@article{19673, abstract = {We show that almost all primes p =\= ± 4 mod9 are sums of three cubes, assuming a conjecture due to Hooley, Manin, et al. on cubic fourfolds. This conjecture is approachable under standard statistical hypotheses on geometric families of L-functions.}, author = {Wang, Victor}, issn = {2998-4114}, journal = {Journal of the Association for Mathematical Research}, number = {1}, pages = {1--26}, publisher = {Association for Mathematical Research}, title = {{Prime Hasse principles via diophantine second moments}}, doi = {10.56994/JAMR.003.001.001}, volume = {3}, year = {2025}, } @unpublished{19674, abstract = {When examined through the lens of their residual streams, a puzzling property emerges in transformer networks: residual contributions (e.g., attention heads) sometimes specialize in specific tasks or input attributes. In this paper, we analyze this phenomenon in vision transformers, focusing on the spectral geometry of residuals, and explore its implications for modality alignment in vision-language models. First, we link it to the intrinsically low-dimensional structure of visual head representations, zooming into their principal components and showing that they encode specialized roles across a wide variety of input data distributions. Then, we analyze the effect of head specialization in multimodal models, focusing on how improved alignment between text and specialized heads impacts zero-shot classification performance. This specialization-performance link consistently holds across diverse pre-training data, network sizes, and objectives, demonstrating a powerful new mechanism for boosting zero-shot classification through targeted alignment. Ultimately, we translate these insights into actionable terms by introducing ResiDual, a technique for spectral alignment of the residual stream. Much like panning for gold, it lets the noise from irrelevant unit principal components (i.e., attributes) wash away to amplify task-relevant ones. Remarkably, this dual perspective on modality alignment yields fine-tuning level performance on different data distributions while modelling an extremely interpretable and parameter-efficient transformation, as we extensively show on 70 pre-trained network-dataset combinations (7 models, 10 datasets).}, author = {Basile, Lorenzo and Maiorca, Valentino and Bortolussi, Luca and Rodolà, Emanuele and Locatello, Francesco}, booktitle = {arXiv}, title = {{ResiDual transformer alignment with spectral decomposition}}, doi = {10.48550/arXiv.2411.00246}, year = {2025}, } @phdthesis{19684, abstract = {The overarching goal of this thesis is to break down the complexity of turbulent flows in terms of enumerable, coherent structures and patterns. In a five-paper series, we adopt a variety of perspectives and techniques to relate the properties of systems of increasing complexity to their underlying coherent structures. Initially, we take a dynamical systems point of view, seeing turbulent flow as a chaotic trajectory bouncing between exact unstable solutions of the underlying equations of motion. Using persistent homology, the main tool of topological data analysis capturing the persistence across scales of topological features in a point cloud, we introduce a method that quantifies visits of turbulent trajectories to unstable time-periodic solutions, also called periodic orbits. We demonstrate this method first in the Rössler and Kuramoto–Sivashinsky systems. Using this method in 3D Kolmogorov flow, we extract a Markov chain from turbulent data, where each node corresponds to the neighbourhood of a periodic orbit. The invariant distribution of this Markov chain reproduces expectation values on turbulent data when it is used to weight averages on the respective periodic orbits. In more realistic, wall-bounded settings, such as plane-Couette flow (pcf) driven by the relative motion of the walls, or plane-Poiseuille flow (ppf) driven by a pressure gradient, finding exact solutions is difficult. We use dynamic mode decomposition (DMD), a dimensionality reduction method for sequential data, to identify and approximate low-dimensional dynamics without knowing any exact solutions. Most spatially-extended systems are equivariant under translations, and in such cases spatial drifts dominate DMD, hindering its use in the search for and modelling of low-dimensional dynamics. We augment DMD with a symmetry reduction method trained on turbulent data to stop it from seeing translations as a feature, improving its ability to extract dynamical information in translation-equivariant systems. We find segments of turbulent