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

Physical Sciences and Mathematics Commons™

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

2005

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 4471 - 4500 of 4759

Full-Text Articles in Physical Sciences and Mathematics

Examining The Screening Limit Of Field Effect Devices Via The Metal–Insulator Transition, X. Hong, A. Posadas, C. H. Ahn Jan 2005

Examining The Screening Limit Of Field Effect Devices Via The Metal–Insulator Transition, X. Hong, A. Posadas, C. H. Ahn

Xia Hong Publications

The electronic screening length, the distance over which an electric field is attenuated in a material, imposes a lower physical bound on the lateral size scaling of semiconductor field effect devices. Alternatives will be needed to achieve devices whose characteristic dimensions approach a nanometer. In this work, we demonstrate the atomic-scale nature of screening at high electron densities, using the polarization field of a ferroelectric oxide, Pb(Zr,Ti)O3, to electrostatically modulate the metallicity of ultrathin manganite La1−xSrxMnO3 (LSMO) films near the metal-insulator transition. Within the screening length, the transport characteristics of LSMO vary sharply …

Go to article

Investigation Of The Mechanism Of Polarization Switching In Ferroelectric Capacitors By Three-Dimensional Piezoresponse Force Microscopy, Brian J. Rodriguez, Alexei Gruverman, Angus I. Kingon, Robert J. Nemanich, J. S. Cross Jan 2005

Investigation Of The Mechanism Of Polarization Switching In Ferroelectric Capacitors By Three-Dimensional Piezoresponse Force Microscopy, Brian J. Rodriguez, Alexei Gruverman, Angus I. Kingon, Robert J. Nemanich, J. S. Cross

Alexei Gruverman Publications

A mechanism for the switching behavior of (111)-oriented Pb(Zr, Ti)O3-based 1 × 1.5 μm2 capacitors has been investigated using three-dimensional piezoresponse force microscopy (3D-PFM). A combination of vertical and lateral piezoresponse force microscopy (VPFM and LPFM) has been used to map the out-of-plane and the in-plane components of the polarization. The three-dimensional polarization distribution was reconstructed by quantitative analysis of the PFM amplitude images of poled PZT capacitors while taking into account contrast variations in the PFM phase images. The switching behavior of the capacitors was determined by comparison of the static domain patterns in the same …

Go to article

Experimental Studies Of Light Propagation And Storage In Warm Atomic Gases, H. Gao, Mark A. Rosenberry, J. Wang, Herman Batelaan Jan 2005

Experimental Studies Of Light Propagation And Storage In Warm Atomic Gases, H. Gao, Mark A. Rosenberry, J. Wang, Herman Batelaan

Department of Physics and Astronomy: Faculty Publications

We report on an experimental study of slow pulse propagation and polarization storage of light in an atomic vapour for pulse durations ranging from several μs to 100 μs, for non-zero magnetic fields, for temperatures ranging from 65 to 90 °C and for two different rubidium isotopes. The results confirm the presence of the electromagnetically induced transparency window as predicted by Lukin (1997 Phys. Rev. Lett. 79 2959). We show that time-dependent optical rotation can mask the storage of light signal, and demonstrate storage of light for the 85Rb isotope.

Go to article

Electron Diffraction From Free-Standing, Metal-Coated Transmission Gratings, Glen Gronniger, Brett E. Barwick, Herman Batelaan, Tim Savas, David E. Pritchard, Alex Cronin Jan 2005

Electron Diffraction From Free-Standing, Metal-Coated Transmission Gratings, Glen Gronniger, Brett E. Barwick, Herman Batelaan, Tim Savas, David E. Pritchard, Alex Cronin

Department of Physics and Astronomy: Faculty Publications

Electron diffraction from a free-standing nanofabricated transmission grating was demonstrated, with energies ranging from 125 eV to 25 keV. Observation of 21 diffraction orders highlights the quality of the gratings. The image charge potential due to one electron was measured by rotating the grating. These gratings may pave the way to low-energy electron interferometry.

Go to article

Einstein’S Impact On Optics At The Frontier, Donald Umstadter Jan 2005

Einstein’S Impact On Optics At The Frontier, Donald Umstadter

Donald Umstadter Publications

The seminal contributions made by Einstein a century ago have enabled a new frontier area of science, called high-field science. This research involves the physics of the interactions of matter with electromagnetic fields at its highest levels ever achieved in the laboratory. Besides being of fundamental importance to physics research, the discoveries being made in this area are also leading to a new generation of compact and ultrashort-duration particle accelerators and X-ray light sources, with applications ranging from nuclear fusion to cancer therapy.

