2,617 research outputs found
Spatial Econometric Issues for Bio-Economic and Land-Use Modeling
We survey the literature on spatial bio-economic and land-use modelling and review thematic developments. Unobserved site-specific heterogeneity is common in almost all of the surveyed works. Heterogeneity appears also to be a significant catalyst engendering significant methodological innovation. To better equip prototypes to adequately incorporate heterogeneity, we consider a smorgasbord of extensions. We highlight some problems arising with their application; provide Bayesian solutions to some; and conjecture solutions for others.spatial econometrics, bio-economic and land-use modelling, Bayesian solution, Land Economics/Use,
Boundary interactions changing operators and dynamical correlations in quantum impurity problems
Recent developments have made possible the computation of equilibrium
dynamical correlators in quantum impurity problems. In many situations however,
one is rather interested in correlators subject to a non equilibrium initial
preparation; this is the case for instance for the occupation probability
in the double well problem of dissipative quantum mechanics (DQM). We
show in this paper how to handle this situation in the framework of integrable
quantum field theories by introducing ``boundary interactions changing
operators''. We determine the properties of these operators by using an
axiomatic approach similar in spirit to what is done for form-factors. This
allows us to obtain new exact results for ; for instance, we find that
that at large times (or small ), the leading behaviour for g < 1/2} is
, with the universal ratio.
.Comment: 4 pages, revte
Exact Friedel oscillations in the g=1/2 Luttinger liquid
A single impurity in the 1D Luttinger model creates a local modification of
the charge density analogous to the Friedel oscillations. In this paper, we
present an exact solution of the case (the equivalent of the
Toulouse point) at any temperature and impurity coupling, expressing the
charge density in terms of a hypergeometric function. We find in particular
that at , the oscillatory part of the density goes as at small
distance and at large distance.Comment: 1 reference added. 13 pages, harvma
Coherence correlations in the dissipative two-state system
We study the dynamical equilibrium correlation function of the
polaron-dressed tunneling operator in the dissipative two-state system. Unlike
the position operator, this coherence operator acts in the full
system-plus-reservoir space. We calculate the relevant modified influence
functional and present the exact formal expression for the coherence
correlations in the form of a series in the number of tunneling events. For an
Ohmic spectral density with the particular damping strength , the series
is summed in analytic form for all times and for arbitrary values of
temperature and bias. Using a diagrammatic approach, we find the long-time
dynamics in the regime . In general, the coherence correlations decay
algebraically as at T=0. This implies that the linear static
susceptibility diverges for as , whereas it stays finite for
in this limit. The qualitative differences with respect to the
asymptotic behavior of the position correlations are explained.Comment: 19 pages, 4 figures, to be published in Phys. Rev.
Transfer of recessive skr crossability trait into well-adapted French wheat cultivar Barok through marker-assisted backcrossing method
In order to increase genetic diversity in cereals, interspecific or even intergeneric crosses are worthwhile, especially wheat by rye crosses for triticale production. However, these crosses often fail due to inhibiting genes. To overcome this obstacle, crossability trait, present in a few wheat cultivars, can be transferred into other wheat lines of agronomical interest. Nevertheless, this transfer remains tedious through conventional backcrossing methods because it is a recessive trait, which requires selfing generations and complex evaluation by many crosses. Here, we present a marker-assisted backcrossing method to transfer this trait more quickly and easily. We chose to introduce the recessive crossability skr, located on chromosome 5BS and originating from Asian wheat, into Barok, a non-crossable French wheat cultivar, with good agronomic characteristics. Six molecular markers, close to the Skr locus, were used to check the transfer of the gene at each of the three backcrosses, without selfing generation nor crosses with rye. Finally, we crossed the predicted crossable lines with rye to validate their crossability. We obtained sixteen lines, morphologically similar to Barok, exhibiting high crossability rate (30%). The markers were thus efficient to transfer the skr crossability but they remain too far from the Skr locus to be considered as diagnostic markers. Indeed, genotyping and phenotyping on other wheat cultivars showed some discrepancies. Nevertheless, this opens the way to enhance genetic diversity more easily and to improve traits of agronomic interest in triticale or wheat as well as to study further barriers to intergeneric crosses
Form-factors computation of Friedel oscillations in Luttinger liquids
We show how to analytically determine for the "Friedel
oscillations" of charge density by a single impurity in a 1D Luttinger liquid
of spinless electrons.Comment: Revtex, epsf, 4pgs, 2fig
Geodetic and tectonic analyses along an active plate boundary : the central Gulf of California
MASCARA-2 b: A hot Jupiter transiting the A-star HD185603
In this paper we present MASCARA-2 b, a hot Jupiter transiting the
A2 star HD 185603. Since early 2015, MASCARA has taken more than 1.6 million
flux measurements of the star, corresponding to a total of almost 3000 hours of
observations, revealing a periodic dimming in the flux with a depth of .
Photometric follow-up observations were performed with the NITES and IAC80
telescopes and spectroscopic measurements were obtained with the Hertzsprung
SONG telescope. We find MASCARA-2 b orbits HD 185603 with a period of
at a distance of , has a radius of and place a
upper limit on the mass of . HD 185603 is a
rapidly rotating early-type star with an effective temperature of
and a mass and radius of
, , respectively. Contrary
to most other hot Jupiters transiting early-type stars, the projected planet
orbital axis and stellar spin axis are found to be aligned with . The brightness of the host star and the high equilibrium
temperature, , of MASCARA-2 b make it a suitable target for
atmospheric studies from the ground and space. Of particular interest is the
detection of TiO, which has recently been detected in the similarly hot planets
WASP-33 b and WASP-19 b.Comment: 8 pages, 4 figures, Accepted for publication in A&
The Transition Between Quantum Coherence and Incoherence
We show that a transformed Caldeira-Leggett Hamltonian has two distinct
families of fixed points, rather than a single unique fixed point as often
conjectured based on its connection to the anisotropic Kondo model. The two
families are distinguished by a sharp qualitative difference in their quantum
coherence properties and we argue that this distinction is best understood as
the result of a transition in the model between degeneracy and non-degeneracy
in the spectral function of the ``spin-flip'' operator.Comment: some typos corrected and a reference adde
Solving 1d plasmas and 2d boundary problems using Jack polynomials and functional relations
The general one-dimensional ``log-sine'' gas is defined by restricting the
positive and negative charges of a two-dimensional Coulomb gas to live on a
circle. Depending on charge constraints, this problem is equivalent to
different boundary field theories. We study the electrically neutral case,
which is equivalent to a two-dimensional free boson with an impurity cosine
potential. We use two different methods: a perturbative one based on Jack
symmetric functions, and a non-perturbative one based on the thermodynamic
Bethe ansatz and functional relations. The first method allows us to compute
explicitly all coefficients in the virial expansion of the free energy and the
experimentally-measurable conductance. Some results for correlation functions
are also presented. The second method provides in particular a surprising
fluctuation-dissipation relation between the free energy and the conductance.Comment: 19 page
- âŠ