1,775 research outputs found

    Interventional radiology virtual simulator for liver biopsy

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    Purpose Training in Interventional Radiology currently uses the apprenticeship model, where clinical and technical skills of invasive procedures are learnt during practice in patients. This apprenticeship training method is increasingly limited by regulatory restrictions on working hours, concerns over patient risk through trainees’ inexperience and the variable exposure to case mix and emergencies during training. To address this, we have developed a computer-based simulation of visceral needle puncture procedures. Methods A real-time framework has been built that includes: segmentation, physically based modelling, haptics rendering, pseudo-ultrasound generation and the concept of a physical mannequin. It is the result of a close collaboration between different universities, involving computer scientists, clinicians, clinical engineers and occupational psychologists. Results The technical implementation of the framework is a robust and real-time simulation environment combining a physical platform and an immersive computerized virtual environment. The face, content and construct validation have been previously assessed, showing the reliability and effectiveness of this framework, as well as its potential for teaching visceral needle puncture. Conclusion A simulator for ultrasound-guided liver biopsy has been developed. It includes functionalities and metrics extracted from cognitive task analysis. This framework can be useful during training, particularly given the known difficulties in gaining significant practice of core skills in patients

    Prognostic value of discharge heart rate in acute heart failure patients: More relevant in atrial fibrillation?

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    Aims: The prognostic impact of heart rate (HR) in acute heart failure (AHF) patients is not well known especially in atrial fibrillation (AF) patients. The aim of the study was to evaluate the impact of admission HR, discharge HR, HR difference (admission-discharge) in AHF patients with sinus rhythm (SR) or AF on long- term outcomes. Methods: We included 1398 patients consecutively admitted with AHF between October 2013 and December 2014 from a national multicentre, prospective registry. Logistic regression models were used to estimate the association between admission HR, discharge HR and HR difference and one- year all-cause mortality and HF readmission. Results: The mean age of the study population was 72+/-12years. Of these, 594 (42.4%) were female, 655 (77.8%) were hypertensive and 655 (46.8%) had diabetes. Among all included patients, 745 (53.2%) had sinus rhythm and 653 (46.7%) had atrial fibrillation. Only discharge HR was associated with one year all-cause mortality (Relative risk (RR)=1.182, confidence interval (CI) 95% 1.024-1.366, p=0.022) in SR. In AF patients discharge HR was associated with one year all cause mortality (RR=1.276, CI 95% 1.115-1.459, p</=0.001). We did not observe a prognostic effect of admission HR or HRD on long-term outcomes in both groups. This relationship is not dependent on left ventricular ejection fraction. Conclusions: In AHF patients lower discharge HR, neither the admission nor the difference, is associated with better long-term outcomes especially in AF patients

    Anisotropic Drag Force from 4D Kerr-AdS Black Holes

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    Using AdS/CFT we investigate the effect of angular-momentum-induced anisotropy on the instantaneous drag force of a heavy quark. The dual description is that of a string moving in the background of a Kerr-AdS black holes. The system exhibits the expected focussing of jets towards the impact parameter plane. We put forward that we can use the connection between this focussing behavior and the angular momentum induced pressure gradient to extrapolate the pressure gradient correction to the drag force that can be used for transverse elliptic flow in realistic RHIC. The result is recognizable as a relativistic pressure gradient force.Comment: 22 pages and 4 figure

    A flexible sequential learning deficit in patients with Parkinson’s disease: a 2 × 8 button-press task

