TFM-Explorer: mining cis-regulatory regions in genomes

DNA-binding transcription factors (TFs) play a central role in transcription regulation, and computational approaches that help in elucidating complex mechanisms governing this basic biological process are of great use. In this perspective, we present the TFM-Explorer web server that is a toolbox to identify putative TF binding sites within a set of upstream regulatory sequences of genes sharing some regulatory mechanisms. TFM-Explorer finds local regions showing overrepresentation of binding sites. Accepted organisms are human, mouse, rat, chicken and drosophila. The server employs a number of features to help users to analyze their data: visualization of selected binding sites on genomic sequences, and selection of cis-regulatory modules. TFM-Explorer is available at http://bioinfo.lifl.fr/TFM

Churn, Baby, Churn: Strategic Dynamics Among Dominant and Fringe Firms in a Segmented Industry

This paper integrates and extends the literatures on industry evolution and dominant firms to develop a dynamic theory of dominant and fringe competitive interaction in a segmented industry. It argues that a dominant firm, seeing contraction of growth in its current segment(s), enters new segments in which it can exploit its technological strengths, but that are sufficiently distant to avoid cannibalization. The dominant firm acts as a low-cost Stackelberg leader, driving down prices and triggering a sales takeoff in the new segment. We identify a “churn” effect associated with dominant firm entry: fringe firms that precede the dominant firm into the segment tend to exit the segment, while new fringe firms enter, causing a net increase in the number of firms in the segment. As the segment matures and sales decline in the segment, the process repeats itself. We examine the predictions of the theory with a study of price, quantity, entry, and exit across 24 product classes in the desktop laser printer industry from 1984 to 1996. Using descriptive statistics, hazard rate models, and panel data methods, we find empirical support for the theoretical predictions

Selection of workers and firm heterogeneity

A model based on differences between workers regarding their preferences for wage and leisure drives the heterogeneity of firms result. The more industrious workers are driven to small firms due to free riding in large firms. An industry consisting of small and large firms turns out to produce more output than an industry consisting of only large firms. Some comparative statics results are derived with respect to the size of large firms, the productivity difference between firms, and monitoring capabilities

Innovation and the creative destruction of trade : a study of the intensive and extensive margins of trade for French firms

Our study of French exporters examines the causal relationship between innovation and extensive and intensive margins of trade using a propensity score matching and difference‐in‐differences approach. Results show innovation has a positive impact on total exports driven primarily through the intensive margin. To understand the absence of an extensive margin effect, we show new and terminated product–country transactions increase at similar rates in the year of innovation for the treated and control groups but net trade creation for innovators outstrips that of non‐innovators in the following two years implying firms need to innovate in order to survive in export markets

The Evolution of Grocery Wholesaling and Grocery Wholesalers in Ireland and Britain since the 1930s

Studies of industry evolution are relatively scarce outside of industries defined by narrow technological bases. Studies of wholesaling are rarer still. These are curious features given that it is probable that service industries behave differently to manufacturing ones and that wholesaling is such a key function of many economies. This paper looks at the evolution of grocery wholesaling and grocery wholesalers in Ireland and Britain since 1930. It focuses on the processes and drivers of the wholesale industry. Similarities and differences between the two countries are discussed. Particular emphasis is placed on the role of government action as a triggering mechanism for change and on the role of trade associations and industry leaders in developing and following through on market and non-market strategies. The pathways of industry evolution identified differ from those seen in manufacturing. They therefore raise a number of issues for the development of understanding and conceptualisation in industry evolution studies