We systematically generated large-scale data sets to improve genome annotation for the nematode Caenorhabditis elegans, a key model organism. These data sets include transcriptome profiling across a developmental time course, genome-wide identification of transcription factor–binding sites, and maps of chromatin organization. From this, we created more complete and accurate gene models, including alternative splice forms and candidate noncoding RNAs. We constructed hierarchical networks of transcription factor–binding and microRNA interactions and discovered chromosomal locations bound by an unusually large number of transcription factors. Different patterns of chromatin composition and histone modification were revealed between chromosome arms and centers, with similarly prominent differences between autosomes and the X chromosome. Integrating data types, we built statistical models relating chromatin, transcription factor binding, and gene expression. Overall, our analyses ascribed putative functions to most of the conserved genome.

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Tuning the macroscopic dielectric response on demand holds potential for actively tunable metaphotonics and optical devices. In recent years, graphene has been extensively investigated as a tunable element in nanophotonics. Significant theoretical work has been devoted on the tuning the hyperbolic properties of graphene/dielectric heterostructures, however, until now, such a motif has not been demonstrated experimentally. Here we focus on a graphene/polaritonic dielectric metamaterial, with strong optical resonances arising from the polar response of the dielectric, which are, in general, difficult to actively control. By controlling the doping level of graphene via external bias we experimentally demonstrate a wide range of tunability from a Fermi level of E F = 0 eV to E F = 0.5 eV, which yields an effective epsilon-near-zero crossing and tunable dielectric properties, verified through spectroscopic ellipsometry and transmission measurements.Spectral tunability is key for controlling light-matter interactions, critical for many applications including emission control, surface enhanced spectroscopy, sensing, and thermal control. Particularly in the subwavelength range, tuning plasmonic resonances has been essential in controlling color, typically achieved by controlling the size of plasmonic nanoparticles, antennas and metamaterials 1-4 . In obtaining a large range of spectral tunability, it is preferable to operate near an optical resonance rather than a broadband plasmonic response. Nevertheless, it is in general easier to tune a broadband optical response rather than a resonant one since resonances in nanophotonics typically entail subwavelength-scale geometrical features.From a very wide range of recently investigated metamaterials and heterostructures for spectral control, particular emphasis has been given to hyperbolic media, due to enhanced light-matter interactions arising from a larger range of wavenumbers available for propagating modes 5 . These media are in generally uniaxial and support a hyperbolic frequency dispersion given by the equation 3,6-8where ε o and ε e refer to the ordinary (in-plane) and extraordinary (out-of-plane) dielectric permittivity, respectively. Due to the different sign in ε o and ε e , upon fixing the frequency ω, the isofrequency diagram of the relevant electromagnetic modes opens up into a hyperbola, giving rise to a very large density of optical states, promising for waveguiding 9 , emission engineering and Purcell enhancement 1,2,10 thermal photonics 11 , lasing 12 , and imaging 13,14 . Particularly, near the epsilon-near-zero frequency crossing of either ε o or ε e , many exciting phenomena can be supported, the most prominent of which is light propagation with near-zero phase advance 15-17 . a) Present address:There has been significant effort in frequency-tuning of the optical response of hyperbolic metamaterials 6,18-20 . For this, particular interest holds the case of graphene, a wellstudied monolayer material for electronics 21 and in infrared photonics 22 . Namely...

We demonstrate pseudo single crystal, direct-band-gap Ge0.89Sn0.11 crystallized on amorphous layers at <450 °C towards 3D Si photonic integration. We developed two approaches to seed the lateral single crystal growth: (1) utilize the Gibbs-Thomson eutectic temperature depression at the tip of an amorphous GeSn nanotaper for selective nucleation; (2) laser-induced nucleation at one end of a GeSn strip. Either way, the crystallized Ge0.89Sn0.11 is dominated by a single grain >18 μm long that forms optoelectronically benign twin boundaries with others grains. These pseudo single crystal, direct-band-gap Ge0.89Sn0.11 patterns are suitable for monolithic 3D integration of active photonic devices on Si.

Highly textured Ge0.91Sn0.09 is obtained on both amorphous SiO2/Si and glass substrates at low temperatures <475 oC, which shows grain sizes up to tens of microns. Strikingly, the nucleation center spacing ranges from 0.1 to 1 mm, orders of magnitude larger than common solid state crystallization. This observation indicates an exceedingly high grain growth rate vs. a low nucleation rate. Therefore, we can control nucleation sites and fabricate geometrically confined pseudo single crystalline GeSn grain using patterning techniques, including surface Sn dots/patches, local laser annealing, and nanotaper patterns. Another remarkable result is that ~9 at.% Sn is incorporated substitutionally into Ge, far exceeding the equilibrium solubility limit of ~1 at.%. The high Sn composition, together with ~0.24% thermally induced tensile strain in the film, shifts the GeSn direct band gap to ~0.5 eV (2500nm) and converts it into a direct band gap semiconductor with significantly enhanced optoelectronic properties.