The actin cytoskeleton helps maintain structural organization within living cells. In large X. laevis oocytes, gravity becomes a dominant force and is countered by a nuclear actin network that prevents liquid-like nuclear bodies from immediate sedimentation and coalescence. However, nuclear actin's mechanical properties, and how they facilitate the stabilization of nuclear bodies, remain unknow...

The quantum field theory of gravitation is constructed in terms of Lagrangian density of Dirac fields which couple to the electromagnetic field Aμ as well as the gravitational field G. The gravity appears in the mass term as m(1+gG)ψ̄ψ with the coupling constant of g. In addition to the gravitational force between fermions, the electromagnetic field Aμ interacts with the gravity as the fourth or...

The choice of the best optimization algorithm is a hard issue, and it sometime depends on specific problem. The Gravitational Search Algorithm (GSA) is a search algorithm based on the law of gravity, which states that each particle attracts every other particle with a force called gravitational force. Some revised versions of GSA have been proposed by using intelligent techniques. This work pro...

Virial theorem is important for understanding stellar structures. It produces an interesting connection between magnetic and gravitational energies. Using the general form of the virial theorem including the magnetic field (toroidal magnetic field), we may explain the solar dynamo model in relation to variations of the magnetic and gravitational energies. We emphasize the role of the gravitatio...

The modified Newtonian dynamics (MOND) has been proposed as an alternative to the dark matter paradigm; the philosophy behind is that there is no dark matter and we witness a violation of the Newtonian law of dynamics. In this article, we interpret differently the phenomenology sustaining MOND, as resulting from an effect of “gravitational polarization”, of some cosmic fluid made of dipole mome...

The modified Newtonian dynamics (MOND) has been proposed as an alternative to the dark matter paradigm; the philosophy behind is that there is no dark matter and we witness a violation of the Newtonian law of dynamics. In this Letter, we interpret differently the phenomenology sustaining MOND, as resulting from an effect of “gravitational polarization”, of some cosmic fluid made of dipole momen...

We investigate a calculation method for the gravitational evolution of an extreme mass ratio binary, i.e. a binary constituting of a galactic black hole and a stellar mass compact object. The inspiralling stage of this system is considered to be a possible source of detectable gravitational waves. Because of the extreme mass ratio, one may approximate such a system by a black hole geometry (a K...

We study the effect of cosmological expansion on orbits–galactic, planetary, or atomic–subject to an inverse-square force law. We obtain the laws of motion for gravitational or electrical interactions from general relativity–in particular, we find the gravitational field of a mass distribution in an expanding universe by applying perturbation theory to the Robertson-Walker metric. Cosmological ...

We present an approximation scheme for gravitational force near arbitrarily shaped small bodies. The approximation uses polynomial interpolation with an adaptive spatial data structure. This data structure allows us to drive errors in the model to within user defined thresholds. The result is a method that is expected to reduce the run time of trajectory integrations around small bodies without...