The dynamical shear instability is an important mixing process in the advanced stages of the evolution of massive stars. We calculated different models of 15 M⊙ with an initial rotational velocity, υini = 300 km/s to investigate its efficiency. We found that the dynamical shear instability has a timescale shorter than Oxygen burning timescale and that it slightly enlarges the convective zones a...

An analysis is presented of parametric instability in a finite-length rotating cylinder subject to periodic axial compression by small sinusoidal oscillations of one of its ends (the ‘piston’). The instability is due to resonant interactions between inertialwave (Kelvin) modes of the cylinder and the oscillatory compression and is resisted by viscosity, acting both through thin boundary layers ...

Vortices and black holes set the scene for many interesting dynamical processes in physics. Here, we study instability of quantized vortices rotational superradiance around rotating holes, illustrating process that same physics is at play these two seemingly disparate phenomena. We also compare vortex to hole bomb instability, which occurs massive scalar fields Kerr spacetime. Taking inspiratio...

Magnetically mediated disk outflows are a leading paradigm to explain winds and jets in a variety of astrophysical sources, but where do the fields come from? Since accretion of mean magnetic flux may be disfavored in a thin turbulent disk, and only fields generated with sufficiently large scale can escape before being shredded by turbulence, in situ field production is desirable. Nonlinear hel...

Recurrent shoulder instability and resultant glenoid and humeral head bone loss are not infrequently encountered in the population today, specifically in young, athletic patients. This review on the management of bone loss in recurrent glenohumeral instability discusses the relevant shoulder anatomy that provides stability to the shoulder joint, relevant history and physical examination finding...

Scapholunate joint takes approximately 80% of axial and rotational wrist load. Lesion of scaphoid ligaments leads to its instability especially in dorsal flexion and ulnar deviation mechanism. Increase of scapholunate gap can be found in 19% of patient with wrist injury, 2 of them needs surgical intervention because of severe instability. In 2002 to 2005 in Traumatology, Orthopedics and Hand Su...

Electronic-nematic phases are broadly characterized by spontaneously broken rotational symmetry. Although they have been widely recognized in the context of high temperature cuprates, bilayer ruthenates, and iron-based superconductors, the focus so far has been exclusively on the uniform nematic phase. Recently, however, it was proposed that on a square lattice a nematic instability in the d-wa...

Recently Andersson et. al., and Bildsten have independently suggested that an r-mode instability might be responsible for stalling the neutron-star spin-up in strongly accreting, Low Mass X-ray Binaries (LMXBs). We show that if this does occur, then there are two possibilities for the resulting neutron-star evolution: If the r-mode damping is a decreasing function of temperature, then the star ...