764 research outputs found

    The specialized thoracic skeletomuscular system of the myrmecophile Claviger testaceus (Pselaphinae, Staphylinidae, Coleoptera)

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    External and internal structures of the thorax of the myrmecophile beetle Claviger testaceus (Clavigeritae, Pselaphinae) were examined and documented with state-of-the-art visualization techniques. Following a general trend in the omaliine lineage (Staphylinidae), the skeletal elements of the pro- and pterothorax in Claviger reach a maximum degree of compactness, with largely reduced inter- and intrasegmental sutures and skeletal elements linked with the flight apparatus. The musculature, especially metathoracic direct and indirect flight muscles, also shows a high degree of reduction. Two forms of wings were found among individuals of C. testaceus, both non-functional and representing an advanced stage of reduction. However, that wing vestiges are still present and the metanotum, only slightly reduced, suggests that loss of flight in this species is likely the result of a young evolutionary process. Several structures are linked with myrmecophilous habits: small body size facilitates transportation of beetles by ant workers and makes it easier to move inside nest tunnels; the remarkably compact body and mechanically robust appendages make the beetles less vulnerable to attacks by ant mandibles; the improved elytral interlocking mechanism and unusually expanded epipleura enhance the protection of vulnerable dorsal parts of the pterothorax and anterior abdomen; and glands associated with trichomes on the posterolateral elytral angle produce secretions attractive for ants. Various modifications of the thorax and anterior abdomen lead to an optimization of intimate associations with ants. The morphological syndrome enabling these beetles to cope with life in ant colonies evolved in several steps. This is suggested by an increasing solidification of the thoracic skeleton in related non-myrmecophilous groups and also by less modified related clavigerites;for instance, ant-associated tropical species are still able to fly.Introduction Materials and methods - Studied species - Light microscopy - Micro-computed tomography (μCT) - Scanning electron microscopy (SEM) - Terminology Results - Prothorax - Pterothorax - Anterior abdominal segments Discussion - Phylogenetic background - Musculature - Elytral locking system and flightlessness - Myrmecophilous habits Conclusion

    VegMachine.net. Online land cover analysis for the rangelands

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    VegMachine.net is an online land cover monitoring tool unded by the Fitzroy Basin Association (FBA). The tool focuses primarily on Queensland, but has functionality for much of Australia’s rangelands. The website went live in July 2016 and recently logged the 1000th user session. Users can view seven different seasonal time series of cover products across the landscape and interactively interrogate and graph ground cover change in six different on-the-fly and email delivered reports. Results can then be exported for use in other software. To date, users have generated over 400 VegMachine® FORAGE ground cover reports which provide paddock-by-paddock, landtype-by-landtype analysis of ground cover change from 1990 to the present. Detailed help is available in multiple formats, including website popups and a dedicated YouTube channel. The web application was designed for two main user groups; technically equipped RD&E personnel including those servicing land manager clients, and a subset of the grazier community willing to operate the service themselves. Initial rollout of the application focused primarily on training events for government agency, private consultancy and natural resource management (NRM) staff in regional Queensland. These users form the core of the current user base. In this paper, we outline the development of VegMachine.net. We demonstrate the primary functionality of the website, provide an overview of user experience including a case study and discuss major learnings and future directions

    VegMachine.net. online land cover analysis for the Australian rangelands

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    This paper documents the development and use of the VegMachine.net land cover monitoring tool. From 2002 to 2015, VegMachine® software was used by government agencies, natural resource management (NRM) groups and individual pastoralists in northern Australia to assess and benchmark vegetation cover levels. In 2016 the VegMachine.net website was launched to build a wider user base and assure service continuity. Users can now graph historical (1990-) cover on one or more user defined areas of interest (AOI), produce comprehensive paddock-by-paddock property monitoring reports, and view a range of land cover raster images through the website map panel. In its first 32 months of operation 913 users logged 1604 sessions on the website and more than 1000 of the website's most comprehensive monitoring reports were distributed to users. Levels of use varied 26% of users (n = 237) have used the website more than once, and within this group a smaller set of regular users (n = 36) have used the site more than five times, in many cases to provide analyses to multiple clients. We outline four case studies that document the significant impact VegMachine.net has had on users including graziers, government agencies, NRM groups and researchers. We also discuss some possible paths forward that could widen the user base and improve retention of first time users. © 2019 The State of Queensland (through the Department of Agriculture and Fisheries) 2019 Open Access

