22,855 research outputs found
Agriculture
Applications of remote sensing in the areas of crop identification, range management, forest management and soil mapping are summarized
Transferring saturation, the finite cover property, and stability
Saturation is (mu,kappa)-transferable in T if and only if there is an
expansion T_1 of T with |T_1| = |T| such that if M is a mu-saturated model of
T_1 and |M| \geq kappa then the reduct M|L(T) is kappa-saturated. We
characterize theories which are superstable without the finite cover property
(f.c.p.), or without f.c.p. as, respectively those where saturation is
(aleph_0,lambda)-transferable or (kappa(T),lambda)-transferable for all lambda.
Further if for some mu \geq |T|, 2^mu > mu^+, stability is equivalent to: or
all mu \geq |T|, saturation is (\mu,2^mu)-transferable.Comment: This version replaces the 1995 submission: Characterization of the
finite cover property and stability. This version submitted by John T.
Baldwin. The paper has been accepted for the Journal of Symbolic Logi
Persistent Trade Effects of Large Exchage Rate Shocks
This paper presents a theoretical basis fcr the srgunent that large exchange rate shocks - such as the rise of the dollar from 1980 to 1985 - may shift historical relationships between exchange rates and trade flows. We begin with partial models in which large exchange rate fluctuations lead to entry or exit decisions that are not reversed when the currency returns to its previous level. When we develop a simple model of the feedback from "hysteresis" in trade to the exchange rate itself. Here we see that a large capital inflow, which leads to an initial appreciation, can result in a persistent reduction in the exchange rate consistent with trade balance.
Shifts in U.S. Relative Wages: The Role of Trade, Technology, and Factor Endowments
This paper investigates three hypotheses to account for the observed shifts in U.S. relative wages of less educated workers compared to more educated workers during the period from 1967 to 1992: (1) increased import competition, (2) changes in the relative supplies of labor of different educational levels, and (3) changes in technology. Our analysis relies on a basic relationship of the standard general equilibrium trade model that relates changes in product prices to factor price changes and factor shares, together with information about changes in the composition of output and trade, within-industry factor use, and factor supplies. For the period from 1967 to 1973, we conclude that the relative increase in the supply of well-educated labor was the dominant economic force that narrowed the wage gap among workers of different educational levels. In the 1980s and early 1990s, however, the wage gap between more educated and less educated workers widened sharply, despite the continued relative increase in the supply of workers with more education. We conclude that increased import competition cannot account for the observed increase in inequality among the major education groups, although it could have been a contributory cause of the decrease in the relative wages of the least educated workers. Instead, we find support for technical progress that is saving of less educated labor and that is more rapid in some manufacturing sectors intensively using highly educated labor as the dominant force in widening the wage gaps among college-educated workers, workers with a completed high school education, and workers with 1–11 years of schooling. Finally, we use the Deardorff-Staiger model, which allows changes in the factor content of trade to reveal the effects of trade on relative factor prices. Our empirical tests reinforce the conclusion that increased import competition between 1977 and 1987 was not the dominant force in widening the wage
Telemetry link for an automatic salmon migration monitor
The antenna and transmitter described in this report were designed for integration into the remote acoustic assessment system for detection of sockeye salmon in the Bristol Bay region of the Bering Sea. The assessment system configuration consists of an upward directed sonar buoy anchored 150 ft below the surface and attached by cable to a spar buoy tethered some 300 ft laterally. The spar buoy contains a telemetry transmitter, power supply, data processing electronics, an antenna and a beacon light
An initial analysis of the data from the Polar Orbiting Geophysical (POGS) Satellite
The Polar Orbiting Geophysical Satellite (POGS) was launched in 1990 to measure the geomagnetic field. POGS data from selected magnetically quiet days was chosen, quality checked and deleted where thought to be erroneous. A time and position correction was applied. The resulting data was fit to a degree 13 spherical harmonic model. Evaluation of the quality of the data indicates that it is sufficient for definition of the low degree (approximately less than 8) portion of the geomagnetic field. Further correction of the data time and position may improve this quality
The NASA Lewis large wind turbine program
The program is directed toward development of the technology for safe, reliable, environmentally acceptable large wind turbines that have the potential to generate a significant amount of electricity at costs competitive with conventional electric generation systems. In addition, these large wind turbines must be fully compatible with electric utility operations and interface requirements. Advances are made by gaining a better understanding of the system design drivers, improvements in the analytical design tools, verification of design methods with operating field data, and the incorporation of new technology and innovative designs. An overview of the program activities is presented and includes results from the first and second generation field machines (Mod-OA, -1, and -2), the design phase of the third generation wind turbine (Mod-5) and the advanced technology projects. Also included is the status of the Department of Interior WTS-4 machine
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