Malcolm Williamson | University of Arkansas (original) (raw)

Papers by Malcolm Williamson

Scientific Reports, 2021

Understanding the interactions among agricultural processes, soil, and plants is necessary for op... more Understanding the interactions among agricultural processes, soil, and plants is necessary for optimizing crop yield and productivity. This study focuses on developing effective monitoring and analysis methodologies that estimate key soil and plant properties. These methodologies include data acquisition and processing approaches that use unmanned aerial vehicles (UAVs) and surface geophysical techniques. In particular, we applied these approaches to a soybean farm in Arkansas to characterize the soil–plant coupled spatial and temporal heterogeneity, as well as to identify key environmental factors that influence plant growth and yield. UAV-based multitemporal acquisition of high-resolution RGB (red–green–blue) imagery and direct measurements were used to monitor plant height and photosynthetic activity. We present an algorithm that efficiently exploits the high-resolution UAV images to estimate plant spatial abundance and plant vigor throughout the growing season. Such plant charac...

ABSTRACT Natural gas production in the Fayetteville shale area (Arkansas, USA) might create criti... more ABSTRACT Natural gas production in the Fayetteville shale area (Arkansas, USA) might create critical levels of water discharge due to diversion of surface water used for horizontal hydraulic fracturing. In fact, each well requires between 12000 m3 and 26500 m3 of water for hydraulic fracturing and the number of wells is expected to grow in the future. This usage, combined with drinking and farming needs, could pose water resource management concerns.

BACKGROUND: The Mississippi Alluvial Valley (MAV) once contained the most extensive and diverse l... more BACKGROUND: The Mississippi Alluvial Valley (MAV) once contained the most extensive and diverse lowland forest in North America. The complexity and productivity of the ecosystem were the result of the influx of massive amounts of outwash from episodes of continental glaciation that occurred north of the region, as well as the dynamic behavior of the large rivers that have repeatedly migrated across the landscape, eroding and depositing sediments and regularly flooding millions of acres. Beginning with the arrival of the first European settlers, the rivers have been stabilized and prevented from inundating most of the former floodplain, and agriculture has largely replaced the native vegetation. The deforestation of the MAV has contributed to a variety of problems such as the extinction of wildlife species and pollution of receiving waters, including the Gulf of Mexico. Various government policies and private initiatives have been implemented to reverse this damage through restoratio...

Mapping COVID-19 in Space and Time, 2021

Connections between human health and geographic location have been recognized since at least the ... more Connections between human health and geographic location have been recognized since at least the time of the ancient Greek physician Hippocrates (Hippocrates 1849). While certainly not a new concept, efforts to study human health and disease using geospatial data and analyses have only recently begun to attract widespread attention outside of a few specialized disciplines (Barrett 2000). In particular, the COVID-19 pandemic has brought this relatively small but growing research field into the public spotlight and generated unprecedented demand for maps and analyses, with the result that more researchers and data scientists than ever before are using geospatial data. The associated high profile geospatial analyses of COVID-19 data have amplified questions of reproducibility and replicability (R&R) and related issues such as trust, privacy, and quality across the information technology (IT)-intensive sciences. Many complex geospatial R&R issues can be simplified or better understood by a focus on who has (or should have) access to associated geospatial provenance information (Tullis and Kar 2020) which is defined below.

IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium, 2018

This study presents preliminary observations of the first year of a crop monitoring experiment oc... more This study presents preliminary observations of the first year of a crop monitoring experiment occurred in two soybean agriculture fields in the Arkansas delta. The project focuses on developing image processing and data integration techniques for UAV-based images to optimize advanced farm management such as soil microbial amendments. In particular, we present an effective algorithm that can use high-resolution UAV images efficiently to estimate sprout density and plant vigor/health throughout the growing season. Such plant characterization is extremely important for the identification of anomalous areas and provide easily interpretable information for a better decision making. We also present an integrative analysis of UAV-data with geophysical data and harvesting data, which shows high correlation between persistent spatial pattern of soil, plant phenology/growth, and crop yield.

