Can apps support creativity in middle childhood?

This experimental study investigated whether and how creative apps may support creativity in middle childhood (n = 94 children, 8–10 years old). Guided by the moderate discrepancy hypothesis, flow theory, and the differential susceptibility to media effects model, developmentally-appropriate creative apps were predicted to increase engagement and subsequent creativity to a greater extent than developmentally-inappropriate creative apps. Furthermore, gender and fantastical thinking were predicted to moderate effects. Results provided partial support for study hypotheses. Children were more engaged when playing developmentally-appropriate apps, however, this engagement did not translate into creativity gains. Given that the data failed to support study hypotheses, post hoc analyses were conducted to explore the findings in greater detail. These additional analyses indicated that developmentally-appropriate apps not only lead to greater engagement, but were subsequently more appealing as well. These post hoc findings are discussed within the context of the study design, particularly noting that greater duration of play may be necessary to move the needle on creative skills. Empirical and practical implications are discussed

Throughput of ADSL modems

This paper considers the throughput of ADSL (Asymmetric Digital Subscriber Line) modems, used for high-speed data transmission over relatively unreliable connections, e.g. copper telephone wires. The modem technique uses an error correcting code and interleaving. The settings include a grouping factor $S$ which affects the amount of data per code word, the number $R$ of redundant bytes per code word and the interleave depth $D$. The influence of these parameters on both the effective data transmission rate and the resulting error rate in the received signal are determined for two error situations: random errors and bursts of errors. An approximate analysis for the random error case of the throughput of a TCP (Transport Control Protocol) connection using an ADSL modem shows that maximum throughput is obtained for the highest values of $S$ and $R$

Covering algorithms, continuum percolation and the geometry of wireless networks

Continuum percolation models in which each point of a two-dimensional Poisson point process is the centre of a disc of given (or random) radius r, have been extensively studied. In this paper, we consider the generalization in which a deterministic algorithm (given the points of the point process) places the discs on the plane, in such a way that each disc covers at least one point of the point process and that each point is covered by at least one disc. This gives a model for wireless communication networks, which was the original motivation to study this class of problems. We look at the percolation properties of this generalized model, showing that an unbounded connected component of discs does not exist, almost surely, for small values of the density lambda of the Poisson point process, for any covering algorithm. In general, it turns out not to be true that unbounded connected components arise when lambda is taken sufficiently high. However, we identify some large families of covering algorithms, for which such an unbounded component does arise for large values of lambda. We show how a simple scaling operation can change the percolation properties of the model, leading to the almost sure existence of an unbounded connected component for large values of lambda, for any covering algorithm. Finally, we show that a large class of covering algorithms, which arise in many practical applications, can get arbitrarily close to achieving a minimal density of covering discs. We also construct an algorithm that achieves this minimal density

Catch them ... if you can

An important part of forensic science is dedicated to the evaluation of physical traces left at the crime scene like fingerprints, bullets, toolmarks etc. These traces are compared with traces from a suspect. The evaluation of physical traces can be interpreted as the comparison of two noisy signals. We introduce an evaluation of the matching of two noisy signals at diverse scales and localisations in space. In a multi-resolution way a "probability" of matching is computed. Furthermore, a description is given to evaluate the complexity of a shoemark. A likelihood ratio approach is used for comparing two shoemark traces

Single nucleotide polymorphism discovery from expressed sequence tags in the waterflea Daphnia magna

<p>Abstract</p> <p>Background</p> <p><it>Daphnia </it>(Crustacea: Cladocera) plays a central role in standing aquatic ecosystems, has a well known ecology and is widely used in population studies and environmental risk assessments. <it>Daphnia magna </it>is, especially in Europe, intensively used to study stress responses of natural populations to pollutants, climate change, and antagonistic interactions with predators and parasites, which have all been demonstrated to induce micro-evolutionary and adaptive responses. Although its ecology and evolutionary biology is intensively studied, little is known on the functional genomics underpinning of phenotypic responses to environmental stressors. The aim of the present study was to find genes expressed in presence of environmental stressors, and target such genes for single nucleotide polymorphic (SNP) marker development.</p> <p>Results</p> <p>We developed three expressed sequence tag (EST) libraries using clonal lineages of <it>D. magna </it>exposed to ecological stressors, namely fish predation, parasite infection and pesticide exposure. We used these newly developed ESTs and other <it>Daphnia </it>ESTs retrieved from NCBI GeneBank to mine for SNP markers targeting synonymous as well as non synonymous genetic variation. We validate the developed SNPs in six natural populations of <it>D. magna </it>distributed at regional scale.</p> <p>Conclusions</p> <p>A large proportion (47%) of the produced ESTs are <it>Daphnia </it>lineage specific genes, which are potentially involved in responses to environmental stress rather than to general cellular functions and metabolic activities, or reflect the arthropod's aquatic lifestyle. The characterization of genes expressed under stress and the validation of their SNPs for population genetic study is important for identifying ecologically responsive genes in <it>D. magna</it>.</p

A Conformal Field Theory for Eternal Inflation

We study a statistical model defined by a conformally invariant distribution of overlapping spheres in arbitrary dimension d. The model arises as the asymptotic distribution of cosmic bubbles in d+1 dimensional de Sitter space, and also as the asymptotic distribution of bubble collisions with the domain wall of a fiducial "observation bubble" in d+2 dimensional de Sitter space. In this note we calculate the 2-,3-, and 4-point correlation functions of exponentials of the "bubble number operator" analytically in d=2. We find that these correlators, when carefully defined, are free of infrared divergences, covariant under the global conformal group, charge conserving, and transform with positive conformal dimensions that are related in a novel way to the charge. Although by themselves these operators probably do not define a full-fledged conformal field theory, one can use the partition function on a sphere to compute an approximate central charge in the 2D case. The theory in any dimension has a noninteracting limit when the nucleation rate of the bubbles in the bulk is very large. The theory in two dimensions is related to some models of continuum percolation, but it is conformal for all values of the tunneling rate.Comment: 30 pages, 8 figure

Local adaptation of a bacterium is as important as its presence in structuring a natural microbial community

This is the final version of the article. Available from Springer Nature via the DOI in this record.Local adaptation of a species can affect community composition, yet the importance of local adaptation compared with species presence per se is unknown. Here we determine how a compost bacterial community exposed to elevated temperature changes over 2 months as a result of the presence of a focal bacterium, Pseudomonas fluorescens SBW25, that had been pre-adapted or not to the compost for 48 days. The effect of local adaptation on community composition is as great as the effect of species presence per se, with these results robust to the presence of an additional strong selection pressure: an SBW25-specific virus. These findings suggest that evolution occurring over ecological time scales can be a key driver of the structure of natural microbial communities, particularly in situations where some species have an evolutionary head start following large perturbations, such as exposure to antibiotics or crop planting and harvesting.The work was funded by BBSRC, AXA Research fund and NERC. P.G. was supported by a Marie Curie Intra-European Fellowship within the European Commission 7th Framework Program (PIEF-GA-2010-272945), and acknowledges the Spanish MINECO support (AGL2014-59556-R). A.B. was supported by the Royal Society (UK). L.D.M. acknowledges the KU Leuven Research Fund support PF/2010/07