3,632 research outputs found
Production Incentives from Static Decoupling: Entry, Exit and Use Exclusion Restrictions
The use of agricultural decoupled support has increased as World Trade Organization (WTO) member nations implement less trade distortive policies. However, the true production effects of these policies are still unclear. We show how the exclusion restrictions of U.S. direct payments, namely, the fruit and vegetable restriction and the requirement of keeping land in good agricultural use, cause the decoupled payment to become fully coupled over time as relative profits adjust. Theoretically, decoupled payments can be more trade distorting than an equivalent (same level of taxpayer expenditure) fully coupled subsidy.decoupled payments, infra-marginal support, cross-subsidization, Agricultural and Food Policy, International Relations/Trade, Land Economics/Use, Q15, Q17, Q18,
Cross-Subsidization and Exit Deterrence due to Infra-Marginal Support: Implications for Agricultural Policy Analysis
Agricultural and Food Policy,
How Do Health and Social Insurance Programs Affect the Land and Labor Allocations of Farm Households? Evidence from Taiwan
Using a unique dataset of 703,287 farm operators from the Taiwanese Census of Agriculture merged to administrative records from the National Farmers' Health Insurance (FHI) program, we examine the effects of the enrollment in the FHI program on farmers’ on- and off-farm labor supply and the amount of land they allocate to Taiwan’s land retirement program. In order to account for non-random self-selection into the FHI we use a matching procedure to estimate the impact of the program on land and labor allocations. Our results indicate that participation in the FHI increases (decrease) on (off) farm labor supply, and decreases the amount of land enrolled in the land retirement program. Our findings have implication for health care reforms that have been initiated in other countries, and the United States in particular.National Farmer's Health Insurance Program, labor supply, land retirement program, Taiwan., Agricultural and Food Policy, Health Economics and Policy, Labor and Human Capital,
Consumer Financed Export Subsidies and the Agreement on Agriculture
International Relations/Trade,
Ring Expansion Of Alkylidenecarbenes Derived From Lactams, Lactones, And Thiolactones Into Strained Heterocyclic Alkynes: A Theoretical Study
Strained cycloalkynes are of considerable interest to theoreticians and experimentalists, and possess much synthetic value as well. Herein, a series of cyclic alkylidenecarbenes—formally obtained by replacing the carbonyl oxygen of four-, five-, and six-membered lactams, lactones, and thiolactones with a divalent carbon—were modeled at the CCSD(T)/cc-pVTZ//B3LYP/6-311+G** and CCSD(T)/cc-pVTZ//CCSD/6-311+G** levels of theory. The singlet carbenes were found to be more stable than the triplets. The strained heterocyclic alkynes formed by ring expansion of these singlet carbenes were also modeled. Interestingly, the C≡C bonds in the five-membered heterocycles, obtained from the rearrangement of β-lactam- and β-lactone-derived alkylidenecarbenes, displayed lengths intermediate between formal double and triple bonds. Furthermore, 2-(1-azacyclobutylidene)carbene was found to be nearly isoenergetic with its ring-expanded isomer, and 1-oxacyclopent-2-yne was notably higher in energy than its precursor carbene. In all other cases, the cycloalkynes were lower in energy than the corresponding carbenes. The transition states for ring-expansion were always lower for the 1,2-carbon shifts than for 1,2-nitrogen or oxygen shifts, but higher than for the 1,2-sulfur shifts. These predictions should be verifiable using carbenes bearing appropriate isotopic labels. Computed vibrational spectra for the carbenes, and their ring-expanded isomers, are presented and could be of value to matrix isolation experiments
The X-ray Properties of the Most-Luminous Quasars from the Sloan Digital Sky Survey
Utilizing 21 new Chandra observations as well as archival Chandra, ROSAT, and
XMM-Newton data, we study the X-ray properties of a representative sample of 59
of the most optically luminous quasars in the Universe (M_i~~-29.3 to -30.2)
spanning a redshift range of z~~1.5-4.5. Our full sample consists of 32 quasars
from the Sloan Digital Sky Survey (SDSS) Data Release 3 (DR3) quasar catalog,
two additional objects in the DR3 area that were missed by the SDSS selection
criteria, and 25 comparably luminous quasars at z>~4. This is the largest X-ray
study of such luminous quasars to date. By jointly fitting the X-ray spectra of
our sample quasars, excluding radio-loud and broad absorption line (BAL)
objects, we find a mean X-ray power-law photon index of
Gamma=1.92^{+0.09}_{-0.08} and constrain any neutral intrinsic absorbing
material to have a mean column density of N_H<~2x10^{21} cm^{-2}. We find,
consistent with other studies, that Gamma does not change with redshift, and we
constrain the amount of allowed Gamma evolution for the most-luminous quasars.
