779 research outputs found

    Diving behaviour of whale sharks in relation to a predictable food pulse

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    We present diving data for four whale sharks in relation to a predictable food pulse (reef fish spawn) and an analysis of the longest continuous fine-resolution diving record for a planktivorous shark. Fine-resolution pressure data from a recovered pop-up archival satellite tag deployed for 206 days on a whale shark were analysed using the fast Fourier Transform method for frequency domain analysis of time-series. The results demonstrated that a free-ranging whale shark displays ultradian, diel and circa-lunar rhythmicity of diving behaviour. Whale sharks dive to over 979.5 m and can tolerate a temperature range of 26.4 degrees C. The whale sharks made primarily diurnal deep dives and remained in relatively shallow waters at night. Whale shark diving patterns are influenced by a seasonally predictable food source, with shallower dives made during fish spawning periods

    Conformal Powers of the Laplacian via Stereographic Projection

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    A new derivation is given of Branson's factorization formula for the conformally invariant operator on the sphere whose principal part is the k-th power of the scalar Laplacian. The derivation deduces Branson's formula from knowledge of the corresponding conformally invariant operator on Euclidean space (the k-th power of the Euclidean Laplacian) via conjugation by the stereographic projection mapping

    Access to liquidity and corporate investment in Europe during the financial crisis

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    We use a unique data set to show how firms in Europe used credit lines during the financial crisis. We find that firms with restricted access to credit (small, private, non-investment-grade, and unprofitable) draw more funds from their credit lines during the crisis than their large, public, investment-grade, profitable counterparts. Interest spreads increased (especially in "market-based economies"), but commitment fees remained unchanged. Our findings suggest that credit lines did not dry up during the crisis and provided the liquidity that firms used to cope with this exceptional contraction. In particular, credit lines provided the liquidity companies needed to invest during the crisis

    Characterization of a supercoil-dependent S1 sensitive site 5\u27 to the Drosophila melanogaster hsp 26 gene

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    We have analyzed the prominent supercoil-dependent S1 nuclease cleavage site 5\u27 to hsp 26 in the plasmid 88B13, which contains 11.7 kilobases from the Drosophila locus 67B1. The double stranded cleavage product is generated by initial nicking on the purine strand, six preferred sites occurring between positions -96 and -90 (relative to the start of transcription) with weaker ones extending to position -84, followed by cleavage on the pyrimidine strand at positions -86 and -84. A derivative of 88B13, 88B13-X, was generated by insertion of an Xho I linker at position -84; this does not affect the positions or strand specificity of the S1 cleavage in that region. A small deletion, delta 41.1, removes the homopurine/homopyrimidine stretch from positions -86 to -132 and is no longer sensitive to cleavage by S1 nuclease 5\u27 to hsp 26. Mung bean and P1 nucleases recognize the same site 5\u27 to hsp 26 and give the same general pattern of cleavage. All three nucleases show an initial cleavage of 88B13 DNA at this site at pH 5.5 but not at pH 6.5, indicating that the DNA structure there may be pH dependent in vitro

    Improved traceability in seafood supply chains is achievable by minimising vulnerable nodes in processing and distribution networks

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    Seafood is a globally traded commodity, often involving complex supply chains which have varying degrees of traceability. A robust traceability system for seafood supply chains enables the collection and communication of key information about catch and fisheries origins vital for assurance of the legality and sustainability of seafood products. End-to-end traceability is increasingly demanded by retailers, consumers, NGOs and regulatory bodies to ensure food safety, deter IUU fishing and verify sustainable and ethical credentials. Here, we map three UK seafood supply chains and evaluate traceability performance in: Dover sole landed in the south west of England, North-East Atlantic (NEA) mackerel landed at Peterhead, Scotland, and brown crab and European lobster, landed at Bridlington, England. Through a comparative analysis of traceability performance, this study suggests improvements to the technologies, processes, and systems for traceability in the seafood sector. The application of monitoring technologies and regulatory changes across the sector have increased traceability and potentially reduced instances of IUU fishing. While shorter supply chains are more likely to achieve end-to-end traceability, vulnerable nodes in processing and distribution networks may result in a loss of seafood traceability. While traceability systems may provide sustainability information on seafood, a high level of traceability performance does not necessarily equate to a sustainable source fishery. Encouragingly, while UK seafood supply chains are meeting minimum regulatory requirements for traceability, in the present study, many stakeholders have indicated ambitions towards traceability best practice in order to provide confidence and trust in the UK fishing industry

    Collaboration and co-production knowledge in healthcare: opportunities and challenges

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    Over time there has been a shift, at least in the rhetoric, from a pipeline conceptualisation of knowledge implementation, to one that recognises the potential of more collaboration, co-productive approaches to knowledge production and use. In this editorial, which is grounded in our research and collective experience, we highlight both the potential and challenge with collaboration and co-production. This includes issues about stakeholder engagement, governance arrangements, and capacity and capability for working in a coproductive way. Finally, we reflect on the fact that this approach is not a panacea, but is accompanied by some philosophical and practical challenges

    Optimal heat-induced expression of the Drosophila hsp26 gene requires a promoter sequence containing (CT)n.(GA)n repeats

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    We report here the analysis of the sequence requirements for the heat-induced expression of the Drosophila melanogaster hsp26 gene using germline transformation. Heat-induced expression is augmented fivefold by a homopurine/homopyrimidine region from -85 to -134 that is devoid of heat-shock elements but contains numerous (dC-dT).(dG-dA) repeats. Sequences within this interval have been shown to assume a nuclease S1-hypersensitive structure in vitro. In this paper, we extend those in vitro observations, demonstrating that the S1-hypersensitive structure is triple-helical H-DNA formed by a symmetric (dC-dT).(dG-dA) sequence. Thus, the sequences that form H-DNA in vitro are also required in vivo for optimal hsp26 transcription. However, mutational analysis and diethylpyrocarbonate modification experiments in isolated nuclei suggest that the (dC-dT).(dG-dA) sequence does not form H-DNA in vivo and argue against a role for H-DNA in the heat-induced expression of hsp26

    Wave decay on convex co-compact hyperbolic manifolds

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    For convex co-compact hyperbolic quotients X=\Gamma\backslash\hh^{n+1}, we analyze the long-time asymptotic of the solution of the wave equation u(t)u(t) with smooth compactly supported initial data f=(f0,f1)f=(f_0,f_1). We show that, if the Hausdorff dimension δ\delta of the limit set is less than n/2n/2, then u(t) = C_\delta(f) e^{(\delta-\ndemi)t} / \Gamma(\delta-n/2+1) + e^{(\delta-\ndemi)t} R(t) where Cδ(f)C(X)C_{\delta}(f)\in C^\infty(X) and ||R(t)||=\mc{O}(t^{-\infty}). We explain, in terms of conformal theory of the conformal infinity of XX, the special cases \delta\in n/2-\nn where the leading asymptotic term vanishes. In a second part, we show for all \eps>0 the existence of an infinite number of resonances (and thus zeros of Selberg zeta function) in the strip \{-n\delta-\eps<\Re(\la)<\delta\}. As a byproduct we obtain a lower bound on the remainder R(t)R(t) for generic initial data ff.Comment: 18 page
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