@inproceedings{21044, abstract = {Scalability is a crucial requirement for modern large-scale systems, enabling elasticity and ensuring responsiveness under varying load. While cloud systems have achieved scalable architectures, blockchain systems remain constrained by the need to over-provision validator machines to handle peak load. This leads to resource inefficiency, poor cost scaling, and limits on performance. To address these challenges, we introduce Pilotfish, the first scale-out transaction execution engine for blockchains. Pilotfish enables validators to scale horizontally by distributing transaction execution across multiple worker machines, allowing elasticity without compromising consistency or determinism. It integrates seamlessly with the lazy blockchain architecture, completing the missing piece of execution elasticity. To achieve this, Pilotfish tackles several key challenges: ensuring scalable and strongly consistent distributed transactions, handling partial crash recovery with lightweight replication, and maintaining concurrency with a novel versioned-queue scheduling algorithm. Our evaluation shows that Pilotfish scales linearly up to at least eight workers per validator for compute-bound workloads, while maintaining low latency. By solving scalable execution, Pilotfish brings blockchains closer to achieving end-to-end elasticity, unlocking new possibilities for efficient and adaptable blockchain systems.}, author = {Kniep, Quentin and Kokoris Kogias, Eleftherios and Sonnino, Alberto and Zablotchi, Igor and Zhang, Nuda}, booktitle = {29th International Conference on Financial Cryptography and Data Security}, isbn = {9783032070234}, issn = {1611-3349}, location = {Miyakojima, Japan}, pages = {287--306}, publisher = {Springer Nature}, title = {{Pilotfish: Distributed execution for scalable blockchains}}, doi = {10.1007/978-3-032-07024-1_17}, volume = {15751}, year = {2026}, } @article{21045, abstract = {The abundant population of little red dots (LRDs), compact objects with red UV to optical colors and broad Balmer lines at high redshift, is revealing new insights into the properties of early active galactic nuclei (AGN). Perhaps the most surprising features of this population are the presence of Balmer absorption and ubiquitous strong Balmer breaks. Recent models link these features to an active supermassive black hole (SMBH) cocooned in very dense gas (NH ∼ 1024 cm−2). We present a stringent test of such models using VLT/MUSE observations of A2744-45924, the most luminous LRD known to date (LHα ≈ 1044 erg s−1), located behind the Abell-2744 lensing cluster at z = 4.464 (μ = 1.8). We detect a moderately extended Lyα nebula (h ≈ 5.7 pkpc), spatially offset from the point-like Hα seen by JWST by ≈1.6 pkpc. The Lyα emission is narrow (FWHM = 270 ± 15 km s−1), and faint (Lyα = 0.07Hα) compared to Lyα nebulae typically observed around quasars of similar luminosity. We detect compact N IV]λ1486 emission, spatially aligned with Hα, and a spatial shift in the far-UV continuum matching the Lyα offset. We discuss that Hα and Lyα have distinct physical origins: Hα originates from the AGN, while Lyα is powered by star formation. In the environment of A2744-45924, we identified four extended Lyα halos (Δz < 0.02, Δr < 100 pkpc). Their Lyα luminosities match the expectations based on Hα emission, and show no evidence for radiation from A2744-45924 affecting its surroundings. The lack of strong, compact, and broad Lyα and the absence of a luminous extended halo, suggest that the UV AGN light is obscured by dense gas cloaking the SMBH with a covering factor close to unity.}, author = {Torralba Torregrosa, Alberto and Matthee, Jorryt J and Pezzulli, Gabriele and Urrutia, Tanya and Gronke, Max and Mascia, Sara and D’Eugenio, Francesco and Di Cesare, Claudia and Eilers, Anna Christina and Greene, Jenny E. and Iani, Edoardo and Ishikawa, Yuzo and Mackenzie, Ruari and Naidu, Rohan P. and Navarrete, Benjamín and Kotiwale, Gauri}, issn = {1432-0746}, journal = {Astronomy and Astrophysics}, publisher = {EDP Sciences}, title = {{A weak Ly α halo for an extremely bright little red dot. Indications of enshrouded supermassive black hole growth}}, doi = {10.1051/0004-6361/202555596}, volume = {705}, year = {2026}, } @unpublished{21051, abstract = {In this work, we introduce and study what we believe is an intriguing and, to the best of our knowledge, previously unknown connection between two areas in computational topology, topological data analysis (TDA) and knot theory. Given a function from a topological space to $\mathbb{R}$, TDA provides tools to simplify and study the importance of topological features: in particular, the $l^{th}$-dimensional persistence diagram encodes the $l$-homology in the sublevel set as the function value increases as a set of points in the plane. Given a continuous