130,547 research outputs found
MeSH term explosion and author rank improve expert recommendations
Full text linkInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
Full text linkBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Scholarly Communication and Publishing Lunch and Learn Talk #11: The ULS Open Access Author Fee Fund
No full textAt the May 2014 talk, you will learn about the ULS Open Access Author Fee Fund--what it is, why we do it, how it works, and how the program is going so far
Doppler-Kohärenz-Abbildung von Ionendynamiken in den Plasmaexperimenten VINETA.II und ASDEX Upgrade
Full text linkIn magnetically confining plasma experiments, measurement of ion dynamics is of great importance to study the plasma behaviour in magnetic fields such as the exhaust particle flows in the divertor areas. The plasma exhaust heat flux in a future nuclear power plant is estimated to be too high for the proposed wall materials. This is due to the relatively small areas, where the exhaust plasma interacts with the wall, that result in high local heat loads in these small interaction areas. A solution for the exhaust problem for future high power plasma experiments is one of the major challenges for magnetic confinement fusion as an energy source. High quality experimental measurements are necessary to improve understanding of the scrape-off-layer (SOL) and divertor physics as well as to validate simulation results of edge codes such as e.g. EMC3-Eirene or SOLPS. Understanding the plasma exhaust and edge behaviour is crucial to make correct assumptions about a future, large-sized power plant. This thesis is concerned with the development of a diagnostic measuring impurity ion flows in the SOL and divertor as well as basic physical understanding of these measured flows. Doppler coherence imaging spectroscopy (CIS) is a relatively new technique for the observation of plasma bulk ion dynamics in magnetically confined plasma experiments. It is a passive optical diagnostic that measures 2D images of the line-integrated ion flow and temperature, thus having the potential to vastly increase our knowledge about the SOL physics. Since its invention, the Doppler CIS has been further developed and tested in several plasma experiments such as DIII-D, H-1NF, MAGPIE and MAST. The Doppler CIS has the advantage of a relatively simple hardware set-up with high entendue, providing high flow sensitivity and an order of magnitude more data at higher signal-to-noise than traditional systems. However, absolute flow calibration has proven to be difficult for many impurity ion species present in the divertor of larger plasma experiments. This is due to lack of nearby calibration lines, ambient temperature changes of the diagnostic hardware as well as the difficulty to create a calibration light source equivalent to the plasma. The diagnostic was used successfully for first Doppler CIS ion flow measurements in the small, low-temperature linear plasma experiment VINETA.II and the medium-sized tokamak ASDEX Upgrade (AUG). The main physics objective of these studies is the research of ion dynamics in the two experiments. In VINETA.II, drifts due to electric fields were found to dominate ion dynamics. In the SOL and divertor of AUG, though there is a complex interplay of several drive mechanisms influencing the impurity ion dynamics, flows were found to be rather stable in the set of discharges where the Doppler CIS was employed. The physical background of SOL and divertor flows is reviewed in detail. This work focuses on the general characteristics of impurity ion flows in the poloidal field divertor and on bulk plasma ion flow in VINETA.II. Doppler CIS measurements from both experiments are presented: C-III, He-II and D-I in AUG as well as Ar II flows in VINETA.II. A flexible diagnostic set-up was designed to directly calibrate each flow measurement immediately before and after an investigated plasma discharge, making absolutely calibrated flow measurements possible without the use of active or passive temperature control. In AUG, they show a change of flow sign between the two divertor legs that is expected due to magnetic topology. The measured flow speeds are in the range of several kilometers per second and are mainly parallel to the magnetic field lines.In Plasmaexperimenten mit magnetischem Einschluss ist die Messung von Ionen-Dynamiken essentiell um das Plasmaverhalten in Magnetfeldern zu verstehen. Insbesondere ist das ausströmende Plasma im (magnetisch offenen) Rand- und Divertorbereich vom großen Interesse, da in einem zukünftigen Kernfusionsreaktor die Wärmeflüsse auf die Wand als sehr groß eingeschätzt werden. Dies liegt daran, dass die Regionen, in denen das ausströmende Plasma auf die Wand trifft, räumlich klein sind und die lokale Wärmebelastung pro Fläche dadurch sehr groß wird. Die Lösung dieses Problems ist eine Voraussetzung, um die Kernfusion mit magnetisch eingeschlossenen Hochtemperaturplasmen nutzen zu können. Genaue Messungen werden benötigt, um das Verständnis des Plasmas im magnetisch offenen Randbereich und am Divertor zu verbessern, sowie um entsprechende Computersimulationen von Codes wie EMC3-Eirene oder SOLPS zu verifizieren. Das Verstehen und korrekte Beschreiben des Randschichtplasmas ist entscheidend, um die richtige Auslegung für das ausströmende Plasma bei zukünftigen, großen Hochtemperatur-Plasmaanlagen