515 research outputs found
FARM DECISION-MAKING IN A MULTIFUNCTIONAL CONTEXT: THE CASE OF CONVENTIONAL AND ORGANIC FARMING IN KERKINI DISTRICT, GREECE
Multifuncionality has become a central concern at both conceptual and empirical levels. In this study, a comparative evaluation of the economic performance of conventional and multifunctional farms (mainly organic farms) was conducted for Lake Kerkini region (North Greece) with the use of mixed integer non-linear programming method. Economic performance was evaluated in terms of farm income, resource allocation, production level etc. The results indicate that multifunctional farms have overall better economic performance and young farm managers are keener to adopt multifunctional farming than the older ones.Greek farming, Multifunctionality of farming, Farm, Farm decision making and age of farmers, Agribusiness, Community/Rural/Urban Development, Farm Management,
A Bayesian approach to the analysis of time symmetry in light curves: Reconsidering Scorpius X-1 occultations
We present a new approach to the analysis of time symmetry in light curves,
such as those in the x-ray at the center of the Scorpius X-1 occultation
debate. Our method uses a new parameterization for such events (the bilogistic
event profile) and provides a clear, physically relevant characterization of
each event's key features. We also demonstrate a Markov Chain Monte Carlo
algorithm to carry out this analysis, including a novel independence chain
configuration for the estimation of each event's location in the light curve.
These tools are applied to the Scorpius X-1 light curves presented in Chang et
al. (2007), providing additional evidence based on the time series that the
events detected thus far are most likely not occultations by TNOs.Comment: 24 pages, 18 figures. Preprint typeset using LaTeX style emulateapj
v. 04/20/0
The Parallel Boundary Condition for Turbulence Simulations in Low Magnetic Shear Devices
Flux tube simulations of plasma turbulence in stellarators and tokamaks
typically employ coordinates which are aligned with the magnetic field lines.
Anisotropic turbulent fluctuations can be represented in such field-aligned
coordinates very efficiently, but the resulting non-trivial boundary conditions
involve all three spatial directions, and must be handled with care. The
standard "twist-and-shift" formulation of the boundary conditions [Beer,
Cowley, Hammett \textit{Phys. Plasmas} \textbf{2}, 2687 (1995)] was derived
assuming axisymmetry and is widely used because it is efficient, as long as the
global magnetic shear is not too small. A generalization of this formulation is
presented, appropriate for studies of non-axisymmetric, stellarator-symmetric
configurations, as well as for axisymmetric configurations with small global
shear. The key idea is to replace the "twist" of the standard approach (which
accounts only for global shear) with the integrated local shear. This
generalization allows one significantly more freedom when choosing the extent
of the simulation domain in each direction, without losing the natural
efficiency of field-line-following coordinates. It also corrects errors
associated with naive application of axisymmetric boundary conditions to
non-axisymmetric configurations. Simulations of stellarator turbulence that
employ the generalized boundary conditions require much less resolution than
simulations that use the (incorrect, axisymmetric) boundary conditions. We also
demonstrate the surprising result that (at least in some cases) an easily
implemented but manifestly incorrect formulation of the boundary conditions
does {\it not} change important predicted quantities, such as the turbulent
heat flux
Further application of a semi-microscopic core-particle coupling method to the properties of Gd155,157, and Dy159
In a previous paper a semi-microscopic core-particle coupling method that
includes the conventional strong coupling core-particle model as a limiting
case, was applied to spectra and electromagnetic properties of several
well-deformed odd nuclei. This work, coupled a large single-particle space to
the ground state bands of the neighboring even cores. In this paper, we
generalize the theory to include excited bands of the cores, such as beta and
gamma bands, and thereby show that the resulting theory can account for the
location and structure of all bands up to about 1.5 MeV.Comment: 15 pages including 9 figure(postscript), submitted to Phys.Rev.
On non-QRT Mappings of the Plane
We construct 9-parameter and 13-parameter dynamical systems of the plane
which map bi-quadratic curves to other bi-quadratic curves and return to the
original curve after two iterations. These generalize the QRT maps which map
each such curve to itself. The new families of maps include those that were
found as reductions of integrable lattices
The impact of corporate philanthropy on reputation for corporate social performance
This study seeks to examine the mechanisms by which a corporation’s use of philanthropy affects its reputation for corporate social performance (CSP), which the authors conceive of as consisting of two dimensions: CSP awareness and CSP perception. Using signal detection theory (SDT), the authors model signal amplitude (the amount contributed), dispersion (number of areas supported), and consistency (presence of a corporate foundation) on CSP awareness and perception. Overall, this study finds that characteristics of firms' portfolio of philanthropic activities are a greater predictor of CSP awareness than of CSP perception. Awareness increases with signal amplitude, dispersion, and consistency. CSP perception is driven by awareness and corporate reputation. The authors’ contention that corporate philanthropy is a complex variable is upheld, as we find that CSP signal characteristics influence CSP awareness and perception independently and asymmetrically. The authors conclude by proposing avenues for future research
Transmit Antenna Selection for Massive MIMO Systems
In this paper, particle swarm optimization is employed to carry out transmit antenna subgrouping algorithm for massive multiple input and multiple output (MIMO) system. A minimum number of transmit antenna elements are selected to achieve a similar quality of service (QoS) as that of a single user MIMO system. Simulation results show that our proposed algorithm achieves similar capacity performance as compared to massive MIMO systems when employing exhaustive search for transmit antenna selection
The finite temperature QCD using 2+1 flavors of domain wall fermions at N_t = 8
We study the region of the QCD phase transition using 2+1 flavors of domain
wall fermions (DWF) and a lattice volume with a fifth dimension
of . The disconnected light quark chiral susceptibility, quark number
susceptibility and the Polyakov loop suggest a chiral and deconfining crossover
transition lying between 155 and 185 MeV for our choice of quark mass and
lattice spacing. In this region the lattice scale deduced from the Sommer
parameter is GeV, the pion mass is MeV
and the kaon mass is approximately physical. The peak in the chiral
susceptibility implies a pseudo critical temperature MeV
where the first error is associated with determining the peak location and the
second with our unphysical light quark mass and non-zero lattice spacing. The
effects of residual chiral symmetry breaking on the chiral condensate and
disconnected chiral susceptibility are studied using several values of the
valence .Comment: 41 pages, 10 tables, 13 figure
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