85,329 research outputs found
Freshwater fish and crayfish communities of the tributaries of the Margaret River
Tributaries and headwaters of major rivers are known to be important spawning and nursery habitats of freshwater endemic fishes in south-western Australia (see for example the Collie River in Pen & Potter 1990, and the Blackwood River in Beatty et al. 2006, 2008). Fishes of the Margaret River have previously been examined by Morgan et al. (1998) and Morgan & Beatty (2003) with the monitoring of the functioning of the two fishways on the river documented in Morgan & Beatty (2004, 2007) and Beatty & Morgan (2008). The river is known to be of conservation importance due to it housing five of the eight endemic freshwater fishes of the south-west region, as well as housing the majority (five of the six species) of the Cherax species of freshwater crayfishes found in the south-west; including the Margaret River endemic Critically Endangered Hairy Marron.
Despite this known value and considerable volume of research on the fishes in the main channel of the Margaret River, little is known on the fishes and freshwater crayfishes of the river 19s major tributaries. The aim of this study is to document the freshwater fish distribution in the major tributaries of the Margaret River (i.e. Bramley, Darch, and Yalgardup Brooks) during or close to the breeding period for the majority of the species and to provide a broad assessment and comparison of population demographics of the different species in the different tributaries. This information is required for the formulation of River Action Plans for these systems by the Cape to Cape Catchments Group
Competition between charge and spin order in the extended Hubbard model on the triangular lattice
Several new classes of compounds can be modeled in first approximation by
electrons on the triangular lattice that interact through on-site repulsion
as well as nearest-neighbor repulsion . This extended Hubbard model on a
triangular lattice has been studied mostly in the strong coupling limit for
only a few types of instabilities. Using the extended two-particle self
consistent approach (ETPSC), that is valid at weak to intermediate coupling, we
present an unbiased study of the density and interaction dependent crossover
diagram for spin and charge density wave instabilities of the normal state at
arbitrary wave vector. When dominates over and electron filling is
large, instabilities are chiefly in the spin sector and are controlled mostly
by Fermi surface properties. Increasing eventually leads to charge
instabilities. In the latter case, it is mostly the wave vector dependence of
the vertex that determines the wave vector of the instability rather than Fermi
surface properties. At small filling, non-trivial instabilities appear only
beyond the weak coupling limit. There again, charge density wave instabilities
are favored over a wide range of dopings by large at wave vectors
corresponding to superlattice in real space.
Commensurate fillings do not play a special role for this instability.
Increasing leads to competition with ferromagnetism. At negative values of
or , neglecting superconducting fluctuations, one finds that charge
instabilities are favored. In general, the crossover diagram presents a rich
variety of instabilities. We also show that thermal charge-density wave
fluctuations in the renormalized classical regime can open a pseudogap in the
single-particle spectral weight, just as spin or superconducting fluctuations
Weakly nonlinear waves in magnetized plasma with a slightly non-Maxwellian electron distribution. Part 2, Stability of cnoidal waves
We determine the growth rate of linear instabilities resulting from long-wavelength transverse perturbations applied to periodic nonlinear wave solutions to the Schamel–Korteweg–de Vries–Zakharov–Kuznetsov (SKdVZK) equation which governs weakly nonlinear waves in a strongly magnetized cold-ion plasma whose electron distribution is given by two Maxwellians at slightly different temperatures. To obtain the growth rate it is necessary to evaluate non-trivial integrals whose number is kept to a minimum by using recursion relations. It is shown that a key instance of one such relation cannot be used for classes of solution whose minimum value is zero, and an additional integral must be evaluated explicitly instead. The SKdVZK equation contains two nonlinear terms whose ratio b increases as the electron distribution becomes increasingly flat-topped. As b and hence the deviation from electron isothermality increases, it is found that for cnoidal wave solutions that travel faster than long-wavelength linear waves, there is a more pronounced variation of the growth rate with the angle θ at which the perturbation is applied. Solutions whose minimum values are zero and which travel slower than long-wavelength linear waves are found, at first order, to be stable to perpendicular perturbations and have a relatively narrow range of θ for which the first-order growth rate is not zero
Method and apparatus for aligning a laser beam projector Patent
Laser beam projector for continuous, precise alignment between target, laser generator, and astronomical telescope during trackin
Method of directing a laser beam with very high accuracy
System will collimate and direct an argon laser beam with high angular tracking accuracy at objects on the moons surface. It can be adapted to missile and satellite tracking
Dynamics of uniaxial hard ellipsoids
We study the dynamics of monodisperse hard ellipsoids via a new event-driven
molecular dynamics algorithm as a function of volume fraction and aspect
ratio . We evaluate the translational and the rotational
diffusion coefficient and the associated isodiffusivity lines in the
plane. We observe a decoupling of the translational and rotational
dynamics which generates an almost perpendicular crossing of the
and isodiffusivity lines. While the self intermediate scattering
function exhibits stretched relaxation, i.e. glassy dynamics, only for large
and , the second order orientational correlator
shows stretching only for large and small values. We discuss these
findings in the context of a possible pre-nematic order driven glass
transition.Comment: accepted by Phys. Rev. Let
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A brief history of the British Neuroscience Association
As the British Neuroscience Association commemorates 50 years of existence in 2018, this article recalls its founding as a discussion group, its establishment as the Brain Research Association, its transition to a professional society encompassing all aspects of neuroscience research, both clinical and non-clinical, and its re-branding as the British Neuroscience Association in the late 1990s. Neuroscience as a branch of life science has expanded hugely in the last 25 years and the British Neuroscience Association has adapted, frequently working with partner societies, to serve as an interdisciplinary hub for professionals working in this exciting and crucial field. The authors have attempted to highlight some key events in the Association’s history and acknowledge the contributions made by many people over half a century
Observations of the solar particle event of 5 to 12 February 1965 with Mariner IV AND Injun IV
Solar energetic particle intensities obtained with Mariner IV and Injun IV during 5-12 February 1965 cosmic ray even
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