Barometer Simultaneous barometric readings from across a network of weather stations allow maps of air pressure to be produced, which were the first form of the modern weather map when created in the 19th century. Isobars, lines of equal pressure, when drawn on such a map, give a contour map showing areas of high and low pressure. Localized high atmospheric pressure acts as a barrier to approaching weather systems, diverting their course. Atmospheric lift caused by low-level wind convergence into the surface brings clouds and sometimes precipitation. The larger the change in pressure, especially if more than 3.5 hPa (0.1 inHg),
Desorption atmospheric pressure photoionization separation technique that can be coupled with DAPPI-MS to identify lipids. Some of the lipids that were seen to be separated and ionized include: cholesterol, triacylglycerols, 1,2-diol diesters, wax esters, hydrocarbons, and cholesterol esters. TLC is normally coupled with instruments in vacuum or atmospheric pressure, but vacuum pressure gives poor sensitivity for more volatile compounds and has minimal area in the vacuum chambers. DAPPI was used for its ability to ionize neutral and non-polar compounds, and was seen to be a fast and efficient method for lipid detection as it was coupled with both NP-TLC and HPTLC plates. Laser desorption