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2001

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Articles 31 - 60 of 3030

Full-Text Articles in Physical Sciences and Mathematics

Three Unique Coordination Geometries Involving 1,2-Dimethoxy-4,5-Bis(2-Pyridylethynyl)Benzene, Jeffrey E. Fiscus, Sandra Shotwell, Ralph C. Layland, Mark D. Smith, Hans Conrad Zur Loye, Uwe H. F. Bunz Dec 2001

Three Unique Coordination Geometries Involving 1,2-Dimethoxy-4,5-Bis(2-Pyridylethynyl)Benzene, Jeffrey E. Fiscus, Sandra Shotwell, Ralph C. Layland, Mark D. Smith, Hans Conrad Zur Loye, Uwe H. F. Bunz

Faculty Publications

Reaction of the new ligand 1,2-dimethoxy-4,5-bis(2-pyridylethynyl) benzene with different metal centers under similar reaction conditions led to three distinct structure formation processes: molecular ring closure, dimerization, and polymer formation.


Night Out Itinerary Creator, Jennifer Hood Dec 2001

Night Out Itinerary Creator, Jennifer Hood

Honors Capstone Projects and Theses

No abstract provided.


Search For New Physics Using Quaero: A General Interface To D0 Event Data, V. M. Abazov, Gregory R. Snow, D0 Collaboration Dec 2001

Search For New Physics Using Quaero: A General Interface To D0 Event Data, V. M. Abazov, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

We describe QUAERO, a method that (i) enables the automatic optimization of searches for physics beyond the standard model, and (ii) provides a mechanism for making high energy collider data generally available. We apply QUAERO to searches for standard model WW, ZZ , and tt̅ production, to searches for these objects produced through a new heavy resonance, and to the first direct search for W′→ WZ. Through this interface, we make three data sets collected by the D0 experiment at √s =1.8 TeV publicly available.


Reduced Order Modeling For High Speed Flows With Moving Shocks, David J. Lucia Dec 2001

Reduced Order Modeling For High Speed Flows With Moving Shocks, David J. Lucia

Theses and Dissertations

The use of Proper Orthogonal Decomposition (POD) for reduced order modeling (ROM) of fluid problems is extended to high-speed compressible fluid flows. The challenge in using POD for high-speed flows is presented by the presence of moving discontinuities in the flow field. To overcome these difficulties, a domain decomposition approach is developed that isolates the region containing the moving shock wave for special treatment. The domain decomposition implementation produces internal boundaries between the various domain sections. The domains are linked using optimization-based solvers which employ constraints to ensure smoothness in overlapping portions of the internal boundary. This approach is applied …


Search For Quark-Lepton Compositeness And A Heavy W′ Boson Using The Eν Channel In Pp̅ Collisions At √S = 1.8 Tev, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Dec 2001

Search For Quark-Lepton Compositeness And A Heavy W′ Boson Using The Eν Channel In Pp̅ Collisions At √S = 1.8 Tev, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We present searches for quark-lepton compositeness and a heavy W′ boson at high electron-neutrino transverse mass. We use ~110 pb-1 of data collected in pp̅ collisions at √s= 1.8 TeV by the CDF Collaboration during 1992–1995. The data are consistent with standard model expectations. Limits are set on the quark-lepton compositeness scale Λ, the ratio of partial cross sections σ (W′ → eν)/ σ (W → eν), and the mass of a W′ boson with standard model couplings. We exclude Λ< 2.81 TeV and a W′ boson with mass below 754 GeV/c2 at the 95% …


The Biosynthetic Gene Cluster For The Anticancer Drug Bleomycin From Streptomyces Verticillus Atcc15003 As A Model For Hybrid Peptide–Polyketide Natural Product Biosynthesis, B. Shen, Liangcheng Du, C. Sanchez, D. J. Edwards, M. Chen, J. M. Murrell Dec 2001

The Biosynthetic Gene Cluster For The Anticancer Drug Bleomycin From Streptomyces Verticillus Atcc15003 As A Model For Hybrid Peptide–Polyketide Natural Product Biosynthesis, B. Shen, Liangcheng Du, C. Sanchez, D. J. Edwards, M. Chen, J. M. Murrell

Liangcheng Du Publications

The hybrid peptide–polyketide backbone of bleomycin (BLM) is assembled by the BLM megasynthetase that consists of both nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) modules. BlmIX/BlmVIII/BlmVII constitute a natural hybrid NRPS/PKS/NRPS system, serving as a model for both hybrid NRPS/PKS and PKS/NRPS systems. Sequence analysis and functional comparison of domains and modules of BlmIX/BlmVIII/BlmVII with those of nonhybrid NRPS and PKS systems suggest that (1) the same catalytic sites appear to be conserved in both hybrid NRPS–PKS and nonhybrid NRPS or PKS systems, with the exception of the KS domains in the hybrid NRPS/PKS systems that are unique; (2) …


