1,947 research outputs found
VLT observations of the asymmetric Etched Hourglass Nebula, MyCn 18
Context. The mechanisms that form extreme bipolar planetary nebulae remain
unclear. Aims. The physical properties, structure, and dynamics of the bipolar
planetary nebula, MyCn 18, are investigated in detail with the aim of
understanding the shaping mechanism and evolutionary history of this object.
Methods. VLT infrared images, VLT ISAAC infrared spectra, and long-slit optical
Echelle spectra are used to investigate MyCn 18. Morpho-kinematic modelling was
used to firmly constrain the structure and kinematics of the source. A
timescale analysis was used to determine the kinematical age of the nebula and
its main components. Results. A spectroscopic study of MyCn 18's central and
offset region reveals the detailed make-up of its nebular composition.
Molecular hydrogen, atomic helium, and Bracket gamma emission are detected from
the central regions of MyCn 18. ISAAC spectra from a slit position along the
narrow waist of the nebula demonstrate that the ionised gas resides closer to
the centre of the nebula than the molecular emission. A kinematical age of the
nebula and its components were obtained by the P-V arrays and timescale
analysis. Conclusions. The structure and kinematics of MyCn 18 are better
understood using an interactive 3-D modelling tool called shape. A dimensional
and timescale analysis of MyCn 18's major components provides a possible
mechanism for the nebula's asymmetry. The putative central star is somewhat
offset from the geometric centre of the nebula, which is thought to be the
result of a binary system. We speculate that the engulfing and destruction of
an exoplanet during the AGB phase may have been a key event in shaping MyCn 18
and generating of its hypersonic knotty outflow.Comment: 15 pages, 3 tables, 13 figures. Accepted for publication by A&
Manufacturing with the Sun
Concentrated solar radiation is now a viable alternative source for many advanced manufacturing processes. Researchers at the National Renewable Energy Laboratory (NREL) have demonstrated the feasibility of processes such as solar induced surface transformation of materials (SISTM), solar based manufacturing, and solar pumped lasers. Researchers are also using sunlight to decontaminate water and soils polluted with organic compounds; these techniques could provide manufacturers with innovative alternatives to traditional methods of waste management. The solar technology that is now being integrated into today's manufacturing processes offer greater potential for tomorrow, especially as applied to the radiation abundant environment available in space and on the lunar surface
Exposure of Bifidobacterium longum subsp. infantis to Milk Oligosaccharides Increases Adhesion to Epithelial Cells and Induces a Substantial Transcriptional Response
Devon Kavanaugh is in receipt of a Teagasc Walsh Fellowship. The authors would also like to acknowledge the support of Science Foundation Ireland under Grant No. 08/SRC/B1393 and the Alimentary Glycoscience Research Cluster (AGRC).peer-reviewedIn this study, we tested the hypothesis that milk oligosaccharides may contribute not only to selective growth of bifidobacteria, but also to their specific adhesive ability. Human milk oligosaccharides (3′sialyllactose and 6′sialyllactose) and a commercial prebiotic (Beneo Orafti P95; oligofructose) were assayed for their ability to promote adhesion of Bifidobacterium longum subsp. infantis ATCC 15697 to HT-29 and Caco-2 human intestinal cells. Treatment with the commercial prebiotic or 3′sialyllactose did not enhance adhesion. However, treatment with 6′sialyllactose resulted in increased adhesion (4.7 fold), while treatment with a mixture of 3′- and 6′-sialyllactose substantially increased adhesion (9.8 fold) to HT-29 intestinal cells. Microarray analyses were subsequently employed to investigate the transcriptional response of B. longum subsp. infantis to the different oligosaccharide treatments. This data correlated strongly with the observed changes in adhesion to HT-29 cells. The combination of 3′- and 6′-sialyllactose resulted in the greatest response at the genetic level (both in diversity and magnitude) followed by 6′sialyllactose, and 3′sialyllactose alone. The microarray data was further validated by means of real-time PCR. The current findings suggest that the increased adherence phenotype of Bifidobacterium longum subsp. infantis resulting from exposure to milk oligosaccharides is multi-faceted, involving transcription factors, chaperone proteins, adhesion-related proteins, and a glycoside hydrolase. This study gives additional insight into the role of milk oligosaccharides within the human intestine and the molecular mechanisms underpinning host-microbe interactions.Science Foundation IrelandTeagasc Walsh Fellowship Programm
Coordinating government and community support for community language teaching in Australia: Overview with special attention to New South Wales
An overview of formal government language-in-education planning for community languages (CLs) that has been undertaken in Australia and New South Wales is provided, moving from the more informal programmes provided in the 1980s to school-oriented programmes and training at the turn of the century. These programmes depend on community support; for many of the teachers from the communities, methodological training is needed to complement their language and cultural skills. At the same time, Commonwealth (Federal) and State support for CL programmes has improved their quality and provides students with opportunities to study CLs at the senior secondary matriculation level. The paper concludes with specific recommendations for greater recognition of CL schools and for greater attention to CL teacher preparation
The Population of Tiny Near-Earth Objects Observed by NEOWISE
Only a very small fraction of the asteroid population at size scales
comparable to the object that exploded over Chelyabinsk, Russia has been
discovered to date, and physical properties are poorly characterized. We
present previously unreported detections of 106 close approaching near-Earth
objects (NEOs) by the Wide-field Infrared Survey Explorer mission's NEOWISE
project. These infrared observations constrain physical properties such as
diameter and albedo for these objects, many of which are found to be smaller
than 100 m. Because these objects are intrinsically faint, they were detected
by WISE during very close approaches to the Earth, often at large apparent
on-sky velocities. We observe a trend of increasing albedo with decreasing
size, but as this sample of NEOs was discovered by visible light surveys, it is
likely that selection biases against finding small, dark NEOs influence this
finding.Comment: Accepted to Ap
Magnetohydrodynamic activity inside a sphere
We present a computational method to solve the magnetohydrodynamic equations
in spherical geometry. The technique is fully nonlinear and wholly spectral,
and uses an expansion basis that is adapted to the geometry:
Chandrasekhar-Kendall vector eigenfunctions of the curl. The resulting lower
spatial resolution is somewhat offset by being able to build all the boundary
conditions into each of the orthogonal expansion functions and by the
disappearance of any difficulties caused by singularities at the center of the
sphere. The results reported here are for mechanically and magnetically
isolated spheres, although different boundary conditions could be studied by
adapting the same method. The intent is to be able to study the nonlinear
dynamical evolution of those aspects that are peculiar to the spherical
geometry at only moderate Reynolds numbers. The code is parallelized, and will
preserve to high accuracy the ideal magnetohydrodynamic (MHD) invariants of the
system (global energy, magnetic helicity, cross helicity). Examples of results
for selective decay and mechanically-driven dynamo simulations are discussed.