2012 Oceans, 2012

ABSTRACT The potential visual impact of offshore wind facilities on coastal lands has emerged as ... more ABSTRACT The potential visual impact of offshore wind facilities on coastal lands has emerged as a major concern for the siting and future development of these facilities in Europe and the United States. The visibility and visual contrast of offshore wind facilities depend on complex interactions among facility size, turbine size and color, distance from shore, lighting, and weather and atmospheric conditions, as well as other factors that affect overall visibility. However, little systemic study of visibility and visual contrast of offshore wind facilities in real seascape settings has been conducted. As a result, there is uncertainty about the potential effects of offshore wind facilities on sensitive visual resource areas in coastal regions, such as national seashores, historic sites, and trail corridors. As part of a research study sponsored by the U.S. Department of the Interior's Bureau of Ocean Energy Management, an assessment of the visibility and visual contrast of 11 utility-scale offshore wind facilities was conducted in the United Kingdom in August and September of 2011. The observed facilities ranged from 25 to 140 turbines and were located within 5.5-52.0 km (3.4-32.3 mi) of 29 coastal viewpoints. Turbine power output ranged from 2.0 to 5.0 MW, with blade tip heights ranging from 113.5 to 153 m (372 to 502 ft). Study objectives included identifying the maximum distances at which the facilities could be seen from the coastal viewpoints in both daytime and night-time views and assessing the effect of distance on the degree of visual contrast associated with the facilities. Observers included a landscape architect, a geospatial visualization developer, and an archaeologist. For each facility, the observers recorded data about weather and lighting conditions, photographed the facilities at different focal lengths, and used a numeric scale to assess the facilities' degree of visibility. A total of 48 daytime observations of 11 offshore wind facilities were made, - nd an additional 6 observations were made at night. Weather and visibility conditions varied widely during the 10-day field study. In the course of this study, under favorable but not exceptional viewing conditions, moderate-sized offshore wind facilities were frequently found to be visible at distances exceeding 21 mi (34 km); they were visible at a maximum distance of 43 km (27 mi), as seen from an elevated viewpoint. With few exceptions, regardless of facility size or lighting conditions, on days with good visibility, offshore wind facilities were judged to be major foci of visual attention at distances of 16 km (10 mi) or less, suggesting potentially high levels of visual impact for sensitive viewers. Smaller wind facilities (25-48 turbines) were generally judged to be easily visible at distances of 23-24 km (14-15 mi). Larger offshore wind facilities (100 or more turbines) were judged likely to be seen easily by casual observers as far away as 29 km (18 mi), and were visible with extended or concentrated viewing at distances greater than 40 km (25 mi). That these distances are greater than those reported in previous studies is likely a function of the long-term trend toward larger offshore wind facilities with more and larger turbines than those assessed in previous studies. Turbine blade movement was visible in 42 of the 49 daytime observations, at distances as great as 42 km (26 mi) as seen from an elevated viewpoint, and was observed routinely at distances of 34 km (21 mi) or less. At night, aerial hazard navigation lighting was visible at distances greater than 39 km (24 mi). The study suggests that as countries begin siting offshore wind facilities with hundreds or even thousands of large wind turbines, there is potential for impacts on sensitive visual resources in coastal areas at greater distances than past studies have indicated.

This report describes work performed during the initial period of the project "Probabilistic Risk... more This report describes work performed during the initial period of the project "Probabilistic Risk Based Decision Support for Oil and Gas Exploration and Production Facilities in Sensitive Ecosystems." The specific region that is within the scope of this study is the Fayetteville Shale Play. This is an unconventional, tight formation, natural gas play that currently has approximately 1.5 million acres under lease, primarily to Southwestern Energy Incorporated and Chesapeake Energy Incorporated. The currently active play encompasses a region from approximately Fort Smith, AR east to Little Rock, AR approximately 50 miles wide (from North to South). The initial estimates for this field put it almost on par with the Barnett Shale play in Texas. It is anticipated that thousands of wells will be drilled during the next several years; this will entail installation of massive support infrastructure of roads and pipelines, as well as drilling fluid disposal pits and infrastructure to handle millions of gallons of fracturing fluids. This project focuses on gas production in Arkansas as the test bed for application of proactive risk management decision support system for natural gas exploration and production. The activities covered in this report include meetings with representative stakeholders, development of initial content and design for an educational web site, and development and preliminary testing of an interactive mapping utility designed to provide users with information that will allow avoidance of sensitive areas during the development of the Fayetteville Shale Play. These tools have been presented to both regulatory and industrial stakeholder groups, and their feedback has been incorporated into the project.

Geological Society of America Abstracts with Programs, Nov 6, 2012

In June 2011, a 4,200 square meter dinosaur trackway site was exposed within Lower Cretaceous str... more In June 2011, a 4,200 square meter dinosaur trackway site was exposed within Lower Cretaceous strata (De Queen Limestone) revealing sauropod tracks and trackways and the first documented occurrence of theropod tracks and trackways in southwest Arkansas. The sauropod tracks were most similar to the ichnogenus Brontopodus. The theropod tracks were tentatively referred to the ichnogenus Eubrontes and attributed to the Lower Cretaceous carnosaur, Acrocanthosaurus atokensis, based on interpretations of similar ...

