@article{21860, abstract = {Glutamate excitotoxicity is a cell death mechanism triggered by accumulation of glutamate in the extracellular space. The α-ketoglutarate dehydrogenase complex (αKGDHC), an enzyme of the tricarboxylic acid cycle, represents a branching point controlling glutamate formation and its consumption as a fuel. Hence, modulation of the activity of αKGDHC might alter the amount of glutamate available for excitotoxic effects. To address this hypothesis, hippocampal neurons in primary co-culture with glial cells were exposed to zero-Mg2 buffer to elicit excitotoxicity through N-methyl-D-aspartic acid (NMDA) receptor disinhibition. Pretreatment of the cultures with succinyl phosphonate, to inhibit αKGDHC, enhanced excitotoxity, whereas promotion of αKGDHC activity by pretreatment with thiamine caused an opposite action. Moreover, NMDA receptor currents – but not those mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors – were potentiated in neurons with impaired αKGDHC activity and diminished in neurons with boosted αKGDHC activity. The sensitization of NMDA receptors involved mGluR1 activation and was accompanied by enhanced neuronal discharge activity, elevated basal cytosolic Ca2+ levels, and augmented Ca2+ responses evoked by glutamate application. These results suggest that mGluR1-mediated potentiation of NMDA receptors contributes to a mechanism by which inhibition of αKGDHC might exacerbate glutamate excitotoxicity.}, author = {Goeschl, Vanessa and Hotka, Matej and Hochreiter, Bernhard and Hilber, Karlheinz and Boehm, Stefan and Kozlov, Andrey V. and Kubista, Helmut}, issn = {1477-9137}, journal = {Journal of Cell Science}, number = {8}, publisher = {The Company of Biologists}, title = {{α-ketoglutarate dehydrogenase complex activity modulates glutamate excitotoxicity via metabotropic regulation of NMDA receptors in primary cultures}}, doi = {10.1242/jcs.264420}, volume = {139}, year = {2026}, } @article{21881, abstract = {I review recent contributions on nonlinear Dirichlet forms. Then, I specialise to the case of 2- homogeneous and local forms. Inspired by the theory of Finsler manifolds and metric measure spaces, I establish new properties of such nonlinear Dirichlet forms, which are reminiscent of differential calculus formulae.}, author = {Brigati, Giovanni}, issn = {2730-9657}, journal = {La Matematica}, number = {2}, publisher = {Springer Nature}, title = {{Nonlinear Dirichlet forms, energy spaces, and calculus rules}}, doi = {10.1007/s44007-026-00217-w}, volume = {5}, year = {2026}, } @article{21882, abstract = {The nature of little red dots (LRDs) has largely been investigated through their continuum emission, with lines assumed to arise from a broad-line region. In this paper, we instead use recombination lines to infer the intrinsic properties of the central engine. Our analysis first reveals a tension between the ionizing properties implied from Hα and He ii λ4686. The high Hα EWs require copious H-ionizing photons, more than the bluest active galactic nucleus (AGN) ionizing spectra can provide. In contrast, He ii emission is marginally detected, and its low EW is, at most, consistent with the softest AGN spectra. The low He ii/Hβ (∼10−2, <20× local AGN median) further points to an unusually soft ionizing spectrum. We extend our analysis to dense gas envelopes (quasi-star/black-hole star) and find that hydrogen recombination lines become optically thick and lose diagnostic power, but He ii remains optically thin and a robust tracer. Photoionization modeling with Cloudy rules out standard AGN accretion disk spectra. Alternative explanations include exotic AGN with red rest-optical emission, high average optical depth (>10) from gas/dust, and soft ionizing spectra with abundant H-ionizing photons, consistent with, e.g., a cold accretion disk or a composite of AGN and stars. The latter is an intriguing scenario since high hydrogen densities are highly conducive for star formation, and nuclear star clusters are found in the vicinity of local massive black holes. While previous studies have mostly focused on features dominated by the absorbing hydrogen cloud, the He ii-based diagnostic proposed here represents a crucial step toward understanding the central engine of LRDs.}, author = {Wang, Bingjie and Leja, Joel and Katz, Harley and Inayoshi, Kohei and Cleri, Nikko J. and De Graaff, Anna and Hviding, Raphael E. and Van Dokkum, Pieter and Greene, Jenny E. and Labbé, Ivo and Matthee, Jorryt J and Mcconachie, Ian and Naidu, Rohan P. and Nelson, Erica J.