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Author |
Blume, M.; Martinez-Moller, A.; Keil, A.; Navab, N.; Rafecas, M. |
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Title |
Joint Reconstruction of Image and Motion in Gated Positron Emission Tomography |
Type |
Journal Article |
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Year |
2010 |
Publication |
IEEE Transactions on Medical Imaging |
Abbreviated Journal |
IEEE Trans. Med. Imaging |
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Volume |
29 |
Issue |
11 |
Pages |
1892-1906 |
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Keywords |
Gating; motion compensation; positron emission tomography (PET); reconstruction |
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Abstract |
We present a novel intrinsic method for joint reconstruction of both image and motion in positron emission tomography (PET). Intrinsic motion compensation methods exclusively work on the measured data, without any external motion measurements. Most of these methods separate image from motion estimation: They use deformable image registration/optical flow techniques in order to estimate the motion from individually reconstructed gates. Then, the image is estimated based on this motion information. With these methods, a main problem lies in the motion estimation step, which is based on the noisy gated frames. The more noise is present, the more inaccurate the image registration becomes. As we show both visually and quantitatively, joint reconstruction using a simple deformation field motion model can compete with state-of-the-art image registration methods which use robust multilevel B-spline motion models. |
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Address |
[Blume, Moritz; Rafecas, Magdalena] Univ Valencia, CSIC, IFIC, E-46071 Valencia, Spain, Email: moritz.blume@cs.tum.edu |
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Ieee-Inst Electrical Electronics Engineers Inc |
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English |
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ISSN |
0278-0062 |
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Conference |
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Notes |
ISI:000283941800007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial  |
340 |
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Author |
Carbone, C.; Mena, O.; Verde, L. |
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Title |
Cosmological parameters degeneracies and non-Gaussian halo bias |
Type |
Journal Article |
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Year |
2010 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
07 |
Issue |
7 |
Pages |
020 - 17pp |
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Keywords |
power spectrum; redshift surveys; galaxy clusters; cosmological parameters from LSS |
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Abstract |
We study the impact of the cosmological parameters uncertainties on the measurements of primordial non-Gaussianity through the large-scale non-Gaussian halo bias effect. While this is not expected to be an issue for the standard Lambda CDM model, it may not be the case for more general models that modify the large-scale shape of the power spectrum. We consider the so-called local non-Gaussianity model, parametrized by the f(NL) non-Gaussianity parameter which is zero for a Gaussian case, and make forecasts on f(NL) from planned surveys, alone and combined with a Planck CMB prior. In particular, we consider EUCLID- and LSST-like surveys and forecast the correlations among f(NL) and the running of the spectral index alpha(s), the dark energy equation of state w, the effective sound speed of dark energy perturbations c(s)(2), the total mass of massive neutrinos M-nu = Sigma m(nu), and the number of extra relativistic degrees of freedom N-nu(rel). Neglecting CMB information on f(NL) and scales k > 0.03h/Mpc, we find that, if N-nu(rel) is assumed to be known, the uncertainty on cosmological parameters increases the error on f(NL) by 10 to 30% depending on the survey. Thus the f(NL) constraint is remarkable robust to cosmological model uncertainties. On the other hand, if N-nu(rel) is simultaneously constrained from the data, the f(NL) error increases by similar to 80%. Finally, future surveys which provide a large sample of galaxies or galaxy clusters over a volume comparable to the Hubble volume can measure primordial non-Gaussianity of the local form with a marginalized 1-sigma error of the order Delta f(NL) similar to 2 – 5, after combination with CMB priors for the remaining cosmological parameters. These results are competitive with CMB bispectrum constraints achievable with an ideal CMB experiment. |
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Address |
[Carbone, Carmelita] Univ Bologna, Dipartimento Astron, I-40127 Bologna, Italy, Email: carmelita.carbone@unibo.it |
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Iop Publishing Ltd |
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English |
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ISSN |
1475-7516 |
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Expedition |
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Conference |
