305,291 research outputs found
Le Metalloporfirine: un efficace modello di enzimi naturali. Studio meccanicistico della reazione catalitica di amminazione di gruppi benzilici
No full textInteraction between “dissipative solitons” stabilized by aggregation in excitable kinetics
No full textWe consider that a population of individuals governed by the Nagumo model is characterized by predisposition towards aggregation. “Dissipative solitons” interacting are solutions for such system. We changed the possibility of extinction, predicted by Nagumo model, by a uniform background of low population’s density and then we observed relevant effect on interaction between “solitons”.Fil: Mangioni, Sergio Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Físicas de Mar del Plata; Argentin
Generalized Nagumo Model: Interesting Effects of Parameters's Fluctuations
No full textIn this paper, we used an analytical method to calculate the effects that produce the parameter’s fluctuations characterizing a generalization of Nagumo model. (The extinction option is replaced by one of low density homogeneous population.) Moreover, we also check the results by means of numerical simulations of the corresponding stochastic process. We find that these fluctuations have a strong impact on the solutions producing interesting changes.Fil: Mangioni, Sergio Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Físicas de Mar del Plata; Argentin
Extinction avoidance by aggregation in excitable kinetics
No full textWe considerer that a population of individuals governed by the Nagumo model is subjected to a crisis that stimulates a predisposition towards aggregation. We assume that this trend is based on the physical mechanisms of attraction between individuals. Then we describe the post-crisis dynamics and find possible states of survival (stationary solutions). We see a dynamic rich in options with several possible survival responses.Fil: Mangioni, Sergio Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Físicas de Mar del Plata; Argentin
Systems confined by pusher multiplicative noises
No full textWe frequently employ the intuitive concept that a multiplicative noise can expel a system towards the field values for which intensity is negligible. This process applies even when such noise effects are opposed to the deterministic forces. In addition, it has been stated that a system may be confined by such noise within a field values region, distant from the stationary homogeneous solutions. In order to promote or explain noise-induced ordering phase transitions, the gradient of the multiplicative factor of noise is employed as if it were a force. However, there has not been a thorough study of this concept in the literature to date. In this paper, we conduct such a study.Fil: Mangioni, Sergio Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Físicas de Mar del Plata; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
A mechanism for pattern formation in dynamic populations by the effect of gregarious instinct
No full textWe introduced the gregarious instinct by means of a novel strategy that considers the average effect of the attractive forces between individuals within a given population. We watched how pattern formation can be explained by the effect of aggregation depending on conditions on food and / or mortality. We propose a model that describes the corresponding dynamic and by a linear stability analysis of homogeneous solutions and can identify and interpret the region of parameters where these patterns are stable. Then we test numerically these preliminary results and find stable patterns as solutions. Finally, we developed a simplified model allowing us to understand in greater detail the processes involved.Fil: Mangioni, Sergio Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Físicas de Mar del Plata. Grupo de Investigación del Departamento de Química de la Unmdp | Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Físicas de Mar del Plata. Grupo de Investigación del Departamento de Química de la Unmdp; Argentin
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
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