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..
The Immigration Act of 1924 created a permanent quota system (that of 1921 was only temporary), reducing the 1921 annual quota from 358,000 to 164,000. In addition, the Act reduced the immigration limit from 3 percent to 2 percent of each foreign-born group living in the United States in 1890.