Diffusion on a solid surface: anomalous is normal

We present a numerical study of classical particles diffusing on a solid surface. The particles motion is modeled by an underdamped Langevin equation with ordinary thermal noise. The particle-surface interaction is described by a periodic or a random two-dimensional potential. The model leads to a rich variety of different transport regimes, some of which correspond to anomalous diffusion such as has recently been observed in experiments and Monte Carlo simulations. We show that this anomalous behavior is controlled by the friction coefficient and stress that it emerges naturally in a system described by ordinary canonical Maxwell-Boltzmann statistics.

From subdiffusion to superdiffusion of particles on solid surfaces

We present a numerical and partially analytical study of classical particles obeying a Langevin equation that describes diffusion on a surface modeled by a two-dimensional potential. The potential may be either periodic or random. Depending on the potential and the damping, we observe superdiffusion, large-step diffusion, diffusion, and subdiffusion. Superdiffusive behavior is associated with low damping and is in most cases transient, albeit often long. Subdiffusive behavior is associated with highly damped particles in random potentials. In some cases subdiffusive behavior persists over our entire simulation and may be characterized as metastable. In any case, we stress that this rich variety of behaviors emerges naturally from an ordinary Langevin equation for a system described by ordinary canonical Maxwell-Boltzmann statistics.

Audit report on the Wayne-Ringgold-Decatur County Solid Waste Management Commission for the year ended June 30, 2011

Audit report on the Wayne-Ringgold-Decatur County Solid Waste Management Commission for the year ended June 30, 2011

Cost-effective experimental design to support modeling of concentration-response functions

Modeling concentration-response function became extremely popular in ecotoxicology during the last decade. Indeed, modeling allows determining the total response pattern of a given substance. However, reliable modeling is consuming in term of data, which is in contradiction with the current trend in ecotoxicology, which aims to reduce, for cost and ethical reasons, the number of data produced during an experiment. It is therefore crucial to determine experimental design in a cost-effective manner. In this paper, we propose to use the theory of locally D-optimal designs to determine the set of concentrations to be tested so that the parameters of the concentration-response function can be estimated with high precision. We illustrated this approach by determining the locally D-optimal designs to estimate the toxicity of the herbicide dinoseb on daphnids and algae. The results show that the number of concentrations to be tested is often equal to the number of parameters and often related to the their meaning, i.e. they are located close to the parameters. Furthermore, the results show that the locally D-optimal design often has the minimal number of support points and is not much sensitive to small changes in nominal values of the parameters. In order to reduce the experimental cost and the use of test organisms, especially in case of long-term studies, reliable nominal values may therefore be fixed based on prior knowledge and literature research instead of on preliminary experiments

Coarsening of solid-liquid mixtures in a random acceleration field

The effects of flow induced by a random acceleration field (g-jitter) are considered in two related situations that are of interest for microgravity fluid experiments: the random motion of isolated buoyant particles, and diffusion driven coarsening of a solid-liquid mixture. We start by analyzing in detail actual accelerometer data gathered during a recent microgravity mission, and obtain the values of the parameters defining a previously introduced stochastic model of this acceleration field. The diffusive motion of a single solid particle suspended in an incompressible fluid that is subjected to such random accelerations is considered, and mean squared velocities and effective diffusion coefficients are explicitly given. We next study the flow induced by an ensemble of such particles, and show the existence of a hydrodynamically induced attraction between pairs of particles at distances large compared with their radii, and repulsion at short distances. Finally, a mean field analysis is used to estimate the effect of g-jitter on diffusion controlled coarsening of a solid-liquid mixture. Corrections to classical coarsening rates due to the induced fluid motion are calculated, and estimates are given for coarsening of Sn-rich particles in a Sn-Pb eutectic fluid, an experiment to be conducted in microgravity in the near future.

