1,001 research outputs found

    From Pope Urban VIII to Bishop Étienne Tempier : the strange history of the doctrine of ‘double truth’

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    In 1633 pope Urban VIII received from the Jesuit theologian Melchior Inchofer the Tractatus syllepticus, expressly conceived as a justification of the sentence against Galileo. Inchofer refers to the bull Apostolici regiminis, published in 1513 by pope Leo X, in order to argue that \u201ctruth does not contradict truth\u201d, and therefore Copernicans are not allowed to use the \u201cartful distinction\u201d between what can be said \u201caccording to philosophy\u201d and what can be said \u201caccording to theology\u201d. It is well known that the aforementioned distinction had been widely used by Aristotelian philosophers from mid-thirteenth century onwards; and for a long time it was presented by historians as the hallmark of the so-called \u2018Averroism\u2019, which was supposed to accept a \u2018double-truth theory\u2019 claiming that a doctrine could be true for philosophy while being false for theology (or vice versa). This paper shows that the roots of the principle of the unity of truth, sanctioned by Leo X in his attack against masters of philosophy who supported the \u2018Alexandrist\u2019 and the \u2018Averroist \u2019 interpretations of Aristotle\u2019s psychology, can be found not only in Aristotle\u2019s but also in Averroes\u2019 works; that Averroes gave it one of its clearest formulations; and that he had no significant impact on the way of understanding the relationship between philosophy and religious beliefs suggested by thirteenth-century Parisian Arts masters generally labelled as \u2018Latin Averroists\u2019. Rebuked in 1277 by bishop Tempier for holding that there are \u201ctwo contrary truths\u201d, these masters tried indeed to avoid the conflict between Aristotle\u2019s philosophy and the teachings of Christian faith using Aristotelian logical tools. However one evaluates their strategy, it seems clear that it was within Latin Christian thought that the different conceptions of the dialectic between \u2018reason\u2019 and \u2018faith\u2019 generated the phantom of \u2018double truth\u2019

    Leading strategies in competitive on-line prediction

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    We start from a simple asymptotic result for the problem of on-line regression with the quadratic loss function: the class of continuous limited-memory prediction strategies admits a "leading prediction strategy", which not only asymptotically performs at least as well as any continuous limited-memory strategy but also satisfies the property that the excess loss of any continuous limited-memory strategy is determined by how closely it imitates the leading strategy. More specifically, for any class of prediction strategies constituting a reproducing kernel Hilbert space we construct a leading strategy, in the sense that the loss of any prediction strategy whose norm is not too large is determined by how closely it imitates the leading strategy. This result is extended to the loss functions given by Bregman divergences and by strictly proper scoring rules.Comment: 20 pages; a conference version is to appear in the ALT'2006 proceeding

    Artificial neural network analysis of bone quality DXA parameters response to teriparatide in fractured osteoporotic patients

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    Teriparatide is a bone-forming therapy for osteoporosis that increases bone quantity and texture, with uncertain action on bone geometry. No data are available regarding its influence on bone strain. To investigate teriparatide action on parameters of bone quantity and quality and on Bone Strain Index (BSI), also derived from DXA lumbar scan, based on the mathematical model finite element method. Forty osteoporotic patients with fractures were studied before and after two years of daily subcutaneous 20 mcg of teriparatide with dual X-ray photon absorptiometry to assess bone mineral density (BMD), hip structural analysis (HSA), trabecular bone score (TBS), BSI. Spine deformity index (SDI) was calculated from spine X-ray. Shapiro-Wilks, Wilcoxon and Student's t test were used for classical statistical analysis. Auto Contractive Map was used for Artificial Neural Network Analysis (ANNs). In the entire population, the ameliorations after therapy regarded BSI (-13.9%), TBS (5.08%), BMD (8.36%). HSA parameters of femoral shaft showed a worsening. Dividing patients into responders (BMD increase >10%) and non-responders, the first presented TBS and BSI ameliorations (11.87% and -25.46%, respectively). Non-responders presented an amelioration of BSI only, but less than in the other subgroup (-6.57%). ANNs maps reflect the mentioned bone quality improvements. Teriparatide appears to ameliorate not only BMD and TBS, but also BSI, suggesting an increase of bone strength that may explain the known reduction in fracture risk, not simply justified by BMD increase. BSI appears to be a sensitive index of TPD effect. ANNs appears to be a valid tool to investigate complex clinical systems

    Nearby early-type galaxies with ionized gas. The UV emission from GALEX observations

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    We present GALEX far-ultraviolet (FUV, λeff\lambda_{eff}=1538 \AA) and near-ultraviolet (NUV, λeff\lambda_{eff}=2316 \AA) surface photometry of 40 early-type galaxies (ETGs) selected from a wider sample of 65 nearby ETGs showing emission lines in their optical spectra. We derive FUV and NUV surface brightness profiles, (FUV-NUV) colour profiles and D25_{25} integrated magnitudes. We extend the photometric study to the optical {\it r} band from SDSS imaging for 14 of these ETGs. In general, the (FUV-NUV) radial colour profiles become redder with galactocentric distance in both rejuvenated (4\leq 4 Gyr) and old ETGs. Colour profiles of NGC 1533, NGC 2962, NGC 2974, NGC 3489, and IC 5063 show rings and/or arm-like structures, bluer than the body of the galaxy, suggesting the presence of recent star formation. Although seven of our ETGs show shell systems in their optical image, only NGC 7135 displays shells in the UV bands. We characterize the UV and optical surface brightness profiles, along the major axis, using a Sersic law. The Sersic law exponent, nn, varies from 1 to 16 in the UV bands. S0 galaxies tend to have lower values of nn (5\leq5). The Sersic law exponent n=4n=4 seems to be a watershed: ETGs with n>4n>4 tend to have [α\alpha/Fe] greater than 0.15, implying a short star-formation time scale. We find a significant correlation between the FUV-NUV colour and central velocity dispersions σ\sigma, with the UV colours getting bluer at larger σ\sigma. This trend is likely driven by a combined effect of `downsizing' and of the mass-metallicity relation.Comment: Accepted for publication in MNRAS, 33 pages, 7 figure

