Physical Sciences and Mathematics Commons^™

Erratum: Dynamics Of Filament Formation In A Kerr Medium [Phys Rev. A 71, 063811 (2005)], Martin Centurion, Ye Pu, Mankei Tsang, Demetri Psaltis

Martin Centurion Publications

We have found an error in this paper -- [Phys Rev. A 71, 063811 (2005)]. In our calculation of the intensity threshold for breakdown in CS₂ we erroneously used the ionization energy of molecular CS₂ (10.08 eV). The correct value should be 3.3 eV, the band gap energy of liquid CS₂ . Using the band gap energy, nonlinear absorption will be a three-photon process, and the calculated breakdown threshold becomes 8.5 × 10¹¹ W/cm² (as opposed to the value of 2×10¹³ W/cm² reported previously). Multiphoton absorption and plasma defocusing could then become significant …

The Geoprofile Metadata, Exposure Of Instruments, And Measurement Bias In Climatic Record Revisited, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Impacts Of Irrigation On 20th Century Temperature In The Northern Great Plains, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Coupling Between Primary Terrestrial Succession And The Trophic Development Of Lakes At Glacier Bay, Alaska, D. R. Engstrom, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

The natural eutrophication of lakes is still an accepted concept in limnology, arising as it does from the earliest efforts to classify lakes and place them in an evolutionary sequence. Recent studies of newly formed lakes at Glacier Bay, Alaska, only partially support this idea, and suggest more variable trends in lake trophic development which are under local (catchment-level) control. Here we use sediment cores from several lakes in Glacier Bay National Park to examine the relationship between successional changes in catchment vegetation and trends in water-column nitrogen (a limiting nutrient) and lake primary production. Terrestrial succession at Glacier Bay …

Isopiestic Measurement Of The Osmotic Coefficients Of Aqueous {Xh2So4 + (1−X)Fe2(So4)3} Solutions At 298.15 And 323.15 K, Mariano Velazquez-Rivera, Donald Palmer, Richard Kettler

Department of Earth and Atmospheric Sciences: Faculty Publications

This study measures the osmotic coefficients of {xH₂SO₄ +(1−x)Fe₂ (SO₄)₃}(aq) solutions at 298.15 and 323.15 K that have ionic strengths as great as 19.3 mol•kg^-1, using the isopiestic method. Experiments utilized both aqueous NaCl and H₂SO₄ as reference solutions. Equilibrium values of the osmotic coefficient obtained using the two different reference solutions were in satisfactory internal agreement. The solutions follow generally the Zdanovskii empirical linear relationship and yield values of a_w for the Fe₂ (SO₄)₃–H₂O binary system at 298.15 …

Reconstructing Sea-Level Change From The Internal Architecture Of Stromatolite Reefs: An Example From The Mesoproterozoic Sulky Formation, Dismal Lakes Group, Arctic Canada, L C. Kah, Julie K. Bartley, Tracy D. Frank, Timothy W. Lyons

Department of Earth and Atmospheric Sciences: Faculty Publications

The Mesoproterozoic Dismal Lakes Group, arctic Canada, contains a relatively thin, yet regionally extensive stromatolitic reef complex that developed subtidally during a major transgression, shoaled to sea level, and was overlain by intertidal to supratidal carbonate and evaporite strata. The September Lake reef complex exhibits a complex internal architecture that records the interaction between stromatolite growth and changes in accommodation space derived from both higher order (4th- or 5th-order, parasequence-scale) changes in sea level and the variable bathymetry of the sea floor. Reef growth, which was initiated during three sea-level cycles, records progressive marine transgression over depositional lows that were …

Advances In Data Modeling Research, G. Allen, A. Bajaj, V. Khatri, S. Ram, Keng Siau

Research Collection School Of Computing and Information Systems

In this paper, we summarize the discussions of the panel on "Advances in Data Modeling Research," held at the Americas Conference on Information Systems (AMCIS) in 2005. We focus on four primary areas where data modeling research offers rich opportunities: spatio-temporal semantics, genome research, ontological analysis and empirical evaluation of existing models. We highlight past work in each area and also discuss open questions, with a view to promoting future research in the overall data modeling area.

