Physical Sciences and Mathematics Commons^™

Holocene Multidecadal And Multicentennial Droughts Affecting Northern California And Nevada, Larry Benson, Michaele Kashgarian, Robert Rye, Steve Lund, Fred Paillet, Joseph Smoot, Cynthia Kester, Scott Mensing, Dave Meko, Susan Landström

United States Geological Survey: Staff Publications

Continuous, high-resolution δ¹⁸O records from cored sediments of Pyramid Lake, Nevada, indicate that oscillations in the hydrologic balance occurred, on average, about every 150 years (yr) during the past 7630 calendar years (cal yr). The records are not stationary; during the past 2740 yr, drought durations ranged from 20 to 100 yr and intervals between droughts ranged from 80 to 230 yr. Comparison of tree-ring-based reconstructions of climate change for the past 1200 yr from the Sierra Nevada and the El Malpais region of northwest New Mexico indicates that severe droughts associated with Anasazi withdrawal from Chaco Canyon …

Bedform Movement Recorded By Sequential Single-Beam Surveys In Tidal Rivers, R. L. Dinehart

United States Geological Survey: Staff Publications

A portable system for bedform-mapping was evaluated in the delta of the lower Sacramento and San Joaquin Rivers, California, from 1998 to 2000.  Bedform profiles were surveyed with a two-person crew using an array of four single-beam transducers on boats about 6 m in length.  Methods for processing the bedform profiles into maps with geographic coordinates were developed for spreadsheet programs and surface-contouring software.  Straight reaches were surveyed every few days or weeks to determine locations of sand deposition, net transport directions, flow thresholds for bedform regimes, and bedform transport rates.  In one channel of unidirectional flow, the portable system …

Overview Of Hydrocarbon Production, Consumption, Reserves And Potential, At World And Local Scales, Mitchell E. Henry, Debra Higley

United States Geological Survey: Staff Publications

Hydrocarbon (oil and gas) production and consumption, along with remaining resources, are irregularly distributed across the world and within countries. Daily world hydrocarbon production, in 1999, was 72.6 million barrels of oil (mbo) and 232 billion cubic feet of gas (bcfg). Daily average production in 1999, for North America, was 14 mbo and 71.7 bcfg, and, for the United States, it was 8.1 mbo and 50.9 bcfg. North American average daily consumption for 1999 was 23.4 mbo and 71.5 bcfg. The United States produced 42 percent of the oil and 85 percent of the gas it consumed in 1999. Onshore …

West Nile Virus: A Threat To North American Avian Species, Robert G. Mclean

United States Geological Survey: Staff Publications

West Nile virus (WNV) was introduced into the United States (US), specifically in New York City (NYC), in 1999; this translocation represented a major shift out of its normal geographical distribution of Africa, the Middle East, Europe and the western parts of Asia (Center for Disease Control 1999a). The route or method of entry into the US is still unknown. WNV is in the genus Flavivirus, the family Flaviviridae and is closely related to some other viruses in this family, such as Japanese encephalitis virus in Southeast Asia, Murray Valley encephalitis virus in Australia and St. Louis encephalitis (SLE) …

A Procedural Evaluation Of An Analytic-Deliberative Process: The Columbia River Comprehensive Impact Assessment, Aimee Guglielmo Kinney, Thomas M. Leschine

United States Army Corps of Engineers, Omaha District

The U.S. Department of Energy's Columbia River Comprehensive Impact Assessment (CRCIA) was an ambitious attempt to direct its cleanup of the Hanford Nuclear Reservation toward the most significant risks to the Columbia River resulting from past plutonium production. DOE's approach was uncommonly open, including tribal, regulatory agency, and other Hanford interest group representatives on the board that was to develop the assessment approach. The CRCIA process had attributes of the ``analytic-deliberative'' process for risk assessment recommended by the National Research Council. Nevertheless, differences between the DOE and other participants over what was meant by the term ``comprehensive'' in the group's …

The Last Interglacial Period On The Pacific Coast Of North America: Timing And Paleoclimate, Daniel R. Muhs, Kathleen R. Simmons, George L. Kennedy, Thomas K. Rockwell

