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Author Pino, F.; Roe, N.; Orero, A.; Falcon, C.; Rojas, S.; Benlloch, J.M.; Ros, D.; Pavia, J. doi  openurl
  Title Development of a variable-radius pinhole SPECT system with a portable gamma camera Type Journal Article
  Year 2011 Publication Revista Española de Medicina Nuclear Abbreviated Journal Rev. Esp. Med. Nucl.  
  Volume 30 Issue 5 Pages 286-291  
  Keywords SPECT; Small animal; Pinhole; Portable gamma camera; Continuous scintillator  
  Abstract Objective: To develop a small-animal SPECT system using a low cost commercial portable gamma camera equipped with a pinhole collimator, a continuous scintillation crystal and a position-sensitive photomultiplier tube. Material and methods: The gamma camera was attached to a variable radius system, which enabled us to optimize sensitivity and resolution by adjusting the radius of rotation to the size of the object. To investigate the capability of the SPECT system for small animal imaging, the dependence of resolution and calibration parameters on radius was assessed and acquisitions of small phantoms and mice were carried out. Results: Resolution values, ranging from 1.0 mm for a radius of 21.4 mm and 1.4 mm for a radius of 37.2 mm were obtained, thereby justifying the interest of a variable radius SPECT system. Conclusions: The image quality of phantoms and animals were satisfactory, thus confirming the usefulness of the system for small animal SPECT imaging.  
  Address [Pino, F; Roe, N; Ros, D] Univ Barcelona, Fac Med, Unitat Biofis, Barcelona 7, Spain, Email: fpino@iconcologia.net  
  Corporate Author Thesis  
  Publisher Elsevier Science Inc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0212-6982 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000294659400004 Approved no  
  Is ISI yes International Collaboration (up) no  
  Call Number IFIC @ elepoucu @ Serial 753  
Permanent link to this record
 

 
Author Galli, P.; Ortin, T.; Perz, J.; Shahbazi, C.S. url  doi
openurl 
  Title Non-extremal black holes of N=2, d=4 supergravity Type Journal Article
  Year 2011 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 07 Issue 7 Pages 041  
  Keywords  
  Abstract We propose a generic recipe for deforming extremal black holes into nonextremal black holes and we use it to find and study the static non-extremal black-hole solutions of several N = 2, d = 4 supergravity models (SL(2, R)/U(1), (CP) over bar (n) and STU with four charges). In all the cases considered, the non-extremal family of solutions smoothly interpolates between all the different extremal limits, supersymmetric and not supersymmetric. This fact can be used to explicitly find extremal non-supersymmetric solutions also in the cases in which the attractor mechanism does not completely fix the values of the scalars on the event horizon and they still depend on the boundary conditions at spatial infinity. We compare (supersymmetry) Bogomol'nyi bounds with extremality bounds, we find the first-order flow equations for the non-extremal solutions and the corresponding superpotential, which gives in the different extremal limits different superpotentials for extremal black holes. We also compute the entropies (areas) of the inner (Cauchy) and outer (event) horizons, finding in all cases that their product gives the square of the moduli-independent entropy of the extremal solution with the same electric and magnetic charges.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1126-6708 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000293741400041 Approved no  
  Is ISI yes International Collaboration (up) no  
  Call Number IFIC @ elepoucu @ Serial 761  
Permanent link to this record
 

 
Author Panotopoulos, G.; Tuzon, P. url  doi
openurl 
  Title The physics of a new gauge boson in a Stueckelberg extension of the two-Higgs-doublet model Type Journal Article
  Year 2011 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 07 Issue 7 Pages 039  
  Keywords  
  Abstract String theory constructions using D-brane physics offer a framework where ingredients like extra abelian factors in the gauge group, more than one Higgs doublet and a generalized Green-Schwarz mechanism appear at the same time. Motivated by works towards the direction of obtaining the Standard Model in orientifold constructions, we study in the present work a Stueckelberg extension of the two-Higgs-doublet model. The distinctive features of our model are i) a sharp decay width for the heavy gauge boson, and ii) a charged Higgs boson having two main decay channels at tree level with equal branching ratios.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1126-6708 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000293741400039 Approved no  
  Is ISI yes International Collaboration (up) no  
  Call Number IFIC @ elepoucu @ Serial 763  
Permanent link to this record
 

