51.   Brehmer had subjects attempt to estimate the number of road accidents occurring at various junctions and compared these estimates with the actual figures.

52.   These situations may be characterised not by the actual risk felt in the situation but by the potential for risky situations to occur at the junction.

53.   These occurred at different times down the whole length of the front, from Haj Omran in the mountains of the north to the marshes in the south.

54.   The point at which this occurs is known as the FLORY or THETA point and is in some ways analogous to the Boyle point for a non-ideal gas.

55.   Thus significant fractionation of O isotopes occurs only at the surface of the Earth.

56.   Halving of the chromosome number occurs at gametogenesis by meiosis.

57.   An operant is a piece of behaviour which has a spontaneous nature which occurs at a predetermined frequency.

58.   If anything unusual occurs at one of these phases a fixation at the relevant phase occurs.

59.   This occurs at high pressure.

60.   The temperature at which this occurs is called the boiling point of the liquid.