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Author Galli, P.; Ortin, T.; Perz, J.; Shahbazi, C.S.
Title From supersymmetric to non-supersymmetric black holes Type Journal Article
Year 2012 Publication Fortschritte der Physik-Progress of Physics Abbreviated Journal Fortschritte Phys.-Prog. Phys.
Volume 60 Issue 9-10 Pages 1026-1029
Keywords (up) Black holes; supergravity
Abstract Methods similar to those used for obtaining supersymmetric black hole solutions can be employed to find also non-supersymmetric solutions. We briefly review some of them, with the emphasis on the non-extremal deformation ansatz of [1].
Address [Ortin, Tomas; Perz, Jan; Shahbazi, C. S.] Inst Fis Teor UAM CSIC, Madrid 28049, Spain, Email: Pietro.Galli@ific.uv.es;
Corporate Author Thesis
Publisher Wiley-V C H Verlag Gmbh Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0015-8208 ISBN Medium
Area Expedition Conference
Notes WOS:000308301500012 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 1151
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Author Beltran Jimenez, J.; Heisenberg, L.; Olmo, G.J.; Rubiera-Garcia, D.
Title Born-Infeld inspired modifications of gravity Type Journal Article
Year 2018 Publication Physics Reports Abbreviated Journal Phys. Rep.
Volume 727 Issue Pages 1-129
Keywords (up) Born-Infeld gravity; Astrophysics; Black holes; Cosmology; Early universe; Compact objects; Singularities
Abstract General Relativity has shown an outstanding observational success in the scales where it has been directly tested. However, modifications have been intensively explored in the regimes where it seems either incomplete or signals its own limit of validity. In particular, the breakdown of unitarity near the Planck scale strongly suggests that General Relativity needs to be modified at high energies and quantum gravity effects are expected to be important. This is related to the existence of spacetime singularities when the solutions of General Relativity are extrapolated to regimes where curvatures are large. In this sense, Born-Infeld inspired modifications of gravity have shown an extraordinary ability to regularise the gravitational dynamics, leading to non-singular cosmologies and regular black hole spacetimes in a very robust manner and without resorting to quantum gravity effects. This has boosted the interest in these theories in applications to stellar structure, compact objects, inflationary scenarios, cosmological singularities, and black hole and wormhole physics, among others. We review the motivations, various formulations, and main results achieved within these theories, including their observational viability, and provide an overview of current open problems and future research opportunities.
Address [Beltran Jimenez, Jose] Univ Autonoma Madrid, CSIC, Inst Fis Teor, E-28049 Madrid, Spain, Email: jose.beltran@uam.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 0370-1573 ISBN Medium
Area Expedition Conference
Notes WOS:000425482900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3497
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Author Bazeia, D.; Losano, L.; Olmo, G.J.; Rubiera-Garcia, D.
Title Geodesically complete BTZ-type solutions of 2+1 Born-Infeld gravity Type Journal Article
Year 2017 Publication Classical and Quantum Gravity Abbreviated Journal Class. Quantum Gravity
Volume 34 Issue 4 Pages 045006 - 21pp
Keywords (up) Born-Infeld gravity; BTZ; wormholes; nonsingular solutions; geodesic completeness
Abstract We study Born-Infeld gravity coupled to a static, non-rotating electric field in 2 + 1 dimensions and find exact analytical solutions. Two families of such solutions represent geodesically complete, and hence nonsingular, spacetimes. Another family represents a point-like charge with a singularity at the center. Despite the absence of rotation, these solutions resemble the charged, rotating BTZ solution of general relativity but with a richer structure in terms of horizons. The nonsingular character of the first two families turn out to be attached to the emergence of a wormhole structure on their innermost region. This seems to be a generic prediction of extensions of general relativity formulated in metric-affine (or Palatini) spaces, where metric and connection are regarded as independent degrees of freedom.
Address [Bazeia, D.; Losano, L.; Olmo, Gonzalo J.] Univ Fed Paraiba, Dept Fis, BR-58051900 Joao Pessoa, Paraiba, Brazil, Email: bazeia@fisica.ufpb.br;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0264-9381 ISBN Medium
Area Expedition Conference
Notes WOS:000395398800002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3013
Permanent link to this record
 
 
Author Penalva, N.; Hernandez, E.; Nieves, J.
