Neutrophils are the most common type of white blood cell, comprising about 50-70% of all white blood cells. They are phagocytic, meaning that they can ingest other cells, though they do not survive the act. Neutrophils are the first immune cells to arrive at a site of infection, through a process known as chemotaxis.
One of the basic theories stipulates that increasing interest rates raise consumers' and manufacturers' costs, which, in turn, reduces the amount of time and money people spend driving. Less people on the road translates to less demand for oil, which can cause oil prices to drop.
When interest rates are low, companies are induced, by the low borrowing costs, to issue bonds. As more companies borrow in the bond market, the supply of bonds increases. This raises competition in the markets for investor dollars, which means that interest rates tend to rise to attract investors.