Results 51 to 60 of about 197,944 (293)

Bounce Conditions in f(R) Cosmologies

, 2005
We investigate the conditions for a bounce to occur in Friedmann-Robertson-Walker cosmologies for the class of fourth order gravity theories. The general bounce criterion is determined and constraints on the parameters of three specific models are given ...
Capozziello S, Capozziello S, Carloni S, Deon Solomons, Dicke R, Ellis G F R, Ellis G F R Sachs R K, Gibbons G, Peter K S Dunsby, Sante Carloni, Schmidt H J, Schwarz J H, Singh P Toporensky A, Smolin L, Smolin L, Solomons D, Starobinskii A A, Tolman R C, Townsend P K   +18 more
core   +1 more source

de Sitter bounces [PDF]

Classical and Quantum Gravity, 2004
By analytically continuing recently-found instantons, we construct time-dependent solutions of Einstein-Maxwell de Sitter gravity which smoothly bounce between two de Sitter phases. These deformations of de Sitter space undergo several stages in their time evolution.
Lü, H., Vázquez-Poritz, Justin F., Wang, John E.   +2 more
openaire   +3 more sources

An intracellular transporter mitigates the CO2‐induced decline in iron content in Arabidopsis shoots

FEBS Letters, EarlyView.
This study identifies a gene encoding a transmembrane protein, MIC, which contributes to the reduction of shoot Fe content observed in plants under elevated CO2. MIC is a putative Fe transporter localized to the Golgi and endosomal compartments. Its post‐translational regulation in roots may represent a potential target for improving plant nutrition ...
Timothy Mozzanino, Meijie Li, Cécile Fizames, Mattia Adamo, Laurence Lejay, Christian Dubos, Matthieu Platre, Antoine Martin   +7 more
wiley   +1 more source

Different Aspects of Entropic Cosmology

Universe
We provide a short review of the recent developments in entropic cosmology based on two thermodynamic laws of the apparent horizon, namely the first and the second laws of thermodynamics.
Shin’ichi Nojiri, Sergei D. Odintsov, Tanmoy Paul   +2 more
doaj   +1 more source

Probing a black-bounce-Reissner–Nordström spacetime with precessing and periodic motion

European Physical Journal C: Particles and Fields, 2022
We investigate the precessing and periodic orbits of a test timelike particle around the black-bounce-Reissner–Nordström spacetime which is characterized by its charge and bounce parameter.
Jing Zhang, Yi Xie
doaj   +1 more source

Big bounce from spin and torsion

, 2012
The Einstein-Cartan-Sciama-Kibble theory of gravity naturally extends general relativity to account for the intrinsic spin of matter. Spacetime torsion, generated by spin of Dirac fields, induces gravitational repulsion in fermionic matter at extremely ...
A. Ashtekar, A. Kashlinsky, A. Trautman, A. Trautman, B. Kuchowicz, D.A. Easson, D.W. Sciama, D.W. Sciama, E.A. Lord, E.W. Kolb, F.W. Hehl, F.W. Hehl, F.W. Hehl, F.W. Hehl, F.W. Hehl, F.W. Stecker, H. Fritzsch, H. Harari, H. Terazawa, I.S. Nurgaliev, J. Rich, J. Smoller, J. Tafel, J. Weyssenhoff, J.A. Barros de, J.C. Pati, K. Nomura, L. Parker, L. Smolin, L.D. Landau, M. Bañados, M. Bojowald, M. Bojowald, M. Gasperini, M. Novello, M.A. Shupe, N.J. Popławski, N.J. Popławski, N.J. Popławski, Nikodem J. Popławski, P. Laurent, P. Peter, P. Peter, R.K. Pathria, S.D. Brechet, T.W.B. Kibble, V. Sabbata de, V.N. Melnikov, V.P. Frolov, V.P. Frolov, W. Kopczyński, W. Kopczyński, W.M. Stuckey, Y. Ne’eman, Y.N. Obukhov   +54 more
core   +1 more source

Time after time – circadian clocks through the lens of oscillator theory

FEBS Letters, EarlyView.
Oscillator theory bridges physics and circadian biology. Damped oscillators require external drivers, while limit cycles emerge from delayed feedback and nonlinearities. Coupling enables tissue‐level coherence, and entrainment aligns internal clocks with environmental cues.
Marta del Olmo, Carolin Ector, Hanspeter Herzel   +2 more
wiley   +1 more source

Following the primordial perturbations through a bounce with AdS/CFT correspondence

European Physical Journal C: Particles and Fields, 2018
A bounce universe model, known as the coupled-scalar-tachyon bounce (CSTB) universe, has been shown to solve the Horizon, Flatness and Homogeneity problems as well as the Big Bang singularity problem.
Lei Ming, Taifan Zheng, Yeuk-Kwan E. Cheung   +2 more
doaj   +1 more source

Numerical study on influences of parallel sonic wave damping, precession, and bounce resonances on resistive wall modes in CFETR

AIP Advances, 2022
Adopting an 11 MA steady-state reversed magnetic shear equilibrium of the China Fusion Engineering Test Reactor, the influence of parallel sonic wave damping, precession, and bounce resonances on the resistive wall mode (RWM) at different plasma ...
Shilong Li, Yue Liu
doaj   +1 more source

Observational signatures of a non-singular bouncing cosmology

, 2011
We study a cosmological scenario in which inflation is preceded by a bounce. In this scenario, the primordial singularity, one of the major shortcomings of inflation, is replaced by a non-singular bounce, prior to which the universe undergoes a phase of ...
A. Lewis, C. Cartier, D. Wands, D.A. Easson, D.M. Solomons, J. Martin, J. Martin, J.D. Barrow, L.R. Abramo, Larissa Lorenz, M. Lilley, Marc Lilley, P. Peter, P. Peter, R. Brandenberger, R. Brandenberger, R. Durrer, R. Lehoucq, S. Alexander, S. Carloni, S. Clesse, S. Kachru, S. Tsujikawa, Sébastien Clesse, V.F. Mukhanov, WMAP collaboration, WMAP collaboration, Y.-F. Cai, Y.-F. Cai   +28 more
core   +3 more sources