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1998

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Articles 181 - 210 of 2574

Full-Text Articles in Physical Sciences and Mathematics

A Late Cambrian Positive Carbon-Isotope Excursion In The Southern Appalachians: Relation To Biostratigraphy, Sequence Stratigraphy, Environments Of Deposition, And Diagenesis, Bosiljka Glumac, Kenneth R. Walker Nov 1998

A Late Cambrian Positive Carbon-Isotope Excursion In The Southern Appalachians: Relation To Biostratigraphy, Sequence Stratigraphy, Environments Of Deposition, And Diagenesis, Bosiljka Glumac, Kenneth R. Walker

Geosciences: Faculty Publications

A positive carbon-isotope excursion is recorded within the Upper Cambrian sedimentary succession in the southern Appalachians that consists of the Nolichucky Shale, the Maynardville Formation, and the Copper Ridge Dolomite. The lower part of the succession contains Aphelaspis zone fauna (Early Steptoean). The extensively dolomitized and poorly fossiliferous nature of the upper part of the succession precludes any detailed biostratigraphic determinations. Correlation with similar positive carbon-isotope excursions in coeval successions elsewhere suggests that this excursion represents a perturbation in the global cycling of carbon. Comparison of excursions at different localities in North America provides a means for the application of …

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Uniqueness For A Boundary Identification Problem In Thermal Imaging, Kurt Bryan, Lester Caudill Nov 1998

Uniqueness For A Boundary Identification Problem In Thermal Imaging, Kurt Bryan, Lester Caudill

Department of Math & Statistics Faculty Publications

An inverse problem for an initial-boundary value problem is considered. The goal is to determine an unknown portion of the boundary of a region in ℝn from measurements of Cauchy data on a known portion of the boundary. The dynamics in the interior of the region are governed by a differential operator of parabolic type. Utilizing a unique continuation result for evolution operators, along with the method of eigenfunction expansions, it is shown that uniqueness holds for a large and physically reasonable class of Cauchy data pairs.

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Stability And Reconstruction For An Inverse Problem For The Heat Equation, Kurt Bryan, Lester Caudill Nov 1998

Stability And Reconstruction For An Inverse Problem For The Heat Equation, Kurt Bryan, Lester Caudill

Department of Math & Statistics Faculty Publications

We examine the inverse problem of determining the shape of some unknown portion of the boundary of a region Ω from measurements of the Cauchy data for solutions to the heat equation on Ω. By suitably linearizing the inverse problem we obtain uniqueness and continuous dependence results. We propose an algorithm for recovering estimates of the unknown portion of the surface and use the insight gained from a detailed analysis of the inverse problem to regularize the inversion. Several computational examples are presented.

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Center For Sustainable Agricultural Systems Newsletter, November/December 1998 Nov 1998

Center For Sustainable Agricultural Systems Newsletter, November/December 1998

Center for Sustainable Agricultural Systems: Newsletters (1993-2000)

Contents:

Grants to Teach Sustainable Agriculture

Spring CSAS Seminar Series: Re-Integrating Agriculture and Community in the Midwest

Highlights of Upcoming New Book: Under the Blade (Part 4)

Watershed Information Flows Along the Internet

Nordic Agroecology Program Begins August 1999

Beef Home Study Courses Begin Fifth Year

Two On-farm Assessment Tools

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Measuring The Deterrent Effect Of Punitive Damages, Theodore Eisenberg Nov 1998

Measuring The Deterrent Effect Of Punitive Damages, Theodore Eisenberg

Cornell Law Faculty Publications

Professor Viscusi's article differs from the dominant mode of law and economics scholarship on punitive damages. The usual punitive damages article contains purely theoretical considerations about when punitive damages are appropriate and about their optimal level; no effort is made to ascertain whether the existing pattern of punitive awards corresponds with the theory. This is part of a larger problem: the dearth of empirical evidence in law and economics scholarship. Viscusi, on the other hand, provides empirical tests of whether punitive damages accomplish their goals, and he makes creative use of publicly available data sources. For the goal of his …