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Notes |
ISI:000283573200010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
347 |
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Author |
Belver, D.; Cabanelas, P.; Castro, E.; Garzon, J.A.; Gil, A.; Gonzalez-Diaz, D.; Koenig, W.; Traxler, M. |
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Title |
Performance of the Low-Jitter High-Gain/Bandwidth Front-End Electronics of the HADES tRPC Wall |
Type |
Journal Article |
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Year |
2010 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
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Volume |
57 |
Issue |
5 |
Pages |
2848-2856 |
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Keywords |
Charge to width algorithm; fast amplifying and digitizing electronics; front-end electronics; HADES; time of flight; timing RPC |
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Abstract |
A front-end electronics (FEE) chain for accurate time measurements has been developed for the new Resistive Plate Chamber (RPC)-based Time-of-Flight (TOF) wall of the High Acceptance Di-Electron Spectrometer (HADES). The wall covers an area of around 8 m(2) divided in 6 sectors. In total, 1122 4-gap timing RPC cells are read-out by 2244 time and charge sensitive channels. The FEE chain consists of 2 custom-made boards: a 4-channel Daughter BOard(DBO) and a 32-channel MotherBOard (MBO). The DBO uses a fast 2 GHz amplifier feeding a dual high-speed discriminator. The time and charge information are encoded, respectively, in the leading edge and the width of an LVDS signal. Each MBO houses up to 8 DBOs providing them regulated voltage supply, threshold values via DACs, test signals and, additionally, routing out a signal proportional to the channel multiplicity needed for a 1st level trigger decision. The MBO delivers LVDS signals to a multi-purpose Trigger Readout Board (TRB) for data acquisition. The FEE allows achieving a system resolution around 75 ps fulfilling comfortably the requirements of the HADES upgrade [1]. The commissioning of the whole RPC wall is finished and the 6 sectors are already mounted in their final position in the HADES spectrometer and ready to take data during the beam-times foreseen for 2010. |
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Address |
[Belver, Daniel; Cabanelas, P.; Castro, E.; Garzon, J. A.] Univ Santiago Compostela, LabCAF, Santiago De Compostela 15782, Spain, Email: daniel.belver@usc.es |
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Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
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Language |
English |
Summary Language |
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ISSN |
0018-9499 |
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Conference |
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Notes |
ISI:000283440400007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
349 |
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Author |
ANTARES Collaboration (Aguilar, J.A. et al); Bigongiari, C.; Dornic, D.; Emanuele, U.; Gomez-Gonzalez, J.P.; Hernandez-Rey, J.J.; Mangano, S.; Salesa, F.; Toscano, S.; Yepes, H.; Zornoza, J.D.; Zuñiga, J. |
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Title |
Performance of the front-end electronics of the ANTARES neutrino telescope |
Type |
Journal Article |
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Year |
2010 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
622 |
Issue |
1 |
Pages |
59-73 |
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Keywords |
Neutrino telescope; Photomultiplier tube; Front-end electronics; ASIC |
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Abstract |
ANTARES is a high-energy neutrino telescope installed in the Mediterranean Sea at a depth of 2475 m. It consists of a three-dimensional array of optical modules, each containing a large photomultiplier tube. A total of 2700 front-end ASICs named analogue ring samplers (ARS) process the phototube signals, measure their arrival time, amplitude and shape as well as perform monitoring and calibration tasks. The ARS chip processes the analogue signals from the optical modules and converts information into digital data. All the information is transmitted to shore through further multiplexing electronics and an optical link. This paper describes the performance of the ARS chip: results from the functionality and characterization tests in the laboratory are summarized and the long-term performance in the apparatus is illustrated. |
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Address |
[Aguilar, J. A.; Bigongiari, C.; Dornic, D.; Emanuele, U.; Gomez-Gonzalez, J. P.; Hernandez-Rey, J. J.; Mangano, S.; Salesa, F.; Toscano, S.; Yepes, H.; Zornoza, J. D.; Zuniga, J.] Univ Valencia, IFIC, CSIC, Valencia 46071, Spain, Email: s.loucatos@cea.fr |
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Corporate Author |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-9002 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000282530300009 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
363 |
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Author |
