6,943 research outputs found
Agricultural Policy as a Social Engineering Tool
This study uses logistic regression to estimate survey data on social engineering policies in the agricultural sector. The study finds that farm operators are unlikely to support a policy allowing countries to restrict trade to pursue domestic economic and social policy goals if the policies affect international trade. In particular the findings suggest that farm operators with annual gross sales including government payments between 999,999 are 80 percent less likely to indicate such a preference. Farm operators with advanced degrees, some college education and a high school diploma are also unlikely to indicate such a preference. In contrast farm operators who receive no income from farming or ranching and farm operators who receive a percentage of their family income from farming or ranching indicate that countries should be allowed to restrict trade to pursue domestic economic and social policy goals even if the policies affect international trade.Agricultural and Food Policy,
Power-law dependence of the angular momentum transition fields in few-electron quantum dots
We show that the critical magnetic fields at which a few-electron quantum dot
undergoes transitions between successive values of its angular momentum (M),
for large M values follow a very simple power-law dependence on the effective
inter-electron interaction strength. We obtain this power law analytically from
a quasi-classical treatment and demonstrate its nearly-universal validity by
comparison with the results of exact diagonalization.Comment: Uses RevTeX4, 6 figures included in the tex
Re-entrant pinning of Wigner molecules in a magnetic field due to a Coulomb impurity
Pinning of magnetic-field induced Wigner molecules (WMs) confined in
parabolic two-dimensional quantum dots by a charged defect is studied by an
exact diagonalization approach. We found a re-entrant pinning of the WMs as
function of the magnetic field, a magnetic field induced re-orientation of the
WMs and a qualitatively different pinning behaviour in the presence of a
positive and negative Coulomb impurity
THE ROLE OF FARM OWNERSHIP IN OFF-FARM WORK PARTICIPATION
A labor supply model is used to examine the relationship between farm ownership and operators' participation in the off-farm labor market for the Northeast region. The results indicate that ownership significantly influences operators' off-farm employment participation. In particular, part-owners significantly allocate labor services to off-farm activities. The results also show that the participation rate among part-owner operators is high partly because the availability of other income sources accelerates the process of acquiring assets to become full-owner operators.Labor and Human Capital,
SEARCH THEORY RISK PREFERENCE AND FARMLAND PRESERVATION
This paper uses search theory to examine the role that risk preference (RP) plays in farmland preservation. Assuming that the distribution of the offer price is fixed, the analysis indicates that risk-averse agents have lower reservation prices than risk-neutral agents, and that agricultural land held by the former exits farming at a faster rate. The results also show that farmland preservation policies which increase reservation prices have a greater capitalization effect if agents are risk-loving, and that such policies, while effectively protecting the interest of land speculators, may be less effective in serving the needs of farming and farm-held open space.Risk and Uncertainty,
Correlation between electrons and vortices in quantum dots
Exact many-body wave functions for quantum dots containing up to four
interacting electrons are computed and we investigated the distribution of the
wave function nodes, also called vortices. For this purpose, we evaluate the
reduced wave function by fixing the positions of all but one electron and
determine the locations of its zeros. We find that the zeros are strongly
correlated with respect to each other and with respect to the position of the
electrons and formulate rules describing their distribution. No multiple zeros
are found, i.e. vortices with vorticity larger than one. Our exact calculations
are compared to results extracted from the recently proposed rotating electron
molecule (REM) wave functions
Accuracy of the Hartree-Fock method for Wigner molecules at high magnetic fields
Few-electron systems confined in two-dimensional parabolic quantum dots at
high magnetic fields are studied by the Hartree-Fock (HF) and exact
diagonalization methods. A generalized multicenter Gaussian basis is proposed
in the HF method. A comparison of the HF and exact results allows us to discuss
the relevance of the symmetry of the charge density distribution for the
accuracy of the HF method. It is shown that the energy estimates obtained with
the broken-symmetry HF wave functions become exact in the infinite
magnetic-field limit. In this limit the charge density of the broken-symmetry
solution can be identified with the classical charge distribution.Comment: to appear in EPJ
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