16,700 research outputs found
Incidence of Agro-Climate Variability over Grass-Fed Cattle Markets.
The marginal contribution of each of the selected variables was quantified in terms of premiums and discounts and mapped as dynamic iso-price regions that illustrate geographic and seasonal permanent price patterns for feeder cattle, as well as changing market conditions derived from unexpected climate and weather variability. The graphic representation of how price patterns may change with climate variability allows for a better understanding of short term market disequilibrium derived from this type of variability. This may help cattle operators and producers improve farm management and making informed decisions.cattle prices, climate variability, agro-ecological conditions, seasonal effects, price formation, differentiated products, Demand and Price Analysis, Livestock Production/Industries,
Altruistic behavior pays, or the importance of fluctuations in evolutionary game theory
Human behavior is one of the main problems for evolution, as it is often the
case that human actions are disadvantageous for the self and advantageous for
other people. Behind this puzzle are our beliefs about rational behavior, based
on game theory. Here we show that by going beyond the standard game-theoretical
conventions, apparently altruistic behavior can be understood as
self-interested. We discuss in detail an example related to the so called
Ultimatum game and illustrate the appearance of altruistic behavior induced by
fluctuations. In addition, we claim that in general settings, fluctuations play
a very relevant role, and we support this claim by considering a completely
different example, namely the Stag-Hunt game.Comment: For the proceedings of the 8th Granada Seminar on Computational
Physics (AIP Proceedeings Series
Density functional simulation of small Fe nanoparticles
We calculate from first principles the electronic structure, relaxation and
magnetic moments in small Fe particles, applying the numerical local orbitals
method in combination with norm-conserving pseudopotentials. The accuracy of
the method in describing elastic properties and magnetic phase diagrams is
tested by comparing benchmark results for different phases of crystalline iron
to those obtained by an all-electron method. Our calculations for the
bipyramidal Fe_5 cluster qualitatively and quantitatively confirm previous
plane-wave results that predicted a non-collinear magnetic structure. For
larger bcc-related (Fe_35) and fcc-related (Fe_38, Fe_43, Fe_62) particles, a
larger inward relaxation of outer shells has been found in all cases,
accompanied by an increase of local magnetic moments on the surface to beyond 3
mu_B.Comment: 15 pages with 6 embedded postscript figures, updated version,
submitted to Eur.Phys.J.
Band topology and quantum spin Hall effect in bilayer graphene
We consider bilayer graphene in the presence of spin orbit coupling, to
assess its behavior as a topological insulator. The first Chern number for
the energy bands of single and bilayer graphene is computed and compared. It is
shown that for a given valley and spin, in a bilayer is doubled with
respect to the monolayer. This implies that bilayer graphene will have twice as
many edge states as single layer graphene, which we confirm with numerical
calculations and analytically in the case of an armchair terminated surface.
Bilayer graphene is a weak topological insulator, whose surface spectrum is
susceptible to gap opening under spin-mixing perturbations. We also assess the
stability of the associated topological bulk state of bilayer graphene under
various perturbations. Finally, we consider an intermediate situation in which
only one of the two layers has spin orbit coupling, and find that although
individual valleys have non-trivial Chern numbers, the spectrum as a whole is
not gapped, so that the system is not a topological insulator.Comment: 9 pages. 9 figures include
TV News Story Segmentation Based on Semantic Coherence and Content Similarity
In this paper, we introduce and evaluate two novel approaches, one using video stream and the other using close-caption text stream, for segmenting TV news into stories. The segmentation of the video stream into stories is achieved by detecting anchor person shots and the text stream is segmented into stories using a Latent Dirichlet Allocation (LDA) based approach. The benefit of the proposed LDA based approach is that along with the story segmentation it also provides the topic distribution associated with each segment. We evaluated our techniques on the TRECVid 2003 benchmark database and found that though the individual systems give comparable results, a combination of the outputs of the two systems gives a significant improvement over the performance of the individual systems
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