137 research outputs found
Detection of flying-foxes using automated audio recorders
Flying-foxes are little understood in Australia largely due to their extreme mobility. This mobility is particularly evident in the two species (spectacled and little red) found across the north of Australia, where huge numbers of animals will suddenly converge on a region and then leave a few weeks later. To improve management of these species we need to understand the movement and ecology of the animals and this is not straightforward as the camps are often remote and inaccessible.
In this project we aimed to test the viability of using automated acoustic recorders for determining the presence of spectacled flying-foxes at camp locations. A Song Meter SM4 recorder was used to record flying-foxes in a number camps around South East QLD/Northern Rivers (black and grey-headed flying-foxes) and Cairns (spectacled flying-fox). A total of 35 hour of flying-foxes calls were recorded over a period of 8 weeks from August to October 2017.
The recordings were processed using a Binary Winnow classifier and Hidden Markov Model in Kaleidoscope Software (Wildlife Acoustics). Tagged one-minute recordings were used to train the Hidden Markov Model in Kaleidoscope which was subsequently used in classifying the remaining recordings.
Using this approach, we were able to quickly and easily detect the presence of flying-foxes in the acoustic recordings. In this way, ecologists can easily implement projects for long-term monitoring of flying-fox populations using remotely deployed acoustic recorders. It may also assist management agencies for urban planning in northern Australia. For future work, we will be investigate advanced machine learning algorithms coupled with flying-fox behavioural call patterns to attempt to distinguish the species of flying-fox from acoustic recordings
Deuteron Electroweak Disintegration
We study the deuteron electrodisintegration with inclusion of the neutral
currents focusing on the helicity asymmetry of the exclusive cross section in
coplanar geometry. We stress that a measurement of this asymmetry in the quasi
elastic region is of interest for an experimental determination of the weak
form factors of the nucleon, allowing one to obtain the parity violating
electron neutron asymmetry. Numerically, we consider the reaction at low
momentum transfer and discuss the sensitivity of the helicity asymmetry to the
strangeness radius and magnetic moment. The problems coming from the finite
angular acceptance of the spectrometers are also considered.Comment: 30 pages, Latex, 7 eps figures, submitted to Phys.Rev.C e-mail:
[email protected] , [email protected]
Relativistic nuclear structure effects in quasielastic neutrino scattering
Charged-current cross sections are calculated for quasielastic neutrino and
antineutrino scattering using a relativistic meson-nucleon model. We examine
how nuclear-structure effects, such as relativistic random-phase-approximation
(RPA) corrections and momentum-dependent nucleon self-energies, influence the
extraction of the axial form factor of the nucleon. RPA corrections are
important only at low-momentum transfers. In contrast, the momentum dependence
of the relativistic self-energies changes appreciably the value of the
axial-mass parameter, , extracted from dipole fits to the axial form
factor. Using Brookhaven's experimental neutrino spectrum we estimate the
sensitivity of M to various relativistic nuclear-structure effects.Comment: 26 pages, revtex, 6 postscript figures (available upon request
Parity violating target asymmetry in electron - proton scattering
We analyze the parity-violating (PV) components of the analyzing power in
elastic electron-proton scattering and discuss their sensitivity to the strange
quark contributions to the proton weak form factors. We point out that the
component of the analyzing power along the momentum transfer is independent of
the electric weak form factor and thus compares favorably with the PV beam
asymmetry for a determination of the strangeness magnetic moment. We also show
that the transverse component could be used for constraining the strangeness
radius. Finally, we argue that a measurement of both components could give
experimental information on the strangeness axial charge.Comment: 24 pages, Latex, 5 eps figures, submitted to Phys.Rev.
Discrimination, labour markets and the Labour Market Prospects of Older Workers: What Can a Legal Case Teach us?
