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1. The role of states in U.S. immigration: A study of population dynamics and subnational immigration laws

   https://doi.org/10.1016/j.ssresearch.2023.102909  

   Anadón, Isabel J (August 2023, Social Science Research)

   Legislative action on issues of immigration emerged prominently across and within US states throughout the 2000s. The emerging literature on this topic demonstrates the political motivations driving anti-immigrant laws that negatively impact the mobility of Hispanic/Latino and Foreign-born populations across US states. Considerable research identifies the political mechanisms driving restrictive state-level immigration policies. Despite the growth of this scholarly work, the impact of these laws within states requires further study. This paper broadens the approach to the study of restrictive state-level omnibus immigration laws (OILs) using a rich dataset to uncover the effects of these laws on compositional change for undocumented, foreign-born, and Hispanic/Latino populations from 2005 to 2017. Using a quasi-experimental design, I show that by passing omnibus immigration laws, states shape demographic patterns of Foreign-born populations. Specifically, I find that states that pass omnibus immigration laws experience a decrease in undocumented and Foreign-born populations relative to states that did not pass similar laws. Effects are estimated each year after the passage of OILs, providing additional insight into the temporal impact of omnibus immigration laws on the settlement patterns of these groups. I conclude by discussing the theoretical implications of the multiple interior immigration law and policies, specifically at the state level, and their salience in shaping population dynamics across the United States. 

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2. Asymptotically nonlocal gravity

   https://doi.org/10.1007/JHEP06(2023)017  

   Boos, Jens; Carone, Christopher D. (June 2023, Journal of High Energy Physics)

   A bstract Asymptotically nonlocal field theories interpolate between Lee-Wick theories with multiple propagator poles, and ghost-free nonlocal theories. Previous work on asymp- totically nonlocal scalar, Abelian, and non-Abelian gauge theories has demonstrated the existence of an emergent regulator scale that is hierarchically smaller than the lightest Lee-Wick partner, in a limit where the Lee-Wick spectrum becomes dense and decoupled. We generalize this construction to linearized gravity, and demonstrate the emergent regula- tor scale in three examples: by studying the resolution of the singularity (i) at the origin in the classical solution for the metric of a point particle, and (ii) in the nonrelativistic gravitational potential computed via a one-graviton exchange amplitude; (iii) we also show how this derived scale regulates the one-loop graviton contribution to the self energy of a real scalar field. We comment briefly on the generalization of our approach to the full, nonlinear theory of gravity. 

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3. Genomic Basis of Convergent Island Phenotypes in Boa Constrictors

   https://doi.org/10.1093/gbe/evz226  

   Card, Daren C; Adams, Richard H; Schield, Drew R; Perry, Blair W; Corbin, Andrew B; Pasquesi, Giulia I; Row, Kristopher; Van Kleeck, Melissa J; Daza, Juan M; Booth, Warren; et al (November 2019, Genome Biology and Evolution)

   Abstract Convergent evolution is often documented in organisms inhabiting isolated environments with distinct ecological conditions and similar selective regimes. Several Central America islands harbor dwarf Boa populations that are characterized by distinct differences in growth, mass, and craniofacial morphology, which are linked to the shared arboreal and feast-famine ecology of these island populations. Using high-density RADseq data, we inferred three dwarf island populations with independent origins and demonstrate that selection, along with genetic drift, has produced both divergent and convergent molecular evolution across island populations. Leveraging whole-genome resequencing data for 20 individuals and a newly annotated Boa genome, we identify four genes with evidence of phenotypically relevant protein-coding variation that differentiate island and mainland populations. The known roles of these genes involved in body growth (PTPRS, DMGDH, and ARSB), circulating fat and cholesterol levels (MYLIP), and craniofacial development (DMGDH and ARSB) in mammals link patterns of molecular evolution with the unique phenotypes of these island forms. Our results provide an important genome-wide example for quantifying expectations of selection and convergence in closely related populations. We also find evidence at several genomic loci that selection may be a prominent force of evolutionary change—even for small island populations for which drift is predicted to dominate. Overall, while phenotypically convergent island populations show relatively few loci under strong selection, infrequent patterns of molecular convergence are still apparent and implicate genes with strong connections to convergent phenotypes. 

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4. Electron-scale dynamics of the diffusion region during symmetric magnetic reconnection in space

   https://doi.org/10.1126/science.aat2998  

   Torbert, R. B.; Burch, J. L.; Phan, T. D.; Hesse, M.; Argall, M. R.; Shuster, J.; Ergun, R. E.; Alm, L.; Nakamura, R.; Genestreti, K. J.; et al (December 2018, Science)

   Magnetic reconnection is an energy conversion process that occurs in many astrophysical contexts including Earth’s magnetosphere, where the process can be investigated in situ by spacecraft. On 11 July 2017, the four Magnetospheric Multiscale spacecraft encountered a reconnection site in Earth’s magnetotail, where reconnection involves symmetric inflow conditions. The electron-scale plasma measurements revealed (i) super-Alfvénic electron jets reaching 15,000 kilometers per second; (ii) electron meandering motion and acceleration by the electric field, producing multiple crescent-shaped structures in the velocity distributions; and (iii) the spatial dimensions of the electron diffusion region with an aspect ratio of 0.1 to 0.2, consistent with fast reconnection. The well-structured multiple layers of electron populations indicate that the dominant electron dynamics are mostly laminar, despite the presence of turbulence near the reconnection site. 

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5. Some Optimally Convergent Algorithms for Decoupling the Computation of Biot’s Model

   https://doi.org/10.1007/s10915-023-02365-5  

   Cai, Mingchao; Gu, Huipeng; Li, Jingzhi; Mu, Mo (November 2023, Journal of Scientific Computing)

   We study numerical algorithms for solving Biot’s model. Based on a three-field reformulation, we present some algorithms that are inspired by the work of Chaabane et al. (Comput MathAppl 75(7):2328–2337) and Lee (Unconditionally stable second order convergent partitioned methods for multiple-network poroelasticity arXiv:1901.06078, 2019) for decoupling the computation of Biot’s model. A new theoretical framework is developed to analyze the algorithms. Considering a uniform temporal discretization, these algorithms solve the coupled model on the first time level. On the remaining time levels, one algorithm solves a reaction-diffusion subproblem first and then solves a generalized Stokes subproblem.Another algorithm reverses the order of solving the two subproblems. Our algorithms manage to decouple the numerical computation of the coupled system while retaining the convergence properties of the original coupled algorithm. Theoretical analysis is conducted to show that these algorithms are unconditionally stable and optimally convergent.Numerical experiments are also carried out to validate the theoretical analysis and demonstrate the advantages of the proposed algorithms. 

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