Physical Sciences and Mathematics Commons^™

The Second Annual Space Weather Community Operations Workshop: Advancing Operations Into The Next Decade, Jennifer L. Meehan, Jared Fulgham, W. Kent Tobiska

Graduate Student Publications

No abstract provided.

Workshop Addresses Aviation Community, Jennifer L. Meehan, Joseph Kunches

Graduate Student Publications

No abstract provided.

The Density Factor In The Synthesis Of Carbon Nanotube Forest By Injection Chemical Vapor Deposition, Robert W. Call, C. Read, C Mart, T. C. Shen

Graduate Student Publications

Beneath the seeming straight-forwardness of growing carbon nanotube(CNT) forests by the injection chemical vapor deposition(CVD) method, control of the forest morphology on various substrates is yet to be achieved. Using ferrocene dissolved in xylene as the precursor, we demonstrate that the concentration of ferrocene and the injection rate of the precursor dictate the CNT density of these forests. However, CNT density will also be affected by the substrates and the growth temperature which determine the diffusion of the catalyst adatoms. The CNT growth rate is controlled by the temperature and chemical composition of the gases in the CVD reactor. We …

Approximation Of Range In Materials As A Function Of Incident Electron Energy, Gregory Wilson, Jr Dennison

Graduate Student Publications

A simple composite analytic expression has been developed to approximate the electron range in materials. The expression is applicable over more than six orders of magnitude in energy (<; 10 eV to >; MeV) and range ( 10^-9-10^-2 m), with an uncertainty of ≤ 20% for most conducting, semiconducting, and insulating materials. This is accomplished by fitting data from two standard NIST databases [ESTAR for the higher energy range and the electron inelastic mean free path (IMFP) for the lower energies]. In turn, these data have been fit with well-established semiempirical models for range and IMFP that are related to …

Livestock Foraging Behavior In Response To Sequence And Interactions Among Alkaloids, Tannins, And Saponins, Tiffany L. Jensen

Green Canyon Environmental Research Area, Logan Utah

No abstract provided.

Creating Environmental Leaders Through Service Learning: A Transition From Theory To Real World Application, Roslynn Brain, Robert H. Schmidt

Environment and Society Faculty Publications

No abstract provided.

Changing Lives In A Semester: A Teaching Approach To Help With Tenure And Promotion While Providing An Experience They'll Never Forget, Roslynn Brain

Environment and Society Faculty Publications

Do all university courses have to be structured in a traditional way? For many, the answer is a resounding, NO! Generally, we assume a course needs to have a midterm, final and at least one major project. Although this may fit well with many standard courses, it can be a wonderful experience to deviate away from the norm and delve into the world of service learning.

New Symbolic Tools For Differential Geometry, Gravitation, And Field Theory, Ian M. Anderson, Charles G. Torre

Mathematics and Statistics Faculty Publications

DifferentialGeometry is a Maple software package which symbolically performs fundamental operations of calculus on manifolds, differential geometry, tensor calculus, spinor calculus, Lie algebras, Lie groups, transformation groups, jet spaces, and the variational calculus. These capabilities, combined with dramatic recent improvements in symbolic approaches to solving algebraic and differential equations, have allowed for development of powerful new tools for solving research problems in gravitation and field theory. The purpose of this paper is to describe some of these new tools and present some advanced applications involving: Killing vector fields and isometry groups, Killing tensors, algebraic classification of solutions of the Einstein …

Preservation Of The Seismic Cycle In A Continental Low-Angle Normal Fault: West Salton Detachment Fault, Usa, Mitchell R. Prante, Susanne U. Janecke, James P. Evans

Geosciences Presentations

No abstract provided.

Multiple Deformation Mechanisms Operating At Seismogenic Depths: Tectonic Pseudotachylyte And Associated Deformation From The Central Sierra Nevada, California, Mitchell R. Prante, James P. Evans

Geosciences Presentations

No abstract provided.

