350 research outputs found

    Multilinear Wavelets: A Statistical Shape Space for Human Faces

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    We present a statistical model for 33D human faces in varying expression, which decomposes the surface of the face using a wavelet transform, and learns many localized, decorrelated multilinear models on the resulting coefficients. Using this model we are able to reconstruct faces from noisy and occluded 33D face scans, and facial motion sequences. Accurate reconstruction of face shape is important for applications such as tele-presence and gaming. The localized and multi-scale nature of our model allows for recovery of fine-scale detail while retaining robustness to severe noise and occlusion, and is computationally efficient and scalable. We validate these properties experimentally on challenging data in the form of static scans and motion sequences. We show that in comparison to a global multilinear model, our model better preserves fine detail and is computationally faster, while in comparison to a localized PCA model, our model better handles variation in expression, is faster, and allows us to fix identity parameters for a given subject.Comment: 10 pages, 7 figures; accepted to ECCV 201

    Fragmentation and systematics of the Pygmy Dipole Resonance in the stable N=82 isotones

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    The low-lying electric dipole (E1) strength in the semi-magic nucleus 136Xe has been measured which finalizes the systematic survey to investigate the so-called pygmy dipole resonance (PDR) in all stable even N=82 isotones with the method of nuclear resonance fluorescence using real photons in the entrance channel. In all cases, a fragmented resonance-like structure of E1 strength is observed in the energy region 5 MeV to 8 MeV. An analysis of the fragmentation of the strength reveals that the degree of fragmentation decreases towards the proton-deficient isotones while the total integrated strength increases indicating a dependence of the total strength on the neutron-to-proton ratio. The experimental results are compared to microscopic calculations within the quasi-particle phonon model (QPM). The calculation includes complex configurations of up to three phonons and is able to reproduce also the fragmentation of the E1 strength which allows to draw conclusions on the damping of the PDR. Calculations and experimental data are in good agreement in the degree of fragmentation and also in the integrated strength if the sensitivity limit of the experiments is taken into account

    3D Face Reconstruction from Light Field Images: A Model-free Approach

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    Reconstructing 3D facial geometry from a single RGB image has recently instigated wide research interest. However, it is still an ill-posed problem and most methods rely on prior models hence undermining the accuracy of the recovered 3D faces. In this paper, we exploit the Epipolar Plane Images (EPI) obtained from light field cameras and learn CNN models that recover horizontal and vertical 3D facial curves from the respective horizontal and vertical EPIs. Our 3D face reconstruction network (FaceLFnet) comprises a densely connected architecture to learn accurate 3D facial curves from low resolution EPIs. To train the proposed FaceLFnets from scratch, we synthesize photo-realistic light field images from 3D facial scans. The curve by curve 3D face estimation approach allows the networks to learn from only 14K images of 80 identities, which still comprises over 11 Million EPIs/curves. The estimated facial curves are merged into a single pointcloud to which a surface is fitted to get the final 3D face. Our method is model-free, requires only a few training samples to learn FaceLFnet and can reconstruct 3D faces with high accuracy from single light field images under varying poses, expressions and lighting conditions. Comparison on the BU-3DFE and BU-4DFE datasets show that our method reduces reconstruction errors by over 20% compared to recent state of the art

    Investigation of octupole vibrational states in 150Nd via inelastic proton scattering (p,p'g)

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    Octupole vibrational states were studied in the nucleus 150Nd^{150}\mathrm{Nd} via inelastic proton scattering with \unit[10.9]{MeV} protons which are an excellent probe to excite natural parity states. For the first time in 150Nd^{150}\mathrm{Nd}, both the scattered protons and the γ\gamma rays were detected in coincidence giving the possibility to measure branching ratios in detail. Using the coincidence technique, the B(E1)B(E1) ratios of the decaying transitions for 10 octupole vibrational states and other negative-parity states to the yrast band were determined and compared to the Alaga rule. The positive and negative-parity states revealed by this experiment are compared with Interacting Boson Approximation (IBA) calculations performed in the (spdf) boson space. The calculations are found to be in good agreement with the experimental data, both for positive and negative-parity states

    The electric dipole response of 76^{76}Se above 4 MeV

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    The dipole response of 3476^{76}_{34}Se in the energy range 4 to 9 MeV has been analyzed using a (γ,γ)(\vec\gamma,{\gamma}') polarized photon scattering technique, performed at the High Intensity γ\gamma-Ray Source facility, to complement previous work performed using unpolarized photons. The results of this work offer both an enhanced sensitivity scan of the dipole response and an unambiguous determination of the parities of the observed J=1 states. The dipole response is found to be dominated by E1E1 excitations, and can reasonably be attributed to a pygmy dipole resonance. Evidence is presented to suggest that a significant amount of directly unobserved excitation strength is present in the region, due to unobserved branching transitions in the decays of resonantly excited states. The dipole response of the region is underestimated when considering only ground state decay branches. We investigate the electric dipole response theoretically, performing calculations in a 3D cartesian-basis time-dependent Skyrme-Hartree-Fock framework.Comment: 20 pages, 18 figures, to be submitted to PR

    A New Method of Probing the Phonon Mechanism in Superconductors including MgB2_{2}