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Inhibition Of The Aminopeptidase From Aeromonas Proteolytica By L-Leucinephosphonic Acid, A Transition State Analogue Of Peptide Hydrolysis, Brian Bennett, Richard C. Holz Nov 1998

Inhibition Of The Aminopeptidase From Aeromonas Proteolytica By L-Leucinephosphonic Acid, A Transition State Analogue Of Peptide Hydrolysis, Brian Bennett, Richard C. Holz

Physics Faculty Research and Publications

No abstract provided.

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Searches For The Neutral Higgs Bosons Of The Mssm In E+E- Collisions At Centre-Of-Mass Energies Of 181-184 Gev, Barate, R.; Et Al., M. Thulasidas Nov 1998

Searches For The Neutral Higgs Bosons Of The Mssm In E+E- Collisions At Centre-Of-Mass Energies Of 181-184 Gev, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

The data collected by ALEPH at LEP at centre-of-mass energies ranging from 181 to 184 GeV, corresponding to an integrated luminosity of 57 pb−1, are analysed to search for pair-produced neutral Higgs bosons h and A, in the bb̄bb̄ and τ+τ−bb̄ final states. Two events are found in the data with 2.5 expected from standard model processes. When combined with the lower energy data collected by ALEPH and with earlier reported searches for associated hZ production, these analyses are interpreted in the context of the minimal supersymmetric extension of the standard model (MSSM). For standard choices of MSSM parameter sets, …

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Information Coupling In Web Databases, Sourav S. Bhowmick, Wee-Keong Ng, Ee Peng Lim Nov 1998

Information Coupling In Web Databases, Sourav S. Bhowmick, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Web information coupling refers to an association of topically related web documents. This coupling is initiated explicitly by a user in a web warehouse specially designed for web information. Web information coupling provides the means to derive additional, useful information from the WWW. In this paper, we discuss and show how two web operators, i.e., global web coupling and local web coupling, are used to associate related web information from the WWW and also from multiple web tables in a web warehouse. This paper discusses various issues in web coupling such as coupling semantics, coupling-compability, and coupling evaluation.

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Interior Blowup In A Convection-Diffusion Equation, Christopher P. Grant Nov 1998

Interior Blowup In A Convection-Diffusion Equation, Christopher P. Grant

Faculty Publications

This paper addresses the qualitative behavior of a nonlinear convection-diffusion equation on a smooth bounded domain in Rn, in which the strength of the convection grows superlinearly as the density increases. While the initial-boundary value problem is guaranteed to have a local-in-time solution for smooth initial data, it is possible for this solution to be extinguished in nite time. We demonstrate that the way this may occur is through nite-time "blow up," i.e., the unboundedness of the solution in arbitrarily small neighborhoods of one or more points in the closure of the spatial domain. In special circumstances, such as the …

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Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz Nov 1998

Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz

Graduate School of Oceanography Faculty Publications

Practical autonomous robotic vehicles require dependable methods for accurately identifying course or roadway boundaries. The authors have developed a method to reliably extract the boundary line using simple dynamic thresholding, noise filtering, and blob removal. This article describes their efforts to apply this procedure in developing an autonomous vehicle.

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Essential Role Of Correlations In Governing Charge Transport In Disordered Organic Materials, Sergei V. Novikov, David H. Dunlap, Vasudev M. Kenkre, Paul Ernest Parris, Anatoly V. Vannikov Nov 1998

Essential Role Of Correlations In Governing Charge Transport In Disordered Organic Materials, Sergei V. Novikov, David H. Dunlap, Vasudev M. Kenkre, Paul Ernest Parris, Anatoly V. Vannikov

Physics Faculty Research & Creative Works

The transport of photoinjected charges in disordered organic films is often interpreted using a formula based on a Gaussian disorder model (GDM) that neglects spatial correlations due to charge-dipole interactions, even though such correlations have recently been shown to explain the universal electric field dependence observed in these systems. Based on extensive computer simulations of a 3D disorder model that includes such correlations, we present a new formula for analyzing experiments that accurately describes transport in these materials.

