Cesium atomic beam clocks have been the workhorse for many demanding applications in science and technology for the past four decades. Tests of the fundamental laws of physics and the search for minute changes in fundamental constants, the synchronization of telecommunication networks, and realization of the satellite-based global positioning system would not be possible without atomic clocks. ...

Multicast is an efficient way to support emerging multimedia services over wireless network. Fountain codes are used in multicast systems to enable a robust transmission without CSI feedback and ARQ. We propose a cooperative multicast scheme based on fountain code to improve the performance of multicast. The users are coordinated with each other to decode the message at different time slots wit...

We describe an unusual case of delayed retropneumoperitoneum caused by a deep vaginal laceration as a result trauma from a water jet in a fountain. A 7-year-old premenarcheal girl presented to the emergency department after experiencing an injury from a water jet at a fountain park. Initially, the patient's vital sign and perineum were within normal range. Because the patient's vital signs beca...

We present evidence for cosmological gas accretion onto spiral galaxies in the local universe. The accretion is seen through its effects on the dynamics of the extra-planar neutral gas. The accretion rates that we estimate for two nearby spiral galaxies are of the order of their star formation rates. Our model shows that most of the extra-planar gas is produced by supernova feedback (galactic f...

The use of fountain codes in wireless cooperative relay networks can improve the system performance in aspects such as transmission time, energy consumption, transmission efficiency and outage probability etc. This has been proved when the number of the relay nodes and their relaying capabilities are stationary. But in practical networks the relay nodes are variable and dynamic. This paper prop...

Recently, data of taken with the OSSE experiment have been combined with scanning observations by TGRS and SMM to produce maps of the narrow Galactic 511 keV line emission (Purcell et al. 1997). A modelling of the combined data give evidence for three distinct features: the Galactic plane, a central bulge, and an extended emission region at positive latitudes above the Galactic center. It has b...

BACKGROUND A gastroenteritis outbreak was associated with playing in a norovirus-contaminated recreational fountain. OBJECTIVE AND STUDY DESIGN A retrospective cohort study was performed to estimate the magnitude of the outbreak and identify its source. Epidemiological investigation included standardized questionnaires about sex, age, school, class, risk exposures, and illness characteristics...

The inefficient usage of limited radio spectrum resources with its increased demand has opened the doors for an innovative communication technology. The recently proposed concept of cognitive radio network can use the licensed bands of primary users for its data transmission without causing interference to them. The LT (Luby Transform) code and Raptor code, types of Fountain codes (class of era...