1,139 research outputs found
Foster carers in New South Wales: profile and projections based on ABS Census data
Administrative data on foster carers in New South Wales (NSW) are sadly lacking. Based on research commissioned by the NSW Department of Community Services, this paper uses the Australian Bureau of Statistics Census of Population and Housing and other data to provide up to date information on the characteristics of foster carers and the demographic trends that are influencing their numbers. Census data indicate that foster carer families are most likely to contain women aged 35-54 years, not in the labour force. Couples account for two thirds of all foster carers, with the majority of those couples also caring for birth children. While single parents account for less than one-fifth of all foster carers, they are more likely to foster than couples, either with or without birth children. Higher rates of fostering were found in relatively disadvantaged areas. Projected increases in female labour force participation are expected to contribute to a decline (or to slower growth) in the number of foster carers over the next decade. However, projected increases in sole parent families and couples without children are expected to have the opposite effect. The relative magnitude of these effects was not ascertained
Mechano-Biological Interactions of Endothelial Cells
Atherosclerosis is an ever-increasing cause of morbidity in the western world. Current surgical treatments include bypass grafts and coronary artery stents. However, there is still a need for alternative approaches especially for those who cannot receive conventional therapy. Tissue engineering is one such approach that may hold the key to the repair and regeneration. Tissue engineering is one such approach that may hold the key to the repair and regeneration of coronary arteries. Nevertheless, many questions need to be answered before a vialbe vascular tissie with the inherent properties of native tissue becomes a real contender with the surgical therapies in use today
Electrothermal equivalent three-dimensional Finite Element Model of a single neuron
Objective: We propose a novel approach for modelling the inter-dependence of
electrical and mechanical phenomena in nervous cells, by using electro-thermal
equivalences in finite element (FE) analysis so that existing thermo-mechanical
tools can be applied. Methods: First, the equivalence between electrical and
thermal properties of the nerve materials is established, and results of a pure
heat conduction analysis performed in Abaqus CAE Software 6.13-3 are validated
with analytical solutions for a range of steady and transient conditions. This
validation includes the definition of equivalent active membrane properties
that enable prediction of the action potential. Then, as a step towards fully
coupled models, electromechanical coupling is implemented through the
definition of equivalent piezoelectric properties of the nerve membrane using
the thermal expansion coefficient, enabling prediction of the mechanical
response of the nerve to the action potential. Results: Results of the coupled
electro-mechanical model are validated with previously published experimental
results of deformation for the squid giant axon, crab nerve fibre and garfish
olfactory nerve fibre. Conclusion: A simplified coupled electro-mechanical
modelling approach is established through an electro-thermal equivalent FE
model of a nervous cell for biomedical applications. Significance: One of the
key findings is the mechanical characterization of the neural activity in a
coupled electro-mechanical domain, which provides insights into the
electromechanical behaviour of nervous cells, such as thinning of the membrane.
This is a first step towards modelling 3D electromechanical alteration induced
by trauma at nerve bundle, tissue and organ levels
Head-to-nerve analysis of electromechanical impairments of diffuse axonal injury
The aim was to investigate mechanical and functional failure of diffuse
axonal injury (DAI) in nerve bundles following frontal head impacts, by finite
element simulations. Anatomical changes following traumatic brain injury are
simulated at the macroscale by using a 3D head model. Frontal head impacts at
speeds of 2.5-7.5 m/s induce mild-to-moderate DAI in the white matter of the
brain. Investigation of the changes in induced electromechanical responses at
the cellular level is carried out in two scaled nerve bundle models, one with
myelinated nerve fibres, the other with unmyelinated nerve fibres. DAI
occurrence is simulated by using a real-time fully coupled electromechanical
framework, which combines a modulated threshold for spiking activation and
independent alteration of the electrical properties for each three-layer fibre
in the nerve bundle models. The magnitudes of simulated strains in the white
matter of the brain model are used to determine the displacement boundary
conditions in elongation simulations using the 3D nerve bundle models. At high
impact speed, mechanical failure occurs at lower strain values in large
unmyelinated bundles than in myelinated bundles or small unmyelinated bundles;
signal propagation continues in large myelinated bundles during and after
loading, although there is a large shift in baseline voltage during loading; a
linear relationship is observed between the generated plastic strain in the
nerve bundle models and the impact speed and nominal strains of the head model.
