A hiatal hernia does not cause many symptoms by itself, but when a sliding hernia occurs, the abnormal location of the gastroesophageal (GE) junction above the diaphragm affects its function and stomach contents can reflux into the esophagus.
-You need to work on sentence structuring. For example, when you wrote, The immigration, as a decision maked by a person is an act that occurs, because of some factors especially in the under developed countries and the most importants causes or reasons are mainly social reasons, politic reasons and economic reasons..
Immigration Laws: 1) Quota Act of 1921 limited immigration from each country to 3 % of total number who had immigrated in 1910 and set a yearly limit of 350,000. 2) The 1924 quota reduced the quota to 2%, the base year changed from 1910 to 1890.