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1. Linking Nuclear Reactions and Nuclear Structure to Study Exotic Nuclei Using the Dispersive Optical Model

   https://doi.org/10.1007/978-3-030-58082-7_10  

   Dickhoff, W H (January 2021, Springer proceedings in physics)

   Escher, Jutta et (Ed.)

   The dispersive optical model (DOM) is employed to simultaneously describe elastic nucleon scattering data for 40Ca, 48Ca, and 208Pb as well as observables related to the ground state of these nuclei, with emphasis on the charge density. Such an analysis requires a fully non-local implementation of the DOM including its imaginary component. Illustrations are provided on how ingredients thus generated provide critical components for the description of the (d, p) and (e, e′p) reaction. For the nuclei with N > Z the neutron distribution is constrained by available elastic scattering and ground-state data thereby generating a prediction for the neutron skin. We identify ongoing developments including a non-local DOM analysis for 208Pb and point out possible extensions of the method to secure a successful extension of the DOM to rare isotopes. 

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2. Synthesis of Alkyl Aryl Ethers by O-Arylation of Alcohols with Diaryliodonium Salts: Scope, Limitations, and Mechanism

   https://doi.org/10.1055/a-2198-3637  

   Gallagher, Rory T; Jha, Soocheta; Metze, Bryan E; Stuart, David R (April 2024, Synlett)

   Abstract We describe the development of a C–O coupling reaction between aryl(2,4,6-trimethoxyphenyl)iodonium salts and aliphatic alcohols under weak base conditions. The scope of the reaction is presented, with 16 examples ranging in yield from moderate to high (54–96%). The limitations of the reaction are also presented. Mechanistic experiments reveal a complex network of reactions that include side reactions that generate arynes and oxidize the alcohol nucleophile. 

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3. Checking equivalence in a non-strict language

   https://doi.org/10.1017/S0956796825100099  

   KOLESAR, JOHN CHARLES; PISKAC, RUZICA; HALLAHAN, WILLIAM TRIEST (January 2025, Journal of Functional Programming)

   Abstract Program equivalence checking is the task of confirming that two programs have the same behavior on corresponding inputs. We develop a calculus based on symbolic execution and coinduction to check the equivalence of programs in a non-strict functional language. Additionally, we show that our calculus can be used to derive counterexamples for pairs of inequivalent programs, including counterexamples that arise from non-termination. We describe a fully automated approach for finding both equivalence proofs and counterexamples. Our implementation,nebula, proves equivalences of programs written in Haskell. We demonstratenebula’s practical effectiveness at both proving equivalence and producing counterexamples automatically by applyingnebulato existing benchmark properties. 

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4. Empirical Models of the Hβ Broad Emission Line Gas Density Field

   https://doi.org/10.3847/1538-4357/ad35cb  

   Villafaña, Lizvette; Treu, Tommaso; Colleyn, Lourenzo; Brewer, Brendon J.; Barth, Aaron J.; Malkan, Matthew A.; U, Vivian; Bennert, Vardha N. (April 2024, The Astrophysical Journal)

   Abstract We present the second iteration of thecaramel-gascode, an empirical model of the broad-line region (BLR) gas density field. Building on the initial development and testing ofcaramel-gas, we expand the meaning of the model parameterα, which initially represented only the power-law index of the dependency of emissivity on radial distance. In this work, we test a more generalized radial power-law index,α, that also includes a description of the effective emitting size(s) of the BLR structure as a function of radial distance. We select a sample of 10 active galactic nuclei (AGN) from three different Lick AGN Monitoring Project campaigns to further validate thecaramel-gascode and test the generalized radial power-law index,α. Our results confirm that thecaramel-gasresults are in general agreement with the published results determined using the originalcaramelcode, further demonstrating that our forward modeling method is robust. We find that a positive radial power-law index is generally favored and propose three possible scenarios: (i) the BLR structure has increasing effective emitting size(s) at larger radial distances from the central source, (ii) emission is concentrated at the outer edges of the BLR, and (iii) stronger theoretical assumptions are needed to break the degeneracies inherent to the interpretation of reverberation mapping data in terms of underlying gas properties. 

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5. Black hole perturbation theory and multiple polylogarithms

   https://doi.org/10.1007/JHEP11(2023)059  

   Aminov, Gleb; Arnaudo, Paolo; Bonelli, Giulio; Grassi, Alba; Tanzini, Alessandro (November 2023, Journal of High Energy Physics)

   A<sc>bstract</sc> We study black hole linear perturbation theory in a four-dimensional Schwarzschild (anti) de Sitter background. When dealing with apositivecosmological constant, the corresponding spectral problem is solved systematically via the Nekrasov-Shatashvili functions or, equivalently, classical Virasoro conformal blocks. However, this approach can be more complicated to implement for certain perturbations if the cosmological constant isnegative. For these cases, we propose an alternative method to set up perturbation theory for both small and large black holes in an analytical manner. Our analysis reveals a new underlying recursive structure that involves multiple polylogarithms. We focus on gravitational, electromagnetic, and conformally coupled scalar perturbations subject to Dirichlet and Robin boundary conditions. The low-lying modes of the scalar sector of gravitational perturbations and its hydrodynamic limit are studied in detail. 

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