Physical Sciences and Mathematics Commons^™

Quantifying The Adaptive Cycle, David G. Angeler, Craig R. Allen, Ahjond S. Garmestani, Lance H. Gunderson, Olle Hjerne, Monika Winder

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term …

Unique Pseudo-Expectations For C∗-Inclusions, David R. Pitts, Vrej Zarikian

Department of Mathematics: Faculty Publications

Given an inclusion D⊆C of unital C ∗ -algebras (with common unit), a unital completely positive linear map Φ of C into the injective envelope I(D) of D which extends the inclusion of D into I(D) is a pseudo-expectation. Pseudo-expectations are generalizations of conditional expectations, but with the advantage that they always exist. The set PsExp(C,D) of all pseudo-expectations is a convex set, and when D is Abelian, we prove a Krein–Milman type theorem showing that PsExp(C,D) can be recovered from its set of extreme points. In general, PsExp(C,D) is not a singleton. However, there are large and natural classes …

U.S. Drought Monitor, December 22, 2015, Richard R. Heim Jr.

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for December 22, 2015 (12/22/15) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.

A Desert In Disguise: The Resilience Of The Nebraska Sandhills, Jeff Hartman

School of Natural Resources: Dissertations, Theses, and Student Research

The Nebraska Sandhills are the largest sand dune system in the Western Hemisphere, and are unique because they remain relatively undisturbed from row crop agriculture. Research in the past two decades demonstrated that the Sandhills are dynamic on millennial timescales, switching between stabilized, vegetated states to non-vegetated, mobilized states. The Sandhills are currently stabilized, but understanding how ecological processes are altered as sand dunes transition from stabilized to mobilized states, provides insight into the thresholds, stability, and resilience of this grassland ecosystem. My research investigated the impacts of vegetation disturbances on ecological processes and the sand dune surface stability. For …

Phosphorus Release Potential Of Agricultural Soils Of The United States, Rebecca A. Young

School of Natural Resources: Dissertations, Theses, and Student Research

Phosphorus (P) is one of the leading causes of surface water quality decline in the United States, leading to algal blooms and hypoxia in lakes and streams. Decreasing conservation funds dictate that agencies such as the Natural Resources Conservation Service, maximizes its effectiveness and efficiency in implementing practices to address P management and runoff on agricultural lands. Additional information on P behavior in soil is needed to improve P management plans to reduce pollution risk at the watershed, farm, and field scales. This research focuses on the development of total soil P release models, to be included into assessment and …

U.S. Drought Monitor, December 15, 2015, Richard Tinker

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for December 15, 2015 (12/15/15) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.

U.S. Vehicle Efficiency Standards, Derek Baylog

Op-Eds from ENSC230 Energy and the Environment: Economics and Policies

The United States is a driving force of the global economy and a major innovator in the technology sector. For decades the world has looked to The United States as a leader of great technological advancements with the strong economy to allow investors a chance make these technologies a reality. So why is it now that we lag behind other countries when it comes to making our technology energy efficient? Sure we’ve been steadily growing our production of renewable resources with wind and solar energy, bet we are still behind in the second largest source of pollution, transportation. According to …

When Addressing Climate Change, Don’T Forget Animal Agriculture, Aaron Matzke

Op-Eds from ENSC230 Energy and the Environment: Economics and Policies

As COP 21 closes in Paris, global animal agriculture is a topic that has eluded the international media. Animal agriculture is responsible for more global greenhouse gas emissions than transportation according to the U.N.’s Food and Agriculture Organization. With global population and prosperity rising, the global meat supply is expected to nearly double by 2050. This increase in production will only be achieved if significant steps are taken to promote sustainability through existing techniques globally, and to regulate air contamination in industrial feedlots in the United States. Alternative meat production methods, which have seen considerable investment recently, could supplement animal …

Energy Subsidies And The Future Of Power, Christian Jewett

Op-Eds from ENSC230 Energy and the Environment: Economics and Policies

The modern political climate has grown rife with talk concerning the use of fossil fuels as an energy source and how this may impact our planet for generations to come. The Left and the Right seem to be at odds over whether or not climate change is actually occurring, or who is causing it. Additionally, the energy industry likes to tout their “low-cost” energy sources as a boon to the global economy as well as a benefit to the consumer at large. However, are coal, oil, and natural gas truly the “cheapest” sources of energy? Whether or not one believes …

Making Walkable Communities, Katie Zuehlke

Op-Eds from ENSC230 Energy and the Environment: Economics and Policies

There is no doubt that global warming is happening. With all the rage about climate change and global warming people should be doing more about it than just reading about it in the news. We should be making efforts towards making changes on a local level. This in turn could grow to a national level with more and more people participating in the movement and actually make global changes, instead of just talking about it. When the scale of participants grows the scale of the changes made will grow as well and this will be the beginning of the changes …

