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Articles 151 - 180 of 7340

Full-Text Articles in Physical Sciences and Mathematics

Are Plant–Soil Feedbacks Caused By Many Weak Microbial Interactions?, Julia K. Aaronson, Andrew Kulmatiski, Leslie E. Forero, Josephine Grenzer, Jeanette M. Norton Oct 2023

Are Plant–Soil Feedbacks Caused By Many Weak Microbial Interactions?, Julia K. Aaronson, Andrew Kulmatiski, Leslie E. Forero, Josephine Grenzer, Jeanette M. Norton

Wildland Resources Student Research

We used high-throughput sequencing and multivariate analyses to describe soil microbial community composition in two four-year field plant–soil feedback (PSF) experiments in Minnesota, USA and Jena, Germany. In descending order of variation explained, microbial community composition differed between the two study sites, among years, between bulk and rhizosphere soils, and among rhizosphere soils cultivated by different plant species. To try to identify soil organisms or communities that may cause PSF, we correlated plant growth responses with the microbial community composition associated with different plants. We found that plant biomass was correlated with values on two multivariate axes. These multivariate axes …


On The Computability Of Primitive Recursive Functions By Feedforward Artificial Neural Networks, Vladimir A. Kulyukin Oct 2023

On The Computability Of Primitive Recursive Functions By Feedforward Artificial Neural Networks, Vladimir A. Kulyukin

Computer Science Faculty and Staff Publications

We show that, for a primitive recursive function h(x, t), where x is a n-tuple of natural numbers and t is a natural number, there exists a feedforward artificial neural network 𝔑(x, t), such that for any n-tuple of natural numbers z and a positive natural number m, the first m + 1 terms of the sequence {h(z, t)} are the same as the terms of the tuple (𝔑(z, 0), ... ,𝔑(z, m)).


Contemporary Art Authentication With Large-Scale Classification, Todd Dobbs, Abdullah-Al-Raihan Nayeem, Isaac Cho, Zbigniew Ras Oct 2023

Contemporary Art Authentication With Large-Scale Classification, Todd Dobbs, Abdullah-Al-Raihan Nayeem, Isaac Cho, Zbigniew Ras

Computer Science Faculty and Staff Publications

Art authentication is the process of identifying the artist who created a piece of artwork and is manifested through events of provenance, such as art gallery exhibitions and financial transactions. Art authentication has visual influence via the uniqueness of the artist’s style in contrast to the style of another artist. The significance of this contrast is proportional to the number of artists involved and the degree of uniqueness of an artist’s collection. This visual uniqueness of style can be captured in a mathematical model produced by a machine learning (ML) algorithm on painting images. Art authentication is not always possible …


Utahns Strongly Support Renewable Energy Sources Such As Solar And Wind, Elizabeth Brunner, Stacia Ryder Oct 2023

Utahns Strongly Support Renewable Energy Sources Such As Solar And Wind, Elizabeth Brunner, Stacia Ryder

Utah People and Environment Poll (UPEP)

Utah was the fastest-growing state in the nation by population between 2010 and 2020.1 This growing population is bringing increased demand for energy. The build out of Utah's electric vehicle (EV) infrastructure, with the state aiming to site electric vehicle charging stations at least every 50 miles along its interstate highway system by the end of 2025, will also increase energy demand. This growth will equate to increased carbon emissions if Utah does not change its electricity mix, which is currently composed of primarily carbon-emitting sources. As of 2022 (see Figure 1), 53% of Utah's total electricity net generation …


Using Assessments To Promote Growth Mindset In College Algebra, Hannah M. Lewis, Kady Schneiter, David Lane Tait Sep 2023

Using Assessments To Promote Growth Mindset In College Algebra, Hannah M. Lewis, Kady Schneiter, David Lane Tait

Mathematics and Statistics Faculty Publications

Scientific evidence highlights the positive impact of a growth mindset on student achievement. Students with a growth mindset view errors and obstacles as opportunities for growth and welcome challenges and the opportunity to learn from their mistakes. Much has been written about promoting growth mindset through lectures and attitudes, however, assessments can also be an important avenue for encouraging a growth mindset in students. In this paper, we describe how we used assessments to promote growth mindset in a college algebra class. In the sections that follow, we discuss the need for these assessments and the principles that underly their …