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, publisher = {IOP Publishing}, title = {{The missing hard photons of Little Red Dots: Their incident ionizing spectra resemble massive stars}}, doi = {10.3847/1538-4357/ae5bab}, volume = {1003}, year = {2026}, } @article{21884, abstract = {We show that a randomly perturbed digraph, where we start with a dense digraph Dα and add a small number of random edges to it, will typically contain a fixed orientation of a bounded-degree spanning tree. This answers a question posed by Araujo, Balogh, Krueger, Piga and Treglown and generalizes the corresponding result for randomly perturbed graphs by Krivelevich, Kwan and Sudakov. More specifically, we prove that there exists a constant c=c(α,Δ) such that if T is an oriented tree with maximum degree Δ and Dα is an n-vertex digraph with minimum semidegree αn, then the graph obtained by adding cn uniformly random edges to Dα will contain T with high probability.}, author = {Morawski, Patryk and Petrova, Kalina H}, issn = {1077-8926}, journal = {Electronic Journal of Combinatorics}, number = {2}, publisher = {Electronic Journal of Combinatorics}, title = {{Randomly perturbed digraphs also have bounded-degree spanning trees}}, doi = {10.37236/13316}, volume = {33}, year = {2026}, } @article{21894, abstract = {The Dean–Kawasaki equation—one of the most fundamental SPDEs of fluctuating hydrodynamics—has been proposed as a model for density fluctuations in weakly interacting particle systems. In its original form, it is highly singular and fails to be renormalizable, even by approaches such as regularity structures and paracontrolled distributions, hindering mathematical approaches to its rigorous justification. It has been understood recently that it is natural to introduce a suitable regularization, for example, by applying a formal spatial discretization or by truncating high-frequency noise: This yields well-posed equations that should still precisely approximate the law of the particle density fluctuations. In the present work, we prove that a regularization in the form of a formal discretization of the Dean–Kawasaki equation indeed accurately describes density fluctuations in systems of weakly interacting diffusing particles: We show that, in suitable weak metrics, the law of fluctuations as predicted by the discretized Dean–Kawasaki SPDE approximates the law of fluctuations of the original particle system, up to an error that is of arbitrarily high order in the inverse particle number and a discretization error. In particular, the Dean– Kawasaki equation provides a means for efficient and accurate simulations of density fluctuations in weakly interacting particle systems.}, author = {Cornalba, Federico and Fischer, Julian L and Ingmanns, Jonas and Raithel, Claudia}, issn = {2168-894X}, journal = {The Annals of Probability}, keywords = {Weakly interacting particle systems, fluctuating hydrodynamics, Dean-Kawasaki equation, stochastic PDEs, numerical approximation}, number = {1}, pages = {155--215}, publisher = {Institute of Mathematical Statistics}, title = {{Density fluctuations in weakly interacting particle systems via the Dean–Kawasaki equation}}, doi = {10.1214/25-aop1763}, volume = {54}, year = {2026}, } @article{21895, abstract = {The mammalian brain organises knowledge about entities in the world and relationships between them using cognitive maps. When forming a cognitive map, there is a necessary trade-off between extending the map to make novel inferences, and storing a veridical copy of past experience. However, the neural mechanisms that control this trade-off remain unknown. Using a cross-scale approach that combines a pharmacological intervention in humans with neural network modelling, we show that the neuromodulator noradrenaline elicits a significant ‘spread of association’ across hippocampal cognitive maps. This neural spread of association can be explained by changes in synaptic plasticity that predict overgeneralisation in behaviour. Thus, elevated noradrenaline during learning increases the ‘smoothing kernel’ for plasticity across the cognitive map, allowing disparate memories to become linked and distorted.}, author = {Koolschijn, Renée S. and Parthasarathy, Prakriti and Browning, Michael and Przygodda, Xenia and Capitão, Liliana P. and Clarke, William T. and Vogels, Tim P and O’Reilly, Jill X. and Barron, Helen C.