7,635 research outputs found

    Magnetic Gradient Survey at the M. S. Roberts (41HE8) Site in Henderson County, Texas

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    The M. S. Roberts site is located in Henderson County, Texas and it represents one of the few known Caddo mound sites in the upper Neches River Basin in northeast Texas (Figure 1). The site is situated along Caddo Creek – an eastward-flowing tributary of the Neches River (Perttula et al. 2016; Perttula 2016; Perttula and Walters 2016). The site is located southeast of Athens, Texas. When first recorded, the single mound at the site was approximately 24 m long and 20 m wide and roughly 1.7 m in height (Pearce and Jackson 1931). Directly west of the mound was a large depression, which has since been mostly filled, and likely represents the borrow pit for mound fill. The mound is situated at the southern end of an elevated alluvial landform. The site was first reported to Dr. J. E. Pearce of the University of Texas in September 1931. In October of the same year, archaeologists from the University of Texas began investigating the mound and defining the extent of the associated settlement (Pearce and Jackson 1931). Researchers obtained a surface collection from the site and excavated an unknown number of trenches in the mound where portions of at least one burned and buried Caddo structure was identified. Their excavation notes document that the mound began as a 25 cm deposit of yellow sand constructed on the undisturbed brown sandy loam that defines the alluvial landform. A structure had been built on the yellow sand and then at some point had been burned. The burned structure was then covered with mound fill at least a meter in depth. Materials collected from the surface as part of the 1931 investigations indicate the presence of a Caddo habitation area surrounding the mound and suggest the site was occupied from the fourteenth to the early fifteenth centuries (Perttula et al. 2016; Perttula 2016; Perttula and Walters 2016). At that time, the landscape around the mound was a used as a cotton field and subject to extensive plowing. Today, the landscape is part of a residential ranch development where landowners are stewards of the site with a focus on preservation and research. In January 2015, with the permission of the landowners, renewed interested in the site began with a surface collection and the examination of the artifact collections from the 1931 work held by the Texas Archeological Research Laboratory (Perttula et al. 2016; Perttula 2016; Perttula and Walters 2016). A series of shovel tests and auger holes were then dug in the mound and surrounding habitation area in mid-2015. Shovel tests and auger holes documented organically-stained and charcoal-rich areas within the mound that were thought to represent the remains of several burned Caddo structures, and also identified non-mound habitation deposits at the site. An initial aerial survey was also conducted to map the landform topography, estimate the extent of the current mound dimensions and borrow pit, and to reconstruct changes in the shape and size of the mound since it was first recorded in 1931 (Perttula et al. 2016). The survey employed a small Unmanned Aerial Vehicle (UAV) to map the roughly 20-acre property surrounding the site at a 2 cm per pixel resolution. The aerial survey of the mound and surrounding landscape and the creation of a high-resolution digital elevation model reveal that the mound dimensions have changed significantly from what was reported in 1931 (Perttula et al. 2016). For example, aerial data document both the mound and borrow pit features and show that the mound measures 43 m North-South and 26 m East-West, and is roughly 1 meter above the surrounding terrace surface (Perttula et al. 2016). The aerial survey demonstrates that the mound has elongated over the last century since it was first recorded, likely related to historic landscape modification. In January 2016, the site was again revisited. The purpose of the fieldwork was to better define the spatial extent of archaeological deposits in the non-mounded habitation area and investigate the stratigraphy of mound deposits, identify cultural features in the mound, and hopefully obtain charred plant remains or unburned animal bones from these deposits for AMS dating. To help evaluate and identify the distribution of cultural features in the mound and the surrounding non-mounded habitation area, an area just over 1 hectare or 2.8 acres was surveyed using magnetic gradient and a second aerial survey was completed to refine the overall landscape topography (Figure 2). The magnetic gradient results document the subsurface location of at least two interpreted structures within the mound, the possible locations of three 1931 UT trenches, and several possible pit features proximate to the mound. The combination of aerial and geophysical data and the excavation results are revising our understanding of the archaeological remains and preservation conditions of the site

    Value and Outcome Uncertainty as Explanations for the WTA vs WTP Disparity: Theory and Experimental Evidence

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    This paper contributes to the widespread discussion of the sources of the divergence between WTA and WTP values. The paper reports on theoretical and empirical investigations which show that value and outcome uncertainty offer an explanation for this disparity. Given a set of hypotheses generated by the theory, the paper investigates the disparity using an inducedvalue experimental laboratory setting. The incentive-compatible Becker-DeGroot-Marshak mechanism is employed to elicit the WTP and WTA values. Two conclusions can be drawn from the empirical results. First, the WTA - WTP difference is generally increasing in both value and outcome uncertainty. Second, a re-contracting option reduces the disparity when it arises from value uncertainty. Key Words: Experimental, Uncertainty, WTP-WTA disparity

