The Impact of the Kansas Wheat Breeding Program on Wheat Yields, 1911–2006

This paper quantifies advances of the Kansas Agricultural Experiment Station (KAES) wheat breeding program for two time periods: (1) 1911 to 2006 and (2) 1977 to 2006. Using multiple regression, increases in yields of wheat varieties grown in Kansas are quantified, holding growing conditions and other improvements in productivity constant. Differences in KAES variety yields and those released by other public and private breeders are quantified. During the ‘‘new age’’ of wheat breeding (1977–2006), wheat breeding alone is found to have increased yields by 6.182 bushels per acre, or an average increase of 0.206 bushels per year.wheat yield, public wheat breeding, multiplicative heteroscedasticity, economic impact of technological change, Agribusiness, Farm Management, O13, Q16,

Resistive flow in a weakly interacting Bose-Einstein condensate

We report the direct observation of resistive flow through a weak link in a weakly interacting atomic Bose-Einstein condensate. Two weak links separate our ring-shaped superfluid atomtronic circuit into two distinct regions, a source and a drain. Motion of these weak links allows for creation of controlled flow between the source and the drain. At a critical value of the weak link velocity, we observe a transition from superfluid flow to superfluid plus resistive flow. Working in the hydrodynamic limit, we observe a conductivity that is 4 orders of magnitude larger than previously reported conductivities for a Bose-Einstein condensate with a tunnel junction. Good agreement with zero-temperature Gross-Pitaevskii simulations and a phenomenological model based on phase slips indicate that the creation of excitations plays an important role in the resulting conductivity. Our measurements of resistive flow elucidate the microscopic origin of the dissipation and pave the way for more complex atomtronic devices.Comment: Version published in PR

Reflexive and Selective Competitive Behaviors—Inertia, Imitation, and Interfirm Rivalry

Competitive dynamics research has established the important impact that the level of firm competitive activity has on rival response and firm performance. Less understood, however, are inputs that influence firm activity, specifically, the extent to which firms reflexively repeat prior activity versus selectively taking actions. Drawing from the awareness–motivation–capability framework, we develop and test theory that firm decision makers are not only predisposed to behave reflexively, but are also influenced by contextual factors, suggesting cognitive selection. Utilizing a longitudinal sample of marketing activity of 58 firms and 2,164 firm–rival dyads in 11 industries, we find that firms undertake both reflexive and selective competitive processes. Positive effects of prior levels of activity are moderated by the firm’s own prior performance, as well as the rivals’ similarity and industry standing

NK cells and cancer: you can teach innate cells new tricks

Abstract | Natural killer (NK) cells are the prototype innate lymphoid cells endowed with potent cytolytic function that provide host defence against microbial infection and tumours. Here, we review evidence for the role of NK cells in immune surveillance against cancer and highlight new therapeutic approaches for targeting NK cells in the treatment of cancer