Broadcast Channels with Cooperating Decoders

We consider the problem of communicating over the general discrete memoryless broadcast channel (BC) with partially cooperating receivers. In our setup, receivers are able to exchange messages over noiseless conference links of finite capacities, prior to decoding the messages sent from the transmitter. In this paper we formulate the general problem of broadcast with cooperation. We first find the capacity region for the case where the BC is physically degraded. Then, we give achievability results for the general broadcast channel, for both the two independent messages case and the single common message case.Comment: Final version, to appear in the IEEE Transactions on Information Theory -- contains (very) minor changes based on the last round of review

Analysis of somatic mutations across the kinome reveals loss-of-function mutations in multiple cancer types

AbstractIn this study we use somatic cancer mutations to identify important functional residues within sets of related genes. We focus on protein kinases, a superfamily of phosphotransferases that share homologous sequences and structural motifs and have many connections to cancer. We develop several statistical tests for identifying Significantly Mutated Positions (SMPs), which are positions in an alignment with mutations that show signs of selection. We apply our methods to 21,917 mutations that map to the alignment of human kinases and identify 23 SMPs. SMPs occur throughout the alignment, with many in the important A-loop region, and others spread between the N and C lobes of the kinase domain. Since mutations are pooled across the superfamily, these positions may be important to many protein kinases. We select eleven mutations from these positions for functional validation. All eleven mutations cause a reduction or loss of function in the affected kinase. The tested mutations are from four genes, including two tumor suppressors (TGFBR1 and CHEK2) and two oncogenes (KDR and ERBB2). They also represent multiple cancer types, and include both recurrent and non-recurrent events. Many of these mutations warrant further investigation as potential cancer drivers.</jats:p

Productivity and the Euro-Dollar Exchange Rate Puzzle

This paper documents the evidence for a productivity based model of the dollar/euro real exchange rate over the 1985-2001 period. We estimate cointegrating relationships between the real exchange rate, productivity, and the real price of oil using the Johansen (1988) and Stock-Watson (1993) procedures. We find that each percentage point in the US-Euro area productivity differential results in a five percentage point real appreciation of the dollar. This finding is robust to the estimation methodology, the variables included in the regression, and the sample period. We conjecture that productivity-based models cannot explain the observed patterns with the standard set of assumptions, and describe a case in which the model can be reconciled with the observed data.

Structure and Trends of Rural Employment: Canada in the Context of OECD Countries

In 1991, 33 percent of Canada's population lived in predominantly rural regions. Employment growth in rural regions averaged 1.3 percent per year over the 1980s, ranking fourth among OECD countries. In 1991, only 11 percent of the rural workforce in Canada were working in agriculture, forestry or fishing. Within rural regions, employment growth was highest in rural areas adjacent to metropolitan centres. Business services was the fastest growing sector in all types of regions, but rural regions received only a minor boost due to the relatively low share of their workforce in business services. On average, rural areas showed less growth - however, within rural areas, there were regions that showed more growth than urban regions. Rurality does not necessarily imply slow employment growth.Community/Rural/Urban Development, Labor and Human Capital,