Various structural elements have construction methods and potential problems that deserve attention. Points of note include: the ‘ratchet effect’ on rubble-filled walls of repeated freezing and thawing; the possibility of mortar shrinkage or of stone decay through excessive stress; the crucial role of crossing piers which carry a tower, and how they can be strengthened (as at Milan and Worcester); the (maybe counterintuitive) structural contribution of pinnacles; the detailed actions of flying buttresses, and how they may fail (as at Amiens) if they are not ‘flat arches’; the importance of binding ribs to walls by single ‘through-stones’; how stone windows handle thrusts from the wall above and wind outside, starting with rectangular windows and moving on to rose windows; and the actions in response to live and dead loads on cantilevered stone stairs, whether piecewise straight with corner landings or geometrical (as in a round tower). Calculations about structural actions (of flying buttresses, stone windows and stone stairs) can be based on simple statics.

This chapter describes Psychosis Identification and Early Referral (PIER), a clinical and public health system for identifying, treating, and rehabilitating young people at risk for major psychosis and psychotic disorders. A specialized clinical team educates key sectors of the community in identifying very early signs and symptoms of a likely psychosis in youth ages 10–25. The team then rigorously assesses those referred and found at risk and provides family-aided assertive community treatment. This model was originally developed for schizophrenia in young adults, and it has been adapted for the much younger and less seriously symptomatic and disabled at-risk population. The model includes flexible, in-vivo clinical treatment, family psychoeducation, cognitive-behavioral therapy, occupational therapy, supported education and supported employment, and psychiatric and nursing care. PIER has been tested across six population-representative sites in the United States; within testing periods, very few participating youths have experienced psychosis and about 90 percent are in school or working. It has been replicated widely enough that it is available to over 15 percent of the US population.