Compositional Analysis of Lignocellulosic Feedstocks. 2. Method Uncertainties

The most common procedures for characterizing the chemical components of lignocellulosic feedstocks use a two-stage sulfuric acid hydrolysis to fractionate biomass for gravimetric and instrumental analyses. The uncertainty (i.e., dispersion of values from repeated measurement) in the primary data is of general interest to those with technical or financial interests in biomass conversion technology. The composition of a homogenized corn stover feedstock (154 replicate samples in 13 batches, by 7 analysts in 2 laboratories) was measured along with a National Institute of Standards and Technology (NIST) reference sugar cane bagasse, as a control, using this laboratory's suite of laboratory analytical procedures (LAPs). The uncertainty was evaluated by the statistical analysis of these data and is reported as the standard deviation of each component measurement. Censored and uncensored versions of these data sets are reported, as evidence was found for intermittent instrumental and equipment problems. The censored data are believed to represent the “best case” results of these analyses, whereas the uncensored data show how small method changes can strongly affect the uncertainties of these empirical methods. Relative standard deviations (RSD) of 1−3% are reported for glucan, xylan, lignin, extractives, and total component closure with the other minor components showing 4−10% RSD. The standard deviations seen with the corn stover and NIST bagasse materials were similar, which suggests that the uncertainties reported here are due more to the analytical method used than to the specific feedstock type being analyzed

A Spectroscopic Search for Leaking Lyman Continuum at Zeta Approximately 0.7

We present the results of rest-frame, UV slitless spectroscopic observations of a sample of 32 z approx. 0.7 Lyman Break Galaxy (LBG) analogs in the COSMOS field. The spectroscopic search was performed with the Solar Blind Channel (SBC) on HST. While we find no direct detections of the Lyman Continuum we achieve individual limits (3sigma) of the observed non-ionizing UV to Lyman continuum flux density ratios, f(sub nu)(1500A)/f(sub nu)(830A) of 20 to 204 (median of 73.5) and 378.7 for the stack. Assuming an intrinsic Lyman Break of 3.4 and an optical depth of Lyman continuum photons along the line of sight to the galaxy of 85% we report an upper limit for the relative escape fraction in individual galaxies of 0.02 - 0.19 and a stacked 3sigma upper limit of 0.01. We find no indication of a relative escape fraction near unity as seen in some LBGs at z approx. 3. Our UV spectra achieve the deepest limits to date at any redshift on the escape fraction in individual sources. The contrast between these z approx. 0.7 low escape fraction LBG analogs with z approx. 3 LBGs suggests that either the processes conducive to high f(sub esc) are not being selected for in the z less than or approx.1 samples or the average escape fraction is decreasing from z approx. 3 to z approx. 1. We discuss possible mechanisms which could affect the escape of Lyman continuum photon

Star-forming Blue ETGs in Two Newly Discovered Galaxy Overdensities in the HUDF at z=1.84 and 1.9: Unveiling the Progenitors of Passive ETGs in Cluster Cores

We present the discovery of two galaxy overdensities in the Hubble Space Telescope UDF: a proto-cluster, HUDFJ0332.4-2746.6 at z=1.84 ± 0.01, and a group, HUDFJ0332.5-2747.3 at z=1.90 ± 0.01. Assuming viralization, the velocity dispersion of HUDFJ0332.4-2746.6 implies a mass of M_(200) = (2.2 ± 1.8) x 10^(14) M_☉, consistent with the lack of extended X-ray emission. Neither overdensity shows evidence of a red sequence. About $50\%$ of their members show interactions and/or disturbed morphologies, which are signatures of merger remnants or disk instability. Most of their ETGs have blue colors and show recent star formation. These observations reveal for the first time large fractions of spectroscopically confirmed star-forming blue ETGs in proto-clusters at ≈ z. These star-forming ETGs are most likely among the progenitors of the quiescent population in clusters at more recent epochs. Their mass–size relation is consistent with that of passive ETGs in clusters at z ~ 0.7-1.5. If these galaxies are the progenitors of cluster ETGs at these lower redshifts, their size would evolve according to a similar mass-size relation. It is noteworthy that quiescent ETGs in clusters at z = 1.8-2 also do not show any significant size evolution over this redshift range, contrary to field ETGs. The ETG fraction is ≾50%, compared to the typical quiescent ETG fraction of ≈80% in cluster cores at z < 1. The fraction, masses, and colors of the newly discovered ETGs imply that other cluster ETGs will be formed/accreted at a later time