trajectories that linearize well with their symmetry-reduced DMD spectra, akin to dynamics near exact solutions. Searching for harmonics in the spectra gives leads for periodic orbits with spatial drifts, one of which converges to a new solution. In larger domains, turbulence can localize and coexist with surrounding laminar flow. Our preceding approaches are global, taking all of a domain into account at once, and cannot readily treat each localized patch individually. Working first in a minimal oblique domain that can host a single 1D-localized turbulent patch, we find that turbulence in ppf is connected to a stable periodic orbit at a flow velocity much lower than when turbulence is first onset. We show that, well in advance of sustained turbulence, chaos sets in explosively, and for long time horizons, time series are consistent with that of a random process. Finally, in much larger domains, we study and compare 2D-localized turbulence that appears as large-scale inclined structures, called stripes, in ppf and pcf. While appearing similar, we find that stripes in these two settings differ significantly in terms of how they sustain themselves, and in higher velocities, how they proliferate.}, author = {Yalniz, Gökhan}, issn = {2663-337X}, pages = {155}, publisher = {Institute of Science and Technology Austria}, title = {{Transition to turbulence : Data-, solution-, and pattern-driven approaches}}, doi = {10.15479/AT-ISTA-19684}, year = {2025}, } @misc{19696, author = {Tatman, Benjamin}, publisher = {Institute of Science and Technology Austria}, title = {{Dataset for "Bumps on the Road: The Way to Clean Relaxation Dispersion in the Solid State"}}, doi = {10.15479/AT-ISTA-19696}, year = {2025}, } @article{19699, abstract = {We demonstrate that gas disks around binary systems might deliver gas to the binary components only when the circumbinary disk is relatively warm. We present new grid-based hydrodynamics simulations, performed with the binary on the grid and a locally isothermal equation of state, in which the binary is seen to functionally "stop accreting" if the orbital Mach number in the disk exceeds a threshold value of about 40. Above this threshold, the disk continues to extract angular momentum from the binary orbit, but it delivers very little mass to the black holes and instead piles up mass in a ring surrounding the binary. This ring will eventually become viscously relaxed and deliver mass to the binary at the large-scale inflow rate. However, we show that the timescale for such relaxation can far exceed the implied binary lifetime. We demonstrate that the ability of a binary–disk system to equilibrate is dependent on the efficiency at which accretion streams deposit mass onto the binary, which, in turn is highly sensitive to the thermodynamic conditions of the inner disk. If disks around massive black hole binaries do operate in such nonaccreting regimes, it suggests these systems may be dimmer than their single black hole counterparts but could exhibit dramatic rebrightening after the black holes inspiral and merge. This dimming begins in the UV/optical and could completely choke high-energy emission, such that these systems would likely be intrinsically X-ray weak with reddened continua, potentially resembling the spectra of "little red dots" recently identified in JWST observations.}, author = {Tiede, Christopher and Zrake, Jonathan and Macfadyen, Andrew and Haiman, Zoltán}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{Suppressed accretion onto massive black hole binaries surrounded by thin disks}}, doi = {10.3847/1538-4357/adc727}, volume = {984}, year = {2025}, } @article{19700, abstract = {The JWST discovery of "little red dots" (LRDs) is reshaping our picture of the early Universe, yet the physical mechanisms driving their compact size and UV-optical colors remain elusive. Here, we report an unusually bright LRD (zspec = 3.1) observed as part of the RUBIES program. This LRD exhibits broad emission lines (FWHM ∼ 4000 km s−1), a blue UV continuum, a clear Balmer break, and a red continuum sampled out to rest-frame 4 μm with MIRI. We develop a new joint galaxy and active galactic nucleus (AGN) model within the Prospector Bayesian inference framework and perform spectrophotometric modeling using NIRCam, MIRI, and NIRSpec/Prism observations. Our fiducial model reveals a M* ∼ 109 M⊙ galaxy alongside a dust-reddened AGN driving the optical emission. Explaining the rest-frame optical color as a reddened AGN requires AV ≳ 3, suggesting that a great majority of the accretion disk energy is reradiated as dust emission. Yet, despite