Growing degree-day. Growing degree days (GDD), also called growing degree units (GDUs), are a heuristic tool in phenology. GDD are a measure of heat accumulation used by horticulturists, gardeners, and farmers to predict plant and animal development rates such as the date that a flower will bloom, an insect will emerge from dormancy, or a crop will reach maturity.
Cystic fibrosis is a genetic condition caused by a faulty gene (known as the CFTR gene). The CFTR gene normally creates a protein that moves salt and water out of a cell.If the CFTR gene is defective, it results in a build-up of thick, sticky mucus in the body's tubes and passageways.ystic fibrosis is a genetic condition caused by a faulty gene (known as the CFTR gene). The CFTR gene normally creates a protein that moves salt and water out of a cell.
1 Cystic fibrosis primarily affects the lungs and digestive system. 2  It leads to the production of mucus that is much thicker and more sticky than usual. 3  Cystic fibrosis is a hereditary condition, caused by a defective gene. 4  The cystic fibrosis gene must be present in both parents for a child to have the condition. It leads to the production of mucus that is much thicker and more sticky than usual. 2  Cystic fibrosis is a hereditary condition, caused by a defective gene. 3  The cystic fibrosis gene must be present in both parents for a child to have the condition.