1,720,967 research outputs found
Quantum jump as an objective process of nature
No full textWe study the time evolution of a linear superposition of two spatially separated wave packets, and we focus on the entanglement of the two distinct branches of the state vector with the environment. We focus in particular on the dynamics of a dissipative oscillator under the influence of objective processes of wave-function collapse, the continuous spontaneous localizations (CSL) recently proposed by Ghirardi et al. [G. C. Ghirardi, P. Pearle, and A. Rimini, Phys. Rev. A 42, 78 (1990)]. We prove that the entanglement of the system of interest with the environment induces an accumulation of spontaneous wave-function collapses denoted by us as the environment-enhanced CSL process. This process of CSL accumulation is triggered by the same mechanism of interaction between the quantum system and the environment as that responsible for relaxation and dissipation. In agreement with the predictions of a preceding paper of our group [D. Vitali, L. Tessieri, and P. Grigolini, Phys. Rev. A 50, 967 (1994)], the CSL processes are shown to produce negligible effects at the statistical level. However, if we assume the attitude stimulated by the recent literature on optical quantum jumps, which is forcing us to adopt individual-system pictures, we show that the single runs are characterized by processes of wave-function collapses occurring at times compatible in principle with the experimental observation
Wave-function collapse and quantum fluctuation-dissipation process
No full textWe study the effect that the state-vector reduction of Ghirardi, Rimini, and Weber (GRW) [Phys. Rev. D 34, 470 (1986)] has on the quantum fluctuation-dissipation process. A conventional fluctuation-dissipation process stems from the interaction between a system of interest and a macroscopic number of microscopic variables, thereby suggesting the possible occurrence of an enhancement of the GRW wave-function collapse. We carry out an exact treatment of the joint action of conventional quantum dissipation and GRW wave-function collapse in the special case where the system of interest is a harmonic oscillator. We prove that the GRW dynamics does not lead to any significant departure from the predictions of ordinary quantum mechanics, if the region of astronomically large times is disregarded, where the energy of the system diverges as an effect of a slow but steady increase caused by the GRW collapses
Spontaneous localizations, environment-induced decoherence and individual-system observations
No full textWe show that the modified version of quantum mechanics proposed by Ghirardi et al. [Phys. Rev. A 40 (1990) 78] is virtually equivalent to ordinary quantum mechanics, if a statistical perspective is adopted. However, this does not conflict with the possibility of an experimental assessment via individual-system observations
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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