clear AGN signatures, we find a surprising lack of hot torus emission, which implies that either the dust emission in this object must be cold, or the red continuum must instead be driven by a massive, evolved stellar population of the host galaxy—seemingly inconsistent with the high-EW broad lines (Hα rest-frame EW ∼ 800 Å). The widths and luminosities of Pa-β, Pa-δ, Pa-γ, and Hα imply a modest black hole mass of MBH ∼ 108 M⊙. Additionally, we identify a narrow blueshifted He i λ 1.083 μm absorption feature in NIRSpec/G395M spectra, signaling an ionized outflow with kinetic energy up to ∼1% the luminosity of the AGN. The low redshift of RUBIES-BLAGN-1, combined with the depth and richness of the JWST imaging and spectroscopic observations, provides a unique opportunity to build a physical model for these so-far mysterious LRDs, which may prove to be a crucial phase in the early formation of massive galaxies and their supermassive black holes.}, author = {Wang, Bingjie and De Graaff, Anna and Davies, Rebecca L. and Greene, Jenny E. and Leja, Joel and Brammer, Gabriel B. and Goulding, Andy D. and Miller, Tim B. and Suess, Katherine A. and Weibel, Andrea and Williams, Christina C. and Bezanson, Rachel and Boogaard, Leindert A. and Cleri, Nikko J. and Hirschmann, Michaela and Katz, Harley and Labbé, Ivo and Maseda, Michael V. and Matthee, Jorryt J and Mcconachie, Ian and Naidu, Rohan P. and Oesch, Pascal A. and Rix, Hans Walter and Setton, David J. and Whitaker, Katherine E.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{RUBIES: JWST/NIRSpec confirmation of an infrared-luminous, broad-line Little Red Dot with an ionized outflow}}, doi = {10.3847/1538-4357/adc1ca}, volume = {984}, year = {2025}, } @article{19701, abstract = {Living systems are characterized by controlled flows of matter, energy, and information. While the biophysics community has productively engaged with the first two, addressing information flows has been more challenging, with some scattered success in evolutionary theory and a more coherent track record in neuroscience. Nevertheless, interdisciplinary work of the past two decades at the interface of biophysics, quantitative biology, and engineering has led to an emerging mathematical language for describing information flows at the molecular scale. This is where the central processes of life unfold: from detection and transduction of environmental signals to the readout or copying of genetic information and the triggering of adaptive cellular responses. Such processes are coordinated by complex biochemical reaction networks that operate at room temperature, are out of equilibrium, and use low copy numbers of diverse molecular species with limited interaction specificity. Here we review how flows of information through biochemical networks can be formalized using information-theoretic quantities, quantified from data, and computed within various modeling frameworks. Optimization of information flows is presented as a candidate design principle that navigates the relevant time, energy, crosstalk, and metabolic constraints to predict reliable cellular signaling and gene regulation architectures built of individually noisy components.}, author = {Tkačik, Gašper and Wolde, Pieter Rein Ten}, issn = {1936-1238}, journal = {Annual review of biophysics}, pages = {249--274}, publisher = {Annual Reviews}, title = {{Information processing in biochemical networks}}, doi = {10.1146/annurev-biophys-060524-102720}, volume = {54}, year = {2025}, } @article{19703, abstract = {An enlarged brain underlies the complex central nervous system of vertebrates. The dramatic expansion of the brain that diverges its shape from the spinal cord follows neural tube closure during embryonic development. Here, we show that this differential deformation is encoded by a pre-pattern of tissue material properties in chicken embryos. Using magnetic droplets and atomic force microscopy, we demonstrate that the dorsal hindbrain is more fluid than the dorsal spinal cord, resulting in a thinning versus a resisting response to increasing lumen pressure, respectively. The dorsal hindbrain exhibits reduced apical actin and a disorganized laminin matrix consistent with tissue fluidization. Blocking the activity of neural-crest-associated matrix metalloproteinases inhibits hindbrain expansion. Transplanting dorsal hindbrain cells to the spinal cord can locally create an expanded brain-like morphology in some cases. Our findings raise questions in vertebrate head evolution and suggest a general role of mechanical pre-patterning in sculpting epithelial tubes.