Article describes how weak emission-line quasars (WLQs) are a subset of Type 1 quasars that exhibit extremely weak Lyα+N V λ1240 and/or C IV λ1549 emission lines. The authors investigate the relationship between emission-line properties and accretion rate for a sample of 230 `ordinary' Type 1 quasars and 18 WLQs at z<0.5 and 1.5<z<3.5 that have rest-frame ultraviolet and optical spectral measurements.

Discusses a project in which researchers were able to generate over 1000 diffraction spots from a graded photonic super-crystal with a unit super-cell size of 12a × 12a where a is the lattice constant and hole radii are gradually changed in dual directions.

Authors of the article use analytical results for viscous dissipation in phononic crystals to calculate the decay coefficient of a sound wave propagating at low frequencies through a two-dimensional phononic crystal with a viscous fluid background. They claim that the decay coefficient exhibits dependence on the direction of propagation; that is, a homogenized phononic crystal behaves like an anisotropic viscous fluid.

Article describes how metal-organic frameworks (MOFs) are porous crystalline materials, and their large pores make them particularly interesting for membranes, gas separation, and gas storage. The authors discuss how gas-MOF interactions alter the MOFs' spectral fingerprints.

Article describes how biophotons are an ultra-weak emission of photons in the visible energy range from living matter. The authors study the emission from germinating seeds using an experimental technique designed to detect light of extremely small intensity.