Noncentral limit theorem for the generalized Rosenblatt process

We use techniques of Malliavin calculus to study the convergence in law of a family of generalized Rosenblatt processes $Z_\gamma$ with kernels defined by parameters $\gamma$ taking values in a tetrahedral region $\Delta$ of \RR^q. We prove that, as $\gamma$ converges to a face of $\Delta$, the process $Z_\gamma$ converges to a compound Gaussian distribution with random variance given by the square of a Rosenblatt process of one lower rank. The convergence in law is shown to be stable. This work generalizes a previous result of Bai and Taqqu, who proved the result in the case $q=2$ and without stability

Modeling grain boundaries in solids using a combined nonlinear and geometrical method

The complex arrangements of atoms near grain boundaries are difficult to understand theoretically. We propose a phenomenological (Ginzburg-Landau-like) description of crystalline phases based on symmetries and fairly general stability arguments. This method allows a very detailed description of defects at the lattice scale with virtually no tunning parameters, unlike usual phase-field methods. The model equations are directly inspired from those used in a very different physical context, namely, the formation of periodic patterns in systems out-of-equilibrium ({\it e.g.} Rayleigh-B\'enard convection, Turing patterns). We apply the formalism to the study of symmetric tilt boundaries. Our results are in quantitative agreement with those predicted by a recent crystallographic theory of grain boundaries based on a geometrical quasicrystal-like construction. These results suggest that frustration and competition effects near defects in crystalline arrangements have some universal features, of interest in solids or other periodic phases.Comment: 10 pages, 3 figure

Reluctant leaders : an analysis of middle managers' perceptions of leadership in further education in England

The research that forms the basis for this article draws attention to a group of middle managers who are reluctant to become leaders because they seek more space and autonomy to stay in touch with their subject, their students, and their own pedagogic values and identities, family commitments and the balance between work and life. This reluctance is reinforced by their scepticism that leadership in Further Education (FE) is becoming less hierarchical and more participative. In a sector that has had more than its fair share of reformist intervention, there is some scepticism of the latest fad of distributed and transformative leadership as a new panacea to cure all the accumulated 'ills' of Further Education in England. Although focused primarily on this one sector in an English context, the article draws some inferences where there are parallels with wider sectors of public sector reform and where the uneasy (and incomplete) transitions from 'old' to 'new' public management have been underpinned by invasive audit, inspection and performance cultures

PT-symmetric waveguides

We introduce a planar waveguide of constant width with non-Hermitian PT-symmetric Robin boundary conditions. We study the spectrum of this system in the regime when the boundary coupling function is a compactly supported perturbation of a homogeneous coupling. We prove that the essential spectrum is positive and independent of such perturbation, and that the residual spectrum is empty. Assuming that the perturbation is small in the supremum norm, we show that it gives rise to real weakly-coupled eigenvalues converging to the threshold of the essential spectrum. We derive sufficient conditions for these eigenvalues to exist or to be absent. Moreover, we construct the leading terms of the asymptotic expansions of these eigenvalues and the associated eigenfunctions.Comment: LaTeX, 25 pages; more detailed description of various types of spectra; version accepted for publication in Integral Equations Operator Theor

Challenging dualism : public professionalism in ‘troubled’ times

In recent decades neo-liberal reform has significantly impacted on public sector professionals. Sociological interest in such impact has tended to focus on professionals as subjects of such reform: as either de-professionalized ‘victims’ who feel oppressed by the structures of control or strategic operators seeking to contest the spaces and contradictions of market, managerial and audit cultures. Such a dualism is reflective of wider separations of agency and structure that have plagued sociology down the years. Our approach challenges modernizing agendas which seek to re-professionalize or empower professionals without examining the changing conditions of their work or the neo-liberal conditions which frame their practice. It also questions the policy outcomes of reconciling the dualism between agency and structure through a ‘third way’ politics that purports to remove the tensions and conflicts between professions and various stakeholders, the private and the public, and markets and civic society

Entrepreneurship in Equilibrium

This paper compares the financing of new ventures in start-ups (entrepreneurship) and in established firms (intrapreneurship). Intrapreneurship allows established firms to use information on failed intrapreneurs to redeploy them into other jobs. By contrast, failed entrepreneurs must seek other jobs in an imperfectly informed external labor market. While this external labor market leads to ex post inefficient allocations, it provides entrepreneurs with high-powered incentives ex ante. We show that two types of equilibria can arise (and sometimes coexist). In a low entrepreneurship equilibrium, the market for failed entrepreneurs is thin, making internal labor markets and intrapreneurship particularly valuable. In a high entrepreneurship equilibrium, the active labor market reduces the value of internal labor markets and encourages entrepreneurship. We also show that there can be too little or too much entrepreneurial activity. There can be too little because entrepreneurs do not take into account their positive effect on the quality of the labor market. There can be too much because a high quality labor market is bad for entrepreneurial incentives.

Who deserves aid? Equality of opportunity, international aid and poverty reduction

We build and implement a normative procedure to allocate international aid based on equality of opportunity concerning the risk of poverty. This is an alternative to Collier and Dollar’s proposal (2001) which stresses the impact of aid on worldwide poverty reduction. The big problem with their approach, as regards distributive justice, is that it leaves very great inequality in poverty risk between inhabitants of countries with widely varying structural disadvantages. We draw on post-welfarist theories of social justice, especially those of John Roemer. However our proposal is very different to that of Llavador and Roemer (2001), which has serious methodological errors and reaches contradictory conclusions. Our proposed allocations, like those of Collier and Dollar, differ from current aid allocation by giving more to the poorest countries. Apart from this agreement, our equality of opportunity principle takes account of structural disadvantages to growth rather than quality of past policies. Our kind of allocation shares out poverty risks much more fairly among the world’s population, while reducing global poverty almost as effectively as Collier and Dollar\'s.International aid, Equality of Opportunity, Poverty Reduction

Earnouts: A Study of Financial Contracting in Acquisition Agreements

We empirically examine earnout contracts, which provide for contingent payments in acquisition agreements. Our analysis reveals considerable heterogeneity in the terms of earnout contracts, i.e. the potential size of the earnout, the performance measure on which the contingent payment is based, the period over which performance is measured, the frequency with which performance is measured, and the form of payment for the earnout. Consistent with the costly contracting hypothesis, we find that the terms of earnout contracts are associated with measures of target valuation uncertainty, target growth opportunities, and the degree of post-acquisition integration between target and acquirer. We conclude that earnouts are structured to minimize the costs of adverse selection and moral hazard in acquisition negotiations.