Inter-Group Relations and Support for Democratization: Evidence from Hong Kong

What drives ordinary citizens to participate in costly pro-democracy endeavors? Conventional theories of democratization emphasize the economic or political conflicts between citizens and elites. This article suggests a different mechanism of mobilization based on inter-group relations. We argue that as a pro-majoritarian institution, democracy may be sought after by members of a disenfranchised majority as a way to protect their interests and identity against perceived economic or political threats posed by certain minority outgroups. We evaluate this argument by drawing evidence from Hong Kong, a city that has recently witnessed major waves of pro-democracy uprisings. Two experimental studies on local university students reveal that subjects' attitudes toward the mainland Chinese visitors and immigrants are causally related to their support for democratization. Observational evidence from surveys and elections further shows that pro-democracy attitudes are stronger in areas that recently experienced a large influx of mainland Chinese. These findings underscore the powerful role of group-based sentiments in episodes of democratization.

A bimodal distribution of haze in Pluto’s atmosphere

Pluto, Titan, and Triton make up a unique class of solar system bodies, with icy surfaces and chemically reducing atmospheres rich in organic photochemistry and haze formation. Hazes play important roles in these atmospheres, with physical and chemical processes highly dependent on particle sizes, but the haze size distribution in reducing atmospheres is currently poorly understood. Here we report observational evidence that Pluto’s haze particles are bimodally distributed, which successfully reproduces the full phase scattering observations from New Horizons. Combined with previous simulations of Titan’s haze, this result suggests that haze particles in reducing atmospheres undergo rapid shape change near pressure levels ~0.5 Pa and favors a photochemical rather than a dynamical origin for the formation of Titan’s detached haze. It also demonstrates that both oxidizing and reducing atmospheres can produce multi-modal hazes, and encourages reanalysis of observations of hazes on Titan and Triton.

Nutrient consumption by diatoms in the dark subsurface layer of Funka Bay, Hokkaido, Japan

We conducted time-series observations in Funka Bay, Hokkaido, Japan, from 15 February to 14 April 2019. The diatom spring bloom peaked on 4 March and started declining on 15 March. Funka Bay winter water remained below 30-m depth, which was below the surface mixed-layer and dark-zone depths on both dates. At depths of 30–50 m, concentrations of NO3–, PO43–, and Si(OH)4 decreased by half between these dates even in darkness. Incubation experiments using the diatom Thalassiosira nordenskioeldii showed that this diatom could consume nutrients in darkness at substantial rates. We conclude that the nutrient reduction in the subsurface layer (30–50 m) could be explained by dark consumption by diatoms that had been growing in the surface waters and then sank to the subsurface layer. We believe that this is the first study to present observational evidence for the consumption of the main nutrients by diatoms in the dark subsurface layer during the spring bloom. Nutrient consumption in this layer might have a substantial influence on the primary production during and after the spring bloom.

Small Chunks, Deep Learning

Project I4 is a cohort-based, year-long program incorporating micro-credential experiences as a key element of learning for school leaders. The project focuses the micro-credential (MC) design, implementation, and study on a central aspect of a school leader's work: classroom observations and post-observation conversations. The leaders learn to observe academic discourse in STEM classrooms. To fully engage in the learning from the MC, leaders collect observational evidence on equitable instructional practices and use the evidence to have coaching post-observation conversations with teachers with the aim of changing instructional practices in classrooms. In the authors' model, a key component for the MC experiences is the opportunity for school leaders to work with leadership coaches in equity-centered networked improvement communities (EC-NICs) of 5-6 persons. This chapter presents a qualitative review of 10 school leaders from the first Project I4 cohort.

SDSS-IV MaNGA: Observational Evidence of a Density-bounded Region in a Lyα Emitter

Using integral field unit spectroscopy, we present here the spatially resolved morphologies of [S ii]λ6717,6731/Hα and [S ii]λ6717,6731/[O iii]λ5007 emission line ratios for the first time in a blueberry Lyα emitter (BBLAE) at z ∼ 0.047. Our derived morphologies show that the extreme starburst region of the BBLAE, populated by young (≤10 Myr), massive Wolf–Rayet stars, is [S ii] deficient, while the rest of the galaxy is [S ii] enhanced. We infer that the extreme starburst region is density-bounded (i.e., optically thin to ionizing photons), and the rest of the galaxy is ionization-bounded, indicating a Blister-type morphology. We find that the previously reported small escape fraction (10%) of Lyα photons is from our identified density-bounded H ii region of the BBLAE. This escape fraction is likely constrained by a porous dust distribution. We further report a moderate correlation between [S ii] deficiency and inferred Lyman continuum (LyC) escape fraction using a sample of confirmed LyC leakers studied in the literature, including the BBLAE studied here. The observed correlation also reveals its dependency on the stellar mass and gas-phase metallicity of the leaky galaxies. Finally, the future scope and implications of our work are discussed in detail.

Probes of the progenitors, engines and physics behind stellar collapse

Super-novas (SNs) are one of the most powerful explosions in the universe and astronomers have invoked the collapse of a stellar core down to a neutron star as a potential power source behind these cosmic blasts. The current paradigm behind core-collapse SN relies on convection in the region just above the newly formed neutron star. This engine was driven and confirmed by observations. We review this observational evidence, and the potential for further observational constraints in this paper.

Chemically Fresh Gas Inflows Detected in a Nearby High-mass Star-forming Region

We report the detection of a chemically fresh inflow that is feeding high-mass young-stellar-object (HMYSO) growth in the nearby high-mass star-forming region G352.63 made with both the Atacama Large Millimeter/submillimeter Array (ALMA) and the Submillimeter Array (SMA). High-quality images of the dust and molecular lines from both ALMA and SMA have consistently revealed a gravitationally controlled cold (∼10 K) gas inflow of chemically fresh molecules (e.g., CCH and HC3N) toward the central HMYSO and its surrounding dense gas structure, which has a possible torus- or disk-like morphology. The HMYSO is also observed to have an outflow, which is nearly perpendicular to the torus and its parental filament, and thus can be clearly separated from the inflows. These kinematic features provide observational evidence to support the conjecture that the infalling streamers in high-mass star-forming regions could proceed in a similar process to that observed in low-mass counterparts. The chemically fresh infalling streamers could also be involved in the disk or torus configuration, fragmentation, and accretion bursts that occur in both simulations and observations.