Index Catalog // ScholarsArchive@OSU

Improvements in pollutant monitoring: Optimizing silicone for co-deployment with polyethylene passive sampling devices

Creator:: O'Connell, Steven G., McCartney, Melissa A., Paulik, L. Blair, Allan, Sarah E., Tidwell, Lane G., Wilson, Glenn, and Anderson, Kim A.
Abstract:: Sequestering semi-polar compounds can be difficult with low-density polyethylene (LDPE), but those pollutants may be more efficiently absorbed using silicone. In this work, optimized methods for cleaning, infusing reference standards, and polymer extraction are reported along with field comparisons of several silicone materials for polycyclic aromatic hydrocarbons (PAHs) and pesticides....
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Full Text:: for co-deployment with polyethylene passive sampling devices Improvements in pollutant monitoring

Precision of the current methods to measure the alkenone proxy U₃₇ K’ and absolute alkenone abundance in sediments: results of an interlaboratory comparison study

Creator:: Rosell-Melé, A., Bard, E., Emeis, K.-C., Grimalt, J. O., Muller, P., Schneider, R., Bouloubassi, I., Epstein, B., Fahl, K., Fluegge, A., Freeman, K., Goñi, M., Güntner, U., Hartz, D., Hellebust, S., Herbert, T., Ikehara, M., Ishiwatari, R., Kawamura, K., Kenig, F., de Leeuw, J., Lehman, S., Mejanelle, L., Ohkouchi, N., Pancost, R. D., Pelejero, C., Prahl, Fredrick, Quinn, J., Rontani, J.-F., Rostek, F., Rullkötter, J., Sachs, J., Blanz, T., Sawada, K., Schulz-Bull, D., Sikes, E., Sonzogni, C., Ternois, Y., Versteegh, G., Volkman, J. K., and Wakeham, S.
Abstract:: Measurements of the U₃₇ K’ index and the absolute abundance of alkenones in marine sediments are increasingly used in paleoceanographic research as proxies of past sea surface temperature and haptophyte (mainly coccolith-bearing species) primary productivity, respectively. An important aspect of these studies is to be able to compare reliably data...
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Sampling bias in VGP longitudes

Creator:: Egbert, Gary D.
Abstract:: I derive probability densities for virtual geomagnetic pole( VGP) longitudes for a general statistical model of local magnetic field variations. I show that even for very simple statistically homogeneous models of secular variation, the distribution of VGP longitudes is peaked 90° away from the sampling longitude. Thus, when sites are...
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Full Text:: SAMPLING BIAS IN VGP LONGITUDES GEOPHYSICAL RESE•CH LETrERS

Behavioral Thresholds in Mixtures of Sand and Kaolinite Clay

Creator:: Simpson, D. C. and Evans, T. M.
Abstract:: Nearly all soils are comprised of mixtures of coarse and fine particles. Behavior under mechanical and thermal loading of soil is strongly influenced, and in some cases governed, by the ratio of coarse to fine particles. A better understanding of the fundamental behavior of soil mixtures will provide insight to...
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Full Text:: ) 377 Table 2 Observed behavioral thresholds 378 Threshold t*1 t*2 t*3 Approximate fines content

Hillslope run-off thresholds with shrink-swell clay soils

Creator:: Stewart, Ryan D., Abou Najm, Majdi R., Rupp, David E., Lane, John W., Uribe, Hamil C., Luis Arumí, José, and Selker, John S.
Abstract:: Irrigation experiments on 12 instrumented field plots were used to assess the impact of dynamic soil crack networks on infiltration and run-off. During applications of intensity similar to a heavy rainstorm, water was seen being preferentially delivered within the soil profile. However, run-off was not observed until soil water content...
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Full Text:: Hillslope run-off thresholds with shrink–swell clay

Threshold Management in A Coupled Economic-Ecological System

Creator:: Chen, Yong, Jayaprakash, Ciriyam, and Irwin, Elena
Abstract:: Economic analysis of optimal ecosystem management in the presence of a threshold has typically ignored the potential for induced behavioral responses. This paper contributes to the literature on non-convex ecosystem management by considering the implications of a particular behavioral response in a regional economy - that of amenity-led growth -...
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Full Text:: Threshold Management in A Coupled Economic-Ecological System