American Journal of Physical Anthropology, 1998

Most functional analyses of primate tooth form have been limited to linear or area measurements. ... more Most functional analyses of primate tooth form have been limited to linear or area measurements. Such studies have offered but a limited glimpse at differences in occlusal relief among taxa. Such differences in dental topography may relate to tooth function and, so, have considerable implications for the inference of diet from fossil teeth. In this article, we describe a technique to model and compare primate molars in three dimensions using Geographic Resources Analysis Support System (GRASS) software. We examine unworn lower second molars of three extant hominoids with known differences in diet (Gorilla gorilla, Pan troglodytes, and Pongo pygmaeus), and two fossil forms, (Afropithecus turkanesis and Dryopithecus laietanus). First, we obtained approximately 400 landmarks on the occlusal surfaces of each tooth using an electromagnetic digitizer. Raster "terrain models" of occlusal surfaces were then created by interpolation of the coordinate data. We used GRASS terrain analysis automated techniques to quantify the volumes and slopes of individual cusps. We also used the GRASS watershed technique to identify the volume of liquid that would accumulate in each tooth's basin (a measure of basin area), and the directions and intensity of drainage over the occlusal surface. In sum, GRASS shows considerable potential for the characterization and comparison of tooth surfaces. Furthermore, techniques described here are not limited to the study of teeth, but may be broadly applicable to studies of skulls, joints, and other biological structures.

Mammalian tooth form reflects the material proper-ties of foods. Much research has focused on rel... more Mammalian tooth form reflects the material proper-ties of foods. Much research has focused on relation-ships between aspects of dental morphology and diet. Understanding these relationships allows us to infer feeding adaptations from the teeth of fossil forms. Most such studies have focused on unworn (rather than worn) teeth because these are easier to characterize and com-pare among species. Nevertheless, tooth shape changes with wear, and most fossil teeth are worn. How does wear affect functional efficiency? Can dental morphol-ogy of worn teeth be used to infer diets of fossil species? The study described here presents a new way to exam-ine the shapes of worn teeth so that we may begin to answer these important questions.

Applications of Small Unmanned Aircraft Systems, 2019

Part of the Administrative Law Commons, Climate Commons, Energy and Utilities Law Commons, Energy... more Part of the Administrative Law Commons, Climate Commons, Energy and Utilities Law Commons, Energy Policy Commons, Environmental Law Commons, Environmental Policy Commons, Hydraulic Engineering Commons, Natural Resources and Conservation Commons, Natural Resources Law Commons, Natural Resources Management and Policy Commons, Oil, Gas, and Energy Commons, Oil, Gas, and Mineral Law Commons, State and Local Government Law Commons, Technology and Innovation Commons, Water Law Commons, and the Water Resource Management Commons

Advances in Archaeological Practice

Conducting archaeological fieldwork increasingly relies on “high-tech” instruments. These include... more Conducting archaeological fieldwork increasingly relies on “high-tech” instruments. These include such technologies as portable X-ray diffraction; ground penetrating radar; high-precision global navigation satellite system (GNSS) receivers; laser scanners; multispectral, thermal, lidar, and hyperspectral instruments on Uncrewed Aerial Vehicles (UAVs); and many others. Using these devices internationally can present complex issues with export regulations and the potential for duties and value-added taxes. In short, there are many regulations affecting the movement of these devices across international borders. In the past, archaeologists had interactions with customs personnel and faced the complexities of import and export laws at the end of a project, as they dealt with the issues of taking samples or artifacts out of a country for study. Today's archaeologists must be prepared before they even begin their travel to ensure that their equipment and software can travel overseas. ...

We are developing a fixed-frame system employing a small Unmanned Aerial System (sUAS) for perfor... more We are developing a fixed-frame system employing a small Unmanned Aerial System (sUAS) for performing low elevation, fast and affordable aeromagnetic surveys over geothermal or volcanic areas. We tested two different magnetometer systems (scalar and vector) that are both designed for sUAS surveys. The sensor systems are each fixed on a frame at a distance of 0.5 m below the sUAS. Magnetic signals originating from the sUAS that interfere with the intended measurements of geologic features must be removed from the recordings, a process typically referred to as magnetic compensation. This correction requires performing specific maneuvers in a magnetically low gradient area at the beginning of each survey. We employed different compensation methods for the two systems which we applied to data collected during field experiments where we flew a grid pattern over a ~5000m area. We compare the different magnetometer systems and their compensation methods. Both sensors yield relatively small...

Advances in Archaeological Practice

In the original publication of this article, the middle initial of the second author was incorrec... more In the original publication of this article, the middle initial of the second author was incorrect. The authors apologize for this error. The original article has since been corrected.

