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1. The time-scales probed by star formation rate indicators for realistic, bursty star formation histories from the FIRE simulations

   https://doi.org/10.1093/mnras/staa3893  

   Flores Velázquez, José A ; Gurvich, Alexander B ; Faucher-Giguère, Claude-André ; Bullock, James S ; Starkenburg, Tjitske K ; Moreno, Jorge ; Lazar, Alexandres ; Mercado, Francisco J ; Stern, Jonathan ; Sparre, Martin ; et al ( January 2021 , Monthly Notices of the Royal Astronomical Society)

   null (Ed.)

   ABSTRACT Understanding the rate at which stars form is central to studies of galaxy formation. Observationally, the star formation rates (SFRs) of galaxies are measured using the luminosity in different frequency bands, often under the assumption of a time-steady SFR in the recent past. We use star formation histories (SFHs) extracted from cosmological simulations of star-forming galaxies from the FIRE project to analyse the time-scales to which the H α and far-ultraviolet (FUV) continuum SFR indicators are sensitive. In these simulations, the SFRs are highly time variable for all galaxies at high redshift, and continue to be bursty to z = 0 in dwarf galaxies. When FIRE SFHs are partitioned into their bursty and time-steady phases, the best-fitting FUV time-scale fluctuates from its ∼10 Myr value when the SFR is time-steady to ≳100 Myr immediately following particularly extreme bursts of star formation during the bursty phase. On the other hand, the best-fitting averaging time-scale for H α is generally insensitive to the SFR variability in the FIRE simulations and remains ∼5 Myr at all times. These time-scales are shorter than the 100 and 10 Myr time-scales sometimes assumed in the literature for FUV and H α, respectively, because while the FUV emission persists for stellar populations older than 100 Myr, the time-dependent luminosities are strongly dominated by younger stars. Our results confirm that the ratio of SFRs inferred using H α versus FUV can be used to probe the burstiness of star formation in galaxies. 

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2. Distortion of the [FeNO] 2 Core in Flavodiiron Nitric Oxide Reductase Models Inhibits N–N Bond Formation and Promotes Formation of Unusual Dinitrosyl Iron Complexes: Implications for Catalysis and Reactivity

   https://doi.org/10.1021/jacs.1c10388  

   White, Corey J. ; Lengel, Michael O. ; Bracken, Abigail J. ; Kampf, Jeff W. ; Speelman, Amy L. ; Alp, E. Ercan ; Hu, Michael Y. ; Zhao, Jiyong ; Lehnert, Nicolai ( March 2022 , Journal of the American Chemical Society)
3. CALCITE MINERALOGY FROM THE NASHUA FORMATION, FORT DRUM, AND FORT THOMPSON FORMATION, NORTH FORT MYERS, FLORIDA. AN NSF GEOPATH AND MRI FUNDED STUDY

   https://doi.org/10.1130/abs/2022NC-375047  

   Piquiet, Megan ; Molina, Richard ; Morejon, Sophia ; Roberts, Brandon ; Jerew, Hailey R. ; MacDonald, James ; Barbosa, Alli ; McManus, Gregory J. ( January 2022 , Geological Society of America Abstracts with Programs)
4. Star formation at the edge of the Local Group: a rising star formation history in the isolated galaxy WLM

   https://doi.org/10.1093/mnras/stz2903  

   Albers, Saundra M ; Weisz, Daniel R ; Cole, Andrew A ; Dolphin, Andrew E ; Skillman, Evan D ; Williams, Benjamin F ; Boylan-Kolchin, Michael ; Bullock, James S ; Dalcanton, Julianne J ; Hopkins, Philip F ; et al ( December 2019 , Monthly Notices of the Royal Astronomical Society)

   ABSTRACT We present the star formation history (SFH) of the isolated (D ∼ 970 kpc) Local Group dwarf galaxy Wolf–Lundmark–Melotte (WLM) measured from colour–magnitude diagrams (CMDs) constructed from deep Hubble Space Telescope imaging. Our observations include a central ($0.5 \, r_h$) and outer field ($0.7 \, r_h$) that reach below the oldest main-sequence turn-off. WLM has no early dominant episode of star formation: 20 per cent of its stellar mass formed by ∼12.5 Gyr ago ($z$ ∼ 5). It also has an SFR that rises to the present with 50 per cent of the stellar mass within the most recent 5 Gyr ($z$ < 0.7). There is evidence of a strong age gradient: the mean age of the outer field is 5 Gyr older than the inner field despite being only 0.4 kpc apart. Some models suggest such steep gradients are associated with strong stellar feedback and dark-matter core creation. The SFHs of real isolated dwarf galaxies and those from the Feedback in Realistic Environment suite are in good agreement for M⋆($z$ = 0) ∼ 107–109M⊙, but in worse agreement at lower masses ($M_{\star }(z=0) \sim 10^5\!-\!10^7 \, \mathrm{M}_{\odot }$). These differences may be explainable by systematics in the models (e.g. reionization model) and/or observations (HST field placement). We suggest that a coordinated effort to get deep CMDs between HST/JWST (crowded central fields) and WFIRST (wide-area halo coverage) is the optimal path for measuring global SFHs of isolated dwarf galaxies. 

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5. When Optimal Team Formation is a Choice - Self-Selection versus Intelligent Team Formation Strategies in a Large Online Project-Based Course

   Sankaranarayanan, S. ( June 2018 , Proceedings of AI in Education)

   Prior research in Team-Based Massive Open Online Project courses (TB-MOOPs) has demonstrated both the importance of effective group composition and the potential for using automated methods for forming effective teams. Past work on automated team assignment has produced both spectacular failures and spectacular successes. In either case, different contexts pose particular challenges that may interfere with the applicability of approaches that have succeeded in other contexts. This paper reports on a case study investigating the applicability of an automated team assignment approach that has succeeded spectacularly in TB-MOOP contexts to a large online project-based course. The analysis offers both evidence of partial success of the paradigm as well as insights into areas for growth. 

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