Layered aluminosilicates play a dominant role in the mechanical and gas storage properties of the subsurface, are used in diverse industrial applications, and serve as model materials for ...understanding solvent–ion-support systems. Although expansion in the presence of H2O is well-known to be systematically correlated with the hydration free energy of the interlayer cation, particularly in environments dominated by nonpolar solvents (i.e., CO2), uptake into the interlayer is not well-understood. Using novel high-pressure capabilities, we investigated the interaction of dry supercritical CO2 with Na-, NH4-, and Cs-saturated montmorillonite, comparing results with predictions from molecular dynamics simulations. Despite the known trend in H2O and that cation solvation energies in CO2 suggest a stronger interaction with Na, both the NH4- and Cs-clays readily absorbed CO2 and expanded, while the Na-clay did not. The apparent inertness of the Na-clay was not due to kinetics, as experiments seeking a stable expanded state showed that none exists. Molecular dynamics simulations revealed a large endothermicity to CO2 intercalation in the Na-clay but little or no energy barrier for the NH4- and Cs-clays. Indeed, the combination of experiment and theory clearly demonstrate that CO2 intercalation of Na-montmorillonite clays is prohibited in the absence of H2O. Consequently, we have shown for the first time that in the presence of a low dielectric constant, gas swelling depends more on the strength of the interaction between the interlayer cation and aluminosilicate sheets and less on that with solvent. The finding suggests a distinct regime in layered aluminosilicate swelling behavior triggered by low solvent polarizability, with important implications in geomechanics, storage, and retention of volatile gases, and across industrial uses in gelling, decoloring, heterogeneous catalysis, and semipermeable reactive barriers.
We present the measurement of the two-point cross-correlation function (CCF) of 8198 Sloan Digital Sky Survey Data Release 7 quasars and 349,608 Data Release 10 CMASS galaxies from the Baryonic ...Oscillation Spectroscopic Survey at 0.3 < z < 0.9. Based on the clustering measurements, most quasars at z ~ 0.5 are not the descendants of their higher luminosity counterparts at higher redshift, which would have evolved into more massive and more biased systems at low redshift. The host halo mass distributions significantly overlap with each other for quasars at different luminosities, implying a poor correlation between halo mass and instantaneous quasar luminosity. We also find that the quasar HOD parameterization is largely degenerate such that different HODs can reproduce the CCF equally well, but with different satellite fractions and host halo mass distributions. These results highlight the limitations and ambiguities in modeling the distribution of quasars with the standard HOD approach.
This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the ...Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17).
We present paper six of the NIRSPEC Brown Dwarf Spectroscopic Survey, an analysis of multi-epoch, high-resolution (R~20,000) spectra of 25 field dwarf systems (3 late-type M dwarfs, 16 L dwarfs, and ...6 T dwarfs) taken with the NIRSPEC infrared spectrograph at the W. M. Keck Observatory. With a radial velocity precision of ~2 km/s, we are sensitive to brown dwarf companions in orbits with periods of a few years or less given a mass ratio of 0.5 or greater. We do not detect any spectroscopic binary brown dwarfs in the sample. Given our target properties, and the frequency and cadence of observations, we use a Monte Carlo simulation to determine the detection probability of our sample. Even with a null detection result, our 1 sigma upper limit for very low mass binary frequency is 18%. Our targets included 7 known, wide brown dwarf binary systems. No significant radial velocity variability was measured in our multi-epoch observations of these systems, even for those pairs for which our data spanned a significant fraction of the orbital period. Specialized techniques are required to reach the high precisions sensitive to motion in orbits of very low-mass systems. For eight objects, including six T dwarfs, we present the first published high-resolution spectra, many with high signal to noise, that will provide valuable comparison data for models of brown dwarf atmospheres.
During the first 5 years of life, children are especially vulnerable to infection-related morbidity and mortality. Conversely, the Hygiene Hypothesis suggests that a lack of exposure to infectious ...agents early in life could explain the increasing incidence of allergies and autoimmunity in high-income countries. Understanding these phenomena, however, is hampered by a lack of comprehensive, direct immune monitoring in children with differing degrees of microbial exposure. Using mass cytometry, we provide an in-depth profile of the peripheral blood mononuclear cells (PBMCs) of children in regions at the extremes of exposure: the San Francisco Bay Area, USA and an economically poor district of Dhaka, Bangladesh. Despite variability in clinical health, functional characteristics of PBMCs were similar in Bangladeshi and American children at 1 year of age. However, by 2-3 years of age, Bangladeshi children's immune cells often demonstrated altered activation and cytokine production profiles upon stimulation with PMA-ionomycin, with an overall immune trajectory more in line with American adults. Conversely, immune responses in children from the US remained steady. Using principal component analysis, donor location, ethnic background, and cytomegalovirus infection status were found to account for some of the variation identified among samples. Within Bangladeshi 1-year-olds, stunting (as measured by height-for-age z-scores) was found to be associated with IL-8 and TGFβ expression in PMA-ionomycin stimulated samples. Combined, these findings provide important insights into the immune systems of children in high vs. low microbial exposure environments and suggest an important role for IL-8 and TGFβ in mitigating the microbial challenges faced by the Bangladeshi children.