}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Noradrenaline causes a spread of association in the hippocampal cognitive map}}, doi = {10.1038/s41467-026-70659-x}, volume = {17}, year = {2026}, } @article{21897, abstract = {Ultracompact binary systems, consisting of two compact objects in an orbit $\lesssim 0.5 {\rm R}_\odot$, should exhibit measurable rates of orbital period change ($\dot{P} \ne 0$) due to the emission of gravitational waves (GWs). Measurements of $\dot{P}$ have so far been limited to the shortest-period ultracompact binaries ($\lesssim 20$  min). Among the AM CVn-type subclass, several works have proposed the presence of extra angular momentum loss beyond GW emission, with magnetic braking being a widely discussed mechanism. If present, this magnetic braking would dominate the angular momentum loss of AM CVn-type binaries with orbital periods $\gtrsim 30$ min. In this work, we present a long-term eclipse timing study of two AM CVn-type binaries, YZ LMi and Gaia14aae, with respective orbital periods of 28.3 min and 49.7 min and continuous observations since 2006 and 2015. Both systems show $\dot{P}$ consistent with zero within $2\sigma$. Their $3\sigma$ upper limits are $1.1 \times 10^{-13}\, {\rm s \, s}^{-1}$ and $9.7 \times 10^{-14}\, {\rm s \, s}^{-1}$, respectively. These non-detections are most simply explained by a scenario in which secular angular momentum loss is not substantially stronger than GW emission at all orbital periods, but is combined with deviations from the secular $\dot{P}$ whose time-scales span decades but whose amplitude is $\lesssim 10^{-13}\, {\rm s \, s}^{-1}$. Our non-detections of $\dot{P}$ represent a limit on the strength of any enhanced angular momentum loss beyond pure GW emission.}, author = {Green, Matthew J and Marsh, Thomas R and van Roestel, Joannes C and Wong, Tin Long Sunny and Belloni, Diogo and Kilic, Mukremin and Breedt, Elmé and Brown, Alex and Copperwheat, Chris M and Chakpor, Anurak and Dhillon, V S and Segura, Noel Castro and Dyer, Martin J and Garbutt, James and Jarvis, Dan and Kengkriangkrai, Vasu and Kennedy, Mark R and Kerry, Paul and Kupfer, Thomas and Littlefair, S P and McCormac, James and Munday, James and Parsons, Steven G and Pike, Eleanor and Pelisoli, Ingrid and Rodríguez-Gil, Pablo and Sahman, David I and Yates, Amalie}, issn = {1365-2966}, journal = {Monthly Notices of the Royal Astronomical Society}, keywords = {binaries: close – stars, dwarf novae – novae, cataclysmic variables – white dwarfs}, number = {3}, publisher = {Oxford University Press}, title = {{No period change in two long-period AM CVn binaries}}, doi = {10.1093/mnras/stag673}, volume = {548}, year = {2026}, } @article{21898, abstract = {We investigate the nature and spectroscopic diversity of early galaxies from a sample of 41 sources at $z\geqslant 10$ with James Webb Space Telescope (JWST)/NIRSpec prism observations. We compare the properties of strong ultraviolet (UV) line emitters, traced by intense C iv emission, with those of more ‘typical’ sources with weak or undetected C iv. The more typical (or ‘C iv-weak’) sources reveal significant scatter in their C iii] line strengths, UV continuum slopes, and physical sizes, spanning C iii] equivalent widths (EWs) of $\sim$1–51 Å, UV slopes of $\beta \sim -1.6$ to $-2.6$, and half-light radii of $\sim$50–1000 pc. In contrast, C iv-strong sources occupy the tail of these distributions, with C iii] EWs of 16–51 Å, UV slopes $\beta \lesssim -2.5$, compact morphologies ($r_{\rm 50} \lesssim 100$ pc), and elevated star formation surface densities ($\Sigma _{\rm SFR} \gtrsim 100\, M_\odot \, \mathrm{yr}^{-1}\, \mathrm{kpc}^{-2}$). These properties suggest concentrated starbursts that temporarily outshine the host galaxy. Comparing average properties from composite spectra, we find the diversity of the sample is primarily driven by bursty star formation on very short time-scales ($\le$3 Myr), with strong C iv emitters observed at the apex of the bursts and sources devoid of emission lines during relative inactivity. An apparent association between strong C iv and enhanced nitrogen abundance suggests both may be modulated by the same duty cycle, reflecting a generic mode of star formation. We show that active galactic nuclei are unlikely to contribute significantly to this duty cycle based on UV line diagnostics and photoionization models. Our results support a picture whereby brief bursts and lulls can explain the spectral diversity and early growth of bright galaxies in the first 500 Myr.