107 Mental Health Residential Treatment Center means a facility that meets all of the tests of the Acute Care Hospital definition or it is licensed in accordance with the laws of the appropriate legally a uthorized agency as a residential treatment center for Mental Health Services . Nurse means only a person who is a registered Nurse (R.N.), a licensed vocational Nurse (L.V.N.), or a licensed practical Nurse (L.P.N.). Partial Hospitalization Care means only continuous treatment of substance abuse or of a mental, nervous or emotional disorder or condition for at least 4 hours, but not more than 12 hours, in an y 24 - hour period. Participant means a person who is eligibl e for benefits under the Plan. Participat ion Agreement means the agreement providi ng for coverage under the Plan. Payment Percentage means the percentage the Plan pays of a covered medical charge after any applicable deductible is satisfied. Physician means a doctor of medicine or a doctor of ost eopathy who is licensed by his jurisdiction and acting within the scope of his license to practice medicine or to perform surgery. Plan means the National I AM Benefit Trust Fund. Preferred Provider Organization means an organization that negotiates discoun ted rates with medical providers in an effort to provide benefits to participant s. Preferred Provider means a provider that enters into an agreement with the Preferred Provider Organization to provide service s at negotiated discount rates. Pregnancy means any Pregnancy, a complication thereof, or the termination of a Pregnancy. Pregnancy benefits are payable on the same basis as benefits for treatment of an illness . Professionally Recognized Standards means professionally recognized standards of quality, a s determined by the Trustees, or their delegates. To determine such standards, the Fund Office may use such groups as: The American Medical Association; The American Dental Association; their affiliates and successors; peer review groups; professional rev i ew groups; and similar groups. Retiree means a person who formerly qualified as an Employee, who has retired from active employment while covered by this Plan, and on whose behalf the Employer continues to make the required contributions to the Plan, but o nly if the particular coll ective bargaining agreement or p articipation a greement allow for Retiree coverage. Skilled Nursing Facility and Rehabilitation Hospital each mean only an institution that meets all of the following tests: • It mainly provides skill ed nursing care or rehabilitation care to registered inpatients; • It provides care that is supervised, 24 hours per day, by a physician or registered Nurse; • It has available at all times a physician who is a staff member of an Acute Care Hospital; • It has a registered Nurse, licensed vocational Nurse, or licensed practical Nurse on duty 24 hours per day and has a registered Nurse on duty at least eight hours per day; • It maintains a daily medical record for each patient; • It complies with all licensing and ot her legal requirements; • It is not a Specialized Facility; and