Salt encroachment : the 1974 saltland survey

It has long been recognised that the clearing of land for agriculture in the south western Australia is followed by the development of saline soils and streams. In 1955 and again in 1962, in conjunction with the annual statistical returns, farmers in Western Australia were asked to supply estimates of salt-affected land on their properties. In 1974 a further survey was conducted, in co-operation with the Australian Bureau of Statistics, using questions covering only the basic information. As the information is again available on a Shire basis a direct comparison can be made with the 1962 survey except for some high and low rainfall areas not included in 1962. Comparison of 1974 survey results with those for the 1962 saltland survey indicates both marked increases and decreases in various shires

Resonant Processes in a Frozen Gas

We present a theory of resonant processes in a frozen gas of atoms interacting via dipole-dipole potentials that vary as $r^{-3}$, where $r$ is the interatomic separation. We supply an exact result for a single atom in a given state interacting resonantly with a random gas of atoms in a different state. The time development of the transition process is calculated both on- and off-resonance, and the linewidth with respect to detuning is obtained as a function of time $t$. We introduce a random spin Hamiltonian to model a dense system of resonators and show how it reduces to the previous model in the limit of a sparse system. We derive approximate equations for the average effective spin, and we use them to model the behavior seen in the experiments of Anderson et al. and Lowell et al. The approach to equilibrium is found to be proportional to $\exp (-\sqrt{\gamma_{eq}t}$), where the constant $\gamma _{eq}$ is explicitly related to the system's parameters.Comment: 30 pages, 6 figure

Correcting the polarization effect in low frequency Dielectric Spectroscopy

We demonstrate a simple and robust methodology for measuring and analyzing the polarization impedance appearing at interface between electrodes and ionic solutions, in the frequency range from 1 to $10^6$ Hz. The method assumes no particular behavior of the electrode polarization impedance and it only makes use of the fact that the polarization effect dies out with frequency. The method allows a direct and un-biased measurement of the polarization impedance, whose behavior with the applied voltages and ionic concentration is methodically investigated. Furthermore, based on the previous findings, we propose a protocol for correcting the polarization effect in low frequency Dielectric Spectroscopy measurements of colloids. This could potentially lead to the quantitative resolution of the $\alpha$-dispersion regime of live cells in suspension

Some recent radio talks.

