Adaptive colour change and background choice behaviour in peppered moth caterpillars is mediated by extraocular photoreception

Light sensing by tissues distinct from the eye occurs in diverse animal groups, enabling circadian control and phototactic behaviour. Extraocular photoreceptors may also facilitate rapid colour change in cephalopods and lizards, but little is known about the sensory system that mediates slow colour change in arthropods. We previously reported that slow colour change in twig-mimicking caterpillars of the peppered moth (Biston betularia) is a response to achromatic and chromatic visual cues. Here we show that the perception of these cues, and the resulting phenotypic responses, does not require ocular vision. Caterpillars with completely obscured ocelli remained capable of enhancing their crypsis by changing colour and choosing to rest on colour-matching twigs. A suite of visual genes, expressed across the larval integument, likely plays a key role in the mechanism. To our knowledge, this is the first evidence that extraocular colour sensing can mediate pigment-based colour change and behaviour in an arthropod

Vooral kinderen uit bijstandsgezinnen geen kansrijke start:Ouderlijke hulpbronnen in de eerste duizend dagen tot en met de basisschoolperiode

De aanwezigheid van hulpbronnen in gezinnen is van belang voor een goede start van een kind. In dit artikel is gekeken naar onderwijsniveau, arbeidsparticipatie, welvaart, gezinsstabiliteit en mentale gezondheid van ouders in de eerste duizend dagen. Gekeken is naar de periode van conceptie tot de tweede verjaardag van in 2006 geboren kinderen en beslaat de periode van 2005 tot en met 2007. Vooral het ontbreken van meerdere hulpbronnen tegelijkertijd kan een risico betekenen voor de ontwikkeling van kinderen. Bij kinderen die opgroeien in een gezin met een bijstandsuitkering is bij 9 procent sprake van een opeenstapeling van vier risicofactoren. Bij kinderen in een gezin zonder bijstand is dat bij 0,2 procent het geval

Surface sticking and lateral diffusion of lipids in supported bilayers

The diffusion of fluorescently labeled lipids in supported bilayers is studied using two different methods: Z-scan fluorescence correlation spectroscopy (z-scan FCS) and two-focus fluorescence correlation spectroscopy (2f-FCS). It is found that the data can be fitted consistently only when taking into account partial sticking of the labeled lipids to the supporting glass surface. A kinetic reaction-diffusion model is developed and applied to the data. We find a very slow sticking rate which, however, when neglected, leads to strongly varying estimates of the free diffusion coefficient. The study reveals a strong sensitivity of FCS on even slight binding/unbinding kinetics of the labeled molecules, which has significance for related diffusion measurements in cellular lipid membranes

Sharpness of the phase transition and exponential decay of the subcritical cluster size for percolation on quasi-transitive graphs

We study homogeneous, independent percolation on general quasi-transitive graphs. We prove that in the disorder regime where all clusters are finite almost surely, in fact the expectation of the cluster size is finite. This extends a well-known theorem by Menshikov and Aizenman & Barsky to all quasi-transitive graphs. Moreover we deduce that in this disorder regime the cluster size distribution decays exponentially, extending a result of Aizenman & Newman. Our results apply to both edge and site percolation, as well as long range (edge) percolation. The proof is based on a modification of the Aizenman & Barsky method.Comment: Latex 2e; 25 pages (a4wide); small editorial corrections; one reference adde

The child's right to protection against economic exploitation in the digital world

Abstract Children face significant consumer risks when surfing online, related to, inter alia, embedded advertisements and privacy-invasive practices, as well as the exploitation of their incredulity and inexperience resulting in overspending or online fraudulent transactions. Behind the fun and playful activities available for children online lie complex revenue models, creating value for companies by feeding children's data into algorithms and self-learning models to profile them and offer personalised advertising or by nudging children to buy or try to win in-app items to advance in the games they play. In this article we argue that specific measures against these forms of economic exploitation of children in the digital world are urgently needed. We focus on three types of exploitative practices that may have a significant impact on the well-being and rights of children - profiling and automated decision-making, commercialisation of play, and digital child labour. For each type, we explain what the practice entails, situate the practice within the existing legislative and children's rights framework and identify concerns in relation to those rights. Keyword

Spectrum and diffusion for a class of tight-binding models on hypercubes

We propose a class of exactly solvable anisotropic tight-binding models on an infinite-dimensional hypercube. The energy spectrum is analytically computed and is shown to be fractal and/or absolutely continuous according to the value hopping parameters. In both cases, the spectral and diffusion exponents are derived. The main result is that, even if the spectrum is absolutely continuous, the diffusion exponent for the wave packet may be anything between 0 and 1 depending upon the class of models.Comment: 5 pages Late

Quantum Return Probability for Substitution Potentials

We propose an effective exponent ruling the algebraic decay of the average quantum return probability for discrete Schrodinger operators. We compute it for some non-periodic substitution potentials with different degrees of randomness, and do not find a complete qualitative agreement with the spectral type of the substitution sequences themselves, i.e., more random the sequence smaller such exponent.Comment: Latex, 13 pages, 6 figures; to be published in Journal of Physics