chemotaxis of rhizobium phaseoli towards flavones and other related compounds

The formation of nitrogen-fixing nodules on leguminous plants is the result of a highly specific interaction between the host plant and the soil bacterium Rhizobium. Two observations suggest that chemotaxis may play a role in the establishment of the legume-Rhizobium symbiosis: 1) The widespread occurence of Rhizobium species with flagella (Gotz, 1982; Carlile. 1980)2) The copious exudation into the soil surrounding legume roots of a wide variety of potentially chemotactic compounds which include amino acids, sugars and sugar-acids. (Beringer et.al.,1979). Recently the plant flavones luteolin (3,44,7 - Tetra - hydroxyflavone) and apigenin (4,5,7 - Trihydroxy-flavone) have been reported as inducers of Rhizobium nodulation genes (Peters, 1986, Rolfe 1986). We report here that R. phaseoli (RP8002) exhibits positive chemotaxis toward both flavones. Other diverse compounds tested elicited different responses. An understanding of the influence of flavones in two events such as chemotaxis and nodulation efficiency can be valuable to clarify their action in the intricate legume-rhizobia interaction

Origins of permanent revolution theory: the formation of Marxism as a tradition (1865-1895) and 'the first Trotsky'. Introductory dimensions

Investigating the period of emergence of Marxism as a tradition between 1865 and 1895, this work examines some key questions elucidating Trotsky's theoretical developments during the first decade of the XXth century. Emphasizing the role of such authors like Plekhanov, Johann Baptists von Schweitzer, Lenin and Zetkin in the developing of a 'Classical Marxism' that served as the foundation of the first formulation of Trotsky's theory of permanent revolution, it treats three introductory dimensions of this larger problematic: primitive communism and its feminist implications, the debate on the relations between the productive forces and the relations of production, and the first apprehensions of Marx's economic mature works

Extended Hamiltonian systems in multisymplectic field theories

We consider Hamiltonian systems in first-order multisymplectic field theories. We review the properties of Hamiltonian systems in the so-called restricted multimomentum bundle, including the variational principle which leads to the Hamiltonian field equations. In an analogous way to how these systems are defined in the so-called extended (symplectic) formulation of non-autonomous mechanics, we introduce Hamiltonian systems in the extended multimomentum bundle. The geometric properties of these systems are studied, the Hamiltonian equations are analyzed using integrable multivector fields, the corresponding variational principle is also stated, and the relation between the extended and the restricted Hamiltonian systems is established. All these properties are also adapted to certain kinds of submanifolds of the multimomentum bundles in order to cover the case of almost-regular field theories.Comment: 36 pp. The introduction and the abstract have been rewritten. New references are added and some little mistakes are corrected. The title has been slightly modifie

Relational Galois connections between transitive fuzzy digraphs

Fuzzy-directed graphs are often chosen as the data structure to model and implement solutions to several problems in the applied sciences. Galois connections have also shown to be useful both in theoretical and in practical problems. In this paper, the notion of relational Galois connection is extended to be applied between transitive fuzzy directed graphs. In this framework, the components of the connection are crisp relations satisfying certain reasonable properties given in terms of the so-called full powering

Continuous Cauchy wavelet transform of XAFS spectra.

The continuous Cauchy wavelet transform (CCWT) is applied to the analysis of XAFS spectra. Thanks to that method, XANES and EXAFS signals can be visualized in threedimension: the wavevector (k), the interatomic distance uncorrected for phase-shifts (R') and the CCWT modulus (corresponding to the continuous decomposition of the amplitude terms). Applied to EXAFS spectra, the CCWT analysis provides straightforward qualitative information related to the k-range of each “R'-EXAFS” contribution. Such information is particularly useful to perform next nearest-neighbors identification, despite the presence of spectral artifacts such as multiple-scattering features, multi-electronic excitations or noise. When applied to XANES spectra, the CCWT analysis helps highly to measure the “spectral limit” between XANES and EXAFS regions, as well as the energy range required to model properly next-nearest neighbors. To further illustrate the potential of CCWT analyses applied to XAFS spectra, we present examples related to: (1) a XANES spectrum collected at the Ti K-edge for titanite (CaTiSiO5); (2) an experimental Au LIII-edge EXAFS spectrum for gold sorbed on goethite (FeO(OH))

Continuous Cauchy wavelet transform analyses of EXAFS spectra: A qualitative approach.

