Miracle-dz/UniFAR-FTUs huggingface dataset:
The hidden side of cosmic star formation at z > 3. Bridging optically dark and Lyman break galaxies with GOODS-ALMA

Our current understanding of the cosmic star formation history at z>3 is primarily based on UV-selected galaxies (i.e., LBGs). Recent studies of H-dropouts have revealed that we may be missing a large proportion of star formation that is taking place in massive galaxies at z>3. In this work, we extend the H-dropout criterion to lower masses to select optically dark/faint galaxies (OFGs), in order to complete the census between LBGs and H-dropouts. Our criterion (H>26.5 mag&[4.5]<25 mag) combined with a de-blending technique is designed to select not only extremely dust-obscured massive galaxies but also normal star-forming galaxies. In total, we identified 27 OFGs at z_phot>3 (z_med=4.1) in the GOODS-ALMA field, covering a wide distribution of stellar masses with log($M_{\star}$/$M_{\odot}$) = 9.4-11.1. We find that up to 75% of the OFGs with log($M_{\star}$/$M_{\odot}$) = 9.5-10.5 were neglected by previous LBGs and H-dropout selection techniques. After performing stacking analyses, the OFGs exhibit shorter gas depletion timescales, slightly lower gas fractions, and lower dust temperatures than typical star-forming galaxies. Their SFR_tot (SFR_ IR+SFR_UV) is much larger than SFR_UVcorr (corrected for dust extinction), with SFR_tot/SFR_UVcorr = $8\pm1$, suggesting the presence of hidden dust regions in the OFGs that absorb all UV photons. The average dust size measured by a circular Gaussian model fit is R_e(1.13 mm)=1.01$\pm$0.05 kpc. We find that the cosmic SFRD at z>3 contributed by massive OFGs is at least two orders of magnitude higher than the one contributed by equivalently massive LBGs. Finally, we calculate the combined contribution of OFGs and LBGs to the cosmic SFRD at z=4-5 to be 4 $\times$ 10$^{-2}$ $M_{\odot}$ yr$^{-1}$Mpc$^{-3}$, which is about 0.15 dex (43%) higher than the SFRD derived from UV-selected samples alone at the same redshift.
Generative Augmented Flow Networks

The Generative Flow Network is a probabilistic framework where an agent learns a stochastic policy for object generation, such that the probability of generating an object is proportional to a given reward function. Its effectiveness has been shown in discovering high-quality and diverse solutions, compared to reward-maximizing reinforcement learning-based methods. Nonetheless, GFlowNets only learn from rewards of the terminal states, which can limit its applicability. Indeed, intermediate rewards play a critical role in learning, for example from intrinsic motivation to provide intermediate feedback even in particularly challenging sparse reward tasks. Inspired by this, we propose Generative Augmented Flow Networks (GAFlowNets), a novel learning framework to incorporate intermediate rewards into GFlowNets. We specify intermediate rewards by intrinsic motivation to tackle the exploration problem in sparse reward environments. GAFlowNets can leverage edge-based and state-based intrinsic rewards in a joint way to improve exploration. Based on extensive experiments on the GridWorld task, we demonstrate the effectiveness and efficiency of GAFlowNet in terms of convergence, performance, and diversity of solutions. We further show that GAFlowNet is scalable to a more complex and large-scale molecule generation domain, where it achieves consistent and significant performance improvement.
Global epistasis on fitness landscapes

Epistatic interactions between mutations add substantial complexity to adaptive landscapes and are often thought of as detrimental to our ability to predict evolution. Yet, patterns of global epistasis, in which the fitness effect of a mutation is well-predicted by the fitness of its genetic background, may actually be of help in our efforts to reconstruct fitness landscapes and infer adaptive trajectories. Microscopic interactions between mutations, or inherent nonlinearities in the fitness landscape, may cause global epistasis patterns to emerge. In this brief review, we provide a succinct overview of recent work about global epistasis, with an emphasis on building intuition about why it is often observed. To this end, we reconcile simple geometric reasoning with recent mathematical analyses, using these to explain why different mutations in an empirical landscape may exhibit different global epistasis patterns—ranging from diminishing to increasing returns. Finally, we highlight open questions and research directions. This article is part of the theme issue ‘Interdisciplinary approaches to predicting evolutionary biology’.
Compressing Video Calls using Synthetic Talking Heads

