3,136 research outputs found
Topology on the Lattice
We review the method developed in Pisa to determine the topological
susceptibility in lattice QCD and present a collection of new and old results
obtained by the method.Comment: 10 pages, 7 figures. Contribution to "Sense of Beauty in Physics - a
volume in honour of Adriano Di Giacomo" (Pisa University Press, Pisa, 2006),
on the occasion of his 70th birthda
Oxidation of glucose by iodine in the presence of insulin
This investigation was undertaken with the purpose of determining whether insulin, alone or in the presence of certain animal fluids, has any influence upon glucose in vitro. The establishment of such an influence might have much significance in relation both to the study of carbohydrate metabolism and to the development of methods of assaying insulin
Inhibitor specificity of amine oxidase
Although at the present time it appears clear that amine oxidase oxidation of adrenalin, or other o-diphenolic pressor amines such as were studied by Richter (6), does not play a significant physiological role, it is equally clear that the inactivation of aliphatic amines, phenethylamine and probably 4-hydroxyphenethylamine (tyramine), does predominantly take place by amine oxidase oxidation. In view of the evidence from the experiments of Ewins and Laidlaw (8) and a later study by Guggenheim and Löffler (9), such amine oxidations chiefly occur in the liver. In the present studies, an attempt was made to value quantitatively the inhibition of some of these particular type compounds by certain types of amines which are not themselves oxidized by the enzyme system (see Alles and Heegaard (10))
Substrate specificity of amine oxidase
The tyramine oxidase activity of liver extracts found by Hare (1), the aliphatic amine oxidase activity of brain, kidney, and liver extracts observed by Pugh and Quastel (2), and the adrenalin oxidase activity of similar extracts noted by Blaschko, Richter, and Schlossman (3) were brought under a common enzyme view-point by the latter authors. They were able to show (4) that extracts of brain, instestine, kindey, and liver from a number of mammals or representatives of the birds, reptiles, amphibians, and fishes all acted to absorb oxygen in the presence of several amine substrates. Hare (1) had shown that tyramine and phenethylamine form ammonia in the course of such oxidations, and Richter (5) showed that an ethylamino and a dimethylamino compound, as well as a number of methylamino and amino compounds, all yield the corresponding alkyl-amines or ammonia in the enzymic oxidation.
The conslusion that the demonstrated variey of such enzymic activity can be acribed to the presence of a single type pf amine oxidase was dependent in large part on observations that the relative activities of a preparation from one source on a series of substrates bear some relation to the relative activities exhibited by a preparation from another source. Further evidence depended on the action of certain amines as inihibitors and apparent competition between substrates when two oxidizable substrates are present in the system. The degree to which relative activities of different enzyme preparations were constant in a series of substrates was not good in the data reported, and the fact that Hare (1) had not been able to note activity of the liver preparations she used upon adrenalin as the substrate appeared to require special explanations
The opportunity economy : enduring lessons from the ride and fall of the new economy
In this paper we argue that the business model underlying the new economy is based on the following interrelated and self-reinforcing forces: 1. The development of a new strategy of opportunity, which focuses on the use of creative innovation to open up new market spaces, rather than using exploitive innovation to prolong the life of existing products. 2. The democratization of competition thanks to the Internet and to process outsourcing. 3. Taken together, these forces result in a profound shift in the source of value creation in firms from processes and physical assets to people. With the drivers of business success so fundamentally transformed, almost all aspects of the firm and its management also need to change, from valuation, resource allocation and worker compensation, to what it takes to retain workers and promote innovation. But while the rules of business have changed, there has not been a corresponding shift in awareness among most managers. Assuming that there is nothing new in the New Economy is a profound and dangerous mistake. Managers that are so short sighted will find that they have not only lost out on the opportunities that the new economy continues to provide, but that the market downturn has only deferred, rather than eliminated, the threats that change poses to their firms.En este artículo debatimos que el sistema de comercio subyacente en la nueva economía está basado en las siguientes fuerzas interrelacionadas entre si, y que se auto refuerzan: 1. El desarrollo de una nueva estrategia de oportunidades, la cual se enfoca en el uso de la innovación creativa como forma de abrir nuevos espacios de mercado en lugar de usar una innovación explotadora para prolongar la vida de los productos existentes. 2. La democratización de la competición gracias al internet y al proceso de búsqueda externa. 3. En conjunto, estas fuerzas desembocan en una profunda brecha en la fuente del valor de creación en las firmas de los procesos y la asistencia física a las personas. Con los conductores de los éxitos de negocios transformados de manera tan fundamental, casi todos los aspectos de la firma y su gestión también necesitan cambiar, de la valoración, asignación de recursos y compensación a los trabajadores, a lo que requiere mantener a los trabajadores en plantilla y promover la innovación. Pero mientras las reglas de los negocios han cambiado, no ha habido un ajuste correspondiente entre la concienciación de la mayoría de los managers. Asumir que no hay nada nuevo en la Nueva Economía es un error tremendo y peligroso. Los managers tan cerrados de miras encontrarán que no sólo han perdido las oportunidades que la nueva economía sigue proporcionando, sino que también, pero que la desaceleración del mercado sólo ha aplazado, en lugar de eliminar, las amenazas que el cambio plantea a sus empresas
- …