February 16, 1986

EMACIATED and too weak to walk alone, 20-year-old Yvonne lies in Jersey City Medical Center, slowly dying of AIDS. This is her third admission since last May; she once stayed three months. Yvonne now receives intravenous medications for a painful fungal infection in her mouth and throat, drugs for herpes and a tuberculosis-like infection, a special diet and bedside physical therapy. Across the hall is James, 29, a 6-foot 2-inch AIDS patient whose weight has fallen to 110 pounds. Last November, he was hospitalized for two months with pneumonia, fungal infections, periodic fevers and a low white-blood-cell count.

CONSTRUCTION has begun on the long-awaited redevelopment of the oceanfront here amid expectations that it will spur efforts to revitalize the city, which is showing signs of rebirth after years of decline. A mile-long stretch of Ocean Avenue just below Seven Presidents Park is being converted into a landscaped pedestrian mall and promenade that will have areas for joggers, bicyclists and strollers. Benches, with views of the ocean, will line the promenade. Construction began in January, and Anthony Muscillo, the city's Business Administrator, said he expected it to be completed early next year. (During construction, traffic will be rerouted to the newly completed extension of Ocean Boulevard, a four-lane highway just to the west.) The $1.5 million project is being financed through the state's Green Acres program.

Realty Research Properties broke ground last month on the first stage of a 150,000 square foot shopping center on a site it has owned in Washington Township for 10 years. What made the developer go ahead was the signing of an anchor tenant, Mayfair Foodtown, the New Jersey chain, to occupy 38,000 square feet, according to Robert Bartnett, vice president of Realty Research Properties of Morristown, N.J..

Scratch any operagoer and you will find a casting expert. This remarkable person has only to get on the phone for a moment with Madame X and Mr. Y to nail down those eminent singers to commitments insuring their presence at the Metropolitan throughout their prime years and perhaps a few more. Without knowing or caring much about the logistical problems that confront the officials actually in charge of filling opera casts, the fan is easily able to conjure up dream productions of his favorite works. Managers of the world's most renowned artists sit by their telephones night and day waiting for the casting expert's call.

ARCTIC DREAMS Imagination and Desire in a Northern Landscape. By Barry Lopez. Maps. 464 pp. New York: Charles Scribner's Sons. $22.95. IF you lowered a microphone into Lancaster Sound off Baffin Island in the Canadian Arctic on a summer day, you might hear all at once the tremolo moans of bearded seals, the baritone boom of a walrus, the high-pitched bark and yelp of ringed seals, the electric crackling of shrimp, the birdlike trills and clicks and other harmonics of white beluga whales and horned narwhals, and the elephantine trumpeting of huge bowhead whales. And it is this synchronous wealth of life - of all life - that Barry Lopez is celebrating in his jubilant new book. Among contemporary nature writers Mr. Lopez is especially a rhapsodist, and what he has done in this passionate paean to the Arctic and its cycles of light and darkness, its species of ice, its creatures and waters, is to present a whole series of raptures and riffs on the subject of musk oxen, ivory gulls, white foxes, polar bears, icebergs and sea cur-rents. Speaking of the effect of the Arctic upon an explorer, he describes how ''the land becomes large, alive like an animal; it humbles him. . . . It is not that the land is simply beautiful but that it is powerful. . . . Darkness and light are bound together within it, and the feeling that this is the floor of creation.''