Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

2004

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 3121 - 3150 of 4447

Full-Text Articles in Physical Sciences and Mathematics

Leaf Litter Processing By Macrodetritivores In Natural And Restored Neotropical Mangrove Forests, Gary Eugene Raulerson Jan 2004

Leaf Litter Processing By Macrodetritivores In Natural And Restored Neotropical Mangrove Forests, Gary Eugene Raulerson

LSU Doctoral Dissertations

Knowledge of mangrove litter dynamics is crucial to an understanding of the energetic links between mangrove ecosystems and nearby estuaries and coastal waters. Previous research into the role played by macrodetritivores in Neotropical mangrove litter processing has been contradictory. This study used leaf tethering to examine the effects of macrodetritivores on initial rates of mangrove litter degradation in South Florida, USA. Leaf litter dynamics experiments were run in both natural and restored mangrove forests to assess functionality of the restoration projects. Although less important than in some other parts of the world (e.g., the Indo-Pacific), macrodetritivores played a significant role …


Address Optimizations For Embedded Processors, Sai Pinnepalli Jan 2004

Address Optimizations For Embedded Processors, Sai Pinnepalli

LSU Doctoral Dissertations

Embedded processors that are common in electronic devices perform a limited set of tasks compared to general-purpose processor systems. They have limited resources which have to be efficiently used. Optimal utilization of program memory needs a reduction in code size which can be achieved by eliminating unnecessary address computations i.e., generate optimal offset assignment that utilizes built-in addressing modes. Single offset assignment (SOA) solutions, used for processors with one address register; start with the access sequence of variables to determine the optimal assignment. This research uses the basic block to commutatively transform statements to alter the access sequence. Edges in …


Spectroscopic And Synthetic Studies Relating To A Dirhodium Hydroformylation Catalyst, Petia Gueorguieva Gueorguieva Jan 2004

Spectroscopic And Synthetic Studies Relating To A Dirhodium Hydroformylation Catalyst, Petia Gueorguieva Gueorguieva

LSU Doctoral Dissertations

The main goal of this dissertation research was to further study and characterize our bimetallic hydroformylation catalyst, rac-[Rh2(nbd)2(et,ph-P4)](BF4)2, and to fully identify the catalytically inactive mono- and dirhodium complexes formed upon fragmentation of the catalyst under hydroformylation conditions. Various in situ NMR methods such as 1D 1H and 31P, and 2D COSY, HMBC, and HMQC were employed and indicated the formation of the key catalyst, [rac-Rh2H2(μ-CO)2(CO)4(et,ph-P4)]2+, 4, and a number of other Rh-phosphine species on and off the catalytic cycle. …


Synthesis And Characterization Of Superparamagnetic Silica--Homopolypeptide Composite Particles, Sibel Turksen Jan 2004

Synthesis And Characterization Of Superparamagnetic Silica--Homopolypeptide Composite Particles, Sibel Turksen

LSU Doctoral Dissertations

Hierarchical construction and characterization of core-shell composite particles of interest are presented. The research described shows interest in new types of polymers that provide chirality and responsiveness which have been ignored for so long. The general synthetic design described in this document can be readily used as a model for other systems. Core-shell composite systems of interest consist of silica or silica-coated cobalt cores grafted with a homopolypeptide shell, mostly poly(epsilon-carbobenzyloxy-L-lysine) or poly(gamma-benzyl-L-glutamate). Core particles were decorated with amino groups through a silylation reaction. The amino groups initiated the polymerization (with attachment) of N-carboxyanhydride (NCA) monomers, resulting in a homopolypeptide …


Synthesis, Characterization And Study Of Novel Reagents For The Detection Of Saccharides And Amino Acids, Nadia Nadette St. Luce Jan 2004

Synthesis, Characterization And Study Of Novel Reagents For The Detection Of Saccharides And Amino Acids, Nadia Nadette St. Luce

