A comprehensive review on the chemistry of Spongia sp. is here presented, together with the biological activity of the isolated compounds. The compounds are grouped in sesquiterpene quinones, diterpenes, C21 and other linear furanoterpenes, sesterterpenes, sterols (including secosterols), macrolides and miscellaneous compounds. Among other reports we include studies on the intraspecific diversi...

Inspired by the theory of variety-expanding product innovation we derive a testable relationship of outsourcing on the growth rate of knowledge. We estimate this relationship with a firm-level dataset, which is a unique match of PATSTAT patent data and the Amadeus dataset. We find evidence that forward spillovers are stronger than backward spillovers, where forward spillovers are defined as spi...

This paper provides preliminary evidence that interest groups reduce both the level and the volatility of returns on a national stock market. These findings are robust to model specifications that include traditional growth regression “policy” variables as well as political, economic, and financial institutions variables. The estimated magnitude of the relationship between interest group activi...

Nonlinear regression with measurement error is important for estimation from microeconomic data. One approach to identification and estimation is a causal model, where the unobserved true variable is predicted by observable variables. This paper is about estimation of such a model using simulated moments and a flexible disturbance distribution. An estimator of the asymptotic variance is given f...

Despite widespread belief that membership in the World Trade Organization (WTO) improves the quality of governance, there is no convincing empirical evidence. Here, we investigate whether WTO membership has a causal effect on firm-level reports of political corruption using a nonparametric partial identification approach to bound the average treatment effect (ATE). We also analyze conditional A...

We implement an endogeneous switching-regression model for labour productivity and firms’ decision to use business–to–business (B2B) e–commerce. Our approach allows B2B usage to affect any parameter of the labour productivity equation and to properly take account of strategic complementarities between the input factors and B2B usage. Empirical evidence from 1,394 German firms shows that firms u...

A Martingale Representation for Matching Estimators Matching estimators are widely used in statistical data analysis. However, the distribution of matching estimators has been derived only for particular cases (Abadie and Imbens, 2006). This article establishes a martingale representation for matching estimators. This representation allows the use of martingale limit theorems to derive the asym...

The invariants of a pair of quadratic forms and a pair of coplanar conies are revisited following [1, 5, 2]. For a given pair of conies, with their associated matrices Ci and C2, we show that Trace(CjCi), Trac^C^ C2) and |Ci |/|C21 are only invariants of associated quadratic forms, but not invariants of the conies. Two of true invariants of the conies are Trace(C~Ci) |C->I . Trace<C~ C2) |C, I ...