Capital,the state and rural land holdings: the example of the pastoral industry in the Northern Territory

Large capital interests have a long history of ownership of rural land in Australia. There have been many changes in this kind of ownership in recent decades. The rationale for various forms of ownership of large leasehold areas in the Northern Territory is presented. New financial structures operating in local and international capital markets and the opportunities presented by the state are important parts of this rationale.     

Observing Magnetic Fields in Star-Forming Regions

Magnetic field strengths and directions can be estimated using many different observational techniques that span a wide range of wavelengths. Each observational method favours different regimes of scale size, density and other physical conditions. The available techniques and their ranges of applicability are briefly described and the current status of observations is reviewed, with particular emphasis on high-resolution observations of star-forming regions.     

Hydrologic,geomorphic and climatic processes controlling willow establishment in a montane ecosystem

Willow communities dominate mid‐elevation riparian areas throughout the Rocky Mountains of North America. However, many willow stands are rapidly declining in aerial cover and individual plants in stature. A poor understanding of the processes that control willow establishment hinders identifying the causes of this decline. We analysed the processes that have facilitated or limited willow establishment over the last half of the 20th century on two large floodplains in Rocky Mountain National Park in Colorado by addressing two questions: (1) How does hydrologic regime control willow establishment on different fluvial landforms? (2) How might climate‐driven variations in hydrologic regime affect future willow establishment? We precisely aged willows on the three most common fluvial landforms, stream point bars, drained beaver ponds, and abandoned channels, and statistically related establishment dates to patterns of annual stream peak flow. The role of peak flow on willow establishment varied significantly by landform. Willow recruitment had occurred nearly every year on point bars. In former beaver complexes, most willows had established following dam breaches, whereas willows had established on abandoned channels for several years following channel avulsion. Establishment on point bars and abandoned channels was driven by peak flows of 2‐ to 5‐year return intervals, whereas in abandoned beaver ponds most establishment was associated with flow events of >5‐year return interval. Models of climate change suggest that temperatures will increase and precipitation seasonality will shift over the coming decades in the Rocky Mountains, leading to earlier spring runoff, lower summer and fall flows, decreased snowpack and decreased soil moisture. Such changes are likely to diminish opportunities for willow establishment. Copyright © 2005 John Wiley & Sons, Ltd.     

Hydrogen–deficient stars: recent work at the SAAO

A brief review is given of some of the recent SAAO observational programmes concerning various types of Hydrogen-deficient stars with some attempt to relate this work to general research in the field. The review covers R Coronæ Borealis (RCB) stars, Hydrogen-deficient Carbon (HdC) stars, and Extreme Helium (EHe) stars in the Carbon-rich group and AM CVn stars and the (apparently) unique star V652 Her in the Carbon-normal group.     

Photometry: New techniques,an introduction

In most fields of observational astronomy, the new techniques we have now and are developing offer great potentials for more and better data, and thus to increased understanding of the universe about us. Photometry, as perhaps the most fundamental of all the observational tools, is no exception. The next years will be most exciting, but we must always be aware of the potential pitfalls involved with new technology. In fact, the new technologies must be handled with great care in order to insure that our data is really first class. New generation small telescopes can be a great asset, offering great complementarity to the new large telescopes and to space astronomy.Operated by AURA, Inc. under cooperative agreement with the National Science Foundation, Washington D.C.     

Antarctic Dry Valleys and indigenous weathering in Mars meteorites: Implications for water and life on Mars

The Dry Valleys of Antarctica are an excellent analog of the environment at the surface of Mars. Soil formation histories involving slow processes of sublimation and migration of water-soluble ions in polar desert environments are characteristic of both Mars and the Dry Valleys. At the present time, the environment in the Dry Valleys is probably the most similar to that in the mid-latitudes on Mars although similar conditions may be found in areas of the polar regions during their respective Mars summers. It is thought that Mars is currently in an interglacial period, and that subsurface water ice is sublimating poleward. Because the Mars sublimation zones seem to be the most similar to the Antarctic Dry Valleys, the Dry Valleys-type Mars climate is migrating towards the poles. Mars has likely undergone drastic obliquity changes, which means that the Dry Valleys analog to Mars may be valid for large parts of Mars, including the polar regions, at different times in geologic history. Dry Valleys soils contain traces of silicate alteration products and secondary salts much like those found in Mars meteorites. A martian origin for some of the meteorite secondary phases has been verified previously; it can be based on the presence of shock effects and other features which could not have formed after the rocks were ejected from Mars, or demonstrable modification of a feature by the passage of the meteorite through Earth's atmosphere (proving the feature to be pre-terrestrial). The martian weathering products provide critical information for deciphering the near-surface history of Mars. Definite martian secondary phases include Ca-carbonate, Ca-sulfate, and Mg-sulfate. These salts are also found in soils from the Dry Valleys of Antarctica. Results of earlier Wright Valley work are consistent with what is now known about Mars based on meteorite and orbital data. Results from recent and current Mars missions support this inference. Aqueous processes are active even in permanently frozen Antarctic Dry Valleys soils, and similar processes are probably also occurring on Mars today, especially at the mid-latitudes. Both weathering products and life in Dry Valleys soils are distributed heterogeneously. Such variations should be taken into account in future studies of martian soils and also in the search for possible life on Mars.     

Preliminary Photometric Results for the 2003 Eclipse of Ee Cep

We report multicolour photometric observations of the 2003 eclipse of the long-period (5.6 yr) eclipsing binary EE Cep. Measurements were obtained with ten telescopes at eight observatories in four countries. In most cases, UBV(RI)_C broad band filters have been used. The light curve shape shows that the obscuring body is an almost dark disk around a low-luminosity central object. However, variations of the colour indices during the eclipse indicate that the obscuring body emits a considerable amount of radiation in the near infrared.