Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

PDF

Iowa State University

Selected Works

Discipline
Keyword
Publication Year
Publication

Articles 1 - 30 of 1854

Full-Text Articles in Entire DC Network

Towards Mapping Soil Carbon Landscapes: Issues Of Sampling Scale And Transferability, Bradley A. Miller, Sylvia Koszinski, Wilfried Hierold, Helmut Rogasik, Boris Schröder, Kristof Van Oost, Marc Wehrhan, Michael Sommer Mar 2016

Towards Mapping Soil Carbon Landscapes: Issues Of Sampling Scale And Transferability, Bradley A. Miller, Sylvia Koszinski, Wilfried Hierold, Helmut Rogasik, Boris Schröder, Kristof Van Oost, Marc Wehrhan, Michael Sommer

Bradley A Miller

The conversion of point observations to a geographic field is a necessary step in soil mapping. For pursuing goals of mapping soil carbon at the landscape scale, the relationships between sampling scale, representation of spatial variation, and accuracy of estimated error need to be considered. This study examines the spatial patterns and accuracy of predictions made by different spatial modelling methods on sample sets taken at two different scales. These spatial models are then tested on independent validation sets taken at three different scales. Each spatial modelling method produced similar, but unique, maps of soil organic carbon content (SOC%). Kriging …

Go to article

Use Of Soil Maps And Surveys To Interpret Soil-Landform Assemblages And Soil-Landscape Evolution, Bradley A. Miller, Randall J. Schaetzl Jan 2016

Use Of Soil Maps And Surveys To Interpret Soil-Landform Assemblages And Soil-Landscape Evolution, Bradley A. Miller, Randall J. Schaetzl

Bradley A Miller

Soils form in unconsolidated parent materials, which make them a key link to the geologic system that originally deposited the parent material. In young soils, i.e., those that post-date the last glaciation, parent materials can often be easily identified as to type and depositional system. In a GIS, soil map units can then be geospatially tied to parent materials, enabling the user to create maps of surficial geology. We suggest that maps of this kind have a wide variety of applications in the Earth Sciences, and to that end, provide five examples from temperate climate soil-landscapes.

Go to article

Projected Nesterov’S Proximal-Gradient Signal Recovery From Compressive Poisson Measurements, Renliang Gu, Aleksandar Dogandžić Nov 2015

Projected Nesterov’S Proximal-Gradient Signal Recovery From Compressive Poisson Measurements, Renliang Gu, Aleksandar Dogandžić

Aleksandar Dogandžić

We develop a projected Nesterov’s proximal-gradient (PNPG) scheme for reconstructing sparse signals from compressive Poisson-distributed measurements with the mean signal intensity that follows an affine model with known intercept. The objective function to be minimized is a sum of convex data fidelity (negative log-likelihood (NLL)) and regularization terms. We apply sparse signal regularization where the signal belongs to a nonempty closed convex set within the domain of the NLL and signal sparsity is imposed using total-variation (TV) penalty. We present analytical upper bounds on the regularization tuning constant. The proposed PNPG method employs projected Nesterov’s acceleration step, function restart, and …

Go to article

Perceptions Of Bibliotherapy: A Survey Of Undergraduate Students, Randie D. Camp M.S., Anne Foegen Ph.D., Linda Lind Ph.D., Amy Popillion Ph.D. Oct 2015

Perceptions Of Bibliotherapy: A Survey Of Undergraduate Students, Randie D. Camp M.S., Anne Foegen Ph.D., Linda Lind Ph.D., Amy Popillion Ph.D.

Randie D. Camp, M.S.

Bibliotherapy is one instructional tool teachers can use to help children and adolescents cope with their diverse needs and life’s challenges. In the context of K-12 settings, bibliotherapy is a systematic process utilizing books to transform traditional reading into an instructional strategy to assist educators in meeting the needs of all students. The study presents perceptions of bibliotherapy held by 161 preservice teachers (PSTs) and 87 non-preservice teachers (non-PSTs) and offers insight exploring 5 research questions. Data were collected using a survey which contained demographic items, rating scales, and open-ended items to gather both quantitative and narrative data. Independent samples …

Go to article

Century-Scale Patterns And Trends Of Global Pyrogenic Carbon Emissions And Fire Influences On Terrestrial Carbon Balance, Jia Yang, Hanqin Tian, Bo Tao, Wei Ren, Chaoqun (Crystal) Lu, Shufen Pan, Yuhang Wang, Yongqiang Liu Sep 2015