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Modelling Direct Episodic Recharge In The Western Australian Wheatbelt, F Lewis, Cooperative Research Centre For Catchment Hydrology (Australia) Nov 1998

Modelling Direct Episodic Recharge In The Western Australian Wheatbelt, F Lewis, Cooperative Research Centre For Catchment Hydrology (Australia)

Resource management technical reports

In agricultural regions of Western Australia, salinity is spreading. This is because the area taken up by groundwater discharge is increasing as a result of increased groundwater recharge following the replacement of native vegetation systems by annual crops and pasture species. Attempts to reduce groundwater recharge are now being made as it is hoped that this will decrease the rate of land salinisation. At several sites, average recharge rates have been estimated to be from 2% to 13% of the average annu ter hydrographs from the agricultural regions indicate that at some sites recharge does not occur as small amounts …

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Tga–Fti.R. Investigation Of The Thermal Degradation Of Nafion® And Nafion®/[Silicon Oxide]-Based Nanocomposites, Q. Deng, Charles Wilkie, R. B. Moore, Kenneth A. Mauritz Nov 1998

Tga–Fti.R. Investigation Of The Thermal Degradation Of Nafion® And Nafion®/[Silicon Oxide]-Based Nanocomposites, Q. Deng, Charles Wilkie, R. B. Moore, Kenneth A. Mauritz

Chemistry Faculty Research and Publications

The integrated TGA–FTi.r. technique probed the thermal degradation of: (1) a Nafion®–H+ membrane; (2) this membrane as modified by incorporation of a SiO2[1-x/4] (OH)x phase via in situ sol–gel reactions for tetraethoxysilane; and (3) this modified membrane as further modified, organically, via post-reaction with diethoxydimethylsilane. Gravimetric loss is multistep for (1) and (2), but occurs in a single step for (3) which has the greatest thermal degradative stability. The considerable inhibition of SO2 evolution for (2) and (3) is rationalized in terms of side-chains that are immobilized within silicon oxide cages …

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A Global Object Model For Accommodating Instance Heterogeneities, Ee Peng Lim, Roger Hsiang-Li Chiang Nov 1998

A Global Object Model For Accommodating Instance Heterogeneities, Ee Peng Lim, Roger Hsiang-Li Chiang

Research Collection School Of Computing and Information Systems

To completely address database integration problems in the context of multidatabase [10] and data warehousing systems, one has to examine various integration and query requirements. Due to various reasons such as poor data quality in local databases, ongoing local database updates, and instance heterogeneities, some instance differences have to be accommodated by the integrated databases. We have therefore proposed a new object-oriented global data model, called OORA, that can accommodate attribute and relationship instance heterogeneities in the integrated database. In addition, the OORA model has been designed to allow database integrators and end users to query both the local and …

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A Framework For Sharing Handwritten Notes, Richard C. Davis, James Lin, Jason A. Brotherton, James A. Landay, Morgan N. Price, Bill N. Schilit Nov 1998

A Framework For Sharing Handwritten Notes, Richard C. Davis, James Lin, Jason A. Brotherton, James A. Landay, Morgan N. Price, Bill N. Schilit

Research Collection School Of Computing and Information Systems

NotePals is an ink-based, collaborative note taking application that runs on personal digital assistants (PDAs). Meeting participants write notes in their own handwriting on a PDA. These notes are shared with other participants by synchronizing later with a shared note repository that can be viewed using a desktop-based web browser. NotePals is distinguished by its lightweight process, interface, and hardware. This demonstration illustrates the design of two different NotePals clients and our web-based note browser.

