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

Digital Commons Network™

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

2003

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 8041 - 8070 of 8169

Full-Text Articles in Entire DC Network

A Stellar Parameter Calibration Of Iue Data For The Determination Of The Present Day Mass Function Of High Mass Stars, Kenneth Thomas Taylor Jan 2003

A Stellar Parameter Calibration Of Iue Data For The Determination Of The Present Day Mass Function Of High Mass Stars, Kenneth Thomas Taylor

LSU Master's Theses

A study of stellar atmosphere models and the photometric quantity R is presented here, with R being the ratio of the integrated de-reddened fluxes from the two wavelength regions of the International Ultraviolet Explorer (IUE) satellite cameras. The effective temperatures and surface gravities of the stellar atmospheres were calibrated against R and absolute magnitude, using stellar evolution tracks from the literature, and applied to over 156 LMC stars whose masses and mass function are then derived from the results. The results show that the effective temperatures and surface gravities of stars derived from R and absolute magnitude correlate well with …

Go to article

Pcr Inhibition And Toxic Effects By Sediment Samples Exposed To Drilling Muds, Neal Gilpin Satterly Jan 2003

Pcr Inhibition And Toxic Effects By Sediment Samples Exposed To Drilling Muds, Neal Gilpin Satterly

LSU Master's Theses

This study evaluated the PCR inhibition and toxic effects by sediment samples exposed to drilling muds. This information was gathered in an attempt to identify what effect, if any, drilling muds had on the microbial community structure in sediments around four specific oil-drilling platforms in the Gulf of Mexico. Sediment samples were taken before and after drilling had taken place around two platforms (GB516 and VK916), and sediment samples were taken after drilling had taken place around two other platforms (MC292 and GB602). After using traditional, non-selective DNA extraction methods, successful amplification took place via PCR with all pre-drilling samples …

Go to article

A Methodology For Deriving Performance Measures From Spatio-Temporal Traffic Contour Maps Using Digital Image Analysis Procedures, Prashanth Kotha Jan 2003

A Methodology For Deriving Performance Measures From Spatio-Temporal Traffic Contour Maps Using Digital Image Analysis Procedures, Prashanth Kotha

LSU Master's Theses

The main focus of this study is to improve the data analysis tools used in performance monitoring and level of service assessment of freeway systems. The proposed study presents a methodology to develop new second-order statistical measures that are derived from texture characterization techniques in the field of digital image analysis. The new measures are capable of extracting properties such as smoothness, homogeneity, regularity, and randomness in traffic behavior from the spatio-temporal traffic contour maps. To study the new performance measures a total of 14270, 15-min traffic contour maps were generated for a section of 3.4 miles of I-4 in …

Go to article

Tracking Down The Marrons: Archaeo-Geography Of Marronage In The Caribbean, E. Kofi Agorsah Jan 2003

Tracking Down The Marrons: Archaeo-Geography Of Marronage In The Caribbean, E. Kofi Agorsah

Black Studies Faculty Publications and Presentations

As the Maroons escaped from enslavement into unknown and inaccessible environments, they relied on their mental maps developed through sequential exploration of those environments to establish and defend their settlements. Initially they would take advantage of the knowledge of the areas surrounding the plantations from which they escaped, explore them thoroughly and then, at the appropriate time, link their escape routes and locations to those mental maps that they had acquired. That knowledge would have helped them to develop networks of familiar pathways and landmarks along, and around which, they arranged their settlements. This paper suggests that knowledge of such …

Go to article

Development And Implementation Of Fine Structure Aerosol Spectrum Coagulation Kernels And Deposition Mechanisms Using Advanced Nodal Method In The Caerot Code, Hyeongkae Park Jan 2003

Development And Implementation Of Fine Structure Aerosol Spectrum Coagulation Kernels And Deposition Mechanisms Using Advanced Nodal Method In The Caerot Code, Hyeongkae Park