Advances in Archaeological Practice

Archaeologists have long recognized that precise three-dimensional coordinates are critical for r... more Archaeologists have long recognized that precise three-dimensional coordinates are critical for recording objects and features across sites and landscapes. Traditionally, for relatively small areas, an optical transit or, more recently, an electronic distance measurement device (EDM) has been used to acquire these three-dimensional points. While effective, such systems have significant limitations in that they require a clear line of site. Real-time kinematic (RTK) GPS/GNSS systems (Global Positioning System/Global Navigation Satellite Systems) have been available for well over a decade, and can provide quick and accurate point measurements over a wide area without many of the limitation of older technologies. The cost of such systems, however, has generally been prohibitive for archaeologists, and so their use has been rare. Recently, a new generation of low-cost systems has become available, making this technology more accessible to a wider user base. This article describes the us...

PloS one, 2018

LIDAR-based analyses of the first theropod dinosaur trackways known from the state of Arkansas, U... more LIDAR-based analyses of the first theropod dinosaur trackways known from the state of Arkansas, USA are reported. The trackways were found on a limestone bedding plane in the Albian De Queen Formation in an active gypsum quarry. Because limited access precluded thorough field study, fieldwork focused on preserving the entire site digitally with ground-based LIDAR, and detailed measurements were later taken digitally from point cloud data. The site contains eight tridactyl trackways associated with sauropod trackways and numerous isolated tracks. Although there appear to be two different tridactyl morphotypes, we show that the tracks are all likely from a single species of trackmaker. We apply a simple method of estimating substrate consistency by comparing the differences between true track dimensions and apparent track dimensions. The tridactyl tracks at the southern end of the site are preserved with significantly greater differences in true vs. apparent dimensions and are shallow...

Over the past three decades, extensive field studies of wetland plant communities have been condu... more Over the past three decades, extensive field studies of wetland plant communities have been conducted in the Mississippi Alluvial Valley. These field studies have been carried out for various purposes under the auspices of federal and state research programs or in conjunction with Corps of Engineers project planning efforts. In the process, a wetland site classification approach has evolved based on hydrology, soils, and geomorphic setting. The research data and classification system have been recently used for a new purpose: to create a set of Potential Natural Vegetation (PNV) maps covering more than 26,000 square miles within the region. The purpose of PNV maps is to serve as blueprints for restoration planning and prioritization. Due to the fact that the hydrology of the landscape has been permanently changed by major flood control projects, the PNV maps do not represent the distribution of the original, pre-settlement vegetation. Rather, they identify the natural communities that are appropriate to the modern altered site conditions. By using these maps, persons interested in restoring particular tracts of land can identify the plant communities appropriate to the conditions present. Conversely, individuals interested in restoring particular plant communities can identify parts of the landscape that can support each respective type. The PNV maps are available for use in a Geographic Information System, where a range of complex restoration scenarios (such as the development of wildlife travel corridors or refuge areas) can be explored efficiently, and alternative approaches can be compared to one another in terms of costs and ecological effectiveness. This report is one of six Field Atlases that present the same data in a downloadable, printable format at a scale of 1 in. = 1 mile. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

The dimensions of archaeology are "form," "temporal locus" and "spatial locus." They are "an aspe... more The dimensions of archaeology are "form," "temporal locus" and "spatial locus." They are "an aspect or property of the subject matter which requires its own special measuring device" Albert Spaulding 1960

Wetlands, 2009

Alternating braided and meandering stream flow regimes throughout the Quaternary Period have left... more Alternating braided and meandering stream flow regimes throughout the Quaternary Period have left a subtly complex landscape of depositional features within the Mississippi Alluvial Valley (MAV). Prior to European settlement, those variations produced tremendous spatial complexity and diversity within vast forested wetlands and extensive fire-maintained prairies and savannas, with the distribution of specific plant communities largely reflecting abiotic site characteristics such as geomorphology, soils, and hydrology. Agricultural development, river engineering, flood protection, and drainage projects over the past century have destroyed most of the natural vegetation and obscured the patterns of plant community distribution. Recent studies have established hydrogeomorphic criteria for wetland classification over a large part of the MAV. Detailed, spatially explicit geomorphology and soils data are available for the entire MAV, and hydrologic mapping has been completed in many areas. Thus, even in areas that are currently in agriculture, the tools exist to adapt the hydrogeomorphic classification and to develop maps of potential plant community distribution based on abiotic characteristics of sites. These Potential Natural Vegetation maps provide an indication of the multi-scale complexity that once characterized the MAV, and serve as planning tools for ecosystem restoration.