LSU Doctoral Dissertations

The design of synthetic receptors for the recognition and sensing of saccharides and amino acids is currently a major challenge. This is due to inherent structural similarity and a lack of chromophoric or fluorophoric properties of these compounds. The synthesis and study of novel detection agents for bioactive molecules as well as mechanistic studies are presented herein. The elucidation of the mechanism by which tetraarylboronic acid resorcinarene interact with sugar molecules and promote a solution color change is explored. This vast collaborative study, reveals that DMSO solutions of boronic acid functionalized resorcinarene macrocycles afford visual color changes upon heating or …


Investigation Of Structure-Property Relationships Of Heavy-Fermion Materials, Robin Macaluso Jan 2004

Investigation Of Structure-Property Relationships Of Heavy-Fermion Materials, Robin Macaluso

LSU Doctoral Dissertations

This work focuses on how local structural features influence large effective masses, magnetism, and superconductivity that are yet to be understood in heavy-fermion materials. Three sets of structurally-related materials are discussed in light of dimensionality, layering effects, choice of transition metal, coordination, and structural distortions: LnnMIn3n+2 (Ln = La, Ce; n = 1, 2, ‡; M = Co, Rh, Ir), CePdGa6, and Ce2PdGa12, and CeNiSb3. The LnnMIn3n+2 (n = 1, 2, ‡; Ln = La, Ce; M = Rh, Ir) intergrowth homologous series presents a unique opportunity to study structure-property relationships. LnnMIn3n+2 (Ln = La, Ce; n = 1, 2; …


Evaluation Of A Deer-Activated Bio-Acoustic Frightening Device For Reducing Deer Damage In Cornfields, Jason M. Gilsdorf, Scott E. Hyngstrom, Kurt C. Vercauteren, Greg M. Clements, Erin E. Blankenship, Richard M. Engeman Jan 2004

Evaluation Of A Deer-Activated Bio-Acoustic Frightening Device For Reducing Deer Damage In Cornfields, Jason M. Gilsdorf, Scott E. Hyngstrom, Kurt C. Vercauteren, Greg M. Clements, Erin E. Blankenship, Richard M. Engeman

Other Publications in Wildlife Management

Deer (Odocoileus spp.) can cause substantial damage to agricultural crops, resulting in economic loses for producers. We developed a deer activated bio acoustic frightening device to reduce white-tailed deer (0. virginianus) damage in agricultural fields. The device consisted of an infrared detection system that activated an audio component which broadcast recorded distress and alarm calls of deer. We tested the device against unprotected controls in cornfields during the silking-tasseling stage of growth in July 2001. the device was not effective in reducing damage: track-count indices (F1,4=0.02, P=0.892), corn yield (F1,9=1.27, P=O.289), and estimated damage levels (F1,10=0.87, P=0.374) …


Which Mean Do You Mean?: An Exposition On Means, Mabrouck K. Faradj Jan 2004

Which Mean Do You Mean?: An Exposition On Means, Mabrouck K. Faradj

LSU Master's Theses

The objective of this thesis is to give a brief exposition on the theory of means. In Greek mathematics, means are intermediate values between two extremes, while in modern mathematics, a mean is a measure of the central tendency for a set of numbers. We begin by exploring the origin of the antique means and list the classical means. Next, we present an overview of the theories of binary means and n-ary means. We include a general discussion on axiomatic systems for means and present theorems on properties that characterize the most common types of means.


The Syntheses Of Novel Indicators And Materials For Chiral Separation, Rolanda Johnson Jan 2004

The Syntheses Of Novel Indicators And Materials For Chiral Separation, Rolanda Johnson

LSU Doctoral Dissertations

The colorimetric properties of resorcinarene solutions had not been fully investigated since von Baeyer's initial synthesis. We find that the solutions containing resorcinarene macrocycles develop color upon heating or standing. In the presence of saccharides, these solutions exhibit significant color changes which are readily observable by visual inspection. We determined that the solution color is due to macrocycle ring opening and oxidation. The optical responses to saccharides are due to complexation of the sugar with the acyclic chromophores. We have applied these mechanistic insights towards the challenging problems of the visual detection of saccharides and other important biologically analytes. In …


