The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.

Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.

Foliar abscission induced by mist blower applications of endothall [7-oxabicyclo(2,2,1)heptane-2,3-dicarboxylic acid] combined with ethephon [(2-chloroethyl)phosphonic acid] occurred within 14 days on six field-grown deciduous species. Refoliation was essentially complete after one dormant season except on pin oak (Quercus palustris Muenchh.), which exhibited shoot damage from May and June treatments. Abscission did not occur on coniferous species. Effective doses ranged from 150 to 2,400 μg/ml endothall with 4,800 μg/ml ethephon. In greenhouse experiments on white ash (Fraxinus americana L.), the most effective levels of surfactant with endothall/ethephon ranged from 0.5 to 1.3%, and a spray volume as low as one-quarter runoff gave adequate coverage.

Providing magnetite nanoparticles with saccharide coatings has been found to significantly increase the interactions of the nanoparticles with cells. Glucose (Glc) or N-acetylglucosamine (GlcNAc) coated magnetic nanoparticles (MNPs) were used to magnetically label 3T3 fibroblast cells, and the response of the labelled cells to external magnetic fields was studied. It was found that cells incubated with Glc- or GlcNAc-coated nanoparticles were much more likely to move towards an external magnet than those incubated with uncoated nanoparticles. Furthermore, cells in suspension moved much faster than those in contact with the surface of polystyrene well plates, with stronger magnets increasing the speed of movement. Cells that were adhering to the floor of the cell culture well and did not move in the x-y plane could still be rotated about the z-axis by moving the external magnet around the cell.

The Cosmology Distinction Course is a new one-year course to be introduced for Year 12 candidates in the 1994 Higher School Certificate examinations in NSW. It is one of three challenging courses of study that will enrich the HSC for talented students who accelerate and complete part of the HSC one year early. The courses will be taught through distance learning and will include residential seminars. They will be implemented on behalf of the Board of Studies by Charles Sturt University and the University of New England.

The Cosmology Course is organised into nine modules of course work covering historical and social aspects of cosmology, observational techniques, key observations and the various models developed—Newtonian, de Sitter, Friedmann, Lemaitre, steady-state, quasi-steady-state and big bang. Assessment will be through assignments, exams and a major project.

As the first Distinction Course in a scientific area, the Cosmology Course represents an exciting and important educational initiative that needs the cooperation of NSW astronomers and, in return, promises to benefit the astronomical and general scientific community in Australia.

Adult plaice (Pleuronectes platessa L.) in the southern North Sea use selective tidal stream transport to migrate between their summer feeding grounds and winter spawning grounds. The fish come up into midwater when the tidal stream is flowing in one direction, but remain on the bottom when it is flowing in the opposite direction. This behaviour can theoretically save energy, which can be used for growth or reproduction. Alternatively, it may provide a transport system by means of which fish that have no ability to navigate over long distances can be conveyed reliably between their feeding grounds and spawning grounds.

The multi-dimensional structure of weak, energetic-particle-modified shocks is investigated by means of appropriate perturbation techniques. The time-dependent shock-structure equation is found to be a generalized form of the well-known one-dimensional Burgers equation, whose steady state, in the absence of cosmic rays, is shown to be related to an equation modelling steady transonic flow in several dimensions. The time-dependent (1 + 2)- and (1 + 3)-dimensional Burgers equations are integrated exactly by means of Hirota's technique for one-shock solutions. On the basis of the exact solutions, a discussion relating the various length scales associated with the shock is presented.

The objectives and management policy of an experimental farm for studies on the sugar beet crop are described. Farm yields of sugar beet and cereals are discussed in relation to yields in experiments and on a national scale. Some aspects of experimental accuracy and design are considered.

Forty-three near-isogenic lines (NILs) of white clover (Trifolium repens), derived from four parental self-compatible genotypes containing the rare self-fertility allele, were inoculated with the arbuscular mycorrhizal fungus Glomus mossae. Plant growth response (shoot and root weight and root length), shoot P uptake and mycorrhizal root infection rates were recorded 12 weeks after inoculation. There was generally a high degree of variation between individual lines in all recorded parameters. The most sensitive indicator of plant response to mycorrhizal infection was root length with almost half of all lines showing significant responses (in most cases a decrease in root length). Shoot weight was significantly different between mycorrhizal and nonmycorrhizal plants in nine lines. Parental genotype significantly affected both plant response to mycorrhiza as well as mycorrhizal infection rates. The results suggest that the NILs will prove useful for further studies to elucidate the molecular genetic control of the symbiosis and inform plant breeding strategies of this agronomically important species.