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    A 2 × 8 button-press task is a sequential hand movement task in which subjects are required to press eight pairs of buttons as accurately and quickly as possible. The 2 × 8 task allows us to examine flexible sequential learning, more aptly called sequence-unselective learning. Sequence-unselective learning is observed after repeated experiences with the task, when subjects have shown good progress in learning, with new sequences as well as previously learned ones. Although cognitive inflexibility has been reported in patients with Parkinson’s disease (PD), there have been few studies investigating their flexibility in sequential learning. We examined PD patients’ ability for sequence-unselective learning through the use of a 2 × 8 button-press task. In the first session, PD patients and subjects from the control group performed a sequential 2 × 8 task until the learning criterion was fulfilled (Session 1). After 1 month, they participated in other sessions: one involving the learned sequence (Session 2) and another involving the new sequence (Session 3). We found that PD patients made more errors than the normal control subjects only when learning the new sequence (Session 3) (P < 0.01). In Session 3, control subjects reached the learning target with fewer errors than in the Session 1 (normal sequence-unselective learning), whereas the PD patients did not exhibit such an improvement. Our results revealed a sequence-unselective deficit in PD patients. The deficit may help to emphasize the cognitive and physical inflexibility of PD

    Interactive translation prediction versus conventional post-editing in practice: a study with the CasMaCat workbench

