1,822 research outputs found

    The Soviet Union: The Incomplete Superpower

    Get PDF

    GridScore:a tool for accurate, cross-platform phenotypic data collection and visualization

    Get PDF
    Background: Plant breeding and crop research rely on experimental phenotyping trials. These trials generate data for large numbers of traits and plant varieties that needs to be captured efficiently and accurately to support further research and downstream analysis. Traditionally scored by hand, phenotypic data is nowadays collected using spreadsheets or specialized apps. While many solutions exist, which increase efficiency and reduce errors, none offer the same familiarity as printed field plans which have been used for decades and offer an intuitive overview over the trial setup, previously recorded data and plots still requiring scoring.Results: We introduce GridScore which utilizes cutting-edge web technologies to reproduce the familiarity of printed field plans while enhancing the phenotypic data collection process by adding advanced features like georeferencing, image tagging and speech recognition. GridScore is a cross-platform open-source plant phenotyping app that combines barcode-based systems with a guided data collection approach while offering a top-down view onto the data collected in a field layout. GridScore is compared to existing tools across a wide spectrum of criteria including support for barcodes, multiple platforms, and visualizations.Conclusion: Compared to its competition, GridScore shows strong performance across the board offering a complete manual phenotyping experience.</p

    Measurement of the Mass and Stellar Population Distribution in M82 with the LBT

    Full text link
    We present a K-band spectroscopic study of the stellar and gas kinematics, mass distribution, and stellar populations of the archetypical starburst galaxy M82. Our results are based on a single spectrum at a position angle of 67.5 degrees through the K-band nucleus. We used the CO stellar absorption band head at 2.29 {\mu}m (CO_2.29) to measure the rotation curve out to nearly 4 kpc radius on both the eastern and western sides of the galaxy. Our data show that the rotation curve is flat from 1 - 4 kpc. This stands in sharp contrast to some previous studies, which have interpreted H I and CO emission-line position-velocity diagrams as evidence for a declining rotation curve. The kinematics of the Br\gamma, H_2, and He I emission lines are consistent with, although characterized by slightly higher velocities than, the stellar kinematics. We derived M82's mass distribution from our stellar kinematic measurements and estimate its total dynamical mass is ~10^10 Msun. We measured the equivalent width of CO_2.29 (W_2.29) as a function of distance from the center of the galaxy to investigate the spatial extent of the red supergiant (RSG) population. The variation in W_2.29 with radius clearly shows that RSGs dominate the light inside 500 pc radius. M82's superwind is likely launched from this region, where we estimate the enclosed mass is <= 2 x 10^9 Msun.Comment: 6 pages, 6 figures. Submitted to ApJ. For a brief video explaining the key result of this paper, see http://www.youtube.com/user/OSUAstronom

    Tribological mechanisms of slurry abrasive wear

    Get PDF
    Abrasive wear mechanisms—including two-body and three-body abrasion—dominate the performance and lifespan of tribological systems in many engineering fields, even of those operating in lubricated conditions. Bearing steel (100Cr6) pins and discs in a flat-on-flat contact were utilized in experiments together with 5 and 13 µm Al2_{2}O3_{3}-based slurries as interfacial media to shed light on the acting mechanisms. The results indicate that a speed-induced hydrodynamic effect occurred and significantly altered the systems’ frictional behavior in tests that were performed using the 5 µm slurry. Further experiments revealed that a speed-dependent hydrodynamic effect can lead to a 14% increase in film thickness and a decrease in friction of around 2/3, accompanied by a transition from two-body abrasion to three-body abrasion and a change in wear mechanism from microcutting and microploughing to fatigue wear. Surprisingly, no correlation could be found between the total amount of wear and the operating state of the system during the experiment; however, the wear distribution over pin and disc was observed to change significantly. This paper studies the influence of the hydrodynamic effect on the tribological mechanism of lubricated abrasive wear and also highlights the importance to not only consider a tribological systems’ global amount of wear

    Endovascular treatment of cervical myelopathy from brachiocephalic venous stenosis.

    Get PDF
    Central venous stenosis is a rare cause of neurologic pathology. Here we present a case of brachiocephalic vein stenosis causing cervical myelopathy through venous engorgement. Our patient was a 51-y/o male who presented with ambulatory dysfunction so he was evaluated for cervical myelopathy. Imaging revealed cord compression from venous engorgement and brachiocephalic vein stenosis. He was treated with angioplasty and vessel stenting which significantly improved flow on postintervention imaging. In conclusion, preoperative vascular imaging should be considered in myelopathic patients as it can detect this rare but dangerous etiology