United States Geological Survey: Staff Publications

New, high-precision U-series ages of solitary corals (Balanophyllia elegans) coupled with molluscan faunal data from marine terraces on the Pacific Coast of North America yield information about the timing and warmth of the last interglacial sea-level highstand. Balanophyllia elegans takes up U in isotopic equilibrium with seawater during growth and shortly after death. Corals from the second terrace on San Clemente Island (offshore southern California), the third terrace on Punta Banda (on the Pacific Coast of northern Baja California), and the Discovery Point Formation on Isla de Guadalupe (in the Pacific Ocean offshore Baja California) date to the …

Last Interglacial Climates, George J. Kukla, Michael L. Bender, Jacques-Louis De Beaulieu, Gerard Bond, Wallace S. Broecker, Piet Cleveringa, Joyce E. Gavin, Timothy D. Herbert, John Imbrie, Jean Jouzel, Lloyd D. Keigwin, Karen-Luise Knudsen, Jerry F. Mcmanus, Josef Merkt, Daniel R. Muhs, Helmut Muller, Richard Z. Poore, Stephen C. Porter, Guy Seret, Nicholas J. Shackleton, Charles Turner, Polychronis C. Tzedakis, Isaac J. Winograd

United States Geological Survey: Staff Publications

The last interglacial, commonly understood as an interval with climate as warm or warmer than today, is represented by marine isotope stage (MIS) 5e, which is a proxy record of low global ice volume and high sea level. It is arbitrarily dated to begin at approximately 130,000 yr B.P. and end at 116,000 yr B.P. with the onset of the early glacial unit MIS 5d. The age of the stage is determined by correlation to uranium–thorium dates of raised coral reefs. The most detailed proxy record of interglacial climate is found in the Vostok ice core where the temperature reached …

Evidence For The Timing And Duration Of The Last Interglacial Period From High-Precision Uranium-Series Ages Of Corals On Tectonically Stable Coastlines, Daniel R. Muhs

United States Geological Survey: Staff Publications

The last interglacial period has a timing and duration that can be estimated from U-series dating of emergent, coral-bearing deposits on tectonically stable coastlines. High-precision dating from Bermuda, the Bahamas, Hawaii, and Australia suggests that the last interglacial period had a sea level at least as high as present from ~128,000 to 116,000 yr B.P. Sea level reached a near-present level more quickly after the close of the penultimate glacial period than at the close of the last glacial period and the duration of high sea level is longer than that implied by the deep-sea record.

Timing And Warmth Of The Last Interglacial Period: New U-Series Evidence From Hawaii And Bermuda And A New Fossil Compilation For North America, Daniel R. Muhs, Kathleen R. Simmons, Bree Steinke

United States Geological Survey: Staff Publications

The timing and duration of the Last Interglacial period have been controversial, with some studies suggesting a relatively short duration that is orbitally forced and others suggesting a long duration that is at most only partly related to orbital forcing. New, high-precison thermal ionization mass spectrometric (TIMS) U-series ages of Last Interglacial corals from Hawaii and Bermuda test these competing hypotheses. Waimanalo Formation corals from slowly uplifting Oahu, Hawaii range in age from ~ 134 to ~ 113 ka, with most ages between ~ 125 and ~ 115 ka. Combined with published U-series ages from nearby Lanai, the data suggest …

Radiocarbon Dating, Chronologic Framework, And Changes In Accumulation Rates Of Holocene Estuarine Sediments From Chesapeake Bay, Steven M. Colman, Pattie C. Baucom, John F. Bratton, Thomas M. Cronin, John P. Mcgeehin, Debra Willard, Andrew R. Zimmerman, Peter R. Vogt

United States Geological Survey: Staff Publications

Rapidly accumulating Holocene sediments in estuaries commonly are difficult to sample and date. In Chesapeake Bay, we obtained sediment cores as much as 20min length and used numerous radiocarbon ages measured by accelerator mass spectrometry methods to provide the first detailed chronologies of Holocene sediment accumulation in the bay. Carbon in these sediments is a complex mixture of materials from a variety of sources. Analyses of different components of the sediments show that total organic carbon ages are largely unreliable, because much of the carbon (including coal) has been transported to the bay from upstream sources and is older than …

Probability Of Nitrate Contamination Of Recently Recharged Groundwaters In The Conterminous United States, Bernard Nolan, Kerie Hitt, Barbara Ruddy

