We the compare the number of phrases created by Ziv/Lempel '78 parsing of a binary sequence and of its reversal. We show that the two parsings can vary by a factor that grows at least as fast as the logarithm of the sequence length. We then show that under a suitable condition, the factor can even become polynomial, and argue that the condition may not be necessary.

Al Madinah Al Munawarah, Kingdom of Saudi Arabia (KSA) has one of the largest number of expatriate workers. Most of them are from Sri-Lanka, Indonesia, Philippines, India and Bangladesh. These countries are considered as endemic areas for intestinal parasites. A total of 2732 stool samples were screened for intestinal parasites. Positive cases were recorded among 407 stool samples (14.9%). The ...