}, author = {Mclaren, Susannah B.P. and Xue, Shi-lei and Ding, Siyuan and Winkel, Alexander K. and Baldwin, Oscar and Dwarakacherla, Shreya and Franze, Kristian and Hannezo, Edouard B and Xiong, Fengzhu}, issn = {1878-1551}, journal = {Developmental Cell}, number = {17}, pages = {2237--2247.e4}, publisher = {Elsevier}, title = {{Differential tissue deformability underlies fluid pressure-driven shape divergence of the avian embryonic brain and spinal cord}}, doi = {10.1016/j.devcel.2025.04.010}, volume = {60}, year = {2025}, } @article{19704, abstract = {The information-processing capability of the brain’s cellular network depends on the physical wiring pattern between neurons and their molecular and functional characteristics. Mapping neurons and resolving their individual synaptic connections can be achieved by volumetric imaging at nanoscale resolution1,2 with dense cellular labelling. Light microscopy is uniquely positioned to visualize specific molecules, but dense, synapse-level circuit reconstruction by light microscopy has been out of reach, owing to limitations in resolution, contrast and volumetric imaging capability. Here we describe light-microscopy-based connectomics (LICONN). We integrated specifically engineered hydrogel embedding and expansion with comprehensive deep-learning-based segmentation and analysis of connectivity, thereby directly incorporating molecular information into synapse-level reconstructions of brain tissue. LICONN will allow synapse-level phenotyping of brain tissue in biological experiments in a readily adoptable manner.}, author = {Tavakoli, Mojtaba and Lyudchik, Julia and Januszewski, Michał and Vistunou, Vitali and Agudelo Duenas, Nathalie and Vorlaufer, Jakob and Sommer, Christoph M and Kreuzinger, Caroline and Oliveira, Bárbara and Cenameri, Alban and Novarino, Gaia and Jain, Viren and Danzl, Johann G}, issn = {1476-4687}, journal = {Nature}, pages = {398--410}, publisher = {Springer Nature}, title = {{Light-microscopy-based connectomic reconstruction of mammalian brain tissue}}, doi = {10.1038/s41586-025-08985-1}, volume = {642}, year = {2025}, } @article{19705, abstract = {A maximal realization of the two-dimensional Pauli operator, subject to Aharonov–Bohm magnetic field, is investigated. Contrary to the case of the Pauli operator with regular magnetic potentials, it is shown that both components of the Pauli operator are critical. Asymptotics of the weakly coupled eigenvalues, generated by electric (not necessarily self-adjoint) perturbations, are derived.}, author = {Fialova, Marie and Krejčiřík, David}, issn = {1793-6659}, journal = {Reviews in Mathematical Physics}, number = {6}, publisher = {World Scientific Publishing}, title = {{Virtual bound states of the Pauli operator with an Aharonov–Bohm potential}}, doi = {10.1142/S0129055X25500114}, volume = {37}, year = {2025}, } @inproceedings{19712, abstract = {We study recent algebraic attacks (Briaud-Øygarden EC’23) on the Regular Syndrome Decoding (RSD) problem and the assumptions underlying the correctness of their attacks’ complexity estimates. By relating these assumptions to interesting algebraic-combinatorial problems, we prove that they do not hold in full generality. However, we show that they are (asymptotically) true for most parameter sets, supporting the soundness of algebraic attacks on RSD. Further, we prove—without any heuristics or assumptions—that RSD can be broken in polynomial time whenever the number of error blocks times the square of the size of error blocks is larger than 2 times the square of the dimension of the code. Additionally, we use our methodology to attack a variant of the Learning With Errors problem where each error term lies in a fixed set of constant size. We prove that this problem can be broken in polynomial time, given a sufficient number of samples. This result improves on the seminal work by Arora and Ge (ICALP’11), as the attack’s time complexity is independent of the LWE modulus.