63 research outputs found
Estimating Pasture Land Cover in the New England Region of Northern New South Wales
Land cover across the southern Australian temperate agricultural region comprises primarily of native pasture, introduced improved pastures and crops for livestock production and also perennial remnant vegetation. A feed-base pasture audit was carried out throughout southern Australia commencing mid-year 2011 (Donald and Burge 2012; Donald et al. 2012). The purpose of the audit was to map and analyse information obtained about the pasture feed-base for livestock production by surveying Statistical Local Areas (SLAs) across the southern states. The purpose of this Feed-Base audit was to survey pastures within agricultural NSW, Victoria, Tasmania, South Australia and South-Western Australia, collate these data into an organised database, and prepare a short report and summarise by tabulating and mapping pasture species abundance and distribution. Data collected were based on “desk-top estimates” by state district agronomists and agricultural consultants. In this paper a method using satellite imagery is described on how more objective assessments of pasture types can be provided as a means to discriminate between the SLA’s major pasture classes far more objectively than by visual assessment. Satellite remote sensing may be used to define landcover classes for large regional areas. A number of procedures have been developed to discriminate between pastures, crop and woody vegetation (for example Hill et al. 1997, Emelyanova et al. 2008). In the Hill study (Hill et al. 1997) NOAA AVHRR NDVI provided spatial land cover maps of pasture cover at 1 km resolution. The classifications results in that study showed that satellite information may be used to help in the interpretation of pasture survey results, and in turn, the survey data can provide some validation data for the pasture types ascribed to the remotely sensed classes.
In this study daily temporal continental scale imagery from 250 m2 resolution TERRA and AQUA satellite Moderate Resolution Imaging Spectroradiometer (MODIS) normalised difference vegetation index (NDVI) composited into weekly continental images provided a means to assess temporal profile of spectral greenness over the growing season
Local Ferroelectricity in SrTiO_3 Thin Films
The temperature-dependent polarization of SrTiO_3 thin films is investigated
using confocal scanning optical microscopy. A homogeneous out-of-plane and
inhomogeneous in-plane ferroelectric phase are identified from images of the
linear electrooptic response. Both hysteretic and non-hysteretic behavior are
observed under a dc bias field. Unlike classical transitions in bulk
ferroelectrics, local ferroelectricity is observed at temperatures far above
the dielectric permittivity maximum. The results demonstrate the utility of
local probe experiments in understanding inhomogeneous ferroelectrics.Comment: 8 pages, 3 figures, accepted for publication in PR
Improving the Feeding Value of Dryland Lucerne in Australia
Lucerne (Medicago sativa L.) is the most widely grown perennial legume species in southern Australia. Within Australian farming systems it plays an important role in the provision of high-quality feed for livestock, nitrogen fixation and dewatering soils to reduce watertable recharge and dryland salinity (Cocks 2001). The majority of lucerne varieties have been developed for the areas with high rainfall or supplementary irrigation. The new challenge is to develop lucerne cultivars specifically for dryland mixed farming systems in temperate and mediterranean climate zones (Humphries and Auricht, 2001). Persistence in these environments and feeding value to sheep are critical selection traits. In this paper we compare nutritive traits of 35 commercial and experimental accessions of lucerne, sampled during the vegetative phase, and test the hypothesis that there will be significant differences between the accessions for in vitro dry matter digestibility (DMD), crude protein (CP), acid detergent fibre (ADF), neutral detergent fibre (NDF) and hemicellulose
Superconductivity in diamond
We report the discovery of superconductivity in boron-doped diamond
synthesized at high pressure (8-9 GPa) and temperature (2,500-2,800 K).