Influence Of The Marsh Edge On The Structure And Trophic Ecology Of The Fish And Macroinvertebrate Community In A Louisiana Estuarine Ecosystem, Guillermo Duque Jan 2004

Influence Of The Marsh Edge On The Structure And Trophic Ecology Of The Fish And Macroinvertebrate Community In A Louisiana Estuarine Ecosystem, Guillermo Duque

LSU Doctoral Dissertations

Habitat degradation of saltmarsh ecosystems reduces the suitability of the marsh as permanent environments for resident species and seasonal nursery grounds for transient fauna. This study was conducted in Terrebonne-Timbalier bays near Cocodrie, Louisiana. Fishes and macroinvertebrates were collected using a drop sampler in marsh-edge and open-water habitat types, in three locations (i.e., pond, channel, and bay), and four seasons (Fall of 2000, Winter of 2000-2001, and Spring and Summer of 2001). The specific objectives of this study were: (1) to determine the difference in composition and structure of fish and macroinvertebrate communities, (2) to establish the food habits of …


Giant Planar Hall Effect In Colossal Magnetoresistive La0.84sr0.16mno3 Thin Films, Y. Bason, L. Klein, J. -B. Yau, X. Hong, C. H. Ahn Jan 2004

Giant Planar Hall Effect In Colossal Magnetoresistive La0.84sr0.16mno3 Thin Films, Y. Bason, L. Klein, J. -B. Yau, X. Hong, C. H. Ahn

Xia Hong Publications

The transverse resistivity in thin films of La0.84Sr0.16MnO3 (LSMO) exhibits sharp field-symmetric jumps below TC . We show that a likely source of this behavior is the giant planar Hall effect combined with biaxial magnetic anisotropy. The effect is comparable in magnitude to that observed recently in the magnetic semiconductor Ga(Mn)As. It can be potentially used in applications such as magnetic sensors and nonvolatile memory devices.


Generalized Geologic Map For Land-Use Planning: Daviess County, Kentucky, E. Glynn Beck, David A. Williams, Daniel I. Carey Jan 2004

Generalized Geologic Map For Land-Use Planning: Daviess County, Kentucky, E. Glynn Beck, David A. Williams, Daniel I. Carey

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Geology And Structural Evolution Of The Tokat Massif (Eastern Pontides, Turkey), Ali̇ Yilmaz, Hüseyi̇n Yilmaz Jan 2004

Geology And Structural Evolution Of The Tokat Massif (Eastern Pontides, Turkey), Ali̇ Yilmaz, Hüseyi̇n Yilmaz

Turkish Journal of Earth Sciences

The Tokat Massif consists of a pre-Jurassic metamorphic complex that crops out widely between Amasya and Reşadiye in the western part of eastern Pontides, and which can be correlated with the Karakaya Complex of the western Pontides. This complex is named the Tokat Group, and is divided into two main units, namely, the Turhal Metamorphics and Devecidağ Mélange. The Turhal Metamorphics form a volcano-sedimentary sequence in the northern part of the Tokat Massif. The lower level of the formation is made up of gneiss, amphibolite and mica schists, whereas the upper part is represented by an alternation of mica schist, …


Radon Transforms And The Finite General Linear Groups, Michael E. Orrison Jan 2004

Radon Transforms And The Finite General Linear Groups, Michael E. Orrison

All HMC Faculty Publications and Research

Using a class sum and a collection of related Radon transforms, we present a proof G. James’s Kernel Intersection Theorem for the complex unipotent representations of the finite general linear groups. The approachis analogous to that used by F. Scarabotti for a proof of James’s Kernel Intersection Theorem for the symmetric group. In the process, we also show that a single class sum may be used to distinguish between distinct irreducible unipotent representations.


