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Articles 2161 - 2190 of 24230

Full-Text Articles in Physical Sciences and Mathematics

Tools, Techniques And Teamwork: Transferring New Technologies For Wildlife Management, Conservation And Economic Development, John Eisemann, Gail Keirn Oct 2020

Tools, Techniques And Teamwork: Transferring New Technologies For Wildlife Management, Conservation And Economic Development, John Eisemann, Gail Keirn

United States Department of Agriculture Wildlife Services: Staff Publications

Did you ever wonder who invented radio telemetry? Or breakaway snares? What about the bird repellent methyl anthranilate or the livestock protection collar? These and many other tools used in wildlife damage management resulted from creative thinking by biologists, technicians, researchers and managers working to solve complex wildlife issues. Over the past 90 years, these “aha moments” within the U.S. Department of Agriculture’s Wildlife Services program have ranged from developing novel scare devices, traps and vaccines to exploiting an animal’s visual capabilities to stop unwanted behaviors. Once discovered, these unique ideas may lead to practical, feasible and cost-effective wildlife damage …


Instability Of Glucocorticoid Metabolites In Coyote Scats: Implications For Field Sampling, Erika T. Stevenson, Eric M. Gese, Lorin A. Neuman-Lee, Susannah S. French Oct 2020

Instability Of Glucocorticoid Metabolites In Coyote Scats: Implications For Field Sampling, Erika T. Stevenson, Eric M. Gese, Lorin A. Neuman-Lee, Susannah S. French

United States Department of Agriculture Wildlife Services: Staff Publications

Studying physiologic stress responses can assist in understanding the welfare of animals. One method of measuring the physiologic stress response is evaluating concentrations of glucocorticoid metabolites in feces. Previously, using an adrenocorticotropic hormone challenge, we found fecal glucocorticoid metabolite levels were a reliable indicator of physiologic stress response in coyotes (Canis latrans). We determine whether glucocorticoid metabolite concentrations remain stable when collecting feces over a 2-week period, a timeframe commonly used in scat surveys for wild canids. We collected feces from 6 captive coyotes maintained at the U.S. Department of Agriculture, Wildlife Services, National Wildlife Research Center, Predator …


Calibrating Human Attention As Indicator: Monitoring #Drought In The Twittersphere, Kelly Smith, Andrew Tyre, Zhenghong Tang, Michael Hayes, Adnan Akyuz Oct 2020

Calibrating Human Attention As Indicator: Monitoring #Drought In The Twittersphere, Kelly Smith, Andrew Tyre, Zhenghong Tang, Michael Hayes, Adnan Akyuz

Drought Mitigation Center: Faculty Publications

State climatologists and other expert drought observers have speculated about the value of monitoring Twitter for #drought and related hashtags. This study statistically examines the relationships between the rate of tweeting using #drought and related hashtags, within states, accounting for drought status and news coverage of drought. We collected and geolocated tweets, 2017–18, and used regression analysis and a diversity statistic to explain expected and identify unexpected volumes of tweets. This provides a quantifiable means to detect state-weeks with a volume of tweets that exceeds the upper limit of the prediction interval. To filter out instances where a high volume …


Information Literacy Skills And The Use Of E-Library Resources Among Undergraduates In South-West Nigeria, Paul Adeoye Omosebi, Fehintoluwa E. Omosebi . Oct 2020

Information Literacy Skills And The Use Of E-Library Resources Among Undergraduates In South-West Nigeria, Paul Adeoye Omosebi, Fehintoluwa E. Omosebi .

Library Philosophy and Practice (e-journal)

This study is a correlational survey study which investigates information literacy skills and the use of E-library resources among business administration undergraduates in south-west Nigeria. A sample size of 900 respondents was used but 800 questionnaires were retrieved. The target population for the study comprised of undergraduate business administration students in private universities in Southwest Nigeria. A simple random sampling technique was adopted for the purpose of this study. The questionnaire was the main instrument used for data collection and was divided into three sections namely demographic characteristics, information literacy and use of e-library among students in the private universities …


Cost Effectiveness Of Sample Pooling To Test For Sars-Cov-2, Baha Abdalhamid, Christopher Richard Bilder, Jodi Louise Garrett, Peter Charles Iwen Sep 2020

Cost Effectiveness Of Sample Pooling To Test For Sars-Cov-2, Baha Abdalhamid, Christopher Richard Bilder, Jodi Louise Garrett, Peter Charles Iwen

Department of Statistics: Faculty Publications

No abstract provided.


