7,239 research outputs found
Classification of bi-qutrit positive partial transpose entangled edge states by their ranks
We construct PPT entangled edge states with maximal ranks, to
complete the classification of PPT entangled edge states by their
types. The ranks of the states and their partial transposes are 8 and 6,
respectively. These examples also disprove claims in the literature.Comment: correct the title to avoid an acronym, correct few text
Boundary correlation function of fixed-to-free bcc operators in square-lattice Ising model
We calculate the boundary correlation function of fixed-to-free boundary
condition changing operators in the square-lattice Ising model. The correlation
function is expressed in four different ways using block Toeplitz
determinants. We show that these can be transformed into a scalar Toeplitz
determinant when the size of the matrix is even. To know the asymptotic
behavior of the correlation function at large distance we calculate the
asymptotic behavior of this scalar Toeplitz determinant using the Szeg\"o's
theorem and the Fisher-Hartwig theorem. At the critical temperature we confirm
the power-law behavior of the correlation function predicted by conformal field
theory
Discovery Of Ethanol-Responsive Small Rnas In Zymomonas Mobilis
Zymomonas mobilis is a bacterium that can produce ethanol by fermentation. Due to its unique metabolism and efficient ethanol production, Z. mobilis has attracted special interest for biofuel energy applications; an important area of study is the regulation of those specific metabolic pathways. Small RNAs (sRNAs) have been studied as molecules that function as transcriptional regulators in response to cellular stresses. While sRNAs have been discovered in various organisms by computational prediction and experimental approaches, their discovery in Z. mobilis has not yet been reported. In this study, we have applied transcriptome analysis and computational predictions to facilitate identification and validation of 15 novel sRNAs in Z. mobilis. We furthermore characterized their expression in the context of high and low levels of intracellular ethanol. Here, we report that 3 of the sRNAs (Zms2, Zms4, and Zms6) are differentially expressed under aerobic and anaerobic conditions, when low and high ethanol productions are observed, respectively. Importantly, when we tested the effect of ethanol stress on the expression of sRNAs in Z. mobilis, Zms2, Zms6, and Zms18 showed differential expression under 5% ethanol stress conditions. These data suggest that in this organism regulatory RNAs can be associated with metabolic functions involved in ethanol stress responses.NSF CBET-1254754Welch Foundation F-1756Cellular and Molecular BiologyChemical Engineerin
Thermal activation energy of 3D vortex matter in NaFe1-xCoxAs (x=0.01, 0.03 and 0.07) single crystals
We report on the thermally activated flux flow dependency on the doping
dependent mixed state in NaFe1-xCoxAs (x=0.01, 0.03, and 0.07) crystals using
the magnetoresistivity in the case of B//c-axis and B//ab-plane. It was found
clearly that irrespective of the doping ratio, magnetoresistivity showed a
distinct tail just above the Tc, offset associated with the thermally activated
flux flow (TAFF) in our crystals. Furthermore, in TAFF region the temperature
dependence of the activation energy follows the relation U(T, B)=U_0 (B)
(1-T/T_c )^q with q=1.5 in all studied crystals. The magnetic field dependence
of the activation energy follows a power law of U_0 (B)~B^(-{\alpha}) where the
exponent {\alpha} is changed from a low value to a high value at a crossover
field of B=~2T, indicating the transition from collective to plastic pinning in
the crystals. Finally, it is suggested that the 3D vortex phase is the dominant
phase in the low-temperature region as compared to the TAFF region in our
series samples
Upper transition point for percolation on the enhanced binary tree: A sharpened lower bound
Hyperbolic structures are obtained by tiling a hyperbolic surface with
negative Gaussian curvature. These structures generally exhibit two percolation
transitions: a system-wide connection can be established at a certain
occupation probability and there emerges a unique giant cluster at
. There have been debates about locating the upper transition
point of a prototypical hyperbolic structure called the enhanced binary tree
(EBT), which is constructed by adding loops to a binary tree. This work
presents its lower bound as by using phenomenological
renormalization-group methods and discusses some solvable models related to the
EBT.Comment: 12 pages, 20 figure
Crystallography on Curved Surfaces
We study static and dynamical properties that distinguish two dimensional
crystals constrained to lie on a curved substrate from their flat space
counterparts. A generic mechanism of dislocation unbinding in the presence of
varying Gaussian curvature is presented in the context of a model surface
amenable to full analytical treatment. We find that glide diffusion of isolated
dislocations is suppressed by a binding potential of purely geometrical origin.
