Prevent aggravation of canker sores by avoiding: 1  Abrasive foods or those that can stick in the mouth (potato chips, for example) 2  Spicy, acidic, or hot foods and drinks.  Traumatizing the ulcers (through harsh contact with toothbrush bristles, for example).
A new species of spider -- Cerbalus aravensis -- is the largest of its type in the Middle East, scientists in Israel say. Credit: Photo by Yael Olek, courtesy of the University of Haifa.
The genus contains 31 recognized species distributed worldwide, including the North American black widows (L. mactans, L. hesperus, and L. variolus), the button spiders of Africa, and the Australian redback spider. Species vary widely in size.