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Notepals: Sharing And Synchronizing Handwritten Notes With Multimedia Documents, James A. Landay, Richard C. Davis, Victor Chen, Jonathan Huang, Rebecca B. Lee, Francis Li, James Lin, Charles B. Morrey, Ben Schleimer Nov 1998

Notepals: Sharing And Synchronizing Handwritten Notes With Multimedia Documents, James A. Landay, Richard C. Davis, Victor Chen, Jonathan Huang, Rebecca B. Lee, Francis Li, James Lin, Charles B. Morrey, Ben Schleimer

Research Collection School Of Computing and Information Systems

NotePals is an ink-based, collaborative note taking application that runs on personal digital assistants (PDAs). Meeting participants write notes in their own handwriting on a PDA. These notes are shared with other participants by synchronizing later with a shared note repository that can be viewed using a desktop-based web browser. NotePals is distinguished by its lightweight process, interface, and hardware. This demonstration illustrates the design of two different NotePals clients and our web-based note browser.

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Laser In-Situ Scattering And Transmissometer (Lisst) Observations In Support Of The Sensor Insertion System Duck, Nc October, 1997, Grace M. Massey, Carl T. Friedrichs Nov 1998

Laser In-Situ Scattering And Transmissometer (Lisst) Observations In Support Of The Sensor Insertion System Duck, Nc October, 1997, Grace M. Massey, Carl T. Friedrichs

Reports

The objective of this portion of the study was to collect LIS ST time series at times corresponding to collection of pumped samples of suspended sediment across the width of the surf zone during a major field experiment called SandyDuck '97. The pumped samples were analyzed for total percent sand (>60 micron), total percent mud (0.8 - 60 micron), organic content and sand size distribution. The LISST measures the particle size distribution from 5-500 microns. The purpose was to provide a high quality data set of pumped samples with which to later test the sensitivity of indirect measurements of …

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Public Policy: Integrated Approaches To Environmental Policy, Karla S. Havens, Virginia Institute Of Marine Science, Wetlands Program Nov 1998

Public Policy: Integrated Approaches To Environmental Policy, Karla S. Havens, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.

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Web Bags: Are They Useful In A Web Warehouse?, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim Nov 1998

Web Bags: Are They Useful In A Web Warehouse?, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Sets and bags are closely related structures. A bag is different from a set in that it is sensitive to the number of times an element occurs while a set is not. In this paper, we introduce the concept of web bag in a web warehouse as a part of our Web Information Coupling System(WICS). Informally, a web bag is a web table which allows multiple occurrences of identical web tuples. Web bag helps to discover useful knowledge from a web table such as visible documents (or web sites), luminous documents and luminous paths. We formally discuss the semantics and …

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Web Warehousing System: Design And Issues, Wee-Keong Ng, Ee Peng Lim, Sourav S. Bhowmick, Sanjay Kumar Madria Nov 1998

Web Warehousing System: Design And Issues, Wee-Keong Ng, Ee Peng Lim, Sourav S. Bhowmick, Sanjay Kumar Madria

Research Collection School Of Computing and Information Systems

The World Wide Web is a distributed global information resource. It contains a large amount of information that have been placed on the web independently by different organizations and thus, related information may appear across different web sites. To manage and access heterogeneous information on WWW, we have started a project of building a web warehouse, called Whoweda (Warehouse of Web Data). Currently, our work on building a web warehousing system has focused on building a data model and designing a web algebra. In this paper, we discuss design and research issues in a web warehousing system. The issues include …

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Accurate Classification Of Juvenile Weakfish Cynoscion Regalis To Estuarine Nursery Areas Based On Chemical Signatures In Otoliths, Simon R. Thorrold, Cynthia M. Jones, Peter K. Swart, Timothy E. Targett Nov 1998

