Entry, Exit, and the Determinants of Market Structure

This paper estimates a dynamic, structural model of entry and exit in an oligopolistic industry and uses it to quantify the determinants of market structure and long-run firm values for two U.S. service industries, dentists and chiropractors. Entry costs faced by potential entrants, fixed costs faced by incumbent producers, and the toughness of short-run price competition are all found to be important determinants of long-run firm values, firm turnover, and market structure. Estimates for the dentist industry allow the entry cost to differ for geographic markets that were designated as Health Professional Shortage Areas and in which entry was subsidized. The estimated mean entry cost is 11 percent lower in these markets. Using simulations, we compare entry-cost versus fixed-cost subsidies and find that entry-cost subsidies are less expensive per additional firm

The JCMT Gould Belt Survey: A First Look at the Auriga–California Molecular Cloud with SCUBA-2

We present 850 and 450 μm observations of the dense regions within the Auriga–California molecular cloud using SCUBA-2 as part of the JCMT Gould Belt Legacy Survey to identify candidate protostellar objects, measure the masses of their circumstellar material (disk and envelope), and compare the star formation to that in the Orion A molecular cloud. We identify 59 candidate protostars based on the presence of compact submillimeter emission, complementing these observations with existing Herschel/SPIRE maps. Of our candidate protostars, 24 are associated with young stellar objects (YSOs) in the Spitzer and Herschel/PACS catalogs of 166 and 60 YSOs, respectively (177 unique), confirming their protostellar nature. The remaining 35 candidate protostars are in regions, particularly around LkHα 101, where the background cloud emission is too bright to verify or rule out the presence of the compact 70 μm emission that is expected for a protostellar source. We keep these candidate protostars in our sample but note that they may indeed be prestellar in nature. Our observations are sensitive to the high end of the mass distribution in Auriga–Cal. We find that the disparity between the richness of infrared star-forming objects in Orion A and the sparsity in Auriga–Cal extends to the submillimeter, suggesting that the relative star formation rates have not varied over the Class II lifetime and that Auriga–Cal will maintain a lower star formation efficiency

Economic Growth and the Diffusion of Clean Technologies: Explaining Environmental Kuznets Curves

Production often causes pollution as a by-product. Once environmental degradation becomes too severe, regulation is introduced by which society forces the economy to make a transition to cleaner production processes. We model this transition as a change in general purpose technology" and investigate how it interferes with economic growth driven by quality-improvements. The model gives an explanation for the inverted U-shaped pollution-income relation found in empirical research for many pollutants (Environmental Kuznets Curve). We provide an analytical foundation for the claim that the rise and decline of pollution can be explained by policy-induced technology shifts and intrasectoral changes

Industry dynamics, technological regimes and the role of demand

In this paper, we propose an industrial dynamics model to analyze the interactions between the price-performance sensitivity of demand, the sources of innovation in a sector, and certain features of the corresponding pattern of industrial transformation. More precisely, we study market concentration in different technological regimes and demand conditions. The computational analysis of our model shows that market demand plays a key role in industrial dynamics. Thus, although for intermediate values of the price-performance sensitivity, our results show the well-known relationships in the literature between technological regimes and industry transformation, we find surprising outcomes when demand is strongly biased either towards price or performance. Hence, for different technological regimes, a high performance sensitivity of demand tends to concentrate the market. On the other hand, under conditions of high price sensitivity, the industry generally tends to atomize. That is to say, for extreme values of the price-performance sensitivity of demand, we find concentrated or atomized market structures no matter the technological regime we are in. These results highlight the importance of considering the role of demand in the analysis of industrial dynamics

Cyclin-Dependent Kinase Activity Controls the Onset of the HCMV Lytic Cycle

The onset of human cytomegalovirus (HCMV) lytic infection is strictly synchronized with the host cell cycle. Infected G0/G1 cells support viral immediate early (IE) gene expression and proceed to the G1/S boundary where they finally arrest. In contrast, S/G2 cells can be infected but effectively block IE gene expression and this inhibition is not relieved until host cells have divided and reentered G1. During latent infection IE gene expression is also inhibited, and for reactivation to occur this block to IE gene expression must be overcome. It is only poorly understood which viral and/or cellular activities maintain the block to cell cycle or latency-associated viral IE gene repression and whether the two mechanisms may be linked. Here, we show that the block to IE gene expression during S and G2 phase can be overcome by both genotoxic stress and chemical inhibitors of cellular DNA replication, pointing to the involvement of checkpoint-dependent signaling pathways in controlling IE gene repression. Checkpoint-dependent rescue of IE expression strictly requires p53 and in the absence of checkpoint activation is mimicked by proteasomal inhibition in a p53 dependent manner. Requirement for the cyclin dependent kinase (CDK) inhibitor p21 downstream of p53 suggests a pivotal role for CDKs in controlling IE gene repression in S/G2 and treatment of S/G2 cells with the CDK inhibitor roscovitine alleviates IE repression independently of p53. Importantly, CDK inhibiton also overcomes the block to IE expression during quiescent infection of NTera2 (NT2) cells. Thus, a timely block to CDK activity not only secures phase specificity of the cell cycle dependent HCMV IE gene expression program, but in addition plays a hitherto unrecognized role in preventing the establishment of a latent-like state