A Novel Fuzzy Relative-Position-Coding Transformer For Breast Cancer Diagnosis Using Ultrasonography, Yanhui Guo, Ruquan Jiang, Xin Gu, Heng-Da Cheng, Harish Garg Sep 2023

A Novel Fuzzy Relative-Position-Coding Transformer For Breast Cancer Diagnosis Using Ultrasonography, Yanhui Guo, Ruquan Jiang, Xin Gu, Heng-Da Cheng, Harish Garg

Computer Science Faculty and Staff Publications

Breast cancer is a leading cause of death in women worldwide, and early detection is crucial for successful treatment. Computer-aided diagnosis (CAD) systems have been developed to assist doctors in identifying breast cancer on ultrasound images. In this paper, we propose a novel fuzzy relative-position-coding (FRPC) Transformer to classify breast ultrasound (BUS) images for breast cancer diagnosis. The proposed FRPC Transformer utilizes the self-attention mechanism of Transformer networks combined with fuzzy relative-position-coding to capture global and local features of the BUS images. The performance of the proposed method is evaluated on one benchmark dataset and compared with those obtained by …


The Irrigation Efficiency Trap: Rational Farm-Scale Decisions Can Lead To Poor Hydrologic Outcomes At The Basin Scale, Christina N. Morrisett, Robert W. Van Kirk, London O. Bernier, Andrea L. Holt, Chloe B. Perel, Sarah E. Null Aug 2023

The Irrigation Efficiency Trap: Rational Farm-Scale Decisions Can Lead To Poor Hydrologic Outcomes At The Basin Scale, Christina N. Morrisett, Robert W. Van Kirk, London O. Bernier, Andrea L. Holt, Chloe B. Perel, Sarah E. Null

Watershed Sciences Faculty Publications

Agricultural irrigation practices have changed through time as technology has enabled more efficient conveyance and application. In some agricultural regions, irrigation can contribute to incidental aquifer recharge important for groundwater return flows to streams. The Henrys Fork Snake River, Idaho (United States) overlies a portion of the Eastern Snake Plain Aquifer, where irrigated agriculture has occurred for over a century. Using irrigator interviews, aerial and satellite imagery, and statistical streamflow analysis, we document the impact of farm-scale decisions on basin-scale hydrology. Motivated to improve economic efficiency, irrigators began converting from surface to center-pivot sprinkler irrigation in the 1950s, with rapid …


Nalidarturbopauseshear, Titus Yuan Aug 2023

Nalidarturbopauseshear, Titus Yuan

Browse all Datasets

The USU Na lidar has been upgraded to be able to measure temperature and winds in the lower thermosphere up to ~ 115 km routinely. The new capability, coupled with the existing nightglow instruments at USU, enables the investigation of the extreme large wind and shears in this region and their correlation to the atmospheric gravity waves activities in the upper mesosphere.


A Simple Method For Determining Shallow Charge Distributions In Dielectrics Via Pulsed Electroacoustic Measurements, Zachary Gibson, J. R. Dennison Aug 2023

A Simple Method For Determining Shallow Charge Distributions In Dielectrics Via Pulsed Electroacoustic Measurements, Zachary Gibson, J. R. Dennison

Journal Articles

The understanding of charge dynamics in dielectric materials is paramount in mitigating electrostatic discharge events for spacecraft. The most critical spacecraft charging events are found to result from incident electrons in the energy range of 10 keV to 50 keV. The charge embedded in dielectric materials in this energy range are deposited a distance into the material on the order of a few to tens of microns. One way to measure and understand the deposited charge is via pulsed electroacoustic measurements (PEA). However, the typical PEA spatial resolution of ~ 10 μm is not sufficient to resolve or discern charge …


A Multi-Tiered Assessment Of Primary Production In Great Salt Lake, Soren Brothers, Melissa Cobo, R. Douglas Ramsey, Wayne A. Wurtsbaugh, Erin N. Rivers Aug 2023

