16,151 research outputs found
The Behavioral Firm and Its Internal Game: Evolutionary Dynamics of Decision Making
In this paper the firm is analyzed and modeled as a set of different subcoalitions (agents) each with their own objectives. It examines how the goals can be conflicting and in turn how this influences the payoff structure of the subcoalitions given that they follow 'simple' decision rules, i.e. rules of thumb. This implies that the subcoalitions act in aboundedly rational way. To see how these decision making procedures evolve we make use of an (evolutionary) dynamic game theoretical framework. Consequently, the main aim is to address the issue of modeling the dynamic and adaptive nature of the subcoalitions
The effect of core polarization on longitudinal form factors in B
Electron scattering Coulomb form factors for the single-particle quadrupole
transitions in -shell B nucleus have been studied. Core polarization
effects are included through a microscopic theory that includes excitations
from the core orbits up to higher orbits with 2 excitations. The
modified surface delta interaction (MSDI) is employed as a residual
interaction. The effect of core polarization is found essential in both the
transition strengths and momentum transfer dependence of form factors, and
gives a remarkably good agreement with the measured data with no adjustable
parameters.Comment: 4 pages, 5 figure
Laboratory mid-IR spectra of equilibrated and igneous meteorites. Searching for observables of planetesimal debris
Meteorites contain minerals from Solar System asteroids with different
properties (like size, presence of water, core formation). We provide new
mid-IR transmission spectra of powdered meteorites to obtain templates of how
mid-IR spectra of asteroidal debris would look like. This is essential for
interpreting mid-IR spectra of past and future space observatories, like the
James Webb Space Telescope. We show that the transmission spectra of wet and
dry chondrites, carbonaceous and ordinary chondrites and achondrite and
chondrite meteorites are distinctly different in a way one can distinguish in
astronomical mid-IR spectra. The two observables that spectroscopically
separate the different meteorites groups (and thus the different types of
parent bodies) are the pyroxene-olivine feature strength ratio and the peak
shift of the olivine spectral features due to an increase in the iron
concentration of the olivine
Towards a Soil Information System with quantified accuracy : a prototype for mapping continuous soil properties
This report describes the potential and functionality of software for spatial analysis, prediction and stochastic simulation of continuous soil properties using data from the Dutch Soil Information System (BIS). A geostatistical framework and R codes were developed. The geostatistical model of a soil property has a deterministic component representing the mean value within a soil category, and a stochastic component of standardized residuals. The standardized residuals are interpolated or simulated based on the simple kriging system. The software was tested in four case studies: exchangeable soil pH, clay content, organic matter content and Mean Spring Water table depth (MSW). It is concluded that the geostatistical framework and R codes developed in this study enable to predict values of continuous soil properties spatially, and to quantify the inaccuracy of these predictions. The inaccuracy of a spatial prediction at a certain location is quantified by the kriging variance, which can be interpreted as an indication of the uncertainty about the true value
Practical Aspects of Carbon-Carbon Cross-Coupling Reactions Using Heteroarenes
The use of cross-coupling reactions for the preparation of alkylated and arylated heteroaromatic compounds has increased tremendously over the past two decades. This has been driven on the one hand by the increasingly complex structures of new drugs, most of which contain one or more heterocyclic motifs. On the other hand, the development of new catalysts and reaction conditions for these reactions has rendered even the most unreactive of heteroarenes amenable to cross-coupling chemistry. Not only have new bulky electron-donating ligands been created that allow the coupling of aryl chlorides under mild conditions, but also the use of ligand-free palladium, in particular at very low doses, sometimes called homeopathic palladium, has served to bring down the cost of these reactions. More recent and enabling developments are the use of catalysts based on cheap metals such as nickel, copper, and iron. Scale-up issues are availability and cost of starting materials, cost of the catalysts (related to cost of the metal and the ligand, intrinsic activity and stability of the catalyst), solvent choice, and removal of the metal t
The Astrophysical Multipurpose Software Environment
We present the open source Astrophysical Multi-purpose Software Environment
(AMUSE, www.amusecode.org), a component library for performing astrophysical
simulations involving different physical domains and scales. It couples
existing codes within a Python framework based on a communication layer using
MPI. The interfaces are standardized for each domain and their implementation
based on MPI guarantees that the whole framework is well-suited for distributed
computation. It includes facilities for unit handling and data storage.
Currently it includes codes for gravitational dynamics, stellar evolution,
hydrodynamics and radiative transfer. Within each domain the interfaces to the
codes are as similar as possible. We describe the design and implementation of
AMUSE, as well as the main components and community codes currently supported
and we discuss the code interactions facilitated by the framework.
Additionally, we demonstrate how AMUSE can be used to resolve complex
astrophysical problems by presenting example applications.Comment: 23 pages, 25 figures, accepted for A&
Investigating the interstellar dust through the Fe K-edge
The chemical and physical properties of interstellar dust in the densest
regions of the Galaxy are still not well understood. X-rays provide a powerful
probe since they can penetrate gas and dust over a wide range of column
densities (up to ). The interaction (scattering and
absorption) with the medium imprints spectral signatures that reflect the
individual atoms which constitute the gas, molecule, or solid. In this work we
investigate the ability of high resolution X-ray spectroscopy to probe the
properties of cosmic grains containing iron. Although iron is heavily depleted
into interstellar dust, the nature of the Fe-bearing grains is still largely
uncertain. In our analysis we use iron K-edge synchrotron data of minerals
likely present in the ISM dust taken at the European Synchrotron Radiation
Facility. We explore the prospects of determining the chemical composition and
the size of astrophysical dust in the Galactic centre and in molecular clouds
with future X-ray missions. The energy resolution and the effective area of the
present X-ray telescopes are not sufficient to detect and study the Fe K-edge,
even for bright X-ray sources. From the analysis of the extinction cross
sections of our dust models implemented in the spectral fitting program SPEX,
the Fe K-edge is promising for investigating both the chemistry and the size
distribution of the interstellar dust. We find that the chemical composition
regulates the X-ray absorption fine structures in the post edge region, whereas
the scattering feature in the pre-edge is sensitive to the mean grain size.
Finally, we note that the Fe K-edge is insensitive to other dust properties,
such as the porosity and the geometry of the dust.Comment: 11 pages, 10 figures. Accepted for publication in Astronomy and
Astrophysic
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