To better understand the extended x-ray absorption fine structure (EXAFS) spectroscopic information obtained for complex materials such as those encountered in Earth sciences, we propose to use the Continuous Cauchy Wavelet Transform (CCWT). Thanks to this method, the EXAFS spectra can be visualized in three-dimension: the wavevector (k), the interatomic distance uncorrected for phase-shifts (R') and the CCWT modulus (corresponding to the continuous decomposition of the EXAFS amplitude terms). Consequently, more straightforward qualitative interpretations of EXAFS spectra can be performed, even when spectral artifacts are present, such as multiple-scattering features, multi-electronic excitations or noise. More particularly, this method provides important information concerning the krange of each EXAFS contribution, such as next nearest-neighbors identification. To illustrate the potential of CCWT analyses applied to EXAFS spectra, we present first the experimental and theoretical spectra obtained for well-crystallized minerals, thorite and zircon, at the Th LIII-, and Zr K-edges, respectively. Then, we present the CCWT analyses of EXAFS spectra collected for amorphous materials of geochemical and environmental interests, including a sodium trisilicate glass and an aqueous chloride solution, at the Mo K-, and Au LIII-edges, respectively

European Clearinghouse: Nuclear Power Plants Decommissioning Related Events

Decommissioning is the final phase in the life cycle of an installation. The term decommissioning refers to administrative and technical actions taken to allow removal of some or all of the regulatory controls from a nuclear facility. It is an integral process that involves complex and diverse operations as well as several stakeholders and regulatory organisations. Regardless of its complexity and its cost, suitable strategies and techniques for the decommissioning of nuclear power plants are available, and have been successfully applied in many sites. However, the operative experience could be better collected, and the lessons learned should be shared as their equivalents of the operational phase. This is a major issue considering the large number of NPP that are in this phase, or are close to their shutdown. This Summary Report presents the results of a study performed by the European Clearinghouse on Operating Experience Feedback of NPP about events related to decommissioning.JRC.F.5-Nuclear Reactor Safety Assessmen

Enhanced Learning Using Mutimedia-Interactive Systems: An Experimental Study

The education field is in a process of change driven by new developments in multimedia technology, which is being used as a complementary alternative for teaching purposes. This paper describes a thesis project developed through an exploratory study comparing the effects of using three different teaching approaches: traditional teacher-led instruction, web page instruction and a multimedia-interactive system. The principal objective is to find out whether the use of a prototype multimedia-interactive delivers better outcomes in teaching complex subjects such as data structures, than web page and traditional teacher-led instruction approaches. Information Systems Design Theory was used to develop a multimediainteractive tool. Students were taught to use binary trees to compare the three teaching methods. Pilot test results show that there are significant differences in performance of students who used the multimedia-interactive tool. It is concluded that the multimedia-interactive system prototype can effectively be used to help students learn binary trees

Generacion de energia electrica para una casa rural

106 p.La presente memoria trata sobre la necesidad de dotar de energía eléctrica a una casa ubicada en un sector rural, específicamente en la localidad de BRISAS DEL MAIPO, ubica a orilla del río Maipo en sector de Rinconada de San Juan, San Antonio, V región. Este lugar no se encuentra muy habitado, una de estas razones es la falta de comodidades, tales como agua potable, alcantarillado y energía eléctrica. El agua potable y el alcantarillado se podrían adquirir, pero con un gran costo al tener que conectarse al sistema interconectado, lo que lo hace inviable a corto plazo. La energía eléctrica también sería de gran costo, pero se puede obtener de diferentes formas, una de estas es la que muestra este trabajo, que es por medio de la energía hidráulica. Como este sector no cuenta con tendido eléctrico, se pretende obtener energía eléctrica a través del aprovechamiento de la energía que posee el río Maipo, para esto se mostrarán distintas alternativas de producción de energía eléctrica a través de energía renovables. La energía cinética del río Maipo se transformará en energía mecánica por medio de la turbina, energía mecánica que se transformará en energía eléctrica a través de un alternador de automóvil, energía que será almacenada en baterías de plomo. Esta turbina hidráulica será diseñada con tambores metálicos de 30 galones, los cuales al ser cortados por la mitad, son utilizados como palas. Esta turbina será nombrada como rotor hidráulico, el cual presenta algunas similitudes con el rotor Savonius. A partir de las condiciones que presenta este proyecto, se seleccionarán las parte componentes del sistema de generación de energía eléctrica, como a su vez, se verán las variables que actúan en los cálculos requeridos y así obtener una metodología que pudiese ser útil para proyectos futuros. Además, se dará una breve revisión a un extracto de un estudio confeccionado por la Comisión Nacional de Energía, CNE, sobre la energía disponible en Chile, con lo cual se puede apreciar el estado actual del país en el plano energético