    Clinical and imaging outcome of osteochondral lesions of the talus treated using autologous matrix-induced chondrogenesis technique with a biomimetic scaffold

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    Background: The purpose of our study was to assess the clinical and imaging outcome of autologous matrix-induced chondrogenesis (AMIC) technique consisting of microfractures followed by the filling of osteochondral lesions of the talus (OLTs) with a cell-free biphasic collagen-hydroxyapatite osteochondral scaffold (MaioRegen). Methods: Sixteen patients (eight males, age: 42.6 \ub1 18.4, range 14\u201374) with OLT repaired using AMIC technique, with implantation of MaioRegen, were clinically evaluated through the American Orthopedic Foot and Ankle Society Score (AOFAS) and a 10-point Visual Analogue Scale (VAS) pain score after a mean follow-up of 30 \ub1 16.9 months. The MRI examinations were performed 12 and 24 months after surgery. A paired t-test was applied to compare pre- and post-operative clinical findings (VAS and AOFAS) and Magnetic resonance observation of cartilage repair tissue (MOCART) score changes in the follow-up. To assess the correlation between variation of AOFAS and MOCART scores, the Pearson\u2019s correlation coefficient was calculated. Results: No complications after surgery were encountered. From pre-operative to post-operative values, there was a significant (P < 0.001) reduction of mean VAS pain score (6.3 \ub1 0.9,range: 4\u20138 and 2.9 \ub1 1.8,range: 0\u20136, respectively) and increase of AOFAS score (60.2 \ub1 7.8,range: 50\u201374 and 77.4 \ub1 16.2,range: 50\u2013100, respectively). Among 16 patients, six (37%) were not satisfied at the end of follow-up, six (37%) were moderately satisfied and four (25%) were highly satisfied. The treatment was considered failed in five out of 16 patients (31%). Among them, four (25%) required re-interventions with implantation of ankle prostheses, whereas one patient was treated with a further AMIC technique combined with autologous bone graft and platelet-rich plasma. The mean MOCART score was 41.9 \ub1 14.6 (25\u201370) 12 months after surgery and 51.9 \ub1 11.6 (30\u201370) after 24 months, with a statistically significant increase (P = 0.012). However, no correlation was seen between AOFAS and MOCART changes (r = 0.215, p = 0.609). Conclusion: The high rates of treatment failure encountered in our study using MaioRegen need to be confirmed by larger studies and should induce the scientific community questioning the reliability of this biomimetic scaffold for the treatment of OLTs

    Observation of exclusive DVCS in polarized electron beam asymmetry measurements

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    We report the first results of the beam spin asymmetry measured in the reaction e + p -> e + p + gamma at a beam energy of 4.25 GeV. A large asymmetry with a sin(phi) modulation is observed, as predicted for the interference term of Deeply Virtual Compton Scattering and the Bethe-Heitler process. The amplitude of this modulation is alpha = 0.202 +/- 0.028. In leading-order and leading-twist pQCD, the alpha is directly proportional to the imaginary part of the DVCS amplitude.Comment: 6 pages, 5 figure

    Complete measurement of three-body photodisintegration of 3He for photon energies between 0.35 and 1.55 GeV

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    The three-body photodisintegration of 3He has been measured with the CLAS detector at Jefferson Lab, using tagged photons of energies between 0.35 GeV and 1.55 GeV. The large acceptance of the spectrometer allowed us for the first time to cover a wide momentum and angular range for the two outgoing protons. Three kinematic regions dominated by either two- or three-body contributions have been distinguished and analyzed. The measured cross sections have been compared with results of a theoretical model, which, in certain kinematic ranges, have been found to be in reasonable agreement with the data.Comment: 22 pages, 25 eps figures, 2 tables, submitted to PRC. Modifications: removed 2 figures, improvements on others, a few minor modifications to the tex

    A Kinematically Complete Measurement of the Proton Structure Function F2 in the Resonance Region and Evaluation of Its Moments

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    We measured the inclusive electron-proton cross section in the nucleon resonance region (W < 2.5 GeV) at momentum transfers Q**2 below 4.5 (GeV/c)**2 with the CLAS detector. The large acceptance of CLAS allowed for the first time the measurement of the cross section in a large, contiguous two-dimensional range of Q**2 and x, making it possible to perform an integration of the data at fixed Q**2 over the whole significant x-interval. From these data we extracted the structure function F2 and, by including other world data, we studied the Q**2 evolution of its moments, Mn(Q**2), in order to estimate higher twist contributions. The small statistical and systematic uncertainties of the CLAS data allow a precise extraction of the higher twists and demand significant improvements in theoretical predictions for a meaningful comparison with new experimental results.Comment: revtex4 18 pp., 12 figure

    eta-prime photoproduction on the proton for photon energies from 1.527 to 2.227 GeV

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    Differential cross sections for the reaction gamma p -> eta-prime p have been measured with the CLAS spectrometer and a tagged photon beam with energies from 1.527 to 2.227 GeV. The results reported here possess much greater accuracy than previous measurements. Analyses of these data indicate for the first time the coupling of the etaprime N channel to both the S_11(1535) and P_11(1710) resonances, known to couple strongly to the eta N channel in photoproduction on the proton, and the importance of j=3/2 resonances in the process.Comment: 6 pages, 3 figure
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