Water Current, Volume 33, No. 6. December 2001 Dec 2001

Water Current, Volume 33, No. 6. December 2001

Water Current Newsletter

• “Daisy Well System” Promising Way for Small Communities to Fight Nitrates by Steve Ress

• From the Director

• Meet the Faculty

• Water and the NRCS…All Encompassing Topics by Steve Chick

• Variety and Current Issues Punctuate Spring Water and Natural Resources Seminar by Steve Ress

• Integrated Water Management Options in the Nebraska Ground Water Management & Protection Act by J. David Aiken

• Arkansas Researchers Study Water Quality on Nebraska Tribal Lands by Ralph Davis and Shelley McGinnis

• Platte River Policy Preferences by Raymond J. Supalla

• Water News Briefs


Diagenesis Of Upper Cambrian Mount Simon Sandstone In The Illinois Basin - Microscale Investigation Of Basinal Fluid Migration And Mass Transfer, Zhensheng Chen Dec 2001

Diagenesis Of Upper Cambrian Mount Simon Sandstone In The Illinois Basin - Microscale Investigation Of Basinal Fluid Migration And Mass Transfer, Zhensheng Chen

Doctoral Dissertations

A series of investigations were conducted to evaluate microscale evidence for basinal fluid migration in the Illinois basin during diagenesis of the Upper Cambrian Mount Simon Sandstone. Samples were examined using transmitted light and cathodoluminescence (CL) petrography, fluid inclusion analysis, and Secondary Ion Mass Spectrometry (SIMS) analysis of 18O/16O ratios and trace element compositions. Preliminary investigation of in situ laser ablation 40Ar-39Ar age dating techniques on authigenic K-feldspar over growths was also completed.

Two major generations of quartz overgrowths are observed, on the basis of transmitted light and CL petrography and fluid inclusion studies. …


Two Body Dirac Equations And Nucleon Nucleon Scattering Phase Shift Analysis, Bin Liu Dec 2001

Two Body Dirac Equations And Nucleon Nucleon Scattering Phase Shift Analysis, Bin Liu

Doctoral Dissertations

In this dissertation, the nucleon-nucleon interaction is investigated by using the meson exchange model and the two body Dirac equations of constraint dynamics. This approach to the two body problem has been successfully tested for QED and QCD relativistic bound states. An important question we wish to address is whether or not this approach is also valid in the two body nucleon-nucleon scattering problem. This test involves a number of related problems.

First we must reduce our two body Dirac equations exactly to a Schr¨odinger-like equation. This can be done without making any assumptions or approximations and unlike other relativistic …


Large Sets Of Zero Analytic Capacity, John Garnett, Stan T. Yoshinobu Dec 2001

Large Sets Of Zero Analytic Capacity, John Garnett, Stan T. Yoshinobu

Mathematics

We prove that certain Cantor sets with non-sigma-finite one-dimensional Hausdorff measure have zero analytic capacity.


Methanesulfonate In The Firn Of King George Island, Antarctica, Jiankang Han, Zichu Xie, Xinping Zhang, Dongsheng Dai, Paul Andrew Mayewski, M. S. Twickler Dec 2001

Methanesulfonate In The Firn Of King George Island, Antarctica, Jiankang Han, Zichu Xie, Xinping Zhang, Dongsheng Dai, Paul Andrew Mayewski, M. S. Twickler

Earth Science Faculty Scholarship

Methanesulfonate was investigated as a potential contributor to the sulfur budget, based on analysis of a firn core from Collins Ice Cap, King George Island, Antarctica (62°10' S, 58°50' W). The anion was found to be present at a mean concentration of 0.17 μeq L-1, with a maximum of 0.73 μeq L-1. Dating based on the δ18O profile suggests that the principal peaks of methanesulfonate are associated with snow deposited in summer and autumn. A careful examination of MSA, SO42-and nssSO42- profiles indicates that two of the three peaks …


Discrete Maximum Principle For Nonsmooth Optimal Control Problems With Delays, Boris S. Mordukhovich, Ilya Shvartsman Dec 2001

Discrete Maximum Principle For Nonsmooth Optimal Control Problems With Delays, Boris S. Mordukhovich, Ilya Shvartsman

Mathematics Research Reports

We consider optimal control problems for discrete-time systems with delays. The main goal is to derive necessary optimality conditions of the discrete maximum principle type in the case of nonsmooth minimizing functions. We obtain two independent forms of the discrete maximum principle with transversality conditions described in terms of subdifferentials and superdifferentials, respectively. The superdifferential form is new even for non-delayed systems and may be essentially stronger than a more conventional subdifferential form in some situations.