one-parameter family of such functions, we can combine the persistence diagrams into an object known as a vineyard, which track the evolution of points in the persistence diagram. If we further restrict that family of functions to be periodic, we identify the two ends of the vineyard, yielding a closed vineyard. This allows the study of monodromy, which in this context means that following the family of functions for a period permutes the set of points in a non-trivial way. In this work, given a link and value $l$, we construct a topological space and periodic family of functions such that the closed $l$-vineyard contains this link. This shows that vineyards are topologically as rich as one could possibly hope. Importantly, it has at least two immediate consequences: First, monodromy of any periodicity can occur in a $l$-vineyard, answering a variant of a question by [Arya et al 2024]. To exhibit this, we also reformulate monodromy in a more geometric way, which may be of interest in itself. Second, distinguishing vineyards is likely to be difficult given the known difficulty of knot and link recognition, which have strong connections to many NP-hard problems.}, author = { Chambers, Erin and Fillmore, Christopher D and Stephenson, Elizabeth R and Wintraecken, Mathijs}, booktitle = {arXiv}, title = {{Braiding vineyards}}, doi = {10.48550/ARXIV.2504.11203}, year = {2026}, } @inbook{21056, abstract = {In this work, we introduce and study what we believe is an intriguing, and, to the best of our knowledge, previously unknown connection between two fundamental areas in computational topology, namely topological data analysis (TDA) and knot theory. Given a function from a topological space to ℝ, TDA provides tools to simplify and study the importance of topological features: in particular, the 𝑙^𝑡⁢ℎ-dimensional persistence diagram encodes the topological changes (or 𝑙-homology) in the sublevel set as the function value increases into a set of points in the plane. Given a continuous one parameter family of such functions, we can combine the persistence diagrams into an object known as a vineyard, which tracks the evolution of points in the persistence diagram as the function changes. If we further restrict that family of functions to be periodic, we identify the two ends of the vineyard, yielding a closed vineyard. This allows the study of monodromy, which in this context means that following the family of functions for a period permutes the set of points in a non-trivial way. Recent work has studied monodromy in the directional persistent homology transform, demonstrating some interesting connections between an input shape and monodromy in the persistent homology transform for 0-dimensional homology embedded in ℝ^2. In this work, given a link and a value 𝑙, we construct a topological space (based on the given link) and periodic family of functions on this space (based on the Euclidean distance function), such that the closed 𝑙-vineyard contains this link. This shows that vineyards are topologically as rich as one could possibly hope, suggesting many future directions of work. Importantly, it has at least two immediate consequences we explicitly point out: 1. Monodromy of any periodicity can occur in a 𝑙-vineyard for any 𝑙. This answers a variant of a question by Arya and collaborators. To exhibit this as a consequence of our first main result we also reformulate monodromy in a more geometric way, which may be of interest in itself. 2. Topologically distinguishing closed vineyards is likely to be difficult (from a complexity theory as well as from a practical perspective) because of the difficulty of knot and link recognition, which have strong connections to many NP-hard problems.}, author = {Chambers, Erin W. and Fillmore, Christopher D and Stephenson, Elizabeth R and Wintraecken, Mathijs}, booktitle = {Proceedings of the 2026 Annual ACM-SIAM Symposium on Discrete Algorithms}, editor = {Green Larsen, Kasper and Saha, Barna}, pages = {6240--6263}, publisher = {Society for Industrial and Applied Mathematics}, title = {{Braiding Vineyards}}, doi = {10.1137/1.9781611978971.225}, year = {2026}, } @inproceedings{21113, abstract = {Causal discovery from i.i.d. observational data is known to be generally ill-posed. We demonstrate that if we have access to the distribution induced by a structural causal model, and additional data from (in the best case) only two environments that sufficiently differ in the noise statistics, the unique causal graph is identifiable. Notably, this is the first result in the literature that guarantees the entire causal graph recovery with a constant number of environments and arbitrary nonlinear mechanisms. Our only constraint is the Gaussianity of the noise terms; however, we propose potential ways to relax this requirement. Of interest on its own, we expand on the well-known duality between independent component analysis (ICA) and causal discovery; recent advancements have shown that nonlinear ICA can be solved from multiple environments, at least as many as the number of sources: we show that the same can be achieved for causal discovery while having access to much less auxiliary information.