Short-lived greenhouse gases that also contribute to air pollution are playing a major role in global warming. Black carbon alone is likely the second or third most important climate forcing agent. The short atmospheric lifetime of these pollutants means that, unlike CO2, reducing emissions produces a decrease in atmospheric concentration and a reduction of the radiative forcing that drives cli...

OBJECTIVE To evaluate the influence of meteorological factors on the onset of aneurysmal subarachnoid haemorrhage in Hong Kong. DESIGN Retrospective review of prospectively collected data. SETTING University teaching hospital, Hong Kong. PATIENTS A total of 135 consecutive patients with acute aneurysmal subarachnoid haemorrhage presenting to the hospital within 48 hours after ictus from O...

heavy precipitation plays a significant role in arid and semi-arid regions of iran. in order to understand the effect of blocking high system on rainfalls in northwest iran during 25 - 28 october 2008, meteorological conditions including pressure, wind fields and temperature at multiple levels of the atmosphere were analyzed. sea level pressure, the 1000-500 hpa thickness, perceptible water, re...

Laser action at 530 nm using H3 centers in diamond was observed with an efficiency of 13.5% at room temperature. Optical double-resonance experiments on N3 centers provided direct evidence for a (2)A metastable level. Its presence results in rapid decay of the excited (2)E state and low quantum efficiency as well as significant excited-state absorption in the N3 luminescence region.

Observational studies have revealed a rich low-frequency structure in the atmosphere. A review of the theories, observations, and model studies of this low-frequency atmospheric variability is presented. On time scales of weeks or longer the atmosphere appears to possess distinct oscillatory behavior in welldefined and persistent "centers of action." This behavior is also an endemic feature of ...

The influence of atmospheric environment is fundamental for Free-Space Optical link (FSO). The atmosphere can significantly degrade the communication quality of FSO up to so low received power/RSSI level that it can lead to the loss of communication. For this reason, authors used a professional weather station built on site of FSO link for measurement of real atmospheric conditions such as wind...

The experimental studies of thermoacoustic cooler consisting of acoustic loop-tube were carried out. The loop-tube was filled with the mixture of air and helium gas or air at atmospheric pressure. The dimensions of the loop-tube were 3.3 m of length, 44 mm of inner diameter and 4 mm of thickness. A pair of stacks (stack 1 and stack 2) which were sandwiched between two heat exchangers was placed...