Finally, the energetics and biased diffusion dynamics of point defects such as
vacancies and interstitials is explained in terms of their geometric potential.Comment: 12 Pages, 8 Figure
Why Don't Country Elevators Pay Less for Low Quality Wheat? Information, Producer Preferences and Prospect Theory
Previous research found that country elevators that are the first in their area to grade wheat and pay quality-adjusted prices would receive above-normal profits at the expense of their competitors. Because of spatial monopsony, these early-adopting elevators would pass on to producers only 70% of the quality-based price differentials received from next-in-line buyers. If competing elevators also adopted these practices, profits for all elevators would return to near normal, and elevators would pass on to producers nearly all price differentials received from next-in-line buyers. However, that research could not explain why more elevators were not becoming "early adopters" by paying quality-adjusted prices. More recent research found that producers' risk aversion and lack of information about the quality of their wheat could explain more of the failure of country elevators to pass on premiums and discounts. If producers are risk averse, an elevator that imposes discounts for lower quality wheat, even while paying a higher price for high quality wheat, risks losing business if producers believe that a competing elevator may be more likely to pay them a higher price net of discounts. However, even more important is the level of information producers have about the quality of their wheat before selling it to an elevator. Still, these explanations account for only part of elevators' apparent reluctance to pay quality-adjusted prices. Since inconsistencies have been observed between expected utility and individuals' behavior, this research considers the case where producers' preferences can be more appropriately modeled by prospect theory, and whether such preferences can explain more of elevators' reluctance to pay quality-adjusted prices. A simulation model is used to measure the effects of risk-averse producers (in both expected utility and prospect theory frameworks) and limited quality information on profits that can be earned by an elevator that pays quality-adjusted prices. Results indicate that prospect theory helps to explain part, but not all, of the reluctance to pay quality-adjusted prices.Crop Production/Industries, Demand and Price Analysis,
An effective thermodynamic potential from the instanton with Polyakov-loop contributions
We derive an effective thermodynamic potential (Omega_eff) at finite
temperature (T>0) and zero quark-chemical potential (mu_R=0), using the
singular-gauge instanton solution and Matsubara formula for N_c=3 and N_f=2 in
the chiral limit. The momentum-dependent constituent-quark mass is also
obtained as a function of T, employing the Harrington-Shepard caloron solution
in the large-N_c limit. In addition, we take into account the imaginary quark
chemical potential mu_I = A_4, translated as the traced Polayakov-loop (Phi) as
an order parameter for the Z(N_c) symmsetry, characterizing the confinement
(intact) and deconfinement (spontaneously broken) phases. As a result, we
observe the crossover of the chiral (chi) order parameter sigma^2 and Phi. It
also turns out that the critical temperature for the deconfinment phase
transition, T^Z_c is lowered by about (5-10)% in comparison to the case with a
constant constituent-quark mass. This behavior can be understood by
considerable effects from the partial chiral restoration and nontrivial QCD
vacuum on Phi. Numerical calculations show that the crossover transitions occur
at (T^chi_c,T^Z_c) ~ (216,227) MeV.Comment: 15 pages, 7 figure
RESULTS OF A FARM AND MARKET SURVEY FOR HMONG SPECIALTY CROP FARMERS IN THE MINNEAPOLIS, ST. PAUL METRO AREA
This report is part of a larger project, "Risk Management Education and Farm Management Development Program for Hmong Specialty Crop Farmers in the Minneapolis, St. Paul Metro Area," funded by the Risk Management Agency, U.S. Department of Agriculture. The project was designed to assist Hmong farmers in the Twin Cities area in improving their production and management practices so they are able to increase their economic viability and reduce their exposure to risk. As part of the overall project, 62 Hmong farmers and 69 customers at farmers markets were surveyed to determine the local specialty crop production and market conditions. The findings of these 2 surveys are contained in the report. The median size of the 62 farms surveyed farms was 3 acres. Forty-two percent of those farmers responding reported total farm product sales between 8,999. Few farmers indicated they were familiar with crop insurance programs. Sixty-eight percent of the 19 farmers responding (or 21% of the 62 surveyed) said they were familiar with multi-peril crop insurance (MPCI). Only 12% of the 50 farmers responding had bought crop insurance in 2002. The most frequently indicated needs for future education programs were production oriented: weed control, insect control, fertilization, and pesticide safety. All of the 69 customers surveyed regularly bought some kind of vegetables or herbs. Over half of the customers bought potatoes, snap beans, peppers, sweet corn, carrots, cucumbers, basil, and winter squash. Eighty-eight percent of customers indicated they typically spend between 29 on vegetables and herbs during each visit to a farmers' market.Crop Production/Industries,
Kaon semileptonic decay (K_{l3}) form factors from the instanton vacuum
We investigate the kaon semileptonic decay (K_{l3}) form factors within the
framework of the nonlocal chiral quark model from the instanton vacuum, taking
into account the effects of flavor SU(3) symmetry breaking. We also consider
the problem of gauge invariance arising from the momentum-dependent quark mass
in the present work. All theoretical calculations are carried out without any
adjustable parameter, the average instanton size (rho ~ 1/3 fm) and the
inter-instanton distance (R ~ 1 fm) having been fixed. We also show that the
present results satisfy the Callan-Treiman low-energy theorem as well as the
Ademollo-Gatto theorem. Using the K_{l3} form factors, we evaluate relevant
physical quantities. It turns out that the effects of flavor SU(3) symmetry
breaking are essential in reproducing the kaon semileptonic form factors. The
present results are in a good agreement with experiments, and are compatible
with other model calculations.Comment: 12 pages, 3 figures, submitted to PR
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