Title Visible energy and angular distributions of the charged particle from the tau-decay in b -> C tau (mu(nu)over-bar(mu)nu(tau), pi nu(tau), rho nu(tau))(nu)over-bar(tau) reactions Type Journal Article
Year 2022 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 04 Issue 4 Pages 026 - 25pp
Keywords (up) Bottom Quarks; Semi-Leptonic Decays; Flavour Symmetries; Left-Right Models
Abstract We study the d(2)Gamma(d)/(d omega d cos theta(d) ), d Gamma(d)/d cos theta(d) and d Gamma(d)/dE(d) distributions, which are defined in terms of the visible energy and polar angle of the charged particle from the tau-decay in b -> C tau (mu(nu) over bar (mu)nu(tau), pi nu(tau), rho nu(tau))(nu) over bar (tau), reactions. These differential decay widths could be measured in the near future with certain precision. The first two contain information on the transverse tau-spin, tau-angular and tau-angular-spin asymmetries of the H-b -> H-c tau(nu) over bar (tau) parent decay and, from a dynamical point of view, they are richer than the commonly used one, d(2)Gamma(d)/(d omega dE(d)), since the latter only depends on the tau longitudinal polarization. We pay attention to the deviations with respect to the predictions of the standard model (SM) for these new observables, considering new physics (NP) operators constructed using both right- and left-handed neutrino fields, within an effective field-theory approach. We present results for Lambda(b) -> Lambda(c)tau (mu(nu) over bar (mu)nu(tau), pi nu(tau), rho nu(tau))(nu) over bar (tau) and (B) over bar -> D-(*()) tau (mu(nu) over bar (mu)nu(tau), pi nu(tau), rho nu(tau))(nu) over bar (tau) sequential decays and discuss their use to disentangle between different NP models. In this respect, we show that d Gamma(d)/d cos theta(d) , which should be measured with sufficiently good statistics, becomes quite useful, especially in the tau -> pi nu(tau) mode. The study carried out in this work could be of special relevance due to the recent LHCb measurement of the lepton flavor universality ratio R Lambda(c) in agreement with the SM. The experiment identified the tau using its hadron decay into pi(-)pi(+)pi(-)nu(tau), and this result for R Lambda(c )which is in conflict with the phenomenology from the b-meson sector, needs confirmation from other tau reconstruction channels.
Address [Penalva, Neus; Nieves, Juan] Inst Fis Corpuscular Ctr Mixto CSIC UV, Inst Invest Paterna, C Catedrat Jose Beltran 2, E-46980 Valencia, Spain, Email: neuspe@ific.uv.es;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000781361300001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 5195
Permanent link to this record
 
 
Author Richart, J.; Otal, A.; Rodriguez, S.; Nicolas, A.I.; DePiaggio, M.; Santos, M.; Vijande, J.; Ballester, F.; Perez-Calatayud, J.
Title A practical MRI-based reconstruction method for a new endocavitary and interstitial gynaecological template Type Journal Article
Year 2015 Publication Journal of Contemporary Brachytherapy Abbreviated Journal J. Contemp. Brachytherapy
Volume 7 Issue 5 Pages 407-414
Keywords (up) brachytherapy template; catheter reconstruction; gynecological template; interstitial implants
Abstract Purpose: There are perineal templates for interstitial implants such as MUPIT and Syed applicators. Their limitations are the intracavitary component deficit and the necessity to use computed tomography (CT) for treatment planning since both applicators are non-magnetic resonance imaging (MRI) compatibles. To overcome these problems, a new template named Template Benidorm (TB) has been recently developed. Titanium needles are usually reconstructed based on their own artifacts, mainly in T1-weighted sequence, using the void on the tip as the needle tip position. Nevertheless, patient tissues surrounding the needles present heterogeneities that complicate the accurate identification of these artifact patterns. The purpose of this work is to improve the titanium needle reconstruction uncertainty for the TB case using a simple method based on the free needle lengths and typical MRI pellets markers. Material and methods: The proposed procedure consists on the inclusion of three small A-vitamin pellets (hyper-intense on MRI images) compressed by both applicator plates defining the central plane of the plate's arrangement. The needles used are typically 20 cm in length. For each needle, two points are selected defining the straight line. From such line and the plane equations, the intersection can be obtained, and using the free length (knowing the offset distance), the coordinates of the needle tip can be obtained. The method is applied in both T1W and T2W acquisition sequences. To evaluate the inter-observer variation of the method, three implants of T1W and another three of T2W have been reconstructed by two different medical physicists with experience on these reconstructions. Results and conclusions: The differences observed in the positioning were significantly smaller than 1 mm in all cases. The presented algorithm also allows the use of only T2W sequence either for contouring or reconstruction purposes. The proposed method is robust and independent of the visibility of the artifact at the tip of the needle.