In the dynamo cases, spontaneous flips of the dipole orientation are observed.Comment: 15 pages, 19 figures. Improved figures, in press in Physics of Fluid
Beliefs about prescribed medication among older patients with polypharmacy: a mixed methods study in primary care
Background: Polypharmacy (≥5 medications) is common in older patients and is associated with adverse outcomes. Patients’ beliefs about medication can influence their expectations for medication, adherence, and willingness to deprescribe. Few studies have examined beliefs about prescribed medication among older patients with polypharmacy in primary care.Aim: To explore medication-related beliefs in older patients with polypharmacy and factors that might influence beliefs.Design and setting: A mixed methods study utilising data from a randomised controlled trial aiming to decrease potentially inappropriate prescribing in older patients (≥70 years) in Ireland.Method: Beliefs were assessed quantitatively and qualitatively. Participants completed the Beliefs about Medicines Questionnaire by indicating their degree of agreement with individual statements about medicines on a 5-point Likert scale. Semi-structured qualitative interviews were conducted with a purposive sample of participants. Interviews were transcribed verbatim and a thematic analysis conducted. Quantitative and qualitative data were analysed separately and triangulated during the interpretation stage.Results: In total, 196 patients were included (mean age 76.7 years, SD 4.9, 54% male), with a mean of 9.5 (SD 4.1) medications per patient. The majority (96.3%) believed strongly in the necessity of their medication, while 33.9% reported strong concerns. Qualitative data confirmed these coexisting positive and negative attitudes to medications and suggested the importance of patients’ trust in GPs in establishing positive beliefs and potential willingness to deprescribe.Conclusion: Participants reported strong beliefs in medications with coexisting positive and negative attitudes. The doctor–patient relationship may have influenced beliefs and attitudes towards medicines, highlighting the importance of strong doctor–patient relationships, which need to be considered in the context of deprescribin
Large scale flow effects, energy transfer, and self-similarity on turbulence
The effect of large scales on the statistics and dynamics of turbulent
fluctuations is studied using data from high resolution direct numerical
simulations. Three different kinds of forcing, and spatial resolutions ranging
from 256^3 to 1024^3, are being used. The study is carried out by investigating
the nonlinear triadic interactions in Fourier space, transfer functions,
structure functions, and probability density functions. Our results show that
the large scale flow plays an important role in the development and the
statistical properties of the small scale turbulence. The role of helicity is
also investigated. We discuss the link between these findings and
intermittency, deviations from universality, and possible origins of the
bottleneck effect. Finally, we briefly describe the consequences of our results
for the subgrid modeling of turbulent flows
Sustained effectiveness of a multifaceted intervention to reduce potentially inappropriate prescribing in older patients in primary care (OPTI-SCRIPT study)
BACKGROUND: Potentially inappropriate prescribing (PIP) is common in older people in primary care and can result in increased morbidity, adverse drug events and hospitalisations. We previously demonstrated the success of a multifaceted intervention in decreasing PIP in primary care in a cluster randomised controlled trial (RCT).
OBJECTIVE: We sought to determine whether the improvement in PIP in the short term was sustained at 1-year follow-up.
METHODS: A cluster RCT was conducted with 21 GP practices and 196 patients (aged ≥70) with PIP in Irish primary care. Intervention participants received a complex multifaceted intervention incorporating academic detailing, medicine review with web-based pharmaceutical treatment algorithms that provide recommended alternative treatment options, and tailored patient information leaflets. Control practices delivered usual care and received simple, patient-level PIP feedback. Primary outcomes were the proportion of patients with PIP and the mean number of potentially inappropriate prescriptions at 1-year follow-up. Intention-to-treat analysis using random effects regression was used.
RESULTS: All 21 GP practices and 186 (95 %) patients were followed up. We found that at 1-year follow-up, the significant reduction in the odds of PIP exposure achieved during the intervention was sustained after its discontinuation (adjusted OR 0.28, 95 % CI 0.11 to 0.76, P = 0.01). Intervention participants had significantly lower odds of having a potentially inappropriate proton pump inhibitor compared to controls (adjusted OR 0.40, 95 % CI 0.17 to 0.94, P = 0.04).
CONCLUSION: The significant reduction in the odds of PIP achieved during the intervention was sustained after its discontinuation. These results indicate that improvements in prescribing quality can be maintained over time.
TRIAL REGISTRATION: Current controlled trials ISRCTN41694007
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