Miller, Richard E.; Hazard, John; Howes, Steven. 2001. Precision, accuracy, and efficiency of four tools for measuring soil bulk density or strength. Res. Pap. PNWRP-532. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 16 p. Monitoring soil compaction is time consuming. A desire for speed and lower costs, however, must be balanced with the appro...

Diffusive gradient in thin-films (DGT) technology was used to monitor bio-available metals and the tool was developed for risk-based pollution assessment and liability apportionment in the Witwatersrand Goldfields, South Africa, where there is widespread mine-related pollution. DGT technology is a passive sampling technique whereby metal species are selectively diffused from polluted water thro...

We have developed and evaluated a mathematical model to determine the effective sampling volumes (Veff) of PCBs and similar compounds captured using polyurethane foam passive air samplers (PUF-PAS). We account for the variability in wind speed, air temperature, and equilibrium partitioning over the course of the deployment of the samplers. The model, provided as an annotated Matlab script, pred...

Although several air sampling devices for identifying and enumerating airborne microorganisms are commercially available, each poses some limitations. The aim of this study was to evaluate air pollution fungi using three such samplers: SAS Super 100, Microbiological Air Sampler (MAS) 100, and Air IDEAL. Mycological air was taken from the cellars of a 17th-century church in Siemiatycze, Poland, ...

Many recent Markov chain Monte Carlo (MCMC) samplers leverage continuous dynamics to define a transition kernel that efficiently explores a target distribution. In tandem, a focus has been on devising scalable variants that subsample the data and use stochastic gradients in place of full-data gradients in the dynamic simulations. However, such stochastic gradient MCMC samplers have lagged behin...

Many Bayesian inference problems require exploring the posterior distribution of high-dimensional parameters that, in principle, can be described as functions. This work introduces a family of Markov chain Monte Carlo (MCMC) samplers that can adapt to the particular structure of a posterior distribution over functions. Two distinct lines of research intersect in the methods developed here. Firs...

Sediment and polyethylene sampler-based estimates of polychlorinated dibenzo-p-dioxin/dibenzofuran (PCDD/F) concentrations in Newark Bay, New Jersey (USA) benthic biota were compared. Biota concentrations based on sediment were estimated using an organic carbon (OC)-water partitioning model and an OC and black carbon (BC)-water dual model. Biota concentrations based on polyethylene were estimat...

This thesis describes work on two applications of probabilistic programming: the learning of probabilistic program code given specifications, in particular program code of one-dimensional samplers; and the facilitation of sequential Monte Carlo inference with help of data-driven proposals. The latter is presented with experimental results on a linear Gaussian model and a non-parametric dependen...

CONTENTS Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 808 Why Three-Dimensional Plume Delineation is Necessary . . . . . . . . . . . . . . . . . . . . . . . 812 Measurement of Vertical Hydraulic Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 814 One Time Sampling versus P...

Low-density polyethylene (PE) passive samplers containing performance reference compounds (PRCs) were deployed at multiple depths in two urban coastal marine locations to estimate dissolved concentrations of hydrophobic organic contaminants (HOCs), including dichlorodiphenyltrichloroethane (DDT) and its metabolites, polychlorinated biphenyl (PCB) congeners, and polybrominated flame retardants. ...