    Detector for imaging of explosions: present status and future prospects with higher energy X-rays

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    The detector for imaging of explosions (DIMEX) is in operation at the synchrotron radiation (SR) beam-line at VEPP-3 electron ring at Budker INP since 2002. DIMEX is based on one-coordinate gas ionization chamber filled with Xe-CO2(3:1) mixture at 7atm, and active Frisch-grid made of Gas Electron Multiplier (GEM). The detector has spatial resolution of ~0.2mm and dynamic range of ~100 that allows to realize the precision of signal measurement at a percent level. The frame rate can be tuned up to 8 MHz (125 ns per image) and up to 32 images can be stored in one shot. At present DIMEX is used with the X-ray beam from 2T wiggler that has ~20 keV average energy. Future possibility to install similar detector at the SR beam-line at VEPP-4 electron ring is discussed.Comment: 14 pages, 15 figures. Submitted to JINS

    Wonderfully weird: the head anatomy of the armadillo ant, Tatuidris tatusia (Hymenoptera: Formicidae: Agroecomyrmecinae), with evolutionary implications

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    Tatuidris tatusia Brown & Kempf, 1968, the armadillo ant, is a morphologically unique species found in low to high elevation forests in regions of Central and South America. It is one of only two extant representatives of the subfamily Agroecomyrmecinae, and very little is known about the biology of these ants, which are almost exclusively collected from leaf litter and have rarely been seen alive. Here, we illuminate the functional morphology and evolution of this species via detailed anatomical documentation of their exceptionally modified head. We describe and illustrate the skeletomuscular system, digestive tract, and cephalic glands based on high-resolution micro-computed tomography scan data. We hypothesize that the modifications which produce the unusual “shield-like” head shape are the result of complex optimizations for mandibular power, physical protection, and balance. The most conspicuous cephalic features are the broadening of the frontal region and foreshortening of the postgenal region. The former characteristic is likely also associated with the lateral position of the antennal scrobe, the inverted antennal articulation, and the broad attachment surface for the mandibular adductor muscles. This head geometry also comes with a degree of internal restructuring of the tentorium and the antennal musculature, which have a unique configuration among ants studied so far. The mandibular blades, and their articulations and muscles, are highly distinctive compared with previously evaluated species. Using a 3D-printed model, we were able to hypothesize their entire range of motion as the mandibles fit tightly into the oral foramen. Finally, we compare T. tatusia across other related subfamilies and discuss the evolution of the Agroecomyrmecinae and other species-poor and phylogenetically isolated “relictual” lineages.journal articl

    Electrically-Driven Light Emitter in Tailor-Made Photonic Crystal Cavity

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    Single-photon detection and cryogenic reconfigurability in Lithium Niobate nanophotonic circuits

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    Lithium-Niobate-On-Insulator (LNOI) is emerging as a promising platform for integrated quantum photonic technologies because of its high second-order nonlinearity and compact waveguide footprint. Importantly, LNOI allows for creating electro-optically reconfigurable circuits, which can be efficiently operated at cryogenic temperature. Their integration with superconducting nanowire single-photon detectors (SNSPDs) paves the way for realizing scalable photonic devices for active manipulation and detection of quantum states of light. Here we report the first demonstration of these two key components integrated in a low loss (0.2 dB/cm) LNOI waveguide network. As an experimental showcase of our technology, we demonstrate the combined operation of an electrically tunable Mach-Zehnder interferometer and two waveguide-integrated SNSPDs at its outputs. We show static reconfigurability of our system with a bias-drift-free operation over a time of 12 hours, as well as high-speed modulation at a frequency up to 1 GHz. Our results provide blueprints for implementing complex quantum photonic devices on the LNOI platform
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