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    [EN] We conducted a field trial in computer-assisted professional translation to compare interactive translation prediction (ITP) against conventional post-editing (PE) of machine translation (MT) output. In contrast to the conventional PE set-up, where an MT system first produces a static translation hypothesis that is then edited by a professional (hence "post-editing"), ITP constantly updates the translation hypothesis in real time in response to user edits. Our study involved nine professional translators and four reviewers working with the web-based CasMaCat workbench. Various new interactive features aiming to assist the post-editor/translator were also tested in this trial. Our results show that even with little training, ITP can be as productive as conventional PE in terms of the total time required to produce the final translation. Moreover, translation editors working with ITP require fewer key strokes to arrive at the final version of their translation.This work was supported by the European Union’s 7th Framework Programme (FP7/2007–2013) under grant agreement No 287576 (CasMaCat ).Sanchis Trilles, G.; Alabau, V.; Buck, C.; Carl, M.; Casacuberta Nolla, F.; Garcia Martinez, MM.; Germann, U.... (2014). Interactive translation prediction versus conventional post-editing in practice: a study with the CasMaCat workbench. Machine Translation. 28(3-4):217-235. https://doi.org/10.1007/s10590-014-9157-9S217235283-4Alabau V, Leiva LA, Ortiz-MartĂ­nez D, Casacuberta F (2012) User evaluation of interactive machine translation systems. In: Proceedings of the 16th Annual Conference of the European Association for Machine Translation, pp 20–23Alabau V, Buck C, Carl M, Casacuberta F, GarcĂ­a-MartĂ­nez M, Germann U, GonzĂĄlez-Rubio J, Hill R, Koehn P, Leiva L, Mesa-Lao B, Ortiz-MartĂ­nez D, Saint-Amand H, Sanchis-Trilles G, Tsoukala C (2014) Casmacat: A computer-assisted translation workbench. In: Proceedings of the 14th Conference of the European Chapter of the Association for Computational Linguistics, pp 25–28Alves F, Vale D (2009) Probing the unit of translation in time: aspects of the design and development of a web application for storing, annotating, and querying translation process data. Across Lang Cultures 10(2):251–273Bach N, Huang F, Al-Onaizan Y (2011) Goodness: A method for measuring machine translation confidence. In: Proceedings of the Annual Meeting of the Association for Computational Linguistics, pp 211–219Barrachina S, Bender O, Casacuberta F, Civera J, Cubel E, Khadivi S, Lagarda AL, Ney H, TomĂĄs J, Vidal E, Vilar JM (2009) Statistical approaches to computer-assisted translation. Comput Linguist 35(1):3–28Brown PF, Della Pietra SA, Della Pietra VJ (1993) The mathematics of statistical machine translation: parameter estimation. Comput Linguist 19(2):263–311Callison-Burch C, Koehn P, Monz C, Post M, Soricut R, Specia L (2012) Findings of the 2012 workshop on statistical machine translation. In: Proceedings of the Seventh Workshop on Statistical Machine Translation, pp 10–51Carl M (2012a) The CRITT TPR-DB 1.0: A database for empirical human translation process research. In: Proceedings of the AMTA 2012 Workshop on Post-Editing Technology and Practice, pp 1–10Carl M (2012b) Translog-II: a program for recording user activity data for empirical reading and writing research. In: Proceedings of the Eighth International Conference on Language Resources and Evaluation, pp 4108–4112Carl M (2014) Produkt- und Prozesseinheiten in der CRITT Translation Process Research Database. In: Ahrens B (ed) Translationswissenschaftliches Kolloquium III: BeitrĂ€ge zur Übersetzungs- und Dolmetschwissenschaft (Köln/Germersheim). Peter Lang, Frankfurt am Main, pp 247–266Carl M, Kay M (2011) Gazing and typing activities during translation : a comparative study of translation units of professional and student translators. Meta 56(4):952–975Doherty S, O’Brien S, Carl M (2010) Eye tracking as an MT evaluation technique. Mach Transl 24(1):1–13Elming J, Carl M, Balling LW (2014) Investigating user behaviour in post-editing and translation using the Casmacat workbench. In: O’Brien S, Winther Balling L, Carl M, Simard M, Specia L (eds) Post-editing of machine translation: processes and applications. Cambridge Scholar Publishing, Newcastle upon Tyne, pp 147–169Federico M, Cattelan A, Trombetti M (2012) Measuring user productivity in machine translation enhanced computer assisted translation. In: Proceedings of the Tenth Biennial Conference of the Association for Machine Translation in the AmericasFlournoy R, Duran C (2009) Machine translation and document localization at adobe: From pilot to production. In: Proceedings of MT Summit XIIGreen S, Heer J, Manning CD (2013) The efficacy of human post-editing for language translation. In: Proceedings of SIGCHI Conference on Human Factors in Computing Systems, pp 439–448Guerberof A (2009) Productivity and quality in mt post-editing. In: Proceedings of MT Summit XII-Workshop: Beyond Translation Memories: New Tools for Translators MTGuerberof A (2012) Productivity and quality in the post-editing of outputs from translation memories and machine translation. Ph.D. ThesisJust MA, Carpenter PA (1980) A theory of reading: from eye fixations to comprehension. Psychol Rev 87(4):329Koehn P (2009a) A process study of computer-aided translation. Mach Transl 23(4):241–263Koehn P (2009b) A web-based interactive computer aided translation tool. In: Proceedings of ACL-IJCNLP 2009 Software Demonstrations, pp 17–20Krings HP (2001) Repairing texts: empirical investigations of machine translation post-editing processes, vol 5. Kent State University Press, KentLacruz I, Shreve GM, Angelone E (2012) Average pause ratio as an indicator of cognitive effort in post-editing: a case study. In: Proceedings of the AMTA 2012 Workshop on Post-Editing Technology and Practice, pp 21–30Langlais P, Foster G, Lapalme G (2000) Transtype: A computer-aided translation typing system. In: Proceedings of the 2000 NAACL-ANLP Workshop on Embedded Machine Translation Systems, pp 46–51Leiva LA, Alabau V, Vidal E (2013) Error-proof, high-performance, and context-aware gestures for interactive text edition. In: Proceedings of the 2013 annual conference extended abstracts on Human factors in computing systems, pp 1227–1232Montgomery D (2004) Introduction to statistical quality control. Wiley, HobokenO’Brien S (2009) Eye tracking in translation process research: methodological challenges and solutions, Copenhagen Studies in Language, vol 38. Samfundslitteratur, Copenhagen, pp 251–266Ortiz-MartĂ­nez D, Casacuberta F (2014) The new Thot toolkit for fully automatic and interactive statistical machine translation. In: Proceedings of the 14th Annual Meeting of the European Association for Computational Linguistics: System Demonstrations, pp 45–48Plitt M, Masselot F (2010) A productivity test of statistical machine translation post-editing in a typical localisation context. 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    Measurement of the branching fraction and CP content for the decay B(0) -> D(*+)D(*-)