Sampling-based robotic information gathering algorithms

Creator:: Hollinger, Geoffrey A. and Sukhatme, Gaurav S.
Abstract:: We propose three sampling-based motion planning algorithms for generating informative mobile robot trajectories. The goal is to find a trajectory that maximizes an information quality metric (e.g. variance reduction, information gain, or mutual information) and also falls within a pre-specified budget constraint (e.g. fuel, energy, or time). Prior algorithms have...
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Full Text:: Sampling-based robotic information gathering algorithms

Sampling, feasibility, and priors in Bayesian estimation

Creator:: Chorin, Alexandre J., Lu, Fei, Miller, Robert N., Morzfeld, Matthias, and Tu, Xuemin
Abstract:: Importance sampling algorithms are discussed in detail, with an emphasis on implicit sampling, and applied to data assimilation via particle filters. Implicit sampling makes it possible to use the data to find high-probability samples at relatively low cost, making the assimilation more efficient. A new analysis of the feasibility of...
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Full Text:: DYNAMICAL SYSTEMS Volume 36, Number 8, August 2016 pp. 4227–4246 SAMPLING, FEASIBILITY, AND PRIORS IN DATA

Sinusoidal Clock Sampling for Multi-Gigahertz ADCs

Creator:: Bai, Rui, Wang, Jingguang, Xia, Lingli, Zhang, Feng, Yang, Zongren, Hu, Weiwu, and Chiang, Patrick
Abstract:: Current multi-gigahertz ADC performance is limited by the sampling clock timing jitter. This paper describes the effects of clock transition time on the spurious-free dynamic range (SFDR) of a CMOS T/H circuit. A signal-dependent nonlinearity model is first introduced that provides insight on the effect of finite clock transition time,...
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Full Text:: —Current multi-gigahertz ADC performance is limited by the sampling clock timing jitter. This paper

Flux Sampling Errors for Aircraft and Towers

Creator:: Mahrt, L.
Abstract:: Various errors and influences leading to differences between tower- and aircraft-measured fluxes are surveyed. This survey is motivated by reports in the literature that aircraft fluxes are sometimes smaller than tower-measured fluxes. Both tower and aircraft flux errors are larger with surface heterogeneity due to several independent effects. Surface heterogeneity...
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Full Text:: D O C E A N I C T E C H N O L O G Y q 1998 American Meteorological Society Flux Sampling Errors

Lichen communities and species indicate climate thresholds in southeast and south-central Alaska, USA

Creator:: Root, Heather T., McCune, Bruce, and Jovan, Sarah
Abstract:: Because of their unique physiology, lichen communities are highly sensitive to climatic conditions, making them ideal bioindicators for climate change. Southeast and south-central Alaska host diverse and abundant lichen communities and are faced with a more rapidly changing climate than many more southerly latitudes. We develop sensitive lichen-based indicators for...
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Effects of threshold retrievals on estimates of the aerosol indirect radiative forcing

Creator:: Matheson, Mark A., Coakley, James A., and Tahnk, William R.
Abstract:: Empirical estimates of the aerosol indirect radiative forcing often rely on threshold cloud retrievals applied to multispectral satellite imagery data. In such retrievals, pixels having radiances that surpass prescribed thresholds are assumed to be overcast even if they are only partially cloud covered. This assumption leads to cloud visible optical...
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Full Text:: gl025614 1..4 Effects of threshold retrievals on estimates of the

Fatigue threshold R-curves predict small crack fatigue behavior of bridging toughened materials

Creator:: Gallops, S., Fett, T., Ager, J. W., III, and Kruzic, J. J.
Abstract:: Small crack fatigue is a widely recognized problem in the fatigue of materials; however, there has been limited progress in developing methods for predicting small crack fatigue behavior. In this paper, small crack effects due to crack bridging are addressed. A fatigue threshold R-curve was measured for a 99.5% pure...
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Threshold levels of generalist predation determine consumer response to resource pulses

