Physical Sciences and Mathematics Commons^™

The Dissociation Energy Of The New Diatomic Molecules Sipb And Gepb, A Ciccioli, G Gigli, Giovanni Meloni, E Testani, National Library Of Medicine

Chemistry Faculty Publications

The diatomic molecules SiPb and GePb were for the first time identified by producing high temperature vapors of the constituent pure elements in a "double-oven-like" molecular-effusion assembly. The partial pressures of the atomic, heteronuclear, and homonuclear gaseous species observed in the vapor, namely, Si, Ge, Pb, SiPb, GePb, Pb2, Gen, and Sin (n=2-3), were mass-spectrometrically measured in the overall temperature ranges 1753-1961 K (Ge-Pb) and 1992-2314 K (Si-Pb). The dissociation energies of the new species were determined by second- and third-law analyses of both the direct dissociation reactions and isomolecular exchange reactions involving homonuclear molecules. The selected values of the …

The Visual Image Of Chemistry: Perspectives From The History Of Art And Science, Joachim Schummer, Tami I. Spector

Chemistry Faculty Publications

In this paper we investigate the most important visual stereotypes of chemistry as they occur in current portraits of chemists, depictions of chemical plants, and images of chemical glassware and apparatus. By studying the historical origin and development of these stereotypes within the broader context of the history of art and science, and by applying aesthetic and cultural theories, we explore what these images implicitly communicate about the chemical profession to the public. We conclude that chemists, along with commercial artists, have unknowingly created a visual image of chemistry that frequently conveys negative historical associations, ranging from imposture to kitsch. …

From Morphology To Neural Information: The Electric Sense Of The Skate, Marcelo Camperi, Timothy C. Tricas, Brandon R. Brown

Physics and Astronomy

Morphology typically enhances the fidelity of sensory systems. Sharks, skates, and rays have a well-developed electrosense that presents strikingly unique morphologies. Here, we model the dynamics of the peripheral electrosensory system of the skate, a dorsally flattened batoid, moving near an electric dipole source (e.g., a prey organism). We compute the coincident electric signals that develop across an array of the skate's electrosensors, using electrodynamics married to precise morphological measurements of sensor location, infrastructure, and vector projection. Our results demonstrate that skate morphology enhances electrosensory information. Not only could the skate locate prey using a simple population vector algorithm, but …

Documentation Of Uncertainties And Biases Associated With Surface Temperature Measurement Sites For Climate Change Assessment, Roger A. Pielke Sr., John Nielsen-Gammon, Christopher Davey, Jim Angel, Odie Bliss, Nolan Doesken, Ming Cal, Souleymane Fall, Dev Niyogi, Kevin Gallo, Robert Hale, Kenneth Hubbard, Xiaomao Lin, Hong Li, Sethu Raman

School of Natural Resources: Faculty Publications

Davey and Pielke (2005) presented photographic documentation of poor observation sites within the U.S. Historical Climate Reference Network (USHCN) with respect to monitoring long-term surface air temperature trends. [These photographs were first shown to the community at the 2002 Asheville, North Carolina, meeting of the American Association of State Climatologists (see information online at www. stateclimate.org/meetings/minutes/2002minutes).] Peterson (2006) compared the adjusted climate records of many of these stations and concluded that the similarity between the homogeneity adjusted time series from the good and poorly sited stations supports the view that even stations that do not, upon visual inspection, appear to …

Development Of The Soil Moisture Index To Quantify Agricultural Drought And Its “User Friendliness” In Severity-Area-Duration Assessment, Venkataramana Sridhar, Kenneth Hubbard, Jinshing You, Eric D. Hunt

School of Natural Resources: Faculty Publications

This paper examines the role of soil moisture in quantifying drought through the development of a drought index using observed and modeled soil moisture. In Nebraska, rainfall is received primarily during the crop-growing season and the supply of moisture from the Gulf of Mexico determines if the impending crop year is either normal or anomalous and any deficit of rain leads to a lack of soil moisture storage. Using observed soil moisture from the Automated Weather Data Network (AWDN), the actual available water content for plants is calculated as the difference between observed or modeled soil moisture and wilting point, …

Impacts Of Predators On Northern Bobwhites In The Southeast, John P. Carroll, Susan N. Ellis-Felege, William E. Palmer