Go to article

An Evaluation Of Weather And Disease As Causes Of Decline In Two Populations Of Boreal Toads, Rick D. Scherer, Erin Muths, Barry R. Noon, Paul Stephen Corn Jan 2005

An Evaluation Of Weather And Disease As Causes Of Decline In Two Populations Of Boreal Toads, Rick D. Scherer, Erin Muths, Barry R. Noon, Paul Stephen Corn

United States Geological Survey: Staff Publications

Two populations of boreal toads (Bufo boreas) experienced drastic declines in abundance in the late 1990s. Evidence supported the hypothesis of disease (the chytrid fungus, Batrachochytrium dendrobatidis) as the cause of these declines. but other hypotheses had not been evaluated. We used an 11-year capture-recapture data set to evaluate weather and disease as causes of these declines. We developed sets of mathematical models that reflected hypothesized relationships between several weather variables and annual survival rates of adult males in these populations. In addition, models that reflected the possibility that the declines were caused by an introduced fungus …

Go to article

Fixed Point Theory For Mönch-Type Maps Defined On Closed Subsets Of Fréchet Spaces: The Projective Limit Approach, Ravi P. Agarwal, Donal O'Regan, Jewgeni H. Dshalalow Jan 2005

Fixed Point Theory For Mönch-Type Maps Defined On Closed Subsets Of Fréchet Spaces: The Projective Limit Approach, Ravi P. Agarwal, Donal O'Regan, Jewgeni H. Dshalalow

Mathematics and System Engineering Faculty Publications

New Leray-Schauder alternatives are presented for Mönch-type maps defined between Fréchet spaces. The proof relies on viewing a Fréchet space as the projective limit of a sequence of Banach spaces.

Go to article

Modifications Of Human Βa1/Βa3-Crystallins Include S-Methylation, Glutathiolation, And Truncation, Veniamin N. Lapko, Ronald Cerny, David L. Smith, Jean B. Smith Jan 2005

Modifications Of Human Βa1/Βa3-Crystallins Include S-Methylation, Glutathiolation, And Truncation, Veniamin N. Lapko, Ronald Cerny, David L. Smith, Jean B. Smith

Ronald Cerny Publications

Disulfide bonding of lens crystallins contributes to the aggregation and insolubilization of these proteins that leads to cataract. A high concentration of reduced glutathione is believed to be key in preventing oxidation of crystallin sulfhydryls to form disulfide bonds. This protective role is decreased in aged lenses because of lower glutathione levels, especially in the nucleus. We recently found that human [1]-crystallins undergo S-methylation at exposed cysteine residues, a reaction that may prevent disulfide bonding. We report here that βA1/A3-crystallins are also methylated at specific cysteine residues and are the most heavily methylated of the human lens crystallins. Among the …

Go to article

Scope And Mechanistic Study Of The Ruthenium-Catalyzed Ortho-C−H Bond Activation And Cyclization Reactions Of Arylamines With Terminal Alkynes, Chae S. Yi, Young Yun Jan 2005

Scope And Mechanistic Study Of The Ruthenium-Catalyzed Ortho-C−H Bond Activation And Cyclization Reactions Of Arylamines With Terminal Alkynes, Chae S. Yi, Young Yun

Chemistry Faculty Research and Publications

The cationic ruthenium hydride complex [(PCy3)2(CO)(CH3CN)2RuH]+BF4- was found to be a highly effective catalyst for the C−H bond activation reaction of arylamines and terminal alkynes. The regioselective catalytic synthesis of substituted quinoline and quinoxaline derivatives was achieved from the ortho-C−H bond activation reaction of arylamines and terminal alkynes by using the catalyst Ru3(CO)12/HBF4·OEt2. The normal isotope effect (kCH/kCD = 2.5) was observed for the reaction of C6H5NH2 and C …

Go to article

High Dispersal In A Frog Species Suggest That It Is Vulnerable To Habitat Fragmentation, W. Chris Funk, Allison E. Greene, Paul Stephen Corn, Fred W. Allendorf Jan 2005

High Dispersal In A Frog Species Suggest That It Is Vulnerable To Habitat Fragmentation, W. Chris Funk, Allison E. Greene, Paul Stephen Corn, Fred W. Allendorf