}, author = {Roberts-Borsani, Guido and Oesch, Pascal A and Ellis, Richard and Weibel, Andrea and Giovinazzo, Emma and Bouwens, Rychard and Dayal, Pratika and Fontana, Adriano and Heintz, Kasper E and Matthee, Jorryt J and Meyer, Romain A and Pentericci, Laura and Shapley, Alice and Tacchella, Sandro and Treu, Tommaso and Walter, Fabian and Atek, Hakim and Bose, Sownak and Castellano, Marco and Fudamoto, Yoshinobu and Morishita, Takahiro and Naidu, Rohan P and Sanders, Ryan L and van der Wel, Arjen}, issn = {1365-2966}, journal = {Monthly Notices of the Royal Astronomical Society}, number = {3}, publisher = {Oxford University Press}, title = {{JWST spectroscopic insights into the diversity of galaxies in the first 500 Myr: Short-lived snapshots along a common evolutionary pathway}}, doi = {10.1093/mnras/stag701}, volume = {548}, year = {2026}, } @article{21899, abstract = {Cell extrusion is an essential mechanism for controlling cell density in epithelial tissues. Another essential element of epithelia is curvature, which is required to achieve complex shapes, like in the lung or intestine. Here, we introduce a three-dimensional bubbly vertex model to study the interplay between extrusion and curvature. We find a generic cellular bulging instability at topological defects, which is much stronger than for standard vertex models. Analyzing cell shapes in three-dimensional imaging data of spherical mouse colon organoids, we infer that pentagonal cells have an increased basal interfacial tension, suggesting that cells at topological defects react to the different force conditions. Using the bubbly vertex model, we show that such basal tensions stabilize against the predicted instability and result in better cell shape control than tissue-scale mechanisms such as lumen pressure and spontaneous curvature. Our theory suggests that epithelial curvature naturally leads to bulged and extrusionlike cell shapes because the interfacial curvature of individual cells at the defects strongly amplifies buckling effected by tissue-scale topological defects in elastic sheets. Our results highlight the complex interplay of forces across scales in three-dimensional tissue organization.}, author = {Drozdowski, Oliver M and Kocameşe-Tamgac𝚤, Büşra and Boonekamp, Kim E. and Boutros, Michael and Schwarz, Ulrich S.}, issn = {2160-3308}, journal = {Physical Review X}, number = {2}, publisher = {American Physical Society}, title = {{Cell bulging and extrusion in a three-dimensional bubbly vertex model for curved epithelial sheets}}, doi = {10.1103/x82g-cq7n}, volume = {16}, year = {2026}, } @article{21914, abstract = {Cyclic adenosine monophosphate (cAMP) is a fundamental second messenger involved in diverse signaling pathways across both animals and plants. While the role of 3′,5′-cAMP has been extensively characterized, the biological significance of its structural isomer, 2′,3′-cAMP, remains largely unexplored, particularly in plants. Here, we show that 2′,3′-cAMP and 3′,5′-cAMP represent parallel signaling systems in Arabidopsis thaliana, with different enzymatic origins and largely distinct downstream effects. In vitro enzymatic assays show that plant adenylate cyclases (ACs), including AFB5 and HpAC1, produce specifically 3′,5′-cAMP from ATP, whereas the TIR domain of protein L7 also catalyzes the formation of 2′,3′-cAMP from RNA. Comprehensive multiomics analyses reveal that two isomers elicit distinct yet partially overlapping metabolic, proteomic, and transcriptional response: 2′,3′-cAMP activates broad, stress-adaptive gene expression reprogramming, while 3′,5′-cAMP fine-tunes responses related to nutrient status and cellular homeostasis. Our findings establish the existence of dual cAMP signaling systems in plants, each with specialized functions and provide insights into the complex regulatory networks governing plant physiology.