School of Natural Resources: Faculty Publications

The northern bobwhite quail (Colinus virginianus) is an important game bird that is intensively managed for hunting recreation in the southeastern United States. Despite interest regionwide, populations have been declining for much of the last 40 years (Brennan 1999). Population declines in the Southeast have occurred as a result of widespread habitat loss associated with land-use changes (Brennan 1999). These land-use changes include both conversion from agricultural to forest landscapes and changes in forest management practices, which result in dense forest canopies that shade required ground vegetation (Brennan 1999, Rollins and Carroll 2001). In addition, low-quality habitats may …

Vegetative And Invertebrate Community Characteristics Of Conservation Reserve Program Fields Relative To Gamebirds In Western Kansas, Elizabeth D. Doxon, John P. Carroll

School of Natural Resources: Faculty Publications

We examined vegetation and invertebrate characteristics, including insect biomass, insect-prey, six Families and seven Orders in four varieties of Conservation Reserve Program (CP10, improved CP10, CP2 and CP25) and wheat fields in western Kansas during Jun. and Jul., 2004 and 2005 relative to gamebird chick ecology. CP10 fields had less bare ground and forbs compared to the other Conservation Practices and CP25 fields had lost much of their original forb component by the end of the study. Although there was little forb component, CP10 fields had high invertebrate biomass. However, CP10 fields demonstrated sizeable declines in the estimated effect size …

Nutrient Cycling In Forage Production Systems, David A. Wedin, Michael P. Russelle

School of Natural Resources: Faculty Publications

In most forage production systems, the nutrients needed for plant growth are provided by microbially mediated breakdown and release of plant-available mineral nutrients from dead plant tissues, livestock excreta, soil organic matter, and geochemically bound mineral forms. Even in fertilized forage systems, determining appropriate fertilizer application rates requires a "systems" approach on the part of the manager (e.g., Di and Cameron, 2000; Rotz et al., 2002). Fertilizer additions are simply one input in the system of inputs, outputs, pools, and fluxes that characterize nutrient cycling in a particular ecosystem.

Analysis Of The Nonlinearity In The Runoff Response To Precipitation Through Numerical Modeling, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

On Diurnal Riparian Zone Groundwater-Level And Streamflow Fluctuations, Jozsef Szilagyi, Zoltan Gribovszki, Peter Kalicz, Mihaly Kucsara

School of Natural Resources: Faculty Publications

No abstract provided.

On The Inherent Asymmetric Nature Of The Complementary Relationship Of Evaporation, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

Estimation Of Catchment-Scale Evapotranspiration From Baseflow Recession Data: Numerical Model And Practical Application Results, Jozsef Szilagyi, Zoltan Gribovszki, Peter Kalicz

School of Natural Resources: Faculty Publications

No abstract provided.

Hungarian National Report On Iahs: 2003-2006, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

On The Inherent Asymmetric Nature Of The Complementary Relationship Of Evaporation, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

An Evaluation Of Modis 250-M Data For Green Lai Estimation In Crops, Anatoly A. Gitelson, Brian D. Wardlow, Galina P. Keydan, Bryan Leavitt

School of Natural Resources: Faculty Publications

Green leaf area index (LAI) is an important variable for climate modeling, estimates of primary production, agricultural yield forecasting, and many other diverse applications. Remotely sensed data provide considerable potential for estimating LAI at local, regional, and global scales. The goal of this study was to retrieve green LAI from MODIS 250-m vegetation index (VI) data for irrigated and rainfed maize and soybeans. The performance of both MODIS-derived NDVI and Wide Dynamic Range Vegetation Index (WDRVI) were evaluated across three growing seasons (2002 through 2004) over a wide range of LAI and also compared to the performance of NDVI and …

Bird Movement Predicts Buggy Creek Virus Infection In Insect Vectors, Charles R. Brown, Mary Bomberger Brown, Amy T. Moore, Nicholas Komar

School of Natural Resources: Faculty Publications

Predicting the spatial foci of zoonotic diseases is a major challenge for epidemiologists and disease ecologists. Migratory birds are often thought to be responsible for introducing some aviozoonotic pathogens such as West Nile and avian influenza viruses to a local area, but most information on how bird movement correlates with virus prevalence is anecdotal or indirect. We report that the prevalence of Buggy Creek virus (BCRV) infection in cimicid swallow bugs (Oeciacus vicarius), the principal invertebrate vector for this virus, was directly associated with the likelihood of movement by cliff swallows (Petrochelidon pyrrhonota), an amplifying host …

