Alasiri (kutoka Kiarabu) ni kipindi cha mchana kati ya adhuhuri na jioni, wakati ukali wa mwanga wa jua unapozidi kupungua. Kwa kawaida wakati huo kwa binadamu unafuata mlo: hivyo utendaji wake unapungua pamoja na umakinifu wake. Ndiyo sababu ajali nyingi huwa zinatokea wakati huo. Dini mbalimbali zenye ratiba ya sala, kwa mfano Ukristo na Uislamu, zina kipindi maalumu kwa alasiri. Aggarwal, Anjali (2013). Heat Stress and Animal Productivity. Springer Publishing. ISBN 978-8-132-20879-2.  Blaskovich, Jim (2011). Social Psychophysiology for Social and Personality Psychology. ISBN 978-0-85702-405-3.  Ekirch, A. Roger (2006). At Day's Close: Night in Times Past. W. W. Norton & Company. ISBN 978-0-393-32901-8.  McCabe, Paul T. (2004). Contemporary Ergonomics. CRC Press. ISBN 0-8493-2342-8.  Ray, James T. (1960). Human Performance as a Function of the Work–Rest Cycle. National Academy of Sciences.  Refinetti, Roberto (2006). Circadian Physiology, 2nd, Taylor & Francis Group. ISBN 978-0-8493-2233-4.  Sinclair, Thomas M. (2010). Principles of Ecology in Plant Production. University of Nebraska, Lincoln/University of Florida.  Wikimedia Commons ina media kuhusu: Alasiri