Century-Scale Patterns And Trends Of Global Pyrogenic Carbon Emissions And Fire Influences On Terrestrial Carbon Balance, Jia Yang, Hanqin Tian, Bo Tao, Wei Ren, Chaoqun (Crystal) Lu, Shufen Pan, Yuhang Wang, Yongqiang Liu

Chaoqun (Crystal) Lu

Fires have consumed a large amount of terrestrial organic carbon and significantly influenced terrestrial ecosystems and the physical climate system over the past century. Although biomass burning has been widely investigated at a global level in recent decades via satellite observations, less work has been conducted to examine the century-scale changes in global fire regimes and fire influences on the terrestrial carbon balance. In this study, we investigated global pyrogenic carbon emissions and fire influences on the terrestrial carbon fluxes from 1901 to 2010 by using a process-based land ecosystem model. Our results show a significant declining trend in global …

Go to article

Mating For Male-Derived Prostaglandin: A Functional Explanation For The Increased Fecundity Of Mated Female Crickets?, Amy M. Worthington, Russell A. Jurenka, Clint D. Kelly Sep 2015

Mating For Male-Derived Prostaglandin: A Functional Explanation For The Increased Fecundity Of Mated Female Crickets?, Amy M. Worthington, Russell A. Jurenka, Clint D. Kelly

Russell A. Jurenka

Direct benefits are considered to be the driving force of high female mating rates, yet species in which females do not receive material resources from males still experience increased fitness from mating frequently. One hypothesis suggests that substances within the ejaculate may boost survival or offspring production. If these materials are limiting to females, they will require continual renewal via mating and could provide a functional understanding of how high mating rates lead to increased female fitness. Using the Texas field cricket, Gryllus texensis, we investigated the sexual transfer of prostaglandin E2, an important mediator of invertebrate reproduction. We determined …

Go to article

Disentangling Climatic And Anthropogenic Controls On Global Terrestrial Evapotranspiration Trends, Jiafu Mao, Wenting Fu, Xiaoying Shi, Daniel M. Ricciuto, Joshua B. Fisher, Robert E. Dickinson, Yaxing Wei, Willis Shem, Shilong Piao, Kaicun Wang, Christopher R. Schwalm, Hanqin Tian, Mingquan Mu, Altaf Arain, Philippe Ciais, Robert Cook, Yongdiu Dai, Daniel Hayes, Forrest M. Hoffman, Maoyi Huang, Suo Huang, Deborah N. Huntzinger, Akihiko Ito, Atul Jain, Anthony W. King, Huimin Lei, Chaoqun (Crystal) Lu, Huimin Lei, Anna M. Michalak, Changhui Peng, Shushi Peng, Benjamin Poulter, Kevin Schaefer, Elshin Jafarov, Peter E. Thornton, Weile Wang, Ning Zeng, Zhenzhong Zeng, Fang Zhao, Qiuan Zhu, Zaichun Zhu Sep 2015

Disentangling Climatic And Anthropogenic Controls On Global Terrestrial Evapotranspiration Trends, Jiafu Mao, Wenting Fu, Xiaoying Shi, Daniel M. Ricciuto, Joshua B. Fisher, Robert E. Dickinson, Yaxing Wei, Willis Shem, Shilong Piao, Kaicun Wang, Christopher R. Schwalm, Hanqin Tian, Mingquan Mu, Altaf Arain, Philippe Ciais, Robert Cook, Yongdiu Dai, Daniel Hayes, Forrest M. Hoffman, Maoyi Huang, Suo Huang, Deborah N. Huntzinger, Akihiko Ito, Atul Jain, Anthony W. King, Huimin Lei, Chaoqun (Crystal) Lu, Huimin Lei, Anna M. Michalak, Changhui Peng, Shushi Peng, Benjamin Poulter, Kevin Schaefer, Elshin Jafarov, Peter E. Thornton, Weile Wang, Ning Zeng, Zhenzhong Zeng, Fang Zhao, Qiuan Zhu, Zaichun Zhu

Chaoqun (Crystal) Lu

We examined natural and anthropogenic controls on terrestrial evapotranspiration (ET) changes from 1982 to 2010 using multiple estimates from remote sensing-based datasets and process-oriented land surface models.A significant increasing trend of ET in each hemisphere was consistently revealed by observationally-constrained data and multi-model ensembles that considered historic natural and anthropogenic drivers. The climate impacts were simulated to determine the spatiotemporal variations in ET. Globally, risingCO2 ranked second in these models after the predominant climatic influences, and yielded decreasing trends in canopy transpiration and ET, especially for tropical forests and high-latitude shrub land. Increasing nitrogen deposition slightly amplified global ET via …

