University of Pennsylvania

About: University of Pennsylvania is a education organization based out in Philadelphia, Pennsylvania, United States. It is known for research contribution in the topics: Population & Medicine. The organization has 109318 authors who have published 257688 publications receiving 14150562 citations. The organization is also known as: UPenn & Penn.

When Are Contrarian Profits Due to Stock Market Overreaction

Abstract: If returns on some stocks systematically lead or lag those of others, a portfolio strategy that sells "winners" and buys "losers" can produce positive expected returns, even if no stock's returns are negatively autocorrelated as virtually all models of overreaction imply. Using a particular contrarian strategy, the authors show that, despite negative autocorrelation in individual stock returns, weekly portfolio returns are strongly positively autocorrelated and are the result of important cross-autocorrelations. The authors find that the returns of large stocks lead those of smaller stocks, and present evidence against overreaction as the only source of contrarian profits. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.

Correlates of Protection Induced by Vaccination

Abstract: This paper attempts to summarize current knowledge about immune responses to vaccines that correlate with protection. Although the immune system is redundant, almost all current vaccines work through antibodies in serum or on mucosa that block infection or bacteremia/viremia and thus provide a correlate of protection. The functional characteristics of antibodies, as well as quantity, are important. Antibody may be highly correlated with protection or synergistic with other functions. Immune memory is a critical correlate: effector memory for short-incubation diseases and central memory for long-incubation diseases. Cellular immunity acts to kill or suppress intracellular pathogens and may also synergize with antibody. For some vaccines, we have no true correlates, but only useful surrogates, for an unknown protective response.

Sustainable Operations Management

Abstract: Operations management researchers and practitioners face new challenges in integrating issues of sustainability with their traditional areas of interest. During the past 20 years, there has been growing pressure on businesses to pay more attention to the environmental and resource consequences of the products and services they offer and the processes they deploy. One symptom of this pressure is the movement towards triple bottom line reporting (3BL) concerning the relationship of profit, people, and the planet. The resulting challenges include integrating environmental, health, and safety concerns with green-product design, lean and green operations, and closed-loop supply chains. We review these and other “sustainability” themes covered in the first 50 issues of Production and Operations Management and conclude with some thoughts on future research challenges in sustainable operations management.

Process Management and Technological Innovation: A Longitudinal Study of the Photography and Paint Industries:

Abstract: This research explores the impact of process management activities on technological innovation. Drawing on research in organizational evolution and learning, we suggest that as these practices reduce variance in organizational routines and influence the selection of innovations, they enhance incremental innovation at the expense of exploratory innovation. We tested our hypotheses in a 20-year longitudinal study of patenting activity and ISO 9000 quality program certifications in the paint and photography industries. In both industries, the extent of process management activities in a firm was associated with an increase in both exploitative innovations that built on existing firm knowledge and an increase in exploitation's share of total innovations. Our results suggest that exploitation crowds out exploration. We extend existing empirical research by capturing how process management activities influence the extent to which innovations build on existing firm knowledge. We suggest that these widely adopted...