131 research outputs found

    An Adaptive Flow-Aware Packet Scheduling Algorithm for Multipath Tunnelling

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    This paper proposes AFMT, a packet scheduling algorithm to achieve adaptive flow-aware multipath tunnelling. AFMT has two unique properties. Firstly, it implements robust adaptive traffic splitting for the subtunnels. Secondly, it detects and schedules bursts of packets cohesively, a scheme that already enabled traffic splitting for load balancing with little to no packet reordering. Several NS-3 experiments over different network topologies show that AFMT successfully deals with changing path characteristics due to background traffic while increasing throughput and reliability.Comment: submitted and accepted on IEEE LCN 2019, 4 pages, 5 figure

    VUV photon induced fluorescence study of SF5CF3

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    The interaction of SF5_5CF3_3 with vacuum-UV radiation has been investigated by photon induced fluorescence spectroscopy. Total fluorescence yield and dispersed fluorescence spectra of SF5_5CF3_3 were recorded in the 200-1000 nm fluorescence window. In all cases, the fluorescence spectra resemble those of CF3_3X (X=H, F, Cl, and Br) molecules. At photon energies below 20 eV, the emission is attributed to the excited CF3_3 and CF2_2 fragments. The threshold for the CF3_3 emission is 10.2 ± 0.2 eV, giving an upper-limit estimate for the SF5_5-CF3_3 bond dissociation energy of 3.9 ± 0.3 eV. The excitation functions of the CF3 and CF2 emissions were measured in the photon energy range 13.6 – 27.0 eV. The resonant structures observed in SF5_5CF3_3 are attributed to electronic transitions from valence to Rydberg orbitals, following similar assignments in CF3_3X molecules. The photoabsorption spectrum of SF5_5CF3_3 shows features at the same energies, indicating a strong contribution from Rydberg excitations

    Cy Twombly. Bild, Text, Paratext

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    Die Bildwerke des US-amerikanischen KĂŒnstlers Cy Twombly (1928–2011) gelten als hermetisch und schwer zugĂ€nglich. Bleistiftgekritzel, Farbballungen, taumelnde Linien, einander ĂŒberlagernde Farbschichten und Einschreibungen, geometrische Figuren, Zahlen, Zahlenreihen, Wörter, Zitatfragmente und rĂ€tselhafte Bildtitel stellen Forscher wie Betrachter vor ganz besondere Herausforderungen. GemĂ€ĂŸ der interdisziplinĂ€r-transkulturellen Forschungsmethode des Internationalen Kollegs Morphomata an der UniversitĂ€t zu Köln versammelte im Juni 2012 ein Kongress neben Kunsthistorikern auch namhafte Fachleute aus den Bereichen Ägyptologie, ArchĂ€ologie, Germanistik, GrĂ€zistik, Anglistik, Japanologie und Romanistik, d.h. all jenen Fachgebieten und Kulturkreisen, die eine Inspirationsquelle fĂŒr das OEuvre Cy Twomblys darstellten. Befragen diese den Bezug zwischen Werktitel, Werk und eingeschriebenen Zitaten, so legen fĂŒhrende Vertreter der Twomblyforschung den Fokus auf Bildsprache und Schriftbildlichkeit bei Cy Twombly. Durch umfassende Deutungen berĂŒhmter Einzelwerke und Werkgruppen in sĂ€mtlichen von Twombly angewandten kĂŒnstlerischen Medien erschließt der Band in einem fĂ€cherĂŒbergreifenden Blick einen Zugang zur assoziativ-referentiellen Bildsprache Cy Twomblys

    Cy Twombly. Image, Text, Paratext

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    The artworks of the US artist Cy Twombly (1928–2011) are considered to be hermetic and inaccessible. Pencil scribblings, explosions of paint, tumbling lines, overlapping layers of color, and inscriptions, geometrical figures, numerals, rows of numbers, words, fragments of quotations, and enigmatic work-titles present very special challenges to both researchers and viewers. In the interdisciplinary and transcultural research method of the Morphomata International Center for Advanced Studies at the University of Cologne, a conference was held in June 2012 that brought art historians together with renowned scholars of Egyptology, Archaeology, German, Greek, English, Japanese, and the Romance languages, i.e. all the fields and cultural spheres that were a source of inspiration for the Ɠuvre of Cy Twombly. While these scholars inquire into the relation between title, work, and inscribed quotations, leading representatives of research on Twombly focus on the visual language and scriptural-imagistic quality of Cy Twombly’s work. Through comprehensive interpretations of famous single works and groups in all the artistic media employed by Twombly, the volume’s cross-disciplinary view opens up a route into the associative-referential visual language of Cy Twombly

    Shower development of particles with momenta from 15 GeV to 150 GeV in the CALICE scintillator-tungsten hadronic calorimeter

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    We present a study of showers initiated by electrons, pions, kaons, and protons with momenta from 15 GeV to 150 GeV in the highly granular CALICE scintillator-tungsten analogue hadronic calorimeter. The data were recorded at the CERN Super Proton Synchrotron in 2011. The analysis includes measurements of the calorimeter response to each particle type as well as measurements of the energy resolution and studies of the longitudinal and radial shower development for selected particles. The results are compared to Geant4 simulations (version 9.6.p02). In the study of the energy resolution we include previously published data with beam momenta from 1 GeV to 10 GeV recorded at the CERN Proton Synchrotron in 2010.Comment: 35 pages, 21 figures, 8 table

