Results 11 to 20 of about 1,179 (183)

Muscle Imaging in Inclusion Body Myositis: Refinement of MRI Criteria and Insights Into Upper Body Involvement. [PDF]

J Cachexia Sarcopenia Muscle
ABSTRACT Background The diagnosis of inclusion body myositis (IBM) can be delayed because of its heterogeneous clinical presentation and the lack of specific biomarkers. Muscle imaging has gained increasing relevance over the past decade and is now included among the supportive criteria in the international diagnostic guidelines.
Torchia E, Lucchini M, Verdu-Diaz J, Bortolani S, Ravera B, Carlomagno V, Cicia A, Bernardo D, Monforte M, Rehmann R, Kley RA, Sabatelli M, Díaz-Manera J, Ricci E, Mirabella M, Tasca G.   +15 more
europepmc   +2 more sources

The Cotton Tensor and the Ricci Flow [PDF]

Geometric Flows, 2017
AbstractWe compute the evolution equation of the Cotton and the Bach tensor under the Ricci flow of a Riemannian manifold, with particular attention to the three dimensional case, and we discuss some applications.
Carlo Mantegazza, Samuele Mongodi, Michele Rimoldi   +2 more
openaire   +4 more sources

Ricci Collineations for Non-degenerate, Diagonal and Spherically Symmetric Ricci Tensors [PDF]

General Relativity and Gravitation, 2000
The expression of the vector field generator of a Ricci Collineation for diagonal, spherically symmetric and non-degenerate Ricci tensors is obtained. The resulting expressions show that the time and radial first derivatives of the components of the Ricci tensor can be used to classify the collineation, leading to 64 families.
Contreras, G., Núñez, L. A., Percoco, U.   +2 more
openaire   +2 more sources

A Note on the Geometry of RW Space-Times

Mathematics, 2023
A conformally flat GRW space-time is a perfect fluid RW space-time. In this note, we investigated the influence of many differential curvature conditions, such as the existence of recurrent and semi-symmetric curvature tensors.
Sameh Shenawy, Uday Chand De, Nasser Bin Turki   +2 more
doaj   +1 more source

On the Geometry of the Riemannian Curvature Tensor of Nearly Trans-Sasakian Manifolds

Axioms, 2023
This paper presents the results of fundamental research into the geometry of the Riemannian curvature tensor of nearly trans-Sasakian manifolds. The components of the Riemannian curvature tensor on the space of the associated G-structure are counted, and
Aligadzhi R. Rustanov
doaj   +1 more source

An axially symmetric spacetime with causality violation in Ricci-inverse gravity

European Physical Journal C: Particles and Fields, 2023
In this paper, Ricci-inverse gravity is investigated. It is an alternative theory of gravity that introduces into the Einstein–Hilbert action an anti-curvature scalar that is obtained from the anti-curvature tensor which is the inverse of the Ricci ...
J. C. R. de Souza, A. F. Santos
doaj   +1 more source

Scalar–tensor gravitation and the Bakry–Émery–Ricci tensor [PDF]

Classical and Quantum Gravity, 2013
The Bakry-Emery generalized Ricci tensor arises in scalar-tensor gravitation theories in the conformal gauge known as the Jordan frame. Recent results from the mathematics literature show that standard singularity and splitting theorems that hold when an energy condition is applied in general relativity also hold when that energy condition is applied ...
openaire   +5 more sources

On the Almost $\eta-$Ricci Solitons on Pseudosymmetric Lorentz Generalized Sasakian Space Forms

Universal Journal of Mathematics and Applications, 2023
In this paper, we consider Lorentz generalized Sasakian space forms admitting almost $\eta-$Ricci solitons in some curvature tensors. Ricci pseudosymmetry concepts of \ Lorentz generalized Sasakian space forms admitting $\eta-$Ricci soliton have ...
Mehmet Atçeken, Tuğba Mert
doaj   +1 more source

Classification of the Ricci tensor [PDF]

Communications in Mathematical Physics, 1971
This paper contains a classification of the Ricci tensorRαβ. The method of derivation is analogous to the spinor version of the Petrov classification of the Weyl tensor. It is shown how the various classes are related to the number and type of eigenvectors and eigenvalues ofRαβ. The classification is useful in the geometrization of various fields.
Ludwig, Garry, Scanlan, Gerry
openaire   +2 more sources

Multidimensional gravity with higher derivatives and inflation

Physics Letters B, 2020
We elaborate on the inflationary model starting from multidimensional Lagrangian and gravity with second-order curvature terms. The effective scalar field is related to the Ricci scalar of extra dimensions.
Júlio C. Fabris, Arkady A. Popov, Sergey G. Rubin   +2 more
doaj   +1 more source