}, author = {Montagna, Francesco}, booktitle = {The 14th International Conference on Learning Representations}, location = {Rio de Janeiro, Brazil}, publisher = {OpenReview}, title = {{On the identifiability of causal graphs with multiple environments}}, year = {2026}, } @article{21115, abstract = {Quantifying cell morphology is central to understanding cellular regulation, fate, and heterogeneity, yet conventional image-based analyses often struggle with diverse or irregular shapes. We present a computational framework that uses topological data analysis to characterise and compare single-cell morphologies from fluorescence microscopy. Each cell is represented by its contour together with the position of its nucleus, from which we construct a filtration based on a radial distance function and derive a persistence diagram encoding the shape’s topological evolution. The similarity between two cells is quantified using the 2-Wasserstein distance between their diagrams, yielding a shape distance we call the PH distance. We apply this method to two representative experimental systems—primary human mesenchymal stem cells (hMSCs) and HeLa cells—and show that PH distances enable the detection of outliers in those systems, the identification of sub-populations, and the quantification of shape heterogeneity. We benchmark PH against three established contour-based distances (aspect ratio, Fourier descriptors, and elastic shape analysis) and show that PH offers better separation between cell types and greater robustness when clustering heterogeneous populations. Together, these results demonstrate that persistent-homology-based signatures provide a principled and sensitive approach for analysing cell morphology in settings where traditional geometric or image-based descriptors are insufficient.}, author = {Bleile, Yossi and Yadav, Pooja and Koehl, Patrice and Rehfeldt, Florian}, issn = {1553-7358}, journal = {PLoS Computational Biology}, publisher = {Public Library of Science}, title = {{Persistence diagrams as morphological signatures of cells: A method to measure and compare cells within a population}}, doi = {10.1371/journal.pcbi.1013890}, volume = {22}, year = {2026}, } @misc{21116, abstract = {Sex-chromosome systems are highly variable across animals, but how they transition from one to another is not well understood. Diptera have undergone multiple sex-chromosome turnovers and expansions while maintaining their general chromosomal content, which makes them an ideal clade to study such transitions. We analyzed more than 100 dipteran whole-genome assemblies and identified 4 new lineages that underwent sex-chromosome turnover (in addition to the 5 previously reported). We find that the majority of turnovers happened in the group Schizophora, which tend to have fewer genes on Muller element F (the chromosome homologous to the ancestral insect X chromosome) than lower dipterans, a factor previously hypothesized to facilitate turnover. Most derived X chromosomes have higher GC content than autosomes, consistent with a high prevalence of male achiasmy in Diptera. In addition, an excess of gene movement out of the X is detected for most of these new X chromosomes, and many of these moved genes have high testis expression in Drosophila, suggesting that out-of-X gene movement contributes to the long-term demasculinization of X chromosomes.}, author = {Layana Franco, Lorena Alexandra and Toups, Melissa A and Vicoso, Beatriz}, keywords = {Schizophora, sex chromosomes, sex-chromosome turnover, Diptera, genomic features, out-of-X movement.}, publisher = {Institute of Science and Technology Austria}, title = {{Research Data for "Causes and consequences of sex-chromosome turnovers in Diptera"}}, doi = {10.15479/AT-ISTA-21116}, year = {2026}, } @article{21132, abstract = {We unify the variational hypocoercivity framework established by D. Albritton, S. Armstrong, J.-C. Mourrat, and M. Novack [2], with the notion of second-order lifts of reversible diffusion processes, recently introduced by A. Eberle and the second author [30]. We give an abstract, yet fully constructive, presentation of the theory, so that it can be applied to a large class of linear kinetic equations. As this hypocoercivity technique does not twist the reference norm, we can recover accurate and sharp convergence rates in various models. Among those, adaptive Langevin dynamics (ALD) is discussed in full detail and we show that for near-quadratic potentials, with suitable choices of parameters, it is a near-optimal second-order lift of the overdamped Langevin dynamics. As a further consequence, we observe that the Generalised Langevin Equation (GLE) is also a second-order lift, as the standard (kinetic) Langevin dynamics are, of the overdamped Langevin dynamics. Then, convergence of (GLE) cannot exceed ballistic speed, i.e. the square root of the rate of the overdamped regime. We illustrate this phenomenon with explicit computations in a benchmark Gaussian case.