Our sample, excluding radio-loud and BAL quasars, has a mean X-ray-to-optical
spectral slope of a_ox=-1.80+/-0.02, as well as no significant evolution of
a_ox with redshift. We also comment upon the X-ray properties of a number of
notable quasars, including an X-ray weak quasar with several strong narrow
absorption-line systems, a mildly radio-loud BAL quasar, and a well-studied
gravitationally lensed quasar.Comment: 18 pages (emulateapj), 11 figures. Accepted for publication in The
Astrophysical Journa
Tea: A High-level Language and Runtime System for Automating Statistical Analysis
Though statistical analyses are centered on research questions and
hypotheses, current statistical analysis tools are not. Users must first
translate their hypotheses into specific statistical tests and then perform API
calls with functions and parameters. To do so accurately requires that users
have statistical expertise. To lower this barrier to valid, replicable
statistical analysis, we introduce Tea, a high-level declarative language and
runtime system. In Tea, users express their study design, any parametric
assumptions, and their hypotheses. Tea compiles these high-level specifications
into a constraint satisfaction problem that determines the set of valid
statistical tests, and then executes them to test the hypothesis. We evaluate
Tea using a suite of statistical analyses drawn from popular tutorials. We show
that Tea generally matches the choices of experts while automatically switching
to non-parametric tests when parametric assumptions are not met. We simulate
the effect of mistakes made by non-expert users and show that Tea automatically
avoids both false negatives and false positives that could be produced by the
application of incorrect statistical tests.Comment: 11 page
Role of unstable periodic orbits in phase transitions of coupled map lattices
The thermodynamic formalism for dynamical systems with many degrees of
freedom is extended to deal with time averages and fluctuations of some
macroscopic quantity along typical orbits, and applied to coupled map lattices
exhibiting phase transitions. Thereby, it turns out that a seed of phase
transition is embedded as an anomalous distribution of unstable periodic
orbits, which appears as a so-called q-phase transition in the spatio-temporal
configuration space. This intimate relation between phase transitions and
q-phase transitions leads to one natural way of defining transitions and their
order in extended chaotic systems. Furthermore, a basis is obtained on which we
can treat locally introduced control parameters as macroscopic ``temperature''
in some cases involved with phase transitions.Comment: 13 pages, 9 figures; further explanation and 2 figures are added
(minor revision
Continued-fraction expansion of eigenvalues of generalized evolution operators in terms of periodic orbits
A new expansion scheme to evaluate the eigenvalues of the generalized
evolution operator (Frobenius-Perron operator) relevant to the
fluctuation spectrum and poles of the order- power spectrum is proposed. The
``partition function'' is computed in terms of unstable periodic orbits and
then used in a finite pole approximation of the continued fraction expansion
for the evolution operator. A solvable example is presented and the approximate
and exact results are compared; good agreement is found.Comment: CYCLER Paper 93mar00
The Isomorphism Relation Between Tree-Automatic Structures
An -tree-automatic structure is a relational structure whose domain
and relations are accepted by Muller or Rabin tree automata. We investigate in
this paper the isomorphism problem for -tree-automatic structures. We
prove first that the isomorphism relation for -tree-automatic boolean
algebras (respectively, partial orders, rings, commutative rings, non
commutative rings, non commutative groups, nilpotent groups of class n >1) is
not determined by the axiomatic system ZFC. Then we prove that the isomorphism
problem for -tree-automatic boolean algebras (respectively, partial
orders, rings, commutative rings, non commutative rings, non commutative
groups, nilpotent groups of class n >1) is neither a -set nor a
-set
- …