The General Assembly has expressed the following views :

i.- There is to be no refereeing system - any paper submitted is to be accepted.

ii.- A maximum of two parallel sessions is acceptable. Of course the two subject areas should be as remote from one another as possible. Moreover, the popularity of poster sessions seems to have virtually eliminated the need for parallel sessions.

Many people prefer to give their papers as posters, and it is normal to ask in the second circular for a preference as between oral and poster presentation. Official acceptance of contributed papers, and the handbook itself, should not distinguish between oral and poster presentation in case this should affect claims for expenses. However, since different preparation is required it is, of course, essential to inform contributors in good time which option they are getting.


In principle only one poster or oral contribution should be accepted per participant. Collaborating authors can have more contributions between them, but for each contribution a different participant shall count. In case that even in this way the number of contributions tends to become too large, the organisers could contact some of the larger laboratories to ask them to lower the number of contributions, but they shall not require them to do so.

1. Poster sessions

i.- Contributors must be notified well in advance of the area (normally about 2m2) and facilities available. The organisers should also give some prescriptions for the posters : they should be legible from a distance of about two meters, so the letters should have a minimum size of 8mm for lower case and 12mm for upper case. The figures should equally comply with these rules. Further information can be made available for those really interested in details in another way, e.g. as photocopies distributed at the posters. If there are any special instructions for mounting posters, then these must be made known to participants well in advance.

ii.- A plan of "who is where" must be available to conference participants.

iii.- The length of time a Poster Session should last depends on the number of contributors, but should be a minimum of two hours. This may well include a coffee break if poster and coffee areas are reasonably close. The Poster area should be as central as possible. Poster and oral sessions should not run in parallel.

iv.- Time for mounting and dismantling posters outside other scheduled activities must be allowed. If there is more than one poster session, the first presenters must be given a deadline for clearing the area for their successors. Subject to this limitation, posters should be left up as long possible - preferably at least 24 hours.

v.- The problem of both standing by one's own poster and looking at others in the same session is probably best solved by affixing a time-table to each poster showing when the author will actually be available for discussion.

2.- Oral sessions

The General Assembly has expressed the following views :

i.- Insofar as is possible the author's preference for oral or poster presentation will be followed, but the local committee should be free to transfer a few papers to poster sessions rather than run an additional parallel session.

ii.- All papers delivered orally shall be allotted a minimum of 15 minutes (12 minutes for presentation, 3 for discussion).

iii.- The organisers may wish to advise institutes to require their younger speakers (and some of the older ones as well, if necessary) to hold some trial talks to ensure a proper presentation.

iv.- It is desirable to have some contributed papers given in plenary sessions; these may be allotted a longer time, say 20 or 25 minutes. The selection is made by the local Committee, and the presenters must be informed well before the Conference.



3. Parallel sessions

A maximum of two parallel sessions is acceptable. It is as well for a Conference Organiser to be aware of the problems associated with parallel sessions, even though there may be little he can do about them. They all arise from the fact that some people will want to listen to papers in both sessions. The most serious drawback of parallel sessions is thus that participants may be forced to miss papers which they would have found interesting. The golden rule is therefore to make the two subject areas as orthogonal as possible when planning the program. This has the added advantage of reducing the flow of participants backwards and forwards between the lecture rooms. Such movement causes more or less inconveniences depending on the type of seating, the positions of doors, the acoustics, and when people choose to move.

Practically, the only factor for the Conference organiser has under his control is the amount of information people have in deciding when to move. There is a good case for keeping each session informed about the progress of the other. The papers are numbered in the handbook; the numbers of the papers being presented at any instant in both sessions could be displayed at all times in both lecture theatres. This information should also be available in the coffee area. Closed circuit television, or a computer link, could easily be used.

The advantages of such a system are that unnecessary journeys would be avoided (and hence the inconvenience to others), and that people would not miss the paper they wished to hear (or arrive half an hour too early for them), so reducing frustration. The disadvantage is the danger of a mass stampede from one lecture theatre to another when a popular paper is about to begin, so that some unfortunate speaker loses most of his audience in a noisy exodus. This does not happen if people are unaware of the progress of the other session since they generally leave at the end of a contribution. However, in this case the discussion of a paper, which can bring up important points, tends to be disrupted.

A major factor in the success of parallel sessions is the choice of chairman. Much more than in plenary sessions, it is important that they should be capable of exercising some control over the speakers and audience, prompting discussions, and coping with unforeseen problems. However, one cannot expect most chairmen to try to prevent people from going in and out during talks or discussion; in any case, such appeals (though usually greeted with noisy approval) have only a limited and short-term effect. Finally, it is quite unrealistic to rely on being able to keep two parallel sessions "in phase". However strongly they are urged, some contributors will not keep to their allotted time and most chairmen will not force them to do so.