1946 Fertilizer Recommendations for Field Crops, Permanent Pastures and Hay Fields

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An Embedded Rule-Based Diagnostic Expert System in Ada

Ada is becoming an increasingly popular programming language for large Government-funded software projects. Ada with it portability, transportability, and maintainability lends itself well to today's complex programming environment. In addition, expert systems have also assumed a growing role in providing human-like reasoning capability expertise for computer systems. The integration is discussed of expert system technology with Ada programming language, especially a rule-based expert system using an ART-Ada (Automated Reasoning Tool for Ada) system shell. NASA Lewis was chosen as a beta test site for ART-Ada. The test was conducted by implementing the existing Autonomous Power EXpert System (APEX), a Lisp-based power expert system, in ART-Ada. Three components, the rule-based expert systems, a graphics user interface, and communications software make up SMART-Ada (Systems fault Management with ART-Ada). The rules were written in the ART-Ada development environment and converted to Ada source code. The graphics interface was developed with the Transportable Application Environment (TAE) Plus, which generates Ada source code to control graphics images. SMART-Ada communicates with a remote host to obtain either simulated or real data. The Ada source code generated with ART-Ada, TAE Plus, and communications code was incorporated into an Ada expert system that reads the data from a power distribution test bed, applies the rule to determine a fault, if one exists, and graphically displays it on the screen. The main objective, to conduct a beta test on the ART-Ada rule-based expert system shell, was achieved. The system is operational. New Ada tools will assist in future successful projects. ART-Ada is one such tool and is a viable alternative to the straight Ada code when an application requires a rule-based or knowledge-based approach

Experimental Investigation of a Constant-Velocity Traveling Magnetic Wave Plasma Engine

The previously reported traveling magnetic wave plasma engine has been redesigned to reduce the high heat loss to the tube walls downstream of the last magnetic-field coil. The present configuration uses a 3-inch-diameter pyrex tube flared out to a 6-inch diameter immediately downstream of the last magnetic-field coil. This configuration has been studied to determine the effects of flared-tube geometry, molecular weight of the propellant, engine length, and use of a ferrite core on the engine performance. Argon and xenon gases were used as propellants. Two engine lengths were tested. One engine was nominally 1-magnetic-wavelength long (4 coils) and the other nominally 2 1/2-magnetic wavelengths long (10 coils). The magnetic wave speed for both of these lengths corresponds to a specific impulse of 4750 seconds. The maximum kinetic efficiency of the 4-coil engine was 10 percent at a specific impulse of 3200 seconds using argon gas and 22.5 percent at 4200 seconds using xenon gas as the propellant

Why Do Some Countries Produce So Much More Output per Worker than Others?

Output per worker varies enormously across countries. Why? On an accounting basis, our analysis shows that differences in physical capital and educational attainment can only partially explain the variation in output per worker we find a large amount of variation in the level of the Solow residual across countries. At a deeper level, we document that the differences in capital accumulation, productivity, and therefore output per worker are driven by differences in institutions and government policies, which we call social infrastructure. We treat social infrastructure as endogenous, determined historically by location and other factors captured in part by language.

The Value of Life and the Rise in Health Spending

Health care extends life. Over the past half century, Americans have spent a rising share of total economic resources on health and have enjoyed substantially longer lives as a result. Debate on health policy often focuses on limiting the growth of health spending. We investigate an issue central to this debate: can we understand the growth of health spending as the rational response to changing economic conditions---notably the growth of income per person? We estimate parameters of the technology that relates health spending to improved health, measured as increased longevity. We also estimate parameters of social preferences about longevity and the consumption of non-health goods and services. The story of rising health spending that emerges is that the diminishing marginal utility of non-health consumption combined with a rising value of life causes the nation to move up the marginal-cost schedule of life extension. The health share continues to grow as long as income grows. In projections based on our parameter estimates, the health share reaches 33 percent by the middle of the century.

The value of life and the rise in health spending

Health care extends life. Over the past half century, Americans spent a rising share of total economic resources on health and enjoyed substantially longer lives as a result. Debate on health policy often focuses on limiting the growth of health spending. We investigate an issue central to this debate: Is the growth of health spending the rational response to changing economic conditions - notably the growth of income per person? We develop a model based on standard economic assumptions and argue that this is indeed the case. Standard preferences - of the kind used widely in economics to study consumption, asset pricing, and labor supply - imply that health spending is a superior good with an income elasticity well above one. As people get richer and consumption rises, the marginal utility of consumption falls rapidly. Spending on health to extend life allows individuals to purchase additional periods of utility. The marginal utility of life extension does not decline. As a result, the optimal composition of total spending shifts toward health, and the health share grows along with income. This effect exists despite sharp diminishing returns in the technology of life extension. In projections based on the quantitative analysis of our model, the optimal health share of spending seems likely to exceed 30 percent by the middle of the century.

Perceptual-gestural (mis)mapping in serial short-term memory: The impact of talker variability

The mechanisms underlying the poorer serial recall of talker-variable lists (e.g., alternating female–male voices) as compared with single-voice lists were examined. We tested the novel hypothesis that this talker variability effect arises from the tendency for perceptual organization to partition the list into streams based on voice such that the representation of order maps poorly onto the formation of a gestural sequence-output plan assembled in support of the reproduction of the true temporal order of the items. In line with the hypothesis, (a) the presence of a spoken lead-in designed to further promote by-voice perceptual partitioning accentuates the effect (Experiments 1 and 2); (b) the impairment is larger the greater the acoustic coherence is between nonadjacent items: Alternating-voice lists are more poorly recalled than four-voice lists (Experiment 3); and (c) talker variability combines nonadditively with phonological similarity, consistent with the view that both variables disrupt sequence output planning (Experiment 4). The results support the view that serial short-term memory performance reflects the action of sequencing processes embodied within general-purpose perceptual input-processing and gestural output-planning systems

Taxes and Ownership Structure: Corporations, Partnerships and Royalty Trusts

This paper investigates the effect of taxes on the equilibrium ownership structure of productive assets. Ownership structure includes the traditional choice between debt and equity financing, but also the larger choice between corporate and partnership forms. A key feature of these alternative forms is that corporations are subject to taxation at both the corporate and investor levels, whereas partnerships are not. At the same time, depreciation and interest tax shields are taken at the corporate tax rate for corporate assets and at investors' tax rates for partnership assets. We find that assets endowed with excess non-interest tax deductions are best held in partnership form by high tax bracket investors. Assets whose allowed deductions are low enough to generate a net tax liability in corporate formare best held as partnerships by low tax bracket investors. All other assets are held in the corporate sector and are financed in a manner consistent with Miller's(1977) capital structure equilibrium.We argue that our analysis illuminates the tax aspects of such transactionsas mergers and sales or spin-offs of corporate assets to partnerships and royalty trusts. We also show that our results afford a simple characterization of the lease or buy decision.