The Cataclysmic Variable Cw 1045+525: A Secondary-Dominated Dwarf Nova?, C. Tappert, J. R. Thorstensen, W. H. Fenton, N. Bennert, L. Schmidtobreick, A. Bianchini Dec 2001

The Cataclysmic Variable Cw 1045+525: A Secondary-Dominated Dwarf Nova?, C. Tappert, J. R. Thorstensen, W. H. Fenton, N. Bennert, L. Schmidtobreick, A. Bianchini

Physics

We present spectroscopic and photometric observations of the cataclysmic variable CW 1045+525. Both the optical spectrum and the photometric lightcurve show a strong contribution of a K5V-M0V secondary. We derive an orbital period d by measuring the radial velocities of the absorption lines of the secondary. The period and spectral type of the secondary suggest a distance of 350-700 pc. There is evidence for additional sources of line- and continuum emission, but no direct evidence of an accretion disc. We discuss several scenarios for the nature of CW 1045+525 on the basis of our results, finding a dwarf nova classification …


The Study Of Biological Membranes Using The Atomic Force Microscope, Brandy L. Perkins Dec 2001

The Study Of Biological Membranes Using The Atomic Force Microscope, Brandy L. Perkins

Electronic Dissertations and Theses

In the past research, when a carbon nanotube enhanced cantilever was probed along a living cell membrane, carboxylic acid groups located at the tips of the nanotubes would interact with various groups on the surface of the membrane causing it to rupture. A method to re-derivatize the tips of the nanotubes through covalent bonding by allowing the amine groups to attach to the carboxylic acid groups was developed. This chemical change perhaps will allow one to probe a cell surface without rupturing it. Successful nanotube derivatization will eventually lead to a map of the surface of living cell membranes and …


Phytoremediation Of Lead By Chinese Tallow (Sapium Sebiferum) Plant, Oluwaseumi A. Odebunmi Dec 2001

Phytoremediation Of Lead By Chinese Tallow (Sapium Sebiferum) Plant, Oluwaseumi A. Odebunmi

Electronic Dissertations and Theses

Over the past several decades, health and environmental risks of pollution have become apparent. As a result, environmental regulations have been created to remediate areas where environmental contamination is tremendous, therefore, a low-cost alternative to the already existing technology is needed. Using plants to eliminate hazardous organic compounds from contaminated soils has been proposed as an efficient means of remediation. Phytoremediation is the direct use of living green plants to remediate soil, sludge, sediments and ground water contaminated with toxic compounds. The four processes of phytoremediation are rhizofiltration, phytoextraction, phytostabilization and phytodegradation. As they 'grow and develop, plants will use …


Anatomy And Three-Dimensional Reconstructions Of The Brain Of A Bottlenose Dolphin (Tursiops Truncatus) From Magnetic Resonance Images, Lori Marino, Keith D. Sudheimer, Timothy L. Murphy, Kristina K. Davis, D. Ann Pabst, William A. Mclellan, James K. Rilling, John I. Johnson Dec 2001

Anatomy And Three-Dimensional Reconstructions Of The Brain Of A Bottlenose Dolphin (Tursiops Truncatus) From Magnetic Resonance Images, Lori Marino, Keith D. Sudheimer, Timothy L. Murphy, Kristina K. Davis, D. Ann Pabst, William A. Mclellan, James K. Rilling, John I. Johnson

Veterinary Science and Medicine Collection

Cetacean (dolphin, whale, and porpoise) brains are among the least studied mammalian brains because of the formidability of collecting and histologically preparing such relatively rare and large specimens. Magnetic resonance imaging offers a means of observing the internal structure of the brain when traditional histological procedures are not practical. Furthermore, internal structures can be analyzed in their precise anatomic positions, which is difficult to accomplish after the spatial distortions often accompanying histological processing. In this study, images of the brain of an adult bottlenose dolphin, Tursiops truncatus, were scanned in the coronal plane at 148 antero-posterior levels. From these scans …


Geosciences Newsletter - 2001, Department Of Geosciences Dec 2001

Geosciences Newsletter - 2001, Department Of Geosciences

Geological and Environmental Sciences News

Vol.1, No. 26

  • Faculty News
  • Core Lab
  • Groundwater Education of Michigan (GEM) Center
  • Graduate Student News
  • Alumni News
  • Advisory Council News
  • Donations