}, author = {Brigati, Giovanni and Lörler, Francis and Wang, Lihan}, issn = {1937-5077}, journal = {Kinetic and Related Models}, pages = {34--55}, publisher = {American Institute of Mathematical Sciences}, title = {{Hypocoercivity meets lifts}}, doi = {10.3934/krm.2025020}, volume = {20}, year = {2026}, } @inproceedings{21133, abstract = {Data structures based on trees and tree traversals are ubiquitous in computer systems. Many low-level programs, including some implementations of critical systems like page tables and the web browser DOM, rely on generic tree-traversal functions that traverse tree nodes in a pre-determined order, applying a client-provided operation to each visited node. Developing a general approach to specifying and verifying such traversals is tricky since the client-provided per-node operation can be stateful and may potentially depend on or modify the structure of the tree being traversed. In this paper, we present a recipe for (semi-)automated verification of such generic, stateful tree traversals. Our recipe is (a) general: it applies to a range of tree traversals, in particular, pre-, post- and in-order depth-first traversals; (b) modular: parts of a traversal’s proof can be reused in verifying other similar traversals; (c) expressive: using the specification of a tree traversal, we can verify clients that use the traversal in a variety of different ways; and (d) automatable: many proof obligations can be discharged automatically. At the heart of our recipe is a novel use of tree zippers to represent a logical abstraction of the tree traversal state, and zipper transitions as an abstraction of traversal steps. We realize our recipe in the RefinedC framework in Rocq, which allows us to verify a number of different tree traversals and their clients written in C.}, author = {Elbeheiry, Laila and Sammler, Michael Joachim and Krebbers, Robbert and Dreyer, Derek and Garg, Deepak}, booktitle = {Proceedings of the 15th ACM SIGPLAN International Conference on Certified Programs and Proofs}, isbn = {9798400723414}, location = {Rennes, France}, pages = {339--352}, publisher = {Association for Computing Machinery}, title = {{A recipe for modular verification of generic tree traversals}}, doi = {10.1145/3779031.3779110}, year = {2026}, } @inproceedings{21134, abstract = {The Nakamoto consensus protocol underlying the Bitcoin blockchain uses proof of work as a voting mechanism. Honest miners who contribute hashing power towards securing the chain try to extend the longest chain they are aware of. Despite its simplicity, Nakamoto consensus achieves meaningful security guarantees assuming that at any point in time, a majority of the hashing power is controlled by honest parties. This also holds under “resource variability”, i.e., if the total hashing power varies greatly over time. Proofs of space (PoSpace) have been suggested as a more sustainable replacement for proofs of work. Unfortunately, no construction of a “longest-chain” blockchain based on PoSpace, that is secure under dynamic availability, is known. In this work, we prove that without additional assumptions no such protocol exists. We exactly quantify this impossibility result by proving a bound on the length of the fork required for double spending as a function of the adversarial capabilities. This bound holds for any chain selection rule, and we also show a chain selection rule (albeit a very strange one) that almost matches this bound. The Nakamoto consensus protocol underlying the Bitcoin blockchain uses proof of work as a voting mechanism. Honest miners who contribute hashing power towards securing the chain try to extend the longest chain they are aware of. Despite its simplicity, Nakamoto consensus achieves meaningful security guarantees assuming that at any point in time, a majority of the hashing power is controlled by honest parties. This also holds under “resource variability”, i.e., if the total hashing power varies greatly over time. Proofs of space (PoSpace) have been suggested as a more sustainable replacement for proofs of work. Unfortunately, no construction of a “longest-chain” blockchain based on PoSpace, that is secure under dynamic availability, is known. In this work, we prove that without additional assumptions no such protocol exists. We exactly quantify this impossibility result by proving a bound on the length of the fork required for double spending as a