We report a new, rare detection of H I 21 cm absorption associated with a quasar (only six quasars are known at 1 < z < 2) toward J2339−5523 at z em = 1.3531, discovered through the MeerKAT ...Absorption Line Survey (MALS). The absorption profile is broad (∼400 km s −1 ), and the peak is redshifted by ∼200 km s −1 from z em . Interestingly, optical/far-UV spectra of the quasar from the Magellan-MIKE/HST-COS spectrographs do not show any absorption features associated with the 21 cm absorption, despite the coincident presence of the optical quasar and the radio core inferred from a flat-spectrum component with a flux density of ∼65 mJy at high frequencies (> 5 GHz). The simplest explanation would be that no large H I column ( N (H I ) > 10 17 cm −2 ) is present toward the radio core and the optical active galactic nucleus. Based on the joint optical and radio analysis of a heterogeneous sample of 16 quasars ( z median = 0.7) and 19 radio galaxies ( z median = 0.4) with H I 21 cm absorption detection and matched in 1.4 GHz luminosity ( L 1.4 GHz ), a consistent picture emerges according to which quasars primarily trace the gas in the inner circumnuclear disk and cocoon created by the interaction of the jet with interstellar medium. They (i.e., quasars) exhibit a L 1.4 GHz – Δ V null correlation and a frequent mismatch of the radio and optical spectral lines. The radio galaxies show no such correlation and likely trace the gas from the cocoon and the galaxy-wide interstellar medium outside the photoionization cone. The analysis presented here demonstrates the potential of radio spectroscopic observations to reveal the origin of the absorbing gas associated with active galactic nuclei that may be missed in optical observations.
We present a deep O iiiλλ4959,5007 image of the northern filamentary jet in the Crab Nebula taken with the 8.2-m Subaru telescope. Using this image and an image taken with the Kitt Peak National ...Observatory (KPNO) 4-m in 1988, we have computed proper motions for 35 locations in the jet. The results suggest that when compared to the main body of the remnant, the jet experienced less outward acceleration from the central pulsar's rapidly expanding synchrotron nebula. The jet's apparent expansion rate yields an undecelerated explosion date for the Crab Nebula of 1055 ± 24 CE, a date much closer to the appearance of the historic 1054 CE guest star than the 1120–1140 CE dates estimated in previous studies using filaments located within the remnant's main nebula. Our proper motion measurements suggest the jet likely formed during the 1054 supernova explosion and represents the remnant's highest velocity knots possibly associated with a suspected N–S bipolar outflow from the supernova explosion.
Autism spectrum disorders (ASDs) represent a formidable challenge for psychiatry and neuroscience because of their high prevalence, lifelong nature, complexity and substantial heterogeneity. Facing ...these obstacles requires large-scale multidisciplinary efforts. Although the field of genetics has pioneered data sharing for these reasons, neuroimaging had not kept pace. In response, we introduce the Autism Brain Imaging Data Exchange (ABIDE)-a grassroots consortium aggregating and openly sharing 1112 existing resting-state functional magnetic resonance imaging (R-fMRI) data sets with corresponding structural MRI and phenotypic information from 539 individuals with ASDs and 573 age-matched typical controls (TCs; 7-64 years) (http://fcon_1000.projects.nitrc.org/indi/abide/). Here, we present this resource and demonstrate its suitability for advancing knowledge of ASD neurobiology based on analyses of 360 male subjects with ASDs and 403 male age-matched TCs. We focused on whole-brain intrinsic functional connectivity and also survey a range of voxel-wise measures of intrinsic functional brain architecture. Whole-brain analyses reconciled seemingly disparate themes of both hypo- and hyperconnectivity in the ASD literature; both were detected, although hypoconnectivity dominated, particularly for corticocortical and interhemispheric functional connectivity. Exploratory analyses using an array of regional metrics of intrinsic brain function converged on common loci of dysfunction in ASDs (mid- and posterior insula and posterior cingulate cortex), and highlighted less commonly explored regions such as the thalamus. The survey of the ABIDE R-fMRI data sets provides unprecedented demonstrations of both replication and novel discovery. By pooling multiple international data sets, ABIDE is expected to accelerate the pace of discovery setting the stage for the next generation of ASD studies.
