Investigating the momentum balance of a plasma pinch: an air-side stereoscopic imaging system for locating probes.

The momentum balance of a plasma pinch in the Reconnection Scaling Experiment (RSX) is examined in three dimensions using several repositionable, insertable probes. A new camera-based system described here triangulates the locations of the probe tips so that their measurements are spatially registered. The optical system locates probes to within ±1.5 mm of their absolute 3D position in the vessel and to within ±0.7 mm relative to other probes, on the order of the electron inertial length (1-2 mm).

Detecting cAMP with an EPAC-based FRET sensor in single living cells.

Cyclic nucleotides such as cGMP and cAMP play pivotal roles as second messengers in many biological processes. Upon stimulation of appropriate signal transduction pathways, the levels of these messengers change rapidly. Such variations in second messenger level may also be spatially restricted within the cell. To detect dynamic and local changes in second messengers, we need to study them in living cells with high spatial and temporal resolution. Focusing on cAMP, here we describe how imaging of an EPAC-based FRET sensor in single cells provides that spatiotemporal resolution.

Ammonia emissions from cattle, pig and poultry wastes applied to pasture.

In four field experiments, carried out in The Netherlands, small wind-tunnels were used to make direct measurements of ammonia (NH(3)) volatilization from different types of slurry and manure applied to the surface of grassland. During periods of up to six days following application, losses of NH(3)-N often amounted to more than 40% of the NH(4)-N applied. Percentage loss was highest (83%) from a poultry slurry and least (21%) from an air-dried poultry manure. Losses of NH(3)-N were generally greater from pig slurry (36-78%) than from cattle slurry (41%). In most cases 80% or more of the total NH(3)-N loss occurred within 48 h of application. Estimates were made of total annual NH(3) emissions from four systems of poultry housing. The highest total loss (50% of the N voided in droppings) occurred with a battery house producing a slurry with a low content of dry-matter; most of the loss took place after spreading. With a second battery house, in which the droppings were air-dried, the total loss was only 12%, with much lower emissions from the housing and during spreading.