}, author = {Cueto Noval, Miguel and Merz, Simon-Philipp and Stählin, Patrick and Ünal, Akin}, booktitle = {44th Annual International Conference on the Theory and Applications of Cryptographic Techniques}, isbn = {9783031910944}, issn = {1611-3349}, location = {Madrid, Spain}, pages = {385--415}, publisher = {Springer Nature}, title = {{On the soundness of algebraic attacks against code-based assumptions}}, doi = {10.1007/978-3-031-91095-1_14}, volume = {15606}, year = {2025}, } @article{19713, abstract = {Distributed optimization is the standard way of speeding up machine learning training, and most of the research in the area focuses on distributed first-order, gradient-based methods. Yet, there are settings where some computationally-bounded nodes may not be able to implement first-order, gradient-based optimization, while they could still contribute to joint optimization tasks. In this paper, we initiate the study of hybrid decentralized optimization, studying settings where nodes with zeroth-order and first-order optimization capabilities co-exist in a distributed system, and attempt to jointly solve an optimization task over some data distribution. We essentially show that, under reasonable parameter settings, such a system can not only withstand noisier zeroth-order agents but can even benefit from integrating such agents into the optimization process, rather than ignoring their information. At the core of our approach is a new analysis of distributed optimization with noisy and possibly-biased gradient estimators, which may be of independent interest. Our results hold for both convex and non-convex objectives. Experimental results on standard optimization tasks confirm our analysis, showing that hybrid first-zeroth order optimization can be practical, even when training deep neural networks.}, author = {Talaei, Shayan and Ansaripour, Matin and Nadiradze, Giorgi and Alistarh, Dan-Adrian}, issn = {2374-3468}, journal = {Proceedings of the 39th AAAI Conference on Artificial Intelligence}, number = {19}, pages = {20778--20786}, publisher = {Association for the Advancement of Artificial Intelligence}, title = {{Hybrid decentralized optimization: Leveraging both first- and zeroth-order optimizers for faster convergence}}, doi = {10.1609/aaai.v39i19.34290}, volume = {39}, year = {2025}, } @unpublished{19717, abstract = {Radial glial progenitors (RGPs) generate all projection neurons (PNs) in the cerebral cortex through incompletely understood processes. Herein, we combine Mosaic Analysis with Double Markers (MADM)-based clonal analysis at embryonic days 12.5 and 13.5 with early postnatal callosal tracing to reveal a lineage progression that challenges the inside-outside model of cortical development and the conventional view of an invariable sequence of asymmetric neurogenic divisions. Our data demonstrate that early multipotent RGPs generate all extra-telencephalic (ET) and intra-telencephalic (IT) PNs across all layers through parallel sublineages and the random specification, during the earliest neurogenic divisions, of fate-restricted daughter RGPs. While the neuronal production of the parental multipotent RGPs consists of small ET-PN or IT-PN outputs, fate-restricted RGPs produce larger translaminar outputs spanning deep and upper layers of only IT-PNs, the predominant mammalian PN subtype. We further show that the emergence of IT-PN fate-restricted RGPs also leads to quantitatively and temporally stereotyped neurogenesis population-wise.}, author = {Varela-Martínez, I and Villalba Requena, Ana and Garcia-Marqués, J. and Hippenmeyer, Simon and Nieto, M.}, booktitle = {bioRxiv}, title = {{Early emergence of projection-subtype fate-restricted radial glial progenitors orchestrates neocortical neurogenesis}}, doi = {10.1101/2025.05.07.652665}, year = {2025}, } @article{19718, abstract = {The cerebral cortex is arguably the most complex organ in humans. The cortical architecture is characterized by a remarkable diversity of neuronal and glial cell types that make up its neuronal circuits. Following a precise temporally ordered program, radial glia progenitor (RGP) cells generate all cortical excitatory projection neurons and glial cell-types. Cortical excitatory projection neurons are produced either directly or via intermediate progenitors, through indirect neurogenesis. How the extensive cortical cell-type diversity is generated during cortex development remains, however, a fundamental open question. How do RGPs quantitatively and qualitatively generate all the neocortical neurons? How does direct and indirect neurogenesis contribute to the establishment of neuronal and lineage heterogeneity? Whether RGPs represent a homogeneous and/or multipotent progenitor population, or if RGPs consist of heterogeneous groups is currently also not known. In this review, we will summarize the latest findings that contributed to a deeper insight into the above key questions.