A prototype DSN X/S-band feed: DSS 13 application status

A prototype X/S-band common aperture horn feed for future use at various DSN sites and the Network Consolidation Program is discussed. The final design and fabrication of the second generation feedhorn and combiner is dealt with. The results of the measurements obtained with the second generation, full scale feed configuration are presented

On the Measure in Simplicial Gravity

Functional measures for lattice quantum gravity should agree with their continuum counterparts in the weak field, low momentum limit. After showing that the standard simplicial measure satisfies the above requirement, we prove that a class of recently proposed non-local measures for lattice gravity do not satisfy such a criterion, already to lowest order in the weak field expansion. We argue therefore that the latter cannot represent acceptable discrete functional measures for simplicial geometries.Comment: LaTeX, 15 pages, 2 figure

CO on Ru(001): Formation and dissolution of islands of CO at low coverages

The present paper deals with the benefits and difficulties of using ion scattering spectroscopy as a spectrometric technique

Notes on \u3ci\u3eChrysomelobia Labidomerae\u3c/i\u3e (Acari: Heterostigmata: Podapolipidae), Parasites of \u3ci\u3eLabidomera Clivicollis\u3c/i\u3e (Coleoptera: Chrysomelidae) in Michigan and Wisconsin

Chrysomelobia labidomerae Eickwort, ectoparasitic mite of chrysomelid beetles, is reported from 11 Wisconsin counties, from 16 of 82 adult Labidomera clivicollis (Kirby) beetles wild-caught in Wisconsin, and from 27 of 141 presumably wild-caught L. clivicollis beetles from 13 Michigan counties. Wisconsin beetles harboring C. labidomerae were found in dry to wet-mesic, open habitats. A distribution map and comments are presented

A probability-based approach to setting annual catch levels.

The requirement of setting annual catch limits to prevent overfishing has been added to the Magnuson-Stevens Fishery Conservation and Management Reauthorization Act of 2006 (MSRA). Because this requirement is new, a body of applied scientific practice for deriving annual catch limits and accompanying targets does not yet exist. This article demonstrates an approach to setting levels of catch that is intended to keep the probability of future overfishing at a preset low level. The proposed framework is based on stochastic projection with uncertainty in population dynamics. The framework extends common projection methodology by including uncertainty in the limit reference point and in management implementation, and by making explicit the risk of overfishing that managers consider acceptable. The approach is illustrated with application to gag (Mycteroperca microlepis), a grouper that inhabits the waters off the southeastern United States. Although devised to satisfy new legislation of the MSRA, the framework has potential application to any fishery where the management goal is to limit the risk of overfishing by controlling catch

Start-to-end modelling of a mode-locked optical klystron free electron laser amplifier

A free electron laser (FEL) in a mode-locked optical klystron (MLOK) configuration is modelled using start-to-end simulations that simulate realistic electron beam acceleration and transport before input into a full three-dimensional FEL simulation code. These simulations demonstrate that the MLOK scheme is compatible with the present generation of radiofrequency accelerator designs. A train of few-optical cycle pulses is predicted with peak powers similar to those of the equivalent conventional FEL amplifier. The role of electron beam energy modulation in these results is explained and the limitations of some simulation codes discussed. It is shown how seeding the FEL interaction using a High Harmonic seed laser can improve the coherence properties of the output

Comparison of Compression Schemes for CLARA

CLARA (Compact Linear Advanced Research Accelerator)at Daresbury Laboratory is proposed to be the UK's national FEL test facility. The accelerator will be a ~250 MeV electron linac capable of producing short, high brightness electron bunches. The machine comprises a 2.5cell RF photocathode gun, one 2 m and three 5 m normal conducting S-band (2998MHz) accelerating structures and a variable magnetic compression chicane. CLARA will be used as a test bed for novel FEL configurations. We present a comparison of acceleration and compression schemes for the candidate machine layout.Comment: 3 pages, 5 figures, IPAC 201

Gravitational Wilson Loop in Discrete Quantum Gravity

Results for the gravitational Wilson loop, in particular the area law for large loops in the strong coupling region, and the argument for an effective positive cosmological constant discussed in a previous paper, are extended to other proposed theories of discrete quantum gravity in the strong coupling limit. We argue that the area law is a generic feature of almost all non-perturbative lattice formulations, for sufficiently strong gravitational coupling. The effects on gravitational Wilson loops of the inclusion of various types of light matter coupled to lattice quantum gravity are discussed as well. One finds that significant modifications to the area law can only arise from extremely light matter particles. The paper ends with some general comments on possible physically observable consequences.Comment: 39 pages, 10 figure

Cooling system for removing metabolic heat from an hermetically sealed spacesuit

An improved cooling and ventilating system is described for removing metabolic heat, waste gases and water vapor generated by a wearer of an hermetically sealed spacesuit. The cooling system was characterized by a body suit, having a first circuit for simultaneously establishing a cooling flow of water through the thorax and head sections of the body suit. Circulation patches were included mounted in the thorax section and head section of the body suit. A second circuit for discharing a flow of gas throughout the spacesuit and a disconnect unit for coupling the circuits with a life support system externally related to the spacesuit were provided

SeaSat-A Satellite Scatterometer Mission Summary and Engineering Assessment Report

The SeaSat-A satellite was launched on June 26, 1978 and operated in orbit through October 9, 1978. The SeaSat-A satellite scatterometer ocean surface wind field sensor began taking data on July 10, 1978 with virtually continuous operation for 95-1/2 days. A review of mission events significant to the scatterometer and a report on the hardware and software engineering assessment are presented