Indium Segregation To The Selvedge Of In4Se3 (001), Archit Dhingra, Zoe G. Marzouk, Esha Mishra, Pavlo V. Galiy, Taras M. Nenchuk, Peter Dowben Sep 2020

Indium Segregation To The Selvedge Of In4Se3 (001), Archit Dhingra, Zoe G. Marzouk, Esha Mishra, Pavlo V. Galiy, Taras M. Nenchuk, Peter Dowben

Peter Dowben Publications

Thermal motion of the surface atoms will lead to a decrease in photoemission intensity, while surface segregation may result in an increase of some phostoemission intensities. For In4Se3(001), both effects are seen. The Debye–Waller factor plot, based on the temperature dependent X-ray photoemission spectroscopy (XPS) measurements on In4Se3(001), suggests an upper bound of 203 ± 6 K for the effective Debye temperature, based on the surface component of the In 3d5/2 core-level. Indium is found to segregate to selvedge (subsurface region) of the crystal.


Repetitive Sampling And Control Threshold Improve 16s Rrna Gene Sequencing Results From Produced Waters Associated With Hydraulically Fractured Shale, Jenna L. Shelton, Elliott P. Barnhart, Leslie Ruppert, Aaron M. Jubb, Madalyn S. Blondes, Christina A. Devera Sep 2020

Repetitive Sampling And Control Threshold Improve 16s Rrna Gene Sequencing Results From Produced Waters Associated With Hydraulically Fractured Shale, Jenna L. Shelton, Elliott P. Barnhart, Leslie Ruppert, Aaron M. Jubb, Madalyn S. Blondes, Christina A. Devera

United States Geological Survey: Staff Publications

Sequencing microbial DNA from deep subsurface environments is complicated by a number of issues ranging from contamination to non-reproducible results. Many samples obtained from these environments – which are of great interest due to the potential to stimulate microbial methane generation – contain low biomass. Therefore, samples from these environments are difficult to study as sequencing results can be easily impacted by contamination. In this case, the low amount of sample biomass may be effectively swamped by the contaminating DNA and generate misleading results. Additionally, performing field work in these environments can be difficult, as researchers generally have limited access …


Effects Of Riparian Deforestation On Benthic Invertebrate Community And Leaf Processing In Atlantic Forest Streams, Monalisa Silva-Araujo, Eduardo F. Silva-Junior, Vinicius Neres-Lima, Rafael Feijo-Lima, Flavia Tromboni, Christine Lourenco-Amorim, Steven A. Thomas, Timothy P. Moulton Sep 2020

Effects Of Riparian Deforestation On Benthic Invertebrate Community And Leaf Processing In Atlantic Forest Streams, Monalisa Silva-Araujo, Eduardo F. Silva-Junior, Vinicius Neres-Lima, Rafael Feijo-Lima, Flavia Tromboni, Christine Lourenco-Amorim, Steven A. Thomas, Timothy P. Moulton

School of Natural Resources: Faculty Publications

Riparian deforestation may strongly affect stream functioning, with consequences for biodiversity and ecosystem services. These effects can be assessed using bioindicators relating to biotic community structure and ecosystem functioning. We evaluated the effects of riparian deforestation on 1. measures of community structure using aquatic benthic invertebrates, and 2. an aspect of ecosystem functioning, aquatic leaf processing. We selected sites along gradients of riparian land use in four Atlantic rainforest streams and measured physical and chemical properties for their association with riparian deforestation. We sampled benthic invertebrates and calculated metrics of community structure at each site. We measured rates of leaf …


Heat Stored In The Earth System: Where Does The Energy Go?, Karina Von Schuckmann, Lijing Cheng, Matthew D. Palmer, James Hansen, Caterina Tassone, Valentin Aich, Susheel Adusumilli, Hugo Beltrami, Tim Boyer, Francisco José Cuesta-Valero, Damien Desbruyères, Catia Domingues, Almudena García-García, Pierre Gentine, John Gilson, Maximillian Gorfer, Leopold Haimberger, Masayoshi Ishii, Gregory C. Johnson, Rachel Killick, Brian A. King, Gottfried Kirchengast, Nicolas Kolodziejczyk, John Lyman, Ben Marzeion, Michael Mayer, Maeva Monier, Didier Paolo Monselesan, Sarah Purkey, Dean Roemmich, Axel Schweiger, Sonia I. Seneviratne, Andrew Shepherd, Donald A. Slater, Andrea K. Steiner, Fiammetta Straneo, Mary-Louise Timmermans, Susan E. Wijffels Sep 2020

