Physical Sciences and Mathematics Commons^™

Combined Kerr Microscope And Magnetic Force Microscope For Variable Temperature Ultrahigh Vacuum Investigations, D. Peterka, Axel Enders, G. Haas, Klaus Kern

Axel Enders Publications

A new system combining a Kerr microscope and a magnetic force microscope for the study of magnetic domains in ultrathin films under ultrahigh vacuum conditions is presented. Due to the overlapping imaging range of both techniques magnetic domains can be investigated over a lateral range from millimeter down to fractions of a micrometer. Experiments can be done at variable temperatures, from 80 K to 600 K. First results are presented showing the same magnetic domain in a three monolayer Fe film on Cu (100) imaged with both techniques.

Nebraska Birds In Recorded History, Fritz L. Knopf

United States Geological Survey: Staff Publications

The critical image of historical perspective is lacking in much of conservation biology's dialogue on protecting biotic diversity. Some biologists offer that the vision for bird conservation on the Central Grasslands of North America is to secure at least fragments of the avian assemblage that coexisted with Native Americans when Europeans first arrived. Nowhere, however, has anyone really tried to re-create such a historical image in any biological arena, until now.

Eolian Sand Transport Pathways In The Southwestern United States: Importance Of The Colorado River And Local Sources, Daniel R. Muhs, Richard L. Reynolds, Josh Been, Gary Skipp

United States Geological Survey: Staff Publications

Geomorphologists have long recognized that eolian sand transport pathways extend over long distances in desert regions. Along such pathways, sediment transport by wind can surmount topographic obstacles and cross major drainages. Recent studies have suggested that three distinct eolian sand transport pathways exist (or once existed) in the Mojave and Sonoran Desert regions of the southwestern United States. One hypothesized pathway is eolian sand transport from the eastern Mojave Desert of California into western Arizona, near Parker, and would require sand movement across what must have been at least a seasonally dry Colorado River valley. We tested this hypothesis by …

Quaternary Sedimentation And Subsidence History Of Lake Baikal, Siberia, Based On Seismic Stratigraphy And Coring, S. M. Colman, E. B. Karabanov, C. H. Nelson Iii

United States Geological Survey: Staff Publications

The long, continuous, high-latitude, stratigraphic record of Lake Baikal was deposited in three broad sedimentary environments, defined by high-resolution seismic-reflection and coring methods: (1) turbidite depositional systems, by far the most widespread, characterizing most of the margins and floors of the main basins of the lake, (2) large deltas of major drainages, and (3) tectonically or topographically isolated ridges and banks. Holocene sedimentation rates based on radiocarbon ages vary by more than an order of magnitude among these environments, from less than about 0.03 mm/yr on ridges and banks to more than about 0.3 mm/yr on basin floors. Extrapolating these …

Birth Of The Modern Chesapeake Bay Estuary Between 7.4 And 8.2 Ka And Implications For Global Sea-Level Rise, John F. Bratton, Steven M. Colman, E. Robert Thieler, Robert R. Seal Ii

United States Geological Survey: Staff Publications

Two major pulses of sea-level rise are thought to have taken place since the last glacial maximum – meltwater pulses (mwp) 1A (12 cal ka) and 1B (9.5 cal ka). Between mwp 1B and about 6 cal ka, many of the complex coastal ecosystems which ring the world’s oceans began to form. Here we report data for rhenium, carbon isotopes, total organic carbon, and fossil oysters from Chesapeake Bay which span the transition from fresh to brackish water conditions in the bay in the mid- Holocene. These data constrain sea-level change and resulting environmental change in the bay. They indicate …

Acquisition And Evaluation Of Thermodynamic Data For Morenosite-Retgersite Equilibria At 0.1 Mpa, I-Ming Chou, Robert R. Seal Ii

United States Geological Survey: Staff Publications

Metal-sulfate salts in mine drainage environments commonly occur as solid solutions containing Fe, Cu, Mg, Zn, Al, Mn, Ni, Co, Cd, and other elements. Thermodynamic data for some of the endmember salts containing Fe, Cu, Zn, and Mg have been collected and evaluated previously, and the present study extends to the system containing Ni. Morenosite (NiSO₄•7H₂O)-retgersite (NiSO₄•6H₂O) equilibria were determined along five humidity buffer curves at 0.1 MPa and between 5 and 22 °C. Reversals along these humidity-buffer curves yield ln K = 17.58–6303.35/T, where K is the equilibrium constant, …

Effects Of Crustal Stresses On Fluid Transport In Fractured Rock: Case Studies From Northeastern And Southwestern Usa, Roger H. Morin, William Z. Savage

