 Discipline, an academic discipline or academic field is a branch of knowledge. It incorporates expertise, people, projects, communities, challenges, studies, inquiry, and research areas that are strongly associated with a given scholastic subject area or college department. For example, the branches of science are commonly referred to as the scientific disciplines, e.g. physics, mathematics, and biology. Individuals associated with academic disciplines are commonly referred to as experts or specialists. Others who may have studied liberal arts or systems theory rather than concentrating in a specific academic discipline are classified as generalists. While academic disciplines in and of themselves are more or less focused practices, scholarly approaches such as multidisciplinarity, interdisciplinarity, transdisciplinarity, and cross-disciplinarity integrate aspects from multiple academic disciplines, therefore addressing any problems that may arise from narrow concentration within specialized fields of study. For example, professionals may encounter trouble communicating across academic disciplines because of differences in language or specified concepts. Some researchers believe that academic disciplines may be replaced by what is known as modu or post-academic science which involves the acquisition of cross-disciplinary knowledge through collaboration of specialists from various academic disciplines.