424 research outputs found

    Eikonal representation in the momentum-transfer space

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    By means of empirical fits to the differential cross section data on pp and p(bar)p elastic scattering, above 10 GeV (center-of-mass energy), we determine the eikonal in the momentum - transfer space (q^2- space). We make use of a numerical method and a novel semi-analytical method, through which the uncertainties from the fit parameters can be propagated up to the eikonal in the q2q^2- space. A systematic study of the effect of the experimental information at large values of the momentum transfer is developed and discussed in detail. We present statistical evidence that the imaginary part of the eikonal changes sign in the q^2- space and that the position of the zero decreases as the energy increases; after the position of the zero, the eikonal presents a minimum and then goes to zero through negative values. We discuss the applicability of our results in the phenomenological context, outlining some connections with nonperturbative QCD. A short review and a critical discussion on the main results concerning "model-independent" analyses are also presented.Comment: 18 pages, 17 figures, 4 tables, svjour.cls. Revised discussion on the proton's electromagnetic form factor and references added. To appear in Eur. Phys. J.

    Chiral bosonization for non-commutative fields

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    A model of chiral bosons on a non-commutative field space is constructed and new generalized bosonization (fermionization) rules for these fields are given. The conformal structure of the theory is characterized by a level of the Kac-Moody algebra equal to (1+θ2)(1+ \theta^2) where θ\theta is the non-commutativity parameter and chiral bosons living in a non-commutative fields space are described by a rational conformal field theory with the central charge of the Virasoro algebra equal to 1. The non-commutative chiral bosons are shown to correspond to a free fermion moving with a speed equal to c=c1+θ2 c^{\prime} = c \sqrt{1+\theta^2} where cc is the speed of light. Lorentz invariance remains intact if cc is rescaled by ccc \to c^{\prime}. The dispersion relation for bosons and fermions, in this case, is given by ω=ck\omega = c^{\prime} | k|.Comment: 16 pages, JHEP style, version published in JHE

    Thinking with Sound: Exploring the Experience of Listening to an Ultrasonic Art Installation

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    Entanglement theories are well established in HCI discourse. These involve a commitment to view human experience in encounters with technology as relational and contingent, and research appara- tuses as co-producers rather than passive observers of phenomena. In this paper, we argue that sound is the sensory modality best suited to the investigation of entanglements. Materialist theories of sound and listening guide both the design of a novel interactive sound installation and the methodological approach of a participant study exploring the experience of listening. We present a diffrac- tive analysis whereby micro-phenomenological interview data is read with sonic theories, generating accounts that might other- wise remain mute: the temporal fluctuation and physical feeling of proximity in listener entanglements with sound, somatic intention setting, and plural interpretations of interactivity. Finally, we offer a series of provocations for HCI to embrace qualities of the sonic and consider epistemological positions grounded in other sense modalities

    Shorter Disease Duration Is Associated With Higher Rates of Response to Vedolizumab in Patients With Crohn\u27s Disease But Not Ulcerative Colitis.

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    BACKGROUND & AIMS: Patients with Crohn\u27s disease (CD), but not ulcerative colitis (UC), of shorter duration have higher rates of response to tumor necrosis factor (TNF) antagonists than patients with longer disease duration. Little is known about the association between disease duration and response to other biologic agents. We aimed to evaluate response of patients with CD or UC to vedolizumab, stratified by disease duration. METHODS: We analyzed data from a retrospective, multicenter, consortium of patients with CD (n = 650) or UC (n = 437) treated with vedolizumab from May 2014 through December 2016. Using time to event analyses, we compared rates of clinical remission, corticosteroid-free remission (CSFR), and endoscopic remission between patients with early-stage (≤2 years duration) and later-stage (\u3e2 years) CD or UC. We used Cox proportional hazards models to identify factors associated with outcomes. RESULTS: Within 6 months initiation of treatment with vedolizumab, significantly higher proportions of patients with early-stage CD, vs later-stage CD, achieved clinical remission (38% vs 23%), CSFR (43% vs 14%), and endoscopic remission (29% vs 13%) (P \u3c .05 for all comparisons). After adjusting for disease-related factors including previous exposure to TNF antagonists, patients with early-stage CD were significantly more likely than patients with later-stage CD to achieve clinical remission (adjusted hazard ratio [aHR], 1.59; 95% CI, 1.02-2.49), CSFR (aHR, 3.39; 95% CI, 1.66-6.92), and endoscopic remission (aHR, 1.90; 95% CI, 1.06-3.39). In contrast, disease duration was not a significant predictor of response among patients with UC. CONCLUSIONS: Patients with CD for 2 years or less are significantly more likely to achieve a complete response, CSFR, or endoscopic response to vedolizumab than patients with longer disease duration. Disease duration does not associate with response vedolizumab in patients with UC
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