We demonstrate that black holes and stars in general relativity can be destabilized by perturbations of non-minimally coupled vector fields. Focusing on static spherically symmetric backgrounds, our analysis shows with sufficiently small mass high densities are subject to ghost or gradient-type instabilities. This holds for a large class vector-tensor theories whenever non-minimal couplings con...

This work deals with the convergence analysis of parabolic perturbations to quasilinear wave equations on smooth bounded domains. In particular, we consider nonlinearities quadratic type, which cover two classical models nonlinear acoustics, Westervelt and Kuznetsov equations. By employing a high-order energy analysis, obtain their solutions corresponding inviscid equations' in standard norm li...

One of primary reasons for the establishment of the ARM Southern Great Plains research site was to obtain long-term records of surface radiation data and the impact of clouds on these data (Stokes and Schwartz 1994). This research project focuses on the creation of a two-year climatology of the surface radiation budget and the impact of clouds on that budget. The period of analysis extends from...

background: congenital adrenal hyperplasia (cah) and vanishing testes are uncommon diseases that can result from hormonal and mechanical factors. classic cah is determined by ambiguous genitalia and increase in amount of 17-hydroxyprogesterone. simultaneous occurrence of cah and vanishing testes is a rare condition. case: a 22-year-old boy, known case of cah who was diagnosed as female pseudohe...

Family businesses are an important factor for technological progress and high economic efficiency, determining a significant part of economic strength. At present, inside the European Monetary Union (EMU), there are efforts to reduce public debt to fulfill the criteria imposed by the Stability and Growth Pact (SGP), which are mandatory for members of the Euro zone. Due to these constraints, pub...

This paper present a study of the relationship between subglottal pressure (SGP) and intensity of the speech signal in the case of sustained French oral vowels with controlled pitch. The corpus is based on a male and a female subjects, the SGP is measured directly by tracheal puncture. The results show that the relationship between intensity and subglottal pressure varies when one considers the...

This paper introduces a new algorithm to detect aerosols and clouds based on micropulse lidar measurements. A semidiscretization processing technique is first used to inhibit the impact of increasing noise with distance. The value distribution equalization method which reduces the magnitude of signal variations with distance is then introduced. Combined with empirical threshold values, we deter...

We show that for any spacetime dimension greater than or equal to four, the Einstein equations for gravitational perturbations of maximally symmetric vacuum black holes can be reduced to a single 2nd-order wave equation in a two-dimensional static spacetime, irrespective of the mode of perturbations. Our starting point is the gauge-invariant formalism for perturbations in an arbitrary dimension...

We consider the problem of matching perspective views of coplanar structures composed of line segments. Both model-to-image and image-to-image correspondence matching are given a consistent treatment. These matching scenarios generally require discovery of an eight parameter projective mapping. However, when the horizon line of the object plane can be found in the image, done here using vanishi...