Integrability and non-perturbative effects in the AdS/CFT correspondence

We present a non-perturbative resummation of the asymptotic strong-coupling expansion for the dressing phase factor of the AdS_5xS^5 string S-matrix. The non-perturbative resummation provides a general form for the coefficients in the weak-coupling expansion, in agreement with crossing symmetry and transcendentality. The ambiguities of the non-perturbative prescription are discussed together with the similarities with the non-perturbative definition of the c=1 matrix model.Comment: 8 pages. Late

The magnon kinematics of the AdS/CFT correspondence

The planar dilatation operator of N=4 supersymmetric Yang-Mills is the hamiltonian of an integrable spin chain whose length is allowed to fluctuate. We will identify the dynamics of length fluctuations of planar N=4 Yang-Mills with the existence of an abelian Hopf algebra Z symmetry with non-trivial co-multiplication and antipode. The intertwiner conditions for this Hopf algebra will restrict the allowed magnon irreps to those leading to the magnon dispersion relation. We will discuss magnon kinematics and crossing symmetry on the spectrum of Z. We also consider general features of the underlying Hopf algebra with Z as central Hopf subalgebra, and discuss the giant magnon semiclassical regime.Comment: 21 pages, Latex. v2: Minor changes and additional reference

Why have workers stopped joining unions? The rise in never-membership in Britain

This paper tracks the rise in the percentage of employees who have never become union members (‘never-member’) since the early 1980s and shows that it is the reduced likelihood of ever becoming a member, rather than the haemorrhaging of existing members, that is behind the decline in overall union membership in Britain. We estimate the determinants of ‘never-membership’ and consider how much of the rise can be explained by structural change in the labour market and how much by change in preferences among employees

M-Theory, Torons and Confinement

We study the decompactification limit of M-theory superpotentials for N=1 four dimensional supersymmetric gauge theories. These superpotentials can be interpreted as generated by toron configurations. The connection with the confinement picture in the maximal abelian gauge is discussed.Comment: Latex file. 9 pages. Lecture given by C. G. at the XXXIII Karpacz School: "Duality, Strings and Fields". February 1997. Improved version, with a clarifying exposition on the dynamical role of torons in M-theory include

M and F-Theory Instantons, N=1 Supersymmetry and Fractional Topological Charges

We analize instanton generated superpotentials for three dimensional N=2 supersymmetric gauge theories obtained by compactifying on S^1 N=1 four dimensional theories. In the N_f=1 case, we find that the vacua in the decompactification limit is given by the singular points of the Coulomb branch of the N=2 four dimensional theory (we also consider the massive case). The decompactification limit of the superpotential for pure gauge theories without chiral matter is interpreted in terms of `t Hooft's fractional instanton amplitudes.Comment: Latex file. 11 pages. Typos corrected. Section on QCD has been rewritten, clarifying some points, and a reference has been added. Final version to appear at Int. Jour. Mod. Phys.

What Do Unions Do to Executive Compensation?

We estimate the relation between union presence and executive compensation using a unique panel of executives in publicly listed US firms during the period 1992-2001. We find evidence that union presence is associated with lower levels of total executive compensation. We find this union effect to be primarily the result of substantially lower stock option awards, and to a lesser extent due to lower cash pay. Moreover, the negative relation between unionization and executive remuneration becomes larger at the higher end of the conditional distribution of executive remuneration. We also find that the elasticity of cash pay to financial performance is similar across unionized and non-unionized firms, and that union presence is associated with a more compressed intra-firm and inter-firm executive compensation structure.Unions, executive compensation, Implicit regulation

Why Have Workers Stopped Joining Unions?

This paper tracks the rise in the percentage of employees who have never become union members (¿nevermembers¿) since the early 1980s and shows that it is the reduced likelihood of ever becoming a member rather than the haemorrhaging of existing members which is behind the decline in overall union membership in Britain. We estimate the determinants of ¿never-membership¿ and consider how much of the rise can be explained by structural change in the labour market and how much by change in preferences among employees. We find a similar trend in the unionised sector, indicating that the rise in never-membership for the economy as a whole is not linked solely to a decline in the number of recognised workplaces.Union membership

Why have workers stopped joining unions? Accounting for the rise in never-membership in Britain.

This paper tracks the rise in the percentage of employees who have never become union members (‘never-members’) since the early 1980s and shows that it is the reduced likelihood of ever becoming a member rather than the haemorrhaging of existing members which is behind the decline in overall union membership in Britain. We estimate the determinants of ‘never-membership’ and consider how much of the rise can be explained by structural change in the labour market and how much by change in preferences among employees. We find a similar trend in the unionised sector, indicating that the rise in never membership for the economy as a whole is not linked solely to a decline in the number of recognised workplaces.