In defense of science—What would John do?

Recent onslaughts on the importance of pure research to our collective well-being are trending. In this essay, I discuss the issues involved and offer a rebuttal. The thoughts are inspired by my mentor, academic sibling, and idol John Leask Lumley

Academic Malaise: Bring Back the Groves of Academe

The state of university governance and academic freedom are discussed. Several related topics are also considered: tuition inflation; term versus tenure-track faculty; massive open online courses; and relative standing of higher education in the United States

A Comparative Estimation of Financial Frictions in Japan and Korea

We apply the Business Cycle Accounting method a la Chari, Kehoe, and McGrattan (2007) to the Japanese and the Korean economy and quantitatively analyze the effects of financial frictions during the recent recessions. First, we compute exogenous distor- tions in the financial, government purchases, labor, and production markets. The preliminary results show that the sudden drop in production efficiency (TFP) was the main reason of the Korean recession while the increase in labor market distortions was the main reason of the Japanese slump. Next, we orthogonalize the innovations to the distortions and quantify the maximum spill-over effects of financial frictions on output fluctuations in both countries following Christiano and Davis (2006). Our results imply that financial frictions may have been important in explaining the recessions in both countries through their effects on TFP and labor market distortions

Far-infrared and accretion luminosities of the present-day active galactic nuclei

We investigate the relation between star formation (SF) and black hole accretion luminosities, using a sample of 492 type-2 active galactic nuclei (AGNs) at z < 0.22, which are detected in the far-infrared (FIR) surveys with AKARI and Herschel. We adopt FIR luminosities at 90 and 100 um as SF luminosities, assuming the proposed linear proportionality of star formation rate with FIR luminosities. By estimating AGN luminosities from [OIII]5007 and [OI]6300 emission lines, we find a positive linear trend between FIR and AGN luminosities over a wide dynamical range. This result appears to be inconsistent with the recent reports that low-luminosity AGNs show essentially no correlation between FIR and X-ray luminosities, while the discrepancy is likely due to the Malmquist and sample selection biases. By analyzing the spectral energy distribution, we find that pure-AGN candidates, of which FIR radiation is thought to be AGN-dominated, show significantly low-SF activities. These AGNs hosted by low-SF galaxies are rare in our sample (~ 1%). However, the low fraction of low-SF AGN is possibly due to observational limitations since the recent FIR surveys are insufficient to examine the population of high-luminosity AGNs hosted by low-SF galaxies.Comment: Accepted for publication in ApJ, 13 pages, 9 figure

Learning from Neighbors about a Changing State

Agents learn about a changing state using private signals and past actions of neighbors in a network. We characterize equilibrium learning and social influence in this setting. We then examine when agents can aggregate information well, responding quickly to recent changes. A key sufficient condition for good aggregation is that each individual's neighbors have sufficiently different types of private information. In contrast, when signals are homogeneous, aggregation is suboptimal on any network. We also examine behavioral versions of the model, and show that achieving good aggregation requires a sophisticated understanding of correlations in neighbors' actions. The model provides a Bayesian foundation for a tractable learning dynamic in networks, closely related to the DeGroot model, and offers new tools for counterfactual and welfare analyses.Comment: minor revision tweaking exposition relative to v5 - which added new Section 3.2.2, new Theorem 2, new Section 7.1, many local revision