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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Natural Warning Signs of Tsunamis: Human Sensory Experience and Response to the 2004 Great Sumatra Earthquake and Tsunami in Thailand

Gregg, Chris, Houghton, Bruce F., Paton, Douglas, Lachman, Roy, Lachman, Janet, Johnston, David M., Wongbusarakum, Supin 01 June 2006 (has links)
Natural warning signs of tsunamis include ground shaking from earthquakes and unusual sea-level fluctuations, wave forms, and sounds. These signs can alert people to impending tsunamis, but no research has explored the recognizability of these signs or the social-cognitive factors that affect human behavioral response to them. Of 663 interviewees, 24% felt ground shaking during the earthquake; 69% saw something unusual about the ocean before the first wave reached land, mostly a receded shoreline; and 55% heard something unusual. Despite these levels of observation, most people did not evacuate. In fact, 65% saw other people in the danger zone at the time of the tsunami impact. Most respondents had to run for their lives but could not identify a safe place. There are major differences in experience among north, central, and southern coastal Thailand, reflecting social, topographical, and hydrological factors.
42

Developing a GIS Database for the Gray Fossil Site, Tennessee, Based on Modern Surveying

Nave, Jerry W., Ali, Tarig A., Wallace, Steven C. 01 December 2005 (has links)
The selection of an appropriate data acquisition method is a significant phase of GIS design, because the data determine the scale and accuracy of the analysis in the GIS. In the case of fossils, the method selected must provide precise mapping of all sizes of fossils uncovered at the paleontological site. Historically, paleontologists have used different methods to establish the approximate locations of fossils. A commonly used method consisted of string line grids and measuring tapes to provide arbitrary x, y and z coordinates. The maps produced using these methods often lacked accuracy were not replicable and did not provide any information about the conditions of the site. We studied how modern land surveying can enable fast accurate, replicable and precise mapping of fossils in 3D. First, the horizontal control monuments in the site were fixed using Global Positioning System (GPS), and a vertical control network was established by running an accurate, level loop from nearby state traverse control stations to the monuments within the site. Based on that, control stations were established throughout the project site, locating the existing geologic strata and providing a control network for the site base map. One challenge we faced was the design of a linkage mechanism that establishes unique identifiers for the fossils uncovered at the site. These identifiers are essential for determining fossil attributes and ensuring the consistency, integrity and completeness of the GIS database. The integration of modern land surveying techniques with GIS in this project has provided researchers with additional tools for spatial analysis, evaluation of site conditions and accurate relocation of fossils in the field.
43

Two New Carnivores From an Unusual Late Tertiary Forest Biota in Eastern North America

Wallace, Steven C., Wang, Xiaoming 30 September 2004 (has links)
Late Cenozoic terrestrial fossil records of North America are biased by a predominance of mid-latitude deposits, mostly in the western half of the continent. Consequently, the biological history of eastern North America, including the eastern deciduous forest, remains largely hidden. Unfortunately, vertebrate fossil sites from this vast region are rare, and few pertain to the critically important late Tertiary period, during which intensified global climatic changes took place. Moreover, strong phylogenetic affinities between the flora of eastern North America and eastern Asia clearly demonstrate formerly contiguous connections, but disparity among shared genera (eastern Asia-eastern North America disjunction) implies significant periods of separation since at least the Miocene epoch. Lacustrine sediments deposited within a former sinkhole in the southern Appalachian Mountains provide a rare example of a late Miocene to early Pliocene terrestrial biota from a forested ecosystem. Here we show that the vertebrate remains contained within this deposit represent a unique combination of North American and Eurasian taxa. A new genus and species of the red (lesser) panda (Pristinailurus bristoli), the earliest and most primitive so far known, was recovered. Also among the fauna are a new species of Eurasian badger (Arctomeles dimolodontus) and the largest concentration of fossil tapirs ever recorded. Cladistical analyses of the two new carnivores strongly suggest immigration events that were earlier than and distinct from previous records, and that the close faunal affinities between eastern North America and eastern Asia in the late Tertiary period are consistent with the contemporaneous botanical record.
44