Address [Richart, Jose; Otal, Antonio; Rodriguez, Silvia; DePiaggio, Marina; Santos, Manuel; Perez-Calatayud, Jose] Benidorm Hosp, Dept Radiotherapy, Alicante, Spain, Email: fballest@uv.es
Corporate Author Thesis
Publisher Termedia Publishing House Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1689-832x ISBN Medium
Area Expedition Conference
Notes WOS:000365247600012 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 2476
Permanent link to this record
 
 
Author Ballester, F.; Granero, D.; Perez-Calatayud, J.; Venselaar, J.L.M.; Rivard, M.J.
Title Study of encapsulated Tm-170 sources for their potential use in brachytherapy Type Journal Article
Year 2010 Publication Medical Physics Abbreviated Journal Med. Phys.
Volume 37 Issue 4 Pages 1629-1637
Keywords (up) brachytherapy; cancer; dosimetry; prosthetics; radioisotopes; thulium
Abstract Methods: The authors have assumed a theoretical Tm-170 cylindrical source encapsulated with stainless steel and typical dimensions taken from the currently available HDR Ir-192 brachytherapy sources. The dose-rate distribution was calculated for this source using the GEANT4 Monte Carlo (MC) code considering both photon and electron Tm-170 spectra. The AAPM TG-43 U1 brachytherapy dosimetry parameters were derived. To study general properties of Tm-170 encapsulated sources, spherical sources encapsulated with stainless steel and platinum were also studied. Moreover, the influence of small variations in the active core and capsule dimensions on the dosimetric characteristics was assessed. Treatment times required for a Tm-170 source were compared to those for Ir-192 and Yb-169 for the same contained activity. Results: Due to the energetic beta spectrum and the large electron yield, the bremsstrahlung contribution to the dose was of the same order of magnitude as from the emitted gammas and characteristic x rays. Moreover, the electron spectrum contribution to the dose was significant up to 4 mm from the source center compared to the photon contribution. The dose-rate constant Lambda of the cylindrical source was 1.23 cGy h(-1) U-1. The behavior of the radial dose function showed promise for applications in brachytherapy. Due to the electron spectrum, the anisotropy was large for r < 6 mm. Variations in manufacturing tolerances did not significantly influence the final dosimetry data when expressed in cGy h(-1) U-1. For typical capsule dimensions, maximum reference dose rates of about 0.2, 10, and 2 Gy min(-1) would then be obtained for Tm-170, Ir-192, and Yb-169, respectively, resulting in treatment times greater than those for HDR Ir-192 brachytherapy. Conclusions: The dosimetric characteristics of source designs exploiting the low photon energy of Tm-170 were studied for potential application in HDR-brachytherapy. Dose-rate distributions were obtained for cylindrical and simplified spherical Tm-170 source designs (stainless steel and platinum capsule materials) using MC calculations. Despite the high activity of Tm-170, calculated treatment times were much longer than for Ir-192.
Address [Ballester, Facundo] Univ Valencia, Dept Atom Mol & Nucl Phys, E-46100 Burjassot, Spain, Email: fballest@uv.es
Corporate Author Thesis
Publisher Amer Assoc Physicists Medicine Amer Inst Physics Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0094-2405 ISBN Medium
Area Expedition Conference
Notes ISI:000276211200027 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 478
Permanent link to this record
 
 
Author Beaulieu, L.; Ballester, F.; Granero, D.; Tedgren, A.C.; Haworth, A.; Lowenstein, J.R.; Ma, Y.Z.; Mourtada, F.; Papagiannis, P.; Rivard, M.J.; Siebert, F.A.; Sloboda, R.S.; Smith, R.L.; Thomson, R.M.; Verhaegen, F.; Fonseca, G.; Vijande, J.
