374 research outputs found

    Behavioural Response Thresholds in New Zealand Crab Megalopae to Ambient Underwater Sound

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    A small number of studies have demonstrated that settlement stage decapod crustaceans are able to detect and exhibit swimming, settlement and metamorphosis responses to ambient underwater sound emanating from coastal reefs. However, the intensity of the acoustic cue required to initiate the settlement and metamorphosis response, and therefore the potential range over which this acoustic cue may operate, is not known. The current study determined the behavioural response thresholds of four species of New Zealand brachyuran crab megalopae by exposing them to different intensity levels of broadcast reef sound recorded from their preferred settlement habitat and from an unfavourable settlement habitat. Megalopae of the rocky-reef crab, Leptograpsus variegatus, exhibited the lowest behavioural response threshold (highest sensitivity), with a significant reduction in time to metamorphosis (TTM) when exposed to underwater reef sound with an intensity of 90 dB re 1 µPa and greater (100, 126 and 135 dB re 1 µPa). Megalopae of the mud crab, Austrohelice crassa, which settle in soft sediment habitats, exhibited no response to any of the underwater reef sound levels. All reef associated species exposed to sound levels from an unfavourable settlement habitat showed no significant change in TTM, even at intensities that were similar to their preferred reef sound for which reductions in TTM were observed. These results indicated that megalopae were able to discern and respond selectively to habitat-specific acoustic cues. The settlement and metamorphosis behavioural response thresholds to levels of underwater reef sound determined in the current study of four species of crabs, enables preliminary estimation of the spatial range at which an acoustic settlement cue may be operating, from 5 m to 40 km depending on the species. Overall, these results indicate that underwater sound is likely to play a major role in influencing the spatial patterns of settlement of coastal crab species

    Computational study of structural and elastic properties of random AlGaInN alloys

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    In this work we present a detailed computational study of structural and elastic properties of cubic AlGaInN alloys in the framework of Keating valence force field model, for which we perform accurate parametrization based on state of the art DFT calculations. When analyzing structural properties, we focus on concentration dependence of lattice constant, as well as on the distribution of the nearest and the next nearest neighbour distances. Where possible, we compare our results with experiment and calculations performed within other computational schemes. We also present a detailed study of elastic constants for AlGaInN alloy over the whole concentration range. Moreover, we include there accurate quadratic parametrization for the dependence of the alloy elastic constants on the composition. Finally, we examine the sensitivity of obtained results to computational procedures commonly employed in the Keating model for studies of alloys

    Disease surveillance and risk factors affecting mortality of captive cirl buntings (Emberiza cirlus) in a translocation for conservation purposes

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    Cirl buntings in the UK were translocated over a 5-year period by collecting chicks from the residual population, hand-rearing and releasing them at a site in Cornwall with the aim of establishing a second breeding population. Because mortality and morbidity during captivity restrict the number and fitness of individuals available for release, selected parasites were monitored in the captive chicks, and all deaths were investigated by autopsy, histopathology and bacteriology. Risk factors associated with captive deaths were analysed. Annual mortality during captivity ranged from 4% (3 of 75 chicks in 2006) to 42% (26 of 73 in 2007) of chicks collected. Infectious disease associated with immunosuppression was an important factor in many deaths, and chicks collected with lower body weight were at greater risk of mortality. These findings emphasise the need for rigorous monitoring of all aspects of captive care during passerine translocations and provide evidence-based recommendations for future projects

    INFX GUIDE: DEPARTMENT OF ENERGY BILATERAL AGREEMENTS FOR COOPERATION IN THE FIELD OF RADIOACTIVE WASTE MANAGEMENT (INFX: INTERNATIONAL INFORMATION EXCHANGE)

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    As the U. S. Department of Energy (DOE) and DOE contractors have increased the magnitude and scope of their cooperative activities with other nations in the nuclear fuel cycle and waste management field, a need has developed for ready sources of information concerning foreign waste management programs, DOE technology exchange policies, bilateral fuel cycle and waste management agreements and plans and activities to implement those agreements. The INFX (International InLormation E~change) Guide is one of a series of documents that have been prepared to provide that information. The INFX Guide has been compiled under the charter of PNL's International Support Office (IPSO) to maintain for DOE a center to collect, organize, evaluate and disseminate information on foreign and international radioactive waste management programs. Because the information in this document is constantly subject to change, the document is assembled in loose-leaf form to accommodate frequent updates

    Fussy Feeders: Phyllosoma Larvae of the Western Rocklobster (Panulirus cygnus) Demonstrate Prey Preference