    Use and abuse of statistics in tobacco industry-funded research on standardised packaging

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    In this commentary we consider the validity of tobacco industry-funded research on the effects of standardised packaging in Australia. As the first country to introduce standardised packs, Australia is closely watched, and Philip Morris International has recently funded two studies into the impact of the measure on smoking prevalence. Both of these papers are flawed in conception as well as design but have nonetheless been widely publicised as cautionary tales against standardised pack legislation. Specifically, we focus on the low statistical significance of the analytical methods used and the assumption that standardised packaging should have an immediate large impact on smoking prevalence

    Active management of multi-service networks.

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    Future multiservice networks will be extremely large and complex. Novel management solutions will be required to keep the management costs reasonable. Active networking enables management to be delegated to network users as a large set of independent small scale management systems. A novel architecture for an active network based management solution for multiservice networking is presented

    Quality of life and building design in residential and nursing homes for older people

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    Older people living in residential and nursing care homes spend a large proportion of their time within the boundaries of the home, and may depend on the environment to compensate for their physical or cognitive frailties. Regulations and guidelines on the design of care buildings have accumulated over time with little knowledge of their impact on the quality of life of building users. The Design in Caring Environments Study (DICE) collected cross-sectional data on building design and quality of life in 38 care homes in and near Sheffield, Yorkshire. Quality of life was assessed using methods which included all residents regardless of their frailty, and staff morale was also assessed. The physical environment was measured on 11 user-related domains using a new tool, the Sheffield Care Environment Assessment Matrix (SCEAM). Significant positive associations were found between several aspects of the built environment and the residents' quality of life. There was evidence that a focus on safety and health requirements could be creating risk-averse environments which act against quality of life, particularly for the least frail residents. Staff morale was associated with attributes of a non-institutional environment for residents rather than with the facilities provided for the staff. The new tool for assessing building design has potential applications in further research and for care providers

    Guidelines for fabrication of hybrid microcircuits

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    Document is summary of approaches that may be taken in designing hybrid microcircuits similar to those for aerospace application

    An Unsplit, Cell-Centered Godunov Method for Ideal MHD

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    We present a second-order Godunov algorithm for multidimensional, ideal MHD. Our algorithm is based on the unsplit formulation of Colella (J. Comput. Phys. vol. 87, 1990), with all of the primary dependent variables centered at the same location. To properly represent the divergence-free condition of the magnetic fields, we apply a discrete projection to the intermediate values of the field at cell faces, and apply a filter to the primary dependent variables at the end of each time step. We test the method against a suite of linear and nonlinear tests to ascertain accuracy and stability of the scheme under a variety of conditions. The test suite includes rotated planar linear waves, MHD shock tube problems, low-beta flux tubes, and a magnetized rotor problem. For all of these cases, we observe that the algorithm is second-order accurate for smooth solutions, converges to the correct weak solution for problems involving shocks, and exhibits no evidence of instability or loss of accuracy due to the possible presence of non-solenoidal fields.Comment: 37 Pages, 9 Figures, submitted to Journal of Computational Physic

    The Propagation and Survival of Interstellar Grains

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    In this paper we discuss the propagation of dust through the interstellar medium (ISM), and describe the destructive effects of stellar winds, jets, and supernova shock waves on interstellar dust. We review the probability that grains formed in stellar outflows or supernovae survive processing in and propagation through the ISM, and incorporate themselves relatively unprocessed into meteoritic bodies in the solar system. We show that very large (radii >= 5 micron) and very small grains (radii <= 100 Angstrom) with sizes similar to the pre-solar SiC and diamond grains extracted from meteorites, can survive the passage through 100\kms shock waves relatively unscathed. High velocity (>= 250 km/s) shocks destroy dust efficiently. However, a small (~10%) fraction of the stardust never encountered such fast shocks before incorporation into the solar system. All grains should therefore retain traces of their passage through interstellar shocks during their propagation through the ISM. The grain surfaces should show evidence of processing due to sputtering and pitting due to small grain cratering collisions on the micron-sized grains. This conclusion seems to be in conflict with the evidence from the large grains recovered from meteorites which seem to show little interstellar processing.Comment: 19 pages, 5 figures (.eps), LaTeX, to appear in "Astrophysical Implications of the Laboratory Study of Presolar Materials" AIP Conference Proceedings, 1997 T.J. Bernatowicz and E. Zinner (eds.
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