Description: In this article, the authors consider two different approaches, to which the authors refer to as renewal and modulation, to generate time series with a nonexponential distribution of waiting times. The authors show that different time series with the same waiting time distribution are not necessarily statistically equivalent, and might generate different physical properties. Renewal generates aging and anomalous scaling, while modulation yields no significant aging and either ordinary or anomalous diffusion, according to the dynamic prescription adopted. The authors show, in fact, that the physical realization of modulation generates two classes of events. The events of the first class are determined by the persistent use of the same exponential time scale for an extended lapse of time, and consequently are numerous; the events of the second class are identified with the abrupt changes from one to another exponential prescription, and consequently are rare. The events of the second class, although rare, determine the scaling of the diffusion process, and for this reason the authors term them as crucial events. According to the prescription adopted to produce modulation, the distribution density of the time distances between two consecutive crucial events might have, or not, a diverging second moment. In the ...

Description: In this article, the authors study the electroencephalogram (EEG) of 30 closed-eye subjects with a technique of analysis recently proposed to detect punctual events signaling rapid transitions between different metastable states. After single-EEG-channel event detection, the authors study global properties of events simultaneously occurring among two or more electrodes termed coincidences. The authors convert the coincidences into a diffusion process with three distinct rules that can yield the same μ only in the case where the coincidences are driven by a renewal process. The authors establish that the time interval between two consecutive renewal events driving the coincidences has a waiting-time distribution with inverse power-law index μ≈2 corresponding to ideal 1/f noise. The authors argue that this discovery, shared by all subjects of our study, supports the conviction that 1/f noise is an optimal communication channel for complex networks as in art or language and may therefore be the channel through which the brain influences complex processes and is influenced by them.

Description: This article discusses the rapid analysis of legume root nodule development using confocal microscopy. A rapid method for detailed analysis of nodule formation has been developed. Inoculated root tissues were stained with SYTO 13, a cell-permeant fluorescent nucleic acid-binding dye, and visualized using confocal laser scanning microscopy (CLSM). Structures with high concentrations of DNA and RNA, such as plant cell nuclei and bacteria, labeled strongly. The autofluorescent properties of cell walls made it possible to use CLSM to visualize both plant and rhizobial structures and generate a three-dimensional reconstruction of the root and invading bacteria. This method allowed clear observation of stages and structures important in nodule formation, such as rhizobial attachment to root hairs, hair deformation, infection thread ramification, nodule primordium development and nodule cell invasion. Bacteroid structures were easily were easily assessed without the need for fixation that might alter cellular integrity. Plant nodulation mutants with phenotypic differences in thread growth, cellular invasion and plant defense response were also documented. Multiple samples can be assessed using detailed microscopy without the need for extensive preparative work, labor-intensive analysis, or the generation of genetically modified samples.

Description: This article discusses sun-climate complexity linking. It is known that Earth's short-term temperature anomalies share the same complexity index μ as solar flares. The authors show that this property is not accidental and is a consequence of the phenomenon of information transfer based on the crucial role of non-Poisson renewal events in complex networks.

Description: This is a Publisher's Note for the article 'Beyond the Death of Linear Response: 1/f Optimal Information Transport' [Phys. Rev. Lett. 105, 040601 (2010)].