3,436 research outputs found
Resolved Depletion Zones and Spatial Differentiation of N2H+ and N2D+
We present a study on the spatial distribution of N2D+ and N2H+ in thirteen
protostellar systems. Eight of thirteen objects observed with the IRAM 30m
telescope show relative offsets between the peak N2D+ (J=2-1) and N2H+ (J=1-0)
emission. We highlight the case of L1157 using interferometric observations
from the Submillimeter Array and Plateau de Bure Interferometer of the N2D+
(J=3-2) and N2H+ (J=1-0) transitions respectively. Depletion of N2D+ in L1157
is clearly observed inside a radius of ~2000 AU (7") and the N2H+ emission is
resolved into two peaks at radii of ~1000 AU (3.5"), inside the depletion
region of N2D+. Chemical models predict a depletion zone in N2H+ and N2D+ due
to destruction of H2D+ at T ~ 20 K and the evaporation of CO off dust grains at
the same temperature. However, the abundance offsets of 1000 AU between the two
species are not reproduced by chemical models, including a model that follows
the infall of the protostellar envelope. The average abundance ratios of N2D+
to N2H+ have been shown to decrease as protostars evolve by Emprechtinger et
al., but this is the first time depletion zones of N2D+ have been spatially
resolved. We suggest that the difference in depletion zone radii for N2H+ and
N2D+ is caused by either the CO evaporation temperature being above 20 K or an
H2 ortho-to-para ratio gradient in the inner envelope.Comment: Accepted to ApJ. 44 pages 13 Figure
Factors That Promote Perceived Usefulness of and Clinical Outcomes From Sign-Outs at the National University Hospital
IMPORTANCE OF THE STUDY. Currently, there is a paucity of evidence in the literature to show that handoff strategies improve the quality of handoff outcomes. Studies that show the usefulness and outcomes obtained from sign-outs may motivate junior clinicians, who have limited time to perform their clinical responsibilities, to support sign-out improvement efforts.
OBJECTIVE. To test a research model that embeds the Technology Acceptance Model and the Theory of Planned Behavior to explore factors that enhance the perceived (a) usefulness of and (b) clinical outcomes from sign-outs among junior medical officers.
DESIGN, SETTING, AND PARTICIPANTS.
A retrospective study was conducted in the Division of General Medicine in November 2012. 17 residents volunteered to participate in a theoretically validated survey.
MEASURES AND ANALYSES. The predictor variables were Perceived Ease of Sign-outs, Perceived Benefits from Sign-outs, Attitudes towards Sign-outs, Social Norms to Sign-out, and Perceived Behavior Control over Sign-outs. Partial Least Squares with bootstrapping to 1000 cases was utilized to analyze the data from a small sample.
RESULTS.
The results showed that perceived benefits from sign-outs enhanced the perceived usefulness of sign-outs. Perceived ease of sign-outs enhanced attitudes towards sign-outs, which was significantly related to perceptions of positive clinical outcomes from sign-outs. Neither the social pressure to sign-out nor the provision of conditions to facilitate sign-outs had any significant relationships to perceived usefulness of or clinical outcomes derived from sign-outs.
CONCLUSION AND RELEVANCE. A two-prong approach involving minimal effort and hard evidence from clinical outcomes may be required to motivate adoption of sign-outs by busy residents
Estimating the microbiological risks associated with inland flood events:bridging theory and models of pathogen transport
Flooding is known to facilitate infectious disease transmission, yet quantitative research on microbiological risks associated with floods has been limited. Pathogen fate and transport models provide a framework to examine interactions between landscape characteristics, hydrology, and waterborne disease risks, but have not been widely developed for flood conditions. We critically examine capabilities of current hydrological models to represent unusual flow paths, non-uniform flow depths, and unsteady flow velocities that accompany flooding. We investigate the theoretical linkages between hydrodynamic processes and spatio-temporally variable suspension and deposition of pathogens from soils and sediments; pathogen dispersion in flow; and concentrations of constituents influencing pathogen transport and persistence. Identifying gaps in knowledge and modeling practice, we propose a research agenda to strengthen microbial fate and transport modeling applied to inland floods: 1) development of models incorporating pathogen discharges from flooded sources (e.g., latrines), effects of transported constituents on pathogen persistence, and supply-limited pathogen transport; 2) studies assessing parameter identifiability and comparing model performance under varying degrees of process representation, in a range of settings; 3) development of remotely sensed datasets to support modeling of vulnerable, data-poor regions; and 4) collaboration between modelers and field-based researchers to expand the collection of useful data in situ
Gaia-DR2 confirms VLBA parallaxes in Ophiuchus, Serpens and Aquila
We present Gaia-DR2 astrometry of a sample of YSO candidates in Ophiuchus,
Serpens Main and Serpens South/W40 in the Aquila Rift, which had been mainly
identified by their infrared excess with Spitzer. We compare the Gaia-DR2
parallaxes against published and new parallaxes obtained from our Very Long
Baseline Array (VLBA) program GOBELINS. We obtain consistent results between
Gaia and the VLBA for the mean parallaxes in each of the regions analyzed here.