We leverage the modern advancements in talking head generation to propose an end-to-end system for talking head video compression. Our algorithm transmits pivot frames intermittently while the rest of the talking head video is generated by animating them. We use a state-of-the-art face reenactment network to detect key points in the non-pivot frames and transmit them to the receiver. A dense flow is then calculated to warp a pivot frame to reconstruct the non-pivot ones. Transmitting key points instead of full frames leads to significant compression. We propose a novel algorithm to adaptively select the best-suited pivot frames at regular intervals to provide a smooth experience. We also propose a frame-interpolater at the receiver's end to improve the compression levels further. Finally, a face enhancement network improves reconstruction quality, significantly improving several aspects like the sharpness of the generations. We evaluate our method both qualitatively and quantitatively on benchmark datasets and compare it with multiple compression techniques. We release a demo video and additional information at https://cvit.iiit. ac.in/research/projects/cvit-projects/talking-video-compression.
Flexible Alignment Super-Resolution Network for Multi-Contrast MRI

Magnetic resonance imaging plays an essential role in clinical diagnosis by acquiring the structural information of biological tissue. Recently, many multi-contrast MRI super-resolution networks achieve good effects. However, most studies ignore the impact of the inappropriate foreground scale and patch size of multi-contrast MRI, which probably leads to inappropriate feature alignment. To tackle this problem, we propose the Flexible Alignment Super-Resolution Network (FASR-Net) for multi-contrast MRI Super-Resolution. The Flexible Alignment module of FASR-Net consists of two modules for feature alignment. (1) The Single-Multi Pyramid Alignment(S-A) module solves the situation where low-resolution (LR) images and reference (Ref) images have different scales. (2) The Multi-Multi Pyramid Alignment(M-A) module solves the situation where LR and Ref images have the same scale. Besides, we propose the Cross-Hierarchical Progressive Fusion (CHPF) module aiming at fusing the features effectively, further improving the image quality. Compared with other state-of-the-art methods, FASR-net achieves the most competitive results on FastMRI and IXI datasets. Our code will be available at \href{https://github.com/yimingliu123/FASR-Net}{https://github.com/yimingliu123/FASR-Net}.
TAN without a burn: Scaling Laws of DP-SGD

Differentially Private methods for training Deep Neural Networks (DNNs) have progressed recently, in particular with the use of massive batches and aggregated data augmentations for a large number of training steps. These techniques require much more computing resources than their non-private counterparts, shifting the traditional privacy-accuracy trade-off to a privacy-accuracy-compute trade-off and making hyper-parameter search virtually impossible for realistic scenarios. In this work, we decouple privacy analysis and experimental behavior of noisy training to explore the trade-off with minimal computational requirements. We first use the tools of R\'enyi Differential Privacy (RDP) to highlight that the privacy budget, when not overcharged, only depends on the total amount of noise (TAN) injected throughout training. We then derive scaling laws for training models with DP-SGD to optimize hyper-parameters with more than a $100\times$ reduction in computational budget. We apply the proposed method on CIFAR-10 and ImageNet and, in particular, strongly improve the state-of-the-art on ImageNet with a +9 points gain in top-1 accuracy for a privacy budget epsilon=8.
A lower bound on intergalactic magnetic fields from time variability of 1ES 0229+200 from MAGIC and Fermi/LAT observations

