Boston College

About: Boston College is a education organization based out in Boston, Massachusetts, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 9749 authors who have published 25406 publications receiving 1105145 citations. The organization is also known as: BC.

A metamaterial solid-state terahertz phase modulator

Abstract: Using a single layer of electrically controlled metamaterial, researchers have achieved active control of the phase of terahertz waves and demonstrated high-speed broadband modulation.

Enhanced routines for instrumental variables/generalized method of moments estimation and testing

Abstract: We extend our 2003 paper on instrumental variables and generalized method of moments estimation, and we test and describe enhanced routines that address heteroskedasticity- and autocorrelation-cons...

THE DARK SIDE OF ORGANIZATIONS: Mistake, Misconduct, and Disaster

Abstract: ▪ Abstract In keeping with traditional sociological concerns about order and disorder, this essay addresses the dark side of organizations. To build a theoretical basis for the dark side as an integrated field of study, I review four literatures in order to make core ideas of each available to specialists in the others. Using a Simmelian-based case comparison method of analogical theorizing, I first consider sociological constructs that identify both the generic social form and the generic origin of routine nonconformity: how things go wrong in socially organized settings. Then I examine three types of routine nonconformity with adverse outcomes that harm the public: mistake, misconduct, and disaster produced in and by organizations. Searching for analogies and differences, I find that in common, routine nonconformity, mistake, misconduct, and disaster are systematically produced by the interconnection between environment, organizations, cognition, and choice. These patterns amplify what is known about so...

Random matrix approach to cross correlations in financial data.

Abstract: We analyze cross correlations between price fluctuations of different stocks using methods of random matrix theory (RMT). Using two large databases, we calculate cross-correlation matrices C of returns constructed from (i) 30-min returns of 1000 US stocks for the 2-yr period 1994-1995, (ii) 30-min returns of 881 US stocks for the 2-yr period 1996-1997, and (iii) 1-day returns of 422 US stocks for the 35-yr period 1962-1996. We test the statistics of the eigenvalues lambda(i) of C against a "null hypothesis" - a random correlation matrix constructed from mutually uncorrelated time series. We find that a majority of the eigenvalues of C fall within the RMT bounds [lambda(-),lambda(+)] for the eigenvalues of random correlation matrices. We test the eigenvalues of C within the RMT bound for universal properties of random matrices and find good agreement with the results for the Gaussian orthogonal ensemble of random matrices-implying a large degree of randomness in the measured cross-correlation coefficients. Further, we find that the distribution of eigenvector components for the eigenvectors corresponding to the eigenvalues outside the RMT bound display systematic deviations from the RMT prediction. In addition, we find that these "deviating eigenvectors" are stable in time. We analyze the components of the deviating eigenvectors and find that the largest eigenvalue corresponds to an influence common to all stocks. Our analysis of the remaining deviating eigenvectors shows distinct groups, whose identities correspond to conventionally identified business sectors. Finally, we discuss applications to the construction of portfolios of stocks that have a stable ratio of risk to return. (Less)