Incentives Critical To Full Wind Power Potential In Nebraska, Michael Neale

Op-Eds from ENSC230 Energy and the Environment: Economics and Policies

On August 3rd, President Obama and the EPA announced the Clean Power Plan (CPP) with the goal of cutting 32% of carbon emissions nationwide by 2030. The plan institutes carbon reduction requirements for all states based on their current sources of energy, for Nebraska the goal is 40%. The next day, Governor Ricketts and his Attorney General announced they would be fighting the mandate in court; stating the plan is unlawful federal government overreach, while expressing concerns the reduction are infeasible in the timeframe given and will drive up electricity costs. Governor Ricketts misses the point on this. Reducing carbon …

Longevity Of Mineral Supplements Within The Soil And Associated Use By White-Tailed Deer, Brian C. Peterson, Keith D. Koupal, Andrew K. Schissel, Cody M. Siegel

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Humans have baited wildlife such as white-tailed deer (Odocoileus virginianus) for generations with the primary purpose of increasing hunting harvest success. Baiting regulation changes are often considered by state management agencies as they pertain to hunting opportunity, fair chase, and disease risk. Cervids require a variety of minerals to supplement biological processes, especially sodium (Na), calcium (Ca), and phosphorus (P). We developed artificial mineral supplement sites set in front of trail cameras to monitor deer use. Pooled soil samples were collected at mineral sites and compared to the surrounding area to determine the longevity of elevated minerals levels …

Three-Dimensional Wind Speed And Flux Measurements Over A Rain-Fed Soybean Field Using Orthogonal And Non-Orthogonal Sonic Anemometer Designs, Taylor Thomas

School of Natural Resources: Dissertations, Theses, and Student Research

The eddy covariance method for estimating fluxes of trace gases, energy and momentum in the constant flux layer above a plant canopy fundamentally relies on accurate measurements of the vertical wind speed. This wind speed is typically measured using a three-dimensional ultrasonic anemometer. Previous studies comparing anemometers with orthogonal transducer sets to those with non-orthogonal transducer sets suggest differences in measured 3D wind speed components, particularly for a vertical component. These differences, attributed to additional flow distortion caused by the non-orthogonal transducer arrangement and support structure, directly affect fluxes of trace gases, energy and momentum. A field experiment was conducted …

Confusing Cafe Standards, Logan Neal

Op-Eds from ENSC230 Energy and the Environment: Economics and Policies

Our homes are one of our most prized possessions, because of the many things it provides. Trying to keep your house from falling apart, can seem like a never ending task. If you neglect these tasks your house can go from a home to a death trap very quickly. While your house is your home, the earth is home to you, your home, along with generation yet to be born. Just like your individual home, the earth requires tasks to be done to keep it from killing us all. Today addressing the problem of greenhouse gases (GHG) emissions needs to …

Geographic Variation, Null Hypotheses, And Subspecies Limits In The California Gnatcatcher: A Response To Mccormack And Maley, Robert M. Zink, Jeffrey G. Groth, Hernan Vázquez-Miranda

School of Natural Resources: Faculty Publications

We interpreted the results of nuclear DNA sequencing to be inconsistent with the recognition of California Gnatcatcher (Polioptila californica) subspecies. McCormack and Maley (2015) suggested that our data did support 2 taxa, one of which was P. c. californica, listed as Threatened under the Endangered Species Act (ESA). We summarize here how 2 sets of researchers with access to the same data reached different conclusions by including different analyses. We included the southern subspecies’ boundary from the taxonomy of Atwood (1991), the taxonomic basis for the ESA listing, which resulted in an Analysis of Molecular Variance that …

Hexagonal Rare-Earth Manganites As Promising Photovoltaics And Light Polarizers, Xin Huang, Tula R. Paudel, Shuai Dong, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Ferroelectric materials possess a spontaneous electric polarization and may be utilized in various technological applications ranging from nonvolatile memories to solar cells and light polarizers. Recently, hexagonal rareearth manganites, h-RMnO₃ (R is a rare-earth ion), have attracted considerable interest due to their intricate multiferroic properties and improper ferroelectricity characterized by a sizable remnant polarization and high Curie temperature. Here we demonstrate that these compounds can serve as very efficient photovoltaic materials and, in addition, possess remarkable optical anisotropy properties. Using first-principles methods based on density functional theory and considering h-TbMnO₃ as a representative …

The Clean Power Plan Needs To Be A Law, Mitchell Frischmeyer

Op-Eds from ENSC230 Energy and the Environment: Economics and Policies

The Clean Power Plan (CPP) is a long overdue policy which is necessary to direct national investment in emerging markets and create an intelligent energy infrastructure that strives to operate at max efficiency. To this point, the US has developed using inefficient and dirty fuels, a method which allowed for cheap and reliable energy generation, but is largely responsible for the change in global climate. If we expect to prevent climate change, our energy infrastructure must be reformed. Countries like Denmark have led the way in energy reform by creating policies set to reach 100% renewable generation by 2050 (8). …

