64,298 research outputs found
In vivo measurement of mechanical impedance of bone
System of measurement provides indications of ulnar properties independent of characteristics of surrounding soft tissue and other bones. Mechanical modal approximated ulnar response so average bending rigidity could be determined to provide direct index of bone resistance to bending loading
Country of Origin Advertising and U.S. Wine Imports
The objective of this paper is to investigate the impact of media advertising on the US consumption of imported wine. A panel data of seven countries and twelve years from 1994-2005 is used to estimate the demand function for US wine imports. Our empirical analysis reveals evidence of strong price and advertising effects of domestic and imported wines on imported quantities; the advertising of imported wines significantly increases the quantity of imports while the advertising of domestic wines has a strong depressing effect on imported wine volumes. Our short-run import demand price and advertising elasticity estimates are -0.406 and 0.109 for imports and 0.654 and -0.370 for domestic wines, respectively. Other determinants such as population, real income and country specific fixed effects are also found significant. Based on our model estimates, we compute the marginal return to advertising to be 3.40 for the U.S.International Relations/Trade, Marketing,
Nonparametric maximum likelihood estimation of probability densities by penalty function methods
When it is known a priori exactly to which finite dimensional manifold the probability density function gives rise to a set of samples, the parametric maximum likelihood estimation procedure leads to poor estimates and is unstable; while the nonparametric maximum likelihood procedure is undefined. A very general theory of maximum penalized likelihood estimation which should avoid many of these difficulties is presented. It is demonstrated that each reproducing kernel Hilbert space leads, in a very natural way, to a maximum penalized likelihood estimator and that a well-known class of reproducing kernel Hilbert spaces gives polynomial splines as the nonparametric maximum penalized likelihood estimates
Determination of mechanical properties of excised dog radii from lateral vibration experiments
Experimental data which can be used as a guideline in developing a mathematical model for lateral vibrations of whole bone are reported. The study used wet and dry dog radii mounted in a cantilever configuration. Data are also given on the mechanical, geometric, and viscoelastic properties of bones
Chemical propulsion research at MSFC
Chemical propulsion research reviews at Marshall Space Flight Cente
Laser cooling in the Penning trap: an analytical model for cooling rates in the presence of an axializing field
Ions stored in Penning traps may have useful applications in the field of
quantum information processing. There are, however, difficulties associated
with the laser cooling of one of the radial motions of ions in these traps,
namely the magnetron motion. The application of a small radio-frequency
quadrupolar electric potential resonant with the sum of the two radial motional
frequencies has been shown to couple these motions and to lead to more
efficient laser cooling. We present an analytical model that enables us to
determine laser cooling rates in the presence of such an 'axializing' field. It
is found that this field leads to an averaging of the laser cooling rates for
the two motions and hence improves the overall laser cooling efficiency. The
model also predicts shifts in the motional frequencies due to the axializing
field that are in qualitative agreement with those measured in recent
experiments. It is possible to determine laser cooling rates experimentally by
studying the phase response of the cooled ions to a near resonant excitation
field. Using the model developed in this paper, we study the expected phase
response when an axializing field is present.Comment: 22 pages, 7 figure
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