is at least ae powerful as SQL. Two well known relational query languages that have a sound theoretical foundation are relational algebra and relational calculus. As SQL is more closely related to relational calculus, we define the semantics of SQL by translation into calculus. However, relational calculus has to be extended in order to deal with aggregate functions and null values. The op timi...

OBJECTIVE To assess the relationship between periodontal treatment needs by elderly Brazilians and contextual as well as individual variables. METHODS A cross-sectional study was carried out to assess the need for clinical periodontal treatment, based on National Oral Health Survey (SB Brasil 2010) data on the presence of dental calculus, shallow (3-5 mm) and deep (≥ 6 mm) periodontal pockets...

Using the Malliavin calculus, we give a uniied treatment of the so-called perturbation analysis of dynamic systems. Several applications are also given.