By VOAWelcome back to As It Is.Today we will be talking about people who move to the United States from other countries.Some are immigrants who bring their traditions with them. On our show, we look at families from Latin American nations. Many of them celebrate a young woman's quincea?era—that is, her 15th birthday.But first, we talk about foreign students in the United States. A new report says the government should make it easier for foreigners working toward high-level degrees to stay in the country.Mario Ritter has this report from VOA's Joe DeCapua.The United States educates many foreign students, especially in areas like science and engineering. But what do international students add to the country after they finish their study programs?Three economists decided to investigate. The head of the team was Keith Maskus, a professor at the University of Colorado in Boulder. He says after the terrorist attacks of September 11, 2001, the U.S. made it much harder for students from some parts of the world to enter graduate programs.At the time, many American officials and educators warned that limiting foreign students would harm scientific development and innovation."And I thought, well, that's very interesting, but do we really know if that's true?"Professor Maskus worked on the study with Ahmed Mushfiq Mobarak of Yale and Eric Stuen of the University of Idaho. The three men gathered data—a lot of data.They studied over 75,000 Ph.D students in the top U.S. science and engineering universities from the late 1970s to the late 1990s.They found that diversity improved productivity and efficiency. In other words, a mix of American and foreign students made schools and workplaces better and faster."It seems to have something to do with the fact that networks and laboratory sciences [are] really a function of how the graduate students and the post- doctoral students and everyone else can specialize in some element of science - and also the fact that their undergraduate training and possibly some graduate training in whatever it is - mathematics or bench science or laboratory science - gives them different approaches to thinking about problems."And when these people can get together and bounce ideas off each other the sort of outcome of that is more dynamic intellectual process. And you get more ideas with having some diversity like that."Professor Maskus says his group's findings suggest that the U.S. should change its policies toward foreign students. Right now, students have to demonstrate that they or their family has enough money to pay for their education, even if schools offer aid.He also says the government should make it easier for foreign students to get green cards so they can live permanently in the United States.He notes that countries like Canada and Australia let international students with Ph.Ds in science, technology or engineering become permanent residents. But the United States requires students who want to remain in the country to find a local employer who will give them a temporary visa."That does have the effect, we're convinced, of pushing too many of these innovative people back outside the borders of the United States."Professor Maskus and his team want the U.S. to offer more temporary visas, or even just a quick and easy process for permanent residence.Of course, others might argue that permitting foreign students to stay in the U.S. will take jobs away from American workers.But the researchers say the economic and creative gains of diversity outweigh any harmful effects for native-born Americans.Their report appeared in the journal Science.I'm Kelly Jean Kelly. Many cultures celebrate the passage from childhood to adulthood. In some Latin American countries, young women mark this passage at age 15. Many Latin American families in the United States not only continue the tradition, but go to great lengths to celebrate quincea?era.Recently, party planners organized a show all about quincea?era in Los Angeles, California. Thirteen-year-old Adilen Torres and her mother attended the exhibit to research prices and gather ideas. Adilen Torres says the celebration will be a time to express her identity."I want people to know that what they see on the outside isn't everything that I am. So I want my quincea?era to represent everything I am."Her mother, Nellie Viveros, says the celebration is an important part of Latino culture."Kids nowadays, our kids, are very Americanized and this is a part of their culture that we want them to follow tradition with. This is my only daughter and it's once in a lifetime thing. I'm willing to sacrifice and work overtime to do the quincea?era for her." Experts say that over the past 10 years quincea?era have grown in size. Norma Capitanachi works for Quinceanera Magazine. She says the celebrations have also become more costly. The average family spends about $10,000, she says. But some families pay $50,000 or up to $80,000.Celia Barrios is a professional quincea?era planner. She has organized about 300 of the parties in Los Angeles, California. Ms. Barrios says people often want to celebrate in a fancy, pricey place. And, they want others to make and serve the food, choreographers to organize the event, and designers to create specially-made dresses."Latino Americans that are born and raised here or have spent at least 10 to 15 years here, they're wanting more. They kind of want to blend the tradition with something contemporary. And you know that's where I come in."Some people criticize quincea?eras as a waste of money. They say the money could be used instead to pay for education or other things. But for many parents it is a special event that helps keep traditions alive.It may also be a way for a family to celebrate their own success in their new country. Helen Hernandez says her family struggled in the United States at first. But by the time their daughter Tatyana turned 15, they were able to throw her the kind of party she wanted."We're so blessed and thankful that we were able to move it around and do this."Tatyana says she really appreciated the sacrifices her parents made for her.And her parents say seeing her happy made all their efforts worth it.And that's As It Is. I'm Kelly Jean Kelly.Thanks for listening.