The myelin layer protects the fibre from mechanical damage, preserving its
functionalities
Parameterizing animal sounds and motion with animal-attached tags to study acoustic communication
Funding: Dolphin Quest, Inc.; School of Biology, University of St Andrews; Scottish Universities Life Sciences Alliance; Office of Naval Research; Marine Alliance for Science and Technology for Scotland; Horizon H2020.Stemming from the traditional use of field observers to score states and events, the study of animal behaviour often relies on analyses of discrete behavioural categories. Many studies of acoustic communication record sequences of animal sounds, classify vocalizations, and then examine how call categories are used relative to behavioural states and events. However, acoustic parameters can also convey information independent of call type, offering complementary study approaches to call classifications. Animal-attached tags can continuously sample high-resolution behavioural data on sounds and movements, which enables testing how acoustic parameters of signals relate to parameters of animal motion. Here, we present this approach through case studies on wild common bottlenose dolphins (Tursiops truncatus). Using data from sound-and-movement recording tags deployed in Sarasota (FL), we parameterized dolphin vocalizations and motion to investigate how senders and receivers modified movement parameters (including vectorial dynamic body acceleration, âVeDBAâ, a proxy for activity intensity) as a function of signal parameters. We show that (1) VeDBA of one female during consortships had a negative relationship with centroid frequency of male calls, matching predictions about agonistic interactions based on motivation-structural rules; (2) VeDBA of four males had a positive relationship with modulation rate of their pulsed vocalizations, confirming predictions that click-repetition rate of these calls increases with agonism intensity. Tags offer opportunities to study animal behaviour through analyses of continuously sampled quantitative parameters, which can complement traditional methods and facilitate research replication. Our case studies illustrate the value of this approach to investigate communicative roles of acoustic parameter changes.Publisher PDFPeer reviewe
Optimal combination of signals from co-located gravitational wave interferometers for use in searches for a stochastic background
This article derives an optimal (i.e., unbiased, minimum variance) estimator
for the pseudo-detector strain for a pair of co-located gravitational wave
interferometers (such as the pair of LIGO interferometers at its Hanford
Observatory), allowing for possible instrumental correlations between the two
detectors. The technique is robust and does not involve any assumptions or
approximations regarding the relative strength of gravitational wave signals in
the detector pair with respect to other sources of correlated instrumental or
environmental noise. An expression is given for the effective power spectral
density of the combined noise in the pseudo-detector. This can then be
introduced into the standard optimal Wiener filter used to cross-correlate
detector data streams in order to obtain an optimal estimate of the stochastic
gravitational wave background. In addition, a dual to the optimal estimate of
strain is derived. This dual is constructed to contain no gravitational wave
signature and can thus be used as on "off-source" measurement to test
algorithms used in the "on-source" observation.Comment: 14 pages, 4 figures, submitted to Physical Review D Resubmitted after
editing paper in response to referee comments. Removed appendices A, B and
edited text accordingly. Improved legibility of figures. Corrected several
references. Corrected reference to science run number (S1 vs. S2) in text and
figure caption
Titanium Nitride Films for Ultrasensitive Microresonator Detectors
Titanium nitride (TiNx) films are ideal for use in superconducting
microresonator detectors because: a) the critical temperature varies with
composition (0 < Tc < 5 K); b) the normal-state resistivity is large, \rho_n ~
100 Ohm cm, facilitating efficient photon absorption and providing a large
kinetic inductance and detector responsivity; and c) TiN films are very hard
and mechanically robust. Resonators using reactively sputtered TiN films show
remarkably low loss (Q_i > 10^7) and have noise properties similar to
resonators made using other materials, while the quasiparticle lifetimes are
reasonably long, 10-200 s. TiN microresonators should therefore reach
sensitivities well below 10^-19 WHz^(-1/2).Comment: to be published in AP
The sedimentary imprint of Pleistocene glacio-eustasy: Implications for global correlations of seismic sequences
We evaluate lithofacies, chronology, and seismic sequences from the Canterbury Basin, New Zealand passive continental slope (Integrated Ocean Drilling Program [IODP] Expedition 317 Site U1352 and environs) and compare this with slope sequences from the New Jersey passive margin. Our goal is to understand continental slope sedimentation in response to glacio-eustasy and test the concepts of sequence stratigraphy. High-resolution geochemical elemental and lithostratigraphic analyses were calibrated to a chronology constructed from benthic foramininferal oxygen isotopes for the past ~1.8 m.y. We identify lithofacies successions by their unique geochemical and lithologic signature and correlate them with marine isotope stages (MIS) at Milankovitch 100 k.y. (MIS 1â12) and 41 k.y. (MIS 13â63) periods. Eight seismic sequence boundaries (U13âU19) were identified from high-resolution multichannel seismic data, providing a seismic stratigraphic framework. Except for MIS 1â5 and MIS 54â55, there are 2â16 MIS stages and a comparable number of lithofacies contained within each seismic sequence, indicating that it took one to several glacio-eustatic cycles to build each seismic stratigraphic sequence. These findings support prior results obtained by the Ocean Drilling Program (ODP) Leg 174A on the New Jersey continental slope. On both margins, there is a strong correlation between seismic sequences, lithofacies, and MIS, thus linking them to glacio-eustasy. However, the correlation between MIS and seismic sequences is not one-to-one, and Pleistocene seismic sequences on the two margins are not synchronous. Local conditions, including differences in sedimentation rates and creation of accommodation space, strongly influenced sediment preservation at each location, revealing that high-frequency Pleistocene seismic sequences need not correlate globally
Management to improve soil productivity and maximise lateral infiltration in permanent bed-furrow irrigation systems
The practice of conservation agriculture has been accepted for some time as conventional wisdom for improving soil conditions and raising the soil organic carbon levels of cropping land. This has been complemented over the past 10 years by controlled traffic agriculture, which has further improved soil management practices by almost eliminating compaction as a form of soil degradation.