A new approach, the propagating-source method, is introduced to solve the time-dependent Boltzmann equation. The method relies on the decomposition of the particle distribution function into scattered and unscattered particles. It is assumed in this paper that the particles are transported in a constant-velocity spherically expanding supersonic flow (such as the solar wind) in the presence of a radial magnetic field. Attention too has been restricted to very fast particles. The present paper addresses only large-angle scattering, which is modelled as a BGK relaxation time operator. A subsequent paper (Part 2) will apply the propagating-source method to a small-angle quasilinear scattering operator. Initially, we consider the simplest form of the BGK Boltzmann equation, which omits both adiabatic deceleration and focusing, to re-derive the well-known telegrapher equation for particle transport. However, the derivation based on the propagating-source method yields an inhomogeneous form of the telegrapher equation; a form for which the well-known problem of coherent pulse solutions is absent. Furthermore, the inhomogeneous telegrapher equation is valid for times t much smaller than the ‘scattering time’ τ, i.e. for times t [Lt] τ, as well as for t > τ. More complicated forms of the BGK Boltzmann equation that now include focusing and adiabatic deceleration are solved. The basic results to emerge from this new approach to solving the BGK Boltzmann equation are the following. (i) Low-order polynomial expansions can be used to investigate particle propagation and transport at arbitrarily small times in a scattering medium. (ii) The theory of characteristics for linear hyperbolic equations illuminates the role of causality in the expanded integro-differential Fokker–Planck equation. (iii) The propagating-source approach is not restricted to isotropic initial data, but instead arbitrarily anisotropic initial data can be investigated. Examples using different ring-beam distributions are presented. (iv) Finally, the numerical scheme can include both small-angle and large-angle particle scattering operators (Part 2). A detailed discussion of the results for the various Boltzmann-equation models is given. In general, it is found that particle beams that experience scattering by, for example, interplanetary fluctuations are likely to remain highly anisotropic for many scattering times. This makes the use of the diffusion approximation for charged-particle transport particularly dangerous under many reasonable solar-wind conditions, especially in the inner heliosphere.

The data used in these analyses were compiled from individual feeding records of 1832 pigs from 70 sire families using FIRE (food intake recording equipment) system from Hunday Electronics Ltd at the Cotswold Pig Development Company. Pigs were on test between 45 (s.d. 2·76) kg and 95 (s.d. 6·78) kg. Daily food intake (DFI kg), food intake per visit (FlV kg), number of visits per day (NV), duration of each visit (TV min), time in the feeder per day (TD min), feeding rate (FR kg/min) and number of non-feeding visits per day (NFV), were measured as means of test and DFI was also recorded as means of bi-weekly periods of test. Performance test traits ofbackfat depth off test (BF mm), food conversion ratio (ECR kg/kg) and average daily gain (ADG kg), over the test period, were also measured.

Parameters were estimated by restricted maximum likelihood with a multivariate individual animal model. DFI had a heritability of 0·21 ranging from 0·18 to 0·26 over the four test periods. Correlations between DFI in each test period were high (rg = 0·75 to 0·99). DFI was highly correlated with performance test traits (0·61 to 0·78) but had low correlations with feeding pattern traits (0·0 to 0·24). The heritabilities of feeding pattern traits were low (0·06 to 0·11) with the exception of FIV (0·27) and NV (0·34) but correlations between feeding pattern traits were high. FIV, NV and TV were moderately correlated with ADG (rg = 0·49, -0·29, 0·33 respectively), BF (rg = 0·35, -0·15, 0·17 respectively) and ECR (rg = -0·12, 0·31, -0·27 respectively). Feeding patterns may be changed substantially by selection and the genetic correlations with performance test traits indicate that feeding patterns traits can be usefully incorporated in selection criteria to improve somewhat the accuracy of selection.

In this paper, positron annihilation measurements have been carried out on a-Si: H thin films deposited by plasma-enhanced chemical vapor deposition (PECVD) at high and low rates by means of the variable energy positron beam Doppler-broadening technique. The depth profiles of microvoids in the films grown under different conditions have been determined. We found a smaller void fraction in the surface region of all films compared to the bulk, and a smaller void fraction in low rate than in high growth rate films. By plotting S and W parameters in the (S, W) plane, we have shown that the vacancies in all of the high-rate and low-rate deposited intrinsic samples, and in differently doped low-rate samples are of the same nature, although there appears to be a higher density of defects in the boron than phosphorus doped films. The depth profiles of the microvoid-like defects in the a-Si: H films are extracted by use of the vepfit program.

We show how positron annihilation can distinguish vacancies in undoped hydrogenated amorphous silicon by performing Variable Energy Positron Annihilation Spectroscopy experiments before and after light soaking. We find that vacancy clusters, di-vacancies and a new type of single vacancies are created in undoped as-grown a-Si:H thin film by light illumination. The fact that the vacancy clusters are eliminated by the thermal annealing suggests that the Staebler-Wronski effect is closely related to vacancy clusters in a-Si:H material. The creation of vacancy clusters and redistribution of di-vacancies and even single vacancies probably result in photo-induced structural changes in this material.

By means of the slow positron beam Doppler-broadening technique, the depth profile of microvoids across a p-i-n double junction solar cell has been resolved. VEPFIT fitting results indicate an approximately uniform density of the defects throughout the solar cell, but with an enhanced concentration at all of the interfaces possibly due to network mismatch. In order to evaluate the internal electric field, Variable Energy Positron Annihilation Spectroscopy (VEPAS) measurements have been performed on a single junction pin solar cell at different biases. The internal electric field effect on positrons has also been examined in terms of the bias dependence of positron drift in a-Si:H single junction pin solar cell.

Recent experimental developments have cast doubt on the validity of the common assumption that the distribution of tail states of hydrogenated amorphous silicon exhibits a single exponential functional form. We employ transient photocurrent decay measurements to determine this distribution of tail states. In our approach, however, we determine the distribution of tail states directly from the experimental data, without assuming, a priori, a specific functional form. It is found that these experimental results are consistent with other more recent experimental determinations of the distribution of tail states, suggesting the possibility of deviations from a single exponential distribution of tail states in hydrogenated amorphous silicon.