4,809 research outputs found

    Harvesting Entities from the Web Using Unique Identifiers -- IBEX

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    In this paper we study the prevalence of unique entity identifiers on the Web. These are, e.g., ISBNs (for books), GTINs (for commercial products), DOIs (for documents), email addresses, and others. We show how these identifiers can be harvested systematically from Web pages, and how they can be associated with human-readable names for the entities at large scale. Starting with a simple extraction of identifiers and names from Web pages, we show how we can use the properties of unique identifiers to filter out noise and clean up the extraction result on the entire corpus. The end result is a database of millions of uniquely identified entities of different types, with an accuracy of 73--96% and a very high coverage compared to existing knowledge bases. We use this database to compute novel statistics on the presence of products, people, and other entities on the Web.Comment: 30 pages, 5 figures, 9 tables. Complete technical report for A. Talaika, J. A. Biega, A. Amarilli, and F. M. Suchanek. IBEX: Harvesting Entities from the Web Using Unique Identifiers. WebDB workshop, 201

    Nuclear bars and blue nuclei within barred spiral galaxies

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    Multicolour near IR photometry for a sample of 32 large barred spiral galaxies is presented. By applying ellipse fitting techniques, we identify significant isophote twists with respect to the primary bar axis in the nuclear regions of \sim70 \%\ of the sample. These twists are identified in galaxies as late as SBbc and are clearly distinguishable from spiral arm morphology. At most seven of the galaxies with isophote twists are inferred to possess secondary (nuclear) bars, the axis ratios of which appear to correlate with morphological type. The remainder may result from triaxial bulges, or from oblate bulges misaligned with the primary bar. The near IR colour distributions in these data show evidence for (red) circumnuclear star forming rings in 4 galaxies. The majority of the sample (19) also possess striking blue nuclear regions, bluer than typical old stellar populations by \sim0.3 mag. in (J--H) and \sim0.23 mag. in (H--K). Such blue colours do not appear to correlate with the presence of nuclear rings or pseudo--rings, nor with the activity of the host galaxy (as determined from emission--line spectroscopic characteristics). Several mechanisms to explain this blue colour are considered.Comment: 24 pages plain LaTex( including table captions), 5 tables and 18 figures. Accepted for publication in MNRAS. Paper and tables available via anonymous ftp://143.167.4.101/pub/papers as sqiid-paper.tex and table1,2,3.tex, table4.ps, table5.ps. Figures available as postcript upon request to first Autho

    Beidseitige Ertaubung durch Labyrinthitis bei M.Crohn

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    Zusammenfassung: Vestibulocochleäre Störungen bei chronischen Darmentzündungen sind seltene, aber immer wieder beschriebene Komplikationen oder Manifestationen der Grunderkrankung. Ein 26-jähriger Mann erlitt unter immunsuppressiver Therapie aufgrund eines 6Monate zuvor diagnostizierten M.Crohn einen bilateralen Ausfall der Gleichgewichtsorgane sowie eine bilaterale sensorineurale Hörminderung. Es wurde eine ausführliche Diagnostik (Audiogramm, Sprachaudiogramm, kalorische Vestibularisprüfung, Messung vestibulär evozierter myogener Potenziale, Magnetresonanztomographie) durchgeführt. Therapiert wurde mit Azathioprim, Glukokortikoiden systemisch und intratympanal sowie mit monoklonalen Antikörpern. Darunter zeigte sich ein stark fluktuierender, aber progredienter Verlauf der Beschwerden und Befunde bei nur geringfügiger bis keiner Besserung. Erst die beidseitige Versorgung mit einem Cochleaimplantaten (CI) stellte eine befriedigende Lösung dar. Das Fallbeispiel zeigt diagnostische und therapeutische Möglichkeiten und Grenzen einer immunbedingten Erkrankung. Sie verlangt eine enge interdisziplinäre Zusammenarbeit. Bei beidseitiger Ertaubung ist die frühzeitige CI-Versorgung eine geeignete Form der Rehabilitatio

    Integrating e-learning into postgraduate radiotherapy and oncology education: a case study

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    Training health professionals within University environments has traditionally focused on face-to-face methods. Practitioners working within the UK National Health Service (NHS) have found it difficult to gain leave from work to attend for study due to the demands of the NHS and staff shortages. In response, we developed a distance e learning course to match our current traditional taught programme.The first e learning module (a research methods module) was comparable in content to the traditional taught module, and developed to incorporate a formative assessment design throughout; embodying the Constructivist approach and the principle of assessment for learning. We evaluated student experiences with the e learning module using a pre and post module questionnaire, with the taught cohort used as a comparison. We tested the importance of support, levels of information technology (IT) skills, preferences for e learning and intrinsic motivation. The results identified that highly satisfied e learning students were more likely to report a preference for e learning initially, show higher levels of intrinsic motivation and report good support from tutors and fellow students. This article discusses the development and evaluation of the pilot module and some of the lessons learned from providing e learning to health workers