A Deep HST Search for Escaping Lyman Continuum Flux at z~1.3: Evidence for an Evolving Ionizing Emissivity

We have obtained deep Hubble Space Telescope far-UV images of 15 starburst galaxies at z~1.3 in the GOODS fields to search for escaping Lyman continuum photons. These are the deepest far-UV images m_{AB}=28.7, 3\sigma, 1" diameter) over this large an area (4.83 arcmin^2) and provide the best escape fraction constraints for any galaxy at any redshift. We do not detect any individual galaxies, with 3\sigma limits to the Lyman Continuum (~700 \AA) flux 50--149 times fainter (in f_nu) than the rest-frame UV (1500 \AA) continuum fluxes. Correcting for the mean IGM attenuation (factor ~2), as well as an intrinsic stellar Lyman Break (~3), these limits translate to relative escape fraction limits of f_{esc,rel}<[0.03,0.21]. The stacked limit is f_{esc,rel}(3\sigma)<0.02. We use a Monte Carlo simulation to properly account for the expected distribution of IGM opacities. When including constraints from previous surveys at z~1.3 we find that, at the 95% confidence level, no more than 8% of star--forming galaxies at z~1.3 can have relative escape fractions greater than 0.50. Alternatively, if the majority of galaxies have low, but non-zero, escaping Lyman Continuum, the escape fraction can not be more than 0.04. Both the stacked limits, and the limits from the Monte Carlo simulation suggest that the average ionizing emissivity (relative to non-ionizing UV emissivity) at z~1.3 is significantly lower than has been observed in Lyman Break Galaxies (LBGs) at z~3. If the ionizing emissivity of star-forming galaxies is in fact increasing with redshift, it would help to explain the high photoionization rates seen in the IGM at z>4 and reionization of the intergalactic medium at z>6. [Abridged]Comment: Submitted to ApJ (Nov. 6) Comments Welcome. 11 pages, 8 figure

Baseline characteristics of patients in the Reduction of Events with Darbepoetin alfa in Heart Failure trial (RED-HF)

Aims: This report describes the baseline characteristics of patients in the Reduction of Events with Darbepoetin alfa in Heart Failure trial (RED-HF) which is testing the hypothesis that anaemia correction with darbepoetin alfa will reduce the composite endpoint of death from any cause or hospital admission for worsening heart failure, and improve other outcomes. Methods and results: Key demographic, clinical, and laboratory findings, along with baseline treatment, are reported and compared with those of patients in other recent clinical trials in heart failure. Compared with other recent trials, RED-HF enrolled more elderly [mean age 70 (SD 11.4) years], female (41%), and black (9%) patients. RED-HF patients more often had diabetes (46%) and renal impairment (72% had an estimated glomerular filtration rate < 60 mL/min/1.73 m2). Patients in RED-HF had heart failure of longer duration [5.3 (5.4) years], worse NYHA class (35% II, 63% III, and 2% IV), and more signs of congestion. Mean EF was 30% (6.8%). RED-HF patients were well treated at randomization, and pharmacological therapy at baseline was broadly similar to that of other recent trials, taking account of study-specific inclusion/exclusion criteria. Median (interquartile range) haemoglobin at baseline was 112 (106–117) g/L. Conclusion: The anaemic patients enrolled in RED-HF were older, moderately to markedly symptomatic, and had extensive co-morbidity

A spatially resolved analysis of star-formation burstiness by comparing UV and Hα\alpha in galaxies at z∼\sim1 with UVCANDELS

