Primer for the Transportable Applications Executive

The Transportable Applications Executive (TAE), an interactive multipurpose executive that provides commonly required functions for scientific analysis systems, is discussed. The concept of an executive is discussed and the various components of TAE are presented. These include on-line help information, the use of menus or commands to access analysis programs, and TAE command procedures

Scaling and Duality in Semi-exclusive Processes

We discuss extending scaling and duality studies to semi-exclusive processes. We show that semi-exclusive hard pion photoproduction should exhibit scaling behavior in kinematic regions where the photon and pion both interact directly with the same quark. We show that such kinematic regions exist. We also show that the constancy with changing momentum transfer of the resonance peak/scaling curve ratio, familiar for many resonances in deep inelastic scattering, is also expected in the semi-exclusive case.Comment: 8 pages, 4 figures, submitted to Phys.Rev.

Principal sources and dispersal patterns of suspended particulate matter in nearshore surface waters of the northeast Pacific Ocean and the Hawaiian Islands

The author has identified the following significant results. ERTS-1 multispectral scanner imagery of the nearshore surface waters of the Northeast Pacific Ocean is proving to be a useful tool for determining source and dispersal of suspended particulate matter. The principal sources of the turbid water, seen best on the green and red bands, are river and stream effluents and actively eroding coastlines; secondary sources are waste effluents and production of planktonic organisms, but these may sometimes be masked by the very turbid plumes of suspended sediment being discharged into the nearshore zone during times of high river discharge. The configuration and distribution of the plumes of turbid water also can be used to infer near-surface current directions. Comparison of imagery of the nearshore water off the northern California coast from October 1972 and January 1973 shows a reversal of the near-surface currents, from predominantly south-setting in the fall (California Current) to north-setting in the winter (Davidson Current)

Predictability of Self-Organizing Systems

We study the predictability of large events in self-organizing systems. We focus on a set of models which have been studied as analogs of earthquake faults and fault systems, and apply methods based on techniques which are of current interest in seismology. In all cases we find detectable correlations between precursory smaller events and the large events we aim to forecast. We compare predictions based on different patterns of precursory events and find that for all of the models a new precursor based on the spatial distribution of activity outperforms more traditional measures based on temporal variations in the local activity.Comment: 15 pages, plain.tex with special macros included, 4 figure

Word Processors with Line-Wrap: Cascading, Self-Organized Criticality, Random Walks, Diffusion, Predictability

We examine the line-wrap feature of text processors and show that adding characters to previously formatted lines leads to the cascading of words to subsequent lines and forms a state of self-organized criticality. We show the connection to one-dimensional random walks and diffusion problems, and we examine the predictability of catastrophic cascades.Comment: 6 pages, LaTeX with RevTeX package, 4 postscript figures appende

The Expanded Very Large Array

In almost 30 years of operation, the Very Large Array (VLA) has proved to be a remarkably flexible and productive radio telescope. However, the basic capabilities of the VLA have changed little since it was designed. A major expansion utilizing modern technology is currently underway to improve the capabilities of the VLA by at least an order of magnitude in both sensitivity and in frequency coverage. The primary elements of the Expanded Very Large Array (EVLA) project include new or upgraded receivers for continuous frequency coverage from 1 to 50 GHz, new local oscillator, intermediate frequency, and wide bandwidth data transmission systems to carry signals with 16 GHz total bandwidth from each antenna, and a new digital correlator with the capability to process this bandwidth with an unprecedented number of frequency channels for an imaging array. Also included are a new monitor and control system and new software that will provide telescope ease of use. Scheduled for completion in 2012, the EVLA will provide the world research community with a flexible, powerful, general-purpose telescope to address current and future astronomical issues.Comment: Added journal reference: published in Proceedings of the IEEE, Special Issue on Advances in Radio Astronomy, August 2009, vol. 97, No. 8, 1448-1462 Six figures, one tabl

Spin Waves in Striped Phases

In many antiferromagnetic, quasi-two-dimensional materials, doping with holes leads to "stripe" phases, in which the holes congregate along antiphase domain walls in the otherwise antiferromagnetic texture. Using a suitably parametrized two-dimensional Heisenberg model on a square lattice, we study the spin wave spectra of well-ordered spin stripes, comparing bond-centered antiphase domain walls to site-centered antiphase domain walls for a range of spacings between the stripes and for stripes both aligned with the lattice ("vertical") and oriented along the diagonals of the lattice ("diagonal"). Our results establish that there are qualitative differences between the expected neutron scattering responses for the bond-centered and site-centered cases. In particular, bond-centered stripes of odd spacing generically exhibit more elastic peaks than their site-centered counterparts. For inelastic scattering, we find that bond-centered stripes produce more spin wave bands than site-centered stripes of the same spacing and that bond-centered stripes produce rather isotropic low energy spin wave cones for a large range of parameters, despite local microscopic anisotropy. We find that extra scattering intensity due to the crossing of spin wave modes (which may be linked to the "resonance peak" in the cuprates) is more likely for diagonal stripes, whether site- or bond-centered, whereas spin wave bands generically repel, rather than cross, when stripes are vertical.Comment: 12 pages, 12 figures, for some high-res.pics, see http://physics.bu.edu/~yaodx/spinwave/spinw.htm

Use of thermal inertia determined by HCMM to predict nocturnal cold prone areas in Florida

Registered data sets were used to develop qualititative temperature and delta T maps of a band across north Florida and across south Florida for use with Carlson's boundary layer energy model balance model. Thermal inertia and moisture availability computations for north Florida are being used to investigate model sensitivity and to evaluate input parameters. Temperature differences of day-night HCMM overpasses clearly differentiate wetlands and uplands areas

Optical Response for the d-density wave model

We have calculated the optical conductivity and the Raman response for the d-density wave model, proposed as a possible explanation for the pseudogap seen in high Tc cuprates. The total optical spectral weight remains approximately constant on opening of the pseudogap for fixed temperature. This occurs because there is a transfer of weight from the Drude peak to interband transitions across the pseudogap. The interband peak in the optical conductivity is prominent but becomes progressively reduced with increasing temperature, with impurity scattering, which distributes it over a larger energy range, and with ineleastic scattering which can also shift its position, making it difficult to have a direct determination of the value of the pseudogap. Corresponding structure is seen in the optical scattering rate, but not necessarily at the same energies as in the conductivity.Comment: 14 pages, 15 figures, final revised version published in PR