Go to article

Climate Extremes Dominating Seasonal And Interannual Variations In Carbon Export From The Mississippi River Basin, Hanqin Tian, Wei Ren, Jia Yang, Bo Tao, Wei-Jun Cai, Steve E. Lohrenz, Charles S. Hopkinson, Mingliang Liu, Qichun Yang, Chaoqun (Crystal) Lu, Bowen Zhang, Kamaljit Banger, Shufen Pan, Ruoying He, Zuo Xue Sep 2015

Climate Extremes Dominating Seasonal And Interannual Variations In Carbon Export From The Mississippi River Basin, Hanqin Tian, Wei Ren, Jia Yang, Bo Tao, Wei-Jun Cai, Steve E. Lohrenz, Charles S. Hopkinson, Mingliang Liu, Qichun Yang, Chaoqun (Crystal) Lu, Bowen Zhang, Kamaljit Banger, Shufen Pan, Ruoying He, Zuo Xue

Chaoqun (Crystal) Lu

Knowledge about the annual and seasonal patterns of organic and inorganic carbon (C) exports from the major rivers of the world to the coastal ocean is essential for our understanding and potential management of the global C budget so as to limit anthropogenic modification of global climate. Unfortunately our predictive understanding of what controls the timing, magnitude, and quality of C export is still rudimentary. Here we use a process-based coupled hydrologic/ecosystem biogeochemistry model (the Dynamic Land Ecosystem Model) to examine how climate variability and extreme events, changing land use, and atmospheric chemistry have affected the annual and seasonal patterns …

Go to article

Environmental Forcing Does Not Induce Diel Or Synoptic Variation In The Carbon Isotope Content Of Forest Soil Respiration, Steven J. Hall, D. R. Bowling, J. E. Egan Aug 2015

Environmental Forcing Does Not Induce Diel Or Synoptic Variation In The Carbon Isotope Content Of Forest Soil Respiration, Steven J. Hall, D. R. Bowling, J. E. Egan

Steven J. Hall

Recent studies have examined temporal fluctuations in the amount and carbon isotope content (δ13C) of CO2 produced by the respiration of roots and soil organisms. These changes have been correlated with diel cycles of environmental forcing (e.g., sunlight and soil temperature) and with synoptic-scale atmospheric motion (e.g., rain events and pressure-induced ventilation). We used an extensive suite of measurements to examine soil respiration over 2 months in a subalpine forest in Colorado, USA (the Niwot Ridge AmeriFlux forest). Observations included automated measurements of CO2 and δ13C of CO2 in the soil efflux, the soil gas profile, and forest air. There …

Go to article

Improved Detection By Ensemble-Decision Aliquot Ranking Of Circulating Tumor Cells With Low Numbers Of A Targeted Surface Antigen, Eleanor S. Johnson, Robbyn K. Anand, Daniel T. Chiu Aug 2015

Improved Detection By Ensemble-Decision Aliquot Ranking Of Circulating Tumor Cells With Low Numbers Of A Targeted Surface Antigen, Eleanor S. Johnson, Robbyn K. Anand, Daniel T. Chiu

Robbyn Anand

Circulating tumor cells (CTCs) are shed from a solid tumor into the bloodstream and can seed new metastases. CTCs hold promise for cancer diagnosis and prognosis and to increase our understanding of the metastatic process. However, their low numbers in blood and varied phenotypic characteristics make their detection and isolation difficult. One source of heterogeneity among CTCs is molecular: When they leave the primary tumor, these cells must undergo a molecular transition, which increases their mobility and chance of survival in the blood. During this molecular transition, the cells lose some of their epithelial character, which is manifested by the …

Go to article

Lignin Decomposition Is Sustained Under Fluctuating Redox Conditions In Humid Tropical Forest Soils, Steven J. Hall, Whendee L. Silver, Vitaliy I. Timokhin, Kenneth E. Hammel Jul 2015

Lignin Decomposition Is Sustained Under Fluctuating Redox Conditions In Humid Tropical Forest Soils, Steven J. Hall, Whendee L. Silver, Vitaliy I. Timokhin, Kenneth E. Hammel