 
Author Bernabeu, J.; Espriu, D.; Puigdomenech, D. url  doi
openurl 
  Title Gravitational waves in the presence of a cosmological constant Type Journal Article
  Year 2011 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 84 Issue 6 Pages 063523 - 13pp  
  Keywords  
  Abstract We derive the effects of a nonzero cosmological constant Lambda on gravitational wave propagation in the linearized approximation of general relativity. In this approximation, we consider the situation where the metric can be written as g(mu nu) = eta(mu nu) + h(mu nu)(Lambda) + h(mu nu)(W), h(mu nu)(Lambda,W) << 1, where h(mu nu)(Lambda) is the background perturbation and h(mu nu)(W) is a modification interpretable as a gravitational wave. For Lambda not equal 0, this linearization of Einstein equations is self-consistent only in certain coordinate systems. The cosmological Friedmann-Robertson-Walker coordinates do not belong to this class and the derived linearized solutions have to be reinterpreted in a coordinate system that is homogeneous and isotropic to make contact with observations. Plane waves in the linear theory acquire modifications of order root Lambda, both in the amplitude and the phase, when considered in Friedmann-Robertson-Walker coordinates. In the linearization process for h(mu nu), we have also included terms of order O(Lambda h(mu nu)). For the background perturbation h(mu nu)(Lambda), the difference is very small, but when the term h(mu nu)(W)Lambda is retained the equations of motion can be interpreted as describing massive spin-2 particles. However, the extra degrees of freedom can be approximately gauged away, coupling to matter sources with a strength proportional to the cosmological constant itself. Finally, we discuss the viability of detecting the modifications caused by the cosmological constant on the amplitude and phase of gravitational waves. In some cases, the distortion with respect to gravitational waves propagating in Minkowski space-time is considerable. The effect of Lambda could have a detectable impact on pulsar timing arrays.  
  Address [Bernabeu, J] Univ Valencia, Dept Fis Teor IFIC, CSIC, E-46100 Valencia, Spain  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000295223100005 Approved no  
  Is ISI yes International Collaboration (up) no  
  Call Number IFIC @ elepoucu @ Serial 766  
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Author Moles-Valls, R. doi  openurl
  Title Alignment of the ATLAS Inner Detector with proton-proton collision data Type Journal Article
  Year 2011 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A  
  Volume 650 Issue 1 Pages 235-239  
  Keywords ATLAS; Inner detector; Tracking system; Alignment  
  Abstract ATLAS is a multipurpose experiment that records the products of the LHC collisions. In order to reconstruct the trajectories of the charged particles produced in these collisions. ATLAS has an internal tracking system made of silicon planar sensors (pixels and micro-strips) and drift-tube based detectors; both together, they constitute the ATLAS Inner Detector. The alignment of the ATLAS tracking system requires the determination of their almost 36,000 degrees-of-freedom (DOF) with high accuracy. Thus, the demanded precision for the alignment of the pixel and micro-strip sensors is below 10 μm. As alignment algorithms are based on the minimization of the track-hit residuals, a linear system with a large number of DOF has to be solved. The alignment results of the ATLAS tracker using data recorded during cosmic commissioning phases in 2008 and 2009 and the LHC start up run in 2009 will be presented. Moreover recent 7 TeV data collected during 2010 run have been used to study the detector performance. These studies reveal that the detector is aligned with a precision high enough to cope with the requirements.  
  Address [Moles-Valls, R] IFIC CSIC UV Valencia, Valencia, Spain, Email: Regina.Moles@ific.uv.es  
  Corporate Author Thesis  
  Publisher Elsevier Science Bv Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0168-9002 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000295106500050 Approved no  
  Is ISI yes International Collaboration (up) no  
  Call Number IFIC @ elepoucu @ Serial 767  
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