Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy

During the Space Telescope and Optical Reverberation Mapping Project observations of NGC 5548, the continuum and emission-line variability became decorrelated during the second half of the six-month-long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide the Swift data into on- and off-anomaly spectra to characterize the soft excess via spectral fitting. The cause of the spectral differences is likely due to a change in the intrinsic spectrum rather than to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with the Swift data. Our preferred model of the soft excess is emission from an optically thick, warm Comptonizing corona, the effective optical depth of which increases during the anomaly. This model simultaneously explains all three observations: the UV emission-line flux decrease, the soft-excess increase, and the emission-line anomaly

Work context and the definition of self: How organizational care influences organization-based self-esteem

Academy of Management Journal455894-90

Effects of interpersonal trust on employee avoidance and approach self-regulation

Academy of Management 2009 Annual Meeting: Green Management Matters, AOM 2009

Leadership Redundancy in a Multiteam System

Inspection, maintenance, and repair (IMR) operations of the subsea infrastructure off Norway’s coast are performed from specialized vessels by multiteam systems. A case study shows how leadership is organized and practiced to coordinate interdependencies, and to cope with the risks inherent in this type of complex and tightly coupled operation. Leadership redundancy is proposed as a mechanism that can contribute to the smooth and safe functioning of a multiteam system operating in a volatile environment

Privacy Preserving Reputation Management in Social Networks

International audienceReputation management is a powerful security tool that helps establish the trustworthiness of users in online applications. One of the most successful use of reputation systems is in e-commerce web sites such as eBay.com and Amazon.com which use reputation systems to root out fraudulent sellers. Reputation systems can also play an important role in social networks to enforce various security requirements. For example, a reputation system can help filter fake user profiles. However, a major challenge in developing reputation systems for social networks is that users often hesitate to publicly rate fellow users or friends due to the fear of retaliation. This trend prevents a reputation system from accurately computing reputation scores. Privacy preserving reputation systems hide the individual ratings of users about others and only reveal the aggregated community reputation score thus allowing users to rate without the fear of retaliation. In this chapter, we describe privacy preserving reputation management in social networks and the associated challenges. In particular we will look at privacy preserving reputation management in decentralized social networks, where there is no central authority or trusted third parties, thus making the task of preserving privacy particularly challenging