Precise Doppler searches for extrasolar planets find a surfeit of planets with orbital periods of 3–4 days, and no planets with orbital periods less than 3 days. The circumstellar distance, R0, where small grains in a protoplanetary disk reach sublimation temperature (∼ 1500 K) corresponds to a period of∼ 6 days. Interior to R0, turbulent accretion due to magneto-rotational instability may evac...

We show, by means of a perturbative weakly nonlinear analysis, that the axisymmetric magneto-rotational instability (MRI) in a magnetic Taylor-Couette (mTC) flow in a thin-gap gives rise, for very small magnetic Prandtl numbers (Pm), to a real Ginzburg-Landau equation for the disturbance amplitude. The saturation amplitude As is found to scale in this regime as P m, with 1/2 < δ < 2/3 (dependin...

The method of generating a family of new solutions starting from any wave function satisfying the nonlinear Schrödinger equation in a harmonic potential proposed recently @J. J. Garcı́a-Ripoll, V. M. Pérez-Garcı́a, and V. Vekslerchik, Phys. Rev. E 64, 056602 ~2001!# is extended to the many-body theory of mutually interacting particles. Our method is based on a generalization of the displacement o...

BACKGROUND AND PURPOSE High pressures around implants can cause bone lysis and loosening. We investigated how pressures are generated around cemented femoral stems. METHOD We compared the pressures generated by rough and polished tapered stems at their cement interfaces, in an in vitro model, before and after 1 million load cycles. RESULTS At the start of the study, the loading of both poli...

We analyze the energy extraction by the Penrose process in higher dimensions. Our result shows the efficiency of the process from higher dimensional black holes and black rings can be rather high compared with than that in four dimensional Kerr black hole. In particular, if one rotation parameter vanishes, the maximum efficiency becomes infinitely large because the angular momentum is not bound...

We study the density instabilities of a two-dimensional gas of dipolar fermions with aligned dipole moments. The random phase approximation (RPA) for the density-density response function is never accurate for the dipolar gas, and so we incorporate correlations beyond RPA via an improved version of the Singwi-Tosi-Land-Sjölander scheme. In addition to density-wave instabilities, our formalism c...

A general theory of heteroepitaxial lateral growth of nanocrystallites via successive nucleation at the concave corner of the nanocrystallite and the substrate was developed. The theory treats the existence of a rotational instability of crystallographic orientation induced by the imbalance of surface/interface energy. From the theory it can be concluded that the crystallographic orientation ma...

We study the vacuum, plane-wave Bianchi V IIh spacetimes described by the Lukash metric. By combining covariant with orthonormal frame techniques, we describe these models in terms of their irreducible kinematical and geometrical quantities. This covariant description is used to study analytically the response of the Lukash spacetime to linear perturbations. We find that the stability of the va...

We study the longitudinal spin susceptibility inside a magnetically ordered phase, which exhibits superconducting instability leading to coexistence of two phases. Inside magnetic gap acquires linear term in field applied along direction moment. find that such generates jump when occurs via continuous phase transition. This anomaly at is thermodynamic signature microscopic superconductivity and...

The magnetorotational instability (MRI) of a weakly ionized, differentially rotating, magnetized plasma disc is investigated in the multi-fluid framework. The disc is threaded by a uniform vertical magnetic field and charge is carried by electrons and ions only. The inclusion of ion inertia causes significant modification to the conductivity tensor in a weakly ionized disc. The parallel, Peders...