Steven J. Hall

Lignin mineralization represents a critical flux in the terrestrial carbon (C) cycle, yet little is known about mechanisms and environmental factors controlling lignin breakdown in mineral soils. Hypoxia is thought to suppress lignin decomposition, yet potential effects of oxygen (O2) variability in surface soils have not been explored. Here, we tested the impact of redox fluctuations on lignin breakdown in humid tropical forest soils during ten-week laboratory incubations. We used synthetic lignins labeled with 13C in either of two positions (aromatic methoxyl or propyl side chain Cb) to provide highly sensitive and specific measures of lignin mineralization seldom employed in …

Go to article

Hemocyte Differentiation Mediates The Mosquito Late-Phase Immune Response Against Plasmodium In Anopheles Gambiae, Ryan C. Smith, Carolina Barillas-Mury, Marcelo Jacobs-Lorena Jun 2015

Hemocyte Differentiation Mediates The Mosquito Late-Phase Immune Response Against Plasmodium In Anopheles Gambiae, Ryan C. Smith, Carolina Barillas-Mury, Marcelo Jacobs-Lorena

Ryan C. Smith

Plasmodium parasites must complete development in the mosquito vector for transmission to occur. The mosquito innate immune response is remarkably efficient in limiting parasite numbers. Previous work has identified a LPS-induced TNFα transcription factor (LITAF)-like transcription factor, LITAF-like 3 (LL3), which significantly influences parasite numbers. Here, we demonstrate that LL3 does not influence invasion of the mosquito midgut epithelium or ookinete-to-oocyst differentiation but mediates a late-phase immune response that decreases oocyst survival. LL3 expression in the midgut and hemocytes is activated by ookinete midgut invasion and is independent of the mosquito microbiota, suggesting that LL3 may be a component of …

Go to article

Toward “Optimal” Integration Of Terrestrial Biosphere Models, Christopher R. Schwalm, Deborah N. Huntzinger, Joshua B. Fisher, Anna M. Michalak, Kevin Bowman, Philippe Ciais, Robert Cook, Bassil El-Masri, Daniel Hayes, Maoyi Huang, Akihiko Ito, Atul Jain, Anthony W. King, Hiumin Lei, Junjie Liu, Chaoqun (Crystal) Lu, Jaifu Mao, Shushi Peng, Benjamin Poulter, Daniel Ricciuto, Kevin Schaefer, Xiaoying Shi, Bo Tao, Hanqin Tian, Weile Wang, Yaxing Wei, Jia Yang, Ning Zeng Jun 2015

Toward “Optimal” Integration Of Terrestrial Biosphere Models, Christopher R. Schwalm, Deborah N. Huntzinger, Joshua B. Fisher, Anna M. Michalak, Kevin Bowman, Philippe Ciais, Robert Cook, Bassil El-Masri, Daniel Hayes, Maoyi Huang, Akihiko Ito, Atul Jain, Anthony W. King, Hiumin Lei, Junjie Liu, Chaoqun (Crystal) Lu, Jaifu Mao, Shushi Peng, Benjamin Poulter, Daniel Ricciuto, Kevin Schaefer, Xiaoying Shi, Bo Tao, Hanqin Tian, Weile Wang, Yaxing Wei, Jia Yang, Ning Zeng

Chaoqun (Crystal) Lu

Multimodel ensembles (MME) are commonplace in Earth system modeling. Here we perform MME integration using a 10-member ensemble of terrestrial biosphere models (TBMs) from the Multiscale synthesis and Terrestrial Model Intercomparison Project (MsTMIP). We contrast optimal (skill based for present-day carbon cycling) versus naïve (“one model-one vote”) integration. MsTMIP optimal and naïve mean land sink strength estimates (−1.16 versus −1.15 Pg C per annum respectively) are statistically indistinguishable. This holds also for grid cell values and extends to gross uptake, biomass, and net ecosystem productivity. TBM skill is similarly indistinguishable. The added complexity of skill-based integration does not materially change …

Go to article

Global Patterns And Controls Of Soil Organic Carbon Dynamics As Simulated By Multiple Terrestrial Biosphere Models: Current Status And Future Directions, Hanqin Tian, Chaoqun (Crystal) Lu, Jia Yang, Kamaljit Banger, Denorah N. Huntzinger, Christopher R. Schwalm, Anna M. Michalak, Robert Cook, Philippe Ciais, Daniel Hayes, Maoyi Huang, Akihiko Ito, Atul K. Jain, Huimin Lei, Jiafu Mao, Shufen Pan, Wilfred M. Post, Shushi Peng, Benjamin Poulter, Wei Ren, Daniel Ricciuto, Kevin Schaefer, Xiaoying Shi, Bo Tao, Weile Wang, Yaxing Wei, Qichun Yang, Bowen Zhang, Ning Zeng Jun 2015