United States Geological Survey: Staff Publications

The link between stress and hydrologic properties was examined at two sites that are distinguished by different rock types and different stress states. This investigation is based upon the analysis and interpretation of geophysical logs obtained in water wells at the two locations. At the northeast site (Newark Basin), the hydrologic characteristics of sedimentary rocks are dependent upon the relationship to the current regional stress field of two primary types of orthogonal features that serve as preferential pathways for fluid flow. Subhorizontal bedding-plane partings are highly transmissive near the surface and delineate transversely isotropic fluid flow at shallow depths. With …

Influence Of The Pacific Decadal Oscillation On The Climate Of The Sierra Nevada, California And Nevada, Larry Benson, Braddock Linsley, Joe Smoot, Scott Mensing, Steve Lund, Scott Stine, Andre Sarna-Wojcicki

United States Geological Survey: Staff Publications

Mono Lake sediments have recorded five major oscillations in the hydrologic balance between A.D. 1700 and 1941. These oscillations can be correlated with tree-ring-based oscillations in Sierra Nevada snowpack. Comparison of a tree-ring-based reconstruction of the Pacific Decadal Oscillation (PDO) index (D’Arrigo et al., 2001) with a coral-based reconstruction of Subtropical South Pacific sea-surface temperature (Linsley et al., 2000) indicates a high degree of correlation between the two records during the past 300 yr. This suggests that the PDO has been a pan-Pacific phenomena for at least the past few hundred years. Major oscillations in the hydrologic balance of the …

Age Of The Mono Lake Excursion And Associated Tephra, Larry Benson, Joseph Liddicoat, Joseph Smoot, Andrei Sarna-Wojcicki, Robert M. Negrini, Steve Lund

United States Geological Survey: Staff Publications

The Mono Lake excursion (MLE) is an important time marker that has been found in lake and marine sediments across much of the Northern Hemisphere. Dating of this event at its type locality, the Mono Basin of California, has yielded controversial results with the most recent effort concluding that the MLE may actually be the Laschamp excursion (Earth Planet. Sci. Lett. 197 (2002) 151). We show that a volcanic tephra (Ash #15) that occurs near the midpoint of the MLE has a date (not corrected for reservoir effect) of 28,620 ± 300 ¹⁴C yr BP (~32,400 GISP2 yr BP) …

Aeolian Cliff-Top Deposits And Buried Soils In The White River Badlands, South Dakota, Usa, J. Elmo Rawling Iii, Glen G. Fredlund, Shannon Mahan

United States Geological Survey: Staff Publications

Aeolian deposits in the North American Great Plains are important sources of Holocene palaeoenvironmental records. Although there are extensive studies on loess and dune records in the region, little is known about records in aeolian cliff-top deposits. These are common on table (mesa) edges in the White River Badlands. These sediments typically have loam and sandy-loam textures with dominantly very fine sand, 0.5–1% organic carbon and 0.5–5% CaCO₃. Some of these aeolian deposits are atypically coarse and contain granules and fine pebbles. Buried soils within these deposits are weakly developed with A-C and A-AC-C profiles. Beneath these are …

Quaternary Loess-Paleosol Sequences As Examples Of Climate-Driven Sedimentary Extremes, Daniel R. Muhs, E. Arthur Bettis Iii

United States Geological Survey: Staff Publications

Loess is a widespread, wind-transported, silt-dominated deposit that contains geologic archives of atmospheric circulation and paleoclimate on continents. Loess may cover as much as 10% of the Earth’s land surface. It is composed mainly of quartz, feldspars, and clay minerals, with varying amounts of carbonate minerals. The geochemistry of loess differs from region to region, depending on source materials, but all loess is very high in SiO2 with lesser amounts of other major elements. Trends in loess downwind from source areas include systematic decreases in thickness and amounts of sand and coarse silt, and increases in amounts of fine silt …

Ethical Issues In Open Source Software, Frances Grodzinsky, Keith W. Miller, Marty J. Wolf

School of Computer Science & Engineering Faculty Publications

In this essay we argue that the current social and ethical structure in the Open Source Software (OSS) Community stem from its roots in academia. The individual developers experience a level of autonomy similar to that of a faculty member. Furthermore, we assert that the Open Source Software Community's social structure demands benevolent leadership. We argue that it is difficult to pass off low quality open source software as high quality software and that the Open Source development model offers strong accountability. Finally, we argue that Open Source Software introduces ethical challenges for universities and the software development community.

Ce-Qual-W2: A Two-Dimensional, Laterally Averaged, Hydrodynamic And Water Quality Model, Version 3.1, Thomas M. Cole, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

CE-QUAL-W2 is a two-dimensional, longitudinal/vertical, hydrodynamic and water quality model. Because the model assumes lateral homogeneity, it is best suited for relatively long and narrow waterbodies exhibiting longitudinal and vertical water quality gradients. The model has been applied to rivers, lakes, reservoirs, estuaries, and combinations thereof.

