Free products of sofic groups with amalgamation over monotileably amenable groups

We show that free products of sofic groups with amalgamation over monotileably amenable subgroups are sofic. Consequently, so are HNN extensions of sofic groups relative to homomorphisms of monotileably amenable subgroups. We also show that families of independent uniformly distributed permutation matrices and certain families of non-random permutation matrices (essentially, those coming from quasi--actions of a sofic group) are asymptotically *-free as the matrix size grows without bound.Comment: 16 pages. Version 2 has a shorter proof of Lemma 2.2, thanks to Ion Nechita. Version 3 corrects a mistake. The previous Lemma 3.1 was incorrect. Version 3 has a new proof of the main result, but it is (apparently) weaker than in Version 2. Note that the paper's title also changed accordingly. Version 4 corrects a minor mistake around equation (4

ILR Impact Brief - Pathways to Success: Human Resource Practices Do Matter

[Extract] Most researchers agree that human resource (HR) practices affect attitudes and discretionary behavior on the job and that employee actions and motivations influence company performance. The academic literature also suggests that investing in employees, through high-commitment HR practices such as internal labor markets, selecting new employees who “fit” the company rather than a particular job, compensating employees on the basis of group and company results, and training and development programs that stress team building and long-term growth, are all indirectly related to organizational success. Missing from the literature is an exploration of the causal mechanisms that mediate between these HR practices and favorable outcomes for companies operating in dynamic environments; this research begins filling the void

Human Resource Practices, Knowledge-Creation Capability And Performance In High Technology Firms

This study examines the relationship among key HR practices (i.e., effective acquisition, employee-development, commitment-building, and networking practices), three dimensions of knowledge-creation capability (human capital, employee motivation, and information combination and exchange), and firm performance. Results from a sample of 78 high technology firms showed that the three dimensions of knowledge creation interact to positively affect sales growth. Further, the HR practices were found to affect sales growth through their affect on the dimensions of knowledge-creation capability

On a reduction procedure for Horn inequalities in finite von Neumann algebras

We consider the analogues of the Horn inequalities in finite von Neumann algebras, which concern the possible spectral distributions of sums $a+b$ of self--adjoint elements $a$ and $b$ in a finite von Neumann algebra. It is an open question whether all of these Horn inequalities must hold in all finite von Neumann algebras, and this is related to Connes' embedding problem. For each choice of integers $1\le r\le n$, there is a set $T^n_r$ of Horn triples, and the Horn inequalities are in one-to-one correspondence with $\cup_{1\le r\le n}T^n_r$. We consider a property P$_n$, analogous to one introduced by Therianos and Thompson in the case of matrices, amounting to the existence of projections having certain properties relative to arbitrary flags, which guarantees that a given Horn inequality holds in all finite von Neumann algebras. It is an open question whether all Horn triples in $T^n_r$ have property P$_n$. Certain triples in $T^n_r$ can be reduced to triples in $T^{n-1}_r$ by an operation we call {\em TT--reduction}. We show that property P$_n$ holds for the original triple if property P$_{n-1}$ holds for the reduced one. We then characterize the TT--irreducible Horn triples in $T^n_3$, for arbitrary $n$, and for those LR--minimal ones (namely, those having Littlewood--Richardson coefficient equal to 1), we perform a construction of projections with respect to flags in arbitrary von Neumann algebras in order to prove property P$_n$ for them. This shows that all LR--minimal triples in $\cup_{n\ge3}T^n_3$ have property P$_n$, and so that the corresponding Horn inequalities hold in all finite von Neumann algebras.Comment: 39 page

The alphaalphas2alpha alpha_s^2 corrections to the first moment of the polarized virtual photon structure function g1gamma(x,Q2,P2)g_1^gamma(x,Q^2,P^2)

We present the next-to-next-to-leading order ($alpha alpha_s^2$) corrections to the first moment of the polarized virtual photon structure function $g_1^gamma(x,Q^2,P^2)$ in the kinematical region $Lambda^2 ll P^2 ll Q^2$, where $-Q^2(-P^2)$ is the mass squared of the probe (target) photon and $Lambda$ is the QCD scale parameter. In order to evaluate the three-loop-level photon matrix element of the flavor singlet axial current, we resort to the Adler-Bardeen theorem for the axial anomaly and we calculate in effect the two-loop diagrams for the photon matrix element of the gluon operator. The $alpha alpha_s^2$ corrections are found to be about 3% of the sum of the leading order ($alpha$) andthe next-to-leading order ($alpha alpha_s$) contributions, when $Q^2=30 sim 100 {rm GeV}^2$and $P^2=3{rm GeV}^2$, and the number of active quark flavors $n_f$ is three to five.Comment: 21 page

Electromagnetic Modeling of Plasma Etch Chamber for Semiconductor Microchip Fabrication

Abstract-In the plasma etch chamber used to fabricate semiconductor microchips, maintaining the symmetry and uniformity of the electric field in the plasma discharge region is critical. Very-high-frequency (VHF) RF sources are attractive for such applications as they improve the efficiency of plasma generation. Electromagnetic effects become important at these frequencies, and etch chamber design requires careful investigation of the electromagnetic field spatial structure in the chamber. In this paper, we apply the finite-difference time-domain (FDTD) method to examine various electromagnetic effects in the plasma etch chamber and investigate strategies for improved chamber design. These effects include the standing wave effects and asymmetric field distributions that can be caused by asymmetric RF power feed configurations. The FDTD method is formulated in both cylindrical and Cartesian coordinate systems to facilitate modeling of rotationally symmetric chamber and asymmetric RF feed structures. The electric field distribution generated by various RF feed configurations is studied at different VHF frequencies. Based on the FDTD simulations, we have been able to identify a variety of design approaches for ensuring electric field symmetry and uniformity