1,135 research outputs found
Utilisation of intensive foraging zones by female Australian fur seals.
Within a heterogeneous environment, animals must efficiently locate and utilise foraging patches. One way animals can achieve this is by increasing residency times in areas where foraging success is highest (area-restricted search). For air-breathing diving predators, increased patch residency times can be achieved by altering both surface movements and diving patterns. The current study aimed to spatially identify the areas where female Australian fur seals allocated the most foraging effort, while simultaneously determining the behavioural changes that occur when they increase their foraging intensity. To achieve this, foraging behaviour was successfully recorded with a FastLoc GPS logger and dive behaviour recorder from 29 individual females provisioning pups. Females travelled an average of 118 ± 50 km from their colony during foraging trips that lasted 7.3 ± 3.4 days. Comparison of two methods for calculating foraging intensity (first-passage time and first-passage time modified to include diving behaviour) determined that, due to extended surface intervals where individuals did not travel, inclusion of diving behaviour into foraging analyses was important for this species. Foraging intensity 'hot spots' were found to exist in a mosaic of patches within the Bass Basin, primarily to the south-west of the colony. However, the composition of benthic habitat being targeted remains unclear. When increasing their foraging intensity, individuals tended to perform dives around 148 s or greater, with descent/ascent rates of approximately 1.9 m•s-1 or greater and reduced postdive durations. This suggests individuals were maximising their time within the benthic foraging zone. Furthermore, individuals increased tortuosity and decreased travel speeds while at the surface to maximise their time within a foraging location. These results suggest Australian fur seals will modify both surface movements and diving behaviour to maximise their time within a foraging patch
Neutron-rich nuclei in cosmic rays and Wolf-Rayet stars
Wolf-Rayet stars figure prominently in astrophysical research. As a bonus, they seem to offer, in the recent past, an interesting connection between classical astronomy and high energy astrophysics due to their unusual composition and their huge mechanical power. The material flowing from WC stars (carbon-rich WR stars) contains gas which has been processed through core-helium burning, i.e., considerably enriched into 12C,16O, 22Ne, and 25,26Mg. This composition is reminiscent of the cosmic ray source anomalies. Encouraging agreement is obtained with observation in the mass range 12 A 26 assuming acceleration of wind particles at the shock that delineates the WR cavity, and adequate dilution with normal cosmic rays, but silicon poses
Low-Energy Direct Capture in the 16O(alpha,gamma)20Ne Reaction
The cross section of the 16O(a,g)20Ne capture reaction is analyzed at low
energies where the direct capture mechanism is dominant. For temperatures below
T9 = 0.2 the resulting astrophysical reaction rate is about a factor of two
higher than in a recent compilation whereas the energy dependence of the
astrophysical S-factor and the branching ratios to the 20Ne bound states are
very similar to previous calculations. The validity of the widely used detailed
balance theorem for the inverse 20Ne(g,a)16O photodisintegration rate is
confirmed for the special case of high-lying first excited states.Comment: 11 pages, 4 figures, Phys. Rev. C, accepted for publicatio
Validating accelerometry-derived proxies of energy expenditure using the doubly-labelled water method in the smallest penguin species
Acknowledgements We are grateful to Dr Catherine Hambly and Peter Thompson for technical assistance with the isotope analysis for the doubly labelled water measurements. We thank Parks Victoria (in particular, the rangers at Gabo Island and Port Campbell Offices) and Kevin Lotte for logistical support. Funding This project was funded by the Holsworth Wildlife Research Endowment – Equity Trustees Charitable Foundation and the Ecological Society of Australia and Deakin University internal funds.Peer reviewedPublisher PD
Selective demarketing: When customers destroy value.
