THE SHIFTING SANDS OF SPACE SECURITY: THE POLITICS AND LAW OF THE PEACEFUL USES OF OUTER SPACE

This article argues that the content of the legal term “peaceful purposes,”as used in international space law is changing.  Peaceful Purposes as understood throughout the bulk of the Space Age has encompassed not only the UN Charter’s prohibitions on the use of force, but also a number of customary international law principles that enhanced it beyond mere non-aggression. Through an examination of state practice with regards to the military uses of outer space, this article concludes that the legal content of peaceful purposes is eroding towards an alignment with “non-aggressive” as understood in the law concerning the use of force.  Specifically, this article argues that geopolitical and technological changes are encouraging states to pursue disruption in the space environment rather than stability, and this has been matched with state practice and rhetoric that exhibits that states are moving toward more offensive, rather than defensive, stances in the space environment

Bright sand/dark dust: The identification of active sand surfaces on the Earth and Mars

Field studies and analysis of LANDSAT Thematic Mapper data in the Gran Desierto, Mexico may shed light on a technique to distinguish active from inactive (relict) sand surfaces. Active sand bodies in the study area are consistently brighter (by an average of 20%) at visual and near infrared wavelengths and darker at thermal infrared wavelengths than compositionally similar inactive sands. The reasons for the albedo difference between active and inactive sands are reviewed and the mixing model of Johnson et al. is examined for tracing the provenance of sands based on albedo and spectral variations. Portions of the wavelengths covered by the Mars Orbiter correspond to the Thematic Mapper data. The identification of active sands on Earth, with a priori knowledge of bulk composition and grain size distribution, may allow the remote mapping of active sand surfaces on Mars. In conjuction with thermal infrared remote sensing for composition, it may also provide a method for the remote determination of grain size distributions within sand/silt mixtures

Electron energy spectrum and the Berry phase in graphite bilayer

We emphasize that there exist four Dirac-type points in the electron-energy spectrum of a graphite bilayer near the point K of its Brillouin zone. One of the Dirac points is at the point K, and three Dirac points lie nearby. Each of these three points generates the Berry phase $\pi$, while the Dirac point at K gives the phase $-\pi$. It is these four points that determine the Berry phase in the bilayer. If an electron orbit surrounds all these points, the Berry phase is equal to $2\pi$.Comment: 4 pages, 2 figures, submitted to Phys. Rev. B ; expande

A particle system with explosions: law of large numbers for the density of particles and the blow-up time

Consider a system of independent random walks in the discrete torus with creation-annihilation of particles and possible explosion of the total number of particles in finite time. Rescaling space and rates for diffusion/creation/annihilation of particles, we obtain a stong law of large numbers for the density of particles in the supremum norm. The limiting object is a classical solution to the semilinear heat equation u_t =u_{xx} + f(u). If f(u)=u^p, 1<p \le 3, we also obtain a law of large numbers for the explosion time

Noncommutative geometry for three-dimensional topological insulators

We generalize the noncommutative relations obeyed by the guiding centers in the two-dimensional quantum Hall effect to those obeyed by the projected position operators in three-dimensional (3D) topological band insulators. The noncommutativity in 3D space is tied to the integral over the 3D Brillouin zone of a Chern-Simons invariant in momentum-space. We provide an example of a model on the cubic lattice for which the chiral symmetry guarantees a macroscopic number of zero-energy modes that form a perfectly flat band. This lattice model realizes a chiral 3D noncommutative geometry. Finally, we find conditions on the density-density structure factors that lead to a gapped 3D fractional chiral topological insulator within Feynman's single-mode approximation.Comment: 41 pages, 3 figure

Coordinate shift in the semiclassical Boltzmann equation and the anomalous Hall effect

We propose a gauge invariant expression for the side jump associated with scattering between particular Bloch states. Our expression for the side jump follows from the Born series expansion for the scattering T-matrix in powers of the strength of the scattering potential. Given our gauge invariant side jump expression, it is possible to construct a semiclassical Boltzmann theory of the anomalous Hall effect which expresses all previously identified contributions in terms of gauge invariant quantities and does not refer explicitly to off-diagonal terms in the density-matrix response.Comment: 6 pages, 1 fugure. submitted to PR

Development of a Bahiagrass \u3cem\u3ePaspalum Notatum\u3c/em\u3e Flugge With Increased Short-Day Biomass

Low herbage productivity of subtropical grasses during the short-day winter months of October through to March can place a severe burden on livestock producers in Southeastern U.S. Researchers at the University of Florida (Sinclair et al., 2001) hypothesised that the decrease in forage production might result from physiological dormancy induced by short day length. A study using artificial lights to extend the day length demonstrated that maintaining the day length at 15 hr during the short-day length period increased \u27Pensacola\u27 bahiagrass P. notatum Flugge saure Parodi forage yield 122% when compared with normal photoperiod (Mislevy et al., 2001). A Pensacola-derived bahiagrass population was selected for increased vegetative growth under short-day length using restricted recurrent phenotypic selection for three cycles (UF Cycle 3) to increase forage yield. Plants that comprise this population were less sensitive to short photoperiod and produced increased forage mass during the short days. The objective of this clipping study was to evaluate forage production and forage nutritive value of UF Cycle 3 compared with selected standard entries during short and long day length periods

Hydrophobic gating of mechanosensitive channel of large conductance evidenced by single-subunit resolution

Mechanosensitive (MS) ion channels are membrane proteins that detect and respond to membrane tension in all branches of life. In bacteria, MS channels prevent cells from lysing upon sudden hypoosmotic shock by opening and releasing solutes and water. Despite the importance of MS channels and ongoing efforts to explain their functioning, the molecular mechanism of MS channel gating remains elusive and controversial. Here we report a method that allows single-subunit resolution for manipulating and monitoring “mechanosensitive channel of large conductance” from Escherichia coli. We gradually changed the hydrophobicity of the pore constriction in this homopentameric protein by modifying a critical pore residue one subunit at a time. Our experimental results suggest that both channel opening and closing are initiated by the transmembrane 1 helix of a single subunit and that the participation of each of the five identical subunits in the structural transitions between the closed and open states is asymmetrical. Such a minimal change in the pore environment seems ideal for a fast and energy-efficient response to changes in the membrane tension.