Atomic And Electronic Structure Of Co/Srtio3/Co Tunnel Junctions, Ivan I. Oleinik, Evgeny Y. Tsymbal, David G. Pettifor Dec 2001

Atomic And Electronic Structure Of Co/Srtio3/Co Tunnel Junctions, Ivan I. Oleinik, Evgeny Y. Tsymbal, David G. Pettifor

Evgeny Tsymbal Publications

First-principles density-functional calculations of the atomic and electronic structure of Co/SrTiO3 /Co (001) magnetic tunnel junctions (MTJ’s) are performed. Different interface terminations are considered and the most stable structure with the TiO2 termination is identified based on energetics of adhesion. The calculated electronic structure of the TiO2-terminated MTJ shows an exchange coupling between the interface Co and Ti atoms mediated by oxygen. This coupling induces a magnetic moment of 0.25 µB on the interface Ti atom, which is aligned antiparallel to the magnetic moment of the Co layer. We argue that this might cause an …


Active Information Retrieval, Tommi Jaakkola, Hava Siegelmann Dec 2001

Active Information Retrieval, Tommi Jaakkola, Hava Siegelmann

Hava Siegelmann

In classical large information retrieval systems, the system responds to a user initiated query with a list of results ranked by relevance. The users may further refine their query as needed. This process may result in a lengthy correspondence without conclusion. We propose an alternative active learning approach, where the system responds to the initial user’s query by successively probing the user for distinctions at multiple levels of abstraction. The system’s initiated queries are optimized for speedy recovery and the user is permitted to respond with multiple selections or may reject the query. The information is in each case unambiguously …


An Investigation Of The Rank Transformation In Multple Regression, Todd C. Headrick, Ourania Rotou Dec 2001

An Investigation Of The Rank Transformation In Multple Regression, Todd C. Headrick, Ourania Rotou

Todd Christopher Headrick

Real world data often fail to meet the underlying assumptions of normal statistical theory. The rank transformation (RT) procedure is recommended and used in the context of multiple regression analysis when the assumption of normality is violated. There is no general supporting theory of the RT. In view of this, the current study examined the Type I error and power properties of the RT in terms of multiple regression. The investigation included both additive and nonadditive models. Results indicated that there were severely inflated Type I error rates associated with the RT procedure under both normal and nonnormal distributions (e.g., …


Institutsdagen At The Royal Institute Of Technology, Stockholm, Sweden, May 3, 2000, Otto Vogl, Ann Christine Albertsson Dec 2001

Institutsdagen At The Royal Institute Of Technology, Stockholm, Sweden, May 3, 2000, Otto Vogl, Ann Christine Albertsson

Otto Vogl

No abstract provided.


Bulletin No. 37: Living Resources And Habitats Of The Lower Connecticut River, Glenn D. Dreyer, Marcianna Caplis Dec 2001

Bulletin No. 37: Living Resources And Habitats Of The Lower Connecticut River, Glenn D. Dreyer, Marcianna Caplis

Bulletins

No abstract provided.


Periodic Points Of The Family Of Tent Maps, Julio R. Hasfura-Buenaga, Phillip Lynch Dec 2001

Periodic Points Of The Family Of Tent Maps, Julio R. Hasfura-Buenaga, Phillip Lynch

Mathematics Faculty Research

No abstract provided.


Absorption Of Microwaves In La1Àxsrxmno3 Manganese Powders Over A Wide Bandwidth, G. Li, G. G. Hu, H. D. Zhou, Xiaojuan Fan, X. G. Li Dec 2001

Absorption Of Microwaves In La1Àxsrxmno3 Manganese Powders Over A Wide Bandwidth, G. Li, G. G. Hu, H. D. Zhou, Xiaojuan Fan, X. G. Li

Physics Faculty Research

We present the frequency dependence of microwave-absorbing properties of La1-xSrxMnO3 (x=0.4, 0.5, 0.6, and 0.7) powders at room temperature. The absorbing properties change gradually with x in the frequency range of 8–12 GHz. The optimal absorption can be achieved for a x=0.4 sample and its microwave loss peak value is about 25 dB. Further experimental results show that the absorption can be attributed to magnetic and dielectric losses and the microwave loss peak corresponds to the maximum dielectric loss tangent tan δe near 10.5 GHz. Furthermore, the absorbing properties of the oxides mixed with …