Extended and delayed emission around distant TeV sources induced by the effects of propagation of gamma rays through the intergalactic medium can be used for the measurement of the intergalactic magnetic field (IGMF). We search for delayed GeV emission from the hard-spectrum TeV blazar 1ES 0229+200 with the goal to detect or constrain the IGMF-dependent secondary flux generated during the propagation of TeV gamma rays through the intergalactic medium. We analyze the most recent MAGIC observations over a 5 year time span and complement them with historic data of the H.E. S.S. and VERITAS telescopes along with a 12-year long exposure of the Fermi/LAT telescope. We use them to trace source evolution in the GeV-TeV band over one-and-a-half decade in time. We use Monte Carlo simulations to predict the delayed secondary gamma-ray flux, modulated by the source variability, as revealed by TeV-band observations. We then compare these predictions for various assumed IGMF strengths to all available measurements of the gamma-ray flux evolution. We find that the source flux in the energy range above 200 GeV experiences variations around its average on the 14 years time span of observations. No evidence for the flux variability is found in 1-100 GeV energy range accessible to Fermi/LAT. Non-detection of variability due to delayed emission from electromagnetic cascade developing in the intergalactic medium imposes a lower bound of B>1.8e-17 G for long correlation length IGMF and B>1e-14 G for an IGMF of the cosmological origin. Though weaker than the one previously derived from the analysis of Fermi/LAT data, this bound is more robust, being based on a conservative intrinsic source spectrum estimate and accounting for the details of source variability in the TeV energy band. We discuss implications of this bound for cosmological magnetic fields which might explain the baryon asymmetry of the Universe.
NeRD++: Improved 3D-mirror symmetry learning from a single image

Many objects are naturally symmetric, and this symmetry can be exploited to infer unseen 3D properties from a single 2D image. Recently, NeRD is proposed for accurate 3D mirror plane estimation from a single image. Despite the unprecedented accuracy, it relies on large annotated datasets for training and suffers from slow inference. Here we aim to improve its data and compute efficiency. We do away with the computationally expensive 4D feature volumes and instead explicitly compute the feature correlation of the pixel correspondences across depth, thus creating a compact 3D volume. We also design multi-stage spherical convolutions to identify the optimal mirror plane on the hemisphere, whose inductive bias offers gains in data-efficiency. Experiments on both synthetic and real-world datasets show the benefit of our proposed changes for improved data efficiency and inference speed.
Self-energy flows in the two-dimensional repulsive Hubbard model

We study the two-dimensional repulsive Hubbard model by functional RG methods, using our recently proposed channel decomposition of the interaction vertex. The main technical advance of this work is that we calculate the full Matsubara frequency dependence of the self-energy and the interaction vertex in the whole frequency range without simplifying assumptions on its functional form, and that the effects of the self-energy are fully taken into account in the equations for the flow of the two-body vertex function. At Van Hove filling, we find that the Fermi surface deformations remain small at fixed particle density and have a minor impact on the structure of the interaction vertex. The frequency dependence of the self-energy, however, turns out to be important, especially at a transition from ferromagnetism to d-wave superconductivity. We determine non-Fermi-liquid exponents at this transition point.
INTERSTELLAR SILICATE DUST IN THE z = 0.685 ABSORBER TOWARD TXS 0218+357

We report the detection of interstellar silicate dust in the zabs = 0.685 absorber along the sightline toward the gravitationally lensed blazar TXS 0218+357. Using Spitzer Space Telescope Infrared Spectrograph data, we detect the 10 μm silicate absorption feature with a detection significance of 10. 7σ. We fit laboratory-derived silicate dust profile templates obtained from the literature to the observed 10 μm absorption feature and find that the best single-mineral fit is obtained using an amorphous olivine template with a measured peak optical depth of τ10 = 0.49 ± 0.02, which rises to τ10 ∼ 0.67 ± 0.04 if the covering factor is taken into account. We also detected the 18 μm silicate absorption feature in our data with a >3σ significance. Due to the proximity of the 18 μm absorption feature to the edge of our covered spectral range, and associated uncertainty about the shape of the quasar continuum normalization near 18 μm, we do not independently fit this feature. We find, however, that the shape and depth of the 18 μm silicate absorption are well matched to the amorphous olivine template prediction, given the optical depth inferred for the 10 μm feature. The measured 10 μm peak optical depth in this absorber is significantly higher than those found in previously studied quasar absorption systems. However, the reddening, 21 cm absorption, and velocity spread of Mg ii are not outliers relative to other studied absorption systems. This high optical depth may be evidence for variations in dust grain properties in the interstellar medium between this and the previously studied high redshift galaxies.
ALFALFA H i data stacking – I. Does the bulge quench ongoing star formation in early-type galaxies?