Heat Stored In The Earth System: Where Does The Energy Go?, Karina Von Schuckmann, Lijing Cheng, Matthew D. Palmer, James Hansen, Caterina Tassone, Valentin Aich, Susheel Adusumilli, Hugo Beltrami, Tim Boyer, Francisco José Cuesta-Valero, Damien Desbruyères, Catia Domingues, Almudena García-García, Pierre Gentine, John Gilson, Maximillian Gorfer, Leopold Haimberger, Masayoshi Ishii, Gregory C. Johnson, Rachel Killick, Brian A. King, Gottfried Kirchengast, Nicolas Kolodziejczyk, John Lyman, Ben Marzeion, Michael Mayer, Maeva Monier, Didier Paolo Monselesan, Sarah Purkey, Dean Roemmich, Axel Schweiger, Sonia I. Seneviratne, Andrew Shepherd, Donald A. Slater, Andrea K. Steiner, Fiammetta Straneo, Mary-Louise Timmermans, Susan E. Wijffels

United States Department of Commerce: Staff Publications

Human-induced atmospheric composition changes cause a radiative imbalance at the top of the atmosphere which is driving global warming. This Earth energy imbalance (EEI) is the most critical number defining the prospects for continued global warming and climate change. Understanding the heat gain of the Earth system—and particularly how much and where the heat is distributed—is fundamental to understanding how this affects warming ocean, atmosphere and land; rising surface temperature; sea level; and loss of grounded and floating ice, which are fundamental concerns for society. This study is a Global Climate Observing System (GCOS) concerted international effort to update the …


Dynamic Scaling Of The Generalized Complementary Relationship (Gcr) Improves Long-Term Tendency Estimates In Land Evaporation, Jozsef Szilagyi, Richard Crago, Ning Ma Sep 2020

Dynamic Scaling Of The Generalized Complementary Relationship (Gcr) Improves Long-Term Tendency Estimates In Land Evaporation, Jozsef Szilagyi, Richard Crago, Ning Ma

School of Natural Resources: Faculty Publications

Most large-scale evapotranspiration (ET) estimation methods require detailed information of land use, land cover, and/or soil type on top of various atmospheric measurements. The complementary relationship of evaporation (CR) takes advantage of the inherent dynamic feedback mechanisms found in the soil−vegetation−atmosphere interface for its estimation of ET rates without the need of such biogeophysical data. ET estimates over the conterminous United States by a new, globally calibrated, static scaling (GCR-stat) of the generalized complementary relationship (GCR) of evaporation were compared to similar estimates of an existing, calibration-free version (GCR-dyn) of the GCR that employs a temporally varying dynamic scaling. Simplified …


Agate Fossil Beds National Monument, Paleontological Resources Management Plan (Public Version), Scott Kottkamp, Vincent L. Santucci, Justin S. Tweet, Jessica De Smet, Ellen Stark Sep 2020

Agate Fossil Beds National Monument, Paleontological Resources Management Plan (Public Version), Scott Kottkamp, Vincent L. Santucci, Justin S. Tweet, Jessica De Smet, Ellen Stark

United States National Park Service: Publications

Executive Summary

Since Agate Springs Ranch was founded by James H. Cook in 1887, exquisite examples of transitional Miocene mammalian fauna have been found along this stretch of the Niobrara River valley. Collectively these paleontological discoveries, along with the existing archeological and historical Native American collection, were the basis for establishing Agate Fossil Beds National Monument (AGFO) as a unit of the National Park System (NPS). The fossil remains from the Harrison and Anderson Ranch formations span a short, but important, time period within the Miocene Epoch. AGFO has provided science with an intimate look into North American mammalian evolution …


The Electronic Properties Of The Quasi-One-Dimensional Transition Metal Trichalcogenides: Tis3 And Zrs3, Simeon Gilbert Sep 2020

The Electronic Properties Of The Quasi-One-Dimensional Transition Metal Trichalcogenides: Tis3 And Zrs3, Simeon Gilbert