A Multi-Tiered Assessment Of Primary Production In Great Salt Lake, Soren Brothers, Melissa Cobo, R. Douglas Ramsey, Wayne A. Wurtsbaugh, Erin N. Rivers

Watershed Sciences Faculty Publications

Great Salt Lake (GSL) is the largest saline lake in the western hemisphere. Despite this, relatively little is known regarding ecological functioning within the lake, including detailed assessments of rates of primary productivity and ecosystem productivity. Analyses of primary production in GSL are complicated by the high heterogeneity of the system, including a broad salinity gradient from near-fresh conditions at the river confluences in Farmington and Bear River Bays to the hyper-saline conditions of the lake’s northwest arm (Gunnison Bay). Further complicating estimates of primary productivity is the possibility of high rates of benthic primary production (by benthic algae and …


A Neural-Network-Based Landscape Search Engine: Lse Wisconsin, Matthew Haffner, Matthew Dewitte, Papia F. Rozario, Gustavo A. Ovando-Montejo Aug 2023

A Neural-Network-Based Landscape Search Engine: Lse Wisconsin, Matthew Haffner, Matthew Dewitte, Papia F. Rozario, Gustavo A. Ovando-Montejo

Environment and Society Faculty Publications

The task of image retrieval is common in the world of data science and deep learning, but it has received less attention in the field of remote sensing. The authors seek to fill this gap in research through the presentation of a web-based landscape search engine for the US state of Wisconsin. The application allows users to select a location on the map and to find similar locations based on terrain and vegetation characteristics. It utilizes three neural network models—VGG16, ResNet-50, and NasNet—on digital elevation model data, and uses the NDVI mean and standard deviation for comparing vegetation data. The …


A Statewide Evaluation Of Fuel Treatment Effectiveness In Altering Wildfire Outcomes On Public Lands In Utah, Jamela Charmaine Thompson Aug 2023

A Statewide Evaluation Of Fuel Treatment Effectiveness In Altering Wildfire Outcomes On Public Lands In Utah, Jamela Charmaine Thompson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fuel treatments are land management activities that reduce living and dead flammable materials on the landscape to mitigate undesirable wildfire behavior and effects. Common treatments in the western United States include mechanical methods such as thinning and mastication, prescribed burns, and chemical methods, such as herbicide application. Treatments usually have multiple objectives, including reducing fire intensity, protecting natural and cultural resources, slowing or disrupting a potential future fire’s path, supporting ecosystem health, and reestablishing low to mid severity fire cycles in ecosystems. Although treatments can potentially modify fire behavior and ecological health, they generally cannot prevent fires from igniting, eliminate …


Comparative Study Of Clustering Techniques On Eye-Tracking In Dynamic 3d Virtual Environments, Scott Johnson Aug 2023

Comparative Study Of Clustering Techniques On Eye-Tracking In Dynamic 3d Virtual Environments, Scott Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Eye-tracking has been used for decades to understand how and why an individual focuses on particular objects, areas, and elements of space. A vast body of knowledge exists on how eye-tracking is measured. However, historically, eye-tracking has been predominately studied using 2D environments, with limited work in 3D environments. The purpose of this study is to identify which methods most accurately represent the areas that have captured the participant’s visual attention within a 3D dynamic environment. This will be completed by evaluating different clustering methods of fixations using a customized virtual reality tool that collects eye-tracking data. There exist several …


Physics-Guided Deep Learning For Solar Wind Modeling At L1 Point, Robert M. Johnson Aug 2023

Physics-Guided Deep Learning For Solar Wind Modeling At L1 Point, Robert M. Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Neural networks are adept at finding patterns that are too long and too small for humans to find in data. Usually, this power is used to generate predictions with greater accuracy than most alternative models. However, we can also use this power to understand more about the data we train these networks on. We do this by changing the data that the networks train on and the data they are tested on. This allows us to both control the maximum length of a pattern and to compare data between different groups, in our case, different solar cycles. This thesis is …


Influence Of Hydrologic History On Nitrogen Cycling In Lake Sediments, Emily Jainarain Aug 2023

