Satellite tracking involves sending electromagnetic signals to Earth. Both the orbit of the spacecraft and the electromagnetic signals themselves are affected by the curvature of spacetime. The arrival time of the pulses is compared to the ticks of local clocks to reconstruct the orbital path of the satellite to high accuracy, and implicitly measure general relativistic effects. In particular, ...

Line emission from an accretion disk and a corotating hotspot about a rotating black hole are considered for possible signatures of the frame dragging eeect. We explicitly compare integrated line prooles from a geometrically thin disk about a Schwarzschild and an extreme Kerr black hole and show that the line proole diierences are small if the inner radius of the disk is near or above the Schwa...

background: orbital mucormycosis caused by zygomycetes is a rare and fatal infection that generally affects the patients who  are  immunocompromised.  despite  antifungal  therapy  and  aggressive  surgical  intervention,  mucormycosis  can cause serious and rapidly fatal infections if delayed diagnosis or therapeutic management occurs. here, we report orbital mucormycosis in a healthy boy, wit...

Line emission from an accretion disk and a corotating hotspot about a rotating black hole are considered for possible signatures of the frame dragging effect. We explicitly compare integrated line profiles from a geometrically thin disk about a Schwarzschild and an extreme Kerr black hole and show that the line profile differences are small if the inner radius of the disk is near or above the S...

submitted to WPGM, 2006 The IGS precise orbits of GPS have been widely used in the world ever since the beginning of their broadcast in 1994. Major changes have taken place both in the data processing softwares and the reference frame over the years, but the orbits have not been updated. In this study we reanalyzed the GPS data from the IGS global tracking station since 1994 and compared our re...

A tree code method that incorporates a local shearing disc model and fourth-order integration algorithm is applied to the problem of planetary rings, with particular emphasis on the dynamics of Saturn's B ring. The new code, described in detail elsewhere, allows for particle self-gravity, a distribution of particle sizes, and surface friction (particle spin). Important changes made to the origi...

We construct a set of reference frames for description of the orbital and rotational motion of the Moon. We use a scalar-tensor theory of gravity depending on two parameters of the parametrized post-Newtonian (PPN) formalism and utilize the concepts of the relativistic resolutions on reference frames adopted by the International Astronomical Union in 2000. We assume that the solar system is iso...

The focus of this work is the current distribution asteroids in co-orbital motion with Venus, Earth and Jupiter, under a quasi-coplanar configuration for medium-term timescale order 900 years. A trajectory heliocentric orbit trapped 1:1 mean-motion resonance given planet. As such, to model it considers Restricted Three-Body Problem circular-planar case help averaging techniques. domain each reg...

This paper deals with continuous frames and continuous Riesz bases. We introduce continuous Riesz bases and give some equivalent conditions for a continuous frame to be a continuous Riesz basis. It is certainly possible for a continuous frame to have only one dual. Such a continuous frame is called a Riesz-type frame [13]. We show that a continuous frame is Riesz-type if and only if it is a con...

purpose : to report a rare case of isolated orbital mucocele after trauma case report : a 45-year-old man presented with swelling in the left orbital region. the only significant event in his medical history was trauma which occurred 25 years previously during the iran-iraq war. computed tomography revealed a left medial intraorbital cystic mass lesion. the cystic mass was completely removed th...