Light land development in the South - By A. S. WILD, Assistant Superintendent of Wheat Farming, Department of Agriculture. It is only since World War II ended that successful large scale development of light land near the south coast of this State has been undertaken, although the many millions of acres of treeless plain country throughout the agricultural areas have, for many years, presented a challenge to the pioneering ability of Western Australians. The use of hormones in viticulture - By L. T. JONES, Senior Plant Research Officer The discovery and proper use of plant hormones, or as they are more accurately termed, growth-regulating: substances, probably represents the greatest contribution which science has made to agriculture in the past few decades. It was the discovery by Kogl in 1934 that indole acetic acid was an active growth substance which led rapidly to the preparation and testing of large numbers of compounds of similar chemical structure and among these were found many substances which were very potent and also comparatively cheap to produce. Recent trends in viticulture in Western Australia - By W. R. JAMIESON, Viticulturist, Department of Agriculture, Perth Today I want to talk very briefly about some of the more recent trends in viticulture in this State. The commercial production of grapevines is centred mainly around the Swan Valley and as most of the suitable vineyard land in this area has been planted, growers are exploring avenues to increase the returns per acre. Methods of irrigation - By G. GAUNTLETT, Assistant Officer-in-Charge, Irrigation The success of an irrigation scheme depends on several factors. Important among these is the choice and design of the method to be adopted. There are two methods of irrigation, viz., surface and spray irrigation. Canker disease of Red-flowered gum - By W. P. CASS SMITH, B.Sc. (Agric), Government Plant Pathologist Of the many beautiful native plants in Western Australia, few are esteemed more than the red-flowered gum known botanically as Eucalyptus flcifolia. This shapely tree commences blossoming about Christmas time—and provides a magnificent display for several weeks—the blossom shades varying from dark red to pink. Why many beans grow crooked - By M. HARDIE, Vegetable Instructor Sometimes in the process of growing a crop, bean growers find a number of pods which, instead of being long and straight and suitable for marketing, are crooked or bent and quite unsuitable for sale unless beans are in very short supply. It is not unusual for a small number of pods to be affected in this way, generally at the tail-end of the crop, but occasionally the percentage may be high. When this happens the grower is often at a loss to account for his failure to grow a marketable crop. To the best of his ability he has followed methods which normally return a crop of first-grade pods and yet for some reason, his crop is an unpayable one and he is anxious to ascertain the cause. Salt land programme for Autumn - By T. C. STONEMAN, Adviser, Soil Conservation Service Now that summer is over and winter approaches, the time has come to decide what you\u27ll do with that salt problem on your farm. What you SHOULD do, will depend on how severely the area is affected. To make quite clear how the recommendations made by the Department of Agriculture can be applied I will deal with each degree of severity in turn. Orchard cover crops - By J. CRIPPS, Horticultural Adviser The sowing of a cover crop is one of those routine operations which the orchardist often undertakes without much thought, but it is an operation worthy of consideration. Lupin seed - By B. J. QUINLIVAN, B.Sc. (Agric), Botanist, Weeds and Seeds Branch The three types of lupins which we grow in this State are the New Zealand, the W.A. blue, and the yellow lupin. The first two types are very common, the New Zealand lupin being grown mainly in the South-West, while the W.A. lupin is grown over extensive areas of the central and northern wheatbelt, particularly on the sandier types of soil. Cereal rye will grow on wind-eroded areas - By G. H. BURVILL, Chief Plant Research Officer. Travelling around the wheatbelt, one often sees areas of sandy soil quite bare, A due to wind erosion. Surface soil blown from these patches has built up against fences, or as mounds in the nearby scrub. Many of the eroded places are quite small— perhaps less than an acre or only a few acres. But some are large, with one to three hundred acres of bare yellow sand. As much as two feet of soil has been blown from big areas. Autumn-winter feeding for the fat lamb flock - By N. DAVENPORT, Senior Adviser, Meat Production The autumn-winter period is the most important part of the year for the fat lamb crop from a feed point of view. It is important not only from the aspect of the wellbeing of the sheep, but also of the pasture. Pasture plants are living things, too, and they also require consideration and care for their development. When a new season pasture is kept hard grazed in those critical first few weeks of growth it cannot carry as many sheep over the season as one which is lightly stocked during that time. Plant diseases in the home garden - By W. P. CASS-SMITH, B.Sc. (Agric), Government Plant Pathologist Recently many home-gardeners have complained that plantings of vegetables or ornamentals are making unthrifty growth, in spite of liberal waterings and fertilisation. These symptoms are commonly caused by root-knot eelworm, a pest which has unfortunately become very widespread in the sandy soils adjacent to Perth, and in many other parts of this State. This eelworm parasite attacks the roots of many kinds of plants causing them to rot and to develop bead-like swellings or galls. As a result, the intake of plant food and water is restricted and stunting of the above-ground parts occurs. Principles of commercial beekeeping - By R. S. COLEMAN, R.D.A., Government Apiculturist We have many queries from small beekeepers, and from people who have never opened a hive, on how to break into full-time beekeeping. So it was thought that you would like to know just what are the principles of successful bee farming. Grasshoppers and locusts - By C. F. H. JENKINS, M.A., Government Entomologist Grasshoppers and locusts are among the most ancient enemies of mankind for they figured prominently in Biblical times, and periodically throughout the ages have devastated crops in all parts of the world. Acetonaemia in dairy cattle - By P. M. A. HARWOOD, M.R.C.V.S., Veterinary Officer Acetonaemia, more correctly known as ketosis is a metabolic disease. Unlike infectious diseases such as tuberculosis or mastitis, which are caused by microbes, metabolic diseases result from an upset in the normal bodily processes. Molybdenum for subterranean clover - By T. C. DUNNE, B.Sc. (Agric), Ph.D. (Calif.), Chief Plant Nutrition and Research Officer Subterranean clover is undoubtedly the most important pasture species in this State. Because it is a legume, it can make excellent growth on soils with a low nitrogen content. The nitrogen it needs is, of course, provided by bacteria which inhabit the nodules found on its roots. These bacteria provide nitrogen by taking it from the air and converting it to a form which can be used by the clover. However, it is now known that the bacteria can use the nitrogen of the air only if enough molybdenum is available to them. Cobalt deficiency in sheep and cattle - By C. R. TOOP, B.V.SC, Chief Veterinary Officer With the establishment of group settlements at Denmark after the first world war, it was observed that young cattle, although running on lush pastures, developed systems of unthriftness and wasting and usually died. Research conducted of Filmer and Underwood later revealed that this condition was caused by a deficiency of cobalt and that it could be cured and prevented by addition of this mineral to the diet. Cobalt deficiency has since been met with other parts of the State and was recently diagnosed in sheep at Mount Manypeaks

