290 research outputs found

    Using Incomplete Information for Complete Weight Annotation of Road Networks -- Extended Version

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    We are witnessing increasing interests in the effective use of road networks. For example, to enable effective vehicle routing, weighted-graph models of transportation networks are used, where the weight of an edge captures some cost associated with traversing the edge, e.g., greenhouse gas (GHG) emissions or travel time. It is a precondition to using a graph model for routing that all edges have weights. Weights that capture travel times and GHG emissions can be extracted from GPS trajectory data collected from the network. However, GPS trajectory data typically lack the coverage needed to assign weights to all edges. This paper formulates and addresses the problem of annotating all edges in a road network with travel cost based weights from a set of trips in the network that cover only a small fraction of the edges, each with an associated ground-truth travel cost. A general framework is proposed to solve the problem. Specifically, the problem is modeled as a regression problem and solved by minimizing a judiciously designed objective function that takes into account the topology of the road network. In particular, the use of weighted PageRank values of edges is explored for assigning appropriate weights to all edges, and the property of directional adjacency of edges is also taken into account to assign weights. Empirical studies with weights capturing travel time and GHG emissions on two road networks (Skagen, Denmark, and North Jutland, Denmark) offer insight into the design properties of the proposed techniques and offer evidence that the techniques are effective.Comment: This is an extended version of "Using Incomplete Information for Complete Weight Annotation of Road Networks," which is accepted for publication in IEEE TKD

    Environmental Science Communication for a Young Audience: A Case Study on the #EarthOvershootDay Campaign on YouTube

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    Addressing global sustainability challenges such as climate change in democratic societies requires thorough political and societal debates. Science and environmental communication is needed to inform these debates. However, not all parts of society are equally reached by traditional science communication. In particular young people, especially without academic background, are often left out. The cooperation of science communicators with influencers on the video platform YouTube can be a way to convey scientific information and raise awareness for environmental issues with new young audiences. This case study looks at three videos from the campaign #EarthOvershootDay on YouTube by the WWF (World Wide Fund for Nature) Germany and the educational initiative MESH Collective. The focus of the analysis lies on the established success factors of communication through influencers—specifically authenticity, comprehensibility and storytelling—and how they play out in detail in the three exemplary videos. Besides the analysis of the videos, the study is corroborated by interviews with the producers and a comment analysis in order to include the perspective of the viewers. Our analysis confirms previous findings on science communication with influencers and illustrates the practical implementation of these findings. It shows that authenticity is a central aspect which is not disturbed through the presentation of scientific content. The storytelling approaches are tailored to the respective influencer and their style. The language and structure of the videos are simple and comprehensible, scientific arguments focus on selected aspects and are tied to examples from everyday life. The comments by the users support these findings with the majority of comments addressing the three aspects of our analysis being positive. However, evidence for an in-depth engagement with the scientific contents could not be found in the comments. The stated goal of the campaign to reach educationally disadvantaged young people was only reached to a limited degree according to the assessment of the producers. Additionally, the views of two of the three videos remained below the average for the respective channel. Taken together this indicates that cooperation with influencers might not be an “all-purpose tool” guaranteeing success for science communication

    Decentralized Identities for Self-sovereign End-users (DISSENS)

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    This paper describes a comprehensive architecture and reference implementation for privacy-preserving identity management that bucks the trend towards centralization present in contemporary proposals. DISSENS integrates a technology stack which combines privacy-friendly online payments with self-sovereign personal data management using a decentralized directory service. This enables users to be in complete control of their digital identity and personal information while at the same time being able to selectively share information necessary to easily use commercial services. Our pilot demonstrates the viability of a sustainable, user-centric, standards-compliant and accessible use case for public service employees and students in the domain of retail e-commerce. We leverage innovative technologies including self-sovereign identity, privacy credentials, and privacy-friendly digital payments in combination with established standards to provide easy-to-adapt templates for the integration of various scenarios and use cases

    A Morphological Analysis of a Hybrid Swarm of Native \u3ci\u3eUlmus rubra\u3c/i\u3e and Introduced \u3ci\u3eU. pumila\u3c/i\u3e (Ulmaceae) in Southeastern Nebraska

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    The parental species and hybrid swarm of native Ulmus rubra Muhl. and the introduced, naturalized and weedy U. pumila L. were investigated in a 65-km transect in Lancaster, Saunders, and Butler counties in Nebraska. Thirty-two trees of U. rubra, 32 of U. pumila, and 50 of the hybrid swarm were sampled for leaves and buds and subsampled for flowers and fruits. Leaves were measured for petiole length, blade length, width, primary and secondary teeth per cm, number of secondary teeth per primary tooth, and texture. Buds were scored for color and distribution of trichomes. Flowers were sampled for stamen counts and pollen size. Fruits were measured for length, width, and color and distribution of trichomes. Statistically significant differences (PUlmus × intermedia Elowsky

