Digital Commons Network^™

Observation Of Scaling Violations In Scaled Momentum Distributions At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of x and Q2 using the ZEUS detector. The evolution of the scaled momentum, xp, with Q2, in the range 10 to 1280 GeV2, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of Q2. © 1997 Elsevier Science B.V.

Chern-Simons States In Spin-Network Quantum Gravity, Rodolfo Gambini, Jorge Griego, Jorge Pullin

Faculty Publications

In the context of canonical quantum gravity in terms of Ashtekar's new variables, it is known that there exists a state that is annihilated by all the quantum constraints and that is given by the exponential of the Chern-Simons form constructed with the Asthekar connection. We make a first exploration of the transform of this state into the spin-network representation of quantum gravity. The discussion is limited to trivalent nets with planar intersections. We adapt an invariant of tangles to construct the transform and study the action of the Hamiltonian constraint on it. We show that the first two coefficients …

Observation Of Isolated High-ET Photons In Photoproduction At Hera: Zeus Collaboration, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

Events containing an isolated prompt photon with high transverse energy, together with a balancing jet, have been observed for the first time in photoproduction at HERA. The data were taken with the ZEUS detector, in a γp centre of mass energy range 120-250 GeV. The fraction of the incoming photon energy participating in the production of the prompt photon and the jet, xγ, shows a strong peak near unity, consistent with LO QCD Monte Carlo predictions. In the transverse energy and pseudorapidity range 5 ≤ EγT < 10 GeV, -0.7 ≤ ηγ < 0.8, EjetT ≥ 5 GeV, and -1.5 ≤ ηjet ≤ 1.8, with xOBSγ > 0.8, the measured cross section is 15.3 ± 3.8 ± 1.8 pb, in good …

Unavoidable Minors Of Large 3-Connected Matroids, Guoli Ding, Bogdan Oporowski, James Oxley, Dirk Vertigan

Faculty Publications

This paper proves that, for every integernexceeding two, there is a numberN(n) such that every 3-connected matroid with at leastN(n) elements has a minor that is isomorphic to one of the following matroids: an (n+2)-point line or its dual, the cycle or cocycle matroid ofK3,n, the cycle matroid of a wheel withnspokes, a whirl of rankn, or ann-spike. A matroid is of the last type if it has ranknand consists ofnthree-point lines through a common point such that, for allkin {1,2,...,n-1}, the union of every set ofkof these lines has rankk+1. © 1997 Academic Press.

Robotic Tcf And Rigid-Body Calibration Methods, Edward Red, Xuguang Wang

Faculty Publications

For off-line programming to work, systematic methods must be developed to account for non-ideal performance of the parts and devices in the manufacturing cell. Although much of the literature focuses on robot inaccuracy, this paper considers practical methods for the tool control frame (TCF) calibration and rigid-body compensation required to close the inverse kinematics loop for target driven tasks.

Nonuniversal Scaling And Conformational Crossover Of Polymer Chains In An Electrophoretic Deposition, Grace M. Foo, Ras B. Pandey

Faculty Publications

A computer simulation model of electrodeposition of polymer chains on an impenetrable wall is used to evaluate the power-law scaling exponents (ν_x(y)) for the longitudinal and transverse spread, R_gx(y)∼L_c^ν_x(y); we find that the exponents ν_x(y) depend on the field strength, i.e., they are nonuniversal. A conformational crossover is observed for the transverse spread from the bulk with ν_y≃1/3-2/3 to the wall with ν_y≃2/3-1. A similar crossover also occurs for the longitudinal component of R_g but with an opposite trend, i.e., magnitude of ν_x is larger …

Evaluation Of Special Sensor Microwave/Imager Satellite Data For Regional Soil Moisture Estimation Over The Red River Basin, Venkataraman Lakshmi, Eric F. Wood, Bhaskar J. Choudhury

Faculty Publications

Regional-scale estimation of soil moisture using in situ field observations is not possible due to problemswith the representativeness of the sampling and costs. Remotely sensed satellite data are helpful in this regard.Here, the simulations of 19- and 37-GHz vertical and horizontal polarization brightness temperatures and estimationof soil moistures using data from the Special Sensor Microwave/Imager (SSM/I) for 798 0.258 3 0.258boxes in the southwestern plains region of the United States for the time period between 1 August 1987 and31 July 1988 are presented. A coupled land-canopy–atmosphere model is used for simulating the brightnesstemperatures. The land-surface hydrology is modeled using a …

A Novel Laboratory Course On Advanced Chemical Engineering Experiments, Jochen A. Lauterbach, S. White, X. Lui, G. M. Bodner, W. N. Delgass

