The concept of free as in "free group" is generalized to any first order theory. An interesting class of homomorphisms between models is discussed. Relations between model theory and abelian categories are discussed speculatively. This paper represents an incomplete study…

A program, some TECO macros, and some small modifications to existing systems software have been written, called PRO, whose purpose is to reduce the large number of control languages and system programs it has been necessary to know about and…

El Espacio Europeo de Educación Superior revitaliza la competencia tutorial como uno de los ejes nucleares sobre los que debe sustentarse la actividad docente. Para satisfacer y cumplir los derechos y los deberes de alumnos y profesores, en materia de…

En lo referente al entretenimiento, la ciudad de Quito no cuenta con bares especializados; ya que en todos se puede encontrar una gran variedad de cócteles y licores fuertes; sin embargo existe una variedad de 3 – 4 marcas de…

A notable contribution to the knowledge of relative incidence and cause of mortality in pigs was made by an extensive survey carried out by the Ministry of Agriculture, Fisheries and Food, Veterinary Investigation Service in England. [...]

The following information, as revealed in these studies, is claimed to be a contribution to knowledge. A bacterium and a fungus identified as a Pseudomonas sp. and a Penicillium sp. were isolated by the soil perfusion enrichment technique, and are…

Chemical reactions involve ordinarily the breaking of bonds in the reacting molecules and the formation of bonds in the products; they are usually accompanied by changes in enthalpy. Although the stability of a molecule or a radical, as expressed in…

The aim of Historical Geography is essentially twofold - the elucidation of the present geographical reality of an area by the fuller understanding of its past development, and the attainment of some knowledge of the processes of geographical change. Most…

In establishing the range of an Historical Geography it is often wise, for the sake of clarity, to outline those things which are not within the scope of a particular work as well as its actual aim. It is not…

The aim of this thesis is to study the behaviour of the money supply of Trinidad and Tobago during the period from 1797 to 1964, and to relate it to the economic development of the country. No attempt will be…