Comparison Theorems And Asymptotic Behavior Of Solutions Of Discrete Fractional Equations, Baoguo Jia, Lynn Erbe, Allan Peterson

Department of Mathematics: Faculty Publications

Consider the following n-th order nabla and delta fractional difference equations

rn r (a)x(t) = c(t)x(t), t 2 Na+1, x(a) > 0.

and

Va+v-1x(t) = c(t)x(t + v - 1), t 2 Na, x(a + n - 1) > 0

We establish comparison theorems by which we compare the solutions x(t) of (*) and (**) with the solutions of the equations rn r(a)x(t) = bx(t) and Dn a+v-1x(t) = bx(t + v -1), respectively, where b is a constant. We obtain four asymptotic results, one of them extends the recent result [F. M. Atici, P. W. Eloe, Rocky Mountain J. Math. 41(2011), …

The Effect Of Manure Application Method On Nutrient And Microbial Runoff Transport And Soil Biological Health Indicators, Nicole R. Schuster

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Two projects were completed to provide significant new information to the agricultural industry regarding the environmental implications and soil health impacts related to land application of swine manure. The first study reports on the runoff transport of nutrients and microbials as affected by manure application method and time following application. The second study provides information about the effect of application method and time following application on soil health indicators using arthropod abundance and diversity as a biological indicator. The information gained through these studies will provide beneficial information to the pork industry on the impact of manure application method and …

Dynamic Data Management In A Data Grid Environment, Björn Barrefors

Department of Computer Science and Engineering: Dissertations, Theses, and Student Research

A data grid is a geographically distributed set of resources providing a facility for computationally intensive analysis of large datasets to a large number of geographically distributed users. In the scientific community, data grids have become increasingly popular as scientific research is driven by large datasets. Until recently, developments in data management for data grids have focused on management of data at lower layers in the data grid architecture. With dataset sizes expected to approach exabyte scale in coming years, data management in data grids are facing a new set of challenges. In particularly, the problem of automatically placing and …

Uses Of Diaryliodonium Salts And Methods For Their Synthesis, Jordan M. Veness

Department of Chemistry: Dissertations, Theses, and Student Research

Diaryliodonium salts have been studied continuously since the first report of their synthesis in 1894. Diaryliodonium salts are I(III) derivatives that are air- and moisturestable. The reactivity of these compounds resembles the organometallic chemistry of heavy transition metal ions such as Pb(IV), Hg(II), Th(III), and Pd(II). A significant advantage of diaryliodonium salts is that they can carry undergo many of the aryl functionalization reactions of heavy metal organometallic complexes, yet they have little to no toxicity and they are relatively inexpensive to prepare. The DiMagno laboratory uses diaryliodonium salts as precursors in the final synthetic step of radiopharmaceuticals; given that …

Wetland Inundation Mapping And Wetland Restoration Planning: A Case Study Of Playa Wetlands, Nebraska, Yue Gu

Community and Regional Planning Program: Theses and Student Projects

There has been a variety of wetland monitoring projects implemented in playa wetlands in Nebraska over the last decades. But there is still a lack of continuous wetland monitoring on long-term and large-area dimension. Because inundation condition is one of the critical parameters to describe wetland hydrologic performance, this study aims to assess the inundation alteration in playa wetlands in Nebraska and evaluate the performance of wetland conservation and restoration practices. This study uses the Landsat data to create playa wetland inundation condition maps and analyze the variation trend of inundated playa wetlands over the past 30 years. The results …

Estimation Of Deep Drainage Differences Between Till And No-Till Irrigated Agriculture, Justin P. Gibson

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Deep drainage was monitored under two center pivot irrigation sites located in south-central Nebraska during the 2013, and part of the 2014, growing seasons. Both fields underwent similar land management except for tillage practice: no-till in one and disk till in the other. Long term deep drainage rates were also estimated from chemical analysis of extracted soil cores, with the aid of the chloride mass balance equation. Mechanisms underpinning differences in deep drainage between the two fields were investigated through the use of unsaturated zone numerical modeling.

