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Monotone Clutters, Guoli Ding Aug 1993

Monotone Clutters, Guoli Ding

Faculty Publications

A clutter is k-monotone, completely monotone or threshold if the corresponding Boolean function is k-monotone, completely monotone or threshold, respectively. A characterization of k-monotone clutters in terms of excluded minors is presented here. This result is used to derive a characterization of 2-monotone matroids and of 3-monotone matroids (which turn out to be all the threshold matroids). © 1993.

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Radially Symmetrical Flow Of Reacting Liquid With Changing Viscosity, S.E. Solovyov, V.A. Volpert, S.P. Davytan Aug 1993

Radially Symmetrical Flow Of Reacting Liquid With Changing Viscosity, S.E. Solovyov, V.A. Volpert, S.P. Davytan

Faculty Publications

Frontal regimens for one-dimensional flow of reacting liquid with changing viscosity are studied. Stationary solutions are investigated for the case of narrow reaction zones that shrink to a front. The results of numerical solution of the nonstationary problem are presented. Complex oscillations resulting from period-doubling bifurcations are found.

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Driven Diffusion, Kawasaki Dynamics, Mixing, And Spatial Ordering In An Interacting Lattice-Gas, Yan He, Ras B. Pandey Jul 1993

Driven Diffusion, Kawasaki Dynamics, Mixing, And Spatial Ordering In An Interacting Lattice-Gas, Yan He, Ras B. Pandey

Faculty Publications

Kawasaki dynamics is used to study the transport properties of a nonequilibrium steady state system of interacting lattice gas of oppositely charged particles in a linear gradient field in two dimensions. The rms displacements show unusual nondiffusive transport. The effective conductivity varies with the temperature which deviates from the Arrhenius law and depends on the range of interaction. Density of a fully mixed state decays with temperature with a power law. Onset of spatial ordering occurs in a certain temperature range at a fixed range of interaction.

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Greenland Ice Core “Signal” Characteristics: An Expanded View Of Climate Change, Paul A. Mayewski, L. David Meeker, Michael C. Morrison, Mark S. Twickler, Sallie I. Whitlow, Kevin K. Ferland, Debra A. Meese, M. R. Legrand, J. P. Steffensen Jul 1993

Greenland Ice Core “Signal” Characteristics: An Expanded View Of Climate Change, Paul A. Mayewski, L. David Meeker, Michael C. Morrison, Mark S. Twickler, Sallie I. Whitlow, Kevin K. Ferland, Debra A. Meese, M. R. Legrand, J. P. Steffensen

Faculty Publications

The last millenium of Earth history is of particular interest because it documents the environmental complexities of both natural variability and anthropogenic activity. We have analyzed the major ions contained in the Greenland Ice Sheet Project 2 (GISP 2) ice core from the present to ∼674 A.D. to yield an environmental reconstruction for this period that includes a description of nitrogen and sulfur cycling, volcanic emissions, sea salt and terrestrial influences. We have adapted and extended mathematical procedures for extracting sporadic (e.g., volcanic) events, secular trends, and periodicities found in the data sets. Finally, by not assuming that periodic components …

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Low‐Cost Technique For Preparing N‐Sb2S3/P‐Si Heterojunction Solar Cells, O. Savadogo, K. C. Mandal Jul 1993

Low‐Cost Technique For Preparing N‐Sb2S3/P‐Si Heterojunction Solar Cells, O. Savadogo, K. C. Mandal

Faculty Publications

No abstract provided.

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Stable Sets Versus Independent Sets, Guoli Ding Jul 1993

Stable Sets Versus Independent Sets, Guoli Ding

Faculty Publications

Let G=(V, E) be a graph and let L(G) be the set of stable sets of G. The matroidal number of G, denoted by m(G), is the smallest integer m such that L(G)=J1∪J2∪⋯∪Jm for some matroids Mi=(V,Ji)(i=1,2,...,m). We characterize the graphs of matroidal number at most m for all m≥1. For m≤3, we show that the graphs of matroidal number at most m can be characterized by excluding finitely many induced subgraphs. We also consider a similar problem which replaces 'union' by 'intersection'. © 1993.

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Omitted-Ability Bias And The Increase In The Return To Schooling, Mckinley L. Blackburn, David Neumark Jul 1993

Omitted-Ability Bias And The Increase In The Return To Schooling, Mckinley L. Blackburn, David Neumark

Faculty Publications

Over the 1980s, there were sharp increases in the return to schooling estimated with conventional wage regressions. We explore whether the relationship between ability and schooling changed over this period in ways that would have increased the schooling coefficient in these regressions. Our empirical results reject the hypothesis that an increase in the bias of the schooling coefficient, due to a change in the relationship between ability and schooling, has contributed to observed increases in the return to schooling.We also find that the increase in the schooling return has occurred for workers with relatively high levels of academic ability.

