228 research outputs found
The provenance, date and significance of a Cook-voyage Polynesian sculpture
A unique wooden sculpture collected by James Cook during his first voyage to the Pacific is widely considered to be a masterpiece of Oceanic art, but its exact provenance has been unclear. New analysis of shavings from the object now indicate that a) the tree from which it was carved was felled between 1690 and 1728, and that the carving was therefore up to 80 years old when obtained, and b) it originated in Tahiti, despite its stylistic affinities with art from the Austral Islands. Motifs and forms clearly travelled within regions, and populations interacted in ways that blur presumed tribal boundaries. It is perhaps time to reconsider the association between region and style upon which the cataloguing and identification of objects routinely depends.The research reported upon here has taken place in the context of two projects, 'Artefacts of Encounter', funded by the UK Arts and Humanities Research Council over 2010-13, and 'Pacific Presences', funded by the European Research Council over 2013-18. We are grateful to both agencies for their support. We also thank: Julie Adams (British Museum); Peter Brunt (Victoria University); Caroline Cartwright (British Museum); Steven Hooper (University of East Anglia); JeanYves Meyer (MinistĂšre des Ressources Marines, des Mines et de la Recherche, PolynĂ©sie Française); Mark Nesbitt (Economic Botany Collection, Royal Botanic Gardens, Kew); Tamsin OâConnell (Dorothy Garrod Laboratory for Isotopic Analysis, McDonald Institute for Archaeological Research); Jessica Royles (Department of Plant Sciences, University of Cambridge); Matthew Spriggs (Australian National University); and the University of Oxford Radiocarbon Accelerator Unit
Severe consequences of habitat fragmentation on genetic diversity of an endangered Australian freshwater fish: A call for assisted gene flow
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium,
provided the original work is properly cited.Genetic diversity underpins the ability of populations to persist and adapt to environmental changes. Substantial empirical data show that genetic diversity rapidly deteriorates in small and isolated populations due to genetic drift, leading to reduction in adaptive potential and fitness and increase in inbreeding. Assisted gene flow (e.g. via translocations) can reverse these trends, but lack of data on fitness loss and fear of impairing population âuniquenessâ often prevents managers from acting. Here, we use population genetic and riverscape genetic analyses and simulations to explore the consequences of extensive habitat loss and fragmentation on population genetic diversity and future population trajectories of an endangered Australian freshwater fish, Macquarie perch Macquaria australasica. Using guidelines to assess the risk of outbreeding depression under admixture, we develop recommendations for population management, identify populations requiring genetic rescue and/or genetic restoration and potential donor sources. We found that most remaining populations of Macquarie perch have low genetic diversity, and effective population sizes below the threshold required to retain adaptive potential. Our simulations showed that under management inaction, smaller populations of Macquarie perch will face inbreeding depression within a few decades, but regular small-scale translocations will rapidly rescue populations from inbreeding depression and increase adaptive potential through genetic restoration. Despite the lack of data on fitness loss, based on our genetic data for Macquarie perch populations, simulations and empirical results from other systems, we recommend regular and frequent translocations among remnant populations within catchments. These translocations will emulate the effect of historical gene flow and improve population persistence through decrease in demographic and genetic stochasticity. Increasing population genetic connectivity within each catchment will help to maintain large effective population sizes and maximize species adaptive potential. The approach proposed here could be readily applicable to genetic management of other threatened species to improve their adaptive potential
Recommended from our members
Fuel Cycle Scenario Definition, Evaluation, and Trade-offs
This report aims to clarify many of the issues being discussed within the AFCI program, including Inert Matrix Fuel (IMF) versus Mixed Oxide (MOX) fuel, single-pass versus multi-pass recycling, thermal versus fast reactors, potential need for transmutation of technetium and iodine, and the value of separating cesium and strontium. It documents most of the work produced by INL, ANL, and SNL personnel under their Simulation, Evaluation, and Trade Study (SETS) work packages during FY2005 and the first half of FY2006. This report represents the first attempt to calculate a full range of metrics, covering all four AFCI program objectives - waste management, proliferation resistance, energy recovery, and systematic management/economics/safety - using a combination of "static" calculations and a system dynamic model, DYMOND. In many cases, we examine the same issue both dynamically and statically to determine the robustness of the observations. All analyses are for the U.S. reactor fleet. This is a technical report, not aimed at a policy-level audience. A wide range of options are studied to provide the technical basis for identifying the most attractive options and potential improvements. Option improvement could be vital to accomplish before the AFCI program publishes definitive cost estimates. Information from this report will be