Effects of the Maryland hydraulic clam dredge on populations of the soft-shell clam, Mya arenaria: final contract report

Final report on a three year study designed to investigate the effects of the Maryland hydraulic escalator clam dredge on populations and recruitment of the soft-shell clam, Mya arenaria. Experimental plots were established in the Potomac river, Maryland, and were dredged ina commerical manner by removing only legal size clams. quarterly samples were taken in the experimental and control plots by means of a van Veen grab for juvenile clams and the hydraulic dredge for older, deeper burrowing clams. Sediment samples were taken at selected periods for organic carbon and grain size analysis. Clams were separated into two size-groups. (PDF contains 38 pages

The RoboFlag SURF competition: results, analysis, and future work

The culmination of the 2002 RoboFlag Summer Undergraduate Research Fellowship program, jointly operated between California Institute of Technology and Cornell University, was a final competition between two teams of three undergraduate researchers. After ten weeks of preparation, Team Pasadena defeated Team Ithaca in two of the three final games. This paper provides the detailed results of the competition, an analysis of the competition, and reviews the future work

Handbook on passive thermal control coatings

A handbook of passive thermal control surfaces data pertaining to the heat transfer requirements of spacecraft is presented. Passive temperature control techniques and the selection of control surfaces are analyzed. The space environmental damage mechanisms in passive thermal control surfaces are examined. Data on the coatings for which technical information is available are presented in tabular form. Emphasis was placed on consulting only those references where the experimental simulation of the space environment appeared to be more appropriate

Loss-tolerant operations in parity-code linear optics quantum computing

A heavy focus for optical quantum computing is the introduction of error-correction, and the minimisation of resource requirements. We detail a complete encoding and manipulation scheme designed for linear optics quantum computing, incorporating scalable operations and loss-tolerant architecture.Comment: 8 pages, 6 figure

Efficient Parity Encoded Optical Quantum Computing

We present a linear optics quantum computation scheme with a greatly reduced cost in resources compared to KLM. The scheme makes use of elements from cluster state computation and achieves comparable resource usage to those schemes while retaining the circuit based approach of KLM

Charge centers in CaF2_2: Ab initio calculation of elementary physical properties

Charge centers in ionic crystals provide a channel for elementary interaction between electromagnetic radiation and the lattice. We calculate the electronic ground state energies which are needed to create a charge center -- namely a $F$- and a $H$-center. In well agreement with common understanding the $F$-center results in being accompanied by a small lattice distortion whereas the $H$-center is accompanied by a very large lattice deformation. Opposite to the common understanding the additional positive charge in the charge center results rather to be localized on a F$_4^{3-}$ complex than on a F$_2^-$-complex. From the ground states of the charge centers we derive binding energies, diffusion barriers and agglomeration energies for $M$-center formation. These microscopic quantities are of fundamental interest to understand the dynamic processes which are initiated if the crystals interact with extreme intense deep ultra violet radiation. We further derive the equilibrium concentrations of charge centers in grown crystals.Comment: to appear in Phys. Rev. B in Aug. 2006, 11 Fig

A Search for Intrinsic Polarization in O Stars with Variable Winds

New observations of 9 of the brightest northern O stars have been made with the Breger polarimeter on the 0.9~m telescope at McDonald Observatory and the AnyPol polarimeter on the 0.4~m telescope at Limber Observatory, using the Johnson-Cousins UBVRI broadband filter system. Comparison with earlier measurements shows no clearly defined long-term polarization variability. For all 9 stars the wavelength dependence of the degree of polarization in the optical range can be fit by a normal interstellar polarization law. The polarization position angles are practically constant with wavelength and are consistent with those of neighboring stars. Thus the simplest conclusion is that the polarization of all the program stars is primarily interstellar. The O stars chosen for this study are generally known from ultraviolet and optical spectroscopy to have substantial mass loss rates and variable winds, as well as occasional circumstellar emission. Their lack of intrinsic polarization in comparison with the similar Be stars may be explained by the dominance of radiation as a wind driving force due to higher luminosity, which results in lower density and less rotational flattening in the electron scattering inner envelopes where the polarization is produced. However, time series of polarization measurements taken simultaneously with H-alpha and UV spectroscopy during several coordinated multiwavelength campaigns suggest two cases of possible small-amplitude, periodic short-term polarization variability, and therefore intrinsic polarization, which may be correlated with the more widely recognized spectroscopic variations.Comment: LaTeX2e, 22 pages including 11 tables; 12 separate gif figures; uses aastex.cls preprint package; accepted by The Astronomical Journa