Quasi-Local Energy Flux of Spacetime Perturbation

A general expression for quasi-local energy flux for spacetime perturbation is derived from covariant Hamiltonian formulation using functional differentiability and symplectic structure invariance, which is independent of the choice of the canonical variables and the possible boundary terms one initially puts into the Lagrangian in the diffeomorphism invariant theories. The energy flux expression depends on a displacement vector field and the 2-surface under consideration. We apply and test the expression in Vaidya spacetime. At null infinity the expression leads to the Bondi type energy flux obtained by Lindquist, Schwartz and Misner. On dynamical horizons with a particular choice of the displacement vector, it gives the area balance law obtained by Ashtekar and Krishnan.Comment: 8 pages, added appendix, version to appear in Phys. Rev.

W-band waveguide-packaged InP HEMT reflection grid amplifier

This letter presents a 79-GHz broadband reflection-type grid amplifier using spatial power combining to combine the power of 64 unit cells. Each unit cell uses a two-stage cascade configuration with InP HEMTs arranged as a differential pair. A broadband orthogonal mode transducer (OMT) separates two orthogonally polarized input and output signals over a 75 to 85GHz range. In conjunction with the OMT, a mode converter with quadruple-ridged apertures was designed to enhance the field uniformity over the active grid. Measurements show 5-dB small signal gain at 79GHz and an 800-MHz 3-dB bandwidth. The amplifier generates an output power of 264mW with little evidence of saturation

Legislative History Is Dead; Long Live Legislative History

Review of Victoria Nourse, Misreading Law, Misreading Democracy (Harvard 2016

Collaboration between Legal Writing Faculty and Law Librarians: Two Surveys

Legal writing faculty and law librarians have overlapping expertise and responsibility for developing law students’ legal research skills. Within the first-year of law school, there are many ways that legal writing faculty and law librarians apportion the teaching of legal research. Some involve a great deal of collaboration—others almost none. I was curious to know what legal writing faculty really think about their law librarian colleagues and their role in legal research instruction, and vice-versa. Are law librarians and legal writing faculty natural institutional allies, competitors, or something else? To explore these questions I surveyed academic law librarians and legal writing faculty, asking them to anonymously share their opinions about teaching 1L legal research and collaborating with members of the other group. I drafted two separate surveys, using parallel sets of questions framed to address each group individually, in order to compare their perspectives. Despite the limitations of this method, the results suggest a set of inter-related observations. First, generally speaking, the roles librarians are most likely to play in 1L legal research teaching are those that require the least formal engagement with legal writing faculty. Second, librarians who play a formal role teaching legal research to 1Ls have similar preferences to their legal writing faculty counterparts when it comes to using assignments, requiring textbooks, and incorporating research skills over the course of a class. Third, librarians and legal writing faculty express a range of views what successful 1L legal research teaching should look like, and while there are some significant differences between their perspectives, respondents from both groups identified benefits from collaborating to teach legal research, both to students and themselves. This article will begin with an overview of how legal research is taught in the first year of J.D. programs, and how this approach has changed over time. It will then discuss the limited literature that characterizes the relationship between law librarians and legal writing faculty. The article will describe my surveys and their results, including comments made by the surveys’ respondents. These results lead me to conclude that improved collaboration has the potential to improve legal research teaching in the first year. Finally, I will offer some suggestions for improving collaboration and using it for legal writing faculty and law librarians’ mutual benefit