    Direct evidence for encoding of motion streaks in human visual cortex

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    Temporal integration in the visual system causes fast-moving objects to generate static, oriented traces ('motion streaks'), which could be used to help judge direction of motion. While human psychophysics and single-unit studies in non-human primates are consistent with this hypothesis, direct neural evidence from the human cortex is still lacking. First, we provide psychophysical evidence that faster and slower motions are processed by distinct neural mechanisms: faster motion raised human perceptual thresholds for static orientations parallel to the direction of motion, whereas slower motion raised thresholds for orthogonal orientations. We then used functional magnetic resonance imaging to measure brain activity while human observers viewed either fast ('streaky') or slow random dot stimuli moving in different directions, or corresponding static-oriented stimuli. We found that local spatial patterns of brain activity in early retinotopic visual cortex reliably distinguished between static orientations. Critically, a multivariate pattern classifier trained on brain activity evoked by these static stimuli could then successfully distinguish the direction of fast ('streaky') but not slow motion. Thus, signals encoding static-oriented streak information are present in human early visual cortex when viewing fast motion. These experiments show that motion streaks are present in the human visual system for faster motion.This work was supported by the Wellcome Trust (G.R., D.S.S.), the European Union ‘Mindbridge’ project (B.B.), the Australian Federation of Graduate Women Tempe Mann Scholarship (D.A.), the University of Sydney Campbell Perry Travel Fellowship (D.A.) and the Brain Research Trust (C.K.)

    Intermediate-term outcome after PSMA-PET guided high-dose radiotherapy of recurrent high-risk prostate cancer patients

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    Background By the use of PSMA positron emission tomography (PET) detection of prostate cancer lesions with a high sensitivity and specificity combined with a favorable lesion to background contrast is feasible. Therefore, PSMA-PET is increasingly used for planning of radiotherapy treatment; however, any data on intermediate-term outcome is missing so far. Methods Patients with high-risk or very high risk prostate cancer, referred for salvage radiotherapy (SRT, n = 22) between 2013 and 2015, underwent PSMA-PET prior to therapy. Irradiation was planned on PET data with boost to macroscopic tumors/metastases. Treatment related toxicity was measured using Common Terminology Criteria for Adverse Events (CTCAE, v4.0). Result Findings in PSMA-PET led to treatment modifications in 77% of SRT patients compared to available CT information. One patient did not receive irradiation due to disseminated disease, the other patients received increased boost doses to macroscopic disease and/or inclusion of additional target volumes. Toxicity was low as only 2 patients reported toxicities > grade 1. With a Median follow-up time of 29 in patients that were not lost to follow-up, prolonged PSA responses below baseline were observed in the majority of patients (14 of 20). In hormone-naĂŻve SRT patients (n = 11), radiotherapy led to prolonged PSA decrease in 8/11 patients, however with 3 of these 8 patients receiving repeated PSMA based irradiation of novel lesions during follow-up. Conclusion PSMA-PET guided planning of radiotherapy led to change of treatment in the majority of patients. Treatment related toxicity was well tolerated and promising results regarding intermediate-term PSA decrease were observed. Trial registration No trial registration was performed due to retrospective evaluation

    Dynamically Distributed Network Control for Message Dissemination in ITS

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    International audienceWe propose D2-ITS, a flexible and extensible framework to dynamically distribute network control to enable message dissemination in Intelligent Transport Systems (ITS). By decoupling the control- from the data plane, D2-ITS leverages network programmability to address ITS scalability, delay intolerance and decentralization. It uses a distributed control plane based on a hierarchy of controllers that can dynamically adjust to environment and network conditions in order to satisfy ITS application requirements. We demonstrate the benefits of D2-ITS through a proof-of-concept prototype using the ns-3 simulation platform. Results indicate lower message delivery latency with minimal additional overhead

    The Role of Stereotactic Radiosurgery in the Management of Foramen Magnum Meningiomas—A Multicenter Analysis and Review of the Literature

