MELON: NeRF with Unposed Images Using Equivalence Class Estimation

Neural radiance fields enable novel-view synthesis and scene reconstruction with photorealistic quality from a few images, but require known and accurate camera poses. Conventional pose estimation algorithms fail on smooth or self-similar scenes, while methods performing inverse rendering from unposed views require a rough initialization of the camera orientations. The main difficulty of pose estimation lies in real-life objects being almost invariant under certain transformations, making the photometric distance between rendered views non-convex with respect to the camera parameters. Using an equivalence relation that matches the distribution of local minima in camera space, we reduce this space to its quotient set, in which pose estimation becomes a more convex problem. Using a neural-network to regularize pose estimation, we demonstrate that our method - MELON - can reconstruct a neural radiance field from unposed images with state-of-the-art accuracy while requiring ten times fewer views than adversarial approaches

Heterogeneous reconstruction of deformable atomic models in Cryo-EM

Cryogenic electron microscopy (cryo-EM) provides a unique opportunity to study the structural heterogeneity of biomolecules. Being able to explain this heterogeneity with atomic models would help our understanding of their functional mechanisms but the size and ruggedness of the structural space (the space of atomic 3D cartesian coordinates) presents an immense challenge. Here, we describe a heterogeneous reconstruction method based on an atomistic representation whose deformation is reduced to a handful of collective motions through normal mode analysis. Our implementation uses an autoencoder. The encoder jointly estimates the amplitude of motion along the normal modes and the 2D shift between the center of the image and the center of the molecule . The physics-based decoder aggregates a representation of the heterogeneity readily interpretable at the atomic level. We illustrate our method on 3 synthetic datasets corresponding to different distributions along a simulated trajectory of adenylate kinase transitioning from its open to its closed structures. We show for each distribution that our approach is able to recapitulate the intermediate atomic models with atomic-level accuracy.Comment: 8 pages, 1 figur

Generative Novel View Synthesis with 3D-Aware Diffusion Models

We present a diffusion-based model for 3D-aware generative novel view synthesis from as few as a single input image. Our model samples from the distribution of possible renderings consistent with the input and, even in the presence of ambiguity, is capable of rendering diverse and plausible novel views. To achieve this, our method makes use of existing 2D diffusion backbones but, crucially, incorporates geometry priors in the form of a 3D feature volume. This latent feature field captures the distribution over possible scene representations and improves our method's ability to generate view-consistent novel renderings. In addition to generating novel views, our method has the ability to autoregressively synthesize 3D-consistent sequences. We demonstrate state-of-the-art results on synthetic renderings and room-scale scenes; we also show compelling results for challenging, real-world objects.Comment: Project page: https://nvlabs.github.io/genv

Clastic patterned ground in Lomonosov crater, Mars: examining fracture controlled formation mechanisms

The area surrounding Lomonosov crater on Mars has a high density of seemingly organised boulder patterns. These form seemingly sorted polygons and stripes within kilometre scale blockfields, patches of boulder strewn ground which are common across the Martian high latitudes. Several hypotheses have been suggested to explain the formation of clastic patterned ground on Mars. It has been proposed that these structures could have formed through freeze-thaw sorting, or conversely by the interaction of boulders with underlying fracture polygons. In this investigation a series of sites were examined to evaluate whether boulder patterns appear to be controlled by the distribution of underlying fractures and test the fracture control hypotheses for their formation. It was decided to focus on this suite of mechanisms as they are characterised by a clear morphological relationship, namely the presence of an underlying fracture network which can easily be evaluated over a large area. It was found that in the majority of examples at these sites did not exhibit fracture control. Although fractures were present at many sites there were very few sites where the fracture network appeared to be controlling the boulder distribution. In general these were not the sites with the best examples of organization, suggesting that the fracture control mechanisms are not the dominant geomorphic process organising the boulders in this area

