Economics, Control Theory, and the Phillips Machine

Can the same mathematical control laws that smooth out oscillations in the flight of an airplane also moderate economic cycles of boom and bust? Attempts to bring together the intellectual traditions of control engineering and economics go back at least as far as the hydraulic analog computer of A. W. H. Phillips, circa 1950. Today, economic policymakers remain committed to the ideal of controlling business cycles; it remains an open question whether tools from control theory might help to refine their strategies.

Organic barley producers' desired qualities for crop improvement

Barley fits well into many different organic farming systems. It can be grown as either a winter or spring annual crop in many temperate regions. Barley can be used for food, malting, or animal feed, providing growers with diverse marketing opportunities. Despite its advantages, many organic farmers in the USA have not adopted barley as a regular crop in their rotation. Researchers surveyed organic barley producers to discover what they considered to be the main obstacles to growing barley. The primary obstacles identified were limited markets and price. Breeding and development of high-quality barley suitable for organic systems and specialty markets may be a way to expand markets and secure a better price. Farmers identified yield as the most important agronomic trait of interest, but other traits such as nutritional quality were also highly ranked. Naked (hull-less) barley bred for multi-use quality is a possible alternative that allows organic farmers to sell into multiple markets. Most respondents expressed interest in the development of such varieties suitable for organic farming conditions. The researchers conducted follow-up interviews to obtain detailed information on how barley is used in organic farming systems, production practices, costs of production, and what traits farmers would like to see breeders focus on

Improving Barley for Organic Producers: What Do Organic Producers Want?

Researchers surveyed organic barley producers in order to find out how many acres they are growing, what varieties they grow, what markets they are growing barley for, whether they receive a price premium for organic barley, whether they are growing or would be interested in growing multi-use naked barley, what production challenges they face, and what traits they would like to see improved

YoeB toxin is activated during thermal stress.

Type II toxin-antitoxin (TA) modules are thought to mediate stress-responses by temporarily suppressing protein synthesis while cells redirect transcription to adapt to environmental change. Here, we show that YoeB, a ribosome-dependent mRNase toxin, is activated in Escherichia coli cells grown at elevated temperatures. YoeB activation is dependent on Lon protease, suggesting that thermal stress promotes increased degradation of the YefM antitoxin. Though YefM is efficiently degraded in response to Lon overproduction, we find that Lon antigen levels do not increase during heat shock, indicating that another mechanism accounts for temperature-induced YefM proteolysis. These observations suggest that YefM/YoeB functions in adaptation to temperature stress. However, this response is distinct from previously described models of TA function. First, YoeB mRNase activity is maintained over several hours of culture at 42°C, indicating that thermal activation is not transient. Moreover, heat-activated YoeB does not induce growth arrest nor does it suppress global protein synthesis. In fact, E. coli cells proliferate more rapidly at elevated temperatures and instantaneously accelerate their growth rate in response to acute heat shock. We propose that heat-activated YoeB may serve a quality control function, facilitating the recycling of stalled translation complexes through ribosome rescue pathways

User acceptance of intelligent avionics: A study of automatic-aided target recognition

User acceptance of new support systems typically was evaluated after the systems were specified, designed, and built. The current study attempts to assess user acceptance of an Automatic-Aided Target Recognition (ATR) system using an emulation of such a proposed system. The detection accuracy and false alarm level of the ATR system were varied systematically, and subjects rated the tactical value of systems exhibiting different performance levels. Both detection accuracy and false alarm level affected the subjects' ratings. The data from two experiments suggest a cut-off point in ATR performance below which the subjects saw little tactical value in the system. An ATR system seems to have obvious tactical value only if it functions at a correct detection rate of 0.7 or better with a false alarm level of 0.167 false alarms per square degree or fewer

Out-of-Autoclave Cure Composites

As the size of aerospace composite parts exceeds that of even the largest autoclaves, the development of new out-of-autoclave processes and materials is necessary to ensure quality and performance. Many out-of-autoclave prepreg systems can produce high-quality composites initially; however, due to long layup times, the resin advancement commonly causes high void content and variations in fiber volume. Applied Poleramic, Inc. (API), developed an aerospace-grade benzoxazine matrix composite prepreg material that offers more than a year out-time at ambient conditions and provides exceptionally low void content when out-of-autoclave cured. When compared with aerospace epoxy prepreg systems, API's innovation offers significant improvements in terms of out-time at ambient temperature and the corresponding tack retention. The carbon fiber composites developed with the optimized matrix technology have significantly better mechanical performance in terms of hot-wet retention and compression when compared with aerospace epoxy matrices. These composites also offer an excellent overall balance of properties. This matrix system imparts very low cure shrinkage, low coefficient of thermal expansion, and low density when compared with most aerospace epoxy prepreg materials

A Study of the Factors That Influence Consumer Attitudes Toward Beef Products Using the Conjoint Market Analysis Tool

This study utilizes an analysis technique commonly used in marketing, the conjoint analysis method, to examine the relative utilities of a set of beef steak characteristics considered by a national sample of 1,432 US consumers, as well as additional localized samples representing undergraduate students at a business college and in an animal science department. The analyses indicate that among all respondents, region of origin is by far the most important characteristic; this is followed by animal breed, traceability, animal feed, and beef quality. Alternatively, the cost of cut, farm ownership, the use (or nonuse) of growth promoters, and whether the product is guaranteed tender were the least important factors. Results for animal science undergraduates are similar to the aggregate results, except that these students emphasized beef quality at the expense of traceability and the nonuse of growth promoters. Business students also emphasized region of origin but then emphasized traceability and cost. The ideal steak for the national sample is from a locally produced, choice Angus fed a mixture of grain and grass that is traceable to the farm of origin. If the product was not produced locally, respondents indicated that their preferred production states are, in order from most to least preferred, Iowa, Texas, Nebraska, and Kansas.

THE EFFECT OF GREEN STRUCTURES ON HYDROLOGY IN URBAN AREAS OF AKRON, OHIO

Stormwater runoff is a major environmental concern in dense urban areas. Runoff in these areas contributes to flooding as well as water quality problems in the streams, lakes, and reservoirs downstream. The Cuyahoga River is the receiving waterbody for the City of Akron’s stormwater runoff. Currently, combined sewer overflow (CSO) from the city\u27s outdated sewer system is the overriding reason for poor water quality in the Cuyahoga River. Implementation of green infrastructure is one way to mitigate problems associated with stormwater runoff from urban areas. In this study, hydrologic modeling of the Little Cuyahoga watershed was conducted to determine how different levels of implementation of green infrastructure may cause different hydrological responses, such as a decrease in total stormwater runoff. In this study, the reduction in peak discharge at the outlet of the sub- watershed was evaluated by adjusting the curve number for each subbasin based on a level of implementation of green infrastructure. The HEC-HMS modeling simulation results concluded that moderately high levels of green infrastructure implementation would be required to reduce the outflow of the study area by a significant amount, solely based on the re-classification of land use for medium- and high-intensity urban areas. Although they are outside the scope of this study, there are added benefits to the implementation of green infrastructure, such as improvements in water quality. The cumulative benefits of both reduction in water volume and improvement of water quality make green infrastructure an excellent choice for the rehabilitation of a watershed. These improvements directly correlate to a significant reduction of construction and maintenance costs for hydrologic infrastructure of any major city