Faculty Publications

The chemical engineering curriculum in the United States has trained generations of technical experts who have successfully optimized chemical processes and products once they entered the chemical industry. The U.S. chemical industry, however, has entered a critical stage in which it must be able to create new and differentiated value through technical innovations that arc essential for long-term survival. This innovation process will require new skills that go far beyond the traditional expertise for the optimization of tasks possessed by young chemical engineers. The innovators must be able to identify new opportunities, explore the boundaries of technology, evaluate critical issues, …

System For Electron Paramagnetic Resonance Measurements At High Pressure And Low Temperature, Ke Huang, Daniel L. Decker, H. Mark Nelson, J. Dean Barnett

Faculty Publications

Major improvements have been made on the sensitive high pressure electron paramagnetic resonance (EPR) system developed previously in 1978 at this laboratory. These changes allow low temperature measurements and provide a more stable signal. The high pressure EPR cell is placed inside a vacuum chamber to provide thermal isolation, so that the system may be cooled by a closed cycle refrigerator to temperatures between 45 and 60 K, depending on the energy input to the modulation coil. The combination of high pressure and low temperature greatly expands the thermodynamic range over which EPR measurements can be made. An improved and …

Crossover Dynamics For Polymer Simulation In Porous Media, V. Yamakov, D. Stauffer, A. Milchev, G.M. Foo, R.B. Pandey

Faculty Publications

Off-lattice Monte Carlo simulations show anomalous diffusion at intermediate times without a clear Rouse regime, for the motion of chains through a random porous medium.

Measurement Of The Proton Structure Function F2 And ΣΓ*ΡTot At Low Q2 And Very Low X At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, E. Anselmo, R. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

A small electromagnetic sampling calorimeter, installed in the ZEUS experiment in 1995, significantly enhanced the acceptance for very low x and low Q2 inelastic neutral current scattering, e+p → e+X, at HERA. A measurement of the proton structure function F2 and the total virtual photon-proton (γ*p) cross-section is presented for 0.11 ≤ Q2 ≤ 0.65 GeV2 and 2 × 10-6 ≤ x ≤ 6 × 10-5, corresponding to a range in the γ*p c.m. energy of 100 ≤ W ≤ 230 GeV. Comparisons with various models are also presented. © 1997 Published by Elsevier Science B.V.

D* Production In Deep Inelastic Scattering At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, R. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

This paper presents measurements of D*f± production in deep inelastic scattering from collisions between 27.5GeV positrons and 820GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel D*+ → (D0 → K-π+)π+ (+c.c.) has been used in the study. The e+p cross section for inclusive D*± production with 5 < Q2 < 100GeV2 and y < 0.7 is 5.3±1.0±0.8nb in the kinematic region 1.3 < pT(D*±) < 9.0GeV and |η(D*±) | < 1.5. Differential cross sections as functions of pT(D*±), η(D*±), W and Q2 are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in pT(D*±) and η(D*±), the charm contribution Fcc̄2(x,Q2) to the proton structure function is determined for Bjorken x between 2 · 10-4 and 5 · 10-3. © 1997 Elsevier Science B.V.

Local Refinement Of Three-Dimensional Finite Element Meshes, M. L. Staten, Norman L. Jones

Faculty Publications

Mesh refinement is an important tool for editing finite element meshes in order to increase the accuracy of the solution. Refinement is performed in an iterative procedure in which a solution is found, error estimates are calculated, and elements in regions of high error are refined. This process is repeated until the desired accuracy is obtained.

Much research has been done on mesh refinement. Research has been focused on two-dimensional meshes and three-dimensional tetrahedral meshes ([1] Ning et al. (1993) Finite Elements in Analysis and Design, 13, 299–318; [2] Rivara, M. (1991) …

A Fluid In Contact With A Semipermeable Surface: Second-Order Integral Equation Approach, Douglas Henderson, Pawel Bryk, Stefan Sokolowski

Faculty Publications

An integral equation approach for a binary hard-sphere mixture interacting with a planar semipermeable wall (membrane) is formulated by using the second-order nonuniform or pair Ornstein–Zernike equation as well as the usual singlet Ornstein–Zernike equation. The results of the pair theory are compared with those obtained from the singlet theory and with computer simulation data. The pair approach is more accurate than the singlet theory.

