A retrospective study was conducted of 91 boys who had had a non-retractable but non-fibrosed prepuce treated by retraction under general anaesthesia. Of the 79 boys who had had symptoms, 67 (85%) obtained relief. Twelve of the 91 patients were later circumcised because of continuing problems. Retraction of the foreskin alone is a simple and effective alternative to circumcision in managing mos...

Vigorous plant growth without sunlight is routinely achieved in commercial hydroponic lettuce and tomato production using electric lamps. This same technology can be used to maintain live turf grass in closed athletic stadiums. It can also be used to supplement natural sunlight in retractable roof stadiums. The challenge is to determine the optimal combination of genetic characteristics and env...

An automaton A is called a retractable automaton if, for every subau-tomaton B of A, there is at least one homomorphism of A onto B which leaves the elements of B fixed (such homomorphism is called a retract ho-momorphism of A onto B). We say that a retractable automaton A=(A,X,δ) is Boolean-type if there exists a family {λ B | B is a subautomaton of A} of retract homomorphisms λ B of A such th...

Retractable type fall arresters constitute a most effective group of components used in personal protection systems protecting against falls from a height. They are designed primarily for outdoor use, which results in exposure to atmospheric factors associated with risk of corrosion of metal elements. This paper presents the results of a study, in which retractable type fall arresters were expo...

In calculi for modelling communication protocols, internal and external choices play dual roles. Two external choices can be viewed naturally as dual too, as they represent an agreement between the communicating parties. If the interaction fails, the past agreements are good candidates as points where to roll back, in order to take a different agreement. We propose a variant of contracts with s...

This is a survey on the usage of the module theoretic notion of a “retractable module" in the study of algebras with actions. We explain how classical results can be interpreted using module theory and end the paper with some open questions.

Abstract This paper by reviewing the main examples of small to medium-scale retractable roof structures covering building courtyards is to present an innovative rigid retractable roof system employing spatial frames for a courtyard of an existing building in Tabriz Islamic Art University. The courtyard is currently used for temporary exhibitions and gatherings whenever permitted by environmenta...