The Conservation Reserve Program, Off-Farm Work, and Farm Household Technical Efficiencies

Using data from a national survey of farm households in the United States, this paper examines the effects of farm households’ decisions to participate in the Conservation Reserve Program (CRP) and to work off the farm on the technical efficiency of farm household production. After controlling for the self selection bias in estimating the multiple output-oriented distance functions, results show that operators’ decisions to work off the farm (both separately and combined with participation in CRP) lead to higher technical efficiencies for farm household production— implying improvements in the resource allocation between farm and other productive activities by farm households. The technical efficiencies of household production of those farm households participating only in the CRP are lower.Conservation Reserve Program, off-farm work, household technical efficiency, Agribusiness, Agricultural Finance, Farm Management,

Are Farmers' Decisions to Work off the Farm and Participate in the Conservation Reserve Program Independent, Joint or Sequential?

There is statistical evidence that decisions to participate in CRP and work off-farm are made simultaneously. Characteristics of households, farm operations other farm programs, and the local economies affect both decisions; some factors affect only one. Policy changes that affect one decision may affect another directly and/or indirectly.CRP, Off-farm labor, Choice Structure, Farm Management,

Does Participation in the Conservation Reserve Program and/or Off-Farm Work Affect the Level and Distribution of Farm Household Income?

Since both release resources from agricultural production, it is not surprising that decisions to work off the farm and to participate in the U. S. Conservation Reserve Program (CRP) are correlated. By incorporating these decisions into a heteroskedastic specification of a farm household income function, we identify their effects on mean income, as well as on the variability in income for groups of farm households participating in combinations of these activities. Our results indicate participation in CRP and off-farm work by the operator and the spouse increase farm household income, but these choices also decrease the variability in household income among participant households relative to that of other farm households with otherwise similar characteristics.Conservation Reserve Program, farm household income, income distribution, off-farm work, Agribusiness, Agricultural Finance, Farm Management,

Character decomposition of Potts model partition functions. II. Toroidal geometry

We extend our combinatorial approach of decomposing the partition function of the Potts model on finite two-dimensional lattices of size L x N to the case of toroidal boundary conditions. The elementary quantities in this decomposition are characters K\_{l,D} labelled by a number of bridges l=0,1,...,L and an irreducible representation D of the symmetric group S\_l. We develop an operational method of determining the amplitudes of the eigenvalues as well as some of their degeneracies.Comment: 27 pages, 4 figure

Observation of emission from chaotic lasing modes in deformed microspheres: displacement by the stable orbit modes

By combining detailed imaging measurements at different tilt angles with simulations of ray emission from prolate deformed lasing micro-droplets, we conclude that the probability density for the lasing modes in a three-dimensional dielectric microcavity must reside in the chaotic region of the ray phase space. In particular, maximum emission from such chaotic lasing modes is not from tangent rays emerging from the highest curvature part of the rim. The laser emission is observed and calculated to be non-tangent and displaced from the highest curvature due to the presence of stable orbits. In this Letter we present the first experimental evidence for this phenomenon of ``dynamical eclipsing''.Comment: 4 figure

The Effect of Water Storage on the Bending Properties of Esthetic, Fiber-Reinforced Composite Orthodontic Archwires

Objective: To study the effect of water storage on the bending properties of fiber-reinforced composite archwires and compare it to nickel-titanium (NiTi), stainless steel (SS), and beta-titanium archwires. Materials and Methods: Align A, B, and C and TorQ A and B composite wires from BioMers Products, 0.014-, 0.016, and 0.018-inch, and 0.019 × 0.025-inch NiTi, 0.016-inch SS, and 0.019 × 0.025-inch beta-titanium archwires were tested (n  =  10/type/size/condition). A 20-mm segment was cut from each end of the archwire; one end was then stored in water at 37°C for 30 days, while the other was stored dry. The segments were tested using three-point bending to a maximum deflection of 3.1 mm with force monitored during loading (activation) and unloading (deactivation). Statistical analysis was completed via two-way analysis of variance with wire and condition (dry and water-stored) as factors. Results: In terms of stiffness and force delivery during activation, in general: beta-titanium was \u3e TorQ B \u3e TorQ A \u3e 0.019 × 0.025-inch NiTi and 0.016-inch SS \u3e Align C \u3e 0.018-inch NiTi \u3e Align B \u3e 0.016-inch NiTi \u3e Align A \u3e 0.014-inch NiTi. Water exposure was detrimental to the larger translucent wires (Align B and C, TorQ A and B) because they were more likely to craze during bending, resulting in decreased forces applied at a given deflection. Align A and the alloy wires were not significantly (P\u3e .05) affected by water storage. Overall, the alloy wires possessed more consistent force values compared to the composite wires

Structural and electrostatic effects at the surfaces of size- and charge-selected aqueous nanodrops.

The effects of ion charge, polarity and size on the surface morphology of size-selected aqueous nanodrops containing a single ion and up to 550 water molecules are investigated with infrared photodissociation (IRPD) spectroscopy and theory. IRPD spectra of M(H2O) n where M = La3+, Ca2+, Na+, Li+, I-, SO42- and supporting molecular dynamics simulations indicate that strong interactions between multiply charged ions and water molecules can disrupt optimal hydrogen bonding (H-bonding) at the nanodrop surface. The IRPD spectra also reveal that "free" OH stretching frequencies of surface-bound water molecules are highly sensitive to the ion's identity and the OH bond's local H-bond environment. The measured frequency shifts are qualitatively reproduced by a computationally inexpensive point-charge model that shows the frequency shifts are consistent with a Stark shift from the ion's electric field. For multiply charged cations, pronounced Stark shifting is observed for clusters containing ∼100 or fewer water molecules. This is attributed to ion-induced solvent patterning that extends to the nanodrop surface, and serves as a spectroscopic signature for a cation's ability to influence the H-bond network of water located remotely from the ion. The Stark shifts measured for the larger nanodrops are extrapolated to infinite dilution to obtain the free OH stretching frequency of a surface-bound water molecule at the bulk air-water interface (3696.5-3701.0 cm-1), well within the relatively wide range of values obtained from SFG measurements. These cluster measurements also indicate that surface curvature effects can influence the free OH stretching frequency, and that even nanodrops without an ion have a surface potential that depends on cluster size