LSU Master's Theses

Aerosol transport in confined spaces was studied via numerical simulation using the dynamic aerosol equation, which is Boltzmann?s transport equation at the hydrodynamic limit. Until recent years, there existed no comprehensive computational tool to predict the spatial distribution and time evolution of aerosol size spectrum. A previously developed code, INDASOL3D, solves the dynamic aerosol equation by using a homogenized control-volume based finite difference method applying the group sectional method on the coagulation dynamics. However, quantitative correctness has not been satisfactory. In this thesis, two new codes (SAEROSA, and CAEROT) were developed. SAEROSA computes the time evolution of the size spectrum …

Go to article

A Comparative Study Of Two Treatment Approaches For Improving Middle School Students' Reading Comprehension, Vessa Annette Cartmill Jan 2003

A Comparative Study Of Two Treatment Approaches For Improving Middle School Students' Reading Comprehension, Vessa Annette Cartmill

LSU Master's Theses

The purpose of this study was to examine the efficacy of having material read to and discussed with learning disabled students (i.e., a compensatory approach termed Accommodated Reading in this study) compared to teaching the literate language of text structures to students (i.e., a language intervention approach termed Communicative Reading Strategies). Participants were two 5th grade students and three 6th grade students, classified as learning disabled according to criteria of the State of Louisiana. Students took part in the study 3 times per week, 40 minutes per day for 5 ½ weeks during their regular speech-language therapy time. After each …

Go to article

The Roles Of Silanes As Coupling Reagents And In Deoxygenative Alkylations, Andrea S. Dupre Jan 2003

The Roles Of Silanes As Coupling Reagents And In Deoxygenative Alkylations, Andrea S. Dupre

LSU Master's Theses

Silane reagents play important roles in many areas of organic synthesis. This is primarily due to the ability of silanes to bond to more ligands than the traditional four to become hypervalent (i.e. penta- or hexavalent). This hypervalency causes the silicon center to become more Lewis Acidic and causes the formation of carbon nucleophiles from organosilane ligands. These nucleophiles have been used to perform many cross-coupling reactions with organohalide reagents. The research presented in this thesis reports the utility of silane reagents in cross-coupling reactions of Grignard reagents with alkyl halides. This cross coupling was desirable because the silane should …

Go to article

Thermohydrodynamic Analysis Of Compressible Gas Flow In Compliant Foil Bearings, Zhengchun Peng Jan 2003

Thermohydrodynamic Analysis Of Compressible Gas Flow In Compliant Foil Bearings, Zhengchun Peng

LSU Master's Theses

This thesis deals with the development of mathematical models and numerical schemes for simulating the hydrodynamic pressure and temperature rise of compliant foil bearings lubricated by a thin gas film in between its compliant bearing surface and the rotating shaft. The model accounts for the compressibility of gas, the compliance of the bearing surface, and the interaction between the pressure field and temperature field of the gas film in the bearing system. Numerical solutions obtained over a fairly large range of operating speeds show excellent agreement with existing experimental data from both load performance test and bearing temperature measurement. A …

Go to article

Uncovering Strata: An Investigation Into The Graphic Innovations Of Geologist Henry T. De La Beche, Renee M. Clary Jan 2003

Uncovering Strata: An Investigation Into The Graphic Innovations Of Geologist Henry T. De La Beche, Renee M. Clary

LSU Doctoral Dissertations

An historical investigation into the types of illustrations in the Golden Age of Geology (1788-1840) revealed the nature and progression of graphic representation at the dawning of geology as a science. Exhaustive sampling of geology texts published in the period of focus proceeded until saturation was achieved. Qualitative analysis and evaluation of early illustrations were accomplished with Edward R. Tufte's theory of graphic design. Hypothesis testing around a correlation coefficient revealed significance at the 99% confidence level for relationships between publication year and number of included graphics, and publication year and the graphic density of texts. Henry T. De la …

Go to article

Synchrotron Radiation As A Probe Of Chemical Information Using Novel Experimental Configurations, George Farquar Jan 2003

Synchrotron Radiation As A Probe Of Chemical Information Using Novel Experimental Configurations, George Farquar

