Речь идет о статистическом показателе размера газеты. Имеется такой отрывок:
We are interested in obtaining a good proxy for newspaper size and we use the word "and" because it appears in almost all articles. On the Newslibrary. com archive it is in fact possible to search for the blank ("") string and get all available articles in a given newspaper during a given time interval. However, some other archives like LexisNexis and Factiva do not allow a search for the blank string; for the purposes of replicability on other news archives, we have decided to use "and" as our proxy. Using a blank string instead of "and" produces essentially identical results.
Про союз "и" более менее понятно, а вот что такое blank string -- неясно совершенно. Пробел? Пустая строка?
Уважаемые сообщники, поделитесь своими соображениями, плиз.