United States Geological Survey: Staff Publications

Global losses of amphibian populations are a major conservation concern and have generated substantial debate over their causes. Habitat fragmentation is considered one important cause of amphibian decline. However, if fragmentation is to be invoked as a mechanism of amphibian decline, it must first be established that dispersal is prevalent among contiguous amphibian populations using formal movement estimators. In contrast, if dispersal is naturally low in amphibians, fragmentation can be disregarded as a cause of amphibian declines and conservation efforts can be focused elsewhere. We examined dispersal rates in Columbia spotted frogs (Rana luteiventris) using capture– recapture analysis …

Go to article

Population Structure Of Columbia Spotted Frogs (Rana Luteiventris) Is Strongly Affected By The Landscape, W. Chris Funk, Michael S. Blouin, Paul Stephen Corn, Bryce A. Maxell, David S. Pilliod, Stephen Amish, Fred W. Allendorf Jan 2005

Population Structure Of Columbia Spotted Frogs (Rana Luteiventris) Is Strongly Affected By The Landscape, W. Chris Funk, Michael S. Blouin, Paul Stephen Corn, Bryce A. Maxell, David S. Pilliod, Stephen Amish, Fred W. Allendorf

United States Geological Survey: Staff Publications

Landscape features such as mountains, rivers, and ecological gradients may strongly affect patterns of dispersal and gene flow among populations and thereby shape population dynamics and evolutionary trajectories. The landscape may have a particularly strong effect on patterns of dispersal and gene flow in amphibians because amphibians are thought to have poor dispersal abilities. We examined genetic variation at six microsatellite loci in Columbia spotted frogs (Rana luteiventris) from 28 breeding ponds in western Montana and Idaho, USA, in order to investigate the effects of landscape structure on patterns of gene flow. We were particularly interested in addressing …

Go to article

Biodiversity And Ecology Of Soil Oribatid Mites (Acari: Oribatida) In The Grassland Habitats Of Eastern Mongolia, Badamdorj Bayartogtokh Jan 2005

Biodiversity And Ecology Of Soil Oribatid Mites (Acari: Oribatida) In The Grassland Habitats Of Eastern Mongolia, Badamdorj Bayartogtokh

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

Composition, abundance, distribution, and diversity of oribatid mite communities were investigated at five study areas in Eastern Mongolia. A total of 88 species of oribatid mites were recorded from the studied areas. The largest number of species (51 spp.) was found in the habitats of river valleys, while the plain steppe which covers the largest area contained the lowest species richness (24 spp.). Three other sub-regions with similar landscape types show approximately the same species richness (39 to 45 spp.), although they are located relatively far from each other. The oribatid mite faunas of all sub-regions were essentially similar to …

Go to article

Roads Diverging In Yellow Woods: New Paths For Ecological And Environmental Anthropology, Sarah Hitchner Jan 2005

Roads Diverging In Yellow Woods: New Paths For Ecological And Environmental Anthropology, Sarah Hitchner

Ecological and Environmental Anthropology (University of Georgia)

Anthropology is at a crossroads; perhaps it always has been. Because it is such a broad discipline, there has always been debate among anthropologists over its role inside and outside of academia. There are often tensions between the paradigms of theory and practice, modernism and postmodernism, constructionism and deconstructionism, scaling up and scaling down, and many other seeming dichotomies that really contain many shades of gray. Anthropology has been called “the most humanistic of the sciences, and the most scientific of the humanities.” We anthropologists should take this phrase as a compliment, and each strive to find our own niche …

Go to article

Review Of Ethnobotany And Conservation Of Biocultural Diversity (Advances In Economic Botany, V. 15) By Thomas J.S. Carlson And Luisa Maffi, Jen Shaffer Jan 2005

Review Of Ethnobotany And Conservation Of Biocultural Diversity (Advances In Economic Botany, V. 15) By Thomas J.S. Carlson And Luisa Maffi, Jen Shaffer

Ecological and Environmental Anthropology (University of Georgia)

A growing recognition of humans as intrinsic parts of ecosystems implies that consideration of human activities and needs is as essential to successful conservation planning, as consideration of other species. Carlson and Maffi organize this volume of papers, given at the Sixteenth International Botanical Congress in 1999, into three sections. Part one focuses on indigenous knowledge and the creation/conservation of biodiversity in the Amazon Basin. Part two examines knowledge and sustainable use of plant resources in the Amazon Basin, sub-Saharan Africa, and Northern Vietnam. The book finishes with a section concerning ethical issues surrounding ethnobiological research and its dissemination – …

