The Future of Civil War History

In March 2013, hundreds of academics, preservationists, consultants, historical interpreters, museum professionals, living historians, students, K-12 teachers, and new media specialists gathered in Gettysburg, Pennsylvania to assess the state and potential future of the study of the American Civil War. The essays in this special issue build on the themes of that conference: embracing the democratic and civic potential of historical thinking; reaffirming the power of place and the importance of specific, focused stories; integrating military, political, social, cultural, and gender history; and encouraging collaboration among historians working in different settings. Our three guest editors offer their own thoughts about the state and potential future of Civil War history. [excerpt

Optimal control systems. Part II, Synthesis: The synthesis of optimum and quasi-optimum minimum time controls for second order systems

This paper discusses briefly the digital and analog synthesis of several optimum and quasi-optimum minimum-time controls for systems with real, null, and complex eigenvalues „ Controls are designed using nonlinear feedback. Examples demonstrate the simplicity of the design. An example of the control of a nonlinear system is given using a technique which is effectively a linearization of the system about each state point on a trajectory. A quasi-optimum minimum-time control is generated by substituting the nonlinear functions of the states for their respective linearized characteristics.Office of Naval Researchhttp://archive.org/details/optimalcontrolsy00tit

Structural studies of cerebral cavernous malformations 2 (CCM2) reveal a folded helical domain at its C-terminus

AbstractCerebral cavernous malformations (CCM) are neurovascular dysplasias affecting up to 0.5% of the population. Mutations in the CCM2 gene are associated with acquisition of CCM. We identify a previously uncharacterized domain at the C-terminus of CCM2 and determine its 1.9Å resolution crystal structure. Because this domain is structurally homologous to the N-terminal domain of harmonin, we name it the CCM2 harmonin-homology domain or HHD. CCM2 HHD is observed in two conformations, and we employ analytical ultracentrifugation to test its oligomerization. Additionally, CCM2 HHD contains an unusually long 13-residue 310 helix. This study provides the first structural characterization of CCM2.Structured summary of protein interactionsCCM2 binds to CCM3 by pull down (View interaction)CCM2 and CCM2 bind by X-ray crystallography (View interaction)CCM2 and CCM2 bind by molecular sieving (View interaction

1.3 mm Wavelength VLBI of Sagittarius A*: Detection of Time-Variable Emission on Event Horizon Scales

Sagittarius A*, the ~4 x 10^6 solar mass black hole candidate at the Galactic Center, can be studied on Schwarzschild radius scales with (sub)millimeter wavelength Very Long Baseline Interferometry (VLBI). We report on 1.3 mm wavelength observations of Sgr A* using a VLBI array consisting of the JCMT on Mauna Kea, the ARO/SMT on Mt. Graham in Arizona, and two telescopes of the CARMA array at Cedar Flat in California. Both Sgr A* and the quasar calibrator 1924-292 were observed over three consecutive nights, and both sources were clearly detected on all baselines. For the first time, we are able to extract 1.3 mm VLBI interferometer phase information on Sgr A* through measurement of closure phase on the triangle of baselines. On the third night of observing, the correlated flux density of Sgr A* on all VLBI baselines increased relative to the first two nights, providing strong evidence for time-variable change on scales of a few Schwarzschild radii. These results suggest that future VLBI observations with greater sensitivity and additional baselines will play a valuable role in determining the structure of emission near the event horizon of Sgr A*.Comment: 8 pages, submitted to ApJ

Amyloid angiopathy of the floor of the mouth: a case report and review of the literature

Amyloidosis is a rare disease characterised by the deposition of insoluble extracellular fibrillar proteins in various tissues of the body. The pattern of manifestation is organ dependent and also on whether the disease is localised or systemic, primary or secondary

Detection of intrinsic source structure at ~3 Schwarzschild radii with Millimeter-VLBI observations of SAGITTARIUS A*

We report results from very long baseline interferometric (VLBI) observations of the supermassive black hole in the Galactic center, Sgr A*, at 1.3 mm (230 GHz). The observations were performed in 2013 March using six VLBI stations in Hawaii, California, Arizona, and Chile. Compared to earlier observations, the addition of the APEX telescope in Chile almost doubles the longest baseline length in the array, provides additional {\it uv} coverage in the N-S direction, and leads to a spatial resolution of $\sim$30 $\mu$as ($\sim$3 Schwarzschild radii) for Sgr A*. The source is detected even at the longest baselines with visibility amplitudes of $\sim$4-13% of the total flux density. We argue that such flux densities cannot result from interstellar refractive scattering alone, but indicate the presence of compact intrinsic source structure on scales of $\sim$3 Schwarzschild radii. The measured nonzero closure phases rule out point-symmetric emission. We discuss our results in the context of simple geometric models that capture the basic characteristics and brightness distributions of disk- and jet-dominated models and show that both can reproduce the observed data. Common to these models are the brightness asymmetry, the orientation, and characteristic sizes, which are comparable to the expected size of the black hole shadow. Future 1.3 mm VLBI observations with an expanded array and better sensitivity will allow a more detailed imaging of the horizon-scale structure and bear the potential for a deep insight into the physical processes at the black hole boundary.Comment: 11 pages, 5 figures, accepted to Ap