Continuum Deformation of a Multiple Quadcopter Payload Delivery Team without Inter-Agent Communication

This paper proposes continuum deformation as a strategy for controlling the collective motion of a multiple quadcopter system (MQS) carrying a common payload. Continuum deformation allows expansion and contraction of inter-agent distances in a 2D motion plane to follow desired motions of three team leaders. The remaining quadcopter followers establish the desired continuum deformation only by knowing leaders positions at desired sample time waypoints without the need for inter-agent communication over the intermediate intervals. Each quadcopter applies a linear-quadratic-Gaussian (LQG) controller to track the desired trajectory given by the continuum deformation in the presence of disturbance and measurement noise. Results of simulated cooperative aerial payload transport in the presence of uncertainty illustrate the application of continuum deformation for coordinated transport through a narrow channel

Brane world models need low string scale

Models with large extra dimensions offer the possibility of the Planck scale being of order the electroweak scale, thus alleviating the gauge hierarchy problem. We show that these models suffer from a breakdown of unitarity at around three quarters of the low effective Planck scale. An obvious candidate to fix the unitarity problem is string theory. We therefore argue that it is necessary for the string scale to appear below the effective Planck scale and that the first signature of such models would be string resonances. We further translate experimental bounds on the string scale into bounds on the effective Planck scale

Classical Robustness of Quantum Unravellings

We introduce three measures which quantify the degree to which quantum systems possess the robustness exhibited by classical systems when subjected to continuous observation. Using these we show that for a fixed environmental interaction the level of robustness depends on the measurement strategy, or unravelling, and that no single strategy is maximally robust in all ways.Comment: 8 Pages, 2 figures, Version 2. Minor changes to wording for clarification and some references added. Accepted for publication in Europhysics Letter

Hydrogen-Related Conversion Processes of Ge-Related Point Defects in Silica Triggered by UV Laser Irradiation

The conversion processes of Ge-related point defects triggered in amorphous SiO2 by 4.7eV laser exposure were investigated. Our study has focused on the interplay between the (=Ge•-H) H(II) center and the twofold coordinated Ge defect (=Ge••). The former is generated in the post-irradiation stage, while the latter decays both during and after exposure. The post-irradiation decay kinetics of =Ge•• is isolated and found to be anti-correlated to the growth of H(II), at least at short times. From this finding it is suggested that both processes are due to trapping of radiolytic H0 at the diamagnetic defect site. Furthermore, the anti-correlated behavior is preserved also under repeated irradiation: light at 4.7eV destroys the already formed H(II) centers and restore their precursors =Ge••. This process leads to repeatability of the post-irradiation kinetics of the two species after multiple laser exposures. A comprehensive scheme of chemical reactions explaining the observed post-irradiation processes is proposed and tested against experimental data.Comment: 25 pages, 7 figures, submitted to Phys. Rev.

Analysis of Current and Potential Treatments for Chronic Lymphocytic Leukemia

Chronic Lymphocytic Leukemia (CLL) is one of the most common forms of adult leukemia in North Americans. However, it has been shown through the analysis of clinical studies and synopses of medical research that no current treatment indefinitely cures CLL or prolongs the life of CLL patients. Current CLL therapies are either symptomatic treatments (chemotherapy and immunotherapy) that do not improve complete remission rates or effective treatments that target the actual cancer but have excessive morbidity and toxicity rates (stem cell transplants). Conventional CLL treatments are inadequate according to the results of clinical trials and research of field experts. Potential fields of research (nanotechnology, gene therapy and phytotherapy) that show promise as CLL therapies according to the studies of researchers and scientists should be further examined. If a cure for CLL is to be found, the focus of treatment needs to move away from symptomatic relief toward the identification and remedy of the cause of the cancer

Hearts Torn Asunder: Trauma in the Civil War’s Final Campaign in North Carolina

In Hearts Torn Asunder: Trauma in the Civil War’s Final Campaign in North Carolina, author Earnest A. Dollar focuses...on the war\u27s impact on the soldiers and on the civilians caught between the two armies in a fresh look at...the war\u27s most significant remaining theater after Appomattox writes reviewer Jonathan M. Atkin

Reading William Gilmore Simms: Essays of Introduction to the Author’s Canon

Reading William Gilmore Simms: Essays of Introduction to the Author’s Canon presents the critical introductory essays written by twenty-four historians, literary scholars, and Southern specialists for the thirty-eight volumes that contain the works published during Simms’s lifetime