function of the adversarial capabilities. This bound holds for any chain selection rule, and we also show a chain selection rule (albeit a very strange one) that almost matches this bound. Concretely, we consider a security game in which the honest parties at any point control 0 > 1 times more space than the adversary. The adversary can change the honest space by a factor 1+- E with every block (dynamic availability), and “replotting” the space (which allows answering two challenges using the same space) takes as much time as p blocks. We prove that no matter what chain selection rule is used, in this game the adversary can create a fork of length o^2 . p/E that will be picked as the winner by the chain selection rule. We also provide an upper bound that matches the lower bound up to a factor o. There exists a chain selection rule (albeit a very strange one) which in the above game requires forks of length at least o . p/E Our results show the necessity of additional assumptions to create a secure PoSpace based longest-chain blockchain. The Chia network in addition to PoSpace uses a verifiable delay function. Our bounds show that an additional primitive like that is necessary.}, author = {Baig, Mirza Ahad and Pietrzak, Krzysztof Z}, booktitle = {29th International Conference on Financial Cryptography and Data Security}, isbn = {9783032070340}, issn = {1611-3349}, location = {Miyakojima, Japan}, pages = {127--142}, publisher = {Springer Nature}, title = {{On the (in)security of Proofs-of-space based longest-chain blockchains}}, doi = {10.1007/978-3-032-07035-7_8}, volume = {15752}, year = {2026}, } @inproceedings{21135, abstract = {Three-dimensional (3D) microscopy data is often anisotropic with significantly lower resolution (up to 8x) along the z axis than along the xy axes. Computationally generating plausible isotropic resolution from anisotropic imaging data would benefit the visual analysis of large-scale volumes. This paper proposes niiv, a self-supervised method for isotropic reconstruction of 3D microscopy data that can quickly produce images at arbitrary output resolutions. The representation embeds a learned latent code within a neural field that describes the implicit higher-resolution isotropic image region. We use an attention-guided latent interpolation approach, which allows flexible information exchange over a local latent neighborhood. Under isotropic volume assumptions, we self-supervise this representation on low-/high-resolution lateral image pairs to reconstruct an isotropic volume from low-resolution axial images. We evaluate our method on simulated and real anisotropic electron (EM) and light microscopy (LM) data. Compared to diffusion-based baselines, niiv shows improved reconstruction quality (+1 dB PSNR) and is over three orders of magnitude faster (1,000x) to infer. Specifically, niiv reconstructs a 128^3 voxel volume in 2/10th of a second, renderable at varying (continuous) high resolutions for display. Our code is available at https://github.com/jakobtroidl/niiv-miccai.}, author = {Troidl, Jakob and Liang, Yiqing and Beyer, Johanna and Tavakoli, Mojtaba and Danzl, Johann G and Hadwiger, Markus and Pfister, Hanspeter and Tompkin, James}, booktitle = {1st International Workshop on Efficient Medical Artificial Intelligence}, isbn = {9783032139603}, issn = {1611-3349}, location = {Daejeon, South Korea}, pages = {257--267}, publisher = {Springer Nature}, title = {{niiv: Interactive Self-supervised Neural Implicit Isotropic Volume Reconstruction}}, doi = {10.1007/978-3-032-13961-0_26}, volume = {16318}, year = {2026}, } @misc{21137, author = {Naik, Suyash}, publisher = {Institute of Science and Technology Austria}, title = {{Data associated with Keratins coordinate tissue spreading }}, doi = {10.15479/AT-ISTA-21137}, year = {2026}, } @inproceedings{21140, abstract = {We consider several problems related to packing forests in graphs. The first one is to find k edge-disjoint forests in a directed graph G of maximal size such that the indegree of each vertex in these forests is at most k. We describe a min-max characterization for this problem and show that it can be solved in almost linear time for fixed k, extending the algorithm of [Gabow, 1995]. Specifically, the complexity is O(kδm log n), where n, m are the number of vertices and edges in G respectively, and δ = max{1, k − kG}, where kG is the edge connectivity of the graph. Using our solution to this problem, we improve complexities for two existing applications:(1) k-forest problem: find k forests in an undirected graph G maximizing the number of edges in their union. We show how to solve this problem in O(k3 min{kn, m} log2 n + k · MAXFLOW(m, m) log n) time, breaking the Ok(n3/2) complexity barrier of previously known approaches.