}, author = {Li, Mingyue and Chodasiewicz, Monika and Muraleedharan, Malavika and Lopez, Israel M. and Gorka, Michal and Kerber, Olga and Alotaibi, Saqer S. and Nelson, Andrew D.L. and Lenobel, Rene and Friedecká, Jaroslava and Skirycz, Aleksandra and Friml, Jiří}, issn = {2375-2548}, journal = {Science Advances}, number = {19}, publisher = {AAAS}, title = {{Biogenesis and downstream effects of 3',5' and 2',3' cAMP isomers in plants}}, doi = {10.1126/sciadv.aea7828}, volume = {12}, year = {2026}, } @article{21915, abstract = {Hydrological models commonly use very simple snow accumulation and melt models based on air temperature information, namely, a temperature threshold for snow accumulation as well as for snowmelt, and a melt factor. This utility emerges due to the simplicity, efficiency, and generally good performance of such models if sufficient calibration information is available. At scales beyond single gauged catchments, the estimation and evaluation of the temperature thresholds and the melt factor has been difficult due to a lack of observations on snow accumulation and melt. Using a recently published Northern Hemisphere snow water equivalent dataset (NH-SWE) and co-located climate station observations of temperature and precipitation (4736 stations across the Northern Hemisphere), this work estimates melt factors and temperature thresholds for snow modelling based on station observations and provides the first large-scale and long-term (1950–2023) evaluation of a simple temperature-index snow model and its parameters across a diverse range of snow climates. Our study reveals that the 0 °C as precipitation-phase threshold captures most snowfall days (89 %) and the 0 °C as snowmelt initiation threshold captures most snowmelt days (76 %). Adjusting large-scale uniform threshold values does not consistently improve performance across all snow accumulation and melt metrics. Estimated melt factors based on observations converge towards 3–5 mm (°C d)−1 for deeper snowpack climates (peak snow water equivalent >300 mm), but their estimation may be more challenging for colder climates with shallower snowpacks (<300 mm), conditions where the derived melt factors cover a wider range (1 to 12 mm (°C d)−1) and a much higher interannual and spatial variability. The temperature-index snow model performs consistently well, on average, across the available Northern Hemisphere data set for estimating long-term mean values of seasonal snow cover onset, snowmelt season onset, mean snow accumulation and snowmelt rates, but challenges may arise due to biases in temperature records or solid precipitation undercatch. Peak snow water equivalent is likely underestimated for deep or alpine snowpacks, while it is likely overestimated for shallow snowpacks in the coldest and continental climates. The best median performance of the temperature-index approach lies on relatively shallow snowpacks in temperate climates. This study provides valuable insights into temperature-threshold snowfall modelling and temperature-index melt modelling for applications across diverse climates and environments, and the results should help refine regional modelling approaches to enhance our understanding of snowpack responses to global warming.}, author = {Fontrodona-Bach, Adrià and Schaefli, Bettina and Woods, Ross and Larsen, Joshua R.}, issn = {1607-7938}, journal = {Hydrology and Earth System Sciences}, number = {9}, pages = {2613--2636}, publisher = {Copernicus Publications}, title = {{Estimating robust melt factors and temperature thresholds for snow modelling across the Northern Hemisphere}}, doi = {10.5194/hess-30-2613-2026}, volume = {30}, year = {2026}, } @article{21917, abstract = {A defining feature of quantum many-body systems is the exponential scaling of the Hilbert space with the number of degrees of freedom. This exponential complexity naïvely renders a complete state characterization, for instance via the complete set of bipartite Renyi entropies for all disjoint regions, a challenging task. Recently, a compact way of storing subregions' purities by encoding them as amplitudes of a fictitious quantum wave function, known as entanglement feature, was proposed. Notably, the entanglement feature can be a simple object even for highly entangled quantum states. However the complexity and practical usage of the entanglement feature for general quantum states has not been explored. In this work, we demonstrate that the entanglement feature can be efficiently learned using only a polynomial amount of samples in the number of degrees of freedom through the so-called tensor cross interpolation (TCI) algorithm, assuming it is expressible as a finite bond dimension MPS. We benchmark this learning process on Haar and random MPS states, confirming analytic expectations. Applying the TCI algorithm to quantum eigenstates of various one dimensional quantum systems, we identify cases where eigenstates have entanglement feature learnable with TCI. We conclude with possible applications of the learned entanglement feature, such as quantifying the distance between different entanglement patterns and finding the optimal one-dimensional ordering of physical indices in a given state, highlighting the potential utility of the proposed purity interpolation method.