Random Walks With Badly Approximable Numbers, Doug Hensley, Francis Su Jan 2004

Random Walks With Badly Approximable Numbers, Doug Hensley, Francis Su

All HMC Faculty Publications and Research

Using the discrepancy metric, we analyze the rate of convergence of a random walk on the circle generated by d rotations, and establish sharp rates that show that badly approximable d-tuples in Rd give rise to walks with the fastest convergence.


Superionicity In Na3Po4: A Molecular Dynamics Simulation, Wei-Guo Yin, Jianjun Liu, Chun-Gang Duan, Wai-Ning Mei, R. W. Smith, John R. Hardy Jan 2004

Superionicity In Na3Po4: A Molecular Dynamics Simulation, Wei-Guo Yin, Jianjun Liu, Chun-Gang Duan, Wai-Ning Mei, R. W. Smith, John R. Hardy

John R. Hardy Papers

Fast ionic conduction in solid Na3PO4 is studied by use of molecular dynamics simulation based on the modified Lu-Hardy approach. We obtain reasonable agreement with experiment for the structural transition and diffusion of the sodium ions. All the sodium ions are found to contribute comparably to the high ionic conductivity. The results of the simulation are discussed in terms of the relative magnitude of the two proposed transport mechanisms: percolation and paddle-wheel. It appears to us that the percolation mechanism dominates the sodium diffusion.


Large Dielectric Constant And Maxwell-Wagner Relaxation In Bi2/3Cu3Ti4O12, Jianjun Liu, Chun-Gang Duan, Wei-Guo Yin, Wai-Ning Mei, R. W. Smith, John R. Hardy Jan 2004

Large Dielectric Constant And Maxwell-Wagner Relaxation In Bi2/3Cu3Ti4O12, Jianjun Liu, Chun-Gang Duan, Wei-Guo Yin, Wai-Ning Mei, R. W. Smith, John R. Hardy

John R. Hardy Papers

We studied frequency and temperature dependences of impedance, electric modulus, and dielectric permittivity of Bi2/3Cu3Ti4O12 in the ranges of 10−1–106 Hz and −150–200 °C, respectively. We first observed two electrical responses in the impedance and modulus formalisms. Then we detected a Debye-like relaxation in the permittivity formalism. Most interestingly, we found that the large dielectric constant of Bi2/3Cu3Ti4O12 is independent of the temperature and frequency below 150°C. The results are interpreted in terms of a two-layer model with conducting grains partitioned from each …


Cover - Table Of Contents Jan 2004

Cover - Table Of Contents

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Plant Parasitic Fungi Of Ten Tallgrass Prairies Of Iowa: Distribution And Prevalence, Lois H. Tiffany, George Knaphus Jan 2004

Plant Parasitic Fungi Of Ten Tallgrass Prairies Of Iowa: Distribution And Prevalence, Lois H. Tiffany, George Knaphus

Journal of the Iowa Academy of Science: JIAS

During the 1980s and 1990s, collections of fungal parasites on above ground parts of prairie plants in Iowa were made throughout the growing seasons. This report presents the fungi recorded from three groups of Iowa tallgrass prairies. The western group was composed of Dinesen, Steele and Stinson Prairie State Preserves, a Loess Hills group of collecting sites in Five Ridge and Runkel Prairie State Preserves and prairies at Waubonsie State Park. 180 species of fungi were collected on 116 hosts from these prairies. A central Iowa group of prairies associated with the Des Moines Lobe landform, Anderson, Doolittle, Kalsow and …


The Freshwater Mussels (Mollusca: Bivalvia: Unionidae) Of The Boone River, North Central Iowa, Ellet Hoke Jan 2004

The Freshwater Mussels (Mollusca: Bivalvia: Unionidae) Of The Boone River, North Central Iowa, Ellet Hoke