Title AAPM WGDCAB Report 372: A joint AAPM, ESTRO, ABG, and ABS report on commissioning of model-based dose calculation algorithms in brachytherapy Type Journal Article
Year 2023 Publication Medical Physics Abbreviated Journal Med. Phys.
Volume 50 Issue 8 Pages e946–e960
Keywords (up) brachytherapy; commissioning; dose calculation; model-based dose calculation; Monte Carlo; TG-186
Abstract The introduction of model-based dose calculation algorithms (MBDCAs) in brachytherapy provides an opportunity for a more accurate dose calculation and opens the possibility for novel, innovative treatment modalities. The joint AAPM, ESTRO, and ABG Task Group 186 (TG-186) report provided guidance to early adopters. However, the commissioning aspect of these algorithms was described only in general terms with no quantitative goals. This report, from the Working Group on Model-Based Dose Calculation Algorithms in Brachytherapy, introduced a field-tested approach to MBDCA commissioning. It is based on a set of well-characterized test cases for which reference Monte Carlo (MC) and vendor-specific MBDCA dose distributions are available in a Digital Imaging and Communications in Medicine-Radiotherapy (DICOM-RT) format to the clinical users. The key elements of the TG-186 commissioning workflow are now described in detail, and quantitative goals are provided. This approach leverages the well-known Brachytherapy Source Registry jointly managed by the AAPM and the Imaging and Radiation Oncology Core (IROC) Houston Quality Assurance Center (with associated links at ESTRO) to provide open access to test cases as well as step-by-step user guides. While the current report is limited to the two most widely commercially available MBDCAs and only for Ir-192-based afterloading brachytherapy at this time, this report establishes a general framework that can easily be extended to other brachytherapy MBDCAs and brachytherapy sources. The AAPM, ESTRO, ABG, and ABS recommend that clinical medical physicists implement the workflow presented in this report to validate both the basic and the advanced dose calculation features of their commercial MBDCAs. Recommendations are also given to vendors to integrate advanced analysis tools into their brachytherapy treatment planning system to facilitate extensive dose comparisons. The use of the test cases for research and educational purposes is further encouraged.
Address [Beaulieu, Luc; Ma, Yunzhi] CHU Quebec Univ Laval, Serv Phys Med & Radioprotect, Quebec City, PQ, Canada, Email: beaulieu@phy.ulaval.ca
Corporate Author Thesis
Publisher Wiley Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0094-2405 ISBN Medium
Area Expedition Conference
Notes WOS:001026540300001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5579
Permanent link to this record
 
 
Author Candela-Juan, C.; Ballester, F.; Perez-Calatayud, J.; Vijande, J.
Title Assaying multiple I-125 seeds with the well-ionization chamber SourceCheck(4 Pi) 33005 and a new insert Type Journal Article
Year 2015 Publication Journal of Contemporary Brachytherapy Abbreviated Journal J. Contemp. Brachytherapy
Volume 7 Issue 6 Pages 492-496
Keywords (up) brachytherapy; insert; quality assurance; prostate; seeds; well chamber
Abstract Purpose: To provide a practical solution that can be adopted in clinical routine to fulfill the AAPM-ESTRO recommendations regarding quality assurance of seeds used in prostate permanent brachytherapy. The aim is to design a new insert for the well-ionization chamber SourceCheck(4 Pi) 33005 (PTW, Germany) that allows evaluating the mean air-kerma strength of up to ten I-125 seeds with one single measurement instead of measuring each seed individually. Material and methods: The material required is: a) the SourceCheck(4 Pi) 33005 well-ionization chamber provided with a PTW insert to measure the air-kerma strength S-K of one single seed at a time; b) a newly designed insert that accommodates ten seeds in one column, which allows measuring the mean S-K of the ten seeds in one single measurement; and c) a container with ten seeds from the same batch and class of the seeds used for the patient implant, and a set of nine non-radioactive seeds.The new insert is characterized by determining its calibration coefficient, used to convert the reading of the well-chamber when ten seeds are measured to their mean S-K. The proposed method is validated by comparing the mean S-K of the ten seeds obtained from the new insert with the individual measurement of S-K of each seed, evaluated with the PTW insert. Results: The ratio between the calibration coefficient of the new insert and the calibration coefficient of the PTW insert for the SourceCheck(4 Pi) 33005 is 1.135 +/- 0.007 (k = 1). The mean S-K of a set of ten seeds evaluated with this new system is in agreement with the mean value obtained from measuring independently the S-K of each seed. Conclusions: The new insert and procedure allow evaluating the mean S-K of ten seeds prior to the implant in a single measurement. The method is faster and more efficient from radiation protection point of view than measuring the individual S-K of each seed.