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A Decomposition Of Locally Finite Graphs, Bogdan Oporowski Jul 1993

A Decomposition Of Locally Finite Graphs, Bogdan Oporowski

Faculty Publications

We prove that every infinite, connected, locally finite graph G can be expressed as an edge-disjoint union of a leafless tree T, rooted at an arbitrarily chosen vertex of G, and a collection of finite graphs H1, H2, H3,...such that, for all i less than j, the vertices common to Hi and Hj lie in T, and no vertex of Hj lies on T between a vertex of Hi∩T and the root. © 1993.

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Three Points Of Great Height On Elliptic Curves, Andrew Bremner, Duncan A. Buell Jul 1993

Three Points Of Great Height On Elliptic Curves, Andrew Bremner, Duncan A. Buell

Faculty Publications

We give three elliptic curves whose generators have great height, demonstrating along the way a moderately efficient method for finding such points.

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Should The Characteristics Of Victims And Criminals Count? Payne V. Tennessee And Two Views Of Efficient Punishment, David D. Friedman Jul 1993

Should The Characteristics Of Victims And Criminals Count? Payne V. Tennessee And Two Views Of Efficient Punishment, David D. Friedman

Faculty Publications

No abstract provided.

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Formation Of O-Tyrosine And Dityrosine In Proteins During Radiolytic And Metal-Catalyzed Oxidation, Thomas G. Huggins, Mary C. Wells-Knecht, Nicholas A. Detorie, John W. Baynes, Suzanna R. Thorpe Jun 1993

Formation Of O-Tyrosine And Dityrosine In Proteins During Radiolytic And Metal-Catalyzed Oxidation, Thomas G. Huggins, Mary C. Wells-Knecht, Nicholas A. Detorie, John W. Baynes, Suzanna R. Thorpe

Faculty Publications

To evaluate their usefulness as chemical indicators of cumulative oxidative damage to proteins, we studied the kinetics and extent of formation of ortho-tyrosine (0-Tyr), dityrosine (DT), and dityrosine-like fluorescence (Ex = 3 17 nm, E,,, = 407 nm) in the model proteins RNase and lysozyme exposed to radiolytic and metalcatalyzed (H20z/Cu2+) oxidation (MCO). Although there were protein-dependent differences, o-Tyr, DT, and fluorescence increased coordinately during oxidation of the proteins in both oxidation systems. The contribution of DT to total dityrosine-like fluorescence in oxidized proteins varied from 2-10070, depending on the protein, type of oxidation, and extent of oxidative damage. In …

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Oxidized Amino Acids In Lens Protein With Age: Measurement Of O-Tyrosine And Dityrosine In The Aging Human Lens, Mary C. Wells-Knect, Thomas G. Huggins, Daniel G. Dyer, Suzanne R. Thorpe, John W. Baynes Jun 1993

Oxidized Amino Acids In Lens Protein With Age: Measurement Of O-Tyrosine And Dityrosine In The Aging Human Lens, Mary C. Wells-Knect, Thomas G. Huggins, Daniel G. Dyer, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

The concentrations of ortho-tyrosine (o-Tyr) and dityrosine (DT) were measured in noncataractous human lenses in order to assess the role of proteinoxidation reactions in the aging of lens proteins. The measurements were conducted by selected ion monitoring-gas chromatography/mass spectrometry using deuterium-labeled internal standards, which provided both high sensitivity and specificity for the quantitation of o-Tyr and DT. Between ages 1 and 78 years, the o-Tyr concentration in lens proteins varied from 0.3 to 0.9 mmol of o-Tyr/mol of Phe (n = 19), while DT ranged from 1 to 3 mumol of DT/mol of Tyr (n = 30). There were no …

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Ordering Processes In Porous-Media, J.C. Lee Jun 1993

Ordering Processes In Porous-Media, J.C. Lee

Faculty Publications

The ordering processes in a binary liquid mixture confined in a Vycor type of pore and at temperatures near the transition temperature of the pure system Tc are studied using a kinetic Ising model and the method of Monte Carlo simulations. The results for dynamics show quite clear signatures of the pore width but no notable difference between T > Tc and T < Tc. In the results for statics, the small angle part of the structure factor increases rapidly as T approaches Tc in the one-phase region. This suggests the onset of ordering but the fluctuation of …

