1,303 research outputs found

    Interannual Variation in Climate Contributes to Contingency in Post-Fire Restoration Outcomes in Seeded Sagebrush Steppe

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    Interannual variation, especially weather, is an often-cited reason for restoration “failures”; yet its importance is difficult to experimentally isolate across broad spatiotemporal extents, due to correlations between weather and site characteristics. We examined post-fire treatments within sagebrush-steppe ecosystems to ask: (1) Is weather following seeding efforts a primary reason why restoration outcomes depart from predictions? and (2) Does the management-relevance of weather differ across space and with time since treatment? Our analysis quantified range-wide patterns of sagebrush (Artemisia spp.) recovery, by integrating long-term records of restoration and annual vegetation cover estimates from satellite imagery following thousands of post-fire seeding treatments from 1984 to 2005. Across the Great Basin, sagebrush growth increased in wetter, cooler springs; however, the importance of spring weather varied with sites\u27 long-term climates, suggesting differing ecophysiological limitations across sagebrush\u27s range. Incorporation of spring weather, including from the “planting year,” improved predictions of sagebrush recovery, but these advances were small compared to contributions of time-invariant site characteristics. Given extreme weather conditions threatening this ecosystem, explicit consideration of weather could improve the allocation of management resources, such as by identifying areas requiring repeated treatments; but improved forecasts of shifting mean conditions with climate change may more significantly aid the prediction of sagebrush recovery

    Finite element analysis of hot-mix asphalt layer interface bonding

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    Doctor of PhilosophyDepartment of Civil EngineeringMustaque A. HossainTack coat is a thin layer of asphaltic material used to bind a newly-placed lift of hot-mix asphalt (HMA) pavement to a previously-placed lift or a new HMA overlay/inlay and existing pavement. The purpose of a tack coat is to ensure that a proper bond occurs so that traffic loads are carried by the entire HMA structure. Proper bonding exists when HMA layers act as a monolithic structure, transferring loads from one layer to the next. This depends on appropriate selection of tack coat material type and application rate, and is essential to prevent slippage failure and premature cracking in the wearing surface. This study focuses on development of a three-dimensional finite element (FE) model of HMA pavement structure in order to assess HMA interface bonding. The FE model was constructed using commercially available ABAQUS software to simulate an Accelerated Pavement Testing (APT) experiment conducted at the Civil Infrastructure Systems Laboratory (CISL) at Kansas State University. Mechanistic responses measured in the CISL experiment, such as localized longitudinal strain at the interface, were used to calibrate the FE model. Once calibrated, the model was used to predict mechanistic responses of the pavement structure by varying the tack coat property to reflect material characteristics of each application. The FE models successfully predicted longitudinal strains that corresponded to APT results

    Warfare, Demography & Anthropogenic Transformation at Angel Mounds State Historic Site

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    poster abstractRecent investigations by the Department of Anthropology (IU School of Liberal Arts) and the Glenn A. Black Laboratory of Archaeology (IU-Bloomington) at Angel Mounds have greatly enhanced our understanding of this Mississippian period (AD 1050-1450) village located on the Ohio River in southwestern Indiana. During this timeframe, the Ohio Valley and adjoining regions witnessed an evolution in social complexity with the emergence of small-scale polities, population aggregation in fortified towns, and associated earthwork construction. Angel Mounds was established, grew in prominence, and was eventually abandoned. However, until recently, absolute ages from the site were sparse and the chronology of the town’s settlement, growth and abandonment was poorly understood. Similarly, chronological models for earthwork and fortification construction were non-existent. Our research has revealed that Angel Mounds began as a ceremonial center between AD 1100 and 1300 with few occupants. The residential population at Angel Mounds grew precipitously after AD 1300. By AD 1400, we estimate that as many as 1,000 people lived at Angel Mounds. Concurrently, a series of fortifications were erected at the site to protect the inhabitants from neighboring polities. Meanwhile, earthworks on site were “capped” and abandoned soon thereafter, which may reflect the sociopolitical disintegration of Angel Mounds. Depending on the type of agricultural production and environmental change with the onset of the Little Ice Age, these patterns have important implications for settlement longevities, the historical ecology of land-use, and population estimates in the Eastern Woodlands of North America by AD 1500. With support from the Nation Science Foundation, the next three years of investigations at Angel Mounds will continue to focus on population dynamics, earthwork construction and use, anthropogenic transformation of the landscape, and environmental change during the Medieval Warm and Little Ice Age