Address [Candela-Juan, Cristian; Perez-Calatayud, Jose] La Fe Univ, Dept Radiat Oncol, Phys Sect, E-46026 Valencia, Spain, Email: ccanjuan@gmail.com
Corporate Author Thesis
Publisher Termedia Publishing House Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1689-832x ISBN Medium
Area Expedition Conference
Notes WOS:000368381300010 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 2533
Permanent link to this record
 
 
Author Bazeia, D.; Losano, L.; Menezes, R.; Olmo, G.J.; Rubiera-Garcia, D.
Title Robustness of braneworld scenarios against tensorial perturbations Type Journal Article
Year 2015 Publication Classical and Quantum Gravity Abbreviated Journal Class. Quantum Gravity
Volume 32 Issue 21 Pages 215011 - 10pp
Keywords (up) brane-worlds; tensorial perturbations; metric-affine geometry
Abstract Inspired by the peculiarities of the effective geometry of crystalline structures, we reconsider thick brane scenarios from a metric-affine perspective. We show that for a rather general family of theories of gravity, whose Lagrangian is an arbitrary function of the metric and the Ricci tensor, the background and scalar field equations can be written in first-order form, and tensorial perturbations have a non negative definite spectrum, which makes them stable under linear perturbations regardless of the form of the gravity Lagrangian. We find, in particular, that the tensorial zero modes are exactly the same as predicted by Einstein's theory regardless of the scalar field and gravitational Lagrangians.
Address [Bazeia, D.; Losano, L.; Olmo, Gonzalo J.] Univ Fed Paraiba, Dept Fis, BR-58051900 Joao Pessoa, Paraiba, Brazil, Email: bazeia@fisica.ufpb.br;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0264-9381 ISBN Medium
Area Expedition Conference
Notes WOS:000364921200014 Approved no
Is ISI no International Collaboration yes
Call Number IFIC @ pastor @ Serial 2459
Permanent link to this record
 
 
Author Soriano, A.; Gonzalez, A.; Orero, A.; Moliner, L.; Carles, M.; Sanchez, F.; Benlloch, J.M.; Correcher, C.; Carrilero, V.; Seimetz, M.
Title Attenuation correction without transmission scan for the MAMMI breast PET Type Journal Article
Year 2011 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 648 Issue Pages S75-S78
Keywords (up) Breast PET; Attenuation correction
Abstract Whole-body Positron Emission Tomography (PET) scanners are required in order to span large Fields of View (FOV). Therefore, reaching the sensitivity and spatial resolution required for early stage breast tumor detection is not straightforward. MAMMI is a dedicated breast PET scanner with a ring geometry designed to provide PET images with a spatial resolution as high as 1.5 mm, being able to detect small breast tumors ( < 1 cm). The patient lays down in prone position during the scan, thus making possible to image the whole breast, up to regions close to the base of the pectoral without the requirement of breast compression. Attenuation correction (AC) for PET data improves the image quality and the quantitative accuracy of radioactivity distribution determination. In dedicated, high resolution breast cancer scanners, this correction would enhance the proper diagnosis in early disease stages. In whole-body PET scanners, AC is usually taken into account with the use of transmission scans, either by external radioactive rod sources or by Computed Tomography (CT). This considerably increases the radiation dose administered to the patient and time needed for the exploration. In this work we propose a method for breast shape identification by means of PET image segmentation. The breast shape identification will be used for the determination of the AC. For the case of a specific breast PET scanner the procedure we propose should provide AC similar to that obtained by transmission scans as we take advantage of the breast anatomical simplicity. Experimental validation of the proposed approach with a dedicated breast PET prototype is also presented. The main advantage of this method is an important dose reduction since the transmission scan is not required.
Address [Soriano, A.; Orero, A.; Moliner, L.; Carles, M.; Sanchez, F.; Benlloch, J. M.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46980 Paterna, Spain, Email: soriano@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:000305376900021 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 1069
Permanent link to this record