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    Background: Foramen magnum meningiomas (FMMs) represent a considerable neurosurgical challenge given their location and potential morbidity. Stereotactic radiosurgery (SRS) is an established non-invasive treatment modality for various benign and malignant brain tumors. However, reports on single-session or multisession SRS for the management and treatment of FMMs are exceedingly rare. We report the largest FMM SRS series to date and describe our multicenter treatment experience utilizing robotic radiosurgery. Methods: Patients who underwent SRS between 2005 and 2020 as a treatment for a FMM at six different centers were eligible for analysis. Results: Sixty-two patients met the inclusion criteria. The median follow-up was 28.9 months. The median prescription dose and isodose line were 14 Gy and 70%, respectively. Single-session SRS accounted for 81% of treatments. The remaining patients received three to five fractions, with doses ranging from 19.5 to 25 Gy. Ten (16%) patients were treated for a tumor recurrence after surgery, and thirteen (21%) underwent adjuvant treatment. The remaining 39 FMMs (63%) received SRS as their primary treatment. For patients with an upfront surgical resection, histopathological examination revealed 22 World Health Organization grade I tumors and one grade II FMM. The median tumor volume was 2.6 cubic centimeters. No local failures were observed throughout the available follow-up, including patients with a follow-up ≄ five years (16 patients), leading to an overall local control of 100%. Tumor volume significantly decreased after treatment, with a median volume reduction of 21% at the last available follow-up (p < 0.01). The one-, three-, and five-year progression-free survival were 100%, 96.6%, and 93.0%, respectively. Most patients showed stable (47%) or improved (21%) neurological deficits at the last follow-up. No high-grade adverse events were observed. Conclusions: SRS is an effective and safe treatment modality for FMMs. Despite the paucity of available data and previous reports, SRS should be considered for selected patients, especially those with subtotal tumor resections, recurrences, and patients not suitable for surgery

    Does Modality of Survey Administration Impact Data Quality: Audio Computer Assisted Self Interview (ACASI) Versus Self-Administered Pen and Paper?

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    BACKGROUND. In the context of a randomized controlled trial (RCT) on HIV testing in the emergency department (ED) setting, we evaluated preferences for survey modality and data quality arising from each modality. METHODS. Enrolled participants were offered the choice of answering a survey via audio computer assisted self-interview (ACASI) or pen and paper self-administered questionnaire (SAQ). We evaluated factors influencing choice of survey modality. We defined unusable data for a particular survey domain as answering fewer than 75% of the questions in the domain. We then compared ACASI and SAQ with respect to unusable data for domains that address sensitive topics. RESULTS. Of 758 enrolled ED patients, 218 (29%) chose ACASI, 343 chose SAQ (45%) and 197 (26%) opted not to complete either. Results of the log-binomial regression indicated that older (RR=1.08 per decade) and less educated participants (RR=1.25) were more likely to choose SAQ over ACASI. ACASI yielded substantially less unusable data than SAQ. CONCLUSIONS. In the ED setting there may be a tradeoff between increased participation with SAQ versus better data quality with ACASI. Future studies of novel approaches to maximize the use of ACASI in the ED setting are needed.National Institute of Mental Health (R01 MH073445, R01 MH65869

    Report and preliminary results of SONNE cruise SO175, Miami - Bremerhaven, 12.11 - 30.12.2003 : (GAP, Gibraltar Arc Processes)

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    Expedition SO175 using FS Sonne aimed for a multidisciplinerary geoscientific approach with an international group of researchers. Methods covered the entire span from geophysical data acquisition (seafloor mapping, echography, seismic reflection), sediment coring at sites of active fluid venting, in situ heat flow measurements across the entire length of the Gibraltar thrust wedge, the deformation front, landslide bodies, and mud volcanoes, and finally the deployment of a long-term pore pressure probe. Video-supported operations helped to identify fluid vent sites, regions with tectonic activity, and other attractive high priority targets. Qualitative and quantitative examinations took place on board and are continued on land with respect to pore pressure variation, geomicrobiology, sediment- and fluid mobilization, geochemical processes, faunal assemblages (e.g. cold water corals), and gas hydrates (flammable methane-ice-crystals). Main focus of the expedition has been a better understanding of interaction between dynamic processes in a seismically active region region with slow plate convergence. In the context of earthquake nucleation and subduction zone processes, the SO175 research programme had a variety of goals, such as: ‱ To test the frictional behaviour of the abyssal plain sediments. ‱ To explore the temperature field of the 1755 thrust earthquake event via heat flow measurements. ‱ To assess the role of fluid venting and gas hydrate processes control slope stability and mud volcanic activity along the Iberian continental margin. ‱ To measure isotope geochemistry of pore waters and carbonates of deep fluids. ‱ To quantify microbial activity in Gibraltar wedge sediments. ‱ To test whether microseismicity in the area corresponds to in situ pore pressure changes. ‱ To find out if enhanced heat flow max be indicative of active subduction. Initial tentative results during the cruise suggest that there is a component of active thrusting at the base of the wedge, as attested by heat flow data. Based on mostly geochemical evidence, mud volcanism was found less active than previously assumed. Highlights from post-cruise research include the successful deployment of the long-term station and high frictional resistance of all incoming sediment on the three abyssal plains
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