2,857 research outputs found
The Atlantic Water boundary current in the Chukchi Borderland and Southern Canada Basin
Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 125(8), (2020): e2020JC016197, doi:10.1029/2020JC016197.Synoptic shipboard measurements, together with historical hydrographic data and satellite data, are used to elucidate the detailed structure of the Atlantic Water (AW) boundary current system in the southern Canada Basin and its connection to the upstream source of AW in the Chukchi Borderland. Nine highâresolution occupations of a transect extending from the Beaufort shelf to the deep basin near 152°W, taken between 2003 and 2018, reveal that there are two branches of the AW boundary current that flow beneath and counter to the Beaufort Gyre. Each branch corresponds to a warm temperature core and transports comparable amounts of Fram Strait Branch Water between roughly 200â700 m depth, although they are characterized by a different temperature/salinity (T/S) structure. The mean volume flux of the combined branches is 0.87 ± 0.13 Sv. Using the historical hydrographic data, the two branches are tracked upstream by their temperature cores and T/S signatures. This sheds new light on how the AW negotiates the Chukchi Borderland and why two branches emerge from this region. Lastly, the propagation of warm temperature anomalies through the region is quantified and shown to be consistent with the deduced circulation scheme.This work was funded by the following sources: National Science Foundation Grants PLRâ1504333, OPPâ1733564, and OPPâ1504394; National Oceanic and Atmospheric Administration Grant NA14OAR4320158; and National Aeronautics and Space Administration Grant NNX10AF42G.2021-01-2
Demography of SDSS early-type galaxies from the perspective of radial color gradients
We have investigated the radial g-r color gradients of early-type galaxies in
the Sloan Digital Sky Survey (SDSS) DR6 in the redshift range 0.00<z<0.06. The
majority of massive early-type galaxies show a negative color gradient
(red-cored) as generally expected for early-type galaxies. On the other hand,
roughly 30 per cent of the galaxies in this sample show a positive color
gradient (blue-cored). These "blue-cored" galaxies often show strong H beta
absorption line strengths and/or emission line ratios that are indicative of
the presence of young stellar populations. Combining the optical data with
Galaxy Evolution Explorer (GALEX) UV photometry, we find that all blue-cored
galaxies show UV-optical colors that can only be explained by young stellar
populations. This implies that most of the residual star formation in
early-type galaxies is centrally concentrated. Blue-cored galaxies are
predominantly low velocity dispersion systems. A simple model shows that the
observed positive color gradients (blue-cored) are visible only for a billion
years after a star formation episode for the typical strength of recent star
formation. The observed effective radius decreases and the mean surface
brightness increases due to this centrally-concentrated star formation episode.
As a result, the majority of blue-cored galaxies may lie on different regions
in the Fundamental Plane from red-cored ellipticals. However, the position of
the blue-cored galaxies on the Fundamental Plane cannot be solely attributed to
recent star formation but require substantially lower velocity dispersion. We
conclude that a low-level of residual star formation persists at the centers of
most of low-mass early-type galaxies, whereas massive ones are mostly quiescent
systems with metallicity-driven red cores.Comment: 15 pages, 19 figures, accepted for publication in ApJ
The shadow knows: using shadows to investigate the structure of the pretransitional disk of HD 100453
We present GPI polarized intensity imagery of HD 100453 in Y-, J-, and K1
bands which reveals an inner gap ( au), an outer disk ( au) with
two prominent spiral arms, and two azimuthally-localized dark features also
present in SPHERE total intensity images (Wagner 2015). SED fitting further
suggests the radial gap extends to au. The narrow, wedge-like shape of the
dark features appears similar to predictions of shadows cast by a inner disk
which is misaligned with respect to the outer disk. Using the Monte Carlo
radiative transfer code HOCHUNCK3D (Whitney 2013), we construct a model of the
disk which allows us to determine its physical properties in more detail. From
the angular separation of the features we measure the difference in inclination
between the disks 45, and their major axes, PA = 140 east
of north for the outer disk and 100for the inner disk. We find an
outer disk inclination of from face-on in broad agreement
with the Wagner 2015 measurement of 34. SPHERE data in J- and H-bands
indicate a reddish disk which points to HD 100453 evolving into a young debris
disk
Deterministic Magnetization Switching Using Lateral SpinâOrbit Torque
Current-induced magnetization switching by spin-orbit torque (SOT) holds
considerable promise for next generation ultralow-power memory and logic
applications. In most cases, generation of spin-orbit torques has relied on an
external injection of out-of-plane spin currents into the magnetic layer, while
an external magnetic field along the electric current direction is generally
required for realizing deterministic switching by SOT. Here, we report
deterministic current-induced SOT full magnetization switching by lateral
spin-orbit torque in zero external magnetic field. The Pt/Co/Pt magnetic
structure was locally annealed by a laser track along the in-plane current
direction, resulting in a lateral Pt gradient within the ferromagnetic layer,
as confirmed by microstructure and chemical composition analysis. In zero
magnetic field, the direction of the deterministic current-induced
magnetization switching depends on the location of the laser track, but shows
no dependence on the net polarization of external out-of-plane spin currents.
