846 research outputs found

    Sperm whale behaviour indicates the use of echolocation click buzzes 'creaks' in prey capture

    Get PDF
    Author Posting. © Royal Society, 2004. This article is posted here by permission of Royal Society for personal use, not for redistribution. The definitive version was published in Proceedings of the Royal Society of London B 271 (2004): 2239-2247, doi:10.1098/rspb.2004.2863.During foraging dives, sperm whales (Physeter macrocephalus) produce long series of regular clicks at 0.5-2 s intervals interspersed with rapid-click buzzes called 'creaks'. Sound, depth and orientation recording Dtags were attached to 23 whales in the Ligurian Sea and Gulf of Mexico to test whether the behaviour of diving sperm whales supports the hypothesis that creaks are produced during prey capture. Sperm whales spent most of their bottom time within one or two depth bands, apparently feeding in vertically stratified prey layers. Creak rates were highest during the bottom phase: 99.8% of creaks were produced in the deepest 50% of dives, 57% in the deepest 15% of dives. Whales swam actively during the bottom phase, producing a mean of 12.5 depth inflections per dive. A mean of 32% of creaks produced during the bottom phase occurred within 10 s of an inflection (13× more than chance). Sperm whales actively altered their body orientation throughout the bottom phase with significantly increased rates of change during creaks, reflecting increased manoeuvring. Sperm whales increased their bottom foraging time when creak rates were higher. These results all strongly support the hypothesis that creaks are an echolocation signal adapted for foraging, analogous to terminal buzzes in taxonomically diverse echolocating species.Funding for the research was provided under grant #N00014-99-1-0819 from the Office of Naval Research, and Minerals Management Service Cooperative Agreements 1435-01-02-CA-85186 and NA87RJ0445. The Royal Society provided fellowship support to P.J.O.M

    Parents’ experiences of transition from hospital to home after their infant’s first stage cardiac surgery: psychological, physical, physiological and financial survival

    Get PDF
    Background: The inter-surgical stage is a critical time for fragile infants with complex congenital heart disease (CHD) but little is known about the impact on parents. Objective: To explore parents’ experiences of the transition from hospital to home with their infant, following stage one cardiac surgery for complex CHD. Method: A prospective longitudinal mixed methods feasibility study using semi-structured interviews and self-report instruments at four timepoints: before discharge (baseline), 2 weeks post discharge, 8 weeks post discharge and after stage two surgery. Qualitative data were analysed thematically and quantitative data descriptively, Results: Sixteen parents of 12 infants participated. All parents described signs of acute stress disorder; four parents described symptoms of post-traumatic stress disorder before discharge. Parents’ fear and uncertainty about going home was multi-faceted, underpinned by exposure to numerous traumatic events. By 8 weeks post-discharge, parents’ feelings and emotions were positive, relieved and relaxed. Mean generalised anxiety and depression scores were higher before discharge; most individual anxiety and depression scores decreased over time. Physiological survival included self- care needs, eating and sleeping properly. Physical survival included preparation of the home environment and home alterations adapting to their infant’s equipment needs. Financial survival was a burden, particularly for those unable to return to work. Conclusion: Patterns of experience in surviving the transition included psychological, physical, physiological and financial factors. Further longitudinal research could test the effectiveness of psychological preparation interventions, whilst encouraging early consideration of the other factors influencing parents’ care of their infant following discharge from hospital

    BOOTSTRAP ESTIMATION AND COMPARISON OF AN INDEX OF PHYLOGENETIC CORRELATION

    Get PDF
    A common objective of bioinformatic analyses is to assess the similarity of species, given a biological trait or characteristic. Phylogenetic correlation is one means to achieve this objective. Such measures provide a means to evaluate evolutionary models and history as well as having potential application to ecological relationships including host preference selection. Typically, these measurements are based on the deviation of an observed phylogeny from a Brownian evolutionary model. Statistical inference for this difference is assessed through likelihood ratio tests. These tests, in turn, rely on the assumption of a Normal likelihood within the phylogenetic trait. In addition, statistical comparison of estimated phylogenetic correlations between competing phylogenies or traits has not been addressed. In this paper, a bootstrap resampling methodology is proposed for two common phylogenetic correlation metrics, Pagel’s λ and Blomberg’s K. The underlying bootstrap distribution of the estimates will be utilized as a means of computing confidence limits as well as carrying out hypothesis testing. The method will be demonstrated using phylogenetic and metabolomic data related to the host specificity of an insect, Ceutorhynchus cardariae Korotyaev, on a wide range of Brassicaceae species

    The delay-reward heuristic: What do people expect in intertemporal choice tasks?

