Plasmonic nanostructures hold promise for the realization of ultra-thin sub-wavelength devices, reducing power operating thresholds and enabling nonlinear optical functionality in metasurfaces. ...However, this promise is substantially undercut by absorption introduced by resistive losses, causing the metasurface community to turn away from plasmonics in favour of alternative material platforms (e.g., dielectrics) that provide weaker field enhancement, but more tolerable losses. Here, we report a plasmonic metasurface with a quality-factor (Q-factor) of 2340 in the telecommunication C band by exploiting surface lattice resonances (SLRs), exceeding the record by an order of magnitude. Additionally, we show that SLRs retain many of the same benefits as localized plasmonic resonances, such as field enhancement and strong confinement of light along the metal surface. Our results demonstrate that SLRs provide an exciting and unexplored method to tailor incident light fields, and could pave the way to flexible wavelength-scale devices for any optical resonating application.
Symbiotic mutualisms are thought to be stabilized by correlations between the interacting genotypes which may be strengthened via vertical transmission and/or reduced genetic variability within each ...species. Vertical transmission, however, may weaken interactions over time as the endosymbionts would acquire mutations that could not be purged. Additionally, temporal variation in a conditional mutualism could create genetic variation and increased variation in the interaction outcome. In this study, we assessed genetic variation in both members of a symbiosis, the endosymbiotic fungal endophyte
Epichloë canadensis
and its grass host Canada wildrye (
Elymus canadensis
). Both species exhibited comparable levels of diversity, mostly within populations rather than between. There were significant differences between populations, although not in the same pattern for the two species, and the differences were not correlated with geographic distance for either species. Interindividual genetic distance matrices for the two species were significantly correlated, although all combinations of discriminant analysis of principle components (DAPC) defined multilocus genotype groups were found suggesting that strict genotype matching is not necessary. Variation in interaction outcome is common in grass/endophyte interactions, and our results suggest that the accumulation of mutations overtime combined with temporal variation in selection pressures increasing genetic variation in the symbiosis may be the cause.
This article attempts to place the emergence of probabilistic numerics as a mathematical–statistical research field within its historical context and to explore how its gradual development can be ...related both to applications and to a modern formal treatment. We highlight in particular the parallel contributions of Sul
′
din and Larkin in the 1960s and how their pioneering early ideas have reached a degree of maturity in the intervening period, mediated by paradigms such as average-case analysis and information-based complexity. We provide a subjective assessment of the state of research in probabilistic numerics and highlight some difficulties to be addressed by future works.
Romantic jealousy, a complex response to a real or perceived threat to a romantic relationship, can have serious negative consequences for individuals, partners and perceived rivals. The likelihood ...of a jealous response is heightened among individuals who experience attachment anxiety, and online communication and social media provide unique fodder for romantic jealousy. The purpose of the current study is to test whether the association between attachment anxiety and online jealousy (jealous response to ambiguous hypothetical online scenarios) is moderated by negative attitudes about online communication. Individuals in dating relationships were asked about attachment anxiety and attitudes about online communication (i.e., apprehension and concern about misunderstandings) as well as emotional, cognitive, and behavioral online jealousy. Hierarchical linear regression revealed an attachment anxiety-attitude interaction, such that the link between attachment anxiety and jealousy was stronger for participants with relatively low levels of negative attitudes about online communication compared to participants with relatively high levels of negative attitudes. The current study expands knowledge about attachment anxiety and jealousy in the context of online communication and social media, and highlights the importance of considering attitudes about online communication when studying relationship processes in the digital arena.
The 19 species of Dendroctonus bark beetles native to North America include several of the most significant biotic mortality agents of conifers in this region, and they have impacted millions of ...hectares of forest in recent decades. Semiochemical attractants play several vital roles in the biology of these insects including host finding, host assessment, and mate finding. They are key to the virulence of these insects, since they mediate the mass attacks that enable killing and reproduction within healthy trees. These attractants consist of combinations of thirteen identified pheromone components in three primary chemical classes and at least ten host-associated compounds dominated by monoterpene hydrocarbons in host defensive resin. Due to their potential for use in pest management technologies, semiochemical attractants for Dendroctonus have received extensive research into their chemical compositions and effects on insect behavior. This paper is intended as a synthesis of this research over the past 60 years as well as a critical examination of approaches to investigation of this topic and interpretation of experimental results. Its purpose is to assist practitioners in formulating suitable attractive lures for use in applications and identify gaps in knowledge of the semiochemistry of Dendroctonus that should be addressed if the practical potential of attractants is to be fully realized.