Global Patterns And Controls Of Soil Organic Carbon Dynamics As Simulated By Multiple Terrestrial Biosphere Models: Current Status And Future Directions, Hanqin Tian, Chaoqun (Crystal) Lu, Jia Yang, Kamaljit Banger, Denorah N. Huntzinger, Christopher R. Schwalm, Anna M. Michalak, Robert Cook, Philippe Ciais, Daniel Hayes, Maoyi Huang, Akihiko Ito, Atul K. Jain, Huimin Lei, Jiafu Mao, Shufen Pan, Wilfred M. Post, Shushi Peng, Benjamin Poulter, Wei Ren, Daniel Ricciuto, Kevin Schaefer, Xiaoying Shi, Bo Tao, Weile Wang, Yaxing Wei, Qichun Yang, Bowen Zhang, Ning Zeng

Chaoqun (Crystal) Lu

Soil is the largest organic carbon (C) pool of terrestrial ecosystems, and C loss from soil accounts for a large proportion of land-atmosphere C exchange. Therefore, a small change in soil organic C (SOC) can affect atmospheric carbon dioxide (CO2) concentration and climate change. In the past decades, a wide variety of studies have been conducted to quantify global SOC stocks and soil C exchange with the atmosphere through site measurements, inventories, and empirical/process-based modeling. However, these estimates are highly uncertain, and identifying major driving forces controlling soil C dynamics remains a key research challenge. This study has compiled century-long …

Go to article

Low-Cost Rural Surface Alternatives: Demonstration Project, Cheng Li, Jeramy C. Ashlock, David White, Pavana Vennapusa Jun 2015

Low-Cost Rural Surface Alternatives: Demonstration Project, Cheng Li, Jeramy C. Ashlock, David White, Pavana Vennapusa

Jeramy C. Ashlock

A field demonstration project was conducted in Hamilton County, Iowa to compare the relative performance, durability, and costs of several stabilization methods for preventing or mitigating freeze-thaw damage to granular surfaced roads.

Go to article

Low-Cost Rural Surface Alternatives: Demonstration Project, Cheng Li, Jeramy C. Ashlock, David White, Pavana Vennapusa Jun 2015

Low-Cost Rural Surface Alternatives: Demonstration Project, Cheng Li, Jeramy C. Ashlock, David White, Pavana Vennapusa

Jeramy C. Ashlock

The goals of this project were to implement several stabilization methods for preventing or mitigating freeze-thaw damage to granular surfaced roads and identify the most effective and economical methods for the soil and climate conditions of Iowa. Several methods and technologies identified as potentially suitable for Iowa were selected from an extensive analysis of existing literature provided with Iowa Highway Research Board (IHRB) Project TR-632.Using the selected methods, demonstration sections were constructed in Hamilton County on a heavily traveled two-mile section of granular surfaced road that required frequent maintenance during previous thawing periods. Construction procedures and costs of the demonstration …

Go to article

“Parenting: It’S A Life” - Understanding Iowa Students’ Views Of Teen Parenthood, Brittni Wessner Blais, Randie D. Camp M.S., Emily D. Sorenson, Nicola Ervin, Kathryn Goudy-Haht Apr 2015

“Parenting: It’S A Life” - Understanding Iowa Students’ Views Of Teen Parenthood, Brittni Wessner Blais, Randie D. Camp M.S., Emily D. Sorenson, Nicola Ervin, Kathryn Goudy-Haht

Randie D. Camp, M.S.

No abstract provided.

Go to article

Designing A Child Participated Building Evaluation Tool: A Review Of Literature (Naghmeh Pak And Andrea Wheeler), Andrea S. Wheeler, Naghmeh Pak Apr 2015

Designing A Child Participated Building Evaluation Tool: A Review Of Literature (Naghmeh Pak And Andrea Wheeler), Andrea S. Wheeler, Naghmeh Pak

Andrea S. Wheeler

Because the foundation of an individual’s health and well-being is laid in their childhood, evaluating health and comfort factors in the environments in which children live is essential. Children have a different perspective on design quality and define comfort differently from that of adults, but schools are generally designed without consultation with children. School is a designed setting that a child resides in on a daily basis, and the United Nations Convention on the Rights of the Child argues that it is simply a matter of a child’s right to be consulted about his or her day-to-day environment, “the child’s …