Age-Dependent Increase In Ortho-Tyrosine And Methionine Sulfoxide In Human Skin Collagen Is Not Accelerated In Diabetes: Evidence Against A Generalized Increase In Oxidative Stress In Diabetes, Mary C. Wells-Knecht, Timothy J. Lyons, David R. Mccance, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

The glycoxidation products Nepsilon-(carboxymethyl)lysine and pentosidine increase in skin collagen with age and at an accelerated rate in diabetes. Their age-adjusted concentrations in skin collagen are correlated with the severity of diabetic complications. To determine the relative roles of increased glycation and/or oxidation in the accelerated formation of glycoxidation products in diabetes, we measured levels of amino acid oxidation products, distinct from glycoxidative modifications of amino acids, as independent indicators of oxidative stress and damage to collagen in aging and diabetes. We show that ortho-tyrosine and methionine sulfoxide are formed in concert with Nepsilon-(carboxymethyl)lysine and pentosidine during glycoxidation of collagen …

A Unified Green's Function Analysis Of Complicated Dfb Lasers, Jim D. Freeze, Michael A. Jensen, Richard H. Selfridge

Faculty Publications

An efficient full-wave analysis technique for one-dimensional optical domains, known as the recursive Green's function method (RGFM), is presented for evaluation of distributed feedback (DFB) laser cavities with arbitrary material profiles. The method first constructs the Green's function of an inhomogeneous domain and subsequently uses Green's theorem to determine the laser optical field, lasing wavelength, and threshold gain. The technique is applied to investigate the performance of three DFB laser structures: a chirped-grating configuration, a modulated stripe width design, and a reduced duty cycle complex-coupled device. These structures are evaluated in terms of their single-mode lasing behavior and the uniformity …

Evolution And Nebulousness In Theories, Barry N. Markovsky

Faculty Publications

Social scientists have a clear choice in how they may approach theory development. One path leads to "nebulous" theories that lack any real explanatory power. The other path capitalizes on evolutionary principles of variation and selection, vastly increasing the chances for explanatory success. I illustrate these ideas by reference to "artificial life" programs, and discuss the implications for theory construction in the social sciences.

Singular And Plural Non-Deterministic Parameters, Sigurd Meldal, M. A. Walicki

Faculty Publications

The article defines algebraic semantics of singular (call-time-choice) and plural (run-time-choice) nondeterministic parameter passing and presents a specification language in which operations with both kinds of parameters can be defined simultaneously. Sound and complete calculi for both semantics are introduced. We study the relations between the two semantics and point out that axioms for operations with plural arguments may be considered as axiom schemata for operations with singular arguments.

Law Reform In Vietnam: The Uneven Legacy Of Doi Moi, Spencer Weber Waller, Lan Cao

Faculty Publications

No abstract provided.

In Search Of The Lost Chord: Reflections On The 1996 Item Veto Act, Neal Devins

Faculty Publications

No abstract provided.

A Body Without Organs: Three Approaches- Cage, Bach, And Messiaen, Christian T. Asplund

Faculty Publications

Allow me to posit a traditional four-part division of the self into the spiritual, intellectual, emotional, and physical/sensual. This may be further simplified to a two-part division, one being the spiritual and the other being a trio of the other selves which collectively may be termed the natural self. Sacred activity in this context would be an effort to achieve communion between the spiritual self and other spiritual entities. Such communion would be, in fact, the self's highest goal and, ultimately, the only one worth all its efforts. True communion with other beings is only possible on this spiritual level, …

Numerical Modeling Of Self-Propagating Polymerization Fronts: The Role Of Kinetics On Front Stability, Stanislav E. Solovyov, Victor M. Ilyashenko, John A. Pojman

Faculty Publications

Frontal propagation of a highly exothermic polymerization reaction in a liquid is studied with the goal of developing a mathematical model of the process. As a model case we consider monomers such as methacrylic acid and n-butyl acrylate with peroxide initiators, although the model is not limited to these reactants and can be applied to any system with the similar basic polymerization mechanism. A three-step reaction mechanism, including initiation, propagation and termination steps, as well as a more simple one-step mechanism, were considered. For the one-step mechanism the loss of stability of propagating front was observed as a sequence …

The Future Information Infrastructure In Economics, William L. Goffe, Robert P. Parks

Faculty Publications

No abstract provided.

Differential Cross Sections Of D*± Photoproduction In Ep Collisions At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, R. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, I. Gialas, R. Giusti, G. Iacobucci, G. Laurenti, G. Levi

Faculty Publications

Inclusive photoproduction of D*± in ep collisions at HERA has been measured with the ZEUS detector for photon-proton centre of mass energies in the range 115 < W < 280 GeV and photon virtuality Q2 < 4 GeV2. The cross section σ → D*X integrated over the kinematic region pDz.ast;⊥ > 3 GeV and -1.5 < ηD* < 1.0 is (10.6 ± 1.7(stat.) ± 1.61.3 (syst.)) nb. Differential cross sections as functions of pD*⊥, ηD* and W are given. The data are compared with two next-to-leading order perturbative QCD predictions. For a calculation using a massive charm scheme the predicted cross sections are smaller than the measured ones. A recent calculation using a massless charm scheme is in agreement with the data. © 1997 Published by Elsevier Science B.V.