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    This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APS.We report a measurement of the branching fraction of the decay B0→D*+D*- and of the CP-odd component of its final state using the BABAR detector. With data corresponding to an integrated luminosity of 20.4  fb-1 collected at the ΄(4S) resonance during 1999–2000, we have reconstructed 38 candidate signal events in the mode B0→D*+D*- with an estimated background of 6.2±0.5 events. From these events, we determine the branching fraction to be B(B0→D*+D*-)=[8.3±1.6(stat)±1.2(syst)]×10-4. The measured CP-odd fraction of the final state is 0.22±0.18(stat)±0.03(syst).This work is supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the A.P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation

    Search for Pair Production of Scalar Top Quarks Decaying to a tau Lepton and a b Quark in ppbar Collisions at sqrt{s}=1.96 TeV

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    We search for pair production of supersymmetric top quarks (~t_1), followed by R-parity violating decay ~t_1 -> tau b with a branching ratio beta, using 322 pb^-1 of ppbar collisions at sqrt{s}=1.96 TeV collected by the CDF II detector at Fermilab. Two candidate events pass our final selection criteria, consistent with the standard model expectation. We set upper limits on the cross section sigma(~t_1 ~tbar_1)*beta^2 as a function of the stop mass m(~t_1). Assuming beta=1, we set a 95% confidence level limit m(~t_1)>153 GeV/c^2. The limits are also applicable to the case of a third generation scalar leptoquark (LQ_3) decaying LQ_3 -> tau b.Comment: 7 pages, 2 eps figure

    Measurement of D-s(+) and D-s(*+) production in B meson decays and from continuum e(+)e(-) annihilation at √s=10.6 GeV

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    This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APSNew measurements of Ds+ and Ds*+ meson production rates from B decays and from qq̅ continuum events near the ΄(4S) resonance are presented. Using 20.8 fb-1 of data on the ΄(4S) resonance and 2.6 fb-1 off-resonance, we find the inclusive branching fractions B(B⃗Ds+X)=(10.93±0.19±0.58±2.73)% and B(B⃗Ds*+X)=(7.9±0.8±0.7±2.0)%, where the first error is statistical, the second is systematic, and the third is due to the Ds+→φπ+ branching fraction uncertainty. The production cross sections σ(e+e-→Ds+X)×B(Ds+→φπ+)=7.55±0.20±0.34pb and σ(e+e-→Ds*±X)×B(Ds+→φπ+)=5.8±0.7±0.5pb are measured at center-of-mass energies about 40 MeV below the ΄(4S) mass. The branching fractions ÎŁB(B⃗Ds(*)+D(*))=(5.07±0.14±0.30±1.27)% and ÎŁB(B⃗Ds*+D(*))=(4.1±0.2±0.4±1.0)% are determined from the Ds(*)+ momentum spectra. The mass difference m(Ds+)-m(D+)=98.4±0.1±0.3MeV/c2 is also measured.This work was supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the Swiss NSF, A. P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation

    Evidence for an excess of B -> D(*) Tau Nu decays

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    Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or mu. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) = 0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0 sigma and 2.7 sigma, respectively. Taken together, our results disagree with these expectations at the 3.4 sigma level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. We also report the observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.Comment: Expanded section on systematics, text corrections, improved the format of Figure 2 and included the effect of the change of the Tau polarization due to the charged Higg

    Search for a Technicolor omega_T Particle in Events with a Photon and a b-quark Jet at CDF

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    If the Technicolor omega_T particle exists, a likely decay mode is omega_T -> gamma pi_T, followed by pi_T -> bb-bar, yielding the signature gamma bb-bar. We have searched 85 pb^-1 of data collected by the CDF experiment at the Fermilab Tevatron for events with a photon and two jets, where one of the jets must contain a secondary vertex implying the presence of a b quark. We find no excess of events above standard model expectations. We express the result of an exclusion region in the M_omega_T - M_pi_T mass plane.Comment: 14 pages, 2 figures. Available from the CDF server (PS with figs): http://www-cdf.fnal.gov/physics/pub98/cdf4674_omega_t_prl_4.ps FERMILAB-PUB-98/321-
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