Results 51 to 60 of about 408,529 (289)

Locally-homogeneous Riemann-Cartan geometries with the largest symmetry group [PDF]

J. Math. Phys. 65, 072502 (2024)
The symmetry frame formalism is an effective tool for computing the symmetries of a Riemann-Cartan geometry and, in particular, in metric teleparallel geometries. In the case of non-vanishing torsion in a four dimensional Riemann-Cartan geometry, the Minkowski geometry is the only geometry admitting ten affine frame symmetries. Excluding this geometry,
arxiv   +1 more source

T-Symmetry in String Geometry Theory

Advances in High Energy Physics
String geometry theory is one of the candidates of nonperturbative formulation of string theory. In this paper, we have shown that dimensionally reduced string geometry theories have what we call T-symmetry.
Matsuo Sato, Taiki Tohshima
doaj   +1 more source

Routine machine quality assurance tests for a self‐shielded gyroscopic radiosurgery system

Journal of Applied Clinical Medical Physics, EarlyView.
Abstract Purpose This report describes routine machine quality assurance (QA) (daily, monthly, and annual QA) tests for the Zap‐X® Gyroscopic Radiosurgery® platform. Methods Following the recommendations of the American Association of Physicists in Medicine Task Group (AAPM TG)‐142 and Medical Physics Practice guideline (MPPG) 8.b, routine machine QA ...
Yongsook C. Lee, Ranjini Tolakanahalli, D Jay Wieczorek, Minesh P. Mehta, Michael W. McDermott, Rupesh Kotecha, Alonso N. Gutierrez   +6 more
wiley   +1 more source

Use of geometry and featural cues in landmark configurations to reorient DCD children to the VR space: A route-learning study

Revista de Investigación e Innovación en Ciencias de la Salud, 2023
Background. Working memory-based spatial cognition has attracted the attention of the scientific community in navigation and reorientation projects.
Chrysanthi Basdekidou, Athanasios Styliadis, Alexandros Argyriadis, Levente Dimen   +3 more
doaj   +1 more source

AAPM‐RSS Medical Physics Practice Guideline 9.b: SRS‐SBRT

Journal of Applied Clinical Medical Physics, EarlyView.
Abstract The purpose of this Medical Physics Practice Guideline (MPPG) is to describe the minimum level of medical physics support deemed prudent for the practice of linear‐accelerator, photon‐based (linac) stereotactic radiosurgery (SRS), and stereotactic body radiation therapy (SBRT) services.
Eileen Cirino, Stanley H. Benedict, Pamela J. Dupre, Per H. Halvorsen, Grace Gwe‐Ya Kim, Meral L. Reyhan, Christopher W. Schneider, Lei Wang, Carl P. Weaver, Sua Yoo   +9 more
wiley   +1 more source

Novel Symmetries in Christ-Lee Model [PDF]

Europhys. Lett. 115 (2016) 21003, 2015
We demonstrate that the gauge-fixed Lagrangian of the Christ-Lee model respects four fermionic symmetries, namely; (anti-)BRST symmetries, (anti-)co-BRST symmetries within the framework of BRST formalism. The appropriate anticommutators amongst the fermionic symmetries lead to a unique bosonic symmetry.
arxiv   +1 more source

Evaluation of OPTOS wide‐field fundus image projections for radiotherapy planning of uveal melanoma

Journal of Applied Clinical Medical Physics, EarlyView.
Abstract Purpose To investigate the relationship between the stereographic and azimuthal equidistant projection (AEP) of the human retina for radiotherapy planning with OPTOS optomap wide‐field fundus images (Optos, UK). Further, the geometric accuracy of an OPTOS fundus image is quantified.
Jörg Wulff, Benjamin Koska, Michael Giese, Christian Bäumer, Ronald Richter, Andreas Foerster, Nikolaos E. Bechrakis, Beate Timmermann   +7 more
wiley   +1 more source

Modelling of a double‐scattering proton therapy nozzle using the FLUKA Monte Carlo code and analysis of linear energy transfer in patients treated for prostate cancer

Journal of Applied Clinical Medical Physics, EarlyView.
Abstract Background The dose‐averaged linear energy transfer (LETD) in proton therapy (PT) has in pre‐clinical studies been linked to the relative biological effectiveness (RBE) of protons. Until recently, the most common PT delivery method in prostate cancer has been double‐scattered PT, with LETD only available through dedicated Monte Carlo (MC ...
Rasmus Klitgaard, Lars Fredrik Fjæra, Camilla Hanquist Stokkevåg, Perry Johnson, Mark Artz, Nancy Price Mendenhall, Curtis Bryant, Ludvig Paul Muren   +7 more
wiley   +1 more source

Automatic skin flash optimization in breast and chestwall VMAT with static angle modulated ports: Effect of HU and flash margin size on plan quality and robustness

Journal of Applied Clinical Medical Physics, EarlyView.
Abstract Skin flash is typically added to breast and chestwall plans to ensure robust target coverage in the presence of respiratory motion, anatomic changes, and small setup uncertainties. Adding skin flash in volumetric modulated arc therapy (VMAT) plans is an iterative and manual process.
Emily Hubley, Brandon Koger, Taoran Li, Michael Salerno, Ryan M. Scheuermann, Lei Dong, Boon‐Keng Kevin Teo   +6 more
wiley   +1 more source

Symmetries and conformal bridge in Schwarschild-(A)dS black hole mechanics

Journal of High Energy Physics, 2021
We show that the Schwarzschild-(A)dS black hole mechanics possesses a hidden symmetry under the three-dimensional Poincaré group. This symmetry shows up after having gauge-fixed the diffeomorphism invariance in the symmetry-reduced homogeneous Einstein-Λ
Jibril Ben Achour, Etera R. Livine
doaj   +1 more source