835 research outputs found

    A JKO splitting scheme for Kantorovich-Fisher-Rao gradient flows

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    In this article we set up a splitting variant of the JKO scheme in order to handle gradient flows with respect to the Kantorovich-Fisher-Rao metric, recently introduced and defined on the space of positive Radon measure with varying masses. We perform successively a time step for the quadratic Wasserstein/Monge-Kantorovich distance, and then for the Hellinger/Fisher-Rao distance. Exploiting some inf-convolution structure of the metric we show convergence of the whole process for the standard class of energy functionals under suitable compactness assumptions, and investigate in details the case of internal energies. The interest is double: On the one hand we prove existence of weak solutions for a certain class of reaction-advection-diffusion equations, and on the other hand this process is constructive and well adapted to available numerical solvers.Comment: Final version, to appear in SIAM SIM

    Atmospheric Neutrino Fluxes

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    This talk is a status report on calculations of the flux of atmospheric neutrinos from the sub-GeV range to E_\nu ~ PeV. In the lower energy range (E_\nu < 1 TeV) the primary interest is in using the atmospheric neutrino beam to study neutrino oscillations. In the TeV range and above, atmospheric neutrinos are a calibration source and background for neutrino telescopes.Comment: 9 pages, 10 figures, for Proceedings of Neutrino 200

    Resolving parameter degeneracies in long-baseline experiments by atmospheric neutrino data

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    In this work we show that the physics reach of a long-baseline (LBL) neutrino oscillation experiment based on a superbeam and a megaton water Cherenkov detector can be significantly increased if the LBL data are combined with data from atmospheric neutrinos (ATM) provided by the same detector. ATM data are sensitive to the octant of Ξ23\theta_{23} and to the type of the neutrino mass hierarchy, mainly through three-flavor effects in e-like events. This allows to resolve the so-called Ξ23\theta_{23}- and sign(Δm312\Delta m^2_{31})-parameter degeneracies in LBL data. As a consequence it becomes possible to distinguish the normal from the inverted neutrino mass ordering at 2σ2\sigma CL from a combined LBL+ATM analysis if sin⁥22Ξ13≳0.02\sin^2 2\theta_{13} \gtrsim 0.02. The potential to identify the true values of sin⁥22Ξ13\sin^2 2\theta_{13} and the CP-phase ÎŽcp\delta_{cp} is significantly increased through the lifting of the degeneracies. These claims are supported by a detailed simulation of the T2K (phase II) LBL experiment combined with a full three-flavor analysis of ATM data in the HyperKamiokande detector.Comment: 25 pages, 10 figure

    Estonian Identity Construction Between Nation Branding and Building

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    Whilst most accounts of nation branding emphasize the economic and diplomatic relevance of the phenomenon, this article examines the way Estonia has been proposing a nation “branding + building” strategy. Drawing from an empirical study of 1) evolving campaigns of Enterprise Estonia; 2) the leverage of the national e-Residency program in attracting foreign investment; and 3) tourist and marketing strategies based on the revisiting of ‘Estonian’ culinary tradition, we look at the way official narratives have been claiming, with the help of nation branding elements, that the country has quickly de-Sovietized and that there is a new understanding of the Estonian nation and “Estonianness”. This is intended to eventually prompt a reflection on the relationship between nation-building and nation branding, which can, in some circumstances, overlap and influence identity construction at the domestic and international level

    Noninvasive stress testing of myocardial perfusion defects: head-to-head comparison of thallium-201 SPECT to MRI perfusion

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    Background: To evaluate the diagnostic value of magnetic resonance imaging (MRI) of myocardial perfusion in the assessment of flow-limiting epicardial stenosis in a head-to-head comparison with abnormal thallium-201 (201TI) single photon emission tomography (SPECT) studies in patients with predominantly known coronary artery disease (CAD). Methods and Results: Twenty-one patients (mean age 65±10years) with reversible myocardial perfusion defects on 201TI-SPECT images during dipyridamole-stimulated hyperemia were recruited for study purpose. Within 5days of the 201TI-SPECT study, myocardial perfusion was studied again with MRI during dipyridamole stimulation and at rest. Overall, 201TI-SPECT identified 30 reversible regional perfusion defects. The sensitivity to detect hypoperfused segments was 70% (21/30) with the GRE-MRI perfusion analysis with 201TI-SPECT as reference. When patients were subgrouped according to the extent of regional reversible perfusion defects on 201TI-SPECT, mild- (SDS: 2-4), moderate- (SDS: 5-8), and severe- (SDS>8) perfusion defects were also identified by GRE-MRI perfusion analysis in 75% (6/8), in 56% (9/16) and 100% (6/6), respectively. Conclusions: GRE-MRI first-pass stress perfusion imaging may not identify up to 30% of mild-to-moderate perfusion defects in a group of preselected patients with predominantly known CAD and abnormal 201TI-SPECT studie