LSU Doctoral Dissertations

Determination of chemical information with synchrotron radiation is an area of great scientific interest, and expanding the range of available techniques is the topic of this dissertation. The experimental methods described herein allows for a significant advancement of the availability of subtle chemical information. This dissertation uses ionizing radiation to study three chemical systems. First, the l=3 shape resonance in CO is investigated using a cryogenically cooled gas jet. Shape resonant effects have been studied for many years. Previously, this was accomplished on the vibrational structure of molecules with a limited ability to determine the rotational substructure effects. A dramatic …

Go to article

Comparative Studies Of Evolutionary Responses To Light Environments In Arabidopsis, Massimo Pigliucci, Heidi Pollard, Mitchell B. Cruzan Jan 2003

Comparative Studies Of Evolutionary Responses To Light Environments In Arabidopsis, Massimo Pigliucci, Heidi Pollard, Mitchell B. Cruzan

Biology Faculty Publications and Presentations

In this article, we compare the reaction norms to foliage shade (changes in light quality, spatially fine-grained environmental variation) and photoperiod (day length, spatially coarse-grained environmental variation) in several haplotypes of Arabidopsis thaliana from Scandinavia. We found that both across-environment means and phenotypic plasticities evolved continuously and very rapidly within this group. Both character means and trait plasticities were highly integrated, in part as predicted by the adaptive plasticity hypothesis for response to foliage shade (the so-called shade-avoidance syndrome). We found that a significant but small fraction of the variance in across-treatment trait means and plasticities in response to one …

Go to article

A Biooptical Model Of Irradiance Distribution And Photosynthesis In Seagrass Canopies, Richard C. Zimmerman Jan 2003

A Biooptical Model Of Irradiance Distribution And Photosynthesis In Seagrass Canopies, Richard C. Zimmerman

OES Faculty Publications

Although extremely vulnerable to coastal eutrophication, seagrasses represent important structuring elements and sources of primary production in shallow waters. They also generate an optical signature that can be tracked remotely. Accurate knowledge of light absorption and scattering by submerged plant canopies permits the calculation of important plant- and ecosystem-level properties, including rates of photosynthesis, vegetation abundance, and distribution. The objectives of this study were to develop a realistic, yet simply parameterized two-flow model of plane irradiance distribution through a seagrass canopy submerged in an optically active water column, to evaluate its performance against in situ measurements, and to explore the …

Go to article

A Multilevel Discontinuous Galerkin Method, Jay Gopalakrishnan, Guido Kanschat Jan 2003

A Multilevel Discontinuous Galerkin Method, Jay Gopalakrishnan, Guido Kanschat

Mathematics and Statistics Faculty Publications and Presentations

A variable V-cycle preconditioner for an interior penalty finite element discretization for elliptic problems is presented. An analysis under a mild regularity assumption shows that the preconditioner is uniform. The interior penalty method is then combined with a discontinuous Galerkin scheme to arrive at a discretization scheme for an advection-diffusion problem, for which an error estimate is proved. A multigrid algorithm for this method is presented, and numerical experiments indicating its robustness with respect to diffusion coefficient are reported.

Go to article

A Schwarz Preconditioner For A Hybridized Mixed Method, Jay Gopalakrishnan Jan 2003

A Schwarz Preconditioner For A Hybridized Mixed Method, Jay Gopalakrishnan

Mathematics and Statistics Faculty Publications and Presentations

In this paper, we provide a Schwarz preconditioner for the hybridized versions of the Raviart-Thomas and Brezzi-Douglas-Marini mixed methods. The preconditioner is for the linear equation for Lagrange multipliers arrived at by eliminating the ux as well as the primal variable. We also prove a condition number estimate for this equation when no preconditioner is used. Although preconditioners for the lowest order case of the Raviart-Thomas method have been constructed previously by exploiting its connection with a nonconforming method, our approach is different, in that we use a new variational characterization of the Lagrange multiplier equation. This allows us to …

Go to article

Congressional Power To Regulate Sex Discrimination: The Effect Of The Supreme Court's "New Federalism", Calvin R. Massey Jan 2003

Congressional Power To Regulate Sex Discrimination: The Effect Of The Supreme Court's "New Federalism", Calvin R. Massey

Faculty Scholarship

No abstract provided.

