The Tipping Point

When a liquid-liquid interface is to be investigated using an electrode in the more dense phase, or for studies at the water-air interface, a submarine electrode can be deployed [18,19,34], depicted schematically in Fig. 3(b). In this case, the electrode is inverted in the cell, such that the tip points upwards, and an insulated connection is made through the solution. Metal electrodes down to the nanometer scale can also be fabricated by sealing an etched Pt or Pt-Ir wire in a suitable insulating material, leaving just the etched end exposed [35-37]. 

The decision of which quantum mechanical model to use boils down to what size molecule you want to calculate, how reliable an answer you want, and how much time are you willing to wait for the results. Fortunately, as software and hardware improve, the tipping point of the balance weighing the pros and cons of semiempirical vs. DFT vs. ab initio is shifting such that larger molecules can be handled by the better methods. In special situations, a molecule with a couple of hundred atoms can be treated by an ab initio method (46,47), but the typical molecule of interest to theorists, spectrosco-pists, and physicists is smaller than what a pharmaceutical chemist usually wants to treat. Large molecular systems are often best left to one of the FF approaches (see next section). 

Terrestrial runoff is a major concern for areas with coral reefs. Nutrient enrichment, sedimentation, and turbidity can all degrade reefs at local scales (Fabricius, 2005). While there are some coastal coral reefs that can flourish in relatively high nutrient and high levels of particulate matter, they tend to be restricted in depth to 10 m whereas in clearer offshore reefal systems they may extend to >40 m (Fabricius, 2005). Some corals can use the particulate matter for nutrition. However, there is a fine line, between increased nutrient availabdity for the coral for ingestion and the tipping point at which the corals are unable to cope with sedimentation and silting affects. (Anthony, 2000 Anthony and Fabricius, 2000 Fabricius and Wolanski, 2000 Mills and Sebens, 2004 Mills et ah, 2004). 

With tertiary or more stable carbocations, we would have one extreme, with the carbocation comer low enough in energy to be the two-step intermediate. Secondary carbocations seem to be the tipping point. The following arrows are for the corresponding two-step processes via an intermediate carbocation. 

While the tipping points for Supply Chain 2020 seem far off on the horizon, now is the tune to prepare. The supply chain of the future cannot be built overnight and there is substantial momentum in today s organization that must be overcome. To drive success, build momentum by following this nine-step process ... 

GladweU, Malcolm. The Tipping Point How Little Things Can Make a Big Difference. Back Bay Books, Boston, 2002. 

There are two types of stability checks that should be performed on each load. The first has to do with the tipping point of the load relative to the roadway as the load shifts due to the camber of the road. The second has to do with the turning radius of bolstered loads. As the load goes around curves, the C.G. shifts from being in line with the dollies, to an eccentric condition. In tight curves the... 

Bixby, R., Rothberg, E., 2007. Progress in computational mixed integer programmiiig— A look back from the other side of the tipping point. Anru Open Res. 49(1), 37-41. 

These uncertainties raise a number of questions about how regulators should respond. Is it acceptable to say we do not know enough so we should wait until more evidence emerges Where is the tipping point, the imperative to act, when weighing up the evidence If history has taught us anything, it is that we can ill afford to be complacent. 

Gladwell, M. (2000), The Tipping Point, Boston Little, Brown and Company. 

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