New Evidence of the Earliest Domestic Dogs in the Americas

Perri, Angela, Widga, Chris, Lawler, Dennis, Martin, Terrance, Loebel, Thomas, Farnsworth, Kenneth, Kohn, Luci, Buenger, Brent 01 January 2019 (has links)
The domestication of dogs likely occurred in Eurasia by 16,000 years ago, and the initial peopling of the Americas potentially happened around the same time. Dogs were long thought to have accompanied the first migrations into the Americas, but conclusive evidence for Paleoindian dogs is lacking. In this study, the direct dating of two dogs from the Koster site (Greene County, Illinois) and a newly described dog from the Stilwell II site (Pike County, Illinois) to between 10,190 and 9,630 cal BP represents the earliest confirmed evidence of domestic dogs in the Americas and individual dog burials anywhere in the world. Analysis of these animals shows Early Archaic dogs were medium sized, lived active lifestyles, and exhibited significant morphological variation. Stable isotope analyses suggest diets dominated by terrestrial C3 resources and substantial consumption of riverine fish.
45

Iron and Manganese in Groundwater: Using Kriging and GIS to Locate High Concentrations in Buncombe County, North Carolina

Johnson, Crystal D., Nandi, Arpita, Joyner, T. Andrew, Luffman, Ingrid 01 January 2018 (has links)
For health, economic, and aesthetic reasons, allowable concentrations (as suggested by the United States Environmental Protection Agency) of the secondary contaminants iron (Fe) and manganese (Mn) found present in drinking water are 0.3 and 0.05 mg/L, respectively. Water samples taken from private drinking wells in rural communities within Buncombe County, North Carolina contain concentrations of these metals that exceed secondary water quality criteria. This study predicted the spatial distribution of Fe and Mn in the county, and evaluated the effect of site environmental factors (bedrock geology, ground elevation, saprolite thickness, and drinking water well depth) in controlling the variability of Fe and Mn in groundwater. A statistically significant correlation between Fe and Mn concentrations, attributable to bedrock geology, was identified. Prediction models were created using ordinary kriging and cokriging interpolation techniques to estimate the presence of Fe and Mn in groundwater where direct measurements are not possible. This same procedure can be used to estimate the trend of other contaminants in the groundwater in different areas with similar hydrogeological settings.
46

Nutrient Hotspots Through Time: A Field Guide to Modern and Fossil Taphonomy in East Tennessee

Keenan, Sarah W., Widga, Christopher, DeBruyn, Jennifer M., Schaeffer, Sean M. 29 March 2018 (has links)
Hotspots represent the ephemeral introduction of nutrients into an environment, and occur in both the modern and geologic past. The annual deposition of deciduous leaves in temperate forests, tree falls, animal excrement, and vertebrate carcass deposition all result in the pulsed introduction of nutrients to an ecosystem. Hotspots are critical for providing limiting nutrients, including nitrogen and carbon, to be incorporated into soil microbial biomass and plant biomass. For vertebrate carcasses, following the release of labile compounds from soft tissues, bones are often left behind, and provide a more recalcitrant reservoir of organic carbon and nitrogen, phosphorus, calcium, and, in some environments, water, for micro- and macro-fauna. Taphonomy-the physical, chemical, and biological processes following plant or animal death-studied in modern systems can be used to interpret hotspot processes operating in the past. East Tennessee is a region where studies of modern and fossil vertebrate hotspots have provided new insights into taphonomy. This guide describes two hotspot localities in east Tennessee-the Miocene-aged Gray Fossil Site in Gray, Tennessee, and the Anthropology Research Facility (“the Body Farm”) at the University of Tennessee, Knoxville, a human decomposition experimental site. The goal of this interdisciplinary field guide is to provide a view of nutrient hotspots from their formation in the modern to their preservation over geologic time.
47

A Hard Time to Date: The Scott County Pueblo (14sc1) and Puebloan Residents of the High Plains

Hill, Matthew E., Beck, Margaret E., Lengyel, Stacey, Trabert, Sarah J., Adair, Mary J. 01 January 2018 (has links)
During the seventeenth and eighteenth centuries, Puebloan women (if not entire families) were incorporated into Apache Dismal River communities in western Kansas. In at least one site (14SC1), Puebloan people lived in a small masonry pueblo. We evaluate the timing and nature of the Puebloan occupation at 14SC1 and its relationship to the Dismal River population at the site. We use a Bayesian analytical framework to evaluate different models of the pueblo's use history, constraining 12 radiocarbon dates by their stratigraphic data and then comparing this framework with different temporal models based on the historical record. We conclude that Dismal River people lived at 14SC1 prior to the appearance of Pueblo migrants, sometime between cal AD 1490 and 1650. Construction and early use of the pueblo by migrants from the Rio Grande valley occurred between cal AD 1630 and 1660, and the pueblo was closed by burning sometime between cal AD 1640 and 1690. Site 14SC1 lacks Rio Grande Glaze Ware, and its residents seem rarely to have engaged with the groups in the Southern Plains Macroeconomy. Our results contribute to studies of indigenous community formation and Puebloan residential mobility during the Spanish colonial period.
48