}, author = {Pipicelli, Fabrizia and Villalba Requena, Ana and Hippenmeyer, Simon}, issn = {0959-4388}, journal = {Current Opinion in Neurobiology}, publisher = {Elsevier}, title = {{How radial glia progenitor lineages generate cell-type diversity in the developing cerebral cortex}}, doi = {10.1016/j.conb.2025.103046}, volume = {93}, year = {2025}, } @article{19725, abstract = {Protein-protein interactions (PPIs) mediate many fundamental cellular processes. Control of PPIs through optically or chemically responsive protein domains has had a profound impact on basic research and some clinical applications. Most chemogenetic methods induce the association, i.e., dimerization or oligomerization, of target proteins, whilst the few available dissociation approaches either break large oligomeric protein clusters or heteromeric complexes. Here, we have exploited the controlled dissociation of a homodimeric oxidoreductase from mycobacteria (MSMEG_2027) by its native cofactor, F420, which is not present in mammals, as a bioorthogonal monomerization switch. Using X-ray crystallography, we found that in the absence of F420 MSMEG_2027 forms a unique domain-swapped dimer that occludes the cofactor binding site. Rearrangement of the N-terminal helix upon F420 binding results in the dissolution of the dimer. We then showed that MSMEG_2027 can be fused to proteins of interest in human cells and applied it as a tool to induce and release MAPK/ERK signalling downstream of a chimeric fibroblast growth factor receptor 1 (FGFR1) tyrosine kinase. This F420-dependent chemogenetic de-homodimerization tool is stoichiometric and based on a single domain and thus represents a novel mechanism to investigate protein complexes in situ.}, author = {Antoney, James and Kainrath, Stephanie and Dubowsky, Joshua G. and Ahmed, F. Hafna and Kang, Suk Woo and Mackie, Emily R.R. and Bracho Granado, Gustavo and Soares Da Costa, Tatiana P. and Jackson, Colin J. and Janovjak, Harald L}, issn = {1089-8638}, journal = {Journal of Molecular Biology}, number = {17}, publisher = {Elsevier}, title = {{A F420-dependent single domain chemogenetic tool for protein de-dimerization}}, doi = {10.1016/j.jmb.2025.169184}, volume = {437}, year = {2025}, } @article{19726, abstract = {The oxidation of biomass-derived compounds such as glucose within electrochemical cells enables both the energy-efficient production of hydrogen and the generation of additional added-value chemicals from biomass. However, for this biomass valorization approach to become commercially viable, selective, cost-effective, and highly active electrooxidation catalysts need to be developed. In this work, we detail the synthesis of a nickel (Ni) and zinc (Zn)-based electrocatalyst for the glucose oxidation reaction (GOR) to formic acid (FoA) via calcination of a Zn-based zeolitic imidazole framework (ZIF) functionalized with ethylenediamine and doped with Ni. The structure, morphology, and electrochemical performance of the catalysts towards the anodic GOR to FoA coupled with the cathodic hydrogen evolution reaction (HER) are subsequently studied. Chronopotentiometry tests with 0.1 M of glucose show a conversion of 94 % at 250 mA in only 70 min, with a Faradaic efficiency (FE) of 91 % toward the production of FoA. Meanwhile, at the cathode, the HER FE is close to 98 %.}, author = {Mejia-Centeno, Karol V. and Montaña-Mora, Guillem and Chacón-Borrero, Jesús and Xue, Qian and Gong, Li and Martí-Sánchez, Sara and Berlanga-Vázquez, Armando and Llorca, Jordi and Ibáñez, Maria and Arbiol, Jordi and Qi, Xueqiang and Martinez-Alanis, Paulina R. and Cabot, Andreu}, issn = {1385-8947}, journal = {Chemical Engineering Journal}, publisher = {Elsevier}, title = {{Glucose electrooxidation with simultaneous H2 production on nickel-zinc electrocatalysts derived from an ethylenediamine-functionalized zeolitic imidazole framework}}, doi = {10.1016/j.cej.2025.163491}, volume = {515}, year = {2025}, } @article{19727, abstract = {By studying some Clausen-like multiple Dirichlet series, we complete the proof of Manin's conjecture for sufficiently split smooth equivariant compactifications of the translation-dilation group over the rationals. Secondary terms remain elusive in general.