Accurate Classification Of Juvenile Weakfish Cynoscion Regalis To Estuarine Nursery Areas Based On Chemical Signatures In Otoliths, Simon R. Thorrold, Cynthia M. Jones, Peter K. Swart, Timothy E. Targett

OES Faculty Publications

We investigated the ability of trace element and isotopic signatures in otoliths to record the nursery areas of juvenile (young-of-the-year) weakfish Cynoscion regalis from the east coast of the USA. Juvenile C. regalis were captured with otter trawls at multiple sites in Doboy Sound (Georgia), Pamlico Sound (North Carolina), Chesapeake Bay (Virginia), Delaware Bay (Delaware) and Peconic Bay (New York), from July to September 1996. One sagittal otolith from each specimen was assayed for Mg/Ca, Mn/Ca, Sr/Ca and Ba/Ca ratios using inductively coupled plasma mass spectrometry (ICP-MS), while delta 13 C and delta 18 O values from the other sagittal …

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A Photometric And Kinematic Study Of Awm 7, Daniel M. Koranyi, Margaret Geller, Joseph J. Mohr, Gary Wegner Nov 1998

A Photometric And Kinematic Study Of Awm 7, Daniel M. Koranyi, Margaret Geller, Joseph J. Mohr, Gary Wegner

Dartmouth Scholarship

We have measured redshifts and Kron-Cousins R-band magnitudes for a sample of galaxies in the poor cluster AWM 7. We have measured redshifts for 172 galaxies; 106 of these are cluster members. We determine the luminosity function (LF) from a photometric survey of the central 1.2 × 1.2 h-1 Mpc. The LF has a bump at the bright end and a faint-end slope of α = -1.37 ± 0.16, populated almost exclusively by absorption-line galaxies. The cluster velocity dispersion is lower in the core (~530 km s-1) than at the outskirts (~680 km s-1), …

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A Symposium On 'Controls On Soil Resoration: Implications For Climate Change'; October 27-28, 1997; Anaheim, Ca, Lindsey E. Rustad Oct 1998

A Symposium On 'Controls On Soil Resoration: Implications For Climate Change'; October 27-28, 1997; Anaheim, Ca, Lindsey E. Rustad

University of Maine Office of Research Administration: Grant Reports

The potential disruption of global C cycles by human activity in both developed and developing counties is one of the key environmental issues facing human populations as we move into the 21st century. Deforestation of tropical rainforests, changes in land-use, and continued burning of fossil fuels have resulted in an unprecedented increase in atmospheric CO2 concentrations over the last half century. This has raised concerns about potential global warming and climate change, and consequences for further disruptions of the global C cycle. Soil respiration, which represents the combined respiration of roots and soil micro- and macro- biota, represents one of …

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Structural Biology Metaphors Applied To The Design Of A Distributed Object System, Ladislau Bölöni, Ruibing Hao, Kyungkoo Jun, Dan C. Marinescu Oct 1998

Structural Biology Metaphors Applied To The Design Of A Distributed Object System, Ladislau Bölöni, Ruibing Hao, Kyungkoo Jun, Dan C. Marinescu

Department of Computer Science Technical Reports

No abstract provided.

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Contract Manager Anywhere And Internet-Enabled Database Application, Yao-Jen Chang Oct 1998

Contract Manager Anywhere And Internet-Enabled Database Application, Yao-Jen Chang

FIU Electronic Theses and Dissertations

This thesis describes the design and implementation of an Internet-enabled database application which uses ASP (Active Server Pages) and other related knowledge such as ADO (ActiveX Data Object), ODBC (Open DataBase Connectivity) and OLE-DB (Object Linking and Embed-DataBase). Because it is an Internet-enabled application, the subject of "Security" was also studied by implementing ASP technology. The database was created using Microsoft Access 97 and the web interface was built using HTML, VBScript and JavaScript. This system will be fully functioning at the Florida Department of Education (FLDOE) site and will enable remote access to allow users to monitor hundreds of …