United States Geological Survey: Staff Publications

A new logistic regression (LR) model was used to predict the probability of nitrate contamination exceeding 4 mg/L in predominantly shallow, recently recharged groundwaters of the United States. The new model contains variables representing (1) N fertilizer loading (p < 0.001), (2) percent cropland-pasture (p < 0.001), (3) natural log of human population density (p < 0.001), (4) percent well-drained soils (p < 0.001), (5) depth to the seasonally high water table (p < 0.001), and (6) presence or absence of unconsolidated sand and gravel aquifers (p =0.002). Observed and average predicted probabilities associated with deciles of risk are well correlated (r² = 0.875), indicating that the LR model fits the data well. The likelihood of nitrate contamination is greater in areas with high N loading and well-drained surficial soils over unconsolidated sand and gravels. The LR model correctly predicted the status of nitrate contamination in 75% of wells in a validation data set. Considering all wells used in both calibration and …

Safety Of Brucella Abortus Strain Rb51 Vaccine In Non-Target Ungulates And Coyotes, Terry J. Kreeger, Thomas J. Deliberto, Steven C. Olsen, William H. Edwards, Walter E. Cook

United States Department of Agriculture Wildlife Services: Staff Publications

Brucellosis is endemic in free-ranging elk (Cervus elaphus) and bison (Bison bison) in the Greater Yellowstone Area (GYA; USA). It is possible that an oral brucellosis vaccine could be developed and disseminated in the GYA to reduce disease transmission. Should this occur, non-target species other than elk and bison may come in contact with the vaccine resulting in morbidity or mortality. To assess biosafety, bighorn sheep (Ovis canadensis; n=10), pronghorn (Antilocapra americana; n=9), mule deer (Odocoileus hemionus; n=11), moose (Alces alces shirasi; n=10), and …

Holographic Recording Of Fast Events On A Ccd Camera, Zhiwen Liu, Martin Centurion, George Panotopoulos, John Hong, Demetri Psaltis

Martin Centurion Publications

We report on holographic recording of nanosecond events on a conventional CCD camera. Three frames of an air-discharge event, with resolution of 5.9 ns and frame interval of 12 ns, are recorded in a single CCD frame. Each individual frame is reconstructed by digital filtering of the CCD frame, since successively recorded holograms are centered at different carrier frequencies in the spatial frequency domain.

Structural Transition In (C60)N Clusters, W. Branz, N. Malinowski, Axel Enders, T. P. Martin

Axel Enders Publications

The structure of (C₆₀) _n clusters (n = 1– 150) was investigated by heating them to definite temperatures in a helium bath (heating cell) with subsequent characterization in a time-of-flight mass spectrometer. The intensity anomalies in the resulting mass spectra reflect particularly stable configurations that resisted evaporation. However, the set of enhanced peaks (magic numbers) turned out to be temperature dependent. Clusters heated to a moderate temperature of 490 K yielded mass spectra indicating the presence of icosahedral structures that can be characterized by a set of unusually strong peaks, namely n = 13, 19, 23, 26, …

Unifying Lectures, Recitations & Laboratories As A Part Of The Humanized Physics Project, Vicki L. Plano Clark, Robert G. Fuller

Robert G. Fuller Publications

As a part of our work in the Humanized Physics Project, we have made the content of the physics laboratories the keystone of our physics content coverage. After having selected an appropriate human application of physics for the laboratory each week, we have shaped the lecture, recitation and homework assignments to support the laboratory. Our poster will provide examples from both semesters of our general physics course.

Cross Section And Heavy Quark Composition Of Γ+Μ Events Produced In Pp̅ Collisions, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We present a measurement of the cross section and the first measurement of the heavy flavor content of associated direct photon + muon events produced in hadronic collisions. These measurements come from a sample of 1.8 TeV pp̅ collisions recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily due to the Compton scattering process cg→cγ , with the final-state charm quark producing a muon. The cross section for events with a photon transverse momentum between 12 and 40 GeV/c is measured to be 46.8±6.3±7.5 pb, which is two standard deviations below the …