Horvat, S.; Magas, V.K.; Strottman, D.D.; Csernai, L.P. |
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Title |
Entropy development in ideal relativistic fluid dynamics with the Bag Model equation of state |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
692 |
Issue |
4 |
Pages |
277-280 |
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Keywords |
Quark deconfinement; Quark-gluon plasma production; Phase transitions; Relativistic heavy-ion collisions; Hydrodynamic models |
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Abstract |
We consider an idealized situation where the Quark-Gluon Plasma (QGP) is described by a perfect, (3 + 1)-dimensional fluid dynamic model starting from an initial state and expanding until a final state where freeze-out and/or hadronization takes place. We study the entropy production with attention to effects of (i) numerical viscosity, (ii) late stages of flow where the Bag Constant and the partonic pressure are becoming similar, (iii) and the consequences of final freeze-out and constituent quark matter formation. |
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Address |
[Horvat, Sz; Csernai, L. P.] Univ Bergen, Inst Phys & Technol, N-5007 Bergen, Norway, Email: szhorvat@ift.uib.no |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000282249400011 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
375 |
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| Permanent link to this record |
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Author |
Aguilar, A.C.; Binosi, D.; Papavassiliou, J. |
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Title |
QCD effective charges from lattice data |
Type |
Journal Article |
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Year |
2010 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
07 |
Issue |
7 |
Pages |
002 - 24pp |
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Keywords |
Nonperturbative Effects; QCD |
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Abstract |
We use recent lattice data on the gluon and ghost propagators, as well as the Kugo-Ojima function, in order to extract the non-perturbative behavior of two particular definitions of the QCD effective charge, one based on the pinch technique construction, and one obtained from the standard ghost-gluon vertex. The construction relies crucially on the definition of two dimensionful quantities, which are invariant under the renormalization group, and are built out of very particular combinations of the aforementioned Green's functions. The main non-perturbative feature of both effective charges, encoded in the infrared finiteness of the gluon propagator and ghost dressing function used in their definition, is the freezing at a common finite (non-vanishing) value, in agreement with a plethora of theoretical and phenomenological expectations. We discuss the sizable discrepancy between the freezing values obtained from the present lattice analysis and the corresponding estimates derived from several phenomenological studies, and attribute its origin to the difference in the gauges employed. A particular toy calculation suggests that the modifications induced to the non-perturbative gluon propagator by the gauge choice may indeed account for the observed deviation of the freezing values. |
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Address |
[Aguilar, A. C.] Fed Univ ABC, CCNH, BR-09210170 Santo Andre, Brazil, Email: arlene.aguilar@ufabc.edu.br |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1126-6708 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000281504500002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
384 |
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Author |
Rodriguez-Alvarez, M.J.; Sanchez, F.; Soriano, A.; Iborra, A. |
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Title |
Sparse Givens resolution of large system of linear equations: Applications to image reconstruction |
Type |
Journal Article |
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Year |
2010 |
Publication |
Mathematical and Computer Modelling |
Abbreviated Journal |
Math. Comput. Model. |
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Volume |
52 |
Issue |
7-8 |
Pages |
1258-1264 |
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Keywords |
Givens rotations; QR-factorization; Computed tomography; Image reconstruction |
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Abstract |
In medicine, computed tomographic images are reconstructed from a large number of measurements of X-ray transmission through the patient (projection data). The mathematical model used to describe a computed tomography device is a large system of linear equations of the form AX = B. In this paper we propose the QR decomposition as a direct method to solve the linear system. QR decomposition can be a large computational procedure. However, once it has been calculated for a specific system, matrices Q and R are stored and used for any acquired projection on that system. Implementation of the QR decomposition in order to take more advantage of the sparsity of the system matrix is discussed. |
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Address |