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State To State He-Co Rotationally Inelastic Scattering, Stiliana Antonova, Ao Lin, Antonis P. Tsakotellis, George C. Mcbane Oct 1998

State To State He-Co Rotationally Inelastic Scattering, Stiliana Antonova, Ao Lin, Antonis P. Tsakotellis, George C. Mcbane

Peer Reviewed Articles

Relative integral cross sections for rotational excitation of CO in collisions with He were measured at energies of 72 and 89 meV. The cross sections are sensitive to anisotrophy in the repulsive wall of the He-CO interaction. The experiments were done in crossed molecular beams with resonance enhanced multiphoton ionization detection. The observed cross sections display interference structure at low Δj, despite the average over the initial CO rotational distribution. At higher Δj, the cross sections decrease smoothly. The results are compared with cross sections calculated from two high quality potential energy surfaces for the He-CO …

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A Continuum Analysis Of The Chemotactic Signal Seen By Dictyostelium Discoideum, J. C. Dallon, H. G. Othmer Oct 1998

A Continuum Analysis Of The Chemotactic Signal Seen By Dictyostelium Discoideum, J. C. Dallon, H. G. Othmer

Faculty Publications

We develop a mathematical model of cell-to-cell-signalling in Dictyostelium discoideum that predicts the cAMP signal seen by individual cells in early aggregation. The model employs two cells on a plane and is designed to predict the space-time characteristics of both the extracellular cAMP signal seen by one cell when a nearby cell relays, and the intracellular cAMP response produced by the stimulus in the receiving cell. The effect of membrane bound phosphodiesterase is studied and it is shown that cells can orient effectively even in its absence. Our results give a detailed picture of how the spatio-temporal characteristics of the …

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Field Trip Guide: Illinois River Summary, National Poultry Water Management Symposium, Kenneth F. Steele Oct 1998

Field Trip Guide: Illinois River Summary, National Poultry Water Management Symposium, Kenneth F. Steele

Technical Reports

No abstract provided.

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Charge Density Wave Caused By Reducing Thse3 By One Electron. Superstructure And Short-Range Order In Ath2se6 (A = K, Rb) Studied By X-Ray Diffraction, Electron Diffraction, And Diffuse Scattering, Kyoung-Shin Choi, Rhonda Patschke, Simon Billinge, Mark Waner, Marcos Dantus, Mercouri Kanatzidis Oct 1998

Charge Density Wave Caused By Reducing Thse3 By One Electron. Superstructure And Short-Range Order In Ath2se6 (A = K, Rb) Studied By X-Ray Diffraction, Electron Diffraction, And Diffuse Scattering, Kyoung-Shin Choi, Rhonda Patschke, Simon Billinge, Mark Waner, Marcos Dantus, Mercouri Kanatzidis

Mark J. Waner

Charge Density Wave Caused by Reducing ThSe3 by One Electron. Superstructure and Short-Range Order in ATh2Se6 (A = K, Rb) Studied by X-ray Diffraction, Electron Diffraction, and Diffuse Scattering

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Effects Of Production And Oxidation Processes On Methane Emissions From Rice Fields, M. Khalil, R. A. Rasmussen, Martha J. Shearer Oct 1998

Effects Of Production And Oxidation Processes On Methane Emissions From Rice Fields, M. Khalil, R. A. Rasmussen, Martha J. Shearer

Physics Faculty Publications and Presentations

The emission of methane from rice fields is the difference between the amount produced in the anaerobic zone below the soil and the amount oxidized in the root zone. Plants can also contribute to methane production by exuding organic compounds that may be utilized by methanogenic bacteria. We measured methane emissions from rice fields at Tu Zu in China between 1988 and 1994, which gave average emissions of about 30 mg m⁻² h⁻¹. We estimate that 45-60% of the methane produced was oxidized before reaching the atmosphere; and root exudates may have contributed of the order of 10% of the …

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