Spectral Analysis for Economic Time Series

The last ten years have witnessed an increasing interest of the econometrics community in spectral theory. In fact, decomposing the series evolution in periodic contributions allows a more insightful view of its structure and on its cyclical behavior at different time scales. In this paper I concisely broach the issues of cross-spectral analysis and filtering, dwelling in particular upon the windowed filter (Iacobucci and Noullez 2002). In order to show the usefulness of these tools, I present an application to real data, namely to US unemployment and inflation. I show how cross spectral analysis and filtering can be used to find correlation between them (i.e. the Phillips curve) in some specific frequency bands, even if it does not appear in raw data.spectral and cross spectral analysis, frequency selective filters, Phillips curve.

Business groups and the boundaries of the firm

This paper aims to show that the business group – i.e. the set of firms under common ownership and control – is the most appropriate unit to study the behavior and organization of firms and define their boundaries. Particular emphasis is given to notions such as unitary direction – i.e. the influence over strategic decisions – and administrative co-ordination which allow owners to exercise supervision and authority over the controlled companies.business group; boundary of the firm; unitary direction

The growth of business groups by habitual entrepreneurs: the role of entrepreneurial teams

Previous research demonstrates that entrepreneurial processes underpin the growth of business groups. A business group is a set of companies controlled by the same entrepreneur. Case studies of portfolio entrepreneurs suggest that one of the main reasons for business group formation is the need to create an entrepreneurial team, which is achieved by giving minority shares in the new ventures to others, mainly former employees. This enhances the portfolio entrepreneur’s ability to grow and diversify the businesses under their control. The paper identifies and discusses the different types of entrepreneurial teams developed by portfolio entrepreneurs, and their dynamics.Business groups, entrepreneurship, entrepreneurial teams

Diffractive phenomena

The most recent theoretical and experimental results in the field of diffractive scattering are reviewed. A parallel between the two current theoretical approaches to diffraction, the DIS picture in the Breit frame and the dipole picture in the target frame, is given, accompanied by a description of the models to which the data are compared. A recent calculation of the rescattering corrections, which hints at the universality of the diffractive parton distribution functions, is presented. The concept of generalized parton distributions is discussed together with the first measurement of the processes which might give access to them. Particular emphasis is given to the HERA data, to motivate why hard diffraction in deep inelastic scattering is viewed as an unrivalled instrument to shed light on the still obscure aspects of hadronic interactions.Comment: invited talk at the XX International Symposium on Lepton and Photon Interactions at High Energies, Rome, Italy, July 200

Agglomeration, related variety and vertical integration

Several recent studies investigate the relation between geographic concentration of production and vertical integration, based on the hypothesis that spatial agglomeration of firms in the same industry facilitates input procurement thereby reducing the degree of vertical integration. The present paper contributes to this debate by also considering the effects of industry variety at the local level. Specifically, we consider two forms of variety: unrelated variety and vertically related variety. The latter index is constructed using information drawn from input-output tables and captures the opportunities for outsourcing within the local system. We consider inter-industry vertical integration by taking account of the ownership of activities with input-output linkages. Using a dataset of 24,663 Italian business groups in 2001, we estimate Tobit models to investigate the influence of vertically related variety and other agglomeration forces on the degree of vertical integration of groups. Our evidence confirms that vertical integration is influenced by industry specialization at the local level. We also find that the higher the vertically related variety, the lower the need for firms to integrate activities since they have more opportunities to acquire intermediate goods and services within the local system.vertical integration, agglomeration, related-variety, business group

A Frequency-selective Filter for Short-Length Time Series

An effective and easy-to-implement frequency filter is designed by convolving a Hamming window with the ideal rectangular filter response function. Three other filters, Hodrick-Prescott, Baxter-King, and Christiano-Fitzgerald, are critically reviewed. The behavior of the Hamming-windowed filter is compared to the others through their frequency responses and their application to both an artificial, known-structure series and to the Euro zone quarterly GDP series. The Hamming-windowed filter has almost no leakage and is thus much better than the others in eliminating high-frequency components and has a significantly flatter bandpass response. Its low-frequency behavior demonstrates better removal of undesired long-term components. These improvements are particularly evident when working with short-length time series, such as are common in macroeconomics. The proposed filter is stationary, symmetric, uses all the information contained in the raw data, and stationarizes series integrated up to order two. It thus proves to be a good candidate for extracting frequency-defined business-cycle componentsspectral analysis, bandpass filtering

Do agglomeration and technology affect vertical integration? Evidence from Italian business groups

The aim of this paper is to analyse the role of technology and spatial agglomeration in decisions about vertical integration. It starts from the hypotheses that the business group, defined as a set of firms under common ownership and control, is the appropriate unit to delimit the firm’s boundary. We use information drawn from input-output tables to detect the presence of positive inter-industry exchanges and whether or not activities in a group are vertically related. Accounting for endogeneity problems, we estimate Probit and Linear Probability models to empirically investigate the role of technology and spatial agglomeration on vertical integration decisions. Consistent with property rights theory, our results show that the technology intensity of acquirers matters for backward integration choices and moreover, that agglomeration plays a role in vertical integration only when it operates jointly with technology.Business groups, spatial agglomeration, technology, vertical integration

The Role of Agglomeration and Technology in Shaping Firm Strategy and Organization

Over the last few years a growing number of contributions have shown that the presence of business groups, i.e. sets of firms legally distinct but belonging to the same owner(s), is significant. From a theoretical point of view, this presence poses the question of whether the group or the single legal unit should be considered as the elementary unit in economic analysis: i.e., what is generally meant in microeconomic theory by ‘firm’. In this paper we consider the group as the appropriate unit to delimit the firm’s boundary, i.e. as the ‘observed’ organizational form adopted by firms when they grow in size. Starting from this hypothesis, the main aim of this paper is to analyse the role of structural variables, such as spatial agglomeration and technology, in determining some features of business groups’ strategy and organization. Specifically, the analysis concerns the presence and organizational specificity of business groups based on their membership of industrial districts (as a proxy for spatial agglomeration) and to the role of spatial agglomeration and technology in vertical integration strategies. To conduct the analysis, we take advantage of a new and large data-set at firm and business group level, recently developed by ISTAT (the Italian National Statistical Institute). The data-set, referring to 2001, covers all manufacturing firms organized as joint-stock companies.Business Groups, Agglomeration, Technology, Organisation and Strategy

Nonequilibrium stationary state for a damped rotator

Perturbative construction of the nonequilibrium steady state of a rotator under a stochastic forcing while subject to torque and frictionComment: 18 page

Entrepreneurship education in Italian universities: trend, situation and opportunities

The aim of this paper is to provide an analysis of the present situation and recent evolution in entrepreneurship courses and curricula in Italian universities. The analysis is based on a census of entrepreneurship courses and curricula run by Italian universities in 2004 and 2010. Entrepreneurship education in Italian universities is in its early development. Up to 2004 only a few universities had courses dedicated to entrepreneurship and the majority of them dealt with the development of the business plan. This situation has only slightly improved in the following years. Courses and curricula are mostly within business schools while very few exist in engineering and science schools. This situation contrasts with the need for entrepreneurship education in the Italian economy. Given the importance of traditional sectors in Italian industry we need to stimulate start-up in high-tech sectors: the development of entrepreneurship courses in engineering and in other science curricula could play an important role in this sense. At the same time we need to favor the growth process of small firms; this requires people who are able to play an entrepreneurial role in established firms.entrepreneurship education, university courses, intrapreneurship, entrepreneurial competences.