1,143 research outputs found
A simplified mulesing crush
DURING the last two years Mr. Tom Flanigan, a mulesing contractor in a large area centred at Katanning, has performed the mules-tailstrip operation on many thousands of lambs and sheep
Sheep can be more profitable in the wheatbelt
TRADITIONALLY, wheatbelt farmers have looked upon sheep as being subsidiary, or at best, complementary to their main activity, wheat growing.
Because there has been a mistaken belief that clover would not grow, these farmers have depended upon native grasses and crop remains (stubble) for sheep feed, a practice which has put a limit to the number of sheep a property could support
How to identify twin-born lambs
IN the past few years it has become widely accepted that the ability to produce twin or multiple lambs is a heritable characteristic.
This means that breeding from sheep born as twins should give more multiple births and higher lambing percentages than breeding from sheep born as single lambs
Universal correlators and distributions as experimental signatures of 2+1 Kardar-Parisi-Zhang growth
We examine height-height correlations in the transient growth regime of the
2+1 Kardar-Parisi-Zhang (KPZ) universality class, with a particular focus on
the {\it spatial covariance} of the underlying two-point statistics,
higher-dimensional analog of the 1+1 KPZ Class Airy process. Making
comparison to AFM kinetic roughening data in 2d organic thin films, we use our
universal 2+1 KPZ spatial covariance to extract key scaling parameters for this
experimental system. Additionally, we explore the i) height, ii) local
roughness, and iii) extreme value distributions characteristic of these
oligomer films, finding compelling agreement in all instances with our
numerical integration of the KPZ equation itself. Finally, investigating
nonequilibrium relaxation phenomena exhibited by 2+1 KPZ Class models, we have
unearthed a universal KPZ ageing kinetics. In experiments with ample data in
the time domain, our 2+1 KPZ Euler {\it temporal covariance} will allow a
quick, independent estimate of the central KPZ scaling parameter.Comment: 6 Pages, 5 Figure
Singularities of the renormalization group flow for random elastic manifolds
We consider the singularities of the zero temperature renormalization group
flow for random elastic manifolds. When starting from small scales, this flow
goes through two particular points and , where the average value
of the random squared potential turnes negative ($l^{*}$) and where
the fourth derivative of the potential correlator becomes infinite at the
origin ($l_{c}$). The latter point sets the scale where simple perturbation
theory breaks down as a consequence of the competition between many metastable
states. We show that under physically well defined circumstances $l_{c} to negative values does not
take place.Comment: RevTeX, 3 page
Ground State Wave Function of the Schr\"odinger Equation in a Time-Periodic Potential
Using a generalized transfer matrix method we exactly solve the Schr\"odinger
equation in a time periodic potential, with discretized Euclidean space-time.
The ground state wave function propagates in space and time with an oscillating
soliton-like wave packet and the wave front is wedge shaped. In a statistical
mechanics framework our solution represents the partition sum of a directed
polymer subjected to a potential layer with alternating (attractive and
repulsive) pinning centers.Comment: 11 Pages in LaTeX. A set of 2 PostScript figures available upon
request at [email protected] . Physical Review Letter
Quantized Scaling of Growing Surfaces
The Kardar-Parisi-Zhang universality class of stochastic surface growth is
studied by exact field-theoretic methods. From previous numerical results, a
few qualitative assumptions are inferred. In particular, height correlations
should satisfy an operator product expansion and, unlike the correlations in a
turbulent fluid, exhibit no multiscaling. These properties impose a
quantization condition on the roughness exponent and the dynamic
exponent . Hence the exact values for two-dimensional
and for three-dimensional surfaces are derived.Comment: 4 pages, revtex, no figure
Correlation Functions for an Elastic String in a Random Potential: Instanton Approach
We develop an instanton technique for calculations of correlation functions
characterizing statistical behavior of the elastic string in disordered media
and apply the proposed approach to correlations of string free energies
corresponding to different low-lying metastable positions. We find high-energy
tails of correlation functions for the case of long-range disorder (the
disorder correlation length well exceeds the characteristic distance between
the sequential string positions) and short-range disorder with the correlation
length much smaller then the characteristic string displacements. The former
case refers to energy distributions and correlations on the distances below the
Larkin correlation length, while the latter describes correlations on the large
spatial scales relevant for the creep dynamics.Comment: 5 pages; 1 .eps figure include
Upper critical dimension, dynamic exponent and scaling functions in the mode-coupling theory for the Kardar-Parisi-Zhang equation
We study the mode-coupling approximation for the KPZ equation in the strong
coupling regime. By constructing an ansatz consistent with the asymptotic forms
of the correlation and response functions we determine the upper critical
dimension d_c=4, and the expansion z=2-(d-4)/4+O((4-d)^2) around d_c. We find
the exact z=3/2 value in d=1, and estimate the values 1.62, 1.78 for z, in
d=2,3. The result d_c=4 and the expansion around d_c are very robust and can be
derived just from a mild assumption on the relative scale on which the response
and correlation functions vary as z approaches 2.Comment: RevTex, 4 page
Low frequency response of a collectively pinned vortex manifold
A low frequency dynamic response of a vortex manifold in type-II
superconductor can be associated with thermally activated tunneling of large
portions of the manifold between pairs of metastable states (two-level
systems). We suggest that statistical properties of these states can be
verified by using the same approach for the analysis of thermal fluctuations
the behaviour of which is well known. We find the form of the response for the
general case of vortex manifold with non-dispersive elastic moduli and for the
case of thin superconducting film for which the compressibility modulus is
always non-local.Comment: 8 pages, no figures, ReVTeX, the final version. Text strongly
modified, all the results unchange
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