We present results from observations of supernova (SN) 1979C with the Newton X-Ray Multi-Mirror (XMM-Newton) mission in X-rays and in UV, archival X-ray, and Hubble Space Telescope (HST) data, and ...follow-up ground-based optical imaging. The XMM-Newton MOS spectrum shows the best-fit two- temperature thermal plasma emission characteristics of both the forward (kT sub(high) = 4.1 super(+) sub(-) super(7) sub(2) super(6) sub(.4) keV) and reverse shock (kT sub(high) = 0.79 super(+) sub(0) super(0) sub(.) super(.) sub(1) super(2) sub(7) super(4) keV) with no intrinsic absorption. The long-term X-ray light curve, constructed from all X-ray data available, reveals that SN 1979C is still radiating at a flux level similar to that detected by ROSAT in 1995, showing no sign of a decline over the last 6 years, some 16-23 yr after its outburst. The high inferred X-ray luminosity (L sub(0.3-2) = 8 x 10 super(38) ergs s super(-1)) is caused by the interaction of the SN shock with dense circumstellar matter, likely deposited by a strong stellar wind from the progenitor with a high mass-loss rate of M - 1.5 x 10 super(-4) M sub( )yr super(-1) (v sub(w)/10 km s super(-1)). The X-ray data support a strongly decelerated shock and show a mass-loss rate history that is consistent with a constant progenitor mass-loss rate and wind velocity over the past 16,000 yr in the stellar evolution of the progenitor. We find a best-fit circumstellar medium (CSM) density profile of r sub(cms) 8 r super(-s) with index s 1.7 and high CSM densities ( 10 super(4) cm super(-3)) out to large radii from the site of the explosion (r 4 x 10 super(17) cm). Using XMM-Newton Optical Monitor data, we further detect a pointlike optical/UV source consistent with the position of SN 1979C, with B-, U-, and UVW1-band luminosities of 5, 7, and 9 x 10 super(36) ergs s super(-1), respectively. The young stellar cluster in the vicinity of the SN, as imaged by the HST and follow-up ground-based optical imaging, can only provide a fraction of the total observed flux, so that a significant contribution to the output likely arises from the strong interaction of SN 1979C with dense CSM.
ABSTRACT
The intergalactic medium (IGM) acts like a calorimeter recording energy injection by cosmic structure formation, shocks and photoheating from stars and active galactic nuclei. It was ...recently proposed that spatially inhomogeneous TeV-blazars could significantly heat up the underdense IGM, resulting in patches of both cold and warm IGM around z ≃ 2−3. The goal of this study is to compare predictions of different blazar heating models with recent observations of the IGM. We perform a set of cosmological simulations and carefully compute mock observables of the Lyman-α (Lyα) forest. We perform a detailed assessment of different systematic uncertainties which typically impact this type of observables and find that they are smaller than the differences between our models. We find that our inhomogeneous blazar heating model is in good agreement with the Lyα line properties and the rescaled flux probability distribution function at high redshift (2.5 < z < 3) but that our blazar heating models are challenged by lower redshift data (2 < z < 2.5). Our results could be explained by HeII reionization although state-of-the-art models fall short on providing enough heating to the low-density IGM, thus motivating further radiative transfer studies of inhomogeneous HeII reionization. If blazars are indeed hosted by group-mass haloes of $2\times 10^{13}\, \rm {M}_\odot$, a later onset of blazar heating in comparison with previous models would be favoured, which could bring our findings here in agreement with the evidence of blazar heating from local gamma-ray observations.