Ecological Correlates Of Buggy Creek Virus Infection In Oeciacus Vicarius, Southwestern Nebraska, 2004, Amy T. Moore, Eric A. Edwards, Mary Bomberger Brown, Nicholas Komar, Charles R. Brown

School of Natural Resources: Faculty Publications

Buggy Creek virus (family Togaviridae, genus Alphavirus, BCRV) is an alphavirus within the western equine encephalitis virus complex whose primary vector is the swallow bug, Oeciacus vicarius Horvath (Hemiptera: Cimicidae), an ectoparasite of the colonially nesting cliff swallow, Petrochelidon pyrrhonota, that is also a frequent host for the virus.We investigated ecological correlates of BCRV infection in 100-bug pools at 14 different swallow colony sites in southwestern Nebraska from summer 2004, by using plaque assay on Vero cells to identify cytopathic virus and reverse transcription-polymerase chain reaction to identify noncytopathic viral RNA. We found 26.7% of swallow bug pools …

A Novel Processing Route For The Production Of Nanoparticulate Zinc Oxide Using An Isophthalate Precursor, Grainne Duffy, Declan Mccormack, Suresh Pillai

Articles

Zinc oxide nanoparticles have been processed from a novel isophthalate precursor. In contrast to those processed from an oxalate precursor, this material exhibits three-dimensional, non-directional aggregation behaviour.

Such non-directional aggregation of uniaxial crystallites may allow for the production of structures with a higher proportion of catalytically active surfaces than can be prepared through conventional sol–gel methods. XRD,

FTIR, TEM and SEM were used to characterize the synthesized materials.

Zinc oxide particles synthesized by using isophthalic acid (C6H4-1,3-(COOH)2) are found to be slightly smaller than the previously reported materials prepared through chelation with oxalic acid (H2C2O2・2H2O).

Toward Common Nomenclature And Definitions For Natural Science Professional Collections-Related Positions, Paisley S. Cato, Hugh H. Genoways

University of Nebraska State Museum: Programs Information

Analysis of recent literature and experience with professional positions in several institutions provided the basis for proposing a basic grouping of titles for positions relating to the natural sciences collections profession. Six groups ore proposed with recommendations for education, experience, knowledge, and skills to support the key responsibilities of the positions. Discussions and critiques of these groupings ore anticipated to refine and ultimately result in a standardized nomenclature for natural science collections-related positions.

Mammal Inventories For Eight National Parks In The Southern Colorado Plateau Network, Michael A. Bogan, Keith Geluso, Shauna Haymond, Ernest W. Valdez

United States National Park Service: Publications

Historically, the Colorado Plateau has been the subject of many geological and biological explorations. J. W. Powell explored and mapped the canyon country of the Colorado River in 1869 (Powell 1961). C. H. Merriam, V. Bailey, M. Cary, and other employees of the Bureau of Biological Survey conducted biological explorations of the area in the late 1800s. In recent times, researchers such as S. D. Durrant (1952), Durrant and Robinson (1962), D. M. Armstrong (1972), J. S. Findley et al. (1975), D. F. Hoffmeister (1986), and J. Fitzgerald et al. (1994) have made considerable contributions to our understanding of the …

First Report Of Jefferson's Ground Sloth (Megalonyx Jeffersonii) In North Dakota: Paleobiogeographical And Paleoecological Significance, John W. Hoganson, H. Gregory Mcdonald

United States National Park Service: Publications

A well-preserved ungual of a pes documents the presence of Jefferson’s ground sloth (Megalonyx jeffersonii) at the end of the Wisconsinan in North Dakota. This is the 1st report of M. jeffersonii in North Dakota, and one of few records from the upper Great Plains. An accelerator mass spectrometer radiocarbon age of 11,915 6 40 years ago was obtained from the specimen, suggesting that the sloth resided in North Dakota during the Rancholabrean Land Mammal Age, just before extinction of the species. Palynological records from sites near the sloth occurrence and of the same age indicate that it …

The Relaxed Game Chromatic Index Of K-Degenerate Graphs, Charles Dunn

Faculty Publications

The (r, d)-relaxed coloring game is a two-player game played on the vertex set of a graph G. We consider a natural analogue to this game on the edge set of G called the (r, d)-relaxed edge-coloring game. We consider this game on trees and more generally, on k-degenerate graphs. We show that if G is k-degenerate with ∆(G) = ∆, then the first player, Alice, has a winning strategy for this game with r = ∆+k−1 and d≥2k² + 4k.

