On stochastic sea of the standard map

Consider a generic one-parameter unfolding of a homoclinic tangency of an area preserving surface diffeomorphism. We show that for many parameters (residual subset in an open set approaching the critical value) the corresponding diffeomorphism has a transitive invariant set $\Omega$ of full Hausdorff dimension. The set $\Omega$ is a topological limit of hyperbolic sets and is accumulated by elliptic islands. As an application we prove that stochastic sea of the standard map has full Hausdorff dimension for sufficiently large topologically generic parameters.Comment: 36 pages, 5 figure

A unification in the theory of linearization of second order nonlinear ordinary differential equations

In this letter, we introduce a new generalized linearizing transformation (GLT) for second order nonlinear ordinary differential equations (SNODEs). The well known invertible point (IPT) and non-point transformations (NPT) can be derived as sub-cases of the GLT. A wider class of nonlinear ODEs that cannot be linearized through NPT and IPT can be linearized by this GLT. We also illustrate how to construct GLTs and to identify the form of the linearizable equations and propose a procedure to derive the general solution from this GLT for the SNODEs. We demonstrate the theory with two examples which are of contemporary interest.Comment: 8 page

Oscillatory dynamics of a superconductor vortex lattice in high amplitude ac magnetic fields

In this work we study by ac susceptibility measurements the evolution of the solid vortex lattice mobility under oscillating forces. Previous work had already shown that in YBCO single crystals, below the melting transition, a temporarily symmetric magnetic ac field (e.g. sinusoidal, square, triangular) can heal the vortex lattice (VL) and increase its mobility, but a temporarily asymmetric one (e.g. sawtooth) of the same amplitude can tear the lattice into a more pinned disordered state. In this work we present evidence that the mobility of the VL is reduced for large vortex displacements, in agreement with predictions of recent simulations. We show that with large symmetric oscillating fields both an initially ordered or an initially disordered VL configuration evolve towards a less mobile lattice, supporting the scenario of plastic flow.Comment: 5 pages, 4 figures. To appear in Phys. Rev.

Clone size distributions in networks of genetic similarity

We build networks of genetic similarity in which the nodes are organisms sampled from biological populations. The procedure is illustrated by constructing networks from genetic data of a marine clonal plant. An important feature in the networks is the presence of clone subgraphs, i.e. sets of organisms with identical genotype forming clones. As a first step to understand the dynamics that has shaped these networks, we point up a relationship between a particular degree distribution and the clone size distribution in the populations. We construct a dynamical model for the population dynamics, focussing on the dynamics of the clones, and solve it for the required distributions. Scale free and exponentially decaying forms are obtained depending on parameter values, the first type being obtained when clonal growth is the dominant process. Average distributions are dominated by the power law behavior presented by the fastest replicating populations.Comment: 17 pages, 4 figures. One figure improved and other minor changes. To appear in Physica

R-parity as a residual gauge symmetry : probing a theory of cosmological dark matter

We present a non-supersymmetric scenario in which the R-parity symmetry $R_P = (-1)^{3(B-L)+2s}$ arises as a result of spontaneous gauge symmetry breaking, leading to a viable Dirac fermion WIMP dark matter candidate. Direct detection in nuclear recoil experiments probes dark matter masses around $2-5$ TeV for $M_{Z^{\prime}} \sim 3-4$ TeV consistent with searches at the LHC, while lepton flavor violation rates and flavor changing neutral currents in neutral meson systems lie within reach of upcoming experiments.Comment: 7 pages, 3 figure

Genome sequence of Rhizobium sullae HCNT1 isolated from Hedysarum coronarium nodules and featuring peculiar denitrification phenotypes

The genome sequence of Rhizobium sullae strain HCNT1, isolated from root nodules of the legume Hedysarum coronarium growing in wild stands in Tuscany, Italy, is described here. Unlike other R. sullae strains, this isolate features a truncated denitrification pathway lacking NO/N2O reductase activity and displaying high sensitivity to nitrite under anaerobic conditions

‘Who really speaks like that?’– Children’s implicit and explicit attitudes towards multilingual speakers of Dutch

This study investigates children’sexplicitand implicit language attitudes in a highly diverse primary education. Set in the bilingual province of Fryslân, the Netherlands, the current research was carried out in the scope of the 3M-project (‘More opportunities with multilingualism’: Duarte & Günther-van der Meij, 2018a. A holistic model for multilingualism in education. EuroAmerican Journal of Applied Linguistics and Languages, 5(2), 24–43. https://doi.org/ 10.21283/2376905X.9.153), wherein pupils’ home languages are used as a resource to promote multilingualism and thereby facilitate learning. We examined socially significant language attitudes and children’s stereotypes towards prevalent minority and migrant languages. Participants consisted of 93 pupils (aged 7–12). They completed questionnaires to assess their explicit attitudes towards majority, migrant and minority languages. Additionally, 137 pupils performed an Implicit Association Test (IAT) to measure the relative attitudes of standard Dutch versus (1) the regional minority language (Frisian) and versus (2) a salient migrant language (Moroccan Arabic). Questionnaire results show significantly lower ratings for Moroccan Arabic and ‘other languages’ compared to Dutch, English and Frisian. Implicit results revealed a larger and significant preference for Dutch over Moroccan-Dutch accents and a smaller, non-significant, preference for Dutch over Frisian accents. Our results suggest a need for primary schools to explicitly address issues related to children’s attitudes towards different languages and accents

Emerging materials for transition: A taxonomy proposal from a design perspective

In response to environmental challenges, design promotes emerging materials connected with the circular economy and environmental sustainability. However, there is confusion about their definition and contribution to sustainable design and production, showing a gap in their classification. This article proposes a taxonomy as a helpful tool to consolidate and unify terminology, definitions and general understanding of these emerging materials. An analysis of 31 real-world case studies helped outline the taxonomic proposal to formalise knowledge, fostering clarity in classifying and identifying them. The taxonomy aims to organise emerging materials, generate reflections, and encourage their responsible development, diffusion, and adoption

Emerging materials fostering interdisciplinary collaboration in Materials Design

Materials Design is a recognized emerging and growing area in design practice and research that converges different fields and approaches to addressing a holistic perspective of materials in and for design. Therefore, it incorporates knowledge from various disciplines, like engineering and science. Direct interdisciplinary collaboration between engineers, scientists, artists and designers can benefit projects whose purpose is to bring innovation regarding materials and design. We assume this interdisciplinarity is a crucial practice for developing the emerging field of Materials Design with a sustainable and circular perspective. This article conveys the findings of an empirical collection of case studies on emerging materials and product design. The results demonstrate the sustainability and circularity orientations they present and different disciplinary cooperation to generate innovative outcomes. The authors examined ten European enterprises that present products driven by emerging materials from alternative sources to support the statement. The paper identifies and reflects on the importance and value of collaboration. It aims to disseminate knowledge about the field of Materials Design and intends to highlight that interdisciplinary collaboration in this area can be favourable for achieving a sustainable paradigm and more responsible production and consumption patterns