The pressure in closed conditions conforms with the principles of fluid dynamics. The concepts of fluid pressure are predominantly attributed to the discoveries of Blaise Pascal and Daniel Bernoulli. Bernoullis equation can be used in almost any situation to determine the pressure at any point in a fluid. The equation makes some assumptions about the fluid, such as the fluid being ideal and incompressible. An ideal fluid is a fluid in which there is no friction, it is inviscid (zero viscosity).
It is very common for psychological disorders to overlap and even lead to the manifestation of another, especially when it comes to anxiety disorders. Because of the variation and overlap in symptoms a proper, thorough evaluation of the individual is critical to distinguish the differences and significance. An important signifier to establish a difference between SAD and other anxiety or psychological disorders is to investigate where the individuals fear of separation is stemming from; this can be accomplished by asking "what they fear will occur during a separation from their significant other".What stands out about SAD, as mentioned above, are the avoidance behaviors which present within an individual. Individuals "typically exhibit excessive distress manifested by crying, repeated complaints of physical symptoms (e.g., stomach aches, headaches, etc. ), avoidance (e.g., refusing to go to school, to sleep alone, to be left alone in the home, to engage in social events, to go to work, etc. ), and engagement in safety behaviors (e.g., frequent calls to or from significant others, or primary caregivers)". Assessment methods
Assessment methods include diagnostic interviews, self-report measures from both the parent and child, observation of parent-child interaction, and specialized assessment for preschool-aged children. Various facets of a childs development including social life, feeding and sleep schedules, medical issues, traumatic events experienced, family history of mental or anxiety health issues are explored.