The application of CE-QUAL-W2 requires knowledge in the following areas: 1. Hydrodynamics 2. Aquatic biology 3. Aquatic chemistry 4. Numerical methods 5. Computers and FORTRAN coding 6. Statistics 7. Data assembly and reconstruction.

Water quality modeling is in many ways an art requiring not only knowledge in these areas but also experience in their …

Published Salinity Information And Wa Farmers. An Investigation Into The Effectiveness Of Current Published Salinity Information, Stephen Lloyd

Agriculture reports

Salinity is one of the greatest environmental threats facing Western Australia. Extension of salinity information to WA farmers is a key process in helping the rural community manage this threat. Published information is an important part of this extension. However, there has been very little research into the use and effectiveness of published salinity information. The aim of this study was to investigate:

• Effectiveness of current salinity information products and services in relation to decision making and practice change by WA farmers;

• Possible improvement in salinity publications to better assist WA farmers in decision making and practice change.

สรุปข่าวและกิจกรรมสิ่งแวดล้อม

Thai Environment

No abstract provided.

สร้างโลกสวย

Thai Environment

No abstract provided.

สิ่งแวดล้อมน่ารู้

Thai Environment

No abstract provided.

Level Of Essentialness Of A Node In Flowcharts And Its Application To Program Testing, Osman Kandara

LSU Doctoral Dissertations

Program testing is important to develop bug free software. A common form of program testing involves selecting test cases which execute (cover) a given set W of statements in the program. In regression testing, W typically forms a small subset of the program. It is often possible to find an alternate small set W so that execution of W' implies execution of W. We develop concepts and algorithms for finding W' as small as possible with the condition that the statements in W' are "close" to those in W in terms of program structure. These concepts generalize the notion of …

Abundance Trends And Environmental Habitat Usage Patterns Of Bottlenose Dolphins (Tursiops Truncatus) In Lower Barataria And Caminada Bays, Louisiana, Cara Edina Miller

LSU Doctoral Dissertations

The paucity of research into the environmental requirements, stock membership, abundance and residency patterns of bottlenose dolphins (Tursiops truncatus) in coastal Louisiana creates difficulty in understanding how local ecosystems and threats (such as fishery interactions, habitat degradation and pollution) affect populations. This study combined fine-scale environmental measurements and photo-identification techniques to describe patterns of habitat usage and abundance of bottlenose dolphins in lower Barataria Basin from June 1999 to May 2002. In addition I investigated the validity and limitations of using mark-recapture models to estimate abundance from cetacean photo-identification data. Bottlenose dolphins were present year-round in a wide range of …

A Comparison Of Life Histories And Ecological Aspects Among Snappers (Pisces: Lutjanidae), Fernando Martinez-Andrade

LSU Doctoral Dissertations

An extensive search for data on life-history and ecological variables was conducted for a representative number of the species within the family Lutjanidae. After creating different databases and standardizing all data, these variables were examined in statistical, correlation and graphic analyses. Additionally, a series of Principal Component Analyses were used to examine patterns among variables. Life-history variables included age at length zero, asymptotic length, maximum length, longevity, asymptotic weight, length at maturity, age at maturity, reproductive life span, growth rate and mortality rate. Ecological variables included latitudinal and vertical distribution, habitat selection (represented by substrate type), and spawning seasons. The …

Biomechanical Reconstruction Of The Appendicular Skeleton In Three North American Jurassic Sauropods, Ray Wilhite

LSU Doctoral Dissertations

Forelimb and hindlimb articulation, reconstructed musculature, and function were examined in Apatosaurus, Diplodocus, and Camarasaurus. A technique was developed using a Microscribe three-dimensional digitizer to capture external morphological data for skeletal reconstruction and determination of taxonomically useful features. The appendicular musculature of Alligator mississippiensis was dissected to determine form, function, origin, and insertion of muscles to aid in reconstruction of sauropod musculature. Contrary to the literature, M. caudofemoralis longus was found to originate primarily from the lateral surfaces of the proximal chevrons instead of the bodies and transverse processes of the caudals, demonstrating that chevron morphology is indicative of the …

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 …

Diffusion Of A Rodlike Virus In Complex Solutions, Randall Charles Cush

LSU Doctoral Dissertations

Entanglement phenomena in concentrated polymer solutions remain an interesting and challenging problem. It is still unclear how entanglement onset affects polymer chain motion at small distance scales. One way to study such motion is to follow the diffusion of a probe particle while increasing the concentration of the polymer. Many such studies have been done using probes ranging from linear and star polymers to various colloidal particles; however, relatively few studies have used rodlike probes. Rodlike probes are potentially more interesting due to the added information that may be gained by following rotational as well as translational diffusion. The anisotropic …