Food systems are at the center of a brewing storm consisting of a rapidly changing climate, rising hunger and malnutrition, and significant social inequities. At the same time, there are vast ...opportunities to ensure that food systems produce healthy and safe food in equitable ways that promote environmental sustainability, especially if the world can come together at the UN Food Systems Summit in late 2021 and make strong and binding commitments toward food system transformation. The NIH-funded Nutrition Obesity Research Center at Harvard and the Harvard Medical School Division of Nutrition held their 22nd annual Harvard Nutrition Obesity Symposium entitled “Global Food Systems and Sustainable Nutrition in the 21st Century” in June 2021. This article presents a synthesis of this symposium and highlights the importance of food systems to addressing the burden of malnutrition and noncommunicable diseases, climate change, and the related economic and social inequities. Transformation of food systems is possible, and the nutrition and health communities have a significant role to play in this transformative process.
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Short bowel syndrome (SBS) results from significant intestinal loss and is characterized by insufficient absorption of nutrients and fluids. Preclinical large animal SBS models typically require ...parenteral nutrition (PN) support and may not be appropriate for studying interventions to improve intestinal absorption or adaptation. Here, we describe the development of a porcine SBS model that does not require PN support.
Eight male Yorkshire piglets underwent either a 75% or 90% jejunoileal resection (n = 5) or no resection (n = 3). Continuous enteral nutrition (EN) was provided via a gastrostomy tube. The final SBS model consisted of a 75% resection and nutrition provided via combination EN (60%) and per oral pig chow (40%). Body weight and concentration of fat-soluble vitamins were assessed on postoperative days (POD) 7, 14, and 21. For assessing fat malabsorption, the coefficient of fat absorption (CFA) was calculated following a 72-h stool collection.
Resected animals had decreased weight gain compared to unresected controls (POD21 + 8.3% versus +28.8%, P = 0.048). Vitamin D concentration was significantly lower in resected animals compared to controls on POD 7, POD 14, and POD 21. Serum vitamin E concentration was also lower on POD 21. Resected animals developed fat malabsorption with lower CFA (76.5% versus 95.3%, P = 0.014).
We describe the development of a porcine SBS model that does not require PN support. Piglets in this model gain less weight, demonstrate fat malabsorption, and develop fat-soluble vitamin deficiencies. This model will benefit investigations of intestinal absorption or adaptation while potentially decreasing costs and confounding complications related to PN administration.
II Zwicky 23 and Family Wehner, E.H.; Gallagher, J.S.; Rudie, G.C. ...
Groups of Galaxies in the Nearby Universe
Book Chapter
II Zwicky 23 (UGC 3179) is a luminous (MB ~ −21) nearby compact narrow emission line st arburst galaxy with blue optical colors and strong emission lines. We present a photometric and morphological ...study of II Zw 23 and its interacting companions using data obtained with the WIYN 3.5-m telescope in Kitt Peak, Arizona. II Zwicky 23 has a highly disturbed outer structure with long trails of debris that may be feeding tidal dwarfs.
Molecular markers based upon a novel lettuce LTR retrotransposon and the nucleotide binding site-leucine-rich repeat (NBS-LRR) family of disease resistance-associated genes have been combined with ...AFLP markers to generate a 458 locus genetic linkage map for lettuce. A total of 187 retrotransposon-specific SSAP markers, 29 NBS-LRR markers and 242 AFLP markers were mapped in an F₂ population, derived from an interspecific cross between a Lactuca sativa cultivar commonly used in Europe and a wild Lactuca serriola isolate from Northern Europe. The cross has been designed to aid efforts to assess gene flow from cultivated lettuce into the wild in the perspective of genetic modification biosafety. The markers were mapped in nine major and one minor linkage groups spanning 1,266.1 cM, with an average distance of 2.8 cM between adjacent mapped markers. The markers are well distributed throughout the lettuce genome, with limited clustering of different marker types. Seventy-seven of the AFLP markers have been mapped previously and cross-comparison shows that the map from this study corresponds well with the previous linkage map.
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