3,914 research outputs found
The mystery of the 'Kite' radio source in Abell 2626: insights from new Chandra observations
We present the results of a new Chandra study of the galaxy cluster A2626.
The radio emission of the cluster shows a complex system of four symmetric arcs
without known correlations with the X-ray emission. The mirror symmetry of the
radio arcs toward the center and the presence of two optical cores in the
central galaxy suggested that they may be created by pairs of precessing radio
jets powered by dual AGNs inside the cD galaxy. However, previous observations
failed to observe the second jetted AGN and the spectral trend due to radiative
age along the radio arcs, thus challenging this interpretation. The new Chandra
observation had several scientific objectives, including the search for the
second AGN that would support the jet precession model. We focus here on the
detailed study of the local properties of the thermal and non-thermal emission
in the proximity of the radio arcs, in order to get more insights into their
origin. We performed a standard data reduction of the Chandra dataset deriving
the radial profiles of temperature, density, pressure and cooling time of the
intra-cluster medium. We further analyzed the 2D distribution of the gas
temperature, discovering that the south-western junction of the radio arcs
surrounds the cool core of the cluster. We studied the X-ray SB and spectral
profiles across the junction, finding a cold front spatially coincident with
the radio arcs. This may suggest a connection between the sloshing of the
thermal gas and the nature of the radio filaments, raising new scenarios for
their origin. A possibility is that the radio arcs trace the projection of a
complex surface connecting the sites where electrons are most efficiently
reaccelerated by the turbulence that is generated by the gas sloshing. In this
case, diffuse emission embedded by the arcs and with extremely steep spectrum
should be most visible at very low radio frequencies.Comment: 7 pages, 7 figures. Accepted for publication on A&
Colloidal, tribological and sensory properties of oral nutritional supplements
This study aims to evaluate the physicochemical and sensory properties of oral nutritional supplements (ONSs). High physical stability was measured in ONSs with mean particle sizes <0.33 !m and viscosity >19.3 mPa·s. ONSs formulated with dairy-soy protein mixtures displayed low friction coefficients, whereas ONSs containing dairy proteins alone had high friction coefficient values in the boundary regime. Sensory analysis revealed low to medium liking across the products and the highest preference was found in samples with the highest perceived 'sweetness', 'vanilla aroma' and 'thickness'. The results will underpin the formulation of novel ONSs with good physical stability and sensory acceptability
Gold nanoparticles as novel agents for cancer therapy
Gold nanoparticles are emerging as promising agents for cancer therapy and are being investigated as drug carriers, photothermal agents, contrast agents and radiosensitisers. This review introduces the field of nanotechnology with a focus on recent gold nanoparticle research which has led to early-phase clinical trials. In particular, the pre-clinical evidence for gold nanoparticles as sensitisers with ionising radiation in vitro and in vivo at kilovoltage and megavoltage energies is discussed
Understanding the field of rural health academic research: a national qualitative, interview-based study
Introduction: Rural areas depend on a specific evidence base that directly informs their unique health systems and population health context. Developing this evidence base and its translation depends on a trained rural health academic workforce. However, to date, there is limited description of this workforce and the field of rural health research. This study aimed to characterise this field to inform how it can be fostered.
Methods: Qualitative semi-structured interviews of 50-70 minutes duration were conducted with 17 early career rural health researchers based in Australian rural and remote communities, to explore their professional background, training and research experiences.
Results: Six key themes emerged: becoming a rural health researcher; place-based research that has meaning; generalist breadth; trusted partnerships; small, multidisciplinary research teams; and distance and travel. The field mostly attracted researchers already living in rural areas. Researchers were strongly inspired by doing research that effected local change and addressed inequalities. Their research required a generalist skill set, applying diverse academic and local contextual knowledge that was broader than their doctoral training. Research problems were complex, diverse and required novel methods. Research occurred within trusted community partnerships spanning wide geographic catchments, stakeholders and organisations. This involved extensive leadership, travel and time for engagement and research co-production. Responding to the community was related to researchers doing multiple projects of limited funding. The field was also depicted by research occurring in small collegial, multidisciplinary teams focused on 'people' and 'place' although researchers experienced geographic and professional isolation with respect to their field and main university campuses. Researchers were required to operationalise all aspects of research processes with limited help. They took available opportunities to build capacity in the face of limited staff and high community demand.
Conclusion: The findings suggest that rural health research is highly rewarding, distinguished by a generalist scope and basis of 'rural' socially accountable research that is done in small, isolated teams of limited resources. Strategies are needed to grow capacity to a level fit to address the level of community demand but these must embrace development of the rural academic entry pathway, the generalist breadth and social accountability of this field, which underpins the perceived value of rural health research for rural communities
Particle Impact Analysis of Bulk Powder During Pneumatic Conveyance
Fragmentation of powders during transportation is a common problem for manufacturers of food and pharmaceutical products. We illustrate that the primary cause of breakage is due to inter-particle collisions, rather than particle-wall impacts, and provide a statistical mechanics model giving the number of collisions resulting in fragmentation
Deep Chandra Observations of HCG 16 - I. Active Nuclei, Star formation and Galactic Winds
We present new, deep Chandra X-ray and Giant Metrewave Radio Telescope
610~MHz observations of the spiral-galaxy-rich compact group HCG 16, which we
use to examine nuclear activity, star formation and the high luminosity X-ray
binary populations in the major galaxies. We confirm the presence of obscured
active nuclei in NGC 833 and NGC 835, and identify a previously unrecognized
nuclear source in NGC 838. All three nuclei are variable on timescales of
months to years, and for NGC 833 and NGC 835 this is most likely caused by
changes in accretion rate. The deep Chandra observations allow us to detect for
the first time an Fe-K emission line in the spectrum of the Seyfert 2
nucleus of NGC 835. We find that NGC 838 and NGC 839 are both
starburst-dominated systems, with only weak nuclear activity, in agreement with
previous optical studies. We estimate the star formation rates in the two
galaxies from their X-ray and radio emission, and compare these results with
estimates from the infra-red and ultra-violet bands to confirm that star
formation in both galaxies is probably declining after galaxy-wide starbursts
were triggered ~400-500 Myr ago. We examine the physical properties of their
galactic superwinds, and find that both have temperatures of ~0.8 keV. We also
examine the X-ray and radio properties of NGC 848, the fifth largest galaxy in
the group, and show that it is dominated by emission from its starburst.Comment: 18 pages, 11 figures, 11 tables, accepted for publication in ApJ;
updated references and fixed typos identified at proof stag
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