We see small offsets, when comparing mean values, of a few tens of
micro-arcseconds in the parallaxes, which are either introduced by the Gaia
zero-point error or due to a selection effect by Gaia toward the brightest,
less obscured stars. Gaia-DR2 data alone conclusively places Serpens Main and
Serpens South at the same distance, as we first inferred from VLBA data alone
in a previous publication. Thus, Serpens Main, Serpens South and W40 are all
part of the same complex of molecular clouds, located at a mean distance of
436+/-9 pc. In Ophiuchus, both Gaia and VLBA suggest a small parallax gradient
across the cloud, and the distance changes from 144.2+/-1.3 pc to 138.4+/-2.6
pc when going from L1689 to L1688.Comment: Accepted for publication in ApJ
Promoting Community Engagement: A Campus-Wide Approach to Applied Learning
Applied learning pedagogy has gained momentum in recent decades. Simultaneously, a call for universities to respond to the needs of local and global communities has prompted a focus on community engagement in higher education. The purpose of this paper is to describe the development of the Applied Learning and Teaching Community (ALTC), an initiative designed to further integrate applied learning—including community engagement— into the identity, practice, and teaching ethos of the university. With a focus on sustainability, the ALTC has evolved into an expansive model that involves faculty, staff, students, and other supporters across campus. A discussion of the ALTC’s relevance in the context of current trends in higher education is included
The Gould's Belt Distances Survey (GOBELINS). V. Distances and Kinematics of the Perseus molecular cloud
We derive the distance and structure of the Perseus molecular cloud by
combining trigonometric parallaxes from Very Long Baseline Array (VLBA)
observations, taken as part of the GOBELINS survey, and Gaia Data Release 2.
Based on our VLBA astrometry, we obtain a distance of 321+/-10 pc for IC 348.
This is fully consistent with the mean distance of 320+/-26 measured by Gaia.
The VLBA observations toward NGC 1333 are insufficient to claim a successful
distance measurement to this cluster. Gaia parallaxes, on the other hand, yield
a mean distance of 293+/-22 pc. Hence, the distance along the line of sight
between the eastern and western edges of the cloud is ~30 pc, which is
significantly smaller than previously inferred. We use Gaia proper motions and
published radial velocities to derive the spatial velocities of a selected
sample of stars. The average velocity vectors with respect to the LSR are
(u,v,w) = (-6.1+/-1.6, 6.8+/-1.1, -0.9+/-1.2) and (-6.4+/-1.0, 2.1+/-1.4,
-2.4+/-1.0) km/s for IC 348 and NGC 1333, respectively. Finally, our analysis
of the kinematics of the stars has shown that there is no clear evidence of
expansion, contraction, or rotational motions within the clusters.Comment: Accepted for publication in Ap
Cooperative Carbon Dioxide Adsorption in Alcoholamine- and Alkoxyalkylamine-Functionalized Metal-Organic Frameworks.
A series of structurally diverse alcoholamine- and alkoxyalkylamine-functionalized variants of the metal-organic framework Mg2 (dobpdc) are shown to adsorb CO2 selectively via cooperative chain-forming mechanisms. Solid-state NMR spectra and optimized structures obtained from van der Waals-corrected density functional theory calculations indicate that the adsorption profiles can be attributed to the formation of carbamic acid or ammonium carbamate chains that are stabilized by hydrogen bonding interactions within the framework pores. These findings significantly expand the scope of chemical functionalities that can be utilized to design cooperative CO2 adsorbents, providing further means of optimizing these powerful materials for energy-efficient CO2 separations
A Pilot Study on Nurse-Led Rounds: Preliminary Data on Patient Contact Time
IMPORTANCE OF THE STUDY. Ward rounding has been a historical clinical method of inter-professional collaboration to support inpatient care through the sharing of mental models by exchanging information and discussing plans of care, treatment goals, and discharge plans for the patient. The extant literature reports that rounds are frequently led by doctors with infrequent nurse-physician collaboration and patients’ interactions with doctors during ward rounds tend to be brief.