A strong mode of a probability measure on a normed space X can be defined as a point u such that the mass of the ball centred at u uniformly dominates the mass of all other balls in the small-radius ...limit. Helin and Burger weakened this definition by considering only pairwise comparisons with balls whose centres differ by vectors in a dense, proper linear subspace E of X, and posed the question of when these two types of modes coincide. We show that, in a more general setting of metrisable vector spaces equipped with measures that are finite on bounded sets, the density of E and a uniformity condition suffice for the equivalence of these two types of modes. We accomplish this by introducing a new, intermediate type of mode. We also show that these modes can be inequivalent if the uniformity condition fails. Our results shed light on the relationships between among various notions of maximum a posteriori estimator in non-parametric Bayesian inference.
► A new Direct DBD methodology is proposed for MRF structures with viscous dampers. ► The approach offers practitioners a simplified, non-iterative seismic design method. ► The proportions of force ...carried by dampers are selected to control damping. ► NLTH analyses of a 9-storey MRF building suggest that procedure performs well.
In this paper a new methodology for the Direct displacement-based seismic design (DBD) of moment resisting frame (MRF) structures fitted with viscous dampers is proposed. The approach builds on previous recommendations for Direct DBD and gives the designer a simplified non-iterative means of controlling the system damping of the structures by choosing proportions of force resisted by the dampers relative to the main structure. Non-linear time-history analyses of a 9-storey case study structure fitted with linear viscous dampers illustrate that the new procedure may prove to be very useful for design. Future research should aim to better verify the approach and extend it to the use of frames possessing non-linear viscous dampers.
The influence of surface topography (surface relief) on biofouling and cell settlement has been widely examined in the search for novel marine antifouling materials. Effects of surface topography on ...biofilms are, however, most commonly reported for laboratory experiments only. Marine diatoms are a particularly problematic group of biofouling organisms, and marine raphid diatom species are commonly used in conjunction with other assays to assess antifouling efficacy in laboratory studies. The effects of topographically structured materials on natural marine diatom fouling communities in field experiments are less commonly reported. Here, we report a number observations on the effects of microstructures created in poly(dimethylsiloxane) on diatom settlement in static field trials. It can be concluded that the effects of microscale surface topography on initial natural diatom settlement under static conditions in field tests depend upon the size, shape, adhesion strategy of the biofouling diatom species. Furthermore, while the topography of the underlying surface may influence the kinetics of cell settlement in laboratory tests, these effects can be masked by the effects of cell/mucilage aggregates and the diversity of settling cells in the natural marine environment.
Our understanding of gene regulation in plants is constrained by our limited knowledge of plant cis-regulatory DNA and its dynamics. We mapped DNase I hypersensitive sites (DHSs) in A. thaliana ...seedlings and used genomic footprinting to delineate ∼700,000 sites of in vivo transcription factor (TF) occupancy at nucleotide resolution. We show that variation associated with 72 diverse quantitative phenotypes localizes within DHSs. TF footprints encode an extensive cis-regulatory lexicon subject to recent evolutionary pressures, and widespread TF binding within exons may have shaped codon usage patterns. The architecture of A. thaliana TF regulatory networks is strikingly similar to that of animals in spite of diverged regulatory repertoires. We analyzed regulatory landscape dynamics during heat shock and photomorphogenesis, disclosing thousands of environmentally sensitive elements and enabling mapping of key TF regulatory circuits underlying these fundamental responses. Our results provide an extensive resource for the study of A. thaliana gene regulation and functional biology.
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•A. thaliana regulatory DNA, TF footprints, and cis-regulatory lexicon are elucidated•TF binding in protein-coding exons may have shaped A. thaliana codon usage•A. thaliana TF network architecture is strikingly similar to human•Light- and heat-cued regulatory DNA dynamics and TF network remodeling are revealed
Our understanding of plant gene regulation is constrained by our limited knowledge of plant cis-regulatory DNA and its dynamics in response to environmental cues. Sullivan et al. now establish nucleotide-resolution regulatory DNA landscapes for A. thaliana seedlings before and after exposure to light and heat, key environmental cues shaping plant growth and development. This study generates genome-wide, condition- and tissue-specific maps of TF occupancy, constructs condition-specific TF networks, and identifies hundreds of de novo TF motif models.
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