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    Weak localization has a strong influence on both the normal and superconducting properties of metals. In particular, since weak localization leads to the decoupling of electrons and phonons, the temperature dependence of resistance (i.e., λtr\lambda_{tr}) is decreasing with increasing disorder, as manifested by Mooij's empirical rule. In addition, Testardi's universal correlation of TcT_{c} (i.e., λ\lambda) and the resistance ratio (i.e., λtr\lambda_{tr}) follows. This understanding provides a new means to probe the phonon mechanism in superconductors including MgB2_{2}. The merits of this method are its applicability to any superconductors and its reliability because the McMillan's electron-phonon coupling constant λ\lambda and λtr\lambda_{tr} change in a broad range, from finite values to zero, due to weak localization. Karkin et al's preliminary data of irradiated MgB2_{2} show the Testardi correlation, indicating that the dominant pairing mechanism in MgB2_{2} is the phonon-mediated interaction.Comment: 9 pages, latex, 3 figure

    ACTA OTORHINOLARYNGOLOGICA ITALICA

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    Lobiettivo del presente studio è stato determinare se i livelli plasmatici dei prodotti avanzati di ossidazione proteica (AOPP) rappresentino dei marker di stress ossidativo nei pazienti pediatrici affetti da tonsillite cronica. Per lo studio sono stati arruolati, presso i Dipartimenti di Otorinolaringoiatria e Chirurgia pediatrica dellOspedale Universitario di Dumlupinar, trenta bambini sani e trenta affetti da tonsillite cronica. Il gruppo dei pazienti affetti da malattia è stato sottoposto a un prelievo ematico preoperatorio e ad una biopsia intraoperatoria del tessuto tonsillare. Il gruppo dei pazienti sani è stato sottoposto unicamente al prelievo ematico. I livelli plasmatici e tissutali degli AOPP sono quindi stati misurati mediante spettrofotometria. I livelli sierici degli AOPP sono risultati essere più elevati nel gruppo dei pazienti affetti da tonsillite cronica (13,1 ± 3,3 ng/ml) rispetto al gruppo di controllo (11,6 ± 2,3 ng/ml; P < 0,05). Il livello tissutale medio degli AOPP nei pazienti malati è risultato essere superiore a quello plasmatico medio sia nel gruppo dei pazienti sani che in quello dei pazienti malati (41,9 ± 13,5 ng/mg; P < 0,05). I livelli plasmatici e tissutali degli AOPP sono risultati quindi essere più elevati nei pazienti malati rispetto al gruppo di controllo. Gli AOPP potrebbero quindi rappresentare una nuova classe di molecole pro-infiammatorie coinvolte nello stress ossidativo nella tonsillite cronica e potrebbero avere un ruolo come marker di stress ossidativo nei pazienti pediatrici affetti da tale patologia

    Approaching the Gamow Window with Stored Ions : Direct Measurement of Xe 124 (p,γ) in the ESR Storage Ring

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    © 2019 American Physical Society. All rights reserved.We report the first measurement of low-energy proton-capture cross sections of Xe124 in a heavy-ion storage ring. Xe12454+ ions of five different beam energies between 5.5 and 8 AMeV were stored to collide with a windowless hydrogen target. The Cs125 reaction products were directly detected. The interaction energies are located on the high energy tail of the Gamow window for hot, explosive scenarios such as supernovae and x-ray binaries. The results serve as an important test of predicted astrophysical reaction rates in this mass range. Good agreement in the prediction of the astrophysically important proton width at low energy is found, with only a 30% difference between measurement and theory. Larger deviations are found above the neutron emission threshold, where also neutron and γ widths significantly impact the cross sections. The newly established experimental method is a very powerful tool to investigate nuclear reactions on rare ion beams at low center-of-mass energies.Peer reviewedFinal Published versio

    Dipole Strength Distributions from HIGS Experiments

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    A series of photon scattering experiments has been performed on the double-beta decay partners 76Ge and 76Se, in order to investigate their dipole response up to the neutron separation threshold. Gamma-ray beams from bremsstrahlung at the S-DALINAC and from Compton-backscattering at HIGS have been used to measure absolute cross sections and parities of dipole excited states, respectively. The HIGS data allows for indirect measurement of averaged branching ratios, which leads to significant corrections in the observed excitation cross sections. Results are compared to statistical calculations, to test photon strength functions and the Axel-Brink hypothesi

    The high-efficiency {\gamma}-ray spectroscopy setup {\gamma}3 at HI{\gamma}S

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    The existing Nuclear Resonance Fluorescence (NRF) setup at the HI{\gamma}S facility at the Triangle Universities Nuclear Laboratory at Duke University has been extended in order to perform {\gamma}-{\gamma} coincidence experiments. The new setup combines large volume LaBr3:Ce detectors and high resolution HPGe detectors in a very close geometry to offer high efficiency, high energy resolution as well as high count rate capabilities at the same time. The combination of a highly efficient {\gamma}-ray spectroscopy setup with the mono-energetic high-intensity photon beam of HI{\gamma}S provides a worldwide unique experimental facility to investigate the {\gamma}-decay pattern of dipole excitations in atomic nuclei. The performance of the new setup has been assessed by studying the nucleus \sulfur at 8.125 MeV beam energy. The {\gamma}-decay branching ratio from the 1+1^+ level at 8125.4 keV to the first excited 2+2^+ state was determined to 15.7(3)%.Comment: 9 pages, 11 figure
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