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A Probabilistic Model And A Software Tool For Avcs Longitudinal Collision/Safety Analysis, H.-S. Jacob Tsao, Randolph Hall Jun 1993

A Probabilistic Model And A Software Tool For Avcs Longitudinal Collision/Safety Analysis, H.-S. Jacob Tsao, Randolph Hall

Faculty Publications

This paper develops a probabilistic model and a software tool for analyzing longitudinal collision/safety between two automated vehicles. The input parameters are the length of the gap between the two vehicles, the common speed prior to the failure, the reaction delay of the following vehicle and a bivariate pint distribution of the deceleration rates of the two vehicles. The output includes the probability of a collision and also the probability distribution of the relative speed at collision time.We will use this model to compare the safety consequences associated with the platooning and "free-agent" vehicle-following rules. We will also demonstrate that …

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Fast Accurate Simulation Of Large Shared Memory Multiprocessors, Bob Boothe Phd Jun 1993

Fast Accurate Simulation Of Large Shared Memory Multiprocessors, Bob Boothe Phd

Faculty Publications

Fast computer simulation is an essential tool in the design of large parallel computers. Our Fast Accurate Simulation Tool, FAST, is able to accurately simulate large shared memory multiprocessors and their execution of parallel applications at simulation speeds that are one to two orders of magnitude faster than previous comparable simulators. The key ideas involve execution driven simulation techniques that modify the object code of the application program being studied. This produces an augmented version of the code that is directly executed and performs much of the work of the simulation. We extend the previous work by introducing several new …

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Accumulation Of Maillard Reaction Products In Skin Collagen In Diabetes And Aging, Daniel G. Dyer, John A. Dunn, Suzanne R. Thorpe, Karen E. Bailie, Timothy L. Lyons, David R. Mccance, John W. Baynes Jun 1993

Accumulation Of Maillard Reaction Products In Skin Collagen In Diabetes And Aging, Daniel G. Dyer, John A. Dunn, Suzanne R. Thorpe, Karen E. Bailie, Timothy L. Lyons, David R. Mccance, John W. Baynes

Faculty Publications

To investigate the contribution of glycation and oxidation reactions to the modification of insoluble collagen in aging and diabetes, Maillard reaction products were measured in skin collagen from 39 type 1 diabetic patients and 52 nondiabetic control subjects. Compounds studied included fructoselysine (FL), the initial glycation product, and the glycoxidation products, N epsilon-(carboxymethyl) lysine (CML) and pentosidine, formed during later Maillard reactions. Collagen-linked fluorescence was also studied. In nondiabetic subjects, glycation of collagen (FL content) increased only 33% between 20 and 85 yr of age. In contrast, CML, pentosidine and fluorescence increased five-fold, correlating strongly with age. In diabetic patients, …

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Maillard Reaction Products And Their Relation To Complications In Insulin-Dependent Diabetes Mellitus, David R. Mccance, Daniel G. Dryer, John A. Dunn, Karen E. Bailie, Suzanne R. Thorpe, John W. Baynes, Timothy J. Lyons Jun 1993

Maillard Reaction Products And Their Relation To Complications In Insulin-Dependent Diabetes Mellitus, David R. Mccance, Daniel G. Dryer, John A. Dunn, Karen E. Bailie, Suzanne R. Thorpe, John W. Baynes, Timothy J. Lyons

Faculty Publications

Glycation, oxidation, and browning of proteins have all been implicated in the development of diabetic complications. We measured the initial Amadori adduct, fructoselysine (FL); two Maillard products, N epsilon-(carboxymethyl) lysine (CML) and pentosidine; and fluorescence (excitation = 328 nm, emission = 378 nm) in skin collagen from 39 type 1 diabetic patients (aged 41.5 +/- 15.3 [17-73] yr; duration of diabetes 17.9 +/- 11.5 [0-46] yr, [mean +/- SD, range]). The measurements were related to the presence of background (n = 9) or proliferative (n = 16) retinopathy; early nephropathy (24-h albumin excretion rate [AER24] > or = 20 micrograms/min; n …

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Large Amplitude L=1 Coherent Structures In Non-Neutral Plasmas Confined In A Cylindrical Trap, Ross L. Spencer, Grant W. Mason Jun 1993

Large Amplitude L=1 Coherent Structures In Non-Neutral Plasmas Confined In A Cylindrical Trap, Ross L. Spencer, Grant W. Mason

