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.
High oil prices also can reduce demand for other goods because they reduce wealth, as well as induce uncertainty about the future (Sill 2007). One way to analyze the effects of higher oil prices is to think about the higher prices as a tax on consumers (Fernald and Trehan 2005).