Deep drainage estimates from field monitoring indicated that a greater amount of deep …

Rear-Flank Outflow Dynamics And Thermodynamics In The 10 June 2010 Last Chance, Colorado Supercell, Curtis J. Riganti

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

On 10 June 2010, the second Verification of the Origins of Tornadoes Experiment (VORTEX2) armada observed the non-tornadic phase of a supercell thunderstorm near Last Chance, Colorado. Tempest unmanned aircraft system (UAS) data collected in the rear-flank outflow revealed what appeared to be an elevated outflow head, turbulent wake, and a cold secondary outflow surge. Surface thermodynamic and kinematic data collected by StickNets and mobile mesonets suggested that the outflow wake may have extended to or very near the surface, perhaps cutting off the leading edge of the outflow at times. Single-Doppler data collected by the NOAA X-Pol Mobile Polarimetric …

Occupancy Analysis And Density Estimation Of Kori Bustards (Ardeotis Kori) And Helmeted Guineafowl (Numida Meleagris) For Use In Landscape Conservation Planning In The Northern Tuli Game Reserve, Botswana, Kathryn R. Mccollum

School of Natural Resources: Dissertations, Theses, and Student Research

For understudied species, more informed conservation planning and decision-making on both the local and landscape levels may be attained through the use of occupancy and abundance estimations. Here, we focus on two iconic bird species in eastern Botswana, kori bustards (Ardeotis kori) and helmeted guineafowl (Numida meleagris). The overall goal of this project was to better understand the hierarchy of factors that influence occupancy (ψ) and density of kori bustard and helmeted guineafowl populations within the Northern Tuli Game Reserve and how these factors may interact to affect landscape conservation and usage. We performed distance sampling …

Effects Of Wind Turbine Noise On Male Greater Prairie-Chicken Vocalizations And Chorus, Cara E. Whalen

School of Natural Resources: Dissertations, Theses, and Student Research

Wind energy facilities are constructed without full knowledge of their effects on birds, and the noise generated by wind turbines is a particular concern. I investigated the effects of wind turbine noise on male Greater Prairie-Chicken (Tympanuchus cupido pinnatus) vocalizations and chorus near Ainsworth, NE, USA in 2013 and 2014. I studied 14 leks located in the area surrounding a 36-turbine wind energy facility. I used two main approaches in this study. First, I recorded Greater Prairie-Chicken boom, cackle, whine, and whoop vocalizations at each of the study leks and measured the duration, sound pressure level, peak frequency, …

Sequence Stratigraphic Framework Of Carbonate Diagenesis Within Neogene Glaciomarine Sandstones Of The Victoria Land Basin, Antarctica: Insights Into Reservoir Quality In Polar Settings, Daniel P. Dunham

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The controls on reservoir quality of most clastic sedimentary deposits are well-documented and understood. However, comparatively little is known about the reservoir potential of glaciogenic and glaciomarine deposits. This study investigates the Neogene strata of the AND-2A core recovered by the ANDRILL-Southern McMurdo Sound Project in the Victoria Land Basin, Antarctica, as an analog for assessing controls on reservoir quality in glaciomarine deposits. A petrographic analysis was conducted on 60 sandstone samples from various depths throughout the core, and carbonate diagenetic phases and morphologies were documented. Four sequences were examined in detail. Point counting on all samples was done to …

Contact Resistance To Srruo3 And La0.67Sr0.33Mno3 Epitaxial Films, Mohammad Abuwasib, Hyungwoo Lee, Alexei Gruverman, Chang-Beom Eom, Uttam Singisetti

Alexei Gruverman Publications

Contact resistance to the metallic oxide electrodes, SrRuO₃ (SRO) and La_0.67Sr_0.33MnO₃ (LSMO), is an important parameter that affects the ferroelectric tunnel junction (FTJ) device performance. We have systematically studied the contact resistance between metallic oxide electrodes (SRO, LSMO) and contact metal overlayers (Ti, Pt) after exposure to various processing environments. Specific contact resistivity (ρ_c) for Ti and Pt contact metals and the sheet resistance (R_sh) of the metallic oxides are measured after exposure to different reactive ion plasma process steps. Sheet resistance degradation was observed for both SRO and …

Umphlett Qci 2015, Natalie A. Umphlett

HPRCC Personnel Publications

Highlights for the Basin

Temperature and Precipitation Anomalies

Late Hard Freeze

Late Freezes Extended Growing Season

Warm Fall Delays Bird Migrations

Monitoring Water Resources Across the Basin

3-Month Precipitation and Temperature Outlooks

North Shore: A Natural History Of Minnesota’S Superior Coast, Janet R. Keough

The Prairie Naturalist

Many readers of The Prairie Naturalist have lived along or visited Lake Superior’s coast. Like me, you have probably wondered about the geology and history of this beautiful and dramatic feature of northeastern Minnesota. Chel Anderson and Adelheid Fischer have written an accessible book that comprehensively describes the history and geology of the coast, surrounding highlands, and Lake Superior itself. In addition, the authors have provided fascinating subchapters on some of the most interesting species that are key elements of the region.

This rather large but beautiful book is arranged in five major chapters that cover the dominant geological units …