[Rodriguez-Alvarez, Maria-Jose; Iborra, Amadeo] Univ Politecn Valencia, Inst Matemat Multidisciplinar, E-46022 Valencia, Spain, Email: mjrodri@imm.upv.es |
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Corporate Author |
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Thesis |
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Publisher |
Pergamon-Elsevier Science Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0895-7177 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000280933700043 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
395 |
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| Permanent link to this record |
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Author |
Pierre Auger Collaboration (Abraham, J. et al); Pastor, S. |
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Title |
The fluorescence detector of the Pierre Auger Observatory |
Type |
Journal Article |
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Year |
2010 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
620 |
Issue |
2-3 |
Pages |
227-251 |
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Keywords |
Cosmic rays; Fluorescence detector |
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Abstract |
The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions. |
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Address |
[Bohacova, M.; Chudoba, J.; Grygar, J.; Hrabovsky, M.; Karova, T.; Mandat, D.; Necesal, P.; Nozka, L.; Nyklicek, M.; Palatka, M.; Pech, M.; Prouza, M.; Ridky, J.; Schovancova, J.; Schovanek, P.; Travnicek, P.] Acad Sci Czech Republic, Inst Phys, Prague, Czech Republic, Email: prouza@fzu.cz |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-9002 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000280601700018 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
400 |
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Author |
Yamagata-Sekihara, J.; Oset, E. |
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Title |
V P gamma radiative decay of resonances dynamically generated from the vector meson-vector meson interaction |
Type |
Journal Article |
| |
Year |
2010 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
690 |
Issue |
4 |
Pages |
376-381 |
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Keywords |
Local hidden gauge; Radiative decays; Vector mesons; Dynamically generated resonances |
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Abstract |
We evaluate the radiative decay into a vector, a pseudoscalar and a photon of several resonances dynamically generated from the vector-vector interaction. The process proceeds via the decay of one of the vector components into a pseudoscalar and a photon, which have an invariant mass distribution very different from phase space as a consequence of the two vector structure of the resonances. Experimental work along these lines should provide useful information on the nature of these resonances. |
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Address |
[Yamagata-Sekihara, J.] Univ Valencia, Ctr Mixto, CSIC, Inst Invest Paterna,Dept Fis Teor, Valencia 46071, Spain, Email: yamagata@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000279835300008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
408 |
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| Permanent link to this record |
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Author |
Jimenez, R.; Kitching, T.; Pena-Garay, C.; Verde, L. |
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Title |
Can we measure the neutrino mass hierarchy in the sky? |
Type |
Journal Article |
| |
Year |
2010 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
05 |
Issue |
5 |
Pages |
035 - 14pp |
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Keywords |
cosmological neutrinos; neutrino masses from cosmology; power spectrum; gravitational lensing |
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Abstract |
Cosmological probes are steadily reducing the total neutrino mass window, resulting in constraints on the neutrino-mass degeneracy as the most significant outcome. In this work we explore the discovery potential of cosmological probes to constrain the neutrino hierarchy, and point out some subtleties that could yield spurious claims of detection. This has an important implication for next generation of double beta decay experiments, that will be able to achieve a positive signal in the case of degenerate or inverted hierarchy of Majorana neutrinos. We find that cosmological experiments that nearly cover the whole sky could in principle distinguish the neutrino hierarchy by yielding 'substantial' evidence for one scenario over the another, via precise measurements of the shape of the matter power spectrum from large scale structure and weak gravitational lensing. |
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Address |
[Jimenez, Raul; Verde, Licia] Univ Barcelona, ICREA, E-08028 Barcelona, Spain, Email: raul.jimenez@icc.ub.edu |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1475-7516 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000279490800005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
418 |
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| Permanent link to this record |