Enumerating Building Block Semantics In Genetic Programming, Nicholas Freitag Mcphee, Brian Ohs, Tyler Hutchinson

Faculty Working Papers

This report provides a collection of definitions for the semantics of sub-trees and contexts as manipulated by standard sub-tree crossover in genetic programming (GP). These definitions allow us to completely and compactly describe the exact semantics of the components manipulated by sub-tree crossover, and the semantic results of those interactions. Sub- sequent work shows how these definitions can be used to collect valuable data about the available diversity in a GP population and the opportunities available to sub-tree crossover.

Semantic Building Blocks In Genetic Programming, Nicholas Freitag Mcphee, Brian Ohs, Tyler Hutchinson

Faculty Working Papers

In this paper we present a new mechanism for studying the impact of subtree crossover in terms of semantic building blocks. This approach allows us to completely and compactly describe the semantic action of crossover, and provide insight into what does (or doesn’t) make crossover effective. Our results make it clear that a very high proportion of crossover events (typically over 75% in our experiments) are guaranteed to perform no immediately useful search in the semantic space. Our findings also indicate a strong correlation between lack of progress and high proportions of fixed contexts. These results then suggest several new, …

Sonia Kovalevsky Math For Girls Day General Information, Association For Women In Mathematics, Lincoln University Of Missouri, Donna L. Stallings

Math for Girls Day Documents

PowerPoint presentation about Lincoln University Sonia Kovalevsky (LUSK) Math for Girls Day.

The Challenge Of Understanding Radical Constructivism, Dewey I. Dykstra

Physics Faculty Publications and Presentations

Purpose: This contribution to the Festschrift honoring Ernst von Glasersfeld gives some insight into the perpetual problem of understanding radical constructivism (RC). Parallels with the Middle Way school of Buddhism appear to shed light on this challenge. Conclusions: The hegemony realism has over the thinking of even the most highly educated in our civilization plays a major role in their failure to understand RC. Those still subject to realism in their thinking interpret statements by those in RC in ways incompatible with RC. Until realists disequilibrate over mismatches between realist expectations and experiences, no alternative way of thinking is accessible …

“Once More Into The Breech…”, Dewey I. Dykstra

Physics Faculty Publications and Presentations

No abstract provided.

Breaking The Cycle: Integrating The Mathematics Specialist, T. Hulen

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

Effect Of Field Direction On Electrowetting In A Nanopore, D. Bratko, Christopher D. Daub, Kevin Leung, Alenka Luzar

Chemistry Publications

We manifest a significant influence of field direction and polarity on surface wetting, when the latter is tuned by application of an external electric field. Thermodynamics of field-induced filling of hydrocarbon-like nanopores with water is studied by open ensemble molecular simulation. Increased field strength consistently results in water-filling and electrostriction in hydrophobic nanopores. A threshold field commensurate with surface charge density of about one elementary charge per 10 nm2 suffices to render prototypical paraffin surfaces hydrophilic. When a field is applied in the direction perpendicular to the confining walls, the competition between orientational polarization and angle preferences of interfacial water …

Ground State Structures And Photoelectron Spectroscopy Of [Co-M(Coronene)](-) Complexes, Anil K. Kandalam, Boggavarapu Kiran, Puru Jena, Xiang Li, Andrej Grubisic, Kit H. Bowen

Physics Publications

A synergistic approach involving theory and experiment has been used to study the structure and properties of neutral and negatively charged cobalt-coronene [Com(coronene)] complexes. The calculations are based on density functional theory with generalized gradient approximation for exchange and correlation potential, while the experiments are carried out using photoelectron spectroscopy of mass selected anions. The authors show that the geometries of neutral and anionic Co(coronene) and Co2(coronene) are different from those of the corresponding iron-coronene complexes and that both the Co atom and the dimer prefer to occupy η2-bridge binding sites. However, the magnetic coupling between the Co atoms remains …