    Quasi-chemical study of Be2+^{2+}(aq) speciation

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    Be2+^{2+}(aq) hydrolysis can to lead to the formation of multi-beryllium clusters, but the thermodynamics of this process has not been resolved theoretically. We study the hydration state of an isolated Be2+^{2+} ion using both the quasi-chemical theory of solutions and ab initio molecular dynamics. These studies confirm that Be2+^{2+}(aq) is tetra-hydrated. The quasi-chemical approach is then applied to then the deprotonation of Be(H_2O)_4^{2+}} to give BeOH(H_2O)_3{}^{+}}. The calculated pKa_a of 3.8 is in good agreement with the experimentally suggested value around 3.5. The calculated energetics for the formation of BeOHBe3+^{3+} are then obtained in fair agreement with experiments.Comment: 11 pages, 3 figure

    Kinetic-energy release in Coulomb explosion of metastable C3H52+

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    C3H52+, formed by electron impact ionization of propane, undergoes metastable decay into C2H2++CH3+. We have monitored this reaction in a magnetic mass spectrometer of reversed geometry that is equipped with two electric sectors (BEE geometry). Three different techniques were applied to identify the fragment ions and determine the kinetic-energy release (KER) of spontaneous Coulomb explosion of C3H52+ in the second and third field free regions of the mass spectrometer. The KER distribution is very narrow, with a width of about 3% [root-mean square standard deviation]. An average KER of 4.58+/-0.15 eV is derived from the distribution. High level ab initio quantum-chemical calculations of the structure and energetics of C3H52+ are reported. The activation barrier of the reverse reaction, CH3++C2H2+ (vinylidene), is computed. The value closely agrees with the experimental average KER, thus indicating that essentially all energy available in the reaction is partitioned into kinetic energy. (C) 2003 American Institute of Physics

    Formation of even-numbered hydrogen cluster cations in ultracold helium droplets

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    Neutral hydrogen clusters are grown in ultracold helium nanodroplets by successive pickup of hydrogen molecules. Even-numbered hydrogen cluster cations are observed upon electron-impact ionization with and without attached helium atoms and in addition to the familiar odd-numbered H(n)(+). The helium matrix affects the fragmentation dynamics that usually lead to the formation of overwhelmingly odd-numbered H(n)(+). The use of high-resolution mass spectrometry allows the unambiguous identification of even-numbered H(n)(+) up to n congruent to 120 by their mass excess that distinguishes them from He(n)(+), mixed He(m)H(n)(+), and background ions. The large range in size of these hydrogen cluster ions is unprecedented, as is the accuracy of their definition. Apart from the previously observed magic number n = 6, pronounced drops in the abundance of even-numbered cluster ions are seen at n = 30 and 114, which suggest icosahedral shell closures at H(6)(+)(H(2))(12) and H(6)(+)(H(2))(54). Possible isomers of H(6)(+) are identified at the quadratic configuration interaction with inclusion of single and double excitations (QCISD)/aug-cc-pVTZ level of theory (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3035833

    Metastable anions of dinitrobenzene: resonances for electron attachment and kinetic energy release

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    Attachment of free, low-energy electrons to dinitrobenzene (DNB) in the gas phase leads to DNB as well as several fragment anions. DNB, (DNB-H), (DNB-NO), (DNB-2NO), and (DNB-NO(2)) are found to undergo metastable (unimolecular) dissociation. A rich pattern of resonances in the yield of these metastable reactions versus electron energy is observed; some resonances are highly isomer-specific. Most metastable reactions are accompanied by large average kinetic energy releases (KER) that range from 0.5 to 1.32 eV, typical of complex rearrangement reactions, but (1,3-DNB-H)(-) features a resonance with a KER of only 0.06 eV for loss of NO. (1,3-DNB-NO)(-) offers a rare example of a sequential metastable reaction, namely, loss of NO followed by loss of CO to yield C(5)H(4)O(-) with a large KER of 1.32 eV. The G4(MP2) method is applied to compute adiabatic electron affinities and reaction energies for several of the observed metastable channels. (C) 2010 American Institute of Physics. [doi:10.1063/1.3514931
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