Systems Analysis & Design: An Essential Part Of Is Education, Albert L. Harris, Michael Lang, Briony J. Oates, Keng Siau

Research Collection School Of Computing and Information Systems

Systems analysis and design has been as critical building block in Information Systems (IS) education since the inception of the IS major. Whether it is taught using the traditional or "structured approach or the object-oriented approach, it exposes students to the different methods, tools, and techniques used in developing new systems, develops students analytical and problem-solving skills, teaches fact-finding and data gathering techniques, and provides teamwork skills. All of these are valuable skills for systems analysts. This paper introduces the reader of this special issue on systems analysis and design education to the issue, discusses the two approaches to teaching …

Negative Impact Of Noise On The Principal Component Analysis Of Nmr Data, Steven M. Halouska, Robert Powers

Department of Chemistry: Faculty Publications

Principal component analysis (PCA) is routinely applied to the study of NMR based metabolomic data. PCA is used to simplify the examination of complex metabolite mixtures obtained from biological samples that may be composed of hundreds or thousands of chemical components. PCA is primarily used to identify relative changes in the concentration of metabolites to identify trends or characteristics within the NMR data that permits discrimination between various samples that differ in their source or treatment. A common concern with PCA of NMR data is the potential over emphasis of small changes in high concentration metabolites that would over-shadow signifi …

Stability Of Warfarin Solutions For Drug–Protein Binding Measurements: Spectroscopic And Chromatographic Studies, Annette C. Moser, Charles A. Kingsbury, David S. Hage

Department of Chemistry: Faculty Publications

Warfarin is commonly used in drug–protein binding studies as a displacement marker for Sudlow site I on the protein human serum albumin (HSA). This study examined the stability of aqueous warfarin solutions prepared for such experiments. This was investigated using NMR spectroscopy and affinity chromatography. It was found by 1H NMR that warfarin underwent a slow first-order conversion in aqueous solution. The rate of this reaction increased with temperature, giving rate constants at pH 7.4 of 0.0086 h⁻¹ at 25 °C and 0.041 h⁻¹ at 37 °C. It was concluded from further 1H and 13C NMR studies, along …

A Minimum-Impact Method For Measuring Corrosion Rate Of Steel-Hulled Shipwrecks In Seawater, Matthew A. Russell, David L. Conlin, Larry E. Murphy, Donald L. Johnson, Brent M. Wilson, James D. Carr

Department of Chemistry: Faculty Publications

Current research on USS Arizona is focused on a minimum-impact technique for calculating corrosion rate of the battleship’s steel hull by analysing physical and chemical properties of marine encrustation covering the exposed hull. An equation is derived that allows concretion thickness, density, and total iron content to be used to calculate corrosion rate of steel hull plate.

Puncturing Ability Of Idealized Canine Teeth: Edged And Non-Edged Shanks, Patricia W. Freeman, Cliff A. Lemen

School of Natural Resources: Faculty Publications

Idealized edged and non-edged indenters, mimicking canine teeth, were used to puncture thin materials and thick materials. Less force was needed for the edged (triangular in cross section) indenter to penetrate thin Mylar, paper, leather, beetle elytra and turkey skin than the non-edged (circular in cross-section) indenter. Oak, grass and magnolia leaves responded equally to both indenters. In thick materials, the edged indenter punctured beetles, shrimp, bananas, and chicken flesh more easily than the non-edged indenter. Apple, tomato and avocado were punctured equally well. The edged indenter directs cracks at the corners so that the material can fold away in …

Analytical Solutions For The Electromagnetic Fields Of Tightly Focused Laser Beams Of Arbitrary Pulse Length, Scott M. Sepke, Donald Umstadter

Donald Umstadter Publications

The analytical solution for a monochromatic focused laser beam was recently published [Opt. Lett. 31, 1447 (2006)]. The effect of introducing bandwidth by including a finite-length temporal pulse envelope is included exactly. This is done formally first in the frequency domain for an arbitrary pulse shape, and the specific case of a cosine-squared envelope is then solved analytically for all pulse lengths, thereby decreasing the computation time by 2 orders of magnitude. The inclusion of longer wavelengths reduces the fraction of laser energy in the focus from 86.5% to 83.5% for a 5 fs Ti:sapphire laser and 72.7% in a …