Go to article

Large Fluxes And Rapid Turnover Of Mineral-Associated Carbon Across Topographic Gradients In A Humid Tropical Forest: Insights From Paired 14c Analysis, Steven J. Hall, G. Mcnicol, T. Natake, W. L. Silver Apr 2015

Large Fluxes And Rapid Turnover Of Mineral-Associated Carbon Across Topographic Gradients In A Humid Tropical Forest: Insights From Paired 14c Analysis, Steven J. Hall, G. Mcnicol, T. Natake, W. L. Silver

Steven J. Hall

It has been proposed that the large soil carbon (C) stocks of humid tropical forests result predominantly from C stabilization by reactive minerals, whereas oxygen (O2) limitation of decomposition has received much less attention. We examined the importance of these factors in explaining patterns of C stocks and turnover in the Luquillo Experimental Forest, Puerto Rico, using radiocarbon (14C) measurements of contemporary and archived samples. Samples from ridge, slope, and valley positions spanned three soil orders (Ultisol, Oxisol, Inceptisol) representative of humid tropical forests, and differed in texture, reactive metal content, O2 availability, and root biomass. Mineral-associated C comprised the …

Go to article

"Sustainable And Green Architecture" (With Stephen Hoff And Naghmeh Pak) Celt Teaching Poster Symposium, Campanile Room Of The Memorial Union, Andrea S. Wheeler, Stephen Hoff, Naghmeh Pak Mar 2015

"Sustainable And Green Architecture" (With Stephen Hoff And Naghmeh Pak) Celt Teaching Poster Symposium, Campanile Room Of The Memorial Union, Andrea S. Wheeler, Stephen Hoff, Naghmeh Pak

Andrea S. Wheeler

The CELT Teaching Partners program was an opportunity to develop a successful teaching approach for a new class: ARCH 558 Sustainable and Green Architecture, which I offered for the first time in Fall 2014. I adopted team-based and collaborative learning as a method especially appropriate for sustainable designers. This required team activities on research problems to solve, but the final research essay assignment remained an individual activity. The problem the class presented was one of evaluating the benefit of teamwork within the course objectives. In Fall Semester 2014 I inherited a course that had not been offered for more than …

Go to article

Global Methane And Nitrous Oxide Emissions From Terrestrial Ecosystems Due To Multiple Environmental Changes, Hanqin Tian, Guangsheng Chen, Chaoqun (Crystal) Lu, Xiaofeng Xu, Wei Ren, Bowen Zhang, Kamaljit Banger, Bo Tao, Shufen Pan, Mingliang Liu, Chi Zhang, Lori Bruhwiler, Steven Wofsy Mar 2015

Global Methane And Nitrous Oxide Emissions From Terrestrial Ecosystems Due To Multiple Environmental Changes, Hanqin Tian, Guangsheng Chen, Chaoqun (Crystal) Lu, Xiaofeng Xu, Wei Ren, Bowen Zhang, Kamaljit Banger, Bo Tao, Shufen Pan, Mingliang Liu, Chi Zhang, Lori Bruhwiler, Steven Wofsy

Chaoqun (Crystal) Lu

Greenhouse gas (GHG)-induced climate change is among the most pressing sustainability challenges facing humanity today, posing serious risks for ecosystem health. Methane (CH4) and nitrous oxide (N2O) are the two most important GHGs after carbon dioxide (CO2), but their regional and global budgets are not well known. In this study, we applied a process-based coupled biogeochemical model to concurrently estimate the magnitude and spatial and temporal patterns of CH4 and N2O fluxes as driven by multiple environmental changes, including climate variability, rising atmospheric CO2, increasing nitrogen deposition, tropospheric ozone pollution, land use change, and nitrogen fertilizer use. The estimated CH4 …

Go to article

Assessment Of Nondestructive Testing Technologies For Quality Control/Quality Assurance Of Asphalt Mixtures - Tech Transfer Summary, Shibin Lin, Jeramy C. Ashlock, Hanjun Kim, Jeremy Nash, Hosin David Lee, R. Christopher Williams Mar 2015

Assessment Of Nondestructive Testing Technologies For Quality Control/Quality Assurance Of Asphalt Mixtures - Tech Transfer Summary, Shibin Lin, Jeramy C. Ashlock, Hanjun Kim, Jeremy Nash, Hosin David Lee, R. Christopher Williams