Influence Of Hydrologic History On Nitrogen Cycling In Lake Sediments, Emily Jainarain

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Water quality is declining in freshwater lakes around the world due to environmental change and anthropogenic activities that threaten the physical, ecological, and geochemical integrity of freshwater ecosystems. Excess N and P in lakes can cause eutrophication, a major driver of water quality impairment that leads to excessive algal growth, or harmful algal blooms (HABs), and poses risks to recreation, fisheries, and public drinking water. Water level fluctuations in lakes are expected to become more frequent and intense as climate change increases periods of drought and alters precipitation patterns, and fluctuations may stimulate biogeochemical reactions in littoral sediments that add …


Overcoming Barriers To Aquatic Plant Restoration: Addressing Gaps In Species Identification And Planting Techniques In The Intermountain West, Kate A. Sinnott Aug 2023

Overcoming Barriers To Aquatic Plant Restoration: Addressing Gaps In Species Identification And Planting Techniques In The Intermountain West, Kate A. Sinnott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Aquatic ecosystems provide many critical and economically valuable benefits, including drinking water, food, recreational opportunities, and water supply for irrigation and agriculture. However, the health of these systems has been severely impacted by human activities such as pollution, land conversion, and introductions of harmful species. Restoring native aquatic plants can help reverse this damage and reestablish benefits, though it is not a common practice. With an objective to increase capacity for aquatic plant restoration in the Intermountain West, I identified and addressed two major barriers: 1) a lack of confidence in aquatic species identification among wetland professionals, and 2) underdeveloped …


Big Fish And More Of Them: Salmonid Habitat Availability, Quality, And Use Across Multiple Scales Within A River-Reservoir System, John S. Mclaren V Aug 2023

Big Fish And More Of Them: Salmonid Habitat Availability, Quality, And Use Across Multiple Scales Within A River-Reservoir System, John S. Mclaren V

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Reservoirs and their associated rivers provide water for agricultural and municipal uses, ecological benefits for fish and wildlife, and associated recreational activity. However, in the Greater Yellowstone Ecosystem climate change and population growth are putting pressure on water quality and supply, potentially damaging the unique and economically important coldwater trout habitat that these systems support. In this study, the author investigates the impact of changing water quality and supply on trout habitat quality, quantity, and selection to assist conservation goals in the Henry’s Fork Watershed in eastern Idaho. The study found that higher availability of cold-water refuge habitat in Island …


Effects Of Soil Amendments On Water Quality And Hydrologic Properties In Low Impact Development Systems, Lily Wetterlin Aug 2023

Effects Of Soil Amendments On Water Quality And Hydrologic Properties In Low Impact Development Systems, Lily Wetterlin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Low impact development (LID) systems are practices that use natural elements, such as soils and vegetation, to absorb and filter stormwater to protect water quality and aquatic habitats. Many LID designs use native soils; however, urban soils typically have a limited potential for infiltrating and treating stormwater. Incorporation of soil amendments, such as compost and biochar, into LID soils can improve the physical properties of soil. However, soil amendments may increase or decrease pollutants in the water leaving the site. A comparison of the effects of different types and application rates of amendments on water quality is necessary to determine …


Collaborative Development Of Utah's Outdoor Recreation Strategic Plan: Process And Findings From 14 Regional Workshops, Jordan W. Smith, Jake Powell, Casey Trout, Nate Trauntvein, Rachel Hall, Wayne Freimund Aug 2023

Collaborative Development Of Utah's Outdoor Recreation Strategic Plan: Process And Findings From 14 Regional Workshops, Jordan W. Smith, Jake Powell, Casey Trout, Nate Trauntvein, Rachel Hall, Wayne Freimund

Environment and Society Faculty Publications

Outdoor recreation within Utah is managed and provided through a patchwork of federal and state agencies as well as county and municipal governments. Each of these entities manages outdoor recreation following different mandates and internal objectives. Rarely has there been an opportunity for representatives from federal, state, county, and local governments to sit down, discuss the long-standing and emerging challenges they face, and collectively develop ideas about how to work towards less-disparate and more aligned outdoor recreation management systems. In late 2022 and early 2023, we convened hundreds of land managers, outdoor recreation and tourism professionals, and elected officials across …


