Monopoly, employment and wages

This paper shows that monopoly in the capital equipment market results in higher productivity and wages but lower employment in comparison with the benchmark of competition. The combined effect on workers' welfare is negative, for expected earnings (defined as the product of the probability of employment and the wage earned when employed) are lowered. Indeed, low skill workers suffer relatively greater declines in employment and expected earnings. Furthermore, the employment and expected earnings of all workers, as well as the employment of low skill workers relative to high skill workers, are all decreasing in the relative supply of high skill workers. © 2002 Elsevier Science B.V. All rights reserved.postprin

New product introduction with costly search

In the usual model of product market search, a low search cost can turn out to have detrimental incentives on new product introduction as the low search cost erodes firms' market power, attenuating the profit from innovation. This paper studies a model of monopolistic competition with costly search, where the point of departure is that of a fixed cost of initiating search. In this environment, a low search cost could turn out to be favorable to innovation. At a low search cost, more consumers may decide to start searching, possibly resulting in higher profits for firms in the larger market, despite the erosion of market power. © 2005 Elsevier B.V. All rights reserved.postprin

Diffusion with variable production lead times

When there is not one obvious candidate technology, entrants to a new industry face a non-trivial choice between longer lead times in the setting up of production and a better chance that the technology could successfully deliver. This paper shows how this tradeoff may yield gradual diffusion. Diffusion is more protracted in industries where learning opportunities are more bountiful. The equilibrium minimizes the long-run equilibrium price, just as in the standard Marshallian model of a competitive industry. The market structure does not seem to affect the rate of diffusion with the monopoly choosing the same rate of diffusion that prevails in competition despite restricting output. © 2008 Springer-Verlag.postprin

Investors in Housing Market Search

We add specialist investors–agents who attempt to profit from buying low and selling high–to a canonical housing market search model. These agents facilitate the turnover of mismatched houses on behalf of end-users and they may survive even if they face an arbitrarily large cost of financing vis-a-vis ordinary households. Multiple equilibrium may exist. In one equilibrium, the participation of investors is extensive, resulting in rapid turnover, a high vacancy rate, and high housing prices. In another equilibrium, few houses are bought and sold by investors. Turnover is sluggish, few houses are vacant, and prices are moderate. A decline in the rate at which investors finance investment, can rather paradoxically, lower investors participation and housing prices in equilibrium.postprin

Flippers in housing market search

Session - HousingWe add flippers-specialist investors who attempt to profit from buying low and selling high to a canonical housing market search model. These agents facilitate the turnover of mismatched houses on behalf of end-users and they may survive even if they face an arbitrarily large cost of financing vis-a-vis ordinary households. Multiple equilibrium may exist. In one equilibrium, most, if not all, transactions are intermediated by flippers, resulting in rapid turnover, a high vacancy rate, and high housing prices. In another equilibrium, few houses are bought and sold by these agents. Turnover is sluggish, few houses are vacant, and prices are moderate. When flippers face a lower cost of financing, their presence can, rather unexpectedly, decline. There may then be lower, not higher, housing prices to follow an interest rate decline.postprin

Increasing wealth and increasing instability: The role of collateral

In development economics, growth in credit is generally associated with faster long-run growth as financial intermediation improves the efficiency of channeling capital to productive investment. Yet, among developing countries high growth in credit almost always guarantees the outbreak of a financial crisis. The authors attempt to reconcile the two seemingly contradictory facts with an endogenous growth model in which entry to international borrowing entails some significant fixed cost. The poorest countries are excluded from international borrowing because of the fixed cost. The higher-income developing countries will find it optimal to sink the fixed cost to borrow internationally, growing faster as a result, but also become prone to fluctuations arising from shocks to the international financial market.preprin

Estimating the commuting cost and commuting time property price gradients

In this paper, we estimate the property price gradients in Hong Kong. We distinguish our effort from previous studies on the subject by directly measuring the economic distance, i.e., the monetary commuting cost and commuting time, instead of merely the physical distance. Our results are generally supportive of the prediction of a negative property price gradient. In one specification, the estimated capitalization of the savings of commuting cost in property prices appears to be just right. The expected negative effect of commuting time on property values, however, can only be detected among observations with larger commuting times. Nevertheless, over the range where the effect of commuting time has the expected negative sign, the values of time implied by the estimates agree well with the results reported in the transportation economics literature. © 2003 Elsevier B.V. All rights reserved.preprin

Clinical Potentials of Cardiomyocytes Derived from Patient-Specific Induced Pluripotent Stem Cells

The lack of appropriate human cardiomyocyte-based experimental platform has largely hindered the study of cardiac diseases and the development of therapeutic strategies. To date, somatic cells isolated from human subjects can be reprogramed into induced pluripotent stem cells (iPSCs) and subsequently differentiated into functional cardiomyocytes. This powerful reprogramming technology provides a novel in vitro human cell-based platform for the study of human hereditary cardiac disorders. The clinical potential of using iPSCs derived from patients with inherited cardiac disorders for therapeutic studies have been increasingly highlighted. In this review, the standard procedures for generating patient-specific iPSCs and the latest commonly used cardiac differentiation protocols will be outlined. Furthermore, the progress and limitations of current applications of iPSCs and iPSCs-derived cardiomyocytes in cell replacement therapy, disease modeling, drug-testing and toxicology studies will be discussed in detail.published_or_final_versio

The spatial origin of commerce

Although dispersion raises productivity by relieving crowding, concentration promotes trade. The participation of specialist middlemen, who tend to cluster around the regional center, in the trading process would mitigate such tensions, for it becomes less urgent for others to scramble for central locations then from the increase in the density of economic activities around such locations. A city, populated by a cluster of middlemen, that serves as a platform for intermediate trade among producers in surrounding areas can exist without any increasing returns in production, transportation, and exchange. Indirect trade and pure commerce may, thus, have a spatial origin. © (2011) by the Economics Department of the University of Pennsylvania and the Osaka University Institute of Social and Economic Research Association.preprin

Early diagnosis of primary human herpesvirus 6 infection in childhood: Serology, polymerase chain reaction, and virus load

Qualitative and quantitative polymerase chain reaction (PCR) for human herpesvirus 6 (HHV-6) DNA in whole blood and plasma was correlated with serology and clinical assessment in 143 children hospitalized for undifferentiated febrile illness to evaluate options for diagnosis of primary HHV-6 infection on the acute blood specimen. PCR and serology for HHV-7 were done in parallel to define serologic cross-reactions. Using HHV-6 seroconversion as the reference standard, detection of HHV-6 DNA in whole blood in the absence of antibody in the plasma was the most reliable evidence of primary HHV-6 infection. Detection of HHV-6 DNA in plasma and a high virus load in whole blood (>3.3 log 10 copies/5 μL) had a sensitivity of 90% and 100%, respectively, in diagnosing primary HHV-6 infection. However, both were occasionally found in patients with other infections, possibly associated with HHV-6 reactivation. Maternal antibody may confound interpretation of serology in patients under 3 months of age.published_or_final_versio