Faculty Publications

The computation of l= 1 coherent structures in non-neutral plasmas with arbitrary density profiles and for large displacements of the plasma from the symmetry axis of a confining cylindrical trap is described. As the structures are displaced from the axis, they revolve about the symmetry axis with a frequency that typically increases with displacement. The plasma also is distorted into an approximately elliptical shape. The frequency shifts and the eccentricities as a function of displacement, plasma size, and the shape of the density profile are both computed numerically and calculated analytically. The results are shown to be consistent with data …

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Clutters With Τ2=2Τ, Guoli Ding May 1993

Clutters With Τ2=2Τ, Guoli Ding

Faculty Publications

Motivated by Lehman's characterization of the minor-minimal clutters without the MFMC property, we propose a conjecture about the minor-minimal clutters with τk

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Photoluminescence And Absorption Studies Of Defects In Cdte And Znxcd1-Xte Crystals, Cheryl Barnett Davis, David D. Allred, A. Reyes-Mena, Jesus González-Hernández, Ovidio González, Bret C. Hess, Worth P. Allred May 1993

Photoluminescence And Absorption Studies Of Defects In Cdte And Znxcd1-Xte Crystals, Cheryl Barnett Davis, David D. Allred, A. Reyes-Mena, Jesus González-Hernández, Ovidio González, Bret C. Hess, Worth P. Allred

Faculty Publications

We have studied at cryogenic temperatures photoluminescence features which lie more than 0.15 eV below the band edge in ZnxCd1-xTe (0≤x≤0.09) crystals. The same features, namely a defect band which lies at about 0.13-0.20 eV below the band-gap energy and a peak at 1.1 eV, that are observed in pure CdTe samples are observed in these alloy materials. In annealed samples we observe that the 1.1 eV feature, which has been attributed to tellurium vacancies, increases with fast cooling. Increased concentrations of tellurium vacancies can be understood in terms of the phase diagram of CdTe which indicates that higher concentrations …

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Development Of New Methods For Assessing Solidification/Stabilization Of Hazardous Waste Using Solid-State Nuclear Magnetic Resonance Techniques (Ph.D Dissertation, Lsu), Michael A. Janusa May 1993

Development Of New Methods For Assessing Solidification/Stabilization Of Hazardous Waste Using Solid-State Nuclear Magnetic Resonance Techniques (Ph.D Dissertation, Lsu), Michael A. Janusa

Faculty Publications

New methods for assessing solidification/stabilization (S/S) of hazardous waste using solid-state nuclear magnetic resonance are developed for the purpose of diagnosing on a microscopic level the performance of S/S as a hazardous waste disposal technique. There are four techniques developed and described in this dissertation: (1) Solid-state deuterium NMR spectroscopy is used to determine if a particular deuterated organic waste is effectively solidified/stabilized and to determine the lower limit of the bond strength between the waste and the cement matrix; (2) Constant time pulsed field gradient ^ NMR spectroscopy is tested on a liquid waste encapsulated within a solidified matrix …

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Scaling Water And Energy Fluxes In Climate Systems: Three Land-Atmospheric Modeling Experiments, Eric F. Wood, Venkataraman Lakshmi May 1993

Scaling Water And Energy Fluxes In Climate Systems: Three Land-Atmospheric Modeling Experiments, Eric F. Wood, Venkataraman Lakshmi

Faculty Publications

The effects of small-scale heterogeneity in land-surface characteristics on the large-scale fluxes of water and energy in the land-atmosphere system have become a central focus of many of the climatology research experiments. The acquisition of high-resolution land-surface data through remote sensing and intensive land-climatology field experiments(like HAPEX and EIFE) has provided data to investigate the interactions between microscale land-atmosphere interactions and macroscale models. One essential research question is how to account for the small-scale heterogeneities and whether `effective' parameters can be used in the macroscale models. To address this question ofscaling, three modeling experiments were performed and are reviewed in …

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Cp-Odd Nucleon Potential, Vladimir Gudkov, Xiao-Gang He, Bruce H.J. Mckellar May 1993

Cp-Odd Nucleon Potential, Vladimir Gudkov, Xiao-Gang He, Bruce H.J. Mckellar

Faculty Publications

The P-odd and CP-odd nucleon potential for different models of CP violation in the one-meson exchange approximation is studied. It is shown that the main contribution is due to the π-meson exhcange which leads to a simple one-parameter CP-odd nucleon potential.