Exact Analytical Solution For The Vector Electromagnetic Field Of Gaussian, Flattened Gaussian, And Annular Gaussian Laser Modes, Scott M. Sepke, Donald Umstadter

Donald Umstadter Publications

The exact vector integral solution for all the electromagnetic field components of a general flattened Gaussian laser mode is derived by using the angular spectrum method. This solution includes the pure and annular Gaussian modes as special cases. The integrals are of the form of Gegenbauer’s finite integral and are computed analytically for each case, yielding fields satisfying the Maxwell equations exactly in the form of quickly converging Fourier–Gegenbauer series.

Determination Of Diphacinone Residues In Hawaiian Invertebrates, Thomas M. Primus, Dennis J. Kohler, John J. Johnston

United States Department of Agriculture Wildlife Services: Staff Publications

A reversed-phase ion-pair liquid chromatographic analysis combined with a solid-phase extraction clean-up method is used to assess the quantity of diphacinone residue found in invertebrates. Three invertebrate species are exposed to commercially available diphacinone-fortified bait used for rat control. The invertebrate samples are collected, frozen, and shipped to the laboratory. The samples are homogenized after cryogenic freezing. A portion of the homogenized samples are extracted with acidified chloroform–acetone, followed by cleanup with a silica solid-phase extraction column. Diphacinone is detected by UV absorption at 325 nm after separation by the chromatographic system. The method limit of detection (MLOD) for snail …

Developing And Extending Sustainable Agriculture: A New Social Contract, Michele Schoeneberger, Gary Bentrup, Charles A. Francis, Richard Straight

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Conclusions

Based on the practical community applications of woody buffe rs and multifuncti onal areas that grew from the ini tial concepts ofecobelts. we are convinced that this type of initiative is a viable option in establishing a positive interface between different types of human activities. The challenge becomes more real every day, as cities expand and both city-edge subdivisions and acreages create ever more interfaces between people with different and often con!1icting activities and basic values. There is a need to provide some logical and acceptable boundary between these people and their different lifestyles. It is also desirable to …

Grid-Partition Index: A Hybrid Approach To Nearest-Neighbor Queries In Wireless Location-Based Services, Baihua Zheng, Jianliang Xu, Wang-Chien Lee, Dik Lun Lee

Research Collection School Of Computing and Information Systems

Traditional nearest-neighbor (NN) search is based on two basic indexing approaches: object-based indexing and solution-based indexing. The former is constructed based on the locations of data objects: using some distance heuristics on object locations. The latter is built on a precomputed solution space. Thus, NN queries can be reduced to and processed as simple point queries in this solution space. Both approaches exhibit some disadvantages, especially when employed for wireless data broadcast in mobile computing environments. In this paper, we introduce a new index method, called the grid-partition index, to support NN search in both ondemand access and periodic broadcast …

The Impact Of Financial Market And Resale Market On Firm Strategies, Zhiling Guo, Andrew B. Whinston

Research Collection School Of Computing and Information Systems

The ever-increasing use of information technology (IT) in business transactions greatly expands firms? exposure to different electronic markets. This paper provides a framework to understand how firms can leverage different strategies across external financial markets and an internal resale market to improve overall profitability. We develop a model in which a group of risk-averse retailers sell a homogeneous product to their respective uncertain consumer markets. We study a scenario where an internal resale market can be constructed among the retailers and outside financial markets can be used to improve their ability to manage uncertainty. We identify strategies for retailers operating …

Efficient Mining Of Group Patterns From User Movement Data, Yida Wang, Ee Peng Lim, San-Yih Hwang

Research Collection School Of Computing and Information Systems

In this paper, we present a new approach to derive groupings of mobile users based on their movement data. We assume that the user movement data are collected by logging location data emitted from mobile devices tracking users. We formally define group pattern as a group of users that are within a distance threshold from one another for at least a minimum duration. To mine group patterns, we first propose two algorithms, namely AGP and VG-growth. In our first set of experiments, it is shown when both the number of users and logging duration are large, AGP and VG-growth are …

Visualization For Analyzing Trajectory-Based Metaheuristic Search Algorithms, Steven Halim, Roland H. C. Yap, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

No abstract provided.

