The 1996 Federal Agriculture Improvement and Reform Act: Correcting a Distortion?

This study makes use of farm-level data from the Agricultural Census to evaluate the effects of the 1996 Federal Agriculture Improvement and Reform (FAIR) Act, which intended to "decouple" commodity payments from production decisions. Prior to this Act, agricultural support payments were linked to production decisions via prices and a complex set of restrictions that acted to control the supply of agricultural commodities. We compare farm-level 1992-to-1997 changes in commodity crop plantings of farms that participated in government programs with farms that did not participate. We find that the growth rate of program-crop acreage of non-participants was 19 percentage points below that of participants. This estimated difference remains unchanged after we account for unobserved effects relating to farm size, type, location, and interactions of these factors using over 1900 fixed-effects variables. These results may imply that program participation rules associated with pre-1996 programs effectively acted to limit program acreage in 1992. An alternative explanation is that payments associated with decoupled programs instituted with the 1996 Act were in fact distortionary and induced farmers to produce more than they would have without the payments. Additional research would be needed to test these competing theories.Agricultural and Food Policy,

Rotorcraft handling-qualities design criteria development

Joint NASA/Army efforts at the Ames Research Center to develop rotorcraft handling-qualities design criteria began in earnest in 1975. Notable results were the UH-1H VSTOLAND variable stability helicopter, the VFA-2 camera-and-terrain-board simulator visual system, and the generic helicopter real-time mathematical model, ARMCOP. An initial series of handling-qualities studies was conducted to assess the effects of rotor design parameters, interaxis coupling, and various levels of stability and control augmentation. The ability to conduct in-flight handling-qualities research was enhanced by the development of the NASA/Army CH-47 variable-stability helicopter. Research programs conducted using this vehicle include vertical-response investigations, hover augmentation systems, and the effects of control-force characteristics. The handling-qualities data base was judged to be sufficient to allow an update of the military helicopter handling-qualities specification, MIL-H-8501. These efforts, including not only the in-house experimental work but also contracted research and collaborative programs performed under the auspices of various international agreements. The report concludes by reviewing the topics that are currently most in need of work, and the plans for addressing these topics

Exact Polynomial Eigenmodes for Homogeneous Spherical 3-Manifolds

Observational data hints at a finite universe, with spherical manifolds such as the Poincare dodecahedral space tentatively providing the best fit. Simulating the physics of a model universe requires knowing the eigenmodes of the Laplace operator on the space. The present article provides explicit polynomial eigenmodes for all globally homogeneous 3-manifolds: the Poincare dodecahedral space S3/I*, the binary octahedral space S3/O*, the binary tetrahedral space S3/T*, the prism manifolds S3/D_m* and the lens spaces L(p,1).Comment: v3. Final published version. 27 pages, 1 figur

Do the clothes make the criminal? The influence of clothing match on identification accuracy in showups

Showups, a single suspect identification, are thought to be a more suggestive procedure than traditional lineups by the U.S. Supreme Court and social science researchers. Previous research typically finds that a clothing match in showup identifications increases false identifications. However, these experiments do not allow for a determination of whether this increase arises from a change in response bias, reduced discriminability, or both. In the present study, participants viewed a mock crime video and made a showup identification with either a clothing match or mismatch. Contrary to prior research, the best discriminability occurred when the guilty and innocent suspects wore clothing that matched the clothing worn during the crime. A clothing match also resulted in a more liberal response bias. The results are consistent with the principle of encoding specificity and the outshining hypothesis, as instantiated in the item, context, ensemble theory. Practical implications are discussed

Bosons in cigar-shape traps: Thomas-Fermi regime, Tonks-Girardeau regime, and between

We present a quantitative analysis of the experimental accessibility of the Tonks-Girardeau gas in the current day experiments with cigar-trapped alkalis. For this purpose we derive, using a Bethe anzats generated local equation of state, a set of hydrostatic equations describing one-dimensional delta-interacting Bose gases trapped in a harmonic potential. The resulting solutions cover the_entire range_ of atomic densities.Comment: 4 pages, 4 figure

Propagation of Bose-Einstein condensates in a magnetic waveguide

Gaseous Bose-Einstein condensates of 2-3 million atoms were loaded into a microfabricated magnetic trap using optical tweezers. Subsequently, the condensates were released into a magnetic waveguide and propagated 12 mm. Single-mode propagation was observed along homogeneous segments of the waveguide. Inhomogeneities in the guiding potential arose from geometric deformations of the microfabricated wires and caused strong transverse excitations. Such deformations may restrict the waveguide physics that can be explored with propagating condensates.Comment: 5 pages, 4 figure

Ground state properties of a one-dimensional condensate of hard core bosons in a harmonic trap

The exact N-particle ground state wave function for a one-dimensional condensate of hard core bosons in a harmonic trap is employed to obtain accurate numerical results for the one-particle density matrix, occupation number distribution of the natural orbitals, and momentum distribution. Our results show that the occupation of the lowest orbital varies as N^{0.59}, in contrast to N^{0.5} for a spatially uniform system, and N for a true BEC.Comment: 10 pages, 6 figures, submitted to Phys. Rev.