CONSUMER ACCEPTANCE OF IRRADIATED PRODUCE

Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,

CONSUMER ACCEPTANCE OF IRRADIATED FOOD PRODUCTS: AN APPLE MARKETING STUDY

This study was exploratory in nature, with emphasis on initial purchases and not repeat purchases or long-term loyalties to either irradiated or non-irradiated produce. The investigation involved the actual sale of irradiated and non-irradiated apples to consumers. Limited information about the process was provided, and apples were sold at roadside stands. Prices for the irradiated apples were varied while the price for the non-irradiated apples was held constant. Of these 228 West-Central Missouri shoppers, 101 (44%) bought no irradiated apples, 86 (38%) bought only irradiated apples, and 41 (18%) bought some of both types. Results of probit regressions indicated three significant independent variables. There was an inverse relationship between the price of irradiated apples and the probability of purchasing irradiated apples. There was a positive relationship between the purchasers' educational level and the probability of purchasing irradiated apples. Predicted probabilities for belonging to categories in probit models were computed. Depending on particular equation specification, correctly placed were approximately 70 percent of the purchasers of the two categories-bought only non-irradiated apples, or bought some of both irradiated and non-irradiated apples or only irradiated apples. This study suggests that consumers may be interested in food irradiation as a possible alternative or supplement to current preservation techniques.Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,

Using practice effects for targeted trials or sub-group analysis in Alzheimer\u27s disease: How practice effects predict change over time

OBJECTIVE: To describe the presence of practice effects in persons with Alzheimer disease (AD) or mild cognitive impairment (MCI) and to evaluate how practice effects affect cognitive progression and the outcome of clinical trials. METHODS: Using data from a meta-database consisting of 18 studies including participants from the Alzheimer disease Cooperative Study (ADCS) and the Alzheimer Disease Neuroimaging Initiative (ADNI) with ADAS-Cog11 as the primary outcome, we defined practice effects based on the improvement in the first two ADAS-Cog11 scores and then estimated the presence of practice effects and compared the cognitive progression between participants with and without practice effects. The robustness of practice effects was investigated using CDR SB, an outcome independent the definition itself. Furthermore, we evaluated how practice effects can affect sample size estimation. RESULTS: The overall percent of practice effects for AD participants was 39.0% and 53.3% for MCI participants. For AD studies, the mean change from baseline to 2 years was 12.8 points for the non-practice effects group vs 7.4 for the practice effects group; whereas for MCI studies, it was 4.1 for non-practice effects group vs 0.2 for the practice effects group. AD participants without practice effects progressed 0.9 points faster than those with practice effects over a period of 2 years in CDR-SB; whereas for MCI participants, the difference is 0.7 points. The sample sizes can be different by over 35% when estimated based on participants with/without practice effects. CONCLUSION: Practice effects were prevalent and robust in persons with AD or MCI and affected the cognitive progression and sample size estimation. Planning of future AD or MCI clinical trials should account for practice effects to avoid underpower or considers target trials or stratification analysis based on practice effects

Cement Paste, Mortar and Concrete Under Monotonic, Sustained and Cyclic Loading

The behavior of saturated specimens of cement paste and mortar under monotonic, sustained and cyclic loading, is compated to that of concrete at water - cement ratios of 0.5 and 0.7. Specimen age, at testing, ranges from 27 to 29 days. For monotonic loading, the behavior of each material is described in terms of peak stress, strain at peak stress, and initial modulus of elasticity. For sustained loading, the behavior is described in terms of creep strain as a function of stress - strength ratio and time under load. Mathematical relationships ate developed on the sustained load response to estimate the cumulative static creep for a cyclic test. Cyclic test results ate exatnined in terms of strain at 15 seconds, the difference between the strain at 15 seconds and the peak strain for a given cycle (cyclic strain), the estimated creep strain for a cyclic test (equivalent creep, based on sustained load test results), the difference between cyclic strain and equivalent creep (cyclic action strain), and the change in secant unloading modulus (a measute of material damage). The equivalent creep duting a cyclic test is used to distinguish between cyclic strain and cyclic action strain, which may include accelerated creep strain as well as strain related to tnicrocracking. Cyclic action strain is correlated with change in modulus of elasticity to determine the extent to which these strains ate the result of damage. Monotonic test results show that for the materials used in this study, at a given water - cement ratio, cement paste has a higher strength and strain capacity than do the corresponding mortat and concrete, while mortat and concrete have a higher initial stiffness than cement paste. Sitnilatly, mortat has a higher strength and strain capacity than the corresponding concrete, but has approximately the same initial stiffness. The sustained load test results show that over a four hour period, creep strain increases nonlinearly with increasing stress - strength ratio. At the same stress - strength ratio, total strain and creep strain accumulate more rapidly for cement paste than for mortar and more rapidly for mortar than for concrete. The cyclic test results show that for cyclic tests with a maximum stress - strength ratio greater than 0.6f', cyclically loaded cement paste, mortar and concrete exhibit larger strains than similar materials exposed to a sustained load equal to the mean cyclic stress. For the load regimes studied, maximum cyclic stress appears to have a much greater impact on the cyclic action strain and change in stiffness than the mean cyclic stress or the cyclic stress range. The overall damage, as measured by the cyclic action strain and change in secant unloading modulus, in mortar in concrete is similar, suggesting that the behavior of concrete under cyclic loading is dominated by its mortar constituent. Under monotonic, sustained and cyclic loading, the behavior of mortar more closely resembles that of concrete than it does cement paste

