Current, accumulating evidence for (mildly) relativistic blueand red-shifted absorption lines in AGNs is reviewed. XMM-Newton and Chandra sensitive X-ray observations are starting to probe not only the kinematics (velocity) but also the dynamics (accelerations) of highly ionized gas flowing in-and-out from, likely, a few gravitational radii from the black hole. It is thus emphasized that X-ray ...

According to experimental studies, low-amplitude high-frequency vibration is anabolic to bone tissue, whereas in clinical trials, the bone effects have varied. Given the potential of whole body vibration in bone training, this study aimed at exploring the transmission of vertical sinusoidal vibration to the human body over a wide range of applicable amplitudes (from 0.05 to 3 mm) and frequencie...

The center of mass (COM) of a flying animal accelerates through space because of aerodynamic and gravitational forces. For vertebrates, changes in the position of a landmark on the body have been widely used to estimate net aerodynamic forces. The flapping of relatively massive wings, however, might induce inertial forces that cause markers on the body to move independently of the COM, thus mak...

We analyze the development of a gas-solid flow in an axisymmetric shear cell without gravitational accelerations. A gas pressure gradient imposed on the cell induces a relative motion between the two phases, while the differential rotation of the cell boundaries allows the independent control of the solids agitation. We model variations of the cross-sectional averaged solid volume fraction, mea...

Physical mechanisms that can influence rotation curves of spiral galaxies are discussed. For dark matter studies, possible contributions due to magnetic fields and non-Newtonian gravitational accelerations should be carefully acconted for. We point out that magnetic fields are particularly important in outermost parts of the disk. In the framework of general relativity the physical reason of an...

New measurements of the velocity dispersion of the globular cluster ω Centauri allow to trace its gravitational potential down to an acceleration of 8 × 10 cm s. It is found that the dispersion profile remains flat well inside the tidal radius as soon as the acceleration of gravity approaches a0, a result that finds its simplest explanation within the contest of MOND. A similar behavior is obse...

The Bonnor–Swaminarayan solutions are boost-rotation symmetric space-times which describe the motion of pairs of accelerating particles which are possibly connected to strings (struts). In an explicit and unified form we present a generalised class of such solutions with a few new observations. We then investigate the possible limits in which the accelerations become unbounded. The resulting sp...

It has been recently claimed that there is no correlation between the distribution of galaxies and their peculiar velocities within the Local Volume (LV), namely a sphere of R = 7hMpc around the Local Group (LG). It has been then stated that this implies that either locally dark matter is not distributed in the same way as luminous matter, or peculiar velocities are not due to fluctuations in m...

The objective of GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) is the determination of the Earth’s gravity field with high spatial resolution. The main science sensor (the gradiometer) measures differential accelerations, from which the gravitational gradients, i.e. the matrix of the second derivatives of the gravitational potential, are derived. Some of them (the diagonal co...