The Contribution of Late Pleistocene Megafauna Finds to Submerged Archaeology and the Interpretation of Ancient Coastal Landscapes

Claesson, Stefan, Baleka, Sina, Hofreiter, Michael, Widga, Chris 01 October 2017 (has links)
In 2013, two Pleistocene megafaunal remains, a single mammoth tooth and a partial juvenile mastodon mandible with teeth were recovered by a scallop-fisherman from two separate locations in the Merrimack River embayment off the coast of New Hampshire and Massachusetts. These specimens follow on previous finds by fishermen in the same locale over the last two decades, as well as numerous other offshore megafauna specimens and prehistoric stone tools, which have occurred in the Gulf of Maine for > 50 years. This paper examines the value and scientific sampling potential of previously recovered specimens and isolated finds in the Gulf of Maine. Specifically, it discusses isolated finds as indicators of submerged archaeological site preservation in the region, and as data sources that provide information about regional geomorphology, climate conditions, paleogenomics, and species extinctions in the terminal Pleistocene. Furthermore, submerged paleo-deltas, due to their depositional characteristics, are identified to have deeply buried paleosols with significant preservation potential for early human and environmental history. Therefore, the Merrimack River paleo-delta, and similar offshore submerged features elsewhere, serve not only as research opportunities into early human migration and settlement, but are also storehouses of climate and environmental data, which merit special recognition and protection from environmental and man-made activities that may impact or disturb these intact submerged landscapes.
49

Late Pleistocene Proboscidean Population Dynamics in the North American Midcontinent

Widga, Chris, Lengyel, Stacey N., Saunders, Jeffrey, Hodgins, Gregory, Walker, J. Douglas, Wanamaker, Alan D D. 01 October 2017 (has links)
Understanding megafaunal population dynamics is critical to testing and refining scenarios of how extinctions occurred during the terminal Pleistocene. Large-scale, collections-based, chronological and taphonomic analyses of midwestern Proboscidea suggest divergent population histories in mammoths and mastodons after the Last Glacial Maximum (LGM). Although extinction of both taxa occurred in the very late Bølling-Allerød (B-A) or early Younger Dryas (YD), Mammuthus is dominant during the LGM with a decreasing presence in the region until extirpation. Mammut americanum however, is absent during the LGM but becomes the dominant taxon during the subsequent B-A. Trace and physical evidence of large carnivores in post-LGM proboscidean assemblages is extremely rare, suggesting apex predators had minimal impact on mammoth and mastodon populations at this time. The ultimate mechanism(s) of extinction remain unclear; however, the wide geographical distribution of late Mammut and an increase in the frequency of multi-animal death assemblages is consistent with a large, destabilized population experiencing periodic boom-bust cycling at the end of the B-A. We suggest this pattern is due to the collapse of trophic controls on proboscidean populations prior to the LGM and a subsequent system-wide shift from top-down to bottom-up regulatory mechanisms in Proboscidea.
50

Fossil Mustela nigripes from Snake Creek Burial Cave, Nevada, and Implications for Black-Footed Ferret Paleoecology

Fox, Nathaniel S., Wallace, Steven C., Mead, Jim I. 01 July 2017 (has links)
Morphometric measurements were used to classify 11 mustelid dentaries from Snake Creek Burial Cave (SCBC), a late Pleistocene to early Holocene-aged paleontological locality in eastern Nevada, that were undifferentiated between Mustela nigripes (black-footed ferret) and Neovison vison (American mink) due to their similar size and morphology. We, therefore, classified the SCBC fossils using 10 linear measurements of the dentary using extant M. nigripes and N. vison as proxy. Discriminant function and principal component analyses grouped the 11 unknown SCBC specimens within extant M. nigripes exclusively. Confirmation of M. nigripes at SCBC is significant because Cynomys spp. (their primary prey source today) have not been found at this site or other nearby Great Basin localities. Occurrence of this now-endangered taxon among the SCBC paleofauna and review of additional localities lacking Cynomys suggest that several geographically and temporally discrete prehistoric M. nigripes populations were sustained by other small mammal taxa. If this inference is true, facilitating dietary diversity in reintroduced M. nigripes populations could improve the species' resilience to future adversities, including anthropogenic climate change.

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