Achieving Development Impact Among Pastoral And Agro-Pastoral People: Lessons Learned In Southern Ethiopia, 2000-2009, D. Layne Coppock, Seyoum Tezera, Solomon Desta, Getachew Gebru

Environment and Society Faculty Publications

The outreach and action-research component of the Pastoral Risk Management (PARIMA) project began with a focus on the Borana Plateau of southern Ethiopia in 2000. Our goal was to use participatory methods to learn about development needs and apply the knowledge gained to benefit local communities. Today it is clear that the project has had positive impacts on the lives of thousands of people. This report helps tell this story by emphasizing the process we used.

At the start we knew that the traditional pastoral system was under intense pressure as poverty and hunger were common. Community-based problem diagnosis confirmed …

Botppi, A New Wittig Salt Used In The Synthesis Of 12-(S)-Hydroxy-Eicosatetraenoic Acid [12-(S)-Hete], Michael A. Christiansen, Merritt B. Andrus

Chemistry and Biochemistry Faculty Publications

An efficient route to (Z)-(8-benzyloxy-8-oxooct-3-en-1-yl)triphenylphosphonium iodide, or BOTPPI, is disclosed, complete with full experimental details, NMR spectra, and HRMS data. BOTPPI serves as a surrogate for (Z)-(8-methoxy-8-oxooct-3-en-1-yl)triphenylphosphonium iodide, or MOTPPI, a Wittig salt previously used in two 12-HETE syntheses. BOTPPI has the advantage over MOTPPI of being derived from a sequence for which every intermediate is UV-active and amenable to large-scale chromatographic purification. A formal asymmetric total synthesis of 12-(S)-HETE is also reported, involving a stereoselective phase-transfer catalyzed (PTC) alkylation in its key step.

Windowed Pq-Grams For Approximate Joins Of Data-Centric Xml, Nikolaus Augsten, Michael H. Böhlen, Curtis Dyreson, Johann Gamper

Curtis Dyreson

In data integration applications, a join matches elements that are common to two data sources. Since elements are represented slightly different in each source, an approximate join must be used to do the matching. For XML data, most existing approximate join strategies are based on some ordered tree matching technique, such as the tree edit distance. In data-centric XML, however, the sibling order is irrelevant, and two elements should match even if their subelement order varies. Thus, approximate joins for data-centric XML must leverage unordered tree matching techniques. This is computationally hard since the algorithms cannot rely on a predefined …

Adding Temporal Constraints To Xml Schema, Faiz Currim, Sabah Currim, Curtis Dyreson, Richard T. Snodgrass, Steven W. Thomas, Rui Zhang

Curtis Dyreson

If past versions of XML documents are retained, what of the various integrity constraints defined in XML Schema on those documents? This paper describes how to interpret such constraints as sequenced constraints, applicable at each point in time. We also consider how to add new variants that apply across time, so-called non-sequenced constraints. Our approach supports temporal documents that vary over both valid and transaction time, whose schema can vary over transaction time. We do this by replacing the schema with a (possibly time-varying) temporal schema and replacing the document with a temporal document, both of which are upward compatible …

The Density Factor In The Synthesis Of Carbon Nanotube Forest By Injection Chemical Vapor Deposition, R. W. Call, C. G. Read, C. Mart, T. -C. Shen

T. -C. Shen

Beneath the seeming straight-forwardness of growing carbon nanotube(CNT) forests by the injection chemical vapor deposition(CVD) method, control of the forest morphology on various substrates is yet to be achieved. Using ferrocene dissolved in xylene as the precursor, we demonstrate that the concentration of ferrocene and the injection rate of the precursor dictate the CNT density of these forests. However, CNT density will also be affected by the substrates and the growth temperature which determine the diffusion of the catalyst adatoms. The CNT growth rate is controlled by the temperature and chemical composition of the gases in the CVD reactor. We …

The Role Of Fine-Scale Habitat Associations In Structuring Spider Assemblages: Determinants Of Spatial Patterns In Community Compostion, Stephanie M. Cobbold

Green Canyon Environmental Research Area, Logan Utah

No abstract provided.

