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Full-Text Articles in Physical Sciences and Mathematics

A Simple Surface Temperature Assimilation Scheme For Use In Land Surface Models, Venkataraman Lakshmi Dec 2000

A Simple Surface Temperature Assimilation Scheme For Use In Land Surface Models, Venkataraman Lakshmi

Faculty Publications

This paper examines the utilization of surface temperature as a variable which can be assimilated in off-line land surface hydrological models. The connection between the surface temperature and evapotranspiration is utilized in making adjustments to the model-computed surface soil moisture. This adjustment is a function of the difference between the model-computed and the observed surface temperature. Comparisons between the model-computed and satellite-observed surface temperatures have been carried out. The assimilation of surface temperature is carried out twice a day (corresponding to the A.M. and P.M. overpass of the NOAA 10) over the Red-Arkansas basin in the southwestern United States (31°50′N-36°N, …


Simplified Calculation Of The Stability Matrix For Semiclassical Propagation, Sophya Garashchuk, John C. Light Dec 2000

Simplified Calculation Of The Stability Matrix For Semiclassical Propagation, Sophya Garashchuk, John C. Light

Faculty Publications

We present a simple method of calculation of the stability (monodromy) matrix that enters the widely used semiclassical propagator of Herman and Kluk and almost all other semiclassical propagators. The method is based on the unitarity of classical propagation and does not involve any approximations. The number of auxiliary differential equations per trajectory scales linearly rather than quadratically with the system size. Just the first derivatives of the potential surface are needed. The method is illustrated on the collinear H[sub 3] system.


The Averaging Lemma, Ronald A. Devore, Guergana Petrova Nov 2000

The Averaging Lemma, Ronald A. Devore, Guergana Petrova

Faculty Publications

No abstract provided.


Basaltic Lava Domes, Lava Lakes, And Volcanic Segmentation On The Southern East Pacific Rise, Scott M. White, Ken C. Macdonald, Rachel M. Haymon Oct 2000

Basaltic Lava Domes, Lava Lakes, And Volcanic Segmentation On The Southern East Pacific Rise, Scott M. White, Ken C. Macdonald, Rachel M. Haymon

Faculty Publications

Meter-scale DSL-120 sonar mapping and coregistered Argo II photographic observations reveal changes in eruptive style that closely follow the third-order structural segmentation of the ridge axis on the southern East Pacific Rise, 17o11'-18o37'S. Near segment ends we observe abundant basaltic lava domes which average 20 rn in height and 200 rn in basal diameter and have pillow lava as the dominant lava morphology. The ubiquity of pillow lava suggests low effusion rate eruptions. The abundance of lava domes suggests that the fissure eruptions were of sufficient duration to focus and produce a line of volcanic edifices. …


Effect Of Collagen Turnover On The Accumulation Of Advanced Glycation End Products, Nicole Verzijl, Jeroen Degroot, Suzanne R. Thorpe, Ruud A. Bank, J. Nikki Shaw, Timothy J. Lyons, Johannes Wj Bijlsma, Floris Pjg Lafeber, John W. Baynes, Johan M. Tekoppele Sep 2000

Effect Of Collagen Turnover On The Accumulation Of Advanced Glycation End Products, Nicole Verzijl, Jeroen Degroot, Suzanne R. Thorpe, Ruud A. Bank, J. Nikki Shaw, Timothy J. Lyons, Johannes Wj Bijlsma, Floris Pjg Lafeber, John W. Baynes, Johan M. Tekoppele

Faculty Publications

Collagen molecules in articular cartilage have an exceptionally long lifetime, which makes them susceptible to the accumulation of advanced glycation end products (AGEs). In fact, in comparison to other collagen-rich tissues, articular cartilage contains relatively high amounts of the AGE pentosidine. To test the hypothesis that this higher AGE accumulation is primarily the result of the slow turnover of cartilage collagen, AGE levels in cartilage and skin collagen were compared with the degree of racemization of aspartic acid (% D-Asp, a measure of the residence time of a protein). AGE (Ne- (carboxymethyl)lysine, Ne-(carboxyethyl)lysine, and pentosidine) and % D-Asp concentrations increased …