Scientific Reports, 2021

Understanding the interactions among agricultural processes, soil, and plants is necessary for op... more Understanding the interactions among agricultural processes, soil, and plants is necessary for optimizing crop yield and productivity. This study focuses on developing effective monitoring and analysis methodologies that estimate key soil and plant properties. These methodologies include data acquisition and processing approaches that use unmanned aerial vehicles (UAVs) and surface geophysical techniques. In particular, we applied these approaches to a soybean farm in Arkansas to characterize the soil–plant coupled spatial and temporal heterogeneity, as well as to identify key environmental factors that influence plant growth and yield. UAV-based multitemporal acquisition of high-resolution RGB (red–green–blue) imagery and direct measurements were used to monitor plant height and photosynthetic activity. We present an algorithm that efficiently exploits the high-resolution UAV images to estimate plant spatial abundance and plant vigor throughout the growing season. Such plant charac...

ABSTRACT Natural gas production in the Fayetteville shale area (Arkansas, USA) might create criti... more ABSTRACT Natural gas production in the Fayetteville shale area (Arkansas, USA) might create critical levels of water discharge due to diversion of surface water used for horizontal hydraulic fracturing. In fact, each well requires between 12000 m3 and 26500 m3 of water for hydraulic fracturing and the number of wells is expected to grow in the future. This usage, combined with drinking and farming needs, could pose water resource management concerns.

BACKGROUND: The Mississippi Alluvial Valley (MAV) once contained the most extensive and diverse l... more BACKGROUND: The Mississippi Alluvial Valley (MAV) once contained the most extensive and diverse lowland forest in North America. The complexity and productivity of the ecosystem were the result of the influx of massive amounts of outwash from episodes of continental glaciation that occurred north of the region, as well as the dynamic behavior of the large rivers that have repeatedly migrated across the landscape, eroding and depositing sediments and regularly flooding millions of acres. Beginning with the arrival of the first European settlers, the rivers have been stabilized and prevented from inundating most of the former floodplain, and agriculture has largely replaced the native vegetation. The deforestation of the MAV has contributed to a variety of problems such as the extinction of wildlife species and pollution of receiving waters, including the Gulf of Mexico. Various government policies and private initiatives have been implemented to reverse this damage through restoratio...

Mapping COVID-19 in Space and Time, 2021

Connections between human health and geographic location have been recognized since at least the ... more Connections between human health and geographic location have been recognized since at least the time of the ancient Greek physician Hippocrates (Hippocrates 1849). While certainly not a new concept, efforts to study human health and disease using geospatial data and analyses have only recently begun to attract widespread attention outside of a few specialized disciplines (Barrett 2000). In particular, the COVID-19 pandemic has brought this relatively small but growing research field into the public spotlight and generated unprecedented demand for maps and analyses, with the result that more researchers and data scientists than ever before are using geospatial data. The associated high profile geospatial analyses of COVID-19 data have amplified questions of reproducibility and replicability (R&R) and related issues such as trust, privacy, and quality across the information technology (IT)-intensive sciences. Many complex geospatial R&R issues can be simplified or better understood by a focus on who has (or should have) access to associated geospatial provenance information (Tullis and Kar 2020) which is defined below.

IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium, 2018

This study presents preliminary observations of the first year of a crop monitoring experiment oc... more This study presents preliminary observations of the first year of a crop monitoring experiment occurred in two soybean agriculture fields in the Arkansas delta. The project focuses on developing image processing and data integration techniques for UAV-based images to optimize advanced farm management such as soil microbial amendments. In particular, we present an effective algorithm that can use high-resolution UAV images efficiently to estimate sprout density and plant vigor/health throughout the growing season. Such plant characterization is extremely important for the identification of anomalous areas and provide easily interpretable information for a better decision making. We also present an integrative analysis of UAV-data with geophysical data and harvesting data, which shows high correlation between persistent spatial pattern of soil, plant phenology/growth, and crop yield.