(2) Directed edge-connectivity augmentation problem: find a smallest set of directed edges whose addition to the given directed graph makes it strongly k-connected. We improve the deterministic complexity for this problem from O(kδ(m + δn) log n) [Gabow, STOC 1994] to O(kδm log n). A similar approach with the same complexity also works for the undirected version of the problem.}, author = {Arkhipov, Pavel and Kolmogorov, Vladimir}, booktitle = {Proceedings of the 2026 Annual ACM-SIAM Symposium on Discrete Algorithms}, location = {Vancouver, Canada}, pages = {4023--4042}, publisher = {Society for Industrial and Applied Mathematics}, title = {{Faster algorithms for packing forests in graphs and related problems}}, doi = {10.1137/1.9781611978971.148}, year = {2026}, } @article{21149, abstract = {We present a general theoretical framework for helical dichroism (HD), establishing an explicit link between chiral resolution and orbital angular momentum (OAM) exchange in light–matter interaction. Tracing microscopic mechanisms of the OAM transfer, we derive rotational selection rules, which establish that HD emerges only from the spin–orbit coupling of light, even for beams without the far-field OAM. Our findings refine the conditions for observing HD, provide a tool to re-examine the outcome of prior experiments, and guide future designs for chiral sensing with structured light.}, author = {Hrast, Mateja and Koutentakis, Georgios and Maslov, Mikhail and Lemeshko, Mikhail}, issn = {1079-7114}, journal = {Physical Review Letters}, number = {5}, publisher = {American Physical Society}, title = {{Bottom-up analysis of rovibrational helical dichroism}}, doi = {10.1103/fkf1-1jml}, volume = {136}, year = {2026}, } @article{21158, abstract = {Vernalization-regulated flowering is vital for wheat yield and geographical distribution, and the diversity of flowering time genes is essential for the breeding of climate-resilient varieties. Sugars have long been recognized in regulating flowering; however, the intrinsic connection between carbohydrate metabolism and vernalization response remains largely unexplored. Here, we identify a fructose 1,6-bisphosphate aldolase (FBA) encoding gene, HtL1/FBA10, as a modulator of heading time variation based on a genome-wide association study utilizing wheat core germplasm collections. Evolutionary analysis shows a decrease in the proportion of haplotype-2 of HtL1, which is linked to delayed flowering, in Chinese and American wheat varieties compared to landraces. Vernalization reduces HtL1/FBA10 phosphorylation levels and increases its O-GlcNAcylation, which in turn enhances its enzymatic activity and facilitates VERNALIZATION 1 (VRN1) transcription by regulating histone acetylation at the VRN1 locus. Our findings provide mechanistic insights into the interplay between glucose metabolism and the epigenetic regulation of vernalization in winter wheat.}, author = {Yang, Pengfang and Liu, Yangyang and Dong, Qi and Miao, Yuting and Zhang, Jianlong and Xu, Shujuan and Zhao, Hong and Niu, Yuda and Zhang, Xueyong and Xu, Yunyuan and Guo, Zifeng and Xing, Lijing and Chong, Kang}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{O-GlcNAc and phosphorylation modifications on HtL1/FBA10 regulate wheat vernalization for flowering}}, doi = {10.1038/s41467-025-67734-0}, volume = {17}, year = {2026}, } @article{21159, abstract = {One of the foundational theorems of extremal graph theory is Dirac’s theorem, which says that if an n-vertex graph G has minimum degree at least n/2, then G has a Hamilton cycle, and therefore a perfect matching (if n is even). Later work by Sárközy, Selkow and Szemerédi showed that in fact Dirac graphs have many Hamilton cycles and perfect matchings, culminating in a result of Cuckler and Kahn that gives a precise description of the numbers of Hamilton cycles and perfect matchings in a Dirac graph G (in terms of an entropy-like parameter of G). In this paper we extend Cuckler and Kahn’s result to perfect matchings in hypergraphs. For positive integers d < k, and for n divisible by k, let md (k, n) be the minimum d-degree that ensures the existence of a perfect matching in an n-vertex k-uniform hypergraph. In general, it is an open question to determine (even asymptotically) the values of md (k, n), but we are nonetheless able to prove an analogue of the Cuckler–Kahn theorem, showing that if an n-vertex k-uniform hypergraph G has minimum d-degree at least (1+γ )md (k, n) (for any constantγ > 0), then the number of perfect matchings in G is controlled by an entropy-like parameter of G. This strengthens cruder estimates arising from work of Kang–Kelly–Kühn–Osthus–Pfenninger and Pham–Sah–Sawhney–Simkin.