}, author = {Kolisnyk, Dmytro and Medina Ramos, Raimel A and Vasseur, Romain and Serbyn, Maksym}, issn = {2521-327X}, journal = {Quantum}, publisher = {Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften}, title = {{Tensor cross interpolation of purities in quantum many-body systems}}, doi = {10.22331/q-2026-05-22-2114}, volume = {10}, year = {2026}, } @phdthesis{21918, author = {Khudiakova, Kseniia}, issn = {2663-337X}, pages = {89}, publisher = {Institute of Science and Technology Austria}, title = {{How epistasis and purifying selection shape genetic diversity}}, doi = {10.15479/AT-ISTA-21918}, year = {2026}, } @article{21928, abstract = {Antibiotic combination in time and space is a key strategy to combat antimicrobial resistance. The success of such treatment designs requires their robust efficacy across treatment conditions and a pathogen’s genomic diversity. This study found that an initial treatment with a β-lactam antibiotic causes robust cellular sensitization towards an aminoglycoside antibiotic across the high-risk human pathogen Pseudomonas aeruginosa, including resistant strains. This phenomenon of cellular sensitization, termed negative hysteresis, is modulated by the Cpx envelope stress response system and linked to membrane stress during growth. The increase in efficacy is achieved through a β-lactam induced elevated cellular uptake of the subsequently administered aminoglycoside. Negative hysteresis and the Cpx system are linked in several cases to the expression of synergistic drug interactions, thus enhancing efficacy of antibiotic combinations. Overall, our study identifies the phenomenon of negative hysteresis as a robustly inducible phenotype and thus a unique focus for optimizing antimicrobial therapy.}, author = {Buchholz, Florian and Upterworth, Lina M. and Tueffers, Leif and Groth, Espen E. and Haas, Kira and Schütz, Daniel and Savietto Scholz, Abigail and Batra, Aditi and Pal, Surajit and Banerjee, Samarpita and Dubey, Badri N. and Franzenburg, Sören and Kalsdorf, Barbara and Rabe, Klaus F. and Nurjadi, Dennis and Rupp, Jan and Andersson, Dan I. and Sondermann, Holger and Bramkamp, Marc and Römhild, Roderich and Schulenburg, Hinrich}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Robust antibiotic sensitization of pathogenic Pseudomonas aeruginosa via negative hysteresis in the cell envelope}}, doi = {10.1038/s41467-026-71178-5}, volume = {17}, year = {2026}, } @article{21929, abstract = {The import of proteins into mitochondria poses fundamental mechanistic challenges: aggregation-prone precursor proteins must be maintained in aqueous compartments and threaded through narrow pores without becoming stuck or mislocalized. Recent evidence from mitochondrial protein import studies and other chaperone systems underscores the critical role of dynamics in balancing sufficiently tight binding, promiscuity, specificity, and release. Dynamic binding of client precursor proteins to import machinery components arises naturally from the avidity of their interactions. Conformational entropy enhances their stability, while the multivalent nature of these interactions ensures that client transfer to downstream insertases occurs without a substantial energy barrier. Here, we discuss this emerging paradigm of dynamic protein handling, using examples where dynamic structures have been resolved and highlight outstanding questions.}, author = {Schneider, Jakob and Guillerm, Undina and Simoes Pereira, Caroline and Schanda, Paul}, issn = {1469-896X}, journal = {Protein Science}, number = {6}, publisher = {Wiley}, title = {{Dynamic disorder is crucial for mitochondrial protein import}}, doi = {10.1002/pro.70630}, volume = {35}, year = {2026}, } @article{21930, abstract = {We present the discovery of extreme nitrogen enrichment by Wolf Rayet nitrogen (WN) stars in the metal-poor (∼10%Z⊙), lensed, compact (Reff ∼ 20 pc) galaxy RXCJ2248 at z = 6.1, revealed by unprecedentedly deep JWST/NIRSpec medium-resolution spectroscopy from the GLIMPSE-D Survey. The exquisite signal-to-noise ratio reveals multiple high-ionization nebular lines and broad Balmer and [O III] components (FWHM ∼700–3000 km s −1 ). We detect broadened He II λ1640 and λ4687 (FWHM ∼ 530 km s −1 ) and strong N III λ4642 emission consistent with a population of WN stars, making RXCJ2248 the most distant