Nervous system would not exist without the human brain. Most neurons send signals via their axons, although some types are capable of dendrite-to-dendrite communication. (In fact, the types of neurons called amacrine cells have no axons, and communicate only via their dendrites.) Neural signals propagate along an axon in the form of electrochemical waves called action potentials, which produce cell-to-cell signals at points where axon terminals make synaptic contact with other cells. Synapses may be electrical or chemical. Electrical synapses make direct electrical connections between neurons, but chemical synapses are much more common, and much more diverse in function. At a chemical
Journal of Physical and Chemical Reference Data Journal of Physical and Chemical Reference Data The Journal of Physical and Chemical Reference Data is a quarterly peer-reviewed scientific journal published by AIP Publishing on behalf of the National Institute of Standards and Technology. The objective of the journal is to provide critically evaluated physical and chemical property data, fully documented as to the original sources and the criteria used for evaluation, preferably with uncertainty analysis. The editors-in-chief are Donald R. Burgess, Jr, and Allan H. Harvey. The journal is abstracted and indexed in the Science Citation Index Expanded and Current Contents/Physical Chemical and Earth Sciences. According to the