This commentary is part of a series of responses to Michele Goodwin’s 2025 LSA presidential address.

Distributed ledgers, including blockchain and other decentralized databases, are designed to store information online where all trusted network members can update the data with transparency. The dynamics of a ledger’s development can be mathematically represented by a directed acyclic graph (DAG). In this paper, we study a DAG model that considers batch arrivals and random delay of attachment. We analyze the asymptotic behavior of this model by letting the arrival rate go to infinity and the inter-arrival time go to zero. We establish that the number of leaves in the DAG, as well as various random variables characterizing the vertices in the DAG, can be approximated by its fluid limit, represented as the solution to a set of delayed partial differential equations. Furthermore, we establish the stable state of this fluid limit and validate our findings through simulations.

The northeastern Arabian Peninsula has an extreme arid climate. To establish past variations in precipitation intensity during the late Quaternary, the oxygen isotope ratios (δ18O) of meteoric calcite cements of the late Quaternary aeolianites of the Ghayathi Formation in Abu Dhabi and Dubai have been analysed. The Ghayathi Formation is a carbonate-rich aeolianite, stabilised by calcite cement precipitated from rising groundwater during humid intervals. The calcite cements are well developed inside and outside a thin micrite rim of now hollow grains, formed by leaching of unstable carbonate grains. The δ18O values of cement analysed in thin sections by secondary ion mass spectrometry vary from −9.1‰ (VPDB) in coastal to +12.7‰ (VPDB) inland areas. This exceptionally wide range of the otherwise petrographically uniform aeolianite is due to the contrasts in humidity and evaporation rate between the coastal and inland areas. The δ18O values as low as −9.1‰ suggest intense precipitation in the late Quaternary, possibly due to the northward expansion of the intertropical convergence zone and intensified Indian summer monsoon. The exceptionally high values must be due to intense evaporation at low humidity in low-salinity, playa-type environments during intermittent arid intervals.

The Great Depression in 1929 had a transformative impact on Turkey. The institutions established to minimize the effects of the crisis propagated a set of statist measures. The National Economy and Savings Association and Public Press Directorate utilized photography and painting in the beginning of the 1930s to propagate those measures. In their efforts, these institutions constructed a new conception of landscape with a moral agenda: citizens and artists should travel in Anatolia to learn about the country, love it, and create art accordingly. Key to this conception was the productivity of the land. The most comprehensive cultural program during World War II, Homeland Tours, mimicked this new conception of a landscape. This article analyzes the conception of productive landscapes up until the end of World War II by drawing attention to the overlooked photography collection in the State Archives, which comprises paintings made during the Homeland Tours. One of the many tools that the statist economic institutions devised was agricultural statistics. The comparison between the paintings and actual land use statistics demonstrates that the artists collectively followed the statist economic agenda.

Multilevel modeling accounts for outcome dependence across lower-level units due to unobserved group effects, while spatial modeling accounts for outcome dependence across units in the same level of analysis due to diffusion. Outcome dependence can occur simultaneously due to both spatial diffusion in the lower-level units and spatial diffusion in the unobserved group effects. For example, counties are nested within states and diffusion processes might take place at both levels of analysis. Building on recent research from the spatial econometrics and multilevel modeling literature, we propose a class of spatial hierarchical models with binary outcomes. One method accounts for spatially independent, unobserved group effects and the other method accounts for spatially dependent unobserved group effects. We propose a Bayesian approach to estimate such effects while also accounting for lower-level diffusion in the outcome, and provide software to estimate these models. Our Monte Carlo results demonstrate that failing to correctly account for diffusion and/or the nested structure of data can lead to bias in both parameter estimates and substantive effects. We apply these models to analyze the causes of civil rights protests in the United States in the 1960s.

To date, there are no records of appendicularian assemblages or associated investigations in the waters adjacent to the Kuroshio Current around the Nansei Islands, Japan. In this study, plankton samplings were conducted with a North Pacific Standard net hauled vertically from a depth of 200 m to the surface to investigate the appendicularian community structure in such waters. Five species were newly recorded in the western North Pacific, each representing a new geographical record for the region. The new records include Fritillaria aequatorialis, Fritillaria pacifica, Fritillaria pellucida omani, Appendicularia tregouboffi, and Kowalevskia oceanica, which belong to appendicularian families Fritillariidae and Kowalevskiidae. Among them, F. aequatorialis, A. tregouboffi, and K. oceanica represent the first records in the entire Pacific Ocean. Owing to the under sampling of appendicularian assemblages in tropical and subtropical waters in the Pacific Ocean and a lack of systematic quantitative and qualitative research on this topic, these species might have been overlooked for a long time in Japanese waters.

Let $\mathbb {N}$ be the set of all nonnegative integers. For a set $A\subseteq \mathbb {N}$, let $R_2(A,n)$ and $R_3(A,n)$ be the number of solutions of the equation $n=a_1+a_2$ with $a_1<a_2, a_1,a_2\in A$ and with $a_1\le a_2, a_1,a_2\in A$, respectively. If $-N\le g\le N$, Yan [‘On the structure of partition which the difference of their representation function is a constant’, Period. Math. Hungar. 82 (2021), 149–152] showed that there is a set $A\subseteq \mathbb {N}$ such that $R_i(A,n)-R_i(\mathbb {N}\setminus A,n)=g$ for all integers $n\ge 2N-1$, where N is a positive integer. In this paper, we prove that if $g_1,g_2$ are nonnegative integers with $g_1\neq g_2$, then there does not exist $A\subseteq \mathbb {N}$ such that $R_i(A,2n)-R_i(\mathbb {N}\setminus A,2n)=g_1$ and $R_i(A,2n+1)-R_i(\mathbb {N}\setminus A,2n+1)=g_2$ for all sufficiently large integers n.

