We analyze the multifrequency radio spectral properties of 41 6 GHz-detected Atacama Large Millimeter/submillimeter Array (ALMA)-identified, submillimeter galaxies (SMGs), observed at 610 MHz, 1.4 ...GHz, and 6 GHz with the Giant Metrewave Radio Telescope and the Very Large Array. Combining high-resolution (∼0 5) 6 GHz radio and ALMA 870 m imaging (tracing rest frame ∼20 GHz, and ∼250 m dust continuum), we study the far-infrared/radio correlation via the logarithmic flux ratio qIR, measuring for our sample. We show that the high-frequency radio sizes of SMGs are ∼1.9 0.4× (∼2-3 kpc) larger than those of the cool dust emission, and find evidence for a subset of our sources being extended on ∼10 kpc scales at 1.4 GHz. By combining radio flux densities measured at three frequencies, we can move beyond simple linear fits to the radio spectra of high-redshift star-forming galaxies, and search for spectral curvature, which has been observed in local starburst galaxies. At least a quarter (10/41) of our sample shows evidence of a spectral break, with a median , but -a high-frequency flux deficit relative to simple extrapolations from the low-frequency data. We explore this result within this subset of sources in the context of age-related synchrotron losses, showing that a combination of weak magnetic fields (B ∼ 35 G) and young ages (tSB ∼ 40-80 Myr) for the central starburst can reproduce the observed spectral break. Assuming these represent evolved (but ongoing) starbursts, and we are observing these systems roughly halfway through their current episode of star formation, this implies starburst durations of 100 Myr, in reasonable agreement with estimates derived via gas depletion timescales.
ABSTRACT
We determine the Milky Way (MW) mass profile inferred from fitting physically motivated models to the Gaia DR2 Galactic rotation curve and other data. Using various hydrodynamical ...simulations of MW-mass haloes, we show that the presence of baryons induces a contraction of the dark matter (DM) distribution in the inner regions, r ≲ 20 kpc. We provide an analytic expression that relates the baryonic distribution to the change in the DM halo profile. For our galaxy, the contraction increases the enclosed DM halo mass by factors of roughly 1.3, 2, and 4 at radial distances of 20, 8, and 1 kpc, respectively compared to an uncontracted halo. Ignoring this contraction results in systematic biases in the inferred halo mass and concentration. We provide a best-fitting contracted NFW halo model to the MW rotation curve that matches the data very well.1 The best-fit has a DM halo mass, $M_{200}^{\rm DM}=0.97_{-0.19}^{+0.24}\times 10^{12}\,\mathrm{M}_\odot$, and concentration before baryon contraction of $9.4_{-2.6}^{+1.9}$, which lie close to the median halo mass–concentration relation predicted in ΛCDM. The inferred total mass, $M_{200}^{\rm total}=1.08_{-0.14}^{+0.20} \times 10^{12}\,\mathrm{M}_\odot$, is in good agreement with recent measurements. The model gives an MW stellar mass of $5.04_{-0.52}^{+0.43}\times 10^{10}\,\mathrm{M}_\odot$ and infers that the DM density at the Solar position is $\rho _{\odot }^{\rm DM}=8.8_{-0.5}^{+0.5}\times 10^{-3}\,\mathrm{M}_\odot \,\mathrm{pc}^{-3}\equiv 0.33_{-0.02}^{+0.02}\,\rm {GeV}\,\rm {cm}^{-3}$. The rotation curve data can also be fitted with an uncontracted NFW halo model, but with very different DM and stellar parameters. The observations prefer the physically motivated contracted NFW halo, but the measurement uncertainties are too large to rule out the uncontracted NFW halo.
Fluorotelomer ethoxylates are reported in indoor dust and industrial wastewater.
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Concerns regarding the persistence, bioaccumulation behaviour, and toxicity of perfluorooctanoic acid ...and perfluorooctane sulfonic acid have resulted in the creation of thousands of replacement perfluoroalkyl substances (PFAS). This study reports on the discovery of fluorotelomer ethoxylates (FTEO) in indoor dust (9/15 samples), and industrial effluents (14/37 samples) using gas chromatographic cyclic ion mobility mass spectrometry (GC-cIMS). By filtering the detected unknowns by mass and collision-cross section, a series of FTEO homologues were revealed with the formula F-(CF2)n(C2H4O)xH, where n = 6,8,10, and x = 4–12. The highest concentrations were observed in samples collected from healthcare facilities, consistent with the potential use of these compounds in anti-fog products, sprays used to prevent condensation on eyeglasses. FTEOs were also detected in c. 40 % of industrial effluent samples, with the highest concentrations in electroplating facilities, manufacturers of cosmetics and personal care products, and linen cleaning services for healthcare and work uniforms. These results suggest that FTEOs may well be widespread pollutants that are more persistent than previously thought, underlining the need for further study of their occurrence and potential impact to human health and the environment.