We have carried out an H i stacking analysis of a volume-limited sample of ∼5000 galaxies with imaging and spectroscopic data from GALEX and the Sloan Digital Sky Survey, which lie within the current footprint of the Arecibo Legacy Fast ALFA (ALFALFA) survey. Our galaxies are selected to have stellar masses greater than 1010 M⊙ and redshifts in the range 0.025 2.6 and with light profiles that are well fit by a De Vaucouleurs model. We then stack H i line spectra extracted from the ALFALFA data cubes at the 3D positions of the galaxies from these two samples in bins of stellar mass, stellar mass surface density, central velocity dispersion and NUV−r colour. We use the stacked spectra to estimate the average H i gas fractions /M* of the galaxies in each bin. Our main result is that the H i content of a galaxy is not influenced by its bulge. The average H i gas fractions of galaxies in both our samples correlate most strongly with NUV−r colour and with stellar surface density. The relation between average H i fraction and these two parameters is independent of concentration index C. We have tested whether the average H i gas content of bulge-dominated galaxies on the red sequence differs from that of late-type galaxies on the red sequence. We find no evidence that galaxies with a significant bulge component are less efficient at turning their available gas reservoirs into stars. This result is in contradiction with the ‘morphological quenching’ scenario proposed by Martig et al.
On the Decades-Long Stability of the Interstellar Wind through the Solar System

We have revisited the series of observations recently used to infer a temporal variation in the interstellar helium flow over the past forty years. Concerning the recent IBEX-Lo direct detection of helium neutrals, there are two types of precise and unambiguous measurements that do not rely on the exact response of the instrument: the count rate maxima as a function of the spin angle, which determines the ecliptic latitude of the flow, and the count rate maxima as a function of IBEX longitude, which determines a tight relationship between the ecliptic longitude of the flow and its velocity far from the Sun. These measurements provide parameters (and couples of parameters in the second case) that are remarkably similar to the canonical, old values. In contrast, the preferred choice of a lower velocity and higher longitude reported before from IBEX data is only based on the count rate variation (at each spin phase maximum) as a function of the satellite longitude, when drifting across the region of high fluxes. We have examined the consequences of dead-time counting effects and conclude that including them at a realistic level is sufficient to reconcile the data with the old parameters, calling for further investigations. We discuss the analyses of the STEREO pickup ion data and argue that the statistical method that has been preferred to infer the neutral flow longitude (instead of the more direct method based on the pickup ion maximum flux directions) is not appropriate. Moreover, transport effects may have been significant at the very weak solar activity level of 2007−2009, in which case the longitudes of the pickup ion maxima are only upper limits on the flow longitude. Finally, we found that using some flow longitude determinations based on UV glow data is not adequate. Based on this global study, and at variance with recent conclusions, we find no evidence for a temporal variability of the interstellar helium flow. This has implications for inner and outer heliosphere studies.
The size of the longest filament in the luminous red galaxy distribution

Filaments are one of the most prominent features visible in the galaxy distribution. Considering the luminous red galaxies in the Sloan Digital Sky Survey Data Release Seven (SDSS DR7), we have analysed the filamentarity in 11 nearly 2D sections through a volume limited subsample of these data. The galaxy distribution, we find, has excess filamentarity in comparison to a random distribution of points. We use a statistical technique 'Shuffle' to determine L MAX , the largest length-scale at which we have statistically significant filaments. We find that L MAx varies in the range 100-130 h -1 Mpc across the 11 slices, with a mean value L MAX = 110 ± 12 h -1 Mpc. Longer filaments, though possibly present in our data, are not statistically significant and are the outcome of chance alignments.
Evaluation of Torula yeast as a protein source in extruded feline diets