    A national survey of clinical practice for the management of whiplash-associated disorders in UK emergency departments

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    Objective: To undertake a national survey to determine current practice for the management of whiplash injuries in UK emergency departments (ED). Methods: Postal questionnaire survey. 316 lead consultants from all UK ED with annual new attendances of over 50 000 people were asked to indicate the use of a range of treatments and the frequency with which these treatments were used. Samples of written advice were requested and content analysis was conducted and compared with survey responses. Results: The response rate was 79% (251/316). The intervention most frequently used was verbal advice to exercise, reported by 84% of respondents for most or all cases, and advice against the use of a collar (83%). Other treatments reported as being used frequently were written advice and anti-inflammatory medication. 106 consultants (42%) provided a sample of written materials. Reference to expected recovery and encouragement for early return to activities were included in less than 6%. Nearly 50% of written materials contained information on how to use a soft collar and 61% contained information on solicitors and pursuing a personal injury claim. There were important differences between reported verbal behaviours and written advice. Conclusion: Verbal advice is the primary method for managing whiplash injuries in ED and is usually supplemented by written advice. Within individual hospitals there is a lack of consistency between verbal and written advice. The promotion of personal injury claims is a common feature of written advice. Research is required to develop effective and consistent models of advice

    Drug-resistant Escherichia coli, Rural Idaho

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    Stool carriage of drug-resistant Escherichia coli in home-living residents of a rural community was examined. Carriage of nalidixic acid–resistant E. coli was associated with recent use of antimicrobial agents in the household. Household clustering of drug-resistant E. coli was observed. Most carriers of drug-resistant E. coli lacked conventional risk factors

    Modal Platonism and the problem of negativity.

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    The Platonic account of modality says, roughly, that truths about alien possibilities are grounded in uninstantiated universals. Recently, Ingram has raised a problem for this kind of view, which is that it apparently requires negative facts to play a truthmaking role. Ingram offers an alternative Platonic account which makes use of modal instantiation relations. In this paper, I highlight some of the costs of Ingram’s new account and argue that a more appealing version of Platonism—and modal theory in general—is one that is supplemented with an ontology of totality facts

    Detecting the Companions and Ellipsoidal Variations of RS CVn Primaries: II. omicron Draconis, a Candidate for Recent Low-Mass Companion Ingestion

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    To measure the stellar and orbital properties of the metal-poor RS CVn binary o Draconis (o Dra), we directly detect the companion using interferometric observations obtained with the Michigan InfraRed Combiner at Georgia State University's Center for High Angular Resolution Astronomy (CHARA) Array. The H-band flux ratio between the primary and secondary stars is the highest confirmed flux ratio (370 +/- 40) observed with long-baseline optical interferometry. These detections are combined with radial velocity data of both the primary and secondary stars, including new data obtained with the Tillinghast Reflector Echelle Spectrograph on the Tillinghast Reflector at the Fred Lawrence Whipple Observatory and the 2-m Tennessee State University Automated Spectroscopic Telescope at Fairborn Observatory. We determine an orbit from which we find model-independent masses and ages of the components (M_A = 1.35 +\- 0.05 M_Sun, M_B = 0.99 +\- 0.02 M_Sun, system age = 3.0 -\+ 0.5 Gyr). An average of a 23-year light curve of o Dra from the Tennessee State University Automated Photometric Telescope folded over the orbital period newly reveals eclipses and the quasi-sinusoidal signature of ellipsoidal variations. The modeled light curve for our system's stellar and orbital parameters confirm these ellipsoidal variations due to the primary star partially filling its Roche lobe potential, suggesting most of the photometric variations are not due to stellar activity (starspots). Measuring gravity darkening from the average light curve gives a best-fit of beta = 0.07 +\- 0.03, a value consistent with conventional theory for convective envelope stars. The primary star also exhibits an anomalously short rotation period, which, when taken with other system parameters, suggests the star likely engulfed a low-mass companion that had recently spun-up the star.Comment: 14 pages, 13 figures, Accepted to Ap
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