R&D and Non-Linear Productivity Growth of Heterogeneous Firms

The present paper studies the relationship between R&D investment and firm productivity growth by explicitly accounting for non-linearities in the R&D-productivity relationship and inter-sectoral firm heterogeneity. In order to address these issues, we employ a two step estimation approach, and match two firm-level panel data sets for the OECD countries, which allows us to relax both the linearity and homogeneity assumptions of the canonical Griliches (1979) knowledge capital model. Our results suggest that: (i) R&D investment increases firm productivity with an average elasticity of 0.15; (ii) the impact of R&D investment on firm productivity is differential at different levels of R&D intensity - the productivity elasticity ranges from -0.02 for low levels of R&D intensity to 0.33 for high levels of R&D intensity; (iii) the relationship between R&D expenditures and productivity growth is non-linear, and only after a certain critical mass of R&D is reached, the productivity growth is significantly positive;(iv) there are important inter-sectoral differences with respect to R&D investment and firm productivity - high-tech sectors' firms not only invest more in R&D, but also achieve more in tfirms of productivity gains connected with research activities

The Effect of Credit Conditions on the Dutch Housing Market

It is widely perceived that the supply of mortgages, especially since the extensive liberalization of the mortgage market since the 1980s, has had implications for the Dutch housing market. In this paper we introduce a new method to estimate a credit condition index (CCI). The credit conditions index represents changes in the supply of credit over time, apart from changes in interest rates and income. Examples of these changes include (1) the development of markets for financial futures, options, swaps, securitized loans and synthetic securities which allowed for easy access to credit for financial intermediaries, (2) more sophisticated risk management, for example improved initial credit scoring, (3) changes in risk-perception by financial intermediaries due to changes in the macro-economic environment, like rate of unemployment, (4) introduction of new mortgage products, (5) reduced transaction costs and asymmetric information with innovations of IT, telephony and data management and (6) financial liberation. Financial liberation is the relaxation or tightening of credit controls like liquidity ratios on banks, down-payment requirements, maximum repayment periods, allowed types of mortgages, loan-to-value and loan-to-income ratios, etc. The credit conditions index is estimated as an unobserved component in an error-correction model in which the average amount of mortgage is explained by the borrowing capacity and additional control variables. The model is estimated on data representing first time buyers. For first time buyers we can assume that the housing and non-housing wealth is essentially zero. The credit condition index is subsequently used in an error-correction model for house prices representing not only first time buyers, but all households. The models are estimated using quarterly data from 1995 to 2012. The estimated credit condition index has a high correlation with the Bank Lending Survey, a quarterly survey in which banks are asked whether there is a tightening or relaxation of (mortgage) lending standards compared to the preceding period. The credit condition index has explanatory power in the error-correction model for housing prices. In real terms house prices declined about 25% from 2009 to 2012. The estimation results show that 12% point of this decline can be attributed to a decline in the credit conditions index

Genetic Monitoring Reveals Genetic Stability within and among Threatened Chinook Salmon Populations in the Salmon River, Idaho

Identifying and understanding temporal genetic changes within fish populations is important for the management of these populations, especially those of conservation concern. Such changes are often the result of genetic drift, which can be exacerbated when the size of a population decreases. Using molecular-genetics techniques, we monitored nine populations of Chinook salmon Oncorhynchus tshawytscha in the Salmon River, Idaho, to determine how the genetic characteristics within and among these populations have changed over time. We found no evidence of change in the level of heterozygosity or allelic richness over three to four generations in eight of the populations. This is probably due to the fact that the populations all maintained a sufficiently large effective size, even though a few of the populations did show a decline in effective size. Also, the genetic structure among the populations did not change appreciably over time. Populations that had been supplemented with hatchery-reared fish showed genetic similarity to the within-basin hatchery source population, presumably because of the extensive use of native fish for hatchery brood stocks and minimal out-of-basin stock transfers. The lack of a detectable decline in these populations’ levels of genetic diversity is encouraging, given the species’ threatened status under the U.S. Endangered Species Act

Correction: Demographic history shaped geographical patterns of deleterious mutation load in a broadly distributed Pacific Salmon.

[This corrects the article DOI: 10.1371/journal.pgen.1008348.]

Demographic history shaped geographical patterns of deleterious mutation load in a broadly distributed Pacific Salmon.

A thorough reconstruction of historical processes is essential for a comprehensive understanding of the mechanisms shaping patterns of genetic diversity. Indeed, past and current conditions influencing effective population size have important evolutionary implications for the efficacy of selection, increased accumulation of deleterious mutations, and loss of adaptive potential. Here, we gather extensive genome-wide data that represent the extant diversity of the Coho salmon (Oncorhynchus kisutch) to address two objectives. We demonstrate that a single glacial refugium is the source of most of the present-day genetic diversity, with detectable inputs from a putative secondary micro-refugium. We found statistical support for a scenario whereby ancestral populations located south of the ice sheets expanded recently, swamping out most of the diversity from other putative micro-refugia. Demographic inferences revealed that genetic diversity was also affected by linked selection in large parts of the genome. Moreover, we demonstrate that the recent demographic history of this species generated regional differences in the load of deleterious mutations among populations, a finding that mirrors recent results from human populations and provides increased support for models of expansion load. We propose that insights from these historical inferences should be better integrated in conservation planning of wild organisms, which currently focuses largely on neutral genetic diversity and local adaptation, with the role of potentially maladaptive variation being generally ignored