In each male, the following testicular lesions were scored: (1) hemocytic infiltration of the gonadal acini and phagocytosis of spermatogenic cells, (2) hemocytic infiltration of interacinal connective tissue, (3) aggregations of hemocytes under the mantle epithelium, and (4) occurrence of brown cells.
For example: a long exposure refers to a single, protracted shutter cycle to capture enough low-intensity light, whereas a multiple exposure involves a series of relatively brief shutter cycles; effectively layering a series of photographs in one image.
When you see those exposures that cover long periods of time (minutes - hours) they are using a timer (like the Canon Timer Remote Controller TC-80N3). It allows you to set exposure times up to 99 hours, 59 minutes, and 59 seconds.