As governments become increasingly concerned about the fiscal implications of the ageing population, labour market policies have sought to encourage mature workers to remain in the labour force. The âhuman capitalâ discourses motivating these policies rest on the assumption that older workers armed with motivation and vocational skills will be able to return to fulfilling work. This paper uses the post-redundancy recruitment experiences of former Ansett Airlines
flight attendants to develop a critique of these expectations. It suggests that policies to increase
older workersâ labour market participation will not succeed while persistent socially constructed age- and gender- typing shape labour demand. The conclusion argues for policies sensitive to the institutional structures that shape employer preferences, the competitive rationality of
discriminatory practices, and the irresolvable tension between workersâ human rights and employersâ property rights
Future Directions in Parity Violation: From Quarks to the Cosmos
I discuss the prospects for future studies of parity-violating (PV)
interactions at low energies and the insights they might provide about open
questions in the Standard Model as well as physics that lies beyond it. I cover
four types of parity-violating observables: PV electron scattering; PV hadronic
interactions; PV correlations in weak decays; and searches for the permanent
electric dipole moments of quantum systems.Comment: Talk given at PAVI 06 workshop on parity-violating interactions,
Milos, Greece (May, 2006); 10 page
The Strange Quark Contribution to the Proton's Magnetic Moment
We report a new determination of the strange quark contribution to the
proton's magnetic form factor at a four-momentum transfer Q2 = 0.1 (GeV/c)^2
from parity-violating e-p elastic scattering. The result uses a revised
analysis of data from the SAMPLE experiment which was carried out at the
MIT-Bates Laboratory. The data are combined with a calculation of the proton's
axial form factor GAe to determine the strange form factor GMs(Q2=0.1)=0.37 +-
0.20 +- 0.26 +- 0.07. The extrapolation of GMs to its Q2=0 limit and comparison
with calculations is also discussed.Comment: 6 pages, 1 figure, submitted to Phys. Lett.
Task specific influences of Parkinsonâs disease on the striato-thalamo-cortical and cerebello-thalamo-cortical motor circuitries
The motor deficits in Parkinsonâs disease (PD) have been primarily associated with internally guided (IG), but not externally guided (EG), tasks. This study investigated the functional mechanisms underlying this phenomenon using genetically-matched twins. Functional magnetic resonance images were obtained from a monozygotic twin pair discordant for clinical PD. Single-photon emission computed tomography neuroimaging using [123I](â)-2-ÎČ-carboxymethoxy-3-ÎČ-(4-iodophenyl)tropane confirmed their disease-discordant status by demonstrating a severe loss of transporter binding in the PD-twin, whereas the non-PD-twin was normal. Six runs of fMRI data were acquired from each twin performing EG and IG right-hand finger sequential tasks. The percentage of voxels activated in each of several regions of interest (ROI) was calculated. Multiple analysis of variance was used to compare each twinâs activity in ROIs constituting the striato-thalamo-cortical motor circuits [basal ganglia (BG)-cortical circuitry, but including the globus pallidus/putamen, thalamus, supplementary motor area, and primary motor cortex] and cerebello-thalamo-cortical circuits (referred to as the cerebellarâcortical circuitry, including the cerebellum, thalamus, somatosensory cortex, and lateral premotor cortex). During the EG task, there were no significant differences between the twins in bilateral BG-cortical pathways, either basally or after levodopa, whereas the PD-twin had relatively increased activity in the cerebellar-cortical pathways basally that was normalized by levodopa. During the IG task, the PD-twin had less activation than the non-PD-twin in ROIs of the bilateral BG-cortical and cerebellar-cortical pathways. Levodopa normalized the hypoactivation in the contralateral BG-cortical pathway, but âover-correctedâ the activation in the ipsilateral BG-cortical and bilateral cerebellar-cortical pathways. In this first fMRI study of twins discordant for PD, the data support the hypothesis that BG-cortical and cerebellar-cortical pathways are task-specifically influenced by PD. The levodopa-induced âover-activationâ of BG-cortical and cerebellar-cortical pathways, and its relevance to both compensatory changes in PD and the long-term effects of levodopa in PD, merit further exploration
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