What was going on when I was born?

''It's increasingly a battle between artists and technology. We have to band together to insure that New York never becomes another Pittsburgh or Seattle or Houston.''

The basic fare rate for medallion taxis - 90 cents a mile, not including the $1 ''drop charge'' imposed at the start of each trip - barely covers expenses for many cabs, according to a city-commissioned report released yesterday. These costs, the study found, range from 83.5 cents a mile for certain mini-fleet taxis to 90.5 cents a mile for driver-owned vehicles. A companion survey based on a reading of ''trip tickets'' for two days in 1981 also disclosed that the typical driver of medallion taxis collects about $4 on each metered fare and altogether records gross income ranging from $90 to $110 per shift before tips. The figures were made public by the Mayor's Committee on Taxi Regulatory Issues, which was formed a year ago. The committee is expected to put forth its recommendations next week on possible changes in the industry that could affect the cost, safety and availability of taxis.

THE growing popularity of a nonsurgical treatment for periodontal disease has touched off a national debate among periodontists, many of whom say that the therapy, which has never been scientifically tested, may be inadequate to control the major cause of tooth loss in adult Americans. The new treatment, aimed at suppressing the infection that is thought to be the underlying cause of periodontal disease, involves thorough professional cleanings and assiduous daily home care using such antibacterial agents as salt, baking soda and hydrogen peroxide. At the heart of the controversy is an issue that has often arisen in medical care in recent years: the pitting of new, simpler, less expensive methods of care against established remedies that are supported by decades of experience, clinical studies and a widely accepted scientific rationale. In the treatment of breast cancer, for example, the once-routine radical mastectomy has recently yielded to more modified surgery or radiation therapy, which are now widely believed to be as effective as the more disfiguring operation. The nonsurgical approach to treating periodontal disease is achieving popularity at a time when surgery of all sorts is being challenged as often unnecessary or unnecessarily extreme, and when health care economists are searching for less expensive ways of delivering effective care.

CAPE CANAVERAL, Fla. WITHIN 40 minutes after the Columbia's launching yesterday, the first data from the scientific instruments on board began flowing back to the earth, signals from the most elaborate payload yet to fly in the space shuttle's cargo bay. Several teams of scientists, from universities and Government agencies, began poring over the data, in part to learn something more about solar radiations and flares and the orbital environment, but also to evaluate the shuttle's performance as a vehicle for scientific observations. The Columbia's cargo of scientific and technological experiments weighs more than 21,000 pounds, four times the load of freight carried on the second flight last November. Of particular interest to scientists is the set of nine instruments known as the O.S.S.-1 payload, for the National Aeronautics and Space Administration's Office of Space Science.

The Money Market Mutual Funds table in Business Day last Friday misstated the assets of the Alex Brown Cash Reserve and the Value Line Cash Fund. Alex Brown has $559.5 million in assets and Value Line $533.4 million.

A picture caption accompanying the Going Out Guide yesterday was incorrect. The picture showed Thad Jones.

An article in Business Day last Tuesday understated the value of an offer to acquire the Arcata Corporation. The offer, accepted by Arcata's board, was valued at $335 million.

Demolition of the Morosco and Helen Hayes Theaters began yesterday after the United States Supreme Court lifted a temporary stay and removed the last major impediment to construction of the 50-story Portman Hotel in the Times Square area. The high court's order was handed down shortly after 10 A.M. but about 170 demonstrators prevented work crews from beginning demolition work immediately. The protesters, including some prominent Broadway performers, demonstrated in an empty lot adjoining the Morosco on West 45th Street. By prior arrangement with the police, they were arrested and taken away in 13 police vans. Just after 2 P.M., a huge hydraulic backhoe, with the name Godzilla on its side, thrust its steel jaws into the remaining wall of the Bijou, a theater that until two weeks ago had stood next to the Morosco, and pulled it down. Then, while the crowd shouted ''Don't do it! Don't do it!'' the machine bit into the east wall of the Morosco and tore out a gaping hole.

International Washington accused Moscow and its allies in Southeast Asia of having used toxins and chemical warfare agents in Laos, Cambodia and Afghanistan. The Reagan Administration presented a 32-page report detailing evidence for its accusation that more than 10,000 people had died as a result of nearly 400 chemical warfare attacks carried out in the three countries since 1975. (Page A1, Column 4.) A Palestinian teen-ager was slain and two other Arabs were wounded as the Israeli army continued to use gunfire to suppress violent demonstrations throughout the West Bank. A general strike continued for a fourth day in protest over the Government's ouster of an elected town council. (A1:3-5.)

THE Supreme Court of the United States is scheduled to hear oral arguments today in the case of Amy Rowley, a deaf fourth grader from Peekskill, N.Y., to decide whether public school systems may be required to provide sign language interpreters in the classroom. Educators across the nation are looking to the case for a definition of what Congress meant in 1975 when it passed a law requiring all school districts to provide a ''free appropriate public education'' to handicapped children. Does an ''appropriate'' education mean one that enables a child to become, as a Federal District Court posed the issue, ''a functioning member of society''? Or does it mean giving a handicapped child such as Amy, who had been performing in the top half of her class when her parents requested an interpreter, what the court called ''an opportunity to achieve his full potential''? The case comes when educators throughout the nation are grappling with the practical implications of the law, the Education for All Handicapped Children Act, which called for sweeping changes in the instruction of handicapped children, who have been long neglected by school systems.

Yale University declined a $30,000 Federal grant yesterday, saying it would not comply with a Federal rule that a professor account for the use of his time. The decision by Charles Bockelman, deputy provost, is the first time that a university has turned down Federal support for research because of the accounting rule, according to officials of the National Science Foundation and the American Association of Universities. Yale's action follows 16 years of sporadic conflict between universities and the Government about the rule . At issue is $4.77 billion in annual Federal support for research.

The Japanese subway cars that will soon replace the antiquated cars on the Broad Street line here have proved to be quick, safe and efficient, but a bit noisy, according to preliminary tests. The Philadelphia cars are similar, but not identical, to the ones that New York's Metropolitan Transportation Authority recently decided to buy from the same Japanese company, Kawasaki Heavy Industries Ltd. A public hearing on the New York car purchase will be held Tuesday at the headquarters of the M.T.A. at 347 Madison Avenue, at 44th Street. Final approval of the $274.4 million sale is expected at a board meeting that will follow.