treffen zu können. Diese Arbeit beschäftigt sich mit der Entwicklung einer spektralen Diagnostik, die die Verunreinigungsflüsse im offenen Randbereich messen kann. Der Fluss von Wand-Verunreinigungen spielt eine wichtige Rolle für den Betrieb eines Plasmaexperimentes und lässt auch Rückschlüsse auf die ausströmenden Ionenflüsse des Hauptplasmas zu. Das Doppler-Kohärenz-Abbildungsverfahren ist eine relativ neue Methode zur Messung von Ionendynamiken in Plasmaexperimenten. Optisch passiv nimmt sie Bilder aus dem sichtbaren Bereich vom Plasma auf und kann den linienintegrierten Ionenfluss und die Ionentemperatur in ihnen sichtbar machen. Beide Parameter können bisher vor allem nur lokal in der Randschicht gemessen werden. Die Doppler-Kohärenz-Abbildungs-Diagnostik (KAD) hat deshalb das Potential, unser Verständnis dieser beiden Parameter für die Randschichtphysik deutlich zu vergrößern. Seit ihrer Erfindung wurde die Doppler KAD weiterentwickelt und in mehreren Plasmaexperimenten (DIII-D, WEGA, H-1NF, MAGPIE, MAST...) eingesetzt. Sie zeichnet sich durch einen relativ simplen Aufbau mit großem Entendue aus und liefert ca. eine Größenordnung mehr Daten mit höherem Signal-zu-Rausch Verhältnis als traditionelle spektroskopische Systeme. Allerdings ist die Kalibration der Flussmessung für viele spektrale Plasmalinien sehr schwierig. Dies liegt am teilweisen Fehlen von geeigneten Kalibrationslinien, Temperaturveränderungen der Diagnostik-Kristalle und an dem Umstand, dass die Diagnostik nicht in der Objektebene innerhalb des Torus kalibriert werden kann. Erfolgreiche Messungen mit der Diagnostik wurden am linearen Niedertemperatur-Plasmaexperiment VINETA.II und dem Tokamak ASDEX Upgrade (AUG) durchgeführt. Das physikalische Ziel dieser Messungen war die Untersuchung der Ionendynamiken in beiden Experimenten. In VINETA.II wurden azimutale Plasma Driften aufgrund von einem radialen elektrischen Feld gemessen. Im offenen Randschichtbereich und am Divertor von AUG gibt es ein komplexeres Zusammenwirken von verschiedenen Flussursachen. Trotzdem wurden in den mit der Doppler KAD untersuchten Entladungen für verschiedene Verunreinigungsspezies relativ konstante Flüsse beobachtet. Die verschiedenen physikalischen Ursachen von Ionenflüssen werden im Detail für poloidale Feld-Divertoren (eingesetzt in AUG) sowie für das Hauptplasma in VINETA.II beschrieben. Messungen aus beiden Experimenten werden präsentiert: C III, He II und D-α in AUG sowie für Ar II Flüsse in VINETA.II. Ein flexibler Diagnostik-Aufbau wurde realisiert, um direkt vor und nach jeder Plasmaentladung kalibrieren zu können. Dies ermöglichte absolut kalibrierte Flussmessungen ohne die Nutzung von aktiver oder passiver Temperaturkontrolle. In AUG wurde ein Wechsel der Flussrichtung (vom Beobachter weg bzw. zum Beobachter hin) zwischen den beiden Divertorbeinen beobachtet. Dies wird aufgrund der Magnetfeldtopologie erwartet. Die gemessenen Flussgeschwindigkeiten liegen im Bereich von mehreren Kilometern pro Sekunde und sind hauptsächlich parallel zu den Magnetfeldlinien.EC/H2020/633053/Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortiu
The R&D Tax Incentives
No full textThis article sets out some background information and reflections of the author on the R&D tax incentive schemes included in the Common Corporate Tax Base (CCTB) Proposal. In particular the author analyzes the stimulus to private R&D through ad hoc tax incentives included in the CCTB Proposal and dives into the actual provisions included in the Proposal highlighting the most relevant issues connected with their design and interpretation. Moreover, the author explores the interaction between the CCTB Proposal and the granting by Member States of domestic R&D tax incentives
Morphologic and functional correlates of synaptic pathology in the cathepsin D knockout mouse model of congenital neuronal ceroid lipofuscinosis
Full text linkMutations in the cathepsin D (CTSD) gene cause an aggressive neurodegenerative disease (congenital neuronal ceroid lipofuscinosis) that leads to early death. Recent evidence suggests that presynaptic abnormalities play a major role in the pathogenesis of CTSD deficiencies. To identify the early events that lead to synaptic alterations, we investigated synaptic ultrastructure and function in presymptomatic CTSD knockout (Ctsd) mice. Electron microscopy revealed that there were significantly greater numbers of readily releasable synaptic vesicles present in Ctsd mice than in wild-type control mice as early as postnatal day 16. The size of this synaptic vesicle pool continued to increase with disease progression in the hippocampus and thalamus of the Ctsd mice. Electrophysiology revealed a markedly decreased frequency of miniature excitatory postsynaptic currents (mEPSCs) with no effect on paired-pulse modulation of the evoked excitatory post synaptic potentials in the hippocampus of Ctsd mice. The reduced mEPSCs frequency was observed before the appearance of epilepsy or any morphologic sign of synaptic degeneration. Taken together, these data indicate that CTSD is required for normal synaptic function and that a failure in synaptic trafficking or recycling may bean early and important pathologic mechanism in Ctsd mice; these presynaptic abnormalities may initiate synaptic degeneration in advance of subsequent neuronal loss
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