A Cool Eastern Pacific Ocean At The Close Of The Last Interglacial Complex, Daniel R. Muhs, Kathleen R. Simmons, George L. Kennedy, Kenneth R. Ludwig, Lindsey T. Groves

United States Geological Survey: Staff Publications

New high-precision thermal ionization mass-spectrometric (TIMS) U-series ages of solitary corals (Balanophyllia elegans) from several marine terrace localities along the California and southern Oregon coasts date to the ~80,000 yr BP high stand of sea, correlative with marine isotope substage 5a, late in the last interglacial complex. Ages of multiple corals from localities north of Point Año Nuevo (central California) and San Nicolas Island (southern California) suggest that this high sea stand could have lasted at least 8000 yr, from ~84,000 to ~76,000 yr BP. These ages overlap with those from marine deposits on tectonically stable Bermuda and …

Paleoclimatic Evidence For Future Ice-Sheet Instability And Rapid Sea-Level Rise, Jonathan T. Overpeck, Bette L. Otto-Bliesner, Gifford H. Miller, Daniel R. Muhs, Richard B. Alley, Jeffrey T. Kiehl

United States Geological Survey: Staff Publications

Sea-level rise from melting of polar ice sheets is one of the largest potential threats of future climate change. Polar warming by the year 2100 may reach levels similar to those of 130,000 to 127,000 years ago that were associated with sea levels several meters above modern levels; both the Greenland Ice Sheet and portions of the Antarctic Ice Sheet may be vulnerable. The record of past ice-sheet melting indicates that the rate of future melting and related sea-level rise could be faster than widely thought.

Status Of Feral Pigs In Kansas And Nebraska, Philip S. Gipson, Charles D. Lee, Sam Wilson, James R. Thiele, Deke Hobbick

United States Geological Survey: Staff Publications

Wild pigs have expanded their range markedly during the last 30 years. In Kansas feral pigs from domestic stock were first reported in 1994 on Fort Riley Army Base. During 2005, 2006, and 2007 the occurrence of reproducing wild pigs was confirmed on 18 sites throughout Kansas and 4 sites in Nebraska. One Nebraska population is in a county neighboring Kansas. Estimated numbers of pigs ranged from 8-10 individuals at each of 2 sites in Kansas to more than 30 on each of 3 other sites. The wild pig population in Kansas appears to be changing from 1 predominantly of …

Multi-Species Patterns Of Avian Cholera Mortality In Nebraska’S Rainwater Basin, Julie A. Blanchong, Michael D. Samuel, Gene Mack

United States Geological Survey: Staff Publications

Nebraska’s Rainwater Basin (RWB) is a key spring migration area for millions of waterfowl and other avian species. Avian cholera has been endemic in the RWB since the 1970s and in some years tens of thousands of waterfowl have died from the disease. We evaluated patterns of avian cholera mortality in waterfowl species using the RWB during the last quarter of the 20th century. Mortality patterns changed between the years before (1976–1988) and coincident with (1989–1999) the dramatic increases in lesser snow goose abundance and mortality. Lesser snow geese (Chen caerulescens caerulescens) have commonly been associated with mortality …

A Continuous 250,000 Yr Record Of Oxygen And Carbon Isotopes In Ostracode And Bulk-Sediment Carbonate From Bear Lake, Utah-Idaho, Walter E. Dean, Jordon Bright, Darrell S. Kaufman, Richard M. Forester

United States Geological Survey: Staff Publications

Oxygen and carbon isotopes from a continuous, 120-m-long, carbonate-rich core from Bear Lake, Utah-Idaho, document dramatic fluctuations in the hydrologic budget of the lake over the last 250,000 yr. Isotopic analyses of bulk sediment samples capture millennialscale variability. Ostracode calcite was analyzed from 78 levels, mainly from the upper half of the core where valves are better preserved, to compare the isotopic value of purely endogenic carbonate with the bulk sediment, which comprises both endogenic and detrital components. The long core exhibits three relatively brief intervals with abundant endogenic aragonite (50±10%) and enriched δ¹⁸O and δ¹³C. …