An Approximation To Miscible Fluid Flows In Porous Media With Point Sources And Sinks By An Eulerian-Lagrangian Localized Adjoint Method And Mixed Finite Element Methods, Hong Wang, Liang Dong, Richard E. Ewing, Stephen L. Lyons, Guan Qin Aug 2000

An Approximation To Miscible Fluid Flows In Porous Media With Point Sources And Sinks By An Eulerian-Lagrangian Localized Adjoint Method And Mixed Finite Element Methods, Hong Wang, Liang Dong, Richard E. Ewing, Stephen L. Lyons, Guan Qin

Faculty Publications

We develop an Eulerian–Lagrangian localized adjoint method (ELLAM)-mixed finite element method (MFEM) solution technique for accurate numerical simulation of coupled systems of partial differential equations (PDEs), which describe complex fluid flow processes in porous media. An ELLAM, which was shown previously to outperform many widely used methods in the context of linear convection-diffusion PDEs, is presented to solve the transport equation for concentration. Since accurate fluid velocities are crucial in numerical simulations, an MFEM is used to solve the pressure equation for the pressure and Darcy velocity. This minimizes the numerical difficulties occurring in standard methods for approximating velocities caused …


Pyridoxamine, An Inhibitor Of Advanced Glycation Reactions, Also Inhibits Advanced Lipoxidation Reactions: Mechanism Of Action Of Pyridoxamine, Joelle M. Onorato, Alicia J. Jenkins, Suzanne R. Thorpe, John W. Baynes Jul 2000

Pyridoxamine, An Inhibitor Of Advanced Glycation Reactions, Also Inhibits Advanced Lipoxidation Reactions: Mechanism Of Action Of Pyridoxamine, Joelle M. Onorato, Alicia J. Jenkins, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

Maillard or browning reactions lead to formation of advanced glycation end products (AGEs) on protein and contribute to the increase in chemical modification of proteins during aging and in diabetes. AGE inhibitors such as aminoguanidine and pyridoxamine (PM) have proven effective in animal model and clinical studies as inhibitors of AGE formation and development of diabetic complications. We report here that PM also inhibits the chemical modification of proteins during lipid peroxidation (lipoxidation) reactions in vitro, and we show that it traps reactive intermediates formed during lipid peroxidation. In reactions of arachidonate with the model protein RNase, PM prevented modification …


Low Temperature Anomaly In Mesoscopic Kondo Wires, P. Mohanty, Richard A. Webb May 2000

Low Temperature Anomaly In Mesoscopic Kondo Wires, P. Mohanty, Richard A. Webb

Faculty Publications

We report the observation of an anomalous magnetoresistance in extremely dilute quasi-one-dimensional AuFe wires at low temperatures, along with a hysteretic background at low fields. The Kondo resistivity does not show the unitarity limit down to the lowest temperature, implying uncompensated spin states. We suggest that the anomalous magnetoresistance may be understood as the interference correction from the accumulation of geometric phase in the conduction electron wave function around the localized impurity spin.


3d Outside Cell Interference Factor For An Air-Ground Cdma ‘Cellular’ System, David W. Matolak May 2000

3d Outside Cell Interference Factor For An Air-Ground Cdma ‘Cellular’ System, David W. Matolak

Faculty Publications

We compute the outside-cell interference factor of a code-division multiple-access (CDMA) system for a three-dimensional (3-D) air-to-ground (AG) "cellular-like" network consisting of a set of uniformly distributed ground base stations and airborne mobile users. The CDMA capacity is roughly inversely proportional to the outside-cell interference factor. It is shown that for the nearly free-space propagation environment of these systems, the outside-cell interference factor can be larger than that for terrestrial propagation models (as expected) and depends approximately logarithmically upon both the cell height and cell radius.