galaxy with confirmed Wolf Rayet (WR) features to date. We measure the multiphase nebular density across five ions, the direct-method metallicity ( 12 + log(O/H) = 7.753 ± 0.025 ), and a nonuniform elemental enrichment pattern of extreme N/O enhancement ( log(N/O) = 0.391 ± 0.037 from N+, N+2 , and N+3 ) but suppressed C/O relative to empirical C/N trends. We show that this abundance pattern can be explained by enrichment from a dual-burst with a low WR carbon/WN ratio, as expected at low metallicities. Crucially, these signatures can only arise during a brief, rare evolutionary window shortly after a burst (∼3–6 Myr), when WN stars dominate chemical feedback but before dilution by later yields (e.g., supernovae). The observed frequency of strong N emitters at high−z implies a ∼50 Myr burst duty cycle, suggesting that N/O outliers may represent a brief but ubiquitous phase in the evolution of highly star-forming early galaxies. The WN detection in RXCJ2248, therefore, provides the first direct evidence of WR-driven nitrogen enrichment in the first billion years of the Universe and a novel timing argument for the bursty star formation cycles that shaped galaxies at cosmic dawn.}, author = {Berg, Danielle A. and Naidu, Rohan P. and Chisholm, John and Atek, Hakim and Fujimoto, Seiji and Kokorev, Vasily and Furtak, Lukas J. and Kobayashi, Chiaki and Schaerer, Daniel and Adamo, Angela and Fei, Qinyue and Korber, Damien and Matthee, Jorryt J and Marques-Chaves, Rui and Martinez, Zorayda and Mcquinn, Kristen B.W. and Muñoz, Julian B. and Oesch, Pascal A. and Saldana-Lopez, Alberto and Stark, Daniel P. and Stephenson, Mabel G. and Hsiao, Tiger Yu Yang}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{A fleeting GLIMPSE of N/O enrichment at cosmic dawn: Evidence for Wolf Rayet N stars in a z = 6.1 galaxy}}, doi = {10.3847/1538-4357/ae5e4c}, volume = {1003}, year = {2026}, } @inproceedings{21932, abstract = {We present LLMQ, an end-to-end CUDA/C++ implementation for medium-sized language-model training, e.g. 3B to 32B parameters, on affordable, commodity GPUs. These devices are characterized by low memory availability and slow communication compared to datacentre-grade GPUs. Consequently, we showcase a range of optimizations that target these bottlenecks, including activation checkpointing, offloading, and copy-engine based collectives. LLMQ is able to train or fine-tune a 7B model on a single 16GB mid-range gaming card, or a 32B model on a workstation equipped with 4 RTX 4090s. This is achieved while executing a standard 8-bit training pipeline, without additional algorithmic approximations, and maintaining FLOP utilization of around 50%. The efficiency of LLMQ rivals that of production-scale systems on much more expensive cloud-grade GPUs.}, author = {Schultheis, Erik and Alistarh, Dan-Adrian}, booktitle = {2nd Conference on Parsimony and Learning}, issn = {2640-3498}, location = {Stanford, CA, United States}, pages = {265--284}, publisher = {ML Research Press}, title = {{LLMQ: Efficient lower-precision LLM training for consumer GPUs}}, volume = {328}, year = {2026}, } @article{21933, abstract = {We consider the liquid drop model with a positive background density in the thermodynamic limit. We prove a two-term asymptotics for the ground state energy per unit volume in the dilute limit. Our proof justifies the expectation that optimal configurations consist of droplets of unit size that arrange themselves according to minimizers for the Jellium problem for point particles. In particular, we provide the first rigorous derivation of what is known as the gnocchi phase in astrophysics.}, author = {Frank, Rupert L. and Lewin, Mathieu and Seiringer, Robert}, issn = {1097-0312}, journal = {Communications on Pure and Applied Mathematics}, publisher = {Wiley}, title = {{Liquid drop model for nuclear matter in the low density limit}}, doi = {10.1002/cpa.70039}, year = {2026}, } @article{21934, abstract = {An accurate characterisation of the physical properties of galaxies at cosmic dawn is key to understanding the origin of the high abundance of UV-bright galaxies at z≳10. We exploit deep (9.1-hour exposure time) NIRSpec PRISM observations of GHZ2 to constrain the sources of ionising radiation and the properties of the interstellar medium (ISM) in this bright, compact, and highly ionising galaxy at z=12.3. We measure with high significance the prominent N IV, C IV, He II, O III, C III, O II, and Ne III emission features previously detected in shallower