Critical dynamics of ballistic and Brownian particles in a heterogeneous environment

The dynamic properties of a classical tracer particle in a random, disordered medium are investigated close to the localization transition. For Lorentz models obeying Newtonian and diffusive motion at the microscale, we have performed large-scale computer simulations, demonstrating that universality holds at long times in the immediate vicinity of the transition. The scaling function describing the crossover from anomalous transport to diffusive motion is found to vary extremely slowly and spans at least 5 decades in time. To extract the scaling function, one has to allow for the leading universal corrections to scaling. Our findings suggest that apparent power laws with varying exponents generically occur and dominate experimentally accessible time windows as soon as the heterogeneities cover a decade in length scale. We extract the divergent length scales, quantify the spatial heterogeneities in terms of the non-Gaussian parameter, and corroborate our results by a thorough finite-size analysis.Comment: 14 page

Multi-Resolution Analysis and Fractional Quantum Hall Effect: an Equivalence Result

In this paper we prove that any multi-resolution analysis of \Lc^2(\R) produces, for some values of the filling factor, a single-electron wave function of the lowest Landau level (LLL) which, together with its (magnetic) translated, gives rise to an orthonormal set in the LLL. We also give the inverse construction. Moreover, we extend this procedure to the higher Landau levels and we discuss the analogies and the differences between this procedure and the one previously proposed by J.-P. Antoine and the author.Comment: Submitted to Journal Mathematical Physisc

Phonon-like and single particle dynamics in liquid lithium

The dynamic structure factor, S(Q,E), of liquid lithium (T=475 K) has been determined by inelastic x-ray scattering (IXS) in the momentum transfer region (Q = 1.4-110 nm-1). These data allow to observe how, in a simple liquid, a phonon-like collective mode evolves towards the single particle dynamics. As a function of Q, one finds: i) at low Q's, a sound mode with a positive dispersion of the sound velocity, ii) at intermediate Q's, excitations whose energy oscillates similarly to phonons in the crystal Brillouin zones, and iii) at high Q's, the S(Q,E) approaches a Gaussian shape, indicating that the single particle dynamics has been reached.Comment: 3 pages and 5 figure

Microbial community of predatory bugs of the genus Macrolophus (Hemiptera: Miridae)

<p>Abstract</p> <p>Background</p> <p>The predatory mirids of the genus <it>Macrolophus</it> are key natural enemies of various economically important agricultural pests. Both <it>M. caliginosus</it> and <it>M. pygmaeus</it> are commercially available for the augmentative biological control of arthropod pests in European greenhouses. The latter species is known to be infected with <it>Wolbachia</it> -inducing cytoplasmic incompatibility in its host- but the presence of other endosymbionts has not been demonstrated. In the present study, the microbial diversity was examined in various populations of <it>M. caliginosus</it> and <it>M. pygmaeus</it> by 16S rRNA sequencing and denaturing gradient gel electrophoresis.</p> <p>Results</p> <p>Besides <it>Wolbachia</it>, a co-infection of 2 <it>Rickettsia</it> species was detected in all <it>M. pygmaeus</it> populations. Based on a concatenated alignment of the <it>16S rRNA</it> gene, the <it>gltA</it> gene and the <it>coxA</it> gene, the first is phylogenetically related to <it>Rickettsia bellii</it>, whereas the other is closely related to <it>Rickettsia limoniae</it>. All <it>M. caliginosus</it> populations were infected with the same <it>Wolbachia</it> and <it>limoniae</it>-like <it>Rickettsia</it> strain as <it>M. pygmaeus</it>, but did not harbour the <it>bellii</it>-like <it>Rickettsia</it> strain. Interestingly, individuals with a single infection were not found. A PCR assay on the ovaries of <it>M. pygmaeus</it> and <it>M. caliginosus</it> indicated that all endosymbionts are vertically transmitted. The presence of <it>Wolbachia</it> and <it>Rickettsia</it> in oocytes was confirmed by a fluorescence <it>in situ</it> hybridisation. A bio-assay comparing an infected and an uninfected <it>M. pygmaeus</it> population suggested that the endosymbionts had minor effects on nymphal development of their insect host and did not influence its fecundity.</p> <p>Conclusion</p> <p>Two species of the palaearctic mirid genus <it>Macrolophus</it> are infected with multiple endosymbionts, including <it>Wolbachia</it> and <it>Rickettsia</it>. Independent of the origin, all tested populations of both <it>M. pygmaeus</it> and <it>M. caliginosus</it> were infected with three and two endosymbionts, respectively. There was no indication that infection with endosymbiotic bacteria had a fitness cost in terms of development and fecundity of the predators.</p

