Continuous-time mean-variance portfolio optimization in a jump-diffusion market

In this paper, we take up an approach of (Lindberg, in Bernoulli, 15(2):464–474, 2009) who introduced a new parameterization of the Black–Scholes model that allows for an easy solution of the continuous-time Markowitz mean-variance problem. We generalize the results of (Lindberg, in Bernoulli, 15(2):464–474, 2009) to a jump-diffusion market setting and slightly correct the proof and the assertion of the main result. Further, we demonstrate the implications of the Lindberg parameterization for the stock price drift vector in different market settings, analyse the dependence of the optimal portfolio from jump and diffusion risk and finally indicate how to use the method. We particularly also show how the optimal strategy can be obtained with the restricted use of historical data.     

Learning-by-doing versus Schooling in a Model of Endogenous Growth

A two sector model of learning-by-doing measured by means of production aggregated over time and of human capital accumulation in a schooling sector is presented. Time utilization is rival between schooling and learning-by-doing. Depending on the sum of elasticities of the accumulated factors (i.e., of production experience and educational human capital) in both sectors, a situation with or without endogenous growth results. Dynamic optimization of the choice between leisure and working and of the division of human capital between education and production is executed. Transitional dynamics are analyzed for a Cobb-Douglas example and a numerical simulation is performed.JEL classification: C61, D90, O41.Acknowledgements The author would like to thank Eric C. Meyer and two anonymous referees for helpful comments. The usual caveats apply.revised version received November 23, 2003     

Structuring of temporary multi‐organizations: Contingency theory in the building sector

The appropriate management of construction projects presupposes a clear comprehension of the structure of the temporary multi‐organization (TMO); however, most of the work on the structuring of TMOs has concentrated either on procurement strategies or the structure of individual organizations. Current approaches, therefore, do not fully consider the roles of all project stakeholders, the informal communications, and the complexity of the client organization. Instead, we argue that the contingency theory contributes to the understanding of the structuring of TMOs. The analysis of 27 recent construction projects allows us to identify two contingency factors and patterns of configuration of the TMO.     

Entrepreneurship: Cause and Consequence of Financial Optimism

Extant evidence that the self‐employed overestimate their returns by a greater margin than employees is consistent with two mutually inclusive possibilities. Self‐employment may foster optimism or intrinsic optimists may be drawn to self‐employment. Previous research is generally unable to disentangle these effects because of reliance on cross‐sectional data. Using longitudinal data, this paper finds that employees who will be self‐employed in the future overestimate their short‐term financial wellbeing by more than those who never become self‐employed. Optimism is higher still when self‐employed. These results suggest that the greater optimism of the self‐employed reflects both psychological disposition and environmental factors. By providing greater scope for optimism, self‐employment entices the intrinsically optimistic.     

Modelling innovation support systems for regional development – analysis of cluster structures in innovation in Portugal

The present article offers a concise theoretical conceptualization and operational analysis of the contribution of innovation to regional development. The latter concepts are closely related to geographical proximity, knowledge diffusion and filters and clustering. Institutional innovation profiles and regional patterns of innovation are two mutually linked, novel conceptual elements in this article. Next to a theoretical framing, the article employs the regional innovation systems concept as a vehicle to analyse institutional innovation profiles. Our case study addresses three Portuguese regions and their institutions, included in a web-based inventory of innovation agencies which offered the foundation for an extensive database. This data-set was analysed by means of a recently developed principal coordinates analysis followed by a Logistic Biplot approach (leading to a Voronoi mapping) to design a systemic typology of innovation structures where each institution is individually represented. There appears to be a significant difference in the regional innovation patterns resulting from the diverse institutional innovation profiles concerned. These profiles appear to be region specific. Our conclusion highlights the main advantages in the use of the method used for policy-makers and business companies.     

Ramsey policies in a small open economy with sticky prices and capital

This paper analyzes jointly optimal fiscal and monetary policies in a small open economy with capital and sticky prices. We allow for trade in consumption goods under perfect international risk-sharing. We consider balanced-budget fiscal policies where authorities use distortionary taxes on labor and capital together with monetary policy using the nominal interest rate. First, as long as a symmetric equilibrium is considered, the steady state in an open economy is isomorphic to that of a closed economy. Second, sticky prices’ allocations are almost indistinguishable from flexible prices allocations both in open and closed economies. Third, the open economy dimension delivers results that are qualitatively similar to those of a closed economy but with significant quantitative changes. Tax rates are both more volatile and more persistent to undo the distortions implied by terms of trade fluctuations.     

Vertical integration as a remedy for imbalances in the ‘Porterian’ value system. The Dutch financial securities industry at the beginning of the 20th century

The way of accounting for vertical integration, of this paper is based on the ‘Porterian’ value system and focuses on the relation between the creation and appropriation of value. The essence of a value system is that at each stage in the system value is created and added to the value created at previous stages. We propose that firms which are unable to appropriate the value they create at the stage they currently inhabit, would find it advantageous to integrate vertically towards stages offering a more attractive relation between value appropriation and value creation. This argument will be illustrated here by the case of a large Dutch bank that integrated vertically towards securities trading.     

Planting flexibility: Implications for agricultural sustainability

There is a general belief that federal commodity programs restrict adoption of more sustainable production systems. In the 1990 farm legislation, Congress introduced limited planting flexibility to address these concerns and to reduce federal farm program costs. This program estimates the impact of planting flexibility on selected agricultural sustainability indicators and its policy implications. Results show that planting flexibility is a necessary but not sufficient condition for implementing more sustainable production systems. Other factors such as the availability of economically viable alternatives, macroeconomic conditions, and local resource and environmental concerns need to be considered. Policy reforms can help in achieving economic and environmental gains only in locations with economically viable alternatives. In other cases, increased research and development of new systems are needed to achieve desired results.     

An Introduction to the Patstat Database with Example Queries

This article provides an introduction to the Patstat patent database. It offers guided examples of 10 popular queries that are relevant for research purposes and that cover the most important data tables. It is targeted at academic researchers and practitioners who are willing to learn the basics of the database.     

The effect of fertility on labour force participation: The Spanish evidence

Abstract. The aim of this paper is to estimate the effect of fertility on the decision of labour force participation of married females in Spain, allowing for the existence of unobserved characteristics that affect both fertility and participation. We use a pooling of five waves of the European Household Panel for Spain (1994–1998). Results indicate that not taking into account the unobserved characteristics that affect both variables imposes on average a strong downward bias on the true effect of fertility on participation. This bias is especially strong for highly educated females. We are grateful to Raquel Carrasco and an anonymous referee for helpful comments. Financial support from Gobierno Vasco (PI-1999-160)), Ministry of Education and Science (BE2000-1394), Instituto de la Mujer and Universidad del País Vasco (UPV 00035.321-13511/2001) is gratefully acknowledged.