In Australia, suburban front gardens have been said to be for show, while back gardens have been thought to be used more productively. This pattern may have changed as a result of a change in the ...ways that western suburbanites use and value their gardens. In 107 gardens in 10 suburbs of Hobart, Tasmania, Australia, data on the floristic composition, structural characteristics and some use attributes were collected from front and back yards. The floristic data were used to classify the yards into types, many of which preferentially occurred in either front or back. Back yards preferentially containing food plant taxa, and had a larger proportion of lawn, dogs and chicken coops, while front yards preferentially contained showy and screening plant taxa, and had relatively high small shrub cover. However, in a large proportion of properties, the garden type in the front yard was the same as the type in the back yard. In another large proportion of properties the front yard was gardened more intensively than the back, indicating a desire to impress, but the back yard was not used for productive purposes. These gardens preferentially occurred in the older suburbs, while gardens that were showier in the back than the front were negatively correlated with the unemployment rate. In a relatively small proportion of properties showy gardens were located in the front yard, while productive gardens were located in the back yard. The prevalence of these gardens had no relationships with suburb characteristics. The wide variety of garden types, and of their combinations in back and front yards, both within and between suburbs, indicate a complexity not reducible to simple aphorisms.
Abstract
We present rest-frame optical emission-line flux ratio measurements for five
z
> 5 galaxies observed by the James Webb Space Telescope Near-Infared Spectrograph (NIRSpec) in the SMACS 0723 ...Early Release Observations. We add several quality-control and post-processing steps to the NIRSpec pipeline reduction products in order to ensure reliable
relative
flux calibration of emission lines that are closely separated in wavelength, despite the uncertain
absolute
spectrophotometry of the current version of the reductions. Compared to
z
∼ 3 galaxies in the literature, the
z
> 5 galaxies have similar O
iii
λ
5008/H
β
ratios, similar O
iii
λ
4364/H
γ
ratios, and higher (∼0.5 dex) Ne
III
λ
3870/O
II
λ
3728 ratios. We compare the observations to MAPPINGS V photoionization models and find that the measured Ne
III
λ
3870/O
II
λ
3728, O
iii
λ
4364/H
γ
, and O
iii
λ
5008/H
β
emission-line ratios are consistent with an interstellar medium (ISM) that has very high ionization (
log
(
Q
)
≃
8
−
9
, units of cm s
−1
), low metallicity (
Z
/
Z
⊙
≲ 0.2), and very high pressure (
log
(
P
/
k
)
≃
8
−
9
, units of cm
−3
). The combination of O
iii
λ
4364/H
γ
and O
iii
λ
(4960 + 5008)/H
β
line ratios indicate very high electron temperatures of
4.1
<
log
(
T
e
/
K
)
<
4.4
, further implying metallicities of
Z
/
Z
⊙
≲ 0.2 with the application of low-redshift calibrations for “
T
e
-based” metallicities. These observations represent a tantalizing new view of the physical conditions of the ISM in galaxies at cosmic dawn.
An abstract of a study by Timofeev et al evaluating the association between cerebral chemistry and outcome after traumatic brain injury (TBI) in a large cohort of patients is presented. The results ...of this study suggest that extracellular metabolic markers are independently associated with outcome following TBI, with L/P ratio being the most consistent predictor. Whether treatment related improvement in biochemistry translates into better clinical outcome remains to be established.
During severe influenza A virus (IAV) infections, a large amount of damage to the pulmonary epithelium is the result of the antiviral immune response. Specifically, whilst CD8
T cells are important ...for killing IAV-infected cells, during a severe IAV infection, they can damage uninfected epithelial cells. At present, the mechanisms by which this occurs are unclear. Here, we used a novel in vitro coculture model of human NCl-H441 cells and CD8
T cells to provide a new insight into how CD8
T cells may affect uninfected epithelial cells during severe IAV infections. Using this model, we show that human IAV-specific CD8
T cells produce soluble factors that reduce the barrier integrity of noninfected epithelial cells (referred to as "bystander damage"). We show that this bystander damage is the result of a combination of TNF-α and IFN-γ. This bystander damage occurred in the absence of widespread epithelial cell death and was instead associated with decreased expression of epithelial cell ion channels and pumps. Together, these data suggest that ameliorating the function of epithelial cell ion channels and pumps may help reduce immunopathology during severe IAV infections.
•Ratings of trust in ADAS technologies increased with length of ownership.•Just under half of participants reported experiencing unexpected ADAS behavior.•Unexpected system behavior decreased ...participant ratings of trust over time.•Most participants reported receiving an informal overview of the ADAS technologies.•Training efficacy was rated higher by those who received formal training.
Two-hundred and twenty-three participants completed an online survey regarding their experiences with advanced driver assistance systems (ADAS) on their personal vehicles, with focus on 1) drivers’ trust in 13 ADAS technologies, and 2) perceived effectiveness of currently used methods of training. Eighteen drivers participated in focus groups designed to probe more deeply into survey responses. Results of the survey showed that participant ratings of trust increased significantly with longer vehicle ownership, but participants who experienced unexpected ADAS technology behavior rated their trust over time significantly lower on ADAS technologies with the exception of rear collision avoidance. The majority (75.8%) of participants reported receiving some ADAS instruction at their vehicle dealership, but only 16.6% indicated it was formal. Participants who received formalized training reported it to be significantly more effective than those who received informal overviews of their systems. Use of trial and error and the owner’s manual were the most frequently reported methods of learning outside of dealership training. Responses indicated that the lack of content tailored to trim-specific vehicle features in owner’s manuals was a barrier to effective use.
PDF
