Technology Diffusion on the International Trade Network

Technological innovations generate knowledge spillovers-non-innovators benefit through the adoption, imitation, and extension of new technologies. International trade facilitates technology diffusion by providing importing countries access to technical knowledge that they can potentially internalize. Previous studies of the effect of trade on technology diffusion typically only consider the impact of direct (bilateral) trade on indirect measures of technology (e.g., total factor productivity). We contend that the analysis of trade's impact on technology diffusion would be more accurately assessed by using direct measures of specific technologies (e.g., intensity levels) and by allowing for the influence of both the direct and indirect effects of trade in the analysis. The latter is accomplished by modeling the international trade system as a weighted network, which quantifies both direct and indirect trade linkages. Combining trade data with data on the adoption of specific technologies, we find that the network effects of trade play a significant role in technology diffusion. In most cases, countries that are better-connected on the trade network have higher technology intensities. Further support for the importance of trade is provided by the finding that for "outdated" technologies, better-connected countries have lower technology intensities because of their adoption of newer, substitute technologies. © 2016 Wiley Periodicals, Inc

Global innovation races, offshoring and wage inequality

In the 1970s and 1980s the US position as the global technological leader was increasingly challenged by Japan and Europe. In those years the US skill premium and residual wage inequality increased substantially. This paper presents a two-region, quality-ladder growth model where the lagging economy progressively catches up with the leader. As the innovation gap closes, the advanced country experiences fiercer foreign technological competition that forces its firms to innovate more. Faster technical change increases the skill premium and residual inequality. Offshoring production and innovation plays a key role in shaping the link between international competition and inequality

Multiple Peptidoglycan Modification Networks Modulate Helicobacter pylori's Cell Shape, Motility, and Colonization Potential

Helical cell shape of the gastric pathogen Helicobacter pylori has been suggested to promote virulence through viscosity-dependent enhancement of swimming velocity. However, H. pylori csd1 mutants, which are curved but lack helical twist, show normal velocity in viscous polymer solutions and the reason for their deficiency in stomach colonization has remained unclear. Characterization of new rod shaped mutants identified Csd4, a DL-carboxypeptidase of peptidoglycan (PG) tripeptide monomers and Csd5, a putative scaffolding protein. Morphological and biochemical studies indicated Csd4 tripeptide cleavage and Csd1 crosslinking relaxation modify the PG sacculus through independent networks that coordinately generate helical shape. csd4 mutants show attenuation of stomach colonization, but no change in proinflammatory cytokine induction, despite four-fold higher levels of Nod1-agonist tripeptides in the PG sacculus. Motility analysis of similarly shaped mutants bearing distinct alterations in PG modifications revealed deficits associated with shape, but only in gel-like media and not viscous solutions. As gastric mucus displays viscoelastic gel-like properties, our results suggest enhanced penetration of the mucus barrier underlies the fitness advantage conferred by H. pylori's characteristic shape