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    The Western Rocklobster (Panulirus cygnus) is the most valuable single species fishery in Australia and the largest single country spiny lobster fishery in the world. In recent years a well-known relationship between oceanographic conditions and lobster recruitment has become uncoupled, with significantly lower recruitment than expected, generating interest in the factors influencing survival and development of the planktonic larval stages. The nutritional requirements and wild prey of the planktotrophic larval stage (phyllosoma) of P. cygnus were previously unknown, hampering both management and aquaculture efforts for this species. Ship-board feeding trials of wild-caught mid-late stage P. cygnus phyllosoma in the eastern Indian Ocean, off the coast of Western Australia, were conducted in July 2010 and August-September 2011. In a series of experiments, phyllosoma were fed single and mixed species diets of relatively abundant potential prey items (chaetognaths, salps, and krill). Chaetognaths were consumed in 2–8 times higher numbers than the other prey, and the rate of consumption of chaetognaths increased with increasing concentration of prey. The highly variable lipid content of the phyllosoma, and the fatty acid profiles of the phyllosoma and chaetognaths, indicated they were from an oligotrophic oceanic food chain where food resources for macrozooplankton were likely to be constrained. Phyllosoma fed chaetognaths over 6 days showed significant changes in some fatty acids and tended to accumulate lipid, indicating an improvement in overall nutritional condition. The discovery of a preferred prey for P. cygnus will provide a basis for future oceanographic, management and aquaculture research for this economically and ecologically valuable species

    Speaking Up for Fundamental Care: the ILC Aalborg Statement.

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    OBJECTIVE: The International Learning Collaborative (ILC) is an organisation dedicated to understanding why fundamental care, the care required by all patients regardless of clinical condition, fails to be provided in healthcare systems globally. At its 11th annual meeting in 2019, nursing leaders from 11 countries, together with patient representatives, confirmed that patients' fundamental care needs are still being ignored and nurses are still afraid to 'speak up' when these care failures occur. While the ILC's efforts over the past decade have led to increased recognition of the importance of fundamental care, it is not enough. To generate practical, sustainable solutions, we need to substantially rethink fundamental care and its contribution to patient outcomes and experiences, staff well-being, safety and quality, and the economic viability of healthcare systems. KEY ARGUMENTS: We present five propositions for radically transforming fundamental care delivery:Value: fundamental care must be foundational to all caring activities, systems and institutionsTalk: fundamental care must be explicitly articulated in all caring activities, systems and institutions.Do: fundamental care must be explicitly actioned and evaluated in all caring activities, systems and institutions.Own: fundamental care must be owned by each individual who delivers care, works in a system that is responsible for care or works in an institution whose mission is to deliver care. RESEARCH: fundamental care must undergo systematic and high-quality investigations to generate the evidence needed to inform care practices and shape health systems and education curricula. CONCLUSION: For radical transformation within health systems globally, we must move beyond nursing and ensure all members of the healthcare team-educators, students, consumers, clinicians, leaders, researchers, policy-makers and politicians-value, talk, do, own and research fundamental care. It is only through coordinated, collaborative effort that we will, and must, achieve real change

    A Gene Expression Signature of Invasive Potential in Metastatic Melanoma Cells

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    BACKGROUND: We are investigating the molecular basis of melanoma by defining genomic characteristics that correlate with tumour phenotype in a novel panel of metastatic melanoma cell lines. The aim of this study is to identify new prognostic markers and therapeutic targets that might aid clinical cancer diagnosis and management. PRINCIPAL FINDINGS: Global transcript profiling identified a signature featuring decreased expression of developmental and lineage specification genes including MITF, EDNRB, DCT, and TYR, and increased expression of genes involved in interaction with the extracellular environment, such as PLAUR, VCAN, and HIF1a. Migration assays showed that the gene signature correlated with the invasive potential of the cell lines, and external validation by using publicly available data indicated that tumours with the invasive gene signature were less melanocytic and may be more aggressive. The invasion signature could be detected in both primary and metastatic tumours suggesting that gene expression conferring increased invasive potential in melanoma may occur independently of tumour stage. CONCLUSIONS: Our data supports the hypothesis that differential developmental gene expression may drive invasive potential in metastatic melanoma, and that melanoma heterogeneity may be explained by the differing capacity of melanoma cells to both withstand decreased expression of lineage specification genes and to respond to the tumour microenvironment. The invasion signature may provide new possibilities for predicting which primary tumours are more likely to metastasize, and which metastatic tumours might show a more aggressive clinical course

    Phyllosomata associated with large gelatinous zooplankton: hitching rides and stealing bites

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    During a zooplankton survey 350 km off the coast of Western Australia, we captured a large and robust zooid of a salp (Thetys vagina), to which six late stage larvae (phyllosomata) of the western rock lobster (Panulirus cygnus) were attached. High-throughput sequencing analyses of DNA extracts from midgut glands of the larvae confirmed that each phyllosoma had consumed mainly salp tissue ( x 1⁄4 64.5% + 15.9 of DNA reads). These results resolve long-standing conjecture whether spiny lobster phyllosomata attach to large gelatinous hosts to feed on them
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