observations, and confirm the detection of the N III] λ1750 multiplet, yielding tight constraints on the N/O ratio, which is found to be ≃2 times the solar value. We also detect the Mg II λ2800, [Fe IV] λ2833 and Si II λ1812 doublets, the H8+HeI λλ3889 blend, and the Si IV+O IV] λλ1400 absorption complex. The O III λ3133 fluorescence line is only detected in the first observing epoch, implying variability on a rest-frame time span of 19 days, strongly suggesting the presence of an active nucleus. Combining the NIRSpec dataset with available optical and far-infrared constraints from MIRI and ALMA, we show that the emission spectrum of GHZ2 cannot be reproduced by single-density spectro-photometric models, even under extreme assumptions on the ionisation parameter and electron density. Multi-zone photoionisation modelling performed with the HOMERUN code demonstrates that star formation must be occurring in a strongly stratified ISM, where both low-/intermediate-density gas and high-density regions (log(ne/cm−3 ) ≳ 4) coexist. The GHZ2 emission landscape is consistent with either a composite star-formation plus AGN scenario, or with star formation occurring in a combination of radiation- and matter-bounded regions. Purely radiation-bounded stellar models fail to reproduce the observed He II emission, making an additional hard ionising component unavoidable.}, author = {Castellano, M. and Napolitano, L. and Moreschini, B. and Calabrò, A. and Christensen, L. and Llerena, M. and Bakx, T. J.L.C. and Belfiore, F. and Bevacqua, D. and Dickinson, M. and Fontana, A. and Gandolfi, G. and Gasparetto, T. and Marconi, A. and Mascia, Sara and Merlin, E. and Morishita, T. and Nanayakkara, T. and Paris, D. and Pentericci, L. and Pérez-Díaz, B. and Roberts-Borsani, G. and Rojas-Ruiz, S. and Santini, P. and Treu, T. and Vanzella, E. and Vulcani, B. and Wang, X. and Yoon, I. and Zavala, J.}, issn = {2565-6120}, journal = {The Open Journal of Astrophysics}, publisher = {Maynooth Academic Publishing}, title = {{Investigating ionising sources and the complex interstellar medium of GHZ2 at z=12.3}}, doi = {10.33232/001c.160281}, volume = {9}, year = {2026}, } @inproceedings{21949, abstract = {Cardiac T1 mapping provides critical quantitative insights into myocardial tissue composition, enabling the assessment of pathologies such as fibrosis, inflammation, and edema. However, the inherently dynamic nature of the heart imposes strict limits on acquisition times, making high-resolution T1 mapping a persistent challenge. Compressed sensing (CS) approaches have reduced scan durations by undersampling k-space and reconstructing images from partial data, and recent studies show that jointly optimizing the undersampling patterns with the reconstruction network can substantially improve performance. Still, most current T1 mapping pipelines rely on static, hand-crafted masks that do not exploit the full acceleration and accuracy potential. Furthermore, most existing methods do not levarage the physical T1 decay model in optimization. In this work, we introduce T1- PILOT: an end-to-end method that explicitly incorporates the T1 signal relaxation model into the sampling–reconstruction framework to guide the learning of non-Cartesian trajectories, cross-frame alignment, and T1 decay estimation. Through extensive experiments on the CMRxRecon dataset, T1-PILOT significantly outperforms several baseline strategies (including learned single-mask and fixed radial or golden-angle sampling schemes), achieving higher T1 map fidelity at greater acceleration factors. In particular, we observe consistent gains in PSNR and VIF relative to existing methods, along with marked improvements in delineating finer myocardial structures. Our results highlight that optimizing sampling trajectories in tandem with the physical relaxation model leads to both enhanced quantitative accuracy and reduced acquisition times. Code for reproducing all experiments and results is available at https://github.com/tamirshor7/T1-PILOT}, author = {Shor, Tamir and Freiman, Moti and Baskin, Chaim and Bronstein, Alexander}, booktitle = {Medical Imaging with Deep Learning}, issn = {2640-3498}, keywords = {Cardiac T1 Mapping, Trajectory Optimization and Reconstruction, PhysicsInformed Deep-Learning}, location = {Taipei, Taiwan}, pages = {1969--1982}, publisher = {ML Research Press}, title = {{T1-PILOT: Physics-informed learned optimized trajectories for T1 mapping acceleration}}, volume = {315}, year = {2026}, }