Neutron Powder Diffraction Studies Of The La0.65Pb0.35Mno3 Perovskite, Camelia Borca, Shireen Adenwalla, Sy-Hwang Liou, Q.L. Xu, J. L. Robertson, Peter A. Dowben

Peter Dowben Publications

The structure of La_0.65Pb_0.35MnO₃ has been studied by neutron powder diffraction. From the temperature dependence of the lattice parameters, we observe that La_0.65Pb_0.35MnO₃ remains single phase in the temperature interval from 25 to 400 K, with a rhombohedral (R3c) structure. The collinear Mn spins suffer a thermally driven reorientation transition close to the Curie temperature, as obtained from powder samples (using neutron diffraction) and from thin films [using ferromagnetic resonance (FMR)]. The reorientation transition may indicate the presence of local Jahn–Teller (JT) lattice distortions, which are prevented from …

New Amphicyonid Carnivorans (Mammalia, Daphoeninae) From The Early Miocene Of Southeastern Wyoming, Robert M. Hunt Jr.

Department of Earth and Atmospheric Sciences: Faculty Publications

Latest Arikareean sediments of the upper Arikaree Group in southeastern Wyoming produced rare fossils of large, early Miocene amphicyonid carnivorans for field parties of the Frick Laboratory, American Museum, from 1932 to 1940. Recent geologic field investigations, including mapping, have discovered additional remains of these carnivorans, clarifying their geographic and stratigraphic distribution, and permitting a more informed description of the earlier collections. These carnivorans come from tuffaceous sandstones of the Upper Harrison beds, the terminal formation-rank unit of the Arikaree Group in southeastern Wyoming. A large species of the amphicyonid Daphoenodon (D. falkenbachi, n. sp.) occurs in northern …

Intercontinental Migration Of Neogene Amphicyonids (Mammalia, Carnivora): Appearance Of The Eurasian Beardog Ysengrinia In North America, Robert M. Hunt Jr.

Department of Earth and Atmospheric Sciences: Faculty Publications

At the beginning of the Neogene a remarkable faunal turnover occurred within the North American carnivore community. The dominant larger Oligocene carnivores (creodonts, nimravid cats, the amphicyonid Daphoenus) became extinct during the late Oligocene and were replaced in the early Miocene by amphicyonine amphicyonids and hemicyonine ursids that entered North America from Eurasia. During a five million-year interval from ~23 to 18 Ma, large amphicyonines appear in late Arikareean and early Hemingfordian faunas of the North American midcontinent. Although most fossils are from western Nebraska and southeastern Wyoming, occurrences of amphicyonines at several sites in the eastern United States …

Concordant Paleolatitudes For Neoproterozoic Ophiolitic Rocks Of The Trinity Complex, Klamath Mountains, California, Edward A. Mankinen, Nancy Lindsley-Griffin, John R. Griffin

Department of Earth and Atmospheric Sciences: Faculty Publications

New paleomagnetic results from the eastern Klamath Mountains of northern California show that Neoproterozoic rocks of the Trinity ophiolitic complex and overlying Middle Devonian volcanic rocks are latitudinally concordant with cratonal North America. Combining paleomagnetic data with regional geologic and faunal evidence suggests that the Trinity Complex and related terranes of the eastern Klamath plate were linked in some fashion to the North American craton throughout that time, but that distance between them may have varied considerably. A possible model that is consistent with our paleomagnetic results and the geologic evidence is that the Trinity Complex formed and migrated parallel …

A Set Of New Sea Ice Feature Descriptors For Sar Images, Leen-Kiat Soh

School of Computing: Technical Reports

In this paper, we present a set of algorithms for describing sea ice features in SAR images. These algorithms we have implemented and incorporated in the ARKTOS software package, an intelligent sea ice classification. These algorithms have unique characteristics. Some are extensions or adaptations of existing image processing techniques to the specific problem domain of satellite sea ice classification, while some are innovative designs, inspired by the aforementioned problem domain. These feature descriptors may be generalized to other remote sensing applications.

Two Algorithms For Shaped-Based Porosity Measures, Leen-Kiat Soh

School of Computing: Technical Reports

In this paper, we present two algorithms for shape-based porosity measures. Specifically, we describe two innovative attributes called perimeter porosity and area porosity as feature descriptors. Perimeter porosity refers to how “porous” or “weak” an image object is, while area porosity determines the degree of “branchiness” of an object. We show the applicability of the two measures through a SAR sea ice image classification example.