Go to article

Acquisition And Evaluation Of Thermodynamic Data For Bieberite-Moorhouseite Equilibria At 0.1 Mpa, I-Ming Chou, Robert Seal Ii Jan 2005

Acquisition And Evaluation Of Thermodynamic Data For Bieberite-Moorhouseite Equilibria At 0.1 Mpa, I-Ming Chou, Robert Seal Ii

United States Geological Survey: Staff Publications

Published estimates for the equilibrium relative humidity (RH) at 25 °C for the reaction: bieberite (CoSO4•7H2O) = moorhouseite (CoSO4•6H2O) + H2O, range from 69.8 to 74.5%. To evaluate these data, the humidity-buffer technique was used to determine equilibrium constants for this reaction between 14 and 43 °C at 0.1 MPa. Reversals along fi ve humidity-buffer curves yield ln K = 18.03–6509.43/T, where K is the equilibrium constant, and T is temperature in K. The derived standard Gibbs free energy of reaction is 9.43 kJ/mol, which agrees well with several previously …

Go to article

Determination Of Goslarite–Bianchite Equilibria By The Humidity-Buffer Technique At 0.1 Mpa, I-Ming Chou, Robert R. Seal Ii Jan 2005

Determination Of Goslarite–Bianchite Equilibria By The Humidity-Buffer Technique At 0.1 Mpa, I-Ming Chou, Robert R. Seal Ii

United States Geological Survey: Staff Publications

Goslarite–bianchite equilibria were determined along four humidity-buffer curves at 0.1 MPa and between 27 and 36 °C. Results, based on tight reversals along each humidity buffer, can be represented by ln K (±0.005)=19.643-7015.38/T, where K is the equilibrium constant and T is temperature in K. Our data are in excellent agreement with several previous vapor-pressure measurements and are consistent with the solubility data reported in the literature. Thermodynamic analysis of these data yields 9.634 (±0.056) kJ mol-1 for the standard Gibbs free energy of reaction, which is in good agreement with the value of 9.658 kJ mol-1 calculated …

Go to article

Geochemistry Of Sulfate Minerals In High- And Low-Temperature Environments: A Tribute To Robert O. Rye, Robert R. Seal Ii, John L. Jambor, Charles N. Alpers Jan 2005

Geochemistry Of Sulfate Minerals In High- And Low-Temperature Environments: A Tribute To Robert O. Rye, Robert R. Seal Ii, John L. Jambor, Charles N. Alpers

United States Geological Survey: Staff Publications

This special issue is a tribute to Robert O. Rye, known as "Bob" to most, in light of his highly productive and ongoing career. Almost all of the papers in this issue are derived from topical sessions on sulfate minerals in hydrothermal and low-temperature environments. The sessions, held at the 2000 Geological Society of America meeting in Reno, NV, and sponsored jointly by the Mineralogical Society of America, the Society of Economic Geologists and the Geochemical Society, included 29 oral and 9 poster presentations. The sessions complemented a short course on the crystallography, geochemistry and environmental significance of sulfate minerals, …

Go to article

Hydrologic Properties Of Coal Beds In The Powder River Basin, Montana I. Geophysical Log Analysis, Roger H. Morin Jan 2005

Hydrologic Properties Of Coal Beds In The Powder River Basin, Montana I. Geophysical Log Analysis, Roger H. Morin

United States Geological Survey: Staff Publications

As part of a multidisciplinary investigation designed to assess the implications of coal-bed methane development on water resources for the Powder River Basin of southeasternMontana, six wells were drilled through Paleocene-age coal beds along a 31 km east–west transect within the TongueRiver drainage basin.Analysis of geophysical logs obtained in thesewells provides insight into the hydrostratigraphic characteristics of the coal and interbedded siliciclastic rocks and their possible interaction with the local stress field.Natural gamma and electrical resistivity logswere effective in distinguishing individual coal beds. Full-waveformsonic logswere used to determine elastic properties of the coal and an attendant estimate of aquifer storage …

Go to article

Negative Correlation Between Porosity And Hydraulic Conductivity In Sand-And-Gravel Aquifers At Cape Cod, Massachusetts, Usa, Roger H. Morin Jan 2005