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

The transition metal trichalcogenides are a class of materials formed by 1D chains of covalently bound MX3 (M=Ti, Zr, Hf, Ta, Nb; X=S, Se, Te) trigonal prisms which are held together by weak van der Waals forces to form 2D sheets. Because of their superior edge termination, these materials suppress edge scattering effects that plague other two-dimensional materials thus enabling devices scaling to widths below 10 nm. Furthermore, this quasi-one-dimensional structure results in highly anisotropic electronic and optical properties which were examined through angle resolved photoemission spectroscopy and scanning photocurrent microscopy. These measurements show that the hole carrier masses …


Research 4.0: Research In The Age Of Automation, Rob Procter, Ben Glover, Elliot Jones Sep 2020

Research 4.0: Research In The Age Of Automation, Rob Procter, Ben Glover, Elliot Jones

Copyright, Fair Use, Scholarly Communication, etc.

Executive Summary

There is a growing consensus that we are at the start of a fourth industrial revolution, driven by developments in Artificial Intelligence, machine learning, robotics, the Internet of Things, 3-D printing, nanotechnology, biotechnology, 5G, new forms of energy storage and quantum computing. This wave of technical innovations is already having a significant impact on how research is conducted, with dramatic change across research methods in recent years within some disciplines, as this project’s interim report set out.

Whilst there are a wide range of technologies associated with the fourth industrial revolution, this report primarily seeks to understand what …


Resilience Characteristics Of The Urban Agriculture System In Lansing, Michigan: Importance Of Support Actors In Local Food Systems, Caitlin K. Kirby, Lissy Goralnik, Jennifer Hodbod, Zach Piso, Julie C. Libarkin Aug 2020

Resilience Characteristics Of The Urban Agriculture System In Lansing, Michigan: Importance Of Support Actors In Local Food Systems, Caitlin K. Kirby, Lissy Goralnik, Jennifer Hodbod, Zach Piso, Julie C. Libarkin

School of Natural Resources: Faculty Publications

Urban agriculture is a growing movement in cities across the United States, including the post-industrial Midwest. Maintaining a resilient local food system is a challenge given the environmental, resource, and institutional barriers facing urban farmers. In this descriptive correlational study, we take an in-depth look at the demographics, farm characteristics, motivations, barriers, and resilience indicators of individuals in the urban agriculture system in Lansing, Michigan, a city of the US Midwest with a growing urban agriculture system. Survey responses (n = 92) revealed that support actors, community gardeners, and farmers have descriptive differences in their motivations, with support actors (e.g. …


Evaluating Airsoft Electric Guns For Control Of Invasive Brown Treesnakes, Adam J. Knox, Björn Lardner, Amy Yackel Adams, Robert N. Reed Aug 2020

Evaluating Airsoft Electric Guns For Control Of Invasive Brown Treesnakes, Adam J. Knox, Björn Lardner, Amy Yackel Adams, Robert N. Reed

United States Geological Survey: Staff Publications

Firearms are often used in lethal control of invasive vertebrates, but safety and regulatory aspects limit the circumstances under which they can be used. During August 2016 at the Brown Treesnake Project laboratory on Guam, we evaluated hobby‐grade Airsoft Electric Guns (AEGs; a lower powered, less‐hazardous, and less‐regulated alternative to firearms) for capture and control of small animals, with specific emphasis on invasive brown treesnakes (Boiga irregularis). Tests of AEGs differing in power with ammunition (plastic pellets) masses ranging from 0.20 to 0.39 g, fired at gelatin blocks from distances of 4, 8, and 12 m, showed that …


Vampire Bats: Preparing For Range Expansion Into The U.S., Michael J. Bodenchuk, David L. Bergman Aug 2020

Vampire Bats: Preparing For Range Expansion Into The U.S., Michael J. Bodenchuk, David L. Bergman

United States Department of Agriculture Wildlife Services: Staff Publications

The common vampire bat apparently is expanding its range northwards in Mexico and seems poised to enter the southern United States. Climate models predict suitable habitat in the U.S. in south Texas and parts of southern Arizona. While vampire bats’ northward range expansion is not unexpected, the fact that this species brings a strain of rabies that impacts livestock and people warrants a strategic response. Annual economic damages from bats are estimated between $7M and $9M, largely associated with deaths of livestock from rabies. To prepare for the emerging rabies issue, USDA Wildlife Services programs in Texas and Arizona have …


The Most-Cited Articles In Data In Brief Journal: A Bibliometric Analysis Using Scopus Data, Lusiana Wulansari, Ansari Saleh Ahmar, Agus Rochmat, Nurmawati, Akbar Iskandar Aug 2020

