8 research outputs found

    Historical biogeography of the leopard (Panthera pardus) and its extinct Eurasian populations

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    Background: Resolving the historical biogeography of the leopard (Panthera pardus) is a complex issue, because patterns inferred from fossils and from molecular data lack congruence. Fossil evidence supports an African origin, and suggests that leopards were already present in Eurasia during the Early Pleistocene. Analysis of DNA sequences however, suggests a more recent, Middle Pleistocene shared ancestry of Asian and African leopards. These contrasting patterns led researchers to propose a two-stage hypothesis of leopard dispersal out of Africa: an initial Early Pleistocene colonisation of Asia and a subsequent replacement by a second colonisation wave during the Middle Pleistocene. The status of Late Pleistocene European leopards within this scenario is unclear: were these populations remnants of the first dispersal, or do the last surviving European leopards share more recent ancestry with their African counterparts? Results: In this study, we generate and analyse mitogenome sequences from historical samples that span the entire modern leopard distribution, as well as from Late Pleistocene remains. We find a deep bifurcation between African and Eurasian mitochondrial lineages (~ 710 Ka), with the European ancient samples as sister to all Asian lineages (~ 483 Ka). The modern and historical mainland Asian lineages share a relatively recent common ancestor (~ 122 Ka), and we find one Javan sample nested within these. Conclusions: The phylogenetic placement of the ancient European leopard as sister group to Asian leopards suggests that these populations originate from the same out-of-Africa dispersal which founded the Asian lineages. The coalescence time found for the mitochondrial lineages aligns well with the earliest undisputed fossils in Eurasia, and thus encourages a re-evaluation of the identification of the much older putative leopard fossils from the region. The relatively recent ancestry of all mainland Asian leopard lineages suggests that these populations underwent a severe population bottleneck during the Pleistocene. Finally, although only based on a single sample, the unexpected phylogenetic placement of the Javan leopard could be interpreted as evidence for exchange of mitochondrial lineages between Java and mainland Asia, calling for further investigation into the evolutionary history of this subspecies

    REDWIN – REDucing cost in offshore WINd by integrated structural and geotechnical design

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    The cost of offshore wind energy production has to be reduced continuously to improve its competitiveness compared to other energy sources. To contribute to this goal, a 4- year research project REDWIN – REDucing cost of offshore WINd by structural and geotechnical integrated design – is currently ongoing, addressing the challenge of integrating the geotechnical discipline in the design process. The project aims to develop foundation and soil models to be used in dynamic time-domain analyses of offshore wind turbine structures. A library of models has been developed for representation of the most common foundation types. The models can be applied to different ground conditions by site-specific model input. To make the models applicable for practical usage, it has been important to balance the need for computational effectiveness against the need for accuracy. Studies so far indicate that the foundation models improve the accuracy in the integrated analyses.publishedVersio

    REDWIN – REDucing cost in offshore WINd by integrated structural and geotechnical design

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    The cost of offshore wind energy production has to be reduced continuously to improve its competitiveness compared to other energy sources. To contribute to this goal, a 4- year research project REDWIN – REDucing cost of offshore WINd by structural and geotechnical integrated design – is currently ongoing, addressing the challenge of integrating the geotechnical discipline in the design process. The project aims to develop foundation and soil models to be used in dynamic time-domain analyses of offshore wind turbine structures. A library of models has been developed for representation of the most common foundation types. The models can be applied to different ground conditions by site-specific model input. To make the models applicable for practical usage, it has been important to balance the need for computational effectiveness against the need for accuracy. Studies so far indicate that the foundation models improve the accuracy in the integrated analyses.publishedVersionContent from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Lt

    REDWIN – REDucing cost in offshore WINd by integrated structural and geotechnical design

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    The cost of offshore wind energy production has to be reduced continuously to improve its competitiveness compared to other energy sources. To contribute to this goal, a 4- year research project REDWIN – REDucing cost of offshore WINd by structural and geotechnical integrated design – is currently ongoing, addressing the challenge of integrating the geotechnical discipline in the design process. The project aims to develop foundation and soil models to be used in dynamic time-domain analyses of offshore wind turbine structures. A library of models has been developed for representation of the most common foundation types. The models can be applied to different ground conditions by site-specific model input. To make the models applicable for practical usage, it has been important to balance the need for computational effectiveness against the need for accuracy. Studies so far indicate that the foundation models improve the accuracy in the integrated analyses

    A multi-species evaluation of digital wildlife monitoring using the Sigfox IoT network

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    Bio-telemetry from small tags attached to animals is one of the principal methods for studying the ecology and behaviour of wildlife. The field has constantly evolved over the last 80 years as technological improvement enabled a diversity of sensors to be integrated into the tags (e.g., GPS, accelerometers, etc.). However, retrieving data from tags on free-ranging animals remains a challenge since satellite and GSM networks are relatively expensive and or power hungry. Recently a new class of low-power communication networks have been developed and deployed worldwide to connect the internet of things (IoT). Here, we evaluated one of these, the Sigfox IoT network, for the potential as a real-time multi-sensor data retrieval and tag commanding system for studying fauna across a diversity of species and ecosystems. We tracked 312 individuals across 30 species (from 25 g bats to 3 t elephants) with seven different device concepts, resulting in more than 177,742 successful transmissions. We found a maximum line of sight communication distance of 280 km (on a flying cape vulture [Gyps coprotheres]), which sets a new documented record for animal-borne digital data transmission using terrestrial infrastructure. The average transmission success rate amounted to 68.3% (SD 22.1) on flying species and 54.1% (SD 27.4) on terrestrial species. In addition to GPS data, we also collected and transmitted data products from accelerometers, barometers, and thermometers. Further, we assessed the performance of Sigfox Atlas Native, a low-power method for positional estimates based on radio signal strengths and found a median accuracy of 12.89 km (MAD 5.17) on animals. We found that robust real-time communication (median message delay of 1.49 s), the extremely small size of the tags (starting at 1.28 g without GPS), and the low power demands (as low as 5.8 µAh per transmitted byte) unlock new possibilities for ecological data collection and global animal observation.ISSN:2050-338
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