Ac Susceptibility Of Sr3CuptXIr1-XO6: A Magnetic System With Competing Interactions And Dimensionality, S H. Irons, T D. Sangrey, K M. Beauchamp, M D. Smith, Hans Conrad Zur Loye May 2000

Ac Susceptibility Of Sr3CuptXIr1-XO6: A Magnetic System With Competing Interactions And Dimensionality, S H. Irons, T D. Sangrey, K M. Beauchamp, M D. Smith, Hans Conrad Zur Loye

Faculty Publications

Sr3CuPtxIr1-xO6 has been cited as an example of a one-dimensional quantum spin chain with competing ferromagnetic and antiferromagnetic interactions. We have measured the ac susceptibility of Sr3CuPtxIr1-xO6 with x=0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7, in magnetic fields of 0–60 kOe, and at temperatures down to 0.275 K. Our data show that the x=endpoint Sr3CuIrO6, exhibits long-range ferromagnetic order at T=20.1 K, contrary to results from dc susceptibility studies which indicated that it remained a one-dimensional ferromagnet to below 4 …


An Optimal-Order Error Estimate For An Ellam Scheme For Two-Dimensional Linear Advection-Diffusion Equations, Hong Wang Apr 2000

An Optimal-Order Error Estimate For An Ellam Scheme For Two-Dimensional Linear Advection-Diffusion Equations, Hong Wang

Faculty Publications

An Eulerian-Lagrangian localized adjoint method (ELLAM) is presented and an- alyzed for two-dimensional linear advection-diffusion partial differential equations (PDEs). An optimal-order error estimate in the L^2 norm and a superconvergence estimate in a discrete H^1 norm are derived. Numerical experiments are performed to verify the theoretical estimates.


Comparison Of Tovs-Derived Land Surface Variables With Ground Observations, Venkataraman Lakshmi, Joel Susskind Jan 2000

Comparison Of Tovs-Derived Land Surface Variables With Ground Observations, Venkataraman Lakshmi, Joel Susskind

Faculty Publications

The Tiros Operational Vertical Sounder (TOVS) Pathfinder Path A retrieved surface skin temperature, surface air temperatures, and surface specific humidity are compared with data obtained from three large-scale field campaigns: the First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment (FIFE), the Hydrologic Atmospheric Pilot Experiment (HAPEX) in the Sahel, and the Boreal Ecosystem-Atmosphere Study (BOREAS). The long-term estimates of surface skin temperatures, surface air temperatures, and surface vapor pressure were unbiased, and the standard deviations of the errors were about 4°C, 3.5°C, and 3.5 mbar, respectively. The monthly mean variables obtained from the TOVS data at four times …


Structural And Electrical Characterization Of A Novel Mixed Conductor: Ceo2 - Sm2O3 - Zro2 Solid Solution, W. Huang, P. Shuk, M. Greenblatt, M. Croft, Fanglin Chen, M. Liu Jan 2000

Structural And Electrical Characterization Of A Novel Mixed Conductor: Ceo2 - Sm2O3 - Zro2 Solid Solution, W. Huang, P. Shuk, M. Greenblatt, M. Croft, Fanglin Chen, M. Liu

Faculty Publications

solid solutions were synthesized for the first time by the hydrothermal method. The electrical properties of the solid solutions have been studied in air and under reducing conditions. Solid solutions with the fluorite structure were formed in all of the studied range of substitution after calcination at 1500°C. With increasing substitution up to 30 mol %, the electronic conductivity increases under a reducing atmosphere. The solid solution has good mixed electronic and ionic conductivity; the total conductivity is 0.42 S/cm at and 700°C with an estimated ionic conductivity of ca. .


Simplified Calculation Of The Stability Matrix For Semiclassical Propagation, Sophya V. Garashchuk, J. C. Light Jan 2000

Simplified Calculation Of The Stability Matrix For Semiclassical Propagation, Sophya V. Garashchuk, J. C. Light

Faculty Publications

We present a simple method of calculation of the stability (monodromy) matrix that enters the widely used semiclassical propagator of Herman and Kluk and almost all other semiclassical propagators. The method is based on the unitarity of classical propagation and does not involve any approximations. The number of auxiliary differential equations per trajectory scales linearly rather than quadratically with the system size. Just the first derivatives of the potential surface are needed. The method is illustrated on the collinear H3 system.