    Get PDF
    Recent research has shown that risk and reward are positively correlated in many environments, and that people have internalized this association as a "risk-reward heuristic": when making choices based on incomplete information, people infer probabilities from payoffs and vice-versa, and these inferences shape their decisions. We extend this work by examining people's expectations about another fundamental trade-off-that between monetary reward and delay. In 2 experiments (total N = 670), we adapted a paradigm previously used to demonstrate the risk-reward heuristic. We presented participants with intertemporal choice tasks in which either the delayed reward or the length of the delay was obscured. Participants inferred larger rewards for longer stated delays, and longer delays for larger stated rewards; these inferences also predicted people's willingness to take the delayed option. In exploratory analyses, we found that older participants inferred longer delays and smaller rewards than did younger ones. All of these results replicated in 2 large-scale pre-registered studies with participants from a different population (total N = 2138). Our results suggest that people expect intertemporal choice tasks to offer a trade-off between delay and reward, and differ in their expectations about this trade-off. This "delay-reward heuristic" offers a new perspective on existing models of intertemporal choice and provides new insights into unexplained and systematic individual differences in the willingness to delay gratification

    Evaluating on-land capture methods for monitoring a recently rediscovered seabird, the New Zealand Storm-Petrel Fregetta maoriana

    Get PDF
    We provide a first assessment of various on-land capture methods for a procellarid seabird, the New Zealand Storm-Petrel Fregetta maoriana, which had been presumed extinct but for which a breeding site has just been discovered on Little Barrier Island. In the vicinity of an active breeding site, playback only, also involving a newly isolated call from in situ deployed sound-recording devices, could efficiently be employed for capture, while light attraction in combination with playback achieved comparable capture success further afield. We consider that these findings can be relevant for breeding ground searches and capture operations in other storm-petrel species, and more generally in seabirds that visit their breeding sites at night

    Flight Programs and X-ray Optics Development at MSFC

    Get PDF
    The X-ray astronomy group at the Marshall Space Flight Center is developing electroformed nickel/cobalt x-ray optics for suborbital and orbital experiments. Suborbital instruments include the Focusing X-ray Solar Imager (FOXSI) and Micro-X sounding rocket experiments and the HERO balloon payload. Our current orbital program is the fabrication of a series of mirror modules for the Astronomical Roentgen Telescope (ART) to be launched on board the Russian-German Spectrum Roentgen Gamma Mission (SRG.) The details and status of these various programs are presented. A second component of our work is the development of fabrication techniques and optical metrology to improve the angular resolution of thin shell optics to the arcsecond-level. The status of these x-ray optics technology developments is also presented

    A case of natural recovery after the removal of invasive predators – community assemblage changes in the avifauna of Burgess Island

    Get PDF
    Opportunities to monitor natural island ecosystem recovery following the eradication of introduced predators are rare, and provide a useful comparison for recovery programmes aided by active habitat restoration and species translocations. We present an assessment of the current avifauna on Burgess Island, Mokohinau Group, 2 decades after kiore (Pacific rat; Rattus exulans) removal. The 4 most abundant land bird species we recorded are red-crowned parakeet (Cyanorhamphus novaezelandiae), bellbird (Anthornis melanura), tui (Prosthemadera novaeseelandiae) and silvereye (Zosterops lateralis), all New Zealand native taxa. Our records confirm that 46 species now utilize the island’s habitats, compared with 24 species reported from the literature during the last decades of rat infestation. We also confirm breeding of 9 seabird species by 2011, only 4 of which maintained breeding populations on Burgess Island prior to rat eradication. More than 20 years after predator removal, Burgess Island hosts a rich avifauna, and provides a valuable example of natural recovery following predator eradication without any further active restoration measure
    • …
    corecore