1.   A biopsy of brain tissue detected the presence of toxoplasmosis, which is relatively harmless in people with normally functioning immune systems.

2.   All fish can detect the presence of objects near them even if they can not see them.

3.   Nevertheless, there are various ways by which scientists can detect their presence.

4.   Products of the chain reaction were fractionated by size in agarose gels to detect the presence of insertions or deletions.

5.   The new system can detect the presence of dangerous but invisible microorganisms like salmonella and e. coil bacteria.

6.   They detect the presence of carrion by sight.

7.   They invented a device for detecting the presence of submarines.

8.   The test is used to detect the presence of alcohol in the blood.

9.   New methods of detecting the presence of organic compounds in fish suggest that pollutants may be killing them and other marine species in smaller concentrations than previously thought.