Finding significant the fact that a nurse "cannot cause a nurse's aide to be fired by giving her a poor evaluation or cause her to be promoted by giving her a superlative evaluation"
Finding evidence insufficient to show that nurses played a supervisory role where they only reported to others who made the actual disciplinary decisions
Holding that LPNs' authority to assign work to aides did not involve independent judgement where authority to assign work to aides simply involved following management's policy and procedure
Holding that "[b]ecause of the Board's `special competence' in the field of labor relations, its interpretation of the Act is accorded special deference" and noting that "[w]hether a [bargaining] unit is appropriate involves a large measure of informed discretion vested in the Board and is rarely to be disturbed"