Model for Anisotropic Directed Percolation

We propose a simulation model to study the properties of directed percolation in two-dimensional (2D) anisotropic random media. The degree of anisotropy in the model is given by the ratio $\mu$ between the axes of a semi-ellipse enclosing the bonds that promote percolation in one direction. At percolation, this simple model shows that the average number of bonds per site in 2D is an invariant equal to 2.8 independently of $\mu$. This result suggests that Sinai's theorem proposed originally for isotropic percolation is also valid for anisotropic directed percolation problems. The new invariant also yields a constant fractal dimension $D_{f} \sim 1.71$ for all $\mu$, which is the same value found in isotropic directed percolation (i.e., $\mu = 1$).Comment: RevTeX, 9 pages, 3 figures. To appear in Phys.Rev.

The impact of business-cycle fluctuations on private-label share.

This study investigates the cyclical dependence of private-label success in four countries. The results show that private-label share behaves countercyclically. Moreover, asymmetries are present in both the extent and speed of up- and down-ward movements in private-label share over the business cycle. Finally, part of private-labels' share gain during contractions is found to be permanent.Business; Country; Dependence; Studies; Success;

Improvement of thermally formed nickel silicide by ion irradiation

A significant improvement of the lateral uniformity of thermally formed Ni_(2)Si layers has been observed after low‐dose (10^(13)~3 × 10^(14) ion/cm^2) Xe irradiation of an As‐deposited Ni film. Measurements have also been made on samples that contained a thin impurity layer formed intentionally between the silicon substrate and the evaporated nickel film. The impurity layer was thick enough to prevent thermal silicide formation in unirradiated samples, but in irradiated samples, the silicide formation was not prevented. Similar results were obtained for As implantations. We attribute this effect to ion mixing of the interfacial layer. These results demonstrate that a low‐dose irradiation can render the process of silicide formation by thermal annealing more tolerant to interfacial impurities. The concept is of potential significance to VLSI technology

Faced with excess capacity, innovative firms retain staff, train and even hire

The cost of hiring and training is low during recessions, argue Eirik Sjåholm Knudsen and Lasse B. Lie

Innovation, human capital and exogenous shocks

Strategic entrepreneurship is about the simultaneous exploitation of existing advantages and the creation and exploitation of new opportunities. These are often referred to as the strategy-and the entrepreneurship dimension, respectively. We examine how the relative emphasis on the two dimensions of strategic entrepreneurship affects how firms behave with respect to human capital in the context of one particular exogenous shock, namely recessions. We hypothesize and find that the higher the focus on the entrepreneurial dimension, the more firms invest in training, the more likely they are to hire, and the more likely they are to lay off employees. Finally, we also find that these firms are more likely to combine the accumulation of human capital through training with both hiring and firing. In sum, these findings show how challenges and opportunities created by environmental change differ depending on the relative emphasis on the two dimensions. They also show how firms focusing on the entrepreneurial dimension more actively pursue the opportunities created by increased labor market imperfections in recessions. These results contribute to the literature by highlighting how recessions affect firms’ flow of human capital investments, and subsequently stocks, depending on their weighting of the two dimensions of strategic entrepreneurship

What's the Matter with Relatedness?

A core proposition of the resource-based view of the firm is that related diversification is more efficient than unrelated diversification. Nevertheless, the empirical evidence is usually described as mixed or unstable. We empirically examine three possible explanations for the nature of these findings. One is that they reflect measurement problems. Another is that they reflect a failure to take the resource-based view far enough in terms of recognizing firm heterogeneity. The third is that the resource-based view is misspecified: relatedness is not a significant determinant of efficiency. We use a detailed line-of-business sample to examine these three explanations. Our findings clearly indicate that the main problem is measurement, and we describe an approach to overcoming these problems