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1. On an Equivalence of Divisors on $$\overline {\text {M}}_{0,n}$$ from Gromov-Witten Theory and Conformal Blocks

   https://doi.org/10.1007/s00031-022-09752-6  

   Chen, L.; Gibney, A.; Heller, L.; Kalashnikov, E.; Larson, H.; Xu, W. (August 2022, Transformation Groups)

   Abstract We consider a conjecture that identifies two types of base point free divisors on$$\overline {\text {M}}_{0,n}$$ ${\overline{M}}_{0,n}$. The first arises from Gromov-Witten theory of a Grassmannian. The second comes from first Chern classes of vector bundles associated with simple Lie algebras in type A. Here we reduce this conjecture on$$\overline {\text {M}}_{0,n}$$ ${\overline{M}}_{0,n}$to the same statement forn= 4. A reinterpretation leads to a proof of the conjecture on$$\overline {\text {M}}_{0,n}$$ ${\overline{M}}_{0,n}$for a large class, and we give sufficient conditions for the non-vanishing of these divisors. 

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2. Metal-ligand interactions in a redox active ligand system. Electrochemistry and spectroscopy of [M(dipyvd)2]n+ (M=Zn, Ni, n=0, 1, 2)

   https://doi.org/10.3389/fchem.2023.1295289  

   Fleming, Connor; Vu, Son; Brook, David_J R; Agrestini, Stefano; Pellegrin, Eric; DaRos, Jeffrey (November 2023, Frontiers in Chemistry)

   Reaction of nickel and zinc triflates with the tridentate leucoverdazyl 1-isopropyl-3,5-di (2′-pyridyl)-6-oxo-2H-tetrazine (dipyvdH) and triethylamine resulted in the neutral coordination compounds M(dipyvd)₂(M = Ni,Zn). In acetonitrile, both compounds undergo two one electron oxidation processes, Zn (dipyvd)₂ at −0.28 V and −0.12 V and Ni(dipyvd)₂ at −0.32 V and −0.15 V vs ferrocene/ferricenium. Oxidations are ligand based resulting in an intermediate mixed valence species and a cationic bis(verdazyl) compound respectively. Oxidation of the ligand changes a localized, antiaromatic, non-planar 8π electron anion to a planar, delocalized 7π electron radical. The change in ligand structure results in an increase in the octahedral ligand field splitting from 10,500 cm^–1to ∼13,000 cm^–1, suggesting an increase in the pi acceptor character of the ligand. In the mixed valence species, spectroscopic data suggests minimal interaction between ligands mediated by the metal center; i.e., these are class I-II systems in the Robin-Day classification. 

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3. Lazy tournaments and multidegrees of a projective embedding of \(\overline{M}_{0,n}\)

   https://doi.org/10.5070/C63160416  

   Gillespie, Maria; Griffin, Sean T.; Levinson, Jake (March 2023, Combinatorial Theory)
4. Protostellar Cores in Sagittarius B2 N and M

   https://doi.org/10.3847/1538-4357/ad0383  

   Budaiev, Nazar; Ginsburg, Adam; Jeff, Desmond; Goddi, Ciriaco; Meng, Fanyi; Sánchez-Monge, Álvaro; Schilke, Peter; Schmiedeke, Anika; Yoo, Taehwa (January 2024, The Astrophysical Journal)

   Abstract We present 500 and 700 au resolution 1 and 3 mm Atacama Large Millimeter/submillimeter Array observations, respectively, of protostellar cores in protoclusters Sagittarius B2 (Sgr B2) North (N) and Main (M), parts of the most actively star-forming cloud in our Galaxy. Previous lower-resolution (5000 au) 3 mm observations of this region detected ∼150 sources inferred to be young stellar objects (YSOs) withM> 8M_⊙. With a 10-fold increase in resolution, we detect 371 sources at 3 mm and 218 sources in the smaller field of view at 1 mm. The sources seen at low resolution are observed to fragment into an average of two objects. About one-third of the observed sources fragment. Most of the sources we report are marginally resolved and are at least partially optically thick. We determine that the observed sources are most consistent with Stage 0/I YSOs, i.e., rotationally supported disks with an active protostar and an envelope, that are warmer than those observed in the solar neighborhood. We report source-counting-based inferred stellar mass and the star formation rate of the cloud: 2800M_⊙and 0.0038M_⊙yr⁻¹for Sgr B2 N and 6900M_⊙and 0.0093M_⊙yr⁻¹for Sgr B2 M, respectively. 

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5. The eleventh cohomology group of $$\overline {\mathcal {M}}_{g,n}$$

   https://doi.org/10.1017/fms.2023.59  

   Canning, Samir; Larson, Hannah; Payne, Sam (January 2023, Forum of Mathematics, Sigma)

   Abstract We prove that the rational cohomology group$$H^{11}(\overline {\mathcal {M}}_{g,n})$$vanishes unless$$g = 1$$and$$n \geq 11$$. We show furthermore that$$H^k(\overline {\mathcal {M}}_{g,n})$$is pure Hodge–Tate for all even$$k \leq 12$$and deduce that$$\# \overline {\mathcal {M}}_{g,n}(\mathbb {F}_q)$$is surprisingly well approximated by a polynomial inq. In addition, we use$$H^{11}(\overline {\mathcal {M}}_{1,11})$$and its image under Gysin push-forward for tautological maps to produce many new examples of moduli spaces of stable curves with nonvanishing odd cohomology and nontautological algebraic cycle classes in Chow cohomology. 

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