Jeramy C. Ashlock

Asphalt pavements suffer various failures due to insufficient quality within their design lives. The American Association of State Highway and Transportation Officials (AASHTO) Mechanistic-Empirical Pavement Design Guide (MEPDG) has been proposed to improve pavement quality through quantitative performance prediction. Evaluation of the actual performance (quality) of pavements requires in situ nondestructive testing (NDT) techniques that can accurately measure the most critical, objective, and sensitive properties of pavement systems. The purpose of this study is to assess existing as well as promising new NDT technologies for quality control/quality assurance (QC/QA) of asphalt mixtures. Specifically, this study examined field measurements of density …

Go to article

Comparison Of Spatial Association Approaches For Landscape Mapping Of Soil Organic Carbon Stocks, Bradley A. Miller, S. Koszinski, M. Wehrhan, M. Sommer Mar 2015

Comparison Of Spatial Association Approaches For Landscape Mapping Of Soil Organic Carbon Stocks, Bradley A. Miller, S. Koszinski, M. Wehrhan, M. Sommer

Bradley A Miller

The distribution of soil organic carbon (SOC) can be variable at small analysis scales, but consideration of its role in regional and global issues demands the mapping of large extents. There are many different strategies for mapping SOC, among which is to model the variables needed to calculate the SOC stock indirectly or to model the SOC stock directly. The purpose of this research is to compare direct and indirect approaches to mapping SOC stocks from rule-based, multiple linear regression models applied at the landscape scale via spatial association. The final products for both strategies are high-resolution maps of SOC …

Go to article

Green School, Designing For Comfort And Beyond…, Andrea S. Wheeler, Naghmeh Pak, Evan Jeanblanc Feb 2015

Green School, Designing For Comfort And Beyond…, Andrea S. Wheeler, Naghmeh Pak, Evan Jeanblanc

Andrea S. Wheeler

Comfort is defined through human senses; sight, hearing, smell, touch, and taste. Each sense can lead to a greater or lesser degree of comfort. However, children experience comfort differently than adults. They experience spaces differently and have different knowledge about the performance of a building than adult users; they can also have a perspective on design quality unlike that of the architect. School is a designed environment that a child lives in for over 6 hours a day; it is it is thus argued simply a matter of a child’s right to be consulted about his or her day-to-day environment. …

Go to article

Impact Of Multi-Scale Predictor Selection For Modeling Soil Properties, Bradley A. Miller, Sylvia Koszinski, Marc Wehrhan, Michael Sommer Feb 2015

Impact Of Multi-Scale Predictor Selection For Modeling Soil Properties, Bradley A. Miller, Sylvia Koszinski, Marc Wehrhan, Michael Sommer

Bradley A Miller

Applying a data mining tool used regularly in digital soil mapping, this research focuses on the optimal inclusion of predictors for soil–landscape modeling by utilizing as wide of a pool of variables as possible. Predictor variables for digital soil mapping are often chosen on the basis of data availability and the researcher's expert knowledge. Predictor variables commonly overlooked include alternative analysis scales for land-surface derivatives and additional remote sensing products. For this study, a pool of 412 potential predictors was assembled, which included qualitative location classes, elevation, land-surface derivatives (with a wide range of analysis scales), hydrologic indicators, as well …

Go to article

Synthetic Strategies For Tailoring The Physicochemical And Magnetic Properties Of Hydrophobic Magnetic Ionic Liquids, Omprakash Nacham, Kevin D. Clark, Honglian Yu, Jared L. Anderson Jan 2015

Synthetic Strategies For Tailoring The Physicochemical And Magnetic Properties Of Hydrophobic Magnetic Ionic Liquids, Omprakash Nacham, Kevin D. Clark, Honglian Yu, Jared L. Anderson

Jared L. Anderson

Magnetic ionic liquids (MILs) are a subclass of ionic liquids (ILs) containing paramagnetic components and are readily manipulated by an external magnetic field. Due to their hydrophilic nature, very few applications of MILs in aqueous systems have been reported. In this study, three general classes of hydrophobic MILs including monocationic, symmetrical/unsymmetrical dicationic, and symmetrical/unsymmetrical tricationic MILs were synthesized and characterized. By tuning the structure of the MIL, various physicochemical properties including water solubility, magnetic susceptibility, and melting point were regulated. MILs synthesized with the benzimidazolium cation were shown to exhibit lower water solubility (0.1% (w/v)) when compared to those containing …