}, author = {Kwan, Matthew Alan and Safavi Hemami, Roodabeh and Wang, Yiting}, issn = {1439-6912}, journal = {Combinatorica}, publisher = {Springer Nature}, title = {{Counting perfect matchings in Dirac hypergraphs}}, doi = {10.1007/s00493-025-00194-8}, volume = {46}, year = {2026}, } @article{21160, abstract = {Context. AM Canum Venaticorum (AM CVn) stars are ultra-compact binary systems composed of a white dwarf primary accreting from a hydrogen-deficient donor. They play a crucial role in astrophysics as potential progenitors of Type Ia supernovae and as laboratories for gravitational wave studies. However, their formation and evolutionary history remain incomplete. Three formation channels have been discussed in the literature: the white dwarf, He-star, and cataclysmic variable channels. Aims. The chemical composition of the accretor atmosphere reflects the material transferred from the donor. In this work we took the first accurate measurements of the fundamental parameters of the accreting white dwarf in ZTF J225237.05−051917.4, including the abundances of key elements such as carbon, nitrogen, and silicon, by analysing ultraviolet spectra obtained with the Hubble Space Telescope (HST). These measurements provide new insight into the evolutionary history of the system and, together with existing optical observations, establish it as a benchmark to develop our pipeline, paving the way for its application to a larger sample of AM CVn systems. Methods. We determined the binary parameters through photometric analysis and constrained the atmospheric parameters of the white dwarf accretor, including its effective temperature, surface gravity, and chemical abundances, by fitting the HST ultraviolet spectrum with synthetic spectral models. We then inferred the system’s formation channel by comparing the results with theoretical evolutionary models. Results. According to our measurements, the accretor’s effective temperature (Teff) is 23 300 ± 600 K and the surface gravity (log g) is 8.4 ± 0.3, which imply an accretor mass (MWD) of 0.86 ± 0.16 M⊙. We find a high nitrogen-to-carbon abundance ratio by mass of > 153. Conclusions. The accretor is significantly hotter than previous estimates based on simplified blackbody fits to the spectral energy distribution, underscoring the importance of detailed spectral modelling for accurately determining system parameters. Our results show that ultraviolet spectroscopy is well suited to constraining the formation channels of AM CVn systems. Of the three proposed formation channels, the He-star channel can be excluded given the high nitrogen-to-carbon ratio. Our results are consistent with both the white dwarf and cataclysmic variable channels.}, author = {Yu, W. and Pala, A. F. and Kupfer, T. and Gänsicke, B. T. and Koester, D. and Belloni, D. and Wong, T. L.S. and Schreiber, M. R. and van Roestel, Joannes C and Brown, A. J. and Waagen, E. O. and González-Carballo, J. L. and Bednarz, S. and Bernacki, K. and De Martino, D. and Fernández Mañanes, E. and González Farfán, R. and Green, M. J. and Groot, P. J. and Hambsch, F. J. and Knigge, C. and Martin-Velasco, J. L. and Morales-Aimar, M. and Myers, G. and Naves Nogues, R. and Poggiani, R. and Popowicz, A. and Ramsay, G. and Reina-Lorenz, E. and Rodríguez-Gil, P. and Salto-González, J. L. and Sion, E. M. and Steeghs, D. and Szkody, P. and Toloza, O. and Tovmassian, G.}, issn = {1432-0746}, journal = {Astronomy and Astrophysics}, publisher = {EDP Sciences}, title = {{The evolutionary history of ultra-compact accreting binaries: I. Chemical abundances and the formation channel of the eclipsing AM CVn system ZTF J225237.05-051917.4 from HST spectroscopy}}, doi = {10.1051/0004-6361/202557568}, volume = {706}, year = {2026}, } @article{21161, abstract = {In many species, sex-biased expression is widespread and thought to contribute to sexual dimorphism. While bulk RNA-sequencing has been instrumental in identifying strongly sex-biased genes, it lacks resolution to assess variation across cell-types and tissue compartments. Using single-nucleus expression data from the Fly Cell Atlas, we investigate sex differences in adult Drosophila melanogaster. We find that differences in cell-type composition between the sexes are not a major source of sex-bias, as for the vast majority of genes, the degree of sex-bias is similar regardless of whether sex differences in cell-type composition are controlled for or not. Our analysis confirms a deficit of X-linked male-biased genes in the body’s somatic tissues that is widespread across cell-types. We also find the excess of X-linked female-biased genes to be associated with nervous system cells in the head but with epithelial cells in the body’s somatic tissues, showing that single-nucleus data crucially resolves sex-bias at the cell-type level. We investigate dosage compensation (DC) across 15 tissues and 17 cell-types. We observe that it varies throughout the body. Surprisingly, we observe a lack of DC in a cluster of main cells within the male accessory glands. This result highlights the importance of understanding context-dependent DC.