2,018 research outputs found
Comments on the Relativity of Shape
In this talk I address three topics related to the shape of hadrons:
1. The Lorentz contraction of bound states. Few dedicated studies of this
exist - I describe a recent calculation for ordinary atoms (positronium).
2. Does the A-dependence of nuclear structure functions indicate a change of
proton shape in the nuclear environment? (My short answer is no.)
3. The size of Fock states contributing to processes involving large momentum
transfers. End-point configurations can be transversally extended and yet
sufficiently short-lived to contribute coherently to hard scattering.Comment: Talk at the Workshop on the Shape of Hadrons, 27-29 April 2006 in
Athens, Greece. 11 pages, 15 figure
Raman detection of macular carotenoid pigments in intact human retina
Journal ArticlePURPOSE: To develop and test a novel noninvasive optical technique suitable for the objective measurement of macular carotenoid levels in human retina. METHODS: A resonance Raman scattering apparatus was constructed to measure carotenoid levels in flat-mounted human retinas and eyecups and in experimental animal eyes. Light from an argon laser was used to resonantly excite the electronic absorption of the carotenoid pigments, and scattered light was collected and analyzed by a Raman spectrometer. After carotenoid Raman measurements were completed on the retinal samples, macular carotenoid levels were determined by high-performance liquid chromatography (HPLC). RESULTS: Carotenoid resonance Raman scattering proved to be a highly sensitive and specific method for the noninvasive measurement of macular pigments in the human retina. Signal strength scaled linearly with actual macular carotenoid content as measured by HPLC. Our apparatus was also used to record resonance Raman signals from xanthophyll carotenoids stored in the retinal pigment epithelium of intact frog eyes. CONCLUSIONS: This new noninvasive optical method will facilitate studies of ocular carotenoid distributions and their role in degenerative diseases of the eye and may allow for the rapid screening of carotenoid levels in large populations at risk for vision loss from age-related macular degeneration, the leading cause of blindness in the elderly in the United States. A prototype clinical instrument is under development
Resonances in rotationally inelastic scattering of OH() with helium and neon
We present detailed calculations on resonances in rotationally and spin-orbit
inelastic scattering of OH (X\,^2\Pi, j=3/2, F_1, f) radicals with He and Ne
atoms. We calculate new \emph{ab initio} potential energy surfaces for OH-He,
and the cross sections derived from these surfaces compare favorably with the
recent crossed beam scattering experiment of Kirste \emph{et al.} [Phys. Rev. A
\textbf{82}, 042717 (2010)]. We identify both shape and Feshbach resonances in
the integral and differential state-to-state scattering cross sections, and we
discuss the prospects for experimentally observing scattering resonances using
Stark decelerated beams of OH radicals.Comment: 14 pages, 15 Figure
Improving Heart Failure Self-Management Support by Actively Engaging Out-of-Home Caregivers: Results of a Feasibility Study
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72336/1/j.1751-7133.2008.07474.x.pd
Event Horizons in Numerical Relativity II: Analyzing the Horizon
We present techniques and methods for analyzing the dynamics of event
horizons in numerically constructed spacetimes. There are three classes of
analytical tools we have investigated. The first class consists of proper
geometrical measures of the horizon which allow us comparison with perturbation
theory and powerful global theorems. The second class involves the location and
study of horizon generators. The third class includes the induced horizon
2-metric in the generator comoving coordinates and a set of membrane-paradigm
like quantities. Applications to several distorted, rotating, and colliding
black hole spacetimes are provided as examples of these techniques.Comment: 23 double column pages including 28 figures. Higher quality figures
(big size!) available upon request (jmasso OR [email protected]
Recent Developments in Precision Electroweak Physics
Developments in precision electroweak physics in the two years since the
symposium are briefly summarized.Comment: Update on recent developments, prepared for the publication of the
Proceedings of Alberto Sirlin Symposium, New York University, October 2000.
10 pages, 1 figur
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