OBJECTIVE. To explore the effects of nurse-led morning ward rounds on patient contact time.
DESIGN. An ethnographic prospective observational study comparing nurse-led and physician-led rounds. SETTING. A General Medicine ward at the National University Hospital in Singapore.
INTERVENTION. A pilot intervention of nurse-led ward rounds for one week in June 2014. In the pilot intervention, nurses used the SPICES mnemonic to present their patients’ conditions to the clinical teams during morning rounds.
MEASURES AND ANALYSES. Two observers shadowed the clinical teams for 57 patients. The amount of time that the clinical teams spent at the bedside of each patient was recorded.
RESULTS. The results showed that the average time spent with patients at the bedside was significantly longer for nurse-led rounds compared to physician-led rounds. Also, the average time spent with patients at the bedside trended down toward the end of the 2-hour morning round time for resident-led ward rounds but it remained relatively consistent with an upward trend near the end of the 2-hour morning round for nurse-led rounds.
CONCLUSION. The preliminary data suggests that quality time spent with patients at the bedside during morning rounds may be improved by nurse-led rounds
Specific inhibition of c-Jun N-terminal kinase delays preterm labour and reduces mortality
Preterm labour (PTL) is commonly associated with infection and/or inflammation. Lipopolysaccharide (LPS) from different bacteria can be used to independently or mutually activate Jun N-terminal kinase (JNK)/AP1- or NF-kB-driven inflammatory pathways that lead to PTL. Previous studies using Salmonella abortus LPS, which activates both JNK/AP-1 and NF-kB, showed that selective inhibition of NF-kB delays labour and improves pup outcome. Where labour is induced using Escherichia coli LPS (O111), which upregulates JNK/AP-1 but not NF-kB, inhibition of JNK/AP-1 activation also delays labour. In this study, to determine the potential role of JNK as a therapeutic target in PTL, we investigated the specific contribution of JNK signalling to S. Abortus LPS-induced PTL in mice. Intrauterine administration of S. Abortus LPS to pregnant mice resulted in the activation of JNK in the maternal uterus and fetal brain, upregulation of pro-inflammatory proteins COX-2, CXCL1, and CCL2, phosphorylation of cPLA2 in myometrium, and induction of PTL. Specific inhibition of JNK by co-administration of specific D-JNK inhibitory peptide (D-JNKI) delayed LPS-induced preterm delivery and reduced fetal mortality. This is associated with inhibition of myometrial cPLA2 phosphorylation and proinflammatory proteins synthesis. In addition, we report that D-JNKI inhibits the activation of JNK/JNK3 and caspase-3, which are important mediators of neural cell death in the neonatal brain. Our data demonstrate that specific inhibition of TLR4-activated JNK signalling pathways has potential as a therapeutic approach in the management of infection/inflammation-associated PTL and prevention of the associated detrimental effects to the neonatal brain
Nanoparticle Encapsidation of Flock House Virus by Auto Assembly of Tobacco Mosaic Virus Coat Protein
Tobacco Mosaic virus (TMV) coat protein is well known for its ability to self-assemble into supramolecular nanoparticles, either as protein discs or as rods originating from the ~300 bp genomic RNA origin-of-assembly (OA). We have utilized TMV self-assembly characteristics to create a novel Flock House virus (FHV) RNA nanoparticle. FHV encodes a viral polymerase supporting autonomous replication of the FHV genome, which makes it an attractive candidate for viral transgene expression studies and targeted RNA delivery into host cells. However, FHV viral genome size is strictly limited by native FHV capsid. To determine if this packaging restriction could be eliminated, FHV was adapted to express enhanced green fluorescent protein (GFP), to allow for monitoring of functional FHV RNA activity. Then TMV OA was introduced in six 3\u27 insertion sites, with only site one supporting functional FHV GFP expression. To create nanoparticles, FHV GFP-OA modified genomic RNA was mixed in vitro with TMV coat protein and monitored for encapsidation by agarose electrophoresis and electron microscopy. The production of TMV-like rod shaped nanoparticles indicated that modified FHV RNA can be encapsidated by purified TMV coat protein by self-assembly. This is the first demonstration of replication-independent packaging of the FHV genome by protein self-assembly
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