Abstract The objective of this work was to evaluate the use of a Torula yeast (TY) on diet processing, palatability, and total tract nutrient digestibility in extruded feline diets. Four dietary treatments were compared, differing by protein source: TY, pea protein concentrate (PP), soybean meal (SM), and chicken meal (CM). Diets were produced using a single-screw extruder under similar processing conditions. Palatability assessment was conducted as a split plate design where both first choice and intake ratio (IR) were determined. Apparent total tract digestibility (ATTD) of nutrients was estimated using Titanium dioxide as an indigestible marker. During diet production, specific mechanical energy of TY and SM (average of 187 kJ/kg) was greater (P < 0.05) than for PP (138 kJ/kg); however, CM was similar to all treatments (167 kJ/kg). Kibble diameter, piece volume, and sectional expansion ratio were greatest for TY (P < 0.05). Additionally, both bulk and piece density were lowest (P < 0.05) for TY. Kibble hardness was lower for TY and SM (P < 0.05; average of 2.10 Newtons) compared to CM and PP (average of 2.90 Newtons). During the palatability trial, TY was chosen first a greater number of times than CM (P < 0.05; 36 vs. 4, respectively), but differences were not found between TY and PP (25 vs. 15, respectively) or TY and SM (24 vs. 16, respectively). Cats had a greater IR (P < 0.05) of TY compared to CM and PP (0.88 and 0.73, respectively). However, there was no difference in preference between TY and SM. ATTD of dry matter (DM) and organic matter (OM) was greater (P < 0.05) for CM (87.43% and 91.34%, respectively) than other treatments. Both DM and OM ATTD of TY were similar (P < 0.05) to PP and SM (average of 86.20% and average of 89.76%, respectively). Ash ATTD was greater (P < 0.05) for cats fed TY and SM (average of 37.42%), intermediate for PP (32.79%), and lowest for CM (23.97%). Crude protein (CP) ATTD of TY was similar to all other treatments (average of 89.97%), but fat ATTD was lower (P < 0.05; 92.52%) than other treatments (93.76% to 94.82%). Gross energy ATTD was greater (P < 0.05) for CM than TY (90.97% vs. 90.18%, respectively); however, TY was similar to PP and SM (average of 90.22%). Total dietary fiber ATTD was similar between TY and CM (average of 66.20%) and greater (P < 0.05) than PP and SM (average of 58.70%). The TY used in this study facilitated diet formation, increased diet preference, and was highly digestible when fed to cats.
Evolution of oxygen and nitrogen abundances and nitrogen production mechanism in massive star-forming galaxies

Utilizing the observational data of 55 318 star-forming galaxies (SFGs) selected from the catalogue of MPA-JHU emission-line measurements for the Sloan Digital Sky Survey DR8, we investigate the galaxy downsizing effect of their O and N enrichments, and the nitrogen production mechanism in them. We show the redshift evolution of O and N abundances and specific star formation rates for different galaxy mass ranges, demonstrating the galaxy downsizing effect caused by less massive progenitors of less massive galaxies. The O and N abundances do not remain constant for different galaxy mass ranges, and the enrichment (and hence star formation) decreases with increasing galaxy stellar mass. We find evidence of the O enrichment for galaxies with stellar masses M-* > 10(11.0) (in units of M-circle dot), i.e. Delta(log (O/H)) similar to 0.10 and Delta (log (N/H)) similar to 0.28 from redshift 0.023 to 0.30. Based on the evolutionary schematic model of N/O ratios in Coziol et al., who proposed the scheme that the production of nitrogen is the consequence of a sequence of bursts in SFGs, we conclude that the nitrogen production is dominated by the intermediate-mass stars, which dominate the secondary synthesis in SFGs. However, for galaxies with M-* > 10(10.35) we find evidence of enhanced N/O abundance ratios, which are significantly above the secondary synthesis line. This suggests that outflows of massive stars, which deplete oxygen efficiently, are more important in massive galaxies. Finally, we find an excellent linear relation between M-* and log(N/O), indicating that the N/O abundance ratio is a good indicator of the stellar mass in a SFG and may be used as a standard candle for studying cosmology, if confirmed with further studies.