The Most-Cited Articles In Data In Brief Journal: A Bibliometric Analysis Using Scopus Data, Lusiana Wulansari, Ansari Saleh Ahmar, Agus Rochmat, Nurmawati, Akbar Iskandar

Library Philosophy and Practice (e-journal)

Bibliometric analysis is one of the research approaches that utilizes quantitative and mathematical data to address problems posed in the context of visualization to see patterns in the field of science. In fact, bibliometric analysis may also include a wider overview of the names of the most influential writers in the area of science. This data analysis would discuss the most-cited articles in Data in Brief Journal including the countries, authors. The data was collected on 31st May 2020 of Scopus database. The literature review was conducted using the keyword: ISSN (2352-3409). The bibliometric analysis is visualized utilizing the VosViewer …


Diagrams Of ⋆-Trisections, José Román Aranda, Jesse Moeller Aug 2020

Diagrams Of ⋆-Trisections, José Román Aranda, Jesse Moeller

Department of Mathematics: Faculty Publications

In this note we provide a generalization for the definition of a trisection of a 4-manifold with boundary. We demonstrate the utility of this more general definition by finding a trisection diagram for the Cacime Surface, and also by finding a trisection-theoretic way to perform logarithmic surgery. In addition, we describe how to perform 1-surgery on closed trisections. The insight gained from this description leads us to the classification of an infinite family of genus three trisections. We include an appendix where we extend two classic results for relative trisections for the case when the trisection surface is closed.


Growing Season Air Mass Equivalent Temperature (TE) In The East Central Usa, Dolly Na-Yemeh, Rezaul Mahmood, Gregory Goodrich, Keri Younger, Kevin Cary, Joshua D. Durkee Aug 2020

Growing Season Air Mass Equivalent Temperature (TE) In The East Central Usa, Dolly Na-Yemeh, Rezaul Mahmood, Gregory Goodrich, Keri Younger, Kevin Cary, Joshua D. Durkee

School of Natural Resources: Faculty Publications

Equivalent temperature (TE), which incorporates both dry (surface air temperature, T) and moist heat content associated with atmospheric moisture, is a better indicator of overall atmospheric heat content compared to T alone. This paper investigates the impacts of different types of air masses on TE during the growing season (April–September). The study used data from the Kentucky Mesonet for this purpose. The growing season was divided into early (April–May), mid (June–July), and late (August–September). Analysis suggests that TE for moist tropical (MT) air mass was as high as 61 and 81 °C for the early and …


Routing Optimization In Heterogeneous Wireless Networks For Space And Mission-Driven Internet Of Things (Iot) Environments, Sara El Alaoui Aug 2020

Routing Optimization In Heterogeneous Wireless Networks For Space And Mission-Driven Internet Of Things (Iot) Environments, Sara El Alaoui

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

As technological advances have made it possible to build cheap devices with more processing power and storage, and that are capable of continuously generating large amounts of data, the network has to undergo significant changes as well. The rising number of vendors and variety in platforms and wireless communication technologies have introduced heterogeneity to networks compromising the efficiency of existing routing algorithms. Furthermore, most of the existing solutions assume and require connection to the backbone network and involve changes to the infrastructures, which are not always possible -- a 2018 report by the Federal Communications Commission shows that over 31% …


Development And Performance Assessment Of An Integrated Vermifiltration Based Treatment System For The Treatment Of Feedlot Runoff, Rajneesh Singh, Matteo D'Alessio, Yulie Meneses, Shannon L. Bartelt-Hunt, Brian Woodbury, Chittaranjan Ray Aug 2020

Development And Performance Assessment Of An Integrated Vermifiltration Based Treatment System For The Treatment Of Feedlot Runoff, Rajneesh Singh, Matteo D'Alessio, Yulie Meneses, Shannon L. Bartelt-Hunt, Brian Woodbury, Chittaranjan Ray

Nebraska Water Center: Faculty Publications

The objective of this study was to treat feedlot runoff by developing an ecologically sustainable, affordable, and resilient treatment system having a relatively long life span. Three horizontal flow soil biofilters were utilized in this study: 1) without earthworms and plants (Biofilter (BF)), 2) with earthworms only (Vermifilter (VF)), and 3) with earthworms and plants (Macrophyte Assisted Vermifilter (MAVF)). The experiments were conducted with a hydraulic retention time of four days using Lumbricus terestrris earthworms and Carex frankii wetland plants. The average COD removal from the BF, VF, and MAVF were 23.2–30.4%, 61.4–69.1%, and 68.3–78.1%, respectively. Average TN removal efficiencies …


