Notes: Abstract This paper provides a comprehensive analysis of the dynamics of the flow of minor ion species in the solar wind under the combined influences of gravity, Coulomb friction (with protons), rotational forces (arising from the Sun's rotation and the interplanetary spiral magnetic field) and wave forces (induced in the minor ion flow by Alfvén waves propagating in the solar wind). It is assumed that the solar wind can be considered as a proton-electron plasma which is, to a first approximation, unaffected by the presence of minor ions. In the dense hot region near the Sun Coulomb friction accelerates minor ions outwards against the gravitational force, part of which is cancelled by the charge-separation electric field. Once the initial acceleration has been achieved, wave and rotational forces assist Coulomb friction in further increasing the minor ion speed so that it becomes comparable with, or perhaps even exceeds, the solar wind speed. A characteristic feature of the non-resonant wave force is that it tends to bring the minor ion flow into an equilibrium where the radial speed matches the Alfvén speed relative to the solar wind speed, whereas Coulomb friction and rotational forces tend to bring the flow into an equilibrium where the radial speed of the minor ions equals the solar wind speed. Therefore, provided that there is sufficient wave energy and Coulomb friction is weak, the minor ion speed can be ‘trapped’ between these two speeds. This inteststing result is in qualitative agreement with observational findings to the effect that the differential flow speed between helium ions and protons is controlled by the ratio of the solar wind expansion time to the ion-proton collision time. If the thermal speeds of the protons and minor ions are small compared to the Alfvén speed, two stable equilibrium speeds can exist because the rapid decrease in the Coulomb cross-section with increasing differential flow speed allows the non-resonant wave force to balance Coulomb friction at more than one ion speed. However, it must be emphasized that resonant wave acceleration and/or strong ion partial pressure gradients are required to achieve radial speeds of minor ions in excess of the proton speed, since, as is shown in Section 4, the non-resonant wave acceleration on protons and minor ions are identical when their radial speeds are the same, with the result that, in the solar wind, non-resonant wave acceleration tends (asymptotically) to equalize minor ion and proton speeds.

Notes: Abstract The properties of ‘discontinuous’ transitions in a current-carrying plasma are analyzed by formulating the problem in terms of the two-fluid (i.e., electrons and ions) equations. The jump conditions, which connect states on either side of a discontinuity, are derived and it is shown that these are similar to the ordinary gas-dynamic Rankine-Hugoniot conditions except that there are extra terms which represent an enhanced mass flux in the momentum equation, and an additional heat, flux in the energy equation, both of which arise from the existence of a current flow through the discontinuity. the additional heat flux, which is due to collisions between electrons and ions and is carried by the electrons, plays a role analogous to the heat of reaction in the theory of combustion waves and gives rise to Hugoniots (i.e., curves in the pressure-specific volume plane representing the locus of states satisfying conservation of total plasma energy) which may be either ‘exothermic’ or ‘endothermic’ in character. Thus the classification of the various types of discontinuities, permitted by the jump relations, adopted here follows the classical description of detonation and deflagration waves and is based on the nature of the flow (i.e., whether the flow is ‘subsonic’ or ‘supersonic’) ahead of and behind the discontinuity. In an artificial way we show that the effects of reflected particles on such discontinuities can be to alter the nature of the discontinuity. For example in the special case of adiabatic transitions only ‘weak’ transitions are permitted in the absence of reflected particles, whereas in their presence all types (weak and strong) are possible. The end states permitted by the jump conditions must be joined together by a valid internal structure which can be obtained only by solving the full equations of motion. These are set up and we ask what extra conditions must be fulfilled by a transition characterized by a monotonic change in potential going from zero at one end to a constant value at the other, assuming that the plasma is charge neutral outside the transition region. In the case of adiabatic transitions one extra condition is imposed and this turns out to be a generalization of Block's (1972) self-consistency condition for double layers (which in its turn is an extension of Bohm's condition for the existence of wall sheaths). However the inclusion of dissipative effects indicates that adiabatic transitions are degenerate since the inclusion of dissipation shows that no extra conditions are imposed by requirements stemming from considerations of the self-consistency of the internal structure. As an example of how such discontinuities may be fitted into flow problems, we examine the construction of discontinuous periodic solutions for streaming ions and electrons. allowing for collisions with a background neutral gas. The idea here is borrowed from the phenomenon of ‘roll waves’, which occur in water flow along an inclined channel including frictional effects, and consist of a series of hydraulic jumps (or ‘bores’) separated by stretches of smooth flow.

