LOS ANGELES—Amid a surge in COIVD-19 cases, almost one-third of students were absent on Jan. 11, the first day of the spring semester in the Los Angeles Unified School District (LAUSD). The district serves over 600,000 students, of whom 30 percent—about 180,000—did not go back to school on Tuesday, mostly because of testing positive or experiencing technical issues when uploading their test results to the district’s Daily Pass mobile application. All LAUSD students and staff must upload proof of a negative COVID-19 test result to the Daily Pass app to return to campus, as required by the district on Jan. 3. As of Jan. 11, about 88 percent of students and 91 percent of employees have uploaded their test results to Daily Pass before in-person instruction restarted, according to the district. Seventeen percent of students uploaded positive results while 12 percent did not upload any results, leaving about 1 percent …