Alpersite (Mg,Cu)So4•7h2O, A New Mineral Of The Melanterite Group, And Cuprian Pentahydrite: Their Occurrence Within Mine Waste, Ronald C. Peterson, Jane M. Hammarstrom, Robert R. Seal Ii

United States Geological Survey: Staff Publications

Alpersite, Mg_0.58 Cu_0.37 Zn_0.02 Mn_0.02 Fe_0.01SO₄ •7H₂ O, a new mineral species with direct relevance to reactions in mine waste, occurs in a mineralogically zoned assemblage in sheltered areas at the abandoned Big Mike mine in central Nevada at a relative humidity of 65% and T = 4 °C. Blue alpersite, which is isostructural with melanterite (FeSO₄ •7H₂ O), is overlain by a light blue to white layer dominated by pickeringite, alunogen, and epsomite. X-ray diffraction data (MoKα radiation) from a single crystal of alpersite were refined in P2_{1 …}

Abundance And Distribution Of Selected Elements In Soils, Stream Sediments, And Selected Forage Plants From Desert Tortoise Habitats In The Mojave And Colorado Deserts, Usa, M. A. Chaffee, K. H. Berry

United States Geological Survey: Staff Publications

A baseline and background chemical survey was conducted in southeastern California, USA, to identify potential sources of toxicants in natural and anthropogenically-altered habitats of the threatened desert tortoise (Gopherus agassizii). Soil, stream sediment, and plant samples were collected from six tortoise habitat study areas in the Mojave and Colorado deserts and analysed for up to 66 different elements. The chemical analyses provided new information on the abundances and distributions of selected elements in this region. Soil, stream-sediment, and plant analyses showed distinct variations in bulk chemistries from locality to locality. Variations were, in general, consistent with the many …

Mineralogical Characterization Of Protolith And Fault Rocks From The Safod Main Hole, John G. Solum, Stephen H. Hickman, David A. Lockner, Diane E. Moore, Ben A. Van Der Pluijm, James P. Evans

United States Geological Survey: Staff Publications

Washed cuttings provide a continuous record of the rocks encountered during drilling of the main hole of the San Andreas Fault Observatory at Depth (SAFOD). Both protolith and fault rocks exhibit a wide variety of mineral assemblages that reflect variations in some combination of lithology, P-T conditions, deformation mechanisms, and fluid composition and abundance. Regions of distinct neomineralization bounded by faults may record alteration associated with fluid reservoirs confined by faults. In addition, both smectites occurring as mixed-layer phases and serpentine minerals are found in association with active strands of the San Andreas Fault that were intersected during drilling, although …

A Method For Mapping Corn Using The Us Geological Survey 1992 National Land Cover Dataset, S. K. Maxwell, J. R. Nuckols, M. H. Ward

United States Geological Survey: Staff Publications

Long-term exposure to elevated nitrate levels in community drinking water supplies has been associated with an elevated risk of several cancers including non-Hodgkin’s lymphoma, colon cancer, and bladder cancer. To estimate human exposure to nitrate, specific crop type information is needed as fertilizer application rates vary widely by crop type. Corn requires the highest application of nitrogen fertilizer of crops grown in the Midwest US.We developed a method to refine the US Geological Survey National Land Cover Dataset (NLCD) (including map and original Landsat images) to distinguish corn from other crops. Overall average agreement between the resulting corn and other …

Seasonal And Spatial Patterns Of Metals At A Restored Copper Mine Site. I. Stream Copper And Zinc, Dustin G. Bambic, Charles N. Alpers, Peter G. Green, Eileen Fanelli, Wendy K. Silk

United States Geological Survey: Staff Publications

Seasonal and spatial variations in metal concentrations and pH were found in a stream at a restored copper mine site located near a massive sulfide deposit in the Foothill copper-zinc belt of the Sierra Nevada, California. At the mouth of the stream, copper concentrations increased and pH decreased with increased streamflow after the onset of winter rain and, unexpectedly, reached extreme values 1 or 2 months after peaks in the seasonal hydrographs. In contrast, aqueous zinc and sulfate concentrations were highest during low-flow periods. Spatial variation was assessed in 400 m of reach encompassing an acidic, metal-laden seep. At this …