Journal of the Iowa Academy of Science: JIAS

A survey of the freshwater mussels of the Boone River conducted in September 1982 documented a fauna consisting of seventeen then extant or relict species. Analysis of museum records yielded one additional species unrecovered since 1937. Subsequent to the 1982 study, additional surveys were conducted in the region in 1984-1985 and 1998-1999 as a part of two statewide surveys. A comparison of the results of the three studies suggests a significant decline in the unionid fauna in the Boone River since 1982. While it is almost certain that a real decline in the fauna has occurred, the extent of this …


Editorial Board & Iowa Academy Of Science Officers And Directors Jan 2004

Editorial Board & Iowa Academy Of Science Officers And Directors

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Biomass Yield Stability In Alfalfa, Joseph G. Robins, Heathcliffe Riday, Sara J. Helland, E. Charles Brummer Jan 2004

Biomass Yield Stability In Alfalfa, Joseph G. Robins, Heathcliffe Riday, Sara J. Helland, E. Charles Brummer

Journal of the Iowa Academy of Science: JIAS

In addition to biomass production, alfalfa (Medicago sativa) cultivars also need to express yield stability across diverse environments. The objective of this experiment was to analyze the nature of biomass yield stability in ten commercial alfalfa cultivars by evaluating performance of individual genotypes. Biomass yield was measured in each of five environments across two years, and the yield stability computed for the overall cultivar mean performance and the mean performance of each of the genotypes comprising the cultivars using the genotype x environment variance statistic of Shukla and the superiority statistic of Lin and Binns'. The GxE variance of the …


Be Star Spectroscopy Using The Uca Fiber-Fed Spectrograph, Scott Austin Jan 2004

Be Star Spectroscopy Using The Uca Fiber-Fed Spectrograph, Scott Austin

Journal of the Arkansas Academy of Science

Beginning in June 2003, undergraduate students and the author have spectroscopically monitored bright Be stars using a custom built fiber-fed spectrograph attached to the UCA Observatory 11-inch Schmidt-Cassegrain telescope. We have obtained 0.8 Angstrom/pixel resolution spectra of the H-alpha line for over forty Be-Stars. Some have been observed on multiple dates in order to detect any temporal changes. Line profiles, velocities, and observed variations for some of these stars will be presented.


Quasi-Minimal Abelian Groups, Brendan Goldsmith, S. O. Hogain, S. Wallutis Jan 2004

Quasi-Minimal Abelian Groups, Brendan Goldsmith, S. O. Hogain, S. Wallutis

Articles

An abelian group $G$ is said to be quasi-minimal (purely quasi-minimal, directly quasi-minimal) if it is isomorphic to all its subgroups (pure subgroups, direct summands, respectively) of the same cardinality as $G$. Obviously quasi-minimality implies pure quasi-minimality which in turn implies direct quasi-minimality, but we show that neither converse implication holds. We obtain a complete characterisation of quasi-minimal groups. In the purely quasi-minimal case, assuming GCH, a complete characterisation is also established. An independence result is proved for directly quasi-minimal groups.


Studies In Cardiac Defribrillation, Eamonn Mckenna Jan 2004

Studies In Cardiac Defribrillation, Eamonn Mckenna

Masters

Cardiac disease resulting in cardiac arrest is one of the most common fatal diseases in the developed world. Defibrillation is the medical procedure used to correct the irregular cardiac rhythm (ventricular fibrillation (VF)) which is very often detected in patients suffering cardiac arrest. In the work reported in this thesis, two aspects of the defibrillation of patients in VF were examined. The first area of investigation concentrated on the use of multiple defibrillation electrodes to be used during closed chest (transthoracic) defibrillation. This study was carried out in a saline bath and centred on “focusing” electric fields from perimeter electrodes …


Staging Transformations For Multimodal Web Interaction Management, Michael Narayan, Christopher Williams, Saverio Perugini, Naren Ramakrishnan Jan 2004

Staging Transformations For Multimodal Web Interaction Management, Michael Narayan, Christopher Williams, Saverio Perugini, Naren Ramakrishnan