2012 Oceans, 2012

ABSTRACT The potential visual impact of offshore wind facilities on coastal lands has emerged as ... more ABSTRACT The potential visual impact of offshore wind facilities on coastal lands has emerged as a major concern for the siting and future development of these facilities in Europe and the United States. The visibility and visual contrast of offshore wind facilities depend on complex interactions among facility size, turbine size and color, distance from shore, lighting, and weather and atmospheric conditions, as well as other factors that affect overall visibility. However, little systemic study of visibility and visual contrast of offshore wind facilities in real seascape settings has been conducted. As a result, there is uncertainty about the potential effects of offshore wind facilities on sensitive visual resource areas in coastal regions, such as national seashores, historic sites, and trail corridors. As part of a research study sponsored by the U.S. Department of the Interior's Bureau of Ocean Energy Management, an assessment of the visibility and visual contrast of 11 utility-scale offshore wind facilities was conducted in the United Kingdom in August and September of 2011. The observed facilities ranged from 25 to 140 turbines and were located within 5.5-52.0 km (3.4-32.3 mi) of 29 coastal viewpoints. Turbine power output ranged from 2.0 to 5.0 MW, with blade tip heights ranging from 113.5 to 153 m (372 to 502 ft). Study objectives included identifying the maximum distances at which the facilities could be seen from the coastal viewpoints in both daytime and night-time views and assessing the effect of distance on the degree of visual contrast associated with the facilities. Observers included a landscape architect, a geospatial visualization developer, and an archaeologist. For each facility, the observers recorded data about weather and lighting conditions, photographed the facilities at different focal lengths, and used a numeric scale to assess the facilities' degree of visibility. A total of 48 daytime observations of 11 offshore wind facilities were made, - nd an additional 6 observations were made at night. Weather and visibility conditions varied widely during the 10-day field study. In the course of this study, under favorable but not exceptional viewing conditions, moderate-sized offshore wind facilities were frequently found to be visible at distances exceeding 21 mi (34 km); they were visible at a maximum distance of 43 km (27 mi), as seen from an elevated viewpoint. With few exceptions, regardless of facility size or lighting conditions, on days with good visibility, offshore wind facilities were judged to be major foci of visual attention at distances of 16 km (10 mi) or less, suggesting potentially high levels of visual impact for sensitive viewers. Smaller wind facilities (25-48 turbines) were generally judged to be easily visible at distances of 23-24 km (14-15 mi). Larger offshore wind facilities (100 or more turbines) were judged likely to be seen easily by casual observers as far away as 29 km (18 mi), and were visible with extended or concentrated viewing at distances greater than 40 km (25 mi). That these distances are greater than those reported in previous studies is likely a function of the long-term trend toward larger offshore wind facilities with more and larger turbines than those assessed in previous studies. Turbine blade movement was visible in 42 of the 49 daytime observations, at distances as great as 42 km (26 mi) as seen from an elevated viewpoint, and was observed routinely at distances of 34 km (21 mi) or less. At night, aerial hazard navigation lighting was visible at distances greater than 39 km (24 mi). The study suggests that as countries begin siting offshore wind facilities with hundreds or even thousands of large wind turbines, there is potential for impacts on sensitive visual resources in coastal areas at greater distances than past studies have indicated.

This report describes work performed during the initial period of the project "Probabilistic Risk... more This report describes work performed during the initial period of the project "Probabilistic Risk Based Decision Support for Oil and Gas Exploration and Production Facilities in Sensitive Ecosystems." The specific region that is within the scope of this study is the Fayetteville Shale Play. This is an unconventional, tight formation, natural gas play that currently has approximately 1.5 million acres under lease, primarily to Southwestern Energy Incorporated and Chesapeake Energy Incorporated. The currently active play encompasses a region from approximately Fort Smith, AR east to Little Rock, AR approximately 50 miles wide (from North to South). The initial estimates for this field put it almost on par with the Barnett Shale play in Texas. It is anticipated that thousands of wells will be drilled during the next several years; this will entail installation of massive support infrastructure of roads and pipelines, as well as drilling fluid disposal pits and infrastructure to handle millions of gallons of fracturing fluids. This project focuses on gas production in Arkansas as the test bed for application of proactive risk management decision support system for natural gas exploration and production. The activities covered in this report include meetings with representative stakeholders, development of initial content and design for an educational web site, and development and preliminary testing of an interactive mapping utility designed to provide users with information that will allow avoidance of sensitive areas during the development of the Fayetteville Shale Play. These tools have been presented to both regulatory and industrial stakeholder groups, and their feedback has been incorporated into the project.

Geological Society of America Abstracts with Programs, Nov 6, 2012

In June 2011, a 4,200 square meter dinosaur trackway site was exposed within Lower Cretaceous str... more In June 2011, a 4,200 square meter dinosaur trackway site was exposed within Lower Cretaceous strata (De Queen Limestone) revealing sauropod tracks and trackways and the first documented occurrence of theropod tracks and trackways in southwest Arkansas. The sauropod tracks were most similar to the ichnogenus Brontopodus. The theropod tracks were tentatively referred to the ichnogenus Eubrontes and attributed to the Lower Cretaceous carnosaur, Acrocanthosaurus atokensis, based on interpretations of similar ...