Not withstanding the improved soil conditions that result from the practice of controlled traffic conservation agriculture, soils minimally tilled by such practices are still subject to consolidation through wetting and drying cycles. In this paper we report on a technique that further improves on these conservative soil management practices. This technique loosens soil at depth without any inversion,
and we examine the consequences this has on the proliferation and distribution of roots, the contents and
distributions of soil organic carbon and total soil nitrogen, the productivity of cropping soils and the lateral
infiltration of irrigation water in permanent bed-furrow systems. Results are drawn from experimental sites in Western Australia, Queensland and Pakistan
TRECVID 2004 experiments in Dublin City University
In this paper, we describe our experiments for TRECVID 2004 for the Search task. In the interactive search task, we developed two versions of a video search/browse system based on the FĂschlĂĄr Digital Video System: one with text- and image-based searching (System A); the other with only image (System B). These two systems produced eight interactive runs. In addition we submitted ten fully automatic supplemental runs and two manual runs.
A.1, Submitted Runs:
⢠DCUTREC13a_{1,3,5,7} for System A, four interactive runs based on text and image evidence.
⢠DCUTREC13b_{2,4,6,8} for System B, also four interactive runs based on image evidence alone.
⢠DCUTV2004_9, a manual run based on filtering faces from an underlying text search engine for certain queries.
⢠DCUTV2004_10, a manual run based on manually generated queries processed automatically.
⢠DCU_AUTOLM{1,2,3,4,5,6,7}, seven fully automatic runs based on language models operating over ASR text transcripts and visual features.
⢠DCUauto_{01,02,03}, three fully automatic runs based on exploring the benefits of multiple sources of text evidence and automatic query expansion.
A.2, In the interactive experiment it was confirmed that text and image based retrieval outperforms an image-only system. In the fully automatic runs, DCUauto_{01,02,03}, it was found that integrating ASR, CC and OCR text into the text ranking outperforms using ASR text alone. Furthermore, applying automatic query expansion to the initial results of ASR, CC, OCR text further increases performance (MAP), though not at high rank positions. For the language model-based fully automatic runs, DCU_AUTOLM{1,2,3,4,5,6,7}, we found that interpolated language models perform marginally better than other tested language models and that combining image and textual (ASR) evidence was found to marginally increase performance (MAP) over textual models alone. For our two manual runs we found that employing a face filter disimproved MAP when compared to employing textual evidence alone and that manually generated textual queries improved MAP over fully automatic runs, though the improvement was marginal.
A.3, Our conclusions from our fully automatic text based runs suggest that integrating ASR, CC and OCR text into the retrieval mechanism boost retrieval performance over ASR alone. In addition, a text-only Language Modelling approach such as DCU_AUTOLM1 will outperform our best conventional text search system. From our interactive runs we conclude that textual evidence is an important lever for locating relevant content quickly, but that image evidence, if used by experienced users can aid retrieval performance.
A.4, We learned that incorporating multiple text sources improves over ASR alone and that an LM approach which integrates shot text, neighbouring shots and entire video contents provides even better retrieval performance. These findings will influence how we integrate textual evidence into future Video IR systems. It was also found that a system based on image evidence alone can perform reasonably and given good query images can aid retrieval performance
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