Notes: Abstract This paper extends some previous work on the acceleration of minor ions in the solar wind to include the effects of wave acceleration and heating arising from minor ions interacting via the gyroresonance with ion cyclotron waves. Resonant wave acceleration is made up of two contributions, the first, and generally the more important, is a ‘local’ acceleration which is proportional to the wave power and the number of resonant particles and is also sensitive to the details of the distribution function; while the other contribution is basically ‘fluid dynamic’ in character, arises from the inhomogeneity of the medium and is proportional to the radial gradient of the resonant wave power. Under suitable cir-cumstances both contributions exhibit the feature that heavier ions receive greater acceleration than lighter ones. Also the kinematics of the resonance shows that the resonance wave acceleration switches off above a maximum differential speed, between ions and protons, which increases with increasing ratio of mass to charge. We also examine briefly possible beam instabilities driven by the streaming of minor ions relative to protons.

Notes: Summary Egg implant studies on sheep demonstrate that the relative fitness of resistance genotypes of the sheep blowfly,Lucilia cuprina, changes over time for the 2 insecticides dieldrin and diazinon. The results suggest that selection may occur following exposure of larvae to sub-lethal concentrations and help to explain the relative rates of the development of resistance to dieldrin and diazinon byL. cuprina.

Notes: Summary Twenty seven knees, mainly of rheumatoid patients, received intra-articular 90Y for chronic effusions; 24% were effusion-free at 6 months. In vitro chemical, radiation (32P-induced), and combined effects of cold (non-radioactive) yttrium and 32P on synovial fluid mononuclear cells, failed to show any significant correlation with subjective and/or objective clinical effects at 3 or 6 months. If 90Y exerts its therapeutic effect via these cells, it probably does so other than by a direct effect on mononuclear cell viability.

Notes: Summary Data were collected over four vintage seasons at the “Chateau Tahbilk” winery. The distribution of adults, larvae and pupae of D. melanogaster and D. simulans was recorded over a pile of grape residues during two different stages of its decomposition. Active fermentation characterized the first of these stages, but was much less apparent in the later stage. The distribution of adults was similar for both stages. However, while larvae and pupae of both species were observed in the post fermentation residues essentially only D. melanogaster larvae and pupae were present during the fermentation stage. During this stage larvae were aggregated beneath the surface to a depth of 10 cm. Here the average temperature was about 29°C and ethanol and acetic acid concentrations were around 7% (v/v) and 3% (v/v), respectively. Laboratory results allow a description of the physiological and behavioural responses of both species to ethanol or acetic acid concentration and to temperature differences. These results appear sufficient to explain the distribution of the species between and within the residue stages. However, before general statements of resource utilization or species interaction can be made, the need to study different stages of the life cycle is highlighted.

Notes: Summary Thalamo-caudate projection neurones were identified in cats by antidromic activation from the caudate nucleus, under chloralose anaesthesia or in cerveau isolé preparations. Units in nuclei centralis lateralis, medialis dorsalis, and centrum medianum-parafascicularis responded antidromically to one or more electrodes of a caudate nucleus array at latencies ranging from 0.4 to 16 ms. The responses did not appear to result from stimulus spread to the internal capsule. A separate population of medial thalamic units responded post-synaptically to caudate stimulation, at modal latency exceeding modal antidromic latency by 2 ms. Comparison of apparent conduction velocities for each thalamic nucleus indicated that the postsynaptic responses were activated by collaterals of thalamo-caudate neurones. A proportion of thalamo-caudate neurones responded to somatic stimulation; some of these were inhibited by caudate stimulation, and a few discharged on substantia nigra stimulation. These results demonstrate the possibility of somatic afferent and nigrofugal inputs to the caudate nucleus mediated by neurones of the medial thalamus.

Notes: Abstract Coastal dunes in Queensland are usually vegetated because climatic conditions favour the growth of dune plants. Occasionally extreme climatic conditions, e.g. gales, droughts, wave erosion, or man's activities, e.g. grazing, access, development, destroy dunal vegetation and onshore winds move sand inland, accelerating coastal erosion. Replacement of vegetation is indicated in severe cases. The paper described trials done on Stradbroke Island into methods of re-establishing vegetation on dunes using different surface mulch treatments, including organic materials (straw and brush), and spray-on emulsions (bitumen, P.V.A. mineral oil-synthetic latex). All treatments (except the oil-latex emulsion) allowed ready establishment of vegetation. The bitumen and P.V.A. treatments could be used to replace the traditional organic mulches, subject to certain conditions. Data is presented on climate, soil temperatures, resistance to wind erosion plant ground covers and densities.

Notes: Abstract It is shown that the discontinuous jump in the vertical wave energy flux of slow hydromagnetic-gravity waves, occurring at a critical level, which is accompanied by wave absorption, and the existence of a reflection point imply that slow waves are trapped in the solar atmosphere. Thus such a system behaves as a leaky wave guide.