Day level:	yij (nostalgia) = β0j + β1j (past) + β2j (present) + β3j (future) + β4j (time) + rij
Person level:	${\text{β}}_{\text{0j}}={\text{γ}}_{\text{00}}+u_{0j}$
	${\text{β}}_{\text{1j}}={\text{γ}}_{\text{10}}+u_{1j}$
	${\text{β}}_{\text{2j}}={\text{γ}}_{\text{20}}+u_{2j}$
	${\text{β}}_{\text{3j}}={\text{γ}}_{\text{30}}+u_{3j}$
	${\text{β}}_{\text{4j}}={\text{γ}}_{\text{40}}+u_{4j}$