    Application of system dynamics for holistic product-service system development

    Get PDF
    In order to develop Product Service Systems (PSS), a holistic view on the system and a coequal development of service and product parts is necessary. Particularly for the beginning of the development of PSS, existing approaches show lacks and start with vague defined initial phases. This leads to inadequate methodological support for the consistent design of the overall system and simultaneous elaboration of the requirements down to the parameters of individual components. Therefore, a procedure is required that completely maps the PSS and enables detailed development for relevant individual areas, taking into account existing constraints. At the beginning of the development a model is necessary, which first defines the system boundaries of the PSS and maps the performance and control flows of the system. In addition, the integration of further actors into the PSS must be made possible. This paper presents an approach that uses System Dynamics (SD) to design a PSS. With this approach, the representation of the system is initially possible at a high level of abstraction, whereby the representation can be further refined and detailed. Parallel to this, a preliminary design for planning and controlling media flows can be carried out from the first system representation and further detailed parallel to the system representation. An essential advantage is that the detailing can also only be carried out for individual areas, which can be displayed in sub-models, but can also be reintegrated into the overall representation. The sub-models can be implemented function-specifically on the basis of resources and competencies of individual actors. For system-relevant areas, planning and design can be concretized in the sub-models (which can be realized by products as well as services) down to the lowest hierarchy level. This can take place up to the definition of individual physical component parameters and has thus up to the phase of the elaboration effects on the development of the parts. In return, the effects of changes in system-relevant parameters on the overall system can also be examined. For the PSS, a model is built in which system-determining functions and principles are represented and developed. The model is constructed in such a way that non-system-determining functions and principles are defined as variables or black boxes. Requirements and parameters are derived from this system development. These are used for the further development steps in the development process. Depending on whether it concerns system-relevant areas or not, the entry into the development process takes place later in the elaboration phase (e.g. in the area of detailed design) or partly earlier in the concept phase (e.g. function development). It is also possible to enter an early phase in the development process of the individual parts, accompanied by already defined functions, sub-functions or parameters that must not be changed in the course of development. With this approach a holistic development of the system with all product and service parts as well as their connections and dependencies is possible

    Die tribologischen Eigenschaften Silicium-basierter Keramiken in Isooctan unter Berücksichtigung der Umgebungsatmosphäre

    Get PDF
    Im Rahmen dieser Arbeit wurden die tribologischen Eigenschaften von selbstgepaartem Siliciumcarbid (SSiC) und Siliciumnitrid (Si₃N₄) unter dem Einfluss verschiedener Atmosphären (feuchte Luft, trockene Luft und trockener Stickstoff) charakterisiert, wobei die Wirkflächen der Keramiken zu jeder Zeit der Experimente durch Einsatz eines Tauchbades vollständig von Isooctan bedeckt waren. Die Versuche wurden allesamt in einer konformen Pellet Platte Konfiguration (Kontaktfläche nominell: ⌀ 9,5 mm) durchgeführt und es wurden eine reversierende Gleitbewegung mit Hublänge s = 5 mm, Hubfrequenzen von f = 2,5 bis 20 Hz und eine Normalkraft von Fₙ = 200 N gewählt. Die Ergebnisse zeigen, dass die chemischen Einflüsse aus der Umgebung trotz des Tauchbades signifikante Effekte auf das Reibungs- und Verschleißverhalten der beiden keramischen Werkstoffe haben. Im Falle des SSiC führte eine Atmosphäre aus feuchter Luft zu unruhigen Reibzahlverläufen mit kurzzeitigen Reibzahlüberhöhungen und generell höheren Reibwerten als in trockener Luft oder Stickstoffatmosphäre. Für Si₃N₄ äußerte sich der Einfluss überwiegend in veränderten Verschleißbeträgen und entstehenden Oberflächentopographien, hierbei führte Feuchtigkeit zur Bildung inselartiger, sauerstoffreicher Bereiche auf den Kontaktflächen. Durch den Einsatz kleinster Mengen einer grenzflächenaktiven Substanz (AOT) konnten Reib- und Verschleißverhalten beider Keramiken auf ein näherungsweise einheitliches Niveau gebracht werden. Zudem konnte nachgewiesen werden, dass für selbstgepaartes SSiC in Kombination mit Isooctan ein Übergang des Tribosystems in die flüssige Supraschmierfähigkeit mit Reibwerten von µ < 0,003 trotz reversierender Gleitbewegung eintritt. Erklärungsansätze in der Literatur für diesen Zustand in wässrigen Medien stützen sich häufig auf elektrochemische, Ionen-basierte Oberflächeneffekte, welche vor dem Hintergrund des verwendeten Isooctans nicht anwendbar sind. Die plausibelste Ursache für die verschwindend geringe Reibung ist ein oberflächentrennender Film aus Isooctan

    A Novel Role for Stat1 in Phagosome Acidification and Natural Host Resistance to Intracellular Infection by Leishmania major

    Get PDF
    Intracellular parasites of the genus Leishmania generate severe diseases in humans, which are associated with a failure of the infected host to induce a protective interferon γ (IFNγ)-mediated immune response. We tested the role of the JAK/STAT1 signaling pathway in Leishmania pathogenesis by utilizing knockout mice lacking the signal transducer and activator of transcription 1 (Stat1) and derived macrophages. Unexpectedly, infection of Stat1-deficient macrophages in vitro with promastigotes from Leishmania major and attenuated LPG1 knockout mutants (lpg−) specifically lacking lipophosphoglycan (LPG) resulted in a twofold increased intracellular growth, which was independent of IFNγ and associated with a substantial increase in phagosomal pH. Phagosomes in Stat1−/− macrophages showed normal maturation as judged by the accumulation of the lysosomal marker protein rab7, and provided normal vATPase activity, but were defective in the anion conductive pathway required for full vesicular acidification. Our results suggest a role of acidic pH in the control of intracellular Leishmania growth early during infection and identify for the first time an unexpected role of Stat1 in natural anti-microbial resistance independent from its function as IFNγ-induced signal transducer. This novel Stat1 function may have important implications to studies of other pathogens, as the acidic phagolysosomal pH plays an important role in antigen processing and the uncoating process of many viruses
    • …
    corecore