Ohio Livestock Waste Management Guide

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Stable carbon isotope signatures of ancient Maize agriculture at El Kinel, Guatemala

Abstract Stable C isotope studies of the soil organic matter (SOM) have delineated areas with histories of vegetation change from C3 forest to C4 maize (Zea mays L.) agriculture and back to the contemporary C3 forest. The objectives of this study were to: (1) determine if land around El Kinel, Guatemala possessed a vegetative history of shifts from C3 forest to C4 maize agriculture in the past, (2) determine if 10 years of contemporary maize production is sufficient time to deposit an isotopic signature of C4 plants in the root zone (top 40 cm), and (3) to examine the extractable phosphorus concentrations and δ13C in soils of important archaeological features that included a midden, a burial, and two ancient reservoirs (aguadas). The lack of a shift in δ13C greater than 3.5‰ in the top 40 cm of the contemporary maize field suggested that continual maize cultivation of more than ten years is required to create an isotopic signature for maize agriculture. Carbon isotopic evidence was found in soil profiles to confirm that long-term agriculture was practiced by ancient Maya farmers at El Kinel. The man-made aguadas did not show isotopic shifts greater than 2.3‰ in any part of the profile, indicating they were used for other purposes not associated with C4 plant growth. The relatively low P (−1) was found in soil at the same depth but at a distance of 30 cm from an ancient burial. The high P concentration (127 mg kg−1) found within millimeters of the bones implied that the P enrichment came from the remains but P remained fixed in the soil and did not migrate

Water resources development alternatives for the Mississippi Alluvial Plain in Eastern Arkansas

Effective management of the water resources of the Mississippi Alluvial Plain in eastern Arkansas involves understanding the nature of existing problems, estimating total water demands, predicting how much of the total demand can be provided by the underlying aquifer and available surface-water sources, and deducing how much water must come from alternate sources. Various Federal and State agencies have cooperatively provided hydrologic information for the area to evaluate water-resources development alternatives ensuring that (1) the use of water from the aquifer be maximized while maintaining a minimum of 20 feet of saturated thickness, (2) the use of surface water be maximized where it is currently available, and (3) alternate sources of water (surplus surface water) be identified for use in deficit areas. Water-resources development alternatives are being evaluated by using digital groundwater flow and optimization models. The optimization model is used to maximize withdrawals from the aquifer and from available surface-water sources, while maintaining a minimum saturated thickness in the aquifer. The validity of predictions in both the flow and optimization models depends on the accuracy of historic and projected water use. Optimization model by-products include estimates of unmet water-use demands and the location of surplus surface water that would be available for transport to and utilization in deficient areas

The elimination of surface cross-hatch from relaxed, limited-area Si1 – xGex buffer layers

The influence of lateral dimensions on the relaxation and surface topography of linearly graded Si1 – xGex buffer layers has been investigated. A dramatic change in the relaxation mechanism has been observed for depositions on Si mesa pillars of lateral dimensions 10 µm and below. Misfit dislocations are able to extend unhindered and terminate at the edges of the growth zone, yielding a surface free of cross-hatch. For lateral dimensions in excess of 10 µm orthogonal misfit interactions occur and relaxation is dominated by the modified Frank–Read (MFR) mechanism. The stress fields associated with the MFR dislocation pile-ups result in a pronounced cross-hatch topography

Evidence for quantum confinement in the photoluminescence of porous Si and SiGe

We have used anodization techniques to process porous surface regions in p-type Czochralski Si and in p-type Si0.85Ge0.15 epitaxial layers grown by molecular beam epitaxy. The SiGe layers were unrelaxed before processing. We have observed strong near-infrared and visible light emission from both systems. Analysis of the radiative and nonradiative recombination processes indicate that the emission is consistent with the decay of excitons localized in structures of one or zero dimensions