We consider the evolution in full general relativity of a family of linearly unstable isolated spherical neutron stars under the effects of very small perturbations as induced by the truncation error. Using a simple idealfluid equation of state, we find that this system exhibits a type I critical behaviour, thus confirming the conclusions reached by Liebling et al (2010 arXiv:1001.0575v1) for r...

Flux-limited Keller-Segel (FLKS) model has been recently derived from kinetic transport models for bacterial chemotaxis and shown to represent better the collective movement observed experimentally. Recently, associated to the kinetic model, a new instability formalism has been discovered related to stiff chemotactic response. This motivates our study of traveling wave and aggregation in popula...

In a recent paper [M. Leo, R. A. Leo, and P. Tempesta, J. Stat. Mech. (2011) P03003], it has been shown that the π/2-mode exact nonlinear solution of the Fermi-Pasta-Ulam β system, with periodic boundary conditions, admits two energy density thresholds. For values of the energy density ε below or above these thresholds, the solution is stable. Between them, the behavior of the solution is unsta...

We study the existence and instability properties of saddleshaped solutions of the semilinear elliptic equation −∆u = f(u) in the whole R, where f is of bistable type. It is known that in dimension 2m = 2 there exists a saddle-shaped solution. This is a solution which changes sign in R and vanishes only on {|x1| = |x2|}. It is also known that this solution is unstable. In this article we prove ...

Background: Unstable angina and myocardial infarction are developed due to atherosclerosis of coronary arteries. At present, cholestrol, triglyceride, and lipoproteins are the most common risk factors of death. The purpose of this study was to assess the serum levels of LP (a), LDL-C, VLDL-C, HDL-C in cases of unstable angina and myocardial infarction.Methods: This study was conducted to compar...

Drying of a sessile drop of a complex liquid can lead to intriguing complex shapes. We report here a study dealing with a model system, made of a hydrosoluble polymer that is glassy when pure. Under solvent evaporation, polymers accumulate near the vapor/drop interface and may form a glassy skin, which bends as the volume of liquid it encloses decreases. The conditions for the occurrence of thi...

Nifedipine (NIF) a 1, 4-dihydropyridine calcium channel antagonist, undergoes photodegradation to nitroso analogues of dehydronifedipine (NDNIF) when exposed to sunlight. Photodegradation products of NIF have no clinical activity, so different formulations of NIF must remain unchanged. If NIF preparations become unstable in exposure to light, they could cause therapeutic failure. The present st...