Carboxymethylethanolamine, A Biomarker Of Phospholipid Modification During The Maillard Reaction In Vivo, Jesus R. Requena, Mahtab U. Ahmed, C. Wesley Fountain, Thorsten P. Degenhardt, Sharanya Reddy, Cliff Perez, Timothy J. Lyons, Alicia J. Jenkins, John W. Baynes, Suzanne R. Thorpe

Faculty Publications

Nepsilon-(Carboxymethyl)lysine (CML) is a stable chemical modification of proteins formed from both carbohydrates and lipids during autoxidation reactions. We hypothesized that carboxymethyl lipids such as (carboxymethyl)phosphatidylethanolamine (carboxymethyl-PE) would also be formed in these reactions, and we therefore developed a gas chromatography-mass spectrometry assay for quantification of carboxymethylethanolamine (CME) following hydrolysis of phospholipids. In vitro, CME was formed during glycation of dioleoyl-PE under air and from linoleoylpalmitoyl-PE, but not from dioleoyl-PE, in the absence of glucose. In vivo, CME was detected in lipid extracts of red blood cell membranes, approximately 0.14 mmol of CME/mol of ethanolamine, from control and diabetic subjects, …

Grand Canonical Monte Carlo And Modified Singlet Integral Equations For The Density Profile Of A Yukawa Fluid Near A Planar Wall, Douglas Henderson, Wilmer Olivares-Rivas, Leo Degreve, Jacqueline Quintana

Faculty Publications

Results for the density profile for Yukawa molecules near a hard wall and an exponential attractive wall are presented for Grand Canonical Monte Carlo (GCMC) simulations, for the singlet hypernetted chain (HNC) integral equation and for a modified version of the Lovett–Mou–Buff–Wertheim (LMBW-1) which uses the exact contact value theorem. The results of the standard singlet HNC are quite poor. If the LMBW equation is modified (but still using the bulk direct correlation function) the results at high temperature become reasonable. However, the results at low temperatures, close to the bulk coexistence curve, are only a partial improvement. The contact …

234Th And 210Pb Evidence For Rapid Ingestion Of Settling Particles By Mobile Epibenthic Megafauna In The Abyssal Ne Pacific, L. M. L. Lauerman, J. M. Smoak, Timothy J. Shaw, W. S. Moore, K. L. Smith Jr.

Faculty Publications

No abstract provided.

The Probability Density Function Of Ocean Surface Slopes And Its Effects On Radar Backscatter, Y. Liu, Xh Yan, W.T. Liu, P.A. Hwang

Faculty Publications

Based on Longuet-Higgins's theory of the probability distribution of wave amplitude and wave period and on some observations, a new probability density function (PDF) of ocean surface slopes is derived. It is f(zeta(x), zeta(y)) = n/2 pi(n - 1)sigma(u) sigma(c) x [1 + zeta(x)(2)/(n - 1)sigma(n)(2) + zeta(y)(2)/(n - 1)sigma(c)(2)](-(n + 2)/2) + skewness, where zeta(x) and zeta(y) are the slope components in upwind and crosswind directions, respectively; sigma(u)(2) and sigma(c)(2) are the corresponding mean-square slopes. The peakedness of slopes is generated by nonlinear wave-wave interactions in the range of gravity waves. The skewness of slopes is generated by nonlinear …

Intrinsic Decoherence In Mesoscopic Systems, P. Mohanty, E. M.Q. Jariwala, Richard A. Webb

Faculty Publications

We present measurements of the phase coherence time τ_φ in six quasi-1D Au wires and clearly show that τ_φ is temperature independent at low temperatures. We suggest that zero-point fluctuations of the phase coherent electrons are responsible for the observed saturation of τ_φ. We introduce a new functional form for the temperature dependence and present the results of a calculation for the saturation value of τ_φ. This explains the observed temperature dependence of our samples as well as many 1D and 2D systems reported to date.

Conformation Of Interacting Polymer Chains: Effects Of Temperature, Bias, Polymer Concentration, And Porosity, Grace M. Foo, Ras B. Pandey

Faculty Publications

The conformations of interacting polymer chains driven by a biased field in heterogeneous media are studied using Monte Carlo simulations in three dimensions. In addition to excluded volume, a nearest-neighbor interaction is considered with polymer-polymer repulsion and polymer-solvent attraction. Two types of heterogeneous media are considered: (i) a homogeneous-annealed system consisting of mobile polymer chains and solvents and (ii) quenched porous media, generated by adding a random distribution of quenched barriers. Effects of polymer concentration (p), bias (B), temperature (T), and porosity (p_s) on the magnitude of the radius of gyration (R_g) of the …