Go to article

Quantifying Habitat Quality Of Larval Bay Anchovy (Anchoa Mitchilli) In Chesapeake Bay By Linking An Individual-Based Model With Spatially-Detailed Field Data, Aaron Thomas Adamack Jan 2003

Quantifying Habitat Quality Of Larval Bay Anchovy (Anchoa Mitchilli) In Chesapeake Bay By Linking An Individual-Based Model With Spatially-Detailed Field Data, Aaron Thomas Adamack

LSU Master's Theses

Larval bay anchovy (Anchoa mitchilli) habitat quality in Chesapeake Bay was predicted using an individual-based model applied to spatially-detailed field data from Rilling and Houde (1999). Habitat quality was predicted using the ratio of instantaneous mortality rate to instantaneous growth rate. Model predictions of habitat quality were compared to field estimates of habitat quality derived from the spatially-detailed field data. Three sets of one-day simulations were performed to estimate larval growth and mortality rates throughout Chesapeake Bay during June and during July 1993. Field-based simulations used field data to estimate the model inputs of water temperature, zooplankton densities, and the …

Go to article

Denoising Techniques - A Comparison, Sarita Veera Dangeti Jan 2003

Denoising Techniques - A Comparison, Sarita Veera Dangeti

LSU Master's Theses

Visual information transmitted in the form of digital images is becoming a major method of communication in the modern age, but the image obtained after transmission is often corrupted with noise. The received image needs processing before it can be used in applications. Image denoising involves the manipulation of the image data to produce a visually high quality image. This thesis reviews the existing denoising algorithms, such as filtering approach, wavelet based approach, and multifractal approach, and performs their comparative study. Different noise models including additive and multiplicative types are used. They include Gaussian noise, salt and pepper noise, speckle …

Go to article

Supply Chain Models For An Assembly System With Preprocessing Of Raw Materials, Mohammad Anwar Ashek Rahman Jan 2003

Supply Chain Models For An Assembly System With Preprocessing Of Raw Materials, Mohammad Anwar Ashek Rahman

LSU Master's Theses

An assembly line that procures raw materials from outside suppliers and processes the materials into finished products is considered in this research. An ordering policy is proposed for raw materials to meet the requirement of a production facility, which, in turn, must deliver finish products in a fixed quantity at a fixed time interval to the outside buyers. Two different types of raw materials, ‘unfinished’ and ‘ready-to-use’, are procured for the manufacturing system. The ‘unfinished raw materials’ are turned into ‘processed raw materials’ after preprocessing. In the assembly line, the ‘processed raw materials’ and the ‘ready raw materials’ are assembled …

Go to article

The Phylogenetic Underpinnings For Spatial Patterns Of Morphological Disparity: Analyses Using Strombid Gastropods, Jared M. Latiolais Jan 2003

The Phylogenetic Underpinnings For Spatial Patterns Of Morphological Disparity: Analyses Using Strombid Gastropods, Jared M. Latiolais

LSU Master's Theses

Attempting to understand the relationship between morphological and taxonomic diversification has become a central concern of both paleobiology and ecology. Ordinating species in morphospace provides a visual representation of trends in form. In morphospace analysis, each axis of a graph represents a quantitative measure of a morphological trait or combination of traits found in a group of closely related organisms. How species fill open morphospace provide some insight into the history of adaptive radiations. Furthermore, if we map species' positions in morphospace onto an independently derived phylogenetic hypothesis, we should be able to detect trends in morphological divergence along different …

Go to article

Establishment Of A Callus Culture And Measurement Of Seasonal Changes In Secondary Compound Production In Eucommia Ulmoides Oliver, Erica Deshay Gray Jan 2003

Establishment Of A Callus Culture And Measurement Of Seasonal Changes In Secondary Compound Production In Eucommia Ulmoides Oliver, Erica Deshay Gray

LSU Master's Theses

Eucommia ulmoides Oliver (Eucommiaceae) contains many secondary metabolites, including the lignan pinoresinol di-O-β] glucoside (PG) and the iridoid glycoside aucubin (AU), which have been shown to have anti-hypertensive, antioxidant, and hepatoprotective biological properties. The main objective of this research was to create a new agricultural crop in Louisiana for maintaining healthy blood pressure levels. This was done by: 1) determining the seasonal changes in the concentrations of PG and AU in four-year-old E. ulmoides trees in cultivation in Baton Rouge, Louisiana using Thin Layer Chromatography and High Pressure Liquid Chromatography (HPLC) and 2) determining production of secondary metabolites of E. …