Nonlocal Complex Potential Theory Of Dissociative Electron Attachment: Inclusion Of Two Vibrational Modes, H. B. Ambalampitiya, Ilya I. Fabrikant Aug 2020

Nonlocal Complex Potential Theory Of Dissociative Electron Attachment: Inclusion Of Two Vibrational Modes, H. B. Ambalampitiya, Ilya I. Fabrikant

Department of Physics and Astronomy: Faculty Publications

The process of dissociative electron attachment (DEA) to molecules with several vibrational degrees of freedom is usually treated in the approximation of the local potential for the description of the nuclear motion. We develop the nonlocal complex potential theory to treat the dissociation dynamics when there is more than one vibrational mode in the neutral molecule. We demonstrate the application of the multimode nonlocal theory to a generic molecule of the type CY3X, where Y denotes the H or F atom and X denotes the halogen atom, with the inclusion of symmetric C–X stretch and CY3 deform …


Using Climate To Explain And Predict West Nile Virus Risk In Nebraska, Kelly Helm Smith, Andrew J. Tyre, Jeff Hamik, Michael J. Hayes, Yuzhen Zhou, Li Dai Aug 2020

Using Climate To Explain And Predict West Nile Virus Risk In Nebraska, Kelly Helm Smith, Andrew J. Tyre, Jeff Hamik, Michael J. Hayes, Yuzhen Zhou, Li Dai

Drought Mitigation Center: Faculty Publications

We used monthly precipitation and temperature data to give early warning of years with higher West Nile Virus (WNV) risk in Nebraska. We used generalized additive models with a negative binomial distribution and smoothing curves to identify combinations of extremes and timing that had the most influence, experimenting with all combinations of temperature and drought data, lagged by 12, 18, 24, 30, and 36 months. We fit models on data from 2002 through 2011, used Akaike's Information Criterion (AIC) to select the best‐fitting model, and used 2012 as out‐of‐sample data for prediction, and repeated this process for each successive year, …


Use Of Citizen Science In Monitoring Groundwater Quality: A Case Study From Nebraska, Christopher Olson Aug 2020

Use Of Citizen Science In Monitoring Groundwater Quality: A Case Study From Nebraska, Christopher Olson

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

Citizen science has a key role in modernizing effective communication between professional scientists and the general public. However, citizen science differs to that of professional science due to equipment and experience and is a topic argued against citizen science. However, technology in water quality testing has developed in simplicity and affordability to a point where high school students, with hands-on training, can collect groundwater samples and test for quality themselves. Nebraska groundwater quality is a critical part of the state and can utilize high school students as citizen scientists for their communities. High school students from rural communities across Nebraska …


Brillouin Zone Center Phonon Modes In Znga2O4, Megan Stokey, Rafal Korlacki, Sean Knight, Matthew J. Hilfiker, Zbigniew Galazka, Klaus Irmscher, Vanya Darakchieva, Mathias Schubert Aug 2020

Brillouin Zone Center Phonon Modes In Znga2O4, Megan Stokey, Rafal Korlacki, Sean Knight, Matthew J. Hilfiker, Zbigniew Galazka, Klaus Irmscher, Vanya Darakchieva, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

Infrared-active lattice mode properties of melt-grown high-quality single bulk crystals of ZnGa2O4 are investigated by combined spectroscopic ellipsometry and density functional theory computation analysis. The normal spinel structure crystals are measured by spectroscopic ellipsometry at room temperature in the range of 100 cm–1–1200 cm–1. The complex-valued dielectric function is determined from a wavenumber-by-wavenumber approach, which is then analyzed by the four-parameter semi-quantum model dielectric function approach augmented by impurity mode contributions. We determine four infrared-active transverse and longitudinal optical mode pairs, five localized impurity mode pairs, and the high frequency dielectric constant. All …


Connections Between The Hydrological Cycle And Crop Yield In The Rainfed U.S. Corn Belt, Wang Zhou, Kaiyu Guan, Bin Peng, Jiancheng Shi, Chongya Jiang, Brian Wardlow, Ming Pan, John S. Kimball, Trenton Franz, Pierre Gentine, Mingzhu He, Jingwen Zhang Aug 2020

Connections Between The Hydrological Cycle And Crop Yield In The Rainfed U.S. Corn Belt, Wang Zhou, Kaiyu Guan, Bin Peng, Jiancheng Shi, Chongya Jiang, Brian Wardlow, Ming Pan, John S. Kimball, Trenton Franz, Pierre Gentine, Mingzhu He, Jingwen Zhang

School of Natural Resources: Faculty Publications

No abstract provided.


