions from the coherent sum of meson-recoil dynamics and the
possibility of a large hard core requiring explicit calculation cannot be ruled
out.Comment: 16 pages REVTeX + 3 ps fig
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