}, author = {Wang, Victor}, issn = {1090-2082}, journal = {Advances in Mathematics}, publisher = {Elsevier}, title = {{Asymptotic growth of translation-dilation orbits}}, doi = {10.1016/j.aim.2025.110341}, volume = {475}, year = {2025}, } @article{19728, abstract = {Root system integrates multiple environmental cues, chiefly gravity and soil humidity, to anchor plants in soil and forage for water. While the mechanism of auxin-mediated root gravitropism is comparably well-understood, the root’s capability to grow toward moist soil for water uptake and drought avoidance, termed root hydrotropism, remains largely mysterious. Here, we provide key insights into the mechanism of hydrotropic growth and assign a role to the master regulator of hydrotropism, MIZU-KUSSEI 1 (MIZ1). We show that efficient hydrotropism requires the attenuation of antagonistically acting gravitropism, which is inhibited under drought conditions. Drought stress interferes with subcellular trafficking and the lateral mobility of PIN auxin transporters, which are polarly localized at the root cell plasma membranes. This leads to defects in PIN2 polarity and gravity-induced polarization of PIN3, ultimately inhibiting gravity-induced auxin redistribution and root bending. The miz1 mutant is defective in all these regulations, and in support of MIZ1’s action on PINs, pin mutations rescue the hydrotropic defects in the miz1 mutant. These observations identify a mechanism for how drought via MIZ1 attenuates gravitropism to promote root hydrotropism for efficient water foraging under drought conditions.}, author = {Zhang, Yuzhou and Bao, Zhulatai and Smoljan, Adrijana and Liu, Yifan and Wang, Huihui and Friml, Jiří}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences}, number = {20}, publisher = {National Academy of Sciences}, title = {{Foraging for water by MIZ1-mediated antagonism between root gravitropism and hydrotropism}}, doi = {10.1073/pnas.2427315122}, volume = {122}, year = {2025}, } @article{19729, abstract = {From anthropogenic litter carried by ocean currents to plant stems travelling through the atmosphere, geophysical flows are often seeded with elongated, fibre-like particles. In this study, we used a large-scale laboratory model of a tidal current – representative of a widespread class of geophysical flows – to investigate the tumbling motion of long, slender and floating fibres in the complex turbulence generated by flow interactions with a tidal inlet. Despite the non-stationary, non-homogeneous and anisotropic nature of this turbulence, we find that long fibres statistically rotate at the same frequency as eddies of similar size, a phenomenon called scale selection, which is known to occur in ideal turbulence. Furthermore, we report that the signal of the instantaneous transverse velocity difference between the fibre ends changes significantly from the signal produced by the flow in the fibre surroundings, although the two are statistically equivalent. These observations have twofold implications. On the one hand, they confirm the reliability of using the end-to-end velocity signal of rigid fibres to probe the two-point transverse statistics of the flow, even under realistic conditions: oceanographers could exploit this observation to measure transverse velocity differences through elongated floats in the field, where superdiffusion complicates collecting sufficient data to probe two-point turbulence statistics at a fixed separation effectively. On the other hand, by addressing the dynamics of inertial range particles floating in the coastal zone, these observations are crucial to improving our ability to predict the fate of meso- and macro-litter, a size class that is currently understudied.}, author = {De Leo, Annalisa and Brizzolara, Stefano and Cavaiola, Mattia and He, Junlin and Stocchino, Alessandro}, issn = {1469-7645}, journal = {Journal of Fluid Mechanics}, publisher = {Cambridge University Press}, title = {{Rigid fibre transport in a periodic non-homogeneous geophysical turbulent flow}}, doi = {10.1017/jfm.2025.362}, volume = {1011}, year = {2025}, } @article{19730, abstract = {Feigenbaum universality is shown to occur in subcritical shear flows. Our testing ground is the counter-rotation regime of the Taylor–Couette flow, where numerical calculations are performed within a small periodic domain. The accurate computation of up to the seventh period-doubling bifurcation, assisted by a purposely defined Poincaré section, has enabled us to reproduce the two Feigenbaum universal constants with unprecedented accuracy in a fluid flow problem. We have further devised a method to predict the bifurcation diagram up to the accumulation point of the cascade based on the detailed inspection of just the first few period-doubling bifurcations. Remarkably, the method is applicable beyond the accumulation point, with predictions remaining valid, in a statistical sense, for the chaotic dynamics that follows.}, author = {Wang, Baoying and Ayats López, Roger and Deguchi, K. and Meseguer, A. and Mellibovsky, F.}, issn = {1469-7645}, journal = {Journal of Fluid Mechanics}, publisher = {Cambridge University Press}, title = {{Feigenbaum universality in subcritical Taylor-Couette flow}}, doi = {10.1017/jfm.2025.278}, volume = {1010}, year = {2025}, }