Go to article

Influences On State-Level Policies For Wildfire Risk Reduction, Marios Anastasis Valiantis Jan 2003

Influences On State-Level Policies For Wildfire Risk Reduction, Marios Anastasis Valiantis

LSU Master's Theses

Wildland fires are part of the United State’s history and culture. The human dimension of State wildland fire management, - the relationship of people and wildland fire in America- is an important and driving force in how federal and state agencies respond to wildland fire, now and in the future. In many ways, the critical element for the management of wildland fire is the management of people, communities, and organizations. Explosive growth in the wildland-urban interface puts entire communities, their associated infrastructure and the socioeconomic fabric that holds communities together at a high risk from wildland fire. Year after year …

Go to article

Use Of Dea To Evaluate Non-Linear And Imprecise Information In Construction Contractor Performance, Gerald H. Williams, Timothy R. Anderson Jan 2003

Use Of Dea To Evaluate Non-Linear And Imprecise Information In Construction Contractor Performance, Gerald H. Williams, Timothy R. Anderson

Engineering and Technology Management Faculty Publications and Presentations

This paper explores the use of Data Envelopment Analysis as a tool to evaluate the efficiency of building construction projects in Oregon where the inputs, including, "reported information" available prior to pricing and contractor selection is imprecise or at least, cannot be entirely or accurately captured by exogenous measures. This work builds on prior work in the field that evaluated missing, imprecise or non-existent information in DEA models and has broad application to the service sector of the economy where information is the prime input in the system.

Go to article

Snow-Patch Influence On Soil Biogeochemical Processes And Invertebrate Distribution In The Mcmurdo Dry Valleys, Antarctica, Michael N. Gooseff, John E. Barrett, Peter T. Doran, Andrew G. Fountain, W. Berry Lyons, Andrew N. Parsons, Dorota L. Porazinska, Ross A. Virginia, Diana H. Wall Jan 2003

Snow-Patch Influence On Soil Biogeochemical Processes And Invertebrate Distribution In The Mcmurdo Dry Valleys, Antarctica, Michael N. Gooseff, John E. Barrett, Peter T. Doran, Andrew G. Fountain, W. Berry Lyons, Andrew N. Parsons, Dorota L. Porazinska, Ross A. Virginia, Diana H. Wall

Geography Faculty Publications and Presentations

The McMurdo Dry Valleys is the largest of the ice-free areas in Antarctica. Precipitation events in excess of 1 cm of snow accumulation are rare. During the winter, snow is transported by strong katabatic winds blowing from the polar plateau, and deposited into the lee of topographic features (e.g., stream channels and other topographic depressions). At the start of the austral summer (early October), as much as 10% of the valley soils may be covered by distributed snow patches. Because liquid water is the primary driver of biological, physical, and chemical processes in this polar desert, quantifying fluxes of water …

Go to article

Subglacial Thermal Balance Permits Ongoing Grounding Line Retreat Along The Siple Coast Of West Antarctica, Byron R. Parizek, Richard B. Alley, Christina L. Hulbe Jan 2003

Subglacial Thermal Balance Permits Ongoing Grounding Line Retreat Along The Siple Coast Of West Antarctica, Byron R. Parizek, Richard B. Alley, Christina L. Hulbe

Geology Faculty Publications and Presentations

Changes in the discharge of West Antarctic ice streams are of potential concern with respect to global sea level. The six relatively thin, fast-flowing Ross ice streams are of interest as low-slope end-members among Antarctic ice streams. Extensive research has demonstrated that these "rivers of ice" have a history of relatively high-frequency (óO(100) years), asynchronous discharge variations with evolving lateral boundaries. Amidst this variability, a ~1300 km grounding-line retreat has occurred since the Last GlacialMaximum. Numerical studies of Ice Stream D (Parizek and others, 2002) indicate that a proposed thermal-regulation mechanism(Clarke and Marshall, 1998; Hulbe and MacAyeal,1999; Tulaczyk and others, …

Go to article

Notices Jan 2003

Notices

Contemporary Aesthetics (Journal Archive)

No abstract provided.

