The amplitude and frequency of such tides is affected by the moon's location as it revolves around the Earth. The gravitational pull of the moon creates a tidal bulge at the location directly beneath its location. Every two weeks or so, the moon aligns with the Earth and sun in a straight line -- the new and full moon phases -- resulting in the maximum gravitational force on our planet's oceans. These periods are referred to as spring tides..
http://d3fzrw9hngh8qa.cloudfront.net/glossary/CORECountries.mp4. According to a way of thinking about economies known as World Systems Theory, CORE countries are strong and wealthy countries that generate lots of wealth, and on which other countries depend. In the 14th century, Mongolia was a CORE country, and Italy was a peripheral country.
2. a. the central, innermost, or most essential part of something: the core of the argument. b. (as modifier): the core meaning. 3. (General Physics) a piece of magnetic material, such as soft iron, placed inside the windings of an electromagnet or transformer to intensify and direct the magnetic field. number of people or objects that form the centre or main part of a group, organization, or society; players in a curling match; miners in one shift, hence, core of people, 1622.