Negative Correlation Between Porosity And Hydraulic Conductivity In Sand-And-Gravel Aquifers At Cape Cod, Massachusetts, Usa, Roger H. Morin

United States Geological Survey: Staff Publications

Although it may be intuitive to think of the hydraulic conductivity K of unconsolidated, coarse-grained sediments as increasing monotonically with increasing porosity ɸ , studies have documented a negative correlation between these two parameters under certain grain-size distributions and packing arrangements. This is confirmed at two sites on Cape Cod, Massachusetts, USA, where groundwater investigations were conducted in sand-and-gravel aquifers specifically to examine the interdependency of several aquifer properties using measurements from four geophysical well logs. Along with K and ɸ , the electrical resistivity R0 and the natural gamma activity γ of saturated deposits were determined as functions …

Go to article

Comparison Of A Novel Passive Sampler To Standard Water-Column Sampling For Organic Contaminants Associated With Wastewater Effluents Entering A New Jersey Stream, D. A. Alvarez, P. E. Stackelberg, J. D. Petty, J. N. Huckins, E. T. Furlong, S. D. Zaugg, M. T. Meyer Jan 2005

Comparison Of A Novel Passive Sampler To Standard Water-Column Sampling For Organic Contaminants Associated With Wastewater Effluents Entering A New Jersey Stream, D. A. Alvarez, P. E. Stackelberg, J. D. Petty, J. N. Huckins, E. T. Furlong, S. D. Zaugg, M. T. Meyer

United States Geological Survey: Staff Publications

Four water samples collected using standard depth and width water-column sampling methodology were compared to an innovative passive, in situ, sampler (the polar organic chemical integrative sampler or POCIS) for the detection of 96 organic wastewater-related contaminants (OWCs) in a stream that receives agricultural, municipal, and industrial wastewaters. Thirty-two OWCs were identified in POCIS extracts whereas 9–24 were identified in individual water-column samples demonstrating the utility of POCIS for identifying contaminants whose occurrence are transient or whose concentrations are below routine analytical detection limits. Overall, 10 OWCs were identified exclusively in the POCIS extracts and only six solely identified in …

Go to article

Selenium Impactson Razorback Sucker, Colorado River, Colorado I. Adults, Steven J. Hamilton, Kathy M. Holley, Kevin J. Buhl, Fern A. Bullard, L. Ken Weston, Susan F. Mcdonald Jan 2005

Selenium Impactson Razorback Sucker, Colorado River, Colorado I. Adults, Steven J. Hamilton, Kathy M. Holley, Kevin J. Buhl, Fern A. Bullard, L. Ken Weston, Susan F. Mcdonald

United States Geological Survey: Staff Publications

Adult razorback sucker (Xyrauchen texanus) were exposed to various selenium concentrations in ponds and isolated river channels of the Colorado River near Grand Junction, CO, to determine effectson their growth and residue accumulation over an 11-month period. Adults at Horsethief ponds were fed a commercial diet, whereas fish at Adobe Creek channel and North Pond foraged on natural food items. Selenium concentrations at Horsethief were 2.2 μg/L in water, 0.1–1.4 μg/g in sediment, and 2.3–3.1 μg/g in food organisms (1.1 μg/g in commercial fish food), at Adobe Creek were 3.8 μg/L in water, 0.5–2.1 μg/g in sediment, and …

Go to article

Amphibian Research And Monitoring Initiative (Armi): A Successful Start To A National Program In The United States, Erin Muths, Robin E. Jung, Larissa L. Bailey, Michael J. Adams, P. Stephen Corn, C. Kenneth Dodd Jr., Gary M. Fellers, Walter J. Sadinski, Cecil R. Schwalbe, Susan C. Walls, Robert N. Fisher, Alisa L. Gallant, William A. Battaglin, D. Earl Green Jan 2005

Amphibian Research And Monitoring Initiative (Armi): A Successful Start To A National Program In The United States, Erin Muths, Robin E. Jung, Larissa L. Bailey, Michael J. Adams, P. Stephen Corn, C. Kenneth Dodd Jr., Gary M. Fellers, Walter J. Sadinski, Cecil R. Schwalbe, Susan C. Walls, Robert N. Fisher, Alisa L. Gallant, William A. Battaglin, D. Earl Green

