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Improving constraints on primordial non-Gaussianity from Quaia with a new cosmological observable: angular redshift fluctuations
No full textInternational audienceAngular redshift fluctuations (ARF) are a new cosmological observable, recently proposed in the literature. It measures the 2D angular deviations of the average redshift of a given matter tracer under an input redshift shell. Since it depends on the galaxy bias, it can be used to constrain primordial non-Gaussianity through the scale-dependent bias effect. We analyze a sample of quasars built upon the Gaia satellite and unWISE data, Quaia, to measure the local non-Gaussianity parameter . This sample is particularly suitable for measuring due to its large volume coverage. We measure the ARF power spectra from the Quaia catalog and combine their information with the 2D (projected) galaxy density and their cross-correlation with the PR4 CMB lensing maps lensing to jointly constrain . Assuming the universality relation, we measure at 68% confidence level by combining Quaia quasar angular density and ARF with the CMB lensing. This result is the second tightest constraint on using LSS two-point statistics to date and the best measurement achieved using two-point projected summary statistics, improving by 25% the previous measurement from Quaia. Our results motivate the inclusion of ARF as an additional cosmological observable in future 2D analysis of upcoming datasets from large surveys
Fast and General Automatic Differentiation for Finite-State Methods
No full textWe propose a new method, that we coined the “morphism-trick”, to integrate custom implementations of vector-Jacobian products in automatic differentiation softwares, applicable to a wide range of semiring-based computations. Our approach leads to efficient and semiring-agnostic implementations of the backward pass of dynamic programming algorithms. For the particular case of finite-state methods, we introduce an algorithm that computes and differentiates the ⊕-sum of all paths’ weight of a finite-state automaton. Results show that, with minimal effort from the user, our novel library allows computing the gradient of a function w.r.t. to the weights of a finite state automaton orders of magnitude faster than state-of-the-art automatic differentiation systems. Implementations are made available via an open-source library distributed under a permissive license
Metric space valued Fréchet regression
No full textWe consider the problem of estimating the Fréchet and conditional Fréchet mean from data taking values in separable metric spaces. Unlike Euclidean spaces, where well-established methods are available, there is no practical estimator that works universally for all metric spaces. Therefore, we introduce a computable estimator for the Fréchet mean based on random quantization techniques and establish its universal consistency across any separable metric spaces. Additionally, we propose another estimator for the conditional Fréchet mean, leveraging data-driven partitioning and quantization, and demonstrate its universal consistency when the output space is any Banach space
High-Resolution Infrared Spectroscopy and ASAP Analysis of Cyclopentadiene: The Vibrational Modes below 860 cm–1 and the ν21 Mode at 961 cm–1
No full textInternational audienceThe spectroscopic fingerprints of vibrationally excited states of astronomical molecules are interesting for multiple reasons. They are excellent temperature probes of the corresponding astronomical regions and are thought to be the origin of many unknown lines in astronomical survey spectra. Rovibrational spectra provide accurate vibrational energies and can guide subsequent pure rotational studies. The Automated Spectral Assignment Procedure (ASAP) greatly simplifies the rovibrational analysis when the rotational spectrum of either the upper or lower vibrational state is known with a high degree of accuracy (e.g., from a rotational analysis). Here, we present a new implementation of ASAP for the analysis of cyclopentadiene, a cyclic pure hydrocarbon that has already been detected astronomically toward the cold core of the Taurus Molecular Cloud. Using the synchrotron radiation extracted by the AILES beamline of the SOLEIL facility, we recorded mid- and far-infrared high-resolution spectra of cyclopentadiene. We analyzed the rovibrational spectrum of the ν21 fundamental (961 cm–1) with ASAP and used ASAP2 to determine the vibrational energies of the eight vibrational modes below 860 cm–1. ASAP2 is an extension of ASAP for rovibrational bands where the rotational structures of the lower and upper states are known with high accuracy, leaving only the vibrational band center to be determined. The presented rovibrational fingerprints agree with the results from pure rotational spectroscopy, demonstrating the efficiency and reliability of our new ASAP implementation
Overdense fireworks in GOODS-N: Unveiling a record number of massive dusty star-forming galaxies at z ∼ 5.2 with the N2CLS