Childhood Characteristics of Adolescent Inpatients with Early-Onset and Adolescent-Onset Disruptive Behavior

Childhood characteristics are associated with life-course-persistent antisocial behavior in epidemiological studies in general population samples. The present study examines this association in an inpatient sample. The purpose is to identify easily measurable childhood characteristics that may guide choice of treatment for adolescent psychiatric inpatients with severe disruptive behavior. Patients (N = 203) were divided into two groups with either early-onset (EO) or adolescent-onset (AO) disruptive behavior, based on ages at which professional care was used for disruptive behavior, referral to special education, and criminal offences. Both groups differed on several childhood characteristics. No gender differences in these characteristics were found. Logistic regression analysis indicated that individuals with grade retention in primary school, childhood impulsive behavior, and a history of physical abuse, had the highest probability of being member of the EO group. These characteristics are reasonably easy to identify, likely apply to other clinical samples as well, and may help clinicians to target their treatment

Scalar Field Cosmology II: Superfluidity, Quantum Turbulence, and Inflation

We generalize the big-bang model in a previous paper by extending the real vacuum scalar field to a complex vacuum scalar field, within the FLRW framework. The phase dynamics of the scalar field, which makes the universe a superfluid, is described in terms of a density of quantized vortex lines, and a tangle of vortex lines gives rise to quantum turbulence. We propose that all the matter in the universe was created in the turbulence, through reconnection of vortex lines, a process necessary for the maintenance of the vortex tangle. The vortex tangle grows and decays, and its lifetime is the era of inflation. These ideas are implemented in a set of closed cosmological equations that describe the cosmic expansion driven by the scalar field on the one hand, and the vortex-matter dynamics on the other. We show how these two aspects decouple from each other, due to a vast difference in energy scales. The model is not valid beyond the inflation era, but the universe remains a superfluid afterwards. This gives rise to observable effects in the present universe, including dark matter, galactic voids, non-thermal filaments, and cosmic jets.Comment: 29 pages, 7 figures, published versio

Random paths and current fluctuations in nonequilibrium statistical mechanics

An overview is given of recent advances in nonequilibrium statistical mechanics about the statistics of random paths and current fluctuations. Although statistics is carried out in space for equilibrium statistical mechanics, statistics is considered in time or spacetime for nonequilibrium systems. In this approach, relationships have been established between nonequilibrium properties such as the transport coefficients, the thermodynamic entropy production, or the affinities, and quantities characterizing the microscopic Hamiltonian dynamics and the chaos or fluctuations it may generate. This overview presents results for classical systems in the escape-rate formalism, stochastic processes, and open quantum systems

Considering Intra-individual Genetic Heterogeneity to Understand Biodiversity

In this chapter, I am concerned with the concept of Intra-individual Genetic Hetereogeneity (IGH) and its potential influence on biodiversity estimates. Definitions of biological individuality are often indirectly dependent on genetic sampling -and vice versa. Genetic sampling typically focuses on a particular locus or set of loci, found in the the mitochondrial, chloroplast or nuclear genome. If ecological function or evolutionary individuality can be defined on the level of multiple divergent genomes, as I shall argue is the case in IGH, our current genetic sampling strategies and analytic approaches may miss out on relevant biodiversity. Now that more and more examples of IGH are available, it is becoming possible to investigate the positive and negative effects of IGH on the functioning and evolution of multicellular individuals more systematically. I consider some examples and argue that studying diversity through the lens of IGH facilitates thinking not in terms of units, but in terms of interactions between biological entities. This, in turn, enables a fresh take on the ecological and evolutionary significance of biological diversity

New learning opportunities in a networked world: developing a research agenda on innovative uses of ICTS for learning and teaching

IDRC Project Title: Developing a Research Agenda on Expanding New Digital Learning Opportunities in Developing Countries;IDRC Project Number: 107628The report describes outcomes of the activities carried out for the project “New Learning Opportunities in a Networked World: Developing a Research Agenda on Innovative uses of ICTs for Learning and Teaching”. The research consists of three main activities, namely desk research, written expert consultation and group concept mapping study involving a 2-day workshop and a follow-up with experts who could not attend the workshop. These activities are interconnected elements of the consultative approach to establishing a research agenda.International Development Research Centre (IDRC), Canad