D-band waveguide transitions that combine a resonant patch on the printed circuit board with multiple waveguide irises are presented and shown to achieve a relative bandwidth of up to 35%. The irises implement an impedance-matching network that is described by a lumped-element circuit model. Parametric sweeps and Monte Carlo simulations quantify the influence of iris dimensions and manufacturing tolerances. The transitions’ group delay is characterized, and its influence on time-domain signals is demonstrated. As an application example, a transition design with six irises is integrated into a multichannel radar frontend with $40\,\mathrm{GHz}$ bandwidth, and measured range profiles are presented. The derived design guidelines enable straightforward customization of iris-based transitions for various applications and frequency bands.

The framing of the 2015 Rachel Dolezal transracialism scandal as a new kind of “trans moment” relies on a peculiar understanding of transness and Blackness, and the relationship they share. In this article, I analyze the “trans grammar” that structures this post-Dolezalian transracialism discourse, seeking to understand its points of reference in, and implications for, theories of transness and Blackness. I argue the post-Dolezalian transracialism discourse evidences a concern amongst Black trans feminists that the institutionalization of a “trans” concept that indexes always and only a normative figuration of “transgender” is reliant on the abstraction of the racialization of gendered space, and the erasure of Black trans feminist genealogies. I analyze the debate’s use of “trans” as a prefix for descriptors of the phenomenon Dolezal has come to represent and find the most prevalent usages create “trans” as a qualifier that is emptied of conceptual significance and political investments. This grammar, I argue, captures both Blackness and transness as fixed and knowable. Ultimately, the analysis builds an argument that the discourses’ dominant trans grammars rely on and reproduce a deficient theorization of racialized and gendered identities that depoliticizes transness and recreates gendered and Black identities as a priori and immutable.

The planar Skorokhod embedding problem was first proposed and solved by Gross [‘A conformal Skorokhod embedding’, Electron. Commun. Probab. 24 (2019), 11 pages; doi:10.1214/19-ECP272]. Gross worked with probability distributions having finite second moment. Boudabra and Markowsky [‘Remarks on Gross’ technique for obtaining a conformal Skorokhod embedding of planar Brownian motion’, Electron. Commun. Probab. 25 (2020), 13 pages; doi:10.1214/20-ECP300] extended the solution to all distributions with a finite pth moment for $p>1$. The case $p=1$ has remained uncovered since then. In this note, we show that the planar Skorokhod embedding problem is solvable for $p=1$ when the Hilbert transform of its quantile function is integrable, effectively closing this line of investigation.

Efficient memory management is essential for the stability and long-term performance of mobile robots in Simultaneous Localization and Mapping (SLAM). However, existing methods often struggle to control redundancy in keyframes and map points, leading to reduced efficiency, increased latency, and potential system failure due to resource constraints. Achieving high accuracy in both mapping and trajectory estimation while maintaining a compact state representation remains a key challenge for scalable and efficient SLAM systems. To address this issue, this paper proposes an efficient long-term visual SLAM method based on sparse prior embedding and nonlinear score-guided sparsification for memory-constrained environments. The approach embeds keyframe information into sparse prior factors, avoiding global coupling while preserving system sparsity and consistency. Additionally, a nonlinear scoring function combining parallax and descriptor uniqueness is introduced to guide map point sparsification within the sliding window. This strategy enables efficient state graph management, achieving compact global map representations and effective observation constraints. The proposed method has been implemented in a complete visual SLAM system and evaluated through long-term real-world mapping experiments on an embedded robotic platform. Experimental results demonstrate that the approach significantly reduces memory consumption while maintaining trajectory and mapping accuracy. Furthermore, the method ensures real-time execution and deployment potential, indicating its suitability for large-scale SLAM tasks in resource-constrained and long-duration operational scenarios.

We report a rare case of truncus arteriosus arising exclusively from the right ventricle associated with a restrictive inlet-type ventricular septal defect. Three-dimensional reconstruction provided essential spatial understanding for operative planning and highlights the morphological variability of conotruncal development.

This article re-evaluates the late seventeenth-century operatic culture of the Savoy court in Turin through the lens of newly examined archival material, the Avvisi di Torino preserved in the Medici archive in Florence. These handwritten newsletters, covering the years 1688–99, offer unprecedented insights into the musical and theatrical life of the Savoy capital, a court that stood at the crossroads of the Italian and French traditions. Previous scholarship has often overlooked this period or has relied primarily on printed librettos that provide only a partial view of operatic production. By integrating the avvisi with other sources, this study reconstructs the repertory, organization, and sociopolitical function of operatic spectacles under Victor Amadeus II of Savoy.

Let $\lambda (G)$ be the maximum number of subgroups in an irredundant cover of the finite group G. We establish bounds on the order, exponent and derived length of the group in terms of this invariant.

In 1970, Apostol introduced the Möbius function of order k for an integer $k\ge 1$. In 2001, it was generalized by Bege to the Möbius function $\mu _{k,m}$ of two parameters for any integers $m\ge k\ge 1$. In this article, we will establish three kinds of asymptotic formulas related to $\mu _{k,m}$ for $m\ge k\ge 2$ in a unified elementary method. These formulas are related to the shifted convolution sums of Fourier coefficients of holomorphic cusp forms, Bergelson and Richter’s dynamical generalization of the prime number theorem, and the Titchmarsh divisor problem.