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Evidence Of A Nondiffusive Transport In A Monodisperse Screened Coulomb System By A Molecular-Dynamics Simulation, Michael Wild, Ras B. Pandey May 1993

Evidence Of A Nondiffusive Transport In A Monodisperse Screened Coulomb System By A Molecular-Dynamics Simulation, Michael Wild, Ras B. Pandey

Faculty Publications

A molecular-dynamics simulation is carried out for particles (tracers) interacting with a screened Coulomb potential in three dimensions. A phase transition is observed from a liquid to an fcc solid on reducing the temperature at a fixed density, consistent with previous studies. In the liquid phase, the variation of the rms displacement Rtr of the charged particles with time seems to depend on the density and the temperature. In the short-time regime, the effective exponent k for the subdiffusive power-law behavior, i.e., Rtr∼tk, decreases on increasing the density and lowering the temperature. A crossover from …

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Another Cautionary Note On Interpreting Regression Results In Family Research: A Comment On Peterson And Gerson (1992), Alan J. Hawkins, Joseph A. Olsen, Richard R. Peterson, Kathleen Gerson May 1993

Another Cautionary Note On Interpreting Regression Results In Family Research: A Comment On Peterson And Gerson (1992), Alan J. Hawkins, Joseph A. Olsen, Richard R. Peterson, Kathleen Gerson

Faculty Publications

Occasionally in the family literature we receive reminders to be cautious about our interpretations of regressions results (e.g., Glenn & Kramer, 1985; Glenn & Shelton, 1983). After all, regression results are stated in the language of mathematics. We must be careful when we translate from the language of mathematics, which is blind to the human situation being represented by the numbers, into language that is meaningful in the human context. This brief not critiques the interpretation of regression results in an article by Peterson and Gerson (1992) that appeared in a recent issue of the Journal of Marriage and the …

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Dissipative Effects On The Mean Square Displacement Of An Oscillator, X. L. Li, G. W. Ford, R. F. O'Connell Apr 1993

Dissipative Effects On The Mean Square Displacement Of An Oscillator, X. L. Li, G. W. Ford, R. F. O'Connell

Faculty Publications

The localization of an oscillator in a dissipative environment may be characterized by its mean square displacement. In the case of a general heat bath, we write down an expression for this quantity as an integral involving the imaginary part of the generalized susceptibility. This integral is evaluated explicitly in the case of both Ohmic and blackbody radiation heat baths, leading us to the conclusion that localization is enhanced by an increase of dissipation or oscillator fequency (binding) and by a decrease in temperature. © 1993.

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On The Distribution Of Sums Of Residues, Jerrold R. Griggs Apr 1993

On The Distribution Of Sums Of Residues, Jerrold R. Griggs

Faculty Publications

No abstract provided.

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Disjoint Circuits On A Klein Bottle And A Theorem On Posets, Guoli Ding Mar 1993

Disjoint Circuits On A Klein Bottle And A Theorem On Posets, Guoli Ding

Faculty Publications

In this paper, we consider the problem of packing disjoint directed circuits in a digraph drawn on the Klein bottle or on the torus. We formulate a problem on posets which unifies all the problems considered by Ding et al. and by Seymour. Then we generalize all the results of their two papers by proving a theorem on our special posets. © 1993.

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Low-Frequency Feature In The First-Order Raman Spectrum Of Amorphous Carbon, David D. Allred, Qi Wang, Jesus González-Hernández Mar 1993

Low-Frequency Feature In The First-Order Raman Spectrum Of Amorphous Carbon, David D. Allred, Qi Wang, Jesus González-Hernández

Faculty Publications

In the first-order Raman spectrum of amorphous carbon (a-C) there is a low-frequency feature in the 200-900-cm-1 region. This feature is characteristic of the highly disordered amorphous-carbon materials. We note that the intensity of this feature is very sensitive to the thermal history of samples, thus suggesting that it is an important measure of the degree of disorder of the a-C materials. We also discuss the relationship between this feature and the phonon density of states of graphite.

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Exponential Growth Of An Unstable L=1 Diocotron Mode For A Hollow Electron Column In A Warm-Fluid Model, S. Neil Rasband, Ross L. Spencer, Richard R. Vanfleet Mar 1993

Exponential Growth Of An Unstable L=1 Diocotron Mode For A Hollow Electron Column In A Warm-Fluid Model, S. Neil Rasband, Ross L. Spencer, Richard R. Vanfleet

Faculty Publications

Numerical investigations of a warm-fluid model with an isothermal equation of state for the perpendicular dynamics of an axisymmetric, magnetically confined pure electron plasma predict an exponentially unstable, l=1, diocotron mode for hollow density profiles. The unstable mode can be identified with a stable, nonsmooth mode that exists in cold drift models but which is destabilized by finite temperature effects. The unstable mode has many properties similar to the experimental results reported by Driscoll [Phys. Rev. Lett. 64, 645 (1990)].

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