1,705 research outputs found

    Exploiting citation networks for large-scale author name disambiguation

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    We present a novel algorithm and validation method for disambiguating author names in very large bibliographic data sets and apply it to the full Web of Science (WoS) citation index. Our algorithm relies only upon the author and citation graphs available for the whole period covered by the WoS. A pair-wise publication similarity metric, which is based on common co-authors, self-citations, shared references and citations, is established to perform a two-step agglomerative clustering that first connects individual papers and then merges similar clusters. This parameterized model is optimized using an h-index based recall measure, favoring the correct assignment of well-cited publications, and a name-initials-based precision using WoS metadata and cross-referenced Google Scholar profiles. Despite the use of limited metadata, we reach a recall of 87% and a precision of 88% with a preference for researchers with high h-index values. 47 million articles of WoS can be disambiguated on a single machine in less than a day. We develop an h-index distribution model, confirming that the prediction is in excellent agreement with the empirical data, and yielding insight into the utility of the h-index in real academic ranking scenarios.Comment: 14 pages, 5 figure

    Spectral averaging techniques for Jacobi matrices with matrix entries

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    A Jacobi matrix with matrix entries is a self-adjoint block tridiagonal matrix with invertible blocks on the off-diagonals. Averaging over boundary conditions leads to explicit formulas for the averaged spectral measure which can potentially be useful for spectral analysis. Furthermore another variant of spectral averaging over coupling constants for these operators is presented

    Results of a LMXB survey: variation in the height of the neutron star blackbody emission region

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    We present results of a survey of the spectra of Low Mass X-ray Binaries using ASCA. It is shown that all sources in the survey are well-fitted by the same two-component emission model that we have previously shown is able to describe both the non-dip and dip spectra of the dipping class of LMXB. This model consists of point-like blackbody emission from the neutron star plus Comptonized emission from a disk-like accretion disk corona of radius typically 50,000 km. Additional data from results published elsewhere by us from BeppoSAX and ASCA are added to the survey. The large variation in blackbody luminosity of survey sources is shown to be due primarily to major changes in blackbody emitting area. Fitting a multi-temperature disk blackbody plus Comptonization model to the survey spectra requires values of inner disk radius substantially less than the neutron star radius in many cases, making disk origin of the blackbody highly unlikely. Assuming that the emission is from an equatorial strip on the neutron star, it is shown that the half-height of the strip h agrees well with the half-height H of the radiatively-supported inner accretion disk, this agreement spanning three orders of magnitude in each parameter. Possible mechanisms for the agreement are discussed, including radial accretion flow between inner disk and star, and accretion flow ``creep' on the surface of the neutron star.Comment: 10 pages, 7 ps figures; accepted for publication in A&A Main Journa

    Endothelial preconditioning by transient oxidative stress reduces inflammatory responses of cultured endothelial cells to TNF-α

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    Brief episodes of ischemia can render an organ resistant to subsequent severe ischemia. This ‘ischemic preconditioning’ is ascribed to various mechanisms, including oxidative stress. We investigated whether preconditioning exists on an endothelial level. Human umbilical vein endothelial cells (HUVECs) were transiently confronted with oxidative stress (1 mM H2O2, 5 min). Adhesion molecules ICAM-1 and E-selectin and release of cytokines IL-6 and IL-8 to subsequent stimulation with TNF-α (2.5 ng/ml, 4 h) were measured (flow cytometry and immunoassay), as were nuclear translocation of the transcription factor NFkB (Western blotting, confocal microscopy) and redox status of HUVECs (quantification of glutathione by HPLC). TNF-α elevated IL-6 in the cell supernatant from 8.8 ± 1 to 41 ± 3 pg/ml and IL-8 from 0.5 ± 0.03 to 3 ± 0.2 ng/ml. ICAM-1 was increased threefold and E-selectin rose eightfold. Oxidative stress (decrease of glutathione by 50%) reduced post-TNF-α levels of IL-6 to 14 ± 3 and IL-8 to 1 ± 0.2; the rise of ICAM-1 was completely blocked and E-selectin was only doubled. The anti-inflammatory effects of preconditioning via oxidative stress were paralleled by reduction of the translocation of NFkB on stimulation with TNF-α, and antagonized by the intracellular radical scavenger N-acetylcysteine. ‘Anti-inflammatory preconditioning’ of endothelial cells by oxidative stress may account for the inhibitory effects of preconditioning on leukocyte adhesion in vivo

