List<Concept> r = getNeighbors(doc);
List<Annotation> annotations = new ArrayList<Annotation>();
// check for negation
NegEx negex = new NegEx();
negex.process(concept.getSearchString(),Collections.singletonList(concept));
if(negex.getNegatedConcepts().contains(concept)){
setAbsent(true);
// add negation annotation
for(Concept c: negex.getNegations())
Collections.addAll(annotations,c.getAnnotations());