4,986 research outputs found
Quantitizing findings from qualitative studies for integration in mixed studies reviewing
In mixed methods reviewing, data from quantitative and qualitative studies are combined at the review level. One possible way to combine findings of quantitative and qualitative studies is to quantitize qualitative findings prior to their incorporation in a quantitative review. There are only a few examples of the quantification of qualitative findings within this context. This study adds to current research on mixed methods review methodology by reporting the pilot implementation of a new four‐step quantitizing approach. We report how we extract and quantitize the strength of relationships found in qualitative studies by assigning correlations to vague quantifiers in text fragments. This article describes (a) how the analysis is prepared; (b) how vague quantifiers in text fragments are organized and transformed to numerical values; (c) how qualitative studies as a whole are assigned effect sizes; and (d) how the overall mean effects size and variance can be calculated. The pilot implementation shows how findings from 26 primary qualitative studies are transformed into mean effect sizes and corresponding variances
The Investigation of Space Charge Dominated Beams in a Synchrotron
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Elastic Scattering of 270 MeV 3-He Particles
This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit
The Ay Problem for p-3He Elastic Scattering
We present evidence that numerically accurate quantum calculations employing
modern internucleon forces do not reproduce the proton analyzing power, A_y,
for p-3He elastic scattering at low energies. These calculations underpredict
new measured analyzing powers by approximately 30% at E_{c.m.} = 1.20 MeV and
by 40% at E_{c.m.} = 1.69 MeV, an effect analogous to a well-known problem in
p-d and n-d scattering. The calculations are performed using the complex Kohn
variational principle and the (correlated) Hyperspherical Harmonics technique
with full treatment of the Coulomb force. The inclusion of the three-nucleon
interaction does not improve the agreement with the experimental data.Comment: Latex file, 4 pages, 2 figures, to be published on Phys. Rev. Let
Nuclear structure studies with the 7Li(e,e'p) reaction
Experimental momentum distributions for the transitions to the ground state
and first excited state of 6He have been measured via the reaction
7Li(e,e'p)6He, in the missing momentum range from -70 to 260 MeV/c. They are
compared to theoretical distributions calculated with mean-field wave functions
and with variational Monte Carlo (VMC) wave functions which include strong
state-dependent correlations in both 7Li and 6He. These VMC calculations
provide a parameter-free prediction of the momentum distribution that
reproduces the measured data, including its normalization. The deduced summed
spectroscopic factor for the two transitions is 0.58 +/- 0.05, in perfect
agreement with the VMC value of 0.60. This is the first successful comparison
of experiment and ab initio theory for spectroscopic factors in p-shell nuclei.Comment: 4 pages, 3 figure
Spin-flipping a stored polarized proton beam with an rf dipole
Frequent polarization reversals, or spin-flips, of a stored polarized high-energy beam may greatly reduce systematic errors of spin asymmetry measurements in a scattering asymmetry experiment. We studied the spin-flipping of a 120 MeV horizontally-polarized proton beam stored in the IUCF Cooler Ring by ramping an rf-dipole magnet’s frequency through an rf-induced depolarizing resonance in the presence of a nearly-full Siberian snake. After optimizing the frequency ramp parameters, we used multiple spin-flips to measure a spin-flip efficiency of 86.5±0.5%.86.5±0.5%. The spin-flip efficiency was apparently limited by the rf-dipole’s field strength. This result indicates that an efficient spin-flipping a stored polarized beam should be possible in high energy rings such as RHIC and HERA where Siberian snakes are certainly needed and only dipole rf-flipper-magnets are practical. © 2000 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87561/2/662_1.pd
Development of the Techology for Intermediate Energy Electron Cooling
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
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