Since the isolation of soil organic matter in 1786, tens of thousands of publications have searched for its structure. Nuclear magnetic resonance (NMR) spectroscopy has played a critical role in ...defining soil organic matter but traditional approaches remove key information such as the distribution of components at the soil–water interface and conformational information. Here a novel form of NMR with capabilities to study all physical phases termed Comprehensive Multiphase NMR, is applied to analyze soil in its natural swollen-state. The key structural components in soil organic matter are identified to be largely composed of macromolecular inputs from degrading biomass. Polar lipid heads and carbohydrates dominate the soil–water interface while lignin and microbes are arranged in a more hydrophobic interior. Lignin domains cannot be penetrated by aqueous solvents even at extreme pH indicating they are the most hydrophobic environment in soil and are ideal for sequestering hydrophobic contaminants. Here, for the first time, a complete range of physical states of a whole soil can be studied. This provides a more detailed understanding of soil organic matter at the molecular level itself key to develop the most efficient soil remediation and agricultural techniques, and better predict carbon sequestration and climate change.
To assess the safety, tolerability, and biological activity of glial cell line-derived neurotrophic factor (GDNF) administered by an implanted intracerebroventricular (ICV) catheter and access port ...in advanced PD.
GDNF is a peptide that promotes survival of dopamine neurons. It improved 6-OHDA- or MPTP-induced behavioral deficits in rodents and monkeys.
A multicenter, randomized, double-blind, placebo-controlled, sequential cohort study compared the effects of monthly ICV administration of placebo and 25, 75, 150, 300, and 500 to 4,000 microg of GDNF in 50 subjects with PD for 8 months. An open-label study extended exposure up to an additional 20 months and maximum single doses of up to 4,000 microg in 16 subjects. Laboratory testing, adverse events (AE), and Unified Parkinson's Disease Rating Scale (UPDRS) scoring were obtained at 1- to 4-week intervals throughout the studies.
Twelve subjects received placebo and seven or eight subjects were assigned to each of the other GDNF dose groups. "On" and "off" total and motor UPDRS scores were not improved by GDNF at any dose. Nausea, anorexia, and vomiting were common hours to several days after injections of GDNF. Weight loss occurred in the majority of subjects receiving 75 microg or larger doses of GDNF. Paresthesias, often described as electric shocks (Lhermitte sign), were common in GDNF-treated subjects, were not dose related, and resolved on discontinuation of GDNF. Asymptomatic hyponatremia occurred in over half of subjects receiving 75 microg or larger doses of GDNF; it was symptomatic in several subjects. The open-label extension study had similar AE and lack of therapeutic efficacy.
GDNF administered by ICV injection is biologically active as evidenced by the spectrum of AE encountered in this study. GDNF did not improve parkinsonism, possibly because GDNF did not reach the target tissues--putamen and substantia nigra.
ABSTRACT Until recently, only a handful of dusty, star-forming galaxies (DSFGs) were known at z > 4, most of them significantly amplified by gravitational lensing. Here, we have increased the number ...of such DSFGs substantially, selecting galaxies from the uniquely wide 250, 350, and 500 m Herschel-ATLAS imaging survey on the basis of their extremely red far-infrared colors and faint 350 and 500 m flux densities, based on which, they are expected to be largely unlensed, luminous, rare, and very distant. The addition of ground-based continuum photometry at longer wavelengths from the James Clerk Maxwell Telescope and the Atacama Pathfinder Experiment allows us to identify the dust peak in their spectral energy distributions (SEDs), with which we can better constrain their redshifts. We select the SED templates that are best able to determine photometric redshifts using a sample of 69 high-redshift, lensed DSFGs, then perform checks to assess the impact of the CMB on our technique, and to quantify the systematic uncertainty associated with our photometric redshifts, = 0.14 (1 + z), using a sample of 25 galaxies with spectroscopic redshifts, each consistent with our color selection. For Herschel-selected ultrared galaxies with typical colors of S500/S250 ∼ 2.2 and S500/S350 ∼ 1.3 and flux densities, S500 ∼ 50 mJy, we determine a median redshift, , an interquartile redshift range, 3.30-4.27, with a median rest-frame 8-1000 m luminosity, , of 1.3 × 1013 L . A third of the galaxies lie at z > 4, suggesting a space density, z > 4, of 6 × 10−7 Mpc−3. Our sample contains the most luminous known star-forming galaxies, and the most overdense cluster of starbursting proto-ellipticals found to date.
Soil organic matter (SOM) constitutes more than two-thirds of terrestrial carbon stocks yet there are many uncertainties about the fate of soil carbon reserves with global environmental change. ...Moisture, altered nutrient cycles, species shifts, growing season length or rising temperatures may alter forest primary productivity and the proportions of above and belowground biomass entering soil. We investigated SOM composition using molecular-level techniques after 20 years of detrital input and removal treatment (DIRT) at the Harvard Forest. SOM biomarkers (solvent extraction, base hydrolysis and cupric(II) oxide oxidation) and nuclear magnetic resonance (NMR) spectroscopy were used to quantify changes in SOM composition and microbial activity and community composition was assessed using phospholipid fatty acid (PLFA) analysis. Doubling aboveground litter inputs decreased soil carbon content, increased the degradation of labile SOM and enhanced the sequestration of aliphatic compounds in soil. The exclusion of belowground inputs resulted in a decrease in root-derived components and enhanced the degradation of stable SOM components such as leaf-derived aliphatic structures (cutin). The DIRT manipulations resulted in soil microbial community shifts that were attributed to the accelerated processing of specific SOM components. These results collectively reveal that a detailed molecular-level characterization of SOM can provide information on SOM compositional changes and transformations after 20 years of input manipulation in a temperate forest.
