does not use soil to grow fish and vegetables, thus completely alleviating the radiophobia surrounding food that always follows long-lived contamination incidents. Others who have approached the food problem from a far more extreme view, assuming far worse events such as comet impacts, as discussed in the book Feeding Everyone No Matter What, have suggested; natural-gas-digesting bacteria the most well known being methylococcus capsulatus, that is presently used as a feed in fish farming, Bark bread a long-standing famine food using the edible inner bark of trees once a part of Scandinavian history during the Little Ice Age and the expansion of leaf protein concentrate and larger scale wood digesting fungiculture for fungal protein, with the most common of which being shiitake mushrooms and honey fungi, as they do not need sunlight or soil to grow. More advanced techniques mentioned, that are not presently economical also include variations of wood or cellulosic biofuel production, which typically already creates edible sugars/xylitol from inedible cellulose, as an intermediate product before the final step of alcohol generation. Historical and psychological assessment Some historians and filmmakers, exemplified by the 1982 The Atomic Cafe, have thus far sought to dismiss civil defense advice as mere propaganda, despite, as other historians have found, detailed scientific research programs behind the much-mocked government civil defense pamphlets of the 1950s and 1960s, including the prompt advice of ducking and covering. In U.S. Army training, soldiers are taught to immediately fall down, covering face and hands in much the same way as is described by the advice to duck and cover. The exercises of Cold War civil defense are seen by historian Guy Oakes in 1994, as having less practical use than psychological use: to keep the danger of nuclear war high on the public mind, while also attempting to assure the American people that something could be done to defend against nuclear attack. Moreover, civil defense was not solely a US-UK or nuclear club phenomenon; countries with long histories of neutrality, such as Switzerland, are "foremost in their civil defence precautions." The Swiss civil defense network has an overcapacity of nuclear fallout shelters for the country's population size, and by law, new homes must still be built with a fallout shelter as of 2011. Tornadoes Ducking and covering does have certain applications in other, more natural disasters. In states prone to tornadoes, school children are urged to "duck and