Go to article

Extraction Of Dna By Magnetic Ionic Liquids: Tunable Solvents For Rapid And Selective Dna Analysis, Kevin D. Clark, Omprakash Nacham, Honglian Yu, Tianhao Li, Melissa M. Yamsek, Donald R. Ronning, Jared L. Anderson Jan 2015

Extraction Of Dna By Magnetic Ionic Liquids: Tunable Solvents For Rapid And Selective Dna Analysis, Kevin D. Clark, Omprakash Nacham, Honglian Yu, Tianhao Li, Melissa M. Yamsek, Donald R. Ronning, Jared L. Anderson

Jared L. Anderson

DNA extraction represents a significant bottleneck in nucleic acid analysis. In this study, hydrophobic magnetic ionic liquids (MILs) were synthesized and employed as solvents for the rapid and efficient extraction of DNA from aqueous solution. The DNA-enriched microdroplets were manipulated by application of a magnetic field. The three MILs examined in this study exhibited unique DNA extraction capabilities when applied toward a variety of DNA samples and matrices. High extraction efficiencies were obtained for smaller single-stranded and double-stranded DNA using the benzyltrioctylammonium bromotrichloroferrate(III) ([(C8)3BnN+][FeCl3Br–]) MIL, while the dicationic 1,12-di(3-hexadecylbenzimidazolium)dodecane bis[(trifluoromethyl)sulfonyl]imide bromotrichloroferrate(III) ([(C16BnIM)2C122+][NTf2–, FeCl3Br–]) MIL produced higher extraction efficiencies for larger …

Go to article

Language Learning Policy Through The Lens Of Language As A Problem, As A Right, And As A Resource., Carla A. Mcnelly Dr. Jan 2015

Language Learning Policy Through The Lens Of Language As A Problem, As A Right, And As A Resource., Carla A. Mcnelly Dr.

Carla A McNelly

Richard Ruíz first developed the framework of language as a problem, as a right, and as a resource as a way of engaging how we examine language learning policies. This lens remains a useful tool in examining our national language learning policies. This article incorporates the academic work of additional scholars to define the United States’ practices, policies, and outcomes of language as a problem, as a right, and as a resource. Through the use of this framework, we realize that our nation’s bilingual education programs are generating monolingual and limited bilingual students. Equipped with an understanding that our nation …

Go to article

Sociality Increases Juvenile Survival After A Catastrophic Event In The Feral Horse (Equus Caballus), Cassandra M.V. Nuñez, James S. Adelman, Daniel I. Rubenstein Jan 2015

Sociality Increases Juvenile Survival After A Catastrophic Event In The Feral Horse (Equus Caballus), Cassandra M.V. Nuñez, James S. Adelman, Daniel I. Rubenstein

Cassandra M.V. Nuñez

In several social species, adult associations have been linked to individual fitness. Less is known about offspring associations and the mechanisms by which they may influence fitness. We investigate the effects of sociality on juvenile survival in feral horses (Equus caballus). We use foal degree (number of associates) and foal weight (number of interactions) to assess sociality’s importance to foal survival of a catastrophic event, the gathering and removal of 40% of the horse population. We found that 1) foal degree was a better predictor of foal survival than was foal weight; 2) following the gather, foals with access to …

Go to article

Advancing Computational Toxicology In A Regulatory Setting: A Selected Review Of The Accomplishments Of Gilman D. Veith (1944–2013), Steven P. Bradbury, Christine L. Russom, Patricia K. Schmieder, Terry W. Schultz, Robert Diderich, Charles M. Auer Jan 2015

Advancing Computational Toxicology In A Regulatory Setting: A Selected Review Of The Accomplishments Of Gilman D. Veith (1944–2013), Steven P. Bradbury, Christine L. Russom, Patricia K. Schmieder, Terry W. Schultz, Robert Diderich, Charles M. Auer

Steven P. Bradbury

With the passing of Dr. Gilman D. Veith on August 18, 2013, the research community lost one of its true visionaries in the development and implementation of alternative in silico and in vitro toxicology models in human health and ecological risk assessment. His career spanned more than four decades, during which he repeatedly demonstrated vision and leadership to advance alternative testing and assessment research and to guide the adoption of research accomplishments into U.S. and international chemical regulatory programs. His ability to advance toxicological and environmental exposure research, and associated quantitative structure– activity relationships (QSARs), for application in environmental regulatory …

Go to article

Next Last