Insights Into The Characteristics Of Outdoor Recreationists In Utah From A Statewide Survey, Jordan W. Smith, Nate Trauntvein, Casey Trout Aug 2023

Insights Into The Characteristics Of Outdoor Recreationists In Utah From A Statewide Survey, Jordan W. Smith, Nate Trauntvein, Casey Trout

Environment and Society Faculty Publications

Understanding the characteristics and preferences of outdoor recreationists in Utah can inform the administrative, funding, and management decisions of the many entities who provide outdoor recreation opportunities within the state. There is currently a lack of data on characteristics, preferences, and opinions of the state’s outdoor recreating public. As one component of the analysis supporting the development of the state’s outdoor recreation strategic plan, we launched a short online survey to begin to address this need. The survey was administered in spring of 2023 to an online panel of individuals who indicated that they are current residents of Utah and …


Generalizing Deep Learning Methods For Particle Tracing Using Transfer Learning, Shubham Gupta Aug 2023

Generalizing Deep Learning Methods For Particle Tracing Using Transfer Learning, Shubham Gupta

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Particle tracing is a very important method for scientific visualization of vector fields, but it is computationally expensive. Deep learning can be used to speed up particle tracing, but existing deep learning models are domain-specific. In this work, we present a methodology to generalize the use of deep learning for particle tracing using transfer learning. We demonstrate the performance of our approach through a series of experimental studies that address the most common simulation design scenarios: varying time span, Reynolds number, and problem geometry. The results show that our methodology can be effectively used to generalize and accelerate the training …


Signatures Of Black Holes, Alexandra B. Chanson Aug 2023

Signatures Of Black Holes, Alexandra B. Chanson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this defense I will describes three approaches to learn more about the relationship between the dynamics of black-holes and the distinctive signatures of a black hole systems: infinitesimal changes in the black hole background producing field excitations relating new fundamental black hole thermodynamic relations, mechanisms powering relativistic black hole jets and spontaneous symmetry breaking in five space-time dimensions, and physical signatures of black hole event horizons as conformal field theory duals (in both d=4,5 dimensional axisymmetric spacetimes).


An Interval-Valued Random Forests, Paul Gaona Partida Aug 2023

An Interval-Valued Random Forests, Paul Gaona Partida

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

There is a growing demand for the development of new statistical models and the refinement of established methods to accommodate different data structures. This need arises from the recognition that traditional statistics often assume the value of each observation to be precise, which may not hold true in many real-world scenarios. Factors such as the collection process and technological advancements can introduce imprecision and uncertainty into the data.

For example, consider data collected over a long period of time, where newer measurement tools may offer greater accuracy and provide more information than previous methods. In such cases, it becomes crucial …


Precise Determination Of Charge Distributions In Electron Irradiated Polymers Via Pulsed Electroacoustic Measurements With Applications To Spacecraft Charging, Zachary Gibson Aug 2023

Precise Determination Of Charge Distributions In Electron Irradiated Polymers Via Pulsed Electroacoustic Measurements With Applications To Spacecraft Charging, Zachary Gibson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding how charge builds up and moves around in materials that are highly insulating, such as dielectrics, is important for many applications from power transmission to spacecraft charging. The leading cause of issues in spacecraft due to interactions with the space environment is spacecraft charging. That is, the accumulation of charge on insulating materials leads to arcing and sparking aboard the spacecraft. The most critical charging occurs due to electrons in a particular energy range of 10-50 keV. Electrons with these energies can travel 1’s to 10’s of microns into relevant materials. To measure where the charge is embedded and …


Statistical Graph Quality Analysis Of Utah State University Master Of Science Thesis Reports, Ragan Astle Aug 2023

Statistical Graph Quality Analysis Of Utah State University Master Of Science Thesis Reports, Ragan Astle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Graphical software packages have become increasingly popular in our modern world, but there are concerns within the statistical visualization field about the default settings provided by these packages, which can make it challenging to create good quality graphs that align with standard graph principles. In this thesis, we investigate whether the quality of graphs from Utah State University (USU) Plan A Master of Science (MS) thesis reports from the years 1930 to 2019 was affected by the rise of graphical software packages. We collected all data stored on the USU Digital Commons website since November 2021 to determine the specific …


