A Positive Theory of Economic Growth and the Distribution of Income

This paper is a positive theory of the distribution of income and the growth rate of the economy. It builds on our earlier work (Meltzer and Richard, 1981) on the size of government. How does the distribution of income change as an economy grows? To answer this question we build a model of a labor economy in which consumers have diverse productivity. The government imposes a linear income tax which funds equal per capita redistribution. The tax rate is set in a sequence of single issue election in which the median productivity individual is decisive. Economic growth is the result of using a learning by doing technology, so higher taxes discourage labor causing the growth rate of the economy to fall. The distribution of productivity can widen due to an exogenous increase in technological specialization. This causes voters to raise the equilibrium tax rate and reduce growth. The distribution of pre-tax income widens. We calibrate the model using data from the U.S., U.K. and France. The results of the calibration show that the model is consistent with the facts about changes in income distribution over time in developed countries

Can Democracies Cooperate with China on AI Research? Rebalancing AI Research Networks

China looms large in the global landscape of artificial intelligence (AI) research, development, and policymaking. Its talent, growing technological skill and innovation, and national investment in science and technology have made it a leader in AI.This working paper considers whether and to what extent international collaboration with China on AI can endure. In Part I, it presents the history of China's AI development and extraordinarily successful engagement with international research and development (R&D) and explains how this history has helped China become a global leader in the field. Part II shows how China has become embedded in international AI R&D networks, with China and the United States becoming each other's largest collaborator and China also a major collaborator with each of the other six countries participating in FCAI. Part III then provides an overview of the economic, ethical, and strategic issues that call into question whether such levels of collaboration on AI can continue, as well as the challenges and disadvantages of disconnecting the channels of collaboration. The analysis then looks at how engagement with China on AI R&D might evolve

Local Field effects on the radiative lifetime of emitters in surrounding media: virtual- or real-cavity model?

For emitters embedded in media of various refractive indices, different macroscopic or microscopic theoretical models predict different dependencies of the spontaneous emission lifetime on refractive index. Among those models are the two most promising models: the virtual-cavity model and the real-cavity model. It is a priori not clear which model is more relevant for a given situation. By close analysis of the available experimental results and examining the assumptions underlying the two models, we reach a consistent interpretation of the experimental results and give the criteria which model should apply for a given situation.Comment: 12 pages with 4 figure

Randomized, Cross-Over Evaluation of Mobile Phone vs Paper Diary in Subjects with Mild to Moderate Persistent Asthma

Diaries are frequently used to evaluate therapy. Forgetfulness, however, can lead to missed entries. With paper diaries, these missing entries can be backfilled, compromising the reasons for using a diary. Electronic diaries are a potential means of mitigating this limitation. The pilot study was conducted to evaluate use of a mobile phone diary. Twelve subjects with mild persistent asthma were randomly assigned to mobile or paper diary for 2 weeks and then crossed over to use the other diary type for next 2 weeks. Of the 12 subjects, 7 preferred the mobile diary. However, the mean prevalence of missing data was greater when using the mobile (18% ± 9%) compared to paper diary (9% ± 4%; P = 0.05). In conclusion, the mobile diary was preferred by slightly more subjects. The greater prevalence of missing data when using this diary most likely results from the inability to backfill missing entries

The Radio Afterglow and the Host Galaxy of the X-Ray Rich GRB 981226

We report the discovery of a radio transient VLA 232937.2-235553, coincident with the proposed X-ray afterglow for the gamma-ray burst GRB 981226. This GRB has the highest ratio of X-ray to gamma-ray fluence of all the GRBs detected by BeppoSAX so far and yet no corresponding optical transient was detected. The radio light curve of VLA 232937.2-235553 is qualitatively similar to that of several other radio afterglows. At the sub-arcsecond position provided by the radio detection, optical imaging reveals an extended R=24.9 mag object, which we identify as the host galaxy of GRB 981226. Afterglow models which invoke a jet-like geometry for the outflow or require an ambient medium with a radial density dependence, such as that produced by a wind from a massive star, are both consistent with the radio data. Furthermore, we show that the observed properties of the radio afterglow can explain the absence of an optical transient without the need for large extinction local to the GRB.Comment: Accepted for publication in the Astrophysical Journal Letters. Thirteen pages. Three Postscript figure