Many factors, both genetic and environmental, have been blamed for increasing the risk of a diagnosis of schizophrenia. Some, such as a family history of schizophrenia, are widely accepted. Others, such as infection with Toxoplasma gondii, a parasite transmitted by soil, undercooked meat and cat feces, are still viewed with skepticism. A new study used epidemiological modeling methods to determine the proportion of schizophrenia cases that may be attributable to T. gondii infection. The work suggests that about one-fifth of cases may involve the parasite.
Unable to fly, nestling birds depend on their parents for both food and protection: vocal communication between parents and offspring helps young birds to determine when they should beg for food and when they should crouch in the nest to avoid a predator seeking an easy meal. A group of researchers has found that ambient, anthropomorphic noise -- from traffic, construction and other human activities -- can break this vital communications link, leaving nestlings vulnerable or hungry.
Sea trout, also known as brown trout, live complicated lives. Like salmon, they begin their lives in a river, hatched from eggs that were laid in small nests, called redds. As the young fish mature, they go through several developmental stages, all of which involve substantial physiological changes. The most important stage from this perspective is when the fish becomes a smolt, after about 2 years. Entering the smolt stage is like being given a passport out to the sea, because the physiological changes allow the fish to tolerate salt water.