Preferred Configurations Of Peptide-Peptide Interactions, U. Adhikari, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The natural and fundamental proclivities of interaction between a pair of peptide units are examined using high-level ab initio calculations. The NH···O H-bonded structure is found to be the most stable configuration of the N-methylacetamide (NMA) model dimer, but only slightly more so than a stacked arrangement. The H-bonded geometry is destabilized by only a small amount if the NH group is lifted out of the plane of the proton-accepting amide. This out-of-plane motion is facilitated by a stabilizing charge transfer from the CO π bond to the NH σ* antibonding orbital. The parallel and antiparallel stacked dimers are nearly …

Sensitivity Of Noncovalent Bonds To Intermolecular Separation: Hydrogen, Halogen, Chalcogen, And Pnicogen Bonds, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

It is well known that noncovalent bonds are weakened when stretched from their equilibrium intermolecular separation. Quantum chemical calculations are used to examine and compare the sensitivity to stretches of hydrogen, halogen, chalcogen, and pnicogen bonds. NH3 was taken as the universal electron donor, paired with HOH and FH in H-bonds, as well as with FPH2, FSH, and FCl. Even though the binding energies span a wide range, stretching the intermolecular separation by 1 Å cuts this quantity by the same proportion, roughly in half, for each system. Taking the sum of van der Waals radii as an arbitrary cutoff, …

Contributions Of Various Noncovalent Bonds To The Interaction Between An Amide And S-Containing Molecules, U. Adhikari, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

N-Methylacetamide, a model of the peptide unit in proteins, is allowed to interact with CH3SH, CH3SCH3, and CH3SSCH3 as models of S-containing amino acid residues. All of the minima are located on the ab initio potential energy surface of each heterodimer. Analysis of the forces holding each complex together identifies a variety of different attractive forces, including SH⋅⋅⋅O, NH⋅⋅⋅S, CH⋅⋅⋅O, CH⋅⋅⋅S, SH⋅⋅⋅π, and CH⋅⋅⋅π H-bonds. Other contributing noncovalent bonds involve charge transfer into σ* and π* antibonds. Whereas some of the H-bonds are strong enough that they represent the sole attractive force in several dimers, albeit not usually in the …

Detailed Comparison Of The Pnicogen Bond With Chalcogen, Halogen And Hydrogen Bonds, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The characteristics of the pnicogen bond are explored using a variety of quantum chemical techniques. In particular, this interaction is compared with its halogen and chalcogen bond cousins, as well as with the more common H-bond. In general, these bonds are all of comparable strength. More specifically, they are strengthened by the presence of an electronegative substituent on the electron-acceptor atom, and each gains strength as one moves down the appropriate column of the periodic table, for example, from N to P to As. These noncovalent bonds owe their stability to a mixture in nearly equal parts of electrostatic attraction …

Effects Of Carbon Chain Substituent On The P∙∙∙N Noncovalent Bond, U. Adhikari, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The effects of carbon chains placed on the electron-accepting P atom of a P⋯N bond are examined via ab initio calculations. Saturated alkyl groups have a mild weakening effect, regardless of chain length. In contrast, incorporation of double bonds into the chain strengthens the interaction, Ctriple bond; length of mdashC triple bonds even more so. These effects are only slightly enhanced by additional conjugated double bonds or an aromatic ring. Placing F atoms onto the carbon chains strengthens the P⋯N bond, but only by a small amount, which wanes as the F atom is displaced further from the P along …

First Steps In Growth Of A Polypeptide Toward Β-Sheet Structure, U. Adhikari, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The full conformational energy surface is examined for a molecule in which a dipeptide is attached to the same spacer group as another peptide chain, so as to model the seminal steps of β-sheet formation. This surface is compared with the geometrical preferences of the isolated dipeptide to extract the perturbations induced by interactions with the second peptide strand. These interpeptide interactions remove any tendency of the dipeptide to form a C5 ring structure, one of its two normally stable geometries. A C7 structure, the preferred conformation of the isolated dipeptide, remains as the global minimum in the full molecule. …

Extrapolation To The Complete Basis Set Limit For Binding Energies Of Noncovalent Interactions, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