From the behavior under external magnetic fields, we identify two independent
mechanisms giving rise to SOT, i.e. the lateral Pt-Co asymmetry as well as
out-of-plane injected spin currents, where the polarization and the magnitude
of the SOT in the former case depends on the relative location and the laser
power of the annealing track. Our results demonstrate an efficient field-free
deterministic full magnetization switching scheme, without requiring
out-of-plane spin current injection or complex external stack structures.Comment: 39 Pages, 9 Figure
Towards ASR Robust Spoken Language Understanding Through In-Context Learning With Word Confusion Networks
In the realm of spoken language understanding (SLU), numerous natural
language understanding (NLU) methodologies have been adapted by supplying large
language models (LLMs) with transcribed speech instead of conventional written
text. In real-world scenarios, prior to input into an LLM, an automated speech
recognition (ASR) system generates an output transcript hypothesis, where
inherent errors can degrade subsequent SLU tasks. Here we introduce a method
that utilizes the ASR system's lattice output instead of relying solely on the
top hypothesis, aiming to encapsulate speech ambiguities and enhance SLU
outcomes. Our in-context learning experiments, covering spoken question
answering and intent classification, underline the LLM's resilience to noisy
speech transcripts with the help of word confusion networks from lattices,
bridging the SLU performance gap between using the top ASR hypothesis and an
oracle upper bound. Additionally, we delve into the LLM's robustness to varying
ASR performance conditions and scrutinize the aspects of in-context learning
which prove the most influential.Comment: Accepted to ICASSP 202
Association of early childhood constipation with the risk of autism spectrum disorder in Taiwan: Real-world evidence from a nationwide population-based cohort study
BackgroundAutism spectrum disorder (ASD) is a neurodevelopmental problem that presents with limited interests, repetitive behaviors, and deficits in reciprocal communication and social interactions. Mounting evidence indicates that an imbalanced gut microbiota contributes to autism via the gut-brain axis. Constipation may result in alteration of the gut microbiota. The clinical influence of constipation on ASD has not been fully researched. Thus, in this study we aimed to evaluate whether early childhood constipation influenced the risk of developing ASD using a nationwide population-based cohort study.MethodsWe identified 12,935 constipated children aged 3âyears or younger from the National Health Insurance Research Database (NHIRD) in Taiwan from 1997 to 2013. Non-constipated children were also selected from the database and propensity score matching of age, gender, and underlying comorbidities was conducted with a ratio of 1:1. KaplanâMeier analysis was applied to determine different levels of constipation severity and cumulative incidence of autism. Subgroup analysis was also applied in this study.ResultsThe incidence rate of ASD was 12.36 per 100,000 person-months in the constipation group, which was higher than the rate of 7.84 per 100,000 person-months noted in the non-constipation controls. Constipated children had a significantly higher risk of autism when compared to the non-constipation group (crude relative riskâ=â1.458, 95% CIâ=â1.116â1.904; adjusted hazard ratioâ=â1.445, 95% CIâ=â1.095â1.907).Moreover, among constipated children, a higher number of laxative prescriptions, male gender, constipation during infancy, and atopic dermatitis were significantly associated with higher risks of ASD when compared to the non-constipation group.ConclusionConstipation in early childhood was correlated with a significantly increased risk of ASD. Clinicians should pay attention to the possibility of ASD in constipated children. Further research is necessary to study the possible pathophysiological mechanisms of this association
Murine factor H co-produced in yeast with protein disulfide isomerase ameliorated C3 dysregulation in factor H-Deficient mice
Recombinant human factor H (hFH) has potential for treating diseases linked to aberrant complement regulation including C3 glomerulopathy (C3G) and dry age-related macular degeneration. Murine FH (mFH), produced in the same host, is useful for pre-clinical investigations in mouse models of disease. An abundance of FH in plasma suggests high doses, and hence microbial production, will be needed. Previously, Pichia pastoris produced useful but modest quantities of hFH. Herein, a similar strategy yielded miniscule quantities of mFH. Since FH has 40 disulfide bonds, we created a P. pastoris strain containing a methanol-inducible codon-modified gene for protein-disulfide isomerase (PDI) and transformed this with codon-modified DNA encoding mFH under the same promoter. What had been barely detectable yields of mFH became multiple 10s of mg/L. Our PDI-overexpressing strain also boosted hFH overproduction, by about tenfold. These enhancements exceeded PDI-related production gains reported for other proteins, all of which contain fewer disulfide-stabilized domains. We optimized fermentation conditions, purified recombinant mFH, enzymatically trimmed down its (non-human) N-glycans, characterised its functions in vitro and administered it to mice. In FH-knockout mice, our de-glycosylated recombinant mFH had a shorter half-life and induced more anti-mFH antibodies than mouse serum-derived, natively glycosylated, mFH. Even sequential daily injections of recombinant mFH failed to restore wild-type levels of FH and C3 in mouse plasma beyond 24 hours after the first injection. Nevertheless, mFH functionality appeared to persist in the glomerular basement membrane because C3-fragment deposition here, a hallmark of C3G, remained significantly reduced throughout and beyond the ten-day dosing regimen
Application of targeted molecular and material property optimization to bacterial attachment-resistant (meth)acrylate polymers
Developing medical devices that resist bacterial attachment and subsequent biofilm formation is highly desirable. In this paper, we report the optimization of the molecular structure and thus material properties of a range of (meth)acrylate copolymers which contain monomers reported to deliver bacterial resistance to surfaces. This optimization allows such monomers to be employed within novel coatings to reduce bacterial attachment to silicone urinary catheters. We show that the flexibility of copolymers can be tuned to match that of the silicone catheter substrate, by copolymerizing these polymers with a lower Tg monomer such that it passes the flexing fatigue tests as coatings upon catheters, that the homopolymers failed. Furthermore, the Tg values of the copolymers are shown to be readily estimated by the Fox equation. The bacterial resistance performance of these copolymers were typically found to be better than the neat silicone or a commercial silver containing hydrogel surface, when the monomer feed contained only 25 v% of the âhitâ monomer. The method of initiation (either photo or thermal) was shown not to affect the bacterial resistance of the copolymers. Optimized synthesis conditions to ensure that the correct copolymer composition and to prevent the onset of gelation are detailed
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