Epidemic spreading in evolving networks

A model for epidemic spreading on rewiring networks is introduced and analyzed for the case of scale free steady state networks. It is found that contrary to what one would have naively expected, the rewiring process typically tends to suppress epidemic spreading. In particular it is found that as in static networks, rewiring networks with degree distribution exponent $\gamma >3$ exhibit a threshold in the infection rate below which epidemics die out in the steady state. However the threshold is higher in the rewiring case. For $2<\gamma \leq 3$ no such threshold exists, but for small infection rate the steady state density of infected nodes (prevalence) is smaller for rewiring networks.Comment: 7 pages, 7 figure

Spinal arthritis in invasive cane toads is linked to rate of dispersal as well as to latitude

Initial research on the spread of cane toads (Rhinella marina) through tropical Australia reported a high incidence of spinal arthritis (spondylosis) in toads at the invasion front (where toads disperse rapidly), but not in areas colonized earlier (where toads are more sedentary). The idea that spondylosis was a cost of rapid dispersal was challenged by wider spatial sampling which linked rates of spondylosis to hot (tropical) climates rather than to dispersal rates. Here, the authors of these competing interpretations collaborate to reinterpret the data. Our reanalysis supports both previous hypotheses; rates of spondylosis are higher in populations established by fast-dispersing toads, and are higher in tropical than in temperate environments; they are also higher in larger toads. The functional reason for climatic effects is unclear, but might involve effects on the soil-living bacteria involved in the induction of spondylosis; and/or may reflect higher movement (as opposed to dispersal) or more pronounced dry-season aggregation rates of toads in tropical conditions

Zero-range processes with saturated condensation: the steady state and dynamics

We study a class of zero-range processes in which the real-space condensation phenomenon does not occur and is replaced by a saturated condensation: that is, an extensive number of finite-size "condensates" in the steady state. We determine the conditions under which this occurs, and investigate the dynamics of relaxation to the steady state. We identify two stages: a rapid initial growth of condensates followed by a slow process of activated evaporation and condensation. We analyze these nonequilibrium dynamics with a combination of meanfield approximations, first-passage time calculations and a fluctuation-dissipation type approach.Comment: 21 pages, 12 figure

Stacking chairs:local sense and global nonsense

We report a confusing stimulus which demonstrates the power of local interpretation of threedimensional structure to disrupt a coherent global perception

Work restructuring and changing craft identity: the Tale of the Disaffected Weavers (or what happens when the rug is pulled from under your feet)

This article explores the changes in worker identity that can occur during manufacturing restructuring – specifically those linked to the declining status of craft work – through an in-depth case study of Weaveco, a UK carpet manufacturer. An analysis of changes in the labour process is followed by employee reactions centred on the demise of the traditional craft identity of male carpet weavers. The voices of the weavers dramatize the tensions involved in reconstructing their masculine identity, and we consider the implications this has for understanding gendered work relations

Demonstration of a picosecond Bragg switch for hard x-rays in a synchrotron-based pump-probe experiment

We report a benchmark experiment that demonstrates shortening of hard x-ray pulses in a synchrotron-based optical pump - x-ray probe experiment. The pulse shortening device, a picosecond Bragg switch, reduces the temporal resolution of an incident x-ray pulse to 7.5 ps. We employ the Bragg switch to monitor propagating sound waves in nanometer-thin epitaxial films. With the experimental data we infer pulse duration, diffraction efficiency and switching contrast of the device. A detailed efficiency analysis shows, that the switch can deliver up to 1010 photons/sec in high-repetition rate synchrotron experiments

Perception and Processing of Faces in the Human Brain Is Tuned to Typical Feature Locations.

UNLABELLED: Faces are salient social stimuli whose features attract a stereotypical pattern of fixations. The implications of this gaze behavior for perception and brain activity are largely unknown. Here, we characterize and quantify a retinotopic bias implied by typical gaze behavior toward faces, which leads to eyes and mouth appearing most often in the upper and lower visual field, respectively. We found that the adult human visual system is tuned to these contingencies. In two recognition experiments, recognition performance for isolated face parts was better when they were presented at typical, rather than reversed, visual field locations. The recognition cost of reversed locations was equal to ∼60% of that for whole face inversion in the same sample. Similarly, an fMRI experiment showed that patterns of activity evoked by eye and mouth stimuli in the right inferior occipital gyrus could be separated with significantly higher accuracy when these features were presented at typical, rather than reversed, visual field locations. Our findings demonstrate that human face perception is determined not only by the local position of features within a face context, but by whether features appear at the typical retinotopic location given normal gaze behavior. Such location sensitivity may reflect fine-tuning of category-specific visual processing to retinal input statistics. Our findings further suggest that retinotopic heterogeneity might play a role for face inversion effects and for the understanding of conditions affecting gaze behavior toward faces, such as autism spectrum disorders and congenital prosopagnosia. SIGNIFICANCE STATEMENT: Faces attract our attention and trigger stereotypical patterns of visual fixations, concentrating on inner features, like eyes and mouth. Here we show that the visual system represents face features better when they are shown at retinal positions where they typically fall during natural vision. When facial features were shown at typical (rather than reversed) visual field locations, they were discriminated better by humans and could be decoded with higher accuracy from brain activity patterns in the right occipital face area. This suggests that brain representations of face features do not cover the visual field uniformly. It may help us understand the well-known face-inversion effect and conditions affecting gaze behavior toward faces, such as prosopagnosia and autism spectrum disorders