No full textInternational audienceHigh-density environments, such as early galaxy overdensities, play a critical role in hierarchical structure formation and galaxy evolution, providing an ideal setting for accelerated galaxy growth. The GOODS-N overdensity at z ≃ 5.2 has long been known, but its full extent and richness have only recently been revealed by JWST observations. It is highly elongated along the line of sight, spanning nearly 30 cMpc. We investigated its dusty galaxy population using the NIKA2 Cosmological Legacy Survey (N2CLS). Within this overdensity, we identify five luminous dusty starbursts that are spectroscopically confirmed, along with three additional candidates supported by robust photometric redshifts. Three of the spectroscopically confirmed galaxies (N2GN_1_01, 06, and 23, known as GN10, HDF850.1, and S3, respectively) had already been recognised as members of this exceptional structure. We report the discovery of N2GN_1_13 at z spec = 5.182, a massive dusty star-forming galaxy that we confirmed as part of the overdensity through targeted NOEMA follow-up observations of the N2CLS. In addition, by combining our analysis with JWST/FRESCO data, we identified another dusty galaxy at z spec = 5.201 (N2GN_1_61). The eight dusty galaxies are massive (with a median stellar mass of ∼9 × 10 10 M ⊙ ) and highly obscured (with a median A V of ∼3.3) and caught in a short-lived yet extreme starburst phase at z ∼ 5.2. Their high star formation rates (with a median of ∼590 M ⊙ yr −1 ), efficient baryon to stellar mass conversion ( ϵ ★ > 20% for 75% of the sample), and substantial gas reservoirs and dust content suggest rapid evolution and imminent quenching. Six of these galaxies reside in overdense filaments; the remaining two may trace new distinct structures, which will have to be spectroscopically confirmed. These few dusty galaxies dominate the star formation within the overdensity, contributing more than the numerous H α emitters, and surpassing the cosmic average star formation rate density for this epoch. The presence of numerous very massive, dusty, and intensely star-forming galaxies at z ∼ 5.2 shows that rapid stellar and dust mass assembly was already underway within the first billion years of cosmic history in overdense environments. Their properties, likely driven by efficient gas inflows along cosmic filaments in protocluster regions, suggest an accelerated evolution that current models and simulations have difficulty reproducing
LDG-PCGC: Lossless Dynamically Grouped Point Cloud Geometry Compression
No full textInternational audiencePoint clouds are an essential representation of 3D scenes and objects, but their growing data volume poses significant challenges for storage and transmission, highlighting the need for efficient and practical compression techniques. We propose a novel framework—Lossless Dynamically Grouped Point Cloud Geometry Compression (LDGPCGC). First, the k Nearest Neighbor (kNN)-based Transformer Occupancy Probability Estimator (KTOPE) jointly models spatial dependencies and predicts voxel occupancy, enhancing representation capacity. Then, the Probability-based Dynamic 8-stage Lossless Coder (PDELC) further enhances compression efficiency by employing a dynamic grouping strategy to achieve more accurate voxel occupancy probability estimation, thereby reducing bit consumption. In the lossless compression setting, our method achieves a 48.4% compression ratio (CR) improvement over the MPEG standard GPCC and a 7.7% gain compared with state-of-the-art learning-basedapproaches, demonstrating superior efficiency and spatial context modeling
An Integrated Beetle Antennae Search–Enabled Navigation Framework for Omnidirectional AGVMobile Robots in Unknown Environments
No full textInternational audienceThe Beetle Antennae Search algorithm is a relatively one of the recent optimization approach inspired by the foraging behavior of long-horn beetles, that copy how they use their antennae to explore the environment. This algorithm due to its simple structure and derivative-free nature, is well suited for robotic applications with limited computational resources. Despite many BAS-based navigation studies still handle path planning and control independently, or apply BAS only as an offline trajectory optimization tool. As a result, less attention has been given to implement it in the real-time navigation framework. On the other hand, Mobile robots, in an unseen environment cannot work these problems separately rather they must continuously detect obstacles, update their environment model, keep re-planning safe routes, adjust control gains, and follow a predetermined reference trajectory. An integrated BAS-enabled navigation combining Simultaneous Localization and Mapping framework for an omnidirectional mobile robot in CoppeliaSim is presented in this research. A LiDAR-based occupancy grid is updated continually during motion, and obstacle detection via SLAM is used to improve safety. A modified A* algorithm is used to create collision-free avoidance pathways, which are then smoothed. At the same time, a BAS-driven adaptive PID controller is used to adjust the gains by using trajectory deviation as a feedback signal. To enable precise path following, a nine-sensor infrared array is used for line tracking. The integrated system can follow smoothed avoidance paths, calculate safe bypasses, identify impediments, and return to the original path. In the experiments, the system was tested in two scenarios - no obstacles and with three levels of obstacles. The results indicated higher performance when SLAM and BAS used together than conventional PID based navigation while software simulation of SLAM often hurting the performance as well
A Theoretical Proposal to Localize and Determine the Amount of Methane, Ammonia and Carbon Dioxide in Nano-Cages of Water Clathrate Through the Space Infrared Spectroscopic Observations