Selective demarketing is a strategic option for firms to manage customers who are or are likely to be a poor fit with its offering. Research has investigated related areas such as customer profitability and relationship dissolution but, as yet, studies have not offered a robust conceptualisation of selective demarketing. Based on research into value co-destruction, this study argues that these customers effectively destroy value by misusing or misunderstanding how to integrate their operant resources with those of the firm. As firms exist within a wider service system, this failure to integrate resonates throughout the system. To demarket selectively, firms use higher order operant resources to disengage and discourage these customers. This study offers a novel conceptualisation of selective demarketing and extends research on value destruction through adopting a firm and systems perspective
Determining energy expenditure in a large seabird using accelerometry
Funding The research was financially supported by the Holsworth Wildlife Research Endowment. Open Access funding provided by La Trobe University. Deposited in PMC for immediate release. Acknowledgements We thank the Victorian Marine Science Consortium, Sea All Dolphin Swims, and Parks Victoria for logistical support. Catherine Hambly and Peter Thomson provided technical support for the DLW isotope analysis. Aspects of the results and discussion in this paper are reproduced from the PhD thesis of L.P.A. (Angel, 2015).Peer reviewedPublisher PD
Making space for experiences
Leisure and retail providers need to understand the elements of the visitor experience and the way in which they evaluate their satisfaction. This article suggests a holistic prism model of the interaction between the management and the visitor in a leisure space. This is applied to a netnographic study of visitors to a folk festival to illustrate the interconnectiveness of the different attributes causing dissatisfaction. It found that the physical and operational attributes were evaluated not through a checklist of individual features but as hindrances to the visitor's desire to make best use of the time. Visitors also evaluated the experience in the light of their own values and concerns, passing judgement on the values communicated by the management. At the heart of the experience was the enjoyment of choosing from an abundant offer and discovering something new. The main attraction is often only the pretext for enjoying the company of friends so places to meet before and chill-out afterwards are vital to the experience. The distinctiveness of the setting, the food and drink can become the sensory cues which give the event or location its uniqueness. The challenge to retail and leisure organisations is to design these elements of a memorable experience into their offerings
Proton capture cross section of Sr isotopes and their importance for nucleosynthesis of proton-rich nuclides
The (p,) cross sections of three stable Sr isotopes have been
measured in the astrophysically relevant energy range. These reactions are
important for the -process in stellar nucleosynthesis and, in addition, the
reaction cross sections in the mass region up to 100 are also of importance
concerning the -process associated with explosive hydrogen and helium
burning. It is speculated that this -process could be responsible for a
certain amount of -nuclei in this mass region. The (p,) cross
sections of Sr isotopes were determined using an activation
technique. The measurements were carried out at the 5 MV Van de Graaff
accelerator of the ATOMKI, Debrecen. The resulting cross sections are compared
with the predictions of statistical model calculations. The predictions are in
good agreement with the experimental results for Sr(p,)Y
whereas the other two reactions exhibit differences that increase with mass
number. The corresponding astrophysical reaction rates have also been computed.Comment: Phys. Rev. C in pres
A search for radioactive 26Al in the nova-like variable V4332 Sagittarii
We have searched for the important radioactive isotope 26Al in the nova-like
source V4332 Sgr. Recent results from gamma ray astronomy show that there is
pervasive emission of the 1.809 MeV gamma ray photon, arising from the decay of
26Al to 26Mg, from all over the galactic plane. Though the sites from where
this emission originates are not clearly established, novae are believed to be
an important contributing source. In this context, V4332 Sgr presented a rare
opportunity to observationally investigate whether novae or novae-like sources
synthesize 26Al and to what extent. Strong AlO bands in the near-IR have been
reported in this object recently. As molecular bands of different isotopic
compositions are readily resolved spectroscopically (e.g. 12CO and 13CO), it
was thought that the components of AlO associated with
26Al and stable 27Al could be detected as separate bands. Our spectra
indicate that there is no strong presence of 26Al in V4332 Sgr. A reliable
upper limit of 0.10 for the 26Al/27Al ratio is determined which constitutes the
first observational constraint for this ratio in a potential 26Al producing
source. While V4332 Sgr is not a typical nova, its outburst amplitude and
light-curve behaviour bear close similarity to that of novae. Hence, although
the results from V4332 Sgr cannot be directly extended to novae in general, the
limit on the observed 26Al/27Al ratio could be a useful input in constraining
rather uncertain nucleosynthesis models for the production of 26Al in
novae/novae-like sources. By comparing the observed 26Al/27Al ratio in V4332
Sgr with that expected in classical novae it appears unlikely that the
progenitor of V4332 Sgr is an Oxygen-Neon-Magnesium white dwarf.Comment: 9 pages, 2 figures, to appear in Ap.J(L) July 200
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