Computer Science Faculty Publications

Multimodal interfaces are becoming increasingly ubiquitous with the advent of mobile devices, accessibility considerations, and novel software technologies that combine diverse interaction media. In addition to improving access and delivery capabilities, such interfaces enable flexible and personalized dialogs with websites, much like a conversation between humans. In this paper, we present a software framework for multimodal web interaction management that supports mixed-initiative dialogs between users and websites. A mixed-initiative dialog is one where the user and the website take turns changing the flow of interaction. The framework supports the functional specification and realization of such dialogs using staging transformations – …


Automatically Generating Interfaces For Personalized Interaction With Digital Libraries, Saverio Perugini, Naren Ramakrishnan, Edward A. Fox Jan 2004

Automatically Generating Interfaces For Personalized Interaction With Digital Libraries, Saverio Perugini, Naren Ramakrishnan, Edward A. Fox

Computer Science Faculty Publications

We present an approach to automatically generate interfaces supporting personalized interaction with digital libraries; these interfaces augment the user-DL dialog by empowering the user to (optionally) supply out-of-turn information during an interaction, flatten or restructure the dialog, and inquire about dialog options. Interfaces generated using this approach for CITIDEL are described.


Program Transformations For Information Personalization, Saverio Perugini Jan 2004

Program Transformations For Information Personalization, Saverio Perugini

Computer Science Faculty Publications

Personalization constitutes the mechanisms and technologies necessary to customize information access to the end-user. It can be defined as the automatic adjustment of information content, structure, and presentation. The central thesis of this dissertation is that modeling interaction explicitly in a representation, and studying how partial information can be harnessed in it by program transformations to direct the flow of the interaction, can provide insight into, reveal opportunities for, and define a model for personalized interaction. To evaluate this thesis, a formal modeling methodology is developed for personalizing interactions with information systems, especially hierarchical hypermedia, based on program transformations. The …


Diel Activity Patterns, Space Utilization, Seasonal Distribution And Population Structure Of The Yellow Stingray, Urobatis Jamaicensis (Cuvier, 1817) In South Florida With Comments On Reproduction., Daniel P. Fahy Jan 2004

Diel Activity Patterns, Space Utilization, Seasonal Distribution And Population Structure Of The Yellow Stingray, Urobatis Jamaicensis (Cuvier, 1817) In South Florida With Comments On Reproduction., Daniel P. Fahy

HCNSO Student Theses and Dissertations

The yellow stingray, Urobatis jamaicensis is the most common elasmobranch in the coastal waters of Southeast Florida. Despite their common occurrence the ecology of yellow stingrays remains poorly understood. In particular, yellow stingray daily movements, space utilization, seasonal distribution and population structure have not been described. This study was conducted to address the lack of knowledge of these fundamental life history parameters and to provide further information on the ecology of U. jamaicensis in coastal waters of Broward County, Florida.

The activity patterns and space utilization of U. jamaicensis were assessed by manual tracking with ultrasonic telemetry. Telemetry tracking of …


Stable Hydrogen Isotope Analysis Of Bat Hair As Evidence For Seasonal Molt And Long-Distance Migration, Paul M. Cryan, Michael A. Bogan, Robert O. Rye, Gary P. Landis, Cynthia L. Kester Jan 2004

Stable Hydrogen Isotope Analysis Of Bat Hair As Evidence For Seasonal Molt And Long-Distance Migration, Paul M. Cryan, Michael A. Bogan, Robert O. Rye, Gary P. Landis, Cynthia L. Kester

United States Geological Survey: Staff Publications

Although hoary bats (Lasiurus cinereus) are presumed to be migratory and capable of long-distance dispersal, traditional marking techniques have failed to provide direct evidence of migratory movements by individuals. We measured the stable hydrogen isotope ratios of bat hair (∂Dh) and determined how these values relate to stable hydrogen isotope ratios of precipitation (∂Dp). Our results indicate that the major assumptions of stable isotope migration studies hold true for hoary bats and that the methodology provides a viable means of determining their migratory movements. We present evidence that a single annual molt occurs in L. cinereus …