A means of extrapolating from double and triple-valence basis sets to a complete basis set is examined in the context of the pnicogen bonds in the BH2P⋯NH3 complexes, with B = CH3, H, NH2, CF3, OH, Cl, F, and NO2. Binding energies converge smoothly, and the trends for the various substituents B are unaffected by the basis set size, extrapolation, or level of inclusion of electron correlation, including MP2 and CCSD(T). The approach appears to be successful also for H-bonded systems, in particular the water dimer. In the event that full extrapolation within the context of CCSD(T) is not feasible, …

Evaluation Of Dft Methods To Study Reactions Of Benzene With Oh Radical, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Several density functional theory” (DFT) methods are applied to two different reaction channels involving OH• + C6H6, and the results compared with high-level ab initio calculations. The OH• adds directly to one C atom in the first channel, first forming an encounter complex with the OH• poised above the aromatic plane. B3LYP, BH&HLYP, and MPW1K compute an accurate estimate of the overall exothermicity, whereas M05-2X, PBE0, and PBEPBE overestimate this quantity to some degree. With the exceptions of PBEPBE and PBE0, the other methods produce an acceptable barrier to addition. All approaches except BH&HLYP correctly predict an exothermic H• abstraction, …

Reuse: Creating A Next Life For Common Items, Roslynn Brain, H. Waldbillig

Environment and Society Faculty Publications

If you are looking for ways to save money and add creative flair to your daily life, reusing everyday items you are likely to throw away could be the answer! We produce an average of 4.4 pounds each of trash a day in the U.S., which amounts to 1,600 pounds per person each year (Environmental Protection Agency, 2011). This yearly waste produced by each one of us is more than the typical weight of a Bison, America’s largest land animal! Often overshadowed by recycling, reusing is a zero-impact technique for waste prevention. By using a product or item in its …

Fostering University-Wide Sustainable Behaviors Through Service Learning: A Classroom Transition From Theory To Real World Application, Roslynn Brain

Environment and Society Faculty Publications

No abstract provided.

Sustainability Cultural Indicators, J. Callewaert, Roslynn Brain, L. C. Malan

Environment and Society Faculty Publications

No abstract provided.

Vermicomposting! Sustain Your Life: Utah State University Extension Sustainability, Roslynn Brain, H. Waldbillig, K. Ladd, J. Greene

Environment and Society Faculty Publications

No abstract provided.

Establishment Of Introduced Reptiles Increases With The Presence And Richness Of Native Congeners, Rodrigo Barbosa Ferreira, Karen H. Beard, Stephen L. Peterson, Sharon A. Poessel, Colin M. Callahan

Wildland Resources Faculty Publications

Darwin proposed two contradictory hypotheses to explain the influence of congeners on the outcomes of invasion: the naturalization hypothesis, which predicts a negative relationship between the presence of congeners and invasion success, and the pre-adaptation hypothesis, which predicts a positive relationship between the presence of congeners and invasion success. Studies testing these hypotheses have shown mixed support. We tested these hypotheses using the establishment success of non-native reptiles and congener presence/absence and richness across the globe. Our results demonstrated support for the pre-adaptation hypothesis. We found that globally, both on islands and continents, establishment success was higher in the presence …

Plant-Soil Feedbacks Provide An Alternative Explanation For Diversity-Productivity Relationships, Andrew Kulmatiski, Karen H. Beard, Justin Heavilin

Wildland Resources Faculty Publications

Plant–soil feedbacks (PSFs) have gained attention for their role in plant community dynamics, but their role in productivity has been overlooked. We developed and tested a biomass-specific, multi-species model to examine the role of PSFs in diversity–productivity relationships. The model predicts a negative relationship between PSFs and overyielding: plants with negative PSFs grow more in communities than in monoculture (i.e. overyield), and plants with positive PSFs grow less in communities than in monoculture (i.e. underyield). This effect is predicted to increase with diversity and saturate at low species richness because the proportion of ‘self-cultivated’ soils rapidly decreases as species are …