The revival of the Baldwin Effect

The idea that a genetically fixed behavior evolved from the once differential learning ability of individuals that performed the behavior is known as the Baldwin effect. A highly influential paper [Hinton G.E., Nowlan S.J., 1987. How learning can guide evolution. Complex Syst. 1, 495-502] claimed that this effect can be observed in silico, but here we argue that what was actually shown is that the learning ability is easily selected for. Then we demonstrate the Baldwin effect to happen in the in silico scenario by estimating the probability and waiting times for the learned behavior to become innate. Depending on parameter values, we find that learning can increase the chance of fixation of the learned behavior by several orders of magnitude compared with the non-learning situation

Region's reputation and the price of regional products: a hedonic analysis of Portuguese quality cheese

Resources (tangible and intangible) can be mobilized to increase region's reputation and image giving a competitive advantage to certain products with origin in that region. The returns of a region's resources depend upon the ability of local firms to appropriate the rents earned and whether the consumers value the characteristics of the region that are associated with the product, being disposed to pay a price premium. The estimation of a hedonic price function, which relates the price of Portuguese regional cheeses to its various attributes provided empirical support to test the importance of designation of origin on price. The study showsthat some designations of origin and milk types have a significant impact on price, while retailer format (hypermarket versus online store)and cheese characteristics (cured versus not cured)are nor significant. Specifically, while cheeses from regions of Minho e Trás os Montes and Alentejo are expected to have price premiums, cheeses from regions of Beiras and Ilhas are expected to have discounts. Also, cheeses made with mixed milk and goat's and ewe's milk all have positive effects on price regarding cow's milk (base category).

Modelling spin waves in noncollinear antiferromagnets: spin-flop states, spin spirals, skyrmions and antiskyrmions

Spin waves in antiferromagnetic materials have great potential for next-generation magnonic technologies. However, their properties and their dependence on the type of ground-state antiferromagnetic structure are still open questions. Here, we investigate theoretically spin waves in one- and two-dimensional model systems with a focus on noncollinear antiferromagnetic textures such as spin spirals and skyrmions of opposite topological charges. We address in particular the nonreciprocal spin excitations recently measured in bulk antiferromagnet $\alpha$--$\text{Cu}_2\text{V}_2\text{O}_7$ utilizing inelastic neutron scattering experiments [Phys.\ Rev.\ Lett.\ \textbf{119}, 047201 (2017)], where we help to characterize the nature of the detected spin-wave modes. Furthermore, we discuss how the Dzyaloshinskii-Moriya interaction can lift the degeneracy of the spin-wave modes in antiferromagnets, resembling the electronic Rashba splitting. We consider the spin-wave excitations in antiferromagnetic spin-spiral and skyrmion systems and discuss the features of their inelastic scattering spectra. We demonstrate that antiskyrmions can be obtained with an isotropic Dzyaloshinskii-Moriya interaction in certain antiferromagnets.Comment: 26 pages, 9 figure

First-principles investigation of spin wave dispersions in surface-reconstructed Co thin films on W(110)

We computed spin wave dispersions of surface-reconstructed Co films on the W(110) surface in the adiabatic approximation. The magnetic exchange interactions are obtained via first-principles electronic structure calculations using the Korringa-Kohn-Rostoker Green function method. We analyze the strength and oscillatory behavior of the intralayer and interlayer magnetic interactions and investigate the resulting spin wave dispersions as a function of the thickness of Co films. In particular, we highlight and explain the strong impact of hybridization of the electronic states at the Co-W interface on the magnetic exchange interactions and on the spin wave dispersions. We compare our results to recent measurements based on electron energy loss spectroscopy [E. Michel, H. Ibach, and C.M. Schneider, Phys. Rev. B 92, 024407 (2015)]. Good overall agreement with experimental findings can be obtained by considering the possible overestimation of the spin splitting, stemming from the local spin density approximation, and adopting an appropriate correction.Comment: 14 pages, 14 figure

Portuguese quality wine and the region-of-origin effect: consumers' and retailers' perceptions

This study investigates the relative importance of region of origin associated with extrinsic (price, brand, promotion) and intrinsic (grape, type of wine, colour, age, special references) cues in the decisions of final consumers and small retailers to buy Portuguese quality wine. In order to attain this goal we conducted a survey through face-to-face interviews in the Minho region. The results show that the dominant factor of influence in the acquisition of wine is the region of origin, both for final consumers and small retailers. Despite its importance, brand was not the principal variable to influence consumers’ wine choice, while price has been regarded as a less important extrinsic quality cue. One interesting result is the type of wine (“maduro” or “verde”) which seems to be the most preferred intrinsic cue for final consumers and small retailers. The findings also indicate that the regions of Alentejo, Douro and Verde are clearly the leaders in terms of customer acceptance.