    Optical properties of c-Plane InGaN/GaN single quantum wells as a function of total electric field strength

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    We present low temperature photoluminescence spectra from four InGaN/GaN single quantum well structures where the total electric field across the quantum wells was varied by the manipulation of the surface polarization field, which is of opposite sign to the electrostatic built-in field originating from spontaneous and piezoelectric polarization intrinsic to the material. We find that, overall, the photoluminescence peak emission energy increases and its full width at half maximum decreases with decreasing total internal electric field. Using an atomistic tight-binding model of a quantum well with different total internal electric fields, we find that the calculated mean and standard deviation ground state transition energies follow the same trends with field as our experimentally determined spectral peak energies and widths. Overall, we attribute this behavior to a reduction in the quantum confined Stark effect and a connected reduction in the variation of ground state transition energies with decreasing electric field, respectively

    Long-term safety, efficacy, and quality of life during adjunctive brivaracetam treatment in patients with uncontrolled epilepsy: An open-label follow-up trial.

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    Abstract Objectives The primary objective of this long-term follow-up (LTFU) trial was to evaluate the long-term safety and tolerability of brivaracetam (BRV). The secondary objective was to evaluate the maintenance of efficacy of BRV (including quality of life) over time. Methods This open-label, multicenter, flexible-dose trial (N01379 [NCT01339559]) was conducted in adults (≥16 years) with focal or generalized-onset seizures, who had participated in a placebo (PBO)-controlled trial of adjunctive BRV (N01258: NCT01405508 or N01358: NCT01261325). Results Seven hundred and sixty-six patients received BRV in this LTFU trial (753 had focal seizures and 13 had generalized-onset seizures). Kaplan–Meier-estimated retention was 71.9% at 12 months, and 53.7% at 36 months. Treatment-emergent adverse events (TEAEs) were reported by 643 (83.9%) patients, most commonly headache (104 [13.6%] patients) and dizziness (100 [13.1%] patients). Two hundred and fifty-seven (33.6%) patients had drug-related TEAEs, most commonly somnolence (49 [6.4%] patients) and dizziness (41 [5.4%] patients). Permanent discontinuation of BRV due to TEAEs occurred in 91 (11.9%) patients. Patients with focal seizures had a median percentage reduction in focal seizure frequency of 52.0% and 51.7% were 50% responders (sustained over time); 26.0% were seizurefree for 6 months, and 17.9% were seizurefree for 12 months. 42.4% of patients at 12 months and 46.8% at 24 months had clinically meaningful improvements in Patient Weighted Quality of Life in Epilepsy Questionnaire 31 total score. Conclusions In this select group of patients who entered the LTFU trial, BRV was generally safe and well tolerated. Results indicate the long-term efficacy of BRV in patients with focal seizures

    Challenging the Postwar Narrative: The Art and Agenda of Boris Lurie

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    Art history is shaped, studied, and taught based on narratives, artistic movements, and the biographies of celebrated artists. While contributing to an understanding of prevalent traditions and artists working in those traditions, these narratives are also constructions of inclusion and exclusion that establish art historical placement for certain artists while relegating others to historical obscurity. It is clear what happens to the critical fortunes of artists who are placed within these narratives. Yet what happens to the artists who do not fit within any of the categories established by these constructions? Are they then to be understood as simply minor artists or perhaps even “outsider artists?” Using the example of Boris Lurie and his critical fortune within the context of the standard art historical narrative of American art of the post World War Two period, this thesis argues for an expanded vision of modern and contemporary art that would accommodate lesser-known artists and offer a nuanced understanding of what American art has been after 1945

    Biomechanical modulation of collagen fragment-induced anabolic and catabolic activities in chondrocyte/agarose constructs

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    The present study examined the effect of collagen fragments on anabolic and catabolic activities by chondrocyte/agarose constructs subjected to dynamic compression..
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