A general method for solving surface structures in three dimensions using surface x-ray-diffraction data coupled with direct methods is outlined. The method exploits the existence of a support constraint normal to the surface, and couples the concepts of projections, operators, and sets used in the image reconstruction literature with statistical operators used in direct methods. The approach p...

A large fraction of US public stock is held by institutional investors that frequently hold shares in multiple firms in the same industry (“common ownership”). Concerns have been raised that common ownership might harm competition if it confers influence over important strategic decisions. Using data from the airline industry, we estimate the effects of common ownership on airline prices using ...

A coordinate-free version of the approach to mechanical systems with non-ideal restrictions developed by Udwadia (2002) and Udwadia and Kalaba (2002) in a series of articles is introduced. Some of its properties are then reinterpreted in a general geometric setting in terms of orthogonal projections. A geometric view of other aspects of constrained systems, inspired by their insight, is also pr...

Animals use acoustic signals across a variety of social behaviors, particularly courtship. In Drosophila, song is detected by antennal mechanosensory neurons and further processed by second-order aPN1/aLN(al) neurons. However, little is known about the central pathways mediating courtship hearing. In this study, we identified a male-specific pathway for courtship hearing via third-order ventrol...

Suppose X is a Hilbert space and C

This paper introduces a new way to measure divergence of output across countries. It measures how productivity, technology or output per worker in each country follow the global frontier. We find that during the years 1970-2008 most countries followed the global frontier only partially, so they diverged from it. We use the tools of ‘development accounting’ to measure by how much countries follo...

Over 6000 adult managers attending an assessment centre completed the MBTI and also specified in detail how long it had been before they were promoted to a managerial role, and also, where appropriate, to a senior managerial role. Correlational analyses showed shorter times to promotion were associated with being Extraverted and a Sensing Type. Regressions showed that Feeling types took longer ...

Several anterograde and retrograde tracing studies have provided detailed information on the afferent and efferent projections as well as the intrinsic connectivities of the endopiriform nucleus (EN). Here, we summarise EN connectional data and the principles of their organisation and discuss the role they may play in the development and spread of epileptic seizures.

We describe a new Zome-like system that exhibits octahedral rather than icosahedral symmetry, and illustrate its application to 3-dimensional projections of 4-dimensional regular polychora. Furthermore, we explain the existence of that system, as well as an infinite family of related systems, in terms of Hamilton’s quaternions and the binary icosahedral group. Finally, we describe a remarkably ...

Conditions are established on a polynomial f in two variables under which the equality f(P1, P2) = 0 for two orthogonal projections P1, P2 is possible only if P1 and P2 commute.