American Journal of Physical Anthropology, 1998

Most functional analyses of primate tooth form have been limited to linear or area measurements. ... more Most functional analyses of primate tooth form have been limited to linear or area measurements. Such studies have offered but a limited glimpse at differences in occlusal relief among taxa. Such differences in dental topography may relate to tooth function and, so, have considerable implications for the inference of diet from fossil teeth. In this article, we describe a technique to model and compare primate molars in three dimensions using Geographic Resources Analysis Support System (GRASS) software. We examine unworn lower second molars of three extant hominoids with known differences in diet (Gorilla gorilla, Pan troglodytes, and Pongo pygmaeus), and two fossil forms, (Afropithecus turkanesis and Dryopithecus laietanus). First, we obtained approximately 400 landmarks on the occlusal surfaces of each tooth using an electromagnetic digitizer. Raster "terrain models" of occlusal surfaces were then created by interpolation of the coordinate data. We used GRASS terrain analysis automated techniques to quantify the volumes and slopes of individual cusps. We also used the GRASS watershed technique to identify the volume of liquid that would accumulate in each tooth's basin (a measure of basin area), and the directions and intensity of drainage over the occlusal surface. In sum, GRASS shows considerable potential for the characterization and comparison of tooth surfaces. Furthermore, techniques described here are not limited to the study of teeth, but may be broadly applicable to studies of skulls, joints, and other biological structures.

Mammalian tooth form reflects the material proper-ties of foods. Much research has focused on rel... more Mammalian tooth form reflects the material proper-ties of foods. Much research has focused on relation-ships between aspects of dental morphology and diet. Understanding these relationships allows us to infer feeding adaptations from the teeth of fossil forms. Most such studies have focused on unworn (rather than worn) teeth because these are easier to characterize and com-pare among species. Nevertheless, tooth shape changes with wear, and most fossil teeth are worn. How does wear affect functional efficiency? Can dental morphol-ogy of worn teeth be used to infer diets of fossil species? The study described here presents a new way to exam-ine the shapes of worn teeth so that we may begin to answer these important questions.

Applications of Small Unmanned Aircraft Systems, 2019

Part of the Administrative Law Commons, Climate Commons, Energy and Utilities Law Commons, Energy... more Part of the Administrative Law Commons, Climate Commons, Energy and Utilities Law Commons, Energy Policy Commons, Environmental Law Commons, Environmental Policy Commons, Hydraulic Engineering Commons, Natural Resources and Conservation Commons, Natural Resources Law Commons, Natural Resources Management and Policy Commons, Oil, Gas, and Energy Commons, Oil, Gas, and Mineral Law Commons, State and Local Government Law Commons, Technology and Innovation Commons, Water Law Commons, and the Water Resource Management Commons

Advances in Archaeological Practice

Conducting archaeological fieldwork increasingly relies on “high-tech” instruments. These include... more Conducting archaeological fieldwork increasingly relies on “high-tech” instruments. These include such technologies as portable X-ray diffraction; ground penetrating radar; high-precision global navigation satellite system (GNSS) receivers; laser scanners; multispectral, thermal, lidar, and hyperspectral instruments on Uncrewed Aerial Vehicles (UAVs); and many others. Using these devices internationally can present complex issues with export regulations and the potential for duties and value-added taxes. In short, there are many regulations affecting the movement of these devices across international borders. In the past, archaeologists had interactions with customs personnel and faced the complexities of import and export laws at the end of a project, as they dealt with the issues of taking samples or artifacts out of a country for study. Today's archaeologists must be prepared before they even begin their travel to ensure that their equipment and software can travel overseas. ...

We are developing a fixed-frame system employing a small Unmanned Aerial System (sUAS) for perfor... more We are developing a fixed-frame system employing a small Unmanned Aerial System (sUAS) for performing low elevation, fast and affordable aeromagnetic surveys over geothermal or volcanic areas. We tested two different magnetometer systems (scalar and vector) that are both designed for sUAS surveys. The sensor systems are each fixed on a frame at a distance of 0.5 m below the sUAS. Magnetic signals originating from the sUAS that interfere with the intended measurements of geologic features must be removed from the recordings, a process typically referred to as magnetic compensation. This correction requires performing specific maneuvers in a magnetically low gradient area at the beginning of each survey. We employed different compensation methods for the two systems which we applied to data collected during field experiments where we flew a grid pattern over a ~5000m area. We compare the different magnetometer systems and their compensation methods. Both sensors yield relatively small...

Advances in Archaeological Practice

In the original publication of this article, the middle initial of the second author was incorrec... more In the original publication of this article, the middle initial of the second author was incorrect. The authors apologize for this error. The original article has since been corrected.

