1,720,955 research outputs found
Operatorial formulation of crimo-taxis phenomena in a street
No full textIn this paper, the ladder operators and a quantum-like approach are used to construct an operatorial version of a model dubbed crimo-taxis. In a classical framework, the crimo-taxis model is represented by reaction-diffusion partial differential equations that describe a population divided into three interacting subgroups (ordinary citizens, drug users/dealers, and law enforcement personnel) living in a one-dimensional spatial region representing a street. In this new framework, the agents of the subgroups are modeled using annihilation, creation, and number fermionic operators, and their time evolution is assumed to be ruled by a Hermitian time-independent Hamiltonian operator suitable to capture the interactions among the subgroups. Furthermore, a recent extension of the standard Heisenberg view, namely ( H , ρ ) -induced dynamics, is also taken into account. Two scenarios, characterized by different initial spatial distributions of the subgroups, are considered. The results of some numerical simulations in a one-dimensional setting are presented and discussed
Operatorial Formulation of a Model of Spatially Distributed Competing Populations
No full textThis paper deals with the application of the mathematical apparatus of quantum mechanics for the formulation of an operatorial model of a couple of populations spatially distributed over a one-dimensional region. The two populations interact with a competitive mechanism and are able to diffuse over the region. A nonlocal competition effect is also included. In more detail, we consider a one-dimensional region divided in N cells where the actors, represented by annihilation, creation, and a number fermionic operators, interact. The dynamics is governed by a self-adjoint and time-independent Hamiltonian operator describing the various interactions. The results of some numerical simulations are presented and discussed. The recently introduced variant of the standard Heisenberg approach, named (H,ρ)-induced dynamics, is also used in order to take into account some changes in time of the attitudes of the two populations, and obtain more realistic dynamical outcomes
From classical to operatorial models
Full text linkMathematical models for the collective dynamics of interacting and spatially distributed
populations find applications in several contexts (biology, ecology, social
sciences). Their formulation depends primarily on the (continuous or discrete) description
of the space. Reaction-diffusion equations have been widely used in bioecology
(morphogenesis, migration of biological species, tumor growth, neuro-degenerative
diseases) and in the social sciences (diffusion of opinions or decisionmaking
processes), and exhibit complex behaviors (propagation of oscillatory phenomena,
pattern formation caused by instability). A reaction–diffusion system exhibits
diffusion-driven instability, sometimes called Turing instability, if the homogeneous
steady state is stable to small perturbations in the absence of diffusion but
unstable to small spatial perturbations when diffusion is present. In this thesis, we
move from this classical approach, considering a so called crimo-taxis model (Epstein,
1997), and proposing two variants (Inferrera et al., 2022) enabling us to study
the formation of some patterns due to instability driven by self- and cross-diffusion
terms, to operatorial models built by means of some techniques typical of quantum
mechanics (see Bagarello, 2012; Bagarello, 2019). The leading idea in this approach
relies on the evidence, shown in the last fifteen years in several applications, that
the operatorial framework provides useful tools for describing the interactions occurring
within macroscopic systems. Therefore, three applications of the operatorial
formalism are discussed:
1)an operatorial version of crimo-taxis model;
2)a model where two populations spatially distributed in a one–dimensional domain
compete both locally and nonlocally and are able to migrate (Inferrera
and Oliveri, 2022);
3) a model of a finite number of agents subjected both to cooperative and competitive
interactions (Gorgone, Inferrera, and Oliveri, 2022)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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