The most widely commercially available bioresorbable scaffold (BRS) Absorb has strut thickness of 165 microns. Therefore, it has potential for higher thrombogenicity, especially in the early phase of vessel healing. As such, decreasing the BRS strut thickness with no adverse effect on its

Lack of quality seed and technical knowhow are considered major constraints to improving aquaculture productivity and profitability in Bangladesh. This paper assesses the outcomes of investments in improving carp seed quality and farmer training, targeting poor and women fish farmers, on the productivity and profitability of homestead aquaculture systems in Southwest Bangladesh. The paper also assesses the effect of factors such as stocking density, use of fertilizer and feed, farmers’ characteristics and location on fish yields and determines the major driving factors influencing adoption of improved practices. The results show that farmers who used improved carp seed and received training had higher yield and profit from homestead aquaculture than farmers who received training but did not use improved seed. Both of these farmer categories had higher homestead pond yields and profit than those who did not receive training but used improved seed and all three categories were found to have higher yield and profit than the control group. These results suggest that using improved seed without technical advice is unlikely to have a significant impact on aquaculture productivity and profitability while training without using improved quality seed is likely to have a positive impact on these outcomes. These results are supported by a multiple regression model which shows that, when controlling for other factors, farmers who had been trained and used improved seed were 52% more productive than the control group, while those who had been trained and did not use improved seed were 15% more productive. There was no significant difference (P<0.05) in productivity between farmers who had not received training but used improved quality seed and the control group. Location, stocking density, pond water area and experience were also found to significantly influence homestead pond productivity. The additional net return generated by farmers as a result of investments in improved seed and training is estimated to be approximately US$ 470,000 and US$ 210,000 for training alone, representing a return on investment (ROI) of 285% and 394% respectively. Despite the high ROI, the modest absolute increases in income and production estimated for participating households, due mostly to the low base from which growth is taking place, suggests the need for future investments to bring about relatively higher rates of productivity increases if they are to have meaningful impacts on household production and income. Overall, these results suggest that it is not enough for aquaculture development interventions to focus only on the technical fix of improved seed, rather capacity building of farmers is also crucial if aquaculture productivity and profitability are to be successfully improved. Statement of relevanceAll authors have approved the final version of the article and agreed to submit in the journal.

When the seller of an asset grants a right-of-first-refusal to a buyer, this special buyer has the opportunity to purchase the asset at the best price the seller can obtain from the other potential buyers. We show that the right-of-first-refusal is inefficient, and it benefits the special buyer at the expense of the seller and other buyers. In a private values model, the benefit the special buyer obtains via the right-of-first-refusal equals the cost to the seller. When buyers' valuations are correlated, the presence of a special buyer exacerbates the winner's curse on regular buyers. Consequently, the special buyer's expected gain from the right-of-first-refusal is often less than the expected loss to the seller. Thus, our analysis suggests that the seller should exercise considerable caution prior to deciding whether to grant this right to a buyer.

When the seller of an asset grants a right-of-first-refusal to a buyer, this special buyer has the opportunity to purchase the asset at the best price the seller can obtain from the other potential buyers. We show that the right-of-first-refusal is inefficient, and it benefits the special buyer at the expense of the seller and other buyers. In a private values model, the benefit the special buyer obtains via the right-of-first-refusal equals the cost to the seller. When buyers' valuations are correlated, the presence of a special buyer exacerbates the winner's curse on regular buyers. Consequently, the special buyer's expected gain from the right-of-first-refusal is often less than the expected loss to the seller. Thus, our analysis suggests that the seller should exercise considerable caution prior to deciding whether to grant this right to a buyer.

Modeling correlated default risk is a new phenomenon currently sweeping through the credit markets. In this paper, we develop a methodology to model, simulate and assess the joint default process of hundreds of issuers. Our study is based on a data set of default probabilities supplied by Moody's Risk Management Services. We undertake an empirical examination of the joint stochastic process of default risk over the period of 1987-2000 using copula functions. To determine the appropriate choice of the joint default process, we propose a new metric. This metric accounts for different aspects of default correlation, namely (i) level, (ii) asymmetry and (iii) tail-dependence and extreme behavior. Our model, based on estimating a joint system of over 600 issuers, is designed to replicate the empirical joint distribution of defaults. A comparison of a jump model and a regime-switching model shows that the latter provides a better representation of the properties of correlated default. We also find that the skewed double-exponential distribution is the best choice for the marginal distribution of each issuer's hazard rate process, and combines well with the normal, Gumbel, Clayton and student's t copulas in the joint dependence relationship amongst issuers. As a complement to the methodological innovation, we show that (a) appropriate choices of marginal distributions and copulas are essential in modeling correlated default, (b) accounting for regimes is an important aspect of joint specifications of default risk, and (c) misspecification of credit portfolio risk can occur easily if joint distributions are inappropriately chosen. The empirical evidence suggests that improvements are indeed possible over the standard Gaussian copula used in practice.

Using a comprehensive and unique data set from Moody's, we examine correlations between default risk for over 7,000 U.S. public firms. This is the first paper to empirically document the correlation structure both in the time-series and in the cross-section across almost all U.S. non-financial firms. We find that default probabilities of issuers vary over time, and are positively correlated. Moreover, the correlations across firms also vary over time systematically, in a manner that is related to an economy-wide level of default risk. Joint default risk increases as the default risk in the economy increases. Our results also suggest that the magnitude of joint default depends on the quality of issuers; highest quality issuers have higher default correlations than medium grade firms.