}, author = {De Castro Barbosa Rodrigues Barata, Carolina and Vicoso, Beatriz}, issn = {1471-2954}, journal = {Proceedings of the Royal Society B Biological Sciences}, number = {2063}, publisher = {Royal Society of London}, title = {{Single-nucleus resolution of sex-biased expression and dosage compensation in Drosophila melanogaster}}, doi = {10.1098/rspb.2025.2471}, volume = {293}, year = {2026}, } @article{21164, abstract = {Global emission inventories often fail to capture the complexities of vehicular pollution in regions with unique fuel mixes, such as Brazil’s extensive biofuel use, leading to significant uncertainties in atmospheric modeling. This study presents a century-long (1960–2100) bottom-up vehicular emission inventory for Brazil, leveraging locally derived emission factors. Our estimates reveal substantial discrepancies in magnitude, timing, and speciation of non-CO2 pollutants (CO, NMHC, PM2.5) compared to leading global inventories (EDGAR, CEDS, CAMS), highlighting critical inaccuracies in widely used data sets. More critically, future projections under Shared Socioeconomic Pathways (SSPs) uncover a novel positive feedback mechanism: rising temperatures significantly enhance vehicular evaporative nonmethane hydrocarbon (NMHC) emissions. This temperature-dependent increase and subsequent NMHC oxidation to CO2 suggest an overlooked pathway that could amplify climate warming and air pollution globally, particularly after a breakpoint around 2050 (p < 0.05). While historical emissions peaked in the 1990s–2000s, nonexhaust PM becomes increasingly important. Air quality simulations using our inventory in the MUSICA model show good regional PM2.5 agreement but highlight challenges in resolving local primary pollutant peaks. This comprehensive inventory provides crucial data for Brazil and uncovers globally relevant climate–chemistry interactions, urging a re-evaluation of regional specificities in global emission assessments.}, author = {Ibarra-Espinosa, Sergio and Dias de Freitas, Edmilson and Gaubert, Benjamin and Lichtig, Pablo and Ropkins, Karl and da Silva, Iara and Martins Pereira, Guilherme and Schuch, Daniel and Nascimento, Janaina and Hoinaski, Leonardo and Martins, Leila Droprinchinski and Gavidia-Calderón, Mario and Vara-Vela, Angel and Toledo de Almeida Albuquerque, Taciana and Ynoue, Rita Yuri and Diez, Sebastian and Mera, Zamir and Casallas Garcia, Alejandro and Vallejo, Fidel and Diaz, Valeria and Pedruzzi, Rizzieri and Abrutzky, Rosana and Franco, Marco A. and Huneeus, Nicolas and Jorquera, Hector and Belalcázar-Cerón, Luis Carlos and Rojas, Néstor Y. and de Fatima Andrade, Maria and Emmons, Louisa and Brasseur, Guy}, issn = {1520-5851}, journal = {Environmental Science & Technology}, publisher = {American Chemical Society}, title = {{A century of vehicular emissions in Brazil: Unveiling the impacts of unique fuel mix on air quality}}, doi = {10.1021/acs.est.5c08400}, year = {2026}, } @misc{21174, abstract = {UTe2 exhibits the remarkable phenomenon of re-entrant superconductivity, whereby the zero-resistance state reappears above 40 tesla after being suppressed with a field of around 10 tesla. One potential pairing mechanism, invoked in the related re-entrant superconductors UCoGe and URhGe, involves transverse fluctuations of a ferromagnetic order parameter. However, the requisite ferromagnetic order - present in both UCoGe and URhGe - is absent in UTe2, and magnetization measurements show no sign of strong fluctuations. Here, we measure the magnetotropic susceptibility of UTe2 across two field-angle planes. This quantity is sensitive to the magnetic susceptibility in a direction transverse to the applied magnetic field - a quantity that is not accessed in conventional magnetization measurements. We observe a very large decrease in the magnetotropic susceptibility over a broad range of field orientations, indicating a large increase in the transverse magnetic susceptibility. The three superconducting phases of UTe2, including the high-field re-entrant phase, surround this region of enhanced susceptibility in the field-angle phase diagram. The strongest transverse susceptibility is found near the critical end point of the high-field metamagnetic transition, suggesting that quantum critical fluctuations of a field-induced magnetic order parameter may be responsible for the large transverse susceptibility, and may provide a pairing mechanism for field-induced superconductivity in UTe2.}, author = {Modic, Kimberly A}, keywords = {transverse magnetic susceptibility, magnetotropic, superconductivity, magnetic fluctuations}, publisher = {Institute of Science and Technology Austria}, title = {{Research data for "Giant transverse magnetic fluctuations at the edge of re-entrant superconductivity in UTe2"}}, doi = {10.15479/AT-ISTA-21174}, year = {2026}, }