    Family Unification, Exotic States and Light Magnetic Monopoles

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    Models with fermions in bifundamental representations can lead naturally to family unification as opposed to family replication. Such models typically predict (exotic) color singlet states with fractional electric charge, and magnetic monopoles with multiple Dirac charge. The exotics may be at the TeV scale, and relatively light magnetic monopoles (greater than about 10^7 GeV) can be present in the galaxy with abundance near the Parker bound. We focus on three family SU(4)XSU(3)XSU(3) models.Comment: 37 page

    Improvement in coronary circulatory function in morbidly obese individuals after gastric bypass-induced weight loss: relation to alterations in endocannabinoids and adipocytokines

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    Aims To investigate the effect of surgical gastric bypass-induced weight loss and related alterations in endocannabinoids (ECs) and adipocytokine plasma levels on coronary circulatory dysfunction in morbidly obese (MOB) individuals. Methods and results Myocardial blood flow (MBF) responses to cold pressor test (CPT) from rest (ΔMBF) and during pharmacologically induced hyperaemia were measured with 13N-ammonia PET/CT in 18 MOB individuals with a body mass index (BMI) > 40 kg/m2 at baseline and after a median follow-up period of 22 months. Gastric bypass intervention decreased BMI from a median of 44.8 (inter-quartile range: 43.3, 48.2) to 30.8 (27.3, 34.7) kg/m2 (P < 0.0001). This decrease in BMI was accompanied by a marked improvement in endothelium-related ΔMBF to CPT and hyperaemic MBFs, respectively [0.34 (0.18, 0.41) from 0.03 (−0.08, 0.15) mL/g/min, P = 0.002; and 2.51 (2.17, 2.64) from 1.53 (1.39, 2.18) mL/g/min, P < 0.001]. There was an inverse correlation between decreases in plasma concentrations of the EC anandamide and improvement in ΔMBF to CPT (r = −0.59, P = 0.009), while increases in adiponectin plasma levels correlated positively with hyperaemic MBFs (r = 0.60, P = 0.050). Conversely, decreases in leptin plasma concentrations were not observed to correlate with the improvement in coronary circulatory function (r = 0.22, P = 0.400, and r = −0.31, P = 0.250). Conclusions Gastric bypass-related reduction of BMI in MOB individuals beneficially affects coronary circulatory dysfunction. The dysbalance between ECs and adipocytokines appears to be an important determinant of coronary circulatory function in obesit

    Analyzing Chromosomes, Ion Channels and Novel Nucleic Acid Structures by AFM

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    The atomic force microscope (AFM) is proving to be a powerful tool for analysis of biological samples. We provide three examples of the application of AFM to the study of biological questions. First, polytene chromosomes from Drosophila are imaged and manipulated by the AFM. Second, the localization of calcium channels on the release face of a nerve terminal is described. Finally, analyses of a new form of DNA, the G-wire, is presented. These examples illustrate the wide variety of biological questions to which AFM can contribute

    Matching between regional coronary vasodilator capacity and corresponding circumferential strain in individuals with normal and increasing body weight

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    Background: To define the relationship between regional coronary vasodilator capacity and myocardial circumferential strain at rest in normal weight, overweight, and obese individuals with normal global left-ventricular function. Methods and Results: Myocardial blood flow at rest and during pharmacologic vasodilation was measured with 13N-ammonia PET/CT in mL/g/minute in normal weight control (CON, n=12), overweight (OW, n=10), and obese individuals (OB, n=10). In addition, resting myocardial function was evaluated as circumferential strain (Єc, %) by MRI. Global myocardial flow reserve (MFR) did not differ significantly between CON and OW (2.98±0.96 vs 2.70±0.66, P=.290), whereas it declined significantly in OB (1.98±1.04, P=.030). Further, global Єc (%) was comparable between CON, OW, and OB (−0.24±0.03, −0.23±0.02, and −0.23±0.04) but it was lowest in OB when normalized to the rate-pressure product (NЄc: −0.31±0.06, −0.32±0.05, and −0.26±0.08). When MFR of the three major coronary territories was correlated with corresponding Єc, a positive association was observed in CON (r=0.36, P=.030), in OW (r=0.54, P=.002), and also in OB when relating NЄc to coronary vascular resistance during pharmacologic vasodilation (r=−0.46, P=.010). Conclusions: Higher coronary vasodilator capacity is related to corresponding regional circumferential strain at rest in non-obese individuals, while this is also observed for reduced MFR in obesit
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