Trisections Of Flat Surface Bundles Over Surfaces, Marla Williams Aug 2020

Trisections Of Flat Surface Bundles Over Surfaces, Marla Williams

Department of Mathematics: Dissertations, Theses, and Student Research

A trisection of a smooth 4-manifold is a decomposition into three simple pieces with nice intersection properties. Work by Gay and Kirby shows that every smooth, connected, orientable 4-manifold can be trisected. Natural problems in trisection theory are to exhibit trisections of certain classes of 4-manifolds and to determine the minimal trisection genus of a particular 4-manifold.

Let $\Sigma_g$ denote the closed, connected, orientable surface of genus $g$. In this thesis, we show that the direct product $\Sigma_g\times\Sigma_h$ has a $((2g+1)(2h+1)+1;2g+2h)$-trisection, and that these parameters are minimal. We provide a description of the trisection, and an algorithm to generate a …


Free Charge Carrier Properties In Two-Dimensional Materials And Monoclinic Oxides Studied By Optical Hall Effect, Sean Knight Aug 2020

Free Charge Carrier Properties In Two-Dimensional Materials And Monoclinic Oxides Studied By Optical Hall Effect, Sean Knight

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

In this dissertation, optical Hall effect (OHE) measurements are used to determine the free charge carrier properties of important two-dimensional materials and monoclinic oxides. Two-dimensional material systems have proven useful in high-frequency electronic devices due to their unique properties, such as high mobility, which arise from their two-dimensional nature. Monoclinic oxides exhibit many desirable characteristics, for example low-crystal symmetry which could lead to anisotropic carrier properties. Here, single-crystal monoclinic gallium oxide, an AlInN/GaN-based high-electron-mobility transistor (HEMT) structure, and epitaxial graphene are studied as examples. To characterize these material systems, the OHE measurement technique is employed. The OHE is a physical …


Differences In Soil Water Changes And Canopy Temperature Under Varying Water × Nitrogen Sufficiency For Maize, Tsz Him Lo, Daran Rudnick, Kendall C. Dejonge, Geng Bai, Hope Njuki Nakabuye, Abia Katimbo, Yufeng Ge, Trenton E. Franz, Xin Qiao, Derek M. Heeren Aug 2020

Differences In Soil Water Changes And Canopy Temperature Under Varying Water × Nitrogen Sufficiency For Maize, Tsz Him Lo, Daran Rudnick, Kendall C. Dejonge, Geng Bai, Hope Njuki Nakabuye, Abia Katimbo, Yufeng Ge, Trenton E. Franz, Xin Qiao, Derek M. Heeren

West Central Research and Extension Center, North Platte

Crop nitrogen (N) status is known to affect crop water status and crop water use. To investigate further the N effects on soil water changes and on canopy temperature, three water levels × four N levels were imposed on two growing seasons of maize in west central Nebraska, USA. Soil water changes were measured using a neutron probe, whereas canopy temperature was measured using infrared thermometers on a ground-based mobile platform. At all water levels, soil water losses over monthlong intervals were generally greater as N levels increased. Given equal water levels, early afternoon canopy temperatures were usually lower with …


Nitrate Dynamics And Source Within Nested Watersheds Of An Agricultural Stream, Nebraska, Usa, Galen Richards Aug 2020

Nitrate Dynamics And Source Within Nested Watersheds Of An Agricultural Stream, Nebraska, Usa, Galen Richards

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

Nitrate concentrations have been increasing throughout the globe, primarily due to heightened agricultural activity. Nitrate concentrations in Bazile Creek, located in Northeastern Nebraska, have been steadily rising since the early 2000s. Groundwater nitrate concentrations within the Bazile Creek watershed are high (> 10 mg/L nitrate-N), and there is strong connectivity between groundwater and surface water systems. This study aimed to better understand temporal nitrate concentration variability within the watershed through sampling tributaries and the main channel during baseflow conditions. Nitrate source was also investigated though the use of dual δ15N and δ18O nitrate isotopes, with samples …