What is investment spending and what are the factors that impact investment demand?
Investment spending is a component of Aggregate Demand. The components of AD are: consumption, investment, government spending, and (imports - exports). The two main factors that drive investment are the interest rate (i) and future levels of expected income (Ye). If the interest rate goes down, money is 'cheaper' to borrow, and you will see an increase in firms' investment. If they think they'll make tons of money in the future (an increase in their future income expectations), they'll be more willing to borrow money to invest. In short, the two main factors driving investment are the interest rate (i) and future income expectations (Ye). Edit: To add--the above post is spot on.
How impact factor of some journal is calculated?
Impact factors are attributes of journals in the sciences and social sciences. They measure the number of times articles in that journal are subsequently cited in relation to the number of articles in that jounal. The higher the impact factor, the more often people tend to quote from articles in that journal. One catalogue of impact factors is at the website below (or you could always put "impact factor" into Google and find these things out for yourself).