extracted and summarized in future policy-level reports. Many dynamic simulations of deploying those options are included. There are few "control knobs" for flying or piloting the fuel cycle system into the future, even though it is dark (uncertain) and controls are sluggish with slow time response: what types of reactors are built, what types of fuels are used, and the capacity of separation and fabrication plants. Piloting responsibilities are distributed among utilities, government, and regulators, compounding the challenge of making the entire system work and respond to changing circumstances. We identify four approaches that would increase our ability to pilot the fuel cycle system: (1) have a recycle strategy that could be implemented before the 2030-2050 approximate period when current reactors retire so that replacement reactors fit into the strategy, (2) establish an option such as multi-pass blended-core IMF as a downward plutonium control knob and accumulate waste management benefits early, (3) establish fast reactors with flexible conversion ratio as a future control knob that slowly becomes available if/when fast reactors are added to the fleet, and (4) expand exploration of blended assemblies and cores, which appear to have advantages and agility. Initial results suggest multi-pass full-core MOX appears to be a less effective way than multi-pass blended core IMF to manage the fuel cycle system because it requires higher TRU throughput while more slowly accruing waste management benefits. Single-pass recycle approaches for LWRs (we did not study the VHTR) do not meet AFCI program objectives and could be considered a "dead end". Fast reactors appear to be effective options but a significant number of fast reactors must be deployed before the benefit of such strategies can be observed
Troubling Places: Walking the âtroubling remnantsâ of postâconflict space
This paper explores the productive potential of walking methods in postâconflict space, with particular emphasis on Northern Ireland. We argue that walking methods are especially well suited to studying postâconflict spatial arrangements, yet remain underutilised for a variety of reasons. Specifically, we argue that walking methods can âtroubleâ dominant productions of postâconflict space, revealing its storied depth, multiâtemporality, and the alternative narratives of the past that frequently remain hidden in places touched by violence. Critically, employing such placeâsensitive approaches challenges âbad scriptsâ that reify polarised narratives of conflicted places, thereby enabling the writing of new spatial stories that are potentially generative of new research questions and scholarly insights rooted in overlooked, marginalised, or takenâforâgranted people, places, and landscapes. Informed by both authors' ongoing research journeys, we argue that walking in troubled places can help scholars dig into the reservoirs of emotion, affect, vitality, and multiâtemporality people experience in postâconflict landscapes, thus opening up new research vistas in places scholars might not have sought to look using only sedentary methods.</jats:p
SNAP-25 Palmitoylation and Plasma Membrane Targeting Require a Functional Secretory Pathway
The Ankyrin Repeats and DHHC S-acyl Transferase Domain of AKR1 Act Independently to Regulate Switching from Vegetative to Mating States in Yeast
Signal transduction from G-protein coupled receptors to MAPK cascades through heterotrimeric G-proteins has been described for many eukaryotic systems. One of the best-characterised examples is the yeast pheromone response pathway, which is negatively regulated by AKR1. AKR1-like proteins are present in all eukaryotes and contain a DHHC domain and six ankyrin repeats. Whilst the DHHC domain dependant S-acyl transferase (palmitoyl transferase) function of AKR1 is well documented it is not known whether the ankyrin repeats are also required for this activity. Here we show that the ankyrin repeats of AKR1 are required for full suppression of the yeast pheromone response pathway, by sequestration of the GÎČÎł dimer, and act independently of AKR1 S-acylation function. Importantly, the functions provided by the AKR1 ankyrin repeats and DHHC domain are not required on the same molecule to fully restore WT phenotypes and function. We also show that AKR1 molecules are S-acylated at locations other than the DHHC cysteine, increasing the abundance of AKR1 in the cell. Our results have important consequences for studies of AKR1 function, including recent attempts to characterise S-acylation enzymology and kinetics. Proteins similar to AKR1 are found in all eukaryotes and our results have broad implications for future work on these proteins and the control of switching between GÎČÎł regulated pathways
Five areas to advance branding theory and practice
The paper suggests five areas to advance branding theory and practice based on the authorsâ recent work in brand management.
In this commentary, we aim to put forward suggestions and ideas for further research in brand management; ideas, which we believe will have an impact on the way branding is researched and practiced by both academics and practitioners alike. We will focus on the future of branding in the following areas, inspired by our own work in the field: (1) branding in higher education, (2) branding in Asia Pacific, (3) brand ambidexterity, (4) brand innovation on social media, and (5) brand likeability
District-Level Spatial Analysis of Migration Flows in Ghana: Determinants and Implications for Policy
Characterization of important odorants in four steamed Coilia ectenes from China by gas chromatographyâmass spectrometryâolfactometry
- âŠ