Audit report on the Pocahontas County Solid Waste Commission for the year ended June 30, 2011

Audit report on the Pocahontas County Solid Waste Commission for the year ended June 30, 2011

Decision support systems in wood procurement. A Review

Summary

Proposed gravitational wave observatory based on solid elastic spheres

Spherical gravitational wave (GW) detectors offer a wealth of so far unexplored possibilities to detect gravitational radiation. We find that a sphere can be used as a powerful testbed for any metric theory of gravity, not only general relativity as considered so far, by making use of a deconvolution procedure for all the electric components of the Riemann tensor. We also find that the spheres cross section is large at two frequencies, and advantageous at higher frequencies in the sense that a single antenna constitutes a real xylophone in its own. Proposed GW networks will greatly benefit from this. The main features of a two large sphere observatory are reported.

Audit report on the Delaware County Solid Waste Disposal Commission for the year ended June 30, 2011

Audit report on the Delaware County Solid Waste Disposal Commission for the year ended June 30, 2011

Prevalence of patients' difficulties in swallowing solid oral dosage forms

Introduction Swallowing difficulties, or dysphagia, can occur in anyage group, although it is most common among elderly people. It canaffect patients' ability to take solid oral dosage forms, thus compromisingmedication adherence. Although literature is poor, availabledata show that prevalence in the general population ranges from 25 to60%. Prevalence in community pharmacies needs to be explored.Materials & Methods Community pharmacies were recruited from arandom selection in three Swiss states: Basel-Stadt (BS), Basel-Landschaft (BL) and Lausanne (LA). Patients' ability to swallowsolid oral medications was enquired with a semi-structured interview;the interviewer spent 4 h in each included pharmacy. Each consecutivepatient (18 years and older) entering the pharmacy with aprescription for at least 3 different solid oral forms was enrolled.Study was approved by the Lausanne ethics committee.Results Sixty pharmacies took part in the study (20 in BS, 10 in BL,30 in LA) between March and May 2010. Patient inclusion rate was77.8% (410/527). Prevalence of swallowing disorders was 22.4% (92/410). Patients with swallowing disorders were older (mean age: 67.5± 16 years vs. 63.0 ± 14 years, range 19-96; p = 0.03) and moreoften women (69.6% vs. 59.1%; Chi2 = 3.3, p = 0.04) than patientswithout swallowing disorders. They had on average 4.6 ± 2.7 drugswith a mean number of 5.5 ± 3.3 tablets or capsules to take daily,which didn't differ from the number of drugs taken by patientswithout swallowing difficulties (4.9 ± 2.5 drugs and 5.9 ± 3.5 tablets;n.s.). The difficulty was mainly related to the big size (63%) orthe quality of pill coating (rough, sticky, 14%). Twenty-one patients(37.5%) stated that their swallowing disorders resulted in nonadherence, rated as rarely (12 patients), sometimes (6 patients), veryoften (1 patient) or always (2 patients). According to patients, nopharmacist and only 2 physicians enquired about patients' swallowingissue.Discussion & Conclusion Swallowing difficulties are frequent amongpatients in community pharmacies in Switzerland with an estimatedprevalence of 22%. The problem resulted in non adherence or partialadherence in at least 35% of these patients. However, pharmacists andphysicians did not routinely inquire about the disorder. Guidelinesshould be developed for promoting systematic approaches of patientsin community pharmacies.

Audit report on the Crawford County Area Solid Waste Agency Commission for the year ended June 30, 2011

Audit report on the Crawford County Area Solid Waste Agency Commission for the year ended June 30, 2011

Statewide Economic Impacts of Disaster-Related Payments to Support Household and Private and Public Sector Recovery in Iowa, January 2010

There have been a multitude of programs providing assistance to the state of Iowa in the past 18 months. Springtime 2008 disasters resulted in tornado damage and widespread flood damage to large fractions of the state. In consequence, there was a very large flow of federal and state resources dedicated to assisting community and statewide recovery efforts. The nation was in recession as well and continued to be in recession through much of 2009. A sizeable amount of assistance found its way to Iowa under the American Recovery and Reinvestment Act of 2009 in the forms of infrastructure stimulus spending, income supports and other safety net spending for households, and stabilization assistance for essential public services like education. On top of that, the state of Iowa authorized the I Jobs program as an additional infrastructure development program, and as a jobs stimulus program. The total amount of spending for all types of programs, disaster or economic recovery related, is perhaps as high as $7.5 billion over the next few years.