Water quality issues in the Illinois River watershed: A proposal for new voluntary incentives

Concerns about water quality degradation exist in Northwest Arkansas. The purpose of this study was to analyze the potential usefulness of U.S. conservation programs in addressing water quality concerns on farms in the Illinois River watershed as well as greater Washington County, Arkansas. It was hypothesized that neither the Environmental Quality Incentives Program (EQIP) nor the Conservation Security Program (CSP) in their current forms effectively assists farmers in meeting water-quality management goals. That hypothesis was tested by 1) examining agricultural characteristics of the watershed, 2) actual adoption of EQIP and CSP in Washington County and Arkansas, and, 3) identifying factors that influence program adoption. Results show that based on watershed and farmer characteristics, neither program can meet water quality goals for the region. EQIP adoption is hindered by high rejection rates of applications and farmer dissatisfaction with the program. CSP adoption is unlikely because it does not consider watersheds with degraded water quality and allowable best management practices (BMPs) do not include those related to waste management – precisely the practices most often used by these watershed farmers. Suggestions are offered to modify both EQIP and CSP and use them as a two-part plan to better serve the needs of farmers and improve both adoption rates of BMPs by farmers and water quality in the region

Magnetometry of random AC magnetic fields using a single Nitrogen-Vacancy center

We report on the use of a single NV center to probe fluctuating AC magnetic fields. Using engineered currents to induce random changes in the field amplitude and phase, we show that stochastic fluctuations reduce the NV center sensitivity and, in general, make the NV response field-dependent. We also introduce two modalities to determine the field spectral composition, unknown a priori in a practical application. One strategy capitalizes on the generation of AC-field-induced coherence 'revivals', while the other approach uses the time-tagged fluorescence intensity record from successive NV observations to reconstruct the AC field spectral density. These studies are relevant for magnetic sensing in scenarios where the field of interest has a non-trivial, stochastic behavior, such as sensing unpolarized nuclear spin ensembles at low static magnetic fields.Comment: 11 pages, 3 figure

Spacelab experiment computer study. Volume 2: Study elements and approach

For abstract, see volume 1 N77-13097

Content vs. context for multimedia semantics: the case of SenseCam image structuring

Much of the current work on determining multimedia semantics from multimedia artifacts is based around using either context, or using content. When leveraged thoroughly these can independently provide content description which is used in building content-based applications. However, there are few cases where multimedia semantics are determined based on an integrated analysis of content and context. In this keynote talk we present one such example system in which we use an integrated combination of the two to automatically structure large collections of images taken by a SenseCam, a device from Microsoft Research which passively records a person’s daily activities. This paper describes the post-processing we perform on SenseCam images in order to present a structured, organised visualisation of the highlights of each of the wearer’s days

Equilibrium binding energies from fluctuation theorems and force spectroscopy simulations

Brownian dynamics simulations are used to study the detachment of a particle from a substrate. Although the model is simple and generic, we attempt to map its energy, length and time scales onto a specific experimental system, namely a bead that is weakly bound to a cell and then removed by an optical tweezer. The external driving force arises from the combined optical tweezer and substrate potentials, and thermal fluctuations are taken into account by a Brownian force. The Jarzynski equality and Crooks' fluctuation theorem are applied to obtain the equilibrium free energy difference between the final and initial states. To this end, we sample non--equilibrium work trajectories for various tweezer pulling rates. We argue that this methodology should also be feasible experimentally for the envisioned system. Furthermore, we outline how the measurement of a whole free energy profile would allow the experimentalist to retrieve the unknown substrate potential by means of a suitable deconvolution. The influence of the pulling rate on the accuracy of the results is investigated, and umbrella sampling is used to obtain the equilibrium probability of particle escape for a variety of trap potentials.Comment: 21 pages, 11 figures, To appear in Soft Matte

Evaluation of registration, compression and classification algorithms. Volume 1: Results

The registration, compression, and classification algorithms were selected on the basis that such a group would include most of the different and commonly used approaches. The results of the investigation indicate clearcut, cost effective choices for registering, compressing, and classifying multispectral imagery

Evaluation of registration, compression, and classification algorithms. Volume 2: Documentation

There are no author-identified significant results in this report

Stability of nonuniform rotor blades in hover using a mixed formulation

A mixed formulation for calculating static equilibrium and stability eigenvalues of nonuniform rotor blades in hover is presented. The static equilibrium equations are nonlinear and are solved by an accurate and efficient collocation method. The linearized perturbation equations are solved by a one step, second order integration scheme. The numerical results correlate very well with published results from a nearly identical stability analysis based on a displacement formulation. Slight differences in the results are traced to terms in the equations that relate moments to derivatives of rotations. With the present ordering scheme, in which terms of the order of squares of rotations are neglected with respect to unity, it is not possible to achieve completely equivalent models based on mixed and displacement formulations. The one step methods reveal that a second order Taylor expansion is necessary to achieve good convergence for nonuniform rotating blades. Numerical results for a hypothetical nonuniform blade, including the nonlinear static equilibrium solution, were obtained with no more effort or computer time than that required for a uniform blade