57,480 research outputs found
Explaining Changes in the Distribution of Annual Dairy Farm Income over Time
This paper identifies factors affecting the distribution of farm income among dairy producers over time. Using data from participants in Cornell's Dairy Farm Record Program, we decompose differences of farm income distributions into those due to: differences in means of observable farm characteristics, differential marginal effects of characteristics and unobserved random error. The distribution of farm income is affected by factors reflecting the operators' experience and investment in human capital and indicators of management efficiency and level of capital investment. The marked changes in marginal contributions of these factors explain most of the total change in the distribution of income.Dairy farm income distribution, Decomposition, Farm Management, Livestock Production/Industries,
Larkin-Ovchinnikov-Fulde-Ferrell phase in the superconductor (TMTSF)2ClO4: Theory versus experiment
We consider a formation of the Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) phase
in a quasi-one-dimensional (Q1D) conductor in a magnetic field, parallel to its
conducting chains, where we take into account both the paramagnetic
spin-splitting and orbital destructive effects against superconductivity. We
show that, due to a relative weakness of the orbital effects in a Q1D case, the
LOFF phase appears in (TMTSF)ClO superconductor for real values of its
Q1D band parameters. We compare our theoretical calculations with the recent
experimental data by Y. Maeno's group [S. Yonezawa et al., Phys. Rev. Lett.
\textbf{100}, 117002 (2008)] and show that there is a good qualitative and
quantitative agreement between the theory and experimental data.Comment: 4 pages, 1 figur
Repulsive Fermions in Optical Lattices: Phase separation versus Coexistence of Antiferromagnetism and d-Superfluidity
We investigate a system of fermions on a two-dimensional optical square
lattice in the strongly repulsive coupling regime. In this case, the
interactions can be controlled by laser intensity as well as by Feshbach
resonance. We compare the energetics of states with resonating valence bond
d-wave superfluidity, antiferromagnetic long range order and a homogeneous
state with coexistence of superfluidity and antiferromagnetism. We show that
the energy density of a hole has a minimum at doping that
signals phase separation between the antiferromagnetic and d-wave paired
superfluid phases. The energy of the phase-separated ground state is however
found to be very close to that of a homogeneous state with coexisting
antiferromagnetic and superfluid orders. We explore the dependence of the
energy on the interaction strength and on the three-site hopping terms and
compare with the nearest neighbor hopping {\it t-J} model
Partition Function Zeros of a Restricted Potts Model on Lattice Strips and Effects of Boundary Conditions
We calculate the partition function of the -state Potts model
exactly for strips of the square and triangular lattices of various widths
and arbitrarily great lengths , with a variety of boundary
conditions, and with and restricted to satisfy conditions corresponding
to the ferromagnetic phase transition on the associated two-dimensional
lattices. From these calculations, in the limit , we determine
the continuous accumulation loci of the partition function zeros in
the and planes. Strips of the honeycomb lattice are also considered. We
discuss some general features of these loci.Comment: 12 pages, 12 figure
Some Exact Results on the Potts Model Partition Function in a Magnetic Field
We consider the Potts model in a magnetic field on an arbitrary graph .
Using a formula of F. Y. Wu for the partition function of this model as a
sum over spanning subgraphs of , we prove some properties of concerning
factorization, monotonicity, and zeros. A generalization of the Tutte
polynomial is presented that corresponds to this partition function. In this
context we formulate and discuss two weighted graph-coloring problems. We also
give a general structural result for for cyclic strip graphs.Comment: 5 pages, late
TIFA, an inflammatory signaling adaptor, is tumor suppressive for liver cancer.
TIFA (TNF receptor associated factor (TRAF)-interacting protein with a Forkhead-associated (FHA) domain), also called T2BP, was first identified using a yeast two-hybrid screening. TIFA contains a FHA domain, which directly binds phosphothreonine and phosphoserine, and a consensus TRAF6-binding motif. TIFA-mediated oligomerization and poly-ubiquitinylation of TRAF6 mediates signaling downstream of the Tumor necrosis factor alpha receptor 1 (TNFaR-I) and interleukin-1/Toll-like receptor 4 (TLR4) pathways. Examining TIFA expression in hepatocellular carcinoma (HCC) tissues microarrays, we noted marked decreases TIFA reactivity in tumor versus control samples. In agreement, we found that HCC cell lines show reduced TIFA expression levels versus normal liver controls. Reconstituting TIFA expression in HCC cell lines promoted two independent apoptosis signaling pathways: the induction of p53 and cell cycle arrest, and the activation of caspase-8 and caspase-3. In contrast, the expression of a non-oligomerizing mutant of TIFA impacted cells minimally, and suppression of TIFA expression protected cells from apoptosis. Mice bearing TIFA overexpression hepatocellular xenografts develop smaller tumors versus TIFA mutant tumors; terminal deoxynucleotidyl transferase dUTP nick end labeling staining demonstrates increased cell apoptosis, and decreased proliferation, reflecting cell cycle arrest. Interestingly, p53 has a greater role in decreased proliferation than cell death, as it appeared dispensable for TIFA-induced cell killing. The findings demonstrate a novel suppressive role of TIFA in HCC progression via promotion of cell death independent of p53
Molecular-beam epitaxy of CrSi_2 on Si(111)
Chromium disilicide layers have been grown on Si(111) in a commercial molecularâbeam epitaxy machine. Thin layers (10 nm) exhibit two epitaxial relationships, which have been identified as CrSi_2(0001)//Si(111) with CrSi_2[1010]//Si[101], and CrSi_2(0001)//Si(111) with CrSi_2[1120]//Si[101]. The latter case represents a 30° rotation of the CrSi_2 layer about the Si surface normal relative to the former case. Thick (210 nm) layers were grown by four different techniques, and the bestâquality layer was obtained by codeposition of Cr and Si at an elevated temperature. These layers are not single crystal; the largest grains are observed in a layer grown at 825â°C and are 1â2 ÎŒm across
Towards a CPT Invariant Quantum Field Theory on Elliptic de Sitter Space
Consequences of Schr\"{o}dinger's antipodal identification on quantum field
theory in de Sitter space are investigated. The elliptic
identification provides observers with complete information. We show that a
suitable confinement on dimension of the elliptic de Sitter space guarantees
the existence of globally defined spinors and orientable
manifold. In Beltrami coordinates, we give exact solutions of scalar and spinor
fields. The CPT invariance of quantum field theory on the elliptic de Sitter
space is presented explicitly.Comment: 16 pages, some references have been added, the structure of paper
have been revised, accepted for publication in Int. J. Mod. Phys.
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