We present detections at 850 ...m of the Lyman-break galaxy (LBG) population at z ... 3, 4, and 5 using data from the Submillimetre Common User Bolometer Array 2 Cosmology Legacy Survey in the United ...Kingdom Infrared Deep Sky Survey 'Ultra Deep Survey' field. We employ stacking to probe beneath the survey limit, measuring the average 850 ...m flux density of LBGs at z ... 3, 4, and 5 with typical ultraviolet luminosities of ... We measure 850 ...m flux densities of (0.25 ± 0.03), (0.41 ± 0.06), and (0.88 ± 0.23) mJy, respectively, finding that they contribute at most 20 per cent to the cosmic far-infrared (IR) background at 850 ...m. Fitting an appropriate range of spectral energy distributions to the z ~ 3, 4, and 5 LBG stacked 24-850 ...m fluxes, we derive IR luminosities of ... and star formation rates (SFRs) of ..., respectively. We find that the evolution in the IR luminosity density of LBGs is broadly consistent with model predictions for the expected contribution of luminous-to-ultraluminous IR galaxies at these epochs. We observe a positive correlation between stellar mass and IR luminosity and confirm that, for a fixed mass, the reddest LBGs (UV slope β ... 0) are redder due to dust extinction, with SFR(IR)/SFR(UV) increasing by about an order of magnitude over -2 < β < 0 with SFR(IR)/SFR(UV) ~ 20 for the reddest LBGs. Furthermore, the most massive LBGs tend to have higher obscured-to-unobscured ratios, hinting at a variation in the obscuration properties across the mass range. (ProQuest: ... denotes formulae/symbols omitted.)
Multiple trace-gas instruments were deployed during the fourth Fire Lab at Missoula Experiment (FLAME-4), including the first application of proton-transfer-reaction time-of-flight mass spectrometry ...(PTR-TOFMS) and comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC-TOFMS) for laboratory biomass burning (BB) measurements. Open-path Fourier transform infrared spectroscopy (OP-FTIR) was also deployed, as well as whole-air sampling (WAS) with one-dimensional gas chromatography–mass spectrometry (GC-MS) analysis. This combination of instruments provided an unprecedented level of detection and chemical speciation. The chemical composition and emission factors (EFs) determined by these four analytical techniques were compared for four representative fuels. The results demonstrate that the instruments are highly complementary, with each covering some unique and important ranges of compositional space, thus demonstrating the need for multi-instrument approaches to adequately characterize BB smoke emissions. Emission factors for overlapping compounds generally compared within experimental uncertainty, despite some outliers, including monoterpenes. Data from all measurements were synthesized into a single EF database that includes over 500 non-methane organic gases (NMOGs) to provide a comprehensive picture of speciated, gaseous BB emissions. The identified compounds were assessed as a function of volatility; 6–11 % of the total NMOG EF was associated with intermediate-volatility organic compounds (IVOCs). These atmospherically relevant compounds historically have been unresolved in BB smoke measurements and thus are largely missing from emission inventories. Additionally, the identified compounds were screened for published secondary organic aerosol (SOA) yields. Of the total reactive carbon (defined as EF scaled by the OH rate constant and carbon number of each compound) in the BB emissions, 55–77 % was associated with compounds for which SOA yields are unknown or understudied. The best candidates for future smog chamber experiments were identified based on the relative abundance and ubiquity of the understudied compounds, and they included furfural, 2-methyl furan, 2-furan methanol, and 1,3-cyclopentadiene. Laboratory study of these compounds will facilitate future modeling efforts.
We use the United Kingdom Infrared Telescope Deep Sky Survey (UKIDSS) Ultra Deep Survey (UDS), the deepest degree-scale near-infrared survey to date, to investigate the clustering of star-forming and ...passive galaxies to z ∼ 3.5. Our new measurements include the first determination of the clustering for passive galaxies at z > 2, which we achieve using a cross-correlation technique. We find that passive galaxies are the most strongly clustered, typically hosted by massive dark matter haloes with M
halo > 5 × 1012 M irrespective of redshift or stellar mass. Our findings are consistent with models in which a critical halo mass determines the transition from star-forming to passive galaxies. Star-forming galaxies show no strong correlation between stellar mass and halo mass, but passive galaxies show evidence for an anticorrelation; low-mass passive galaxies appear, on average, to be located in the most massive haloes. These results can be understood if the termination of star formation is most efficient for galaxies of low stellar mass in very dense environments.
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