Consumer perceptions of the safety, health and environmental impact of various scales and geographic origin of food supply chains

This was a nationwide survey of 500 consumers and their attitudes toward food safety, local foods, health benefits and willingness to pay for foods raised with environmental attributes

Improvements to parallel plate flow chambers to reduce reagent and cellular requirements

BACKGROUND: The parallel plate flow chamber has become a mainstay for examination of leukocytes under physiologic flow conditions. Several design modifications have occurred over the years, yet a comparison of these different designs has not been performed. In addition, the reagent requirements of many designs prohibit the study of rare leukocyte populations and require large amounts of reagents. RESULTS: In this study, we evaluate modifications to a newer parallel plate flow chamber design in comparison to the original parallel plate flow chamber described by Lawrence et al. We show that modifications in the chamber size, internal tubing diameters, injection valves, and a recirculation design may dramatically reduce the cellular and reagent requirements without altering measurements. CONCLUSIONS: These modifications are simple and easily implemented so that study of rare leukocyte subsets using scarce or expensive reagents can occur

Extending Grazing In Heifer Development Systems Decreases Cost Without Compromising Production

Three experiments compared heifer development systems. In Exp. 1, 299 heifers (253 ± 2 kg) from 3 yr were used to compare dry lot (DL) to grazing corn residue (CR) post weaning. Heifers in the DL consumed a common diet after weaning for 187 d until breeding. The CR heifers grazed for 145 d with a supplement (0.45 kg/d; 28% CP) and were then fed in the DL until breeding. In Exp. 2, 270 heifers (225 ± 2 kg) in 3 yr grazed Sandhills winter range (WR) or CR with a supplement (0.45 kg/d; 28% CP) post weaning. In Exp. 3, 180 heifers (262 ± 3 kg) in 2 yr grazed Eastern Nebraska WR or CR with a supplement (0.45 – 0.90 kg/d; 29% CP) post weaning. The CR heifers had lower (P \u3c 0.001) ADG before breeding compared to DL or WR heifers in Exp. 1 and 2, but WR and CR were similar (P = 0.66) in Exp. 3. The DL and WR heifers were heavier (P \u3c 0.003) than CR at breeding and pregnancy diagnosis in Exp. 1 and 2, but similar (P = 0.62) in Exp. 3. The percentage of heifers pubertal at breeding was greater (P \u3c 0.001) for DL than CR in Exp. 1, for WR than CR in yr 1 and 2 of Exp. 2 (P \u3c 0.01), but similar (P = 0.36) in Exp. 3. Pregnancy rate to AI was lower (P = 0.08) for CR than DL heifers in Exp. 1, but not different (P = 0.89) in Exp. 3. Final pregnancy rate was not affected (P ≥ 0.27) in Exp. 1, 2 or 3. In Exp. 2,, yr 2, CR heifers required (P = 0.01) more calving assistance than WR. Milk production of WR heifers was greater (P = 0.04) than CR in Exp. 3. Calf weaning BW, two-year old AI (Exp. 1 and 3) and final pregnancy rates (Exp. 1, 2 and 3) were not different (P \u3e 0.10). Development grazing CR reduced cost by $45/pregnancy compared to DL, but cost of WR was similar to CR. Development grazing CR reduces ADG before breeding without sacrificing final pregnancy rate. Development grazing WR increases milk production, but does not increase weaning BW. Grazing CR during heifer development reduces cost compared to DL. Grazing CR or WR is suitable for heifer development at similar cost

A model for reaction-assisted polymer dissolution in LIGA.

A new chemically-oriented mathematical model for the development step of the LIGA process is presented. The key assumption is that the developer can react with the polymeric resist material in order to increase the solubility of the latter, thereby partially overcoming the need to reduce the polymer size. The ease with which this reaction takes place is assumed to be determined by the number of side chain scissions that occur during the x-ray exposure phase of the process. The dynamics of the dissolution process are simulated by solving the reaction-diffusion equations for this three-component, two-phase system, the three species being the unreacted and reacted polymers and the solvent. The mass fluxes are described by the multicomponent diffusion (Stefan-Maxwell) equations, and the chemical potentials are assumed to be given by the Flory-Huggins theory. Sample calculations are used to determine the dependence of the dissolution rate on key system parameters such as the reaction rate constant, polymer size, solid-phase diffusivity, and Flory-Huggins interaction parameters. A simple photochemistry model is used to relate the reaction rate constant and the polymer size to the absorbed x-ray dose. The resulting formula for the dissolution rate as a function of dose and temperature is ?t to an extensive experimental data base in order to evaluate a set of unknown global parameters. The results suggest that reaction-assisted dissolution is very important at low doses and low temperatures, the solubility of the unreacted polymer being too small for it to be dissolved at an appreciable rate. However, at high doses or at higher temperatures, the solubility is such that the reaction is no longer needed, and dissolution can take place via the conventional route. These results provide an explanation for the observed dependences of both the dissolution rate and its activation energy on the absorbed dose

Implementation of an Adaptive Controller System from Concept to Flight Test

The National Aeronautics and Space Administration Dryden Flight Research Center (Edwards, California) is conducting ongoing flight research using adaptive controller algorithms. A highly modified McDonnell-Douglas NF-15B airplane called the F-15 Intelligent Flight Control System (IFCS) was used for these algorithms. This airplane has been modified by the addition of canards and by changing the flight control systems to interface a single-string research controller processor for neural network algorithms. Research goals included demonstration of revolutionary control approaches that can efficiently optimize aircraft performance for both normal and failure conditions, and to advance neural-network-based flight control technology for new aerospace systems designs. Before the NF-15B IFCS airplane was certified for flight test, however, certain processes needed to be completed. This paper presents an overview of these processes, including a description of the initial adaptive controller concepts followed by a discussion of modeling formulation and performance testing. Upon design finalization, the next steps are: integration with the system interfaces, verification of the software, validation of the hardware to the requirements, design of failure detection, development of safety limiters to minimize the effect of erroneous neural network commands, and creation of flight test control room displays to maximize human situational awareness

Analytic solutions of the Rolie Poly model in time-dependent shear

We consider shear flows that comprise of step changes in the shear rate. For these flows, we derive analytic solutions of the Rolie-Poly constitutive equation. Our method involves piecing together solutions for constant rate shear in a variety of flow rate regimes. We obtain solutions for interrupted shear, recoverable strain and non-linear relaxation following cessation of flow. Whenever strong flow is present we neglect reptation, as other mechanisms dominate and for interrupted shear our solution is approximate as we neglect convective constraint release. Our analytic solutions provide new insight in several ways. These include revealing the mechanism of some experimental features of these flows; suggesting a method to extract the polymer contribution to the normal stress in the velocity gradient direction (σyy) from shear stress measurements alone; and a method to isolate the influence of convective constraint release (CCR) from damping function measurements. We also run complementary GLaMM model calculations to verify that insight from our analytic approach translates to this more detailed model