United States Geological Survey: Staff Publications

Most research to assess amphibian declines has focused on local-scale projects on one or a few species. The Amphibian Research and Monitoring Initiative (ARMI) is a national program in the United States mandated by congressional directive and implemented by the U.S. Department of the Interior (specifically the U.S. Geological Survey, USGS). Program goals are to monitor changes in populations of amphibians across U.S. Department of the Interior lands and to address research questions related to amphibian declines using a hierarchical framework of base-, mid- and apex-level monitoring sites. ARMI is currently monitoring 83 amphibian species (29% of species in the …

Go to article

A Multilocus Population Genetic Survey Of The Greater Sage-Grouse Across Their Range, S. J. Oyler-Mccance, S.E. Taylor, T. W. Quinn Jan 2005

A Multilocus Population Genetic Survey Of The Greater Sage-Grouse Across Their Range, S. J. Oyler-Mccance, S.E. Taylor, T. W. Quinn

United States Geological Survey: Staff Publications

The distribution and abundance of the greater sage-grouse (Centrocercus urophasianus) have declined dramatically, and as a result the species has become the focus of conservation efforts. We conducted a range-wide genetic survey of the species which included 46 populations and over 1000 individuals using both mitochondria1 sequence data and data from seven nuclear microsatellites. Nested clade and STRUCTURE analyses revealed that, in general, the greater sage-grouse populations follow an isolation-by-distance model of restricted gene flow. This suggests that movements of the greater sage-grouse are typically among neighboring populations and not across the species, range. This may have important …

Go to article

Participant Observations On Environmental And Social Eff Ect S Of The Conservation Reserve Program: Results Of A National Survey, Arthur W. Alen Jan 2005

Participant Observations On Environmental And Social Eff Ect S Of The Conservation Reserve Program: Results Of A National Survey, Arthur W. Alen

United States Geological Survey: Staff Publications

A national survey of Conservation Reserve Program (CRP) contractees was completed to obtain information about environmental and social effects of the program on participants, farms, and communities. Over 75% of respondents believed CRP benefits to wildlife were important. Seventy-three percent of respondents observed increased numbers of wildlife associated with CRP lands. A majority of respondents (82%) believed the amount of assistance furnished by the U.S. Department of Agriculture related to planning and maintaining wildlife habitat associated with CRP lands was appropriate. The majority of respondents reported CRP benefits, including increased quality of surface and ground waters, improved air quality, control …

Go to article

Transport Of Chemical And Microbial Compounds From Known Wastewater Discharges: Potential For Use As Indicators Of Human Fecal Contamination, Susan Glassmeyer, Edward Furlong, Dana Kolpin, Jeffrey Cahill, Steven Zaugg, Stephen Werner, Michael Meyer, David Kryak Jan 2005

Transport Of Chemical And Microbial Compounds From Known Wastewater Discharges: Potential For Use As Indicators Of Human Fecal Contamination, Susan Glassmeyer, Edward Furlong, Dana Kolpin, Jeffrey Cahill, Steven Zaugg, Stephen Werner, Michael Meyer, David Kryak

United States Geological Survey: Staff Publications

The quality of drinking and recreational water is currently (2005) determined using indicator bacteria. However, the culture tests used to analyze for these bacteria require a long time to complete and do not discriminate between human and animal fecal material sources. One complementary approach is to use chemicals found in human wastewater, which would have the advantages of (1) potentially shorter analysis times than the bacterial culture tests and (2) being selected for human-source specificity. At 10 locations, water samples were collected upstream and at two successive points downstream from a waste-waster treatment plant (WWTP); a treated effluent sample was …

Go to article

Characterization Of Waste Rock Associated With Acid Drainage At The Penn Mine, California, By Ground-Based Visible To Short-Wave Infrared Reflectance Spectroscopy Assisted By Digital Mapping, Irene C. Montero S., George H. Brimhall, Charles N. Alpers, Gregg A. Swayze Jan 2005

Characterization Of Waste Rock Associated With Acid Drainage At The Penn Mine, California, By Ground-Based Visible To Short-Wave Infrared Reflectance Spectroscopy Assisted By Digital Mapping, Irene C. Montero S., George H. Brimhall, Charles N. Alpers, Gregg A. Swayze

