Short-run monetary growth fluctuations and real economic activity: some implications for monetary targeting

Monetary policy ; Demand for money

Currency substitution: a test of its importance

Money ; Monetary theory

Money, income and currency substitution: evidence from three countries

Monetary theory

The relative impact of monetary and fiscal actions on economic activity: a cross-country comparison

Monetary theory ; Fiscal policy

Rotorcraft In-Flight Simulation Research at NASA Ames Research Center: A Review of the 1980's and plans for the 1990's

A new flight research vehicle, the Rotorcraft-Aircrew System Concepts Airborne Laboratory (RASCAL), is being developed by the U.S. Army and NASA at ARC. The requirements for this new facility stem from a perception of rotorcraft system technology requirements for the next decade together with operational experience with the Boeing Vertol CH-47B research helicopter that was operated as an in-flight simulator at ARC during the past 10 years. Accordingly, both the principal design features of the CH-47B variable-stability system and the flight-control and cockpit-display programs that were conducted using this aircraft at ARC are reviewed. Another U.S Army helicopter, a Sikorsky UH-60A Black Hawk, was selected as the baseline vehicle for the RASCAL. The research programs that influence the design of the RASCAL are summarized, and the resultant requirements for the RASCAL research system are described. These research programs include investigations of advanced, integrated control concepts for achieving high levels of agility and maneuverability, and guidance technologies, employing computer/sensor-aiding, designed to assist the pilot during low-altitude flight in conditions of limited visibility. The approach to the development of the new facility is presented and selected plans for the preliminary design of the RASCAL are described

CPT- and B-Violation: The p-pbar Sector

The CPT symmetry of relativistic quantum field theory requires the total lifetimes of particles and antiparticles be equal. Detection of pbar lifetime shorter than tau_p > O(10^32) yr would signal breakdown of CPT invariance, in combination with B-violation. The best current limit on tau_pbar, inferred from cosmic ray measurements, is about one Myr, placing lower limits on CPT-violating scales that depend on the exact mechanism. Paths to CPT breakdown within and outside ordinary quantum mechanics are sketched. Many of the limiting CPT-violating scales in pbar decay lie within the weak-to-Planck range.Comment: 6 pages, LaTeX, .sty file included; based on contribution to CPT98 Conference; minor changes, accepted by Mod. Phys. Lett.

Effects of Stocking Density on Steer Performance and Carcass Characteristics in Bedded Hoop Barns

Use of bedded hoop barns for feeding cattle has grown in part due to increased regulations regarding open feedlot runoff. In 2010, ISU estimated almost 700 hoop barns in Iowa used for beef cattle and more than 80% were used for cattle feeding. Work in Iowa also has documented that cattle confined in a bedded hoop barn perform similarly to cattle fed in an open feedlot with shelter. The work was done with a stocking density of 50 sq ft per steer in the bedded hoop barn. A hoop barn is a more expensive facility system compared with open lot configurations. Fixed costs per steer (facilities) are partially determined by stocking density. The objective of this study was to determine the effects of increased stocking density on performance and carcass characteristics of steers fed in bedded hoop and bedded open front facilities. The trials were conducted in 2008 to 2011 at the ISU Armstrong Research Farm, Lewis, IA. The hoop barn was stocked with 40, 45 and 50 head per pen resulting in 50, 45 and 40 sq ft per steer, respectively. There was one stocking density per housing type per trial. The diet fed was 45.0% dry corn, 14.8% ground hay, 36.8% modified distillers grains and 3.4% supplement on an as-fed basis. The total diet was approximately 69% dry matter. Cattle growth rate (ADG), feed intake (DMI), feed efficiency (F/G) and mean mud score did not differ based on stocking density (P\u3e0.05). However, the cattle given more square feet numerically had greater feed intake and were more efficient (about 4-5%) than the more densely stocked cattle. This study may not have had enough replications to detect statistically significant differences. Also the mean carcass characteristics (fat cover, rib eye area, marbling score, quality grade and yield grade) did not differ by stocking density (P\u3e0.05). When comparing seasons only, steers fed in summer tended to have heavier market liveweight, heavier carcass weight, required less feed per liveweight and less marbling compared with steers fed in winter (P≤0.10). Also, the summer-fed steers grew faster and gained more liveweight than the winter-fed steers (P\u3c0.005). These results suggest that this study may not have reached the maximum stocking density for feeding beef cattle in a bedded hoop barn. In other words, market cattle can probably be stocked at less square footage per steer than the 40 sq ft per steer used in this study. Observations of farmers with hoop barns suggest that 37 or 35 sq ft per steer may be feasible. Several factors may affect stocking density including genetics or frame size of the cattle and may interact with season. Also, it should be noted that as the density of cattle increases, more management is required, i.e., more bedding, more bunk space, more waterer space and observing individual cattle for health issues becomes more difficult

Nutrient Retention Performance of a Crushed Limestone Floor Surface in a Bedded Hoop Barn with Confined Beef Cattle

Bedded confinement systems with partial concrete floors are increasingly being adopted by beef cattle feeders. The objective of this study was to determine the extent that manure nutrients moved into the soil below the geotextile fabric and packed limestone screenings floor of a bedded hoop barn used for beef cattle feeding at the ISU Armstrong Research and Demonstration Farm. Soil samples were taken (shallow and deep) before construction in 2004 and in 2008 after 7 groups of cattle were fed. Although single samples before and after animal feeding cannot provide conclusive evidence of moisture or nutrient migration, comparison of the sample results confirm a trend consistent with slow migration of manure nutrients into the soil profile. Phosphorus, calcium and magnesium did not show consistent or major trends with time. Organic matter showed a consistent increasing trend in both shallow and deep samples. Shallow sampling showed a marked increase only in nitrate-nitrogen, from 1.51 ppm to 11.47 ppm. These results are consistent with measurable, but very slow migration of moisture and nutrients into the soil profile. Additional soil tests over time and performance of an infiltration ring study may give more conclusive answers in the future