An HI census of Loose Groups of Galaxies

We present results from our Parkes Multibeam HI survey of 3 loose groups of galaxies that are analogous to the Local Group. This is a survey of groups containing only spiral galaxies with mean separations of a few hundred kpc, and total areas of approximately 1 sq. Mpc; groups similar to our own Local Group. We present a census of the HI-rich objects in these groups down to an M(HI), 1-sigma sensitivity ~7x10^5 M(sun), as well as the detailed properties of these detections from follow-up Compact Array observations. We found 7 new HI-rich members in the 3 groups, all of which have stellar counterparts and are, therefore, typical dwarf galaxies. The ratio of low-mass to high-mass gas-rich galaxies in these groups is less than in the Local Group meaning that the ``missing satellite'' problem is not unique. No high-velocity cloud analogs were found in any of the groups. If HVCs in these groups are the same as in the Local Group, this implies that HVCs must be located within ~300-400 kpc of the Milky Way.Comment: 6 pages, to appear in the ASP proceedings of IAU Symposium 217, "Recycling intergalactic and interstellar matter", eds. Pierre-Alain Duc, Jonathan Braine, Elias Brink

Investing in Biodiversity Conservation: Proceedings of a Workshop

This document presents the proceedings of a one-day Workshop on Investing in Biodiversity Conservation held at the Inter-American Development Bank in Washington, D.C., on October 28, 1996. The first part of the workshop was dedicated to the presentation of key topics on biodiversity financing by five leaders in the field. The second part of the workshop was dedicated to a discussion and exchange of ideas on the role of the IDB in investing in biodiversity conservation. Three main recommendations emerged: 1) The Bank should prepare a report on on its experience in biodiversity projects and development programs with biodiversity components; 2) A task force should be formed to work on a bio-diversity policy or strategy; 3) IDB staff should be trained to understand the biodiversity concept and its implications in project preparation and implementation.Environmental Policy, Biodiversity, Natural Resources Management

Servomotor and Controller Having Large Dynamic Range

A recently developed micro-commanding rotational-position-control system offers advantages of less mechanical complexity, less susceptibility to mechanical resonances, less power demand, less bulk, less weight, and lower cost, relative to prior rotational-position-control systems based on stepping motors and gear drives. This system includes a digital-signal- processor (DSP)-based electronic controller, plus a shaft-angle resolver and a servomotor mounted on the same shaft. Heretofore, micro-stepping has usually been associated with stepping motors, but in this system, the servomotor is micro-commanded in response to rotational-position feedback from the shaft-angle resolver. The shaft-angle resolver is of a four-speed type chosen because it affords four times the resolution of a single-speed resolver. A key innovative aspect of this system is its position-feedback signal- conditioning circuits, which condition the resolver output signal for multiple ranges of rotational speed. In the preferred version of the system, two rotational- speed ranges are included, but any number of ranges could be added to expand the speed range or increase resolution in particular ranges. In the preferred version, the resolver output is conditioned with two resolver-to-digital converters (RDCs). One RDC is used for speeds from 0.00012 to 2.5 rpm; the other RDC is used for speeds of 2.5 to 6,000 rpm. For the lower speed range, the number of discrete steps of RDC output per revolution was set at 262,144 (4 quadrants at 16 bits per quadrant). For the higher speed range, the number of discrete steps per revolution was set at 4,096 (4 quadrants at 10 bits per quadrant)

On the validity of the reduced Salpeter equation

We adapt a general method to solve both the full and reduced Salpeter equations and systematically explore the conditions under which these two equations give equivalent results in meson dynamics. The effects of constituent mass, angular momentum state, type of interaction, and the nature of confinement are all considered in an effort to clearly delineate the range of validity of the reduced Salpeter approximations. We find that for $J\not{\hspace*{-1.0mm}=}0$ the solutions are strikingly similar for all constituent masses. For zero angular momentum states the full and reduced Salpeter equations give different results for small quark mass especially with a large additive constant coordinate space potential. We also show that $\frac{1}{m}$ corrections to heavy-light energy levels can be accurately computed with the reduced equation.Comment: Latex (uses epsf macro), 24 pages of text, 12 postscript figures included. Slightly revised version, to appear in Phys. Rev.

On the instantaneous Bethe-Salpeter equation

We present a systematic algebraic and numerical investigation of the instantaneous Bethe-Salpeter equation. Emphasis is placed on confining interaction kernels of the Lorentz scalar, time component vector, and full vector types. We explore stability of the solutions and Regge behavior for each of these interactions, and conclude that only time component vector confinement leads to normal Regge structure and stable solutions.Comment: Latex (uses epsf macro), 26 pages of text, 12 postscript figures included

The Baryonic Tully Fisher Relation

We validate the baryonic Tully Fisher (BTF) relation by exploring the Tully Fish er (TF) and BTF properties of optically and HI-selected disk galaxies. The data includes galaxies from: Sakai et al. (2000) calibrator sample; McGaugh et al. (2000: MC2000) I-band sample; and 18 newly acquired HI-selected field dwarf galaxies observed with the ANU 2.3m telescope and the ATNF Parkes telescope from Gurovich's thesis sample (2005). As in MC2000, we re-cast the TF and BTF relations as relationships between baryo n mass and W_{20}. First we report some numerical errors in MC2000. Then, we c alculate weighted bi-variate linear fits to the data, and finally we compare the fits of the intrinsically fainter dwarfs with the brighter galaxies of Sakai et al. (2000). With regards to the local calibrator disk galaxies of Sakai et al. (2000), our results suggest that the BTF relation is indeed tighter than the T F relation and that the slopes of the BTF relations are statistically flatter th an the equivalent TF relations. Further, for the fainter galaxies which include the I-band MCG2000 and HI-selected galaxies of Gurovich's thesis sample, we calc ulate a break from a simple power law model because of what appears to be real c osmic scatter. Not withstanding this point, the BTF models are marginally better models than the equivalent TF ones with slightly smaller reduced chi^2.Comment: 3 pages, 3 figs, refereed conference proceeding based on an invited talk at the Structure and Dynamics in the Local Universe, a Sydney workshop to honour Brent Tully's 60th birthday. To appear in Publications of the Astronomical Society of Australia, ed. J. Bland-Hawthor