1,721,821 research outputs found
Reconciling Statistical Models with Practical Experience of Reverberation Chambers
Full text linkPresented are novel theoretical probability density functions (PDF) for the magnitude and phase of electromagnetic fields inside reverberation chambers (RC) operating in a dasiagood-but-imperfect regime. The derivation is based on considering two Gaussian random variables with mean values, variances and correlation between them that depart from the ideal assumptions. A multivariate approach using a complete joint Gaussian distribution of these variables is defined. Marginal distributions obtained by integration of this two-dimensional joint PDF are compared with theoretical PDFs for ideal situations, and significantly lower rejection rates are experienced for field data measured in real RCs. Additionally, these novel marginal PDFs are highly general since they are able to describe both ideal and non-ideal stirred fields
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
Linking a One-Dimensional Reverberation Chamber Model with Real Reverberation Chambers
Full text linkA stochastic model of growing and dividing protocells
No full textIn the last two chapters we have shown several interesting results, which will now be brought together in a quite complete (albeit abstract) protocell model. In Chap. 3 we have studied how the presence of genetic memory molecules (GMMs) can affect the growth and fission rate of their lipid container, leading under quite broad assumptions to the important phenomenon of emergent synchronization, i.e. to a condition where protocell fission and duplication of its genetic material take place at the same pace. In that chapter, chemical kinetics has been described with deterministic differential equations (it has also been mentioned that synchronization is somewhat robust even if small fluctuations are considered)
Generic properties of dynamical models of protocells
No full textModels are of great importance for protocell research, not only for the usual reasons why models matter, but also because real protocells are not yet available in the lab. There are indeed some cases where one or a few duplications have been achieved (Hanczyc and Szostak 2004; Luisi et al. 2004; Luisi 2006; Stano et al. 2006; Schrum et al. 2010; Stano and Luisi 2010a) but so far, to the best of our knowledge, a sustained growth of a population of protocells has never been observed
Models of self-replication
No full textA protocell could be schematically described as a self-organized, spatially confined collection of chemical species and chemical reactions, able to support the three main properties of living systems: metabolism, reproduction and inheritance. In living systems, while some chemicals are exclusively dedicated to a single activity, like DNA that is devoted to template-based replication, it often happens that the same chemical substance can participate (as substrate, product or catalyst) to many different reactions, which in turn can contribute to the different properties mentioned above; moreover the same reaction may be involved in more than one property. The components are not freely fluctuating within the environment, but are spatially confined by membranes in very small containers (cells)
Dynamical models of protocells and synchronization
No full textLet us now consider the contributions that a complex systems approach can provide to the research on protocells
Angelo De Vincenti, un neuropatologo benefattore
No full textbiografia di un neurologo, tra i fondatori della disciplina a fino Ottocent
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