Recent Applications Of Fractional Calculus To Science And Engineering, Lokenath Debnath

School of Mathematical & Statistical Sciences Faculty Publications

This paper deals with recent applications of fractional calculus to dynamical systems in control theory, electrical circuits with fractance, generalized voltage divider, viscoelasticity, fractional-order multipoles in electromagnetism, electrochemistry, tracer in fluid flows, and model of neurons in biology. Special attention is given to numerical computation of fractional derivatives and integrals.

Anisotropy And Its Relation To Liquefaction Resistance Of Granular Material, Isao Ishibashi, Omer F. Capar

Civil & Environmental Engineering Faculty Publications

This research establishes quantitative relationships between soil's anisotropy and liquefaction resistance for granular materials. Uniform medium density (D_r = 50%) sand specimens were prepared using three different sample preparation techniques (air pluviated (AP), moist tamped (NIT), and moist vibrated (MV)) to create different initial soil fabrics. Undrained cyclic triaxial tests were then performed to determine the liquefaction resistance of each soil specimen. On the same specimens in the triaxial cell, vertical and horizontal compression wave velocities and vertical shear wave velocity (V_s) were measured using piezoelectric bender elements. Anisotropic (transversely isotropic) elastic constants of the soil specimens were …

Design And Synthesis Of Constrained Dipeptide Units For Use As Β-Sheet Promoters, Umut Oguz

LSU Doctoral Dissertations

The study of factors promoting beta-sheet formation has recently gained interest due to the suspected involvement of beta-sheets in brain degenerative diseases such as Alzheimer's disease (AD), Creutzfeldt-Jacob disease (CJD) and bovine spongiform encephalopathy. Understanding beta-sheet formation and the factors that stabilize beta-sheet structure may serve as a basis for future drug design. The extended structure of a beta-sheet can be stabilized by constrained amino acid analogs that are pre-organized to adopt the extended conformation. In this dissertation using innovative synthetic organic chemistry methods, two dipeptide units are designed and synthesized that are constrained to form the extended conformation and …

Design And Synthesis Of Handles For Solid-Phase Peptide Synthesis And Convergent Peptide Synthesis, Jose Giraldes

LSU Doctoral Dissertations

The recent popularity of methods for solid-phase peptide synthesis that use the 9-fluorenylmethyloxycarbonyl (Fmoc) group for N^α-amino protection has created a need for compatible anchoring linkages and handles. In an effort to develop mild new methods for use in solid-phase peptide synthesis (SPPS), a new ferrocene containing linker or “handle”, the 1’1-ferrocenyl carboxaldehyde handle was designed, synthesized, characterized and tested. This linker is analogous to those commercially available and developed by Barany. The ferrocenyl amine linker(FAL) releases C-terminal peptide amides upon acidolysis. Since the FAL handle is acid labile it is compatible with Fmoc and N^α-dithiasuccinoyl …

Field Validation Of Bentazon Phytoremediation, Sajida Begum

LSU Master's Theses

Phytoremediation with black willow (Salix nigra) was conducted in 1996 by planting trees at a density of 2000 trees/hectare at BASF Corporation in a shallow groundwater plume containing low levels of bentazon. In this project, the roots, stems,and leaves of the black willow plants were extracted and analyzed to see if bentazon from the ground water was taken up by the plants. Different extraction procedures such as liquid-phase extraction and solid-phase extraction were compared. Final determination using different analytical techniques such as GC-MSD, GC-ECD, and HPLC with UV detection for the isolation and analysis of bentazon residues from the plant …

Solid-Phase Dna Sequencing Reactions Performed In Micro-Capillary Reactors And Solid-Phase Reversible Immobilization In Microfluidic Chips For Purification Of Dye-Labeled Dna Sequencing Fragments, Yichuan Xu

LSU Doctoral Dissertations

The research presented in this dissertation involves micro-capillary reactors for solid phase DNA sequencing, the identification of dye terminator sequencing fragments with time-resolved methods, and purification of dye-labeled DNA fragments using solid- phase reversible immobilization in microfluidic chips. Solid-phase micro-reactors have been prepared for DNA sequencing applications using slab gel electrophoresis. A PCR product was immobilized to the interior wall of a fused-silica capillary tube via a biotin-streptavidin linkage. Solid-phase sequencing was carried out in micro-capillary reactors using a four-lane, single color dye primer chemistry strategy. The read length was found to be 589 bases. The complementary DNA fragments generated …

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 …