We estimate the possible variations of the gravitational constant G in the framework of a generalized (BergmannWagoner-Nordtvedt) scalar-tensor theory of gravity on the basis of the field equations, without using their special solutions. Specific estimates are essentially related to the values of other cosmological parameters (the Hubble and acceleration parameters, the dark matter density etc....

The Machian cosmological solution satisfying φ = O(ρ/ω) for the perfect-fluid with negative pressure is discussed. When the coefficient of the equation of state γ → −1/3, the gravitational constant approaches to constant. If we assume the present mass density ρ0 ∼ ρc (critical density), the parameter ǫ (γ = (ǫ− 1)/3) has a value of order 10−3 to support the present gravitational constant. The c...

Our main objective was to test whether chronic orthostatic body position induces network changes in the saphenous vein superficial tributary system of the rat. Fourteen male Sprague-Dawley rats were kept in tilted tube cages (45-degree head-up position) for two weeks to induce chronic gravitational load to their leg veins. Ten animals housed in normal cages and four animals kept in horizontally...

Conventional non-Abelian SO(4) gauge theory is able to describe gravity provided the gauge field possesses a specific polarized vacuum state. In this vacuum the instantons and antiinstantons have a preferred direction of orientation. Their orientation plays the role of the order parameter for the polarized phase of the gauge field. The interaction of a weak and smooth gauge field with the polar...

g – standard gravitational acceleration, m/s μ gravitational constant, km/s mdry – spacecraft mass without fuel, kg mwet – spacecraft mass with total fuel, kg mhighF – high-thrust system fuel mass, kg mHSTF – hybrid system fuel mass, kg m02 – spacecraft mass after phase 1 of the transfer, kg ∆Vhigh – high-thrust only system ∆V, m/s ∆VH – high-thrust portion of hybrid system ∆V, m/s ∆VL – low-th...

A discussion is given of the uncertainty principle in view of the introduction of a Gravitational Planck Constant. The need for such a gravitational constant is shown first. A reduced electromagnetic Planck constant and the analogous reduced gravitational Planck constant are defined as h/e and H/m respectively. An attempt is made to reconcile the quantum uncertainty concepts with a deterministi...

The effect of introducing a fifth large-scale space-time dimension to the equations of orbital dynamics was analysed in an earlier paper by the authors. The results showed good agreement with the observed flat rotation curves of galaxies. This analysis did not require the modification of Newtonian dynamics, but rather only their restatement in a five dimensional framework. The same analysis der...