The Molecular ISM in the Super Star Clusters of the Starburst NGC 253

We present submillimeter spectra of the (proto-)super star cluster (SSC) candidates in the starbursting center of the nearby galaxy NGC 253 identified by Leroy et al. (2018). The 2.5pc resolution of our ALMA cycle 3 observations approach the size of the SSCs and allows the study of physical and chemical properties of the molecular gas in these sources. In the 14 SSC sources and in the frequency ranges 342.0-345.8 GHz and 353.9-357.7 GHz we detect 55 lines belonging to 19 different chemical species. The SSCs differ significantly in chemical complexity, with the richest clusters showing 19 species and the least complex showing 4 species. We detect HCN isotopologues and isomers (H$^{13}$CN, HC$^{15}$N, H$^{15}$NC), abundant HC$_3$N, SO and S$^{18}$O, SO$_2$, and H$_2$CS. The gas ratios CO/HCN, CO/HCO$^+$ are low, ~1-10, implying high dense gas fractions in the SSCs. Line ratio analyses suggests chemistry consistent with photon-dominated regions and mechanical heating. None of the SSCs near the galaxy center show line ratios that imply an X-ray dominated region, suggesting that heating by any (still unknown) AGN does not play a major role. The gas temperatures are high in most sources, with an average rotational temperature of ~130 K in SO$_2$. The widespread existence of vibrationally excited HCN and HC$_3$N transitions implies strong IR radiation fields, potentially trapped by a greenhouse effect due to high continuum opacities.Comment: 20 pages, 4 figures, 6 tables; accepted for publication in the Astrophysical Journa

The Molecular Outflow in NGC 253 at a Resolution of Two Parsecs

We present 0.'' 15 (similar to 2.5 pc) resolution ALMA CO(3-2) observations of the starbursting center in NGC 253. Together with archival ALMA CO(1-0) and CO(2-1) data, we decompose the emission into disk and nondisk components. We find similar to 7%-16% of the CO luminosity to be associated with the nondisk component (1.2-4.2 x 10(7) K km s(-1) pc(2)). The total molecular gas mass in the center of NGC 253 is similar to 3.6 x 10(8) M-circle dot with similar to 0.5 x 10(8) M-circle dot (similar to 15%) in the nondisk component. These measurements are consistent across independent mass estimates through three CO transitions. The high-resolution CO(3-2) observations allow us to identify the molecular outflow within the nondisk gas. Using a starburst conversion factor, we estimate the deprojected molecular mass outflow rate, kinetic energy, and momentum in the starburst of NGC 253. The deprojected molecular mass outflow rate is in the range of similar to 14-39 M-circle dot yr(-1) with an uncertainty of 0.4 dex. The large spread arises due to different interpretations of the kinematics of the observed gas while the errors are due to unknown geometry. The majority of this outflow rate is contributed by distinct outflows perpendicular to the disk, with a significant contribution by diffuse molecular gas. This results in a mass-loading factor eta = (M) over dot(out)/(M) over dot(SFR) in the range eta similar to 8-20 for gas ejected out to similar to 300 pc. We find the kinetic energy of the outflow to be similar to 2.5-4.5 x 10(54) erg and a typical error of similar to 0.8 dex, which is similar to 0.1% of the total or similar to 8% of the kinetic energy supplied by the starburst. The outflow momentum is 4.8-8.7 x 10(8) M-circle dot km s(-1) (similar to 0.5 dex error) or similar to 2.5%-4% of the kinetic momentum released into the ISM by the feedback. The unknown outflow geometry and launching sites are the primary sources of uncertainty in this study.Peer reviewe

The turbulent gas structure in the centers of NGC253 and the Milky Way

We compare molecular gas properties in the starbursting center of NGC253 and the Milky Way Galactic Center (GC) on scales of ~1-100 pc using dendograms and resolution-, area- and noise-matched datasets in CO (1-0) and CO (3-2). We find that the size-line width relations in NGC253 and the GC have similar slope, but NGC253 has larger line widths by factors of ~2-3. The $\sigma^2/R$ dependency on column density shows that, in the GC, on scales of 10-100 pc the kinematics of gas over $N>3\times10^{21}$ cm$^{-2}$ are compatible with gravitationally bound structures. In NGC253 this is only the case for column densities $N>3\times10^{22}$ cm$^{-2}$. The increased line widths in NGC253 originate in the lower column density gas. This high-velocity dispersion, not gravitationally self-bound gas is likely in transient structures created by the combination of high average densities and feedback in the starburst. The high densities turns the gas molecular throughout the volume of the starburst, and the injection of energy and momentum by feedback significantly increases the velocity dispersion at a given spatial scale over what is observed in the GC.Comment: 13 pages, 3 figures, 4 tables; accepted for publication in the Astrophysical Journa

Sudden Cardiac Death in Heart Failure: A 20-Year Perspective From a Mediterranean Cohort