Creator:: Levi, Taal, Kilpatrick, A. Marm, Barfield, Michael, Holt, Robert D., Mangel, Marc, and Wilmers, Christopher C.
Abstract:: Many ecological systems are characterized by brief periods of increased resource availability called resource pulses. Empirical studies suggest that some populations of primary consumers grow rapidly in response to resource pulses, but others instead remain at low abundance despite increases in resource availability. Previous theory suggests that the lack of...
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Full Text:: Threshold levels of generalist predation determine consumer

Human hunting mortality threshold rules for extinction in mammals (and fish)

Creator:: Charnov, Eric L. and Zuo, Wenyun
Abstract:: Question: Are there general life-history rules for exploitation-caused extinction of mammal populations? Mathematical methods: A population of size N faced with the added mortality of human exploitation will deterministically go extinct if its per-capita birth rate can no longer match its per-capita mortality rate as N approaches zero. We develop...
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Full Text:: eel 22496 Human hunting mortality threshold rules for

Use of change-point detection for friction–velocity threshold evaluation in eddy-covariance studies

Creator:: Barr, A. G., Richardson, A. D., Hollinger, D. Y., Papale, D., Arain, M. A., Black, T. A., Bohrer, G., Dragoni, D., Fischer, M. L., Gu, L., Law, B. E., Margolis, H. A., McCaughey, J. H., Munger, J. W., Oechel, W., and Schaeffer, K.
Abstract:: The eddy-covariance method often underestimates fluxes under stable, low-wind conditions at night when turbulence is not well developed. The most common approach to resolve the problem of nighttime flux underestimation is to identify and remove the deficit periods using friction-velocity (u*) threshold filters (u*[superscript Th]). This study modifies an accepted...
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Full Text:: of change-point detection for friction–velocity threshold evaluation in eddy-covariance studies U e

Mowing Wyoming Big Sagebrush Communities With Degraded Herbaceous Understories: Has a Threshold Been Crossed?

Creator:: Davies, Kirk W., Bates, Jonathan D., and Nafus, Aleta M.
Abstract:: Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis [Beetle & A. Young] S.L. Welsh) plant communities with degraded native herbaceous understories occupy vast expanses of the western United States. Restoring the native herbaceous understory in these communities is needed to provide higher-quality wildlife habitat, decrease the risk of exotic plant invasion,...
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Full Text:: a Threshold Been Crossed? Kirk W. Davies,1 Jonathan D. Bates,1 and Aleta M. Nafus2 Authors are

Global vegetation monitoring: towards a sustainable technobiosphere

Creator:: Turner, David P.
Abstract:: The concept of sustainable resource management can be applied at multiple scales. Monitoring is an essential component of sustainable natural resource management schemes, and as we begin to confront the need to manage natural resources at the global scale, the importance of monitoring at the global scale is also growing....
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Full Text:: . 1999. A global terres- trial monitoring network integrating tower fluxes, flask sampling, ecosystem

Achieving operational hydrologic monitoring of mosquitoborne disease

Creator:: Shaman, Jeffrey and Day, Jonathan F.
Abstract:: Mosquitoes and mosquitoborne disease transmission are sensitive to hydrologic variability. If local hydrologic conditions can be monitored or modeled at the scales at which these conditions affect the population dynamics of vector mosquitoes and the diseases they transmit, a means for monitoring or modeling mosquito populations and mosquitoborne disease transmission...
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Full Text:: mosquitoes and the diseases they transmit, a means for monitoring or modeling mosquito populations and mos

Virtual constellations for global terrestrial monitoring

Creator:: Wulder, Michael A., Hilker, Thomas, White, Joanne C., Coops, Nicholas C., Masek, Jeffrey G., Pflugmacher, Dirk, and Crevier, Yves
Abstract:: Free and open access to satellite imagery and value-added data products have revolutionized the role of remote sensing in Earth system science. Nonetheless, rapid changes in the global environment pose challenges to the science community that are increasingly difficult to address using data from single satellite sensors or platforms due...
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Full Text:: monitoring Virtual constellations for global terrestrial monitoring Wulder, M. A., Hilker, T., White, J. C

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