Julian M. Hughes

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Recent studies of the genetic structure of stream-dwelling organisms have suggested that fine-scale patterns are the consequence of patchy recruitment from a small number of matings and limited in-stream dispersal. Predictions of this hypothesis were tested by spatial and temporal analysis of the genetic structure of populations of a stream mayfly (Bungona(More)
Territorial group size in Australian magpies (Gymnorhina tibicen) ranges from monogamous pairs to groups of more than 20 individuals. It has been hypothesized that large territorial groups result from the retention of juveniles after a breeding effort. If this is true, local populations consisting of large groups are likely to exhibit the most genetic(More)
Hildebrand and Hansen solubility parameters are commonly used to identify suitable solvents for the dispersion or dissolution of a range of solutes, from small molecules to graphene. This practice is based on a number of equations which predict the enthalpy of mixing to be minimized when the solubility parameters of solvent and solute match. However, such(More)
Physoclist fish are able to regulate their buoyancy by secreting gas into their hydrostatic organ, the swim bladder, as they descend through the water column and by resorbing gas from their swim bladder as they ascend. Physoclists are restricted in their vertical movements due to increases in swim bladder gas volume that occur as a result of a reduction in(More)
Understanding the movement dynamics of marine fish provides valuable information that can assist with species management, particularly regarding protection within marine protected areas (MPAs). We performed an acoustic tagging study implemented within the Port Stephens-Great Lakes Marine Park on the mid-north coast of New South Wales, Australia, to assess(More)
[1] A study of the cross–polar cap potential estimated by the HF Super Dual Auroral Radar Network (SuperDARN) during periods of steady interplanetary magnetic field (IMF) and solar wind velocity is presented. The potential estimates were examined as time series along with time series of the IMF and solar wind. In addition, the data were examined(More)
Differences in genetic structure of samples of monarch butterflies caught at different times of day have been reported previously. This paper compares differences in allele and heterozygote frequencies at the Pgi locus between animals flying early and those flying late in outdoor flight cages and between animals able and animals unable to fly at a constant(More)
Knowledge of the influence of both spatial and temporal environmental gradients on life history traits and population demographics is a critical requirement in the management of exploited fish populations. This study examined variation in the demographics of Arripis trutta, an economically-important pelagic fish species with a broad latitudinal distribution(More)
Patterns in the timing of spawning of the eastern Australian river garfish Hyporhamphus regularis ardelio were investigated by sampling fish throughout 24 h during their peak spawning period. Patterns in gonadosomatic indices, the presence of hydrated oocytes and post-ovulatory follicles in histological ovary sections, together with previously demonstrated(More)
Interpretation of changes in midpoint potential of the "special pair" in bacterial photosynthetic reaction centers caused by site-directed mutagenesis is discussed in terms of a simple tight-binding model which relates them to concomitant variations in spin distribution between the two bacteriochlorophyll molecules of the special pair. Our analysis improves(More)
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