Go to article

Simplicity Of Ultragraph Algebras, Mark Tomforde Jan 2003

Simplicity Of Ultragraph Algebras, Mark Tomforde

Dartmouth Scholarship

In this paper we analyze the structure of C*-algebras associated to ultragraphs, which are generalizations of directed graphs. We characterize the simple ultragraph algebras as well as deduce necessary and sufficient conditions for an ultragraph algebra to be purely infinite and to be AF. Using these techniques we also produce an example of an ultragraph algebra which is neither a graph algebra nor an Exel-Laca algebra. We conclude by proving that the C*-algebras of ultragraphs with no sinks are Cuntz-Pimsner algebras.

Go to article

Tracers Of Wood Smoke, M. A. K. Khalil, R. A. Rasmussen Jan 2003

Tracers Of Wood Smoke, M. A. K. Khalil, R. A. Rasmussen

Physics Faculty Publications and Presentations

Smoke from wood burning is a significant source of air pollution in many parts of the world. When several sources simultaneously cause air pollution, it is often difficult to determine how much comes from wood burning. Woodsmoke has unique chemical characteristics that can be used as indicators, including elemental composition, particularly potassium and chlorine, the ratios of organic and elemental carbon, and gases such as methyl chloride. This paper deals with formulating and applying the chemical mass balance approach incorporating both gas- and aerosol-phase tracers to a study carried out at Olympia-Lacey in Washington. In this study, three types of …

Go to article

The Impact Of Pollution On Stellar Evolution Models, Aaron Dotter, Brian Chaboyer Jan 2003

The Impact Of Pollution On Stellar Evolution Models, Aaron Dotter, Brian Chaboyer

Dartmouth Scholarship

An approach is introduced for incorporating the concept of stellar pollution into stellar evolution models. The approach involves enhancing the metal content of the surface layers of stellar models. In addition, the surface layers of stars in the mass range of 0.5-2.0 M☉ are mixed to an artificial depth motivated by observations of lithium abundance. The behavior of polluted stellar evolution models is explored assuming the pollution occurs after the star has left the fully convective pre-main-sequence phase. Stellar models polluted with a few Earth masses (M⊕) of iron are significantly hotter than stars of the …

Go to article

Estimating Watershed Biodiversity: An Empirical Study Of The Chesapeake Bay In Maryland, Usa, Junko Morimoto, Helena Voinov, Matthew A. Wilson, Robert Costanza Jan 2003

Estimating Watershed Biodiversity: An Empirical Study Of The Chesapeake Bay In Maryland, Usa, Junko Morimoto, Helena Voinov, Matthew A. Wilson, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

There has been increasing demand for rigorous methods for evaluating biodiversity, one of the ecosystem services that sustains and fulfills human life. After carefully examining the literature, we found three key points that should be taken into account when we evaluate biodiversity. The first point is that any "indicator species" tends to be a leaky target of biodiversity. The second point is that "buffering" that is useful for representing the ecological concept of boundaries should have scientific meanings. The third point is that a "watershed" that integrates most natural processes is advantageous as the spatial range for evaluation. Based on …

Go to article

Ordering Genetic Algorithm Genomes With Reconstructability Analysis, Stephen Shervais, Martin Zwick Jan 2003

Ordering Genetic Algorithm Genomes With Reconstructability Analysis, Stephen Shervais, Martin Zwick

Complex Systems Faculty Publications and Presentations

The building block hypothesis implies that genetic algorithm effectiveness is influenced by the relative location of epistatic genes on the chromosome. We find that this influence exists, but depends on the generation in which it is measured. Early in the search process it may be more effective to have epistatic genes widely separated. Late in the search process, effectiveness is improved when they are close together. The early search effect is weak but still statistically significant; the late search effect is much stronger and plainly visible. We demonstrate both effects with a set of simple problems, and show that infonnation-theoretic …

Go to article

First Prev Next Last