Stressor: An R Package For Benchmarking Machine Learning Models, Samuel A. Haycock Aug 2023

Stressor: An R Package For Benchmarking Machine Learning Models, Samuel A. Haycock

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Many discipline specific researchers need a way to quickly compare the accuracy of their predictive models to other alternatives. However, many of these researchers are not experienced with multiple programming languages. Python has recently been the leader in machine learning functionality, which includes the PyCaret library that allows users to develop high-performing machine learning models with only a few lines of code. The goal of the stressor package is to help users of the R programming language access the advantages of PyCaret without having to learn Python. This allows the user to leverage R’s powerful data analysis workflows, while simultaneously …


Using Natural Language Processing To Quantify The Efficacy Of Language Simplification As A Communication Strategy, Brian Nalley Aug 2023

Using Natural Language Processing To Quantify The Efficacy Of Language Simplification As A Communication Strategy, Brian Nalley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

People with communication disorders often experience difficulties being understood by unfamiliar listeners or in noisy environments. A common strategy for effectively communicating in these scenarios is to use simpler and more predictable language. Despite the prevalence of this strategy, there has been little to no research to date focused on the effectiveness of language simplification as a communication strategy. This study seeks to begin filling that gap by using natural language processing to determine whether speakers with early-stage Parkinson’s disease and age-matched neurotypical speakers are able to successfully simplify their language while still maintaining the original message.

Simplification was measured …


Constrained Route Optimization With Fleet Considerations For Electrified Heavy-Duty Freight Vehicles, Zarin Subah Shamma Aug 2023

Constrained Route Optimization With Fleet Considerations For Electrified Heavy-Duty Freight Vehicles, Zarin Subah Shamma

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Almost 75% of traffic-related emissions are caused by heavy-duty freight trucks and significantly impact neighborhoods, schools, and communities around shipping and distribution lines. With poor air quality and respiratory health, many children in at-risk and disadvantaged communities experience high rates of asthma, lower attendance in school, and lower concentration. This research creates to improve the impacts of heavy-duty electric freight by improving the route efficiency (in terms of energy, time, or route distance) of EV trucks. Our software and algorithms are tested in a simulation environment using data from several thousand fleet trucks operating in the Salt Lake City area. …


The Derivation Of Sodium Density In The Mesosphere And Lower Thermosphere From The Na Lidar Photon Counting Profiles, Xiaoqi Xi Aug 2023

The Derivation Of Sodium Density In The Mesosphere And Lower Thermosphere From The Na Lidar Photon Counting Profiles, Xiaoqi Xi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Derivation of Sodium (Na) number density from the Na lidar observations requires the in situ temperature and wind information because the absorption cross-section of the Na atom is a function of these dynamic parameters. The Na number density above ~ 110 km altitude was difficult to derive with the conventional algorithm, however. The standard output of the Na number density that utilizes the lidar-measured wind and temperature information falls short at ~ 110 km altitude and above due to the relatively large measurement uncertainties in the two critical parameters (low signal-to-noise ratio). Therefore, an innovative algorithm that may drive the …


Opening The Black Box: Soil Microbial Communities In Field-Based Plant-Soil Feedback Experiments, Julia Kate Aaronson Aug 2023

Opening The Black Box: Soil Microbial Communities In Field-Based Plant-Soil Feedback Experiments, Julia Kate Aaronson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plant-soil feedback is a process through which plants modify the properties of their associated soils, affecting their growth. PSF can play a key role in regulating plant growth and communities including altering plant invasion, rarity, and abundance. However, our understanding of the soil organisms that drive these plant growth responses is limited. Most studies treat soils as a ‘black box’ and do little to reveal which specific microbes or microbial communities may be responsible. This chapter examines two recent large PSF field experiments conducted in Minnesota, USA, and Jena, Germany. These experiments revealed that plants altered their soils, changing subsequent …