The UltraViolet imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey Fields (UVCANDELS) program provides HST/UVIS F275W imaging for four CANDELS fields. We combine this UV imaging with existing HST/near-IR grism spectroscopy from 3D-HST+AGHAST to directly compare the resolved rest-frame UV and H$\alpha$ emission for a sample of 979 galaxies at $0.7<z<1.5$ spanning a range in stellar mass of $10^{8-11.5}~M_\odot$. Since both rest-UV and H$\alpha$ are sensitive to on-going star-formation but over different timescales, their resolved comparison allows us to infer the burstiness in star-formation as a function of galaxy structural parameters. We generate homogenized maps of rest-UV and H$\alpha$ emission for all galaxies in our sample and stack them to compute the average UV-to-H$\alpha$ luminosity ratio as a function of galactocentric radius. We find that galaxies below stellar mass of $\sim10^{9.5}~M_\odot$, at all radii, have a UV-to-H$\alpha$ ratio higher than the equilibrium value expected from constant star-formation, indicating a significant contribution from bursty star-formation. Even for galaxies with stellar mass $\gtrsim10^{9.5} M_\odot$, the UV-to-H$\alpha$ ratio is elevated towards in their outskirts ($R/R_{eff}>1.5$), suggesting that bursty star-formation is likely prevalent in the outskirts of even the most massive galaxies but is likely over-shadowed by their brighter cores. Furthermore, we present the UV-to-H$\alpha$ ratio as a function of galaxy surface brightness, a proxy for stellar mass surface density, and find that regions below $\sim10^8~M_\odot~kpc^{-2}$ are consistent with bursty star-formation, regardless of their galaxy stellar mass, potentially suggesting that local star-formation is independent of global galaxy properties at the smallest scales.Comment: 19 pages, 8 figures; submitted to Ap

Galaxy Zoo: quantitative visual morphological classifications for 48 000 galaxies from CANDELS

We present quantified visual morphologies of approximately 48 000 galaxies observed in three Hubble Space Telescope legacy fields by the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and classified by participants in the Galaxy Zoo project. 90 per cent of galaxies have z ≤ 3 and are observed in rest-frame optical wavelengths by CANDELS. Each galaxy received an average of 40 independent classifications, which we combine into detailed morphological information on galaxy features such as clumpiness, bar instabilities, spiral structure, and merger and tidal signatures. We apply a consensus-based classifier weighting method that preserves classifier independence while effectively down-weighting significantly outlying classifications. After analysing the effect of varying image depth on reported classifications, we also provide depth-corrected classifications which both preserve the information in the deepest observations and also enable the use of classifications at comparable depths across the full survey. Comparing the Galaxy Zoo classifications to previous classifications of the same galaxies shows very good agreement; for some applications, the high number of independent classifications provided by Galaxy Zoo provides an advantage in selecting galaxies with a particular morphological profile, while in others the combination of Galaxy Zoo with other classifications is a more promising approach than using any one method alone. We combine the Galaxy Zoo classifications of ‘smooth’ galaxies with parametric morphologies to select a sample of featureless discs at 1 ≤ z ≤ 3, which may represent a dynamically warmer progenitor population to the settled disc galaxies seen at later epochs

Understanding the circumgalactic medium is critical for understanding galaxy evolution

Galaxies evolve under the influence of gas flows between their interstellar medium and their surrounding gaseous halos known as the circumgalactic medium (CGM). The CGM is a major reservoir of galactic baryons and metals, and plays a key role in the long cycles of accretion, feedback, and recycling of gas that drive star formation. In order to fully understand the physical processes at work within galaxies, it is therefore essential to have a firm understanding of the composition, structure, kinematics, thermodynamics, and evolution of the CGM. In this white paper we outline connections between the CGM and galactic star formation histories, internal kinematics, chemical evolution, quenching, satellite evolution, dark matter halo occupation, and the reionization of the larger-scale intergalactic medium in light of the advances that will be made on these topics in the 2020s. We argue that, in the next decade, fundamental progress on all of these major issues depends critically on improved empirical characterization and theoretical understanding of the CGM. In particular, we discuss how future advances in spatially-resolved CGM observations at high spectral resolution, broader characterization of the CGM across galaxy mass and redshift, and expected breakthroughs in cosmological hydrodynamic simulations will help resolve these major problems in galaxy evolution.Comment: Astro2020 Decadal Science White Pape