    Cortico-muscular coherence is reduced acutely post-stroke and increases bilaterally during motor recovery: a pilot study

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    Motor recovery following stroke is believed to necessitate alteration in functional connectivity between cortex and muscle. Cortico-muscular coherence has been proposed as a potential biomarker for post-stroke motor deficits, enabling a quantification of recovery, as well as potentially indicating the regions of cortex involved in recovery of function. We recorded simultaneous EEG and EMG during wrist extension from healthy participants and patients following ischaemic stroke, evaluating function at three time points post-stroke. EEG–EMG coherence increased over time, as wrist mobility recovered clinically, and by the final evaluation, coherence was higher in the patient group than in the healthy controls. Moreover, the cortical distribution differed between the groups, with coherence involving larger and more bilaterally scattered areas of cortex in the patients than in the healthy participants. The findings suggest that EEG–EMG coherence has the potential to serve as a biomarker for motor recovery and to provide information about the cortical regions that should be targeted in rehabilitation therapies based on real-time EEG

    Randomized Controlled Trial of Interval-Compressed Chemotherapy for the Treatment of Localized Ewing Sarcoma: A Report From the Children's Oncology Group

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    Chemotherapy with alternating vincristine-doxorubicin-cyclophosphamide and ifosfamide-etoposide cycles and primary tumor treatment with surgery and/or radiation therapy constitute the usual approach to localized Ewing sarcoma in North America. We tested whether chemotherapy intensification through interval compression could improve outcome

    The Time Structure of Hadronic Showers in highly granular Calorimeters with Tungsten and Steel Absorbers

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    The intrinsic time structure of hadronic showers influences the timing capability and the required integration time of hadronic calorimeters in particle physics experiments, and depends on the active medium and on the absorber of the calorimeter. With the CALICE T3B experiment, a setup of 15 small plastic scintillator tiles read out with Silicon Photomultipliers, the time structure of showers is measured on a statistical basis with high spatial and temporal resolution in sampling calorimeters with tungsten and steel absorbers. The results are compared to GEANT4 (version 9.4 patch 03) simulations with different hadronic physics models. These comparisons demonstrate the importance of using high precision treatment of low-energy neutrons for tungsten absorbers, while an overall good agreement between data and simulations for all considered models is observed for steel.Comment: 24 pages including author list, 9 figures, published in JINS

    Perceptual impairment and psychomotor control in virtual laparoscopic surgery

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    Background: It is recognised that one of the major difficulties in performing laparoscopic surgery is the translation of two-dimensional video image information to a three-dimensional working area. However, research has tended to ignore the gaze and eye-hand coordination strategies employed by laparoscopic surgeons as they attempt to overcome these perceptual constraints. This study sought to examine if measures related to tool movements, gaze strategy, and eye-hand coordination (the quiet eye) differentiate between experienced and novice operators performing a two-handed manoeuvres task on a virtual reality laparoscopic surgical simulator (LAP Mentorℱ). Methods: Twenty-five right-handed surgeons were categorised as being either experienced (having led more than 60 laparoscopic procedures) or novice (having performed fewer than 10 procedures) operators. The 10 experienced and 15 novice surgeons completed the "two-hand manoeuvres" task from the LAP Mentor basic skills learning environment while wearing a gaze registration system. Performance, movement, gaze, and eye-hand coordination parameters were recorded and compared between groups. Results: The experienced surgeons completed the task significantly more quickly than the novices, used significantly fewer movements, and displayed shorter tool paths. Gaze analyses revealed that experienced surgeons spent significantly more time fixating the target locations than novices, who split their time between focusing on the targets and tracking the tools. A more detailed analysis of a difficult subcomponent of the task revealed that experienced operators used a significantly longer aiming fixation (the quiet eye period) to guide precision grasping movements and hence needed fewer grasp attempts. Conclusion: The findings of the study provide further support for the utility of examining strategic gaze behaviour and eye-hand coordination measures to help further our understanding of how experienced surgeons attempt to overcome the perceptual difficulties inherent in the laparoscopic environment. © 2011 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

    Reduced Amygdala and Ventral Striatal Activity to Happy Faces in PTSD Is Associated with Emotional Numbing

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    There has been a growing recognition of the importance of reward processing in PTSD, yet little is known of the underlying neural networks. This study tested the predictions that (1) individuals with PTSD would display reduced responses to happy facial expressions in ventral striatal reward networks, and (2) that this reduction would be associated with emotional numbing symptoms. 23 treatment-seeking patients with Posttraumatic Stress Disorder were recruited from the treatment clinic at the Centre for Traumatic Stress Studies, Westmead Hospital, and 20 trauma-exposed controls were recruited from a community sample. We examined functional magnetic resonance imaging responses during the presentation of happy and neutral facial expressions in a passive viewing task. PTSD participants rated happy facial expression as less intense than trauma-exposed controls. Relative to controls, PTSD participants revealed lower activation to happy (-neutral) faces in ventral striatum and and a trend for reduced activation in left amygdala. A significant negative correlation was found between emotional numbing symptoms in PTSD and right ventral striatal regions after controlling for depression, anxiety and PTSD severity. This study provides initial evidence that individuals with PTSD have lower reactivity to happy facial expressions, and that lower activation in ventral striatal-limbic reward networks may be associated with symptoms of emotional numbing
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