Electrical resistivity, magnetic susceptibility, specific heat, and
field-dependent resistance measurements show that boron-doped diamond is a
bulk, type-II superconductor below the superconducting transition temperature
Tc=4 K; superconductivity survives in a magnetic field up to Hc2(0)=3.5 T. The
discovery of superconductivity in diamond-structured carbon suggests that Si
and Ge, which also form in the diamond structure, may similarly exhibit
superconductivity under the appropriate conditions.Comment: 13 pages, 4 figure
The Flux-Line Lattice in Superconductors
Magnetic flux can penetrate a type-II superconductor in form of Abrikosov
vortices. These tend to arrange in a triangular flux-line lattice (FLL) which
is more or less perturbed by material inhomogeneities that pin the flux lines,
and in high- supercon- ductors (HTSC's) also by thermal fluctuations. Many
properties of the FLL are well described by the phenomenological
Ginzburg-Landau theory or by the electromagnetic London theory, which treats
the vortex core as a singularity. In Nb alloys and HTSC's the FLL is very soft
mainly because of the large magnetic penetration depth: The shear modulus of
the FLL is thus small and the tilt modulus is dispersive and becomes very small
for short distortion wavelength. This softness of the FLL is enhanced further
by the pronounced anisotropy and layered structure of HTSC's, which strongly
increases the penetration depth for currents along the c-axis of these uniaxial
crystals and may even cause a decoupling of two-dimensional vortex lattices in
the Cu-O layers. Thermal fluctuations and softening may melt the FLL and cause
thermally activated depinning of the flux lines or of the 2D pancake vortices
in the layers. Various phase transitions are predicted for the FLL in layered
HTSC's. The linear and nonlinear magnetic response of HTSC's gives rise to
interesting effects which strongly depend on the geometry of the experiment.Comment: Review paper for Rep.Prog.Phys., 124 narrow pages. The 30 figures do
not exist as postscript file
Organic Superconductors: when correlations and magnetism walk in
This survey provides a brief account for the start of organic
superconductivity motivated by the quest for high Tc superconductors and its
development since the eighties'. Besides superconductivity found in 1D organics
in 1980, progresses in this field of research have contributed to better
understand the physics of low dimensional conductors highlighted by the wealth
of new remarkable properties. Correlations conspire to govern the low
temperature properties of the metallic phase. The contribution of
antiferromagnetic fluctuations to the interchain Cooper pairing proposed by the
theory is borne out by experimental investigations and supports
supercondutivity emerging from a non Fermi liquid background. Quasi one
dimensional organic superconductors can therefore be considered as simple
prototype systems for the more complex high Tc materials.Comment: 41 pages, 21 figures to be published in Journal of Superconductivity
and Novel Magnetis
Integrating MODIS satellite imagery and proximal vegetation sensors to enable precision livestock management
In temperate and mediterranean regions of Australia, utilisation of pastures by grazing animals can often be as low as thirty percent. Feed budgeting is a critical strategy for improving feed utilisation and there are now pasture evaluation and monitoring programs available to farmers across Australia to enable them to estimate Pasture Growth Rate (PGR) and feed availability or Feed On Offer (FOO). Unfortunately, many farmers do not have the confidence or the time available to make regular accurate field estimates across large and remote paddocks. It is also extremely difficult to measure the spatial variation of FOO and PGR. Both satellite image-based systems, such as that derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and on-ground, active sensors and spectroradiometers have limitations. The MODIS sensor, although offering a daily acquisition interval, has a spatial resolution of 6.25ha which does create an issue in describing higher resolution spatial variation in fields and is susceptible to the unwanted artefacts associated with non-forageable vegetation such as trees. On-ground (proximal) sensors such as the Crop Circle™ instrument, can be integrated with with global positioning systems (GPS) and dataloggers and operated on-the-go, but field-coverage require a vast number of samples that in turn require tedious analysis and particularly if done at frequent intervals. The aim of this paper is to test whether the MODIS and Crop Circle™ data can be intergrated to provide the benefit of both high spatial and temporal resolution. Such information would be useful when determining feed on offer and pasture growth rate information at weekly or strategic times from MODIS acquisitions including other biophysical and physical relevant attributes. This electronic document is a live template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document. © 2012 IEEE.Associated Grant:Spatial Informatics CR
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