Churn, Baby, Churn: Strategic Dynamics Among Dominant and Fringe Firms in a Segmented Industry

This paper integrates and extends the literatures on industry evolution and dominant firms to develop a dynamic theory of dominant and fringe competitive interaction in a segmented industry. It argues that a dominant firm, seeing contraction of growth in its current segment(s), enters new segments in which it can exploit its technological strengths, but that are sufficiently distant to avoid cannibalization. The dominant firm acts as a low-cost Stackelberg leader, driving down prices and triggering a sales takeoff in the new segment. We identify a “churn” effect associated with dominant firm entry: fringe firms that precede the dominant firm into the segment tend to exit the segment, while new fringe firms enter, causing a net increase in the number of firms in the segment. As the segment matures and sales decline in the segment, the process repeats itself. We examine the predictions of the theory with a study of price, quantity, entry, and exit across 24 product classes in the desktop laser printer industry from 1984 to 1996. Using descriptive statistics, hazard rate models, and panel data methods, we find empirical support for the theoretical predictions

Sibling relationships and family functioning in siblings of early adolescents, adolescents and young adults with autism spectrum disorder

The purpose of the study was to investigate how family functioning (defined as the ability that family members hold to manage stressful events, and intimate and social relationships), the degree to which family members feel happy and fulfilled with each other (called family satisfaction), and the demographical characteristics of siblings (age and gender) impacted on sibling relationships. The Circumplex Model of Marital and Family Systems and Behavioral Systems constituted the theoretical frameworks that guided our study. Eighty-six typically developing adolescents and young adults having a sister or a brother with autism spectrum disorder were enrolled. Results indicated that the youngest age group (early adolescents) reported to engage more frequently in negative behaviors with their siblings with ASD than the two older age groups (middle adolescents and young adults). No significant differences were found among the three age groups regarding behaviors derived from attachment, caregiving and affiliative systems. Family satisfaction and age significantly predicted behaviors during sibling interactions. Suggestions on prevention and intervention programs were discussed in order to prevent parentification among typically developing siblings and decrease episodes of quarrels and overt conflicts between brothers and sisters with and without AS

Trapped Rydberg Ions: From Spin Chains to Fast Quantum Gates

We study the dynamics of Rydberg ions trapped in a linear Paul trap, and discuss the properties of ionic Rydberg states in the presence of the static and time-dependent electric fields constituting the trap. The interactions in a system of many ions are investigated and coupled equations of the internal electronic states and the external oscillator modes of a linear ion chain are derived. We show that strong dipole-dipole interactions among the ions can be achieved by microwave dressing fields. Using low-angular momentum states with large quantum defect the internal dynamics can be mapped onto an effective spin model of a pair of dressed Rydberg states that describes the dynamics of Rydberg excitations in the ion crystal. We demonstrate that excitation transfer through the ion chain can be achieved on a nanosecond timescale and discuss the implementation of a fast two-qubit gate in the ion chain.Comment: 26 pages, 9 figure

Re-inventing artisanal knowledge and practice: a critical review of innovation in a craft-based industry

This paper presents a critical review of the ways in which the specialised knowledge and working practices of craft-based industries have been transformed in the context of broader processes of industrialisation and global competition. The opening section makes the case for artisanal knowledge as a ‘Cinderella’ subject that remains important yet largely uncharted territory for innovation researchers. It is followed by a critical review of existing empirical and theoretical studies that have examined the reproduction and reinvention of artisanal knowledge. The review concludes that valuable insights remain obscured due to the way in which this literature is distributed across discrete disciplines with little evidence of cross-fertilisation or integration. Several common themes emerge, which provide the basis for an outline theoretical framework. The central arguments are illustrated with reference to a case-based analysis of the technological and social innovations that have taken place in English farmhouse cheesemaking over an extended period, from the pre-industrial era to the beginning of the present century. The concluding section considers how more nuanced understandings of artisanal knowledge and practice might enhance innovation theory and contribute to the continued flourishing of craft-based industries