Background: The prediction of sudden cardiac death (SCD) in heart failure (HF) remains an unmet need. The aim of our study was to assess the prevalence of SCD over 20 years in outpatients with HF managed in a Mediterranean multidisciplinary HF Clinic, and to compare the proportion of SCD (SCD/all-cause death) to the expected proportional occurrence based on the validated Seattle Proportional Risk Model (SPRM) score. Methods and results: This prospective observational registry study included 2772 outpatients with HF admitted between August 2001 and May 2021. Patients were included when the cause of death was known and SPRM score was available. Over the 20-year study period, 1351 patients (48.7%) died during a median follow-up period of 3.8 years (interquartile range 1.6-7.6). Among these patients, the proportion of SCD out of the total of deaths was 13.6%, whereas the predicted by SPRM was 39.6%. This lower proportion of SCD was observed independently of left ventricular ejection fraction, ischemic etiology, and the presence of an implantable cardiac defibrillator. Conclusions: In a Mediterranean cohort of outpatients with HF, the proportion of SCD was lower than expected based on the SPRM score. Future studies should investigate to what extend epidemiological and guideline-directed medical therapy patterns influence SCD

Outflows from Super Star Clusters in the Central Starburst of NGC253

Young massive clusters play an important role in the evolution of their host galaxies, and feedback from the high-mass stars in these clusters can have profound effects on the surrounding interstellar medium. The nuclear starburst in the nearby galaxy NGC253 at a distance of 3.5 Mpc is a key laboratory in which to study star formation in an extreme environment. Previous high resolution (1.9 pc) dust continuum observations from ALMA discovered 14 compact, massive super star clusters (SSCs) still in formation. We present here ALMA data at 350 GHz with 28 milliarcsecond (0.5 pc) resolution. We detect blueshifted absorption and redshifted emission (P-Cygni profiles) towards three of these SSCs in multiple lines, including CS 7$-$6 and H$^{13}$CN 4$-$3, which represents direct evidence for previously unobserved outflows. The mass contained in these outflows is a significant fraction of the cluster gas masses, which suggests we are witnessing a short but important phase. Further evidence of this is the finding of a molecular shell around the only SSC visible at near-IR wavelengths. We model the P-Cygni line profiles to constrain the outflow geometry, finding that the outflows must be nearly spherical. Through a comparison of the outflow properties with predictions from simulations, we find that none of the available mechanisms completely explains the observations, although dust-reprocessed radiation pressure and O star stellar winds are the most likely candidates. The observed outflows will have a very substantial effect on the clusters' evolution and star formation efficiency.Comment: Accepted to Ap

Protocol of a prospective multicenter study on comorbidity impact on multiple sclerosis and antibody-mediated diseases of the central nervous system (COMMIT)

Comorbidities in patients with multiple sclerosis (MS) and antibody-mediated diseases of the central nervous system (CNS) including neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein (MOG)-antibody-associated disease (MOGAD) are common and may influence the course of their neurological disease. Comorbidity may contribute to neuronal injury and therefore limit recovery from attacks, accelerate disease progression, and increase disability. This study aims to explore the impact of comorbidity, particularly vascular comorbidity, and related risk factors on clinical and paraclinical parameters of MS, NMOSD and MOGAD. We propose COMMIT, a prospective multicenter study with longitudinal follow-up of patients with MS, NMOSD, and MOGAD, with or without comorbidities, as well as healthy subjects as controls. Subjects will be stratified by age, sex and ethnicity. In consecutive samples we will analyze levels of inflammation and neurodegeneration markers in both fluid and cellular compartments of the peripheral blood and cerebrospinal fluid (CSF) using multiple state-of-the-art technologies, including untargeted proteomics and targeted ultrasensitive ELISA assays and quantitative reverse transcription polymerase chain reaction (RT-qPCR) as well as high-dimensional single-cell technologies i.e., mass cytometry and single-cell RNA sequencing. Algorithm-based data analyses will be used to unravel the relationship between these markers, optical coherence tomography (OCT) and magnetic resonance imaging (MRI), and clinical outcomes including frequency and severity of relapses, long-term disability, and quality of life. The goal is to evaluate the impact of comorbidities on MS, NMOSD, and MOGAD which may lead to development of treatment approaches to improve outcomes of inflammatory demyelinating diseases of the CNS