Cooperative diversity has been recently proposed as a way to form virtual antenna arrays that provide dramatic gains in slow fading wireless environments. However most of the proposed solutions require simultaneous relay transmissions at the same frequency bands, using distributed space-time coding algorithms. Careful design of distributed space-time coding for the relay channel, is usually bas...

Inhabiting the virtual city: The design of social environments for electronic communities by Judith Stefania Donath Submitted to the Program in Media Arts and Sciences, School ofArchitecture and Planning, on October 31, 1996 in partial fulfillment of the requirements for the degree of Doctor of Philosophy. The goal of this work is to develop an approach to the design of on-line social environme...

by Michael Lippman It is always unsettling to enter the theater for a performance and f ind the actors already on stage; one can almost be int imidated, as i f the audience has interrupted a ritual which was going on before it entered and now must pay humble t r ibute. The black-tight white-face figures seemed unaware o f an expectant audience as they went through their "Free Exerc i s e . ' 1 ...

The s-wave meson-baryon interaction in the S = −1, S = 0 and S = −2 sectors is studied by means of coupled channels, using the lowestorder chiral Lagrangian and the N/D method or equivalently the BetheSalpeter equation to implement unitarity. This chiral approach leads to the dynamical generation of the Λ(1405), Λ(1670) and Σ(1620) states for S = −1, the N∗(1535) for S = 0 and the Ξ(1620) for S...

Accepting a sequence of independent positive mean bets that are individually unacceptable is what Samuelson called a fallacy of large numbers. Recently, utility functions were characterized where this occurs rationally, and examples were given of utility functions where any finite number of good bets should never be accepted.1 Here the author shows how things change if you are allowed the optio...

The commentary by Lippman et al. (1) provides a useful review of the topic by organizing a massive amount of information in an organized way. However, because this review will be widely read and referenced, there are two general points made by the authors that could be challenged. The authors define two of the four criteria for identifying a “definitive” chemoprevention trial as “primary end po...

Two recent studies, the Women’s Health Initiative (WHI) and the Million Women Study (MWS), have above all raised concerns over the relationship between progestogens and increased risk of breast cancer in the climacteric and postmenopause (Million Women Study collaborators, 2003; Writing Group, 2002). The Women’s Health Initiative study was terminated early after five years, due to an increased ...

Almost 30 years have elapsed since glucocorticoids were first used to treat human leukemias and lymphomas (6, 7, 9). However, the mechanism of the lympholytic effect remains to be determined. While glucocorticoids cause numerous bio chemical alterations in CS3 lymphocytes, no clear relationship has been established between these changes and the lethal action of the corticosteroids (36). Regardl...

From the resource-based view of the firm to the knowledge-based view of the firm it is clear that a particular intangible resource has become the cornerstone of sustainable competitive advantage (Barney, 1986; Conner, 1991; Foss, 1996; Lippman and Rumelt, 1982; Penrose, 1959). This resource is organizational knowledge. According to Peteraf’s framework (1993) “four conditions must be met for a f...

"Mosquitoes do not surrender to elephants," says Walter Lippman. In this book, P. F. Mattingly discusses some of the secrets that enable mosquitoes to be so courageous. The book is a comprehensive discussion of the natural history of mosquito-borne diseases and the mosquitoes which carry them. It primarily deals with current ecological concepts and succeeds in conveying a wealth of information ...