In general it is known that due to the complex nature of the gene expression data sets themselves and the experimental errors in detecting the gene expression data, it is difficult to discover an acknowledged best clustering approach.
When a sequence contains more than one motif, it is difficult to discover all the motifs.
It is difficult to discover any point in calling talk "rabbit and pork".
The evolutionary reasons for reproductive success are difficult to discover in a society that uses modern birth control methods.
In real estate, residences with a sordid past are referred to as "stigmatized properties" and it can be difficult to discover if a house falls into this category, since neither the seller, nor the seller's real estate agent, may be under any obligation to disclose that information.
Education of both patients and primary physicians is also important, as the alarm symptoms develop slowly and may be clinically difficult to discover for a long period of time.
The large number of NRs (48 in humans) makes it time-consuming and difficult to discover such a network using conventional molecular techniques alone (Bookout et al, 2006; Yang et al, 2006).
These men are called 'germinal mosaics', and it is difficult to discover them without a testicular biopsy.
But the inherent nature of cryptocurrencies — which are typically traded anonymously on a decentralized network without the need for a bank account — makes it difficult to discover the nature of a partner's investment or holding.
He found it difficult to discover anyone who had a bad word to say about him, either during his life or since.