United States Geological Survey: Staff Publications

Prior to remediation at the abandoned Cu–Zn Penn Mine in the Foothills massive sulfide belt of the Sierra Nevada, CA, acid mine drainage (AMD) was created, in part, by the subaerial oxidation of sulfides exposed on several waste piles. To support remediation efforts, a mineralogical study of the waste piles was undertaken by acquiring reflectance spectra (measured in the visible to short-wave infrared range of light (0.35–2.5 Am) using a portable, digitally integrated pen tablet PC mapping system with differential global positioning system and laser rangefinder support. Analysis of the spectral data made use of a continuum removal and band-shape …

Go to article

Serologic Evidence Of Exposure Of Wild Mammals To Flaviviruses In The Central And Eastern United States, J. Jeffrey Root, Jeffrey S. Hall, Robert G. Mclean, Nicole L. Marlenee, Barry J. Beaty, Justin Gansowski, Larry Clark Jan 2005

Serologic Evidence Of Exposure Of Wild Mammals To Flaviviruses In The Central And Eastern United States, J. Jeffrey Root, Jeffrey S. Hall, Robert G. Mclean, Nicole L. Marlenee, Barry J. Beaty, Justin Gansowski, Larry Clark

United States Department of Agriculture Wildlife Services: Staff Publications

Serosurveys were conducted to obtain flavivirus and West Nile virus (WNV) seroprevalence data from mammals. Sera from 513 small- and medium-sized mammals collected during late summer and fall 2003 from Colorado, Louisiana, New York, Ohio, and Pennsylvania were screened for flavivirus-specific antibodies. Sera samples containing antibody to flaviviruses were screened for WNV-specific antibodies by epitope-blocking enzyme-linked immunosorbent assays and confirmed with plaque reduction neutralization tests. Prevalence of WNV antibodies among study sites ranged from 0% to 42.8% among the mammal communities sampled. High prevalence rates for WNV were noted among raccoons (100%, with a very small sample size, N = …

Go to article

Temperature Dependence Of The Magnetism In Fe/Cu(001), Axel Enders, D. Repetto, D. Peterka, Klaus Kern Jan 2005

Temperature Dependence Of The Magnetism In Fe/Cu(001), Axel Enders, D. Repetto, D. Peterka, Klaus Kern

Axel Enders Publications

The correlation between morphology and magnetism of ultrathin epitaxial films is investigated by a combined study of variable temperature scanning tunneling microscopy, magneto-optical Kerr effect measurements, and Kerr microscopy under ultrahigh vacuum condition. The magnetization reversal of the films was studied as a function of temperature by imaging the propagation of Bloch domain walls in situ. It is demonstrated on the example of fcc Fe films grown at 120 K on Cu(001) that changes in the morphology of the films during annealing are directly reflected in modified magnetic properties. Competing pinning mechanisms for the domain wall propagation are identified. The …

Go to article

Bibliography Of Studies In Electron Transmission Spectroscopy, Paul Burrow Jan 2005

Bibliography Of Studies In Electron Transmission Spectroscopy, Paul Burrow

Paul Burrow Publications

A variety of techniques can be used to locate temporary negative ion states in atoms and molecules. One of the most efficient methods passes an electron beam through a gas cell and observes structure appearing in the attenuated “transmitted” electron current as a function of the electron energy. In 1971 L. Sanche and G.J. Schulz introduced a scheme whereby the derivative with respect to energy of the transmitted current was measured. Combining this with the trochoidal electron monochromator devised by A. Stamatovic and G.J. Schulz in 1968 produced a compact, sensitive and easily used apparatus for the detection of short-lived …

Go to article

Dynamics Of Filament Formation In A Kerr Medium (With Erratum), Martin Centurion, Ye Pu, Mankei Tsang, Demetri Psaltis Jan 2005

Dynamics Of Filament Formation In A Kerr Medium (With Erratum), Martin Centurion, Ye Pu, Mankei Tsang, Demetri Psaltis

Martin Centurion Publications

We have studied the large-scale beam breakup and filamentation of femtosecond pulses in a Kerr medium. We have experimentally monitored the formation of stable light filaments, conical emission, and interactions between filaments. Three major stages lead to the formation of stable light filaments: First the beam breaks up into a pattern of connected lines (constellation), then filaments form on the constellations, and finally the filaments release a fraction of their energy through conical emission. We observed a phase transition to a faster filamentation rate at the onset of conical emission. We attribute this to the interaction of conical emissions with …

Go to article

First Prev Next Last