An Analytical Model For Virtual Topology Reconfiguration In Optical Networks And A Case Study, Xi Yang, Byrav Ramamurthy

School of Computing: Conference and Workshop Papers

An analytical model for Virtual Topology Reconfiguration (VTR) in optical networks is developed. It aims at the optical networks with a circuit-based data plane and an IPlike control plane. By identifying and analyzing the important factors impacting the network performance due to VTR operations on both planes, we can compare the benefits and penalties of different VTR algorithms and policies. The best VTR scenario can be adaptively chosen from a set of such algorithms and policies according to the real-time network situations. For this purpose, a cost model integrating all these factors is created to provide a comparison criterion independent …

Dynamic Routing In Translucent Wdm Optical Networks, Xi Yang, Byrav Ramamurthy

School of Computing: Conference and Workshop Papers

Translucent WDM optical networks use sparse placement of regenerators to overcome the impairments and wavelength contention introduced by fully transparent networks, and achieve a performance close to fully opaque networks with much less cost. Our previous study proved the feasibility of translucent networks using sparse regeneration technique. We addressed the placement of regenerators based on static schemes allowing only fixed number of regenerators at fixed locations. This paper furthers the study by proposing a suite of dynamical routing schemes. Dynamic allocation, advertisement and discovery of regeneration resources are proposed to support sharing transmitters and receivers between regeneration and access functions. …

Creep Critters From Nebraska's Past, Roger K. Pabian

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Dynamic Traffic Grooming Algorithms For Reconfigurable Sonet Over Wdm Networks, Shu Zhang, Byrav Ramamurthy

School of Computing: Conference and Workshop Papers

The emergence of Wavelength Division Multiplexing (WDM) technology provides the capability for increasing the bandwidth of Synchronous Optical Network (SONET) rings by grooming low-speed traffic streams onto different high-speed wavelength channels. Since the cost of SONET add-drop multiplexers (SADM) at each node dominates the total cost of these networks, how to assign the wavelength, groom in the traffic and bypass the traffic through the intermediate nodes has received a lot of attention from researchers recently.

Constraint Modeling And Reformulation In The Context Of Academic Task Assignment, Robert Glaubius, Berthe Y. Choueiry

School of Computing: Conference and Workshop Papers

We discuss the modeling and reformulation of a resource allocation problem, the assignment of graduate teaching assistants (GTAs) to courses. Our research contributes the following:

• Formulation of the GTA assignment problem as a nonbinary CSP.

• Design of a new convention for consistency checking to deal with over-constrained problem.

• Definition of a new network-decomposable nonbinary confinement constraint.

• Evaluation of the reformulation of confinement and equality constraints on 3 real-world data sets.

Constraint Modeling And Reformulation In The Context Of Academic Task Assignment, Robert Glaubius, Berthe Y. Choueiry

School of Computing: Conference and Workshop Papers

We discuss the modeling and reformulation of a resource allocation problem, the assignment of Graduate Teaching Assistants to courses in the University of Nebraska-Lincoln Computer Science Department. We formulate this problem as a non-binary Constraint Satisfaction Problem (CSP) and provide a new convention for consistency checking to deal with the over-constraindness of the problem and the practical requirement of our application. We introduce a new decomposable non-binary constraint, which we call confinement constraint, and describe its relevance in practical requirements of our application. We introduce an new decomposable non-binary constraint, which we call confinement constraint, and describe its relevance in …

Groundwater-Level Changes In Nebraska-Spring 2000 To Spring 2001/Groundwater-Level Changes In Nebraska-Predevelopment To Spring 2001, Conservation Survey Division

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

A Novel Method To Improve The Test Efficiency Of Vlsi Tests, Hailong Cui, Sharad C. Seth, Shashank K. Mehta

School of Computing: Conference and Workshop Papers

This paper considers reducing the cost of test application by permuting test vectors to improve their defect coverage. Algorithms for test reordering are developed with the goal of minimizing the test cost. Best and worst case bounds are established for the performance of a reordered sequence compared to the original sequence of test application. SEMATECH test data and simulation results are used throughout to illustrate the ideas.