An Ex Post Evaluation of the Conservation Reserve, Federal Crop Insurance, and Other Government Programs: Program Participation and Soil Erosion

Recent research has questioned the extent to which government policies, including conservation and risk management programs, have influenced environmental indicators. The impacts of income-supporting and risk management programs on soil erosion are considered. An econometric model of the determinants of soil erosion, program participation, conservation effort, and input usage is estimated. While the Conservation Reserve Program has reduced erosion an average of 1.02 tons per acre from 1982 to 1992, approximately half of this reduction has been offset by increased erosion resulting from government programs other than federally subsidized crop insurance.Conservation Reserve Program, farm policy, soil erosion, Agricultural and Food Policy,

Avian embryonic development in hyperdynamic environments

Embryos which developed for 24 hours in the oviduct of hens maintained at 2 G and which were subsequently incubated at Earth gravity had a 14% reduction in hatchability. Increased mortality during the first 4 days, and an increase in embryonic abnormalities were of the types usually found during the first mortality peak (2-3 days). Embryos in eggs that were produced at Earth gravity and continued their development on the centrifuge at fields of 2 G or less did not appear to be greatly affected by the treatment. At 4 G, 91% of the embryos died, mostly on the first and second days of incubation. Abnormalities prominent in the centrifuged eggs include: (a) a failure of the primitive streak to develop; (b) interference with the development of the axial skeleton; (c) multiple hemorrhages, mostly petechial which is consistent with capillary fragility; and (d) retardation of embryo growth, possibly caused by an interference with gaseous diffusion, the result of an acceleration-induced increase in gas density in the centrifuging incubator

Charge exchange lifetimes for ions in the magnetosphere

Latest and best measurements of physical quantities involved in complete calculation of the charge exchange lifetime of mirroring magnetospheric ions are coalesced and summarized. It is critical that the charge exchange lifetimes for ions be known as accurately as possible in order to apply the charge exchange mechanism to ion phenomena within the earth's magnetosphere

Harvest-Time Protein Shocks and Price Adjustment in U.S. Wheat Markets

Dynamic relationships between three classes of wheat are investigated using threshold VAR models incorporating the effects of protein availability. Changes in the stock of protein are found to generate significant impulse responses in the price of hard spring red wheat and hard red winter wheat but not soft red wheat. These impulse responses to identical changes in protein stocks are larger when the absolute deviations of protein stocks from normal levels are large. Shocks to the prices of individual classes of wheat result in complex impulse responses in the prices of the other wheats. Notably, however, a shock to the price of hard red winter wheat appears to result in little or no impluse response in the price of hard spring wheat, though, importantly, the opposite is not true.Demand and Price Analysis,

Harvest-Time Protein Shocks and Price Adjustment in U.S. Wheat Markets

Dynamic relationships among three classes of wheat are investigated using threshold VAR models that incorporate the effects of protein availability. Changes in the stock of protein are found to generate significant responses in the prices of hard red spring wheat and hard red winter wheat, but not soft red wheat. The responses to identical changes in protein stocks are larger when the magnitudes of deviations of protein stocks from normal levels are large. Shocks to the prices of individual classes of wheat result in complex responses in the prices of the other wheat classes. Notably, however, a shock to the price of hard red winter wheat appears to result in little or no response in the price of hard spring wheat, though importantly, the opposite is not true.protein, thresholds, vector autoregressions, wheat prices, Crop Production/Industries,

Dependence of the charge exchange lifetimes on mirror latitude

The dependence of the charge exchange lifetimes on the mirror latitude for ions mirroring off the geomagnetic equator was re-computed using the improved hydrogen distribution models. The Chamberlain model was used to define the spatial distribution of the neutral hydrogen environment through which the ring current ions traverse. The resultant dependence of the charge exchange lifetime on mirror latitude is best fitted by the approximation that contains the charge exchange lifetime for equatorial particles

Improved throat inserts for ablative thrust chambers

Composite material development and structural design of improved throat inserts for ablative thrust chamber

Cosmid Cloning of Five \u3cem\u3eZymomonas trp\u3c/em\u3e Genes by Complementation of \u3cem\u3eEscherichia coli\u3c/em\u3e and \u3cem\u3ePseudomonas putida trp\u3c/em\u3e Mutants

A library of Zymomonas mobilis genomic DNA was constructed in the broad-host-range cosmid pLAFR1. The library was mobilized into a variety of Escherichia coli and Pseudomonas putida trp mutants by using the helper plasmid pRK2013. Five Z. mobilis trp genes were identified by the ability to complement the trp mutants. The trpF, trpB, and trpA genes were on one cosmid, while the trpD and trpC genes were on two separate cosmids. The organization of the Z. mobilis trp genes seems to be similar to the organization found in Rhizobium spp., Acinetobacter calcoaceticus, and Pseudomonas acidovorans. The trpF, trpB, and trpA genes appeared to be linked, but they were not closely associated with trpD or trpC genes