The Role Of Environmental Analogs In Identifying Potentially Invasive Woody Plants In Iowa, Mark P. Widrlechner Dec 2001

The Role Of Environmental Analogs In Identifying Potentially Invasive Woody Plants In Iowa, Mark P. Widrlechner

Journal of the Iowa Academy of Science: JIAS

Americans cultivate a large and diverse range of introduced woody plants as important sources of food and forest products, as well as for urban horticulture, amenity and wildlife plantings, and windbreaks. A small number of these species have become serious pests, disrupting well-established native plant communities or functioning as range and agricultural weeds. More of these species are not serious pests today, but have escaped cultivation and serve as potential sources of future outbreaks. Two other sources of potentially invasive woody plants are found among species that are not or are only rarely cultivated, about which we often know little …


Chromospherically Active Stars. Xx. The Giant Single-Lined Binary Hd 161570, Francis C. Fekel, Gregory W. Henry, Stephen M. Henry Dec 2001

Chromospherically Active Stars. Xx. The Giant Single-Lined Binary Hd 161570, Francis C. Fekel, Gregory W. Henry, Stephen M. Henry

Information Systems and Engineering Management Research Publications

Spectroscopy of HD 161570 shows it to be a single-lined spectroscopic binary with a period of 45.623 days and a nearly circular orbit. The primary star has spectral type G7 III, and the secondary is most likely a G or K dwarf. A high-resolution spectrum of the 3950 Å region confirms that the primary has Ca II H and K emission lines. The logarithm of the giant's lithium abundance is less than 0.9, indicating that it is not lithium-rich. From photometric observations covering six seasons, we detected periodic short-term light variability with an amplitude ranging from 0.02 to 0.04 mag. …


Harmonising Chart And Navigation-Related Information On Ecdis, Lee Alexander Dec 2001

Harmonising Chart And Navigation-Related Information On Ecdis, Lee Alexander

Center for Coastal and Ocean Mapping

ECDIS is a real-time navigation system that integrates a variety of chart and navigation-related information. More than simply a replacement for a paper nautical chart, ECDIS is capable of continuously determining a vessel's position in relation to land, charted objects, aids-to-navigation, and unseen hazards. Increasingly, ECDIS is being used for both navigation and collision-avoidance tasks. There is growing concern about the display of ever-increasing amounts of both chart and navigation-related information. When it comes to using ECDIS, displaying more information is not necessarily better. Too much information (i.e., clutter) may only lead to confusion. In this regard, there is need …


Plant Acoustic Density Profile Model Of Ctfm Ultrasonic Sensing, Phillip J. Mckerrow, N. Harper Dec 2001

Plant Acoustic Density Profile Model Of Ctfm Ultrasonic Sensing, Phillip J. Mckerrow, N. Harper

Faculty of Informatics - Papers (Archive)

Many applications require the sensing of plants. When an ultrasonic sensor insonifies a plant, the resultant echo is the superposition of the echoes from the leaves. As a result, the echo contains information about the geometric structure of the foliage. In this paper, we present a model of sensing that facilitates the extraction of geometric features from the echo for plant classification, recognition and discrimination. We model the echo from a CTFM ultrasonic sensor with the acoustic density profile model. Then, we identify a set of features that represent plant geometric characteristics and use these to perform an inverse transform …


Fuzzy Clustering Evaluation Of Time-Frequency Distribution (Tfd) Schemes For Audio Stream Segregation, M. A. Jackson, I. Burnett Dec 2001

Fuzzy Clustering Evaluation Of Time-Frequency Distribution (Tfd) Schemes For Audio Stream Segregation, M. A. Jackson, I. Burnett

Faculty of Informatics - Papers (Archive)

Audio stream segregation is a task performed constantly by the human auditory system, yet is difficult to reproduce with a computer. The research detailed in this paper looks at performing just one method of stream segregation - the temporal coherence boundary - using a fuzzy clustering system. The main focus of the paper is on examining the effectiveness of several time-frequency distributions as the feature vectors for the system. Three time-frequency distributions are examined and their effectiveness evaluated in terms of correct separation and computational complexity. The main evaluation compares the popular gamma-tone filter bank with the MPEG-7 audio spectrum …


On Detecting Service Violations And Bandwidth Theft In Qos Network Domains, Ahsan Habib, Sonia Fahmy, Srinivas R. Avasarala, Venkatesh Prabhakar, Bharat Bhargava Dec 2001

On Detecting Service Violations And Bandwidth Theft In Qos Network Domains, Ahsan Habib, Sonia Fahmy, Srinivas R. Avasarala, Venkatesh Prabhakar, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.