A Correction of the Termination Conditions of the Henschen-Naqvi Technique

Henschen and Naqvi described a technique for translating queries on recursively defined relations of a Datalog database into iterative programs that invoke a query processor for conventional select-project-join queries of the relational algebra. Although the technique has been cited as one of the most efficient available, it will in some cases fail to produce all answers defined by the usual semantics for such databases. The technique is reviewed, a recursive query is exhibited where it fails, the cause of failure is noted, and a correction is described. A graphical representation of the computation based on a formal representation of rule expansions is employed

Studies related to the process of program development

The submitted work consists of a collection of publications arising from research carried out at Rhodes University (1970-1980) and at Heriot-Watt University (1980-1992). The theme of this research is the process of program development, i.e. the process of creating a computer program to solve some particular problem. The papers presented cover a number of different topics which relate to this process, viz. (a) Programming methodology programming. (b) Properties of programming languages. aspects of structured. (c) Formal specification of programming languages. (d) Compiler techniques. (e) Declarative programming languages. (f) Program development aids. (g) Automatic program generation. (h) Databases. (i) Algorithms and applications

Hypothyroidism

Hypothyroidism is the most common thyroid disorder and it is significantly more frequent than presented - millions of people suffer from this disease without knowing it. People with this condition will have symptoms associated with slow metabolism. Estimates of subclinical hypothyroidism range between 3 to 8 %, increasing with age, whereas it more likely affects women than men. About 10% of women may have some degree of thyroid hormone deficiency. Hypothyroidism may affect lipid metabolism, neurological diseases or other clinical conditions. The book includes studies on advancements in diagnosis, regulation and replacement therapy, thyroid ultrasonography and radioiodine therapy for hypothyroidism. "Hypothyroidism - Influences and Treatments" contains many important specifications, results of scientific studies and innovations for endocrine practice