No full textInternational audienceThis paper investigates the different relaxation channels of a single symmetric top NH3 and a spherical top CH4 molecule trapped at low temperature in a clathrate hydrate nano-cage in the infrared absorption domain of their vibrational degrees of freedom. The approach utilizes the Born–Oppenheimer approximation and the extended site inclusion model applied to CO2 in a previous work, which was based on pairwise atom–atom effective interaction potentials. The calculations show that trapping the methane or ammonia molecule is energetically more favorable in a type sI clathrate structure than in an sII one, and entropic considerations show that methane can be released much more easily than ammonia from clathrate hydrate nano-cages. In the small (s) and large (l) nano-cages with the sI structure, the CH4 molecule exhibits a more or less perturbed rotational motion, while the NH3 molecule shows a strongly hindered orientational motion that tends to a three-dimension librational motion (oscillation motion) around its orientational equilibrium configuration. The calculated orientational energy level schemes are quite different from those of the molecular free rotation. In the static field inside the cage, degenerate ν3 and ν4 vibrational modes of methane and ammonia molecules are shifted and split. Moreover, for ammonia molecules, the ν1 and ν2 modes are shifted, and the inversion motion is no longer allowed. The non-radiative and radiative relaxation channels of CH4, NH3 and CO2 in clathrate nano-cages are discussed with reference to the matrix isolation spectroscopic results. Upon laser excitation, then, from the energy levels calculated for the different degrees of freedom, NH3 and CO2 are expected to fluoresce, while for CH4, non-radiative relaxation should lead to evaporation at the surface of clathrates. Experimental setups are suggested to localize and study these species underneath ice surfaces on distant planets or planetesimals from mobile detectors such as drones or CubeSats equipped with appropriate laser sources and telescopes with 2D imaging detectors
The longitudinal association between anticholinergic burden and cognitive‐functional decline among older adults
No full textInternational audienceAims Long‐term use of medications with anticholinergic properties has been associated with cognitive and functional decline among older adults, yet these measures are typically assessed in isolation—potentially overlooking their interrelated nature. This study investigated the longitudinal association between anticholinergic burden and integrated cognitive‐functional measures in older adults. Methods Participants were drawn from S.AGES (France, 2009–2012). The total daily anticholinergic burden was assessed using the Anticholinergic Burden Scale (ACB) and the Anticholinergic and Sedative Burden Catalogue (ACSBC). We combined the Mini‐Mental State Examination (MMSE) with basic activities of daily living (BADLs), with instrumental activities of daily living (IADLs) or with both. Exploratory factor analyses (EFAs) and confirmatory factor analyses (CFAs) were conducted to explore dimensionality and model fit. The associations between the total burden and outcomes were estimated using generalized linear mixed models (GLMMs). Results Among 983 participants, a higher total daily ACB score was associated with poorer MMSE‐BADLs‐IADLs performance (OR = 1.25; 95% CI = [1.06–1.47]; p = 0.004) and MMSE‐IADLs (OR = 1.56; 95% CI = [1.30–1.88]; p < 0.001). Higher ACSBC scores showed similar associations with the MMSE‐BADLs‐IADLs (OR = 1.23; 95% CI = [1.08–1.40]; p < 0.001) and MMSE‐IADLs (OR = 1.40; 95% CI = [1.16–1.70]; p < 0.001). The three cognitive‐functional measures showed high internal consistency with comparative fit indexes (CFIs) of 0.9 and 0.95 and root mean squared error of approximations (RMSEAs) < 0.08, supporting a one‐factor model. Conclusions Our findings, based on combined measures in assessing cognitive‐functional decline in older adults, support incorporating anticholinergic burden assessment into routine care, particularly for patients aged ≥85 or those with CNS diseases and depression
Mobility-driven synthetic contact matrices as a scalable solution for real-time pandemic response modeling
No full textInternational audienceAccurately capturing time-varying human behavior remains a major challenge for real-time epidemic modeling and response. During the COVID-19 pandemic, synthetic contact matrices derived from mobility and behavioral data emerged as a scalable alternative to empirical contact surveys, yet their comparative performance remained unclear. Here, we systematically evaluate synthetic and empirical age-stratified contact matrices in France from March 2020 to May 2022, comparing contact patterns and their ability to reproduce observed epidemic dynamics. While both sources captured similar temporal trends in contacts, empirical matrices recorded 3.4 times more contacts for individuals under 19 than synthetic matrices during school-open periods. The model parameterized with synthetic matrices provided the best fit to hospital admissions and best captured hospitalization patterns for adolescents, adults, and seniors, whereas deviations remained for children across both models. Neither matrix allowed models to fully reproduce serological trends in children, highlighting the challenges both approaches face in capturing their disease-relevant contacts. The weekly update of synthetic matrices enabled smoother reconstructions of hospitalization trends during transitional phases, while empirical matrices required strong assumptions between survey waves. These findings support synthetic matrices as a reliable, flexible, cost-effective operational tool for real-time epidemic modeling, and highlight the need for routine collection of age-stratified mobility data to improve pandemic response