Advances in Archaeological Practice

Archaeologists have long recognized that precise three-dimensional coordinates are critical for r... more Archaeologists have long recognized that precise three-dimensional coordinates are critical for recording objects and features across sites and landscapes. Traditionally, for relatively small areas, an optical transit or, more recently, an electronic distance measurement device (EDM) has been used to acquire these three-dimensional points. While effective, such systems have significant limitations in that they require a clear line of site. Real-time kinematic (RTK) GPS/GNSS systems (Global Positioning System/Global Navigation Satellite Systems) have been available for well over a decade, and can provide quick and accurate point measurements over a wide area without many of the limitation of older technologies. The cost of such systems, however, has generally been prohibitive for archaeologists, and so their use has been rare. Recently, a new generation of low-cost systems has become available, making this technology more accessible to a wider user base. This article describes the us...

PloS one, 2018

LIDAR-based analyses of the first theropod dinosaur trackways known from the state of Arkansas, U... more LIDAR-based analyses of the first theropod dinosaur trackways known from the state of Arkansas, USA are reported. The trackways were found on a limestone bedding plane in the Albian De Queen Formation in an active gypsum quarry. Because limited access precluded thorough field study, fieldwork focused on preserving the entire site digitally with ground-based LIDAR, and detailed measurements were later taken digitally from point cloud data. The site contains eight tridactyl trackways associated with sauropod trackways and numerous isolated tracks. Although there appear to be two different tridactyl morphotypes, we show that the tracks are all likely from a single species of trackmaker. We apply a simple method of estimating substrate consistency by comparing the differences between true track dimensions and apparent track dimensions. The tridactyl tracks at the southern end of the site are preserved with significantly greater differences in true vs. apparent dimensions and are shallow...

Over the past three decades, extensive field studies of wetland plant communities have been condu... more Over the past three decades, extensive field studies of wetland plant communities have been conducted in the Mississippi Alluvial Valley. These field studies have been carried out for various purposes under the auspices of federal and state research programs or in conjunction with Corps of Engineers project planning efforts. In the process, a wetland site classification approach has evolved based on hydrology, soils, and geomorphic setting. The research data and classification system have been recently used for a new purpose: to create a set of Potential Natural Vegetation (PNV) maps covering more than 26,000 square miles within the region. The purpose of PNV maps is to serve as blueprints for restoration planning and prioritization. Due to the fact that the hydrology of the landscape has been permanently changed by major flood control projects, the PNV maps do not represent the distribution of the original, pre-settlement vegetation. Rather, they identify the natural communities that are appropriate to the modern altered site conditions. By using these maps, persons interested in restoring particular tracts of land can identify the plant communities appropriate to the conditions present. Conversely, individuals interested in restoring particular plant communities can identify parts of the landscape that can support each respective type. The PNV maps are available for use in a Geographic Information System, where a range of complex restoration scenarios (such as the development of wildlife travel corridors or refuge areas) can be explored efficiently, and alternative approaches can be compared to one another in terms of costs and ecological effectiveness. This report is one of six Field Atlases that present the same data in a downloadable, printable format at a scale of 1 in. = 1 mile. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

The dimensions of archaeology are "form," "temporal locus" and "spatial locus." They are "an aspe... more The dimensions of archaeology are "form," "temporal locus" and "spatial locus." They are "an aspect or property of the subject matter which requires its own special measuring device" Albert Spaulding 1960

Wetlands, 2009

Alternating braided and meandering stream flow regimes throughout the Quaternary Period have left... more Alternating braided and meandering stream flow regimes throughout the Quaternary Period have left a subtly complex landscape of depositional features within the Mississippi Alluvial Valley (MAV). Prior to European settlement, those variations produced tremendous spatial complexity and diversity within vast forested wetlands and extensive fire-maintained prairies and savannas, with the distribution of specific plant communities largely reflecting abiotic site characteristics such as geomorphology, soils, and hydrology. Agricultural development, river engineering, flood protection, and drainage projects over the past century have destroyed most of the natural vegetation and obscured the patterns of plant community distribution. Recent studies have established hydrogeomorphic criteria for wetland classification over a large part of the MAV. Detailed, spatially explicit geomorphology and soils data are available for the entire MAV, and hydrologic mapping has been completed in many areas. Thus, even in areas that are currently in agriculture, the tools exist to adapt the hydrogeomorphic classification and to develop maps of potential plant community distribution based on abiotic characteristics of sites. These Potential Natural Vegetation maps provide an indication of the multi-scale complexity that once characterized the MAV, and serve as planning tools for ecosystem restoration.