Search results for "complex"
showing 10 items of 5889 documents
Feigenbaum graphs: a complex network perspective of chaos
2011
The recently formulated theory of horizontal visibility graphs transforms time series into graphs and allows the possibility of studying dynamical systems through the characterization of their associated networks. This method leads to a natural graph-theoretical description of nonlinear systems with qualities in the spirit of symbolic dynamics. We support our claim via the case study of the period-doubling and band-splitting attractor cascades that characterize unimodal maps. We provide a universal analytical description of this classic scenario in terms of the horizontal visibility graphs associated with the dynamics within the attractors, that we call Feigenbaum graphs, independent of map…
The Role of Contextual Factors in the Influence of ICT on Street-Level Discretion
2017
Public service workers in the frontline have traditionally enjoyed a wide freedom to make decisions during policy implementation. Research shows that technology has both constraining and enabling effects on public service workers affecting their ability to exercise discretion. What remains unclear is under which circumstances discretion is influenced by technology. Using a case study approach and drawing on neo-institutional theory, this paper studies a court to identify contextual factors affecting the phenomenon. Findings show that technology has no unilateral effect on street-level discretion, and is found moderated by contextual factors such as the degree of social complexity in a case,…
E-heutagogy for lifelong e-learning
2012
Abstract The paper aims to introduce a new concept: e-heutagogy. This aim is approached through two sub-objectives:a) Giving the rationale for the new concept of e-heutagogy.b) Outlining the features of e-heutagogy necessary for lifelong e-learning.Why do we need a new concept? Learning is a complex concept and it is a part of our entire life. Today we can speak about new generations of learners at all levels, from kindergarten to university, not only due to technology but also due to rapid changes in open, heterogeneous, dynamic and uncertain environments.Taking into account that heutagogy is appropriate to the needs of learners but learners are most of their life without their teachers an…
Ligand-Based Charge-Transfer Luminescence in Ionic Cyclometalated Iridium(III) Complexes Bearing a Pyrene-Functionalized Bipyridine Ligand: A Joint T…
2012
Two new heteroleptic iridium(III) complexes [Ir(ppy)(2)(pyr(2)bpy)][PF(6)] ([1a][PF(6)]) and [Ir(dfppy)(2)(pyr(2)bpy)][PF(6)] ([2a][PF(6)]), where Hppy = 2-phenylpyridine, Hdfppy = 2-(3,5-difluorophenyl)pyridine, and pyr(2)bpy = 5,5'-bis(pyren-1-yl)-2,2'-bipyridine, have been synthesized and fully characterized. The single-crystal structures of pyr(2)bpy and the complexes 4{[1a][PF(6)]}·2CH(2)Cl(2)·9H(2)O and [2a][PF(6)]·0.25CH(2)Cl(2)·H(2)O have been determined. The effect of the pyrene substituents on the electronic properties is investigated through a comprehensive photophysical and theoretical study on the two complexes in comparison to reference complexes without substituents on the an…
Photophysical Properties of Charged Cyclometalated Ir(III) Complexes: A Joint Theoretical and Experimental Study
2011
The photophysical properties of a series of charged biscyclometalated [Ir(ppy)(2)(N boolean AND N)](1+) complexes, where ppyH is 2-phenylpyridine and N boolean AND N is 2,2'-bipyridine (bpy), 6-phenyl-2,2'-bipyridine (pbpy), and 6,6'-dipheny1-2,2'-bipyridine (dpbpy) for complexes 1, 2, and 3, respectively, have been investigated in detail. The photoluminescence performance in solution decreases from 1 to 3 upon attachment of phenyl groups to the ancillary ligand. The absorption spectra recorded over time suggest that complex 3 is less stable compared to complexes 1 and 2 likely due to a nucleophilic-assisted ancillary ligand-exchange reaction. To clarify this behavior, the temperature depen…
Employees' work patterns-office type fit and the dynamic relationship between flow and performance
2021
Organizations must improve their employees’ performance in order to compete effectively. Evidence shows that flow experiences enhance performance. However, a dynamic approach to this phenomenon is needed. Furthermore, different work patterns (based on task profiles) can have specific environmental requirements (office types). This research aims to analyze the dynamic relationship between office workers’ flow and in‐role and extra‐role performance, considering work pattern–office type fit as a predictor of the initial level of each of these three variables. A total of 83 workers participated in this diary study. Results of the latent growth model showed a positive association between: (1) th…
Growth of nucleation mode particles in the summertime Arctic: a case study
2016
Abstract. The summertime Arctic lower troposphere is a relatively pristine background aerosol environment dominated by nucleation and Aitken mode particles. Understanding the mechanisms that control the formation and growth of aerosol is crucial for our ability to predict cloud properties and therefore radiative balance and climate. We present an analysis of an aerosol growth event observed in the Canadian Arctic Archipelago during summer as part of the NETCARE project. Under stable and clean atmospheric conditions, with low inversion heights, carbon monoxide less than 80 ppbv, and black carbon less than 5 ng m−3, we observe growth of small particles, < 20 nm in diameter, into sizes ab…
Ecological Complex Systems
2008
Main aim of this topical issue is to report recent advances in noisy nonequilibrium processes useful to describe the dynamics of ecological systems and to address the mechanisms of spatio-temporal pattern formation in ecology both from the experimental and theoretical points of view. This is in order to understand the dynamical behaviour of ecological complex systems through the interplay between nonlinearity, noise, random and periodic environmental interactions. Discovering the microscopic rules and the local interactions which lead to the emergence of specific global patterns or global dynamical behaviour and the noises role in the nonlinear dynamics is an important, key aspect to unders…
Resource competition between sympatric sibling rotifer species
2001
Mechanisms underlying competitive interactions are important in understanding the structure of planktonic communities, particularly the coexistence of similar species. Here we present experimental results of exploitative competition among three sympatric sibling species of the Brachionus plicatilis complex for two differently-sized species of food microalgae. These three rotifer species are to be found in seasonal succession in brackish ponds on the Spanish Mediterranean coast; they can, however, co-occur for long periods. The functional and numerical responses of the three Brachionus species to both food microalgae, although similar, differed. Neither rotifer population growth nor grazing …
Dinner with the roommates: trophic niche differentiation and competition in a mutualistic ant‐ant association
2020
1. The potential for competition is highest among species in close association. Despite net benefits for both parties, mutualisms can involve costs, including food competition. This might be true for the two neotropical ants Camponotus femoratus and Crematogaster levior, which share the same nest in a presumably mutualistic association (parabiosis). 2. While each nest involves one Crematogaster and one Camponotus partner, both taxa were recently found to comprise two cryptic species that show no partner preferences and seem ecologically similar. Since these cryptic species often occur in close sympatry, they might need to partition their niches to avoid competitive exclusion. 3. Here, we in…